Clinical-grade ex vivo -expanded human natural killer cells up-regulate activating receptors and death receptor ligands and have enhanced cytolytic activity against tumor cells

• Published in: Cytotherapy (Oxford, England) Vol. 11; no. 3; pp. 341 - 355
• Main Authors: Berg, Maria, Lundqvist, Andreas, McCoy, Philip, Samsel, Leigh, Fan, Yong, Tawab, Abdul, Childs, Richard
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.01.2009; Informa UK Ltd
• Subjects: Advanced Basic Science; Boronic Acids - pharmacology; Bortezomib; Carcinoma, Renal Cell - drug therapy; Carcinoma, Renal Cell - immunology; Carcinoma, Renal Cell - pathology; Cell Culture Techniques; Cell Proliferation; Cryopreservation; Cytokines - metabolism; Cytotoxicity, Immunologic - immunology; expansion; Fas Ligand Protein - genetics; Fas Ligand Protein - immunology; Fas Ligand Protein - metabolism; Humans; Immunophenotyping; immunotherapy; Immunotherapy - methods; K562 Cells; Killer Cells, Natural - immunology; Killer Cells, Natural - metabolism; Killer Cells, Natural - pathology; Lymphocyte Activation; natural killer cells; NK Cell Lectin-Like Receptor Subfamily K - genetics; NK Cell Lectin-Like Receptor Subfamily K - immunology; NK Cell Lectin-Like Receptor Subfamily K - metabolism; Other; Pyrazines - pharmacology; TNF-Related Apoptosis-Inducing Ligand - genetics; TNF-Related Apoptosis-Inducing Ligand - immunology; TNF-Related Apoptosis-Inducing Ligand - metabolism; Up-Regulation; natural killer cells; Bortezomib; immunotherapy; expansion
• ISSN: 1465-3249; 1477-2566
• DOI: 10.1080/14653240902807034

Background aims Cancer immunotherapy involving natural killer (NK) cell infusions and administration of therapeutic agents modulating the susceptibility of tumors to NK-cell lysis has been proposed recently. We provide a method for expanding highly cytotoxic clinical-grade NK cells in vitro for adoptive transfer following bortezomib treatment in patients with advanced malignancies. Methods NK cells were expanded with irradiated Epstein–Barr virus-transformed lymphoblastoid cells. Expanded cells were evaluated for their phenotype, cytotoxicity, cytokine secretion, dependence on interleukin (IL)-2 and ability to retain function after cryopreservation. Results A pure population of clinical-grade NK cells expanded 490 ± 260-fold over 21 days. Expanded NK cells had increased TRAIL, FasL and NKG2D expression and significantly higher cytotoxicity against bortezomib-treated tumors compared with resting NK cells. Expanded NK cells, co-cultured with K562 and renal cell carcinoma tumor targets, secreted significantly higher levels of soluble Fas ligand 6; fgjhd IFN-γ, GM-CSF, TNF-α, MIP-1α and MIP-1β compared with resting NK cells. Secretion of the above cytokines and NK-cell cytolytic function were IL-2 dose dependent. Cryopreservation of expanded NK cells reduced expression of NKG2D and TRAIL and NK-cell cytotoxicity, although this effect could be reversed by exposure of NK cells to IL-2. Conclusions We describe a method for large-scale expansion of NK cells with increased expression of activating receptors and death receptor ligands resulting in superior cytotoxicity against tumor cells. This ex vivo NK-cell expansion technique is currently being utilized in a clinical trial evaluating the anti-tumor activity of adoptively infused NK cells in combination with bortezomib.