Figure 1

ROS mediate cell death and growth arrest induced by celastrol. H1299 and HepG2 cells were treated with the indicated concentration of celastrol (Cel) in the absence or presence of 5 mM NAC for 24 h. A. Celastrol induces dose-dependent ROS accumulation. Cells were stained with DCFH-DA and washed with PBS. More than three fields in each group were observed by fluorescence microscope (200×), and representative images are shown. B. ROS mediate the reduction of cell viability induced by celastrol. Viable cells were counted by trypan blue exclusion. Representative measurements of at least three independent experiments are shown. The values reported represent the mean ± SD of three separate experiments. *P < 0.01. C. ROS mediate G2-M phase blockage induced by celastrol. Cells were stained with PI and analyzed by flow cytometry. Representative measurements of at least three independent experiments are shown. The values reported represent the mean ± SD of three separate experiments. *P < 0.01 compared with control cells. D. ROS mediate apoptosis and necrosis induced by celastrol. Cells were stained with PI and annexin V-FITC and analyzed by flow cytometry. Representative measurements of at least three independent experiments are shown. The values of cell death (apoptosis and necrosis) reported represent the mean ± SD of three separate experiments. *P < 0.01 compared with control cells.