HSP90 Inhibitors, Geldanamycin and Radicicol, Enhance Fisetin-Induced Cytotoxicity via Induction of Apoptosis in Human Colonic Cancer Cells
Figure 3
Disruption of the mitochondrial membrane potential (MMP) by fisetin (FIS)+geldanamycin (GA) or FIS+radicicol (RAD) in COLO205 cells. (a) GA or RAD increased loss of the MMP by FIS in COLO205 cells. Cells were treated with GA (G; 2 μM) or RAD (R; 5 μM) with or without FIS (F; 60 μM) for 6 h, and the MMP was detected by a flow cytometric analysis using DiOC6 as a fluorescent dye. (Left panel) a representative of flow cytometric analysis. (Right panel) percentage of M1 was measured and expressed as the mean ± S.E. from three independent experiments. (b) GA or RAD induced cleavage of the caspase-9 protein in FIS-treated COLO205 cells. Cells were treated with GA, RAD, FIS+GA, or FIS+RAD for 24 h, and expression of caspase-9 (Casp 9) protein was detected by western blotting. (c) Increased caspase-9 activity by FIS+GA or FIS+RAD in COLO205 cells. The peptidyl caspase 9 substrate, Ac-YVAD-pNA, was used to detect caspase-9 activity in COLO205 cells under different treatments. Each data point was calculated from three triplicate groups, and data are displayed as the mean ± S.E. denotes a significant difference from the control (C) group.
