Cisplatin resistance driver gene CLSPN product is a target for immunotherapy in urothelial carcinoma.

Bladder cancer is a major and mortal disease in urological area. Cisplatin is a key drug for bladder cancer especially for muscle invasive cases. In most cases of bladder cancer, cisplatin is effective; however, resistance to cisplatin is critical for patient’s prognosis. Thus, treatment strategy for cisplatin resistant bladder cancer is essential to improve current prognosis. In this study, we established cisplatin resistant bladder cancer line (CR cells) using a urothelial carcinoma line UM-UC-3 cells. We screened potential targets for CR cells and found that claspin is overexpressed in CR cells. Claspin mRNA knockdown revealed that claspin has a role in cisplatin resistance in CR cells. In our previous study, we found HLA-A*02:01-restricted CLSPN peptide by an HLA ligandome analysis. We thus generated CLSPN peptide specific CTL clone and found that CLSPN peptide-specific CTL clone recognized CR cells at higher levels compared with that of UM-UC-3 wild type cells. These findings indicate that claspin is a driver for cisplatin resistance and claspin peptide-specific immunotherapy is effective for cisplatin resistant cases.