Anne Marie Jeanne Bouillot

Discovery and Characterization of Small Molecule Inhibitors of the Bet Family Bromodomains.

Epigenetic mechanisms of gene regulation have a profound role in normal development and disease processes. An integral part of this mechanism occurs through lysine acetylation of histone tails which are recognized by bromodomains. While the biological and structural characterization of many bromodomain containing proteins has advanced considerably, the therapeutic tractability of this protein family is only now becoming understood. This paper describes the discovery and molecular characterization of potent (nM) small molecule inhibitors that disrupt the function of the BET family of bromodomains (Brd2, Brd3, and Brd4). By using a combination of phenotypic screening, chemoproteomics, and biophysical studies, we have discovered that the protein-protein interactions between bromodomains and acetylated histones can be antagonized by selective small molecules that bind at the acetylated lysine recognition pocket. X-ray crystal structures of compounds bound into bromodomains of Brd2 and Brd4 elucidate the molecular interactions of binding and explain the precisely defined stereochemistry required for activity.

Identification of a novel series of BET family bromodomain inhibitors: binding mode and profile of I-BET151 (GSK1210151A).

A novel series of quinoline isoxazole BET family bromodomain inhibitors are discussed. Crystallography is used to illustrate binding modes and rationalize their SAR. One member, I-BET151 (GSK1210151A), shows good oral bioavailability in both the rat and minipig as well as demonstrating efficient suppression of bacterial induced inflammation and sepsis in a murine in vivo endotoxaemia model.

From ApoA1 upregulation to BET family bromodomain inhibition: discovery of I-BET151.

The discovery, synthesis and biological evaluation of a novel series of 7-isoxazoloquinolines is described. Several analogs are shown to increase ApoA1 expression within the nanomolar range in the human hepatic cell line HepG2.

SCAP ligands are potent new lipid-lowering drugs

Upregulation of low-density lipoprotein receptor (LDLr) is a key mechanism to control elevated plasma LDL-cholesterol levels. Here we identify a new class of compounds that directly binds to the sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP). We show that a 14C-labeled, photo-activatable analog specifically labeled both SCAP and a truncated form of SCAP containing the sterol-sensing domain. When administered to hyperlipidemic hamsters, SCAP ligands reduced both LDL cholesterol and triglycerides levels by up to 80% with a three-fold increase in LDLr mRNA in the livers. Using human hepatoma cells, we show that these compounds act through the sterol-responsive element of the LDLr promoter and activate the SCAP/SREBP pathway, leading to increased LDLr expression and activity, even in presence of excess of sterols. These findings have led to the identification of a class of compounds that represent a promising new class of hypolipidemic drugs.

Pharmacological inhibition of stearoyl-CoA desaturase 1 improves insulin sensitivity in insulin-resistant rat models.

Stearoyl-CoA Desaturase 1 (SCD1) is a central enzyme that catalyzes the biosynthesis of monounsaturated fatty acids from saturated fatty acids. SCD1 is an emerging target in obesity and insulin resistance due to the improved metabolic profile obtained when the enzyme is genetically inactivated. Here, we have investigated if the pharmacological inhibition of SCD1 could elicit the same profile. We have identified a small molecule, GSK993 and characterized it as a potent and orally available SCD1 inhibitor. In Zucker(fa/fa) rats, GSK993 exerted a marked reduction in hepatic lipids as well as a significant improvement of glucose tolerance. Furthermore, in a diet-induced insulin resistant rat model, GSK993 induced a very strong reduction in Triton-induced hepatic Very Low Density Lipoprotein-Triglyceride production. In addition, following a hyperinsulinemic-euglycemic clamp in GSK993-treated animals, we observed an improvement in the whole body insulin sensitivity as reflected by an increase in the glucose infusion rate. Taken together, these findings demonstrate that the pharmacological inhibition of SCD1 translates into improved lipid and glucose metabolic profiles and raises the interest of SCD1 inhibitors as potential new drugs for the treatment of insulin resistance.

Naphthyridines as Novel Bet Family Bromodomain Inhibitors.

Bromodomains (BRDs) are small protein domains found in a variety of proteins that recognize and bind to acetylated histone tails. This binding affects chromatin structure and facilitates the localisation of transcriptional complexes to specific genes, thereby regulating epigenetically controlled processes including gene transcription and mRNA elongation. Inhibitors of the bromodomain and extra‐terminal (BET) proteins BRD2–4 and T, which prevent bromodomain binding to acetyl‐modified histone tails, have shown therapeutic promise in several diseases. We report here the discovery of 1,5‐naphthyridine derivatives as potent inhibitors of the BET bromodomain family with good cell activity and oral pharmacokinetic parameters. X‐ray crystal structures of naphthyridine isomers have been solved and quantum mechanical calculations have been used to explain the higher affinity of the 1,5‐isomer over the others. The best compounds were progressed in a mouse model of inflammation and exhibited dose‐dependent anti‐inflammatory pharmacology.

