RESUMO
Natural killer (NK) cells are an important effector cell type for adoptive cancer immunotherapy. Similar to T cells, NK cells can be modified to express chimeric antigen receptors (CARs) to enhance antitumor activity, but experience with CAR-engineered NK cells and their clinical development is still limited. Here, we redirected continuously expanding and clinically usable established human NK-92 cells to the tumor-associated ErbB2 (HER2) antigen. Following GMP-compliant procedures, we generated a stable clonal cell line expressing a humanized CAR based on ErbB2-specific antibody FRP5 harboring CD28 and CD3ζ signaling domains (CAR 5.28.z). These NK-92/5.28.z cells efficiently lysed ErbB2-expressing tumor cells in vitro and exhibited serial target cell killing. Specific recognition of tumor cells and antitumor activity were retained in vivo, resulting in selective enrichment of NK-92/5.28.z cells in orthotopic breast carcinoma xenografts, and reduction of pulmonary metastasis in a renal cell carcinoma model, respectively. γ-irradiation as a potential safety measure for clinical application prevented NK cell replication, while antitumor activity was preserved. Our data demonstrate that it is feasible to engineer CAR-expressing NK cells as a clonal, molecularly and functionally well-defined and continuously expandable cell therapeutic agent, and suggest NK-92/5.28.z cells as a promising candidate for use in adoptive cancer immunotherapy.
Assuntos
Expressão Gênica , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Receptor ErbB-2/imunologia , Receptores Imunológicos/genética , Receptores Imunológicos/imunologia , Proteínas Recombinantes de Fusão/genética , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/imunologia , Neoplasias da Mama/terapia , Linhagem Celular Transformada , Linhagem Celular Tumoral , Evolução Clonal , Citotoxicidade Imunológica , Modelos Animais de Doenças , Epitopos de Linfócito T/imunologia , Feminino , Vetores Genéticos/genética , Humanos , Imunofenotipagem , Imunoterapia , Lentivirus/genética , Teste de Cultura Mista de Linfócitos , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/patologia , Neoplasias/terapia , Fenótipo , Transdução Genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Natural killer (NK) cells hold promise for adoptive cancer immunotherapy but are dependent on cytokines such as interleukin (IL)-2 for growth and cytotoxicity. Here, we investigated the consequences of ectopic expression of IL-15 in human NK cells. IL-2 and IL-15 belong to the common γ chain family of cytokines and have overlapping activities. Transduction of clinically applicable NK-92 cells with lentiviral vectors encoding human IL-15 resulted in predominantly intracellular expression of the cytokine, and STAT5 activation, proliferation and cytotoxicity of the producer cells in the absence of IL-2. Growth of non-transduced bystander cells was not supported, allowing rapid enrichment of gene-modified cells solely by IL-2 withdrawal. This was also the case upon transduction of NK-92 and NKL cells with a bicistronic lentiviral vector encoding IL-15 and a chimeric antigen receptor (CAR) targeting the pancarcinoma antigen EpCAM. Effector cells co-expressing CAR and IL-15 continued to proliferate in the absence of exogenous cytokines and displayed high and selective cell-killing activity against EpCAM-expressing breast carcinoma cells that were resistant to the natural cytotoxicity of unmodified NK cells. This strategy facilitates rapid isolation and continuous expansion of retargeted NK cells and may extend their potential clinical utility.