ITCH-Mediated Ubiquitylation of ITGB3 Promotes Cell Proliferation and Invasion of Ectopic Endometrial Stromal Cells in Ovarian Endometriosis

Post-translational modification of proteins is involved in the occurrence of endometriosis (EM); however, the role of ubiquitination modification in EM remains unclear. Integrin β3 (ITGB3) is one of the β-subunits of integrins, which plays a key role in tumor progression. In this study, we investigated the roles of ITGB3 and ITCH, one of the ubiquitin E3 ligases, in ectopic endometrial stromal cells (ESCs) and EM. Primary ectopic ESCs and normal ESCs were isolated and purified. Western blot was used to detect the expression of ITGB3 and ITCH in ESCs. The interaction between ITGB3 and ITCH in ESCs was investigated by the co-immunoprecipitation and ubiquitylation analysis. With or without the overexpression of ITCH and/or ITGB3, the proliferation and invasion of ectopic ESCs were detected by the CCK8 assay and transwell migration assay, respectively. We found that ITGB3 is upregulated in ectopic ESCs from patients with EM. ITCH interacts with ITGB3 by co-immunoprecipitation, and ITCH-overexpressing significantly increased the ubiquitination of ITGB3. The data of the CCK8 assays showed that ITGB3 overexpression significantly promoted cell proliferation of ectopic ESCs at 12, 24, 48, and 72 h. The transwell migration assays showed that ITGB3 overexpression significantly enhanced the invasive ability. However, ITCH had the opposite effects in both assays. Our findings indicate that ITCH-mediated ubiquitylation of ITGB3 regulates the proliferation and invasion ability of ectopic ESCs in EM.