title: Loss of the endothelial glycocalyx is associated with increased E-selectin mediated adhesion of lung tumour cells to the brain microvascular endothelium.
abstract: BACKGROUND
  Arrest of metastasising lung cancer cells to the brain microvasculature maybe mediated by interactions between ligands on circulating tumour cells and endothelial E-selectin adhesion molecules; a process likely to be regulated by the endothelial glycocalyx. Using human cerebral microvascular endothelial cells and non-small cell lung cancer (NSCLC) cell lines, we describe how factors secreted by NSCLC cells i.e. cystatin C, cathepsin L, insulin-like growth factor-binding protein 7 (IGFBP7), vascular endothelial growth factor (VEGF) and tumour necrosis factor-alpha (TNF-α), damage the glycocalyx and enhance initial contacts between lung tumour and cerebral endothelial cells.
  
  
  METHODS
  Endothelial cells were treated with tumour secreted-proteins or lung tumour conditioned medium (CM). Surface levels of E-selectin were quantified by ELISA. Adhesion of A549 and SK-MES-1 cells was examined under flow conditions (1 dyne/cm(2)). Alterations in the endothelial glycocalyx were quantified by binding of fluorescein isothiocyanate-linked wheat germ agglutinin (WGA-FITC).
  
  
  RESULTS
  A549 and SK-MES-1 CM and secreted-proteins significantly enhanced endothelial surface E-selectin levels after 30 min and 4 h and tumour cell adhesion after 30 min, 4 and 24 h. Both coincided with significant glycocalyx degradation; A549 and SK-MES-1 CM removing 55 ± 12 % and 58 ± 18.7 % of WGA-FITC binding, respectively. Inhibition of E-selectin binding by monoclonal anti-E-selectin antibody completely attenuated tumour cell adhesion.
  
  
  CONCLUSIONS
  These data suggest that metastasising lung cancer cells facilitate their own adhesion to the brain endothelium by secreting factors that damage the endothelial glycocalyx, resulting in exposure of the previously shielded adhesion molecules and engagement of the E-selectin-mediated adhesion axis.
authors.affiliation: Institute of Biomedical and Clinical Science, University of Exeter Medical School, St. Luke's campus, Exeter, EX1 2LU, UK. S.Rai@exeter.ac.uk.
authors.forename: Srijana
authors.initials: S
authors.lastname: Rai
authors.affiliation: Institute of Biomedical and Clinical Science, University of Exeter Medical School, St. Luke's campus, Exeter, EX1 2LU, UK. zaynabarya@gmail.com.
authors.forename: Zaynab
authors.initials: Z
authors.lastname: Nejadhamzeeigilani
authors.affiliation: Institute of Biomedical and Clinical Science, University of Exeter Medical School, St. Luke's campus, Exeter, EX1 2LU, UK. N.J.Gutowski@exeter.ac.uk.|Royal Devon and Exeter NHS Foundation Trust, Barrack road, Exeter, EX2 5DW, UK. N.J.Gutowski@exeter.ac.uk.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Gutowski
authors.affiliation: Institute of Biomedical and Clinical Science, University of Exeter Medical School, St. Luke's campus, Exeter, EX1 2LU, UK. J.L.Whatmore@exeter.ac.uk.
authors.forename: Jacqueline L
authors.initials: JL
authors.lastname: Whatmore
mesh_terms: D001921:Brain / Q000098:blood supply* / Q000473:pathology; D001932:Brain Neoplasms / Q000473:pathology / Q000556:secondary*; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology*; D056668:Cathepsin L / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned / Q000494:pharmacology; D055316:Cystatin C / Q000378:metabolism; D019040:E-Selectin / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism; D004730:Endothelium, Vascular / Q000473:pathology; D005434:Flow Cytometry; D019276:Glycocalyx / Q000473:pathology*; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000473:pathology*; D013058:Mass Spectrometry; D055806:Microvessels / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; D017077:Culture Media, Conditioned; D055316:Cystatin C; D019040:E-Selectin; D018969:Insulin-Like Growth Factor Binding Proteins; C546936:SELE protein, human; D014409:Tumor Necrosis Factor-alpha; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C102529:insulin-like growth factor binding protein-related protein 1; D056668:Cathepsin L