Small-molecule targeting AMPA-mediated excitotoxicity has therapeutic effects in mouse models for multiple sclerosis.

While most research and treatments for multiple sclerosis (MS) focus on autoimmune reactions causing demyelination, it is possible that neurodegeneration precedes the autoimmune response. Hence, glutamate receptor antagonists preventing excitotoxicity showed promise in MS animal models, though blocking glutamate signaling prevents critical neuronal functions. This study reports the discovery of a small molecule that prevents AMPA-mediated excitotoxicity by targeting an allosteric binding site. A machine learning approach was used to screen for small molecules targeting the AMPA receptor GluA2 subunit. The lead candidate has potent effects in restoring neurological function and myelination while reducing the immune response in experimental autoimmune encephalitis and cuprizone MS mouse models without affecting basal neurotransmission or learning and memory. These findings facilitate development of a treatment for MS with a different mechanism of action than current immune modulatory drugs and avoids important off-target effects of glutamate receptor antagonists. This class of MS therapeutics could be useful as an alternative or complementary treatment to existing therapies.

The Trifluoromethyl Group as a Bioisosteric Replacement of the Aliphatic Nitro Group in CB1 Receptor Positive Allosteric Modulators.

The first generation of CB1 positive allosteric modulators (e.g., ZCZ011) featured a 3-nitroalkyl-2-phenyl-indole structure. Although a small number of drugs include the nitro group, it is generally not regarded as being "drug-like", and this is particularly true for aliphatic nitro groups. There are very few case studies where an appropriate bioisostere replaced a nitro group that had a direct role in binding. This may be indicative of the difficulty of replicating its binding interactions. Herein, we report the design and synthesis of ligands targeting the allosteric binding site on the CB1 cannabinoid receptor, in which a CF3 group successfully replaced the aliphatic NO2. In general, the CF3-bearing compounds were more potent than their NO2 equivalents and also showed improved in vitro metabolic stability. The CF3 analogue (1) with the best balance of properties was selected for further pharmacological evaluation. Pilot in vivo studies showed that (±)-1 has similar activity to (±)-ZCZ011, with both showing promising efficacy in a mouse model of neuropathic pain.

CDP-choline accumulation in breast and colorectal cancer cells treated with a GSK-3-targeting inhibitor.

PURPOSE: Glycogen synthase kinase 3 (GSK3) is a key controlling element of many cellular processes including cell-cycle progression and recent studies suggest that GSK3 is a potential anticancer target. Changes in glucose metabolism associated with GSK3 inhibition may impact on lipid synthesis, whilst lipid metabolites can act as molecular response markers. METHODS: Here, SKBr3 breast and HCT8 colorectal cancer cells were treated with the GSK3 inhibitor SB216763, and [14C (U)] glucose and [3H] choline incorporation into lipids was determined. Cell extracts from treated cells were subject to 31P NMR spectroscopy. RESULTS: SB216763 treatment decreased choline incorporation into lipids and caused an accumulation of CDP-choline which was accompanied by decreased conversion of glucose into lipid components. CONCLUSION: SB216763 profoundly inhibits phospholipid synthesis in cancer cells which demonstrate accumulation of CDP-choline detectable by 31P NMR spectroscopy. Metabolic changes in lipid metabolism present potential response markers to drugs targeting GSK3.

Small Molecule Inhibitors of Metabolic Enzymes Repurposed as a New Class of Anthelmintics.

The enormous prevalence of infections caused by parasitic nematodes worldwide, coupled to the rapid emergence of their resistance to commonly used anthelmintic drugs, presents an urgent need for the discovery of new drugs. Herein, we have identified several classes of small molecules with broad spectrum activity against these pathogens. Previously, we reported the identification of carnitine palmitoyltransferases (CPTs) as a representative class of enzymes as potential targets for metabolic chokepoint intervention that was elucidated from a combination of chemogenomic screening and experimental testing in nematodes. Expanding on these previous findings, we have discovered that several chemical classes of known small molecule inhibitors of mammalian CPTs have potent activity as anthelmintics. Cross-clade efficacy against a broad spectrum of adult parasitic nematodes was demonstrated for multiple compounds from different series. Several analogs of these initial hit compounds were designed and synthesized. The compounds we report represent a good starting point for further lead identification and optimization for development of new anthelmintic drugs with broad spectrum activity and a novel mechanism of action.

