Association between cellular radiosensitivity and G1/G2 checkpoint proficiencies in human cholangiocarcinoma cell lines

Cholangiocarcinoma is a destructive malignancy with a poor prognosis and lack of effective medical treat- ment. Radiotherapy is an alternative treatment for patients with unresectable cholangiocarcinoma. However, there are limited data on the radiation responsiveness of individual cholangiocarcinoma cells, which is a key factor that influ - ences radiation treatment outcome. In this study, we found that cholangiocarcinoma cell lines differ remarkably in their radiosensitivity. The variation of radiosensitivity of cholangiocarcinoma cells correlates with their p53 status and existing G1 and/or G2 checkpoint defects. We also demon- strated the potential of checkpoint kinase Chk1/2 inhibition on the enhancement of the radiosensitivity of cholangiocar- cinoma cells. Thus, this study provides useful information for predicting radiation response and provides evidence for the enchantment of radiotherapeutic efficiency by targeting checkpoint kinase Chk1/2 in some subpopulations of cholan- giocarcinoma patients.