Induction of drug-metabolizing enzymes and transporters in human bronchial epithelial cells by beclomethasone dipropionate

Inhaled steroids are the most potent anti-inflammatory therapy commonly used in bronchial asthma. There are, however, a small number of asthmatic patients who do not respond to inhaled steroid-treatment. The stimulation of metabolism and excretion of inhaled drugs at bronchial tissues might lead to a decrease in the effect of the drugs, although the molecular mechanism of this resistance is unclear. In this study, we found that beclomethasone dipropionate (BDP) stimulated the expression of mRNAs for uridine 5'-diphosphate glucuronosyl transferase 2B4 and 2B11, and transporters such as multidrug resistance P-glycoprotein, multidrug resistance-associated protein 1 and 2 in cultured bronchial epithelial cells. It is possible that the individual differences of expression of drug metabolizing enzymes and transporters and their enhancement with BDP are implicated in the individual differences of reactivity over steroid medical treatment.