N-deglycosylation targeting chimera (DGlyTAC): a strategy for immune checkpoint proteins inactivation by specifically removing N-glycan
Li Li, Jiajia Wu, Weiqian Cao, Wei Zhang, Qi Wu, Yaxu Li, Yanrong Yang, Zezhi Shan, Zening Zheng, Xin Ge, Lin Liang, Ping Wang
Abstract
Among the leading methods for triggering therapeutic anti-cancer immunity is the inhibition of immune checkpoint pathways. N-glycosylation is found to be essential for the function of various immune checkpoint proteins, playing a critical role in their stability and interaction with immune cells. Removing the N-glycans of these proteins seems to be an alternative therapy, but there is a lack of a de-N-glycosylation technique for target protein specificity, which limits its clinical application. Here, we developed a novel technique for specifically removing N-glycans from a target protein on the cell surface, named deglycosylation targeting chimera (DGlyTAC), which employs a fusing protein consisting of Peptide-N-glycosidase F (PNGF) and target-specific nanobody/affibody (Nb/Af). The DGlyTAC technique was developed to target a range of glycosylated surface proteins, especially these immune checkpoints-CD24, CD47, and PD-L1, which minimally affected the overall N-glycosylation landscape and the N-glycosylation of other representative membrane proteins, ensuring high specificity and minimal off-target effects. Importantly, DGlyTAC technique was successfully applied to lead inactivation of these immune checkpoints, especially PD-L1, and showed more potential in cancer immunotherapy than inhibitors. Finally, PD-L1 targeted DGlyTAC showed therapeutic effects on several tumors in vivo, even better than PD-L1 antibody. Overall, we created a novel target-specific N-glysocylation erasing technique that establishes a modular strategy for directing membrane proteins inactivation, with broad implications on tumor immune therapeutics.