Assessing the toxicological effects of exposure to polyethylene terephthalate on hepatocellular carcinoma: insights from network toxicology, molecular docking, molecular dynamics, and experimental validation.

Background: Polyethylene terephthalate (PET), one of the most widely used synthetic polymers globally, has emerged as a potential environmental risk factor for human health. However, the molecular mechanisms linking PET exposure to hepatocellular carcinoma (HCC) remain poorly understood. Methods: We adopted an integrated systems biology framework that combined computational target prediction (using ChEMBL, PharmMapper, and SwissTargetPrediction), transcriptomic profiling, and machine learning to elucidate key molecular targets and pathways involved in PET-associated hepatocarcinogenesis. Immune cell infiltration was assessed via CIBERSORT. Molecular docking followed by 100 ns molecular dynamics simulations were employed to verify protein-ligand binding interactions. The expression profiles and prognostic relevance of core genes were evaluated using TCGA-LIHC datasets. Results: We identified 235 potential PET-interacting proteins, with 40 genes overlapping with HCC-associated genes. Integrated analysis consistently identified PLK1, CCNA2, and CDC25C as core mediators of PET-associated hepatocarcinogenesis. Molecular docking revealed potential binding interactions, with PLK1 showing the highest affinity (--8.0 kcal/mol). Molecular dynamics simulations confirmed sustained structural stability of these PET-protein complexes over 100 ns. Clinical data analysis demonstrated progressive upregulation of these genes with advancing tumor stage and grade, with high expression predicting poor overall survival. PET treatment of Hep3B and HepG2 cells significantly upregulated PLK1, CCNA2, and CDC25C expression at both mRNA and protein levels, enhanced colony formation capacity, increased EdU-positive cells, and promoted G2/M phase progression. Western blotting further revealed upregulation of the proliferation marker PCNA. Functional enrichment analysis revealed involvement of cell cycle regulation, metabolic reprogramming, and immune microenvironment remodeling. CIBERSORT analysis identified significant correlations between core gene expression and infiltration of neutrophils, monocytes, and macrophages, alongside negative associations with lymphoid populations. Conclusion: PET exposure may promote hepatocarcinogenesis through multi-layered mechanisms involving cell cycle dysregulation (primarily via PLK1, CCNA2, and CDC25C), metabolic reprogramming, and immune microenvironment remodeling. These findings provide mechanistic insights into plastic-associated cancer risk and identify potential biomarkers and therapeutic targets for populations with PET exposure.