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ABSTRACT: Epidemiologic studies that examine whether isoflavone consumption protects against breast cancer have yielded inconsistent results. The controversy focuses on the effects of the menopausal status and exposure dose of isoflavone. We aim to conduct a meta-analysis on the association between isoflavone intake and breast cancer risk by comprehensively assessing isoflavone exposure in the targeted populations. We searched PUBMED and EMBASE databases for case-control and cohort studies that assess the association between isoflavone intake and breast cancer risk. We extracted relative risks (RR) and odds ratios (OR) of different reported categories of isoflavone intake from each study. Fixed- or random-effects models were used to summarize dose-response data. Twenty-two studies were selected for the meta-analysis. Overall, the results showed that isoflavone reduced the breast cancer risk (a combined RR/OR of 0.68, 95% CI: 0.52-0.89) in Asian populations rather than Western populations (a combined RR/OR of 0.98, 95% CI: 0.87, 1.11) for the high-dose category. Further analysis showed that the intake of isoflavone in postmenopausal Asian women 0.46 (95% CI: 0.28-0.78) was better than premenopausal 0.63 (95% CI: 0.50-0.80) but similar in postmenopausal Western women 1.00 (95% CI: 0.98-1.02) and premenopausal 0.99 (95% CI: 0.87-1.12). Exposure to high isoflavone may be associated with a reduced breast cancer risk in Asian populations, especially in postmenopausal women. However, no significant difference in the studies of Western populations may be due to the low intake of isoflavone levels.
Asia Pacific Journal of Clinical Nutrition 01/2013; 22(1):118-27. · 1.13 Impact Factor
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ABSTRACT: Increased intracellular reactive oxygen species (ROS) is crucial for vascular endothelial dysfunction, a key step in the initiating of atherosclerosis (AS). The antioxidant activity of flavonoids has been suggested to contribute to AS prevention. However, The association of the structure characteristics to antioxidant capacities in relation to the inhibitory effects on endothelial dysfunction has not been well established. In this study, four subclasses of flavonoids with similar structures, including two anthocyanins (delphinidin and cyanidin), two flavonols (myricetin and quercetin), two flavones (luteolin and apigenin) and two isoflavones (genistein and daidzein) were examined for their inhibitory effects on intracellular ROS-mediated signaling pathway in the human umbilical vein endothelial cell EA.hy926. Cells were pretreated with different flavonoids for 2 h and then exposed to oxLDL of 100 μg/ml for another 24 h. It was found that treatment with different flavonoids alone had no notable effects on cell viability. However, the oxLDL-induced decrease of cell viability, generation of O(2)(·-) and ROS, p38MAPK activation, NF-κB nuclear translocation, NF-κB-modulated transcriptional activity as well as the mRNA expression of genes including ICAM-1, VCAM-1, E-selectin, MMP-1, MMP-2 and MMP-9 were notably inhibited by the pretreatment of different flavonoids through blunting ROS-triggered signaling pathway, in spite of apparent differences. And the number of hydroxyl groups in total, 3',4'-ortho-dihydroxyl in B-ring and 3-hydroxyl group in C-ring of flavonoids were important structure characteristics for the inhibitory effects. Thus, anthocyanins and flavonols such as delphinidin and myricetin exert higher ROS scavenging activities and more significant endothelium-protective effects compared to the other compounds. Our results provide evidence for AS prevention and a basis for designing the potent anti-atherosclerotic agents.
