UBE2C is upregulated by estrogen and promotes epithelial-mesenchymal transition via p53 in endometrial cancer

Abstract

Ubiquitin-conjugating enzyme E2C (UBE2C) plays important roles in tumor progression; Nevertheless, its function in endometrial cancer (EC) remains unclear. This study elucidated the impact of UBE2C on EC and its underlying mechanism. Human EC and normal endometrial tissues were acquired from patients at Wuhan Union Hospital and UBE2C expression was detected by western blotting and quantitative real-time polymerase chain reaction. EC cells were transfected with a UBE2C overexpression plasmid or UBE2C-specific shRNAs to up- or down-regulate UBE2C expression, respectively. CCK8 and transwell assays were applied to assess the effects of UBE2C on cell proliferation, migration, and invasion. We found a significant elevation of UBE2C expression in patients with EC, and that UBE2C upregulation was associated with advanced histological grade, FIGO stage, recurrence, and shorter overall survival. UBE2C knockdown inhibited EC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT), whereas UBE2C overexpression exerted the opposite effects. UBE2C downregulation increased p53 and its downstream p21 expression, with p53 overexpression reversing the EMT-promoting effects of UBE2C. UBE2C enhanced p53 ubiquitination to facilitate its degradation in EC cells. Estradiol (E2) induced UBE2C expression via estrogen receptor (ER)α, which binds directly to the UBE2C promoter element. Silencing of UBE2C inhibited E2-promoted migration, invasion, and EMT in vitro and in vivo. Implications: UBE2C-mediated tumor EMT promotion by estrogen is a novel mechanism for the progression of estrogen-induced EC, which could offer new biomarkers for diagnosis and therapy of EC in the future.