Abstract 6493: Comparison of NK-92MI cell line vs. primary NK cells derived from peripheral mononuclear blood cells

Abstract Natural Killer (NK) cell-based therapies are a rapidly growing area in cancer treatment. Preclinical research uses both cell line derived NK cells, such as NK-92MI, and primary NK cells derived from peripheral blood mononuclear cells (PBMCs). Each of these NK cell sources offers distinct advantages and limitations. The NK-92MI cell line, an immortalized and IL-2-independent derivative of the parental NK-92 line, provides a standardized, robust, and easily expandable cell source, making it highly attractive for large-scale experiments. However, NK-92MI cells lack certain activating receptors present in primary NK cells, which may limit their targeting range and reduce their cytotoxic potential against specific cancer types. Conversely, primary NK cells isolated from PBMCs mirror more closely the heterogeneous and receptor-diverse populations present in the human immune system. Yet, primary NK cells also present challenges, including variability between donors, limited proliferation in culture, and complex handling and isolation processes. This study compared the cytotoxic efficacy of the NK-92MI cell line and primary NK cells against HER2+ cancer cells in combination with trastuzumab (anit-HER2 antibody). Using a live-cell imaging platform, we quantitatively assessed the killing dynamics of these NK cell types over time. HER2+ cancer cells (SK-OV3, SK-BR3, HCC1954, JIMT-1) were co-cultured with either NK-92MI cells or PBMC-derived NK cells, and their effect on tumor cell killing was monitored continuously in a 2D and 3D setup. In addition, the migration of different NK cell types through a trans-well membrane was measured to see their migration potential. Key parameters, including the rate of cancer cell death and NK migration activity, were analyzed to determine differences in killing efficiency and sustained potency. The results indicate differential cytotoxic behavior between PBMC-derived NK cells and NK92-MI. In monotherapy the NK92-MI cell line exhibited strong proliferation and increased cytotoxic activity compared to PBMC-derived NK cells, which demonstrated moderate tumor cell killing. However, the treatment with trastuzumab in the presence of the two different NK cell types displayed equally effective killing. Despite JIMT-1 which was resistant towards trastuzumab but displayed reduced growth over time when co-cultured with NK-92MI alone. The migratory capacity of the NK cells was mainly driven by the different CCL2 levels secreted by the four HER2+ cancer cell lines evaluated in the study. In summary, this study highlights the feasibility to use NK cell lines such as NK-92MI for screening and proof-of concept experiments, where the need for scalability and reproducibility is mandatory. However, the limited heterogeneity and lack of certain activating receptors of the NK cell line must be considered when interpreting these studies. Citation Format: Ina Rohleff, Kanstantsin Lashuk, Julia B. Schueler. Comparison of NK-92MI cell line vs. primary NK cells derived from peripheral mononuclear blood cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6493.