Regulatory effects of 7,4′-dihydroxyflavone (7,4′-DHF) on phorbol 12-myristate 13-acetate (PMA)-stimulated phosphorylated IκBα (p-IκBα), phosphorylated NFκB (p-NF-κB), phosphorylated signal transducer and activator of transcription 6 (p-STAT6), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), and histone deacetylase 2 (HDAC2) expression. Serum-deprived NCI-H292 cells were pretreated with 7,4′-DHF (0, 2, and 10 µM) for 24 h followed by PMA (10 ng/mL) stimulation for 30 min. (A) The expression of p-IκBα, IκBα, p-NF-κB (p-p65), NF-κB(p65), p-STAT6, STAT6, p-ERK1/2, ERK1/2, HDAC2, and GAPDH (loading control) in whole cell extracts was evaluated by western blot analysis. Quantitative western blot analysis of p-IκBα (B), p-NF-κB (p-p65, C), p-STAT6 (D), and HDAC2 (E) expression was measured in three independent experiments. Densitometry of band intensity was expressed relative to that of non-stimulation, nontreatment control set at 100%. Phosphorylation status was present as the ratio between phosphorylated and total protein.* p < 0.05 ** p < 0.01, versus PMA stimulation alone group; # p < 0.05 ## p < 0.01, versus medium alone group.