Radiosensitization of tumor by caffeine encapsulated in liposomes

초록

It has been known that ATM palys a central role in response of cells to ionizing radiation by enhancing DNA repair. We hane investigated the possibility of increasing radiosensitivity of tumor cells with the use of ATM inhabitors such as caffeine. Human colorectal cancer RKO.C cells and RKO/ATM cells (RKO cells overexpressing ATM) were used in the present study. The clonogenic cell survival in vitro indicated tha RKO/ATM cells were markdely radioresistant as compared to RKO.C cells. Presence of 3 mM of caffeine significantly increased the radiosensitivity of cells, particulary the RKO/ATM cells was clmost similar. The radiation induced G2/M arrest in RKO/ATM cells was noticeably longer than that in RKO.C cell and caffein treatment shortened the radiation induced G2/M arrest in both RKO.C and RKO/ATM cells.