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Could we use antioxidants during cancer chemotherapy or not?
Abstract
Drug resistance in cancer chemotherapy and the side effects represent a major obstacle to successful treatment of cancer (1). Chemotherapeutics through different mechanisms kill cancers; however they induce oxidative stress and cause side effects in normal cells(2). Some research has proved influence of antioxidants in reducing side effects, however a reduction in chemodrug efficiancy was also observed(3). ROS signaling could be different in various cancers or cellular behavior could be different against ROS and accordingly their treatment with chemotherapeutics or the antioxidant consumption would differ. This research was focused on these aspects to sort out the relationship between ROS and drug resistance in several cancer cell lines and the effect of antioxidants on drug resistance. MCF7, A549, HT29, CaCo-2, Caov-3, KB, and normal HUVECs were studied. 5-FU as anti-tumor agent and Luperox as stressor, and Crocin and vitamin C as antioxidants were used. The cell signaling of Nrf2/HO1/NQO1 and PTEN/AKT were followed. Our results showed cancer cells could be categorized into two groups regarding the oxidative stress response. The use of antioxidants during chemotherapy could increase the efficiency of the chemotherapy and reduce the side effects or result in vein.
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Reactive oxygen species are the intermediates that are formed during the normal metabolic process which are effectively neutralized by the antioxidant system of the body. Any imbalance in this neutralization process causes oxidative stress which has been implicated as one of the cause in diseases such as Alzheimer's disease, cardiovascular disorders, cancer etc. Research has enabled the use of antioxidants as therapeutic agents in the treatment of various diseases. Literature also puts forth the negative effects of using antioxidants in the treatment of diseases. This review is a compilation of both the beneficial and detrimental effects of use of antioxidants in the treatment of diseases such as cancer, cardiovascular diseases, diabetes and oral diseases.
Purpose
The aim of this study was to examine the antioxidant activity of ginger extract oral supplement in newly diagnosed cancer patients receiving adjuvant chemotherapy compared to placebo.
Patients and methods
Newly diagnosed cancer patients receiving moderate-to-high emetogenic potential adjuvant chemotherapy were randomized to receive either a ginger extract (standardized 6-gingerol 20 mg/day) or a placebo 3 days prior to chemotherapy, which they continued daily. Oxidant/antioxidant parameters, including the activities of superoxide dismutase (SOD) and catalase (CAT) and levels of glutathione peroxidase (GPx), total glutathione (GSH/GSSG), lipid peroxidation products detected as malondialdehyde (MDA) and NO2⁻/NO3⁻, were measured at baseline and at days 1, 22, 43 and 64 after undergoing chemotherapy. Two-sided statistical analysis, with P < 0.05, was used to determine statistical significance.
Results
A total of 43 patients were included in the study: 19 and 24 patients were randomly assigned to the ginger group and placebo group, respectively. Antioxidant activity parameters, including SOD, CAT, GPx and GSH/GSSG, were significantly increased at day 64 in the ginger group compared to those in the placebo group, while MDA and NO2⁻/NO3⁻ levels were significantly decreased (P < 0.0001). When compared to the baseline, the activities of SOD and CAT and the levels of GPx and GSH/GSSG were significantly higher on day 64 (P = 0.01), while the blood levels of MDA and NO2⁻/NO3⁻ were significantly decreased (P < 0.01).
Conclusion
Daily supplement of ginger extract started 3 days prior to chemotherapy has been shown to significantly elevate antioxidant activity and reduce oxidative marker levels in patients who received moderate-to-high emetogenic potential chemotherapy compared to placebo.
Dormant breast cancers (BRCA) resurge as metastatic disease after a long dormancy period in the bone marrow where cancer cells interact with mesenchymal stem cells (MSC). However, the nature of early interactions between BRCA cells and MSC in the bone marrow microenvironment that facilitate adaptation to a quiescent state remain poorly understood. Here we report that BRCA cells prime MSC to release exosomes containing distinct miRNA contents such as miR-222/223, which in turn promotes quiescence in a subset of cancer cells and confers drug resistance. Building on these results, we developed a novel, non-toxic therapeutic strategy to target dormant BRCA cells based on systemic administration of MSC loaded with antagomiR-222/223. In an immune-deficient mouse model of dormant breast cancer, this therarpy sensitized BRCA cells to carboplatin-based therapy and increased host survival. Overall, our findings illuminate the nature of the regulatory interactions between BRCA cells and MSC in the evolution of tumor dormancy and resurgence in the micrometastatic microenvironment of the bone marrow.
Background:
Pancreatic cancer is one of the leading causes of cancer mortality. Diet may be associated with pancreatic cancer, but it is unknown whether specific dietary components contribute to its risk. The potential differential role of dietary antioxidants warrants further investigation.
Methods:
We analysed data from a case-control study of 326 pancreatic cancer cases and 652 controls conducted between 1991 and 2008 in Northern Italy. Subjects' usual diet was assessed through a validated and reproducible food frequency questionnaire. Using this information and an Italian food composition database, we calculated three indices of dietary total antioxidant capacity (TAC): Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP) and ferric-reducing antioxidant power (FRAP). We estimated the odds ratios (ORs) and 95% confidence intervals (CIs) for pancreatic cancer using multiple logistic regression models conditioned on study centre, sex and age, and adjusted for major known pancreatic cancer risk factors.
Results:
Significant inverse associations were found for the highest tertile of TAC compared with the lowest tertile for both TEAC and FRAP. The ORs were 0.61 (95% CI 0.39-0.94, P-value for trend 0.03) and 0.63 (95% CI 0.41-0.99, P-value for trend 0.05), respectively. Total radical-trapping antioxidant parameter was inversely, but not significantly, associated with pancreatic cancer risk, with an OR of 0.78 (95% CI 0.49-1.24, P-value for trend 0.27).
Conclusions:
Diet high in TAC, as measured by TEAC and FRAP, is inversely associated with pancreatic cancer risk.British Journal of Cancer advance online publication 12 May 2016; doi:10.1038/bjc.2016.114 www.bjcancer.com.
Background:
Crocus sativus and its major constituent crocin are well established to have anti-cancer properties in breast cancer cells (MCF-7). However the role of C. sativus extract (CSE) and crocin on caspase signaling mediated MCF-7 cell death at molecular level is remains unclear. In this study, we tried to unravel role of CSE and crocin on caspase mediated MCF-7 cells death and their in vivo preclinical toxicity profiling and immune stimulatory effect.
Materials and methods:
CSE extract was fractionated by HPLC and crocin was isolated and characterized by NMR, IR, and MS. MCF-7 cells were treated with both CSE and crocin and expression of Bcl-2 and Bax was assessed after 24 and 36 hours. Furthermore, caspase 3, caspase 8 and caspase 9 expression was determined by Western blotting after 24 hours of treatment. DNA fragmentation analysis was performed for genotoxicity of CSE and crocin in MCF-7 cells. The in vivo toxicity profile of CSE (300 mg/kg of b.wt) was investigated in normal Swiss albino mice. In addition, peritoneal macrophages were collected from crocin (1, 1.5 and 2 mg/kg body weight) treated mice and analyzed for ex vivo yeast phagocytosis.
