Diethyl Phthalate (DEP) as a potential osteosarcoma risk factor: a multi-omics study integrating network Toxicology, single-cell RNA sequencing, and molecular docking.

Diethyl phthalate (DEP), a common plasticiser and endocrine disruptor, has been linked to cancer, but its role in osteosarcoma (OS) remains unclear. This study integrated network toxicology, transcriptomics, protein-protein interaction (PPI) analysis, machine learning, molecular docking, molecular dynamics (MD), single-cell RNA sequencing (scRNA-seq), and external validation to investigate DEP-related mechanisms in OS. We identified 45 DEP-responsive genes enriched in extracellular matrix-related pathways. PPI network analysis revealed 11 hub genes, of which LASSO, SVM-RFE, and Boruta algorithms consistently prioritised P4HA2, COL18A1, and COL10A1. Docking and MD simulations supported stable binding of DEP to P4HA2 and COL18A1 via hydrogen bonds and hydrophobic interactions. scRNA-seq demonstrated celltype-specific expression of these genes. Validation cohorts confirmed their upregulation in OS, with AUC values up to 0.950. These findings suggest that DEP may promote OS progression by targeting extracellular matrix remodelling, offering new diagnostic biomarkers and hypothesis-generating evidence for environmental osteocarcinogenesis.