Fig. 9. Stachybochartins C (3) and G (7) induced caspase-dependent apoptosis in U-2OS cells. (A) U-2OS cells were pretreated with 3 (0–15 μM) or 7 (0–8 μM) for 48 h and apoptosis rates were analyzed via flow cytometry. (B) After treatment with 7 (0–8 μM) and DOX (1 μM, as a positive control) for 48 h, the expression levels of PARP and cleaved PARP, pro-caspase-8, cleaved caspase-8, pro-caspase-9, and cleaved caspase-9, were analyzed via western blotting. β-Actin was used as a protein loading control. The data are presented as mean ± SEM from three independent experiments. *: P < 0.05 and **: P < 0.01, compared to the control.