CLIP170 enhancing FOSL1 expression via attenuating ubiquitin-mediated degradation of β-catenin drives renal cell carcinoma progression.

Protein interactions are fundamental for all cellular metabolic activities. Cytoplasmic linker protein 170 (CLIP170) plays diverse roles in cellular processes and the development of malignant tumors. Renal cell carcinoma (RCC) poses a significant challenge in oncology owing to its invasive nature, metastatic potential, high recurrence rates, and poor prognosis. However, the specific mechanisms and roles of CLIP170 underlying its involvement in RCC progression remain unclear. The findings of this study revealed a significant upregulation of CLIP170 in RCC tumor tissues. Elevated CLIP170 expression correlated positively with advanced clinical and pathological stages and was associated with poor overall survival in RCC patients. Functional assays in vitro demonstrated that elevated CLIP170 levels enhanced RCC cell proliferation, migration and invasion. Mechanistically, 4D-label free proteomics library identified that CLIP170 increased the level of FOSL1 in the Wnt signaling pathway. Immunoprecipitation and molecular docking were performed to unveil that CLIP170 formed a complex with β-catenin, inhibiting β-catenin degradation via the ubiquitin-proteasome pathway. Elevated β-catenin levels within RCC cells played a central role in promoting the transcriptional expression of FOSL1, thereby facilitating RCC cell proliferation and epithelial-mesenchymal transition (EMT) progression. In vivo investigations corroborated these findings, illustrating that CLIP170 regulated β-catenin and FOSL1 expression, driving tumor growth in RCC. This study highlights the crucial role of CLIP170 in promoting FOSL1 expression by preventing β-catenin ubiquitination and degradation, thus promoting RCC tumor progression. It suggests the CLIP170/β-catenin/FOSL1 axis as a potential therapeutic target for RCC treatment.