MiR-592 inhibited cell proliferation of human colorectal cancer cells by suppressing of CCND3 expression

Accumulating evidence shows that microRNA (miRNA) is frequently associated with multiple kinds of human cancers, including colorectal cancer (CRC). Previous studies have shown that miR-592 play critical roles in cancer cell biological processes. However, the function of miR-592 in CRC remains largely unknown. In the present study, we investigated the miR-592's role in cell proliferation of colorectal cancer. MiR-592 expression was markedly down-regulated in CRC tissues and CRC cells. Overexpression of miR-592 reduced the proliferation and anchorage-independent growth of CRC cells. Furthermore, bioinformatics analysis further revealed CCND3, a putative tumor promoter, was found to be a potential target of miR-592 in CRC. The dual-luciferase reporter gene assay results showed that CCND3 was a direct target of miR-592. Ectopic expression of miR-592 led to down-regulation of CCND3 protein, which resulted in the down-regulation of phosphorylated retinoblastoma (p-Rb). In functional assays, CCND3-silenced in miR-592-in-transfected SW48 cells have positive effect to suppress cell proliferation, suggesting that direct CCND3 suppression is required for miR-592-induced cell proliferation of CRC. We conclude that miR-592 can regulate CCND3 and function as a tumor suppressor in CRC. Therefore, miR-592 represents a potential anti-onco-miR and serves as a useful therapeutic agent for miRNA-based CRC therapy.