表皮生长因子受体（EGFR）是癌症治疗的重要靶点。据报道，许多头颈癌 (HNC) 细胞过度表达 EGFR；因此，已经尝试对 HNC 患者进行抗 EGFR 治疗。然而，由于耐药性的产生，其临床疗效受到限制。在这项研究中，我们开发了一种 EGFR 靶向免疫毒素，由临床证明的抗 EGFR I​​gG（西妥昔单抗；CTX）和源自假单胞菌外毒素 A (PE) 的毒素片段 (LR-LO10) 组成，使用新型位点特异性缀合技术（肽定向光交联反应），作为替代选择。免疫毒素（CTX-LR-LO10）表现出与 EGFR 的特异性结合和典型 IgG 的特性，例如稳定性、与免疫细胞受体的相互作用和药代动力学，并通过修饰延伸因子 2 抑制蛋白质合成。用免疫毒素处理 EGFR 阳性 HNC 细胞会导致细胞凋亡并抑制细胞迁移和侵袭。在异种移植小鼠模型中评估了 CTX-LR-LO10 的功效，免疫毒素表现出比 CTX 或 LR-LO10 更强的肿瘤抑制作用。转录组分析表明，免疫毒素会引发免疫反应，并改变与其作用机制相关的基因表达。这些结果支持了 CTX-LR-LO10 可能作为一种针对 EGFR 阳性癌症的新治疗剂的观点。© 2024 美国实验生物学会联合会。

The epidermal growth factor receptor (EGFR) is an important target for cancer therapies. Many head and neck cancer (HNC) cells have been reported to overexpress EGFR; therefore, anti-EGFR therapies have been attempted in patients with HNC. However, its clinical efficacy is limited owing to the development of drug resistance. In this study, we developed an EGFR-targeting immunotoxin consisting of a clinically proven anti-EGFR IgG (cetuximab; CTX) and a toxin fragment (LR-LO10) derived from Pseudomonas exotoxin A (PE) using a novel site-specific conjugation technology (peptide-directed photo-crosslinking reaction), as an alternative option. The immunotoxin (CTX-LR-LO10) showed specific binding to EGFR and properties of a typical IgG, such as stability, interactions with receptors of immune cells, and pharmacokinetics, and inhibited protein synthesis via modification of elongation factor-2. Treatment of EGFR-positive HNC cells with the immunotoxin resulted in apoptotic cell death and the inhibition of cell migration and invasion. The efficacy of CTX-LR-LO10 was evaluated in xenograft mouse models, and the immunotoxin exhibited much stronger tumor suppression than CTX or LR-LO10. Transcriptome analyses revealed that the immunotoxins elicited immune responses and altered the expression of genes related to its mechanisms of action. These results support the notion that CTX-LR-LO10 may serve as a new therapeutic agent targeting EGFR-positive cancers.© 2024 Federation of American Societies for Experimental Biology.