Abstract 3937: Investigating the role of fibulin 3 in pancreatic tumorigenesis

Abstract Pancreatic ductal adenocarcinoma (PDA) is a highly lethal malignancy with a five-year survival rate of less than 11%, making it one of the deadliest cancers. Notably, 95% of PDA cases exhibit KRAS mutations, contributing to highly dysregulated cell signaling networks. Despite extensive research into the interplay of various oncogenic pathways in pancreatic tumorigenesis, targeted therapies against these signaling networks have displayed modest efficacy, with most patients rapidly developing therapeutic resistance. Recent studies highlight the significance of the carbohydrate antigen 19-9 (CA19-9) as a functional biomarker linked to disease progression and resistance. However, understanding the detailed functions of CA19-9-modified proteins in PDA has been limited due to the lack of adequate models for synthesizing CA19-9. To address this challenge, we have developed unique mouse and 3D organoid culture models capable of producing CA19-9. CA19-9 elevation in mice with KRAS-mutations results in an aggressive PDA phenotype through increased tumor proliferation and microenvironment (TME) remodeling. Furthermore, our research has identified Fibulin 3 (FBLN3), an extracellular matrix glycoprotein, as a secreted, CA19-9-modified protein that stimulates tumorigenesis. In this study, we found that FBLN3 not only facilitates tumor proliferation but also drives epithelial-mesenchymal transition (EMT) and promotes STAT3 pathways activation in the CA19-9pos, KRAS-mutant PDA organoids. Additionally, in both CA19-9pos, KRAS-mutant PDA mouse models and human PDA, FBLN3 is expressed by cancer-associated fibroblasts (CAFs), suggesting its role in TME remodeling. These findings have significant implications for providing novel insights into PDA biology and paracrine signaling mechanisms, identifying FBLN3 as a potential therapeutic target for the improved treatment of this devastating disease. Citation Format: Hyemin Song, Jasper Hsu, Xiaoxue Lin, Satoshi Ogawa, Vasiliki Pantazopoulou, Kristina Peck, Chelsea Bottomley, Shira Okhovat, McKenna Stamp, Kassidy Curtis, Jeffrey D. Esko, Dannielle D. Engle. Investigating the role of fibulin 3 in pancreatic tumorigenesis 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 3937.