Targeted Therapy of CEA-CAR-NK Cells Against Colorectal Cancer Cells

Objective: Investigate the cytotoxic effect of CAR-NK cells targeting CEA on colorectal cancer cells with positive CEA expression. Methods: The mRNA and protein levels of CEA in different CRC cell lines were detected by qRT-PCR and Western blot analysis. Lentiviral transduction was used to construct CAR-NK cells and empty vector CON-NK cells targeting CEA. Fluorescence microscopy and WB were used to determine whether the cells successfully constructed and expressed CAR structures. The effector NK cells were co-cultured with target cells, and the levels of LDH, IFN-γ, and GM-CSF were detected. The killing rate of effector cells was calculated, and the release of cytokines during the killing of target cells by different effector cells was compared. Results: The expression level of CEA in colorectal cancer patients was significantly higher than that in normal samples and other tumor samples, and the prognosis survival time of patients with high CEA expression was lower than that of CRC patients with low or no CEA expression (P < 0.05). The CEA expression of the HT29 cell line was significantly higher than that of the SW1116 cell line at both the mRNA and protein levels. CEA-CAR-NK92 cells and CON-NK92 cells expressed green fluorescence under a microscope, and WB results showed that CEA-CAR-NK92 cells successfully expressed the CAR structure. Compared with CON-NK92 cells and NK92 cells, CEA-CAR-NK92 cells effectively killed HT29 cells (P < 0.05). CEA-CAR-NK92 cells secreted a large amount of IFN-γ and GM-CSF during the killing of HT29 cells, while the cytokine secretion of CON-NK92 cells and NK92 cells was not significant (P < 0.05). Conclusion: CAR-NK92 cells targeting CEA can effectively kill CEA-positive colorectal cancer cells.