Modification with IL-21 and CCL19 enhances killing efficiency and tumor infiltration of NKP30 CAR-T cells in lung cancer
Objective To investigate whether modification with IL-21 and CCL19 enhances killing and tumor-infiltrating efficiency of NKP30 CAR-T cells in lung cancer.Methods The modified IL-21-CCL19 NKP30 CAR-T cells expressing IL-21 and CCL19 fusion gene was constructed based on NKP30 CAR-T cells and stimulated with CD3CD28 antibodies and IL-2.The immunophenotype and migration of the cells in the presence of IL-21 were investigated using flow cytometry and migration experiments.Lactate dehydrogenase(LDH)release and sphere formation assays were used to assess the killing and infiltration capabilities of CAR-T cells,and the secretion levels of IFN-γ,IL-21 and CCL19 were determined with enzyme-linked immunospot assay(ELISPOT)and ELISA.A zebrafish model bearing HCG-27 cell xenograft was established by microinjection of the tumor cells into the yolk sac followed 24 h later by injection of the immune cells at the same site,and the fluorescence signals were captured using a fluorescent microscopy.Results The NKP30 ligand B7H6,which was almost undetectable in normal tissues and blood cells,was highly expressed(over 90%)in lung cancer cells.Compared with NKP30 CAR-T cells and conventional T cells,IL-21-CCL19 NKP30 CAR-T cells exhibited stronger proliferative and migration capabilities with the formation of central memory T cells.The reduced expressions of CTLA4 and PD1 in the constructed cells resulted in enhanced killing efficiency against lung cancer cells accompanied by significantly increased production of IFN-γ,IL-21 and CCL19.In the zebrafish models,CAR-T cells exhibited stronger cytotoxicity and proliferative abilities than typical T cells,but these differences were not statistically significant between the two CAR-T cells.Conclusion Modification of NKP30 CAR-T cells with IL-21 and CCL19 facilitates their access into solid tumors for more effective tumor cell killing while producing a large number of memory T cells.