Assessment of radiosensitization by sunitinib using clonogenic survival assays. Sunitinib radiosensitized both DU145 (A) and PC3 (B) cells using concentrations of 100 nM for the DU145 cells and 250 nM for the PC3 cells. LnCap (C) cells were not radiosensitized with 250 nM. Cells were treated with sunitinib for 24 hrs and assessed for radiosensitization by clonogenic cell survival immediately after irradiation. Each data point represents the average of three independent experiments each plated in triplicate. * indicates p < 0.05.