Biochimie 06/2012; 94(9):2035-44. · 3.02 Impact Factor
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ABSTRACT: We investigate the cytoprotective effects and the molecular mechanism of genistein in oxidative stress-induced injury using an endothelial cell line (EA.hy926). An oxidative stress model was established by incubating endothelial cells with H2O2. According to the present results, genistein pretreatment protected endothelial cells against H2O2-induced decreases in cell viability and increases in apoptosis. Genistein also prevented the inhibition of B-cell lymphoma 2 and the activation of caspase-3 induced by H2O2. Genistein increased superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels and attenuated the decrease in these antioxidants during oxidative stress. We also found that genistein induced the promoter activity of both nuclear factor erythroid 2-related factor 2 (Nrf2) and PPARγ. Additionally, genistein induced the nuclear translocation of Nrf2 and PPARγ. While genistein caused the up-regulation of both Nrf2 and PPARγ, it also activated and up-regulated the protein expression and transcription of a downstream protein, haem oxygenase-1 (HO-1). Moreover, the use of Nrf2 small interfering RNA transfection and HO-1- or PPARγ-specific antagonists (Znpp and GW9662, respectively) blocked the protective effects of genistein on endothelial cell viability during oxidative stress. Therefore, we conclude that oxidative stress-induced endothelial cell injury can be attenuated by treatment with genistein, which functions via the regulation of the Nrf2 and PPARγ signalling pathway. Additionally, the endogenous antioxidants SOD, CAT and GSH appear to play a role in the antioxidant activity of genistein. The present findings suggest that the beneficial effects of genistein involving the activation of cytoprotective antioxidant genes may represent a novel strategy in the prevention and treatment of cardiovascular endothelial damage.
The British journal of nutrition 05/2012; · 3.45 Impact Factor
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ABSTRACT: Objectiveour previous studies have demonstrated that HER-2/neu gene expression in human breast cancer MCF-7 cells promotes angiogenesis
in MCF-7 cells xenograft tumors, and genistein inhibits angiogenesis in MCF-7 cells with HER-2/neu expression xenograft tumors.
Here, the effects of genistein on the expression of vascular endothelial growth factor (VEGF) in MCR-7 cells with HER-2/neu
expression were further studied for exploring the molecular mechanism of anti-angiogenesis in HER-2/neu-overexpressing breast
cancer by genistein.
MethodsHER-2/neu-overexpressing MCF-7 cells (MCF-7/HER-2) were established by transfecting HER-2/neu gene into HER-2/neu negative
expression breast cancer MCF-7 cells. Immunocytochemical staining, western blot and reverse transcription-polymerase chain
reaction (RT-PCR) were adopted to measure the expression of VEGF in MCF-7/HER-2 cells treated by genistein for 24, 48 and
72h.
ResultsHER-2/neu expression up-regulated VEGF mRNA and protein in MCF-7 cells, genistein decreased VEGF mRNA and protein level in
MCF-7/HER-2 cells in a time-dependent manner.
ConclusionThese results suggest that VEGF plays an important role in HER-2/neu gene expression promoted antiogenesis in breast cancer
and genistein induced down-regulation of the expression of VEGF may be one of the molecular mechanisms of its anti-angiogenesis
in HER-2/neu-overexpressing breast cancer.
Chinese Journal of Cancer Research 04/2012; 18(2):83-87. · 0.18 Impact Factor
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ABSTRACT: Monocyte adhesion to the vascular endothelium and their subsequent trans-endothelial migration are pivotal early events in atherogenesis. In this study, the effect of delphinidin, belonging to the group of anthocyanin, on adhesion of monocytes to endothelial cells induced by ox-LDL was investigated. The results showed that the pre-treatment with delphinidin (50, 100, or 200 μM) dose-dependently decreased the ox-LDL-induced up-regulation of the expression of ICAM-1 and P-selectin, and the enhanced adhesion and transmigration of monocytes. To determine the role of ROS/p38MAPK/NF-κB pathway, intracellular ROS level, p38MAPK protein expression, NF-κB transcription activity and protein expression, IκB-α degradation, NADPH oxidase subunit (Nox2 and p22phox) protein, and mRNA expression were measured. The results showed that delphinidin attenuated ox-LDL-induced generation of ROS, p38MAPK protein expression, NF-κB transcription activity and protein expression, IκB-α degradation, NADPH oxidase subunit (Nox2 and p22phox) protein and mRNA expression in endothelial cells in a dose-dependent manner. These results suggest that delphinidin attenuates ox-LDL induced expression of adhesion molecules (P-selectin and ICAM-1) and the adhesion of monocytes to endothelial cells by inhibiting ROS/p38MAPK/NF-κB pathway. These findings provide a basis for the design of potent antiatherosclerotic agents that will have therapeutic potential in the prevention of AS.
