Recognition of ErbB Family Dimers by the EGF-like Domain of NRG1alpha and Beta: Implications for Ligand-Based CAR Therapy.

HER-positive cancers comprise a heterogeneous group of malignancies driven by dysregulated activation of the human epidermal growth factor receptor (HER/ERBB) family. While chimeric antigen receptor (CAR) T-cell therapies targeting HER2 have demonstrated potent anti-tumor capabilities, their clinical translation remains hampered by safety hurdles and antigen escape. We developed a modular "Targeted Chimeric Artificial Reporter" (TcAR) system using the natural epidermal growth factor (EGF)-like binding domains of neuregulin-1 (NRG1) isoforms to decode complex HER dimerization profiles. Leveraging the superior targeting plasticity of the β-isoform, we engineered NRG1β-based CAR-T and CAR-natural killer (NK) cells. Our study demonstrates that NRG1β-directed therapy overcomes therapeutic antigen escape in HER2-depleted models and exerts potent anti-tumor activity within complex three-dimensional (3D) tissue microenvironments ex vivo, exhibiting a significantly safer, muted inflammatory profile compared to clinical standards.