NB-598: a potent competitive inhibitor of squalene epoxidase

NB-598, (E)N-ethyl-N-(6,6-dimethyl-2-hepten-4-ynyl)-3-[(3,3'-bith iophen-5-yl)methoxy]benzene-methanamine, was found to inhibit human microsomal squalene epoxidase (from Hep G2 cells) in a competitive manner. NB-598 inhibited cholesterol synthesis from [14C]acetate dose dependently in Hep G2 cells and increased the intracellular radioactivity of squalene. A single oral administration of NB-598 inhibited cholesterol synthesis from [14C]acetate in rats. Moreover, multiple oral administration of NB-598 to dogs decreased serum total and low density lipoprotein cholesterol levels and increased serum squalene levels. After termination of treatment, the reduced serum cholesterol and increased squalene levels returned to their control values.     

Identification of MK-1925: A selective,orally active and brain-penetrable opioid receptor-like 1 (ORL1) antagonist

Structure–activity relationship studies directed toward improving the metabolic stability of compound 1 resulted in the identification of 3-[5-(3,5-difluorophenyl)-3-({[(1S,3R)-3-fluorocyclopentyl]amino}methyl)-4-methyl-1H-pyrazol-1-yl]propanenitrile 39 (MK-1925) as a selective, orally available and brain-penetrable opioid receptor-like 1 (ORL1) antagonist. The compound also showed in vivo efficacy after oral dosing. Therefore, compound 39 was selected to undergo further studies as a clinical candidate.     

A study of the biologically active conformation of the cholecystokinin-4 dipeptide analogue GB-115

The biologically active conformation of N-(6-phenylhexanoyl)glycyl-tryptophan amide (GB-115), a highly active cholecystokinin-4 retro dipeptide analogue with the anxiolytic activity, has been studied using the conformational analysis by ¹H NMR spectroscopy in solution and the method of sterically restricted analogues. A study of the relationship between the preferable conformation in solution and the anxiolytic activity in the series of GB-115 derivatives showed that the biologically active conformation of this compound is the β-turn. Based on the data on the nuclear Overhauser effect ¹H NMR spectroscopy, this structure was identified as the β-turn of type II. Subsequent synthesis and study of the pharmacological activity of novel sterically restricted analogues of dipeptide GB-115: (2S)-2-{(3R)-3-[(6-phenylhexanoyl)amino]-2-oxopyrrolidine-1-yl}-3-(1H-indole-3-yl)propionic acid ethyl ester, N-(6-phenylhexanoyl)glycyl-N ^α-methyltryptophan ethyl ester, (2S)-2-[(10,11-dihydro-5H-dibenzo[b, f]azepin-5-ylcarbonyl)amino]-3-(1H-indole-3-yl)propionic acid methyl ester, and (2S)-2-[({3-[(ethoxycarbonyl)amino]-10,11-dihydro-5H-dibenzo[b, f]azepin-5-yl}carbonyl)amino]-3-(1H-indole-3-yl)propionic acid methyl ester confirmed that the β-turn of type II is the active conformation of GB-115.     

The Synthesis and Selective Cytotoxicity of New Mannich Bases,Derivatives of 19- and 28-Alkynyltriterpenoids

New propargylamines were synthesized in 72–75% yields by the interaction of 19-alkynylbetulin and 28-O-propargyl glycinamide of oleanolic acid with N-methylpiperazine under the Mannich reaction conditions. 19-[1-Methyl-4-prop-2-yn-1-yl-piperazine]-20,29,30-trinorbetulin was shown to manifest anticancer activity against one line of leukemia cells and two lines of colon cancer cells, whereas the growth of leukemia cells SR in the presence of 4-(4-methylpiperazin-1-yl)but-2-yn-1-yl-N-(3-hydroxy-28-oxoolean-12-en-28-yl)glycinate was 8%.     

