Loss of hepatocyte growth factor activator inhibitor type 1 participates in metastatic spreading of human pancreatic cancer cells in a mouse orthotopic transplantation model.
Bottom Line: Matriptase is involved in pericellular processing of biologically active molecules, including protease-activated receptor-2 (PAR-2).Previously we reported that S2-CP8 cells, a metastatic variant of the SUIT-2 human pancreatic adenocarcinoma cell line, showed markedly decreased HAI-1 expression.Matriptase activity was suppressed by the expression of HAI-1.
Affiliation: Section of Oncopathology and Regenerative Biology, Department of Pathology, University of Miyazaki, Miyazaki, Japan; Clinical Research Center, The 2nd Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China.Show MeSH
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Mentions: Previously we reported that S2-CP8 cells, a highly metastatic subline from lungs and selected from SUIT-2, showed markedly decreased HAI-1 expression compared to the parent line. To determine whether the loss of HAI-1 is directly involved in S2-CP8 cell invasion and metastasis or is simply an epiphenomenon that occurred after the selection of the metastatic variant, we generated S2-CP8 cells that expressed HAI-1 under the control of a Tet-inducible promoter using the pLenti6.3 expression vector system (S2-CP8_HAI-1tet). Two sublines (S2-CP8_HAI-1tet#1 and #2) were isolated in which significant HAI-1 protein expression was induced by Tet treatment (Fig.1a). In accordance with the previous report, HAI-1 expression was barely detectable in parent S2-CP8 cells (not shown) and mock-transfected S2-CP8 cells (S2-CP8_mock) (Fig.1a). It should be noted that even in the absence of Tet, very low HAI-1 levels were detectable in S2-CP8_HAI-1tet cells by immunoblotting and RT-PCR (Fig.1a,b). The parent S2-CP8 cells expressed membrane-anchored serine proteases that can be regulated by HAI-1, such as matriptase, TMPRSS13, TMPRSS4 and prostasin. The mRNA levels of these proteases were not altered by the forced overexpression of HAI-1 (Fig.1b). Among presumed matriptase substrates, PAR-2 and uPA were also expressed by S2-CP8 cells. Although HGF, another important matriptase substrate, was not expressed by these cells, its receptor c-MET was expressed (Fig.1b). The Tet-induced overexpression of HAI-1 modestly enhanced the growth rate of S2-CP8 cells (Fig.1c) and resulted in a more epithelial morphology in vitro (Fig.1d).
Affiliation: Section of Oncopathology and Regenerative Biology, Department of Pathology, University of Miyazaki, Miyazaki, Japan; Clinical Research Center, The 2nd Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China.