title: S100A4 regulates membrane induced activation of matrix metalloproteinase-2 in osteosarcoma cells.
abstract: To study the role of the metastasis associated protein S100A4, an osteosarcoma cell line (OHS) with a high level of this protein was transfected with a vector containing a ribozyme that degrades S100A4 mRNA and, as controls, OHS cells were transfected with the vector alone. We have followed up our previous investigation (Bjørnland et al. 1999) by a detailed investigation of these cell lines' synthesis of MMP and TIMP proteins at different cell densities. It is shown that the cell lines with a low S100A4 level produced a reduced amount of immunoreactive MMP-2 at cellular subconfluence, while at confluence there was no difference compared to the control cells. The cell lines with a reduced S100A4 level produced less of the activated form of MMP-2 (62-kDa) and less TIMP-1 than the corresponding control cells, independent of cell density. Isolated cell membranes from cell lines with a reduced S100A4 level contained less MT1-MMP, MMP-2 and TIMP-2 compared to the control cells. Activation of exogenously added proMMP-2 was less effective with the former membrane preparations. It appeared that the mechanism behind the S100A4 dependent activation of proMMP-2 varied with cell density, as SN50, a peptide inhibitor of NF-kappaB nuclear translocation reduced the activation of MMP-2 at low cell density, but had no effect at high cell density. Thus, one of the mechanisms by which S100A4 may exert its effect on metastasis of some tumors is by regulating the MMP-2 activity.
authors.affiliation: Department of Biochemistry, Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
authors.forename: Berit
authors.initials: B
authors.lastname: Mathisen
authors.forename: Rune I
authors.initials: RI
authors.lastname: Lindstad
authors.forename: Janne
authors.initials: J
authors.lastname: Hansen
authors.forename: Sara Ann
authors.initials: SA
authors.lastname: El-Gewely
authors.forename: Gunhild M
authors.initials: GM
authors.lastname: Maelandsmo
authors.forename: Eivind
authors.initials: E
authors.lastname: Hovig
authors.forename: Oystein
authors.initials: O
authors.lastname: Fodstad
authors.forename: Thrina
authors.initials: T
authors.lastname: Loennechen
authors.forename: Jan-Olof
authors.initials: JO
authors.lastname: Winberg
mesh_terms: D001859:Bone Neoplasms / Q000201:enzymology*; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D017077:Culture Media, Conditioned; D004789:Enzyme Activation; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D012516:Osteosarcoma / Q000201:enzymology*; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000494:pharmacology*; D019714:Tissue Inhibitor of Metalloproteinases / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D002135:Calcium-Binding Proteins; D017077:Culture Media, Conditioned; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; D019714:Tissue Inhibitor of Metalloproteinases; C077591:S100A4 protein, human; D020778:Matrix Metalloproteinase 2