miR-124和miR-520b下调Eps8表达并抑制HeLa细胞增殖

MicroRNA-124 and microRNA-520b Inhibit Proliferation through Downregulating Eps8 in HeLa Cells

Eps8是一个多功能的信号分子,参与肌动蛋白重排、受体内吞和肿瘤的发生发展.为了寻找靶向Eps8的microRNAs(miRNAs)并研究其在宫颈癌中的调控作用,本文采用软件预测获得4个可能调控Eps8表达的miRNAs.利用双荧光素酶报告系统和Western印迹研究发现,miR-124和miR-520b结合到人EPS8 mRNA的3'非翻译区(untranslated region,UTR)并有效抑制Eps8蛋白的表达.进一步细胞存活检测、MTT法和克隆形成实验分析显示,miR-124和miR-520b过表达显著抑制HeLa细胞的生长和增殖.而且,miRNA调节的Eps8下调能提高HeLa细胞对化疗药物顺铂的敏感性.同时证明,miR-124和miR-520b激活肿瘤抑制基因p53与下游基因p21报告基因转录活性,也相应地上调了p53与p21的蛋白表达.这些结果提示,miR-124和miR-520b下调癌基因EPS8表达,从而抑制HeLa细胞增殖,负调控宫颈癌细胞生长.

Eps8 is a multifunctional signal molecule involved in actin remodeling, receptor endocytosis and tumorigenesis. To find microRNAs （miRNAs） targeted EPS8 and investigate their regulation in cervical cancer, four miRNAs were predicted to regulate the expression of Eps8. The dual luciferase reporter system and Western blotting showed that miR-124 and miR-520b could bind to the 3＇ untranslated region （UTR） of human EPS8 mRNAs and efficiently inhibit the expression of EpsS. Furthermore, cell survival, MTT analysis and colony formation assays revealed that the overexpression of miR-124 and miR-520b suppressed growth and proliferation in HeLa cells. Moreover, miR-124 and miR- 520b sensitized HeLa ceils to the cytotoxicity of chemotherapy drug, cisplatin. In addition, experiment results showed that miR-124 and miR-520b activated the transcriptional activities of reporter genes for tumor suppressor p53 and downstream gene p21, and accordingly upregulated their protein levels. Thesefindings suggest that miR-124 and miR-520b downregulate the expression of Eps8 and inhibit proliferation in HeLa cells, and negatively regulate cellular growth in cervical cancer.