Sonia Ghilas, Dinesh Raghu, Kelly Tran, Yang Liao, Bhupinder Pal, Shoukat Sterle, Christine Dijkstra, Marina Yakou, Pavitha Parathan, John Mariadason, Matthias Ernst, Andreas Behren, Grant Drummond, Wei Shi, and Lisa A. Mielke
Homeostasis in the gut is achieved by impeccable functioning of tissue resident immune cells that reside and closely interact with the epithelium. The tissue resident immune cells of the intestinal epithelium are predominantly lymphocytes, known as intraepithelial lymphocytes (IELs) and mainly consist of TCRαβ T cells and TCRgd T cells. These IELs are well known to sense microbes, nutrients, and cellular stress but their role in intestinal cancer progression has been controversial. On one hand, gd Τ cells are the primary source of IL-17, an important proinflammatory cytokine that aid in colorectal cancer (CRC) progression. On the other hand, mice lacking gd Τ cells have been showed to have an increased risk of developing carcinogen-induced CRC. Here we used two different mouse model of colon cancer to investigate the role of gd T IELs in colon tumor growth. We showed that in both orthotopic implantation of cancer cells in the colon, and inflammation-driven colon cancer models, gd T cells are essentials to limit tumor growth. Indeed, mice lacking gd T cells had increased tumor incidence with high-grade adenomas compared to control mice. We also performed gene expression analysis of the adenomas in control mice and in mice lacking gd T cells. They revealed distinct transcription profiles with CRC-associated gene expression profile, including inflammatory genes and epithelial to mesenchymal transition genes, particularly enriched in adenomas from gd T cell deficient mice. Moreover, using human tissue microarrays, we investigated whether the presence of gd T cells in tumors of patients with advanced CRC could be used to predict disease outcomes. We revealed that patient disease-free survival was improved if gd T cells could be detected within tumors. Therefore, we showed that gd T cells are primordial in limiting colorectal cancer progression in both mice and humans. Citation Format: Sonia Ghilas, Dinesh Raghu, Kelly Tran, Yang Liao, Bhupinder Pal, Shoukat Sterle, Christine Dijkstra, Marina Yakou, Pavitha Parathan, John Mariadason, Matthias Ernst, Andreas Behren, Grant Drummond, Wei Shi, Lisa A. Mielke. Intestinal intraepithelial T cells limit colorectal cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr PR007.