Synthesis and anti-picornaviridae in vitro activity of a new class of helicase inhibitors the N,N'-bis[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl] alkyldicarboxamides.

A series N,N'-bis[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkyldicarboxamides (3a-f and 5a-j) were prepared starting from their already known (1a-d) and (4a-c) or new (4d) amine parents. Because of the antiviral activity of several N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides previously reported, title compounds were evaluated in vitro for cytotoxicity and antiviral activity against viruses representative of Picornaviridae, [i.e. Enterovirus Coxsackie B2 (CVB-2) and Polio (Sb-1)] and of two of the three genera of the Flaviviridae [Bovine Viral Diarrhea Virus (BVDV) and Yellow Fever Virus (YFV)]. Furthermore, because of the in silico activity against the RNA-dependent RNA-helicase of Polio 1 previously reported, title compounds were evaluated against the 3D model of the Sb-1 helicase and against the 2D model of the CVB-2 helicase. As a reference we used the antiviral and in silico activities of an imidazo counterpart of the title compounds, N,N'-bis[4-(2-benzimidazolyl)phenyl]alkyldicarboxamides (III) that other authors reported to be able to inhibit the corresponding enzyme of Hepatitis C Virus (HCV). In cell-based antiviral assays, N,N'-bis[4-(1H-benzotriazol-1-yl)phenyl]alkyldicarboxamides (3a-f) resulted completely inactive whereas the bis-5,6-dimethyl-benzotriazol-2-yl derivatives (5d-f) exhibited good activity against the Enteroviruses, (EC(50)s ranged between 7 and 11 microM against CVB-2 and 19-52 against Sb-1). Interestingly, bis-5,6-dichloro-benzotriazol-2-yl derivatives (5h-j) showed very selective activity against CVB-2 (EC(50)s = 4-11 microM) whereas they resulted completely inactive against all the other viruses screened. In general, all title compounds showed a good cytotoxicity profile in MT-4 cells. Molecular modeling investigations showed that active compounds may interact with the binding site of the Sb-1 helicase and that their free binding energy values are in agreement with their EC(50)s values.

Chemistry, biological properties and SAR analysis of quinoxalinones.

Quinoxaline derivatives have received much attention in recent years owing to their both biological properties and pharmaceutical applications. In this review we focus the attention on quinoxalin-2(3)-ones and quinoxalin-2,3-diones. These derivatives are particularly interesting since some of them showed antimicrobial (against several bacteria, viruses, fungi, etc), or anticancer activities. Furthermore, others are reported to be potent no-NMDA glutamate receptor antagonists, endowed with anxiolytic, deconditioning, analgesic, antispastic, antiallergic, antithrombotic activities. In this article we also report SAR studies and the most important methods of synthesis of the quinoxalin-2(3)-(di)ones.

RAGE Expression and ROS Generation in Neurons: Differentiation versus Damage.

RAGE is a multiligand receptor able to bind advanced glycation end-products (AGEs), amphoterin, calgranulins, and amyloid-beta peptides, identified in many tissues and cells, including neurons. RAGE stimulation induces the generation of reactive oxygen species (ROS) mainly through the activity of NADPH oxidases. In neuronal cells, RAGE-induced ROS generation is able to favor cell survival and differentiation or to induce death through the imbalance of redox state. The dual nature of RAGE signaling in neurons depends not only on the intensity of RAGE activation but also on the ability of RAGE-bearing cells to adapt to ROS generation. In this review we highlight these aspects of RAGE signaling regulation in neuronal cells.

The Nrf2/HO-1 Axis in Cancer Cell Growth and Chemoresistance.

The transcription factor, nuclear factor erythroid 2 p45-related factor 2 (Nrf2), acts as a sensor of oxidative or electrophilic stresses and plays a pivotal role in redox homeostasis. Oxidative or electrophilic agents cause a conformational change in the Nrf2 inhibitory protein Keap1 inducing the nuclear translocation of the transcription factor which, through its binding to the antioxidant/electrophilic response element (ARE/EpRE), regulates the expression of antioxidant and detoxifying genes such as heme oxygenase 1 (HO-1). Nrf2 and HO-1 are frequently upregulated in different types of tumours and correlate with tumour progression, aggressiveness, resistance to therapy, and poor prognosis. This review focuses on the Nrf2/HO-1 stress response mechanism as a promising target for anticancer treatment which is able to overcome resistance to therapies.

