ELIMINATION OF EGFR-OVEREXPRESSING CANCER CELLS BY CD32 CHIMERIC RECEPTOR T CELLS IN COMBINATION WITH CETUXIMAB OR PANITUMUMAB

Cetuximab and panitumumab bind the human epidermal growth factor receptor (EGFR). While the chimeric cetuximab (IgG1) triggers antibody-dependent-cellular-cytotoxicity (ADCC) of EGFR positive target cells, panitumumab (a human IgG2) does not. The inability of panitumumab to trigger ADCC reflects a poor binding affinity of human IgG2 Fc for the Fc{gamma}RIII (CD16) on NK cells. However, both human IgG1 and IgG2 bind the Fc{gamma}RII (CD32) to a similar extent. Here, we have compared the ability of T cells, engineered with a novel low-affinity CD32131R -chimeric receptor (CR), and those engineered with the low-affinity CD16158F-CR T cells in eliminating EGFR positive epithelial cancer cells (ECCs) in combination with cetuximab or panitumumab. Following T cell transduction, the percentage of CD32131R-CR T cells was (74{+/-}10) significantly higher than that of CD16158F-CR T cells (46{+/-}15). Only CD32131R-CR T cells bound panitumumab. CD32131R-CR T cells combined with the mAb 8.26 (anti-CD32) and CD16158F-CR T cells combined with the mAb 3g8 (anti-CD16) eliminated colorectal carcinoma (CRC), HCT116Fc{gamma}R+ cells, in a reverse ADCC assay in vitro. Cross-linking of CD32131R-CR on T cells by cetuximab or panitumumab and CD16158F-CR T cells by cetuximab induced elimination of triple negative breast cancer (TNBC) MDA-MB-468 cells, and secretion of IFN gamma (IFN{gamma}) and tumor necrosis factor alpha (TNF). Neither cetuximab nor panitumumab induced Fc{gamma}-CR T anti-tumor activity against KRAS-mutated HCT116, non-small-cell-lung-cancer, A549 and TNBC, MDA-MB-231 cells. ADCC of Fc{gamma}-CR T cells was significantly associated with the over-expression of EGFR on ECCs. In conclusion, CD32131R-CR T cells are efficiently redirected by cetuximab or panitumumab against BC cells overexpressing EGFR.\n\nArticle categoryTumor Immunology and Microenvironment\n\nNovelty and ImpactMonoclonal antibody-redirected Fc{gamma}-CR T cell immunotherapy represents a promising approach in the fight against cancer. Here, we expand the application of this methodology to TNBC overexpressing the EGFR utilizing a novel CD32A131R-CR in combination with anti-EGFR mAbs. Our study supports the use of CD32A131R-CR T cells combined with panitumumab or cetuximab for targeting TNBC cells overexpressing the EGFR. Our results may be utilized as a platform for the rational design of therapies targeting TNBC overexpressing EGFR.