Poster Presentation 37th Lorne Cancer Conference 2025

Unravelling epithelial cell heterogeneity in the distal oesophagus (#207)

Cal McCrimmon 1 2 , Wayne Phillips 1 2 , Nicholas Clemons 1 2
  1. Division of Cancer Research, Peter MacCallum Cancer Centre, Parkville, Victoria, Australia
  2. Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia

Oesophageal adenocarcinoma (OAC) most often occurs in patients with a history of gastric reflux and evolves from a preneoplastic lesion called Barrett’s metaplasia (1). Although there are well defined risk factors for OAC, 50% of patients are diagnosed too late for curative intent treatment (2). Early detection and risk stratification strategies are ineffective owing to very little being known about the early pathogenesis of the disease. An existing body of research indicates that metaplasia in the epithelium arises by non-genetic transformation of a yet to be identified progenitor cell in the distal oesophagus (3-6). Identifying this cell of origin will help to uncover biological mechanisms that drive the initial stages of metaplasia. This will ultimately lead to more effective detection and treatment modalities and thus better patient outcomes.

Our understanding of epithelial cell types within the human oesophagus is severely limited by the low-dimension protein marker-based methods historically used to identify them. We reanalysed published single nuclei sequencing data to resolve complete transcriptomic profiles of all major epithelial lineages within the oesophagus and identified expression signatures and markers of key subtypes which were validated using multiplex immunofluorescence and RNAScope. We identified SLC7A1, COL7A1 and SOX6 as basal cell markers, and found distinct subpopulations of LGR6+ quiescent basal cells highly expressing cell adhesion genes, and IL1R2+ basal cells expressing receptor tyrosine kinase signalling genes.  Finally, we found that ERBB4 marks cells within the submucosal glands whilst SLC12A2 and PROM1 specifically mark the secretory and ductal cells respectively. This information will enable us to isolate specific epithelial cell subtypes from fresh human oesophagus by FACS, and assay their capacity for regeneration and differentiation in organoid cultures. Additionally, we are developing novel strategies to maximise cell yield and viability during digestion to capture clonal structures in small tissue pieces for single cell sequencing and in situ lineage tracing. This will enable us to elucidate clonal relationships between cell types and identify progenitor cells and lineage trajectories in the oesophagus.

 

 

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