Effects of memantine on mania-like phenotypes exhibited by Drosophila Shaker mutants.

INTRODUCTION: Increased glutamate levels and electrolytic fluctuations have been observed in acutely manic patients. Despite some efficacy of the non-competitive NMDA receptor antagonist memantine (Mem), such as antidepressant-like and mood-stabilizer drugs in clinical studies, its specific mechanisms of action are still uncertain. The present study aims to better characterize the Drosophila melanogaster fly Shaker mutants (SH), as a translational model of manic episodes within bipolar disorder in humans, and to investigate the potential anti-manic properties of Mem. METHODS AND RESULTS: Our findings showed typical behavioral abnormalities in SH, which mirrored with the overexpression of NMDAR-NR1 protein subunit, matched well to glutamate up-regulation. Such molecular features were associated to a significant reduction of SH brain volume in comparison to Wild Type strain flies (WT). Here we report on the ability of Mem treatment to ameliorate behavioral aberrations of SH (similar to that of Lithium), and its ability to reduce NMDAR-NR1 over-expression. CONCLUSIONS: Our results show the involvement of the glutamatergic system in the SH, given the interaction between the Shaker channel and the NMDA receptor, suggesting this model as a promising tool for studying the neurobiology of bipolar disorders. Moreover, our results show Mem as a potential disease-modifying therapy, providing insight on new mechanisms of action.

Selective inhibition of carbonic anhydrase IX and XII by coumarin and psoralen derivatives.

A small library of coumarin and their psoralen analogues EMAC10157a-b-d-g and EMAC10160a-b-d-g has been designed and synthesised to investigate the effect of structural modifications on their inhibition ability and selectivity profile towards carbonic anhydrase isoforms I, II, IX, and XII. None of the new compounds exhibited activity towards hCA I and II isozymes. Conversely, both coumarin and psoralen derivatives were active against tumour associated isoforms IX and XII in the low micromolar or nanomolar range of concentration. These data further corroborate our previous findings on analogous derivatives, confirming that both coumarins and psoralens are interesting scaffolds for the design of isozyme selective hCA inhibitors.

New Dihydrothiazole Benzensulfonamides: Looking for Selectivity toward Carbonic Anhydrase Isoforms I, II, IX, and XII.

In the present study we investigated the structure-activity relationships of a new series of 4-[(3-ethyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulfonamides (EMAC10101a-m). All synthesized compounds, with the exception of compound EMAC10101k, preferentially inhibit off-target hCA II isoform. Within the series, compound EMAC10101d, bearing a 2,4-dichorophenyl substituent in position 4 of the dihydrothiazole ring, was the most potent and selective toward hCA II with an inhibitory activity in the low nanomolar range.

Exploring new structural features of the 4-[(3-methyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzenesulphonamide scaffold for the inhibition of human carbonic anhydrases.

A library of 4-[(3-methyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulphonamides (EMAC8002a-m) was designed and synthesised to evaluate the effect of substituents in the positions 3 and 4 of the dihydrothiazole ring on the inhibitory potency and selectivity toward human carbonic anhydrase isoforms I, II, IX, and XII. Most of the new compounds preferentially inhibit the isoforms II and XII. Both electronic and steric features on the aryl substituent in the position 4 of the dihydrothiazole ring concur to determine the overall biological activity of these new derivatives.

Investigating the Anticancer Activity of Isatin/Dihydropyrazole Hybrids.

A series of isatin-dihydropyrazole hybrids have been synthesized in order to assess their potential as anticancer agents. In particular, 12 compounds were evaluated for their antiproliferative activity toward A549, IGR39, U87, MDA-MB-231, MCF-7, BT474, BxPC-3, SKOV-3, and H1299 cell lines, and human foreskin fibroblasts. Four compounds exhibited interesting antiproliferative activity and were further examined to determine their EC50 values toward a panel of selected tumor cell lines. The best compounds were then investigated for their induced mechanism of cell death. Preliminary structure-activity relationship indicates that the presence of a substituent such as a chlorine atom or a methyl moiety in position 5 of the isatin nucleus is beneficial for the antitumor activity. EMAC4001 proved the most promising compound within the studied series with EC50 values ranging from 0.01 to 0.38 µM.

Tuning the Dual Inhibition of Carbonic Anhydrase and Cyclooxygenase by Dihydrothiazole Benzensulfonamides.

