Tumor Cell-Specific Metabolic Labelling of Surface Sialoglycans and Post-Click with Multivalent Rhamnose Enable Precise Immune Killing by Endogenous Antibody

Abstract

We report the design and development of a β-glucuronidase (β-Glu)-responsive ManNAz derivative, Glu-AAM, for tumor-selective metabolic glycoengineering. Glu-AAM enables specific labeling of tumor cell surface sialoglycans in the presence of overexpressed β-Glu in cancer cells, including breast, leukemia, and colorectal cancer cells. We demonstrate the high selectivity and efficiency of Glu-AAM-mediated metabolic glycoengineering across multiple cancer cell lines. Furthermore, we synthesized multivalent antibody-recruiting molecules (DBCO-Rha) that can be covalently attached to the azido-modified tumor cell surface, leading to potent antibody-dependent cellular phagocytosis and complement-dependent cytotoxicity. The octameric DBCO-Rha8 construct exhibited the most effective immune response. This integrated strategy of β-Glu-responsive metabolic glycoengineering and antibody-recruiting immunotherapy provides a promising platform for targeted cancer therapies and expands the toolbox of metabolic glycoengineering for cancer immunotherapy.