Long non-coding RNA XIST promotes cell growth and metastasis through regulating miR-139-5p mediated Wnt/β-catenin signaling pathway in bladder cancer

Bladder cancer is one of the most common urological malignancy all over the world. Recently, long non-coding RNA (lncRNA) XIST has been identified as an oncogenic gene in several type of cancers. However, the expression level and functional role of XIST in bladder cancer remain largely unknown. In the present study, we found that XIST was significantly up-regulated in bladder cancer tissues and cell lines, and was correlated with poor prognosis of bladder cancer patients. Furthermore, XIST knockdown significantly inhibited bladder cancer cell growth and metastasis in vitro and tumor growth in vivo. We also demonstrated that XIST acted as a competing endogenous RNA for miR-139-5p and repression of miR-139-5p could restore the inhibitory effects on bladder cancer cells induced by XIST shRNA. In addition, we identified that Wnt1 was a direct target of miR-139-5p, and XIST played the oncogenic role in bladder cancer by activating the Wnt/β-catenin signaling pathway. Taken together, our study suggested that lncRNA XIST may serve as a prognostic biomarker and a potential therapeutic target for bladder cancer.