miR-200b调控PDCD4的表达对乳腺癌细胞增殖和侵袭的影响

目的探讨miR-200b对乳腺癌细胞增殖及侵袭的影响及其可能的分子机制。方法利用荧光实时定量PCR检测人乳腺癌组织及乳腺癌细胞株中miR-200b的表达差异;利用生物信息学方法预测miR-200b的靶基因,并使用免疫蛋白印迹实验对靶基因的表达进行验证;分别将miR-200b siRNA、PDCD4 mimics以及相应对照miRNA转染MCF-7细胞,通过CCK-8实验检测细胞的增殖能力;采用Transwell侵袭实验检测细胞的侵袭能力。结果miR-200b在乳腺癌组织中呈低表达水平,进一步抑制miR-200b的表达,乳腺癌细胞的增殖及侵袭能力显著增强(P<0.05);将miR-200b siRNA、PDCD43′-UTR共转染到乳腺癌MCF-7细胞中,双荧光素酶报告基因结果显示抑制miR-200b的表达后,PDCD4的表达及活性相应上调(P<0.05);同时通过蛋白免疫印迹实验可以发现,抑制miR-200b表达后,PDCD4蛋白表达含量降低,乳腺癌细胞的增殖及侵袭能力明显增强(P<0.05);而过表达PDCD4后PDCD4蛋白表达含量增加(P<0.05),乳腺癌细胞的增殖及侵袭能力明显降低(P<0.05)。结论miR-200b可靶向上调PDCD4基因的表达,从而抑制乳腺癌细胞的增殖及侵袭能力。

Effect of mir-200b regulating the expression of PDCD4 on proliferation and invasion of breast cancer cells

Objective To investigate the effect of miR-200b on the proliferation and invasion of breast cancer cells,and analyze its possible molecular mechanisms.Methods The expressions of miR-200b in human breast cancer tissues and breast cancer cell lines were detected by real-time fluorescent quantitative PCR.The target genes of miR-200b were predicted by bioinformatics methods,and the target gene expression was verified by Western blot.miR-200b siRNA,PDCD4 mimics and corresponding control miRNAs were transfected into MCF-7 cells,then the cell proliferation was detected by CCK-8 assay,cell migration was detected by Transwell invasion assay.Results miR-200b showed low expression in breast cancer tissues,after inhibiting the expression of miR-200b,the proliferation and invasion of breast cancer cells were significantly enhanced(P<0.05);miR-200b siRNA,PDCD43′-UTR co-transfected into breast cancer MCF-7 cells,dual-luciferase reporter gene results showed that the expression and activity of PDCD4 were correspondingly up-regulated after inhibiting the expression of miR-200b(P<0.05).At the same time,Western blot results indicated that after inhibiting the expression of miR-200b,the expression of PDCD4 protein was decreased,the proliferation and invasion of breast cancer cells were significantly increased(P<0.05).Besides,after overexpressing the PDCD4,the expression of PDCD4 protein was increased(P<0.05),and the proliferation and invasion ability of breast cancer cells were significantly reduced(P<0.05).Conclusion miR-200b can inhibit the proliferation and invasion of breast cancer cells by up-regulating the expression of PDCD4 gene.