Hit Series Research Articles

The Wire Goes to College

For five seasons, HBO's hit series The Wire delivered sharp social commentary on topics from poverty to failed institutions in urban America. Now, professors in a range of fields are enlivening their classrooms by using the show as a platform from which to launch discussions on social problems, urban policy, and social science.

Imidazolopiperazines: Hit to Lead Optimization of New Antimalarial Agents

Starting from a hit series from a GNF compound library collection and based on a cell-based proliferation assay of Plasmodium falciparum, a novel imidazolopiperazine scaffold was optimized. SAR for this series of compounds is discussed, focusing on optimization of cellular potency against wild-type and drug resistant parasites and improvement of physiochemical and pharmacokinetic properties. The lead compounds in this series showed good potencies in vitro and decent oral exposure levels in vivo. In a Plasmodium berghei mouse infection model, one lead compound lowered the parasitemia level by 99.4% after administration of 100 mg/kg single oral dose and prolonged mice survival by an average of 17.0 days. The lead compounds were also well-tolerated in the preliminary in vitro toxicity studies and represents an interesting lead for drug development.

Gender Norms in the Twilight Series

The hit series Twilight replicates gender stereotypes that sociologists have been debunking for decades. Rebecca Hayes-Smith highlights the gravity of making light of harmful gender messages.

Selective antagonists of mouse trace amine-associated receptor 1 (mTAAR1): Discovery of EPPTB (RO5212773)

High throughput screening of the Roche compound library identified benzanilides such as 1 and 2 as antagonists of TAAR1. Optimisation of this hit series led to the first selective TAAR1 antagonist (N-(3-Ethoxy-phenyl)-4-pyrrolidin-1-yl-3-trifluoromethyl-benzamide EPPTB (RO5212773, 9f) having IC(50) of 28 nM at mouse TAAR1.

Using Electrophysiology and In Silico Three-Dimensional Modeling to Reduce Human Ether-à-go-go Related Gene K+ Channel Inhibition in a Histamine H3 Receptor Antagonist Program

The histamine H3 receptor (H3R) plays a regulatory role in the presynaptic release of histamine and several other neurotransmitters, and thus, it is an attractive target for central nervous system indications including cognitive disorders, narcolepsy, attention-deficit hyperactivity disorder, and pain. The development of H3R antagonists was complicated by the similarities between the pharmacophores of H3R and human Ether-à-go-go related gene (hERG) channel blockers, a fact that probably prevented promising compounds from being progressed into the clinic. Using a three-dimensional in silico modeling approach complemented with automated and manual patch clamping, we were able to separate these two pharmacophores and to develop highly potent H3R antagonists with reduced risk of hERG liabilities from initial hit series with low selectivity identified in a high-throughput screening campaign.

Discovery of a 1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione series of inhibitors of HIV-1 capsid assembly

The discovery of a 1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione series of inhibitors of HIV-1 capsid assembly is described. Synthesis of analogs of the 1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione hit established structure–activity relationships. Replacement of the enamine functionality of the hit series with either an imidazole or a pyrazole ring led to compounds that inhibited both capsid assembly and reverse transcriptase. Optimization of the bicyclic benzodiazepine scaffold to include a 3-phenyl substituent led to lead compound 48, a pure capsid assembly inhibitor with improved antiviral activity.

Abstract 5778: Fragment-based drug discovery of selective inhibitors of fibroblast growth factor receptor (FGFr)

Abstract Recent data in a number of tumour types has implicated Fibroblast Growth Factor (FGF) and Fibroblast Growth Factor receptor (FGFr) signalling as being key to the molecular pathology of cancer. This poster will describe fragment based drug discovery using biophysical screening to identify initial fragments. Subsequently, in the fragments-to-leads stage a detailed structural understanding of the binding interactions between the fragment and its target protein utilised X-ray crystallography and NMR. Starting with different fragments allows several lead series to be identified, often by synthesizing only small numbers of compounds. A fragment screening campaign was conducted against the FGFr-1 to detect very low molecular weight compounds that bound to the hinge region of the kinase. The screening produced several fragment molecules (Molecular Weight <250 Da) which were in the micromolar range and confirmed binding mode in X-ray crystallography. One X-ray hit series that was 120 uM verse FGFr-3 will be described. Several iterations of structure-guided medicinal chemistry led to the identification of a lead compound with 3 nM affinity for FGFr-3, good cell activity and 30-fold selectivity verse VEGFr-2 with good oral activity. The lead was optimised to afford a compound that showed good PK/PD and efficacy. This poster represents first disclosure of the structure of the lead series and illustrates how a fragment-based drug discovery approach can be efficiently used to discover compounds advanced nanomolar compounds with oral bioavailability. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5778.

Turkish soap operas in the Arab world: social liberation or cultural alienation?

