EInvestigating the interactions between regulatory T cells and cancer-associated fibroblasts and their role in lung cancer progression

Abstract The tumor microenvironment (TME) is a highly complex multicellular system and has been shown to play a fundamental role in dictating tumorigenesis. High expression of regulatory surface molecules, cytokines, and chemokines in fibroblast niches within lung tumor stroma, paired with their colocalization with tumor infiltrating lymphocytes (TILs), suggests that cancer-associated fibroblast (CAF) niches may alter the functional response of TILs and influence the anti-tumor immune response. Here, utilizing a transcriptomic approach, we have uncovered a distinct CAF population, which we term “iCAFs,” that is enriched for immunomodulatory gene signatures, T cell ligands, and chemoattractants. This population expresses a unique set of cell surface molecules that permit their identification and isolation from lung tumor tissue. Given the demonstrated importance of Tregs in suppressing anti-tumor immunity, we chose to evaluate how Tregs may be interacting with iCAFs within the TME of lung adenocarcinoma. We uncovered significant colocalization patterns of Foxp3 +Tregs with iCAF—a pattern which was found to be unique for Tregs when compared to conventional CD4 +Foxp3 −T cells. Moreover, the Treg to conventional CD4 +T cell ratio is significantly decreased in tumor tissue relative to normal adjacent tissue and healthy controls. Our analyses demonstrate that Tregs preferentially associate with iCAF populations within the tumor, leading us to hypothesize that interactions between Tregs and iCAFs may, in turn, influence Treg trafficking, phenotype and function within the TME. T32AI106711