title: Fibroblasts promote breast cancer cell invasion by upregulating tumor matrix metalloproteinase-9 production.
abstract: BACKGROUND
  Thrombospondin-1 (TSP-1) promotes breast cancer cell invasion of collagen by upregulating matrix metalloproteinase-9 (MMP-9) production. Stromal TSP-1 may play a role in regulating tumor cell invasion. We hypothesize that fibroblasts promote breast cancer cell invasion by upregulating the production of MMP-9 through TSP-1.
  
  
  METHODS
  MDA-MB-231 human breast carcinoma cells were grown alone or in coculture with human fibroblasts. Gelatin zymography and Western immunoblot analysis for MMP-9 were performed on the coculture cell media and the single cell media. Inhibition of fibroblast-mediated breast tumor cell invasion by an anti-TSP-1 or an anti-MMP-9 antibody was evaluated using a modified Boyden chamber.
  
  
  RESULTS
  Coculture experiments showed an increased production of MMP-9 when compared with breast cancer single cell culture or fibroblast single cell culture experiments as demonstrated by zymography and Western immunoblot analysis. Fibroblast-stimulated MMP-9 production was comparable with TSP-1-stimulated MMP-9 production. Anti-TSP-1 antibody and anti-MMP-9 antibody inhibited fibroblast-stimulated tumor cell invasion to 30% and 26% of controls, respectively (P <.05).
  
  
  CONCLUSIONS
  Fibroblasts may regulate breast cancer cell invasion by promoting tumor MMP-9 production through TSP-1. Inhibition of stromal TSP-1 stimulation of MMP-9 synthesis may prevent matrix degradation necessary for tumor invasion and metastasis.
authors.affiliation: Department of Surgery, The Medical College of Georgia, Augusta 30912, USA.
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Wang
authors.forename: Daniel
authors.initials: D
authors.lastname: Albo
authors.forename: George P
authors.initials: GP
authors.lastname: Tuszynski
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D001943:Breast Neoplasms; D018920:Coculture Techniques; D003094:Collagen / Q000378:metabolism; D020405:Dermis / Q000166:cytology; D005260:Female; D005347:Fibroblasts / Q000201:enzymology* / Q000473:pathology*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism; D009361:Neoplasm Invasiveness; D019700:Thrombospondin 1 / Q000276:immunology / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000473:pathology; D015854:Up-Regulation
chemical_list: D000906:Antibodies; D019700:Thrombospondin 1; D003094:Collagen; D020780:Matrix Metalloproteinase 9