Fig. 2

Gimatecan induces apoptosis in human GC cells. a, b Gimatecan, rather than irinotecan, significantly induced cell apoptosis in SNU-1 and NCI-N87 cells by flow cytometry assays. Cells were treated with gimatecan (0–1 µM) and irinotecan (0–1 µM) for 24 h and stained with Annexin V-PE/7-AAD. Sums of percentages of early apoptosis (Q3) and late apoptosis (Q2) were calculated as the total apoptosis ratios. c, d Pro- and anti-apoptotic proteins including Bcl-2, Bak, PARP and cleaved PARP were assessed by western-blotting in SNU-1 and NCI-N87 cells. Western-blotting bands were quantified and normalized by ImageJ. All data are mean ± SD of three independent experiments. *Compared with controls, *p < 0.05; ***p < 0.001; ****p < 0.0001