title: Rigorous 3-dimensional spectral data activity relationship approach modeling strategy for ToxCast estrogen receptor data classification, validation, and feature extraction.
abstract: The estrogenic potential (expressed as a score composite of 18 high throughput screening bioassays) of 1528 compounds from the ToxCast database was modeled by a 3-dimensional spectral data activity relationship approach (3D-SDAR). Due to a lack of17O nuclear magnetic resonance (NMR) simulation software, the most informative carbon-carbon 3D-SDAR fingerprints were augmented with indicator variables representing oxygen atoms from carbonyl and carboxamide, ester, sulfonyl, nitro, aliphatic hydroxyl, and phenolic hydroxyl groups. To evaluate the true predictive performance of the authors' model the United States Environmental Protection Agency provided them with a blind test set consisting of 2008 compounds. Of these, 543 had available literature data-their binding affinity served to estimate the external classification accuracy of the developed model: predictive accuracy of 0.62, sensitivity of 0.71, and specificity of 0.53 were obtained. Compared with alternative modeling techniques, the authors' model displayed very little reduction in performance between the modeling and the prediction set. A 3D-SDAR mapping technique allowed identification of structural features essential for estrogenicity: 1) the presence of a phenolic OH group or cyclohexenone, 2) a second aromatic or phenolic ring at a distance of 6 Å to 8 Å from the oxygen of the first phenol ring, 3) the presence of a methyl group approximately 6 Å away from the centroid of a phenol ring, and 4) a carbonyl group in close proximity (∼4 Å measured to the centroid) to 1 of the phenol rings. Environ Toxicol Chem 2017;36:823-830. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
authors: Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA.
authors: Svetoslav H
authors: SH
authors: Slavov
authors: Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA.
authors: Richard D
authors: RD
authors: Beger
mesh_terms: D052244:Endocrine Disruptors / Q000737:chemistry / Q000145:classification / Q000633:toxicity; D057166:High-Throughput Screening Assays; D009682:Magnetic Resonance Spectroscopy; D008962:Models, Theoretical; D011485:Protein Binding; D011960:Receptors, Estrogen / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D052244:Endocrine Disruptors; D011960:Receptors, Estrogen
keywords: 3D-Spectral Data-Activity Relationship; Classification model; Estrogen receptor; ToxCast database; Validation