Cathepsin C Promotes Tumorigenesis in Bladder Cancer by Activating the Wnt/β-catenin Signalling Pathway

Background: Cathepsin C (CTSC) participates in the development of numerous cancers; however, its function in bladder cancer (BCa) remains largely unknown.Methods: Bioinformatics prediction, quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay, and Western blot assay were used to determine CTSC expression in BCa tissues, paracancer tissues, BCa cells, and normal uroepithelial cells (SV-HUC-1). Colony formation, cell counting kit-8 (CCK-8), and Transwell assays were utilised to ascertain the involvement of CTSC in BCa. The effect of CTSC on BCa was further studied in vivo via animal experiments.Results: CTSC exhibited a heightened expression in BCa cells and tissues; meanwhile, bladder urothelial carcinoma (BLCA) patients with enhanced CTSC expression had a remarkably reduced overall survival than those with low CTSC expression. The overexpression of CTSC substantially enhanced the activity, proliferation, migration, and invasion of BCa cells, whereas its suppression repressed the above biological phenotypes. CTSC could activate the Wnt/beta-catenin signalling pathway and upregulate diaphanous-related formin 3 (DIAPH3). CTSC overexpression combined with DIAPH3 knockdown partially reversed the impact of CTSC overexpression on the biological behaviour of BCa cells and the activation of the Wnt/beta-catenin signalling pathway.Conclusions: CTSC was upregulated in tissues and BCa cells, and high CTSC expression was associated with poor overall survival. CTSC could enhance the activity, proliferation, migration, and invasion of BCa cells via upregulating DIAPH3 and activating the Wnt/beta-catenin pathway.