Inhibition of airway MUC5AC mucin production and gene expression induced by epidermal growth factor or phorbol ester by glycyrrhizin and carbenoxolone

Background and aimIn this study, we investigated whether glycyrrhizin and carbenoxolone affect MUC5AC mucin production and gene expression induced by epidermal growth factor (EGF) or phorbol ester (PMA) from human airway epithelial cells.MethodsConfluent NCI-H292 cells were pretreated with each agent for 30 min and then stimulated with EGF and PMA for 24 h, respectively. MUC5AC mucin gene expression and mucin protein production were measured by RT-PCR and ELISA.ResultsGlycyrrhizin and carbenoxolone were found to inhibit the production of MUC5AC mucin protein induced by EGF or PMA, and both compounds also inhibited the expression of MUC5AC mucin gene induced by EGF or PMA.ConclusionThese results suggest that glycyrrhizin and carbenoxolone can inhibit mucin gene expression and production of mucin protein, by directly acting on airway epithelial cells.