scRNA-seq analysis of mouse tumor-infiltrating immune cells

Cancer immuno-surveillance and response to checkpoint blockade therapy can be affected by multiple environmental factors, including nutrition. However, the direct effects of individual nutrients on anti-tumoral immune responses remain poorly understood. Here we addressed the impact of dietary ligands of Aryl Hydrocarbon receptor (AhR), a transcription factor activated by indoles and tryptophan catabolites generated through food digestion and microbiota metabolism. To this aim, we analyzed pre-clinical tumor models in mice fed on a diet naturally poor in AhR ligands, or the same diet enriched for Indole-3-carbinol, a phytonutrient cleaved by stomach enzymes into AhR agonists. Mice were fed with a diet poor in AhR ligands (AhR-poor diet) or the same diet supplemented in indole-3-carbinaol (I3C diet). Mice were inoculated with MCA-101-OVA tumor cells. Tumor infiltrating cells were isolated as CD45+CD11b+ or CD45+TCRb+ and analyzed by scRNA-seq.