Activation of Caspase-6 Is Promoted by a Mutant Huntingtin Fragment and Blocked by an Allosteric Inhibitor Compound.

Aberrant activation of caspase-6 (C6) in the absence of other hallmarks of apoptosis has been demonstrated in cells and tissues from patients with Huntington disease (HD) and animal models. C6 activity correlates with disease progression in patients with HD and the cleavage of mutant huntingtin (mHTT) protein is thought to strongly contribute to disease pathogenesis. Here we show that the mHTT1-586 fragment generated by C6 cleavage interacts with the zymogen form of the enzyme, stabilizing a conformation that contains an active site and is prone to full activation. This shift toward enhanced activity can be prevented by a small-molecule inhibitor that blocks the interaction between C6 and mHTT1-586. Molecular docking studies suggest that the inhibitor binds an allosteric site in the C6 zymogen. The interaction of mHTT1-586 with C6 may therefore promote a self-reinforcing, feedforward cycle of C6 zymogen activation and mHTT cleavage driving HD pathogenesis.

Blood schizontocidal and gametocytocidal activity of 3-hydroxy-N'-arylidenepropanehydrazonamides: a new class of antiplasmodial compounds.

3-Hydroxy-N'-arylidenepropanehydrazonamides represent a new class of antiplasmodial compounds. The two most active phenanthrene-based derivatives showed potent in vitro antiplasmodial activity against the 3D7 (sensitive) and Dd2 (multidrug-resistant) strains of Plasmodium falciparum with nanomolar IC50 values in the range of 8-28 nM. Further studies revealed that the most promising derivative, bearing a 4-fluorobenzylidene moiety, demonstrated in vivo antiplasmodial activity after oral administration in a P. berghei malaria model, although no complete parasite elimination was achieved with a four-dose regimen. The in vivo efficacy correlated well with the plasma concentration levels, and no acute toxicity symptoms (e.g., death or changes in general behavior or physiological activities) were observed, which is in agreement with a >1000-fold lower activity against L6 cells, a primary cell line derived from mammalian (rat) skeletal myoblasts. This indicates that lead compound 29 displays selective activity against P. falciparum. Moreover, both phenanthrene-based derivatives were active against stage IV/V gametocytes of P. falciparum in vitro.

N-(1-Allyl-1H-indazol-5-yl)-4-meth-oxy-benzene-sulfonamide hemihydrate.

In the title compound, C17H17N3O3 (.)0.5H2O, the indazole system makes a dihedral angle of 46.19 (8)° with the plane through the benzene ring and is nearly perpendicular to the allyl group, as indicated by the dihedral angle of 81.2 (3)°. In the crystal, the water mol-ecule, disordered over two sites related by an inversion center, forms O-H⋯N bridges between indazole N atoms of two sulfonamide mol-ecules. It is also connected via N-H⋯O inter-action to the third sulfonamide mol-ecule; however, due to the water mol-ecule disorder, only every second mol-ecule of sulfonamide participates in this inter-action. This missing inter-action results in a slight disorder of the sulfonamide S,O and N atoms which are split over two sites with half occupancy. With the help of C-H⋯O hydrogen bonds, the mol-ecules are further connected into a three-dimensional network.

4-Meth-oxy-N-(1-methyl-1H-indazol-5-yl)benzene-sulfonamide.

The indazole ring system [maximum deviation = 0.013 (2) Å] of the title compound, C15H15N3O3S, makes a dihedral angle of 50.11 (7)° with the benzene ring. In the crystal, cohesion is provided by C-H⋯O and N-H⋯N hydrogen bonds, which link the molecules into chains propagating along the b-axis direction.

Synthesis, antiproliferative and apoptotic activities of N-(6(4)-indazolyl)-benzenesulfonamide derivatives as potential anticancer agents.

Recently, it has been reported that compounds bearing a sulfonamide moiety possess many types of biological activities, including anticancer activity. The present work reports the synthesis and antiproliferative evaluation of some N-(6(4)-indazolyl)benzenesulfonamides and 7-ethoxy-N-(6(4)-indazolyl)benzenesulfonamides. All compounds were evaluated for their in vitro antiproliferative activity against three tumor cell lines: A2780 (human ovarian carcinoma) A549 (human lung adenocarcinoma) and P388 (murine leukemia). The results indicated that sulfonamides 2c, 3c, 6d, 8, 13, 3b and 16 were endowed with a pharmacologically interesting antiproliferative activity with compounds 2c and 3c showing the lower IC(50) (from 0.50 ± 0.09 to 1.83 ± 0.52 µM and from 0.58 ± 0.17 to 5.83 ± 1.83 µM, respectively). Moreover, these indazoles were able to trigger apoptosis through the upregulation of the typical apoptosis markers p53 and bax. As regard to the hypothetic targets of these compounds, a preliminary docking analysis showed that all compounds seemed to interact with ß-tubulin, in particular compound 3b that showed the lower Ki. The cytofluorimetric analysis of the cell cycle phases indicates that all compounds, when administered at their IC(75), caused a block in the G2/M phase of the cell cycle with the generation of subpopulations of cells with a number of chromosome >4n. When the IC(50)s were applied we observed a prevalent block in the G0/G1 phase except for compounds 16 and 8 where a partial G2/M block was present with a concomitant decrease of cells in the G0/G1 and S phases of the cell cycle. Altogether these results suggest a possible, but not exclusive, interaction with microtubules.

