Estrogens metabolites in the release of inflammatory mediators from human amnion-derived cells

Aims: Human amnion-derived cells have been used as in vitro model to test the release of inflammatory mediators, such as arachidonic acid (AA) and prostaglandin E2 (PGE2). We compared estrogen metabolites for their ability to induce AA release, to influence PGE2 production and to interact toward intracellular estrogen receptors (ERs). Main methods: Metabolites effects on AA and PGE2 release were examined by radiolabelled substrate incorporation and by colorimetric enzyme immunoassays, respectively. [3H]17-beta-estradiol binding displacements were performed on Ro-20-1724 treated whole cells. Key findings: In WISH cells, estrone, 2-hydroxy-estrone and estriol induced a rapid dose dependent release of AA that was not inhibited by cycloheximide. Estrone and 2-hydroxy-estrone showed biphasic dose-response curves of PGE2, whereas estriol and 16-alpha-hydroxy-estrone increased PGE2 levels at high concentrations. 2-methoxy-estrone, 4-hydroxy-estradiol and 4-hydroxy-estrone did not significantly affected PGE2 release. 2-methoxy–estradiol and 2-hydroxy-estradiol decreased the PGE2 release. Effects of metabolites on PGE2 were inhibited by cycloheximide and by the ERs antagonist tamoxifen. In AV3 cells PGE2 production was poorly detectable. On Ro-20-1724 treated WISH cells the Ki of 17-beta-estradiol was 29.2 +/- 5.4 nM. Estrone, 2-methoxy-estrone and 2-methoxy-estradiol showed similar affinity values. The hydroxyl substituent at position 2, 4 and 16 decreased or a markedly increased the affinity for estradiol or estrone derivatives, respectively. Significance: The estrogen metabolites induced nongenomic effects on AA release from WISH cells. The influences on PGE2 release were detectable only on WISH cells. These effects appeared genomic and mediated by intracellular ERs, whose properties seemed strongly dependent on intracellular cAMP levels.