title: Functional role of matrix metalloproteinases in ovarian tumor cell plasticity.
abstract: OBJECTIVE
  We previously demonstrated that aggressive ovarian cancer cells are able to display in vitro vasculogenic mimicry, which is reflected by their ability to form vasculogenic-like networks in 3-dimensional cultures and to express vascular cell-associated markers. The goal of this study was to examine the functional role of specific matrix metalloproteinases in the formation of vasculogenic-like networks and extracellular matrix remodeling in vitro. We also investigated the clinical relevance of matrix metalloproteinase-2 and -9 and membrane type 1-matrix metalloproteinase in human ovarian cancers with evidence of tumor cell-lined vasculature.
  
  
  METHODS
  Ovarian cancer cells (A2780-PAR, SKOV3, and EG) were seeded onto separate 3-dimensional cultures that contained either Matrigel or type I collagen, in the absence of endothelial cells or fibroblasts. These cultures were treated with either chemically modified tetracycline-3 (general matrix metalloproteinase inhibitor), recombinant tissue inhibitor of metalloproteinase-1 or -2, or function-blocking antibodies to matrix metalloproteinase-2 or -9 or membrane type 1-matrix metalloproteinase. In addition, 78 invasive epithelial ovarian cancers were evaluated for expression of matrix metalloproteinase-2 and -9 and membrane type 1-matrix metalloproteinase and correlated with various clinical parameters.
  
  
  RESULTS
  The aggressive ovarian cancer cells (SKOV3 and EG) were able to form in vitro vasculogenic-like networks and contract 3-dimensional collagen I gels, whereas the poorly aggressive A2780-PAR cell line did not. Chemically modified tetracycline-3 completely blocked the network formation. Blocking antibodies to matrix metalloproteinase-2 and membrane type 1-matrix metalloproteinase inhibited the formation of the vasculogenic-like networks and collagen gel contraction, but the antibody to matrix metalloproteinase-9 had no effect on network formation and minimal effect on gel contraction. Treatment of 3-dimensional cultures with tissue inhibitor of metalloproteinase-2 retarded the network formation and only small, partially developed structures were noted that did not form network connections. Tissue inhibitor of metalloproteinase-1 had no appreciable effect on the extent or efficiency of network formation. Human invasive ovarian cancers with evidence of tumor cell-lined vasculature were significantly more likely to have strong epithelial and stromal matrix metalloproteinase-2 and -9 and membrane type 1-matrix metalloproteinase expression (all probability values were <.05).
  
  
  CONCLUSIONS
  Matrix metalloproteinase-2 and membrane type 1-matrix metalloproteinase appear to play a key role in the development of vasculogenic-like networks and matrix remodeling by aggressive ovarian cancer cells. Human ovarian cancers with matrix metalloproteinase overexpression are more likely to have tumor cell-lined vasculature. These results may offer new insights for consideration in ovarian cancer treatment strategies.
authors.affiliation: Department of Gynecologic Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA. asood@mdanderson.org
authors.forename: Anil K
authors.initials: AK
authors.lastname: Sood
authors.forename: Mavis S
authors.initials: MS
authors.lastname: Fletcher
authors.forename: Jeremy E
authors.initials: JE
authors.lastname: Coffin
authors.forename: Maria
authors.initials: M
authors.lastname: Yang
authors.forename: Elisabeth A
authors.initials: EA
authors.lastname: Seftor
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Gruman
authors.forename: David M
authors.initials: DM
authors.lastname: Gershenson
authors.forename: Mary J C
authors.initials: MJ
authors.lastname: Hendrix
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D045744:Cell Line, Tumor / Q000201:enzymology; D005260:Female; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000378:metabolism*; D008875:Middle Aged; D018716:Molecular Mimicry; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D009389:Neovascularization, Pathologic; D010051:Ovarian Neoplasms / Q000201:enzymology* / Q000473:pathology
chemical_list: D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2