Synthesis,DNA/BSA binding studies and in vitro biological assay of nickel(II) complexes incorporating tridentate aroylhydrazone and triphenylphosphine ligands

Abstract

Two new nickel (II) triphenylphosphine complexes derived from tridentate aroylhydrazone ligands [H₂L¹ = 2-hydroxy-3-methoxybenzylidene)benzohydrazone and H₂L² = N′-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazone] and triphenylphosphine were prepared and their molecular structures were determined by single crystal X-ray diffraction analysis. Both nickel(II) complexes showed slightly distorted square planar geometry with one tridentate aroylhydrazone ligand coordinated through ONO donor atoms and one triphenylphosphine ligand coordinated to the nickel center through the phosphorus atom. DNA interaction studies indicated that both complexes possessed higher affinity to herring sperm DNA (HS-DNA) than the corresponding free aroylhydrazone ligand. Molecular docking investigations showed that both complexes could bind to DNA through intercalation of the phenyl rings between adjacent base pairs in the double helix. Meanwhile, bovine serum albumin (BSA) binding studies revealed the complexes could effectively interact with BSA and change the secondary structure of BSA. Further pharmacological evaluations of the synthesized complexes by in vitro antioxidant assays demonstrated high antioxidant activity against NO· and O₂˙^? radicals. The anticancer activity of each complex was assessed through in vitro cytotoxicity assays (CCK-8 kit) toward A549 and MCF-7 cancer cell and normal L-02 cell lines. Significantly, the Ni(II) complex derived from H₂L¹ ligand was found to be more effective cytotoxic toward MCF-7cancerous cell with the IC₅₀ value equaled 9.7?μM, which showed potent cytotoxic activity over standard drug cisplatin.

Abbreviations A549 human lung carcinoma cell

BSA bovine serum albumin

CCK-8 Cell Counting Kit-8

DFT density functional theory

DNA deoxyribonucleic acid

DPPH˙ 2,2-diphenyl-1-picrylhydrazyl

H₂L¹ 2-hydroxy-3-methoxybenzylidene)benzohydrazone N′-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazone

H₂L² N′-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazone

HOMO highest occupied molecular orbital

IC₅₀ the 50% activity

L-02 human normal liver cell

LOMO lowest unoccupied molecular orbital (LUMO)

MCF-7 human breast carcinoma cell

NO˙ nitric oxide

O₂˙^? superoxide anion

SOD superoxide dismutase

Communicated by Ramaswamy H. Sarma     

In vitro cytotoxicity and DNA/HSA interaction study of triamterene using molecular modelling and multi-spectroscopic methods

The anticancer activity of triamterene on HCT116 and CT26 colon cancer cells lines was investigated. Furthermore, the mechanism of interaction between triamterene and calf thymus DNA (ct-DNA) and also human serum albumin (HSA) was conducted using spectroscopic and molecular docking techniques. In vitro cytotoxicity of triamterene against HCT116 and CT26 cells showed promising anticancer effects with IC50 values of 31.30 and 24.45 μM, respectively. Competitive studies of the triamterene with NR (neutral red) and MB (methylene blue) as intercalator probes showed that triamterene can be replaced by these probes. The viscosity data also confirmed that triamterene binds to calf–thymus DNA through intercalation binding mode. Binding properties of triamterene with HSA in the presence of warfarin and ibuprofen showed that triamterene competes with warfarin for the site I of human serum albumin (HSA). In addition, the binding modes of triamterene with DNA and HSA were verified by molecular docking technique. Abbreviations ct-DNA calf thymus DNA

CV cyclic voltammetry

DNA deoxyribonucleic acid

DPV differential pulse voltammetry

FBS fetal bovine serum

HSA human serum albumin

NR neutral red

MB methylene blue

MTT 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazoliumbromide

Communicated by Ramaswamy H. Sarma     

Seed-specific increased expression of 2S albumin promoter of sesame qualifies it as a useful genetic tool for fatty acid metabolic engineering and related transgenic intervention in sesame and other oil seed crops

