Isoquinolin‐1‐one Inhibitors of the MDM2–p53 Interaction

Abstract

p53 has been at the centre of attention for drug design since the discovery of its growth-suppressive and pro-apoptotic activity. Herein we report the design and characterisation of a new class of isoquinolinone inhibitors of the MDM2-p53 interaction. Our identification of druglike and selective inhibitors of this protein-protein interaction included a straightforward in silico compound-selection process, a recently reported NMR spectroscopic approach for studying the MDM2-p53 interaction, and selectivity screening assays using cells with the same genetic background. The selected inhibitors were all able to induce apoptosis and the expression of p53-related genes, but only the isoquinolin-1-one-based inhibitors stabilised p53. Our NMR experiments give a persuading explanation for these results, showing that isoquinolin-1-one derivates are able to dissociate the preformed MDM2-p53 complex in vitro, releasing a folded and soluble p53. The joint application of these methods provides a framework for the discovery of protein interaction inhibitors as a promising starting point for further drug design.

NMR Spectroscopy for Studying Interactions of Bioactive Molecules

“…Although modern ligand-based NMR methods are most widely used to monitor ligand-protein interactions, standard one-and two-dimensional NMR methods are able to structurally characterise the investigated ligand-protein complexes [96][97][98]. Alcaraz et al [99] used 13 C NOESY-HSQC spectra to characterise the adducts of the catalytic domain of matrix metalloprotease-3 (MMP3) with three different non-peptide inhibitors.…”

Enabling Large-Scale Design, Synthesis and Validation of Small Molecule Protein-Protein Antagonists

“…Although not common in existing compound libraries, MCR compounds are well represented among known small-molecule PPI inhibitors [16], [17], [18]. More importantly, MCR derived peptido-mimetic chemotypes allow us to design compound libraries that include chemical mimics of key amino acids important for molecular recognition [19].…”

NMR Screening and Hit Validation in Fragment Based Drug Discovery

“…Some other methods for screening are also based on monitoring only a small part of the protein NMR spectrum. Thus, a simple method consists of introducing, by site directed mutagenesis, tryptophan residues in 3D structure-guided positions (without affecting ligand binding), and monitoring the binding through the well-dispersed signals of the Trp NH indole in 1D 1 H spectra [68], as recently reported to study Mdm2-p53 interaction blockers [69] and cdk2 inhibitors. Previous work also used selective 13 C labeling of native Trp residues at single sidechain positions [70].…”