title: A 155-plex high-throughput in vitro coregulator binding assay for (anti-)estrogenicity testing evaluated with 23 reference compounds.
abstract: To further develop an integrated in vitro testing strategy for replacement of in vivo tests for (anti-)estrogenicity testing, the ligand-modulated interaction of coregulators with estrogen receptor α was assessed using a PamChip® plate. The relative estrogenic potencies determined, based on ERα binding to coregulator peptides in the presence of ligands on the PamChip® plate, were compared to the relative estrogenic potencies as determined in the in vivo uterotrophic assay. The results show that the estrogenic potencies predicted by the 57 coactivators on the peptide microarray for 18 compounds that display a clear E2 dose-dependent response (goodness of fit of a logistic dose-response model of 0.90 or higher) correlated very well with their in vivo potencies in the uterotrophic assay, i.e., coefficient of determination values for 30 coactivators higher than or equal to 0.85. Moreover, this coregulator binding assay is able to distinguish ER agonists from ER antagonists: profiles of selective estrogen receptor modulators, such as tamoxifen, were distinct from those of pure ER agonists, such as dienestrol. Combination of this coregulator binding assay with other types of in vitro assays, e.g., reporter gene assays and the H295R steroidogenesis assay, will frame an in vitro test panel for screening and prioritization of chemicals, thereby contributing to the reduction and ultimately the replacement of animal testing for (anti-)estrogenic effects.
authors.affiliation: Division of Toxicology, Wageningen University and Research Centre, Wageningen, The Netherlands. si.wang@wur.nl
authors.forename: Si
authors.initials: S
authors.lastname: Wang
authors.forename: René
authors.initials: R
authors.lastname: Houtman
authors.forename: Diana
authors.initials: D
authors.lastname: Melchers
authors.forename: Jac
authors.initials: J
authors.lastname: Aarts
authors.forename: Ad
authors.initials: A
authors.lastname: Peijnenburg
authors.forename: Rinie
authors.initials: R
authors.lastname: van Beuningen
authors.forename: Ivonne
authors.initials: I
authors.lastname: Rietjens
authors.forename: Toine F
authors.initials: TF
authors.lastname: Bovee
mesh_terms: D052244:Endocrine Disruptors / Q000737:chemistry / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000737:chemistry / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000819:agonists* / Q000378:metabolism*; D004967:Estrogens / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D046208:Microchip Analytical Procedures / Q000379:methods*; D040081:Protein Array Analysis / Q000379:methods*; D011485:Protein Binding; D015203:Reproducibility of Results
chemical_list: C506487:ESR1 protein, human; D052244:Endocrine Disruptors; D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D004967:Estrogens