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目的探讨let-7a对人乳腺癌MCF-7细胞株的抑制作用及机制。方法分别用lipofectami-neTM2000介导的let-7a转染MCF-7细胞株(实验组)和siRNA转染细胞株(阴性对照组),并设空白对照组(脂质体转染组)。使用荧光显微镜观察细胞转染效率;CCK-8法检测细胞增殖抑制率;半定量RT-PCR法检测IMP-1 mRNA的表达;Western blot法测定转染48 h后IMP-1蛋白的表达水平。结果实验组和阴性对照组的细胞转染效率无明显差别;let-7a组细胞增殖抑制率明显高于阴性对照组及空白对照组(均为P<0.05),且具有时间和浓度依赖性;let-7a组的IMP-1 mRNA表达水平明显低于空白对照组和阴性对照组(F=220.384,P=0.000);在MCF-7细胞中存在IMP-1蛋白表达,let-7a转染组特异性条带明显弱于两个对照组。结论 let-7a对人乳腺癌MCF-7细胞增殖有抑制作用,其机制可能与抑制IMP-1的基因表达有关。
Objective To investigate the inhibitory effect of let-7a on human breast cancer cell line MCF-7 and its mechanism. Methods MCF-7 cells (experimental group) and siRNA transfected cells (negative control group) were transfected with lipofectami-neTM2000-mediated let-7a and blank control group (lipofectamine group). The cell transfection efficiency was observed by fluorescence microscopy. The cell proliferation inhibition rate was determined by CCK-8 assay. The expression of IMP-1 mRNA was detected by semi-quantitative RT-PCR. The expression of IMP-1 protein was detected by Western blot 48 h after transfection. Results There was no significant difference in cell transfection efficiency between the experimental group and the negative control group. The proliferation inhibition rate of let-7a group was significantly higher than that of the negative control group and the blank control group (both P <0.05) The expression of IMP-1 mRNA in let-7a group was significantly lower than that in blank control group and negative control group (F = 220.384, P = 0.000). The expression of IMP-1 protein in MCF-7 cells and the let- Specific bands were significantly weaker than the two control groups. Conclusion let-7a inhibits the proliferation of human breast cancer MCF-7 cells, and its mechanism may be related to the inhibition of IMP-1 gene expression.