Exploring Methyl-4-hydroxybenzoate-associated CDK1 dysregulation in breast cancer: A multi-omics investigation combining network toxicology, transcriptomics, and molecular dynamics.

Breast cancer remains a major global health burden, and environmental endocrine-disrupting chemicals may contribute to breast-cancer-related phenotypes. Methyl-4-hydroxybenzoate (MEP; methylparaben) is a widely used preservative with reported weak estrogenic activity, but its molecular association with breast cancer remains incompletely defined. In this study, we used an integrative exploratory framework combining target prediction, breast-cancer expression datasets, protein-protein interaction analysis, functional enrichment, single-cell transcriptomic signature analysis, molecular docking, molecular dynamics simulation, and in vitro assays. Target prediction identified 1067 putative MEP-associated candidates. Integration with breast-cancer-associated gene sets and GEO-derived differentially expressed genes yielded 29 shared genes, from which EGFR, TYMS, EZH2, CDK1, and BIRC5 emerged as highly connected network nodes. Enrichment analyses implicated cell-cycle-related and cancer-associated pathways. Single-cell analyses were revised to describe MEP-target-signature-high and MEP-target-signature-low cell groups rather than direct measurement of MEP as a transcript. Docking and molecular dynamics analyses suggested potential binding and structural stability for selected MEP-protein complexes; however, these computational data were interpreted as evidence of putative association rather than direct kinase activation. In vitro assays and transcriptomic profiling suggested that MEP exposure was associated with altered proliferation-related phenotypes and cell-cycle transcriptional programs. Overall, the findings support a hypothesis-generating model in which MEP is associated with breast-cancer-relevant transcriptional and signaling alterations, while further direct mechanistic validation, including CDK1 activity, loss-of-function, rescue, and in vivo studies, is required.