GAA induced H2AX phosphorylation in a cell cycle-dependent manner in M059K and M059J cells. (A) (B) Bivariate(γH2AX IF vs DNA content) distributions of control and GAA-treated M059K and M059J cells (GAA treated for 24 h). (C) (D) The percentage of γH2AX positive cells in G1, S and G2/M cells after M059K and M059J cells were treated with different doses GAA for 24 h. (E) (F) Cell cycle distribution of M059K and M059J cells 24 h following GAA treatment. (G) (H) Cell cycle distribution of M059K and M059J cells after treatment with different doses of GAA for 24 h. (ACEG: M059K; BDFH: M059J. 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), n = 3, *: P < 0.05, **: P < 0.01 vs Control.