6-Amino-4-(3-iodo-anilino)-2-methyl-pyrimidin-1-ium chloride.

In the cation of the title salt, C(11)H(12)IN(4) (+)·Cl(-), the two aromatic rings are oriented to each other at 9.3 (2)°. In the crystal, the two independent Cl(-) anions lie on twofold rotation axes. N-H⋯Cl hydrogen bonds between the cations and anions generate a supra-molecular layer parallel to (010).

Efficient synthesis and 5-LOX/COX-inhibitory activity of some 3-hydroxybenzo[b]thiophene-2-carboxylic acid derivatives.

A series of 3-hydroxybenzo[b]thiophene-2-carboxylic acid derivatives has been prepared and subsequently evaluated with regards to the inhibition of 5-LOX/COX. Structure optimization furnished derivatives with promising in vitro activity as dual 5-LOX/COX inhibitors with submicromolar IC(50) values for inhibition of 5-LOX and COX-1, respectively.

Ethyl 3-[7-eth-oxy-6-(4-meth-oxy-benzene-sulfonamido)-2H-indazol-2-yl]propano-ate.

In the title compound, C(21)H(25)N(3)O(6)S, the dihedral angle between the meth-oxy-benzene and indazole rings is 74.96 (5)°. The crystal packing is stabilized by an N-H⋯O hydrogen bond into a two-dimensional network. In addition, C-H⋯π inter-actions and a π-π contact, with a centroid-centroid distance of 3.5333 (6) Å, are observed. The crystal packing is stabilized by N-H⋯O and C-H⋯O hydrogen bonds.

2-Eth-oxy-5-methylbis[1,2,4]triazolo[1,5-a:4',3'-c]quinazoline.

The title compound, C(13)H(12)N(6)O, is a functionalized ditriazoloquinazoline with substituted eth-oxy and methyl groups attached at the 2-position of each triazole spacer. The fused-ring system is essentially planar [r.m.s. deviation = 0.016 (2) Å]. In the crystal, a weak C-H⋯N hydrogen bond connects the mol-ecules into a chain along [101].

Erratum: 2-Benz-yloxy-1,2,4-triazolo[1,5-a]quinazolin-5(4H)-one. Corrigendum.

The name of one of the authors in the paper by Al-Salahi et al. [Acta Cryst. (2011), E67, o1861] is corrected.[This corrects the article DOI: 10.1107/S1600536811024962.].

Facile synthesis and in-vitro antimalarial activity of novel α-hydroxy hydrazonates.

A series of previously unreported α-hydroxy hydrazonates were synthesized and tested for their antimalarial properties. Structure optimization of the antiplasmodially active α-hydroxy hydrazonate III furnished derivatives with strong in-vitro antimalarial activity against 3D7 strains of Plasmodium falciparum with IC(50) values lower than 2.0 µM.

A new series of 2-alkoxy(aralkoxy)-[1,2,4]triazolo[1,5-a]quinazolin-5-ones as adenosine receptor antagonists.

This research was carried out to study the pharmacological activity of a newly synthesized series of 2-alkoxy-[1,2,4]triazolo[1,5-a]quinazolin-5-ones as adenosine receptor antagonists. These compounds have been tested in radioligand binding assays on cloned Chinese hamster ovary (CHO) cells transfected with A(1), A(2A), A(2B) and A(3) receptors. In particular, among the triazoloquinazolines (1-11), the dialkoxy derivative (7b) was found to have the highest affinity at A(1) subtype receptor, and its radioligand binding activity together with 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) was studied. Finally, the structure-activity relationship (SAR) studies on the titled compounds provide some new insights about steric hindrance and lipophilic requirements for anchoring to the adenosine receptors recognition site.

Synthesis and antimalarial activity of chain substituted pivaloyloxymethyl ester analogues of Fosmidomycin and FR900098.

Fosmidomycin is a promising antimalarial drug candidate with a unique chemical structure and a novel mode of action. Chain substituted pivaloyloxymethyl ester derivatives of Fosmidomycin and its acetyl analogue FR900098 have been synthesized and their in vitro antimalarial activity versus the Chloroquine sensitive strain 3D7 of Plasmodium falciparum has been determined.