BioProject

NK-92 cells and their CAR-modified derivatives exhibit strong cytotoxic activity against tumors and are promising "off-the-shelf" therapeutics compared to CAR-T cells. More...

NK-92 cells and their CAR-modified derivatives exhibit strong cytotoxic activity against tumors and are promising "off-the-shelf" therapeutics compared to CAR-T cells. In order to ensure safety and prevent the occurrence of secondary tumors, (CAR-)NK-92 cells need to be inactivated before transfusion. With increasing clinical use, there is a growing demand for enhanced safety and an efficient method that stops cell proliferation, but better maintains the cytotoxic effector functions of the cells compared to commonly used gamma irradiation. Recently, low-energy electron irradiation (LEEI) was successfully applied for inactivation of bacteria and viruses for vaccine production, and was described as a method for NK-92 inactivation for the first time. In the present publication, data on extensive characterization of LEEI and its comparison with gamma irradiation for the inactivation of parental NK-92 cells as well as CD123-directed CAR-NK-92 cells are provided. Our results show that both irradiation methods cause a progressive decrease in cell viability and are therefore suitable for inhibition of proliferation. Notably, cytotoxicity of the NK cells was significantly reduced by gamma irradiation, but not by LEEI three days after irradiation, compared to non-irradiated cells. Both gamma irradiation as well as LEEI led to substantial DNA-damage and an accumulation of irradiated cells in the G2/M phase. In addition, transcriptomic analysis of cells irradiated with both methods revealed approximately 12-fold more differentially expressed genes after gamma irradiation compared to LEEI. Analysis of surface molecules revealed an irradiation-induced decrease in CD56 expression but no changes in the levels of the activating receptors NKp46, NKG2D, and NKp30. Conclusions: The present data show that LEEI efficiently inactivates (CAR )NK-92 cells and sustains their cytotoxic capacity better than gamma irradiation. Taking into account additional logistic advantages of LEEI proves a potent alternative in the manufacturing of (CAR-)NK-92 cells for clinical application. Overall design: RNA expression of three LEEI-irradiated, three gamma-irradiated and three non-irradiated (control) CAR-NK cell samples Less...