Effect of squalene on G2/M checkpoint activity.

G2/M checkpoint analysis was performed by flow cytometry. (A) The percentage of mitotic cells was estimated according to the phosphorylation of histone H3 in Ser10-positive cells. A549 adenocarcinoma cells were counterstained with PI for visualization of DNA content. The cells were treated with 100 μM squalene for 4 h before and 1 h after γIR (0 and 6 Gy). (B) Data are expressed as the percentage of mitotic cells in the total number of cells. Data are presented as the mean ± S.D. of three independent experiments (*P < 0.05 vs. untreated control).