Amber Bouren

Engineering CAR T cells to secrete VEGF-neutralizing scFvs enhances antitumor activity against solid tumors

Chimeric antigen receptor (CAR) T cell therapy has shown limited efficacy against solid tumors, which often reside in highly immunosuppressive tumor microenvironments (TMEs). TMEs can be highly abundant in vascular endothelial growth factor A (VEGF), which contributes to immunosuppression and abnormal tumor vasculature. Here, we found that CAR T cells engineered to secrete an anti-VEGF single-chain variable fragment (CAR-αVEGF T cells) achieved superior antitumor efficacy against multiple in vivo models of ovarian cancer and glioma, outperforming conventional CAR T cells with and without combination anti-VEGF antibody therapy. Microscopy, flow cytometry, and transcriptomic analyses revealed that armoring the CAR T cells with anti-VEGF single-chain variable fragments enhanced their activation and mitochondrial fitness and enriched immune-stimulatory signatures among endogenous immune cells in the tumor-bearing brain. Moreover, CAR-αVEGF T cells circumvented multiple detrimental effects associated with on-target CAR T cell therapy, including infiltration of suppressive myeloid cells, exaggerated vasculature abnormalities, and hypoxia. Together, our results provide rationale for the clinical translation of CAR-αVEGF T cells as a safe and potent therapy for solid tumors characterized by elevated VEGF.