title: Effects of alendronate on human osteoblast-like MG63 cells and matrix metalloproteinases.
abstract: OBJECTIVE
  The objective of this study was to examine the effects of alendronate on the expression and activity of matrix metalloproteinases (MMPs) and the expression of the tissue inhibitors of MMPs (TIMPs) from human osteoblast-like MG63 cells.
  
  
  METHODS
  MG63 cells were exposed to various concentrations of alendronate. Cell proliferation and cytotoxicity were evaluated by water-soluble tetrazolium-1 and lactate dehydrogenase, respectively. MG63-mediated collagen degradation was assessed utilising Type I collagen assays. Conditioned media and membrane extracts were collected for Western blot analyses of select MMPs and TIMPs. Gelatin zymography gels were incubated with alendronate to assess its effects on MMP-2 activity.
  
  
  RESULTS
  Alendronate affected MG63 proliferation and cytotoxicity at concentrations equal to/or greater than 10(-5) M (all p < 0.05). There were no significant differences in the collagen degrading ability of treated cells at non-toxic levels vs. untreated cells. Alendronate had no effects on the expression of MMP-2 or MT1-MMP (membrane type-1 MMP) in the conditioned media or membrane extracts, and of MMP-1 or TIMP-2 in the conditioned media. TIMP-2 in the membrane extracts was not detectable. MMP-2 activity in the zymograms was inhibited by 10(-3) and 10(-2) M alendronate.
  
  
  CONCLUSIONS
  Alendronate at 10(-5) M or higher was toxic to the cells. Alendronate at 10(-8) to 10(-6) M did not alter the expression of MMP-1, MMP-2, MT1-MMP or TIMP-2, as well as did not alter collagen degradation. Alendronate inhibited MMP-2 activity at 10(-3) and 10(-2) M in the zymograms. In conclusion, non-toxic levels of alendronate (10(-8) to 10(-6) M) did not alter MMP expression in MG63 cells or inhibit MMP-2 activity.
authors.affiliation: Department of Oral Biology, Indiana University School of Dentistry, Indianapolis, IN 46202, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.forename: Fengyu
authors.initials: F
authors.lastname: Song
authors.forename: Weiping
authors.initials: W
authors.lastname: Zhang
authors.forename: Brent E
authors.initials: BE
authors.lastname: Sexton
authors.forename: L Jack
authors.initials: LJ
authors.lastname: Windsor
mesh_terms: D019386:Alendronate / Q000494:pharmacology*; D000704:Analysis of Variance; D015153:Blotting, Western; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation; D003094:Collagen / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects* / Q000378:metabolism*; D010006:Osteoblasts / Q000187:drug effects*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism
chemical_list: D050071:Bone Density Conservation Agents; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D003094:Collagen; D007770:L-Lactate Dehydrogenase; D020778:Matrix Metalloproteinase 2; D019386:Alendronate