Figure 4
From: New Topoisomerase I mutations are associated with resistance to camptothecin
Assessment of DNA double strand break formation by measuring H2AX phosphorylation in SN38 sensitive and resistant HCT116 cells treated or not with SN38 (0.5 μM SN38 for 20 hours). A) Immunofluorescence: % indicates the number of cells with entirely stained nucleus. B) Fluorescence-activated cell sorting: % indicates the number of cells with fluorescence intensity >102. Data represent the mean ± SD of at least 3 independent experiments.