Cell biochemistry and biophysics 06/2011; 61(2):337-48. · 3.34 Impact Factor
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ABSTRACT: Vascular endothelial dysfunction induced by oxidative stress has been demonstrated to be the initiation step of atherosclerosis (AS), and flavonoids may play an important role in AS prevention and therapy. Twenty-three flavonoids categorized into flavones, flavonols, isoflavones, and flavanones, all with 4-oxo-pyronenucleus, were examined for what structural characteristics are required for the inhibitory effects on endothelial dysfunction induced by oxidized low-density lipoprotein (oxLDL). Human vascular endothelial cells EA.hy926 were pretreated with different 4-oxo-flavonoids for 2 hs, and then exposed to oxLDL for another 24 hs. Cell viability and the level of malondialdehyde (MDA), nitric oxide (NO) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured, respectively. Then, correlation analysis and paired comparison were used to analyze the structure-activity relationships. Significant correlations were observed between the number of -OH moieties in total or in B-ring and the inhibitory effectson endothelial dysfunction. Furthermore, 3',4'-ortho-dihydroxyl on B-ring, 3-hydroxyl on C-ring and 2,3-double bondwere correlated closely to the inhibitory effects of flavonolson cell viability decrease and lipid peroxidation. 5,7-meta-dihydroxyl group on A-ring was crucial for the anti-inflammatory effects of flavones and isoflavones in endothelial cells. Moreover, the substituted position of B-ring on C3 rather than C2 was important for NO release. Additionally, hydroxylation at C6 position significantly attenuated the inhibitory effects of 4-oxo-flavonoids on endothelial dysfunction. Our findings indicated that the effective agents in inhibiting endothelial dysfunction include myricetin, quercetin, luteolin, apigenin, genistein and daidzein. Our work might provide some evidence for AS prevention and a strategy for the design of novel AS preventive agents.
International Journal of Molecular Sciences 01/2011; 12(9):5471-5489. · 2.60 Impact Factor
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ABSTRACT: Breast cancer is the most common malignancy in women worldwide and pharmaceutical agents have therapeutic and preventive effects in breast cancer. The human epidermal growth factor receptor 2/neu is one of the most important oncogenes in human breast cancer. Prepubertal exposure to endogenous estradiol and a phytoestrogen, genistein (Gen), has been shown to reduce future breast cancer risk. Gen downregulates tyrosine kinase regulated protein expression and reduces prostate cancer. In this study, the effects of prepubertal exposure to Gen on rat mammary carcinogenesis and the erbB2/Akt signal pathway were investigated. Prepubertal female Sprague-Dawley rats were daily exposed to Gen at 125 mg/kg (Gen-1) and 500 mg/kg (Gen-5) from postnatal days 22-28. Subsequently, the rats were given a single dose of 100 mg/kg 7.12-dimethylbenz [a] anthracene on postnatal day 42 to induce mammary tumor. The mRNA expression of erbB2 and amplified in breast cancer 1 (AIB1) was detected by reverse transcription-polymerase chain reaction. The protein levels of proliferating cell nuclear antigen (PCNA), erbB2, phosphotyrosine protein, Akt, and p-Akt were detected by immunohistochemistry and Western blotting. The activity of protein tyrosine kinase (PTK) was detected by liquid scintillation counting. The percentage of rats with mammary tumors in breast cancer model (BCM), Gen-1, and Gen-5 was 71.43, 52.38, and 33.34%, respectively. The incidence of 7.12-dimethylbenz [a] anthracene-induced mammary tumors significantly decreased in Gen-5 compared with that in BCM. The mRNA levels of AIB1 and erbB2 and the protein levels of erbB2, p-Akt, and PCNA protein expression were downregulated for a long time in the mammary tumors in Gen-5 groups. The activity of PTK was also decreased for a long time. However, the total Akt protein expression did not change significantly among BCM, Gen-1, and Gen-5. Prepubertal exposure of Sprague-Dawley female rats to 500 mg/kg Gen can reduce later breast cancer risk and its protective effect is associated with persistent downregulation of the expression of erbB2, p-Akt, AIB1, and PCNA and with low PTK activity in the mammary tumor. Our results suggest that erbB2/Akt signaling plays a role in tumor formation and targeting erbB2/Akt signaling with prepubertal exposure to Gen may provide greater efficacy to the current therapies used to treat tumors.
