a Western blot analysis of p-DNA-PK (S2056) in H1975-S and H1975-OR cells treated with cisplatin for 24 h. b Western blot analysis of rH2AX in H1975-OR cells treated with NU7441 (4 μM), osimertinib (4 μM), or NU7441 (4 μM) combined with osimertinib (4 μM) for 24 h. c Immunofluorescence analysis of rH2AX in H1975-OR cells treated with NU7441 (4 μM), osimertinib (2 μM), or NU7441 (4 μM) combined with osimertinib (2 μM) for 24 h. d Evaluation of DNA damage by alkaline comet assay in H1975-OR cells treated with NU7441 (4 μM), osimertinib (4 μM), or NU7441 (4 μM) combined with osimertinib (4 μM) for 24 h. e Flow cytometric analysis of the cell cycle in H1975-OR cells treated with NU7441 (4 μM), osimertinib (4 μM), or NU7441 (4 μM) combined with osimertinib (4 μM).