Thrombin stimulates integrin β1-dependent adhesion of human pancreatic cancer cells to vitronectin through protease-activated receptor (PAR)-1.

Background/aims: The aim of this study was to investigate the effect of thrombin and the thrombin receptor protease-activated receptor (PAR)-1 on adhesion of human pancreatic cancer cell lines to extracellular matrices (ECMs) and to identify related integrins with these effects.
Methodology: Human pancreatic cancer cell lines SUIT-2 and its four sublines, and Panc- 1, AsPC-1 and MiaPaCa-2 were treated with thrombin, PAR-1 agonist TRAP-6, PAR-1 antagonist SCH79797, or anti-integrin ±vβ3, ±vβ5 and β1 monoclonal antibodies. Cells were incubated for 45 minutes on micro titer plates that were pre-coated with ECMs (fibronectin, laminin, vitronectin, type IV collagen). The number of adherent cells was measured by the MTT method.
Results: Eight human pancreatic cancer cell lines expressed PAR-1. Thrombin significantly enhanced adhesion of SUIT-2 and its sublines and MiaPaCa-2 to vitronectin, especially in the SUIT-2 subline S2-007. We obtained similar results on S2-007 cells through treatment with TRAP-6. However, SCH79797 inhibited the effect of thrombin. Furthermore, anti-integrin β1 antibody conspicuously inhibited 1U/mL thrombin-induced enhancement of adhesion to vitronectin.
Conclusions: Thrombin significantly enhanced adhesion of pancreatic cancer cells to vitronectin through PAR- 1 depending on the presence of integrin β1. Suppression of thrombin action by anti-integrin β1 antibody will become a useful therapy against pancreatic cancer.