Cellular heterogeneity during mouse pancreatic ductal adenocarcinoma progression at single-cell resolution.

Abstract

e15739 Background: Pancreatic ductal adenocarcinoma (PDA) is a major cause of cancer-related death with limited therapeutic options available. This highlights the need for improved understanding of the biology of PDA progression. The progression of PDA is a highly complex and dynamic process featuring changes in cancer cells and stromal cells; however, a comprehensive characterization of PDA cancer cell and stromal cell heterogeneity during disease progression is lacking. In this study, we aimed to profile cell populations and understand their phenotypic changes during PDA progression. Methods: We employed single-cell RNA sequencing technology to agnostically profile cell heterogeneity during different stages of PDA progression in genetically engineered mouse models. Results: Our data indicate that an epithelial-to-mesenchymal transition of cancer cells accompanies tumor progression. We also found distinct populations of macrophages with increasing inflammatory features during PDA progression. In addition, we noted the existence of three distinct molecular subtypes of fibroblasts in the normal mouse pancreas, which ultimately gave rise to two distinct populations of fibroblasts in advanced PDA, supporting recent reports on intratumoral fibroblast heterogeneity. Our data also suggest that cancer cells and fibroblasts are dynamically regulated by epigenetic mechanisms. Conclusions: This study systematically outlines the landscape of cellular heterogeneity during the progression of PDA. It strongly improves our understanding of the PDA biology and has the potential to aid in the development of therapeutic strategies against specific cell populations of the disease.

Integrated transcriptional analysis reveals macrophage heterogeneity and tumor-macrophage interactions in the progression of pancreatic ductal adenocarcinoma

“…Single-cell RNA sequencing (scRNA-seq) enables the characterization of cell diversity and heterogeneous phenotypic states of macrophage compartments in more detail, which has been applied recently for primary pancreatic cancers and mouse PDAC models [13][14][15]. However, the functional heterogeneity of different subpopulations, cellular reprogramming and phenotypic trajectories of macrophages during PDAC progression remain poorly characterized.…”

Targeting TGF βR2‐mutant tumors exposes vulnerabilities to stromal TGF β blockade in pancreatic cancer

“…Furthermore, we found that CAFs are a major source of TGFb-induced IL-6 expression. Several recent studies including ours demonstrate the existence of fibroblast heterogeneity within PDA (Ohlund et al, 2017;Bernard et al, 2019;Elyada et al, 2019;Hosein et al, 2019). Two major populations of CAFs have been identified, one is characterized by an inflammatory feature, while the other has been known as myofibroblast.…”

“…Recently, several studies, including ours, suggest the existence of two different subtypes of CAFs in PDA (Ohlund et al, 2017;Bernard et al, 2019;Elyada et al, 2019;Hosein et al, 2019). Of the two CAF populations, one appears to be inflammatory, characterized by PDGFRa expression and the secretion of a variety of inflammatory chemokines.…”

“…CAFs are the major source of IL-6 regulated by TGFb in PDA To identify the stromal cell type that secretes IL-6 in a TGFb-dependent manner, we performed single-cell RNA sequencing (scRNAseq) using whole tissue samples derived from normal mouse pancreas, early PDA, and late PDA from KIC mice (Hosein et al, 2019). We found that TGFbR1/R2 was mainly expressed by fibroblasts in the normal pancreas as well as early PDA (Fig 2A).…”

“…Data analysis was performed using an IPA tool (Qiagen). A heat map was clustered with top differentially expressed genes by hierarchical clustering using R. For scRNA-seq (Hosein et al, 2019), normal mouse pancreas, 40-day-old KIC (early KIC), and 60-day-old KIC pancreases (late KIC) were freshly isolated and enzymatically digested. A library was generated with the single-cell suspension using the 10× Chromium system (10× Genomics, Inc.).…”