Interaction between Cancer Cells and Stromal Fibroblasts Is Required for Activation of the uPAR-uPA-MMP-2 Cascade in Pancreatic Cancer Metastasis

Abstract

Purpose: Interaction between tumor cells and surrounding stromal fibroblast (SF) plays a critical role in tumor growth and invasion. The aim of the study is to determine the role of SF in regulating the invasive behaviors of pancreatic cancer by evaluating the mode of SF activating the urokinase plasminogen activator (uPA)-plasmin-matrix metalloproteinase (MMP)-2 cascade. Experimental Design: The expression patterns of uPA, MMP-2, and uPA receptor (uPAR) in human metastatic pancreatic cancer were analyzed by immunohistochemistry and the roles of SF in activation of the uPA-plasmin-MMP-2 cascade were evaluated by coculturing pancreatic cancer cell lines with SF. Results: uPA expression and fibroblastic uPAR expression were correlated with liver metastasis of human pancreatic cancer. MMP-2 rather than MMP-9 was activated in the metastatic pancreatic cancer. In the in vitro culture system, the coculture of peritumor fibroblasts with metastatic pancreatic cancer BxPc3 cells resulted in activation of MMP-2 and up-regulation of uPAR expression. In this coculture system, the uPA-plasminogen cascade was involved in MMP-2 activation. This activation required a direct interaction between SF and cancer cells. In the coculture system, intergrin a 6 h 1 expression was increased in BxPc3 cells, and blocking the function of integrin a 6 h 1 decreased the activation of uPA and MMP-2. This suggests that interaction between integrins of cancer cells and the uPARs of the SF might be involved in the activation of the uPAR-uPA-MMP-2 cascade. Conclusion: Our results suggest that SF plays a role in promoting pancreatic cancer metastasis via activation of the uPA-plasminogen-MMP-2 cascade.

SERPINB3 modulates TGF-β expression in chronic liver disease

“…33,34 Proteolytic mechanisms are indeed additional players involved in matrix remodeling and crucial roles of cysteine and serine proteases and their inhibitors have been recognized not only for tissue remodeling, but also for angiogenesis, stromal invasion, and formation of metastases by malignant cancer cells. 35,36 In this study, we have confirmed that TGF-b1 is expressed in chronically damaged hepatocytes, and we have shown for (a) TGF-b1 mRNA induction in HepG2, Huh7 cells, and primary human hepatocytes. TGF-b1 transcripts were assessed in each sample of transiently transfected cells at 48 h from the transfection with SERPINB3 (gray bars) or with the empty vector (white bars) by real-time PCR using primers specific for the human TGF-b1 gene.…”

Antagonistic Anti-urokinase Plasminogen Activator Receptor (uPAR) Antibodies Significantly Inhibit uPAR-mediated Cellular Signaling and Migration

“…Therefore, we were inclined to accept that the uPAR interaction with uPA and ␤1 integrins ultimately lead to the activation of matrix-degrading MMPs. Additionally, the uPAR/uPA interaction has been suggested to be involved in the activation of ECM-degrading MMP2 (32). To resolve whether uPAR contributed to invasion beyond that of MMPs, MT1-MMP in particular, we conducted another invasion assay where we co-treated H1299 cells with either 2G10 or 3C6 and the broad-spectrum MMP inhibitor GM6001 or an antibody against the catalytic domain of MT1-MMP.…”

Heme oxygenase-1 inhibits breast cancer invasion via suppressing the expression of matrix metalloproteinase-9

“…Proteolytic degradation of the extracellular matrix by tumor cell-secreted proteases, including plasminogen activators, serine proteinases, and matrix metalloproteinases (MMP), is important for tumor angiogenesis, invasion, and metastasis (1,2). Increased expressions of MMPs, particularly MMP-2 (gelatinase A; 72-kDa type IV collagenase) and MMP-9 (gelatinase B; 92-kDa type IV collagenase), have been intensely correlated with the malignancy of tumors and poor survival in patients, especially with breast cancer (3,4).…”