The lncRNA DLX6-AS1 promoted cell proliferation, invasion, migration and epithelial-to-mesenchymal transition in bladder cancer via modulating Wnt/β-catenin signaling pathway

BACKGROUND: Bladder cancer is the most common human urological malignancies with poor prognosis, and the pathophysiology of bladder cancer involves multi-linkages of regulatory networks in the bladder cancer cells. Recently, the long noncoding RNAs (lncRNAs) have been extensively studied for their role on bladder cancer progression. In this study, we evaluated the expression of DLX6 Antisense RNA 1 (DLX6-AS1) in the cancerous bladder tissues and studied the possible mechanisms of DLX6-AS1 in regulating bladder cancer progression. METHODS: Gene expression was determined by qRT-PCR; protein expression levels were evaluated by western blot assay; in vitro functional assays were used to determine cell proliferation, invasion and migration; nude mice were used to establish the tumor xenograft model. RESULTS: Our results showed the up-regulation of DLX6-AS1 in cancerous bladder cancer tissues and bladder cell lines, and high expression of DLX6-AS1 was correlated with advance TNM stage, lymphatic node metastasis and distant metastasis. The in vitro experimental data showed that DLX6-AS1 overexpression promoted bladder cancer cell growth, proliferation, invasion, migration and epithelial-to-mesenchymal transition (EMT); while DLX6-AS1 inhibition exerted tumor suppressive actions on bladder cancer cells. Further results showed that DLX6-AS1 overexpression increased the activity of Wnt/β-catenin signaling, and the oncogenic role of DLX6-AS1 in bladder cancer cells was abolished by the presence of XAV939. On the other hand, DLX6-AS1 knockdown suppressed the activity of Wnt/β-catenin signaling, and the tumor-suppressive effects of DLX6-AS1 knockdown partially attenuated by lithium chloride and SB-216763 pretreatment. The in vivo tumor growth study showed that DLX6-AS1 knockdown suppressed tumor growth of T24 cells and suppressed EMT and Wnt/β-catenin signaling in the tumor tissues. CONCLUSION: Collectively, the present study for the first time identified the up-regulation of DLX6-AS1 in clinical bladder cancer tissues and in bladder cancer cell lines. The results from in vitro and in vivo assays implied that DLX6-AS1 exerted enhanced effects on bladder cancer cell proliferation, invasion and migration partly via modulating EMT and the activity of Wnt/β-catenin signaling pathway.