Synthesis of a 200-member library of squaric acid N-hydroxylamide amides.

International audienceWe report here the parallel synthesis of 200 compounds based on squaric acid template. These compounds are obtained via a one-step solution-phase procedure starting from three squaric acid N-hydroxylamide esters precursors. The set of diverse reagents qualified (amines, anilines, amino-alcohols and amino-esters) makes this strategy suitable for the search of biologically active compounds. The library was screened on the zinc metalloenzyme ADAMTS-5 and hits with IC(50) in the range of 1-50 microM were identified

Hydroxamates: Relationships between Structure and Plasma Stability

International audienceHydroxamates are valuable tools for chemical biology as well as interesting leads for medicinal chemistry. Though many hydroxamates display nanomolar activities against metalloproteases, only three hydroxamates have reached the market, among which is the HDAC inhibitor vorinostat. Failures in development are generally attributed to lack of selectivity, toxicity or poor stability. To help medicinal chemists with respect to plasma stability, we have performed the first and preliminary study on structure-plasma stability for hydroxamates. We define some structural rules to predict or improve the plasma stability in the preclinical stage

Kinetic Target-Guided Synthesis: Reaching the Age of Maturity

International audienceKinetic target-guided synthesis (KTGS) is an original discovery strategy allowing a target to catalyze the irreversible synthesis of its own ligands from a pool of reagents. Though pioneered almost two decades ago, it only recently proved its usefulness in medicinal chemistry, as exemplified by the increasing number of protein targets used, the wider range of target and pocket types, and the diversity of therapeutic areas explored. In recent years, two new leads for in vivo studies were released. Amidations and multicomponent reactions expanded the armamentarium of reactions beyond triazole formation and two new examples of in cellulo KTGS were also disclosed. Herein, we analyze the origins and the chemical space of both KTGS ligands and warhead-bearing reagents. We review the KTGS timeline focusing on recent cases in order to give medicinal chemists the full scope of this strategy which has great potential for hit discovery and hit or lead optimization

Structure-activity relationships and blood distribution of antiplasmodial aminopeptidase-1 inhibitors

International audienceMalaria is a severe infectious disease that causes between 655 000 and 1.2 million deaths annually. To overcome the resistance to current drugs, new biological targets are needed for drug development. Aminopeptidase M1 (PfAM1), a zinc metalloprotease, has been proposed as a new drug target to fight malaria. Herein, we disclosed the structure–activity relationships of a selective family of hydroxamate PfAM1 inhibitors based on the malonic template. In particular, we performed a “fluoro-scanning” around hit 1 that enlightened the key positions of the halogen for activity. The docking of the best inhibitor 2 is consistent with in vitro results. The stability of 2 was evaluated in microsomes, in plasma, and toward glutathione. The in vivo distribution study performed with the nanomolar hydroxamate inhibitor 2 (BDM14471) revealed that it reaches its site of action. However, it fails to kill the parasite at concentrations relevant to the enzymatic inhibitory potency, suggesting that killing the parasite remains a challenge for potent and druglike catalytic-site binding PfAM1 inhibitors. In all, this study provides important insights for the design of inhibitors of PfAM1 and the validity of this target

Drug Target Engagement using coupled Cellular Thermal Shift Assay -acoustic Reverse Phase Protein Array

International audienceIn the last 5 years, cellular thermal shift assay (CETSA), a technology based on ligand-induced changes in protein thermal stability, has been increasingly used in drug discovery to address the fundamental question of whether drug candidates engage their intended target in a biologically relevant setting. To analyze lysates from cells submitted to increasing temperature, the detection and quantification of the remaining soluble protein can be achieved using quantitative mass spectrometry, Western blotting, or AlphaScreen techniques. Still, these approaches can be time- and cell-consuming. To cope with limitations of throughput and protein amount requirements, we developed a new coupled assay combining the advantages of a nanoacoustic transfer system and reverse-phase protein array technology within CETSA experiments. We validated the technology to assess engagement of inhibitors of insulin-degrading enzyme (IDE), an enzyme involved in diabetes and Alzheimer’s disease. CETSA—acoustic reverse-phase protein array (CETSA-aRPPA) allows simultaneous analysis of many conditions and drug–target engagement with a small sample size, in a rapid, cost-effective, and biological material-saving manner

Controlling Plasma Stability of Hydroxamic Acids: A MedChem Toolbox

International audienceHydroxamic acids are outstanding zinc chelating groups that can be used to design potent and selective metalloenzyme inhibitors in various therapeutic areas. Some hydroxamic acids display a high plasma clearance resulting in poor in vivo activity, though they may be very potent compounds in vitro. We designed a 57-member library of hydroxamic acids to explore the structure-plasma stability relationships in these series and identify both which enzyme(s) and which pharmacophores are critical for plasma stability. Arylesterases and carboxylesterases were identified as the main metabolic enzymes for hydroxamic acids. Finally, we suggest structural features to be introduced or removed to improve stability. This work provides thus the first medicinal chemistry toolbox (experimental procedures and structural guidance) to assess and control the plasma stability of hydroxamic acids and realize their full potential as in vivo pharmacological probes and therapeutic agents. This study is particularly relevant to preclinical development as it allows to obtain compounds equally stable in human and rodent models