Results:
Immunoblot analysis revealed that there was time dependent decline in anti-apoptotic Bcl-2 with simultaneous upregulation of Bax in CSE and crocin treated MCF-7 cells. Further CSE and crocin treatment downregulated caspase 8 and 9 and cleaved the caspase 3 after 24 hours. Both CSE and crocin elicited considerable DNA damage in MCF-7 cells at each concentration tested. In vivo toxicity profile by histological studies revealed no observable histopathologic differences in the liver, kidney, spleen, lungs and heart in CSE treated and untreated groups. Crocin treatment elicited significant dose and time dependent ex vivo yeast phagocytosis by peritoneal macrophages.
Conclusions:
Our study delineated involvement of pro-apoptotic and caspase mediated MCF-7 cell death by CSE and crocin at the molecular level accompanied with extensive DNA damage. Further we found that normal swiss albino mice can tolerate the maximum dose of CSE. Crocin enhanced ex vivo macrophage yeast phagocytic ability.
Background: Approximately 30% of breast cancer patients receive chemotherapy, yet little is known about influences of current regimens on circulating lymphocyte levels and phenotypes. Similarly, clinico-pathological factors that modify these influences, and implications for future immune health remain mainly unexplored.
Methods: We used flow-cytometry to assess circulating lymphocyte levels and phenotypes in 88 primary breast cancer patients before chemotherapy and at time-points from 2 weeks to 9 months after chemotherapy completion. We examined circulating titres of antibodies against pneumococcal and tetanus antigens using ELISAs.
Results: Levels of B, T and NK cells were significantly reduced 2 weeks after chemotherapy (p<0.001). B cells demonstrated particularly dramatic depletion, falling to 5.4% of pre-chemotherapy levels. Levels of all cells recovered to some extent, although B and CD4+ T cells remained significantly depleted even 9 months post-chemotherapy (p<0.001). Phenotypes of repopulating B and CD4+ T cells were significantly different from, and showed no sign of returning to pre-chemotherapy profiles. Repopulating B cells were highly depleted in memory cells, with proportions of memory cells falling from 38% to 10% (p<0.001). Conversely, repopulating CD4+ T cells were enriched in memory cells, which increased from 63% to 75% (p<0.001). Differences in chemotherapy regimen and patient smoking were associated with significant differences in depletion extent or repopulation dynamics. Titres of anti-pneumococcal and anti-tetanus antibodies were both significantly reduced post-chemotherapy and did not recover during the study (p<0.001).
Conclusion: Breast cancer chemotherapy is associated with long-term changes in immune parameters that should be considered during clinical management.
Clinical efficacy of anticancer chemotherapies is dramatically hampered by multidrug resistance (MDR) dependent on inherited traits, acquired defence against toxins, and adaptive mechanisms mounting in tumours. There is overwhelming evidence that molecular events leading to MDR are regulated by redox mechanisms. For example, chemotherapeutics which overrun the first obstacle of redox-regulated cellular uptake channels (MDR1, MDR2, and MDR3) induce a concerted action of phase I/II metabolic enzymes with a temporal redox-regulated axis. This results in rapid metabolic transformation and elimination of a toxin. This metabolic axis is tightly interconnected with the inducible Nrf2-linked pathway, a key switch-on mechanism for upregulation of endogenous antioxidant enzymes and detoxifying systems. As a result, chemotherapeutics and cytotoxic by-products of their metabolism (ROS, hydroperoxides, and aldehydes) are inactivated and MDR occurs. On the other hand, tumour cells are capable of mounting an adaptive antioxidant response against ROS produced by chemotherapeutics and host immune cells. The multiple redox-dependent mechanisms involved in MDR prompted suggesting redox-active drugs (antioxidants and prooxidants) or inhibitors of inducible antioxidant defence as a novel approach to diminish MDR. Pitfalls and progress in this direction are discussed.
The role of the induction of oxidative stress as the mechanism of action of many antitumor drugs is acquiring an increasing interest. In such cases, the antitumor therapy success may be conditioned by the antioxidants present in our own body, which can be synthesized
de novo
(endogenous) or incorporated through the diet and nutritional supplements (exogenous). In this paper, we have reviewed different aspects of antioxidants, including their classification, natural sources, importance in diet, consumption of nutritional supplements, and the impact of antioxidants on health. Moreover, we have focused especially on the study of the interaction between antioxidants and antitumor therapy, considering both radiotherapy and chemotherapy. In this regard, we found that the convenience of administration of antioxidants during cancer treatment still remains a very controversial issue. In general terms, antioxidants could promote or suppress the effectiveness of antitumor treatment and even protect healthy tissues against damage induced by oxidative stress. The effects may depend on many factors discussed in the paper. These factors should be taken into consideration in order to achieve precise nutritional recommendations for patients. The evidence at the moment suggests that the supplementation or restriction of exogenous antioxidants during cancer treatment, as appropriate, could contribute to improving its efficiency.
Background
Outpatient chemotherapy is a core treatment for haematological malignancies; however, its toxicities frequently lead to distressing/potentially life-threatening side-effects (neutropenia/infection, nausea/vomiting, mucositis, constipation/diarrhoea, fatigue). Early detection/management of side-effects is vital to improve patient outcomes, decrease morbidity and limit lengthy/costly hospital admissions. The ability to capture patient-reported health data in real-time, is regarded as the ‘gold-standard’ to allow rapid clinical decision-making/intervention. This paper presents the protocol for a Phase 3 multi-site randomised controlled trial evaluating a novel nurse-led Telehealth intervention for remote monitoring/management of chemotherapy side-effects in Australian haematological cancer patients.
Methods/Design
Two hundred and twenty-two patients will be recruited from two hospitals. Eligibility criteria include: diagnosis of chronic lymphocytic leukaemia/Hodgkin’s/non-Hodgkin’s lymphoma; aged ≥ 18 years; receiving ≥ 2 cycles chemotherapy. Patients will be randomised 1:1 to either the control or intervention arm with stratification by diagnosis, chemotherapy toxicity (high versus low), receipt of previous chemotherapy and hospital. Patients allocated to the control arm will receive ‘Usual Care’ whilst those allocated to the intervention will receive the intervention in addition to ‘Usual Care’. Intervention patients will be provided with a computer tablet and software prompting twice-daily completion of physical/emotional scales for up to four chemotherapy cycles. Should patient data exceed pre-determined limits an Email alert is delivered to the treatment team, prompting nurses to view patient data, and contact the patient to provide clinical intervention. In addition, six scheduled nursing interventions will be completed to educate/support patients in use of the software. Patient outcomes will be measured cyclically (midpoint and end of cycles) via pen-and-paper self-report alongside review of the patient medical record. The primary outcome is burden due to nausea, mucositis, constipation and fatigue. Secondary outcomes include: burden due to vomiting and diarrhoea; psychological distress; ability to self-manage health; level of cancer information/support needs and; utilisation of health services. Analyses will be intention-to-treat. A cost-effectiveness analysis is planned.
