Study on the mechanism of USP7 promoting endometriosis by regulating DNMT1 deubiquitination level

Endometriosis is characterized by aberrant epigenetic regulation, and our study reveals that both Ubiquitin Specific Protease 7 (USP7) and DNA methyltransferase 1 (DNMT1) are significantly overexpressed in endometriosis tissues. Functional analyses in ectopic endometrial stromal cells (EESCs) indicate that elevated USP7 levels markedly enhance cellular proliferation, migration, and invasion, whereas silencing DNMT1 mitigates these oncogenic properties. Notably, USP7 and DNMT1 co-localize within the nucleus and interact directly, with USP7 modulating DNMT1 stability by attenuating its ubiquitination. The reduction in DNMT1 protein levels following USP7 silencing was reversed by proteasome inhibition, underscoring the pivotal role of USP7-mediated deubiquitination in maintaining DNMT1 stability. Furthermore, treatment with the USP7 inhibitor FT-671 significantly reduced DNMT1 protein expression while leaving its mRNA levels unaffected, and FT-671 effectively suppressed EESCs proliferation, migration, and invasion. Collectively, these findings suggest that USP7 contributes to the pathogenesis of endometriosis by sustaining DNMT1 expression and promoting aberrant cellular behaviors, thereby representing a promising therapeutic target for this disease.