Thrombin‐mediated hepatocellular carcinoma cell migration: Cooperative action via proteinase‐activated receptors 1 and 4

Abstract

Proteinase-activated receptor-1 (PAR(1)), a thrombin receptor and the prototype of a newly discovered G-protein-coupled receptor subfamily, plays an important role in tumor development and progression. In this study, we documented the expression of the thrombin receptors PAR(1), PAR(3), and PAR(4) in permanent hepatocellular carcinoma (HCC) cell lines and primary HCC cell cultures. Stimulation of HCC cells with thrombin and the PAR(1)-selective activating peptide, TFLLRN-NH(2), increased transmembrane migration across a collagen barrier. This effect was blocked by the PAR(1) antagonist SCH 79797, confirming that the PAR(1) thrombin receptor subtype is involved in regulating hepatoma cell migration. In addition, the PAR(4)-selective agonist, AYPGKF-NH(2), also stimulated HCC cell migration whilst the PAR(4) antagonist, trans-cinnamoyl-YPGKF-NH(2), attenuated the effect of thrombin on HCC cell migration. PAR(1)- and PAR(4)-triggered HCC cell migration was blocked by inhibiting a number of key mediators of signal transduction, including G proteins of the G(i)/G(o) family, matrix metalloproteinases, ERK/MAPKinase, cyclic AMP-dependent protein kinase, Src tyrosine kinase, and the EGF receptor kinase. Our data point to a cooperative PAR(1)/PAR(4) signaling network that contributes to thrombin-mediated tumor cell migration. We suggest that a combined inhibition of coagulation cascade serine proteinases, the two PARs and their complex signaling pathways may provide a new strategy for treating hepatocellular carcinoma.

Down-regulation of Protease-activated Receptor 4 in Lung Adenocarcinoma is Associated with a More Aggressive Phenotype

“…Positive expression of PAR4 in some tumors have been found in previous studies and is thought to be involved in hepatocellular carcinoma cell migration and colon cancer progression (Kaufmann et al, 2007;Gratio et al, 2009). It was also reported that PAR4 activation contributed to the hematogenous metastasis of melanoma using the knockout mice (Camerer et al, 2004).…”

“…For instance, Primary hepatic cell cancer (HCC) was reported to be negative in one study (Rullier et al, 2006). While another reported a 100% positivity on 2 primary HCC cells and two cancer cell lines (Kaufmann et al, 2007). RT-PCR revealed no PAR4 mRNA in the LnCaP prostate cell line and MDA-MB-231 breast cell line while by FACS analysis they were shown to be positive (Elste et al, 2010).…”

“…The physiological and potential pathological functions of PAR4 in lung epithelial cells have yet to been defined, and studies investigating the role of PAR4 in cancer have had conflicting results (Rullier et al, 2006;Kaufmann et al, 2007;Elste et al, 2010). Our research was aimed at resolving these issues, by investigating PAR4 expression in primary lung adenocarcinomas as well as cell culture models.…”

Proteomic Effects of the Coagulation Proteinase Thrombin on LX-2 Hepatic Stellate Cells

“…PLA2 is known to be involved in hepatic stellate cell activation (19) and is critically implicated in thrombininduced signalling in different cell types including platelets (20,21) and endothelial cells (22)(23)(24). In addition, from recently published data, a role for thrombin in liver fibrosis and hepatocellular carcinoma progression has been suggested (25,26).…”

Green tea polyphenol epigallocatechin-3-gallate inhibits thrombin-induced hepatocellular carcinoma cell invasion and p42/p44-MAPKinase activation

“…Therefore, a role for the thrombin-PAR 1/4 -triggered signaling in HCC progression has been suggested (28). In this context, it is important to note that hepatocellular carcinoma (HCC) belongs to the 'coagulation type' tumors, in which there is an important role for thrombin formation within the tumor microenvironment (29,30).…”