title: Focal adhesion kinase regulates syndecan-2-mediated tumorigenic activity of HT1080 fibrosarcoma cells.
abstract: Expression of syndecan-2, a transmembrane heparan sulfate proteoglycan, is crucial for the tumorigenic activity in colon carcinoma cells. However, despite the high-level expression of syndecan-2 in mesenchymal cells, few studies have addressed the function of syndecan-2 in sarcoma cells. In HT1080 fibrosarcoma cells, we found that syndecan-2 regulated migration, invasion into Matrigel, and anchorage-independent growth but not cell-extracellular matrix adhesion or proliferation, suggesting that syndecan-2 plays different functional roles in fibrosarcoma and colon carcinoma cells. Consistent with the increased cell migration/invasion of syndecan-2-overexpressing HT1080 cells, syndecan-2 overexpression increased phosphorylation and interaction of focal adhesion kinase (FAK) and phosphatidylinositol 3-kinase (PI3K), membrane localization of T-lymphoma invasion and metastasis gene-1 (Tiam-1), and activation of Rac. Syndecan-2-mediated cell migration/invasion of HT1080 cells was diminished when (a) cells were cotransfected with nonphosphorylatable mutant FAK Y397F or with other FAK mutants lacking PI3K interactions, (b) cells were treated with a specific PI3K inhibitor, or (c) levels of Tiam-1 were knocked down with small interfering RNAs. Furthermore, expression of several FAK mutants inhibited syndecan-2-mediated enhancement of anchorage-independent growth in HT1080 cells. Taken together, these data suggest that syndecan-2 regulates the tumorigenic activities of HT1080 fibrosarcoma cells and that FAK is a key regulator of syndecan-2-mediated tumorigenic activities.
authors.affiliation: Department of Life Science, Division of Molecular Life Sciences and Center for Cell Signaling Research, Ewha Womans University, Seoul, Korea.
authors.forename: Haein
authors.initials: H
authors.lastname: Park
authors.forename: Innoc
authors.initials: I
authors.lastname: Han
authors.forename: Ho Jeong
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Eok-Soo
authors.initials: ES
authors.lastname: Oh
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D005354:Fibrosarcoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism*; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D053669:Syndecan-2; D014162:Transfection
chemical_list: D008562:Membrane Glycoproteins; D011509:Proteoglycans; C508245:SDC2 protein, human; D053669:Syndecan-2; D019869:Phosphatidylinositol 3-Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt