ArticleLiterature Review

Cruciferous vegetables intake and risk of prostate cancer: A meta-analysis

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Abstract

To evaluate the relationship between cruciferous vegetables intake and risk of prostate cancer. A systematic literature search up to June 2011 was carried out in PubMed, and the references of retrieved articles were screened. The summary relative risks with 95% confidence interval for the highest versus the lowest intake of cruciferous vegetables were calculated. Heterogeneity and publication bias were also evaluated. Seven cohort and six population-based case-control studies met the inclusion criteria of the meta-analysis. A significantly decreased prostate cancer risk was observed overall in the cruciferous vegetables intake group (relative risks = 0.90; 95% confidence interval 0.85-0.96) and the subgroup of case-control studies (relative risks = 0.79; 95% confidence interval 0.69-0.89), but not in cohort studies (relative risks = 0.95; 95% confidence interval 0.88-1.02). No heterogeneity and publication bias were detected across studies. Cruciferous vegetables intake is related to the decreased risk of prostate cancer. Because of the limited number of studies, further prospective studies are needed to explore the protective effect of cruciferous vegetables on prostate cancer.

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... Consistent with cell and animal models, epidemiological studies have demonstrated a link between the intake of cruciferous vegetables (particularly the active compound SFN) and a reduction in the incidence or progression of PCa [39][40][41][42][43]. A large data set meta-analysis including six population-based case-control studies and seven cohort studies showed a significantly decreased PCa risk overall for cruciferous vegetable intake (RR = 0.90; 95% CI: 0.85-0.96) ...
... as well as in the subgroup of case-control studies (RR = 0.79; 95% CI: 0.69-0.89) [39]. In addition, a prospective study involving patients with extra-prostatic disease documented a 59% reduced risk of PCa progression for highest vs. lowest intake of cruciferous vegetables (HR: 0.41; 95% CI: 0.22-0.76, ...
... The S-alk(en)yl-L-cysteine sulfoxides (SACSOs) are the main sulfur-containing constituents within allium vegetables, and are precursors to the bioactive components. Alliin (S-allylcysteine sulfoxide) is the major SACSO found in garlic, and isoalliin (trans-(+)-S-(propen-1-yl)-L-cysteine sulfoxide) is the predominant SACSO in onions [37][38][39]. When garlic is cut, chopped, or crushed, the disruption of the cell membranes causes the transformation of SACSOs to sulfenic acid intermediates by the enzyme alliinase, which is released from the vacuoles of the plant as part of its defence system. ...
Article
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Prostate cancer has become the most common form of non-cutaneous (internal) malignancy in men, accounting for 26% of all new male visceral cancer cases in the UK. The aetiology and pathogenesis of prostate cancer are not understood, but given the age-adjusted geographical variations in prostate cancer incidence quoted in epidemiological studies, there is increasing interest in nutrition as a relevant factor. In particular, foods rich in phytochemicals have been proposed to reduce the risk of prostate cancer. Epidemiological studies have reported evidence that plant-based foods including cruciferous vegetables, garlic, tomatoes, pomegranate and green tea are associated with a significant reduction in the progression of prostate cancer. However, while there is well-documented mechanistic evidence at a cellular level of the manner by which individual dietary components may reduce the risk of prostate cancer or its progression, evidence from intervention studies is limited. Moreover, clinical trials investigating the link between the dietary bioactives found in these foods and prostate cancer have reported varied conclusions. Herein, we review the plant bioactives for which there is substantial evidence from epidemiological and human intervention studies. The aim of this review is to provide important insights into how particular plant bioactives (e.g., sulphur-containing compounds, carotenoids and polyphenols) present in commonly consumed food groups may influence the development and progression of prostate cancer.
... Epidemiological studies have suggested a negative association between consumption of cruciferous vegetables and incidence or progression of prostate cancer (3)(4)(5). The protective activity has been associated with the biological activity of degradation products of glucosinolates, sulfur-containing glycosides that accumulate in these vegetables. ...
... Data shown are median (IQR).4 PSA at diagnosis missing for 3 patients on Diet X, 1 on Diet Y, and 1 on Diet Z.5 Gleason score at diagnosis missing for 1 patient on Diet Z. ...
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Background Epidemiological evidence suggests that consumption of cruciferous vegetables is associated with reduced risk of prostate cancer progression, largely attributed to the biological activity of glucosinolate degradation products, such as sulforaphane derived from glucoraphanin. Because there are few therapeutic interventions for men on active surveillance for prostate cancer to reduce the risk of cancer progression, dietary approaches are an appealing option for patients. Objective We evaluated whether consumption of a glucoraphanin-rich broccoli soup for 1 y leads to changes in gene expression in prostate tissue of men with localized prostate cancer. Methods Forty-nine men on active surveillance completed a 3-arm parallel randomized double-blinded intervention study for 12 mo and underwent transperineal template biopsy procedures and dietary assessment at the start and end of the study. Patients received a weekly 300 mL portion of soup made from a standard broccoli (control) or from 1 of 2 experimental broccoli genotypes with enhanced concentrations of glucoraphanin, delivering 3 and 7 times that of the control, respectively. Gene expression in tissues from each patient obtained before and after the dietary intervention was quantified by RNA sequencing followed by gene set enrichment analyses. Results In the control arm, there were several hundred changes in gene expression in nonneoplastic tissue during the 12 mo. These were associated with an increase in expression of potentially oncogenic pathways including inflammation processes and epithelial–mesenchymal transition. Changes in gene expression and associated oncogenic pathways were attenuated in men on the glucoraphanin-rich broccoli soup in a dose-dependent manner. Although the study was not powered to assess clinical progression, an inverse association between consumption of cruciferous vegetables and cancer progression was observed. Conclusion Consuming glucoraphanin-rich broccoli soup affected gene expression in the prostate of men on active surveillance, consistent with a reduction in the risk of cancer progression. This trial was registered at clinicaltrials.gov as NCT01950143.
... Despite the fact that cereals increase fiber intake, the analogous consumption of red and processed meat seem to positively correlate with PCa (10,11). Interestingly, a meta-analysis of 13 studies suggested that the consumption of cruciferous vegetables significantly correlated with a reduced PCa risk (12). ...
... Systematic cruciferous intake was, also, associated with reduced risk of PCa progression (19,20). A meta-analysis by Liu et al. showed a significantly decrease for PCa when cruciferous vegetables were consumed (12). However, these results were not validated by Meng et al. (21). ...
Preprint
Purpose Dietary modifications have been correlated with survival in several neoplasia, such as prostate cancer. The present study was designed to investigate the association between the Mediterranean diet and prostate cancer risk. Methods A retrospective analysis of patients with a high suspicion of suffering from prostate cancer (PCa) who underwent prostate biopsy was performed. According to histopathology, two groups were generated, the PCa group and the Healthy group. The dietary profile of our study population was implemented, based on a modified MDS (Mediterranean Diet Score) questionnaire. A logistic regression model was used for the interpretation of our data. Results In total, 431 patients with prostate cancer and 279 healthy men were included in our study. The demographic characteristics of the patients were comparable. Daily consumption of white meat (OR: 0.59), dairy products (OR: 0.64), nuts (OR: 0.63) and whole grains (OR: 0.55) was higher in healthy males. Infrequent consumption of vegetables was linked with an increased rate of PCa (OR: 2.55). Interestingly daily consumption of processed meat rates was higher in healthy men. However, a significant correlation between specific intake products or frequency and the incidence of PCa was not established. Conclusions Although, an association between the dietary patterns and PCa was not determined, components consumption patterns displayed a higher daily intake rate of white meat, dairy products, nuts and whole grains. Further prospective trials are required to validate the effect of Mediterranean diet in the incidence and mortality of PCa patients.
... Indole-3-carbinol and 3,3′-diindolymethane suppress angiogenesis in vivo and in vitro, being the later the one showing the strongest antiangiogenic activity. Both compounds are able to inactivate the ERK1/2 pathway, but they differ in their potential to Diets high in cruciferous vegetables have been correlated with a lower risk of incidence and aggressiveness of prostate cancer in several case-control studies [151][152][153][154]. This is in agreement with results from some cohort studies, although it could not be confirmed by others [155][156][157][158][159]. A significantly decreased prostate cancer risk was observed overall in the cruciferous vegetables' intake group in a meta-analysis. ...
... This is in agreement with results from some cohort studies, although it could not be confirmed by others [155][156][157][158][159]. A significantly decreased prostate cancer risk was observed overall in the cruciferous vegetables' intake group in a meta-analysis. Moreover, results from the first clinical trial of sulforaphane-rich extracts in men with prostate cancer revealed a positive effect in decreasing PSA levels, in spite of having not achieved its primary endpoint [153,154]. ...
Article
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The number of cancer cases worldwide keeps growing unstoppably, despite the undeniable advances achieved by basic research and clinical practice. Urologic tumors, including some as prevalent as prostate, bladder or kidney tumors, are no exceptions to this rule. Moreover, the fact that many of these tumors are detected in early stages lengthens the duration of their treatment, with a significant increase in health care costs. In this scenario, prevention offers the most cost-effective long-term strategy for the global control of these diseases. Although specialized diets are not the only way to decrease the chances to develop cancer, epidemiological evidence support the role of certain plant-derived foods in the prevention of urologic cancer. In many cases, these plants are rich in antiangiogenic phytochemicals, which could be responsible for their protective or angiopreventive properties. Angiogenesis inhibition may contribute to slow down the progression of the tumor at very different stages and, for this reason, angiopreventive strategies could be implemented at different levels of chemoprevention, depending on the targeted population. In this review, epidemiological evidence supporting the role of certain plant-derived foods in urologic cancer prevention are presented, with particular emphasis on their content in bioactive phytochemicals that could be used in the angioprevention of cancer.
... Brassicaceae vegetables are the most promising food components in cancer prophylaxis. As demonstrated in several epidemiologic studies, consumption of these plants significantly reduces the risk of common human cancers, including lung [1,2] stomach [1], breast [3] or prostate cancer [4,5]. The chemopreventive activity of Brassica plants is associated with the presence of secondary plant metabolites: glucosinolates (GLs) [6]. ...
... The presented here results confirmed the association between cytotoxicity and total concentration of ITC and indoles; only for samples with high conversion rates of GLs to ITC and indoles cytotoxic effect was observed (Fig. 3). In addition, for a number of other cancer cell lines such as lung, stomach, breast, colon, prostate cancer, it has been reported that the composition of ITC influenced the cell growth [1][2][3][4][5]. Moreover, red cabbage extract was demonstrated to selectively inhibit proliferation of HeLa and HepG2 cell lines, but did not have such an effect on normal cell PBMC [75]. ...
Article
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The studies on the characterisation of glucosinolates (GLs) and their breakdown products in Brassicaceae species focus mainly on the edible parts. However, other products, e.g., dietary supplements, may be produced also from non-edible parts such as roots or early forms of growth: seeds or sprouts. Biological activity of these products depends on quantitative and qualitative GL composition, but is also strictly determined by GL conversion rate to chemopreventive isothiocyanates (ITC) and indoles. The aim of this study was to evaluate the conversion rate of GLs to ITC and indoles for various plant parts of chosen Brassica species in relation to their biological activity. For this purpose, the composition of GLs and their degradation products was determined as well as activity of myrosinase. Toxicological part of studies involved: MTT assay, restriction analysis, comet assay and Ames test. The composition of GLs and conversion rate to ITC and indoles was found to differ significantly between Brassica species and individual parts of the plant. The highest efficiency of conversion was observed for edible parts of plants: more than 70%, while in sprouts, it reached less than 1%, though myrosinase activity did not differ. The conversion rate directly affected biological activity of plant material. Higher concentration of ITC/indoles in the sample led to the increase of cytotoxicity. Majority of tested samples were able to induce covalent DNA modification in cell-free system. It was also confirmed that the presence of indolic GLs and products of their degradation stimulated mutagenicity, but did not lead to DNA fragmentation in cultured cells.
... Epidemiological studies have found an inverse relationship between consumption of cruciferous vegetables (such as broccoli or cauliflower) and the risk of PCa. Isothiocyanates in this group of vegetables can suppress cell growth by inhibiting androgen receptor transcription (32,33). Furthermore, vegetables of the genus Allium (e.g., onion, garlic) can stimulate the immune system, inhibit cell growth, modulate the expression of androgen-responding genes and induce apoptosis, playing a protective role against PCa (34). ...
... Free radical augmentation is generated from beta-oxidation during fat metabolism and induction of prostate inflammation, causing a significant increase in the risk of progression (101). Some authors propose inhibition of fatty acid synthase as a protective mechanism; however, documented studies are inconclusive (33,42,53,71). ...
Article
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Objective: This review aimed to analyze interventions raised within primary and tertiary prevention concerning the disease's incidence, progression, and recurrence of Prostate Cancer (PCa). Priority was given to the multidisciplinary approach of PCa patients with an emphasis on modifiable risk factors. Materials and methods: We conducted a comprehensive literature review in the following databases: Embase, Central, and Medline. We included the most recent evidence assessing cohort studies, case-control studies, clinical trials, and systematic reviews published in the last five years. We only included studies in adults and in vitro or cell culture studies. The review was limited to English and Spanish articles. Results: Preventive interventions at all levels are the cornerstone of adherence to disease treatment and progression avoidance. The relationship in terms of healthy lifestyles is related to greater survival. The risk of developing cancer is associated to different eating habits, determined by geographic variations, possibly related to different genetic susceptibilities. Discussion: PCa is the second most common cancer in men, representing a leading cause of death among men in Latin America. Prevention strategies and healthy lifestyles are associated with higher survival rates in PCa patients. Also, screening for anxiety and the presence of symptoms related to mood disorders is essential in the patient's follow-up concerning their perception of the condition.
... Several epidemiological studies over the last decades supported the fact that Brassica vegetables are promising in cancer prevention. Meta-analysis that combined results of different authors showed an inverse relationship between cruciferous vegetable consumption and the risk of cancers of the reproductive system (Liu, Mao, Cao and Xie 2012;Liu and Live, 2013;Han, Li and Yu 2014), ...
Article
Kale (Brassica oleracea var. acephala) is a cruciferous vegetable, characterized by leaves along the stem, which, in recent years, have gained a great popularity as a ´superfood´. Consequently, in a popular culture it is listed in many ´lists of the healthiest vegetables´. Without the doubt, a scientific evidence support the fact that cruciferous vegetables included in human diet can positively affect health and well-being, but remains unclear why kale is declared superior in comparison with other cruciferous. It is questionable if this statement about kale is triggered by scientific evidence or by some other factors. Our review aims to bring an overview of kale's botanical characteristics, agronomic requirements, contemporary and traditional use, macronutrient and phytochemical content and biological activity, in order to point out the reasons for tremendous kale popularity.
... Consumption of brassica vegetables has been inversely associated with the risk of breast, colorectal, prostate, and lung cancers (Liu, Mao, Cao, & Xie, 2012;Liu & Lv, 2013;Mori et al., 2017;Wu, Yang, Wang, Han, & Xiang, 2013), a result that has considerable support in preclinical studies (Bhattacharya et al., 2010;Chen, Wallig, & Jeffery, 2016;Melchini et al., 2013;Tang & Zhang, 2004;Zhang, Talalay, Cho, & Posner, 1992). The anti-cancer activity of brassica vegetables is generally associated with glucosinolates, which in the presence of plant or bacterial myrosinase, are converted to bioactive isothiocyanates, indoles, and other products. ...
Article
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Brassica vegetables may modulate cancer risk by regulation of xenobiotic metabolizing enzymes (XMEs). In a randomized crossover study, the effect of kale consumption on CYP1A2, CYP2A6, XO, and NAT2 activity was determined by urinary caffeine metabolite ratios, UGT1A1 activity by serum bilirubin concentrations, and GSTA protein and GST activity in blood by ELISA. Adults (n = 25) consumed a basal diet supplemented with kale and radish for 14 days or control vegetables. The kale diet increased CYP1A2 activity by 16.4% on day 8 and 15.2% on day 15 compared to control. Conjugated bilirubin was reduced by the kale diet, decreasing from 19.4 to 14.3 to 9.5% of total bilirubin on days 1, 8, and 15, respectively, which may be explained by induction of MRP2. Other XMEs were not affected by diet. The implications of these results for cancer risk will be clarified as the functions of these XMEs become better understood.
... 95%CI=0.53-0.86) (149). Another meta-analysis of studies conducted over 18 years in Europe including a total of 1294 of prostate cancer patients and 11,492 controls has shown that consumption of cruciferous vegetables was associated with a 13% reduction in prostate cancer risk (OR=0.87, ...
Article
Background/aim: Prostate cancer is one of the most common cancers in men which remains a global public health issue. Treatment of prostate cancer is becoming increasingly intensive and aggressive, with a corresponding increase in resistance, toxicity and side effects. This has revived an interest in nontoxic and cost-effective preventive strategies including dietary compounds due to the multiple effects they have been shown to have in various oncogenic signalling pathways, with relatively few significant adverse effects. Materials and methods: To identify such dietary components and micronutrients and define their prostate cancer-specific actions, we systematically reviewed the current literature for the pertinent mechanisms of action and effects on the modulation of prostate carcinogenesis, along with relevant updates from epidemiological and clinical studies. Results: Evidence from various recent experimental, clinical and epidemiological studies indicates that select dietary micronutrients (i.e., lycopene, epigallocatechin gallate, sulforaphane, indole-3-carbinol, resveratrol, quercetin, curcumin & piperine) and zinc play a key role in prostate cancer prevention and progression and therefore hold great promise for the future overall management of prostate cancer. Conclusion: A formulation that comprises these micronutrients using the optimal, safest form and dosing should be investigated in future prostate cancer chemoprevention studies and as part of standard prostate cancer therapy.
... Dietary factors and specific nutrients have been frequently investigated for their potential roles in carcinogenesis. Those that have been reported to be associated with decreased PC or APC risk include intakes of lycopene, found in high levels in tomatoes [10,11], fruits and vegetables [12,13], cruciferous vegetables such as broccoli, cabbage, and cauliflower [14,15], allium vegetables including onion, leek, and garlic 1 3 [16,17], as well as fish [18,19]. On the other hand, high intakes of processed meat [20,21], dairy products [22,23], and calcium [24,25] have been reported to be associated with increased risk of PC, APC, and PC-specific mortality. ...
Article
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Purpose Diet and body size may affect the risk of aggressive prostate cancer (APC), but current evidence is inconclusive. Methods A case–control study was conducted in men under 75 years of age recruited from urology practices in Victoria, Australia; 1,254 with APC and 818 controls for whom the presence of prostate cancer had been excluded by biopsy. Dietary intakes were assessed using a validated food frequency questionnaire. Multivariable unconditional logistic regression estimated odds ratios and confidence intervals for hypothesized risk factors, adjusting for age, family history of prostate cancer, country of birth, socioeconomic status, smoking, and other dietary factors. Results Positive associations with APC (odds ratio, 95% confidence intervals, highest vs. lowest category or quintile) were observed for body mass index (1.34, 1.02–1.78, Ptrend = 0.04), and trouser size (1.54, 1.17–2.04, Ptrend = 0.001). Intakes of milk and all dairy products were inversely associated with APC risk (0.71, 9.53–0.96, Ptrend = 0.05, and 0.64, 0.48–0.87, Ptrend = 0.012, respectively), but there was little evidence of an association with other dietary variables (Ptrend > 0.05). Conclusions We confirmed previous evidence for a positive association between body size and risk of APC, and suggest that consumption of dairy products, and milk more specifically, is inversely associated with risk.
... Many factors included diet, lifestyle, environmental, and genetic factors can contribute to enhance the risk factors for PCa [2]. Several studies found inverse relationships between total fruit and vegetable intake [3] or cruciferous vegetable intake and PCa risk [4][5][6][7][8]. ...
Article
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Lycopene is more bioavailable in processed tomato products than in raw tomatoes, since arrangement of cis-isomers of lycopene during food processing and storage may increase its biological activity. The aim of the study is evaluate the influence of lycopene content from different tomato-based food products (extract, paste, ketchup and sauce) on cell proliferation, cell cycle, and rate of apoptosis of human prostate cancer cell lines. DU-145 and PC-3 cell lines were treated with lycopene content from different tomato-based food products (500–5000 μg/mL) for 96 h. The data showed a decrease in cell viability in both DU-145 and PC-3 cells after treatment with all lycopene extracts from tomato-based food products. Analysis of cell cycle revealed a decrease in the percentage of prostate cancer cells in G0/G1 and G2/M phases after 96 h of treatment when using lycopene content from tomato paste and tomato extract. However, lycopene extracted from tomato sauce and ketchup promoted a decrease in the percentage of cells in G0/G1 phase and an increase in S and G2/M phases after 96 h of treatment. Lycopene content from all of those tomato-based food products also increased apoptosis in both prostate cancer cell lines. In this regard, lycopene has proved to be a potent inhibitor of cell viability, arrest cell cycle and increase the apoptosis in human prostate cancer cells, suggesting an effect in the balance of human prostate cancer cell lines growth.
... . Commonly, epidemiological studies have given inconsistent conclusions. In order to pool the relevant studies together and gain more clear conclusions, different metaanalyses were performed which demonstrated an inverse relationship between cruciferous vegetable consumption and the risk of breast cancer (Liu and Lv, 2013), ovarian cancer (Han et al., 2014), prostate cancer (Liu et al., 2012), gastric cancer (Wu et al., 2013c), colorectal cancer , lung cancer (Wu et al., 2013b), bladder cancer (Liu et al., 2013a), and renal cell carcinoma (Liu et al., 2013b). Mechanisms underlying the anticancer activity of Brassica vegetables have been attributed to the decomposition products of the abundant secondary metabolites, glucosinolates (Jahangir et al., 2009). ...
... [2] Physical activities, coffee consumption, statin use, intake of certain vegetables also have been linked with the prevention of prostate cancer. [3][4][5][6][7] Recently, it was proposed that metformin had additional beneficial anticarcinogenic effects in human cancers, [8,9] including prostate cancer. [10] Metformin, a biguanide, is the most widely prescribed antidiabetic drug worldwide due to its clinical effectiveness and tolerability. ...
Article
Background: The relationship between metformin use and the risk of prostate cancer is still inconclusive. Therefore, we performed a systematic review and meta-analysis of all eligible cohort studies to evaluate a potential association of metformin use with prostate cancer risk. Methods: A comprehensive literature search was performed in PubMed and Web of Science databases through July 2018. A DerSimonian and Laird random-effects model was applied to calculate the pooled relative risk (RR) and its 95% confidence interval (CI). Results: Eighteen cohort or nested case-control studies were included in this study with a total of 52,328 cases. In a random-effect pooled analysis, metformin use was not significantly associated with the risk of prostate cancer (RR 0.97, 95% CI 0.80-1.16, P = .711). Statistically significant heterogeneity was identified among included studies (P < .001, I = 98.1%). Sensitivity analysis indicated that no single study dominated the pooled RR. Conclusion: The present large meta-analysis of cohort studies did not find an association between metformin use and prostate cancer risk.
... I když výsledky nejsou zcela jednotné, studie naznačují pozitivní vliv konzumace košťálové zeleniny na riziko vzniku kardiovaskulárních chorob, různých typů nádorů vč. nádoru prostaty a také na celkovou úmrtnost [93][94][95][96][97][98][99][100]. Např. ...
... A recent meta-analysis showed that consumption of cruciferous vegetables is associated with a reduction in PC risk [92]. It should be noted that these epidemiological studies were not limited to cruciferous vegetables which contain sulphoraphane. ...
... [3] Additional but less established risk factors include physical activity, body mass index, and some dietary factors. [4][5][6][7] Emerging studies have indicated that the coagulation cascade and thrombocytes implicated in the development and progression of cancer, and that anticoagulant drugs could in theory improve prognosis. [8,9] For instance, activated platelets release secretory factors, such as proangiogenic regulatory proteins, chemokines, and microparticles within the microenvironment, to promote tumor growth and metastasis. ...
Article
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Background: Vitamin K antagonists (VKAs) may have potential antitumor effects in prostate cancer. However, the findings of observational studies are inconsistent. The purpose of the present study was to estimate the quantitative association between VKAs use and prostate cancer risk by combining the results of all eligible observational studies. Methods: PubMed and Web of Science database were searched from inception until May, 2018. A DerSimonian random-effects model was used to combine the studies. Study heterogeneity was measured using the chi-squared and I statistics. Results: Six eligible studies were eventually included in our meta-analysis. There was an inverse but not statistically significant association between ever use of VKAs and the risk of prostate cancer (relative risk [RR] 0.84, 95% confidence interval [CI] 0.70-1.01, P = .063) with large heterogeneity across studies (P < .001 for heterogeneity, I = 94.6%). When analysis restricted to long term of VKAs user (>3 years), the pooled risk estimate was 0.83 (0.77-0.90) without obvious heterogeneity (P = .597, I = 0.0%). Conclusion: This meta-analysis indicates that VKAs use may be associated with a decreased risk of prostate cancer, especially in long-term users.
... Several epidemiologic studies found inverse relationships between total fruit and vegetable intake [62], including cruciferous vegetable intake, and PCa risk [63,64]. In addition to the cruciferous vegetables discussed above, several other foods have been investigated, in particular green tea, tomato sauce and allium vegetables (onions, garlic, and scallions). ...
Article
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This review covers research done on the prevention and treatment of prostate cancer with a plant-based diet. Epidemiological studies have strongly implicated diet as a major modulator of prostate cancer risk. The risk of prostate cancer in vegetarians is less than half of non-vegetarians. While plant-based foods have been shown to decrease the risk of prostate cancer, animal-derived foods increase the risk it in a dose dependent manner. Intake of saturated fat and cholesterol found in animal derived foods are independent risk factors for prostate cancer, contributing further to the higher risk that nonvegetarians have. Other risk factors include a higher intake of carcinogenic persistent organic pollutants that bioconcentrate in animal adipose tissue and known carcinogens such as heterocyclic amines and polycyclic aromatic hydrocarbons that result from consuming cooked, fried, or barbecued meats. Persistent organic pollutants have been shown to be etiologic factors. Interventional studies have shown that a plant-based diet effectively halted or slowed the progression of most prostate cancer patients with a Gleason Score of less than seven. Results were maintained over a four-year period. Active tumor suppression for patients paced on a plant-based diet have been demonstrated. While many patients are placed on a passive watchful waiting protocol adding a plant- based diet can transform the protocol to active treatment.
... High intake of cruciferous vegetables is associated with decreases in risk of colorectal, lung, prostate and breast cancers. (24)(25)(26)(27) High intake of allium family vegetables is associated with decreased risk of cancers of the digestive tract, breast, ovary, prostate, and kidney. (28) High mushroom intake is associated with substantial decreases in breast cancer risk. ...
Article
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Risk of many of the most common cancers, such as those of the prostate, breast, and colorectum, is substantially affected by lifestyle factors. However, there is an alarming lack of awareness among the American public regarding the associations between dietary and other lifestyle factors and cancer risk. The public is largely unaware that an estimated 50 percent of common cancers are preventable via healthful lifestyle practices. This lack of knowledge undermines the perceived importance of behavioral change and the promotion of primary prevention strategies aimed to improve the health of our population. Physicians and other experts are in a unique position to counteract confusing media messages and raise awareness of the value of preventive lifestyle behaviors.
... An association between increased cruciferous vegetable intake and a reduced risk of developing, or being diagnosed with, prostate cancer has been reported (6). Cruciferous vegetables, such as broccoli and broccoli sprouts, are a rich source of glucosinolates (7). ...
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Background Cruciferous vegetables have been associated with the chemoprevention of cancer. Epigenetic regulators have been identified as important targets for prostate cancer chemoprevention. Treatment of human prostate cancer cells with sulforaphane (SFN), a chemical from broccoli and broccoli sprouts, inhibits epigenetic regulators such as histone deacetylase (HDAC) enzymes, but it is not known whether consumption of a diet high in broccoli sprouts impacts epigenetic mechanisms in an in vivo model of prostate cancer. Objective In the transgenic adenocarcinoma of the mouse prostate (TRAMP) model, we tested the hypothesis that a broccoli sprout diet suppresses prostate cancer, inhibits HDAC expression, alters histone modifications, and changes the expression of genes regulated by HDACs. Methods TRAMP mice were fed a 15% broccoli sprout or control AIN93G diet; tissue samples were collected at 12 and 28 wk of age. Results Mice fed broccoli sprouts had detectable amounts of SFN metabolites in liver, kidney, colon, and prostate tissues. Broccoli sprouts reduced prostate cancer incidence and progression to invasive cancer by 11- and 2.4-fold at 12 and 28 wk of age, respectively. There was a significant decline in HDAC3 protein expression in the epithelial cells of prostate ventral and anterior lobes at age 12 wk. Broccoli sprout consumption also decreased histone H3 lysine 9 trimethylation in the ventral lobe (age 12 wk), and decreased histone H3 lysine 18 acetylation in all prostate lobes (age 28 wk). A decline in p16 mRNA levels, a gene regulated by HDAC3, was associated with broccoli sprout consumption, but no significant changes were noted at the protein level. Conclusions Broccoli sprout intake was associated with a decline in prostate cancer occurrence and HDAC3 protein expression in the prostate, extending prior work that implicated loss of HDAC3/ corepressor interactions as a key preventive mechanism by SFN in vivo.
... Cruciferous vegetables have been of great interest. Numerous meta-analyses have shown the beneficial effect of cruciferous vegetables on breast, lung, colorectal, gastric, pancreatic, renal, prostate and other cancers (3)(4)(5)(6)(7)(8)(9)(10)(11) . The anti-carcinogenic effect of cruciferous vegetables against various cancers may be owing to the high levels of glucosinolates (GSL) (12) , which can hydrolyse into indole-3-carbinol and isothiocyanates (ITC) by plant myrosinase and gastrointestinal microflora. ...
Article
Although previous studies have investigated the association of cruciferous vegetable consumption with breast cancer risk, few studies focused on the association between bioactive components in cruciferous vegetables, glucosinolates (GSL) and isothiocyanates (ITC), and breast cancer risk. This study aimed to examine the association between consumption of cruciferous vegetables and breast cancer risk according to GSL and ITC contents in a Chinese population. A total of 1485 cases and 1506 controls were recruited into this case–control study from June 2007 to March 2017. Consumption of cruciferous vegetables was assessed using a validated FFQ. Dietary GSL and ITC were computed by using two food composition databases linking GSL and ITC contents in cruciferous vegetables with responses to the FFQ. The OR and 95 % CI were assessed by unconditional logistic regression after adjusting for the potential confounders. Significant inverse associations were found between consumption of cruciferous vegetables, GSL and ITC and breast cancer risk. The adjusted OR comparing the highest with the lowest quartile were 0·51 (95 % CI 0·41, 0·63) for cruciferous vegetables, 0·54 (95 % CI 0·44, 0·67) for GSL and 0·62 (95 % CI 0·50, 0·76) for ITC, respectively. These inverse associations were also observed in both premenopausal and postmenopausal women. Subgroup analysis by hormone receptor status found inverse associations between cruciferous vegetables, GSL and ITC and both hormone-receptor-positive or hormone-receptor-negative breast cancer. This study indicated that consumption of cruciferous vegetables, GSL and ITC was inversely associated with breast cancer risk among Chinese women.
... The data obtained showed that the inhibition of the deacetylation of histones is driven by SFN [70,71]. Not only preclinical studies but also studies in humans showed that, by taking SFN, a reduction in prostate cancer incidence and progression could be obtained [72,73]. The randomized double-blinded controlled trial named the "Effect of Sulforaphane on prostate CAncer PrEvention (ESCAPE)" demonstrated that taking 4-methylsulphinylbutyl glucosinolate (which is converted into SFN) for 12 months reduced the expression of genes that could be connected to the oncogenic pathway. ...
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The broad spectrum of the mechanism of action of immune-boosting natural compounds as well as the complex nature of the food matrices make researching the health benefits of various food products a complicated task. Moreover, many routes are involved in the action of most natural compounds that lead to the inhibition of chronic inflammation, which results in a decrease in the ability to remove a pathogen asymptomatically and is connected to various pathological events, such as cancer. A number of cancers have been associated with inflammatory processes. The current review strives to answer the question of whether plant-derived sulfur compounds could be beneficial in cancer prevention and therapy. This review focuses on the two main sources of natural sulfur compounds: alliaceous and cruciferous vegetables. Through the presentation of scientific data which deal with the study of the chosen compounds in cancer (cell lines, animal models, and human studies), the discussion of food processing’s influence on immune-boosting food content is presented. Additionally, it is demonstrated that there is still a need to precisely demonstrate the bioavailability of sulfur-containing compounds from various types of functional food, since the inappropriate preparation of vegetables can significantly reduce the content of beneficial sulfur compounds. Additionally, there is an urgent need to carry out more epidemiological studies to reveal the benefits of several natural compounds in cancer prevention and therapy.
... Multiple epidemiological studies have linked consumption of brassica vegetables with reduced risk for cancers including bladder, breast, colorectal, prostate, lung, and stomach cancers (1)(2)(3)(4)(5)(6). Yet other such studies have found no effect of brassica intake on cancer risk (7)(8)(9)(10). ...
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Introduction: Preclinical studies suggest that brassica vegetable diets decrease cancer risk, but epidemiological studies show varied effects, resulting in uncertainty about any health impact of brassicas. Factors controlling absorption of glucosinolate metabolites may relate to inconsistent results. We reported previously that subjects with BMI > 26 kg/m2 (HiBMI), given cooked broccoli plus raw daikon radish (as a source of plant myrosinase) daily for 17 days, had lower glucosinolate metabolite absorption than subjects given a single broccoli meal. This difference was not seen in subjects with BMI < 26 kg/m2 (LoBMI). Our objective in this current study was to determine whether a similar response occurred when cooked broccoli was consumed without a source of plant myrosinase. Methods: In a randomized crossover study (n = 18), subjects consumed no broccoli for 16 days or the same diet with 200 g of cooked broccoli daily for 15 days and 100 g of broccoli on day 16. On day 17, all subjects consumed 200 g of cooked broccoli. Plasma and urine were collected for 24 h and analyzed for glucosinolate metabolites by LC-MS. Results: There was no effect of diet alone or interaction of diet with BMI. However, absorption doubled in HiBMI subjects (AUC 219%, plasma mass of metabolites 202% compared to values for LoBMI subjects) and time to peak plasma metabolite values and 24-h urinary metabolites also increased, to 127 and 177% of LoBMI values, respectively. Conclusion: BMI impacts absorption and metabolism of glucosinolates from cooked broccoli, and this association must be further elucidated for more efficacious dietary recommendations. Clinical Trial Registration: This trial was registered at clinicaltrials.gov (NCT03013465).
... While some diets, such as high-fat diet, red meats, and dairy products, may play a role as DNA damage-causing carcinogens in prostate cancer [3], vegetarian diet is advocated as an important source of cancer-inhibiting bioactive polyphenols [4,5]. Numerous cohort and case-control studies support a notion that consumption of certain diets is associated with a decreased risk of prostate cancer [6][7][8][9]. Recognition of the importance of dietary polyphenols in cancer development and progression has promoted research in not only cancer chemoprevention, but also in tumor recurrence risk reduction, due to the ability of polyphenols to potentiate chemo or/and radiotherapy [10][11][12]. Therefore, more often, polyphenols are considered for cancer interception and therapy, since potential structural modifications, ...
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Natural stilbenes have gained significant attention in the scientific community owing to their potential anticancer effects against prostate cancer. We recently reported that Gnetin C, a resveratrol (Res) dimer, demonstrated more potent inhibition of metastasis-associated protein 1/v-ets avian erythroblastosis virus E26 oncogene homolog 2 (MTA1/ETS2) axis in prostate cancer cell lines than other stilbenes. In this study, we investigated in vivo antitumor effects of Gnetin C in two doses (50 and 25 mg/kg, i.p.) using PC3M-Luc subcutaneous xenografts and compared these to Res and pterostilbene (Pter). We found that while vehicle-treated mice revealed rapid tumor progression, compounds-treated mice showed noticeable delay in tumor growth. Gnetin C in 50 mg/kg dose demonstrated the most potent tumor inhibitory effects. Gnetin C in 25 mg/kg dose exhibited tumor inhibitory effects comparable with Pter in 50 mg/kg dose. Consistent with the effective antitumor effects, Gnetin C-treated tumors showed reduced mitotic activity and angiogenesis and a significant increase in apoptosis compared to all the other groups. The data suggest that Gnetin C is more potent in slowing tumor progression in prostate cancer xenografts than Res or Pter. Taken together, we demonstrated, for the first time, that Gnetin C is a lead compound among stilbenes for effectively blocking prostate cancer progression in vivo.
... According to recent epidemiological research, certain types of cancer are less likely to develop when the dietary intake of cruciferous vegetables is high, providing support for the classification of these vegetables as functional foods. [48][49][50][51][52]. Consequently, the market has been inundated with dietary supplements that contain different extracts or compounds derived from cruciferous vegetables. ...
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Cruciferous vegetables are characterized by the presence of sulfur-containing secondary plant metabolites known as glucosinolates (GLS). The consumption of cruciferous vegetables such as broccoli, cabbage, rocket salad, and cauliflower has been related to the prevention of non-communicable diseases. Their beneficial effects are attributed to the enzymatic degradation products of GLS, e.g., isothiocyanates and indoles. Owing to these properties, there has been a shift in the last few years towards the research of these compounds and a wide range of methods for their extraction and analytical determination have been developed. The aim of this review is to present the sample preparation and extraction procedures of isothiocyanates and indoles from cruciferous vegetables and the analytical methods for their determination. The majority of the references that have been reviewed are from the last decade. Although efforts towards the application of eco-friendly non-conventional extraction methods have been made, the use of conventional solvent extraction is mainly applied. The major analytical techniques employed for the qualitative and quantitative analysis of isothiocyanates and indoles are high-performance liquid chromatography and gas chromatography coupled with or without mass spectrometry detection. Nevertheless, the analytical determination of isothiocyanates presents several problems due to their instability and the absence of chromophores, making the simultaneous determination of isothiocyanates and indoles a challenging task.
... Cruciferous vegetables include arugula (rocket), bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, daikon, horseradish, kale, kohlrabi, radish, turnips, wasabi, and watercress and are commonly consumed globally (International Agency for Research on Cancer, 2004). A number of epidemiological studies have investigated the health impact of cruciferous vegetables in humans and indicated that higher intakes of these vegetables are associated with a reduced risk of cardiometabolic diseases, musculoskeletal conditions, and cancer (Zhang et al., 2011;Liu et al., 2012;Wang et al., 2016;Aune et al., 2017;Blekkenhorst et al., 2017a;Sim et al., 2018). Although these vegetables contain a range of nutrients known to have beneficial health properties, studies have focused on the health effects of glucosinolates that are found almost exclusively in cruciferous vegetables. ...
Article
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An increasing body of evidence highlights the strong potential for a diet rich in fruit and vegetables to delay, and often prevent, the onset of chronic diseases, including cardiometabolic, neurological, and musculoskeletal conditions, and certain cancers. A possible protective component, glucosinolates, which are phytochemicals found almost exclusively in cruciferous vegetables, have been identified from preclinical and clinical studies. Current research suggests that glucosinolates (and isothiocyanates) act via several mechanisms, ultimately exhibiting anti-inflammatory, antioxidant, and chemo-protective effects. This review summarizes the current knowledge surrounding cruciferous vegetables and their glucosinolates in relation to the specified health conditions. Although there is evidence that consumption of a high glucosinolate diet is linked with reduced incidence of chronic diseases, future large-scale placebo-controlled human trials including standardized glucosinolate supplements are needed.
... The study showed that the total cancer risk was inversely associated with cruciferous vegetables (RR = 0.88) and green leafy vegetables (RR = 0.84) intake. In particular, the risk of prostate cancer was found to be staggeringly decreased with the intake of cruciferous vegetables [5][6][7]. The same tendency was also presented in hazard ratios (HR) for lung cancer in a previous paper [8]. ...
Article
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Green-colored foods, such as broccoli, sprouts, soybean, and green leafy vegetables are considered one of the representative healthy foods for containing various functional ingredients that can combat chronic diseases, including diabetes, obesity, and cancer. Herein, we reviewed the anti-cancer activities and the underlying mechanisms of some important bioactive compounds, such as sulforaphane, catechins, chlorophyll, isoflavone, indole dervatives, and lutein, present in green-colored foods. In vivo and clinical studies suggest that sulforaphane, a sulfur-containing compound found in cruciferous vegetables, can ameliorate prostate and breast cancer symptoms by arresting cell-cycle progression and modulating Ki67 and HDAC expression. A green tea compound, known as epigallocatechin-3-gallate (EGCG), has shown remarkable anti-cancer effects against prostate cancer and lung adenocarcinoma in human trials through its antioxidative defense and immunomodulatory functions. Chlorophyll, a natural pigment found in all green plants, can regulate multiple cancer-related genes, including cyclin D1, CYP1A, CYP1B1, and p53. Epidemiological studies indicate that chlorophyll can substantially reduce aflatoxin level and can mitigate colon cancer in human subjects. Remarkably, the consumption of soy isoflavone has been found to be associated with the lower incidence and mortality of breast and prostate cancers in East Asia and in Canada. In vivo and in vitro data point out that isoflavone has modulatory effects on estrogen and androgen signaling pathways and the expression of MAPK, NfκB, Bcl-2, and PI3K/AKT in different cancer models. Other green food bioactive compounds, such as indole derivatives and lutein, also exhibited suppressing effects in rodent models of lung, liver, stomach, cervical, and prostate cancers. In addition, some micronutrients, such as folate, riboflavin, retinoic acid, and vitamin D3 present in green foods, also showed potential cancer suppressing effects. Taken together, these data suggest potential chemopreventive functions of the bioactive compounds from green-colored foods. This paper could be beneficial for further research on the anti-carcinogenic effects of green-colored food-derived compounds, in order to develop green chemotherapeutics for cancers.
... Some ITCs are volatile and become hydrolyzed at higher cooking temperatures (12,13). Previous epidemiological studies have indicated that CVs are inversely associated with several health outcomes including cardiovascular disease (14), type 2 diabetes mellitus (15), gastrointestinal cancer (16,17), breast cancer (18), and reproductive cancers (19,20). Several epidemiological studies have also shown that ITCs might be associated with various cancers (21)(22)(23), diabetes (24,25), and cardiovascular disease (26,27). ...
Article
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Background: The associations of the consumption of cruciferous vegetables (CVs) and their bioactive components, isothiocyanates (ITCs), with ovarian cancer (OC) mortality have been unclear, owing to limited studies and inconsistent findings. To date, no studies have evaluated these associations among Chinese patients with OC. This study aims to provide more evidence indicating the relationships of pre-diagnosis CVs and ITC intake with OC survival. Methods: We examined the associations of pre-diagnosis CV and ITC intake with OC mortality in a hospital-based cohort ( n = 853) of Chinese patients with epithelial OC between 2015 and 2020. Pre-diagnosis dietary information was evaluated with a validated food frequency questionnaire. Deaths were ascertained until March 31, 2021 via medical records and active follow-up. The associations were examined with the Cox proportional hazards model, adjusted for potential confounders, and stratified by menopausal status, residual lesions, histological type, and body mass index (BMI). Results: During a median follow-up of 37.2 months (interquartile: 24.7–50.2 months), we observed 130 deaths. The highest tertile of total CV intake was associated with better survival than the lowest tertile intake [hazard ratio (HR) = 0.57, 95% confidence interval (CI) = 0.33–0.98, p trend < 0.05]. In addition, higher intake of ITCs from CVs was associated with better survival (HR T3VS.T1 = 0.59, 95% CI = 0.36–0.99, p trend = 0.06). Significant inverse associations were also observed for subgroup analyses stratified by menopausal status, residual lesions, histological type, and BMI, although not all associations showed statistical significance. Conclusion: Increasing pre-diagnosis consumption of CVs and ITCs was strongly associated with better survival in patients with OC.
... Based on promising pre-clinical data, cruciferous vegetables have emerged as a dietary substance that might also protect against cancer. Various studies, including: cross-sectional, case control, cohort, and prospective studies, also suggest that consumption of cruciferous vegetables may protect against development of several cancers, including: breast, lung, pancreatic, and prostate cancer [4][5][6][7][8]. ...
Article
Background: Abundant pre-clinical data suggest that consumption of cruciferous vegetables might protect against bladder cancer. While small-scale clinical evidence supports this hypothesis, population-level data is lacking. We tested the hypothesis that consumption of cruciferous vegetables is associated with a lower risk of bladder cancer in a large population-based study. Methods: We investigated the association between dietary consumption of cruciferous vegetables and the risk of bladder cancer in the NIH-American Association of Retired Persons (AARP) Diet and Health Study. Diet at baseline was collected with self-administered food-frequency questionnaires. Bladder cancer diagnoses were identified through linkage with state cancer registries. Hazard ratio (HR) and 95% confidence intervals (CI) were estimated with Cox proportional hazards models. Results: Our analysis included 515,628 individuals. Higher intake of cruciferous vegetables, both overall and when stratified by variety (broccoli vs. brussels sprouts vs. cauliflower), were not associated with bladder cancer risk for men or women. A history of smoking did not affect the results. Conclusions: Our study shows no association between dietary consumption of cruciferous vegetables and incident bladder cancer.
... In some years back, epidemiological analysis shows that diets containing Brassica crops are allied to lower different kind of risk related to cancer (Liu et al. 2012;Liu and Lv, 2013). Brassicaceae are edible that either whole, seed, leaves or stem are used up as source of nutrition as shown in table 1. ...
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Environmental contamination by heavy metals is progressively increasing with increase in population and human activities such as agriculture, industrialization amongst others. Scarcity of land for farm practice lead to cultivating crops and other freshly edible plants in contaminated environment. Plant interacts with heavy metals in various process to become adopted and acclimatized by phytoremediation (i.e. phytoextraction) process. Brassicaceae biosorbs heavy metals and translocate to their edible parts including leaves to which prolong exposure lead to its death. Human and other animals come in contact with heavy metals indirectly through their food chain and web by the consuming those plants products. Heavy metals have detrimental effects in human and animals where inhibition of some enzymes activities, protein misfolding, DNA damages and lipid peroxidation ensues. Trace metals are testified to influence signaling process and related factors causing apoptosis. Therefore, heavy metals are one of the salience death causing of human through food poisonings
... Since the early 1990s, a large body of epidemiological evidence and experimental data have linked the consumption of Brassica vegetables with chemoprotective effects against various types of cancers, including lung (Lam et al. 2009), gastric (Wu et al. 2013), colorectal (Tse & Eslick 2014), breast (Liu & Lv 2013), bladder (Al-Zalabani et al. 2016), and prostate (Liu et al. 2012) cancer. In addition, consumption of Brassica vegetables has also been shown to decrease oxidative stress and protect against cardiovascular disease, neurodegeneration, diabetes, and several inflammatory disorders (Dinkova-Kostova & Kostov 2012, Possenti et al. 2016, Traka 2016. ...
Article
Glucosinolates (GSLs) are a class of sulfur-containing compounds found predominantly in the genus Brassica of the Brassicaceae family. Certain edible plants in Brassica, known as Brassica vegetables, are among the most commonly consumed vegetables in the world. Over the last three decades, mounting evidence has suggested an inverse association between consumption of Brassica vegetables and the risk of various types of cancer. The biological activities of Brassica vegetables have been largely attributed to the hydrolytic products of GSLs. GSLs can be hydrolyzed by enzymes; thermal or chemical degradation also breaks down GSLs. There is considerable variation of GSLs in Brassica spp., which are caused by genetic and environmental factors. Most Brassica vegetables are consumed after cooking; common cooking methods have a complex influence on the levels of GSLs. The variation of GSLs in Brassica vegetables and the influence of cooking and processing methods ultimately affect their intake and health-promoting properties. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 12 is March 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... [8][9][10] An inverse association between high intake of vegetables and/or fruits and incidences of cancer was reported by a number of epidemiological studies. [11][12][13][14][15][16][17] Further, the preventive effect on prostate cancer risk was found for a diet, which was rich in tomato products and lycopene. [18] Unfortunately, there are conflicting findings on the lycopene-prostate cancer risk relationship and the preventive role of tomato products. ...
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Aim: The study investigated the effect of papaya seeds on prostate cancer (PC) using PC-3 cell line because papaya seeds have effects on the male reproductive system notably decreasing sperm concentration, motility, and viability, leading to azoospermia after short-to-long-term treatment. Methods: The black seeds from yellow (ripe) papaya and white seeds from green (unripe) papaya were harvested and then extracted in water, 80% methanol, and hexane. The cytotoxic effects of seeds extracts were determined using a WST-1 proliferation assay. The amount of total polyphenols was determined using Folin Ciocalteu reagent. Results: The methanol extracts from black seeds significantly (P < 0.05) decreased cell proliferation of PC-3 cells whereas hexane- and water-extracts have no effect. However, the water-extract from white seeds stimulated PC cell proliferation. The black seeds contained significantly more polyphenols than that of white seeds. The data suggest that black seeds from papaya have anticancer effects on PCs whereas white seeds stimulated prostate cancer proliferation. The anticancer effect of black seeds may be because of their high concentration of polyphenols. Conclusion: The black seeds from papaya may have a potential to reduce growth of prostate cells; however, consumption of white seeds should be avoided as they may stimulate pre-existing prostate cancer.
... The concentration of these compounds may differ between fruits and vegetables, with fruits typically containing more dietary sugars, and vegetables more protein and fibre [6]. Although certain types of fruits or vegetables may be particularly beneficial for particular health outcomesfor example, cruciferous vegetables may reduce the risk of a number of specific cancers [7][8][9] intake of both fruits and vegetables is recommended to promote good health [10]. ...
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Background The overarching objective was to examine the effectiveness of intervention strategies to promote fruit and vegetable consumption. To do this, systematic review evidence regarding the effects of intervention strategies was synthesized; organized, where appropriate, by the setting in which the strategies were implemented. Additionally, we sought to describe gaps in the review of evidence; that is, where evidence regarding the effectiveness of recommended policy actions had not been systematically synthesised. Methods We undertook a systematic search of electronic databases and the grey literature to identify systematic reviews describing the effects of any intervention strategy targeting fruit and/or vegetable intake in children or adults of any age. Results The effects of 32 intervention strategies were synthesised from the 19 included reviews. The strategies were mapped across all three broad domains of the NOURISHING framework (i.e. food environment, food system and behaviour change communication), but covered just 14 of the framework’s 65 sub-policy areas. There was evidence supporting the effectiveness of 19 of the 32 intervention strategies. The findings of the umbrella review suggest that intervention strategies implemented within schools, childcare services, homes, workplaces and primary care can be effective, as can eHealth strategies, mass media campaigns, household food production strategies and fiscal interventions. Conclusions A range of effective strategy options are available for policy makers and practitioners interested in improving fruit and/or vegetable intake. However, the effects of many strategies – particularly those targeting agricultural production practices, the supply chain and the broader food system – have not been reported in systematic reviews. Primary studies assessing the effects of these strategies, and the inclusion of such studies in systematic reviews, are needed to better inform national and international efforts to improve public health nutrition. Trial registration The review protocol was deposited in a publicly available Open Science framework prior to execution of the search strategy. https://osf.io/unj7x/.
... Anthocyanins are pigments that accumulate in plant vacuoles and have powerful antioxidant activities [14,15]. The hydrolytic products of GLs have multiple functions, such as cancer chemoprevention [16][17][18][19][20][21][22], antibacterial, anti-corrosion [23], and moderating neuropathic pain [24]. The intake of minerals also helps maintaining human body health. ...
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Brassicaceae baby-leaves are good source of functional phytochemicals. To investigate how Chinese kale and pak-choi baby-leaves in response to different wavebands of blue (430 nm and 465 nm) and UV-A (380 nm and 400 nm) LED, the plant growth, glucosinolates, antioxidants, and minerals were determined. Both agronomy traits and phytochemical contents were significantly affected. Blue and UV-A light played a predominant role in increasing the plant biomass and morphology, as well as the contents of antioxidant compounds (vitamin C, vitamin E, phenolics, and individual flavonols), the antioxidant activity (DPPH and FRAP), and the total glucosinolates accumulation. In particular, four light wavebands significantly decreased the content of progoitrin, while 400 nm UV-A light and 430 nm blue light were efficient in elevating the contents of sinigrin and glucobrassicin in Chinese kale. Meanwhile, 400 nm UV-A light was able to increase the contents of glucoraphanin, sinigrin, and glucobrassicin in pak-choi. From the global view of heatmap, blue lights were more efficient in increasing the yield and phytochemical levels of two baby-leaves.
... Kale comprises bioactive compounds such as glucosinolates, carotenoids, polyphenols, glucosinolates, and hydrolysis products and vitamins C and E, which exhibit antioxidant activity [16,19]. A series of meta-analyses have linked the use of Brassica vegetables with the reduced incidence of several types of reproductive system cancers and other malignancies [16,20,21]. Radošević et al. [19] evaluated the anti-tumor activities of B. oleracea from italica and acephala groups on two human tumor cell lines, including HeLa and MCF-7. ...
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Background Brassica oleracea var. acephala is a good source of health-promoting biologically active compounds like phenolics, vitamins, and glucosinolates. Methods and results This in vitro research was conducted to evaluate the apoptotic, antioxidant, anti-inflammatory, and antiproliferative properties of ethanolic extract of Brassica oleracea var. acephala (EEBO) in PC3 prostate cancer cells. The LC–MS/MS technique was applied to identify the biomolecules of EEBO. The MTT assay was used to evaluate the cytotoxic effects of EEBO on PC3 cells. Moreover, qRT-PCR was used to examine the expression levels of Nrf2, NQO1, HO-1, NF-κB, TNF-α, IL-6, BAX, and BCL-2 in PC3 cell line. MMP was predicted by Rhodamine 123 staining, and release of cytochrome c was detected by an ELISA kit. Further, apoptosis was quantified by DNA fragmentation assay. The Western blotting method was used to detect the protein expression levels, and The DPPH assay was applied to determine the antioxidant effect of EEBO. The formula and structure of 19 biomolecules were predicted by LC–MS/MS. EEBO exhibited scavenging activity for DPPH. The MTT test showed EEBO reduced the viability of PC3 cells. The mRNA and protein levels of NRF2 pathway genes and BAX were increased, but those of the NF-κB pathway genes and BCL-2 were decreased in the EEBO-treated cells. Moreover, EEBO led to the diminution of MMP and enhanced the release of cytochrome c and DNA fragmentation, which resulted in apoptosis. Conclusions Molecular changes due to the anticancer impact of EEBO on PC3 were involved in the induction of Nrf2 antioxidant pathway and apoptosis and inhibition of inflammation. Graphical abstract
... Cancer is the second leading cause of death in the United States and high cruciferous vegetable consumption has been associated with lower risk of breast, prostate, lung, colorectal, bladder, endometrial, gastric, ovarian, renal, and pancreatic cancer (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Cruciferous vegetable consumption offers a possible cost-effective and appealing non-pharmacological approach to cancer prevention through dietary intervention. ...
Article
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Robust evidence shows that phytochemicals from cruciferous vegetables, like broccoli, are associated with numerous health benefits. The anti-cancer properties of these foods are attributed to bioactive isothiocyanates (ITCs) and indoles, phytochemicals generated from biological precursor compounds called glucosinolates. ITCs, and particularly sulforaphane (SFN), are of intense interest as they block the initiation, and suppress the progression of cancer, through genetic and epigenetic mechanisms. The efficacy of these compounds is well-demonstrated in cell culture and animal models, however, high levels of inter-individual variation in absorption and excretion of ITCs is a significant barrier to the use of dietary glucosinolates to prevent and treat disease. The source of inter-individual ITC variation has yet to be fully elucidated and the gut microbiome may play a key role. This review highlights evidence that the gut microbiome influences the metabolic fate and activity of ITCs. Human feeding trials have shown inter-individual variations in gut microbiome composition coincides with variations in ITC absorption and excretion, and some bacteria produce ITCs from glucosinolates. Additionally, consumption of cruciferous vegetables can alter the composition of the gut microbiome and shift the physiochemical environment of the gut lumen, influencing the production of phytochemicals. Microbiome and diet induced changes to ITC metabolism may lead to the decrease of cancer fighting phytochemicals such as SFN and increase the production of biologically inert ones like SFN-nitrile. We conclude by offering perspective on the use of novel “omics” technologies to elucidate the interplay of the gut microbiome and ITC formation.
Article
Epidemiological studies evaluating the associations between the consumption of cruciferous vegetables (CV) and diverse health outcomes have generated inconsistent findings.
Article
Isothiocyanates, bioactive phytochemicals of cruciferous vegetables, have chemopreventative efficacy. To clarify evidence of associations between cruciferous vegetable and isothiocyanate intake and various health outcomes, we conducted an umbrella review of meta-analyses and systematic reviews in humans. A total of 413 articles were identified, and 57 articles with 24 health outcomes were included. Consumption of cruciferous vegetables was associated with a reduced risk of all-cause mortality, cancers, and depression. Dose-response analyses revealed that a per 100 g/d increment was associated with a 10% decrease in the risk of all-cause mortality. Warfarin resistance caused by vitamin K-rich broccoli was reported. Caution was warranted for those allergies/hypersensitivities to the Brassica genus. The intake of cruciferous vegetables is generally safe and beneficial in humans. However the quality of the majority (68%) of evidence was low.
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Objectives Interventions designed to improve men’s diet and physical activity (PA) have been recommended as methods of cancer prevention. However, little is known about specific factors that support men’s adherence to these health behaviour changes, which could inform theory-led diet and PA interventions. We aimed to explore these factors in men following prostatectomy for prostate cancer (PCa). Design, setting and participants A qualitative study using semistructured interviews with men, who made changes to their diet and/or PA as part of a factorial randomised controlled trial conducted at a single hospital in South West England. Participants were 17 men aged 66 years, diagnosed with localised PCa and underwent prostatectomy. Interview transcripts underwent thematic analysis. Results Men were ambivalent about the relationship of nutrition and PA with PCa risk. They believed their diet and level of PA were reasonable before being randomised to their interventions. Men identified several barriers and facilitators to performing these new behaviours. Barriers included tolerance to dietary changes, PA limitations and external obstacles. Facilitators included partner involvement in diet, habit formation and brisk walking as an individual activity. Men discussed positive effects associated with brisk walking, such as feeling healthier, but not with nutrition interventions. Conclusions The facilitators to behaviour change suggest that adherence to trial interventions can be supported using well-established behaviour change models. Future studies may benefit from theory-based interventions to support adherence to diet and PA behaviour changes in men diagnosed with PCa.
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Background: Dietary patterns rich in fruits and vegetables are considered to reduce atherosclerotic disease presentation and are reported to be inversely associated with subclinical measures of atherosclerosis, such as carotid artery intima-media thickness (IMT) and plaque. However, the effect of vegetable intake alone, and relationships to specific types of vegetables containing different phytochemical profiles, is important. The aim of this study was to investigate the associations of total vegetable intake and specific vegetables grouped according to phytochemical constituents with common carotid artery IMT (CCA-IMT) and carotid plaque severity in a cohort of older adult women (aged ≥70 years). Methods and results: Total vegetable intake was calculated at baseline (1998) using a validated food frequency questionnaire. Vegetable types included cruciferous, allium, yellow/orange/red, leafy green, and legumes. In 2001, CCA-IMT (n=954) and carotid focal plaque (n=968) were assessed using high-resolution B-mode carotid ultrasonography. Mean (SD) total vegetable intake was 199.9 (78.0) g/d. Women consuming ≥3 servings of vegetables each day had ≈4.6% to 5.0% lower mean CCA-IMT (P=0.014) and maximum CCA-IMT (P=0.004) compared with participants consuming <2 servings of vegetables. For each 10 g/d higher in cruciferous vegetable intake, there was an associated 0.006 mm (0.8%) lower mean CCA-IMT (P<0.01) and 0.007 mm (0.8%) lower maximum CCA-IMT (P<0.01). Other vegetable types were not associated with CCA-IMT (P>0.05). No associations were observed between vegetables and plaque severity (P>0.05). Conclusions: Increasing vegetables in the diet with a focus on consuming cruciferous vegetables may have benefits for the prevention of subclinical atherosclerosis in older adult women. Clinical trial registration: URL: http://www.anzctr.org.au. Unique identifier: ACTRN12615000750583.
Article
There is growing evidence that cancer chemoprevention employing natural, bioactive compounds may halt or at least slow down the different stages of carcinogenesis. A particularly advantageous effect is attributed to derivatives of sulfur-organic phytochemicals, such as glucosinolates (GLs) synthesized mainly in Brassicaceae plant family. GLs are hydrolysed enzymatically to bioactive isothiocyanates (ITC) and indoles, which exhibit strong anti-inflammatory and anti-carcinogenic activity. Highly bioavailable electrophilic ITC are of particular interest, as they can react with nucleophilic groups of important biomolecules to form dithiocarbamates, thiocarbamates and thioureas. These modifications seem responsible for chemopreventive activity, but also for genotoxicity and mutagenicity. It was documented that ITC can permanently bind to important biomolecules such as glutathione, cytoskeleton proteins, transcription factors NF-κB and Nrf2, thiol-disulfide oxidoreductases, proteasome proteins or heat shock proteins. Furthermore, ITC may also affect epigenetic regulation of gene expression, e.g. by inhibition of histone deacetylases. Some other derivatives of glucosinolates, especially indoles, are able to form covalent bonds with nucleobases in DNA, which may result in genotoxicity and mutagenicity. This article summarizes the current state of knowledge about glucosinolates and their degradation products in terms of possible interactions with reactive groups of cellular molecules.
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Sulforaphane belongs to the active class of isothiocyanates capable of delivering various biological benefits for health promotion and disease prevention. This compound is considered vital to curtail numerous metabolic disorders. Various studies have proven its beneficial effects against cancer prevention and its possible utilization as a therapeutic agent in cancer treatment. Understanding the mechanistic pathways and possible interactions at cellular and subcellular levels is key to design and develop cancer therapeutics for humans. In this respect, a number of mechanisms such as modulation of carcinogen metabolism & phase II enzymatic activities, cell cycle arrest, activation of Nrf2, cytotoxic, proapoptotic and apoptotic pathways have been reported to be involved in cancer prevention. This article provides sufficient information by critical analysis to understand the mechanisms involved in cancer prevention attributed to sulforaphane. Furthermore, various clinical studies have also been included for design and development of novel therapies for cancer prevention and cure. Practical applications Diet and dietary components are potential tools to address various lifestyle-related disorders. Due to plenty of environmental and cellular toxicants, the chances of cancer prevalence are quite large which are worsen by adopting unhealthy lifestyles. Cancer can be treated with various therapies but those are acquiring side effects causing the patients to suffer the treatment regime. Nutraceuticals and functional foods provide safer options to prevent or delay the onset of cancer. In this regard, sulforaphane is a pivotal compound to be targeted as a potential agent for cancer treatment both in preventive and therapeutic regimes. This article provides sufficient evidence via discussing the underlying mechanisms of positive effects of sulforaphane to further the research for developing anticancer drugs that will help assuage this lethal morbidity.
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Scope: Observational studies have associated consumption of cruciferous vegetables with reduced risk of prostate cancer. This effect has been associated with the degradation products of glucosinolates - thioglycosides that accumulate within crucifers. The possible role of S-methyl cysteine sulfoxide, a metabolite that also accumulates in cruciferous vegetables, and its derivatives, in cancer prevention is relatively unexplored compared to glucosinolate derivatives. We test the hypothesis that consuming a broccoli soup results in the accumulation of sulfate (a SMCSO derivative) and other broccoli-derived metabolites in prostate tissue. Methods and results: Eighteen men scheduled for transperineal prostate biopsy were recruited into a four-week parallel single blinded diet supplementation study (NCT02821728). Nine men supplemented their diet with three 300 ml portions of a broccoli soup each week for four weeks prior to surgery. Analyses of prostate biopsy tissues revealed no detectable levels of glucosinolates and derivatives. In contrast, SMCSO was detected in prostate tissues of the participants, with significantly higher levels in tissue of men in the supplementation arm. SMCSO was also found in blood and urine samples from a previous intervention study with the identical broccoli soup. Conclusion: The consequences of SMCSO accumulation in prostate tissues and its potential role in prevention of prostate cancer remains to be investigated. This article is protected by copyright. All rights reserved.
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With the expansion of the area under Cruciferae vegetable cultivation, and an increase in the incidence of natural threats such as pests and diseases globally, Cruciferae vegetable losses caused by pathogens, insects, and pests are on the rise. As one of the key metabolites produced by Cruciferae vegetables, glucosinolate (GLS) is not only an indicator of their quality but also controls infestation by numerous fungi, bacteria, aphids, and worms. Today, the safe and pollution-free production of vegetables is advocated globally, and environmentally friendly pest and disease control strategies, such as biological control, to minimize the adverse impacts of pathogen and insect pest stress on Cruciferae vegetables, have attracted the attention of researchers. This review explores the mechanisms via which GLS acts as a defensive substance, participates in responses to biotic stress, and enhances plant tolerance to the various stress factors. According to the current research status, future research directions are also proposed.
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Emerging epidemiological studies have assessed the potential relationship between the inflammatory potential of diet measured using the dietary inflammatory index (DII) and the risk of prostate cancer and found inconsistent results. The aim of this study was to systematically evaluate this issue using a meta-analysis approach. A comprehensive literature search of papers published through March 2019 was performed in the PubMed and EMBASE databases. The summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a DerSimonian and Laird random effects model. A categorized analysis and linear and nonlinear dose-response analyses were performed. Ten studies met the inclusion criteria for our meta-analysis. The highest DII score category was associated with a significantly higher risk of prostate cancer than the lowest DII score category (OR = 1.73, 95% CI 1.34–2.23). In the dose-response analysis, the summary OR of prostate cancer for an increment of one unit of the DII was 1.10 (95% CI 1.04–1.17). The sensitivity analysis indicated that exclusion of any single study did not materially alter the pooled risk estimates. Finally, there was no evidence of significant publication bias with Begg’s test or with Egger’s test. In conclusion, this meta-analysis suggests that an increased DII is related to a higher risk of prostate cancer and that the risk increases by 10.0% per unit of the DII. However, further well-designed prospective trials with larger sample sizes should be performed to validate our preliminary findings.
