Fig. 6: Radiation-resistant CAV1(+) PC3 cells are characterized by higher levels of total ceramide, which correlated with an increased ASMase activity.

CAV1-proficient [CAV1(+)] and CAV1-deficient [CAV1(−)] PC3 PCa cells were subjected to radiation treatment (0-Gy control or 10 Gy). a Apoptotic cells (sub-G1) were analyzed by flow cytometry 48 h after irradiation. Graphs consist of data from 3 to 4 individual experiments (with SEM). **p < 0.01 by two-way ANOVA with post hoc Sidak’s multiple-comparison test. b Different expression of ceramide species was measured by LC–MS in CAV1(+) and CAV1(−) PC3 cells. Bars represent the mean of three individual experiments with SEM. Statistical analysis was performed using two-way ANOVA followed by post hoc Sidak’s test (****p < 0.001). c The ratios of saturated to unsaturated ceramide C16–C24:1 and C24–C24:1 were calculated in CAV1(+) and CAV1(−) PC3 cells. The results are shown of three individual experiments with SEM. Statistical analysis was performed using Student’s t test with Welch’s correction. p Value indicates ****p < 0.001. d ASMase activities of differential CAV1-expressing PC3 cells were measured at control conditions. Activities are shown in relation to CAV1(+) cells set as 1 (n = 4, SD). p Value indicates ***p < 0.001 and was analyzed by Student’s t test with Welch’s correction. e Timeline of indicated ceramide species as well as total ceramide levels generated by CAV1(+) and CAV(−) PC3 cells after IR treatment. Samples were taken 1, 5, 15, and 30 min after 10-Gy irradiation (n = 3, SD).