TRAF7 inhibits proliferation and migration of esophageal squamous cell carcinoma by ubiquitination-mediated degradation of SOX12.

Abstract

Tumor necrosis factor receptor-associated factor 7(TRAF7), a member of the tumor necrosis factor receptor (TNF-R) superfamily, is known as an E3 ubiquitin ligase and has been shown to contribute to the progression of various cancers. However, the function of TRAF7 in esophageal squamous cell carcinoma (ESCC) remains unclear. Here, our findings demonstrate a marked downregulation of TRAF7 protein expression in esophageal squamous cell carcinoma (ESCC) cell lines compared to non-neoplastic esophageal epithelial cells. Overexpression of TRAF7 inhibited cell proliferation and migration of ESCC cells, as well as promoted cell apoptosis and blocked cell cycle at the G2/M phase. In this study, we observed that TRAF7 interacted with the SOX12 protein and promoted ubiquitin-proteasome-mediated degradation of SOX12 via K48-linked ubiquitination in ESCC cells. Rescue experiments further confirmed that TRAF7's inhibitory effects on tumor cell proliferation and migration in ESCC cells partly depended on SOX12. In summary, our research reveals that TRAF7 functions as a tumor suppressor partially by promoting K48-linked ubiquitination-mediated degradation of the SOX12 protein.