Celecoxib influences steroid sulfonation catalyzed by human recombinant sulfotransferase 2A1

• Modulation of steroid sulfonation by celecoxib was investigated.
• In vitro and in silico approaches were used.
• Celecoxib inhibited DHEA and testosterone sulfonation with IC50 of 60–80 μM.
• Celecoxib greatly increased 17-sulfonation of 17-β-estradiol analogs.
• Modeling studies suggest celecoxib docks in the substrate-binding site of SULT2A1.

Celecoxib has been reported to switch the human SULT2A1-catalyzed sulfonation of 17β-estradiol (17β-E2) from the 3- to the 17-position. The effects of celecoxib on the sulfonation of selected steroids catalyzed by human SULT2A1 were assessed through in vitro and in silico studies. Celecoxib inhibited SULT2A1-catalyzed sulfonation of dehydroepiandrosterone (DHEA), androst-5-ene-3β, 17β-diol (AD), testosterone (T) and epitestosterone (Epi-T) in a concentration-dependent manner. Low μM concentrations of celecoxib strikingly enhanced the formation of the 17-sulfates of 6-dehydroestradiol (6D-E2), 17β-dihydroequilenin (17β-Eqn), 17β-dihydroequilin (17β-Eq), and 9-dehydroestradiol (9D-E2) as well as the overall rate of sulfonation. For 6D-E2, 9D-E2 and 17β-Eqn, celecoxib inhibited 3-sulfonation, however 3-sulfonation of 17β-Eq was stimulated at celecoxib concentrations below 40 μM. Ligand docking studies in silico suggest that celecoxib binds in the substrate-binding site of SULT2A1 in a manner that prohibits the usual binding of substrates but facilitates, for appropriately shaped substrates, a binding mode that favors 17-sulfonation.