title: Cyclic thrombospondin-1 mimetics: grafting of a thrombospondin sequence into circular disulfide-rich frameworks to inhibit endothelial cell migration.
abstract: Tumour formation is dependent on nutrient and oxygen supply from adjacent blood vessels. Angiogenesis inhibitors can play a vital role in controlling blood vessel formation and consequently tumour progression by inhibiting endothelial cell proliferation, sprouting and migration. The primary aim of the present study was to design cyclic thrombospondin-1 (TSP-1) mimetics using disulfide-rich frameworks for anti-angiogenesis therapies and to determine whether these peptides have better potency than the linear parent peptide. A short anti-angiogenic heptapeptide fragment from TSP-1 (GVITRIR) was incorporated into two cyclic disulfide-rich frameworks, namely MCoTI-II (Momordica cochinchinensis trypsin inhibitor-II) and SFTI-1 (sunflower trypsin inhibitor-1). The cyclic peptides were chemically synthesized and folded in oxidation buffers, before being tested in a series of in vitro evaluations. Incorporation of the bioactive heptapeptide fragment into the cyclic frameworks resulted in peptides that inhibited microvascular endothelial cell migration, and had no toxicity against normal primary human endothelial cells or cancer cells. Importantly, all of the designed cyclic TSP-1 mimetics were far more stable than the linear heptapeptide in human serum. The present study has demonstrated a novel approach to stabilize the active region of TSP-1. The anti-angiogenic activity of the native TSP-1 active fragment was maintained in the new TSP-1 mimetics and the results provide a new chemical approach for the design of TSP-1 mimetics.
authors.affiliation: The University of Queensland, Institute for Molecular Bioscience, Brisbane 4072, Queensland, Australia.
authors.forename: Lai Yue
authors.initials: LY
authors.lastname: Chan
authors.affiliation: The University of Queensland, Institute for Molecular Bioscience, Brisbane 4072, Queensland, Australia norelle.daly@jcu.edu.au d.craik@imb.uq.edu.au.
authors.forename: David J
authors.initials: DJ
authors.lastname: Craik
authors.affiliation: Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns 4870, Queensland, Australia norelle.daly@jcu.edu.au d.craik@imb.uq.edu.au.
authors.forename: Norelle L
authors.initials: NL
authors.lastname: Daly
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000737:chemistry; D032701:Biomimetics / Q000379:methods; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D047169:Cyclotides / Q000008:administration & dosage / Q000737:chemistry; D042783:Endothelial Cells / Q000187:drug effects*; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000737:chemistry; D010456:Peptides, Cyclic / Q000008:administration & dosage / Q000138:chemical synthesis / Q000737:chemistry; D019700:Thrombospondin 1 / Q000138:chemical synthesis / Q000737:chemistry / Q000235:genetics*
chemical_list: D020533:Angiogenesis Inhibitors; D047169:Cyclotides; D010446:Peptide Fragments; D010456:Peptides, Cyclic; C448501:SFTI-1 peptide, sunflower; D019700:Thrombospondin 1; C409923:trypsin inhibitor MCoTI-II
keywords: angiogenesis inhibitors; endothelial cells; non-toxic; peptide; stable; thrombospondin-1