Myeloid cell leukemia-1 (Mcl-1), a member of the Bcl-2 family of proteins, is overexpressed and amplified in various cancers and promotes the aberrant survival of tumor cells that otherwise would undergo apoptosis. Here we describe the discovery of potent and selective Mcl-1 inhibitors using fragment-based methods and structure-based design. NMR-based screening of a large fragment library identified two chemically distinct hit series that bind to different sites on Mcl-1. Members of the two fragment classes were merged together to produce lead compounds that bind to Mcl-1 with a dissociation constant of <100 nM with selectivity for Mcl-1 over Bcl-xL and Bcl-2. Structures of merged compounds when complexed to Mcl-1 were obtained by X-ray crystallography and provide detailed information about the molecular recognition of small-molecule ligands binding Mcl-1. The compounds represent starting points for the discovery of clinically useful Mcl-1 inhibitors for the treatment of a wide variety of cancers.

Drug discovery programs increasingly are focusing on allosteric modulators as a means to modify the activity of G protein-coupled receptor (GPCR) targets. Allosteric binding sites are topographically distinct from the endogenous ligand (orthosteric) binding site, which allows for co-occupation of a single receptor with the endogenous ligand and an allosteric modulator that can alter receptor pharmacological characteristics. Negative allosteric modulators (NAMs) inhibit and positive allosteric modulators (PAMs) enhance the affinity and/or efficacy of orthosteric agonists. Established approaches for estimation of affinity and efficacy values for orthosteric ligands are not appropriate for allosteric modulators, and this presents challenges for fully understanding the actions of novel modulators of GPCRs. Metabotropic glutamate receptor 5 (mGlu 5 ) is a family C GPCR for which a large array of allosteric modulators have been identified. We took advantage of the many tools for probing allosteric sites on mGlu 5 to validate an operational model of allosterism that allows quantitative estimation of modulator affinity and cooperativity values. Affinity estimates derived from functional assays fit well with affinities measured in radioligand binding experiments for both PAMs and NAMs with diverse chemical scaffolds and varying degrees of cooperativity. We observed modulation bias for PAMs when we compared mGlu 5 -mediated Ca 2ϩ mobilization and extracellular signalregulated kinase 1/2 phosphorylation data. Furthermore, we used this model to quantify the effects of mutations that reduce binding or potentiation by PAMs. This model can be applied to PAM and NAM potency curves in combination with maximal fold-shift data to derive reliable estimates of modulator affinities.

The renal outer medullary potassium channel (ROMK) is expressed in the kidney tubule and critically regulates sodium and potassium balance. The physiological functions of other inward rectifying K ϩ (Kir) channels expressed in the nephron, such as Kir7

Cellular and genetic evidence suggest that inhibition of ATAD2 could be a useful strategy to treat several types of cancer. To discover small-molecule inhibitors of the bromodomain of ATAD2, we used a fragment-based approach. Fragment hits were identified using NMR spectroscopy, and ATAD2 was crystallized with three of the hits identified in the fragment screen.

The renal outer medullary potassium (K ϩ ) channel, ROMK (Kir1.1), is a putative drug target for a novel class of loop diuretic that would lower blood volume and pressure without causing hypokalemia. However, the lack of selective ROMK inhibitors has hindered efforts to assess its therapeutic potential. In a high-throughput screen for small-molecule modulators of ROMK, we previously identified a potent and moderately selective ROMK antagonist, 7,13-bis(4-nitrobenzyl)-1,4,10-trioxa-7,13-diazacyclopentadecane (VU590), that also inhibits Kir7.1. Because ROMK and Kir7.1 are coexpressed in the nephron, VU590 is not a good probe of ROMK function in the kidney. Here we describe the development of the structurally related inhibitor 2,2Ј-oxybis(methylene)bis(5-nitro-1H-benzo-[d]imidazole) (VU591), which is as potent as VU590 but is selective for ROMK over Kir7.1 and more than 65 other potential off-targets. VU591 seems to block the intracellular pore of the channel. The development of VU591 may enable studies to explore the viability of ROMK as a diuretic target.

Inward rectifier potassium (Kir) channels have been postulated as therapeutic targets for several common disorders including hypertension, cardiac arrhythmias and pain. With few exceptions, however, the small-molecule pharmacology of this family is limited to nonselective cardiovascular and neurologic drugs with off-target activity toward inward rectifiers. Consequently, the actual therapeutic potential and 'drugability' of most Kir channels has not yet been determined experimentally. The purpose of this review is to provide a comprehensive summary of publicly disclosed Kir channel small-molecule modulators and highlight recent targeted drug-discovery efforts toward Kir1.1 and Kir2.1. The review concludes with a brief speculation on how the field of Kir channel pharmacology will develop over the coming years and a discussion of the increasingly important role academic laboratories will play in this progress.Members of the inward rectifier family of potassium (Kir) channels regulate a myriad of physiological processes, including cardiac function, pain processing and opioid action, learning and memory, insulin secretion and epithelial solute transport [1,2]. Some inward rectifiers occupy unique physiological niches that raise intriguing questions about their potential as therapeutic targets. Unfortunately, however, the small-molecule pharmacology of inward rectifiers has remained essentially undeveloped since the first member was cloned nearly 20 years ago [3]. This dearth of pharmacological tools has hindered efforts to develop even a cursory understanding of the physiology of some Kir channels and represents a critical barrier to defining their therapeutic potential. The main goals of this review article are:• To provide a comprehensive summary of disclosed small-molecule modulators of Kir channels, highlighting the few examples where pharmacology has illuminated a deeper understanding of their physiology and 'druggability'; © 2010 Future Science Ltd † Author for correspondence: Tel.: +1 615 343 7385, Fax: +1 615 343 3916, jerod.s.denton@vanderbilt.edu. Financial & competing interests disclosureThe authors are supported by NIH grants 1R21NS5704111 (Jerod S Denton) and 1U54MH084659-01 (Brian A Chauder), an American Heart Association-Southeast Affiliate Beginning Grant-In-Aid (Jerod S Denton), a National Kidney Foundation Postdoctoral Fellowhip grant (Gautam Bhave) and the Vanderbilt Department of Anesthesiology BH Robbins Scholars Program (Daniel Lonergan).The authors have no other relevant affliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.No writing assistance was utilized in the production of this manuscript. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript• To review recent adva...

Condensation of phenols with but-2-enal and 3-methylbut-2-enal in the presence of phenylboronic acid in acetic acid-toluene solution leads to substituted and condensed 2H-chromenes, constituting a mild and advantageous complement to classical routes for this class of heterocycles.

From ANNs to NAMs! Data from an experimental metabotropic glutamate receptor 5 (mGlu5) high‐throughput screen (HTS) were employed to train artificial neural networks (ANNs) based on 345 confirmed negative allosteric modulators (NAMs) and 155 774 inactive compounds. This effort identified two potent mGlu5 NAMs with a unique chemotype. Optimization afforded a tool compound (shown), active in mouse models of anxiety and addiction.