High-Throughput Transcriptomics Toxicity Assessment of Eleven Data-Poor Bisphenol A Alternatives

Bisphenol A (BPA), a widely used chemical in the production of plastics and epoxy resins, has garnered significant attention due to its association with adverse health effects, particularly its endocrine-disrupting properties. Regulatory measures aimed at reducing human exposure to BPA have led to a proliferation of alternative chemicals used in various consumer products. While these alternatives serve to reduce BPA exposure, concerns have arisen regarding their safety and potential toxicity as regrettable substitutes. Previous efforts have demonstrated that in vitro high-throughput transcriptomics (HTTr) studies can be used to assess the endocrine-disrupting potential of BPA alternatives, and this strategy produces transcriptomic points-of-departure (tPoDs) that are protective of human health when compared to the PODs from traditional rodent studies. In this study, we leveraged in vitro HTTr advancements to assess the toxicity of eleven data-poor legacy chemicals sharing structural similarities to BPA. Human breast cancer MCF-7 cells were exposed to BPA and 11 alternatives at concentrations ranging from (0.1 - 25 µM) to assess toxicity. Analysis of global transcriptomic changes and a previously characterized estrogen receptor alpha (ERα) biomarker signature revealed that 9/11 chemicals were bioactive. One of the chemicals (2,4’-Bisphenol A) activated the ERα biomarker at the same concentration as BPA (i.e., 4,4’-BPA) but was deemed to be more potent as it induced global transcriptomic changes at lower concentrations. These results are addressing data gaps in ongoing screening assessments to identify BPA alternatives with hazard potential and are helping to identify potential candidates to serve as safer alternatives.