Cells were either untreated or treated with 40 μM SF1126 for 48 h, at which point they were fixed and stained with propidium iodide. DNA content was then analyzed by flow cytometry. Representative cell cycle profiles are shown for (A) SK-parental and SK-HRp2, and (B) BT-parental and BT-HRp3 cells. The percentages of (C) SK-parental and SK-HRp2cells, and (D) BT-parental and BT-HRp3 cells in G0/G1, S, or G2/M are shown. SF1126 induced cell cycle arrest at the G1 phase with reduced S phase (proliferating fraction) in all cells.