Circulating Vascular Endothelial Growth Factor Correlates with Systemic Thrombin Generation in Patients with Pancreatic Carcinoma

Thrombin enhances adhesion in pancreatic cancer in vitro through the activation of the thrombin receptor PAR 1

BACKGROUND

Thrombin, the central enzyme of the coagulation cascade, induces proliferation in different solid tumours. The effect is mainly mediated through the functional thrombin receptor PAR 1, a member of the G-protein coupled receptor family. The aim of this study was to assess the role of thrombin on adhesion of pancreatic cancer to extracellular matrix proteins and endothelial cells in vitro.

MATERIALS AND METHODS

The human pancreatic adenocarcinoma cell line MIA PaCa-2 was treated with thrombin and the thrombin-receptor-activating peptide (TRAP), respectively. As a control the cells were pre-incubated with the thrombin-receptor-inhibiting peptide (T1). The cells were incubated on microtiter plates, which were pre-coated with extracellular matrix proteins (fibronectin, laminin, collagen IV) or human umbilical vein endothelial cells (HUVECs), for 30 and 60 min, respectively. The number of adherent cells were measured using the MTT method. ANOVA was used for statistical analysis.

RESULTS

Thrombin enhanced the adhesion of MIA PaCa-2 cells to extra-cellular matrix proteins and endothelial cells significantly (P< or =0.001). The effects of thrombin could be mimicked by TRAP. Pre-incubation with T1 inhibited the effect.

CONCLUSION

Thrombin enhances adhesion of pancreatic adenocarcinoma to extracellular matrix proteins and endothelial cells in vitro. The effect is mediated through the thrombin receptor PAR 1. The results emphasize the role of thrombin and PAR 1 in pancreatic tumour biology.

Growth factors, receptors, and molecular alterations in pancreatic cancer. Putting it all together

Because of the dismal prognosis of advanced ductal pancreatic adenocarcinoma, recent investigational strategies have focused on improved detection and therapeutic intervention in early-stage pancreatic cancer. The obvious cost constraints of screening populations at risk but with a low tumor yield will restrict screening protocols to only the highest risk groups (hereditary pancreatitis = age 50, certain hereditary pancreatic cancer kindreds). The vast majority of patients, either lacking or exhibiting an inherited predisposition to pancreatic cancer, will continue to present with disease not resectable for cure. The authors believe that the best hope for these patients lies in the further delineation of the integrative pathophysiology driving tumor growth; this would facilitate the future development of a computer program or other modality that would predict the dominant pathways driving the growth and spread of each tumor based on its "molecular profile." This article reviews the authors' current knowledge regarding the growth factors, receptors, and molecular alterations driving uncontrolled proliferation, local invasion, and metastatic spread of these tumors. The current and potential contributions of studies in cohorts with an inherited predisposition to pancreatic cancer to this pathophysiologic model are also discussed. The future strategy for incorporating this information into a working pathophysiologic road map with clinical relevance is subsequently outlined.