Cdc20 induces the radioresistance of bladder cancer cells by targeting FoxO1 degradation

Abstract Ionizing radiation is a conventional therapy for cancer patients, but patients often experience distant metastasis and recurrence, which lead to a poor prognosis after the implementation of this treatment. Moreover, the underlying mechanisms by which radioresistance contributes to metastatic potential is still elusive. Here, we explored the molecular mechanisms that contribute to radioresistance in bladder cancer. To achieve this, we established two irradiation-resistant (IR) cell lines, T24R and 5637R, which were derived from parental bladder cancer cell lines. Cell viability was detected by CCK-8 assay, while migration and invasion abilities were examined by wound healing and Transwell chamber assays, respectively. Furthermore, the role of Cdc20 in the regulation of epithelial to mesenchymal transition (EMT) in IR cells was explored by Western blotting, immunoprecipitation and immunofluorescence staining. The IR cells exhibited EMT properties, and our data showed that Cdc20 expression was significantly elevated in IR cells. Remarkably, Cdc20 silencing reversed the EMT phenotype in IR cells. Mechanistically, Cdc20 governed IR-mediated EMT in part by governing forkhead box O1 (FoxO1) degradation. Taken together, our findings showed that the inactivation of Cdc20 or the activation of FoxO1 might be a potential strategy to overcome radioresistance in bladder cancer.