title: Cysteine-rich and basic domain HIV-1 Tat peptides inhibit angiogenesis and induce endothelial cell apoptosis.
abstract: Previous findings suggest that both the Tat polypeptide encoded by HIV-1 and Tat-derived peptides can induce angiogenesis via activation of the KDR receptor for Vascular Endothelial Growth Factor (VEGF). We identified 20 amino acids and 12 amino acid peptides corresponding to the cysteine-rich and basic domains of HIV-1 Tat which inhibited (125)I-VEGF(165) binding to KDR and neuropilin-1 (NP-1) receptors in endothelial cells. Cysteine-rich and basic Tat peptides inhibited VEGF-induced ERK activation and mitogenesis in endothelial cells, and inhibited angiogenesis in vitro at concentrations similar to those which inhibited VEGF receptor binding. These peptides also inhibited proliferation, angiogenesis, and ERK activation induced by basic fibroblast growth factor with similar potency and efficacy. Surprisingly, we found that both cysteine-rich and basic domain Tat peptides strikingly induced apoptosis in endothelial cells, independent of their effects on VEGF and bFGF. Furthermore, we found no evidence for direct biological effects of recombinant Tat on VEGF receptor binding, ERK activation, endothelial cell survival, or mitogenesis. These findings demonstrate novel properties of Tat-derived peptides and indicate that their major effect in endothelial cells is apoptosis independent of specific inhibition of VEGF receptor activation.
authors.affiliation: Department of Medicine, Ark Therapeutics Limited, London, WC1E 6JJ, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Jia
authors.forename: M
authors.initials: M
authors.lastname: Lohr
authors.forename: S
authors.initials: S
authors.lastname: Jezequel
authors.forename: D
authors.initials: D
authors.lastname: Davis
authors.forename: S
authors.initials: S
authors.lastname: Shaikh
authors.forename: D
authors.initials: D
authors.lastname: Selwood
authors.forename: I
authors.initials: I
authors.lastname: Zachary
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D003545:Cysteine / Q000737:chemistry; D016228:Endothelial Growth Factors / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D015696:Gene Products, tat / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D008222:Lymphokines / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000633:toxicity; D017434:Protein Structure, Tertiary; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000187:drug effects / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D016228:Endothelial Growth Factors; D015696:Gene Products, tat; D008222:Lymphokines; D010446:Peptide Fragments; D017978:Receptors, Growth Factor; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016222:Fibroblast Growth Factor 2; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D020928:Mitogen-Activated Protein Kinases; D003545:Cysteine