Role of Nrf2, HO-1 and GSH in Neuroblastoma Cell Resistance to Bortezomib.

The activation of Nrf2 has been demonstrated to play a crucial role in cancer cell resistance to different anticancer therapies. The inhibition of proteasome activity has been proposed as a chemosensitizing therapy but the activation of Nrf2 could reduce its efficacy. Using the highly chemoresistant neuroblastoma cells HTLA-230, here we show that the strong reduction in proteasome activity, obtained by using low concentration of bortezomib (BTZ, 2.5 nM), fails in reducing cell viability. BTZ treatment favours the binding of Nrf2 to the ARE sequences in the promoter regions of target genes such as heme oxygenase 1 (HO-1), the modulatory subunit of γ-glutamylcysteine ligase (GCLM) and the transporter for cysteine (x-CT), enabling their transcription. GSH level is also increased after BTZ treatment. The up-regulation of Nrf2 target genes is responsible for cell resistance since HO-1 silencing and GSH depletion synergistically decrease BTZ-treated cell viability. Moreover, cell exposure to all-trans-Retinoic acid (ATRA, 3 µM) reduces the binding of Nrf2 to the ARE sequences, decreases HO-1 induction and lowers GSH level increasing the efficacy of bortezomib. These data suggest the role of Nrf2, HO-1 and GSH as molecular targets to improve the efficacy of low doses of bortezomib in the treatment of malignant neuroblastoma.

A combined in silico/in vitro approach unveils common molecular requirements for efficient BVDV RdRp binding of linear aromatic N-polycyclic systems.

In this work, we present and discuss a comprehensive set of both newly and previously synthesized compounds belonging to 5 distinct molecular classes of linear aromatic N-polycyclic systems that efficiently inhibits bovine viral diarrhea virus (BVDV) infection. A coupled in silico/in vitro investigation was employed to formulate a molecular rationale explaining the notable affinity of all molecules to BVDV RNA dependent RNA polymerase (RdRp) NS5B. We initially developed a three-dimensional common-feature pharmacophore model according to which two hydrogen bond acceptors and one hydrophobic aromatic feature are shared by all molecular series in binding the viral polymerase. The pharmacophoric information was used to retrieve a putative binding site on the surface of the BVDV RdRp and to guide compound docking within the protein binding site. The affinity of all compounds towards the enzyme was scored via molecular dynamics-based simulations, showing high correlation with in vitro EC50 data. The determination of the interaction spectra of the protein residues involved in inhibitor binding highlighted amino acids R295 and Y674 as the two fundamental H-bond donors, while two hydrophobic cavities HC1 (residues A221, I261, I287, and Y289) and HC2 (residues V216, Y303, V306, K307, P408, and A412) fulfill the third pharmacophoric requirement. Three RdRp (K263, R295 and Y674) residues critical for drug binding were selected and mutagenized, both in silico and in vitro, into alanine, and the affinity of a set of selected compounds towards the mutant RdRp isoforms was determined accordingly. The agreement between predicted and experimental data confirmed the proposed common molecular rationale shared by molecules characterized by different chemical scaffolds in binding to the BVDV RdRp, ultimately yielding compound 6b (EC50 = 0.3 µM; IC50 = 0.48 µM) as a new, potent inhibitor of this Pestivirus.

Benzotriazole: An overview on its versatile biological behavior.

Discovered in late 1960, azoles are heterocyclic compounds class which constitute the largest group of available antifungal drugs. Particularly, the imidazole ring is the chemical component that confers activity to azoles. Triazoles are obtained by a slight modification of this ring and similar or improved activities as well as less adverse effects are reported for triazole derivatives. Consequently, it is not surprising that benzimidazole/benzotriazole derivatives have been found to be biologically active. Since benzimidazole has been widely investigated, this review is focused on defining the place of benzotriazole derivatives in biomedical research, highlighting their versatile biological properties, the mode of action and Structure Activity Relationship (SAR) studies for a variety of antimicrobial, antiparasitic, and even antitumor, choleretic, cholesterol-lowering agents.

Correlation between cholesterol esterification, MDR1 gene expression and rate of cell proliferation in CEM and MOLT4 cell lines.

