Preliminary Study On The Role Of FUNDC2 Expression In The Pathogenesis Of Triple Negative Breast Cancer

ObjectiveTo investigate the effect of silencing FUNDC2 on target genes of Hedgehog pathway(which is related to cell proliferation and maintenance of stemness)in Triple-Negative breast cancer(TNBC),and to explore the possibility of its mechanism as a therapeutic target for TNBC,so as to provide more references and thoughts for clinical treatment of TNBC.MethodsQuashing the clinical survival information of TNBC in TCGA databases by the survival function method(Kaplan Meier)to uncover the role of FUNDC2 on the progression free survival of TNBC patients;invitral cultured MDA-MB-231 cells were applicated as the experimental subjects,the whole genome chips were applied to screening the significantly changed genes after FUNDC2 knockout;KEGG enrichment analyses of differentially expressed genes and then we presumed that differentially expressed genes mainly affect the Hedgehog pathway.Furthermore,after FUNDC2 knockdown,m RNA and protein levels of key nodes of Hedgehog pathway were verified by RT-q PCR and Western Blot,and the downstream target GLI1 was positively correlated with FUNDC2.Correlation between mitochondrial outer membrane protein FUNDC2 and GLI1 was analyzed by tissue microarray technology.Finally,the mechanism of Fund C2 regulating downstream targets was preliminarily verified by Western Blot.Results1.The level of FUNDC2 was negatively correlated with progressionfree survival significantly in triple-negative breast cancer patients.2.Genome-wide microarray showed that significantly downregulated genes may be enriched in Hedgehog pathway after FUNDC2 silencing in MDA-MB-231 cells.3.It was verified by RT-q PCR and Western Blot that the key nodes of Hedgehog pathway were significantly down-regulated after FUNDC2 knockdown in MDA-MB-231 cells,and the most significant gene was Gli1.4.There was a significant positive correlation between FUNDC2 and GLI1 in TNBC tumor tissue(R=0.552,P <0.001).5.FUNDC2 regulated the expression of Gli1,an activator of the Hedgehog signaling pathway,through the Akt/GSK3β signaling axis.ConclusionMitochondrial outer membrane protein FUNDC2 may activate the key protein Gli1 of Hedgehog pathway through activation of its downstream signaling pathway PI3K-Akt /GSK3β,thus promoting the occurrence and development of triple negative breast cancer.