In 1980 oil magnate J.R. Ewing was shot and injured in the hit series Dallas, which featured an unconventional family’s struggles over power, wealth and sex. The shot was heard around the world, with millions of fans desperately wondering “Who shot J.R.?”. It was the first time that a TV series had captivated simultaneously so many people around the world. Five years later, the Arabs were shooting at the stars with the launch of the first Arab satellite system, Arabsat-1. Except for experts and visionaries, no one was predicting that it was “the beginning of the end” for the state domination of television in the Arab world. Almost a quarter of a century later, on August 30, 2008, 85 million Arab viewers were glued to their TV sets for the finale of the Syrian-dubbed Turkish soap opera, Gümüş1 (Noor2 in Arabic), a Kanal D production that received little attention in its homeland in 2005. After falling in the past for Victoria Principal, Ridge Forrester, and Latin American telenovela characters Kassandra and Rosalinda , Arab audiences are now turning to Turkey, a close yet estranged neighbor with whom they share a tumultuous history. The mastermind behind this phenomenon has been the MBC (Middle East Broadcasting Center) media empire, a combination of Saudi capital and Middle Eastern know-how, and a success story that started in the 1990s with the birth of a private Arab media field. As Naomi Sakr explains, many factors fuel the field’s potential including the fact that “Media flows are (…) facilitated where the language is shared3”. The Arab market is indeed unique: a large and essentially young audience with some 20 countries sharing a common language. Researchers have thus observed a relative “depoliticization” of media over the years with the progressive development of mass entertainment programming.

“This Famous Duke of Milan of Whom So Often I Have Heard Renown”: William Hutt at the Stratford and New Burbage Festivals

William Hutt left an indelible mark on Canadian theatre, representing for audience members and critics the epitome of a distinctly Canadian style of classical acting. It is this reputation, writes ROBERT ORMSBY, that the writers of the hit series, Slings and Arrows, played with to great effect when they cast Hutt as a King Lear-like character in the show's final season.

Discovery and optimization of RO-85, a novel drug-like, potent, and selective P2X 3 receptor antagonist

Despite the extensive literature describing the role of the ATP-gated P2X 3 receptors in a variety of physiological processes the potential of antagonists as therapeutic agents has been limited by the lack of drug-like selective molecules. In this paper we report the discovery and optimization of RO-85, a novel drug-like, potent and selective P2X 3 antagonist. High-throughput screening of the Roche compound collection identified a small hit series of heterocyclic amides from a large parallel synthesis library. Rapid optimization, facilitated by high-throughput synthesis, focusing on increasing potency and improving drug-likeness resulted in the discovery of RO-85.

Abstract A1: The physiological form of MetAP2 can be inhibited through binding to either of the two active-site metals

Abstract Methionine aminopeptidases (MetAP) are metalloenzymes that remove the N-terminal initiator methionine from newly synthesized polypeptides allowing essential post-translational modifications such as acetylation and myristoylation to take place. MetAP2, one of the two eukaryotic forms of the enzyme, was identified as the target of fumagillin, a natural product with anti-angiogenic properties that inhibits the proliferation of endothelial cells. Clinical activity has been seen for a semi-synthetic analogue of fumagillin, TNP470, suggesting MetAP2 is a good target for inhibiting angiogenesis. In vitro, MetAP2 appears to have sites for two divalent metal ions within its active site but there has been much discussion around the identity and number of metal ions actually present in the physiological states of the various MetAPs. An understanding of the physiologically relevant metalloform of the enzyme is essential for designing inhibitors that are active in cells. We have used tool compounds that bind the active site metals in diverse ways to investigate the relevance of the two potential metal binding sites in MetAP2. Using our fragment-based screening approach, Pyramid™, we screened the manganese-form of the MetAP2 enzyme. We identified multiple low-molecular weight fragment hits and confirmed their modes of binding to the two metals in the active site of MetAP2 by X-ray crystallography. Three hit series, which bound metal 1 only, metal 2 only or both metals 1 and 2 were chosen for further optimization using structure-based drug design. Optimized lead compounds had potent inhibitory activity against the in vitro MetAP2 enzyme (∼100 nM) and in HUVEC proliferation assays, whilst also showing greater than 1000-fold selectivity for MetAP2 over MetAP1. Examples from each series, representing different active site metal binding modes, were used as tool compounds to investigate the mechanism of action in cells. The levels of the MetAP2 substrate, 14-3-3, were monitored by western blot in HUVECs treated with these compounds. Levels of methionylated 14-3-3 increased upon treatment with compounds from each of our series indicating the substrate was not being processed and that in each case the compound was inhibiting MetAP2 in these cells. These data indicate that the physiological form of MetAP2 can be inhibited by compounds which bind solely to either of the two active-site metals, suggesting that both metals must be present in the intra-cellular form of MetAP2 and allowing multiple approaches to inhibiting this key angiogenic target. The lead series identified here provide chemically diverse scaffolds for further optimization of drug like properties. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A1.

