Figure 3

Bivariate distributions (DNA content vs. γH2AX) of OVISE and RMG-I cell lines, treated with CBDCA (Upper, OVISE; Lower, RMG-I). The dotted lines indicate control. Arrow heads and arrows indicate DNA damage and apoptosis, respectively. (A) Both cell lines treated with various concentrations of CBDCA for 24 h. DNA damage was observed in the S-phase cells at 1 μg/ml and 10 μg/ml concentrations in OVISE and RMG-1, respectively. DNA damage was found in both cell lines at every cell cycle as the concentration increased, and apoptosis occurred at a concentration of 50 μg/ml. More cells remained free of DNA damage in RMG-1 than in OVISE. (B) Both cell lines were treated with 1 μg/ml, the minimum concentration inducing DNA damage in either cell line, for various reaction times. In OVISE, S-phase cells with DNA damage progressed to apoptosis after 48 h. DNA damage was also found in G2/M-phase cells after 48 h, but most did not progress to apoptosis. S and G/2 M-phase arrests were observed. DNA damage was found in S and G2/M-phase cells after 48 h in RMG-I. The S-phase cells with DNA damage progressed to apoptosis 78 h later, but G2/M-phase cells showing DNA damage remained. S and G/2 M-phase arrests were observed.