Mechanism of cell death after combined radiation and AZD4547 treatment in NCI-H226 and NCI-H1581 cell lines. Cells were treated with DMSO, AZD4547 (0.1 μM), radiation (3 Gy), or combined AZD4547 (0.1 μM) and radiation (3 Gy) and analyzed at designated time points. (A) Annexin V apoptosis, (B) acridine orange autophagy, and (C) cell cycle arrest analysis. Columns, mean; bars, SEM (n=3). *, P < 0.01, according to t test (irradiation versus AZD4547 plus irradiation).