Inhibiting Epidermal Growth Factor Receptor at a Distance

Abstract

The epidermal growth factor receptor (EGFR) tyrosine kinase is implicated in a large number of human cancers. Most EGFR inhibitors target the extracellular, growth factor-binding domain or the intracellular, ATP-binding domain. Here we describe molecules that inhibit the kinase activity of EGFR in a new way, by competing with formation of an essential intradimer coiled coil containing the juxtamembrane segment from each member of the receptor partnership. The most potent molecules we describe bind EGFR directly, decrease the proliferation of wild-type and mutant EGFR-dependent cells lines, inhibit phosphorylation of EGFR and downstream targets, and block coiled coil formation as judged by bipartite tetracysteine display. Potency is directly correlated with the ability to block coiled coil formation within full-length EGFR in cells.

Growth Factor Identity Is Encoded by Discrete Coiled-Coil Rotamers in the EGFR Juxtamembrane Region

“…Preliminary disulfide exchange and circular dichroism spectroscopy experiments revealed that peptides containing the minimal JM-A segment (residues 650 to 666) do not appreciably form dimers at concentrations below 150 µM (Scheck et al, 2012; Sinclair et al, 2014) precluding a straightforward biophysical analysis of the isolated peptides. Thus, we turned to an in silico analysis to explore the diversity of the JM-A conformational landscape in the absence of complicating oligomerization events and then used bipartite tetracysteine display to detect these diverse conformations in the context of the intact receptor.…”

Stapled peptide design: principles and roles of computation

“…Challenging targets, such as transcription factors, which were thought to be undruggable, have been successfully inhibited by stapled peptides [25,26]. It has also been shown that stapled peptides are able to disrupt enzyme [27], multidrug resistance efflux pump [28] and membrane receptor [29] dimers, thus opening new possibilities for targeting traditional drug targets, which is becoming especially important because of the development of resistance against current drugs.…”

Influence of Macrocyclization on Allosteric, Juxtamembrane-Derived, Stapled Peptide Inhibitors of the Epidermal Growth Factor Receptor (EGFR)

“…1 The stapled peptide E1 S caused a dose-dependent decrease in EGFR autophosphorylation at several positions within the C-terminal tail. E1 S inhibited phosphorylation at Y845, Y1045, Y1086, and Y1173, but not Y1068 and Y1148.…”

“…1 Helical wheel representation of (B) unstapled alkene precursors to previously reported hydrocarbon-stapled peptides E1 S , E2 S , E4 S , T1 S , and T4 S and (C) three new, stapled variants of E1 S .…”