Abstract 1600: Interception of pro-tumorigenic glycan signaling in pancreatic cancer

Abstract Pancreatic cancer is a deadly malignancy. We have setup a pipeline to interrogate cancer cell intrinsic and extrinsic mechanisms contributing to treatment response. Using a combination of mouse and human organoids models together with in vivo investigation, we have systematically dissected key signaling hubs driving pro-tumorigenic cancer cell intrinsic features as well as remodeling of the tumor microenvironment (TME). We found that the glycan epitope, CA19-9, drives pancreatic inflammation, cancer, and metastasis. CA19-9 drives pro-tumorigenic intrinsic features in part through CA19-9 modification of the secreted glycoprotein Fibulin 3. We have also discovered direct and indirect mechanisms through which CA19-9 causes remodeling of the TME. Specifically, CA19-9 elevation causes expansion of all cancer associated fibroblast (CAF) subtypes, including an increase in antigen presenting CAFs and resulting increase in regulatory T cells. Further, there are dramatic increases in tumor associated macrophages (TAMs) derived from both inflammatory monocytes as well as tissue resident macrophages. To delineate the mechanisms by which these TME changes are mediated, we use novel co-culture model incorporating macrophages, organoids, and fibroblasts (MOrF). Blocking CA19-9 signaling in vitro and in vivo reverses these TME alterations. These changes to the TME are mediated through indirect effectors as well as previously unknown CA19-9 modified proteins. Overall, we elucidate previously unexplored mechanisms driving pancreatic tumorigenesis while also uncovered vulnerabilities for therapeutic exploitation. Citation Format: Jasper Hsu, Hyemin Song, Kristina Peck, Chelsea Bottomley, McKenna Stamp, Shira Okhovat, Dannielle D. Engle. Interception of pro-tumorigenic glycan signaling in pancreatic cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 1600.