Ephrin A1 ligand-based CAR-T cells for immunotherapy of EphA2-positive cancer

Abstract

Chimeric antigen receptor (CAR) T cells have demonstrated promising results in hematological malignancies; however, challenges remain in treating solid tumors. New CARs with more effectiveness and lower side effects are needed. Ephrin type-A receptor 2 (EphA2) belongs to the Ephrin family of receptor tyrosine kinases, which is overexpressed in several solid malignancies. Compared with some single-chain variable fragment (ScFv) CARs that exhibit excessively high affinity for their targets, natural receptor/ligand-based CARs maintain inherent affinity for their binding partners, potentially balancing cytotoxicity and side effects to better meet clinical needs. Here, we designed a CAR targeting EphA2-positive cancer cells by exploiting the extracellular domain of its natural ligand Ephrin A1 (EFNA1). EFNA1 CAR-T cells exhibited specific cytotoxicity against various cancer cells and cancer stem-like cells in vitro, and significantly suppressed tumor growth in a pancreatic cancer xenograft mouse model. Moreover, although these CAR-T cells specifically targeted mouse EphA2 and killed mouse tumor cell lines in vitro, they did not induce obvious side effects in mice. Additionally, it also showed good safety in rhesus macaques. Collectively, these results validate the therapeutic effectiveness and safety of EFNA1 CAR-T cells for treating solid tumors.