miR-92b-3p Promotes Colorectal Carcinoma Cell Proliferation, Invasion, and Migration by Inhibiting FBXW7 In Vitro and In Vivo.

microRNA (miR)-92b is an oncogenic miRNA. F-box and WD-40 domain protein 7 (FBXW7/hCdc4) is a tumor suppressor and a target of miR-92b-3p. This study was designed to investigate the effect of miR-92b-3p on colorectal carcinoma (CRC) invasion. The expression levels of miR-92b-3p in human HT29, HCT116, and human fetal colon (FHC) normal cells were detected. HT29 and HCT116 cells were transfected with either miR-92b-3p inhibitor or FBXW7 expression plasmids (pcDNA-FBXW7) and combination of miR-92b-3p and siRNA-FBXW7. Cell viability, migration, invasion, colony formation, cell cycle, and apoptosis in transfected cells were detected using corresponding methods. Moreover, the target relationship between miR-92b-3p and FBXW7 was verified using dual-luciferase reporter assay. miR-92b-3p was upregulated in CRC cells in comparison with FHC cells. Then, we transfected HT29 and HCT116 cells with miR-92b-3p inhibitor or pcDNA-FBXW7 and found decreased cell proliferation, migration, invasion, and colony formation ability, as well as the number of upregulated cells at G1 phase of cell cycle and cell apoptosis. With the cotransfection of miR-92b-3p inhibitor and siRNA-FBXW7, we determined that siRNA-FBXW7 partially attenuated the effect of miR-92b-3p inhibitor on cell behaviors. SiRNA-FBXW7 administration to miR-92b-3p inhibitor-treated cells rebooted cell proliferation, cell migration, invasion, and colony formation. miR-92b-3p inhibition prevented CRC proliferation, invasion, and migration by upregulating FBXW7, which might suggest the potential role of miR-92b-3p in colorectal carcinogenesis and metastasis.