ABSTRACT
PURPOSE: The DNA methylation mediated by specific DNA methyltransferases (DNMTs), results in the epigenetic silencing of multiple genes which are implicated in human breast cancer. We hypothesized that the natural compounds modulate the expression of DNMTs and their associated proteins in the breast cancer cell lines and affect the methylation mediated gene silencing. METHODS: The DNMTs transcript expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in the tumors and the adjacent normal breast tissues of the patients with invasive ductal breast carcinoma. We tested the hypothesis that the natural compounds, viz., epigallocatechin gallate (EGCG), genistein, withaferin A, curcumin, resveratrol, and guggulsterone, have demethylation potential. To investigate this hypothesis, we analyzed the DNMTs expression at the transcript levels, followed by the analysis of DNMT1 and its associated proteins (HDAC1, MeCP2, and MBD2). RESULTS: The increased DNMTs transcripts expression, viz., DNMT1, DNMT3a, and DNMT3b, in the breast cancer tissues suggest involvement of the DNMTs in the breast carcinogenesis. Quantitative RT-PCR analysis revealed that the treatment with natural compounds, viz., EGCG, genistein, withaferin A, curcumin, resveratrol, and guggulsterone, resulted in a significant decrease in the transcript levels of all the DNMTs investigated. Importantly, these natural compounds decreased the protein levels of DNMT1, HDAC1, and MeCP2. CONCLUSION: Our results demonstrate that the natural compounds, EGCG, genistein, withaferin A, curcumin, resveratrol, and guggulsterone, have the potential to reverse the epigenetic changes. Moreover, their lack of toxicity makes these natural compounds promising candidates for the chemoprevention of the breast cancer. In-depth future mechanistic studies aimed to elucidate how these compounds affect the gene transcription are warranted.
Subject(s)
Humans , Breast , Breast Neoplasms , Catechin , Cell Line , Chemoprevention , Curcumin , DNA , DNA Methylation , Epigenomics , Genistein , Methylation , Methyltransferases , Pregnenediones , Proteins , Stilbenes , WithanolidesABSTRACT
Background: Breast cancer is the most common cancer in Indian women. The aim of this study was to assess the levels of red blood cell (RBC) superoxide dismutase (r-SOD), RBC catalase (r-CAT), RBC glutathione peroxidase (r-GPx) and the ferric reducing ability of plasma (FRAP) in advanced breast cancer patients post mastectomy before and after chemotherapy. Methods: Female breast cancer patients between 27 and 65 years of age who were admitted to the Department of Surgery of the All India Institute of Medical Sciences in New Delhi were enrolled in the study. This study included two arms: a control group of healthy age-matched females (n=20) and patients undergoing treatment with a combination of the anticancer drugs cyclophosphamide, doxorubicin, and 5-fluorouracil (CAF) (n=55), No treatment was given to the control group. The CAF group received CAF treatment at weeks 0, 3, and 6, then surgery at week 9 followed by CAF treatment at weeks 12, 15, and 18. A three-week drug-free interval was included between each cycle of drug treatment. Blood samples were collected from control subjects and from patients in the CAF group before administration of drugs at week zero to establish a baseline, again weeks 12 and 18, and once more at the end of the 26-week treatment. Blood samples collected from the control subjects and CAF patients were analysed to determine levels of the endogenous antioxidants, r-SOD, r-CAT, r-GPx, and FRAP. Results: Levels of r-SOD, r-CAT, r-GPx, and FRAP in CAF-treated patients at 12, 18, and 26 weeks were significantly decreased (P<0.001) in comparison to the baseline levels observed at week zero. Conclusion: The results from the present study show that a change in the enzyme antioxidant systems in patients after chemotherapy and mastectomy causes an overall decrease in antioxidant levels. Chemotherapeutic agents induce oxidative stress that damages many cellular targets.