RESUMO
Objective: To investigate the effect of Homo sapiens (hsa)-microRNA (miRNA, miR)-374c-5p on the sensitivity of human breast cancer MDA-MB-231/DDP cells to cisplatin and its mechanism. Methods: The expressions of hsa-miR-374c-5p and Lim domain kinase 1 (LIMK1) in breast cancer MCF-10A, MDA-MB-231 and MDA-MB-231/DDP cells were detected by real-time fluorescent quantitative PCR. Then the hsa-miR-374c-5p mimics and inhibitor, LIMK1 siRNA and LIMK1 overexpressed plasmid were transfected into cisplatin-resistant human breast cancer MDA-MB-231/DDP cells, respectively. The relative expression levels of hsa-miR374c-5p and LIMK1 mRNA were detected by real-time fluorescent quantitative PCR, the expression level of LIMK1 protein was detected by Western blotting, the cell viability was detected by CCK-8 method, the apoptosis was detected by flow cytometry, and the clone formation ability was tested by plate clone forming assay. Finally, the binding relationship between hsa-miR-374c-5p and LIMK1 was verified by luciferase reporter gene assay. Results: The expression levels of hsa-miR-374c-5p and LIMK1 were reversed in breast cancer MDA-MB-231/DDP cells. The overexpression of hsa-miR-374c-5p or the knockdown of LIMK1 decreased cell viability (both P < 0.05) and clone forming ability (both P < 0.05), increased apoptotic rate (both P < 0.05), and increased the sensitivity of MDA-MB-231/ DDP cells to cisplatin (both P < 0.05); while the effects of hsa-miR-374c-5p knockdown on proliferation, clone formation, apoptosis and cisplatin-sensitivity of MDA-MB-231/DDP cells were reversed (all P < 0.05); and the overexpression of LIMK1 reversed the phenotype changes of MDA-MB-231/DDP cells transfected with hsa-miR-374c-5p mimics (all P < 0.05). Hsa-miR-374c-5p targeted LIMK1 mRNA directly and regulated the expression of LIMK1. Conclusion: Hsa-miR-374c-5p enhances the sensitivity of human breast cancer MDAMB-231/DDP cells to cisplatin by regulating the expression of LIMK1.