Characterization of <i>ex vivo</i> expanded natural killer cells for cancer immunotherapy

In this study, we employed a coculture system to expand natural killer (NK) cells ex vivo from healthy donors and patients with breast cancer and investigated their surface marker expression. We further analyzed the activation markers of primary expanded NK cells on Day 13 using cytokine arrays and dimensionality reduction techniques. Cytokine profiles were observed on Days 0, 6 and 13 (TS-NK). To validate the anticancer activity of the expanded NK cells, we conducted lactate dehydrogenase assays against the hematologic cancer cell line K562 using cells from 10 donors (five patients with cancer and five healthy individuals). Additionally, we examined the antibody-dependent cellular cytotoxicity (ADCC) of differentiated NK cells cocultured with SK-BR-3 cells in the presence of the HER2-targeting monoclonal antibodies, trastuzumab and pertuzumab. Our findings demonstrate the stable expansion of NK cells from donor peripheral blood mononuclear cells and their potent anticancer effects and ADCC against both hematologic and solid tumors, highlighting their potential as a versatile therapeutic approach in oncology.