Click Chemistry Mediated Immune Synapse Augmentation in Natural Killer Cell-Cancer Membrane Engagement and Facilitated Anticancer Efficacies of Natural Killer Cell Therapy.

Abstract

Non-small cell lung cancer remains a major clinical challenge due to aggressive metastasis and limited therapeutic modalities. The innate cytotoxicity of natural killer (NK) cells and their ability to eliminate malignant cells in an antigen-independent manner have attracted considerable interest for cancer immunotherapy. However, the therapeutic performance of NK cells in solid tumors is severely constrained by (a) tumor heterogeneity, (b) physical barriers within the tumor microenvironment, and (c) insufficient tumor-targeting specificity. To address these challenges, we here develop a lipid biomaterial that enables the simultaneous surface engineering of cancer and NK cells to enhance their physical engagement within complex tumor microenvironments. The developed lipid biomaterials are composed of (a) a lipid moiety for stable surface anchoring and (2) complementary dibenzocyclooctyne (DBCO) and azide (N₃) functional groups to mediate bioorthogonal click-reaction-driven cell-cell interactions. This modular design allows the rapid and non-genetic engineering of cell surfaces, promoting tumor-specific targeting through DBCO-N₃ click reactions, while simultaneously enhancing NK cell activation and cytotoxic function. Surface engineering of non-small cell lung cancer cells (N₃-cancer) and NK cells (D-NK) using lipid-N₃ and lipid-DBCO substantially improved cancer recognition, immune activation, and NK cell-mediated cytotoxicity. Moreover, lipid-N₃ successfully labeled 3-dimensional lung tumoroids embedded in collagen hydrogels that recapitulate the structure of native lung tissue, leading to superior antitumor efficacy upon interaction with D-NK cells. Collectively, this lipid-biomaterial-based strategy provides a versatile, receptor-independent approach to augment NK cell-based immunotherapy against heterogeneous solid tumors, offering a promising approach that avoids reliance on predefined tumor-specific ligand-receptor pairs.