title: 17-epiestriol, an estrogen metabolite, is more potent than estradiol in inhibiting vascular cell adhesion molecule 1 (VCAM-1) mRNA expression.
abstract: 17-beta estradiol (17-beta E(2)) attenuates the expression of vascular cell adhesion molecule 1 (VCAM-1) in vivo at physiological levels (pg/ml), whereas supraphysiological concentrations of 17-beta E(2) (ng/ml) are required in vitro. We assessed whether a metabolite of estrogen, which could only be generated in vivo, might be a more potent inhibitor of VCAM-1 expression and thereby explain this discrepancy. We report here that 17-epiestriol, an estrogen metabolite and a selective estrogen receptor (ER) beta agonist, is approximately 400x more potent than 17-beta E(2) in suppressing tumor necrosis factor (TNF) alpha-induced VCAM-1 mRNA as well as protein expression in human umbilical vein endothelial cells. Genistein, an ERbeta agonist, at low concentrations (1 and 10 nm) also suppressed TNFalpha-induced VCAM-1 mRNA expression. These actions of 17-epiestriol and genistein were significantly attenuated in the presence of the estrogen receptor antagonist ICI-182780. Other estrogenic compounds such as ethinyl estradiol and estrone did not have any effect on TNFalpha-induced VCAM-1 expression at the concentrations tested. We further show that, 1) 17-epiestriol induces the expression of endothelial nitric-oxide synthase mRNA and protein, 2) 17-epiestriol prevents TNFalpha-induced migration of NFkappaB into the nucleus, 3) N(G)-nitro-l-arginine methyl ester, an inhibitor of NO synthesis, abolishes 17-epiestriol-mediated inhibition of TNFalpha-induced VCAM-1 expression and migration of NFkappaB from the cytoplasm to the nucleus. Our results indicate that 17-epiestriol is more potent than 17-beta E(2) in suppressing TNFalpha-induced VCAM-1 expression and that this action is modulated at least in part through NO.
authors.affiliation: Department of Obstetrics and Gynecology, University of California, Los Angeles, California 90095-1740, USA.
authors.forename: Tapan K
authors.initials: TK
authors.lastname: Mukherjee
authors.forename: Lauren
authors.initials: L
authors.lastname: Nathan
authors.forename: Hillary
authors.initials: H
authors.lastname: Dinh
authors.forename: Srinivasa T
authors.initials: ST
authors.lastname: Reddy
authors.forename: Gautam
authors.initials: G
authors.lastname: Chaudhuri
mesh_terms: D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D004958:Estradiol / Q000737:chemistry / Q000494:pharmacology*; D004964:Estriol / Q000737:chemistry / Q000494:pharmacology*; D004967:Estrogens / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000819:agonists; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics*
chemical_list: D004967:Estrogens; D016328:NF-kappa B; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D009569:Nitric Oxide; D004958:Estradiol; D004964:Estriol