title: Urokinase receptor expression is upregulated by cell culture sparsity in breast cancer cell line BT-20.
abstract: BACKGROUND
  The processes of tumour cell migration and invasion are enhanced by urokinase activity mediated by the urokinase receptor on the cell surface. Various factors affect the expression of the urokinase receptor, and amongst them we have found evidence that cell culture dispersity strongly upregulates it in breast cancer cell line BT 20.
  
  
  METHODS
  Flow cytometry was used to quantify urokinase enzyme and urokinase receptors on the surfaces of cells cultured at different levels of dispersity.
  
  
  RESULTS
  Increasing the cell culture sparsity caused more than a doubling in the level of expression of the cell surface urokinase receptor in this cell line. A marked increase in the level of cell surface receptor-bound urokinase corresponding to the increase in the receptor itself also occurred in sparse cell cultures.
  
  
  CONCLUSIONS
  The marked effect of culture sparsity on the urokinase pathway may have important implications for the behaviour of tumour cells during the process of metastasis formation.
authors.affiliation: Department of Surgery, North Queensland Clinical School, University of Queensland, Townsville, Australia.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: N
authors.initials: N
authors.lastname: Wood
authors.forename: D
authors.initials: D
authors.lastname: Yellowlees
authors.forename: P K
authors.initials: PK
authors.lastname: Donnelly
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D002452:Cell Count; D018929:Cell Culture Techniques; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D055293:Receptors, Urokinase Plasminogen Activator; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator