Crystal Structure of the Apo and the ADP-Bound Form of Choline Kinase from Plasmodium falciparum

Among the malaria-causing parasites, the deadliest isPlasmodium falciparum, which accounts for the majority of the fatalities. As the infection progresses inside erythrocytes, major cellular and metabolic changes take place. For its own growth, the parasite relies on the accumulation of phospholipids, which are essential for membrane synthesis. Within the Kennedy pathway, theP. falciparumcholine kinase (PfChoK) has a central role in the biosynthesis of phosphatidylcholine and its selective inhibition leads to the parasite arrest and eradication. Here, we report the crystal structure of the apo and the ADP-bound form of choline kinase fromPlasmodium falciparumat 2.0 and 2.2 angstrom resolution, respectively. These new structural data will facilitate the implementation of effective structure-based drug development strategies against PfChoK in the fight against malaria

New Compounds with Bioisosteric Replacement of Classic Choline Kinase Inhibitors Show Potent Antiplasmodial Activity

In the fight against Malaria, new strategies need to be developed to avoid resistance of the parasite to pharmaceutics and other prevention barriers. Recently, a Host Directed Therapy approach based on the suppression of the starting materials uptake from the host by the parasite has provided excellent results. In this article, we propose the synthesis of bioisosteric compounds that are capable of inhibiting Plasmodium falciparum Choline Kinase and therefore to reduce choline uptake, which is essential for the development of the parasite. Of the 41 bioisosteric compounds reported herein, none showed any influence of the linker on the antimalarial and enzyme inhibitory activity, whereas an effect of the type of cationic heads used could be observed. SARs determined that the thienopyrimidine substituted in 4 by a pyrrolidine is the best scaffold, independently of the chosen linker. The decrease in lipophilicity seems to improve the antimalarial activity but to cause an opposite effect on the inhibition of the enzyme. While potent compounds with similar good inhibitory values have been related to the proposed mechanism of action, some of them still show discrepancies and further studies are needed to determine their specific molecular target

3-hydroxy-L-kynurenamine is an immunomodulatory biogenic amine

Tryptophan catabolism is a major metabolic pathway utilized by several professional and non-professional antigen presenting cells to maintain immunological tolerance. Here we report that 3-hydroxy-l-kynurenamine (3-HKA) is a biogenic amine produced via an alternative pathway of tryptophan metabolism. In vitro, 3-HKA has an anti-inflammatory profile by inhibiting the IFN-gamma mediated STAT1/NF-kappa Beta pathway in both mouse and human dendritic cells (DCs) with a consequent decrease in the release of pro-inflammatory chemokines and cytokines, most notably TNF, IL-6, and IL12p70. 3-HKA has protective effects in an experimental mouse model of psoriasis by decreasing skin thickness, erythema, scaling and fissuring, reducing TNF, IL-1 beta, IFN-gamma, and IL-17 production, and inhibiting generation of effector CD8(+) T cells. Similarly, in a mouse model of nephrotoxic nephritis, besides reducing inflammatory cytokines, 3-HKA improves proteinuria and serum urea nitrogen, overall ameliorating immune-mediated glomerulonephritis and renal dysfunction. Overall, we propose that this biogenic amine is a crucial component of tryptophan-mediated immune tolerance. 3-hydroxy-L-kynurenamine (3-HKA) is a metabolite deriving from a lateral pathway of tryptophan catabolism. Here the authors identify 3-HKA as a biogenic amine and show it has anti-inflammatory properties that can protect mice against psoriasis and nephrotoxic nephritis.Peer reviewe

Synthesis and biological evaluation of a new series of 2-amino-3-aroyl thiophene derivatives as agonist allosteric modulators of the A1 adenosine receptor. A position-dependent effect study

The 2-amino-3-(p-chlorobenzoyl)thiophene scaffold has been widely employed as a pharmacophore for the identification of small molecules acting as allosteric modulators at the adenosine A1 receptor. A new series of 2-amino-3-(p-chlorobenzoyl)-4-benzyl-5-arylthiophene derivatives, characterized by the absence as well as the presence of electron-releasing or electron-withdrawing groups on the phenyl ring at the 4- and 5-positions of the thiophene ring, were identified as positive allosteric enhancers at the adenosine A1 receptor in binding (saturation, competition and dissociation kinetics) and functional assays. To better understand the positional requirements of substituents on the 2-amino-3-(p-chlorobenzoyl)thiophene core, the corresponding regioisomeric 4-aryl-5-benzylthiophene analogues were synthesized and found to possess reduced allosteric enhancer activity

Synthesis and biological evaluation of alpha-bromoacryloylamido indolyl pyridinyl propenones as potent apoptotic inducers in human leukaemia cells

The combination of two pharmacophores into a single molecule represents one of the methods that can be adopted for the synthesis of new anticancer molecules. To investigate the influence of the position of the pyridine nitrogen on biological activity, two different series of α-bromoacryloylamido indolyl pyridinyl propenones 3a-h and 4a-d were designed and synthesized by a pharmacophore hybridization approach and evaluated for their antiproliferative activity against a panel of six human cancer cell lines. These hybrid molecules were prepared to combine the α-bromoacryloyl moiety with two series of indole-inspired chalcone analogues, possessing an indole derivative and a 3- or 4-pyridine ring, respectively, linked on either side of 2-propen-1-one system. The structure-activity relationship was also investigated by the insertion of alkyl or benzyl moieties at the N-1 position of the indole nucleus. We found that most of the newly synthesized displayed high antiproliferative activity against U-937, MOLT-3, K-562, and NALM-6 leukaemia cell lines, with one-digit to double-digit nanomolar IC50values. The antiproliferative activities of 3-pyridinyl derivatives 3f-h revealed that N-benzyl indole analogues generally exhibited lower activity compared to N-H or N-alkyl derivatives 3a-b and 3c-e, respectively. Moreover, cellular mechanism studies elucidated that compound 4a induced apoptosis along with a decrease of mitochondrial membrane potential and activated caspase-3 in a concentration-dependent manner

Synthesis and biological evaluation of 2-(3 ',4 ',5 '-trimethoxybenzoyl)-3-aryl/arylaminobenzo[b]thiophene derivatives as a novel class of antiproliferative agents

The biological importance of microtubules in mitosis, as well as in interphase, makes them an interesting target for the development of anticancer agents. Small molecules such as benzo[b]thiophenes are attractive as inhibitors of tubulin polymerization. Thus, a new class of compounds that incorporated the structural motif of the 2-(3',4',5'-trimethoxybenzoyl)-3-aryl/arylamino benzo[b]thiophene molecular skeleton, with electron-donating (Me, OMe, SMe or OEt) or electron-withdrawing (F and Cl) substituents on the B-ring, was synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization and cell cycle effects. The most promising compound in this series was 2-(3',4',5'-trimethoxybenzoyl)-3-(4'-ethoxyphenyl)-benzo[b]thiophene (4e), which significantly inhibited cancer cell growth at submicromolar concentrations, especially against HeLa and Jurkat cells, and interacted with tubulin. As determined by flow cytometric analysis, 4e caused G2/M phase arrest and apoptosis in a time- and concentration-dependent manner. The block in G2/M was correlated with increased expression of cyclin B1 and phosphorylation of cdc25c. Moreover, 4e perturbed mitochondrial membrane potential and caused activation of caspase-3 and cleavage of poly(ADP-rybose)polymerase (PARP), events that are involved in 4e-induced apoptosis

Microwave-assisted synthesis of substituted 2,4-diarylthiazoles and their evaluation as anticancer agents

The microwave-promoted cyclization method has been used for the synthesis of a series of novel substituted 2,4-diarylthiazoles from -halo ketones and thioamides using ethanol as solvent. This rapid method produces compds. in good yield within one minute in comparison with conventional heating method. The synthesized mols. have been evaluated for their antiproliferative effects against five different cancer cell lines

Symmetrical alpha-bromoacryloylamido diaryldienone derivatives as a novel series of antiproliferative agents. Design, synthesis and biological evaluation.

none9In a continuing study of hybrid compounds containing the alpha-bromoacryloyl moiety as potential anticancer drugs, we synthesized a novel series of hybrids 4a-h, in which this moiety was linked to a 1,5-diaryl-1,4-pentadien-3-one system. Many of the conjugates prepared (4b, 4c, 4e and 4g) demonstrated pronounced, submicromolar antiproliferative activity against four cancer cell lines. Moreover, compound 4b induced apoptosis through the mitochondrial pathway and activated caspase-3 in a concentration-dependent manner.noneROMAGNOLI R; BARALDI PG; CRUZ-LOPEZ O; LOPEZ CARA C; CARRION MD; BALZARINI J; HAMEL E; BASSO G; BORTOLOZZI R.; VIOLA GRomagnoli, R; Baraldi, Pg; CRUZ LOPEZ, O; LOPEZ CARA, C; Carrion, Md; Balzarini, J; Hamel, E; Basso, Giuseppe; Bortolozzi, R.; Viola, G

Symmetrical alpha-bromoacryloylamido diaryldienone derivatives as a novel series of antiproliferative agents. Design, synthesis and biological evaluation

In a continuing study of hybrid compounds containing the alpha-bromoacryloyl moiety as potential anticancer drugs, we synthesized a novel series of hybrids 4a-h, in which this moiety was linked to a 1,5-diaryl-1,4-pentadien-3-one system. Many of the conjugates prepared (4b, 4c, 4e and 4g) demonstrated pronounced, submicromolar antiproliferative activity against four cancer cell lines. Moreover, compound 4b induced apoptosis through the mitochondrial pathway and activated caspase-3 in a concentration-dependent manner.status: publishe

Synthesis and Antitumor Activity of 1,5-Disubstituted 1,2,4-Triazoles as Cis-Restricted Combretastatin Analogues

A series of 1-aryl-5-(3′,4′,5′-trimethoxyphenyl) derivatives and their related 1-(3′,4′,5′-trimethoxyphenyl)-5-aryl-1,2,4-triazoles, designed as cis-restricted combretastatin analogues, were synthesized and evaluated for antiproliferative activity, inhibitory effects on tubulin polymerization, cell cycle effects, and apoptosis induction. Their activity was greater than, or comparable with, that of the reference compound CA-4. Flow cytometry studies showed that HeLa and Jurkat cells treated with the most active compounds 4l and 4o were arrested in the G2/M phase of the cell cycle in a concentration dependent manner. This effect was accompanied by apoptosis of the cells, mitochondrial depolarization, generation of reactive oxygen species, activation of caspase-3, and PARP cleavage. Compound 4l was also shown to have potential antivascular activity, since it induced endothelial cell shape change in vitro and disrupted the sprouting of endothelial cells in the chick aortic ring assay