Discussion
This trial is the first in the world to test a remote monitoring/management intervention for adult haematological cancer patients receiving chemotherapy. Future use of such interventions have the potential to improve patient outcomes/safety and decrease health care costs by enabling early detection/clinical intervention.
Trial registration
ACTRN12614000516684.
Date registered: 12 March 2014 (registered retrospectively).
Breast cancer is the second leading cause of cancer death in women worldwide and the third most common cancer in India. Various studies have reported that chemotherapy reduces the antioxidant status in patients with cancer. A diet rich in omega-3 fatty acids has been shown to offer protection against breast cancer through various mechanisms. However, there are no reports suggesting a relationship between consumption of omega-3 fatty acids during chemotherapy and antioxidant status in patients with breast cancer. Thus, the objective of this study was to evaluate whether fish oil supplementation could improve the antioxidant status of five women with breast cancer undergoing chemotherapy.
We report on the cases of five Indian women with breast cancer, in the age group of 34 to 60 years, who had poorly differentiated breast carcinoma and underwent modified radical mastectomy. Postsurgery, the patients were given fish oil capsules containing eicosapentaenoic acid (180mg) and docosahexaenoic acid (120mg)/capsule during their chemotherapy. Informed consent was obtained from each participant and they were followed-up to the completion of six chemotherapy cycles at 21-day intervals.
The supplementation of fish oil significantly (p < 0.01) increased superoxide dismutases, glutathione reductase and catalase activity in red blood cells as well as the total plasma antioxidant status in the patients. This approach of using omega-3 fatty acids as an adjuvant treatment for breast cancer may help oncologists to manage the side effects of ongoing chemotherapy by improving the antioxidant status in patients.
Many modalities of cancer therapy induce mechanisms of treatment resistance and escape during chronic treatments, including photodynamic therapy (PDT). It is conceivable that resistance induced by one treatment might be overcome by another treatment. Emerging evidence suggests that the unique mechanisms of tumor cell and microenvironment damage produced by PDT can be utilized to overcome cancer drug resistance, to mitigate compensatory induction of survival pathways and even to re-sensitize resistant cells to standard therapies. Approaches capturing the unique features of PDT, therefore, offer promise for increasing the efficacy of a broad range of therapeutic modalities. Here we highlight key preclinical findings that utilize PDT to overcome classical drug resistance or escape pathways and to enhance the efficacy of many pharmaceuticals possibly explaining clinical observations of PDT response to otherwise treatment resistant disease. With the development of nanotechnology, it is possible that light activation may be used not only to damage and sensitize tumors but also to enable controlled drug release to inhibit escape pathways that may lead to resistance or cell proliferation.
Breast cancer is one of the most common types of cancer among women and one of the
cause of a high mortality rate. Its therapy also causes damage in neoplastic cells. The
aim of this study was to evaluate the oxidative parameters of erythrocytes and
genotoxicity in leukocytes of patients with breast cancer. Oxidative parameters were
detected by spectrophotometry and genotoxic damage by single cell gel electrophoresis.
28 women with breast cancer were monitored before chemotherapy, as well as after the
second and fourth cycle of therapy with cyclophosphamide and doxorubicin. 28 healthy
women were monitored comparative analysis. After the fourth cycle increases (p<0.05)
in the reactive substances to thiobarbituric acid levels, nitrite content and superoxide
dismutase activity were observed, as well as high rates of DNA damage in leukocytes
when compared with the healthy women group and baseline levels. Similarly, after the
second cycle the same parameters were increased (p<0.05) when compared with
baseline levels. An increase (p<0.05) in catalase activity was detected only after the
fourth cycle in comparison with others. Reduced glutathione levels and glutathione
peroxidase activity were decreased (p<0.05) in all cycles when compared with healthy
women, as well as after the second and fourth chemotherapy cycles compared to
baseline. Patients with breast cancer undergoing chemotherapy presented antioxidant
status indicative of oxidative stress before, during and after chemotherapy, as well as
increased genotoxic damage in all stages of treatment, demonstrating the clinical
applicability of evaluated parameters. This clinical study was approved by the Research
Ethics Committee of University Center UNINOVAFAPI (Registration Number:
0406.0.043.00011)
Some chemotherapeutic agents and radiation therapy generate reactive oxygen species (ROS), which diminish the cellular antioxidant capacity, and a ROS level beyond a threshold leads to apoptosis and cancer cell death. Cancer patients take antioxidant supplements widely in order to prevent toxic side effects of chemotherapy and radiation therapy to normal tissues.. However, recent studies have demonstrated that the effects of antioxidant supplementation in cancer therapy were largely disappointing. Despite nearly two decades of research investigating the use of dietary antioxidant supplementation during conventional chemotherapy and radiation therapy, controversy remains about the efficacy and safety of these complementary treatments. Most studies found that antioxidant supplements do not reduce the risk for cancer or prevent tumour growth; at the contrary, these interventions resulted in some cases to be harmful to the patients. There is an urgent need to develop an evidence-based guidance on antioxidant supplementation, in order to obtain the best possible care and to avoid risky treatments for cancer patients.
For more than half a century, the different properties of dexrazoxane have captured the attention of scientists and clinicians. Presently, dexrazoxane is licensed in many parts of the world for two different indications: prevention of cardiotoxicity from anthracycline-based chemotherapy, and prevention of tissue injuries after extravasation of anthracyclines. This article reviews the historical, preclinical, and clinical background for the use of dexrazoxane for these indications.
Cancers have the ability to develop resistance to traditional therapies, and the increasing prevalence of these drug resistant cancers necessitates further research and treatment development. This paper outlines the current knowledge of mechanisms that promote or enable drug resistance, such as drug inactivation, drug target alteration, drug efflux, DNA damage repair, cell death inhibition, and the epithelial-mesenchymal transition, as well as how inherent tumor cell heterogeneity plays a role in drug resistance. It also describes the epigenetic modifications that can induce drug resistance and considers how such epigenetic factors may contribute to the development of cancer progenitor cells, which are not killed by conventional cancer therapies. Lastly, this review concludes with a discussion on the best treatment options for existing drug resistant cancers, ways to prevent the formation of drug resistant cancers and cancer progenitor cells, and future directions of study.
. Cisplatin is a well known platinum-based chemotherapeutic agent used for the treatment of various malignant tumours. A frequent side effect of cisplatin therapy is ototoxicity. Unfortunately, currently there are no available treatments.
Material and Methods
. Experimental, clinical studies and reviews published between 2004 and 2014 in the English medical literature concerning ototoxicity were selected using Medline, PubMed, and Google Scholar databases. Inclusion criteria were cisplatin-induced ototoxicity and therapy aimed at preventing or curing this disorder. Molecular mechanisms and clinical, audiological, and histological markers of cisplatin-induced ototoxicity are described. Moreover, experimental and clinical strategies for prevention or treatment of hearing loss were also reviewed.
