S and G2/M arrest induced by DCQ ± IR in EMT-6 cells at 0, 2, and 4 h post-treatment. EMT-6 cells were treated at 50% confluency with DCQ (10 μM) for 4 h, and/or irradiated (10 Gy). Immediately after the 4 h-drug incubation or IR exposure, cells were replenished with media containing no drug. Cells were collected at 0 h, 2 h, and 4 h after the refreshment of media and subjected to flow cytometry. Percentages of cells in the sub-G1 (A), S (B), and G2/M (C) phases of the cell cycle were determined by CellQuest and the averages ± SD are plotted for each treatment. Dashed lines represent the % of control cells in each phase of the cell cycle. SD: standard deviation.