A positive correlation between cholesterol esterification and growth rate potential was previously found in our laboratory during the growth of CEM and MOLT4 lymphoblastic cells. In the current study, we investigated whether the rates of cholesterol esters synthesis correlate with changes of acyl-CoAcholesterol acyltransferase (ACAT) mRNA levels and of other genes implied in cholesterol biosynthesis and uptake, such as 3-hydroxy-3-methylglutaryl-CoA (HMGCoA) reductase and low density lipoprotein (LDL) receptor. The results showed that the more rapid growing CEM cells had lower levels of expression of HMGCoA-reductase and LDL receptors compared to MOLT4. By contrast, ACAT mRNA levels were higher in CEM cells, further supporting the concept of a possible involvement of cholesterol esters in the regulation of cell growth and division. In this study, high levels of cholesterol esterification and of expression of ACAT gene were also associated with a markedly increased expression of multidrug resistance (MDR1) gene, suggesting that MDR1 activity might contribute to regulate the rate of cell growth and division by modulating intracellular cholesterol ester levels.

G6PD activity and gene expression in leukemic cells from G6PD-deficient subjects.

In the present study we examined gene expression and glucose-6-phosphate dehydrogenase (G6PD) activity in leukemic cells isolated from G6PD normal and deficient subjects. The results have shown that G6PD activity strongly increases in G6PD normal leukemic cells as well as in G6PD deficient leukemic cells when compared to peripheral blood mononuclear cells (PBMC). Higher levels of G6PD gene expression were observed in leukemic cells from G6PD deficient patients compared to G6PD normal. A similar pattern of gene expression was also observed for 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase. These results support the hypothesis that G6PD deficient cell, in order to sustain their growth, must respond to the low activity of their mutant enzyme with an increase in quantity through an induction of gene expression.

Quinoxaline chemistry. Part 7. 2-[aminobenzoates]- and 2-[aminobenzoylglutamate]-quinoxalines as classical antifolate agents. Synthesis and evaluation of in vitro anticancer, anti-HIV and antifungal activity.

Thirty-three quinoxalines bearing an aminobenzoyl or aminobenzoylglutamate group on position 2 and various substituents on position 3,6,7 of the heterocycle were prepared in order to evaluate in vitro anticancer activity. Preliminary screening performed at NCI showed that most derivatives exhibited a moderate to strong growth inhibition activity on various tumor panel cell lines between 10(-5) and 10(-4) Molar concentrations. Interesting selectivities were also recorded between 10(-8) and 10(-6) M. Among the series examined one compound (29) which was the most active also exhibited both in vitro anti-HIV protection and antifungal activity while in other two (31, 37) the antifungal activity was prevailing.

Synthesis and evaluation of gastroprotective and antiulcer activity of some 2-substituted-1H-imidazo[4,5-b] pyridines and -1H-benzimidazoles.

Several compounds possessing imidazo[4,5-b]pyridine and benzimidazole structure bearing substituents in position 2 were prepared in order to evaluate an anti-ulcer and gastroprotective activity in rat pylorus ligature, in comparison with omeprazole. Among sixteen compounds taken as representatives of the synthetised series only one (3d) showed a good activity by i.m. administration at 50 mg/kg, while by oral administration of 100 mg/kg a certain number was active and in some cases this activity was quite superior to that of omeprazole.

Synthesis and evaluation of gastroprotective activity of omeprazole related benzimidazole, imidazo[4,5-b]pyridine and quinoxaline 2-substituted derivatives.

Twenty compounds possessing benzimidazole, imidazo[4,5-b]pyridine and quinoxaline structure bearing either a substituted arylmethylmercapto- or an arylmethylsulfinyl group in position 2 were prepared in order to evaluate an antiulcer and gastroprotective activity in rat pylorus ligature, in comparison with omeprazole at the dose of 50 mg/kg after i.m. administration. One third of these compounds showed a moderate activity, being about half potent as omeprazole.

Quinoxaline chemistry. Part 6--Synthesis and evaluation of antiulcer and gastroprotective activity of 2-[arylmethylmercapto-, arylmethylsulfinyl-, piperazinyl-3-R-substituted]quinoxalines.