白念珠菌角鲨烯环氧化酶基因开放读框的克隆及其在大肠杆菌中的表达*

根据白念珠菌角鲨烯环氧化酶基因的开放读框中编码1MSSVKY6的序列和编码492NEIVR496的序列分别设计上、下游引物,以白念珠菌ATCC11006的基因组DNA为模板进行PCR扩增;将PCR产物克隆并做序列分析后,在大肠杆菌中进行表达。结果表明PCR获得大小约为1.5kb的产物,测序分析表明克隆的产物大小为1491bp,正是白念珠菌角鲨烯环氧化酶基因的开放读框,表达得到约为80kDa大小的蛋白,与理论计算一致。本研究为开展特比萘芬与其作用靶酶关系的研究奠定了基础。     

Synthesis of pro-apoptotic indapamide derivatives as anticancer agents

Abstract

4-Chloro-3-({[(substitutedamino)carbonothioyl]amino}sulfonyl)-N-(2-methyl-2,3-dihydro-1H-indole-1-yl)benzamide (1–20) and 4-chloro-3-({[3-(substituted)-4-oxo-1,3-thiazolidine-2-ylidene]amino}sulfonyl)-N-(2-methyl-2,3-dihydro-1H-indole-1-yl)benzamide derivatives (21–31) were synthesized from 4-chloro-N-(2-methyl-2,3-dihydroindol-1-yl)-3-sulfamoylbenzamide (indapamide). 4-Chloro-3-({[(4-chlorophenyl) amino) carbonothioyl]amino}sulfonyl)-N-(2-methyl-2,3-dihydro-1H-indole-1-yl)benzamide 12 demonstrated the highest proapoptotic activity among all synthesized compounds on melanoma cell lines MDA–MB-435 with 3.7% growth inhibition at the concentration of 10?µM. Compound 12 (SGK 266) was evaluated in vitro using the MTT colorimetric method against melanoma cancer cell line MDA–MB435 growth inhibition for different doses and exhibited anticancer activity with IC₅₀ values of 85–95?µM against melanoma cancer cell line MDA–MB435. In addition, this compound was investigated as inhibitors of four physiologically relevant human carbonic anhydrase isoforms, hCA I, II, IX and XII. The compund inhibited these enzymes with IC₅₀ values ranging between 0.72 and 1.60?µM.     

Dual Localization of Squalene Epoxidase, Erg1p, in Yeast Reflects a Relationship between the Endoplasmic Reticulum and Lipid Particles

Squalene epoxidase, encoded by the ERG1 gene in yeast, is a key enzyme of sterol biosynthesis. Analysis of subcellular fractions revealed that squalene epoxidase was present in the microsomal fraction (30,000 × g) and also cofractionated with lipid particles. A dual localization of Erg1p was confirmed by immunofluorescence microscopy. On the basis of the distribution of marker proteins, 62% of cellular Erg1p could be assigned to the endoplasmic reticulum and 38% to lipid particles in late logarithmic-phase cells. In contrast, sterol Δ²⁴-methyltransferase (Erg6p), an enzyme catalyzing a late step in sterol biosynthesis, was found mainly in lipid particles cofractionating with triacylglycerols and steryl esters. The relative distribution of Erg1p between the endoplasmic reticulum and lipid particles changes during growth. Squalene epoxidase (Erg1p) was absent in an erg1 disruptant strain and was induced fivefold in lipid particles and in the endoplasmic reticulum when the ERG1 gene was overexpressed from a multicopy plasmid. The amount of squalene epoxidase in both compartments was also induced approximately fivefold by treatment of yeast cells with terbinafine, an inhibitor of the fungal squalene epoxidase. In contrast to the distribution of the protein, enzymatic activity of squalene epoxidase was only detectable in the endoplasmic reticulum but was absent from isolated lipid particles. When lipid particles of the wild-type strain and microsomes of an erg1 disruptant were mixed, squalene epoxidase activity was partially restored. These findings suggest that factor(s) present in the endoplasmic reticulum are required for squalene epoxidase activity. Close contact between lipid particles and endoplasmic reticulum may be necessary for a concerted action of these two compartments in sterol biosynthesis.     

Inhibition by prostacyclin and carbacyclins of endothelin-induced DNA synthesis in cultured vascular smooth muscle cells

Effects of prostacyclin and carbacyclins on endothelin-induced DNA synthesis were investigated in vascular smooth muscle cells. DNA synthesis was estimated by [3H]thymidine incorporation. Five carbacyclins used in this report were 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo [3.3.0]oct-2-en-3-yl) pentanoic acid (TEI-7165), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo[3.3.0]oct-2-en-3- yl]pentanoate (TEI-9090), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1-nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)penta noic acid (TEI-9063), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1- nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)pentanoate (TEI-1324), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-4-hydroxy-4-methyl-1- octenyl]bicyclo[3.3.0]oct-2-en-3-yl] pentanoic acid (TEI-3356). Prostacyclin and the carbacyclins inhibited the endothelin-induced DNA synthesis within the nanomolar range. These results suggest that prostacyclin and carbacyclins are possibly effective in inhibiting the proliferation of vascular smooth muscle cells under some situations in vivo.     

Design,synthesis and pharmacological evaluation of novel naphthalenic derivatives as selective MT1 melatoninergic ligands

Novel heterodimer analogues of melatonin were synthesized, when agomelatine (1) and various aryl units are linked via a linear alkyl chain through the methoxy group. The compounds were tested for their actions at melatonin receptors. Several of these ligands are MT₁-selective with nanomolar or subnanomolar affinity. In addition, while most of the derivatives behave as partial agonists on one or both receptor subtypes, N-[2-(7-{4-[6-(1-methoxycarbonylethyl)naphthalen-2-yloxy]butoxy}naphthalen-1-yl)ethyl]acetamide (36), a subnanomolar MT₁ ligand with an 11-fold preference over MT₂ receptors, is a full antagonist on both receptors. Our results also confirm that the selectivity seen for the MT₁ receptor arises predominantly from steric factors and is not a consequence of the bridging of melatonin receptor dimers.     

The first radiosynthesis of [11C]AZD8931 as a new potential PET agent for imaging of EGFR,HER2 and HER3 signaling

The reference standard AZD8931{2-(4-((4-((3-chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl)oxy)piperidin-1-yl)-N-methylacetamide} (11a) was synthesized from methyl 4,5-dimethoxy-2-nitrobenzoate or ethyl 4,5-dimethoxy-2-nitrobenzoate and 2-chloro-N-methylacetamide in 11 steps with 2–5% overall chemical yield. The precursor N-desmethyl-AZD8931{2-(4-((4-((3-chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl)oxy)piperidin-1-yl)acetamide} (11b) was synthesized from methyl 4,5-dimethoxy-2-nitrobenzoate or ethyl 4,5-dimethoxy-2-nitrobenzoate and 2-bromoacetamide in 11 steps with 2–4% overall chemical yield. The target tracer [¹¹C]AZD8931 {2-(4-((4-((3-chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl)oxy)piperidin-1-yl)-N-[¹¹C]methylacetamide} ([¹¹C]11a) was prepared from N-desmethyl-AZD8931 (11b) with [¹¹C]CH₃OTf under basic condition (NaH) through N-[¹¹C]methylation and isolated by HPLC combined with solid-phase extraction (SPE) in 40–50% radiochemical yield based on [¹¹C]CO₂ and decay corrected to end of bombardment (EOB) with 370–1110 GBq/μmol specific activity at EOB.     

Novel 2-[(benzylamino)methyl]pyrrolidine-3,4-diol derivatives as α-mannosidase inhibitors and with antitumor activities against hematological and solid malignancies

Novel α-mannosidase inhibitors of the type (2R,3R,4S)-2-({[(1R)-2-hydroxy-1-arylethyl]amino}methyl)pyrrolidine-3,4-diol have been prepared and assayed for their anticancer activities. Compound 30 with the aryl group = 4-trifluoromethylbiphenyl inhibits the proliferation of primary cells and cell lines of different origins, irrespective of Bcl-2 expression levels, inducing a G2/Mcell cycle arrest and by modification of genes involved in cell cycle progression and survival.     

