Figure 10
OA inhibits TNFα-induced PP2A phosphatase activity and increases TNFα-induced IL-6 and IL-8 mRNA expression and protein secretion.
(A) PP2A enzymatic activity was measured in A549 cells treated for 45 min with vehicle or 1 μM OA. Cells were washed before stimulation with TNFα (4 ng/ml) and then PP2A enzymatic activity (measured as pmol free phosphate) was detected at 1 h. Statistical analysis was performed using one-way ANOVA then Bonferroni’s post-test (where § denotes a significant effect of OA on on TNFα-induced effects). (B-E) A549 cells were treated for 45 min with vehicle or 1 μM OA. Cells were washed before stimulation with TNFα (4 ng/ml). (B) IL-6 and (C) IL-8 mRNA expression was measured at 0, 1, 2, 4, 8 and 24 h (results expressed as fold increase compared to vehicle-treated cells at 0 h) and (D) IL-6 and (E) IL-8 protein secretion measured at 24 h. Statistical analysis was performed using two-way ANOVA then Bonferroni’s post-test (where §denotes a significant effect of OA on TNFα-induced effects (P < 0.05)). Data are mean ± SEM values from n = 3 independent experiments.