European journal of cancer prevention: the official journal of the European Cancer Prevention Organisation (ECP) 03/2010; 19(2):110-9. · 2.21 Impact Factor
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ABSTRACT: Anthocyanins may play an important role in atherosclerosis prevention. However, the structure-function relationships are not well understood. The objective of this study was to compare the inhibitory effect of 21 anthocyanins against oxidized low-density lipoprotein-induced endothelial injury to understand the relationship between anthocyanin chemical structure and the endothelial protective properties, measured as cell viability, MDA production and NO release. Additionally, the intracellular anti-radical activity of the selected anthocyanins was investigated to identify the correlation with endothelial protection. Our results provide evidence that the number of -OH in total or in B-ring, 3',4'-ortho-dihydroxyl and 3-hydroxyl are the main structural requirements of anthocyanins in suppressing oxidative stress-induced endothelial injury and such inhibitory effect was significantly correlated with the intracellular radical scavenging activity.
FEBS letters 12/2009; 584(3):583-90. · 3.54 Impact Factor
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ABSTRACT: Moderate consumption of natural dietary polyphenolic compounds can reduce the risk of cardiovascular diseases. Here we investigated the protective effects of delphinidin against oxidized low-density lipoprotein (oxLDL)-induced damage in human umbilical vein endothelial cells (HUVECs). The MTT assay showed that 2h pre-incubation with delphinidin markedly restored the oxLDL-induced viability loss in HUVECs in a concentration-dependent manner. This effect was accompanied by a significant decrease in intracellular reactive oxygen species. Moreover, delphinidin imposed preventive effects on suppressing the production of lipid peroxidation, restoring the activities of endogenous antioxidants, and increasing the level of nitric oxide. Pre-incubation of delphinidin with HUVECs led to the reduction of apoptosis. Finally, delphinidin can efficiently prevent the down-regulation of Bcl-2 protein and up-regulation of Bax protein. Together, our findings suggest that delphinidin can effectively protect HUVECs against oxidative stress induced by oxLDL, which may be important for preventing both plaque development and stability in atherosclerosis.
Chemico-biological interactions 10/2009; 183(1):105-12. · 2.46 Impact Factor
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ABSTRACT: In this study, the effects of dietary fatty acids on the fatty acid compositions and lipid metabolic-related genes expression in N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinogenesis were evaluated. The 50-day-old female Sprague-Dawley rats were intervened by different dietary fats (15% wt/wt), including saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), n-6 polyunsaturated fatty acid (PUFA), n-3 PUFA, 1:1 n-6/n-3, 5:1 n-6/n-3, 10:1 n-6/n-3, and 1:2:1 S/M/P (1:1 n-6/n-3), alone or in combination with MNU. There was no mammary tumor occurrence in the control and MNU-treated n-3 PUFA groups after 18 wk. n-3 PUFA diet retarded the weight growth of rats. 1:1 n-6/n-3 diet significantly reduced the MNU-induced tumor incidence and tumor multiplicity compared with SFA, MUFA, n-6 PUFA, 5:1 n-6/n-3, 10:1 n-6/n-3 and 1:2:1 S/M/P diets (42.86% vs. 83.33%-92.31%, 0.79 vs. 2.62-2.85, P < 0.01). Additionally, 1:1 n-6/n-3 diet substantially increased cis-5,8,11,14,17-eicosapentaenoic acid and cis-4,7,10,13,16,19-docosahexaenoic acid levels, whereas it decreased C20:4 level and the mRNA expressions of fatty acid synthase, Cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) in mammary tissues (P < 0.05). These results suggest that 1:1 n-6/n-3 in the diet is effective in the prevention of mammary tumor development by increasing the n-3 PUFA content and reducing the expression of lipid metabolic-related genes.
