Up-regulation of N-cadherin by Collagen I-activated Discoidin Domain Receptor 1 in Pancreatic Cancer Requires the Adaptor Molecule Shc1

Abstract

Pancreatic ductal adenocarcinomas are highly malignant cancers characterized by extensive invasion into surrounding tissues, metastasis to distant organs, and a limited response to therapy. A main feature of pancreatic ductal adenocarcinomas is desmoplasia, which leads to extensive deposition of collagen I. We have demonstrated that collagen I can induce epithelialmesenchymal transition (EMT) in pancreatic cancer cells. A hallmark of EMT is an increase in the expression of the mesenchymal cadherin N-cadherin. Previously we showed up-regulation of N-cadherin promotes tumor cell invasion and that collagen I-induced EMT is mediated by two collagen receptors, ␣2␤1-integrin and discoidin domain receptor 1 (DDR1). DDR1 is a receptor-tyrosine kinase widely expressed during embryonic development and in many adult tissues and is also highly expressed in many different cancers. In the signaling pathway initiated by collagen, we have shown proline-rich tyrosine kinase 2 (Pyk2) is downstream of DDR1. In this study we found isoform b of DDR1 is responsible for collagen I-induced up-regulation of N-cadherin and tyrosine 513 of DDR1b is necessary. Knocking down Shc1, which binds to tyrosine 513 of DDR1b via its PTB (phosphotyrosine binding) domain, eliminates the upregulation of N-cadherin. The signaling does not require a functional SH2 domain or the tyrosine residues commonly phosphorylated in Shc1 but is mediated by the interaction between a short segment of the central domain of Shc1 and the proline-rich region of Pyk2. Taken together, these data illustrate DDR1b, but not DDR1a, mediates collagen I-induced N-cadherin up-regulation, and Shc1 is involved in this process by coupling to both DDR1 and Pyk2.Pancreatic cancer is currently the fourth leading cause of cancer-related mortality in the United States with a 5-year survival rate of ϳ6% (American Cancer Society, 2014). This unfortunate outcome is mainly due to the aggressive behavior of this cancer and the lack of symptoms early in the disease. One of the major features of pancreatic cancer is that during the early stages an extensive stromal reaction occurs called desmoplasia. A dense stroma forms, which consists of myofibroblasts (pancreatic stellate cells), abundant extracellular matrix, and different types of inflammatory cells including macrophages, mast cells, lymphocytes, and plasma cells (1, 2). The extracellular matrix components include collagens, fibronectin, hyaluronic acid, and proteoglycans, whereas the major part is type I collagen (3, 4).The atypical stroma plays many roles in pancreatic cancer. It changes the normal architecture of pancreatic tissue and induces an abnormal configuration of blood and lymphatic vessels resulting in a hypovascular and hypoxic microenvironment. It also presents a barrier to drug delivery and promotes tumor immunologic tolerance (2, 4). Previously, our laboratory showed that collagen I can induce epithelial-mesenchymal transition (EMT) 2 -like changes in pancreatic cancer mediated by two collagen receptors, ␣2␤1-integrin and ...

Inhibition of Discoidin Domain Receptor 1 Reduces Collagen-mediated Tumorigenicity in Pancreatic Ductal Adenocarcinoma

“…In PANC-1 cells, 7rh inhibited DDR1-mediated signaling induced by soluble collagen (50 µg/ml) in a concentration-dependent manner (Figure 3a). At pharmacologically-relevant concentrations, 7rh inhibited activation of PYK2 and PEAK1, signaling proteins downstream of DDR1 (40). However, 7rh did not affect the activation of focal adhesion kinase (FAK), an effector that has not been previously associated with DDR1-induced signaling (23).…”

“…In this study, 7rh-mediated inhibition of DDR1 in gastric cancer cells reduced tumorigenic characteristics in vitro and tumor growth in vivo . Finally, collagen signaling and DDR1 activity has been linked to epithelial plasticity (23,40). We found evidence that 7rh induced a more differentiated tumor cell phenotype, which is consistent with improved efficacy of standard chemotherapy.…”

Upregulated N‐cadherin expression is associated with poor prognosis in epithelial‐derived solid tumours: A meta‐analysis

“…Cadherins are a family of calcium‐dependent glycoproteins, which responsible for Ca 2+ ‐dependent cell‐cell adhesions. Of the members of this family, N‐cadherin (neuronal cadherin or cadherin‐2), a transmembrane glycoprotein, which is normally expressed in neuroectodermal and mesenchymal‐derived tissues, plays crucial role in lots of processes, such as cell‐cell adhesion, embryogenesis, gastrulation, neurulation, migration and invasion . Today, N‐cadherin is regarded as a vital marker of EMT .…”

“…Nevertheless, the prognostic role of N‐cadherin in tumours still remains controversially. Some studies suggested that expression of N‐cadherin was generally upregulated in prostate, breast cancer and urothelial tumours, and was associated with poorer clinical outcomes . In addition, the upregulation of N‐cadherin was significantly related with postoperative recurrence in hepatocellular carcinoma (HCC) patients .…”

“…Of the members of this family, N-cadherin (neuronal cadherin or cadherin-2), a transmembrane glycoprotein, which is normally expressed in neuroectodermal and mesenchymal-derived tissues, plays crucial role in lots of processes, such as cell-cell adhesion, embryogenesis, gastrulation, neurulation, migration and invasion. 4,[10][11][12][13] Today, N-cadherin is regarded as a vital marker of EMT. 14 Neoexpression or upregulated expression of N-cadherin has been reported to accelerate migration and invasion of cancer cells, which showed a contrary function to those of E-cadherin.…”