MicroRNA-940在乳腺癌中的表达变化及作用机制

Expression and mechanism of microRNA-940 in breast cancer

目的探讨microRNA-940(miR-940)在乳腺癌组织和细胞中的表达以及对乳腺癌细胞增殖、侵袭、迁移能力的影响及其相关分子机制。方法实时定量聚合酶链反应(Real-time PCR)检测2016年1月~2017年1月我院手术切除的78例患者的乳腺癌组织、癌旁组织和人乳腺癌细胞系MCF-7、SK-BR-3、MDA-MB-231、BT-549及人正常乳腺细胞系MCF-10 A中miR-940的表达情况。在乳腺癌细胞系MDA-MB-231中利用脂质体LipofectaminsTM2000转染miR-940模拟物上调miR-940的表达,CCK-8实验检测细胞增殖活性的改变,小室侵袭及迁移实验(transwell)检测细胞侵袭、迁移能力的改变。生物学信息法预测miR-940的可能作用靶基因,双荧光素酶报告实验检测miR-940与CXC趋化因子受体2 (CXCR2)的3'UTR区结合情况,Western blotting检测miR-940对CXCR2蛋白表达的影响。结果 miR-940在乳腺癌组织和细胞中表达明显降低(P<0.01),并且miR-940的表达与TNM分期和淋巴结转移密切相关(P<0.01)。上调MDA-MB-231细胞miR-940表达后,细胞的增殖活性明显下降(P<0.01),侵袭及迁移能力明显下降(P<0.01)。双荧光素酶报告显示,miR-940可与CXCR2的3'UTR区特定序列结合显著抑制荧光素酶活性(P<0.01),上调miR-940后细胞中CXCR2蛋白的表达均明显下降(P<0.01)。结论miR-940在乳腺癌中的表达降低,miR-940可以通过靶向CXCR2抑制乳腺癌细胞的增殖、侵袭及迁移能力。

Objective To explore microRNA-940(miR-940) expression in breast cancer tissues and cells,as well as its effect on breast cancer cell proliferation,invasion and migration capacities and the related molecular mechanism.Methods miR-940 expression in breast cancer tissues,para-carcinoma tissues from 78 patients undergoing surgical resection in our hospital from January 2016 to January 2017,and human breast cancer cell lines MCF-7,SK-BR-3,MDAMB-231 and BT-549,as well as that in normal human breast cell line MCF-10 A,were detected using Real-time PCR.miR-940 expression in breast cancer cell line MDA-MB-231 was up-regulated through transfection with miR-940 mimics using liposome LipofectaminsTM2000.Changes in cell proliferation capacity were detected using CCK-8 assay,while those in cell invasion and migration capacities were detected using transwell assay.The potential target gene of miR-940 was predicted by biologic information method,binding of miR-940 with the 3’UTR of CXC chemokine receptor 2(CXCR2) was detected using dual luciferase reporter assay,and the effect of miR-940 on CXCR2 protein expression was detected using Western blotting.Results miR-940 expression in breast cancer tissues and cells was remarkably down-regulated(P < 0.01),and miR-940 expression was closely correlated with TNM stage and lymph node metastasis(P<0.01).Up-regulating miR-940 expression in MDA-MB-231 cells would lead to markedly decreased cell proliferation capacity(P < 0.01),as well as notably lowered cell invasion and migration capacities(P< 0.01).Dual luciferase reporter assay indicated that miR-940 might bind with specific sequences in the 3’UTR of CXCR2,thus evidently suppressing luciferase activity(P < 0.01);meanwhile,up-regulating miR-940 would result in apparently reduced CXCR2 protein expression in cells(P < 0.01).Conclusion miR-940 expression is down-regulated in breast cancer,which can target CXCR2 to suppress breast cancer cell proliferation,invasion and migration.