miR-139-5p通过调节Notch信号通路对乳腺癌细胞增殖和凋亡的影响

目的:探讨miR-139-5p通过靶向抑制Notch信号通路调控乳腺癌细胞的增殖和凋亡。方法:通过实时定量PCR法检测miR-139-5p以及Notch1在乳腺癌和乳腺上皮细胞中的表达；采用双荧光素酶报告基因法验证miR-139-5p对Notch1的调控作用；通过CCK8和流式细胞术分别检测miR-139-5p与Notch1对乳腺癌细胞MDA-MB-231增殖和凋亡的影响，并通过Western blot法检测miR-139-5p对Notch1及相关凋亡蛋白表达的影响。结果:miR-139-5p在人乳腺癌细胞中表达显著下调（P<0.05），尤其在乳腺癌MDA-MB-231细胞中下调更为显著（P<0.01）；双荧光素酶报告基因实验证实miR-139-5p能与Notch1 3’ UTR结合；同时miR-139-5p过表达能够显著抑制细胞活力，促进细胞凋亡（P<0.01），显著抑制Notch1蛋白表达（P<0.01），进而降低相关凋亡蛋白Bcl-2的表达，增强Bax的表达。 结论:miR-139-5p能够通过抑制靶基因Notch1的表达，抑制乳腺癌细胞的增殖，促进细胞凋亡。

The effect of miR-139-5p on proliferation and apoptosis of breast cancer cells by targeting Notch signal pathway

Objective:To investigate the effect of miR-139-5p on cell proliferation and apoptosis in breast cancer via targeting Notch signal pathway.Methods:The level of miR-139-5p and Notch1 in breast cancer cells and mammary epithelial cells was evaluated by RT-qPCR.Dual luciferase reporter gene assay was applied to analyze the regulation effect of miR-139-5p on 3'UTR of Notch1.Furthermore,CCK8 and flow cytometry assay were used to determine the proliferation and apoptosis of MDA-MB-231 cells,respectively.Finally,the protein expression of Notch1 and its related apoptotic protein were measured by Western blot assay under the regulation of miR-139-5p.Results:Compared with mammary epithelial cells,the level of miR-139-5p in breast cancer cells was significantly decreased(P<0.05),especially in MDA-MB-231 cells(P<0.01).miR-139-5p could bind to specific sequence of Notch13'UTR.Additionally,overexpression of miR-139-5p could significantly attenuate the cell viability and promote the apoptosis of MDA-MB-231 cells(P<0.01).miR-139-5p was capable of inhibiting the protein expression of Notch1 and resulted in decreased expression of Bcl-2 and increased expression of Bax(P<0.01).Conclusion:The mechanism of miR-139-5p on the proliferation and apoptosis of breast cancer cells was mediated by targeting Notch signal pathway.