Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Genetically engineered T cells expressing chimeric antigen receptors (CARs) have shown promising results particularly when targeting tumor associated antigens (TAAs) related to hematological malignancies. However, TAAs are usually expressed to some extend also on healthy tissues leading to on-target/off-tumor effects. To overcome this important safety issue along with improving targeting specificity and efficient killing of tumor escape variants, we adapted our Reverse CAR (RevCAR) system to follow an AND-gate Boolean logic. For that, Dual-RevCAR T cells were designed and armed with (I) a signaling (SIG) RevCAR, that includes the intracellular domain (ICD) of CD3 zeta; and (II) a costimulatory (COS) RevCAR, which contains a domain derived from CD28. Because the extracellular domains of both RevCARs are derived from the La/SS-B nuclear protein, Dual-RevCAR T cells will remain inactive until they encounter matching target modules (RevTMs). The bispecific antibody (bsAb)-like structure of the RevTMs allows their binding to RevCAR molecules and to specific antigens. However, only the simultaneous binding of RevTMs to SIG and COS RevCARs will promote the full activation of the Dual-RevCAR T cells. The epithelial cell adhesion molecule (EpCAM) and the carcinoembryonic antigen (CEA) have become appealing markers due to their overexpression in various solid tumor entities such as colorectal cancer, therefore representing promising target antigens for cancer immunotherapies following such a Dual Targeting CAR approach.

Having this in mind, the aim of this work was to assess the potential therapeutic application of the Dual-RevCAR system to target EpCAM and CEA following an AND-gating approach.