Proteomic analyses of ECM during pancreatic ductal adenocarcinoma progression reveal different contributions by tumor and stromal cells

Abstract

Pancreatic ductal adenocarcinoma (PDAC) has prominent extracellular matrix (ECM) that compromises treatments yet cannot be nonselectively disrupted without adverse consequences. ECM of PDAC, despite the recognition of its importance, has not been comprehensively studied in patients. In this study, we used quantitative mass spectrometry (MS)-based proteomics to characterize ECM proteins in normal pancreas and pancreatic intraepithelial neoplasia (PanIN)- and PDAC-bearing pancreas from both human patients and mouse genetic models, as well as chronic pancreatitis patient samples. We describe detailed changes in both abundance and complexity of matrisome proteins in the course of PDAC progression. We reveal an early up-regulated group of matrisome proteins in PanIN, which are further up-regulated in PDAC, and we uncover notable similarities in matrix changes between pancreatitis and PDAC. We further assigned cellular origins to matrisome proteins by performing MS on multiple lines of human-to-mouse xenograft tumors. We found that, although stromal cells produce over 90% of the ECM mass, elevated levels of ECM proteins derived from the tumor cells, but not those produced exclusively by stromal cells, tend to correlate with poor patient survival. Furthermore, distinct pathways were implicated in regulating expression of matrisome proteins in cancer cells and stromal cells. We suggest that, rather than global suppression of ECM production, more precise ECM manipulations, such as targeting tumor-promoting ECM proteins and their regulators in cancer cells, could be more effective therapeutically.

Beyond just a tight fortress: contribution of stroma to epithelial-mesenchymal transition in pancreatic cancer

“… 26 – 30 CAFs are the major producers of ECM proteins, which consist predominantly of collagens, fibronectin, and laminin, 31 although recent evidence suggests PDAC cells can also contribute to deposition of the ECM. 32 Chronic, high-ordered structuring of these ECM proteins results in a stiff, three-dimensional mesh which, in combination with high molecular weight glycosaminoglycans such as hyaluronan, form a milieu with high interstitial pressure that collapses blood vessels and limits delivery of oxygen and nutrients. 33 , 34 In addition to these biophysical properties, ECM molecules have signaling function by triggering membrane receptors on PDAC cells and engaging pathways that contribute to EMT.…”

PYCR1-dependent proline synthesis in cancer-associated fibroblasts is required for the deposition of pro-tumorigenic extracellular matrix

“…The extracellular matrix (ECM) actively regulates tumour initiation, growth, metastasis and response to therapy [1][2][3][4] . Cancer-associated fibroblasts (CAFs) are mesenchymal cells abundant in the stroma of solid tumours and are the major producers of ECM 5 . CAFs can originate from normal resident fibroblasts (NFs) that have undergone activation and the production of vast amounts of ECM is a hallmark event of their activation [6][7][8] .…”

Establishment and Characterization of Paired Primary Cultures of Human Pancreatic Cancer Cells and Stellate Cells Derived from the Same Tumor

“…Several recent reports have studied the complex interactions between PSCs and cancer cells based on analysis of their secretomes [42,60,61]. This prompted us to investigate the composition of the secretome from the paired primary PCCs and PSCs by proteomics-based analysis.…”