miR-204通过下调Bcl-2和Sirt1表达抑制肝癌细胞生长

Growth inhibition of human hepatocellular carcinoma by miRNA-204 via down-regulation of Bcl-2 and Sirt1 expression

目的探讨微小RNA 204(miR-204)在肝细胞癌中的表达、临床意义及可能分子机制。方法收集手术切除的60例肝细胞癌及对应癌旁肝组织,实时定量PCR(qRT-PCR)检测miR-204在肝癌及癌旁组织中的表达,免疫组织化学染色检测miR-204下游潜在靶点Bcl-2与组蛋白脱乙酰酶1(Sirt1)的表达;用人工合成的miR-204模拟物转染人SMMC-7721肝癌细胞,MTT法及流式细胞术检测SMMC-7721细胞的增殖、凋亡的情况,qRT-PCR、Western blot法分别检测Bcl-2与Sirt1的mRNA和蛋白表达。结果 miR-204在肝癌组织中表达水平显著低于对应癌旁组织;肝癌组织中miR-204低表达与肿瘤大小、肿瘤个数、肿瘤TNM分期显著相关;miR-204低表达组Bcl-2与Sirt1蛋白表达显著高于miR-204高表达组,相关性分析结果显示肝癌组织中miR-204与Bcl-2、Sirt1蛋白表达呈显著负相关;miR-204可显著抑制SMMC-7721细胞的增殖并促进其凋亡,并下调Bcl-2与Sirt1的mRNA与蛋白表达水平。结论 miR-204在肝癌组织中表达下调并与肝癌恶性临床病理特征有关,miR-204抑制肝癌细胞增殖、促进其凋亡的作用可能与下调Bcl-2和Sirt1表达有关。

Objective To investigate the level of microRNA-204 （miR-204） in human hepatocellular carcinoma （HCC） and its effect on the potential mechanism of tumorgenesis. Methods Real-time quantitative PCR （qRT-PCR） was applied to detect the expression of miR-204 in HCC （n = 60） and the corresponding tumor-adjacent normal tissues. The expressions of Bcl-2 and Sirtl were measured by immunohistochemistry （IHC）. The artificial miR-204 was transiently transfected into human SMMC-7721 cells in vitro. The proliferation and apoptosis of the cells were detected by MTF assay and flow cytometry, respectively. The expression levels of Bcl-2 and Sirt1 mRNA and protein were determined by qRT-PCR and Western blotting, respectively. Results The expression level of miR-204 in HCC tissues was significantly lower than that in the adjacent normal tissues, and it was associated with tumor size, number of tumors and advanced TNM stage. The expressions of Bcl-2 and Sirtl in the lower miR-204 level group were both higher than those in the higher miR-204 level group. Correlation analysis showed that miR-204 expression was negatively correlated with Bcl-2 and Sirt1 protein expression levels. Over-expressed miR-204 in SMMC-7721 cells suppressed cell proliferation and promoted cell apoptosis, and down-regulated mRNA and protein expressions of both Bcl-2 and Sirt1. Conclusion The expression of miR-204 in HCC tissues was significantly lower than that in tumor-adjacent normal tissues, miR-204 could inhibit HCC cell proliferation and induce apoptosis by down-regulating the expressions of Bcl-2 and Sirt1.