Science Inventory

How does stress modify chemical toxicity? A high-throughput in vitro screening approach

Citation:

Word, L., C. Willis, S. Padilla, C. Weitekamp, K. Carstens, L. Everett, B. Knapp, R. Judson, AND J. Harrill. How does stress modify chemical toxicity? A high-throughput in vitro screening approach. 12th World Congress on Alternatives and Animal Use in the Life Sciences, Niagara Falls, N/A, CANADA, August 27 - 31, 2023. https://doi.org/10.23645/epacomptox.24069429

Impact/Purpose:

Presentation to the 12th World Congress on Alternatives and Animal Use in the Life Sciences meeting August 2023. This work describes the method we are developing for screening how stress levels impact chemical toxicity. Cells are being exposed to cortisol and toxicants to determine whether the combination produces synergistic, additive, or antagonistic effects not predicted by chemical exposure alone.

Description:

Stress plus chemical exposure may produce effects not observed with chemical exposure alone. Therefore, there is a need for new approach methods that can rapidly screen chemicals for their interaction with stressed biological systems, which will advance understanding of inter- and intra- individual susceptibility risk determination. We are developing a method for this using in vitro chemical screening by phenotypic profiling of human osteosarcoma cells that express fluorescent nuclear and cytoskeletal fusion proteins (U-2 OS_FP). These cells have glucocorticoid receptor, which is the target of the stress hormone, cortisol. For control over cortisol dosing during the experiment, the cells were transitioned to a serum-free media. During this process, as serum and thus cortisol levels were decreased, cell responded to the change by having reductions in cell proliferation. Next, the U-2 OS_FP cells will be co-exposed to a mixture of cortisol and toxicants in a time-course dose-response screen to rapidly evaluate phenotypic changes in cell structure. We are screening 147 chemicals, including chemicals that are relevant to environmental justice (n=73), impact the glucocorticoid receptor (n=22) or overlapping gene pathways (n=25), are carcinogenic (n=20) or endocrine disruptors (n=15), and/or induce cell stress responses (n=13). These chemicals will each be evaluated for whether they have synergistic, additive, or antagonistic effects under conditions of low vs high stress (cortisol) levels. This research will improve human in vitro modeling of how stress comorbidity may impact adverse outcomes from chemical exposure. The views are the authors’ and do not necessarily represent the views of the U.S.EPA.