Synthesis and NMR properties of novel 5,6-dihydroborauracil derivatives

Novel boron compounds - 5,6-saturated borauracil derivatives (4-bromo-5,6-dihydroborauracil, 4-hydroxy-5,6-dihydroborauracil and 4-methoxy-5,6-dihydroborauracil) are presented along with other boron compounds obtained from N-vinylurea: N-substituted β-boronic amino acid - 2-{[(dihydroxyborano-amino)(dihydroxyboranooxy)methyl]-amino}ethylboronic acid and substituted methoxy-borane O-[(1-amino-1-N-vinylamino)methyl]dihydroxyboronate.     

Synthesis,molecular modelling,and preliminary anticonvulsant activity evaluation of novel naphthalen-2-yl acetate and 1,6-dithia-4,9-diazaspiro [4.4] nonane-3,8-dione derivatives

The synthesis, pharmacological evaluation and molecular modelling study of novel naphthalen-2-yl acetate and 1,6-dithia-4,9-diazaspiro [4.4]nonane-3,8-dione derivatives as potential anticonvulsant agents are described. The newly synthesized compounds were characterized by both analytical and spectral data. Alkylation of 1H-imidazole or substituted piperazine with 1-(2-naphthyl)-2-bromoethanone (2) gave naphthalen-2-yl 2-(1H-imidazol-1-yl) acetate (3) and naphthalen-2-yl 2-(substituted piperazin-1-yl) acetate (4–8). Moreover, condensation of naphthalen-2-yl 2-bromoacetate or 2-bromo-1-(naphthalen-2-yl) ethanone with hydrazine hydrate and acetylacetone resulted in the formation of the cyclic pyrazole products 9 and 13. Sonication of naphthalen-2-yl acetate (1) with 2-chloropyridine, 2-chloropyrimidine and 2-(chloromethyl) oxirane gave naphthalen-2-yl 2-(pyridin-2-yl) acetate (10), naphthalen-2-yl 2-(pyrimidin-2-yl) acetate (11) and naphthalen-2-yl-3-(oxiran-2-yl) propanoate (12) respectively. Cyclocondensation reaction of 2-iminothiazolidin-4-one (14) with thioglycolic acid, thiolactic acid and thiomalic acid gave 1,6-dithia-4,9-diazaspiro [4.4]nonane-3,8-dione derivatives (15–17). The compounds were tested in vivo for the anticonvulsant activity by delaying strychnine-induced seizures. The diazaspirononane (17) and 1-(2-naphthyl)-2-bromoethanone (2) showed a high significant delay in the onset of convulsion and prolongation of survival time compared to phenobarbital. The molecular modelling study of anticonvulsant activity of synthesized compounds showed a CNS depressant activity via modulation of benzodiazepine allosteric site in GABA-A receptors.     

Novel semicarbazones based 2,5-disubstituted-1,3,4-oxadiazoles: One more step towards establishing four binding site pharmacophoric model hypothesis for anticonvulsant activity

A series of novel N¹-{5-[(naphthalene-2-yloxy)methyl]-1,3,4-oxadiazol-2-yl}-N⁴-(4-substitutedbenzaldehyde)-semicarbazone, N¹-{5-[(naphthalene-2-yloxy)methyl]-1,3,4-oxadiazol-2-yl}-N⁴-[1-(4-substitutedphenyl)ethanone]-semicarbazone and N¹-{5-[(naphthalene-2-yloxy)methyl]-1,3,4-oxadiazol-2-yl}-N⁴-[1-(4-substitutedphenyl) (phenyl) methanone]-semicarbazone were designed and synthesized on the basis of semicarbazone based pharmacophoric model to meet the structural requirements necessary for anticonvulsant activity. The anticonvulsant activities of the compounds were investigated using maximal electroshock seizure (MES), subcutaneous pentylenetrtrazole (scPTZ) and subcutaneous strychnine (scSTY) models. Some of the selected active compounds were subjected to GABA assay to confirm their mode of action. The efforts were also made to establish structure activity relationships among synthesized compounds. The results of the present studying validated that the pharmacophoric model with four binding sites is essential for anticonvulsant activity.     

