Abstract IA025: Stem and metaplastic cell states and their influences on the tumor immune microenvironment in colonic pre-cancerous lesions


 The immune microenvironment is critical to colorectal cancer (CRC) pathogenesis, regarding both prognosis and therapeutic responses. While much work has been done to characterize tumor microenvironments, less is known about those environments are established following transformation of epithelial cells. We hypothesize that mapping routes towards CRCs, from normal human colonic tissues and precursor polyps, will uncover additional mechanisms that define the CRC cellular landscape and identify targets with diagnostic or therapeutic utility. Here, we present a comparative atlas of the two most common colorectal precursor lesions, conventional adenomas and serrated polyps, and their resulting CRC counterparts using single-cell transcriptomics and multiplex imaging across two cohorts of human participants. Integrative analysis reveals adenomas arise from dysregulated WNT-driven expansion of stem cells, while serrated polyps are depleted of stem cell populations and are derived from differentiated cells transitioning through a pyloric metaplasia program. Mucosal damage associated with metaplasia is coupled to a cytotoxic immune microenvironment that precedes hypermutation. Mouse and organoid experiments validate the importance of the differentiation states of colonic tumor cells in driving cytotoxic immunity partly through increased expression of antigen-presentation machinery. These data provide constitute a rich resource into malignant progression of colorectal polyps and their microenvironments, serving as a framework for precision surveillance and prevention of CRC.
 Citation Format: Ken S. Lau. Stem and metaplastic cell states and their influences on the tumor immune microenvironment in colonic pre-cancerous lesions [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 IA025.