Minimal active domain and mechanism of action of the angiogenesis inhibitor histidine-rich glycoprotein

• Histidine-rich glycoprotein (HRGP) is an abundant heparin-binding plasma protein that efficiently arrests growth and vascularization of mouse tumor models. We have shown that the antiangiogenic effect of HRGP is dependent on its histidine/proline-rich domain, which needs to be released from the mother protein to exert its effects. Here we identify a 35-amino-acid peptide, HRGP330, derived from the histidine/proline-rich domain as endowed with antiangiogenic properties in vitro and in vivo. The mechanism of action of HRGP330 involves subversion of focal adhesion function by disruption of integrin-linked kinase (ILK) and focal adhesion kinase (FAK) functions, inhibition of vascular endothelial growth factor (VEGF)-induced tyrosine phosphorylation of the FAK substrate alpha-actinin, and, as a consequence, an arrest in endothelial cell motility. The disturbed focal adhesion function is reflected in the ability of HRGP as well as of HRGP330 to prevent endothelial cell adhesion to vitronectin in a manner involving alpha(v)beta3 integrin. In conclusion, HRGP330, which we define as the minimal antiangiogenic domain of HRGP, exerts its effects through signal transduction targeting focal adhesions, thereby interrupting VEGF-induced endothelial cell motility.

Nyckelord

Actinin/metabolism

Amino Acid Sequence

Animals

Cattle

Cell Movement/drug effects/physiology

Endothelial Cells/cytology/*drug effects

Focal Adhesion Protein-Tyrosine Kinases/metabolism

Integrin alphaVbeta3/metabolism

Molecular Sequence Data

Neovascularization; Physiologic/*drug effects

Paxillin/antagonists & inhibitors/biosynthesis

Peptide Fragments/chemistry/*pharmacology

Phosphorylation/drug effects

Protein Structure; Tertiary

Protein-Serine-Threonine Kinases/metabolism

Proteins/chemistry/*pharmacology

Research Support; Non-U.S. Gov't

Vascular Endothelial Growth Factor A/antagonists & inhibitors/metabolism/pharmacology

Vascular Endothelial Growth Factor Receptor-2/metabolism

MEDICINE

MEDICIN

Publikations- och innehållstyp

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