title: The pseudopeptide HB-19 binds to cell surface nucleolin and inhibits angiogenesis.
abstract: BACKGROUND
  Nucleolin is a protein over-expressed on the surface of tumor and endothelial cells. Recent studies have underlined the involvement of cell surface nucleolin in tumor growth and angiogenesis. This cell surface molecule serves as a receptor for various ligands implicated in pathophysiological processes such as growth factors, cell adhesion molecules like integrins, selectins or laminin-1, lipoproteins and viruses (HIV and coxsackie B). HB-19 is a synthetic multimeric pseudopeptide that binds cell surface expressed nucleolin and inhibits both tumor growth and angiogenesis.
  
  
  RESULTS
  In the present work, we further investigated the biological actions of pseudopeptide HB-19 on HUVECs. In a previous work, we have shown that HB-19 inhibits the in vivo angiogenesis on the chicken embryo CAM assay. We now provide evidence that HB-19 inhibits the in vitro adhesion, migration and proliferation of HUVECs without inducing their apoptosis. The above biological actions seem to be regulated by SRC, ERK1/2, AKT and FAK kinases as we found that HB-19 inhibits their activation in HUVECs. Matrix metalloproteinases (MMPs) play crucial roles in tumor growth and angiogenesis, so we investigated the effect of HB-19 on the expression of MMP-2 and we found that HB-19 downregulates MMP-2 in HUVECs. Finally, down regulation of nucleolin using siRNA confirmed the implication of nucleolin in the biological actions of these peptides.
  
  
  CONCLUSIONS
  Taken together, these results indicate that HB-19 could constitute an interesting tool for tumor therapy strategy, targeting cell surface nucleolin.
authors.affiliation: Department of Biology, University of Patras, Patras, Greece. katsopan@upatras.gr.
authors.forename: Charalampos
authors.initials: C
authors.lastname: Birmpas
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Briand
authors.forename: Josẻ
authors.initials: J
authors.lastname: Courty
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Katsoris