Results and Discussion
. Experimental studies demonstrate a wide range of otoprotective molecules and strategies efficient against cisplatin-induced hearing loss. However, only dexamethasone proved a slight otoprotective effect in a clinical study.
Conclusion
. Further research must be completed to bring future therapeutic options into clinical setting.
Despite recent advances in understanding the cancer signaling network and in developing new therapeutic strategies, non-small cell lung cancer (NSCLC) shows poor prognosis and high incidence of recurrence. Insufficient disruption of oncogenic pathways and drug resistance are the most common causes of tumor recurrence. Drug resistance, intrinsic or acquired, represents a major obstacle in the treatment of NSCLC by limiting the efficacy both of conventional chemotherapy and novel biological agents. Therefore, new and more innovative approaches are required for treatment of this cancer. MicroRNAs (miRNAs) are a family of small non-coding RNAs that regulate gene expression by sequence-specific targeting of mRNAs causing translational repression or mRNA degradation. Accumulating evidence suggests that dysregulation of specific miRNAs may be involved in the acquisition of cancer cell resistance to conventional chemotherapy and novel targeted agents by modulating the drug sensitivity of cancer cells. The correction of these miRNAs, using miRNA mimics or antagomiRs, can normalize gene regulatory network and signaling pathways, and optimize anti-cancer therapies by inducing inhibition of cancer cell proliferation and increasing the drug sensitivity. Therefore, miRNA-based gene therapy provides an attractive anti-tumor approach for developing new and more effective individualized therapeutic strategies, improving drug efficiency, and for predicting the response to different anticancer drugs. In this review, we provide an overview on the role of miRNAs in drug resistance mechanisms of NSCLC, discussing the main studies on the alterations in apoptosis, cell cycle and DNA damage repair pathways, as well as in novel drug targets.
Doxorubicin-based chemotherapy represents one of the most effective ways in combating human cancers. However, its clinical use is limited by severe side effects. Selenocystine (SeC) is a natural available selenoamino acid with novel anticancer efficacy. In this study, we used SeC to sensitize HepG2 human hepatocellular carcinoma (HCC) cells to DOX, and to achieve anticancer synergism in vitro and in vivo. Treatment with DOX dose-dependently reduced HepG2 cell viability through initiating cell apoptosis and strong G2/M phase cell cycle arrest. Mechanistic studies indicated that this sensitization of SeC to DOX was achieved by triggering inactivation of ERK and AKT and DNA damage through reactive oxygen species (ROS) overproduction. Pretreatment with inhibitors of ERK and AKT markedly enhanced combined treatment-induced cell killing, indicating that combined treatment-induced HCC cell killing with ERK- and AKT-dependent manner. Furthermore, inhibition of ROS effectively attenuated combined treatment-induced DNA damage and inactivation of ERK and AKT. Additionally, xenograft hepatocellular carcinoma growth was also effectively inhibited by combined treatment through induction of cell apoptosis in vivo. Taken together, our results suggest that the strategy to use SeC and DOX in combination could be a highly efficient way to achieve anticancer synergism against HCC.
The purpose is to examine the effects of melatonin supplementation on sleep, mood, and hot flashes in postmenopausal breast cancer survivors. In a randomized, double-blind, placebo-controlled study, 95 postmenopausal women with a prior history of stage 0-III breast cancer, who had completed active cancer treatment (including hormonal therapy) were randomly assigned 1:1 to either 3 mg oral melatonin (n = 48) or placebo daily (n = 47) for 4 months. Sleep, mood, and hot flashes were assessed at baseline and 4 months via self-administered questionnaire using the Pittsburgh Sleep Quality Index (PSQI), Center for Epidemiologic Studies-Depression (CES-D), and the North Central Cancer Treatment Group (NCCTG) hot flash diary, respectively. Eighty-six women (91 %) completed the study and provided pre- and post-questionnaires. At baseline, 52 % of participants reported poor sleep in the month prior to enrollment. Compared to subjects on placebo, subjects randomized to melatonin experienced significantly greater improvements in subjective sleep quality as measured by the PSQI, including domains on sleep quality, daytime dysfunction and total score. For example, the mean change in PSQI score was -0.1 in the placebo group compared to -1.9 in the melatonin group (p < 0.001). There were no significant differences in measures of depression or hot flashes. Sleep disturbances are common among breast cancer survivors, even after completion of active cancer treatment. This is the first randomized placebo-controlled study among breast cancer survivors to demonstrate that melatonin was associated with an improvement in subjective sleep quality, without any significant adverse effects.
Ascorbate (vitamin C) was an early, unorthodox therapy for cancer, with an outstanding safety profile and anecdotal clinical benefit. Because oral ascorbate was ineffective in two cancer clinical trials, ascorbate was abandoned by conventional oncology but continued to be used in complementary and alternative medicine. Recent studies provide rationale for reexamining ascorbate treatment. Because of marked pharmacokinetic differences, intravenous, but not oral, ascorbate produces millimolar concentrations both in blood and in tissues, killing cancer cells without harming normal tissues. In the interstitial fluid surrounding tumor cells, millimolar concentrations of ascorbate exert local pro-oxidant effects by mediating hydrogen peroxide (H2O2) formation, which kills cancer cells. We investigated downstream mechanisms of ascorbate-induced cell death. Data show that millimolar ascorbate, acting as a pro-oxidant, induced DNA damage and depleted cellular adenosine triphosphate (ATP), activated the ataxia telangiectasia mutated (ATM)/adenosine monophosphate-activated protein kinase (AMPK) pathway, and resulted in mammalian target of rapamycin (mTOR) inhibition and death in ovarian cancer cells. The combination of parenteral ascorbate with the conventional chemotherapeutic agents carboplatin and paclitaxel synergistically inhibited ovarian cancer in mouse models and reduced chemotherapy-associated toxicity in patients with ovarian cancer. On the basis of its potential benefit and minimal toxicity, examination of intravenous ascorbate in combination with standard chemotherapy is justified in larger clinical trials.
Wear debris associated periprosthetic osteolysis represents a major pathological process associated with the aseptic loosening of joint prostheses. Naringin is a major flavonoid identified in grapefruit. Studies have shown that naringin possesses many pharmacological properties including effects on bone metabolism. The current study evaluated the influence of naringin on wear debris induced osteoclastic bone resorption both in vitro and in vivo. The osteoclast precursor cell line RAW 264.7 was cultured and stimulated with polymethylmethacrylate (PMMA) particles followed by treatment with naringin at several doses. Tartrate resistant acid phosphatase (TRAP), calcium release, and gene expression profiles of TRAP, cathepsin K, and receptor activator of nuclear factor-kappa B were sequentially evaluated. PMMA challenged murine air pouch and the load bearing tibia titanium pin-implantation mouse models were used to evaluate the effects of naringin in controlling PMMA induced bone resorption. Histological analyses and biomechanical pullout tests were performed following the animal experimentation. The in vitro data clearly demonstrated the inhibitory effects of naringin in PMMA induced osteoclastogenesis. The naringin dose of 10 μg/mL exhibited the most significant influence on the suppression of TRAP activities. Naringin treatment also markedly decreased calcium release in the stimulated cell culture medium. The short-term air pouch mouse study revealed that local injection of naringin ameliorated the PMMA induced inflammatory tissue response and subsequent bone resorption. The long-term tibia pin-implantation mouse model study suggested that daily oral gavage of naringin at 300 mg/kg dosage for 30 days significantly alleviated the periprosthetic bone resorption. A significant increase of periprosthetic bone volume and regaining of the pin stability were found in naringin treated mice. Overall, this study suggests that naringin may serve as a potential therapeutic agent to treat wear debris associated osteolysis.