A novel series of of 4-[(3-phenyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulfonamides (EMAC10111a-g) was synthesized and assayed toward both human carbonic anhydrase isozymes I, II, IX, and XII and cyclooxygenase isoforms. The majority of these derivatives preferentially inhibit hCA isoforms II and XII and hCOX-2 isozyme, indicating that 2,3,4-trisubstituted 2,3-dihydrothiazoles are a promising scaffold for the inhibition of hCA isozymes and of hCOX-2 enzyme. The nature of the substituent at the dihydrothiazole ring position 4 influenced the activity and selectivity toward both enzyme families. EMAC10111g resulted as the best performing compound toward both enzyme families and exhibited preferential activity toward hCA XII and hCOX-2 isozymes.

Targeting Tumor Associated Carbonic Anhydrases IX and XII: Highly Isozyme Selective Coumarin and Psoralen Inhibitors.

A small library of psoralen carboxylic acids and their corresponding benzenesulfonamide derivatives were designed and synthesized to evaluate their activity and selectivity toward tumor associated human carbonic anhydrase (hCA) isoforms IX and XII. Both psoralen acids and sulfonamides exhibited potent inhibition of IX and XII isozymes in the nanomolar concentration range. However, psoralen acids resulted as the most selective in comparison with the corresponding benzenesulfonamide derivatives. Our data indicate that the psoralen scaffold is a promising starting point for the design of highly selective tumor associated hCA inhibitors.

N-Acylbenzenesulfonamide Dihydro-1,3,4-oxadiazole Hybrids: Seeking Selectivity toward Carbonic Anhydrase Isoforms.

A series of N-acylbenzenesulfonamide dihydro-1,3,4-oxadiazole hybrids (EMAC8000a-m) was designed and synthesized with the aim to target tumor associated carbonic anhydrase (hCA) isoforms IX and XII. Most of the compounds were selective inhibitors of the tumor associated hCA XII. Moreover, resolution of EMAC8000d racemic mixture led to the isolation of the levorotatory eutomer exhibiting an increase of hCA XII inhibition potency and selectivity with respect to hCA II. Computational studies corroborated these data. Overall our data indicate that both substitution pattern and stereochemistry of dihydro-1,3,4-oxadiazole could be considered as key factors to determine activity and selectivity toward hCA isozymes. These results can provide further indication for the design and optimization of selective hCA inhibitors.

Isatin: a privileged scaffold for the design of carbonic anhydrase inhibitors.

The isatin scaffold is the constitutive fragment of several natural and synthetic bioactive molecules. Albeit several benzene sulphonamide-based carbonic anhydrase inhibitors (CAIs) have been reported, only recently isatin benzene sulphonamides have been studied and proposed as CAIs. In this study we have designed, synthesised, and evaluated the biological activity of a series of differently substituted isatin-based benzene sulphonamides which have been designed for the inhibition of carbonic anhydrase isoforms. The activity of all the synthesised compounds was evaluated towards human carbonic anhydrase I, II, IX, and XII isozymes. Our results indicate that the nature and position of substituents on the isatin ring can modulate both activity and isozyme selectivity.

Nanoparticles from lipid-based liquid crystals: emulsifier influence on morphology and cytotoxicity.

Here, monoolein-based nanoparticles (NPs), obtained through fragmentation of bulk liquid crystalline phases, and stabilized by two different emulsifiers, namely, Pluronic F127 (PF127) and lauroylcholine chloride (LCh), are investigated for structural features and for short-term in vitro cytotoxicity. Depending on the emulsifiers, different morphologies of the lipid NPs (cubosomes and liposomes) are obtained, as demonstrated by cryo-TEM images. Although NPs offer many advantages in medical applications and various chemicals used for their preparation are under investigation, so far there are no standardized procedures to evaluate cell biocompatibility. Two different protocols to evaluate the impact of these lipid NPs on biological systems are presented. Results show that nanoparticles stabilized by PF127 (cubosomes) display a relevant toxicity toward different cell lines, whereas those stabilized by LCh (liposomes) affect cell viability at a much lesser extent.

Orientation and specific interactions of nucleotides and nucleolipids inside monoolein-based liquid crystals.

The entrapment of AMP, GMP, CMP, and UMP nucleotides along with two different AMP-based nucleolipids (hydrophobically functionalized nucleotides) inside the liquid crystalline phases of the monoolein/water system is investigated through optical microscopy, small-angle X-ray diffraction (SAXRD), and nuclear magnetic resonance (NMR) techniques. As ascertained mainly through (31)P NMR experiments, when included within the cubic phase, the various nucleotides undergo a slow hydrolysis of the sugar-phosphate ester bond, induced by specific interactions at the monoolein-water interface. Upon aging, the degradation of the nucleotides causes a cubic-to-hexagonal phase transition. Differently, neither hydrolysis nor alterations of the monoolein self-assembly are observed when the nucleotides are included as lipid derivatives within the cubic liquid crystalline phase. A model that explains both the hydrolysis and the consequent phase transition is presented.