Overexpression of miR-92a promotes the tumor growth of osteosarcoma by suppressing F-box and WD repeat-containing protein 7

Abstract

MicroRNAs (miRNAs) have been reported to be critical players in osteosarcoma (OS). Among numerous cancer-related miRNAs, the expression level of miR-92a and its potential role in OS has not been investigated. Here, We showed that overexpression of miR-92a was identified in OS specimens and cells compared to normal bone tissues. The high level of miR-92a was correlated with high T classification and advanced clinical stages of OS patients. Notably, miR-92a highly expressing OS patients showed a notably reduced survival rate. In vitro experiments showed that loss of miR-92a inhibited U2OS cell proliferation and cell-cycle progression while induced apoptosis. In turn, its restoration facilitated MG-63 cell growth and suppressed apoptosis. Experimental nude mice showed that miR-92a silencing prohibited the in vivo growth of OS cells. Furthermore, bioinformatics software predicted that F-box and WD repeat-containing protein 7 (FBXW7) was a direct target of miR-92a. We then observed the negative regulation of miR-92a on FBXW7 expression and the direct binding between them was further verified by dual-luciferase assays in OS cells. Forced expression of FBXW7 resulted in reduced proliferation, cell cycle arrest at G1 phase and increased apoptosis in miR-92a overexpressing MG-63 cells. In summary, this study demonstrates miR-92a probably functions as a driver of tumor progression by targeting FBXW7, and highlights the potential effects of miR-92a on prognosis and treatment of OS.