Figure 4.
Effects of inhibiting the MAPK signaling pathway on cell viability and apoptosis. (A) HepG2 and Huh7 cells were pretreated with PD98059 (20 µM), SP600125 (10 µM) and SB203580 (10 µM) for 24 h. The cell lysates were prepared for immunoblotting to examine the inactivation of the target pathways. (B) Measurements by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay of cell viability upon treatment with 100 µg/ml HP, with or without MAPK inhibitors for 24 h. The data are presented as the mean ± SEM from three independent experiments. *P<0.05 indicates a significant increase in cell viability following treatment with MAPK inhibitors. (C) Influence of the MAPK signaling pathway on apoptosis. Cell apoptosis was analyzed by flow cytometry upon treatment with 100 µg/ml HP, with or without MAPK inhibitors for 24 h. The statistical results are presented in a bar chart. The data correspond to the mean ± SEM from three independent experiments. *P<0.05 and **P<0.01 indicate a significant decrease in the apoptosis rate following treatment with MAPK inhibitors. UL, upper left; UR, upper right; LL, lower left; LR, lower right; PI, propidium iodide; HP, Huaier polysaccharide; p, phosphorylated; ERK, extracellular signal-regulated kinase; JNK, c-Jun N-terminal kinase; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; MAPK, mitogen-activated protein kinase; SEM, standard error of the mean.