Abstract A054: Collagen fiber architecture modulates PDAC cell and organoid phenotype
Authors: Doyle Ciara L , Xavier Shanu , Lu Jarren Y.S , Fallon Leah , Sarkar Anwesha , Baguyo Jan J , Gars Maela , Thorpe Stephen D 
Published: September 2024

Abstract
Introduction Collagen plays a significant role in the development of pancreatic ductal adenocarcinoma (PDAC). Disease progression is mediated by a dense collagenous stroma, which acts as a barrier to drug delivery and immune cell access. Current in vitro models do not well represent the collagenous stroma seen in PDAC. The aim of this study is to develop a fibrillar collagen-based hydrogel system which mimics the tumour microenvironment seen in PDAC and assess cell-mediated collagen remodeling. Methods Metastatic SUIT2-007 pancreatic cancer cells, non-metastatic BxPC3 pancreatic cancer cells, and human pancreatic stellate cells (hPSCs) were encapsulated in bovine type I collagen gels of various concentrations. KPC mouse derived tumour organoids were also encapsulated in bovine type I collagen gels of 2 mg/ml and 6 mg/ml concentrations, basement membrane extract (BME), and a combination of BME and collagen gel. Cell viability and proliferation was assessed using Live/Dead imaging and CellTitre-Glo 3D respectively. Cell mediated collagen remodeling was assessed via monitoring of gel contraction on the mm scale, and confocal reflectance microscopy on the cellular scale. Collagen contraction around cells was assessed by measuring the pixel intensity of collagen fibrils within the vicinity of the cell. Cell phenotype was assessed via immunofluorescent staining and qPCR. Results Collagen concentration alters the hydrogel structure and stiffness, with 3 mg/ml collagen resulting in straighter, shorter and thicker fibrils. Metastatic SUIT-007 cells contracted collagen gels more rapidly than non-metastatic BxPC3 cells, with both achieving similar contraction by day 7. SUIT2-007 cells remodel and align soft 1 mg/ml gels while 3 mg/ml gels proved to be sufficiently stiff to resist remodeling. Cellular collagen association was increased in more elongated SUIT-007 cells than in BxPC3 cells. Organoid proliferation varies with hydrogel collagen concentration. Conclusion Metastatic SUIT2-007 cells were able to remodel collagen more rapidly and to a greater extent than non-metastatic BxPC3 cells. Collagen supports an invasive organoid phenotype. Collagen gels combined with confocal reflectance microscopy provide a platform for the quantitative assessment of cell-matrix interactions in PDAC. Acknowledgements This project was funded by a Medical Traineeship from UCD School of Medicine, and summer student scholarships from Irish Cancer Society and Breakthrough Cancer Research. We acknowledge the Conway Imaging Core Facility for assistance with microscopy.
Citation Format: Ciara L Doyle, Shanu Xavier, Jarren Y.S Lu, Leah Fallon, Anwesha Sarkar, Jan J Baguyo, Maela Gars, Stephen D Thorpe. Collagen fiber architecture modulates PDAC cell and organoid phenotype [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 Suppl_2):Abstract nr A054.