MiR-526b suppresses cell proliferation, cell invasion and epithelial-mesenchymal transition in breast cancer by targeting Twist1

OBJECTIVE: The aberrant expression of microRNAs (miRNAs) acts as crucial regulators in the tumorigenesis of breast cancer (BC). The aim of the study is to investigate the functional effects of miR-526b expression in breast cancer progression. PATIENTS AND METHODS: The expression level of miR-526b in breast cancer tissues and cell lines was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Cell proliferation, migration, and invasion capacity was detected by CCK-8 cell proliferation, colony formation, and transwell invasion assays after up-regulating or down-regulating miR-526b expression in breast cancer cells. Bioinformatics analysis and Dual-Luciferase reporter gene assays were used to demonstrate that Twist1 was a target of miR-526b. Western blot analysis was also performed. RESULTS: We showed that miR-526b expression was significantly downregulated in breast cancer tissues compared to adjacent normal tissues. Lower miR-526b expression was associated with lymph node metastasis in breast cancer patients. Function assays showed that upregulation of miR-526b expression suppressed cell proliferation, cell colony formation, and cell invasion ability in breast cancer. Furthermore, the upregulation of miR-526b suppressed EMT makers Vimentin expression but increased the E-cadherin expression. Mechanically, we showed that miR-526b inhibited cell EMT process by targeting Twist1 expression. CONCLUSIONS: Thus, our evidence indicated that miR-526b may serve as a potential target of breast cancer treatment.