The goal of this project is to identify small ligands which may be used to specifically deliver cytotoxic compounds to breast tumor cells. Ligands much smaller than antibody fragments may have important advantages in targeted cancer therapy including improvement of tumor to nontumor ratios of ligand binding, better penetration of solid tumors, and non-immunogenicity. This proposal describes the use of random peptide library technologies, which have revolutionized the drug discovery process, to identify small ligands to tumor-specific targets. These ligands can then be coupled to cytotoxic agents and used to mediate the specific destruction of tumor cells. Our primary target is the extracellular domain (ECD) of ErbB2, a promising breast cancer tumor-specific target found on the cell surface of the tumor cells of at least 30 percent of breast cancer patients and, importantly, associated with a poor prognosis. Using an ErbB2 dimerization assay we have developed, we will also attempt to identify peptides which inhibit dimerization. Such peptides may have therapeutic value, even without coupling to cytotoxic agents. Several consensus amino acid sequences which may bind to ErbB2 have been identified by extensive screening with a peptide library we constructed, although the affinity of these peptides was not high enough to allow unequivocal proof of their specificity. Peptide library technology has evolved rapidly, and it has become apparent that one library is not adequate to obtain high affinity binders to any given target. A large panel of libraries which present a vast number of peptides presented in a variety of structural contexts is much more likely to yield a high affinity binder.
The Specific Aims of this project are to: (1) Construct a large panel of random peptide libraries (2) Identify and characterize displayed peptide binders to ErbB2 ECD (3) Synthesize and characterize free peptides which bind to ErbB2 ECD (4) Construct mutagenesis libraries and/or synthesize peptidomimetics using identified consensus sequences to increase the affinity and/or stability of peptide ligands (5) Identify and further characterize small ligands to other promising tumor targets. This project will result in the identification of tumor-specific ligands with the affinity and specificity of antibodies but with the more favorable pharmacokinetics of low molecular weight drugs. Specifically, this work will produce lead compounds for drugs with great potential efficacy in the treatment of breast cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA080790-03
Application #
6377054
Study Section
Experimental Therapeutics Subcommittee 1 (ET)
Program Officer
Forry, Suzanne L
Project Start
1999-04-15
Project End
2003-03-31
Budget Start
2001-04-01
Budget End
2003-03-31
Support Year
3
Fiscal Year
2001
Total Cost
$304,985
Indirect Cost
Name
University of Vermont & St Agric College
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Boivin, Benoit; Chaudhary, Fauzia; Dickinson, Bryan C et al. (2013) Receptor protein-tyrosine phosphatase ? regulates focal adhesion kinase phosphorylation and ErbB2 oncoprotein-mediated mammary epithelial cell motility. J Biol Chem 288:36926-35
Giricz, Orsi; Calvo, Veronica; Pero, Stephanie C et al. (2012) GRB7 is required for triple-negative breast cancer cell invasion and survival. Breast Cancer Res Treat 133:607-15
Ambaye, Nigus D; Pero, Stephanie C; Gunzburg, Menachem J et al. (2011) Structural basis of binding by cyclic nonphosphorylated peptide antagonists of Grb7 implicated in breast cancer progression. J Mol Biol 412:397-411
Pero, S C; Shukla, G S; Cookson, M M et al. (2007) Combination treatment with Grb7 peptide and Doxorubicin or Trastuzumab (Herceptin) results in cooperative cell growth inhibition in breast cancer cells. Br J Cancer 96:1520-5
Tanaka, Shinji; Pero, Stephanie C; Taguchi, Kenichi et al. (2006) Specific peptide ligand for Grb7 signal transduction protein and pancreatic cancer metastasis. J Natl Cancer Inst 98:491-8
Shukla, Girja S; Krag, David N (2006) Selective delivery of therapeutic agents for the diagnosis and treatment of cancer. Expert Opin Biol Ther 6:39-54
Shukla, Girja S; Krag, David N (2005) Selection of tumor-targeting agents on freshly excised human breast tumors using a phage display library. Oncol Rep 13:757-64
Shukla, Girja S; Krag, David N (2005) A sensitive and rapid chemiluminescence ELISA for filamentous bacteriophages. J Immunoassay Immunochem 26:89-95
Shukla, Girja S; Krag, David N (2005) Phage display selection for cell-specific ligands: development of a screening procedure suitable for small tumor specimens. J Drug Target 13:7-18
Pero, Stephanie C; Shukla, Girja S; Armstrong, Amy L et al. (2004) Identification of a small peptide that inhibits the phosphorylation of ErbB2 and proliferation of ErbB2 overexpressing breast cancer cells. Int J Cancer 111:951-60