MicroRNA-185 is a novel tumor suppressor by negatively modulating the Wnt/β-catenin pathway in human colorectal cancer

OBJECTIVE: The deregulation of microRNA-185 (miR-185) has been showed to be associated with many cancers and act as a tumor suppressor in many types of human malignancies. We hence tried to find out its role in human colorectal cancer (CRC). MATERIALS AND METHODS: miR-185 expression was investigated by real-time quantitative polymerase chain reaction. We carried out transfections to overexpress or knockdown of miR-185 by mimics or inhibitor, respectively. Functional study like cell counting kit-8 assay was performed to evaluate the proliferation. For addressing the impact of miR-185 on Wnt/-catenin signaling, we further applied luciferase reporter assay and Western blotting for specific proteins in this pathway. RESULTS: miR-185 was decreased in CRC cell lines when compared with corresponding control cell line. We also proved that its overexpression in LoVo cells could remarkably suppress cell proliferation whereas knocked it down in SW480 cells has the opposite effect in vitro. Mechanically, we demonstrated that miR-185 could suppress the Wnt/-catenin signaling and modulate the transcription and translation level of downstream molecules of this pathway, including MYC and CCND1. CONCLUSION: Taken together, these results suggested that miR-185 exerts its tumor suppressor activities probably through a negative modulation of the Wnt/-catenin pathway.