The identification of structurally novel, selective, orally bioavailable positive modulators of mGluR2

The optimisation of an HTS hit series ( 1) leading to the identification of structurally novel, selective, orally bioavailable mGluR2 positive modulators GSK1331258 and GSK1331268 is described. Structure–activity relationships, attenuation of dopaminergic activity, and potentiation of mGluR2 responses in rat hippocampal MPP-DG synapses are also reported.

Discovery of dipiperidines as new antitubercular agents.

As part of our ongoing research effort to develop new therapeutics for treatment of tuberculosis (TB), we synthesized a combinatorial library of 10,358 compounds on solid support using a pool-and-split technique and tested the resulting compounds for activity against Mycobacteriumtuberculosis. Structure-activity relationship (SAR) evaluation identified new compounds with antitubercular activity, including a novel hit series that is structurally unrelated to any existing antitubercular drugs, dipiperidines. Dipiperidine representatives exhibited MIC values as low as 7.8microM, the ability to induce promoter Rv0341 activated in response to cell wall biosynthesis inhibition, relatively low nonspecific cellular toxicity in the range of 30-162microM, and logP values less than 4.

Enhanced HTS Hit Selection via a Local Hit Rate Analysis

The postprocessing of high-throughput screening (HTS) results is complicated by the occurrence of false positives (inactive compounds misidentified as active by the primary screen) and false negatives (active compounds misidentified as inactive by the primary screen). An activity cutoff is frequently used to select "active" compounds from HTS data; however, this approach is insensitive to both false positives and false negatives. An alternative method that can minimize the occurrence of these artifacts will increase the efficiency of hit selection and therefore lead discovery. In this work, rather than merely using the activity of a given compound, we look at the presence and absence of activity among all compounds in its "chemical space neighborhood" to give a degree of confidence in its activity. We demonstrate that this local hit rate (LHR) analysis method outperforms hit selection based on ranking by primary screen activity values across ten diverse high throughput screens, spanning both cell-based and biochemical assay formats of varying biology and robustness. On average, the local hit rate analysis method was approximately 2.3-fold and approximately 1.3-fold more effective in identifying active compounds and active chemical series, respectively, than selection based on primary activity alone. Moreover, when applied to finding false negatives, this method was 2.3-fold better than ranking by primary activity alone. In most cases, novel hit series were identified that would have otherwise been missed. Additional uses of and observations regarding this HTS analysis approach are also discussed.

Design and synthesis of substituted nicotinamides as inhibitors of soluble epoxide hydrolase

A series of potent nicotinamide inhibitors of soluble epoxides hydrolase (sEH) is disclosed. This series was designed using structure-based deconstruction and a combination of two HTS hit series, resulting in hybrid analogs that retained the optimal potency from one series, and acceptable in vitro metabolic stability from the other. Structure-guided optimization of these analogs gave rise to nanomolar inhibitors of human sEH that had acceptable plasma exposure to qualify them as probes to determine the in vivo phenotypic consequences of sEH inhibition.

Identification and optimisation of novel and selective small molecular weight kinase inhibitors of mTOR

A pharmacophore mapping approach, derived from previous experience of PIKK family enzymes, was used to identify a hit series of selective inhibitors of the mammalian target of rapamycin (mTOR). Subsequent refinement of the SAR around this hit series based on a tri-substituted triazine scaffold has led to the discovery of potent and selective inhibitors of mTOR.

Exploring 9-benzyl purines as inhibitors of glutamate racemase (MurI) in Gram-positive bacteria

An early SAR study of a screening hit series has generated a series of 9-benzyl purines as inhibitors of bacterial glutamate racemase (MurI) with micromolar enzyme potency and improved physical properties. X-ray co-crystal EI structures were obtained.

Phenylglycine and phenylalanine derivatives as potent and selective HDAC1 inhibitors (SHI-1)

An HTS screening campaign identified a series of low molecular weight phenols that showed excellent selectivity (>100-fold) for HDAC1/HDAC2 over other Class I and Class II HDACs. Evolution and optimization of this HTS hit series provided HDAC1-selective (SHI-1) compounds with excellent anti-proliferative activity and improved physical properties. Dose-dependent efficacy in a mouse HCT116 xenograft model was demonstrated with a phenylglycine SHI-1 analog.

From Astemizole to a Novel Hit Series of Small-Molecule Somatostatin 5 Receptor Antagonists via GPCR Affinity Profiling

The H1R antagonist astemizole was identified as a somatostatin 5 (SST5) receptor antagonist by a comparative sequence analysis of the consensus drug binding pocket of GPCRs. Subsequently, a similarity analysis of GPCR affinity profiles of astemizole versus a set of in-house GPCR-biased combinatorial libraries revealed new chemical entry points that led to a second lead series with nanomolar binding affinity.

‘Tough Love’ To Arrogant, Underperforming Foundations

‘Tough Love’ To Arrogant, Underperforming Foundations