IUF - Leibniz-Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany.
King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal 23955-6900, Saudi Arabia.
Environ Int. 2022 Jan;158:106989. doi: 10.1016/j.envint.2021.106989. Epub 2021 Nov 20.
Polycyclic aromatic hydrocarbons (PAHs), dioxin-like compounds (DLCs) and structurally-related environmental pollutants may contribute to the pathogenesis of various diseases and disorders, primarily by activating the aryl hydrocarbon receptor (AHR) and modulating downstream cellular responses. Accordingly, AHR is considered an attractive molecular target for preventive and therapeutic measures. However, toxicological risk assessment of AHR-modulating compounds as well as drug development is complicated by the fact that different ligands elicit remarkably different AHR responses. By elucidating the differential effects of PAHs and DLCs on aldo-keto reductase 1C3 expression and associated prostaglandin D metabolism, we here provide evidence that the epidermal growth factor receptor (EGFR) substantially shapes AHR ligand-induced responses in human epithelial cells, i.e. primary and immortalized keratinocytes and breast cancer cells. Exposure to benzo[a]pyrene (B[a]P) and dioxin-like polychlorinated biphenyl (PCB) 126 resulted in a rapid c-Src-mediated phosphorylation of EGFR. Moreover, both AHR agonists stimulated protein kinase C activity and enhanced the ectodomain shedding of cell surface-bound EGFR ligands. However, only upon B[a]P treatment, this process resulted in an auto-/paracrine activation of EGFR and a subsequent induction of aldo-keto reductase 1C3 and 11-ketoreduction of prostaglandin D. Receptor binding and internalization assays, docking analyses and mutational amino acid exchange confirmed that DLCs, but not B[a]P, bind to the EGFR extracellular domain, thereby blocking EGFR activation by growth factors. Finally, nanopore long-read RNA-seq revealed hundreds of genes, whose expression is regulated by B[a]P, but not by PCB126, and sensitive towards pharmacological EGFR inhibition. Our data provide novel mechanistic insights into the ligand response of AHR signaling and identify EGFR as an effector of environmental chemicals.
多环芳烃(PAHs)、二恶英类化合物(DLCs)和结构相关的环境污染物可能通过激活芳烃受体(AHR)并调节下游细胞反应,从而导致各种疾病和紊乱的发病机制。因此,AHR 被认为是预防和治疗措施的有吸引力的分子靶标。然而,由于不同的配体引起明显不同的 AHR 反应,因此 AHR 调节化合物的毒理学风险评估和药物开发变得复杂。通过阐明 PAHs 和 DLCs 对醛酮还原酶 1C3 表达和相关前列腺素 D 代谢的差异影响,我们在此提供证据表明,表皮生长因子受体(EGFR)在人上皮细胞中,即原代和永生化角质形成细胞和乳腺癌细胞中,显著塑造了 AHR 配体诱导的反应。暴露于苯并[a]芘(B[a]P)和二恶英类多氯联苯(PCB)126 导致 EGFR 的快速 c-Src 介导的磷酸化。此外,两种 AHR 激动剂均刺激蛋白激酶 C 活性并增强细胞表面结合的 EGFR 配体的外切酶脱落。然而,只有在 B[a]P 处理下,这个过程导致 EGFR 的自分泌/旁分泌激活,并随后诱导醛酮还原酶 1C3 和前列腺素 D 的 11-酮还原。受体结合和内化测定、对接分析和突变氨基酸交换证实,DLCs 而不是 B[a]P 结合到 EGFR 细胞外结构域,从而阻断生长因子对 EGFR 的激活。最后,纳米孔长读 RNA-seq 揭示了数百个基因,其表达受 B[a]P 调节,但不受 PCB126 调节,并且对药理学 EGFR 抑制敏感。我们的数据为 AHR 信号的配体反应提供了新的机制见解,并确定 EGFR 为环境化学物质的效应物。