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Background Drug repurposing enables the discovery of potential cancer treatments using publically available data from over 4000 published Food and Drug Administration approved and experimental drugs. However, the ability to effectively evaluate the drug's efficacy remains a challenge. Impediments to broad applicability include inaccuracies in many of the computational drug‐target algorithms and a lack of clinically relevant biologic modeling systems to validate the computational data for subsequent translation. Methods We have integrated our computational proteochemometric systems network pharmacology platform, DrugGenEx‐Net, with primary, continuous cultures of conditionally reprogrammed (CR) normal and prostate cancer (PCa) cells derived from treatment‐naive patients with primary PCa. Results Using the transcriptomic data from two matched pairs of benign and tumor‐derived CR cells, we constructed drug networks to describe the biological perturbation associated with each prostate cell subtype at multiple levels of biological action. We prioritized the drugs by analyzing these networks for statistical coincidence with the drug action networks originating from known and predicted drug‐protein targets. Prioritized drugs shared between the two patients’ PCa cells included carfilzomib (CFZ), bortezomib (BTZ), sulforaphane, and phenethyl isothiocyanate. The effects of these compounds were then tested in the CR cells, in vitro. We observed that the IC50 values of the normal PCa CR cells for CFZ and BTZ were higher than their matched tumor CR cells. Transcriptomic analysis of CFZ‐treated CR cells revealed that genes involved in cell proliferation, proteases, and downstream targets of serine proteases were inhibited while KLK7 and KLK8 were induced in the tumor‐derived CR cells. Conclusions Given that the drugs in the database are extremely well‐characterized and that the patient‐derived cells are easily scalable for high throughput drug screening, this combined in vitro and in silico approach may significantly advance personalized PCa treatment and for other cancer applications.
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Cruciferous vegetables contain glucosinolates, minor substances that have anti-carcinogenic and detoxifying effects, increasing the adaptive capacity of the body. In case of insufficient consumption of cruciferous with food, some glucosonolates or their derivatives, such as inol‑3-carbinol, can be additionally introduced into the diet. The article discusses the mechanisms of action and the role of indole‑3-carbinol in supporting the reproductive system and adaptive reserves of the body.
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Background: Most of the epidemiological data on prostate cancer risk factors come from high-income countries (HIC). Reducing exposure to prostate cancer modifiable risk factors may significantly lower PCa morbidity and mortality in LIC and MIC. The objective of this study was to summarize the evidence on modifiable risk factors (RFs) for PCa in LIC and lower-middle-income countries (LMIC). Methods: We conducted a systematic search on MEDLINE, EMBASE, and Global Health databases. We selected case-control and cohort studies from 2010 onwards that studied modifiable RFs for PCa in LIC and LMIC with a population of 30 million or more, as defined by the World Bank in January 2021. Risk of bias was assessed by the Ottawa-Newcastle tool. Individual study estimates were pooled when estimates were available for at least two studies. Results: 5740 studies were initially identified; 16 studies met inclusion criteria. All were case-control studies except one retrospective cohort study. Higher fat intake was associated with a higher risk of PCa incidence with an odds ratio (OR) of 3.13 (95% CI 1.33-7.33). Higher vegetable intake (OR 0.48, 95% CI 0.24-0.97) and tea consumption (OR 0.51, 95% CI 0.32-0.83) were associated with a lower risk for PCa. There was no association between fruits, fish, and chicken consumption and risk of PCa. Alcohol consumption, smoking, red meat intake, and a BMI ≥ 25-30 kg/m2 showed a trend towards an increased risk, although these were not statistically significant. Conclusions: In LIC and LMIC, high fat intake was associated with higher risk of PCa while a diet rich in vegetables and tea intake was associated with a lower risk. Future prospective studies will be important to elucidate whether other modifiable risk factors for PCa specific to LIC and LMIC can be identified to inform impactful and cost-effective preventive strategies in these countries.
Preprint
This study reviewed aspects of the biology of two members of the glucosinolate family, namely sinigrin and glucoraphanin and their potential biomedical therapeutic and industrial applications. Sinigrin and glucoraphanin are converted by the -sulphoglucosidase myrosinase or the gut microbiota into their bioactive forms, allyl isothiocyanate (AITC) and sulphoraphanin (SFN) which constitute part of a sophisticated defence mechanism plants have developed over several hundred million years of evolution to protect them from parasitic attack from aphids, ticks and nematodes. These compounds display biological activities in a number of mammalian physiological processes and potential biotherapeutic application. Glucosinolates may be useful in bio-fumigation and treatment of biofilms which occur on plant equipment and medical implants formed by problematic pathogenic bacteria such as Pseudomonas aeruginosa. AITC and SFN display similar antibiotic activity as Vancomycin in the treatment of bacteria listed by the World Health Organization as antibiotic-resistant "priority pathogens".AITC and SFN also display bioactivity in cancer chemoprevention through the induction of phase II antioxidant enzymes which inactivate potential carcinogens. The glucosinolates have found application in the prevention of bacterial and fungal spoilage of food substances during processing and in advanced food packaging formats which improve the shelf-life of food products.
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Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30
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This study was undertaken to determine the chemopreventative efficacy of phenethyl isothiocyanate (PEITC), a bioactive constituent of many edible cruciferous vegetables, in a mouse model of prostate cancer, and to identify potential biomarker(s) associated with PEITC response. The chemopreventative activity of dietary PEITC was investigated in Transgenic Adenocarcinoma of Mouse Prostate mice that were fed a control diet or one containing 3 μmol PEITC/g (n = 21 mice per group) for 19 weeks. Dorsolateral prostate tissue sections were stained with hematoxylin and eosin for histopathologic evaluations and subjected to immunohistochemistry for analysis of cell proliferation (Ki-67 expression), autophagy (p62 and LC3 protein expression), and E-cadherin expression. Autophagosomes were visualized by transmission electron microscopy. Apoptotic bodies were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. Plasma proteomics was performed by two-dimensional gel electrophoresis followed by mass spectrometry to identify potential biomarkers of PEITC activity. All statistical tests were two-sided. Administration of PEITC (3 μmol/g diet) decreased incidence (PEITC diet vs control diet, mean = 21.65 vs 57.58%, difference = -35.93%, 95% confidence interval = -45.48% to -13.10%, P = .04) as well as burden (affected area) (PEITC diet vs control diet, mean = 18.53% vs 45.01%, difference = -26.48%, 95% confidence interval = -49.78% to -3.19%, P = .02) of poorly differentiated tumors in the dorsolateral prostate of transgenic mice compared with control mice, with no toxic effects. PEITC-mediated inhibition of prostate carcinogenesis was associated with induction of autophagy and overexpression of E-cadherin in the dorsolateral prostate. However, PEITC treatment was not associated with a decrease in cellular proliferation, apoptosis induction, or inhibition of neoangiogenesis. Plasma proteomics revealed distinct changes in the expression of several proteins (eg, suppression of clusterin protein) in the PEITC-treated mice compared with control mice. In this transgenic model, dietary PEITC suppressed prostate cancer progression by induction of autophagic cell death. Potential biomarkers to assess the response to PEITC treatment in plasma were identified.
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The present study shows that oral gavage of 6 mumol d,l-sulforaphane (SFN), a synthetic analogue of cruciferous vegetable-derived L isomer, thrice per week beginning at 6 weeks of age, significantly inhibits prostate carcinogenesis and pulmonary metastasis in TRAMP mice without causing any side effects. The incidence of the prostatic intraepithelial neoplasia and well-differentiated (WD) carcinoma were approximately 23% to 28% lower (P < 0.05 compared with control by Mann-Whitney test) in the dorsolateral prostate (DLP) of SFN-treated mice compared with controls, which was not due to the suppression of T-antigen expression. The area occupied by the WD carcinoma was also approximately 44% lower in the DLP of SFN-treated mice relative to that of control mice (P = 0.0011 by Mann Whitney test). Strikingly, the SFN-treated mice exhibited approximately 50% and 63% decrease, respectively, in pulmonary metastasis incidence and multiplicity compared with control mice (P < 0.05 by t test). The DLP from SFN-treated mice showed decreased cellular proliferation and increased apoptosis when compared with that from control mice. Additionally, SFN administration enhanced cytotoxicity of cocultures of natural killer (NK) cells and dendritic cells (DC) against TRAMP-C1 target cells, which correlated with infiltration of T cells in the neoplastic lesions and increased levels of interleukin-12 production by the DC. In conclusion, the results of the present study indicate that SFN administration inhibits prostate cancer progression and pulmonary metastasis in TRAMP mice by reducing cell proliferation and augmenting NK cell lytic activity.
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Over several decades a number of epidemiological studies have identified the inverse associations between cruciferous vegetables and the risk of several cancers, including gastric, breast, colo-rectal, lung, prostate, bladder and endometrial cancers, via plausible physiological mechanisms. Although retrospective case-control studies have consistently reported inverse associations between the risk of these cancers and the intake of cruciferous vegetables and isothiocyanate-containing plants, current prospective cohort studies have found these associations to be weaker and less consistent. Genetic variations affecting the metabolism of glucosinolate hydrolysis products may modulate the effects of cruciferous vegetable consumption on cancer risk, which may be one of the reasons for the discrepancies between retrospective and prospective studies. In addition, methodological issues such as measurement errors of dietary exposure, misclassification, recall bias, publication bias, confounding and study design should be carefully considered in interpreting the results of case-control and cohort studies and in drawing conclusions in relation to the potential effects of cruciferous vegetables on cancers. Although recent comprehensive reviews of numerous studies have purported to show the specific protective role of cruciferous vegetables, and particularly Brassicas, against cancer risk, the current epidemiological evidence suggests that cruciferous vegetable consumption may reduce the risk only of gastric and lung cancers. However, there is at present no conclusive evidence that the consumption of cruciferous vegetables attenuates the risk of all other cancers.
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A cohort of 17,633 white males age 35 and older responded to a mailed epidemiological questionnaire in 1966 and was followed until 1986 to determine the risk of cancer associated with diet, tobacco use, and other factors. During the 20-year follow-up, 149 fatal prostate cancer cases were identified. Relative risks for prostate cancer were significantly elevated among cigarette smokers (relative risk, 1.8; 95% confidence interval, 1.1-2.9) and users of smokeless tobacco (relative risk, 2.1; 95% confidence interval, 1.1-4.1). No significant associations were found with frequency of consumption of meats, dairy products, fruits, or vegetables. There were no overall significant associations between consumption of vitamin A from animal sources (retinol) and provitamin A from plant sources (carotene) and risk, but positive trends were seen for ages under 75, while inverse associations were found at older ages. Beverage consumption, including drinking coffee and alcohol, was unrelated to risk. Marital status, education, rural/urban status, and farming residence were also unrelated to the risk of fatal prostate cancer. The findings add to limited evidence that tobacco may be a risk factor for prostate cancer, but fail to provide clues to dietary or other risk factors.
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Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews. Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution.
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Epidemiological studies recently concluded that consumption of cruciferous vegetables such as broccoli, cabbage, and cauliflower, etc. is inversely related to prostate cancer risk, although the mechanism of prevention and the responsible phytochemicals are unknown. Since clinically significant prostate cancer eventually can grow independent of androgen, the association of the growth and tumorigenesis of such prostate cancer cells with sulforaphane (SFN) which is a predominant isothiocyanate in cruciferous vegetables, investigated. These vegetables contain high concentrations of glucosinolate glucoraphanin, which yield sulforaphane when hydrolyzed by the plant enzyme myrosinase. This study showed that exposure of human androgen-independent DU-145 prostate cancer cells to SFN resulted in the inhibition of growth and tumorigenesis, as revealed by a reduction in cell density, DNA synthesis, and clonogenesis. Analyses of the mechanism revealed that SFN mediated cell cycle arrest by modulating the expression and functions of cell cycle regulators. SFN induced signals that inhibited the activity of cyclin-dependent kinase cdk4 with an up-stream induction of cdk inhibitor p21WAF-1/Cip-1, and reduced cyclin D1. The inhibition of cdk kinase activity could be affected with <1 micro M SFN within 24 h. As a result, phosphorylation of Rb proteins, which activates the transition from G1- to S-phase, was significantly decreased and the cell cycle progression retarded. SFN also down-regulated the expression of bcl-2, a suppressor of apoptosis, and activated caspases to execute apoptosis in the prostate cancer cells. The regulators of cell cycle have thus been revealed as targets of sulforaphane for growth arrest and apoptosis induction. The potential of SFN, as an active dietary factor to inhibit initiation and post-initiation of prostate cancer carcinogenesis is discussed.
