title: Editor's Highlight: Development of an In vitro Assay Measuring Uterine-Specific Estrogenic Responses for Use in Chemical Safety Assessment.
abstract: A toxicity pathway approach was taken to develop an in vitro assay using human uterine epithelial adenocarcinoma (Ishikawa) cells as a replacement for measuring an in vivo uterotrophic response to estrogens. The Ishikawa cell was determined to be fit for the purpose of recapitulating in vivo uterine response by verifying fidelity of the biological pathway components and the dose-response predictions to women of child-bearing age. Expression of the suite of estrogen receptors that control uterine proliferation (ERα66, ERα46, ERα36, ERβ, G-protein coupled estrogen receptor (GPER)) were confirmed across passages and treatment conditions. Phenotypic responses to ethinyl estradiol (EE) from transcriptional activation of ER-mediated genes, to ALP enzyme induction and cellular proliferation occurred at concentrations consistent with estrogenic activity in adult women (low picomolar). To confirm utility of this model to predict concentration-response for uterine proliferation with xenobiotics, we tested the concentration-response for compounds with known uterine estrogenic activity in humans and compared the results to assays from the ToxCast and Tox21 suite of estrogen assays. The Ishikawa proliferation assay was consistent with in vivo responses and was a more sensitive measure of uterine response. Because this assay was constructed by first mapping the key molecular events for cellular response, and then ensuring that the assay incorporated these events, the resulting cellular assay should be a reliable tool for identifying estrogenic compounds and may provide improved quantitation of chemical concentration response for in vitro-based safety assessments.
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.|ScitoVation, Research Triangle Park, North Carolina.
authors: Michelle M
authors: MM
authors: Miller
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.
authors: Rebecca A
authors: RA
authors: Alyea
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.
authors: Caroline
authors: C
authors: LeSommer
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.|ScitoVation, Research Triangle Park, North Carolina.
authors: Daniel L
authors: DL
authors: Doheny
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.|ScitoVation, Research Triangle Park, North Carolina.
authors: Sean M
authors: SM
authors: Rowley
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.
authors: Kristin M
authors: KM
authors: Childs
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.|ScitoVation, Research Triangle Park, North Carolina.
authors: Pergentino
authors: P
authors: Balbuena
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.|ScitoVation, Research Triangle Park, North Carolina.
authors: Susan M
authors: SM
authors: Ross
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.
authors: Jian
authors: J
authors: Dong
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.
authors: Bin
authors: B
authors: Sun
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.|ScitoVation, Research Triangle Park, North Carolina.
authors: Melvin A
authors: MA
authors: Andersen
authors: *The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina; rclewell@scitovation.com.|ScitoVation, Research Triangle Park, North Carolina.|*The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina.
authors: Rebecca A
authors: RA
authors: Clewell
mesh_terms: D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000187:drug effects*; D004967:Estrogens / Q000633:toxicity; D004997:Ethinyl Estradiol / Q000378:metabolism; D005260:Female; D006801:Humans; D011960:Receptors, Estrogen / Q000378:metabolism*; D014599:Uterus / Q000166:cytology / Q000187:drug effects*; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D004967:Estrogens; D011960:Receptors, Estrogen; D015262:Xenobiotics; D004997:Ethinyl Estradiol
keywords: TT21C; endocrine disruption; human health safety assessment; in vitro and alternative models.