ABSTRACT
Objective: To investigate the effect of 5-Aza-dC (5-aza-2'-deoxycytidine) on cell cycle of multidrug resistant cells and its mechanism. Methods: Inhibitory effects of 5-Aza-dC on proliferation of breast cancer MCF-7/ADR cells and oral epidermoid carcinoma KBV/200 cells were detected by MTT method. The changes of cell cycle distribution were examined by flow cytometry when the cells were treated with 5-Aza-dC at different concentrations for 72 h or treated with the same concentration of 5-Aza-dC (10 μmol/L) for different time. The expression levels of cyclin A, cyclin E and p21waf1/cip1 mRNAs and proteins were detected by real-time fluorogenic quantitative-PCR and Western blotting, respectively. Results: The proliferation of MCF-7/ADR and KBV/200 cells was suppressed significantly after 5-AzadC treatment. The cell cycle was arrested at G2/M phase in dose- and time-dependent manners. The expression levels of cyclin A, cyclin E and p21waf1/cip1 mRNAs and proteins were elevated. Conclusion: The cell cycle of MCF-7/ADR and KBV/200 cells can be arrested at G2/M phase which consequently results in the inhibition of proliferation of multidrug resistant cells induced by 5-Aza-dC. The molecular mechanisms may be related with up-regulation of expressions of cyclin A, cyclin E and p21waf1/cip1 mRNAs and proteins. Copyright © 2012 by TUMOR.