T cells engineered against Dickkopf-1-A2 complex can be used to treat HLA-A2+ solid and hematologic cancers

Although chimeric antigen receptor (CAR)-T cells are promising effector cells to treat hematologic tumors, developing effective CAR-T cells for solid tumors remains challenging. Dickkopf-1 (DKK1) protein is widely expressed by human hematologic and solid tumors. Using the sequence of murine or humanized monoclonal antibody recognizing DKK1-A2 complexes (DKK1-P20 peptide in the context of HLA-A*0201) that are detected on all examined HLA-A2⁺ tumor samples but not normal tissues except tonsils, we generate DKK1-A2 CAR-T cells that specifically and effectively lyse HLA-A2- and DKK1-expressing tumor cells but not blood or bone marrow cells from HLA-A2⁺ healthy donors. In xenograft models of human myeloma, pancreatic, lung, and breast cancers and patient-derived xenograft of pancreatic cancer, DKK1-A2 but not CD19 CAR-T cells effectively control or eradicate established tumors without detectable toxicities in NSG or human DKK1 and HLA-A2-trangenic mice. This study indicates that DKK1-A2 CAR-T cells may be used to treat human cancers.