Redirection of CAR-T Cell Cytotoxicity Using Metabolic Glycan Labeling with Unnatural Sugars

Abstract

T cells expressing chimeric antigen receptors (CAR-Tcells) haveshown unprecedented clinical responses against hematological malignancies.However, some patients relapse after CAR-T cell therapy due to antigen-negativeescape variants. Additionally, CAR-T cell therapies showed limitedclinical efficacy in solid tumors with high antigen heterogeneity.To overcome this, we metabolically labeled the glycans on cancer cellsto redirect CAR-T cell cytotoxicity regardless of the endogenous antigenexpression status of the cancer cells. We found that modifying cancercells with N-azidoacetylmannosamine and bicyclo[6.1.0]non-4-yne-fluoresceinisothiocyanate can elicit selective and durable cytotoxicity of anti-FITCCAR-T cells. Furthermore, we demonstrated that dinitrophenyl-conjugatedsialic acid (Sia-DNP) generated DNP-modified glycans on cancer cellsin situ that could be effectively targeted by anti-DNP CAR-T cellsto eradicate established tumors in xenograft models. Our study illustratesthat metabolic glycan labeling using unnatural sugars can be combinedwith CAR-T cell therapy to provide novel cancer immunotherapy forsolid tumors that lack viable target antigens.