5-脱氧杂氮胞苷对HepG2肝癌细胞恶性表型及caspase-3和bcl-2表达的影响

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

目的 观察5-脱氧杂氮胞苷(5-aza-CdR)对HepG2细胞株生长抑制和凋亡的影响。方法 采用四甲基偶氮唑盐 (MTT)法检测5-aza-CdR对HepG2细胞的生长抑制;通过Giemsa染色观察细胞贴壁克隆形成率;用流式细胞术分析5-aza-CdR对细胞凋亡的影响;用免疫细胞化学方法检测caspase-3和bcl-2蛋白的表达变化。结果 5-aza-CdR可抑制HepG2细胞 株生长,并呈剂量依赖性,第4天时的抑制率最大,可达60.2%,细胞贴壁克隆形成率从36.3%下将至17.3%;流式细胞术结 果表明8μmol/L5-aza-CdR作用第4天凋亡率为10.26%,与对照相比差异有统计学意义;caspase-3蛋白表达明显增加,而 bcl 2蛋白表达则明显下调。结论 5-aza-CdR可抑制HepG2细胞增殖并能促进凋亡,其机制可能是通过恢复某些抑癌基因表 达,上调caspase-3蛋白并下调bcl-2蛋白表达。

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.