Chemotherapy-induced peripheral neuropathy is frequently a dose-limiting factor in cancer treatment and may cause pain and irreversible function loss in cancer survivors. We tested whether alpha-lipoic acid (ALA) could decrease the severity of peripheral neuropathy symptoms in patients undergoing platinum-based chemotherapy.
Cancer patients 18 years or older were randomly selected to receive either 600 mg ALA or a placebo three times a day orally for 24 weeks while receiving chemotherapy regimens including cisplatin or oxaliplatin. Neuropathy was measured by the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) scale and the NCI Common Toxicity Criteria for Adverse Events neurotoxicity grades. Results from timed functional tests and the Brief Pain Inventory (BPI) were secondary endpoints.
Seventy of 243 (29 %) patients completed the study (24 weeks). Both the ALA and the placebo arms had a comparable drop-out rate. No statistically significant differences were found between the ALA and the placebo groups for FACT/GOG-Ntx scores, BPI scores, and patients' functional outcomes.
This strategy of oral ALA administration was ineffective at preventing neurotoxicity caused by oxaliplatin or cisplatin. High attrition rates due to poor patient compliance and manner of dosage administration in this trial demonstrated a lack of feasibility for this intervention. Future studies to explore ALA as a neuroprotective agent should take heed of the barriers confronted in this study.
In the era of new and mostly effective therapeutic protocols, multiple myeloma still tends to be a hard-to-treat hematologic cancer. This hallmark of the disease is in fact a sequel to drug resistant phenotypes persisting initially or emerging in the course of treatment. Furthermore, the heterogeneous nature of multiple myeloma makes treating patients with the same drug challenging because finding a drugable oncogenic process common to all patients is not yet feasible, while our current knowledge of genetic/epigenetic basis of multiple myeloma pathogenesis is outstanding. Nonetheless, bone marrow microenvironment components are well known as playing critical roles in myeloma tumor cell survival and environment-mediated drug resistance happening most possibly in all myeloma patients. Generally speaking, however; real mechanisms underlying drug resistance in multiple myeloma are not completely understood. The present review will discuss the latest findings and concepts in this regard. It reviews the association of important chromosomal translocations, oncogenes (e.g. TP53) mutations and deranged signaling pathways (e.g. NFκB) with drug response in clinical and experimental investigations. It will also highlight how bone marrow microenvironment signals (Wnt, Notch) and myeloma cancer stem cells could contribute to drug resistance in multiple myeloma.
Oxaliplatin, the third-generation platinum compound, has evolved as one of the most important therapeutic agents in colorectal cancer chemotherapy. The main limiting factor in oxaliplatin treatment is painful neuropathy that is difficult to treat. This side effect has been studied for several years, but its full mechanism is still inconclusive, and effective treatment does not exist. Data suggest that oxaliplatin's initial neurotoxic effect is peripheral and oxidative stress-dependent. A spinal target is also suggested in its mechanism of action. The flavonoids rutin and quercetin have been described as cell-protecting agents because of their antioxidant, antinociceptive, and anti-inflammatory actions. We proposed a preventive effect of these agents on oxaliplatin-induced painful peripheral neuropathy based on their antioxidant properties.
Oxaliplatin (1 mg/kg, i.v.) was injected in male Swiss mice, twice a week (total of nine injections). The development of sensory alterations, such as thermal and mechanical allodynia, was evaluated using the tail immersion test in cold water (10[degree sign]C) and the von Frey test. Rutin and quercetin (25-100 mg/kg, i.p.) were injected 30 min before each oxaliplatin injection. The animals' spinal cords were removed for histopathological and immunohistochemical evaluation and malondialdehyde assay.
Oxaliplatin significantly increased thermal and mechanical nociceptive response, effects prevented by quercetin and rutin at all doses. Fos immunostaining in the dorsal horn of the spinal cord confirmed these results. The oxidative stress assays mainly showed that oxaliplatin induced peroxidation in the spinal cord and that rutin and quercetin decreased this effect. The flavonoids also decreased inducible nitric oxide synthase and nitrotyrosine immunostaining in the dorsal horn of the spinal cord. These results suggest that nitric oxide and peroxynitrite are also involved in the neurotoxic effect of oxaliplatin and that rutin and quercetin can inhibit their effect in the spinal cord. We also observed the preservation of dorsal horn structure using histopathological analyses.
Oxaliplatin induced painful peripheral neuropathy in mice, an effect that was prevented by rutin and quercetin. The mechanism of action of oxaliplatin appears to be, at least, partially oxidative stress-induced damage in dorsal horn neurons, with the involvement of lipid peroxidation and protein nitrosylation.
In recent years, drug delivery systems (DDS) have been developed, along with anticancer agents for those systems based on the concept of achieving a better clinical response and tolerability. Several clinical trials have shown that these drugs have better clinical effects in the treatment of many cancers, leading to their expanded indications. Liposomal doxorubicin is one DDS agent used to treat AIDS-related Kaposi's sarcoma and ovarian cancer in Japan. In addition to those two indications, the Food and Drug Administration (FDA) approved this drug for the treatment of multiple myeloma in 2007. Another DDS agent approved in Japan is nanoparticle albumin-bound paclitaxel, which has been used in the treatment of breast cancer. Most recently, this drug has been approved for the treatment of non-small cell lung cancer in the U.S.A. Although these DDS agents appear to be less toxic than conventional drugs, DDS-specific side effects such as various skin reactions, hypersensitivity reaction, and peripheral neuropathy sometimes occur. Therefore, medical staff must understand DDS anticancer agents fully, including characteristic side effects, to achieve the desired clinical outcomes.
Cancer drug resistance continues to be a major impediment in medical oncology. Clinically, resistance can arise prior to or as a result of cancer therapy. In this review, we discuss different mechanisms adapted by cancerous cells to resist treatment, including alteration in drug transport and metabolism, mutation and amplification of drug targets, as well as genetic rewiring which can lead to impaired apoptosis. Tumor heterogeneity may also contribute to resistance, where small subpopulations of cells may acquire or stochastically already possess some of the features enabling them to emerge under selective drug pressure. Making the problem even more challenging, some of these resistance pathways lead to multidrug resistance, generating an even more difficult clinical problem to overcome. We provide examples of these mechanisms and some insights into how understanding these processes can influence the next generation of cancer therapies.
