Eugene Lvovich Piatnitski Chekler

Transcriptional Profiling of a Selective CREB Binding Protein Bromodomain Inhibitor Highlights Therapeutic Opportunities.

Bromodomains are involved in transcriptional regulation through the recognition of acetyl lysine modifications on diverse proteins. Selective pharmacological modulators of bromodomains are lacking, although the largely hydrophobic nature of the pocket makes these modules attractive targets for small-molecule inhibitors. This work describes the structure-based design of a highly selective inhibitor of the CREB binding protein (CBP) bromodomain and its use in cell-based transcriptional profiling experiments. The inhibitor downregulated a number of inflammatory genes in macrophages that were not affected by a selective BET bromodomain inhibitor. In addition, the CBP bromodomain inhibitor modulated the mRNA level of the regulator of G-protein signaling 4 (RGS4) gene in neurons, suggesting a potential therapeutic opportunity for CBP inhibitors in the treatment of neurological disorders.

1-(2-Hydroxy-2-methyl-3-phenoxypropanoyl)indoline-4-carbonitrile Derivatives as Potent and Tissue Selective Androgen Receptor Modulators

We present a novel series of selective androgen receptor modulators (SARMs) which shows excellent biological activity and physical properties. 1-(2-Hydroxy-2-methyl-3-phenoxypropanoyl)-indoline-4-carbonitriles showed potent binding to the androgen receptor (AR) and activated AR-mediated transcription in vitro. Representative compounds demonstrated diminished activity in promoting the intramolecular interaction between the AR carboxyl (C) and amino (N) termini. This N/C-termini interaction is a biomarker assay for the undesired androgenic responses in vivo. In orchidectomized rats, daily administration of a lead compound from this series showed anabolic activity by increasing levator ani muscle weight. Importantly, minimal androgenic effects (increased tissue weights) were observed in the prostate and seminal vesicles, along with minimal repression of circulating luteinizing hormone (LH) levels and no change in the lipid and triglyceride levels. This lead compound completed a two week rat toxicology study, and was well tolerated at doses up to 100 mg/kg/day, the highest dose tested, for 14 consecutive days.

Direct photocapture of bromodomains using tropolone chemical probes

Medicinal chemistry techniques, including structure-based molecular design, fragment replacement and synthetic library enablement, were used to create potent inhibitors of bromodomain and extraterminal domain (BET) and CREB bindingprotein bromodomains. One inhibitor featured the homoaromatic tropolone methyl ether motif as a mimic of acetyl lysine, as confirmed by X-ray crystallography. The intrinsic photoreactivity of the tropone fragment was harnessed successfully to directly photolabel recombinant bromodomains which inspired further development of a clickable probe to assess BRD4 target engagement by (+)-JQ1 as a representative BET inhibitor in a complex proteome. The antimitoticnatural productcolchicine and related natural products that contain the tropolone ring system were also found to be bromodomain inhibitors, and surprisingly, our probe was shown to photolabel tubulin. These results highlight the caution that should be exercised when considering the selectivity of pharmacological agents, and photoreactive chemical probes should be assessed for their intrinsic ability to directly label their biological targets with a view to creating useful chemoproteomic tools.

Structure-Based Design of Highly Selective Inhibitors of the CREB Binding Protein Bromodomain

Chemical probes are required for preclinical target validation to interrogate novel biological targets and pathways. Selective inhibitors of the CREB binding protein (CREBBP)/EP300 bromodomains are required to facilitate the elucidation of biology associated with these important epigenetic targets. Medicinal chemistry optimization that paid particular attention to physiochemical properties delivered chemical probes with desirable potency, selectivity, and permeability attributes. An important feature of the optimization process was the successful application of rational structure-based drug design to address bromodomain selectivity issues (particularly against the structurally related BRD4 protein).

Probing androgen receptor co-factor selectivity profiles: a chemical tool to determine cross-talk between androgen receptor and β-catenin in vivo

Previous reports on Selective Androgen Receptor Modulators (SARMs) have described their activity primarily by their tissue selectivity in animal models. A few SARMs have been described with tissue selectivity ascribed to their diminished activity in promoting the intramolecular interaction between the androgen receptor (AR) carboxyl and amino termini. In the current study we characterized an AR ligand PF-05314882 that has an unusual in vitro selectivity profile in AR cell based assays. This SARM was previously reported to have tissue selective AR activity in rats. In the current study PF-05314882 bound to the AR ligand binding domain with good affinity and activated AR-mediated transcription in vitro. However, unlike naturally occurring androgens and other SARMs, PF-05314882 does not stimulate interaction between AR and β-catenin. Consistent with this observation, PF-05314882 had only weak activity on androgen-AR dependent inhibition of Wnt reporter activity. In castrated rats, the daily administration of PF-05314882 had anabolic activity on increasing levator ani muscle weight and elevating RNA expression of androgen regulated metabolic genes in the liver. Similar to previously described tissue selective SARMs, PF-05314882 has very little activity in the prostate, seminal vesicles and in repressing circulating luteinizing hormone (LH) levels. More importantly, since AR and β-catenin have been shown to play important roles in overlapping tissues including adipose, bone, hair and in diseases such as prostate cancer, PF-05314882 may be an important pharmacologic tool to elucidate the role and extent of cross-talk between AR and β-catenin.

Structure-Based Approach To Identify 5-[4-Hydroxyphenyl]pyrrole-2-carbonitrile Derivatives as Potent and Tissue Selective Androgen Receptor Modulators

In an effort to find new and safer treatments for osteoporosis and frailty, we describe a novel series of selective androgen receptor modulators (SARMs). Using a structure-based approach, we identified compound 7, a potent AR (ARE EC50 = 0.34 nM) and selective (N/C interaction EC50 = 1206 nM) modulator. In vivo data, an AR LBD X-ray structure of 7, and further insights from modeling studies of ligand receptor interactions are also presented.