MiR-204 Negatively Regulates Cell Growth And Metastasis By Targeting ROBO4 In Human Bladder Cancer.

Abstract

BackgroundMicroRNAs (miRNAs) are well characterized for their important roles in human cancers by influencing various aspects of malignancy. Till now, the function and mechanism of miR-204, a tumor suppressor in several cancers, remain unclear in bladder cancer (BC). Here, we intend to explore its roles in BC progression.MethodsqRT-PCR was applied to determine miR-204 and ROBO4 expression in BC tissues and cell lines. miR-204 expression with clinicopathological features was analyzed. The impacts of miR-204 on BC cell growth and metastasis in vitro were evaluated by both loss-of-function and gain-of-function assays (CCK-8, crystal violet staining, wound healing and transwell assays). Furthermore, qRT-PCR, Western blot and luciferase reporter assays were used to validate the targeting of ROBO4 by miR-204. Finally, linear regression was performed to analyze the correlation of miR-204 and ROBO4 in BC tissues.ResultsExpression of miR-204 was markedly decreased in BC tissues and cell lines were compared with respective controls. Low miR-204 expression was associated with positive advanced T stage and lymph node metastasis. Cellular function studies revealed that miR-204 inhibited BC cell growth, migration and invasion. Mechanistic exploration found that miR-204 directly targeted ROBO4. Rescue assays indicated that ROBO4 restoration could reverse the antitumor effects of miR-204 in BC. Finally, ROBO4 was significantly correlated with miR-204 levels inversely.ConclusionmiR-204 might serve as a tumor suppressor in BC by targeting ROBO4.