UBP43 promotes epithelial ovarian carcinogenesis via activation of β-catenin signaling pathway

Dysregulation of the deubiquitinating protease, UBP43, has been implicated in many human diseases, including cancer. Here, we evaluated the functional significance and mechanism of action of UBP43 in epithelial ovarian cancer. We found that UBP43 was significantly upregulated in the tumor tissues of patients with epithelial ovarian cancer. Similar results were observed in OVCAR-3, Caov-3, TOV-112D, A2780, and SK-OV-3 cells. Furthermore, in vitro functional assays of A2780 and TOV-112D cells demonstrated that UBP43 overexpression promoted cell proliferation, migration, and invasion. Upregulation of UBP43 might result in epithelial-mesenchymal transition by inducing the nuclear transport of β-catenin, which was accompanied by enhanced N-cadherin but decreased E-cadherin expression. These malignant phenotypes were reversed by UBP43 silencing. Further investigation revealed that the knockdown of UBP43 inhibited cell proliferation by inducing a cell cycle arrest at the G2/M phase. The oncogenic characteristics of UBP43 were validated in a subcutaneous xenograft mouse model. In vivo, tumor growth was delayed in the UBP43-silenced group but accelerated after UBP43 overexpression. Finally, we demonstrated that β-catenin is a key protein in the UBP43-mediated malignant development of epithelial ovarian cancer. Specifically, overexpression of UBP43 decreased the ubiquitination degradation of β-catenin and enhanced its protein stability. Also, we observed that the downstream genes of beta-catenin such as cyclin D1, MMP2, and MMP9 were upregulated due to UBP43 overexpression. Thus, we concluded that UBP43 promoted epithelial ovarian cancer tumorigenesis and metastasis through activation of the β-catenin pathway, suggesting that UBP43 may be a potential therapeutic target for this intractable disease.