Nutrition and Cancer 02/2008; 60(6):810-25. · 2.78 Impact Factor
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ABSTRACT: Recently, researches refer to the influence of polyunsaturated fatty acid (PUFA) on cancer initiation and progression had been highly concerned. This study was to investigate the effects of 2 kinds of omega-3 PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the metastatic ability of human prostate cancer cell line PC-3, and explore the role of Rho GTPase in inhibiting cancer metastasis by omega-3 PUFA.
MTT assay was used to determine the effects of omega-3 PUFA on the proliferation of PC-3 cells. Adhesion assay, invasion assay, and migration assay were used to observe the effects of omega-3 PUFA on the metastatic ability of PC-3 cells. Western blot was used to observe the effects of omega-3 PUFA on the expression of RhoA, Rac1, Rac2, and Cdc42 proteins in PC-3 cells. Laser confocal microscopy was used to investigate the effect of omega-3 PUFA on the reorganization of the microfilaments and microtubules marked by immunofluorescent cytochemistry technology.
Both EPA and DHA inhibited the proliferation of PC-3 cells, and the proliferation inhibition rate increased along with the increase of the concentration and treatment time. When treated with 60 mumol/L EPA or DHA for 48 h, the abilities of adhesion, invasion and migration of PC-3 cells were inhibited (P<0.05). omega-3 PUFA significantly suppressed the expression of Rac1, Rac2 and Cdc42 proteins (P<0.05), influenced the distribution and structure of sytoskeletons.
omega-3 PUFA could inhibit the metastatic ability of PC-3 cells through down-regulating the expression of Rho GTPase and inhibiting the cytoskeleton reorganization.
Ai zheng = Aizheng = Chinese journal of cancer 01/2008; 26(12):1281-6.
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ABSTRACT: Flavonoids, with some beneficial biological activities, exist extensively in foods and herbal products. This study was to evaluate the effects of 23 flavonoids on the proliferation of leukemia cell line HL-60, and elucidate the structure-activity relationship (SAR).
HL-60 cells were treated with 23 flavonoids with high purity and definite structure. Cell proliferation was detected by MTT assay. The 50% inhibition concentrations (IC50) of the 23 flavonoids were calculated. The effects of particular structures on IC50 were evaluated.
Most of the 23 flavonoids inhibited the proliferation of HL-60 cells distinctly, and the effects were enhanced along with increasing concentrations. However, the intensity of their effects were different, which were arranged from strong to weak as follows:3,6-dihydroxyflavone > luteolin > geraldol > 2'-hydroxyflavanone > apigenin > 3,7-dihydroxyflavone > myricetin > fisetin > baicalein > quercetin > flavanone > chrysin > galangin > 4'-hydroxyflavanone > 6-hydroxyflavone > genistein > flavone >7-hydroxyflavone > daidzein > hesperetin > naringenin. The 2,3-double bond in ring C, appropriate hydroxyls, ring B attached at position 2, hydroxyls in position 3, ortho-substituting hydroxyls in ring B were related to enhanced inhibitory effects of flavonoids on the proliferation of HL-60 cells, while the lack of 2,3-double bond, deficiency or redundancy of hydroxyl groups, hydroxyl group in position 5, 7 or meta-substituting hydroxyls in ring B, isoflavone structure were related to reduced inhibitory effects of flavonoids.
The 2,3-double bond in ring C, appropriate hydroxyls, ring B attached at position 2, hydroxyls in position 3, ortho-substituting hydroxyls in ring B may be key structural requirements of flavonoids for potent cytotoxicity to HL-60 cells.
Ai zheng = Aizheng = Chinese journal of cancer 01/2008; 26(12):1309-14.
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ABSTRACT: To study the effects of different dietary fatty acid on the expression of nuclear receptor genes in the breast cancer of rats.
