天花粉蛋白对宫颈癌HeLa细胞TSLC1基因甲基化及其表达的影响

目的：检测人宫颈癌HeLa细胞中TSLC1基因甲基化的状况，研究在人宫颈癌HeLa细胞凋亡过程中TSLC1基因甲基化的变化情况，探讨肿瘤细胞凋亡与抑癌基因甲基化的相关性，并进一步证实天花粉蛋白（TCS）去甲基化作用是否存在普遍性，以促进天花粉蛋白的临床应用。方法：应用甲基化特异性PCR（MSP）法检测人宫颈癌HeLa细胞及其凋亡过程中TSLC1基因甲基化的状况；采用实时定量RT-PCR技术检测TCS处理前、后HeLa细胞TSLC1基因表达的变化。结果：肿瘤抑制基因TSLC1在人宫颈癌HeLa细胞中呈高度甲基化状态，经40μg／mL TCS处理48h后，TSLC1基因甲基化程度明显降低；RT-PCR检测结果显示，TCS处理组HeLa细胞中TSLC1 mRNA的表达量高于未处理组，提示TSLC1基因启动子区CpG岛甲基化是导致其低表达的重要机制。结论：肿瘤抑制基因TSLC1启动子甲基化在人宫颈癌癌变过程中可能是一种重要的分子调控机制；人宫颈癌HeLa细胞凋亡与抑癌基因的去甲基化之间可能存在某些密切的相关性；TCS对肿瘤抑制基因TSLC1有一定的去甲基化作用。

The Effect of the Trichosanthin on the Methylation and Expression of TSLC1 Gene in Cervical Carcinoma HeLa Cells

Objective： To study TSLCl gene methylation status in HeLa cells and their apoptotic process, and to discuss the relationship between the apoptosis and tumor suppressor gene methylation, and further to confirm the universal demethylation role of trichosanthin（TCS）. Methods： The methylation-specific PCR（MSP） was used to detect the TSLCl gene methylation status; the real-time quantitative RT-PCR technique was used to detect the TSLCl gene expression changes treated by TCS. Results： The TSLCl gene showed high methylation status in HeLa cells, but it was significantly lower which were treated by TCS（40μg/mL, 48 h）. RT-PCR results showed that the TSLCl mRNA expression level was higher than the untreated group. It＇s suggested that the CpG island methylation of TSLCl gene promoter was an important mechanism leading to low expression. Conclusion： The promoter methylation of tumor suppressor gene TSLCl may be an important molecular mechanism in human cervical cancer process. The apoptosis of HeLa cells would be related closely to the methylation of tumor suppressor genes. The TCS showed demethylation on the TSLCl gene.