Response Detection of Castrate-Resistant Prostate Cancer to Clinically Utilised and Novel Treatments by Monitoring Phospholipid Metabolism.

Androgen receptor (AR) activation is the primary driving factor in prostate cancer which is initially responsive to castration but then becomes resistant (castration-resistant prostate cancer (CRPC)). CRPC cells still retain the functioning AR which can be targeted by other therapies. A recent promising development is the use of inhibitors (Epi-1) of protein-protein interaction to inhibit AR-activated signalling. Translating novel therapies into the clinic requires sensitive early response indicators. Here potential response markers are explored. Growth inhibition of prostate cancer cells with flutamide, paclitaxel, and Epi-1 was measured using the MTT assay. To simulate choline-PET scans, pulse-chase experiments were carried out with [3H-methyl]choline and proportion of phosphorylated activity was determined after treatment with growth inhibitory concentrations of each drug. Extracts from treated cells were also subject to 31P-NMR spectroscopy. Cells treated with flutamide demonstrated decreased [3H-methyl]choline phosphorylation, whilst the proportion of phosphorylated [3H-methyl]choline that was present in the lipid fraction was increased in Epi-1-treated cells. Phospholipid breakdown products, glycerophosphorylcholine and glycerophosphoethanolamine levels, were shown by 31P-NMR spectroscopy to be decreased to undetectable levels in cells treated with Epi-1. LNCaP cells responding to treatment with novel protein-protein interaction inhibitors suggest that 31P-NMR spectroscopy may be useful in detecting response to this promising therapy.

Development of Fluorinated Analogues of Perhexiline with Improved Pharmacokinetic Properties and Retained Efficacy.

We designed and synthesized perhexiline analogues that have the same therapeutic profile as the parent cardiovascular drug but lacking its metabolic liability associated with CYP2D6 metabolism. Cycloalkyl perhexiline analogues 6a-j were found to be unsuitable for further development, as they retained a pharmacokinetic profile very similar to that shown by the parent compound. Multistep synthesis of perhexiline analogues incorporating fluorine atoms onto the cyclohexyl ring(s) provided a range of different fluoroperhexiline analogues. Of these, analogues 50 (4,4-gem-difluoro) and 62 (4,4,4',4'-tetrafluoro) were highly stable and showed greatly reduced susceptibility to CYP2D6-mediated metabolism. In vitro efficacy studies demonstrated that a number of derivatives retained acceptable potency against CPT-1. Having the best balance of properties, 50 was selected for further evaluation. Like perhexiline, it was shown to be selectively concentrated in the myocardium and, using the Langendorff model, to be effective in improving both cardiac contractility and relaxation when challenged with high fat buffer.

Probing the PI3K/Akt/mTor pathway using 31P-NMR spectroscopy: routes to glycogen synthase kinase 3.

Akt is an intracellular signalling pathway that serves as an essential link between cell surface receptors and cellular processes including proliferation, development and survival. The pathway has many downstream targets including glycogen synthase kinase3 which is a major regulatory kinase for cell cycle transit as well as controlling glycogen synthase activity. The Akt pathway is frequently up-regulated in cancer due to overexpression of receptors such as the epidermal growth factor receptor, or mutation of signalling pathway kinases resulting in inappropriate survival and proliferation. Consequently anticancer drugs have been developed that target this pathway. MDA-MB-468 breast and HCT8 colorectal cancer cells were treated with inhibitors including LY294002, MK2206, rapamycin, AZD8055 targeting key kinases in/associated with Akt pathway and the consistency of changes in 31P-NMR-detecatable metabolite content of tumour cells was examined. Treatment with the Akt inhibitor MK2206 reduced phosphocholine levels in MDA-MB-468 cells. Treatment with either the phosphoinositide-3-kinase inhibitor, LY294002 and pan-mTOR inhibitor, AZD8055 but not pan-Akt inhibitor MK2206 increased uridine-5'-diphosphate-hexose cell content which was suppressed by co-treatment with glycogen synthase kinase 3 inhibitor SB216763. This suggests that there is an Akt-independent link between phosphoinositol-3-kinase and glycogen synthase kinase3 and demonstrates the potential of 31P-NMR to probe intracellular signalling pathways.

