Synthesis and evaluation of chromenyl barbiturates and thiobarbiturates as potential antitubercular agents

A novel series of barbiturate and thiobarbiturate analogs of 2-benzoyl-3-methyl-5-oxo-5H-furo[3,2-g]chromene-6-carbaldehydes (3a-g and 4a-d, respectively) and 6-methyl-4,8-dioxo-4,8-dihydropyrano[3,2-g]chromenes (7a-c), were synthesized and evaluated for their antitubercular activities against Mycobacterium tuberculosis H37RV, and cytotoxicity (CC₅₀) in the VERO cell MABA assay. The results indicate that the furanochromene series of compounds (3a-g and 4a-d) showed only weak to moderate antitubercular activity. However, the pyranochromene analog 7b showed good antitubercular activity (IC₉₀: 5.9 μg/mL) and cytotoxicity (CC₅₀: 14.27 μg/mL). The antitubercular activity of 7b was superior to the antituberculosis drug, pyrazinamide (PZA; IC₉₀: >20 μg/mL). Analog 7b was considered to be a lead compound for subsequent structural optimization.     

Inhibitory effects of Mannich bases of heterocyclic chalcones on NO production by activated RAW 264.7 macrophages and superoxide anion generation and elastase release by activated human neutrophils

Some chalcones exert potent anti-inflammatory activities. Mannich bases of heterocyclic chalcones inhibited nitric oxide (NO) production in lipopolysaccharide and interferon-γ stimulated RAW 264.7 macrophages. Also Formyl-Met-Leu-Phe and cytochalasin B induced superoxide anion generation (O2·-) and elastase release in human neutrophils. Mannich bases of heterocyclic chalcone analogs exhibited potent inhibitory effects on NO production with IC(50) values ranges between 10.5 and 0.018 μM, O2·- generation (IC(50) 39.87-0.68 μM) and elastase release (IC(50) 39.74-0.95 μM). Compound 29 (IC(50) 0.055 μM) and 34 (IC(50) 0.018 μM) were showed excellent inhibition on NO production. On the other hand, compounds 2 and 8 showed potent inhibition on O2·- generation and elastase release. Therefore, these four compounds may be new leads for development of anti-inflammatory activities. The structure-activity relationships are also discussed.     

Molecular docking studies of 1-(substituted phenyl)-3-(naphtha [1, 2-d] thiazol-2-yl) urea/thiourea derivatives with human adenosine A(2A) receptor

Computational assessment of the binding interactions of drugs is an important component of computer-aided drug design paradigms. In this perspective, a set of 30 1-(substituted phenyl)-3-(naphtha[1, 2-d] thiazol-2-yl) urea/thiourea derivatives showing antiparkinsonian activity were docked into inhibitor binding cavity of human adenosine A(2A) receptor (AA2AR) to understand their mode of binding interactions in silico. Lamarckian genetic algorithm methodology was employed for docking simulations using AutoDock 4.2 program. The results signify that the molecular docking approach is reliable and produces a good correlation coefficient (r(2) = 0.483) between docking score and antiparkinsonian activity (in terms of % reduction in catalepsy score). Potent antiparkinsonian agents carried methoxy group in the phenyl ring, exhibited both hydrophilic and lipophilic interactions with lower energy of binding at the AA(2A)R. These molecular docking analyses should, in our view, contribute for further development of selective AA(2A)R antagonists for the treatment of Parkinson's disease.     

Residues 334 and 338 in transmembrane segment 8 of human equilibrative nucleoside transporter 1 are important determinants of inhibitor sensitivity, protein folding, and catalytic turnover

Equilibrative nucleoside transporters (ENTs) are important for the metabolic salvage of nucleosides and the cellular uptake of antineoplastic and antiviral nucleoside analogs. Human equilibrative nucleoside transporter 1 (hENT1) is inhibited by nanomolar concentrations of structurally diverse compounds, including dipyridamole, dilazep, nitrobenzylmercaptopurine ribonucleoside (NBMPR), draflazine, and soluflazine. Random mutagenesis and screening by functional complementation for inhibitor-resistant mutants in yeast revealed mutations at Phe-334 and Asn-338. Both residues are predicted to lie in transmembrane segment 8 (TM 8), which contains residues that are highly conserved in the ENT family. F334Y displayed increased V(max) values that were attributed to increased rates of catalytic turnover, and N338Q and N338C displayed altered membrane distributions that appeared to be because of protein folding defects. Mutations of Phe-334 or Asn-338 impaired interactions with dilazep and dipyridamole, whereas mutations of Asn-338 impaired interactions with draflazine and soluflazine. A helical wheel projection of TM 8 predicted that Phe-334 and Asn-338 lie in close proximity to other highly conserved and/or hydrophilic residues, suggesting that they form part of a structurally important region that influences interactions with inhibitors, protein folding, and rates of conformational change during the transport cycle.     

