ICCVAM Biennial Report 2014-2015

ICCVAM Biennial Report 2014-2015

Endocrine Disruptor Testing: NIEHS and EPA Activities

Development of Domain-specific QSAR Models for Estrogenic Activity

NICEATM (National Institute of Environmental Health Sciences) is working with scientists at the U.S. Environmental Protection Agency (EPA) and the University of North Carolina at Chapel Hill to develop domain-specific quantitative structure-activity relationship (QSAR) models using data from Tox21 and ToxCast assays. For example, the team developed QSAR models to predict specific activity and relative potency of phenolic compounds that act on the estrogen pathway. The domain-specific models consistently yielded higher balanced accuracy, sensitivity, and specificity than models that considered all possible chemical structures. Posters describing these models were presented at the 2015 American Society for Cellular and Computational Toxicology (ASCCT) Annual Meeting (Mansouri et al.) and the 2015 Society of Toxicology (SOT) FutureTox III meeting (Mansouri et al.).

Computational Model for Prediction of Androgenic Activity

Data from nine Tox21 and ToxCast assays were integrated into a computational model that predicts androgen receptor (AR) agonist and antagonist bioactivity. The preliminary results from this model were presented at the December 2014 meeting of the EPA Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel. The model is currently undergoing refinement.

QSAR Model to Predict Androgen Receptor Binding Activity

Using data from nine Tox21 and ToxCast assays, NICEATM is developing a QSAR model to predict AR binding activity, with the goal of using the model to predict AR pathway activity for chemicals being evaluated in the EPA Endocrine Disruptor Screening Program. Posters describing the model were presented at the 2015 SOT Annual Meeting (Zang et al.), 2015 ASCCT Annual Meeting (Zang et al.) and 2015 SOT FutureTox III meeting (Zang et al.).