Demethylating agent 5-aza-2-deoxycytidine enhances susceptibility of breast cancer cells to anticancer agents.
DNA methylation plays an important role in regulation of gene expression and is increasingly being recognized as a determinant of chemosensitivity of human cancers. With the aim of improving the chemotherapeutic efficacy of breast carcinoma, the effect of DNA methyltransferase inhibitor, 5-Aza-2'-deoxycytidine (5-aza-CdR), on the chemosensitivity of anticancer drugs was investigated. The cytotoxicity of paclitaxel (PTX), adriamycin (ADR), and 5-fluorouracil (5-FU) was analyzed against human breast cancer cell lines, MDA MB 231 and MCF 7 cell lines using the MTT assay, and the synergy of 5-aza-CdR and these agents was determined by Drewinko's fraction method. The effects of each single agent or the combined treatment on cell cycle arrest were analyzed by flow cytometric analysis. We also investigated the effect of each single agent or the combined treatment of anticancer drugs with 5-aza-CdR on the methylation status of the selected genes by methylation specific PCR. In MDA MB 231 cells, a synergistic antiproliferative effect was observed with a combination of 10 microM 5-aza-CdR and these three anticancer drugs, while in MCF 7 cells, a semiadditive effect was observed. Treatment with 5-aza-CdR and anticancer drug resulted in partial demethylation of a panel of genes including RARbeta2, Slit2, GSTP1, and MGMT. Based on these findings, we propose that 5-aza-CdR enhances the chemosensitivity of anticancer drugs in breast cancer cells and may be a promising approach for increasing the chemotherapeutic potential of these anticancer agents for more effective management of breast carcinomas.
Mirza
Sameer
S
Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
Sharma
Gayatri
G
Pandya
Pranav
P
Ralhan
Ranju
R
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D049109:Cell Proliferation; D019175:DNA Methylation / Q000187:drug effects; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors*; D000077209:Decitabine; D004317:Doxorubicin / Q000494:pharmacology; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured / Q000187:drug effects
D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D000077209:Decitabine; D004317:Doxorubicin; D015254:DNA Modification Methylases; D001374:Azacitidine; D017239:Paclitaxel; D005472:Fluorouracil
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