Antitumor Activity of a Bispecific Chimera Targeting EGFR and Met in Gefitinib‐Resistant Non‐Small Cell Lung Cancer

Abstract Non‐small cell lung cancers (NSCLC) frequently acquire resistance to tyrosine kinase inhibitors (TKI) due to epidermal growth factor receptor (EGFR) mutation or activation of the bypass pathway involving mesenchymal‐epithelial transition factor (Met). To address this challenge, a bispecific nanobody‐aptamer chimera is designed to target mutated EGFR and Met simultaneously to block their cross‐talk in NSCLC. The EGFR‐Met chimera is cost‐effectively engineered using microbial transglutaminase and click chemistry strategies. With enhanced binding affinity toward the target proteins, the as‐developed chimera inhibits efficiently the cross‐talk between signaling pathways associated with EGFR and Met. This inhibition leads to the suppression of downstream pathways, such as Erk and Akt, and induces upregulation of cell cycle arrest‐related proteins, including Rb, p21, and p27. Additionally, the chimera activates the caspase‐dependent apoptotic signaling pathway. Consequently, it inhibits cell migration, induces cell death, and causes cell cycle arrest in vitro. Moreover, the chimera exhibits significant antitumor efficacy in drug‐resistant xenograft mouse models, showcasing improved tissue penetration and low toxicity. This study accentuates the potential of the bispecific EGFR‐Met chimera as a promising therapeutic option for NSCLC resistant to EGFR TKIs.