title: [Controlled expression of matrix metalloproteinase 9 promotes expression of invasive phenotype of human melanoma cells].
abstract: OBJECTIVE
  To investigate the correlation between matrix metalloproteinase 9 (MMP-9) expression and tumor metastasis, and explore the potential application of controlled expression of target gene in tumor gene therapy.
  
  
  METHODS
  One self-contained tetracycline-regulated retroviral vector containing sense cDNA of MMP-9 was constructed and transfected into an early-stage human melanoma cell line WM35, which did not express MMP-9. In vitro tests such as growth rate, MTT method, 3H-thymidine incorporation, colony forming ability in soft agar, in vitro invasion assay in Boyden chambers, as well as zymography and Western Blot experiment were used to analyze expression of MMPs and in vitro behavior of tumor cells before and after gene transfection.
  
  
  RESULTS
  In the presence of exogenous tetracycline, the expression of the transfected MMP-9 were under detectable level and no significant changes in cell behaviors were found when compared with vector-transfected control cells. But when the tetracycline was withdrew from the medium, the expression and activity of MMP-9 were significantly increased. The capacity of in vitro growth, colony forming ability in soft agar, invasion through Matrigel were enhanced remarkably.
  
  
  CONCLUSIONS
  Transfection of sense MMP-9 can enhance growth and invasion of melanoma cells, further confirming its important role in tumor invasion and metastasis.
authors.affiliation: Department of Pathology, Peking University School of Basic Medical Sciences, Beijing 100083, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Kong
authors.forename: Weigang
authors.initials: W
authors.lastname: Fang
authors.forename: Haohao
authors.initials: H
authors.lastname: Zhong
authors.forename: Wanjie
authors.initials: W
authors.lastname: Heng
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Bingquan
authors.initials: B
authors.lastname: Wu
mesh_terms: D002455:Cell Division; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000502:physiology*; D008545:Melanoma / Q000201:enzymology / Q000473:pathology*; D009361:Neoplasm Invasiveness; D013752:Tetracycline / Q000494:pharmacology; D014162:Transfection
chemical_list: D020780:Matrix Metalloproteinase 9; D013752:Tetracycline