Fig. 2: Supplementing nucleoside pools promotes DNA repair and RT-resistance in GBM.

a A schematic timeline of treatment in the RT-sensitive cell lines. U118 MG, DBTRG-05MG, or GB-1 cells were treated with exogenous pooled nucleosides (Nuc; 8×) for 24 h, and retreated with nucleosides 2 h before RT with indicated doses, followed by IF, comet assay, or clonogenic assay. b–d U118 MG, DBTRG-05MG, and GB-1 cells were treated as described in Fig. 2a, followed by clonogenic assay. ER indicates the Enhancement Ratio, which is the ratio of Dmid control and Dmid treatment. ER > 1 indicates radiosensitization while ER < 1 indicates radioprotection. Fig. b–d show representative figures from one of three biologic repeats for each cell line, each performed in technical triplicate. Error bars indicate mean ± SEM from technical triplicates from that single representative experiment. In the lower left of each graph, ER (mean ± SEM) from the three biologic replicates is shown. e–g Cells were treated as above and harvested for γ-H2AX foci IF staining at indicated times post-RT. Data are presented as mean ± SEM from 3 biologically independent experiments. p values of 0.5, 2, 6, and 24 h are 0.0021, 0.0050, 0.0044, and 0.0035 for Fig. e; 0.0071, 0.0134, 0.0069, and 0.0056 for Fig. f; 0.0140, 0.0007, 0.0093, and 0.0035 for Fig. g–i. DBTRG-05MG or GB-1 cells were treated as above and harvested at different time points for alkaline comet assay. Cells were irradiated and harvested on ice for the 0 h time point (4 Gy; 0 h). Data are presented as mean ± SEM from 3 (h) or 4 (i) biologically independent experiments. p values of 0, 0.5 and 4 h are 0.4996, 0.0019, and 0.0145 for Fig. h; 0.8050, 0.0152, and 0.0080 for Fig. i. Fig. e–i: *p < 0.05 and **p < 0.01, ***p < 0.001 compared with control. The p values indicated in Fig. e–i were obtained by two-tailed unpaired student's t test. Source data are provided as a Source Data file.