Fig. 6

Detection of Top1-DNA cleavage complexes following drug treatment of parental or SN-38 resistant cells. Cells were exposed to drug for 1 h, either a SN-38 (10, 1 or 0.1 μM) or b NSC 743400/LMP400 (1 μM). Formed cleavage complexes were measured by alkaline elution and are given as DNA crosslinks (in rad-equivalent). Shown are mean values ± standard deviations of four replicates. P-values were calculated between corresponding parental and resistant cell lines treated with 1 μM of either SN-38 or NSC 743400