Assessing the effects of USP10 on pancreatic ductal adenocarcinoma metastasis via deubiquitinating and stabilizing RIOK3 to induce cytoskeleton remodeling.

Abstract

e16408 Background: Metastasis is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and a primary driver of its lethal nature. While Ubiquitin-Specific Protease 10 (USP10) is implicated in various cancers, its specific role and molecular mechanism in PDAC metastasis remain elusive. This study investigates the clinical significance, biological function, and downstream regulatory network of USP10 in PDAC. Methods: USP10 expression and prognostic value were analyzed using TCGA data and tissue microarrays (TMAs) from two independent cohorts (n = 136). Stable cell lines were established to assess invasion and metastasis via Transwell, wound healing assays, and a tail-vein injection lung metastasis mouse model. Interactions between USP10 and downstream targets were identified using LC-MS/MS, Co-IP, structural modeling, and domain mapping. Deubiquitination assays, cycloheximide (CHX) chase assays, and immunofluorescence were employed to dissect the molecular mechanism. A prognostic nomogram was constructed based on clinical data. Results: Clinical analysis revealed that USP10 is significantly upregulated in PDAC tissues and correlates with poor overall survival (OS). Functionally, USP10 overexpression markedly enhanced PDAC cell invasion in vitro and lung metastasis in vivo. Mechanistically, USP10 interacts with RIOK3 in the cytoplasm, specifically binding to the RIOK3 NAT domain. We demonstrated that USP10 functions as a deubiquitinase that removes K48-linked polyubiquitin chains from RIOK3, thereby stabilizing RIOK3 protein levels. This USP10-RIOK3 axis upregulates Rho and RAC1 expression, promoting F-actin cytoskeleton remodeling and a mesenchymal-like morphology; notably, RIOK3 knockdown abolished USP10-induced metastatic phenotypes. Clinically, a significant positive correlation between USP10 and RIOK3 expression was validated in both cohorts. Patients with dual high expression of USP10 and RIOK3 exhibited the worst prognosis. A nomogram incorporating the USP10-RIOK3 signature demonstrated high predictive accuracy for patient survival. Conclusions: Our findings characterize USP10 as a critical driver of PDAC metastasis through the USP10-RIOK3-Rho/RAC1 axis, which orchestrates cytoskeleton remodeling. The USP10-RIOK3 complex serves as a novel prognostic biomarker and suggests that targeting this deubiquitination axis could offer a promising therapeutic strategy for metastatic PDAC.