MicroRNA-4476 Promotes Glioma Progression Through A MiR-4476/APC/?-catenin/c-Jun Positive Feedback Loop

Background:The adenomatous polyposis coli(APC)protein is an essential negative regulator of Wnt/?-catenin signaling,and aberrant activation of the Wnt/?-catenin signaling pathway is frequently observed in tumors,including gliomas.Numerous miRNAs are reported to activate Wnt/?-catenin signaling and promote cancer progression by targeting APC;however,whether miRNA-4476 and APC interact in glioma,and the potential roles of this interaction,remains unknownMethods:Real-time PCR and in situ hybridization were performed to examine the expression of miR-4476,while the expression of APC and c-Jun were examined by immunohistochemistry.MTT and EdU assays were performed to test cell proliferation,Transwell and Boyden assays were used to test the migratory and invasive capacity of glioma cells in vitro,and tumorigenicity was evaluated by subcutaneous tumor formation experiments in nude mice.Western Blotting was used to examine the molecular mechanism by which miR-4476 regulates glioma progression.Dual-luciferase reporter assays were used to confirm that APC is a miR-4476 target gene.ChIP,EMSA,and dual-luciferase assays were designed to verify that c-Jun binds to the miR-4476 promoter regionResults:We found that miR-4476 was upregulated in glioma,and promoted cell proliferation,migration,and invasion of glioma cells.Mechanistic analyses indicated that APC is a direct target of miR-4476,and mediates the oncogenic effects of miR-4476 in glioma.c-Jun,a downstream effector of the Wnt/?-catenin signaling pathway,positively regulated miR-4476 expression through binding to its promoter.Furthermore,in clinical samples from glioma patients,we found that increased miR-4476 expression is an unfavorable prognosis factor for glioma patients,and miR-4476 expression was positively correlated with c-Jun expression,but negatively correlated with that of APC.Conclusions:In this study,we revealed a novel mechanism by which miR-4476 promotes glioma progression through a miR-4476/APC/?-catenin/c-Jun positive feedback loop,identifying miR-4476 as a potential prognostic marker and therapeutic target for the treatment of glioma.