A molecular modeling based screening for potential inhibitors to alpha hemolysin from Staphylococcus aureus

Staphylococcus aureus, a Gram-positive bacterium is pathogenic in nature. It is known that secreted toxins remain active after antibiotic treatment. The alpha hemolysin or alpha toxin damages cell membrane and induces apoptosis and degradation of DNA. The titer of alphahemolysin increases and causes hemostasis disturbances, thrombocytopenia, and pulmonary lesions during staphylococcal infection. Therefore, it is of interest to inhibit alpha hemolysin using novel compounds. We used the structure of alpha hemolysin(PDB: 7AHL) to screen structures for 100,000 compounds from the ZINC database using molecular docking with AutoDock VINA. Nine (9) successive hits were then subjected for pharmacokinetic and toxicity properties by PROTOX (a webserver for the prediction of oral toxicities of small molecules) and FAFDrugs (a tool for prediction of ADME and Toxicity). This exercise further identified hit #1 ({[3a-(Dihydroxymethyl)-6-hydroxy-2,2-dimethyl-1,3,4-trioxatetrahydro-2H-pentalen-5- yl]methyl}amino(9H-fluoren-9-yl)acetate with binding affinity: -10.3 kcal/mol) and hit #2 (6-(Dihydroxymethyl)-2-{2-[3- (methylamino)propyl]-2-azatricyclo[9.4.0.03,8]pentadeca-1(11),3,5,7,12,14-hexaen-6-yloxy}tetrahydro-2H-pyran-3,4,5-triol with binding affinity: -9.6 kcal/mol) with acceptable toxicity and ADME properties for potential predicted hemolysin inhibition. These compounds should then be evaluated in vitro using inhibitory studies.     

Microwave-assisted synthesis of 4'-azaflavones and their N-alkyl derivatives with biological activities

4'-Azaflavone (=2-(pyridin-4-yl)-4H-1-benzopyran-4-one; 4) and 3-[(pyridin-4-yl)methyl]-4'-azaflavone (5) were synthesized by a simple environmentally friendly microwave-assisted one-pot method through the cyclization of 3-hydroxy-1-(2-hydroxyphenyl)-3-(pyridin-4-yl)propan-1-one (1), (E)-2'-hydroxy-4-azachalcone (2; chalcone=1,3-diphenylprop-2-en-1-one), and 2'-hydroxy-2-[(hydroxy)(pyridin-4-yl)methyl]-4'-azachalcone (3) under solventless conditions using silica-supported NaHSO(4), followed by treatment with base. In addition, N-alkyl-substituted 4'-azaflavonium bromides 6 and 7 were prepared from compounds 4 and 5, respectively. The antimicrobial and antioxidant activities of compounds 1-7 were tested. The N-alkyl-substituted 4'-azaflavonium bromides 6 and 7 showed high antimicrobial activity against the Gram-positive bacteria and the fungus tested, with MIC values close to those of reference antimicrobials ampicilline and fluconazole. The alkylated compounds 6 and 7 also showed a good antioxidant character in the two antioxidant methods, DPPH (=1,1-diphenyl-2-picrylhydrazyl) radical-scavenging and ferric reducing/antioxidant power (FRAP) tests.     

Design,synthesis and SAR exploration of tri-substituted 1,2,4-triazoles as inhibitors of the annexin A2–S100A10 protein interaction

Recent target validation studies have shown that inhibition of the protein interaction between annexin A2 and the S100A10 protein may have potential therapeutic benefits in cancer. Virtual screening identified certain 3,4,5-trisubstituted 4H-1,2,4-triazoles as moderately potent inhibitors of this interaction. A series of analogues were synthesized based on the 1,2,4-triazole scaffold and were evaluated for inhibition of the annexin A2–S100A10 protein interaction in competitive binding assays. 2-[(5-{[(4,6-Dimethylpyrimidin-2-yl)sulfanyl]methyl}-4-(furan-2-ylmethyl)-4H-1,2,4-triazol-3-yl)sulfanyl]-N-[4-(propan-2-yl)phenyl]acetamide (36) showed improved potency and was shown to disrupt the native complex between annexin A2 and S100A10.     

