Integrated Network Toxicology, Molecular Dynamics Simulation and In Vitro Assays Identify EGFR, ESR1 and IGF1 as Core Mediators of Bisphenol S-Exacerbated Polycystic Ovary Syndrome

Bisphenol S (BPS), an environmental endocrine disruptor, has been implicated in polycystic ovary syndrome (PCOS), but its underlying molecular targets remain largely uncharacterized. Here, this study integrated network toxicology, molecular simulations and in vitro cellular assays to identify key mediators of BPS-associated PCOS. A total of 199 overlapping target genes between BPS exposure and PCOS were screened from public databases, predicted hub genes were extracted via protein–protein interaction (PPI) network construction and 30 core hub genes were enriched in oxidative stress, hormone response, inflammation, cell-cycle regulation, and PI3K-Akt, FoxO, AGE-RAGE, and endocrine resistance pathways by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Using molecular docking simulations found that the top 15 hub proteins exhibited favorable binding affinities for BPS, with binding free energies below −5.0 kcal/mol. Molecular dynamics simulations revealed that BPS binding induced only minor conformational perturbations in EGFR and ESR1, with negligible effects on backbone stability, core domain flexibility, global compactness and surface properties. In contrast, BPS association effectively dampened global backbone fluctuations and the residue-level mobility of IGF1, and the intermolecular hydrogen bond strength followed the order IGF1 > EGFR > ESR1. In KGN cells, BPS suppressed cell viability and proliferation in a time- and dose-dependent manner while upregulating the protein levels of EGFR, ESR1 and IGF1; notably, IGF1 was most sensitive to low-dose BPS exposure. These findings suggest that BPS may exacerbate PCOS progression by upregulating EGFR, ESR1 and IGF1 to inhibit granulosa cell growth, and thereby disrupt ovarian oxidative homeostasis, hormone signaling, insulin metabolism and cell-cycle regulation via the PI3K-Akt and FoxO pathways. This study provides a theoretical framework for assessing the reproductive health risks of BPS, and lays a foundation for further experimental validation and population-based epidemiological research.