title: Transforming growth factor-β signalling controls human breast cancer metastasis in a zebrafish xenograft model.
abstract: BACKGROUND
  The transforming growth factor beta (TGF-β) signalling pathway is known to control human breast cancer invasion and metastasis. We demonstrate that the zebrafish xenograft assay is a robust and dependable animal model for examining the role of pharmacological modulators and genetic perturbation of TGF-β signalling in human breast tumour cells.
  
  
  METHODS
  We injected cancer cells into the embryonic circulation (duct of cuvier) and examined their invasion and metastasis into the avascular collagenous tail. Various aspects of the TGF-β signalling pathway were blocked by chemical inhibition, small interfering RNA (siRNA), or small hairpin RNA (shRNA). Analysis was conducted using fluorescent microscopy.
  
  
  RESULTS
  Breast cancer cells with different levels of malignancy, according to in vitro and in vivo mouse studies, demonstrated invasive and metastatic properties within the embryonic zebrafish model that nicely correlated with their differential tumourigenicity in mouse models. Interestingly, MCF10A M2 and M4 cells invaded into the caudal hematopoietic tissue and were visible as a cluster of cells, whereas MDA MB 231 cells invaded into the tail fin and were visible as individual cells. Pharmacological inhibition with TGF-β receptor kinase inhibitors or tumour specific Smad4 knockdown disturbed invasion and metastasis in the zebrafish xenograft model and closely mimicked the results we obtained with these cells in a mouse metastasis model. Inhibition of matrix metallo proteinases, which are induced by TGF-β in breast cancer cells, blocked invasion and metastasis of breast cancer cells.
  
  
  CONCLUSIONS
  The zebrafish-embryonic breast cancer xenograft model is applicable for the mechanistic understanding, screening and development of anti-TGF-β drugs for the treatment of metastatic breast cancer in a timely and cost-effective manner.
authors.forename: Yvette
authors.initials: Y
authors.lastname: Drabsch
authors.forename: Shuning
authors.initials: S
authors.lastname: He
authors.forename: Long
authors.initials: L
authors.lastname: Zhang
authors.forename: B Ewa
authors.initials: BE
authors.lastname: Snaar-Jagalska
authors.forename: Peter
authors.initials: P
authors.lastname: ten Dijke
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D002867:Chromones / Q000494:pharmacology; D004149:Dioxoles / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D004195:Disease Models, Animal; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D004625:Embryo, Nonmammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D034741:RNA, Small Interfering / Q000494:pharmacology; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects; D051899:Smad2 Protein / Q000378:metabolism; D051901:Smad4 Protein / Q000235:genetics / Q000378:metabolism; D054852:Small Molecule Libraries / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays; D015027:Zebrafish / Q000196:embryology / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D002867:Chromones; D004149:Dioxoles; D004151:Dipeptides; D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D009025:Morpholines; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D034741:RNA, Small Interfering; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; D051901:Smad4 Protein; D054852:Small Molecule Libraries; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins; C497786:smad2 protein, zebrafish; C490809:smad4a protein, zebrafish; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I