Background：Pancreatic ductal adenocarcinoma (PDAC) is increasing in incidence and is now the third leading cause of cancer-related death in Australia, with a 5-year survival rate below 15%. The tumour microenvironment (TME) plays a key role in therapeutic resistance. However, it is often overlooked in drug development due to the lack of physiologically relevant in vitro models. We are implementing a more physiologically relevant 3D PDAC organoid model that incorporates both cancer-associated fibroblast (CAF) heterogeneity and the immune microenvironment, overcoming limitations of standard patient-derived organoids (PDOs) which have no TME. Recent studies show that CD105 can distinguish two functional CAF subtypes: tumour-promoting CD105⁺ CAFs and immune-enabling, tumour-suppressive CD105⁻ CAFs. Therefore, capturing CAF diversity, including CD105-based subtypes, is essential to understand tumour–TME interactions and improve therapeutic strategies.
Methods: We co-cultured PDOs with induced pluripotent stem cell (iPSC)-derived endothelial and mesenchymal cells as well as immune cells, in an air-liquid interface (ALI) system to develop PDAC-TME organoids. Immunofluorescence and flow cytometry were used to identify different cellular components. These organoids were then used to screen current and emerging PDAC treatments and metabolic-targeting agents.
Results: We established two types of PDAC-TME organoids that exhibit ductal architectures closely resembling the pathological features of PDAC. iPSC-derived endothelial cells successfully integrated into the PDAC-TME organoids and self-organized into vascular-like structures. Importantly, CAF heterogeneity, including the recently discovered tumour-promoting (CD105⁺) and tumour-suppressive (CD105⁻) CAF populations were detected in the PDAC-TME organoids. Furthermore, oncogenic CD105⁺ CAFs were found to be more abundant, consistent with patient tumour profiles. Drug testing revealed differential effects across CAF subpopulations and highlighted the influence of CAF and immune cell context on therapeutic sensitivity.
Conclusion: This PDAC-TME organoid platform provides a physiologically relevant and scalable system to investigate CAF-driven mechanisms and evaluate therapies targeting the TME. Further refinement and expansion of these allogeneic models using patient-derived components will be essential for enhancing physiological relevance and establishing a robust platform for preclinical therapeutic testing.