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Adoptive chimeric antigen receptor (CAR)-modified T or NK cells (CAR-T/NK) have emerged as a novel form of disease treatment. Lentiviral vectors (LVs) are commonly employed to engineer NK cells for the efficient expression of CARs. This study reported the influence of single-promoter and dual-promoter LVs on the CAR expression and cytotoxicity of engineered NK cells. We constructed a third-generation NKG2D-based CAR that kills cancer cells by targeting up to eight stress-induced ligands (NKG2DLs). Our results demonstrated that the CAR exhibits both a higher expression level and a higher coexpression concordance with the GFP reporter in HEK-293T or NK92 cells by utilizing the optimized single-promoter pCDHsp rather than the original dual-promoter pCDHdp. After puromycin selection, the pCDHsp produces robust CAR expression and enhanced in vitro cytotoxicity of engineered NK cells. Therefore, infection with a single-promoter pCDHsp lentivector is recommended to prepare CAR-engineered NK cells. This research helps to optimize the production of CAR-NK cells and enhance their functional activity, to provide CAR-NK cell products with better and more uniform quality. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR)-modified immune cells have emerged as a promising approach for cancer treatment, but single-target CAR therapy in solid tumors is limited by immune escape caused by tumor antigen heterogeneity and shedding. Natural killer group 2D (NKG2D) is an activating receptor expressed in human NK cells, and its ligands, such as MICA and MICB (MICA/B), are widely expressed in malignant cells and typically absent from healthy tissue. NKG2D plays an important role in anti-tumor immunity, recognizing tumor cells and initiating an anti-tumor response. Therefore, NKG2D-based CAR is a promising CAR candidate. Nevertheless, the shedding of MICA/B hinders the therapeutic efficacy of NKG2D-CARs. Here, we designed a novel CAR by engineering an anti-MICA/B shedding antibody 1D5 into the CAR construct. The engineered NK cells exhibited significantly enhanced cytotoxicity against various MICA/B-expressing tumor cells and were not inhibited by NKG2D antibody or NKG2D-Fc fusion protein, indicating no interference with NKG2D-MICA/B binding. Therefore, the developed 1D5-CAR could be combined with NKG2D-CAR to further improve the obstacles caused by MICA/B shedding. • 1D5-CAR targeting MICA/B α3 was designed based on structure. • 1D5-CAR-modified NK cells exhibited potent cytotoxicity. • 1D5-CAR didn't disturb NKG2D-MICA/B interaction. • 1D5-CAR could be combined with NKG2D-CAR. [ABSTRACT FROM AUTHOR]

Engineered natural killer (NK) cell-based therapies have been potentially broadly applicable and exhibited promising results in clinical trials, particularly in the fight against cancers. NK cell immunotherapy however always remains variable. One major obstacle is the inhibitory pathway including PD1/PDL1, providing tumor cells an escape mechanism from immunosurveillance. In this regard, we rationally designed a chimeric switch-receptor (CSR) PD1-DAP10-41BB, which comprising the ectodomain of PD1 fused to the co-stimulatory receptor DAP10 and 41BB. Therefore, by exchanging the transmembrane and cytoplasmic tail of PD1 with positive costimulatory molecules DAP10 and 41BB signaling domains, the negative PD1/PDL1 signal pathway was thus converted into a positive one. This CSR-expressing NK92 cells showed a typical parental NK92 phenotype and improved cytotoxicity against human lung cancer H1299 cells. Besides, the expression of CSR elicited a significant increase of effector molecules such as perforin and granzymes, which can induce apoptosis of H1299 cells. More importantly, in the solid tumor cell H1299-bearing mice model, the CSR-modified NK92 cells significantly inhibited tumor growth. Collectively, we demonstrated that expression of PD1-DAP10-41BB augmented NK92-cell activation and killing in vitro and in vivo , which provides a considerable avenue of using NK-tailored chimeric receptor engineered NK92 cells to treat a wide range of solid tumors. • A novel NK-tailored chimeric switch-receptor PD1-DAP10-41BB is rationally designed. • Modified NK92 cells mediate the clearance of H1299 cells by triggering apoptosis. • PD1-DAP10-41BB-expressing NK92 cells elicit in vivo tumor control of H1299 cells. [ABSTRACT FROM AUTHOR]