Experimental Treatment of Colorectal Cancer in Mice with Human T Cells Electroporated with NKG2D RNA CAR

Abstract

<b>Aim:</b> Peritoneal metastasis is often present in end-stage neoplastic diseases, including recurrent colorectal cancer and is associated with decreased overall survival. Novel methods are needed. <b>Materials & methods:</b> We constructed first-, second- and third-generation chimeric antigen receptors (CARs) specific for NKG2D ligands and modified human T cells with mRNA electroporation. <b>Results:</b> NKG2D CAR expression was detectable for at least 6 days postelectroporation and mediated efficient cytotoxicity against NKG2DL+ tumor cells, but not NKG2DL-cells. Multiple infusions of the first-generation CAR-T cells into immunodeficient mice bearing established peritoneal colorectal xenografts led to significantly reduced tumor burden. <b>Conclusion:</b> mRNA CAR is an economical way to test new CARs and potentiates controlling on-target/off-tumor toxicity and cytokine storms. The use of NKG2D RNA CARs to treat colorectal peritoneal metastasis warrants further investigation.