Specific growth inhibition of ErbB2-expressing human breast cancer cells by genetically modified NK-92 cells

The natural killer cell line NK-92 shows great cytotoxicity against various types of cancer. Several types of solid tumor cells, however, can effectively resist NK-mediated lysis by interaction of major histocompatibility complex (MHC) molecules with NK cell inhibitory receptors. To generate a eukaryotic expression vector encoding chimeric antigen receptor scFv anti-erbB2-CD28-ζ and to investigate the expression and action of this chimeric antigen receptor in cancer cells both in vitro and in vivo, NK-92 cells were genetically modified with an scFv anti-erbB2-CD28-ζ chimeric receptor by optimized electroporation using the Amaxa Nucleofector system. The expression of the chimeric receptor was evaluated by RT-PCR and immunofluorescence. The ability of the genetically modified NK-92 cells to induce cell death in tumor targets was assessed in vitro and in vivo. The transduced NK-92-anti-erbB2 scFv-CD28-ζ cells expressing high levels of the fusion protein on the cell surface were analyzed by fluorescence-activated cell-sorting (FACS) analysis. These cells specifically enhanced the cell death of the erbB2-expressing human breast cancer cell lines MDA-MB-453 and SKBr3. Furthermore, adoptive transfer of genetically modified NK-92 cells specifically reduced tumor size and lung metastasis of nude mice bearing established MDA-MB-453 cells, and significantly enhanced the survival period of these mice. The genetically modified NK-92 cells significantly enhanced the killing of erbB2-expressing cancer and may be a novel therapeutic strategy for erbB2-expressing cancer cells.