MicroRNA‐133b suppresses bladder cancer malignancy by targeting TAGLN2‐mediated cell cycle

MicroRNAs (miRNAs), a group of small noncoding RNAs, are widely involved in the regulation of gene expression via binding to complementary sequences at 3′‐untranslated regions (3′‐UTRs) of target messenger RNAs. Recently, downregulation of miR‐133b has been detected in various human malignancies. Here, the potential biological role of miR‐133b in bladder cancer (BC) was investigated. In this study, we found the expression of miR‐133b was markedly downregulated in BC tissues and cell lines (5637 and T24), and was correlated with poor overall survival. Notably, transgelin 2 (TAGLN2) was found to be widely upregulated in BC, and overexpression of TAGLN2 also significantly increased risks of advanced TMN stage. We further identified that upregulation of miR‐133b inhibited glucose uptake, invasion, angiogenesis, colony formation and enhances gemcitabine chemosensitivity in BC cell lines by targeting TAGLN2. Additionally, we showed that miR‐133b promoted the proliferation of BC cells, at least partially through a TAGLN2‐mediated cell cycle pathway. Our results suggest a novel miR‐133b/TAGLN2/cell cycle pathway axis controlling BC progression; a molecular mechanism which may offer a potential therapeutic target. Our results demonstrate that miR‐133b regulate transgelin 2 (TAGLN2) expression and its downstream cell cycle‐signaling proteins by directly targeting the 3′‐untranslated regions of TAGLN2. Our findings support the conclusion that miR‐133b/TAGLN2/cell cycle pathway axis is a factor in BC progression, making this way a potential therapeutic target in BC treatment.