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

Abstract

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. 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. 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. Thus, our evidence indicated that miR-526b may serve as a potential target of breast cancer treatment.