MicroRNA-100对肝癌细胞增殖活力和细胞周期的影响

 目的：探讨microRNA-100(miR-100) 对肝癌细胞增殖活力和细胞周期的影响及其可能机制。方法：通过脂质体介导将人工合成的miR-100模拟物及其阴性对照转染人肝癌HepG2细胞，用细胞计数试剂盒8(CCK-8)方法检测转染后HepG2细胞的增殖活力，用流式细胞术判定细胞周期分布，并进一步用实时荧光定量RT-PCR和Western blotting分析Polo样激酶1(Plk1)的表达水平。结果：荧光显微镜下观察到经阳离子脂质体介导的细胞转染效率大于85%。转染miR-100模拟物的实验组细胞的增殖抑制率在24、48和72 h分别为(43.5±12.2)%、(46.5±3.7)%和(52.1±0.2)%，均显著高于对照组细胞（P<0.01），并且在72 h实验组细胞增殖指数（35.8±1.4）低于阴性对照组（39.2±1.0）和单纯脂质体组（40.7±2.0）(P<0.05)。同时与对照组相比，实验组细胞Plk1　mRNA和蛋白表达水平在转染miR-100后 72 h明显降低（P<0.05)。结论：miR-100可抑制肝癌细胞增殖，其机制可能与其下调Plk1的表达有关。

Effect of microRNA-100 on proliferation activity and cell cycle of hepatocarcinoma cells

AIM：To investigate the effect of microRNA-100 (miR-100) on the proliferation activity and cell cycle of hepatocarcinoma cells. METHODS：Synthetic miR-100 mimic and its negative control were transfected into human hepatocarcinoma HepG2 cells by liposome method. After transfection, the cell counting kit-8 (CCK-8) was used to measure the cell proliferation activity. The cell cycle distribution was determined by flow cytometry. The expression of Polo-like kinase 1 (Plk1) at mRNA and protein levels was detected by quantitative real-time PCR (qRT-PCR) and Western blotting. RESULTS：The transfection efficiency mediated by cationic liposome was greater than 85%. The inhibitory rates of cell proliferation in HepG2 cells were (43.5±12.2)%, (46.5±3.7)% and (52.1±0.2)% at 24 h, 48 h and 72 h after transfected with miR-100 mimic, respectively, which were significantly increased as compared with the control cells. Moreover, the cell proliferation index in experimental group (35.8 ± 1.4) was higher than that in negative control group (39.2 ± 1.0) and simple liposome group (40.7 ± 2.0) at 72 h. At the same time, the mRNA and protein expression levels of Plk1 obviously decreased in HepG2 cells transfected with miR-100 at 72 h after transfection. CONCLUSION：miR-100 suppresses the proliferation activity of hepatocarcinoma cells by down-regulating Plk1 gene expression.