Cyathin-R induces apoptosis in Bax−/− HCT116 cells.
A and B, Bax−/− HCT116 cells were treated with the indicated concentrations of cyathin-R for 24 h, harvested, and divided into two parts. One part was stained with annexin-V/PI and the other with a CaspACE-FITC-conjugated caspase marker. Both populations were analyzed by flow cytometry. Data from one of the three independent experiments are shown on the left. Means ± S.E. (error bars) (n = 3) are presented. C, Bax−/− HCT116 cells were pretreated with Z-VAD-fmk caspase inhibitor for 1 h at the indicated concentrations, followed by a 24-h incubation with cyathin-R. Cells were stained with annexin-V-FITC and PI and analyzed by flow cytometry. Means ± S.E. (n = 3) are reported. D, effect of cyathin-R on mitochondria membrane potential. Bax−/− HCT116 cells were treated with the indicated concentrations of cyathin-R (6 h). After staining with TMRM for 10 min at 37 °C, cells were analyzed by flow cytometry. Means ± S.E. (n = 3) are reported. FCCP, carbonyl cyanide p-trifluoromethoxyphenylhydrazone. **, p < 0.01; ***, p < 0.001.