title: Demethylating agent 5-aza-2-deoxycytidine enhances susceptibility of breast cancer cells to anticancer agents.
abstract: 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.
authors.affiliation: Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
authors.forename: Sameer
authors.initials: S
authors.lastname: Mirza
authors.forename: Gayatri
authors.initials: G
authors.lastname: Sharma
authors.forename: Pranav
authors.initials: P
authors.lastname: Pandya
authors.forename: Ranju
authors.initials: R
authors.lastname: Ralhan
mesh_terms: 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
chemical_list: D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D000077209:Decitabine; D004317:Doxorubicin; D015254:DNA Modification Methylases; D001374:Azacitidine; D017239:Paclitaxel; D005472:Fluorouracil
references.citation: Cancer Biochem Biophys. 1976 May;1(4):187-95
references.pmid: 975020
references.citation: Cancer Res. 2001 Mar 15;61(6):2782-7
references.pmid: 11289162
references.citation: Anticancer Drugs. 2004 Feb;15(2):161-7
references.pmid: 15075673
references.citation: Oncol Rep. 2005 Oct;14(4):975-9
references.pmid: 16142360
references.citation: Proc Natl Acad Sci U S A. 1995 Aug 29;92(18):8493-7
references.pmid: 7667317
references.citation: J Immunol. 1995 Sep 1;155(5):2311-7
references.pmid: 7650367
references.citation: Oncogene. 2004 Sep 2;23(40):6779-87
references.pmid: 15273730
references.citation: Cancer Res. 2002 Oct 15;62(20):5874-80
references.pmid: 12384551
references.citation: N Engl J Med. 2008 Mar 13;358(11):1148-59
references.pmid: 18337604
references.citation: Cancer Sci. 2006 Sep;97(9):938-44
references.pmid: 16805821
references.citation: Oncol Rep. 2004 Sep;12(3):509-16
references.pmid: 15289829
references.citation: Eur J Nucl Med Mol Imaging. 2004 Jun;31 Suppl 1:S149-61
references.pmid: 15107948
references.citation: J Natl Cancer Inst. 2000 Aug 16;92(16):1303-7
references.pmid: 10944551
references.citation: World J Gastroenterol. 2005 Apr 7;11(13):2022-5
references.pmid: 15800999
references.citation: Biochem Biophys Res Commun. 2001 Mar 9;281(4):866-71
references.pmid: 11237739
references.citation: CA Cancer J Clin. 2008 Mar-Apr;58(2):71-96
references.pmid: 18287387
references.citation: Front Biosci. 2005 May 01;10:1897-931
references.pmid: 15769674
references.citation: Leuk Res. 2004 Dec;28(12):1267-71
references.pmid: 15475067
references.citation: Clin Cancer Res. 2003 Jul;9(7):2673-7
references.pmid: 12855646
references.citation: Semin Hematol. 2005 Jul;42(3 Suppl 2):S9-16
references.pmid: 16015507