Comparison of Soluble Guanylate Cyclase Stimulators and Activators in Models of Cardiovascular Disease Associated with Oxidative Stress

Soluble guanylate cyclase (sGC), the primary mediator of nitric oxide (NO) bioactivity, exists as reduced (NO-sensitive) and oxidized (NO-insensitive) forms. We tested the hypothesis that the cardiovascular protective effects of NO-insensitive sGC activation would be potentiated under conditions of oxidative stress compared to those of NO-sensitive sGC stimulation. The cardiovascular effects of the NO-insensitive sGC activator GSK2181236A [a low, non-depressor dose, and a high dose which lowered mean arterial pressure (MAP) by 5–10 mmHg] and those of equi-efficacious doses of the NO-sensitive sGC stimulator BAY 60-4552 were assessed in (1) Sprague Dawley rats during coronary artery ischemia/reperfusion (I/R) and (2) spontaneously hypertensive stroke prone rats (SHR-SP) on a high salt/fat diet (HSFD). In I/R, neither compound reduced infarct size 24 h after reperfusion. In SHR-SP, HSFD increased MAP, urine output, microalbuminuria, and mortality, caused left ventricular hypertrophy with preserved ejection fraction, and impaired endothelium-dependent vasorelaxation. The low dose of BAY 60-4552, but not that of GSK2181236A, decreased urine output, and improved survival. Conversely, the low dose of GSK2181236A, but not that of BAY 60-4552, attenuated the development of cardiac hypertrophy. The high doses of both compounds similarly attenuated cardiac hypertrophy and improved survival. In addition to these effects, the high dose of BAY 60-4552 reduced urine output and microalbuminuria and attenuated the increase in MAP to a greater extent than did GSK2181236A. Neither compound improved endothelium-dependent vasorelaxation. In SHR-SP isolated aorta, the vasodilatory responses to the NO-dependent compounds carbachol and sodium nitroprusside were attenuated by HSFD. In contrast, the vasodilatory responses to both GSK2181236A and BAY 60-4552 were unaltered by HSFD, indicating that reduced NO-bioavailability and not changes in the oxidative state of sGC is responsible for the vascular dysfunction. In summary, GSK2181236A and BAY 60-4552 provide partial benefit against hypertension-induced end-organ damage. The differential beneficial effects observed between these compounds could reflect tissue-specific changes in the oxidative state of sGC and might help direct the clinical development of these novel classes of therapeutic agents.

Design and evaluation of a novel series of 2,3-oxidosqualene cyclase inhibitors with low systemic exposure, relationship between pharmacokinetic properties and ocular toxicity.

We describe the discovery of novel potent inhibitors of 2,3-oxidosqualene:lanosterol cyclase inhibitors (OSCi) from a focused pharmacophore-based screen. Optimization of the most tractable hits gave a series of compounds showing inhibition of cholesterol biosynthesis at 2mg/kg in the rat with distinct pharmacokinetic profiles. Two compounds were selected for toxicological study in the rat for 21 days in order to test the hypothesis that low systemic exposure could be used as a strategy to avoid the ocular side effects previously described with OSCi. We demonstrate that for this series of inhibitors, a reduction of systemic exposure is not sufficient to circumvent cataract liabilities.

Development of a Series of Kynurenine 3-Monooxygenase Inhibitors Leading to a Clinical Candidate for the Treatment of Acute Pancreatitis

Recently, we reported a novel role for KMO in the pathogenesis of acute pancreatitis (AP). A number of inhibitors of kynurenine 3-monooxygenase (KMO) have previously been described as potential treatments for neurodegenerative conditions and particularly for Huntingtons disease. However, the inhibitors reported to date have insufficient aqueous solubility relative to their cellular potency to be compatible with the intravenous (iv) dosing route required in AP. We have identified and optimized a novel series of high affinity KMO inhibitors with favorable physicochemical properties. The leading example is exquisitely selective, has low clearance in two species, prevents lung and kidney damage in a rat model of acute pancreatitis, and is progressing into preclinical development.

The discovery of potent and selective kynurenine 3-monooxygenase inhibitors for the treatment of acute pancreatitis

A series of potent, competitive and highly selective kynurenine monooxygenase inhibitors have been discovered via a substrate-based approach for the treatment of acute pancreatitis. The lead compound demonstrated good cellular potency and clear pharmacodynamic activity in vivo.