三氯乙烯致肝细胞毒性中SET启动子区甲基化水平的改变

Trichloroethylene-induced abnormal methylation on promoter region of SET in hepatic L-02 cells

目的研究三氯乙烯（Trichlorethylene，TCE）致肝细胞毒性中SET基因启动子区甲基化水平的改变。方法培养L—02肝细胞，使用0、1、2、4、8mmol／L浓度的TCE处理24h，提取细胞基因组DNA，进行亚硫酸氢盐修饰，用PCR扩增目标序列，重亚硫酸氢盐测序法（t3sP）分析TCE作用下肝细胞中SET基因启动子区甲基化状态。结果与对照组比较，TCE处理后L-02肝细胞中SET基因启动子区甲基化水平下降，且随着TCE染毒浓度的增加，SET基因启动子区甲基化水平递减。对SET启动子区甲基化差异位点进行分析发现，差异有统计学意义的甲基化位点有73个，已知转录因子结合位点9个。结论TCE致L-02肝细胞毒性中SET基因启动子区甲基化水平下降，影响转录因子的结合，继而使SET蛋白表达升高。

Objective To explore the trichloroethylene-induced alteration of methylation on the promoter region of SET and related mechanisms in hepatic L-02 cells. Methods L-02 cells were treated with different concentrations ofTCE（0 mmol/L, 1 mmol/L, 2 mmol/L, 4 mmol/L, 8 mmol/L） for 24 h. The genomic DNA were then extracted and modified by bisulfite sodium. The DNA methylation was then analyzed using bisulfite sequencing PCR （BSP）. Results The overall methylation on promoter region of SET was decreased along with the increased concentrations of TCE in hepatic L-02 cells. Moreover, 73 CpG islands were found abnormally altered, among which 9 were predicted in transcriptional factor binding regions. Conclusion The decreased levels of CpG islands in the transcriptional factor binding region may contribute to the elevation of SET in TCE-induced hepatotoxicity.