Structural analysis and prediction of protein mutant stability using distance and torsion potentials: role of secondary structure and solvent accessibility

Platelet-activating factor receptor (PAFR) is a member of G-protein coupled receptor (GPCR) superfamily. Understanding the regulation mechanisms of PAFR by its agonists and antagonists at the atomic level is essential for designing PAFR antagonists as drug candidates for treating PAF-mediated diseases. In this study, a 3D model of PAFR was constructed by a hierarchical approach integrating homology modeling, molecular docking and molecular dynamics (MD) simulations. Based on the 3D model, regulation mechanisms of PAFR by agonists and antagonists were investigated via three 8-ns MD simulations on the systems of apo-PAFR, PAFR-PAF and PAFR-GB. The simulations revealed that binding of PAF to PAFR triggers the straightening process of the kinked helix VI, leading to its activated state. In contrast, binding of GB to PAFR locks PAFR in its inactive state.     

Statin initiation and treatment non-adherence following a first acute myocardial infarction in patients with inflammatory rheumatic disease versus the general population

Introduction

To compare statin initiation and treatment non-adherence following a first acute myocardial infarction (MI) in patients with inflammatory rheumatic disease (IRD) and the general population.

Methods

We conducted a retrospective cohort study using a population-based linked database. Cases of first MI from July 2001 to June 2009 were identified based on International Classification of Diseases (ICD-10-AM) codes. Statin initiation and adherence was identified based on pharmaceutical claims records. Logistic regression was used to assess the odds of statin initiation by IRD status. Non-adherence was assessed as the time to first treatment gap using a Cox proportional hazards model.

Results

There were 18,518 individuals with an index MI over the time period surviving longer than 30 days, of whom 415 (2.2%) were IRD patients. The adjusted odds of receiving a statin by IRD status was significantly lower (OR =0.69, 95% CI: 0.55 to 0.86) compared to the general population. No association between IRD status and statin non-adherence was identified (hazard ratio (HR) =1.12, 95% CI: 0.82 to 1.52).

Conclusions

Statin initiation was significantly lower for people with IRD conditions compared to the general population. Once initiated on statins, the proportion of IRD patients who adhered to treatment was similar to the general population. Given the burden of cardiovascular disease and excess mortality in IRD patients, encouraging the use of evidence-based therapies is critical for ensuring the best outcomes in this high risk group.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0443-y) contains supplementary material, which is available to authorized users.     

Overexpressed galectin-3 in pancreatic cancer induces cell proliferation and invasion by binding ras and activating ras signaling

Pancreatic cancer (PDAC) is a lethal disease with a five-year survival of 3-5%. Mutations in K-Ras are found in nearly all cases, but K-Ras mutations alone are not sufficient for the development of PDAC. Additional factors contribute to activation of Ras signaling and lead to tumor formation. Galectin-3 (Gal-3), a multifunctional β-galactoside-binding protein, is highly expressed in PDAC. We therefore investigated the functional role of Gal-3 in pancreatic cancer progression and its relationship to Ras signaling. Expression of Gal-3 was determined by immunohistochemistry, Q-PCR and immunoblot. Functional studies were performed using pancreatic cell lines genetically engineered to express high or low levels of Gal-3. Ras activity was examined by Raf pull-down assays. Co-immunoprecipitation and immunofluorescence were used to assess protein-protein interactions. In this study, we demonstrate that Gal-3 was highly up-regulated in human tumors and in a mutant K-Ras mouse model of PDAC. Down-regulation of Gal-3 by lentivirus shRNA decreased PDAC cell proliferation and invasion in vitro and reduced tumor volume and size in an orthotopic mouse model. Gal-3 bound Ras and maintained Ras activity; down-regulation of Gal-3 decreased Ras activity as well as Ras down-stream signaling including phosphorylation of ERK and AKT and Ral A activity. Transfection of Gal-3 cDNA into PDAC cells with low-level Gal-3 augmented Ras activity and its down-stream signaling. These results suggest that Gal-3 contributes to pancreatic cancer progression, in part, by binding Ras and activating Ras signaling. Gal-3 may therefore be a potential novel target for this deadly disease.     

Mosaic down syndrome with a marker: molecular cytogenetic characterization of the marker chromosome

Down syndrome is a complex disorder characterized by well defined and distinctive phenotypic features. Approximately 2-3% of all live-born Down individuals are mosaics. Here we report a boy with suspected Down syndrome showing mosaicism for two different cell lines where one cell line is unexpected. The cytogenetic analysis by G-banding revealed a karyotype of 47 XY+21 [20]/46,X+marker [30]. Further, molecular cytogenetic analysis with spectral karyotyping identified the marker as a derivative of Y chromosome. The delineation of Y chromosomal DNA was done by quantitative real-time PCR and aneuploidy detection by quantitative fluorescence PCR. The Y-short tandem repeats typing was performed to estimate the variation in quantity as well as to find out the extent of deletion on Y chromosome using STR markers. Fluorescence in situ hybridization using Y centromeric probe was also performed to confirm the origin of the Y marker. Further fine mapping of the marker was carried out with three bacterial artificial chromosome clones RP11-20H21, RP11-375P13, RP11-71M14, which defined the hypothetical position of the deletion. In our study we defined the extent of deletion of the marker chromosome and also discussed it in relation with mosaicism. This is the first report of mosaic Down syndrome combined with a second de novo mosaic marker derived from the Y chromosome.