Optimisation and characterisation of cyclic peptides targeting the Grb7 SH2 domain — ASN Events
  1. Schedule
  2. Session 10: Poster Session C
  3. Optimisation and characterisation of cyclic peptides targeting the Grb7 SH2 domain

Optimisation and characterisation of cyclic peptides targeting the Grb7 SH2 domain (#340)

Gabrielle Watson 1 , Menachem Gunzburg 1 , Ketav Kulkarni 1 2 , Katie Cergol 3 , Richard Payne 3 , Patrick Perlmutter 2 , Matthew Wilce 1 , Jackie Wilce 1
  1. Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
  2. Department of Chemistry, Monash University, Clayton, VIC
  3. Department of Chemistry, University of Sydney, Darlington, NSW

A fundamental characteristic of cancerous cells is their ability to sustain proliferative signalling. Targeting deregulated signalling pathways is a common strategy when developing anti-cancer therapeutics. Patients have improved outcomes following multi-drug therapy; therefore, there is a continual need to develop anti-cancer agents. Human growth factor receptor bound protein 7 (Grb7) is an adaptor protein that relays signals from a variety of substrates, including phosphorylated growth factor receptor tyrosine kinases. Grb7 is overexpressed in a multitude of cancers, particularly pancreatic and breast cancer, and has an established role in cancer cell proliferation and migration1,2.

A non-phosphorylated cyclic peptide, G7-18NATE, has been shown to inhibit pancreatic cell migration, and reduce cellular growth and migration in breast cancer cell lines2,3. The peptide binds to the Grb7 SH2 domain with moderate affinity4; therefore, to improve on this, rational adjustments adjustment through structural analysis has lead to a G7-18NATE derivative with a carboxymethylphenylalanine substitution. Initial experiments using SPR have shown the derivative, G7-TEM, has a 5-fold increased affinity for the Grb7 SH2 domain compared with G7-18NATE. Importantly, the derivative also maintains target specificity. The basis for the increased affinity has been identified using x-ray crystallography, and centres around additional protein-peptide interactions in the Grb7 phosphotyrosine binding pocket. 

Developing and characterising G7-TEM and further G7-18NATE derivatives will establish fundamental methods that can be readily applied to other intracellular therapeutic targets as well as mark considerable progress in Grb7 based anti-cancer drug development.

  1. Stein, D., Wu, J., Fuqua, S.A., Roonprapunt, C., Yajnik, V., D’Eustachio, P., Moskow, J., Buchberg, A.M., Osborne, C.K. and Margolis, B. (1994) The SH2 domain protein GRB-7 is co-amplified, overexpressed and in a tight complex with HER2 in breast cancer. EMBO J. 13, 1331
  2. Tanaka, S., Pero, S.C., Taguchi, K., Shimada, M., Mori, M., Krag, D.N., and Arii, S. (2006) Specific peptide ligand for Grb7 signal transduction protein and pancreatic cancer metastasis. J. Natl. Cancer Inst. 98, 491
  3. Pero, S.C., Shukla, G.S., Cookson, M. M., Flemer, S., and Krag, D.N. (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
  4. Gunzburg, M.J., Ambaye, N.D., Del Borgo, M.P., Pero, S.C., Krag, D.N., Wilce, M.C., Wilce, J.A. (2012) Interaction of the non-phosphorylated peptide G7-18NATE with Grb7-SH2 domain requires phosphate for enhanced affinity and specificity. J. Mol. Recognit. 25, 57