Why did we fund this project?
This award aims to validate in vitro murine pancreatic premalignant (PanIN) tissue organoids to replace the use of live mice in cancer progression studies from premalignancy to invasive cancer.
Research on pancreatic cancer predominantly uses mice, including genetically altered animals where tumours spontaneously develop. Developing these animal models requires extensive breeding programmes to generate the multiple mutations required to replicate disease. These models are classified as moderate under the UK’s Animals (Scientific Procedures) Act 1986 because of the level of suffering associated with manifestation of the disease. Late stage pancreatic cancer can also be modelled in vitro using organoids derived from either murine or human pancreatic cells. However, as patients are typically diagnosed with late-stage disease, it has not been possible to derive organoids from premalignant tissue. Dr Pedro Perez-Mancera has demonstrated organoids derived from murine PanIN tissue undergo malignant transformation when a tumour suppressor, Trp53, is inactivated. This enables pancreatic cancer progression to be modelled in vitro.
With NC3Rs funding, Pedro will build confidence in the PanIN organoid model and demonstrate its utility. He will downregulate tumour suppressor genes recurrently found inactivated in an in vivo mutagenesis screen and validate this data using the PanIN organoids. Pedro will then evaluate the use of PanIN organoids in therapeutic studies by treating with Gemcitabine, a chemotherapy drug commonly used in treating pancreatic cancer, to determine if the organoids predict a response to the drug. All the findings in the PanIN organoids will then be validated using resected human tissue samples.
Despite advances in our understanding of the molecular pathogenesis of pancreatic ductal adenocarcinoma (PDAC), the overall survival has remained unchanged over recent decades (~6%). There is an urgent and unmet need for understanding the molecular mechanisms driving the progression from a non-lethal preneoplastic stage (Pancreatic Intraepithelial Neoplasia, PanIN) to invasive and lethal PDAC, and to use this knowledge to identify novel options for PDAC therapy. Mouse models of pancreatic cancer have enabled a comprehensive investigation of the genetics and biology of this disease. However, in vivo approaches are costly and time-consuming, and crucially raise ethical concerns. To overcome these limitations, organoids derived from PDAC tissue have been established as a biologically relevant system to study advanced stages of pancreatic cancer, reducing the use of animals. However, the use of organoids derived from pancreatic preinvasive (PanIN) lesions to study the molecular basis of PanIN-to-PDAC progression is still largely unexplored. We have proved that PanIN organoids undergo neoplastic transformation after inactivating Trp53, a key tumour suppressor gene inactivated during PanIN-to-PDAC progression, validating this model to study the biology of pancreatic cancer progression, drastically reducing the number of mice required to perform experiments and ultimately replacing their use. Our scientific goal is to validate the use of PanIN organoids to study pancreatic cancer progression. Experimental data obtained in an in vivo transposon-mediated insertional mutagenesis screen will be validated in PanIN organoids by downregulating tumour suppressor gene candidates found recurrently inactivated in our in vivo screen. Then, we will assess the relevance of PanIN organoids to perform therapeutic studies and predict response to gemcitabine. Finally, we will confirm the clinical significance of PanIN organoids by validating our findings in resected human PDAC specimens.