Engineering human ducts and acini from pluripotent stem cells to study cell type of origin and tumour evolution in pancreatic cancer

• Applicant: Professor Dr. Alexander Kleger
• Subject Area: Gastroenterology
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426789343

Human pluripotent stem cells harbour a unique and unlimited capacity for self-renewal and proliferation. Analysis and scientific exploitation of these cells has greatly improved our understanding of the pluripotency circuitry and subsequently occurring differentiation processes. Thereby, protocols have evolved allowing the virtually pure generation of a lot of cell types in our body, which in turn set the stage for future disease modelling in vitro. Pancreatic ductal adenocarcinoma (PDAC) is one of the most devastating diseases of the pancreas with a dismal prognosis despite intensive research efforts. Specifically, in PDAC patients the 5-year survival rate is only 4%. Current basic research in PDAC is mostly limited to mouse models underpinning the need for novel and innovative modelling tools. Previously, we have been successful in the formation of mixed ductal/acinar-like pancreatic organoids from human pluripotent stem cells that we applied for modelling pancreatic facets of cystic fibrosis and to screen for disease-rescuing drugs. However, the opportunity to separately induce either acinar or duct-like structures would unclose new opportunities particularly in cancer research. Within this grant proposal we plan to address these needs. Specifically, we will implement signals controlling embryonic cell fate decisions to efficiently yield the desired cell types through exclusion of alternate fates at lineage bifurcations. The developing pancreatic epithelium receives paracrine as well as cell-cell based input from the surrounding mesenchyme and vasculature in the developing pancreas. This niche-epithelium communication is further substantiated by extracellular matrix ascribing dynamic and static mechano-signalling to direct lineage segregation. Thus, we will also integrate this knowledge by matrix modification and specialized co-culture techniques to obtain the two mature exocrine pancreatic cell types, acinar and ductal cells. Xenotransplantation of human exocrine tissue into the pancreas and subsequent interconnection with the mouse host would launch a novel era of in vivo disease models. Our previous work has provided proof of concept but a systematic testing of different modifications either to the graft or the host to improve transplantation yield remains elusive. Therefore, in the second work programme this gap will be closed by graft modifications in terms of timing and matrix embedding and by host modifications due to injury. These modifications and systematic elaborations will help to improve engraftment of POs into the murine pancreatic host. Finally, we will set up in paralleling efforts an application platform for these novel cell types, namely genetically unmodified human acinar or ductal cells. Here, a human PSC based model for PDAC will address open questions regarding PDAC initiation, cell type of origin, different types of precursor lesions and PDAC dissemination during progression according to defined oncogenic events.

• DFG Programme: Research Grants