Blockade of radiation-induced mTOR phosphorylation by AZD8055 enhances radiation induced cell cycle arrest and apoptosis. (A) PANC-1 cells were treated with radiation (5 Gy) in the absence or presence of AZD8055 (500 nM) for 24 h, followed by analysis of cell cycle by flow cytometry. The cells in G0/G1, S and G2/M phases were presented in the percentage. The experiment was repeated three times and the percentages of cells in G0/G1 and S phases were presented as mean ± SD. (B) Annexin-V/PI cell apoptosis analysis of PANC-1 cells treated with radiation in the absence or presence of AZD8055 for 24 h, flow cytometry data showed the percentage of apoptotic cells The experiment was repeated three times and the percentage of apoptotic cells was presented as mean ± SD. **, P < 0.01 vs. IR treatment alone.