5-aza-CdR对肝癌SMMC7721细胞株PDCD4基因甲基化及表达的影响

目的 研究5-氮杂-2'-脱氧胞苷(5-aza-CdR)在肝癌细胞株SMMC7721中对程序性细胞死亡因子4(PDCD4)表达的影响及可能机制.方法 培养肝癌细胞株SMMC7721,用5-aza-CdR处理肝癌细胞株SMMC7721,Western-blotting检测DNMT3b、PDCD4蛋白在处理前后的变化,甲基化特异性PCR即MSP检测PDCD4基因启动子区域甲基化水平.结果 1×10~(-6)mol/L、5×10~(-6)mol/L的5-aza-CdR作用于SMMC7721细胞后,DNMT3b表达水平降低,而PDCD4表达水平升高,且浓度之间有差异;MSP示药物处理前PDCD4启动子区域处于高甲基化水平,在用5×10~(-6)mol/L药物处理后,其启动子发生了去甲基化.结论 5-aza-CdR可以抑制DNMT3b在SMMC7721中的表达,且可能通过改变抑癌基因PDCD4启动子甲基化状态影响PDCD4表达.

Effects of 5-aza-CdR on methylation and expression of PDCD4 gene in hepatocellular carcinoma cell line SMMC7721

Objective To investigate the effects of 5-aza-CdR on expression of programmed cell death factor 4 (PDCD4) in SMMC7721and explore its possible mechanism. Methods Hepatocellular carcinoma cell line SMMC7721 was cultivated with 5-aza-CdR inhibiting the expression of DNMT3b. Western blotting was used to determine the changes of DNMT3b and PDCD4 proteins and the methylation level of PDCD4's promoter was tested by methylation specific polymerase chain reaction(MSP). Results Using the 5-aza-CdR on concentration of 1×10-6mol/L and 5×10-6mol/L to cultivate SMMC7721, the expression of DNMT3b protein was decreased while the PDCD4 protein was increased. The methylation level of PDCD4's promoter was high in SMMC7721. However, after the treatment of 5-aza-CdR on concentration of 5×10-6mol/L, the promoter of PDCD4 had demethylation. Conclusion The expression of DNMT3b can be inhibited by 5-aza-CdR and DNMT3b may control the expression of PDCD4 in SMMC7721 by influencing the methylation status of its promoter.