title: Differential roles of matrix metalloproteinase-9 and -2, depending on proliferation or differentiation of retinoblastoma cells.
abstract: OBJECTIVE
  To investigate the differential roles of matrix metalloproteinase (MMP)-9 and MMP-2 in the proliferation or differentiation of retinoblastoma cells.
  
  
  METHODS
  Cell proliferation assay with an MMP-9 inhibitor and cell viability assay with an MMP-2 inhibitor were performed in retinoblastoma cells with 5 ng/mL fibroblast growth factor 2 for proliferation, 0.1% bovine serum albumin for differentiation, or reverse transcriptase-polymerase chain reaction (RT-PCR) for MMP-9, MMP-2, and their tissue inhibitors TIMP-1 and TIMP-2. Immunohistochemistry for MMP-2 and nm23 was performed using an experimental model of retinoblastoma. With the use of an MMP-2 inhibitor, Western blot analysis was performed for neurofilament, extracellular signal-regulated kinases 1 and 2 (ERK 1/2), and phospho-ERK 1/2, and neurite length was measured in differentiated retinoblastoma cells.
  
  
  RESULTS
  With the proliferation of retinoblastoma cells, MMP-9 expression was upregulated without alteration of MMP-2, TIMP-1, or TIMP-2. However, proliferation was not affected by the inhibition of MMP-9 activity. Interestingly, only MMP-2 expression, colocalized with differentiated cells in retinoblastoma tissue, was significantly increased in the differentiation of retinoblastoma cells. Inhibition of MMP-2 activity did not affect cellular viability but attenuated neurite outgrowth and neurofilament expression of differentiated retinoblastoma cells, which was mediated through the suppression of ERK 1/2 activation.
  
  
  CONCLUSIONS
  The authors suggest that differential expression of MMP-9 and -2 could reflect biological features, such as proliferation and differentiation, of retinoblastoma cells. In particular, MMP-2 could be directly involved in the regulation of differentiation of retinoblastoma cells. Therefore, therapeutic targeting to MMP-2 may prove useful for reducing malignancy through the differentiation of retinoblastoma cells.
authors.affiliation: Fight Against Angiogenesis-Related Blindness Laboratory, Department of Ophthalmology, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Jeong Hun
authors.initials: JH
authors.lastname: Kim
authors.forename: Jin Hyoung
authors.initials: JH
authors.lastname: Kim
authors.forename: Chang Sik
authors.initials: CS
authors.lastname: Cho
authors.forename: Hyoung Oh
authors.initials: HO
authors.lastname: Jun
authors.forename: Dong Hun
authors.initials: DH
authors.lastname: Kim
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Yu
authors.forename: Kyu-Won
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation; D049109:Cell Proliferation; D002470:Cell Survival; D004195:Disease Models, Animal; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000502:physiology*; D020780:Matrix Metalloproteinase 9 / Q000502:physiology*; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D048053:Mitogen-Activated Protein Kinase 6 / Q000378:metabolism; D054778:NM23 Nucleoside Diphosphate Kinases / Q000378:metabolism; D016501:Neurites / Q000502:physiology; D019572:Retinal Neoplasms / Q000201:enzymology* / Q000473:pathology; D012175:Retinoblastoma / Q000201:enzymology* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D054778:NM23 Nucleoside Diphosphate Kinases; D019715:Tissue Inhibitor of Metalloproteinase-1; D016222:Fibroblast Growth Factor 2; D019716:Tissue Inhibitor of Metalloproteinase-2; D012710:Serum Albumin, Bovine; D048052:Mitogen-Activated Protein Kinase 3; D048053:Mitogen-Activated Protein Kinase 6; C517938:NME1 protein, human; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9