Protection of Human Tumor Cells of Differing Radiosensitivity by WR-1065

Abstract Murray, D., Rosenberg, E. and Allalunis-Turner, M. J. Protection of Human Tumor Cells of Differing Radiosensitivity by WR-1065. We examined the ability of WR-1065, the biologically active aminothiol form of the clinically used drug amifostine (WR-2721, Ethyol®), to protect cultures of two human glioblastoma cell lines of greatly differing radiosensitivity from the cytotoxic effects of γ radiation. M059J cells are extremely radiosensitive compared to M059K cells (which were derived from the same tumor) and are defective in the DNA-dependent protein kinase (DNAPK)-mediated pathway for the repair of DSBs. In spite of their marked phenotypic differences, the two glioblastoma lines were protected equivalently (∼1.8-fold) after a 30-min preirradiation treatment with 4 mM WR-1065. These findings are in agreement with earlier studies that showed no relationship between the ability of another aminothiol, cysteamine, to protect human tumor cells with differing abilities to repair DSBs and/or radiosensitivi...