Exploring the therapeutical potential of DOT cells in colon cancer

Abstract

Gamma delta T cells hold great promise for cancer immunotherapy, as they display broad tumor reactivity, and recognize tumor cells independently of both mutational load and human leukocyte antigen (HLA)-mediated antigen presentation. Our laboratory has established a clinical-grade protocol allowing robust expansion and differentiation of anti-tumor V delta 1+ T cells (termed Delta One T/ DOT cells), which thereby acquire high expression of activating NK receptors. These cells effectively controlled tumor progression in pre-clinical models of leukemia and are currently being tested in a phase I clinical trial in acute myeloid leukemia. In this project we aim to provide the proof-of-concept for the use of DOT cells in solid tumors, particularly colon cancer, whose low mutational burden renders current immunotherapy markedly ineffective. We will investigate the role of key NK receptors, DNAM-1 and NKG2D and their ligands, but also of the TCR-dependent regulators of gamma delta T cells, butyrophilins (BTN) and butyrophilin-like (BTNL) proteins, on DOT-cell recognition of human colon cancer-derived organoids and primary samples. We will generate knockout tumor or DOT cells for the relevant candidates, to perform cytotoxicity assays, which will reveal molecular determinants of tumor cell recognition by DOT cells and may bear predictive/ therapeutic value. Furthermore, we will address three roadblocks that DOT cells may encounter in the solid TME (tumor microenvironment): immunosuppression, glucose restriction and hypoxia. We will screen for the effect of different immunosuppressive subsets and document the impact of glucose deprivation and hypoxia, on DOT-cell effector functions. Finally, we will incubate DOT cells with different drugs during the expansion protocol to generate a more robust product able to counteract the inhibitions imposed by these hurdles. Altogether, we expect to generate translational knowledge that will pave the way for DOT-cell clinical application in colon cancer and other solid malignancies, especially those with low mutational burden, thus overcoming the limitations of current immunotherapy. (AU)