title: Examination of the signal transduction pathways leading to activation of gelatinolytic activity by interleukin-1alpha and Porphyromonas gingivalis in human osteosarcoma cells.
abstract: BACKGROUND
  Recently, evidence show that matrix metalloproteinases (MMP) play an important role in the pathogenesis of periodontal diseases. However, the mechanisms and signal transduction pathways involved in the production of MMPs in human osteosarcoma cells are not fully understood.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the gelatinolytic activity in human osteosarcoma cells stimulated with interleukin-1alpha (IL-1alpha) or Porphyromonas gingivalis in the absence or presence of SB203580 (p38 inhibitor), U0126 [mitogen-activated protein kinase kinase (MEK) inhibitor], and LY294002 [phosphatidylinositaol 3-kinase (PI3K) inhibitor].
  
  
  METHODS
  IL-1alpha and the supernatants of P. gingivalis were used to evaluate gelatinolytic activity in human osteosarcoma cells using gelatin zymography. Furthermore, to search possible signal transduction pathways, SB203580, U0126, and LY294002 were added to test how they modulated the gelatinolytic activity.
  
  
  RESULTS
  Gelatin zymography demonstrated that the latent proforms of gelatinases MMP-2 and MMP-9 were released by human osteosarcoma cells. Secretion of MMP-9 was time-dependent by stimulating with IL-1alpha or P. gingivalis. In addition, SB203580, U0126, and LY294002 significantly reduced the IL-1alpha or P. gingivalis-stimulated MMP-9 production, respectively (p < 0.05). However, none of the kinase inhibitors affected the MMP-2 level compared with the control during the 4-day culture period (p > 0.05).
  
  
  CONCLUSIONS
  Our findings demonstrated that IL-1alpha and P. gingivalis enhance MMP-9 production in human osteosarcoma cells, and the signal transduction pathways p38, MEK, and PI3K are involved in the inhibition of MMP-9. SB203580, U0126, and LY294002 suppress MMP-9 production and/or activity and may therefore be valuable therapeutics in MMP-mediated periodontal destruction, and might be proved clinically useful agents, in combination with standard treatment modalities, in the treatment of periodontitis.
authors.affiliation: Department of Periodontics, Institute of Stomatology, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Yu-Chao
authors.initials: YC
authors.lastname: Chang
authors.forename: Shu-Chen
authors.initials: SC
authors.lastname: Chu
authors.forename: Shun-Fa
authors.initials: SF
authors.lastname: Yang
authors.forename: Yih-Shou
authors.initials: YS
authors.lastname: Hsieh
authors.forename: Li-Chiu
authors.initials: LC
authors.lastname: Yang
authors.forename: Fu-Mei
authors.initials: FM
authors.lastname: Huang
mesh_terms: D017077:Culture Media, Conditioned / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D018093:Gelatinases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D006801:Humans; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010006:Osteoblasts / Q000201:enzymology; D012516:Osteosarcoma; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000378:metabolism; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D017077:Culture Media, Conditioned; D007375:Interleukin-1; D019869:Phosphatidylinositol 3-Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D018093:Gelatinases