Let-7a对人乳腺癌细胞生长的抑制作用及机制  

The inhibitory effect and mechanesm of Let-7a on human breast cancer cell in vitro

作　　者：吴凯[1] 吴爱国 马雷[1] 杨华峰[1] 邵国利[1] 

机构地区：[1]南方医科大学珠江医院普通外科,广东广州510282

出　　处：《中国普通外科杂志》2010年第5期506-510,共5页China Journal of General Surgery

基　　金：广东省科技计划基金资助项目(2008B030301345)

摘　　要：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 cells in vitro and its possible mechanism.Methods Human breast cancer MCF-7 cells were transfected with let-7a（experimental group） and siRNA（siRNA group） and lipofectamine（control group） by using lipofectamineTM2000.The cell transfection efficiency was observed by fluorescence microscope,cell proliferation inhibitory rate was measured using CCK-8 assay,mRNA expression of IMP-1 of each group was detected using semi-quantitive reverse transcription-polymerase chain reaction（RT-PCR）,and the level of IMP-1 protein expressions was measured by Western blot 48 hours after transfection.Results The cell transfection was efficiency and no significant difference between the let-7a group and siRNA group.Let-7a inhibited the proliferation of MCF-7 cells in a dose-and time-dependent manner（both P〈0.05）.Apoptotic index in let-7a group was obviously higher than that in the siRNAgroup and control groups（both P〈0.05）.The expression of IMP-1mRNA in let-7a group was significantly lower than those in the siRNA group and control group（P〈0.01）.Expression of IMP-1 protein in MCF-7 cells was confirmed and it was clear that the specific band in let-7a group was obviously weaker than that in siRNA group and control groups.Conclusions let-7a can inhibit the proliferation of MCF-7 cells by reducing the IMP-1 gene expression in vitro.

关 键 词：乳腺肿瘤 IMP-1基因 let-7a 微小RNA 细胞转染 

分 类 号：R737.9[医药卫生—肿瘤]