title: Extending an in vitro panel for estrogenicity testing: the added value of bioassays for measuring antiandrogenic activities and effects on steroidogenesis.
abstract: In the present study, a previously established integrated testing strategy (ITS) for in vitro estrogenicity testing was extended with additional in vitro assays in order to broaden its sensitivity to different modes of action resulting in apparent estrogenicity, i.e., other than estrogen receptor (ER) binding. To this end, an extra set of 10 estrogenic compounds with modes of action in part different from ER binding, were tested in the previously defined ITS, consisting of a yeast estrogen reporter gene assay, an U2OS ERα CALUX reporter gene assay and a cell-free coregulator binding assay. Two androgen reporter gene assays and the enhanced H295R steroidogenesis assay were added to that previous defined ITS. These assays had added value, as several estrogenic model compounds also elicited clear and potent antiandrogenic properties and in addition also showed effects on steroidogenesis that might potentiate their apparent estrogenic effects in vivo. Adding these assays, examining mechanisms of action for estrogenicity apart from ERα binding, gives a more complete and comprehensive assessment of the ability of test compounds to interfere with endocrine signaling. It was concluded that the extended ITS will go beyond in vivo estrogenicity testing by the uterotrophic assay, thereby contributing to the 3R-principles.
authors.affiliation: Division of Toxicology, Wageningen University and Research Centre, Tuinlaan 5, 6703 HE Wageningen, The Netherlands Business Unit of Toxicology & Bioassays, RIKILT - Institute of Food Safety, Wageningen University and Research Centre, Akkermaalsbos 2, 6708 WB Wageningen, The Netherlands.
authors.forename: Si
authors.initials: S
authors.lastname: Wang
authors.affiliation: Business Unit of Toxicology & Bioassays, RIKILT - Institute of Food Safety, Wageningen University and Research Centre, Akkermaalsbos 2, 6708 WB Wageningen, The Netherlands.
authors.forename: Jeroen C W
authors.initials: JC
authors.lastname: Rijk
authors.affiliation: BioDetection Systems B.V., Science Park 406, 1098 XH Amsterdam, The Netherlands.
authors.forename: Harrie T
authors.initials: HT
authors.lastname: Besselink
authors.affiliation: PamGene International B.V., Wolvenhoek 10, 5211 HH 's-Hertogenbosch, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: Houtman
authors.affiliation: Business Unit of Toxicology & Bioassays, RIKILT - Institute of Food Safety, Wageningen University and Research Centre, Akkermaalsbos 2, 6708 WB Wageningen, The Netherlands.
authors.forename: Ad A C M
authors.initials: AA
authors.lastname: Peijnenburg
authors.affiliation: BioDetection Systems B.V., Science Park 406, 1098 XH Amsterdam, The Netherlands.
authors.forename: Abraham
authors.initials: A
authors.lastname: Brouwer
authors.affiliation: Division of Toxicology, Wageningen University and Research Centre, Tuinlaan 5, 6703 HE Wageningen, The Netherlands.
authors.forename: Ivonne M C M
authors.initials: IM
authors.lastname: Rietjens
authors.affiliation: Business Unit of Toxicology & Bioassays, RIKILT - Institute of Food Safety, Wageningen University and Research Centre, Akkermaalsbos 2, 6708 WB Wageningen, The Netherlands.
authors.forename: Toine F H
authors.initials: TF
authors.lastname: Bovee
mesh_terms: D059002:Androgen Receptor Antagonists / Q000737:chemistry / Q000494:pharmacology*; D001681:Biological Assay / Q000379:methods*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000737:chemistry / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000737:chemistry / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D057166:High-Throughput Screening Assays / Q000379:methods; D006801:Humans; D008024:Ligands; D040081:Protein Array Analysis / Q000379:methods; D011485:Protein Binding; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism*; D012680:Sensitivity and Specificity
chemical_list: D059002:Androgen Receptor Antagonists; C506487:ESR1 protein, human; D052244:Endocrine Disruptors; D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D008024:Ligands; D011944:Receptors, Androgen
keywords: CALUX bioassay; H295R steroidogenesis assay; MARCoNI; coregulators; estrogenicity; high-throughput in vitro methods; yeast bioassay