MicroRNA (miR)-518-3p has been shown to function as a tumor suppressor. This study was conducted to investigate the effects of miR-518-3p in colorectal cancer (CRC). The miR-518-3p mimic, mimic negative control (NC), miR-518-3p inhibitor, inhibitor-NC, ShRNA-TRIP4, and ShRNA-NC vectors were transfected into SW480 cells using Lipofectamine 2000. Cell viability was detected using CCK-8. Colony formation, cell invasiveness, and cell migration were assessed by plate colony formation, Transwell assays, and wound healing assays, respectively. Relative mRNA and protein levels were detected using RT-qPCR and Western blot, respectively. The target gene thyroid hormone receptor interactor 4 (TRIP4) of miR-518-3p was identified and further verified using dual-luciferase reporter assay. Compared with normal tissues, levels of miR-518-3p were decreased and TRIP4 was significantly increased in the tissues from patients with CRC. Following transfection with a miR-518-3p mimic or ShRNA-TRIP4, cell viability decreased in a time-dependent manner, and colony formation rate, wound closure rate, and the number of invasive cells were much lower for the transfected cells than in the corresponding NC and control groups. miR-518-3p overexpression or silencing of TRIP4 significantly down-regulated the expression of MMP-2 and MMP-9. Knockdown of miR-518-3p had the opposite effects, and TRIP4 was identified as a target of miR-518-3p. The inhibitory effects of miR-518-3p on the progressions of CRC are associated with TRIP4.
Keywords: MMP-2/-9; TRIP4; cancer colorectal; colorectal cancer; microARN-518-3p; microRNA-518-3p.