Diazinon (DZN) is one of the most widely used insecticides in agricultural pest control. Previous studies have shown that DZN may induce hepatotoxicity. Reactive oxygen species and apoptosis pathways are involved in the toxicity of DZN. Crocin, a constituent of saffron, has hepatoprotective effects due to its antioxidant activity. In this study, we examined the effects of subacute DZN exposure and ameliorating effect of crocin on lipid peroxidation and pathological changes in rat liver. Moreover, protein levels of activated and total caspases-3 and -9 and Bax/Bcl-2 ratio were measured. Five groups of rats were used in the experiment. Corn oil (control), DZN (15 mg/kg per day, orally) and crocin (12.5, 25 and 50 mg/kg per day, intraperitoneally in combination with DZN) were given to male Wistar rats (n = 6) for 4 weeks. The level of malondialdehyde (MDA) increased significantly in DZN group compared with the control group (p < 0.05). MDA level decreased significantly in the group that received DZN plus 25 mg crocin (p < 0.001). No gross or histological evidence of treatment-related damage to the liver after oral exposure to DZN was observed. DZN also induced apoptosis through activation of caspases-9 and -3 and increasing Bax/Bcl-2 ratio. Crocin attenuated the activation of caspases and reduced the Bax/Bcl-2 ratio. It is concluded that subacute exposure to DZN induces oxidative stress-mediated apoptosis and crocin may reduce DZN-induced hepatotoxicity.
Background:
Treatment for pancreatic cancer with pharmacological ascorbate (ascorbic acid, vitamin C) decreases tumor progression in preclinical models. A phase I clinical trial was performed to establish safety and tolerability of pharmacological ascorbate combined with gemcitabine in patients with biopsy-proven stage IV pancreatic adenocarcinoma.
Design:
Nine subjects received twice-weekly intravenous ascorbate (15-125 g) employing Simon's accelerated titration design to achieve a targeted post-infusion plasma level of ≥350 mg/dL (≥20 mM). Subjects received concurrent gemcitabine. Disease burden, weight, performance status, hematologic and metabolic laboratories, time to progression and overall survival were monitored.
Results:
Mean plasma ascorbate trough levels were significantly higher than baseline (1.46 ± 0.02 vs. 0.78 ± 0.09 mg/dL, i.e., 83 vs. 44 μM, p < 0.001). Adverse events attributable to the drug combination were rare and included diarrhea (n = 4) and dry mouth (n = 6). Dose-limiting criteria were not met for this study. Mean survival of subjects completing at least two cycles (8 weeks) of therapy was 13 ± 2 months.
Conclusions:
Data suggest pharmacologic ascorbate administered concurrently with gemcitabine is well tolerated. Initial data from this small sampling suggest some efficacy. Further studies powered to determine efficacy should be conducted.
Expression of the MRP1 gene encoding the GS-X pump and of the γ-GCSh gene encoding the heavy (catalytic) subunit of the γ-glutamylcysteine synthetase is frequently elevated in many drug-resistant
cell lines and can be co-induced by many cytotoxic agents. However, mechanisms that regulate the expression of these genes
remain to be elucidated. We report here that like γ-GCSh, the expression of MRP1 can be induced in cultured cells treated with pro-oxidants such astert-butylhydroquinone, 2,3-dimethoxy-1,4-naphthoquinone, and menadione. Intracellular reactive oxygen intermediate (ROI) levels
were increased in hepatoma cells treated withtert-butylhydroquinone for 2 h as measured by flow cytometry using an ROI-specific probe, dihydrorhodamine 123. Elevated GSH levels
in stably γ-GCSh-transfected cell lines down-regulated endogenous MRP1 and γ-GCShexpression. ROI levels in these transfected cells were lower than those in the untransfected control. In the cell lines in
which depleting cellular GSH pools did not affect the expression of theMRP1 and γ-GCSh genes, only minor increased intracellular levels of ROIs were observed. These results suggest that intracellular ROI levels
play an important role in the regulation ofMRP1 and γ-GCSh expression. Our data also suggest that elevated intracellular GSH levels not only facilitate substrate transport by the MRP1/GS-X
pump as previously demonstrated, but also suppress MRP1 and γ-GCShexpression.
The effect of various doses (0, 10, 20, 40, or 80 mg/kg body weight) of naringin (a citrus flavonone) was studied on streptozotocin (STZ)-induced hyperglycaemic rats to evaluate the possible hypoglycaemic and antioxidant activity of naringin in diabetes. In comparison to the normoglycaemic group the treatment of rats with a single dose of STZ (65 mg/kg body weight) only revealed a significant increase (P < 0.05) in plasma hydrogen peroxide (H2O2) by 230%, increased the thiobarbituric acid reactive substances (TBARS) as index of the lipid peroxidation level by 69%, while total antioxidant activity was decreased by 36%, with a consistent significant decrease (P < 0.05) in the activity of erythrocytes antioxidative enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and paraoxonase (PON). Exogenous administration of individual gradual doses of naringin to hyperglycaemic rats causes a dose-dependent decrease of the glucose level, an increase of the insulin concentration, a decrease of the H2O2 and TBARS levels, as well as the increase of the total antioxidant status with an increase of antioxidant enzyme activities (CAT, SOD, GPx, and PON). From this study, it may be concluded that all doses of naringin provided a significant amelioration of hypoglycaemic and antioxidant activity in STZ-induced diabetic rats, however, the greatest effect of naringin was observed at 80 mg/kg body weight.
Malignant cells utilize diverse strategies that enable them to thrive under adverse conditions while simultaneously inhibiting the development of anti-tumor immune responses. Hostile microenvironmental conditions within tumor masses, such as nutrient deprivation, oxygen limitation, high metabolic demand, and oxidative stress, disturb the protein-folding capacity of the endoplasmic reticulum (ER), thereby provoking a cellular state of “ER stress.” Sustained activation of ER stress sensors endows malignant cells with greater tumorigenic, metastatic, and drug-resistant capacity. Additionally, recent studies have uncovered that ER stress responses further impede the development of protective anti-cancer immunity by manipulating the function of myeloid cells in the tumor microenvironment. Here, we discuss the tumorigenic and immunoregulatory effects of ER stress in cancer, and we explore the concept of targeting ER stress responses to enhance the efficacy of standard chemotherapies and evolving cancer immunotherapies in the clinic.
