Fig. 8: The Ku binding domain in PD-L1 is essential for PD-L1 to accelerate NHEJ-mediated DSB repair and reduce IR sensitivity.
a Western blot analysis of PD-L1 using PD-L1 or Flag antibody, respectively, in H460, H460 PD-L1 KO, H460 PD-L1 KO cells expressing exogenous WT PD-L1 or PD-L1 ΔIgC mutant. b Cells were treated with 4 Gy of IR at 2 Gy/min dose rate, followed by immunofluorescence analysis of γH2AX foci and DAPI at different time points. Foci ≥5/cell were counted as foci-positive cells. Error bars represent ± s.d., n = 3 per group. ***P < 0.001, ****P < 0.0001, by two-tailed t test. c NHEJ activity was analyzed by FACS using CytekTM Aurora in various cells as indicated. Y axis represents the recovery rate of GFP from I-SceI-induced DSBs in EJ5-GFP reporter. X axis represents 7-AAD (a nucleic acid dye) staining, which was used for the exclusion of nonviable cells for quality control in flow cytometric analysis. Error bars represent ± s.d. n = 3 per group. **P < 0.01, ***P < 0.001, by two-tailed t test. d Cells were treated with IR (4 Gy), followed by colony formation assay. Error bars represent ± s.d., n = 3 per group. ***P < 0.001, by two-tailed t test. e Nu/Nu mice with various xenografts were treated with IR (2 Gy every other day, and 5 times in total). Tumor volume was measured once every 2 days. Mice were sacrificed at day 20, and tumors were removed and analyzed. Error bars represent ± s.d., n = 6 mice each group. **P < 0.01, by two-tailed t test. Source data are provided as a Source Data file.
