Chronic Monobutyl Phthalate Exposure Promotes Anaplastic Thyroid Cancer Progression Through Inflammatory Signaling Dysregulation: Integrated Transcriptomic and Network Toxicology Analyses

Background/Objectives: Chronic exposure to endocrine-disrupting chemicals has been increasingly recognized as a potential contributor to cancer progression. Monobutyl phthalate (MBP), a major metabolite of dibutyl phthalate, is widely detected in human biological samples, yet its long-term impact on anaplastic thyroid cancer (ATC) has not been systematically investigated. Methods: CAL-62 cells were continuously exposed to an environmentally relevant concentration of MBP (10 nM) over 3 months to establish a chronic exposure model that mimics long-term environmental exposure. Transcriptomic profiling was integrated with network toxicology to identify key molecular pathways and hub genes, followed by molecular docking and Western blot validation. Results: Chronic MBP exposure significantly enhanced cell viability, proliferation, colony formation, and tumorsphere formation, indicating promotion of malignant phenotypes. Transcriptomic profiling revealed extensive molecular remodeling characterized by activation of inflammation-associated pathways, including cytokine–cytokine receptor interaction, IL-17, TNF, and JAK–STAT signaling, accompanied by suppression of p53- and mTOR-related pathways. Integrated analysis identified 57 overlapping KEGG pathways, with IL6 and CSF2 emerging as central hub genes. Molecular docking demonstrated favorable binding affinities between MBP and representative target proteins, including IL6, TP53, CASP3, BCL2, and PPARG. Western blot analysis further confirmed increased IL6 and BCL2 expression together with decreased TP53, CASP3, and PPARG expression following chronic MBP exposure. Conclusions: Chronic environmentally relevant MBP exposure promotes ATC malignant progression through coordinated inflammation-associated molecular network remodeling accompanied by suppression of apoptosis-related signaling. Integrating network toxicology with transcriptomic profiling provides an effective systems-level strategy for identifying biologically relevant molecular networks underlying chronic environmental toxicant exposure.