Multicomponent solvent-free synthesis of benzimidazolyl imidazo[1,2-a]-pyridine under microwave irradiation.

A novel one-pot, three-component reaction employing variously substituted benzimidazole-linked amino pyridines, aldehydes, and isonitriles catalyzed by scandium(III) triflate under solvent-free conditions were accomplished. This new synthetic methodology facilitates the rapid generation of intricate molecular frameworks in three-dimensional fashion leading to benzimidazole-imidazo[1,2-a] pyridines. This approach is envisioned as an environmentally benign process and a simple operation to the biological interesting compounds. The present synthetic sequence permits the introduction of three points of structural diversity to expand chemical space with high purity and excellent yields.

Light fluorous-tagged traceless one-pot synthesis of benzimidazoles facilitated by microwave irradiation.

A novel protocol for rapid assemble of benzimidazole framework has been demonstrated. This method incorporated with light fluorous-tag provides a convenient method for diversification of benzimidazoles and for easy purification via fluorous solid-phase extraction (F-SPE) in a parallel manner. The key transformation of this study involves in situ reduction of aromatic nitro compound, amide formation, cyclization and aromatization promoted by microwave irradiation in a one-pot fashion. The strategy is envisaged to be applied for the establishment of drug-like small molecule libraries for high throughput screening.

Microwave-assisted linear approach toward highly substituted benzo[d]oxazol-5-yl-1H-benzo[d]imidazole on ionic liquid support.

A novel and efficient diversity-oriented synthetic approach was employed to access the benzo[d]oxazol-5-yl-1H-benzo[d]imidazole on ionic liquid support, which helps to absorb microwave irradiation. In this paper, we successfully coupled 4-hydroxy-3-nitrobenzoic acid onto ionic liquid-immobilized o-phenylenediamine, which subsequently underwent an acid mediated, ring closure reaction leading to benzimidazole derivatives. After hydrogenation of the nitro group to an amine, the resulting ionic liquid conjugate was reacted with 1,1-thiocarbonyldiimidazols to yield an ionic liquid tagged-benzoxazol. Final skeletal diversity of the present scaffold was further achieved by S-alkylation with alkyl and aryl bromides. The benzo[d]oxazol-5-yl-1H-benzo[d]imidazole was finally cleaved smoothly from the ionic liquid support with sodium methoxide in methanol under microwave irradiation. This methodology has provided access to a small, diverse library by straightforward and simple operations and could be applied readily in various drug discovery programs.

Chemical synthesis of the englerins.

In the long lasting battle against cancer, Nature sometimes gives a helping hand to researchers to find new drugs for the treatment of diseases and improvement of patients' well-being. Englerin A has emerged as a promising anticancer candidate as well as being an exciting synthetic challenge for organic chemists. This focus review summarizes the total syntheses reported to date and the synthetic approaches toward analogues of this fascinating natural product.

A modular synthesis of salvileucalin B structural domains.

A modular strategy leading to the salvileucalin B core structure has been accomplished. The developed synthetic strategy featured a bioinspired intramolecular Diels-Alder reaction to construct domain "A", REDOX chemistry to functionalize domain "B", and a palladium-mediated cross-coupling to install domain "C". This flexible approach should facilitate further chemical and biological investigations of this fascinating class of compounds.

Promoting regeneration of peripheral nerves in-vivo using new PCL-NGF/Tirofiban nerve conduits.