Fifty-day-old female Sprague-Dawley rats were fed on eight different diets containing following fatty acids: saturated fatty acid (SFA); monounsaturated fatty acid (MUFA); n-6 polyunsaturated fatty acid (PUFA); n-3 PUFA; 1:1 n-6/n-3; 5:1 n-6/n-3; 10:1 n-6/n-3; 1:2:1 S/M/P (n-6/n-3 at 1:1). The rats were given a single intraperitoneal injection of methyl-nitrosourea (MNU) at 50 mg/kg body weight to establish the rat model of mammary carcinogenesis, the ultrastructure changes of mammary gland cells in rats were observed by transmission electron microscope, the cell proliferation activity was detected by BrdU-labeled immunocytochemistry, and the expression of PPARbeta and PPARgamma mRNA were assayed by RT-PCR.
There was no breast cancer occurring in control groups and the MNU-treated n-3 PUFA group, and the ultrastructure and proliferation activity of mammary gland cells in these groups were normal. In contrast, there appeared obvious marker of adenocarcinomas in mammary gland cells of MNU-induced breast cancer, and a high cell proliferation activity was found in tumor growth-enhancing groups (SFA, MUFA, n-6 PUFA, 5:1 n-6/n-3, 10:1 n-6/n-3 and S/M/P, 21% - 22% of BrdU-labeled cells), while a low cell proliferation activity was detected in rats fed with 1:1 n-6/n-3 diet (13% of BrdU-labeled cells, P < 0.05). Moreover, peroxisome proliferator-activated receptors (PPARs), as important nuclear receptor genes of relating lipid metabolism, the expressions of PPARbeta and PPARgamma mRNA were significantly up-regulated in mammary adipose tissues of MNU-induced breast cancer as compared with the control groups, but the expression levels of peroxisome proliferator-activated receptors (PPARs) in rats fed with 1:1 n-6/n-3 group were lowest (P < 0.05).
The different dietary fatty acid compositions should diversely adjust the expression of PPARs gene in rats, which maybe have an important role in affecting incidence of breast cancer.
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 07/2007; 41(4):271-6.
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ABSTRACT: Lovastatin, an inhibitor of cellular cholesterol synthesis, has an apparent anti-cancer property, but the detailed mechanisms of its anti-cancer effects remain poorly understood. We investigated the molecular mechanism of Lovastatin anti-tumor function through the study of its effect on membrane ion flow, gap junctional intercellular communication (GJIC), and the pathways of related signals in MCF-7 mammary cancer cells. After treatment for 24-72 h with 4, 8 or 16 micromol/L Lovastatin, cellular proliferation was examined via the MTT assay, and changes in membrane potential and cellular [Ca(2+)](i) were monitored using confocal laser microscopy. In addition, the expression of plasma membrane calcium ATPase isoform 1 (PMCA1) mRNA was analyzed via RT-PCR, the GJIC function was examined using the scrape-loading dye transfer (SLDT) technique, and MAPK phosphorylation levels were tested with the kinase activity assay. The results showed that Lovastatin treatment significantly inhibited the growth of MCF-7 breast cancer cells. It also increased the negative value of the membrane potential, leading to the hyperpolarization of cells. Moreover, Lovastatin treatment continuously enhanced [Ca(2+)](i), although the levels of PMCA1 mRNA were unchanged. GJIC was also upregulated in MCF-7 cells, with transfer of LY Fluorescence reaching 4 to 5 rows of cells from the scraped line after treatment with 16 micromol/L Lovastatin for 72 h. Finally, downregulation of ERK1 and p38(MAPK) phosphorylation were found in Lovastatin-treated MCF-7 cells. It could be deduced that Lovastatin can induce changes in cellular hyperpolarization and intracellular Ca(2+) distributions, and increase GJIC function. These effects may result in changes in the downstream signal cascade, inhibiting the growth of MCF-7 cells.
