Proteinase-activated receptor 2 (PAR2) in cholangiocarcinoma (CCA) cells: effects on signaling and cellular level

In this study, we demonstrate functional expression of the proteinase-activated receptor 2 (PAR2), a member of a G-protein receptor subfamily in primary cholangiocarcinoma (PCCA) cell cultures. Treatment of PCCA cells with the serine proteinase trypsin and the PAR2-selective activating peptide, furoyl-LIGRLO-NH2, increased migration across a collagen membrane barrier. This effect was inhibited by a PAR2-selective pepducin antagonist peptide (P2pal-18S) and it was also blocked with the Met receptor tyrosine kinase (Met) inhibitors SU 11274 and PHA 665752, the MAPKinase inhibitors PD 98059 and SL 327, and the Stat3 inhibitor Stattic. The involvement of Met, p42/p44 MAPKinases and Stat3 in PAR2-mediated PCCA cell signaling was further supported by the findings that trypsin and the PAR2-selective agonist peptide, 2-furoyl-LIGRLO-NH2, stimulated activating phosphorylation of these signaling molecules in cholangiocarcinoma cells. With our results, we provide a novel signal transduction module in cholangiocarcinoma cell migration involving PAR2-driven activation of Met, p42/p44 MAPKinases and Stat3.