Effects of microRNA-195-5p on growth, migration and invasion of breast cancer cells / 肿瘤

ABSTRACT

Objective: To investigate the effects of up- or down-regulated microRNA (miRNA, miR)-195-5p on the growth, migration and invasion of human triple negative breast cancer MDAMB-231 and BT-549 cells, and to explore the potential mechanism. Methods: The Cancer Genome Atlas (TCGA) database was used to analyze the expression level of miR-195-5p in breast cancer. MiR-195-5p-mimics was transfected into MDA-MB-231 cells to construct the recombinant cells with exogenous miR-195-5p overexpression. MiR-195-5p-inhibitor was transfected into BT-549 cells to construct the recombinant cells with endogenous miR-195-5p gene silence. The expression level of miR-195-5p in the recombinant cells was detected by realtime fluorescent quantitative PCR. The proliferation of MDA-MB-231 and BT-549 cells was detected by MTT assay, the longitudinal migration and invasion abilities were detected by Transwell migration and invasion assays, the lateral migration ability was evaluated by wound healing assay. The mRNA expression levels of migration-associated factor yes-associated protein-1 (YAP-1), and epithelialmesenchymal transition (EMT) markers (including E-cadherin, snail and vimentin) were detected by real-time fluorescent quantitative PCR. Meantime, the expression levels of EMT markers [including zinc finger E-box binding homeobox 1 (ZEB1), E-cadherin, N-cadherin and vimentin), YAP-1, and phosphorylated YAP-1 (p-YAP-1) were detected by Western blotting. Results: The expression of miR-195-5p in breast cancer tissues was low. The expression of miR-195-5p in MDA-MB-231 cells was lower than that in BT-549 cells (P < 0.001). After the transfection of miR-195-5p-mimics into MDA-MB-231 cells, the expression of miR-195-5p was significantly increased (P < 0.001); while the expression of miR-195-5p in BT-549 cells transfected with miR-195-5p-inhibitor was decreased (P < 0.001). After the over-expression of miR-195-5p, the proliferation, migration and invasion abilities of MDA-MB-231 cells were decreased (all P < 0.05); but the opposite phenomenon was observed in BT-549 cells with down-regulation of miR-195-5p (all P < 0.05). The expression level of E-cadherin mRNA increased, but the expression levels of YAP-1, vimentin and snail mRNAs decreased in MDA-MB-231 cells transfected with miR-195-5p-mimics (all P < 0.05). The expression level of E-cadherin protein increased (P < 0.001), but the expression levels of ZEB1 (P < 0.05), N-cadherin (P < 0.01) and vimentin proteins (P < 0.05) decreased in MDAMB-231 cells with miR-195-5p overexpression, suggesting that the EMT process might be inhibited. The expression levels of migration-related markers YAP-1 and p-YAP-1 proteins in MDA-MB-231 cells with miR-195-5p overexpression were significantly down-regulated (P < 0.05 and P < 0.01). Conclusion: The expression of miR-195-5p is down-regulated in breast cancer, and can inhibit the proliferation, migration, invasion and EMT of breast cancer cells, which may be related to reducing the activity of Hippo/YAP signaling pathway.