Carcinogenesis Advance Access published online on June 22, 2009
Carcinogenesis, doi:10.1093/carcin/bgp153
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Met receptor tyrosine kinase transactivation is involved in proteinase-activated receptor 2-mediated hepatocellular carcinoma cell invasion
1 Department of General, Visceral and Vascular Surgery
2 Institute of Anatomy II
3 Institute of Pathology
5 Electron Microscopy Center
6 Institute of Molecular Cell Biology, Medical Faculty, Friedrich Schiller University Jena, Jena, Germany
4 Institute of Biochemistry, Charité, Humboldt University of Berlin, Berlin, Germany
7 Canadian Institutes of Health Research Proteinases and Inflammation Network, Inflammation Research Network, Department of Pharmacology and Therapeutics, University of Calgary, Calgary, Canada T2N 4N1
* Correspondence: Roland Kaufmann, Research Lab., Department of General, Visceral and Vascular Surgery, Research Center Lobeda, Medical Faculty at the Friedrich Schiller University Jena, Erlanger Allee 101, D-07747 Jena, Germany, Phone: +49-9325870, Fax: +49-9325872, e-mail: roland.kaufmann{at}med.uni-jena.de
The expression of proteinase-activated receptor-2 (PAR2) in human hepatocellular carcinoma (HCC) was established by reverse-transcriptase-PCR, confocal immunofluorescence and electron microscopy in permanent cell lines, primary HCC cell cultures, and HCC tumour tissue. Stimulation of HCC cells with trypsin and the PAR2-selective activating peptide, 2-furoyl-LIGRLO-NH2, increased cell invasion across Matrigel. Both effects were blocked by a PAR2-selective pepducin antagonist peptide (pal-PAR2) and by PAR2 silencing with specific siRNA. PAR2-initiated HCC cell invasion was also blocked by inhibiting the hepatocyte growth factor receptor (Met receptor tyrosine kinase) with the receptor-targeted kinase inhibitors, SU 11274 and PHA 665752, or by down regulation of Met with specific siRNA. The involvement of Met in PAR2-mediated HCC invasive signaling was further supported by the finding that treatment of HCC cells with trypsin or the PAR2-selective agonist peptide, 2-furoyl-LIGRLO-NH2, stimulated Met activation-phosphorylation. In addition, Met-dependent stimulation of p42/p44 MAPKinases was found to be critical for the PAR2-Met receptor tyrosine kinase invasive signaling axis in HCC cells. Our study establishes an important link between the proteinase-activated receptor 2 and Met receptor tyrosine kinase signaling in promoting hepatocellular carcinoma cell invasion.
Key Words: proteinase-activated receptor 2 • PAR2 • hepatocellular carcinoma • cell invasion • Met receptor tyrosine kinase
Received January 20, 2009; revised May 21, 2009; accepted June 16, 2009.