Thirty compounds possessing quinoxaline structure bearing either substituted arylmethylmercapto-, arylmethylsulfinyl group or a piperazinyl moiety in position 2 were prepared in order to evaluate an antiulcer and gastroprotective activity in rat pylorus ligature, in comparison with omeprazole and ranitidine at the dose of 100 mg/kg after oral administration. Among the compounds of the first group one third showed a moderate activity being about half potent as omeprazole whereas in the second group compound 5b exibited an activity superior to that of ranitidine accompanied with the lowest incidence of lesions and mortality and another compound (5i) was equiactive as ranitidine.

Solid lipid nanoparticle preparation by a warm microemulsion based process: influence of microemulsion microstructure.

Warm microemulsions (WME) containing lipids are used as starting systems to obtain solid lipid nanoparticles (SLN) in alternative processes to those based on high pressure homogenization technique. SLN characteristics can be influenced by the microemulsion composition and the specific conditions adopted in the quenching process related to the transformation of WME into nanoparticles. To establish optimized conditions for the production of SLN starting from WME, in a first step of this work we have defined the microstructure of warm microemulsions highlighted in the lecithin (LCT)/water (W)/tripalmitin (TP)/1-butanol (B)/taurocholate sodium salt (ST) phase behavior at 70°C. Moreover, we have further studied the LCT/W/TP/B system by evaluating the effect on the microemulsion area due to the LCT/B weight ratio, the replacement of 1-butanol with different alcohols (ROH), and the addition of taurocholate sodium salt (ST) at different LCT/ST weight ratios. The microstructure of the isotropic phase region obtained in the presence of ST has been characterized by both (1)H NMR PGSE measurements and electrical conductivity. The characteristics of final nanoparticles are discussed taking into account both the microstructure of the parent WME and the conditions of the quenching process leading to SLN. The present results highlight the relevance of the microstructural characteristic of WME to assure the obtainment of SLN with average diameter in the order of 100-2000 nm and narrow size distribution.

[Disseminated Pneumocystis carinii infection: clinico-pathologic findings in an AIDS patient]. / Infezione disseminata da Pneumocystis carinii: reperti clinico-patologici in paziente con AIDS.

Pneumocystis carinii pneumonia (PcP) is the most frequent cause of death in AIDS patients. Systemic diffusion of this microorganism is a rare event, mostly reported in patients receiving prophylactic aerosol therapy. The case here described is relative to a 29 years old man with AIDS, dead short by after hospital admission. Radiological and ecoscan examinations revealed structural subversion of liver and spleen, with frequent parenchymal calcification. Post mortem histological examination of lung, liver, spleen, heart, bone marrow, lymph nodes, kidney and hypophysis identified the presence of Pc, confirmed by monoclonal specified antibody immunostaining.

Cholelithiasis and Gilbert's syndrome in homozygous beta-thalassaemia.

Cholelithiasis has been reported with a variable incidence in homozygous beta-thalassaemia, the reasons for which have only partially been defined. Disease-associated factors or specific modifier genes may be implicated. We assessed the prevalence of cholelithiasis and the effect of co-inherited Gilbert's syndrome genotype on its development in 261 thalassaemia major (TM) and 35 thalassaemia intermedia (TI) patients. Cholelithiasis was found in 20.3% of TM and in 57.1% of TI patients. Its incidence was higher (P < 0.05) in patients homozygous for the (TA7) motif in the promoter of the UGT1-A1 gene, the genotype associated with Gilbert's syndrome, which seems to be a risk factor for the development of gallstones in TM and TI patients.

Role of cholesterol synthesis and esterification in the growth of CEM and MOLT4 lymphoblastic cells.

CEM and MOLT4 are human T-cell lines isolated from patients with acute cell leukaemia. In culture they show important differences in cholesterol metabolism, CEM being less efficient at synthesizing cholesterol and having a lower activity of 3-hydroxy-3-methylglutaryl-CoA (HMGCoA) reductase. To investigate further the relationship between regulation of intracellular cholesterol metabolism at various steps and rate of cell growth, cholesterol synthesis, esterification and efflux were evaluated in CEM and MOLT4 cells at different times during exponential and stationary growth in vitro. It was shown that, although CEM cells have a lower rate of cholesterol synthesis, they grow at a faster rate than MOLT4 cells. However, CEM cells exhibit an increased capacity to esterify cholesterol associated with a decreased efflux of newly synthesized cholesterol into the medium. These results provide evidence for an association between the capability to synthesize and retain cell cholesterol esters and the growth rate potential.