目的：研究雷公藤内酯醇（triptolide，TP）对人肝癌SMMC-7721细胞增殖的影响以及对P53基因的去甲基化作用。方法：MTT法检测TP对SMMC-7721细胞增殖的影响，甲基特异性PCR检测TP对SMMC-7721细胞P53 基因甲基化的影响，RT-PCR检测SMMC-7721细胞甲基转移酶DNMT1、DNMT3a、DNMT3b mRNA的表达，Western blotting检测SMMC-7721细胞中P53蛋白的表达。结果：TP剂量依赖性抑制SMMC-7721细胞的增殖（P<0.05），40 ng/ml时的抑制率达（73.5±3.02）%，其半数抑制浓度（IC50）约为20 ng/ml。TP显著抑制SMMC-7721细胞中DNMT1、DNMT3a、DNMT3b mRNA的表达（P<0.05, P<0.01）；TP作用后P53 基因的高甲基化被逆转，并呈剂量依赖性；TP可显著增强SMMC-7721细胞中P53蛋白的表达。结论：TP可通过抑制甲基转移酶使P53基因去甲基化，促进P53蛋白的表达，从而抑制SMMC-7721细胞的增殖。

Objective: To study the effect of triptolide (TP) on the proliferation of hepatocarcinoma SMMC-7721 cells and its effect on demethylation of P53 gene. Methods: The effect of TP on proliferation of SMMC-7721 cells was measured by MTT method, the effect of TP on P53 gene methylation in SMMC-7721 cells was analyzed by methylation specific PCR, the expressions of methyltransferase DNMT1, DNMT3a and DNMT3b mRNA in SMMC-7721 cells were measured by RT-PCR, and the protein expression of P53 in SMMC-7721 cells was detected by Western blotting assay. Results: TP inhibited the proliferation of SMMC-7721 cells in a dose-dependent manner (P<0.05), with the inhibitory rate being (73.5±3.02)% at 40 ng/ml TP, and IC50 of TP was 20 ng/ml. TP significantly inhibited DNMT1, DNMT3a, and DNMT3b mRNA expressions in SMMC-7721 cells (P<0.05, P<0.01), and dose-dependently reversed the hypermethylation of P53 gene and enhanced P53 protein expression in SMMC-7721 cells. Conclusion: TP can inhibit the proliferation of SMMC-7721 cells through the inhibiting methyltransferase expression, which augment the demethylation of P53 gene and results in the increased expression of P53 protein.

国家自然科学基金资助项目（No. 81072444）