Antiangiogenic activity of a domain deletion mutant of tissue plasminogen activator containing kringle 2.
OBJECTIVE
The thrombolytic therapy drug, Reteplase, is a domain deletion mutant of tissue plasminogen activator (tPA), comprising the kringle 2 and protease (K2P) domains. Some kringle domains of hemostatic proteins are antiangiogenic and promote apoptosis. The objective of this study was to investigate whether K2P is an angiogenesis inhibitor because of the presence of kringle 2.


RESULTS
K2P inhibited basic fibroblast growth factor-induced human endothelial cell proliferation and migration. Inhibition was not dependent on the protease activity of K2P because similar results were obtained with catalytically inactivated K2P. Purification of the kringle 2 domain derived from elastase cleavage of K2P at the Arg275-Ile276 bond revealed that inhibition was mediated by this domain. In addition, K2P inhibited angiogenesis in vivo and increased endothelial cell apoptosis.


CONCLUSIONS
Wound healing and angiogenesis are severely compromised by K2P. These data provide new mechanistic insights into the bleeding complications observed in some patients while undergoing thrombolytic therapy with this drug. In addition, we identify the kringle 2 domain of tPA as a novel target for antiangiogenic therapy.
Carroll
Veronica A
VA
Molecular Oncology Laboratory, Cancer Research UK, the Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK.
Nikitenko
Leonid L
LL
Bicknell
Roy
R
Harris
Adrian L
AL
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology; D017353:Gene Deletion; D006801:Humans; D018082:Kringles / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology*; D010196:Pancreatic Elastase / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology*; D014945:Wound Healing / Q000502:physiology
D010446:Peptide Fragments; D011994:Recombinant Proteins; C087896:reteplase; D012697:Serine Endopeptidases; D010196:Pancreatic Elastase; D010959:Tissue Plasminogen Activator