title: Characterization of ATP-independent ERK inhibitors identified through in silico analysis of the active ERK2 structure.
abstract: The extracellular signal-regulated kinases (ERK1 and ERK2) are important mediators of cell proliferation. Constitutive activation of the ERK proteins plays a critical role in the proliferation of many human cancers. Taking advantage of recently identified substrate docking domains on ERK2, we have used computer-aided drug design (CADD) to identify novel low molecular weight compounds that interact with ERK2 in an ATP-independent manner and disrupt substrate-specific interactions. In the current study, a CADD screen of the 3D structure of active phosphorylated ERK2 protein was used to identify inhibitory compounds. We tested 13 compounds identified by the CADD screen in ERK-specific phosphorylation, cell proliferation, and binding assays. Of the 13 compounds tested, 4 compounds strongly inhibited ERK-mediated phosphorylation of ribosomal S6 kinase-1 (Rsk-1) and/or the transcription factor Elk-1 and inhibited the proliferation of HeLa cervical carcinoma cells with IC(50) values in the 2-10 microM range. These studies demonstrate that CADD can be used to identify lead compounds for development of novel non-ATP-dependent inhibitors selective for active ERK and its interactions with substrates involved in cancer cell proliferation.
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA.
authors.forename: Fengming
authors.initials: F
authors.lastname: Chen
authors.forename: Chad N
authors.initials: CN
authors.lastname: Hancock
authors.forename: Alba T
authors.initials: AT
authors.lastname: Macias
authors.forename: Joseph
authors.initials: J
authors.lastname: Joh
authors.forename: Kimberly
authors.initials: K
authors.lastname: Still
authors.forename: Shijun
authors.initials: S
authors.lastname: Zhong
authors.forename: Alexander D
authors.initials: AD
authors.lastname: MacKerell
authors.forename: Paul
authors.initials: P
authors.lastname: Shapiro
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D001665:Binding Sites; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3