Intraepithelial Lymphocytes Suppress Intestinal Tumor Growth by Cell-to-Cell Contact via CD103/E-Cadherin Signal
Ryo Morikawa, Yasuhiro Nemoto, Yuki Yonemoto, Shohei Tanaka, Yuria Takei, Shigeru Oshima, Takashi Nagaishi, Kiichiro Tsuchiya, Kengo Nozaki, Tomohiro Mizutani, Tetsuya Nakamura, Mamoru Watanabe, Ryuichi Okamoto
Abstract
BACKGROUND & AIMS: The reason why small intestinal cancer is rarer than colorectal cancer is not clear. We hypothesized that intraepithelial lymphocytes (IELs), which are enriched in the small intestine, are the closest immune cells to epithelial cells, exclude tumor cells via cell-to-cell contact. METHODS: ) mice, which is a T-cell-reporter mouse with spontaneous intestinal tumors. We visualized the dynamics of IELs in the intestinal tumor microenvironment and the interaction between IELs and epithelial cells, and the roles of cell-to-cell contact in anti-intestinal tumor immunity using a novel in vivo live-imaging system and a novel in vitro co-culture system. RESULTS: mice and reduced the viability of them, which was cell-to-cell contact and CD103 dependent. CONCLUSIONS: The abundance of IELs in the small intestine may contribute to a low number of tumors, although this system may not work in the colon because of the sparseness of IELs. Strategies to increase the number of IELs in the colon or enhance cell-to-cell contact between IELs and epithelial cells may be effective for the prevention of intestinal tumors in patients with a high cancer risk.