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Solid tumor immunotherapy using NKG2D-based adaptor CAR T cells
Jana Obajdin1, Daniel Larcombe-Young1, Maya Glover2
1King's College London, School of Cancer and Pharmaceutical Sciences, CAR Mechanics Lab, London SE1 9RT, UK.
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.
Insights
Engineered T cells targeting NKG2D ligands (NKG2DLs) show potent anti-tumor activity. The novel NKG2D/Dap10-12 chimeric antigen receptor (CAR) therapy eradicates tumors and improves survival in models.
Area of Science:
- Immunology
- Cancer Biology
- Cell Therapy
Background:
- NKG2D ligands (NKG2DLs) are widely expressed on cancer cells, presenting a therapeutic target.
- Existing chimeric antigen receptor (CAR) strategies have limitations in targeting NKG2DL-expressing tumors.
Purpose of the Study:
- To develop and evaluate a novel adaptor CAR, termed NKG2D/Dap10-12, for targeting NKG2DLs on cancer cells.
- To assess the efficacy and underlying mechanisms of NKG2D/Dap10-12 CAR T cells in preclinical cancer models.
Main Methods:
- Engineering T cells to co-express NKG2D with a fusion protein comprising Dap10 and a Dap12 endodomain (NKG2D/Dap10-12 CAR).
- Evaluating therapeutic efficacy in established xenograft models with NKG2DL-expressing tumors.
- Conducting structure-function analysis across a panel of CARs to identify key determinants of potency.
- Analyzing cellular metabolism and transcriptomics of engineered T cells.
Main Results:
- NKG2D/Dap10-12 T cells demonstrated compelling efficacy, eradicating or controlling tumors in multiple xenograft models.
- Durable responses, long-term survival, and rejection of tumor re-challenge were achieved.
- Efficacy significantly surpassed that of a clinical-stage NKG2D-CD3ζ CAR.
- Potency was linked to signaling unit proximity, NKG2D expression, adaptor structure, exogenous Dap10, and ITIM number.
Conclusions:
- The NKG2D/Dap10-12 CAR represents a potent new strategy for targeting NKG2DL-expressing cancers.
- Optimized CAR design, including adaptor structure and signaling motifs, is crucial for therapeutic efficacy.
- NKG2D/Dap10-12 CAR T cells exhibit enhanced metabolic fitness and reprogrammed transcription for improved anti-tumor function.
