Characterization of the aryl hydrocarbon receptor as a potential candidate to improve cancer T cell therapies

T cell-based cancer therapies efficacy can be limited by the tumor microenvironment which can lead to T cell dysfunction. Multiple studies, particularly in murine models, have demonstrated the capacity of the aryl hydrocarbon receptor (AhR) to negatively regulate antitumor T cell functions. AhR is a cytoplasmic receptor and transcription factor that was originally identified as a xenobiotic sensor, but has since been shown to play a significant role in the gene regulation of various immune cells, including T cells. Given the insights from murine studies, AhR emerges as a promising candidate to invalidate for optimizing T cell-based cancer therapies. However, the lack of studies on the role of AhR in human T cells underscores the need for comprehensive characterization of AhR expressing T cells. This study aims to investigate the regulatory mechanisms of AhR in human T cell biology to better understand its impact on reducing antitumor immune responses. By using the CRISPR-Cas method, knockout was performed on human T cells in order to characterize Ahr knocked-out T cells using an in vitro chronic stimulation model. Engineered T cells exhibited enhanced effector- and memory-like profiles and expressed reduced amount of CD39 and TIGIT. Ahr knockout enhanced human CAR-T cells’ functionality and persistence upon tumor chronic stimulation. Collectively, these results highlight the role of AhR in human CAR-T cells efficiency. To investigate the role of the aryl hydrocarbon receptor (AhR) on T cells' biology, we knocked-out Ahr by CRISPR-Cas9. We performed gene expression profiling analysis using data obtained from RNA-Seq of 3 donors at two different timepoints (either restimulated once or four times using dynabeads) in presence of AhR' ligand.