miR-21通过靶向PDCD4调控三阴性乳腺癌细胞的迁移和侵袭

目的： 研究miR-21在三阴性乳腺癌细胞MDA-MB-231中的表达，以及其是否通过调控PDCD4影响MDA-MB-231细胞的迁移和侵袭。方法： 采用实时定量PCR（qPCR）法检测MDA-MB-231细胞和正常乳腺细胞MCF-10A中miR-21和PDCD4 mRNA的表达。将MDA-MB-231细胞随机分为5组：空白对照组，转染miR-21模拟物组，模拟物对照组，转染miR-21抑制物组和抑制物对照组。采用Western blot法检测MDA-MB-231细胞PDCD4蛋白的表达；采用荧光素酶报告基因试剂盒检测转染不同载体后荧光强度的变化来判断miR-21的靶标；采用Transwell实验检测各组细胞的迁移和侵袭数目。结果： miR-21和PDCD4 mRNA在MDAMB-231细胞中的表达水平分别明显高于和低于MCF-10A细胞（P均 < 0.01）。过表达或抑制miR-21可调节PDCD4的表达水平。荧光素酶报告基因试剂盒检测结果显示miR-21可直接靶向调控PDCD4的表达。Transwell实验结果表明过表达miR-21表达能增强MDA-MB-231细胞的迁移和侵袭能力。结论： 在MDA-MB-231细胞中，miR-21通过靶向调控PDCD4表达影响细胞的迁移和侵袭。miR-21可能成为抑制三阴性乳腺癌迁移和侵袭的靶点。

Regulation of migration and invasion of triple-negative breast cancer cell MDA-MB-231 by miR-21 via targeting PDCD4

OBJECTIVE: To explore the roles of miR-21 in regulating migration and invasion of triplenegative breast cancer MDA-MB-231 cells via targeting PDCD4. METHODS: Quantitative real-time PCR (qPCR) was used to detect the expression of miR-21 and PDCD4 mRNA in MDA-MB-231 and MCF-10A cells. MDA-MB-231 cells were divided into five groups,including blank control,miR-21 mimics,miR-21 inhibitor, negative mimics and negative inhibitor. Western blotting was used to detect PDCD4 protein expression, and luciferase reporter gene assay was used to detect whether miR-21 was targeting PDCD4. Migration and invasion of MDA-MB-231 cells were detected using Transwell chambers. RESULTS: miR-21 and PDCD4 mRNA in MDA-MB-231 cells was significantly higher and lower than that of MCF-10A cells, respectively (P < 0.01). The overexpression or inhibition of miR-21 were concurrent with the up-or downregulation of PDCD4 expression. Luciferase reporter gene assays showed that PDCD4 was a direct target of miR-21. Transwell assays demonstrated that modulating miR-21 with mimics or inhibitors changed the migration and invasion of MDA-MB-231 cells. CONCLUSION: Migration and invasion of MDA-MB-231 cells were regulated by miR-21 through targeting PDCD4. Regulating the expression of miR-21 could be a novel target for inhibiting these invasive activities in triple-negative breast cancers.