膀胱癌细胞中DAPK基因启动子甲基化状态分析

The methylation status analysis of DAPK promoter in bladder cancer cell fines

目的分析DAPK抑癌基因在T24、5637、ScaBER三种膀胱癌细胞中的表达情况及该基因启动子区的甲基化状态。方法采用半定量RT-PCR和Western blot分别检测三种膀胱癌细胞中DAPK基因的表达,用甲基化特异PCR(MSP)方法检测三种细胞中的DAPK基因启动子甲基化状态。观察甲基转移酶(DMNT)抑制剂5-aza-2'-deoxy-eytidine(5-aza-CdR)对以细胞中的基因表达和甲基化状态的影响。结果T24细胞中未检测到DAPK基因的表达,也未检测到启动子甲基化;5637细胞中该基因表达水平极低,在SeaBER细胞中该基因的表达较前两者要高。5637细胞和ScaBER细胞中均有甲基化改变。2.5μmol/l浓度的5-aza-CdR可以有效上调5637和SeaBER细胞的DAPK基因的表达。结论抑癌基因DAPK的表达异常与移行细胞癌的发生发展有重要联系,且基因启动子区CpG岛的异常甲基化在调节DAPK基因的表达中发挥重要作用。

Objective To investigate the expression of death-associated protein kinase （DAPK） in bladder cancer cell lines and detect the aberrant methylation status in its promoter. Methods Semiquantitative RT-PCR and Western blotting were performed to detect the expression of DAPK in bladder cancer cell lines （T24,5637 ,ScaBER）. Bisulfite modification and methylation specific PCR were carried out to detect the methylation status. The bladder cancer cells were treated with DNA methyltransferase inhibitor 5-aza-2＇-deoxycytidine （2.5 i.Lmol/L） for 72 h,then DAPK expression and methylation were detected. Results DAPK was not detected in T24 cells either at mRNA level or protein level, and low expression of DAPK existed in 5637 and SeaBER cells. Its expression could be up-regulated by in vitro treatment with the inhibitor 5-aza-2＇ -deoxycytidine （2.5μmol/L） for 72 h. Aberrant methylation of DAPK was detected in 5637 and ScaBER ceils. Conclusion DAPK expression is frequently down-regulated in transi- tional cell carcinoma, and hypermetylation of the promoter may be one of the most important mechanisms involved.