Stapled Peptides for Protein Interaction Research and Therapeutic Targeting in Human Cancer

PROJECT SUMMARY / ABSTRACT
Deregulated protein interactions contribute to the development, maintenance, and chemoresistance of human
cancer. The critical contact points of cancer-causing proteins are often mediated by so-called “helix-in-groove”
interactions, whereby an alpha-helical subcomponent of one protein inserts into the surface groove of another
to drive oncogenic signaling. For example, BCL-2 family proteins regulate the critical balance between cellular
life and death and cancer cells overexpress the anti-apoptotic members, which contain a surface groove that
effectively traps the “killer” helix of pro-apoptotic members, to enforce cellular immortality. We have inserted all-
hydrocarbon struts into natural alpha-helices to restore their shape, stability, and bioactivity so that they can be
used as both powerful chemical tools to dissect oncogenic protein interactions and as prototype therapeutics to
drug them. Over the last 15 years, I have developed special expertise in the design of stapled peptides for
diverse applications in cancer research and treatment. I have generated spin-labeled analogs for NMR structural
analyses, photoreactive constructs for rapid binding-site analysis by mass spectrometry, cysteine-reactive
variants for covalent targeting of oncogenic proteins, fluorescent derivatives for binding affinity quantitation and
cellular imaging, radiolabeled constructs for in vivo imaging, and iteratively-optimized analogs for preclinical
testing and translation. The remarkable impact of stapled peptides is best reflected by their capacity to identify
new cancer targets, mechanisms, and druggable binding sites and their advancement to clinical trials in adults
and children with relapsed cancers. The goal of this competitive renewal application is to continue to expand the
breadth and depth of stapled peptide innovation in support of critical cancer research programs that harness
these reagents in proteomic discovery, structural determination, mechanism-of-action studies, and therapeutic
development. Specifically, I aim to robustly support the NCI-funded R35 research program of my Unit Director,
Dr. Loren Walensky, who as a chemical biologist and pediatric oncologist, focuses on characterizing the BCL-2
family interaction mechanisms that drive human cancer by neutralizing the mitochondrial apoptosis pathway.
Reactivating apoptosis in cancer is essential to overcoming chemoresistance and the pathologic alpha-helical
interactions of the BCL-2 family are ideally suited for interrogation by stapled peptides. In running the Stapled
Peptide Design Group of the Walensky lab and Dana-Farber’s Program in Cancer Chemical Biology, I am
personally responsible for developing and optimizing the chemistry that drives stapled peptide innovations, and
creating a high-throughput consultation, production, purification, quantitation, and characterization workflow that
is also relied upon by dozens of our internal and external collaborators. As a Research Specialist operating at
the interface of chemistry, cancer biology, and experimental therapeutics, I am committed to mining the potential
of next-generation stapled peptides to advance our understanding of fundamental oncogenic mechanisms and
to create novel therapeutics for cancer treatment.

Grant Number: 5R50CA211399-10
NIH Institute/Center: NIH
Principal Investigator: Gregory Bird