Cellular & Molecular Biology Letters 02/2007; 12(1):1-15. · 1.50 Impact Factor
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ABSTRACT: Radiation protection from death and stimulating hematopoietic recovery by oral administrations of genistein, 160 mg/kg b.w., once daily for seven consecutive days before whole-body gamma-rays irradiation, were confirmed by tests with adult male BALB/c mice. Moreover, the protective action of genistein was compared to that of diethylstilbestrol (DES). Based on the studies of survival, behavior of hematograms, endogenous hematopoietic spleen colony formation (endoCFUs), and numbers of nucleated cell, granulocyte-macrophage colony forming units (CFU-GM) in bone marrow following irradiation, it was demonstrated that genistein was an effective radioprotector. The survival of irradiated mice protected by genistein was significantly increased and statistically higher than that of mice pre-treated with DES. Stimulated recovery of leukocytes, erythrocytes, lymphocytes and thrombocytes were observed in mice pre-treated with genistein or DES, however, the effects of genistein on promoting recovery of bone marrow nucleated cells, leukocytes and lymphocytes were significantly higher than those of DES. Enhanced endoCFUs, numbers of bone marrow nucleated cells and CFU-GM were also found in mice pre-treated with genistein as well as DES. Meanwhile, endoCFU numbers in mice pre-treated with genistein was 3.47-fold higher than that in the irradiated control group, although no significant difference was found between genistein administration and DES administration. It could be deduced that the radioprotective action against death is induced by a possible process of enhanced regeneration of the hematopoietic stem cells due to not only strengthened radioresistance and increased numbers of remained hematopoietic cells, but also enhanced post-irradiation repair or promoted proliferation of the hematopoietic stem cells. These effects of genistein may have some therapeutic implications for radiation-induced injuries.
Journal of Radiation Research 01/2006; 46(4):425-33. · 1.68 Impact Factor
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ABSTRACT: The breast and ovarian cancer susceptibility gene BRCA1 acts as a tumor suppressor gene, its product expresses in a cell cycle-dependent manner. Inheritance of a mutant allele of BRCA1 leads to increased risk of developing breast,and ovarian cancers. Lovastatin, as a potent inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase),is the main rate-limiting enzyme of endogenous cholesterol biosynthesis pathway. This study was to evaluate the effect and mechanism of combined application of BRCA1 and lovastatin on cell cycle distribution of MCF-7 cells.
MCF-7 cells were transfected with expression vector pcDNA3-beta-HA-hsBRCA1 containing full-length BRCA1, and named MCF-7BRCA1 cells. The expression of BRCA1 gene was examined with reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. After cultured with 8 micromol/L lovastatin, growth curve and MTT assay were used to determine cell proliferation capacity; the cell cycle distribution was measured with flow cytometry (FCM). Meanwhile,the protein expression of Cyclin D1 and retinoblastoma (Rb) were analyzed by Western blot analysis.
The pcDNA3-beta-HA-hsBRCA1 plasmids were successfully transfected into MCF-7 cells and expressed stably. The growth curve and MTT assay results showed that cell proliferation capacity decreased in the cells cultured with lovastatin for 4 days. FCM showed that S phase, and G2/M phase of BRCA1-infected cells decreased,while G0/G1 phase increased after cultured with lovastatin, the cells were blocked in G0/G1 phase at 72 h post-treatment by lovastatin. Ectopic expression of BRCA1 leads to decrease of the Rb protein and Cyclin D1 protein. Overall data showed that the effects of Lovastatin were more obviously in MCF-7BRCA1 cells than MCF-7 cells.
Overexpression of BRCA1 protein may amplify sensibility of breast cancer to lovastatin,and enhance the anti-tumor effect of lovastatin.
Ai zheng = Aizheng = Chinese journal of cancer 08/2004; 23(8):924-8.
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ABSTRACT: To study the molecular mechanism of inhibition of angiogenesis in HER-2/neu-overexpressing breast cancer by genistein, HER-2/neu negative expression breast cancer MCF-7 cells were transfected with HER-2/neu to establish HER-2/neu-overexpressing MCF-7 cells (named MCF-7/HER-2). Expression of vascular endothelial growth factor (VEGF), urokinase-type plasminogen activator (uPA), matrix metalloproteinase-2,9 (MMP-2,9) in MCF-7, MCF-7/HER-2 as well as genistein-treated MCF-7/HER-2 were measured by immunocytochemistry and Western blot. We found that the expression of VEGF, MMP-2,9 and uPA in MCF-7/HER-2 cells were highter than that in MCF-7 cells, those angiogenesis related factors expression in MCF-7/HER-2 cells significantly decreased after treatment with genistein. Genistein could inhibit expression of angiogenesis-related factors VEGF, MMP-2,9 and uPA in HER-2/neu-overexpressing breast cancer cells, and this may be part of molecular mechanism of its anti-angiogenesis in HER-2/neu-overexpressing breast cancer.
