Fig. 5

Apoptosis is induced after G₂ arrest. A Western blot. Cells were treated by 100 nM CBG for the indicated times. Levels of activated caspase 3 were markedly increased after treatment by 100 nM CBG for 24 h. B, C Flow cytometry analysis of apoptosis. Cells were treated by 100 nM CBG for the indicated times. The number of Annexin V-positive cells increased dramatically after 24 h of treatment by 100 nM CBG. The pan-caspase inhibitor Z-VAD-FMK blocked the increase in Annexin V-positive cells. D TUNEL assay. SW480 cancer cells were treated by the indicated doses of CBG for 24 h. Apoptotic cells were labeled by FITC-conjugated dUTP. CBG treatment dose-dependently increased the degree of apoptosis (scale bar: 50 μm). E Measurement of mitochondrial membrane potential. SW480 cancer cells were treated by the indicated doses of CBG for 24 h and stained with JC-1. The mitochondrial membrane potential probe JC-1 forms aggregate in the mitochondria of healthy cells and emits red fluorescence. Loss of mitochondrial membrane potential causes JC-1 to disperse into monomers and emits green fluorescence. CBG treatment dose-dependently increased the intensity of green fluorescence, while the intensity of red fluorescence decreased (scale bar: 25 μm). n.s.:  not significant, ***: p < 0.001, ****: p < 0.0001 vs vehicle control (n = 3)