Maryanna E. Lanning

Amphipathic α-helix mimetics based on a 1,2-diphenylacetylene scaffold.

In order to mimic amphipathic α-helices, a novel scaffold based on a 1,2-diphenylacetylene was designed. NMR and computational modeling confirmed that an intramolecular hydrogen bond favors conformations of the 1,2-diphenylacetylene that allow for accurate mimicry of the i, i + 7 and i + 2, i + 5 side chains found on opposing faces of an α-helix.

Structural modifications of (Z)-3-(2-aminoethyl)-5-(4-ethoxybenzylidene)thiazolidine-2,4-dione that improve selectivity for inhibiting the proliferation of melanoma cells containing active ERK signaling

We herein report on the pharmacophore determination of the ERK docking domain inhibitor (Z)-3-(2-aminoethyl)-5-(4-ethoxybenzylidene)thiazolidine-2,4-dione, which has led to the discovery of compounds with greater selectivities for inhibiting the proliferation of melanoma cells containing active ERK signaling.

Structure-based design of N-substituted 1-hydroxy-4-sulfamoyl-2-naphthoates as selective inhibitors of the Mcl-1 oncoprotein.

Structure-based drug design was utilized to develop novel, 1-hydroxy-2-naphthoate-based small-molecule inhibitors of Mcl-1. Ligand design was driven by exploiting a salt bridge with R263 and interactions with the p2 pocket of the protein. Significantly, target molecules were accessed in just two synthetic steps, suggesting further optimization will require minimal synthetic effort. Molecular modeling using the Site-Identification by Ligand Competitive Saturation (SILCS) approach was used to qualitatively direct ligand design as well as develop quantitative models for inhibitor binding affinity to Mcl-1 and the Bcl-2 relative Bcl-xL as well as for the specificity of binding to the two proteins. Results indicated hydrophobic interactions in the p2 pocket dominated affinity of the most favourable binding ligand (3bl: Ki = 31 nM). Compounds were up to 19-fold selective for Mcl-1 over Bcl-xL. Selectivity of the inhibitors was driven by interactions with the deeper p2 pocket in Mcl-1 versus Bcl-xL. The SILCS-based SAR of the present compounds represents the foundation for the development of Mcl-1 specific inhibitors with the potential to treat a wide range of solid tumours and hematological cancers, including acute myeloid leukemia.

Chromatography-Free Entry to Substituted Salicylonitriles: Mitsunobu-Triggered Domino Reactions of Salicylaldoximes

A mild and efficient one-pot procedure is described to transform salicylaldoximes into salicylonitriles using Mitsunobu chemistry. The reactions proceed through the corresponding 1,2-benzisoxazoles that undergo the Kemp elimination in situ to generate the target salicylonitriles in excellent yields. The chemistry exhibits a broad scope, and the salicylonitriles can be readily isolated by a simple acid-base workup. In addition to functioning as useful synthetic precursors, salicylonitriles may serve as more cell penetrable bioisosteres of carboxylic acids.

Recapitulating the α-helix: nonpeptidic, low-molecular-weight ligands for the modulation of helix-mediated protein–protein interactions

Protein-protein interactions play critical roles in a wide variety of biological processes, and their dysregulations contribute to the pathogenesis of several diseases, including cancer. Chemical entities that can abrogate aberrant protein-protein interactions may provide novel therapeutic agents. A large number of protein-protein interactions are mediated by protein secondary structure, the most commonly encountered form of which is the α-helix. Accordingly, over the last decade, there has been a flood of nonpeptidic small molecules that recapitulate the projection and chemical nature of key side chains of the canonical α-helix as a strategy to disrupt helix-mediated protein-protein interactions. In this review, we discuss recent advances (post 2006) in the design of synthetic α-helix mimetics, which include single-faced and two-faced/amphipathic structures, for the modulation of protein-protein interactions.

Structural Re-engineering of the α-Helix Mimetic JY-1-106 into Small Molecules: Disruption of the Mcl-1-Bak-BH3 Protein-Protein Interaction with 2,6-Di-Substituted Nicotinates.

The disruption of aberrant protein–protein interactions (PPIs) with synthetic agents remains a challenging goal in contemporary medicinal chemistry but some progress has been made. One such dysregulated PPI is that between the anti‐apoptotic Bcl‐2 proteins, including myeloid cell leukemia‐1 (Mcl‐1), and the α‐helical Bcl‐2 homology‐3 (BH3) domains of its pro‐apoptotic counterparts, such as Bak. Herein, we describe the discovery of small‐molecule inhibitors of the Mcl‐1 oncoprotein based on a novel chemotype. Particularly, re‐engineering of our α‐helix mimetic JY‐1‐106 into 2,6‐di‐substituted nicotinates afforded inhibitors of comparable potencies but with significantly decreased molecular weights. The most potent inhibitor 2‐(benzyloxy)‐6‐(4‐chloro‐3,5‐dimethylphenoxy)nicotinic acid (1 r: Ki=2.90 μm) likely binds in the p2 pocket of Mcl‐1 and engages R263 in a salt bridge through its carboxylic acid, as supported by 2D 1H–15N HSQC NMR data. Significantly, inhibitors were easily accessed in just four steps, which will facilitate future optimization efforts.

Multi-Facial, Non-Peptidic α-Helix Mimetics.

α-Helices often recognize their target proteins at protein–protein interfaces through more than one recognition face. This review describes the state-of-the-art in the design of non-peptidic α-helix mimetics that reproduce functionality from multiple faces of an α-helix.