Effect of 5-aza-2′-deoxycytidine on malignant phenotype in HepG2 cells and expression of caspase-3 and bcl-2

Purpose To observe the effect of 5-aza-2′-deoxycytidine on cell growth and apoptosis of HepG2 and the expression of caspase-3 and bcl-2,and to investigate the potential mechanism of its antitumorigenesis. Methods Cell growth inhibition was assayed by MTT method; Colony formation rate was determined by a colony formation experiment in soft agar; Assessment of cell cycle and apoptosis were performed by flow cytometry,and the expression of caspase-3 and bcl-2 were investigated by immunohistochemistry. Results 5-aza-2′-deoxycytidine could inhibit the growth of HepG2 cells in a concentration-dependent manner. 8 μmol/L 5-aza-2′-deoxycytidine could significantly inhibit the cells growth,the inhibitory rate was 60.2% after 96 h. The result of colony formation in soft agar showed that the colony formation rate was significantly dropped from 36.3% to 17.3%,and flow cytometry showed that the rate of apoptosis was 10.26% after treatment by 8 μmol/L 5-aza-2′-deoxycytidine after 96 h. The expression of caspase 3 protein was increased and bcl-2 protein was decreased. Conclusions 5-aza-2′-deoxycytidine can reverse malignant phenotype in HepG2 cells,and the mechanism may be that 5-aza-2′-deoxycytidine restores some tumor suppressor genes expression and increases the expression of caspase 3 while decreased expression of bcl-2.