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Prostate cancer usually progresses to androgen refractory after an initial anti-androgen treatment. The androgen receptor (AR) is a pivotal factor for the androgen-mediated growth and maintenance of the prostate. Abnormality of the AR, such as overexpression has been postulated to be related to the hormone independent growth of the cancer. Although we previously demonstrated that the AR expression could be modulated by isothiocyanates, which are natural constituents of cruciferous vegetables, the mechanism, however, remained to be clarified. We have since investigated the mechanism of phenethyl isothiocyanate (PEITC) in AR regulation. A human androgen dependent prostate cancer cell line LNCaP (AD) and its sub-line LNCaP (AI), i.e. androgen independent but overexpressing AR, were exposed to PEITC. The effects of PEITC on cell growth and AR expression/transcription were analyzed with MTT assay, real-time PCR and western blotting. The AR promoter activity was analyzed with the reporter activity after transfection with pAR-luc. The effects on Sp1, the major transcription factor of the AR, were tested with Sp1-luc activity, western blotting and electrophoretic mobility shift assay. PEITC induced a significant growth inhibition, with equal IC(50), in both AD and AI cells. The AR present in both cells was repressed as demonstrated with real-time PCR and western blot. PEITC mediates dual effects at transcriptional and post-translational levels to regulate the AR. At transcriptional level the AR level was reduced via inhibition of the transcription factor Sp1, and at post-translational level by accelerating protein degradation. PEITC represses AR transcription and expression, and mediates growth arrest in androgen dependent and independent prostate cancer cells. With the AR modulation and growth attenuation, PEITC and possibly other isothiocyanates, may prevent and inhibit hormone sensitive and refractory prostate cancer.
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Our aim was to review the epidemiological literature on possible cancer-preventive effects of the consumption of fruits and vegetables in humans, to quantify the effect of high versus low consumption of fruits and vegetables, and to give an overall assessment of the existing evidence. We based our work on an expert meeting conducted by the International Agency for Research on Cancer in 2003. A qualitative reading and evaluation of relevant articles on the cancer-preventive effect of the consumption of fruits and vegetables was made followed by the calculation of the mean relative risk and range for cohort and case-control studies separately. The possible population-preventable fraction for modifying diet in relation to fruit and vegetable consumption was calculated as well as an overall statement about the degree of evidence for the cancer-preventive effect of fruit and vegetable consumption for each cancer site. There is limited evidence for a cancer-preventive effect of the consumption of fruits and vegetables for cancer of the mouth and pharynx, esophagus, stomach, colon-rectum, larynx, lung, ovary (vegetables only), bladder (fruit only), and kidney. There is inadequate evidence for a cancer-preventive effect of the consumption of fruits and vegetables for all other sites. Applying this range of risk difference to the range of prevalence of low intake, the preventable fraction for low fruit and vegetable intake would fall into the range of 5-12%. It is important to recognize that this is only a crude range of estimates and that the proportion of cancers that might be preventable by increasing fruit and vegetable intake may vary beyond this range for specific cancer sites and across different regions of the world.
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Associations between prostate cancer and dietary factors, physical activity and smoking were assessed based on data from a population-based case-control study. The study was conducted among residents of northeastern Ontario. Cases were identified from the Ontario Cancer Registry and diagnosed between 1995 and 1998 at ages 50 to 84 years (N=752). Male controls were identified from telephone listings and were frequency matched to cases on age (N=1,613). Logistic regression analyses investigated history of diet, physical activity and smoking as potential risk factors. Tomato intake had a significant positive association with prostate cancer risk for highest versus lowest quartiles (OR=1.6; 95 percent CI: 1.2-2.0). Associations were observed for tomato or vegetable juices and ketchup (OR=1.5; 95 percent CI: 1.2-1.9; OR=1.2; 95 percent CI: 1.0-1.5, respectively). Neither other dietary variables nor smoking were associated with prostate cancer risk. Strenuous physical activity by men in their early 50s was associated with reduced risk (OR=0.8; 95 percent CI: 0.6-0.9). While the recreational physical activity association was consistent with results from previous studies, the tomato products association was not.
Conference Paper
Epidemiological studies have consistently shown that regular consumption of fruits and vegetables is strongly associated with reduced risk of developing chronic diseases, such as cancer and cardiovascular disease. It is now widely believed that the actions of the antioxidant nutrients alone do not explain the observed health benefits of diets rich in fruits and vegetables, because taken alone, the individual antioxidants studied in clinical trials do not appear to have consistent preventive effects. Work performed by our group and others has shown that fruits and vegetable phytochemical extracts exhibit strong antioxidant and anti proliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. We proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for these potent antioxidant and anticancer activities and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in whole foods. This explains why no single antioxidant can replace the combination of natural phytochemicals in fruits and vegetables to achieve the health benefits. The evidence suggests that antioxidants or bioactive compounds are best acquired through whole-food consumption, not from expensive dietary supplements. We believe that a recommendation that consumers eat 5 to 10 servings of a wide variety of fruits and vegetables daily is an appropriate strategy for significantly reducing the risk of chronic diseases and to meet their nutrient requirements for optimum health.
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This manuscript reviews the epidemiologic evidence that Brassica vegetables are associated with reduced prostate cancer risk. Brassica vegetables, which include broccoli, cabbage, mustard and collard greens, and bok choy, contain glucosinolates, whose metabolic breakdown products are potent modulators of xenobiotic metabolizing enzymes that protect DNA from damage. There are six published studies with clearly interpretable results regarding brassica vegetables and prostate cancer risk. Of these, three reported statistically significant reduced risks (p < 0.05), and one reported a borderline significant reduced risk (p = 0.06) with high Brassica vegetable consumption. The epidemiologic literature provides modest support for the hypothesis that high intakes of Brassica vegetables reduce prostate cancer risk.
Article
Objectives: To evaluate the relationship between prostate cancer and several potential lifestyle risk factors. Methods: We analyzed data obtained from a population-based case–control study conducted in eight Canadian provinces. Risk estimates were generated by applying multivariate logistic regression methods to 1623 histologically confirmed prostate cancer cases and 1623 male controls aged 50–74. Results: Cases were more likely to have a first-degree relative with a history of cancer, particularly prostate cancer (OR = 3.1, 95% CI = 1.8–5.4). Reduced risks of prostate cancer were observed among those of Indian descent (OR = 0.2, 95% CI = 0.1–0.5) or any Asian descent (OR = 0.3, 95% CI = 0.2–0.6) relative to those of western European descent. Total fat consumption, tomato and energy intake, were not associated with prostate cancer. The risk of prostate cancer was inversely related to the number of cigarettes smoked daily (p = 0.06) and cigarette pack-years (p < 0.01), while no association was observed between the total number of smoking years or the number of years since smoking cessation. Anthropometric measures and moderate and strenuous levels of leisure time physical activity were not strongly related to prostate cancer. In contrast, strenuous occupational activities at younger ages appeared protective. Conclusions: Our analyses are limited by the absence of data related to tumor severity and screening history. Further studies are needed to investigate the relationship between behavioral risk factors and prostate cancer screening practices.
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Estimates of the worldwide incidence and mortality from 27 cancers in 2008 have been prepared for 182 countries as part of the GLOBOCAN series published by the International Agency for Research on Cancer. In this article, we present the results for 20 world regions, summarizing the global patterns for the eight most common cancers. Overall, an estimated 12.7 million new cancer cases and 7.6 million cancer deaths occur in 2008, with 56% of new cancer cases and 63% of the cancer deaths occurring in the less developed regions of the world. The most commonly diagnosed cancers worldwide are lung (1.61 million, 12.7% of the total), breast (1.38 million, 10.9%) and colorectal cancers (1.23 million, 9.7%). The most common causes of cancer death are lung cancer (1.38 million, 18.2% of the total), stomach cancer (738,000 deaths, 9.7%) and liver cancer (696,000 deaths, 9.2%). Cancer is neither rare anywhere in the world, nor mainly confined to high-resource countries. Striking differences in the patterns of cancer from region to region are observed.
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3,3'-Diindolylmethane (DIM) is a major in vivo derivative of indole-3-carbinol, which is present in cruciferous vegetables and has been reported to possess anti-carcinogenic properties. In the present study, we examined whether DIM inhibits the development of prostate cancer using the transgenic adenocarcinoma mouse prostate (TRAMP) model. DIM feeding inhibited prostate carcinogenesis in TRAMP mice, reduced the number of cells expressing the SV40 large tumor antigen and proliferating cell nuclear antigen, and increased the number of terminal dUTP nick-end labeling-positive cells in the dorsolateral lobes of the prostate. Additionally, DIM feeding reduced the expression of cyclin A, cyclin-dependent kinase (CDK)2, CDK4, and Bcl-xL, and increased p27 and Bax expression. To assess the mechanisms by which DIM induces apoptosis, LNCaP and DU145 human prostate cancer cells were cultured with various concentrations of DIM. DIM induced a substantial reduction in the numbers of viable cells and induced apoptosis in LNCaP and DU145 cells. DIM increased the cleavage of caspase-9, -7, -3, and poly (ADP-ribose) polymerase (PARP). DIM increased mitochondrial membrane permeability and the translocation of cytochrome c and Smac/Diablo from the mitochondria. Additionally, DIM induced increases in the levels of cleaved caspase-8, truncated Bid, Fas, and Fas ligand, and the caspase-8 inhibitor Z-IETD-FMK was shown to mitigate DIM-induced apoptosis and the cleavage of caspase-3, PARP, and Bid. These results indicate that DIM inhibits prostate carcinogenesis via induction of apoptosis and inhibition of cell cycle progression. DIM induces apoptosis in prostate cancer cells via the mitochondria- and death receptor-mediated pathways.
Article
Cruciferous vegetable consumption is associated with decreased risk of several cancers, including prostate cancer. Gluconasturtiin, one of the predominant glucosinolates in cruciferous vegetables, is hydrolyzed to yield phenylethyl isothiocyanate (PEITC). PEITC absorption and metabolism in humans involves glutathione conjugation followed by conversion via the mercapturic acid pathway to an N-acetylcysteine (NAC) conjugate that is excreted in the urine. We observed an inhibitory effect of PEITC and its metabolite, NAC-PEITC, on cancer cell proliferation, cell-cycle progression, and apoptosis in LNCaP human prostate cancer cells. PEITC and NAC-PEITC suppressed LNCaP cell proliferation in a dose-dependent manner, and exposure to 5 microM PEITC or NAC-PEITC reduced cell proliferation by 25% and 30%, respectively. Cell-cycle analysis revealed that cells treated with 5 microM PEITC or NAC-PEITC arrested at the G(2)/M phase. In addition, the percentage of cells in the S phase decreased from 46% to 25% following 48 h of incubation with PEITC or NAC-PEITC. The G(2)/M-phase cell-cycle arrest of LNCaP cells grown in the presence of PEITC or NAC-PEITC is correlated with the downregulation of Cdk1 and cyclin B(1) protein expression. Apoptosis was observed at the later stages of 24-h and 48-h treatments with 5 microM PEITC and NAC-PEITC. In conclusion, PEITC and NAC-PEITC are potential chemopreventive/chemotherapeutic agents against LNCaP human prostate cancer cells.
Article
Although dietary risk factors may differ between localized and advanced prostate cancer, data on associations between the consumption of fruits and vegetables and risk of localized and advanced cancers are limited. We examined associations between fruit and vegetable consumption and risk of prostate cancer in a Japanese population. During 1995-1998, a validated food frequency questionnaire was administered to 43,475 men aged 45-74 yr. During 321,061 person-years of follow-up until the end of 2004, 339 cases of prostate cancer were identified. Consumption of fruits or total vegetables was not associated with a decreased risk of total prostate cancer, with corresponding multivariate hazard ratios of the highest vs. lowest quartiles of 1.09 (95% CI = 0.77-1.53; trend P = 0.39) for fruits and 1.33 (95% CI = 0.93-1.91; trend P = 0.52) for total vegetables. Also, no association was observed for intake of either fruits or vegetables (total or any subtype) with localized or advanced prostate cancer. This prospective cohort study suggests that consumption of fruits or vegetables may not be associated with the risk of either localized or advanced prostate cancer in Japanese men. However, the possibility of confounding by detection bias on the risk of localized cancer could not be totally ruled out.
Article
High consumption of cruciferous vegetables is associated with a reduced risk of prostate cancer in epidemiological studies. There is preliminary evidence that sulforaphane, derived from glucoraphanin found in a number of crucifers, may prevent and induce regression of prostate cancer and other malignancies in preclinical models, but the mechanisms that may explain these effects are not fully defined. Recent reports show that sulforaphane may impair prostate cancer growth through inhibition of histone deacetylases, which are up-regulated in cancer. Indeed, one of these enzymes, histone deacetylase 6 (HDAC6), influences the acetylation state of a key androgen receptor (AR) chaperone, HSP90. AR is the central signaling pathway in prostate cancer, and its inhibition is used for both prevention and treatment of this disease. However, it is not known whether the effects of sulforaphane involve suppression of AR. We hypothesized that sulforaphane treatment would lead to hyperacetylation of HSP90 and that this would destabilize AR and attenuate AR signaling. We confirmed this by demonstrating that sulforaphane enhances HSP90 acetylation, thereby inhibiting its association with AR. Moreover, AR is subsequently degraded in the proteasome, which leads to reduced AR target gene expression and reduced AR occupancy at its target genes. Finally, sulforaphane inhibits HDAC6 deacetylase activity, and the effects of sulforaphane on AR protein are abrogated by overexpression of HDAC6 and mimicked by HDAC6 siRNA. The inactivation by sulforaphane of HDAC6-mediated HSP90 deacetylation and consequent attenuation of AR signaling represents a newly defined mechanism that may help explain this agent's effects in prostate cancer.
