Solid tumor immunotherapy using NKG2D-based adaptor CAR T cells

Abstract

NKG2D ligands (NKG2DLs) are broadly expressed in cancer. To target these, we describe an adaptor chimeric antigen receptor (CAR) termed NKG2D/Dap10-12 . Herein, T cells are engineered to co-express NKG2D with a fusion protein that comprises Dap10 joined to a Dap12 endodomain. NKG2D/Dap10-12 T cells elicit compelling efficacy, eradicating or controlling NKG2DL-expressing tumors in several established xenograft models. Importantly, durable responses, long-term survival, and rejection of tumor re-challenge are reproducibly achieved. Efficacy is markedly superior to a clinical stage CAR analog, comprising an NKG2D-CD3ζ fusion. Structure-function analysis using an extended CAR panel demonstrates that potency is dependent on membrane proximity of signaling units, high NKG2D cell surface expression, adaptor structure, provision of exogenous Dap10, and inclusion of one rather than three immune tyrosine activation motifs per signaling unit. Potent therapeutic impact of NKG2D/Dap10-12 T cells is also underpinned by enhanced oxidative phosphorylation, reduced senescence, and transcriptomic re-programming for increased ribosomal biogenesis. • NKG2D naturally associates with the adaptor molecule, Dap10 • Addition of Dap12 to the Dap10 C terminus yields a potent NKG2D-based CAR • The resulting adaptor CAR configuration promotes functional persistence of T cells • As a result, adaptor CAR T cells mediate enhanced anti-tumor activity NKG2D ligands are widely expressed by solid tumors providing an attractive targeting opportunity with NKG2D-based CAR T cells. Here, Obajdin et al. show that this is optimally achieved using an adaptor CAR format in which signaling is provided by highly compact Dap10 and Dap12 signaling units.