GAA induces H2AX phosphorylation in a cell cycle-dependent manner in MEC-1 cells. (A) Bivariate (γH2AX IF vs DNA content) distributions of control and GAA-treated cells (GAA treated for 24 h). (B) The percentage of γH2AX positive cells in G1, S and G2/M cells after MEC-1 cells were treated with different doses of GAA for 24 h and 20 μ mol/l GAA treated for different time points (C). (D) Cell cycle distribution 24 h following GAA treatment. (E) Cell cycle distribution of MEC-1 cells after treatment with different doses GAA for 24 h (a: Control. b: 2.5 μ mol/l GAA. c: 5 μ mol/l GAA. d: 10 μ mol/l GAA. e: 20 μ mol/l GAA. f: 40 μ mol/l)and 20 μ mol/l GAA treated for different time points (F) n = 3, *: P < 0.05, **: P < 0.01 vs Control.