Abstract A035: 3D High-Density Collagen I Improves the Modeling of Aggressive Pancreatic Cancer

Abstract Background: Fibrillar collagen type I constitutes the majority of the extracellular matrix in pancreatic ductal adenocarcinoma (PDAC), yet most in vivo murine models involve the use of basement membrane extracts, which instead contain collagen type IV, as matrices to embed PDAC cells. Type I collagen in the PDAC tumor microenvironment has been associated with worse prognosis. Our hypothesis is that PDAC cells grown in 3D high-density collagen I (HDC) gels behave more aggressively compared to the same cells grown using conventional basement membrane matrix (BMM). Methods: The KPC1199 2D cell line was previously generated from a tumor-bearing male KPC mouse. KPC1199 cells were cultured in vitro in HDC or BMM for one week. Orthotopic tumors were established by embedding KPC1199 cells in HDC (N=10) or BMM (N=10) in the pancreatic tail of syngeneic C57BL/6J mice via laparotomy. Half of the tumors were collected five weeks after tumor implantation, and the other half utilized for a survival study. Collagen was imaged by second harmonic generation (SHG) microscopy. Results: In vitro imaging of single KPC1199 cells grown in HDC revealed an aggressive phenotype with clonal network-like structures compared to a spheroidal, non-aggressive phenotype for cells grown in BMM over the course of seven days. SHG imaging confirmed consistent formation and organization of collagen in HDC tumors but minimal to faint collagen formation in BMM tumors. Gross examination of HDC mice showed 60% with visible liver metastasis compared with none in the BMM mice. In the survival study, the entire HDC group died before the BMM group (p-value 0. 01). Conclusions: Our pilot study is the first, to our knowledge, to successfully generate orthotopic PDAC tumors using 3D high-density collagen I in a mouse model. KPC1199 cells embedded in HDC showed an aggressive phenotype in vitro, and resultant tumors demonstrated more robust collagen organization compared to the same cells grown in the BMM substrate. This aggressive phenotype translated to visible liver metastasis within five weeks in the HDC mice and prior to death from primary tumor burden. This is not typical for most KPC-derived cell lines but is typical for human PDAC patients. Our preliminary findings support the use of HDC as an alternative substrate for better modeling of this aggressive cancer. Citation Format: Kim Nguyen-Ta, Sural Ranamukhaarachchi, Jeffrey Turner, Utsav Joshi, Himangshu Sonowal, Jorge de la Torre Medina, Herve Tiriac, Stephanie Fraley, Rebekah White. 3D High-Density Collagen I Improves the Modeling of Aggressive Pancreatic Cancer abstract. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84 (17 Suppl₂): Abstract nr A035.