Characterization of a novel type NK cell line KHYG-1 carrying EGFRvIII-specific CAR in glioblastoma cells

Abstract

Abstract Background Natural killer (NK) cells are considered potential antitumor effector cells. The aim of this study was to establish a novel type of a chimeric antigen receptor (CAR)-NK cell line (CAR-KHYG-1) specific for epidermal growth factor receptor variant III (EGFRvIII)-expressing glioblastoma (GBM) cells and investigate the antitumor effects of EGFRvIII-specific-CAR-expressing KHYG-1 (EvCAR-KHYG-1) in vitro and in vivo. Materials and Methods EvCAR-KHYG-1 was established by lentiviral-based transduction of the EvCAR gene and magnetic bead-based purification of EvCAR-expressing NK cells. The antitumor effects of EvCAR-KHYG-1 were evaluated using growth inhibition and apoptosis detection assays on GBM cell lines (EGFRvIII-expressing and non-expressing U87MG glioma cells). Cytokine production was determined by cytometric beads array. In vivo xenograft assays were performed in NOG mice subcutaneously implanted with EGFRvIII-expressing U87MG (Ev-U87MG). Results EvCAR-KHYG-1 inhibited GBM cell-growth via apoptosis in an EGFRvIII-expression specific manner in vitro. In addition, EvCAR-KHYG-1 produced IL-2, INF-γ and TNF-α on Ev-U87MG cells. In vivo xenograft assays showed that EvCAR-KHYG-1 did not decrease the volume of subcutaneous tumors but inhibited the occupancy of cancer cells in the subcutaneous tumor. Discussion EvCAR-KHYG-1 enhanced antitumor effects and produced Th1-type cytokines on EGFRvIII-expressing GBM cells, but did not inhibit progression of subcutaneous GBM cell-derived tumors to induce a pseudo progression pathological phenotype. Conclusion A novel type CAR-NK cell line was established. In vivo experiments are required to determine ways it can be used to inhibit tumor progression.