title: Rational design of granulocyte-macrophage colony-stimulating factor antagonist peptides.
abstract: Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a member of the four-helix bundle family of cytokines/growth factors which exhibit several activities. It is a hematopoietic growth factor, a cytokine involved in inflammatory and immune processes, an adjunct for cancer therapy, and an anti-tumor immunomodulator. Studies of interactions between GM-CSF and its receptor and identification of small peptides presenting binding capacity to the receptor are important goals for the development of GM-CSF analogs. Here we describe the study of two cyclic peptides, 1785 and 1786, developed based on structural analysis of the GM-CSF region mimicked by anti-anti-GM-CSF recombinant antibody 23.2. These peptides were designed to structurally mimic the positions of specific residues on the B and C helices of human GM-CSF implicated in receptor binding and bioactivity. Both 1785 and 1786 were specifically recognized by polyclonal anti-GM-CSF antibody (stronger for 1786 than 1785). 1786 also competitively inhibited binding of GM-CSF to the GM-CSF receptor on HL-60 cells and demonstrated antagonist bioactivity, as shown by its reversal of GM-CSF's ability to inhibit apoptosis of the GM-CSF-dependent cell line MO7E. These studies support the role of residues on the GM-CSF B and C helices in receptor binding and bioactivity and suggest strategies for mimicking binding sites on four-helix bundle proteins with cyclic peptides.
authors.affiliation: Department of Medicine, Rheumatology Division, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA.
authors.forename: C
authors.initials: C
authors.lastname: Monfardini
authors.forename: T
authors.initials: T
authors.lastname: Kieber-Emmons
authors.forename: D
authors.initials: D
authors.lastname: Voet
authors.forename: A P
authors.initials: AP
authors.lastname: Godillot
authors.forename: D B
authors.initials: DB
authors.lastname: Weiner
authors.forename: W V
authors.initials: WV
authors.lastname: Williams
mesh_terms: D000595:Amino Acid Sequence; D000906:Antibodies; D017209:Apoptosis / Q000187:drug effects; D015195:Drug Design; D004797:Enzyme-Linked Immunosorbent Assay; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D018922:HL-60 Cells; D006801:Humans; D007700:Kinetics; D008961:Models, Structural; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D011869:Radioligand Assay; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins; D013329:Structure-Activity Relationship
chemical_list: D000906:Antibodies; D010456:Peptides, Cyclic; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor