Multi-stromal organoid co-cultures model pancreatic cancer and pancreatitis epithelial cell-fibroblast heterogeneity

Malignant cell-fibroblast cross-talks modulate disease progression and therapy response of pancreatic ductal adenocarcinoma (PDAC). Our knowledge of the heterogeneous nature of PDAC cancer-associated fibroblasts (CAFs) has significantly increased over the last few years. Yet, whether CAFs in PDAC differ from fibroblasts in pancreatic inflammation remains poorly understood. Chronic pancreatitis - a prolonged inflammatory state of the pancreas - is a risk factor for PDAC and is characterised by abundant fibroblasts. Thus, dissecting pancreatic fibroblast and epithelial cell reprogramming in malignancy relative to inflammation could inform new preventative, diagnostic and therapeutic strategies for PDAC. Here, we studied how pancreatic malignancy and inflammation differently shape fibroblast heterogeneity and their crosstalk with epithelial cells. We analysed human samples and mouse models of pancreatitis and PDAC and leveraged new murine pancreatitis-derived epithelial organoids to establish pancreatitis and PDAC organoid/multi-stroma co-cultures comprising pancreatic stellate cells, fibroblasts and mesothelial cells. We demonstrate that a combination of in vitro and in vivo models better captures epithelial cell and fibroblast markers of human pancreatitis and PDAC compared to mouse models alone. Finally, we identify PDAC and pancreatitis epithelial cell-specific reprogramming of stromal cells of different origin, and we infer the contribution of these distinct stromal cell types to fibroblasts in PDAC and pancreatitis in vivo. Together, our study highlights different epithelial cell-fibroblast heterogeneity in PDAC and pancreatitis, and provides new platforms for the identification of markers and epithelial-stromal interdependencies of these diseases.