Fig. 3: miR-200c-3p decreases radiation-resistant cell survival by delaying DNA repair.

A Radiation clonogenic survival assays were performed on radioresistant DU145 (DU145 RR) cells transiently transfected with control (miR-neg) or miR-200c-3p mimic. Means and SEM are represented. Wilcoxon test one side at 6 Gy DU145 RR vs DU145+miR-200c-3p or vs DU145: ***p < 0.001, n > 4, RPF radiation protection factor. B Viability test of DU145 radioresistant cells transfected with control or miR-200c-3p mimic. Twenty-four hours after the transfection, the cells were irradiated with 6 Gy before measuring the viability of the cells 24 hours later with a Cell-Titer Glo kit. The luminescence was expressed relative to that in the miR-neg condition. Wilcoxon test one side, **p < 0.01, n = 5. C Representative images of confocal microscopy images for the detection of γ-H2AX foci and 53BP1 foci. Nuclei were stained with Hoechst (blue). In green, the phosphorylation of S139 (γ-H2AX) of histone H2AX, in red 53BP1 protein, in DU145 RR cells transfected with miR-neg or miR-200c-3p, at 30 min, 6 h or 24 h after irradiation at 6 Gy. White bar = 10 μm. D Plot of the number of γ-H2AX foci number per cell. For each condition, more than 50 cells were analyzed per replicat, n = [5–7], Wilcoxon test one side, *p < 0.05. E Plot of the number of 53BP1 foci number per cell. For each condition, more than 50 cells were analyzed per replicat, n = [4–5], Wilcoxon test one side, *p < 0.05.