A novel fragment derived from the beta chain of human fibrinogen, beta43-63, is a potent inhibitor of activated endothelial cells in vitro and in vivo.
BACKGROUND
Angiogenesis and haemostasis are closely linked within tumours with many haemostatic proteins regulating tumour angiogenesis. Indeed we previously identified a fragment of human fibrinogen, fibrinogen E-fragment (FgnE) with potent anti-angiogenic properties in vitro and cytotoxic effects on tumour vessels in vivo. We therefore investigated which region of FgnE was mediating vessel cytotoxicity.


METHODS
Human dermal microvascular endothelial cells (ECs) were used to test the efficacy of peptides derived from FgnE on proliferation, migration, differentiation, apoptosis and adhesion before testing the efficacy of an active peptide on tumour vasculature in vivo.


RESULTS
We identified a 20-amino-acid peptide derived from the beta chain of FgnE, beta43-63, which had no effect on EC proliferation or migration but markedly inhibited the ability of activated ECs to form tubules or to adhere to various constituents of the extracellular matrix - collagen IV, fibronectin and vitronectin. Furthermore, our data show that beta43-63 interacts with ECs, in part, by binding to alpha(v)beta(3), so soluble alpha(v)beta(3) abrogated beta43-63 inhibition of tubule formation by activated ECs. Finally, when injected into mice bearing tumour xenografts, beta43-63 inhibited tumour vascularisation and induced formation of significant tumour necrosis.


CONCLUSIONS
Taken together, these data suggest that beta43-63 is a novel anti-tumour peptide whose anti-angiogenic effects are mediated by alpha(v)beta(3).
Krajewska
E
E
Tumor Targeting Group, University of Sheffield Medical School, Sheffield S10 2RX, UK.
Lewis
C E
CE
Chen
Y-Y
YY
Welford
A
A
Tazzyman
S
S
Staton
C A
CA
D000328:Adult; D000595:Amino Acid Sequence; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects*; D005340:Fibrinogen / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
D020533:Angiogenesis Inhibitors; D010446:Peptide Fragments; D042461:Vascular Endothelial Growth Factor A; D005340:Fibrinogen