Objective To investigate the inhibition of leech extract on expression of DNA methyltransfer (DNMTs) genes of HepG2 cells. Methods The inhibition and proliferation of leech extract for HepG2 cells were determinated with MTT methods. The IC50 concentration was calculated with the regression equation. The 1/2 madicated volume of IC50 was used to treat the HepG2 cells and the 5-Aza-cdR to do as a positive control, and then, the DNMT1, DNMT3a, DNMT3b mRNA and protein expressions of HepG2 cells were detected with RT-PCR and im-munohistochemistry methods after 72 h. Results The HepG2 cells were in higher expression, and DNMT1, DNMT3a and DNMT3b in middle or low expression. After treated by leech ex-trct, compared with that in control group, the expression levels of DNMT1 and DNMT3a were significantly lowered, and DNMT3b was not in expression (P <0.01); compared with the 5 -Aza-cdR group, DNMT1 in leech extract group was less than that in 5-Aza-cdR group, but DN-MT3a and DNMT3b were lowwered significantly than that in 5-Aza-cdR group (P<0.05). Conclusion Leech extract can inhibit the expressions of DNMTs in HepG2 cells. And the role of one may be the anti-tumor mechanisms of leech.%目的 探讨水蛭提取物对肝癌HepG2细胞DNA甲基转移酶(DNMTs)表达的抑制作用.方法 采用MTT法检测水蛭提取物对肝癌HepG2细胞的增殖抑制作用,根据回归方程计算出半教抑制浓度(IG50).以1/2 IC50含药量的水蛭提取物处理肝癌HepG2细胞,并以5-脱氧杂氮胞苷(5-Aza-cdR)处理作阳性对照,处理72 h时采用逆转录-聚合酶链反应(RT-PCR)、免疫组化等方法检测肝癌HepG2细胞DNMT1、DNMT3a、DNMTI3b mRNA及蛋白表达水平.结果 肝癌HepG2细胞DNMT1呈高表达,DNMT3a、DN MT3b呈中低度表达.经水蛭提取物处理后肝癌HepG2细胞DNMT1、DNMT3a表达水平明显下降,DNMT3b基本不表达,与空白对照组比较差异有统计学意义(P＜0.01),与5-Aza-cdR组比较,水蛭提取物组降低DNMT1作用弱于5-Aza-cdR,降低DNMT3a、DNMT3b作用明显优于5-Aza-cdR组(P＜0.05).结论 水蛭提取物能抑制肝癌HepG2细胞DNTMs表达,参与DNA去甲基化作用可能是水蛭抗肿瘤的机制之一.
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