Introduction:
Pancreatic ductal adenocarcinoma (PDA) is characterized by expression of oncogenic KRas which drives all aspects of tumorigenesis. Oncogenic KRas induces the formation of reactive oxygen species (ROS) which have been implicated in initiation and progression of PDA. To facilitate tumor promoting levels and to avoid oncogene-induced senescence or cytotoxicity, ROS homeostasis in PDA cells is balanced by additional up-regulation of antioxidant systems. Areas Covered: We examine the sources of ROS in PDA, the mechanisms by which ROS homeostasis is maintained, and the biological consequences of ROS in PDA. Additionally, we discuss the potential mechanisms for targeting ROS homoeostasis as a point of therapeutic intervention. An extensive review of the relevant literature as it relates to the topic was conducted using PubMed. Expert Commentary: Even though oncogenic mutations in the KRAS gene have been detected in over 95% of human pancreatic adenocarcinoma, targeting its gene product, KRas, has been difficult. The dependency of PDA cells on balancing ROS homeostasis could be an angle for new prevention or treatment strategies. These include use of antioxidants to prevent formation or progression of precancerous lesions, or methods to increase ROS in tumor cells to toxic levels.
Reactive oxygen species (ROS), now appreciated for their cellular signaling capabilities, have a dual role in cancer. On the one hand, ROS can promote protumorigenic signaling, facilitating cancer cell proliferation, survival, and adaptation to hypoxia.Onthe other hand, ROS can promote antitumorigenic signaling and trigger oxidative stress–induced cancer cell death. To hyperactivate the cell signaling pathways necessary for cellular transformation and tumorigenesis, cancer cells increase their rate of ROS production compared with normal cells. Concomitantly, in order to maintain ROS homeostasis and evade cell death, cancer cells increase their antioxidant capacity. Compared with normal cells, this altered redox environment of cancer cells may increase their susceptibility to ROS-manipulation therapies. In this review, we discuss the two faces of ROS in cancer, the potential mechanisms underlying ROS signaling and the opposing cancer therapeutic approaches to targeting ROS. Expected final online publication date for the Annual Review of Cancer Biology Volume 1 is March 04, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
The beneficial effect of saffron has been recognized since ancient times. Scientists have attributed its healthy benefits to its antioxidant properties; however, the nutrigenomics of saffron are poorly understood. Here, we have investigated the effect of aqueous extract of saffron (AES) on human vascular endothelial cells (HUVECs) under oxidative stress induced by free radical generators; 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH) and tert-butylhydroperoxide (TBHP). The biocompatibility, the protective effect on DNA damage, and the AES ability to neutralize reactive oxygen species (ROS) were evaluated. Furthermore, the modulation of cell signalling pathways by saffron was studied. The results showed that saffron not only acts as a direct antioxidant agent but as a modulator of micro-RNAs (mir-21 and mir142-3p) and RNAs profile (PTEN/AKT1) on HUVECs under stress conditions. Ultimately, the modulation of signalling pathways by saffron improves cell survival and provides a therapeutic approach in the prevention and treatment of oxidative stress mediated diseases.
To survive inhospitable environments, tumor cells are forced to remodel their signaling pathways by altering transcription, translation, and post-translational modifications. This adaptation is regulated in a spatial and temporal manner and gives rise to individual tumor cells with distinct gene expression and metabolic signatures. Such phenotypic heterogeneity is the result of tumor cell plasticity, which–together with the genetic background of the tumor–determines whether cells resist environmental stress, enter dormancy, or metastasize. This review summarizes our understanding of how tumor cells exploit the cellular stress response to balance proliferation, differentiation, and survival signals, as well as to remodel local and distant environments. We focus in particular on tumor metastasis, which is the greatest impediment to clinical management of cancers today.
Coenzyme Q10, (CoQ10) an electron transporter and an antioxidant, protects a variety of cell types against oxidative stress and apoptosis. However, protective effect of CoQ10 on oxidative stress-induced apoptosis in lymphocytes has not been studied in detail. In this study, we investigated the effect of CoQ10 on oxidative stress-induced apoptosis in lymphocytes. An exposure of peripheral blood lymphocytes to oxidative stressors, rotenone or hydrogen peroxide, lead to apoptosis. Pre-treatment of lymphocytes with CoQ10 resulted in a significantly reduced level of oxidative stress-induced apoptosis, which was associated with decreased reactive oxygen species production, an inhibition of mitochondrial membrane depolarization, and inhibition of activation of caspase-9 and caspase-3. Furthermore, CoQ10 inhibited oxidative stress induced apoptosis in both CD4+ T, and CD8+ T, and CD19+ B cells. Our findings suggest that CoQ10 may provide new therapeutic strategies for preventing oxidative stress-induced cell death and dysfunction in lymphocytes and lymphocyte subsets.
Tumor cells are often exposed to intrinsic and external factors that alter protein homeostasis, thus producing endoplasmic reticulum (ER) stress. To cope with this, cells evoke an adaptive mechanism to restore ER proteostasis known as the unfolded protein response (UPR). The three main UPR signaling branches initiated by IRE1α, PERK, and ATF6 are crucial for tumor growth and aggressiveness as well as for microenvironment remodeling or resistance to treatment. We provide a comprehensive overview of the contribution of the UPR to cancer biology and the acquisition of malignant characteristics, thus highlighting novel aspects including inflammation, invasion and metastasis, genome instability, resistance to chemo/radiotherapy, and angiogenesis. The therapeutic potential of targeting ER stress signaling in cancer is also discussed
Astaxanthin has been demonstrated to exhibit a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. However, the molecular mechanism of astaxanthin-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Rad51 plays a central role in homologous recombination, and studies show that chemo-resistant carcinomas exhibit high levels of Rad51 expression. In this study, astaxanthin treatment inhibited cell viability and proliferation of two NSCLC cells, A549 and H1703. Astaxanthin treatment (2.5-20 μM) decreased Rad51 expression and phospho-AKT(Ser473) protein level in a time and dose-dependent manner. Furthermore, expression of constitutively active AKT (AKT-CA) vector rescued the decreased Rad51 mRNA and protein levels in astaxanthin-treated NSCLC cells. Combined treatment with phosphatidylinositol 3-kinase (PI3K) inhibitors (LY294002 or wortmannin) further decreased the Rad51 expression in astaxanthin-exposed A549 and H1703 cells. Knockdown of Rad51 expression by transfection with si-Rad51 RNA or cotreatment with LY294002 further enhanced the cytotoxicity and cell growth inhibition of astaxanthin. Additionally, Mitomycin C (MMC) as an anti-tumor antibiotic is widely used in clinical NSCLC chemotherapy. Combination of MMC and astaxanthin synergistically resulted in cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced phospho-AKT(Ser473) level and Rad51 expression. Overexpression of AKT-CA or Flag-tagged Rad51 reversed the astaxanthin and MMC-induced synergistic cytotoxicity. In contrast, pretreatment with LY294002 further decreased the cell viability in astaxanthin and MMC co-treated cells. In conclusion, astaxanthin enhances MMC-induced cytotoxicity by decreasing Rad51 expression and AKT activation. These findings may provide rationale to combine astaxanthin with MMC for the treatment of NSCLC.
