Structure-based discovery of hydrocarbon-stapled paxillin peptides that block FAK scaffolding in cancer

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Therapeutics

Background:

• Focal adhesion kinase (FAK) is a crucial regulator of cancer hallmarks.
• The FAK scaffold, particularly the interaction between its FAT domain and paxillin, is key to its function.
• Targeting protein-protein interactions offers a promising therapeutic avenue.

Purpose of the Study:

• To design and validate paxillin LD-motif mimetics to inhibit the FAK-paxillin interaction.
• To develop a novel therapeutic strategy against the previously undruggable FAK-paxillin complex.

Main Methods:

• Design and synthesis of paxillin LD-motif mimetics.
• Chemical and biochemical screening to identify high-affinity binders.
• X-ray crystallography to determine the co-crystal structure of the FAT-1907 complex.
• In vitro and in vivo studies using cancer cell lines and mouse models.

Main Results:

• Stapled peptide 1907 demonstrated high affinity for the FAT four-helix bundle, significantly exceeding native binding.
• A myristoylated analog, peptide 2012, effectively delocalized FAK, induced apoptosis, and reduced cancer cell viability and invasion.
• Peptide 2012 significantly decreased tumor burden in a B16F10 melanoma mouse model.
• Enzymatic FAK inhibition did not yield comparable therapeutic effects.

Conclusions:

• The FAK-paxillin interaction can be effectively targeted using designed peptide mimetics.
• This strategy represents a potent therapeutic approach for cancers driven by FAK signaling.
• Targeting protein-protein interactions like FAK-paxillin is a viable strategy for cancer therapy.