Single-cell epigenomic analysis reveals an important role of the receptor kinase Ror2 in the erosion of cellular identity during pancreatic carcinogenesis
Recommended Citation
Benitz S, Nasser M, Steep A, Loveless I, Wen H, Long D, Davis ET, Rempinski D, Louw M, Moore J, Steele N, Mahajan U, Regel I, Bednar F, Crawford H. Single-cell epigenomic analysis reveals an important role of the receptor kinase Ror2 in the erosion of cellular identity during pancreatic carcinogenesis. Pancreatology 2023; 23:e126.
Document Type
Conference Proceeding
Publication Date
11-5-2023
Publication Title
Pancreatology
Abstract
Abstract Background: The major driver for pancreatic ductal adenocarcinoma (PDAC) is oncogenic KRAS. However, adult acinar cells, a probable origin of PDAC, are largely refractory to KrasG12D-mediated oncogenic transformation. With the concomitant loss of transcription factors that regulate acinar cell differentiation, such as Pdx1 (Pancreatic and Duodenal Homeobox 1), acinar cells undergo a rapid cell identity switch, known as acinar-to-ductal metaplasia (ADM). How loss of cell identity cooperates with oncogenic Kras to induce pancreatic transformation is largely unclear. Methods: To elucidate mechanisms responsible for the accelerated cellular reprogramming in KrasG12D;Pdx1f/f animals, single-cell ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) from frozen pancreatic bulk tissue was performed. Chromatin accessibility states were captured at early stages of carcinogenesis and correlated to RNA-seq data. Differentially regulated genes were validated by multiplex RNAscope and immunohistochemistry staining and functionally studied in pancreatic cancer cell lines. Results: Single-cell ATAC-seq proved a powerful tool for defining cell-type identity, cellular reprogramming and target genes in early metaplastic transformation of pancreatic tissue. Notably, acinar cells of KrasG12D;Pdx1f/f animals as well as a proportion of metaplastic lesions in both, KrasG12D and KrasG12D;Pdx1f/f mice, showed elevated accessibility and expression of the Ror2 gene. As a receptor tyrosine kinase, Ror2 controls essential signalling pathways, such as Ras-MAPK signalling. By analysing Ror2 knockout mice, we found that the receptor kinase regulates the identity of metaplastic epithelia. Moreover, Ror2 expression highly correlates with the more aggressive basal-like subtype in mouse and human PDAC. Overexpression of ROR2 in pancreatic cancer cell lines with a classical differentiation induced epithelial-to-mesenchymal transition, characterised by the downregulation of multiple epithelial markers and upregulation of mesenchymal genes. In addition, ROR2-overexpressing cells proliferated much more rapidly, while knockout of ROR2 in pancreatic cancer cells significantly decreased cell proliferation. Conclusion: Our in-depth sequencing data revealed that expression of KrasG12D with the concomitant loss of Pdx1 leads to vast alterations of acinar cell identity. We identified the receptor kinase Ror2 as a regulator of pancreatic cancer initiation and driver of pancreatic cancer cell aggressiveness.
Medical Subject Headings
Hematology
PubMed ID
Not assigned.
Volume
23
First Page
e126
