Selective Inhibition of Tumor Growth by Clonal NK Cells Expressing an ErbB2/HER2-Specific Chimeric Antigen Receptor

Abstract

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.

DAP12-Based Activating Chimeric Antigen Receptor for NK Cell Tumor Immunotherapy

“…As a likely consequence of ZAP-70-mediated signal induction, CAR-modified YTS cells released significantly increased amounts of IFN-g when compared with controls. At the same time, no obvious correlation between the amounts of IFN-g secretion by YTS cells and target Ag expression was detectable, which resembles results obtained by CD3z-CAR-modified NK92 cells engaging different ErbB2/HER-2-positive target cell lines (67). In line with the aforementioned observation, also the strength of the cytotoxic reaction as well as the IFN-g release of CAR-modified primary NK cells was not directly correlated to the level of PSCA expression on target cells.…”

“…However, concern has been raised about genetically modified autoreactive T cells, which might cause undesirable side effects after infusion into patients. NK cells, in contrast, do not possess TCR-like molecules that might (21,(41)(42)(43)(65)(66)(67)(68).…”

“…3 were also incubated with the bladder carcinoma cell lines RT4 and HT1376, which show endogenous expression of PSCA. *p , 0.05. edge, we treated for the first time established solid tumors with CAR-modified NK cells, whereas other groups favored mixing of NK cells and target cells prior to tumor transplantation (23,(65)(66)(67) or chose an experimental setting that most likely confronts injected tumor cells and CAR-modified NK cells in the bloodstream or lung capillaries (67). In this article, we demonstrate that treatment with YTS anti-PSCA-DAP12 NK cells resulted in a significantly delayed growth of PSCA-positive tumors when compared with tumors treated with YTS wt cells and YTS myc-DAP12 controls, respectively.…”

NK cells and cancer: you can teach innate cells new tricks

“…142) and CD20 (REF. 143) expressed on B cell malignancies; disialoganglioside G D2 , a glycolipid expressed on neuroblastoma 144 and various other cancer types 145 ; HER2 (also known as ERBB2), an antigen expressed by tumours of epithelial origin [146][147][148] ; epithelial cell adhesion molecule (EPCAM), a molecule over expressed by carcinomas and cancer stem cells 149 ; HLA-A2 loaded with the mela noma antigen gp100 (also known as PMEL) 150 ; prostate stem cell antigen (PSCA) 151 ; and CD138 (also known as SYND1), which is expressed by multiple myeloma cells 152 . Because NK-92 cells are a tumour cell line infected with Epstein-Barr virus (EBV), they must be irradiated to prevent their proliferation before being adoptively transferred.…”

Targeting a Cancer-Specific Epitope of the Epidermal Growth Factor Receptor in Triple-Negative Breast Cancer

“…Because it was first identified as a family of possible oncogenes, the EGFR receptor family has been an attractive therapeutic target as these receptors are frequently upregulated in many cancers. Development of new HER2-targeted therapies, including antibody-delivered cytotoxins and chimeric antigenbased immune cell repertoires, has shown promise in both research and clinical settings (14,15,(30)(31)(32). However, while clinical targeting of EGFR function through small molecule inhibitors or antibody inhibition of EGFR signaling has shown some promise, successful long-term outcomes are rare because of compensatory kinase domain mutations or alternate receptor signaling and problems with toxicity to normal tissue (33)(34)(35)(36).…”