Celecoxib influences steroid sulfonation catalyzed by human recombinant sulfotransferase 2A1

Abstract

Celecoxib has been reported to switch the human SULT2A1-catalyzed sulfonation of 17βestradiol (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.

Celecoxib affects estrogen sulfonation catalyzed by several human hepatic sulfotransferases, but does not stimulate 17-sulfonation in rat liver

“…Human recombinant SULT1A1*1, 1A3, 1B1, 1E1 and 2A1 were prepared and isolated as described previously [8, 18]. Assay conditions with all substrates were optimized such that the rate of reaction was linear with protein and time, and was saturating for PAPS.…”

“…The assay conditions with the steroid substrates were as described previously for SULT2A1 [18] except that 0.01–0.15 mg pooled human liver cytosol was used for 0.4 μM DHEA, AD, Epi-T, T, 17β-E2, 17α-E2, 3Me-E2, 6D-E2, 9D-E2, 17β-Eqn and 17β-Eq and 0.005–0.1 mg cytosol from rat livers was used for in vitro rat experiments. The reaction products of steroid sulfonation were analyzed by HPLC and LC-MS/MS as described previously [18].…”

“…The reaction products of steroid sulfonation were analyzed by HPLC and LC-MS/MS as described previously [18]. …”

“…The effects of celecoxib on the position and rate of sulfonation of several steroids, shown in Figure 1, have been examined with human recombinant SULT2A1 [18]. They are dehydroepiandrosterone (DHEA; (3β)-3-hydroxyandrost-5-en-17-one), androstenediol (AD; (3β,17β)-androst-5-en-3,17-diol), epitestosterone (Epi-T; (17α)-17-hydroxyandrost-4-en-3-one), testosterone (T; (17β)-17-hydroxyandrost-4-en-3-one), 17α-estradiol (17α-E2; (17α)-estra-1,3,5(10)-triene-3,17-diol), estrone (E1; 3-hydroxyestra-1(10),2,4-trien-17-one), 3-methyl ether of 17β-E2 (3Me-E2), 6-dehydroestradiol (6D-E2; estra-1,3,5(10),6-tetraene-3,17-diol), 17β-dihydroequilenin (17β-Eqn; 1,3,5(10)6,8-estrapentaen-3,17 β-diol),17β-dihydroequilin (17β-Eq; 1,3,5(10)7-estratetraen-3, 17β-diol) and 9-dehydroestradiol (9D-E2; (17β)-estra-1,3,5(10),9(11)-tetraene-3,17-diol).…”

“…Considering that rat liver is sexually dimorphic for the expression of sulfotransferases [26, 27], both female and male rat liver cytosolic preparations were tested separately for their activity towards steroid substrates in the presence and absence of celecoxib. For the species comparison, we selected substrates that showed isomer-selective differences of sulfonation catalyzed by SULT2A1 [18]. These were T and Epi-T, 17β-E2 and 17α-E2.…”