USP1 Promotes Malignant Progression of Cervical Cancer Cells by Deubiquitinating and Stabilizing ATG13 to Enhance...

Autophagy is an evolutionarily conserved lysosomal degradation pathway that exerts context-dependent regulatory effects on tumorigenesis and development. Ubiquitin-specific protease 1 (USP1) has been identified as an oncogenic driver in multiple malignant tumors, yet its specific biological function in cervical cancer, especially its regulatory crosstalk with autophagy, remains largely unexplored. Immunohistochemistry, qRT-PCR, and Western blotting were used to examine USP1 expression in cervical cancer tissues and cell lines. A series of biological assays including CCK-8, colony formation, Transwell, and flow cytometry were conducted to explore the impacts of USP1 silencing on cell proliferation, migration, invasion, and apoptosis. Autophagic flux was monitored by LC3 immunofluorescence staining and Western blotting of autophagy-related markers. Co-immunoprecipitation and in vitro ubiquitination assays were used to clarify the interaction between USP1 and ATG13 and the deubiquitination effect of USP1 on ATG13. Rescue experiments with ATG13 overexpression combined with or without the USP1 inhibitor ML323 were performed to verify the functional regulatory axis of USP1-ATG13-autophagy. In addition, a xenograft mouse model was established by subcutaneously injecting SiHa cells stably expressing sh-USP1 and/or ATG13-overexpressing lentivirus into nude mice; tumor volume and weight were assessed 4 weeks post-injection. USP1 exhibited markedly elevated expression in both cervical cancer tissues and cell lines, and its overexpression was strongly associated with high pathological grades of cervical cancer. Functional assays revealed that silencing USP1 observably suppressed the proliferation, migration, and invasion of C33A and SiHa cells, and simultaneously promoted cellular apoptosis. Mechanistically, USP1 could directly bind to ATG13 and mediate its deubiquitination, thereby enhancing the protein stability of ATG13 and promoting the autophagic flux of cervical cancer cells. Notably, overexpression of ATG13 could reverse the inhibition of autophagy and the suppression of malignant phenotypes induced by USP1 knockdown, and this rescue effect was completely abrogated by ML323 treatment. In vivo xenograft experiments confirmed that USP1 knockdown significantly inhibited cervical cancer tumor growth, while ATG13 overexpression markedly rescued the tumor-suppressive effect induced by USP1 silencing. Our study reveals a novel molecular mechanism by which USP1 promotes the malignant progression of cervical cancer through stabilizing ATG13 and subsequently enhancing autophagic activity. USP1 may serve as a promising therapeutic target for cervical cancer, and modulation of autophagy holds clinical potential in cervical cancer intervention.