Effect of Prunetin on TNF-α-Induced MUC5AC Mucin Gene Expression, Production, Degradation of IκB and Translocation of NF-κB p65 in Human Airway Epithelial Cells

BACKGROUND We investigated whether prunetin significantly affects tumor necrosis factor-α (TNF-α)-induced MUC5AC mucin gene expression, production, inhibitory kappa B (IκB) degradation and nuclear factor kappa B (NF-κB) p65 translocation in human airway epithelial cells. METHODS Confluent NCI-H292 cells were pretreated with prunetin for 30 minutes and then stimulated with TNF-α for 24 hours or the indicated periods. MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The effect of prunetin on TNF-α-induced degradation of IκB and translocation of NF-κB p65 was investigated by western blot analysis. RESULTS We found that incubation of NCI-H292 cells with prunetin significantly inhibited mucin production and down-regulated the MUC5AC gene expression induced by TNF-α. Prunetin inhibited TNF-α-induced degradation of IκB and translocation of NF-κB p65. CONCLUSION This result suggests that prunetin inhibits the NF-κB signaling pathway, which may explain its role in the inhibition of MUC5AC mucin gene expression and production regulated by the NF-κB signaling pathway.