Upregulation of Long Noncoding RNA TUG1 Promotes Bladder Cancer Cell Proliferation, Migration, and Invasion by Inhibiting miR-29c

Abstract

Bladder cancer (BC) is one of the leading causes of cancer-related deaths in the world. Long noncoding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) plays an important role in the development and progression of numerous cancers, including BC. However, the exact role of TUG1 in modulating BC progression is still poorly known. In this study, we found that TUG1 was upregulated and microRNA-29c (miR-29c) was downregulated in BC tissues and cell lines. Overexpression of TUG1 promoted the cell proliferation of T24 and EJ cells, whereas TUG1 knockdown had the opposite effect. Upregulation of TUG1 obviously facilitated the migration and invasion of T24 and EJ cells. In contrast, TUG1 silencing repressed the migration and invasion of T24 and EJ cells. Furthermore, TUG1 knockdown markedly increased the expression of miR-29c in vitro. On the contrary, overexpression of TUG1 remarkably decreased the expression of miR-29c. Transfection with plasmids containing mutant TUG1 has no effect on the expression of miR-29c. There were direct interactions between miR-29c and the binding sites of TUG1. In addition, the inhibitory effects of small interfering RNA specific for TUG1 on BC cell proliferation, migration, and invasion were reversed by downregulation of miR-29c. Collectively, our study strongly demonstrates that TUG1 promotes BC cell proliferation, migration, and invasion by inhibiting miR-29c, suggesting that lncRNA TUG1 may be a promising target for BC gene therapy.