Characterisation of tissue-resident immune crosstalk in human pancreatic neoplasms and pancreatitis via single-cell transcriptomics

Background Pancreatic cancer is projected to become the second leading cause of cancer mortality in the late 2020s. The current 5-year pancreatic adenocarcinoma (PDAC) survival is under 7%.

Poor prognosis is linked to unmet medical needs: late diagnoses, lack of tumour markers, aggressive growth, early metastasis, resistance to treatment, and tumour microenvironment complexity. Pancreatic neuroendocrine tumours (pNET) are even less understood, both molecularly and clinically.

PDACs are believed to originate from microscopic precursor lesions in the exocrine pancreas and pNETs have recently been hypothesised to originate from ductal-acinar stem cells.

Previous epidemiological studies have established chronic pancreatitis as an important independent risk factor for pancreatic cancer. However, a molecular link is still missing in human studies.

As such, there is a critical need to better understand the exocrine pancreas, chronic pancreatitis, and pancreatic cancer, its cellular complexity, and its tumorigenesis to improve patient care.

Aims Our goals are to characterise primary and metastatic PDAC and non-PDAC pancreatic neoplasms, to uncover similarities with chronic pancreatitis (CP), and to describe the molecular and cellular characteristics of tissue resident immune cells (TRI)-crosstalk in CP and pancreatic neoplasms.

We have previously characterised specific TRI associated with the exocrine pancreas of mice, which participate in pancreatic inflammation.

Our preliminary results from 34,863 high-quality cells have revealed distinct stromal and ductal substates in inflammation or homeostasis, as well as a specific stromal subset with TRI-associated crosstalk signatures.

This work will translate and expand our finding to relevant human tissues such as PDACs, pNETs, and chronic pancreatitis biopsies.

Methods We designed a protocol to examine the exocrine pancreas by scRNA-seq and flow-cytometry in mice which overcomes inherent challenges associated with extremely high RNAase and protease concentrations in this organ.

Clinical collaborators will obtain biopsies and surgical resections from consenting patients at Addenbrooke’s Hospital in Cambridge. Samples will be stabilized and preserved in hypothermasol before enzymatic dissociation and FACS profiling and sorting.

Immune, epithelial, and stromal cells will be recovered and prepared for Chromium 10X single-cell RNAseq before Illumina NOVAseq sequencing.

How results of this research will be used Our data will resolve the exocrine pancreatic niche at a single-cell resolution, and describe the transcriptional signatures and regulatory mechanisms that are shared or unique among pancreatic neoplasms and pro-tumourigenic inflammation.

In addition, this work will reveal TRI-dependent immune-regulatory mechanisms in patients that will directly influence parallel pre-clinical studies into novel immunobiology and therapeutic approaches to target cancer development.