Figure 5

Bivariate distributions (DNA content vs. γH2AX) of OVISE and RMG-I cell lines, treated with SN-38 (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 SN-38 for 24 h. Both cell lines exhibited DNA damage in S-phase cells at a minimum concentration of 0.5 ng/ml. (B) Both cell lines were treated with 0.5 ng/ml, the minimum concentration inducing DNA damage in either cell line, for various reaction times. S-phase cells with DNA damage started progressing to apoptosis after 72 and 96 h in OVISE and RMG-1, respectively. Both cell lines showed S-phase arrest, and large numbers of cells with DNA damage were still present even after 120 h.