The role of the oximes HI-6 and HS-6 inside human acetylcholinesterase inhibited with nerve agents: a computational study

The oximes 4-carbamoyl-1-[({2-[(E)-(hydroxyimino) methyl] pyridinium-1-yl} methoxy) methyl] pyridinium (known as HI-6) and 3-carbamoyl-1-[({2-[(E)-(hydroxyimino) methyl] pyridinium-1-yl} methoxy) methyl] pyridinium (known as HS-6) are isomers differing from each other only by the position of the carbamoyl group on the pyridine ring. However, this slight difference was verified to be responsible for big differences in the percentual of reactivation of acetylcholinesterase (AChE) inhibited by the nerve agents tabun, sarin, cyclosarin, and VX. In order to try to find out the reason for this, a computational study involving molecular docking, molecular dynamics, and binding energies calculations, was performed on the binding modes of HI-6 and HS-6 on human AChE (HssAChE) inhibited by those nerve agents.     

Dihydrostilbene derivatives plus kinsenoside from the roots of the rare species Bipinnula fimbriata (Poepp.) I.M.Johnst.

The phytochemical study of the alcoholic extract obtained from Bipinnula fimbriata (Poepp.) I.M.Johnst., allowed to isolate three metabolites, corresponding to the butanolide kinsenoside (1) and to two dihydrostilbene derivatives, which have been assigned as 3-methoxy-5-{2-[3-methoxy-2-(3-methylbut-2-en-1-yl)-phenyl]ethyl}phenol (2) and 4-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-(3-methylbut-2-en-1-yl)phenol, also named cannabistilbene I (3). The occurrence of these compounds is consistent with the current classification of the genus and allowed to point out some chemotaxonomic considerations.     

Inhibition of squalene synthase and squalene epoxidase in tobacco cells triggers an up-regulation of 3-hydroxy-3-methylglutaryl coenzyme a reductase

To get some insight into the regulatory mechanisms controlling the sterol branch of the mevalonate pathway, tobacco (Nicotiana tabacum cv Bright Yellow-2) cell suspensions were treated with squalestatin-1 and terbinafine, two specific inhibitors of squalene synthase (SQS) and squalene epoxidase, respectively. These two enzymes catalyze the first two steps involved in sterol biosynthesis. In highly dividing cells, SQS was actively expressed concomitantly with 3-hydroxy-3-methylglutaryl coenzyme A reductase and both sterol methyltransferases. At nanomolar concentrations, squalestatin was found to inhibit efficiently sterol biosynthesis as attested by the rapid decrease in SQS activity and [(14)C]radioactivity from acetate incorporated into sterols. A parallel dose-dependent accumulation of farnesol, the dephosphorylated form of the SQS substrate, was observed without affecting farnesyl diphosphate synthase steady-state mRNA levels. Treatment of tobacco cells with terbinafine is also shown to inhibit sterol synthesis. In addition, this inhibitor induced an impressive accumulation of squalene and a dose-dependent stimulation of the triacylglycerol content and synthesis, suggesting the occurrence of regulatory relationships between sterol and triacylglycerol biosynthetic pathways. We demonstrate that squalene was stored in cytosolic lipid particles, but could be redirected toward sterol synthesis if required. Inhibition of either SQS or squalene epoxidase was found to trigger a severalfold increase in enzyme activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, giving first evidence for a positive feedback regulation of this key enzyme in response to a selective depletion of endogenous sterols. At the same time, no compensatory responses mediated by SQS were observed, in sharp contrast to the situation in mammalian cells.