Figure 1

Radiation sensitivities of hormone-sensitive and HR prostate cancer. (a) Cells (TRAMP-C1 and TRAMP-HR) were irradiated with 0, 3, 6, or 9 Gy, and the survival curves were determined by colony-formation assay. The survival fraction was determined by enumerating colonies after irradiation exposure divided by the plating efficiency; (b) Tumor growth delay of irradiated ectopic tumors. The radiosensitivity is shown as growth delay after 15-Gy irradiation. HR tumors appeared more radioresistant, as shown by the shorter growth delay. Y-axis shows the ratio of tumor volume at each time point divided by that at irradiation respectively. Each point is the mean of three independent experiments; bars, SD. *, P < 0.05. (c) The intracellular ROS level was measured, using the fluorescent dye DCFH-DA, in prostate cancer cells either untreated or 30 min after 9-Gy irradiation. Y-axis represents the relative level, normalized to the level of ROS in TRAMP-C1 under control conditions. (d) Flow cytometric analysis using Annexin V staining for apoptosis in prostate cancer cells, either without irradiation or 24 h after 9-Gy irradiation.