Shi yan sheng wu xue bao 07/2004; 37(3):251-3.
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ABSTRACT: To study the effect of lovastatin on the expression of IkappaBalpha and cell-cycle regulating proteins in MCF-7 cells.
MCF-7 cells were treated with 4, 8 and 16 micro mol/L lovastatin for 48 - 72 h. The distribution of cell cycles was assayed by flow cytometry (FCM). The protein expression of IkappaBalpha, CDK4, p16, pRb in cytoplasm and IkappaBalpha in the nucleus were detected by Western blot.
Lovastatin could arrest cellcycle in the G(0)/G(1) phase in a dose- and time-dependent manner, obviously lowering the expression of IkappaBalpha, CDK4 and pRb protein level in the cytoplasm and increasing IkappaBalpha in the nucleus, but not on p16 protein level.
Lovastatin can induce the arrest of cell cycle in G(0)/G(1) phase by affecting the expression of IkappaBalpha and cell-cycle regulating protein in MCF-7 cells.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 08/2003; 25(4):332-4.
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ABSTRACT: Lovastatin,an inhibitor of endogenous cholesterol biosynthesis,has been widely used in the clinical treatment of hypercholesterolemia.Recently,lovastatin has been paid more attention for its wide-range effects on human cancer cells; however,the detail mechanisms of its anti-cancer effects are not yet understood. This study was designed to investigate the effects of lovastatin on proliferation and gap junctional intercellular communication (GJIC) of MCF-7 human breast cancer cells.
After treated with lovastatin at dosages of 4,8,16 micromol/L for 1-3 days,the cell differentiation was examined with nitroblue tetrazolium (NBT) reduction test;the proliferation and distribution of cell cycles were examined with flow cytometry (FCM). Meanwhile,GJIC of MCF-7 cells was observed using the scrape-loading and dye transfer(SLDT) technique.
Lovastatin could inhibit the proliferation of MCF-7 cells significantly and 75.80 percent of cells were inhibited after treated with 16 micromol/L lovastatin for 72 hours (P< 0.05). Meanwhile, lovastatin could arrest MCF-7 cells in the G(0)/G(1) phase of cell cycle and 80 percent of cells were arrested in G(0)/G(1) phase after treated with lovastatin for 72 hours. Furthermore, lovastatin could induce the differentiation of MCF-7 cells (P< 0.01) and up-regulate GJIC in MCF-7 cells. After treated with 16 micromol/L lovastatin for 72 hours, transfer of LY fluorescence could reach 4-5 rows of cells from the scraped line. However, apoptosis in MCF-7 cells was not obvious. All these effects of lovastatin were in a dose-and time-dependent manner.
It suggests that lovastatin has the capabilities of inhibiting proliferation, arresting MCF-7 cells at G(0)/G(1) phase of cell cycle and inducing differentiation. These effects of lovastatin maybe correlate with lovastatin promoting GJIC function in MCF-7 cells.
Ai zheng = Aizheng = Chinese journal of cancer 03/2003; 22(3):257-61.
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ABSTRACT: ObjectiveTo detect the expression of glial fibrillary acid protein (GFAP) and taurine transporter (TauT) in the retinal Müller cells in high glucose culture with taurine and to explore the influence of glucose on the taurine transporting, and the possible protective effects of taurine on Müller cells in early diabetic retinopathy.MethodsThe Müller cells from the rat retina were cultured in high glucose, and GFAP and TauT expressions were detected in the cells treated with different doses of taurine by immuocy-tochemical fluorescein staining and Western blotting.ResultsHigh glucose enhanced the expression of GFAP and decreased the expression of TauT in Müller cells. Taurine decreased the up-regulation of GFAP in the cells which was induced by high glucose; 0. 1–10 mmol/L taurine increased the expression of TauT in Müller cells.ConclusionTaurine can inhibit the changes in Muller cell resulted from high glucose.
Journal of Medical Colleges of PLA.
