TRAF7 contributes to tumor progression by promoting ubiquitin-proteasome mediated degradation of P53 in hepatocellular carcinoma

It has been proved that TRAFs family proteins played malfunctioning roles in the development of human cancers. TRAF7 is the last one of TRAFs family proteins to be found, which was demonstrated to be involved in a serious of cancers development. In this study, we systematically investigated the molecular mechanisms of TRAF7 in facilitating hepatocellular carcinoma (HCC). We discovered that TRAF7 was overexpressed in tumor tissues and the increased TRAF7 expression was closely associated with tumor size, histologic grade, TNM stage and poor prognostication. TRAF7 overexpression repressed cell apoptosis and promoted cell proliferation, invasion and migration, whereas knockdown of TRAF7 in HCC cells had totally opposite effects. Besides, we identified the interaction between TRAF7 and P53 in HCC and demonstrated that TRAF7 promoted ubiquitin-proteasome mediated degradation of P53 at K48 site. The rescue assays further proved that the function of TRAF7 in inhibiting apoptosis and promoting tumor development was depended on P53 in HCC. Overall, this work identified that TARF7 promoted tumorigenesis by targeted degradation P53 for ubiquitin-mediated proteasome pathway. Targeting the TRAF7-P53 axis may provide new insights in the pathogenesis of HCC, and pave the way for developing novel strategies for HCC prevention and treatment.