Role of mitogen-activated protein kinase (MAPKs) in pterostilbene (PTER)-induced activation of caspases-8,-9, and -3.

<p>(A–C, upper panel) Phosphorylation levels of extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun N-terminal kinase (JNK)1/2 were assessed by a Western blot analysis after treatment with various concentrations of PTER (0∼150 µM M) for 24 h. (A–C, lower panel) Quantitative results of phopho-ERK1/2, p38, and JNK1/2 protein levels, which were adjusted with the total ERK1/2, p38, and JNK1/2 protein levels and expressed as multiples of induction beyond each respective control. Values represent the mean ± SE of three independent experiments. *<i>p</i><0.05, compared to the vehicle control group. (D, upper panel) HL-60 cells were pretreated with or without 20 µM U0126, SP600125, or SB202190 for 1 h followed by PTER (100 µM) treatment for an additional 24 h. Expression levels of cleaved caspase-3, -8, and -9 were determined by a Western blot analysis. (D, lower panel) Quantitative results of cleaved caspase-3, -8, and -9 protein levels, which were adjusted to the α-tubulin protein level and expressed as multiples of induction beyond each respective control. Values represent the mean ± SE of three independent experiments. Data were analyzed using a one-way ANOVA with Tukey’s post-hoc tests at 95% confidence intervals; different letters represent different levels of significance. Different letters represent significantly different, <i>p</i><0.05.