Figure 2

ROS mediate the decrease of HSP90 client proteins induced by celastrol. A. ROS mediate the decrease of HSP90 client proteins induced by celastrol. H1299 and HepG2 cells were treated with the indicated concentrations of celastrol in the absence or presence of 5 mM NAC for 24 h. The alteration of PARP, EGFR, AKT, CDK4 and actin was analyzed by western blotting. B. Celastrol-induced decrease of HSP90 client proteins is independent of apoptosis. H1299 cells were treated with or without 4 μM celastrol in the absence or presence of 50 μM Z-VAD for 24 h. The alteration of PARP, EGFR, Akt, CDK4 and actin was analyzed by western blotting. C. Celastrol does not disrupt the interaction between HSP90 and Cdc37 in H1299 cells. H1299 cells were treated with or without 6 μM celastrol for 12 h in the absence and presence of 5 mM NAC. Cell lysate was immunoprecipitated with an HSP90 antibody. Western blotting was used to detect HSP90 and Cdc37. D. NAC does not inhibit the degradation of EGFR and AKT induced by 17-AAG. H1299 cells were treated with or without 5 μM 17-AAG and 6 μM celastrol for 24 h in the absence and presence of 5 mM NAC. The alteration of EGFR, AKT and actin was analyzed by western blotting. All of the above experiments were repeated multiple times, and similar results were obtained each time; therefore, representative images are shown.