Poly(ε-caprolactone) (PCL) scaffolds were modified by grafting nerve growth factor (NGF) and Tirofiban (TF), a clinical anti-thrombosis drug, as a new biomaterial for producing nerve conduits to promote the regeneration of sciatic nerves. The successful grafting of NGF and TF onto PCL scaffolds was confirmed by FTIR and ESCA spectra. In-vitro growths of the PC12 cells in PCL-NGF and PCL-NGF/TF scaffolds, determined by MTS, were significantly higher (P < 0.05, n = 4) than those in the PCL scaffolds following three days of cultivation. Interestingly, this study evaluation of the PCL, PCL-NGF, and PCL-NGF/TF nerve conduits in a 12 mm long gap of the rat sciatic nerve defect model that the gastrocnemius muscle mass of the tested rats in the PCL-NGF/TF groups significantly exceeded those in the PCL-NGF and PCL group. In the rats that had been implanted with PCL-NGF/TF conduits, the generated nerves passed through those conduits, expressing beta-III tubulin (TB), growth association protein-43 (GAP-43) and myelin basic protein (MBP) along their longitudinal axis, and the proximal and distal nerve ends of the rats were successfully connected. Those that had been implanted with PCL and PCL-NGF conduits did not exhibit these effects, as revealed by an immunochemical study of the expressions of the proteins in the conduits. Moreover, counting within the dorsal horn of the spinal cord (C(5)) demonstrated that the numbers of CTB-HRP-labeled neurons in the rats that had been implanted with PCL-NGF/TF conduits were significantly higher than those in the other groups. In this study, in-vivo examinations of the use of newly designed PCL-NGF/TF conduits to promote the generation of nerves in a defective rat model significantly increased the gastrocnemius muscle mass, and led to the successful regeneration of nerves that bridged a 12 mm long defected gap of nerves in rats. However, more rats must be tested to confirm the efficacy the newly designed nerve conduits.

A method for parallel solid-phase synthesis of iodinated analogs of the cannabinoid receptor type I (CB1) inverse agonist rimonabant.

Rimonabant (acomplia) is a 1,5-diarylpyrazole derivative that acts as a type 1 cannabinoid receptor (CB1) inverse agonist. Here, we overview the role of this type of molecule in regulation of these receptors and their potential as starting points for the development of molecular probes to image the central nervous system (CNS). We then describe a novel protocol for the solid-phase parallel chemical synthesis of iodinated rimonabant analogs using germanium-functionalized, cross-linked polystyrene as the solid-support (or "resin"). The method allows for rapid derivatization at the key C-3 position of rimonabant from a common resin-bound precursor. The desired iodinated analogs are then obtained by ipso-iododegermylative cleavage from the resin using sodium iodide/N-chlorosuccinimide (NCS) in a fashion that ought to be readily adapted to the rapid preparation of isotopically labeled iodine derivatives for molecular imaging of CNS activity by positron emission tomography (PET, using ¹²4I) and single photon emission computerized tomography (SPECT, using (¹²³I) techniques. Toward this goal, we also show that the NCS-derived succinimide by-product that is released from the resin concomitantly with the potential imaging probe molecules can be readily and selectively removed by treatment of the crude soluble product mixture with a solid-supported hydrazide scavenger resin.

Chemistry of the cortistatins--a novel class of anti-angiogenic agents.

Synthetic efforts culminating the construction of several highly advanced intermediates, and completed syntheses of the recently disclosed cortistatin family of anti-proliferative agents are described in this perspective.

A method for parallel solid-phase synthesis of iodinated analogues of the CB1 receptor inverse agonist rimonabant.

A method for the parallel solid-phase synthesis (SPS) of iodinated analogues of Sanofi-Aventis' type 1 cannabinoid (CB1) receptor inverse agonist rimonabant (acomplia) has been developed. The method allows the synthesis of a range of C3 amide/hydrazide derivatives from a resin-bound C3 ester precursor. The C-Ge linkage to the Hypogel-200 resin is stable to the diversification conditions but allows ipso-iododegermylative cleavage using NaI/NCS even for the products containing the oxidatively labile hydrazide moiety.

A strategy for isotope containment during radiosynthesis--devolatilisation of bromobenzene by fluorous-tagging-Ir-catalysed borylation en route to the 4-phenylpiperidine pharmacophore.

Syntheses of two 4-phenylpiperidines from bromobenzene have been developed involving anchoring to a fluorous-tag, Ir-catalysed borylation, Pd- and Co-catalysed elaboration then traceless cleavage. Although performed using 'cold' (i.e. unlabelled) bromobenzene as the starting material, these routes have been designed to minimise material loss via volatile intermediates and expedite purification during radiosynthesis from 'hot' (i.e. [(14)C] labelled) bromobenzene.

Light-fluorous safety-catch arylgermanes - exceptionally robust, photochemically activated precursors for biaryl synthesis by Pd(0) catalysed cross-coupling.

A new class of arylgermane derivative that participate efficiently in Pd(0)-catalysed cross-coupling reactions with aryl bromides following photochemical activation is described.