The Association Between Gelsolin-like Actin-capping Protein (CapG) Overexpression and Bladder Cancer Prognosis

Abstract

PURPOSE: Muscle-invasive bladder cancer (MIBC) is associated with disease progression and metastasis leading to poor prognosis. Current chemotherapy approaches have not adequately increased patient survival. Therefore, in this study, tissue proteome of patients with MIBC was performed to introduce possible protein candidates for bladder cancer prognosis as well as targeted therapy. MATERIALS AND METHODS: The tumoral and normal adjacent bladder tissues were obtained from patients diagnosed with bladder cancer. Two-dimensional gel electrophoresis (2-DE) and liquid chromatography-mass spectrometry (LC-MS/MS) were used to analyze tissue proteome. CAPG protein was further examined using Real-time PCR and western blot analysis. RESULTS: The 2-DE analysis and LC-MS/MS identified Gelsolin-like Actin-capping (CAPG) protein as differentially expressed protein in tumor tissues of bladder cancer compared with normal adjacent tissues. Western blot analysis showed the CAPG overexpression in tumor tissues compared with normal adjacent tissues in a stage-dependent manner. Correspondingly, Real- time PCR showed a higher mRNA expression in tumoral bladder tissues than normal adjacent ones. CAPG mRNA overexpression had significantly a positive relation with tumor size (p = 0.019), the TNM staging (p = 0.001), and tumor differentiation (grade) (p = 0.006). Patients with lower levels of CAPG had higher recurrence-free survival in comparison with patients with higher level of CAPG (p = .027). CONCLUSION: CAPG overexpression was correlated with size, stage, grade, and shorter time to recurrence of tumor. Therefore, CAPG overexpression could be related to poor prognosis of bladder cancer. These results suggest that CAPG may be considered as a prognostic factor and also for targeted therapy in bladder cancer