LncRNA TUG1 promotes bladder cancer malignant behaviors by regulating the miR-320a/FOXQ1 axis

Growing evidence has showed long noncoding RNAs (lncRNAs) play critical roles in bladder cancer (BC) progression. LncRNA taurine upregulated gene 1 (TUG1) was involved in the development of human malignancies. However, the intrinsic and concrete molecular mechanisms of TUG1 in BC remain largely unknown.Expression patterns of TUG1, miR-320a and FOXQ1 in BC tissues and cell lines were measured using qRT-PCR and western blot, respectively. Cell proliferation was detected by CCK-8 and colony formation assays. The capacity of cell migration and invasion was evaluated using wound healing and transwell assay. Tumor xenograft assay was performed to further validate the role of TUG1 in BC progression. Dual luciferase reporter assay and FISH analysis were employed to verify the TUG1/miR-320a/FOXQ1 regulatory network.TUG1 was significantly higher expression in BC specimens and cell lines. TUG1 knockdown suppressed BC cells malignant behaviors in vitro and inhibited tumor growth and metastasis in vivo, while TUG1 overexpression promoted BC cells malignant behaviors in vitro. However, the function of miR-320a was opposite to that of TUG1, and miR-320a inhibitor partially eliminated the inhibitory effect of TUG1 knockdown on the malignant behavior of BC cells. As a microRNA sponge, TUG1 actively elevated FOXQ1 expression to sponge miR-320a and subsequently promoted BC cells malignant phenotypes.TUG1 may have great potential as therapeutic target for BC, since TUG1 silencing inhibited cell proliferation, migration and invasion in BC, while promoted cell apoptosis, by regulating the miR-320a/FOXQ1 axis.