Molecular Mechanism Of LINC00461 Regulating HSP90/c-Myc Axis To Inhibit C-Myc Ubiquitination And Promote Glucose Metabolism And Proliferation In Triple Negative Breast Cancer

Objective:To investigate the function and mechanism of LINC00461 in triple negative breast cancer(TNBC).Methods:TNBC cell lines MDA-MB-231 and MDA-MB-468 were cultured in vitro.The cells were stably cultured by RNA interference and lentivirus infection.The expressions of LINC00461 and c-Myc in MDA-MB-231 and MDA-MB-468 cells were detected by qRT-PCR.The amount of apoptosis was discovered using flow cytometry.ECAR and lactic acid production test were used to detect the changes of aerobic glycolysis.Western blot was used to detect the expression of apoptosis related proteins,HSP90,HIF-1α,P53 and c-Myc.FISH assay confirmed the cell location of LINC00461.CHIRP,PRM and RIP assays were used to detect the interaction between LINC00461 and HSP90.The functional sites of LINC00461 were detected by RNA pulldown assay.The interaction between HSP90 and c-Myc was detected by CDIP assay.The effect of LINC00461 on the level of c-Myc ubiquitination was detected by ubiquitination assay.The effect of LINC00461 on the growth of TNBC in vivo was detected by constructing a nude mouse model of transplanted tumor.Results:1)In MDA-MB-231 and MDA-MB-468 cells,the expression,efficiency of LINC00461 was significantly decreased after silencing,and its overexpression was significantly increased(P<0.05);2)LINC00461 promoted cell proliferation and glucose metabolism,and inhibited apoptosis(P<0.05);3)LINC00461(1423-2384bp)interacted with HSP90,affected the interaction between HSP90 and c-Myc,and positively regulated c-Myc.At the same time,transfection of c-Myc could affect the cell function of LINC00461 on TNBC(P<0.05);4)LINC00461 protects c-Myc from ubiquitination and degradation;5)The subcutaneous tumorigenesis assay in nude mice showed that overexpression of LINC00461 increased the volμMe and weight of the transplanted tumor,and the expression of c-Myc protein increased.Interference with c-Myc could reserve the effect of overexpression of LINC00461 on the volume and weight of the transplanted tumor.Conclusion:LINC00461 acts as a guide molecule to affect the interaction between HSP90 an.d c-Myc and inhibit the ubiquitination level of c-Myc,thereby regulating TNBC proliferation,apoptosis and glucose metabolism.