The role of reactive oxygen species (ROS) in cancer cells has been intensively studied for the past two decades. Cancer cells mostly have higher basal ROS levels than their normal counterparts. The induction of ROS has been shown to be associated with cancer development, metastasis, progression, and survival. Various therapeutic approaches targeting intracellular ROS levels have yielded mixed results. As widely accepted dietary supplements, antioxidants demonstrate both ROS scavenging ability and anti-cancer characteristics. However, antioxidants may not always be safe to use since excessive intake of antioxidants could lead to serious health concerns. In this review, we have evaluated the production and scavenging systems of ROS in cells, as well as the beneficial and harmful roles of ROS in cancer cells. We also examine the effect of antioxidants in cancer treatment, the effect of combined treatment of antioxidants with traditional cancer therapies, and the side effects of excessive antioxidant intake.
Copyright © 2015. Published by Elsevier Ireland Ltd.
Consumption of tomatoes and tomato products has been shown to provide nutritional and health benefits.
Naringin is a flavonoid found in grapefruit and other citrus fruits that shows antioxidant activity. The aim of the present study was to determine the anti-genotoxic and protective effects of naringin on the chemotherapeutic/radiomimetic agent bleomycin (BLM) in human blood lymphocyte cultures in vitro using micronucleus test and chromosomal aberrations (CA) assay. We tested the three doses of naringin (1, 2, 3 µg/mL) and a single dose of BLM (20 µg/mL). BLM significantly increased the total CAs and micronucleus frequency at a concentration of 20 µg/mL. Naringin did not show any toxicity in doses of 1, 2, and 3 µg/mL. Combined treatments of BLM and naringin (2 and 3 µg/mL) significantly reduced micronucleus formation. Naringin dose-dependently decreased the total chromosome aberrations frequency induced by BLM. These results indicate that naringin could prevent BLM (20 µg/mL)-induced genotoxicity.
Recent studies indicate that Traditional Chinese medicine (TCM) can play an important role in the whole course of cancer treatment such as recovery stages of post-operative, radiotherapy or chemotherapy stages instead of only terminal stage of cancer. In this review, we have summarized current evidence for using TCM as adjuvant cancer treatment in different stages of cancer lesions. Some TCMs (e.g., TJ-41, Liu-jun-zi-tang, PHY906, Coumarin, and Aescine) are capable of improving the post-operative symptoms such as fatigue, pain, appetite, diarrhea, nausea, vomiting, and lymphedema. Some TCMs (e.g., Ginseng, Huang-Qi, BanZhiLian, TJ-48, Huachansu injection, Shenqi fuzheng injection, and Kanglaite injection) in combination with chemo- or radio-therapy are capable of enhancing the efficacy of and diminishing the side effects and complications caused by chemo- and radiotherapy. Taken together, they have great advantages in terms of suppressing tumor progression, relieving surgery complications, increasing the sensitivity of chemo- and radio- therapeutics, improving an organism's immune system function, and lessening the damage caused by surgery, chemo- or radio-therapeutics. They have significant effects on relieving breast cancer-related lymphedema, reducing cancer-related fatigue and pain, improving radiation pneumonitis and gastrointestinal side effects, protecting liver function, and even ameliorating bone marrow suppression. This review of those medicines should contribute to an understanding of Chinese herbal medicines as an adjunctive therapy in the whole course of cancer treatment instead of only terminal stage of cancer, by providing useful information for development of more effective anti-cancer drugs and making more patients "survival with cancer" for a long time.
Cancer cells are characterized by an increase in the rate of reactive oxygen species (ROS) production and an altered redox environment compared to normal cells. Furthermore, redox regulation and redox signaling play a key role in tumorigenesis and in the response to cancer therapeutics. ROS have contradictory roles in tumorigenesis, which has important implications for the development of potential anticancer therapies that aim to modulate cellular redox levels. ROS play a causal role in tumor development and progression by inducing DNA mutations, genomic instability, and aberrant pro-tumorigenic signaling. On the other hand, high levels of ROS can also be toxic to cancer cells and can potentially induce cell death. To balance the state of oxidative stress, cancer cells increase their antioxidant capacity, which strongly suggests that high ROS levels have the potential to actually block tumorigenesis. This fact makes pro-oxidant cancer therapy an interesting area of study. In this review, we discuss the controversial role of ROS in tumorigenesis and especially elaborate on the advantages of targeting ROS scavengers, hence the antioxidant capacity of cancer cells, and how this can be utilized for cancer therapeutics.
Multi-drug resistance (MDR) has become the largest obstacle to the success of cancer chemotherapies. The mechanisms of MDR and the approaches to test MDR have been discovered, yet not fully understood. This review covers the in vivo and in vitro approaches for the detection of MDR in the laboratory and the mechanisms of MDR in cancers. This study also envisages the future developments toward the clinical and therapeutic applications of MDR in cancer treatment. Future therapeutics for cancer treatment will likely combine the existing therapies with drugs originated from MDR mechanisms such as anti-cancer stem cell drugs, anti-miRNA drugs or anti-epigenetic drugs. The challenges for the clinical detection of MDR will be to find new biomarkers and to determine new evaluation systems before the drug resistance emerges.
Fatigue is a common, often debilitating, side effect of cancer chemotherapy. Pharmacologic vitamin C has been used as an alternative treatment for the disease itself but its effects on fatigue have not often been documented. Here we report on the case of a woman with recurrent breast cancer, undergoing weekly chemotherapy, with lethargy as a major symptom. Vitamin C (50 g/session) was administered twice weekly and quality of life and multidimensional fatigue symptomology questionnaires were undertaken. Dramatic decreases in fatigue and insomnia were observed, as well as increased cognitive functioning. There were no adverse side effects of i.v. vitamin C.
Increased consumption of fruit and vegetables can represent an easy strategy to significantly reduce the incidence of cancer. We recently demonstrated that the flavonoid quercetin, naturally present in the diet and belonging to the class of phytochemicals, is able to sensitize several leukemia cell lines and B cells isolated from patients affected by chronic lymphocytic leukemia (B-CLL), in addition to apoptotic inducers (anti-CD95 and rTRAIL). Further, it potentiates the effect of fludarabine, a first-line chemotherapeutic drug used against CLL. The proapoptotic activity of quercetin in cell lines and B-CLL is related to the expression and activity of Mcl-1-antiapoptotic proteins belonging to the Bcl-2 family. Quercetin downregulates Mcl-1 mRNA and protein levels acting on mRNA stability and protein degradation. Considering the low toxicity of the flavonoids toward normal peripheral blood cells, our experimental results are in favor of a potential use of quercetin in adjuvant chemotherapy in CLL or other types of cancer.
Many patients being treated for cancer use dietary supplements, particularly antioxidants, in the hope of reducing the toxicity of chemotherapy and radiotherapy. Some researchers have claimed, furthermore, that antioxidants also increase the effectiveness of cytotoxic therapy and have explicitly recommended their use. However, mechanistic considerations suggest that antioxidants might reduce the effects of conventional cytotoxic therapies. Preclinical data are currently inconclusive and a limited number of clinical studies have not found any benefit. Clinicians should advise their patients against the use of antioxidant dietary supplements during chemotherapy or radiotherapy. Such caution should be seen as the standard approach for any unproven agent that may be harmful.