Article
Glucosinolates (GLS) are secondary plant metabolites occurring in cruciferous vegetables. Their biologically active break-down products show cancer preventive properties in animal and cell studies. So far, epidemiologic studies, using consumption of cruciferous vegetables as proxy for GLS intake, yielded inconsistent results. Here, we evaluated the association between dietary intake of GLS in comparison with consumption data of GLS-containing foods and the risk of prostate cancer. The study population comprised 11,405 male participants of the prospective EPIC-Heidelberg cohort study. During a mean follow-up time of 9.4 years, 328 incident cases of prostate cancer occurred. At recruitment, habitual food consumption was assessed by a validated food frequency questionnaire, and intake of individual GLS was estimated by means of a newly compiled database on food content of GLS. Adjusted hazard ratios (HR) for prostate cancer were calculated using the Cox proportional hazard model. Median daily intake of total GLS was 7.9 mg/day (interquartile range 5.1-11.9 mg/day). The risk of prostate cancer decreased significantly over quartiles of total GLS intake (multivariate HR [4th vs. 1st quartile] 0.68, 95% CI 0.48-0.97, p(trend) 0.03). Associations with GLS-containing food intake were weaker. Among GLS subgroups, aliphatic GLS showed the strongest inverse association with cancer risk. Analyses stratified by tumor stage and grade gave hint to inverse associations for localized and low-grade cancers. This study shows an inverse association between dietary intake of GLS and the risk of prostate cancer. Because this is the first prospective study using individual GLS intake data, confirmation in other studies is warranted.
Article
Epidemiological studies have shown that a diet rich in fruits and cruciferous vegetables is associated with a lower risk of prostate cancer. Indole-3-carbinol (I3C) and its dimeric product 3,3'-diindolylmethane (DIM) have been shown to exhibit anti-tumor activity both in vitro and in vivo. Recently, we have reported that a formulated DIM (B-DIM) induced apoptosis and inhibited growth, angiogenesis, and invasion of prostate cancer cells by regulating Akt, NF-kappaB, VEGF and the androgen receptor (AR) signaling pathway. However, the precise molecular mechanism(s) by which B-DIM inhibits prostate cancer cell growth and induces apoptosis have not been fully elucidated. Most importantly, it is not known how B-DIM affects cell cycle regulators and proteasome activity, which are critically involved in cell growth and apoptosis. In this study, we investigated the effects of B-DIM on proteasome activity and AR transactivation with respect to B-DIM-mediated cell cycle regulation and induction of apoptosis in both androgen-sensitive LNCaP and androgen-insensitive C4-2B prostate cancer cells. We believe that our results show for the first time the cell cycle-dependent effects of B-DIM on proliferation and apoptosis of synchronized prostate cancer cells progressing from G(1) to S phase. B-DIM inhibited this progression by induction of p27(Kip1) and down-regulation of AR. We also show for the first time that B-DIM inhibits proteasome activity in S phase, leading to the inactivation of NF-kappaB signaling and induction of apoptosis in LNCaP and C4-2B cells. These results suggest that B-DIM could be a potent agent for the prevention and/or treatment of both hormone sensitive as well as hormone-refractory prostate cancer.
Article
The risk for prostate cancer increases with age, with a family history of the disease and with living in a Westernized society, especially for blacks. Although there is no doubt that genetic factors are important, and might explain some of the geographical variation in rates, the differences between populations are so large that environmental factors must also be important. The evidence suggesting that dietary fat and/or meat may increase risk is quite consistent. The observed relative risks are small (about a 30% increase for high v. low consumption) but may have been underestimated because of inaccurate measurement of diet and further study of this topic is needed. The evidence does not support the hypothesis that carotene intake is associated with risk. There is reasonably consistent evidence suggesting that an increased risk for prostate cancer is associated with a high level of sexual activity and/or a history of sexually transmitted disease, and with vasectomy. These observations need further investigation to eliminate the possibility that they are due to biases. Much more information is needed. Prospective studies, with dietary and lifestyle questionnaires and stored blood samples, are needed to answer the outstanding questions.
Article
An adjusted rank correlation test is proposed as a technique for identifying publication bias in a meta-analysis, and its operating characteristics are evaluated via simulations. The test statistic is a direct statistical analogue of the popular "funnel-graph." The number of component studies in the meta-analysis, the nature of the selection mechanism, the range of variances of the effect size estimates, and the true underlying effect size are all observed to be influential in determining the power of the test. The test is fairly powerful for large meta-analyses with 75 component studies, but has only moderate power for meta-analyses with 25 component studies. However, in many of the configurations in which there is low power, there is also relatively little bias in the summary effect size estimate. Nonetheless, the test must be interpreted with caution in small meta-analyses. In particular, bias cannot be ruled out if the test is not significant. The proposed technique has potential utility as an exploratory tool for meta-analysts, as a formal procedure to complement the funnel-graph.
Article
Malignant transformation of the prostate and progression of carcinoma appear to be the consequence of a complex series of initiation and promotional events under genetic and environmental influences. Increased incidence of the condition may be the result of improved detection, greater awareness of the condition, and possibly an increased life expectancy accompanied by a decrease in competing causes of death rather than a true increase in the prevalence of the disease. The marked racial and geographic differences are probably multifactorial, with genetic, environmental, and possibly social influences affecting progression of the disease. Among several risk factors, evidence for the familial inheritance of some prostate cancers is compelling. Dietary influences, hormonal milieu, and the role of environmental carcinogens are currently under intense investigation. As further risk factors are identified, it will become increasingly important to identify individuals at increased risk for the disease. These men should undergo regular evaluation with state-of-the-art methods.
Article
The association between 21 vegetables and eight fruits and prostate cancer risk was assessed in the Netherlands Cohort Study among 58,279 men of ages 55-69 years at baseline in 1986. After 6.3 years of follow-up, 610 cases with complete vegetable data and 642 cases with complete fruit data were available for analysis. In multivariate case-cohort analyses, the following rate ratios (RRs) and 95% confidence intervals (CIs) for vegetable consumption were found (comparing highest versus lowest quintile): total vegetables (RR, 0.80; CI, 0.57-1.12); prepared vegetables (RR, 0.85; CI, 0.61-1.19); and raw vegetables (RR, 0.96; CI, 0.69-1.34). For vegetables categorized in botanical groups, no associations were found except for consumption of pulses (RR, 0.71; CI, 0.51-0.98; P for trend, 0.01). The RRs for total fruit and citrus fruit were 1.31 (CI, 0.96-1.79) and 1.27 (CI, 0.93-1.73), respectively; the corresponding Ps for trend were 0.02 and 0.01, respectively. In a continuous model, no association for total fruit was observed. Individual vegetables and fruits were evaluated as continuous variables (g/day). Nonsignificant inverse associations (RRs per increment of 25 g/day) were found for consumption of kale (RR, 0.74), raw endive (RR, 0.72), mandarins (RR, 0.75), and raisins or other dried fruit (RR, 0.49). Observed positive associations were significant for consumption of leek (RR, 1.38) and oranges (RR, 1.07) and nonsignificant for sweet peppers (RR, 1.60) and mushrooms (RR, 1.49). Results in subgroups of cases were more or less consistent with the overall results. From our study, we cannot conclude that vegetable consumption is important in prostate cancer etiology, but for certain vegetables or fruits, an association cannot be excluded.
Article
To evaluate the relationship between prostate cancer and several potential lifestyle risk factors. We analyzed data obtained from a population-based case-control study conducted in eight Canadian provinces. Risk estimates were generated by applying multivariate logistic regression methods to 1623 histologically confirmed prostate cancer cases and 1623 male controls aged 50-74. Cases were more likely to have a first-degree relative with a history of cancer, particularly prostate cancer (OR = 3.1, 95% CI = 1.8-5.4). Reduced risks of prostate cancer were observed among those of Indian descent (OR = 0.2, 95% CI = 0.1-0.5) or any Asian descent (OR = 0.3, 95% CI = 0.2-0.6) relative to those of western European descent. Total fat consumption, tomato and energy intake, were not associated with prostate cancer. The risk of prostate cancer was inversely related to the number of cigarettes smoked daily (p = 0.06) and cigarette pack-years (p < 0.01), while no association was observed between the total number of smoking years or the number of years since smoking cessation. Anthropometric measures and moderate and strenuous levels of leisure time physical activity were not strongly related to prostate cancer. In contrast, strenuous occupational activities at younger ages appeared protective. Our analyses are limited by the absence of data related to tumor severity and screening history. Further studies are needed to investigate the relationship between behavioral risk factors and prostate cancer screening practices.
Article
Epidemiological data on most cancer sites suggest that consumption of plant foods, which contain high levels of antioxidants, might slow or prevent the appearance of cancer. We used data from three case-control studies to test this hypothesis. The total study population consisted of 617 incident cases of prostate cancer and 636 population controls from Ontario, Quebec, and British Columbia. Dietary information was collected by an in-person interview with a detailed quantitative dietary history. Unconditional logistic regression analyses were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). A decreasing, statistically significant association was found with increasing intakes of green vegetables (OR = 0.54, 95% CI = 0.40-0.71 for 4th quartile), tomatoes (OR = 0.64, 95% CI = 0.45-0.91), beans/lentils/nuts (OR = 0.69, 95% CI = 0.53-0.91), and cruciferous vegetables (OR = 0.69, 95% CI = 0.52-0.91 for 3rd quartile). Higher intakes of fruit were associated with higher ORs (OR = 1.51, 95% CI = 1.14-2.01 for 4th quartile), an effect that was seen for total fruit and citrus fruit, as well as for all other noncitrus fruits. Among the grains, refined-grain bread intake was associated with a decrease in risk (OR = 0.65 for 4th quartile), whereas whole-grain breakfast cereals were associated with a higher risk for prostate cancer. Of all the antioxidant nutrients studied, the ORs were higher with higher intakes of cryptoxanthin (OR = 1.44, 95% CI = 1.09-1.89 for 4th quartile). Exposure to certain dietary components of plant origin, which are potentially modifiable, indicates the theoretical scope for reducing the risk from prostate cancer. Future experimental studies or trials are warranted for further understanding.
Article
There is extensive and consistent evidence that high fruit and vegetable intakes are associated with decreased risks of many cancers, but results for prostate cancer risk have been inconsistent. We studied the associations of fruit and vegetable intakes with prostate cancer risk in a population-based, case-control study of men under 65 years of age. Case participants were 628 men from King County (Seattle area), WA, who were newly diagnosed with prostate cancer. Control participants were 602 men recruited from the same underlying population and frequency matched to case participants by age. Self-administered food-frequency questionnaires were used to assess diet over the 3- to 5-year period before diagnosis or recruitment. Daily nutrient intakes were calculated by use of a nutrient database with recently updated analytic values for carotenoids. Odds ratios for prostate cancer risk associated with foods and nutrients were calculated by use of unconditional logistic regression. No associations were found between fruit intake and prostate cancer risk. The adjusted odds ratio (ORs) for the comparison of 28 or more servings of vegetables per week with fewer than 14 servings per week was 0.65 (95% confidence interval [CI] = 0.45-0.94), with a two-sided P for trend =.01. For cruciferous vegetable consumption, adjusted for covariates and total vegetable intake, the OR for comparison of three or more servings per week with less than one serving per week was 0.59 (95% CI = 0.39-0.90), with a two-sided P for trend =.02. The OR for daily intake of 2000 microg or more lutein plus zeaxanthin compared with an intake of less than 800 microg was 0.68 (95% CI = 0.45-1.00). These results suggest that high consumption of vegetables, particularly cruciferous vegetables, is associated with a reduced risk of prostate cancer.
Article
The evidence for a protective effect of vegetables, fruits, and legumes against prostate cancer is weak and inconsistent. We examined the relationship of these food groups and their constituent foods to prostate cancer risk in a multicenter case-control study of African-American, white, Japanese, and Chinese men. Cases (n = 1619) with histologically confirmed prostate cancer were identified through the population-based tumor registries of Hawaii, San Francisco, and Los Angeles in the United States and British Columbia and Ontario in Canada. Controls (n = 1618) were frequency-matched to cases on ethnicity, age, and region of residence of the case, in a ratio of approximately 1:1. Dietary and other information was collected by in-person home interview; a blood sample was obtained from control subjects for prostate-specific antigen determination. Odds ratios (OR) were estimated using logistic regression, adjusting for age, geographic location, education, calories, and when indicated, ethnicity. Intake of legumes (whether total legumes, soyfoods specifically, or other legumes) was inversely related to prostate cancer (OR for highest relative to lowest quintile for total legumes = 0.62; P for trend = 0.0002); results were similar when restricted to prostate-specific antigen-normal controls or to advanced cases. Intakes of yellow-orange and cruciferous vegetables were also inversely related to prostate cancer, especially for advanced cases, among whom the highest quintile OR for yellow-orange vegetables = 0.67 (P for trend = 0.01) and the highest quintile OR for cruciferous vegetables = 0.61 (P for trend = 0.006). Intake of tomatoes and of fruits was not related to risk. Findings were generally consistent across ethnic groups. These results suggest that legumes (not limited to soy products) and certain categories of vegetables may protect against prostate cancer.
Article
Epidemiological studies have yielded conflicting results on the associations of diet with prostate cancer. We review evidence that Brassica vegetables are associated with reduced prostate cancer risk. Brassica vegetables, which include broccoli, cabbage, mustard and collard greens, and bok choy, contain glucosinolates, the metabolic breakdown products of which are potent modulators of xenobiotic-metabolizing enzymes that protect DNA from damage. Twelve published studies give some information about Brassica vegetables and prostate cancer risk; six of these studies can be clearly interpreted. Of these, three reported statistically significant reduced risks (P < 0.05) and one reported a borderline significant reduced risk (P = 0.06) with high Brassica vegetable consumption. The epidemiological literature provides modest support for the hypothesis that high intakes of Brassica vegetables reduce prostate cancer risk.