Dap10 co-stimulation enhances the anti-HCC efficacy of NKp30 chimeric antigen receptor T cells

Abstract

Chimeric antigen receptor (CAR) T-cell immunotherapy has made significant breakthroughs in the treatment of relapsed or refractory hematologic malignancies, but its efficacy in solid tumors remains limited. In this study, we developed a chimeric NKp30 (chNKp30) receptor whose ligand, B7H6, is often up-regulated in various tumor cells and sparsely expressed in healthy cells. Introduction of the cytoplasmic structural domain of dnax-activating protein 10 (DAP10) into CAR resulted in chNKp30-Dap10 CAR-T cells that showed superior cell proliferation, activation, and apoptosis inhibition after antigenic stimulation compared with conventional chNKp30-CD28 and chNKp30-Wt CAR-T cells lacking any structural domains, along with inducing a central memory T cell phenotype, whereas chNKp30-CD28 and chNKp30-Wt triggered an effector memory phenotype. In addition, chNKp30-Dap10 T cells secreted higher levels of pro-inflammatory cytokines such as IL-2, IFN-γ, and TNF-α, while chNKp30-CD28 T cells secreted more of the anti-inflammatory cytokine IL-10. In the killing assay, chNKp30-Dap10 T cells demonstrated stronger anti-tumor effects. Similarly, better tumor regression was observed in the hepatocellular carcinoma transplantation tumor model. These findings suggest that B7H6 is an attractive therapeutic target and DAP10 signaling is involved in the functional regulation of CAR-T cells in hepatocellular carcinoma, which may induce preferential cytokine profiling and differentiation for cancer therapy, and that NKp30-Dap10 CAR-T cell therapy offers a potential option for the treatment of hepatocellular carcinoma.