A Novel Class of Common Docking Domain Inhibitors That Prevent ERK2 Activation and Substrate Phosphorylation.

Abstract

Extracellular signal-regulated kinases (ERK1/2) are mitogen-activated protein kinases (MAPKs) that play a pro-tumorigenic role in numerous cancers. ERK1/2 possess two protein-docking sites that are distinct from the active site: the D-recruitment site (DRS) and the F-recruitment site. These docking sites facilitate substrate recognition, intracellular localization, signaling specificity, and protein complex assembly. Targeting these sites on ERK in a therapeutic context may overcome many problems associated with traditional ATP-competitive inhibitors. Here, we identified a new class of inhibitors that target the ERK DRS by screening a synthetic combinatorial library of more than 30 million compounds. The screen detects the competitive displacement of a fluorescent peptide from the DRS of ERK2. The top molecular scaffold from the screen was optimized for structure-activity relationship by positional scanning of different functional groups. This resulted in 10 compounds with similar binding affinities and a shared core structure consisting of a tertiary amine hub with three functionalized cyclic guanidino branches. Compound 2507-1 inhibited ERK2 from phosphorylating a DRS-targeting substrate and prevented the phosphorylation of ERK2 by a constitutively active MEK1 (MAPK/ERK kinase 1) mutant. Interaction between an analogue, 2507-8, and the ERK2 DRS was confirmed by nuclear magnetic resonance and X-ray crystallography. 2507-8 forms critical interactions at the common docking domain residue Asp319 via an arginine-like moiety that is shared by all 10 hits, suggesting a common binding mode. The structural and biochemical insights reported here provide the basis for developing new ERK inhibitors that are not ATP-competitive but instead function by disrupting critical protein-protein interactions.

• Authors: Rachel M Sammons, Nicole A Perry, Yangmei Li, Eun Jeong Cho, Andrea Piserchio, Diana P Zamora-Olivares, Ranajeet Ghose, Tamer S Kaoud, Ginamarie Debevec, Chandra Bartholomeusz, Vsevolod V Gurevich, Tina M Iverson, Marc Giulianotti, Richard A Houghten, Kevin N Dalby
• Journal: ACS chemical biology (ACS Chem Biol) Vol. 14 Issue 6 Pg. 1183-1194 (06 21 2019) ISSN: 1554-8937 [Electronic] United States
• PMID: 31058487 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Protein Kinase Inhibitors
• MAPK1 protein, human
• Mitogen-Activated Protein Kinase 1
• Guanidine

Topics

• Binding Sites
• Crystallography, X-Ray
• Dose-Response Relationship, Drug
• Enzyme Activation
• Guanidine (pharmacology)
• Humans
• Mitogen-Activated Protein Kinase 1 (antagonists & inhibitors, chemistry, metabolism)
• Nuclear Magnetic Resonance, Biomolecular
• Phosphorylation
• Protein Kinase Inhibitors (pharmacology)
• Substrate Specificity