CD147-CAR-NK cell therapy shows minimal toxicities in human CD147 transgenic mouse model with solid tumors.

The toxicity of chimeric antigen receptor-natural killer (CAR-NK) therapy has not been tested in solid tumors, compared with CAR-T therapy side by side. To address this, we investigated the CD147-CAR-NK "on-target/off-tumor" toxicity and neurotoxicity in human CD147-transgenic (hCD147TG) mice with hepatocellular carcinoma (HCC). We first tested the in vitro cytotoxicity of CD147-CAR-NK against CD147(+) tumor and CD147(+) healthy cells. Both CD147-CAR-NK cells and CD147-IL15-CAR-NK (autocrine expressing interleukin [IL]-15) can kill tumor cells specifically but not CD147(+) healthy lung and spleen tissue from hCD147TG mice. In vivo assays show minimal systemic toxicities against CD147(+) healthy tissues but 1-week-longer persistence times in tumor than non-tumor tissues. To evaluate neurotoxicity, we compared the expression of ionized calcium-binding adaptor protein 1 (IBA1), glial fibrillary acidic protein (GFAP), and inducible nitric oxide synthase (iNOS) between CD147-CAR-T- and CD147-CAR-NK-treated hCD147TG mice with HCC. Both CD147-CAR-T- and CD147-CAR-NK-treated mice exhibited higher GFAP and IBA1 expression than control groups. CD147-CAR-T-treated mice showed an increase in iNOS compared to the control groups. The behavioral studies testing spatial memory showed that mice treated with CD147-CAR-NK exhibit better memory function than CD147-CAR-T-treated mice. This study provides a deeper understanding of the CD147-CAR-NK systemic toxicities and neurotoxicity of CD147-CAR-NK relative to CD147-CAR-T therapy.