The sesame 2S albumin (2Salb) promoter was evaluated for its capacity to express the reporter gusA gene encoding β-glucuronidase in transgenic tobacco seeds relative to the soybean fad3C gene promoter element. Results revealed increased expression of gusA gene in tobacco seed tissue when driven by sesame 2S albumin promoter. Prediction based deletion analysis of both the promoter elements confirmed the necessary cis-acting regulatory elements as well as the minimal promoter element for optimal expression in each case. The results also revealed that cis-regulatory elements might have been responsible for high level expression as well as spatio-temporal regulation of the sesame 2S albumin promoter. Transgenic over-expression of a fatty acid desaturase (fad3C) gene of soybean driven by 2S albumin promoter resulted in seed-specific enhanced level of α-linolenic acid in sesame. The present study, for the first time helped to identify that the sesame 2S albumin promoter is a promising endogenous genetic element in genetic engineering approaches requiring spatio-temporal regulation of gene(s) of interest in sesame and can also be useful as a heterologous genetic element in other important oil seed crop plants in general for which seed oil is the harvested product. The study also established the feasibility of fatty acid metabolic engineering strategy undertaken to improve quality of edible seed oil in sesame using the 2S albumin promoter as regulatory element.     

Determination of equilibria constants of arginine:glycine amidinotransferase (AGAT)-catalyzed reactions using concentrations of circulating amino acids

Arginine:glycine amidinotransferase (AGAT) catalyzes mainly two reactions that generate 1) L-homoarginine (hArg) from L-arginine and L-lysine (K_harg) and 2) guanidinoacetate (GAA) and L-ornithine from L-arginine and glycine (K_gaa). Previously, we found that pharmacological treatment of Becker muscular dystrophy (BMD) patients with metformin or L-citrulline resulted in antidromic effects on serum hArg and GAA concentrations, seemingly acting as an inhibitor and effector of AGAT activity, respectively. Here, we used data of this study as a model to determine K_harg and K_gaa values by using the concentrations of the participating amino acids measured in serum samples of the BMD patients. The study aimed to prove the general utility of this approach to investigate effects of amino acids and drugs on AGAT-catalyzed reactions in vivo in humans.

     

Metformin restores the correlation between serum-oxidized LDL and leptin levels in type 2 diabetic patients

Abstract

Introduction

Leptin has lipid peroxidation properties in healthy individuals. Here we aimed to study the correlation between serum-oxidized low-density lipoprotein (ox-LDL) and leptin levels in patients with type 2 diabetes. We also studied the effect of metformin therapy on the correlation between serum ox-LDL and leptin levels in patients with newly diagnosed diabetes.

Methods

We performed a cross-sectional study on two groups of patients with type 2 diabetes stratified according to (1) patients with newly diagnosed diabetes and (2) patients with long-standing diabetes plus healthy controls. Patients with newly diagnosed diabetes were followed for 3 months after the initiation of metformin therapy.

Results

Patients with type 2 diabetes had a higher serum ox-LDL, ox-LDL/LDL ratio, waist circumference, fasting blood sugars (FBSs), hemoglobin A1C (HbA1C), triglyceride, homeostatic model assessment of insulin resistance (HOMA-IR) and a lower serum leptin levels than controls. Serum ox-LDL, ox-LDL/LDL ratio (0.08 (0.08–0.12) vs. 0.06 (0.05–0.08), P < 0.001) and HOMA-IR (3.26 ± 0.23 vs. 2.93 ± 0.32; P < 0.01) were decreased when serum leptin levels (15.9 ± 1.6 vs. 21.4 ± 2.5, P < 0.01) were increased after 3 months of metformin therapy. This remained significant after multiple adjustments for age, body mass index, FBS, HbA1c, and HOMA-IR. Leptin was significantly correlated with ox-LDL/LDL ratio in controls (r = 0.78, P < 0.01), and in patients with newly diagnosed diabetes (r = 0.4, P < 0.05), after metformin therapy. There were not any correlation between leptin and ox-LDL/LDL ratio in patients with long-standing diabetes and patients with newly diagnosed diabetes before treatment.

Discussion

Metformin restores the positive correlation between serum ox-LDL and leptin levels in patients with type 2 diabetes.     

Lysophosphatidic acid and apolipoprotein A1 predict increased risk of developing World Trade Center-lung injury: a nested case-control study

Abstract

Rationale: Metabolic syndrome, inflammatory and vascular injury markers measured in serum after World Trade Center (WTC) exposures predict abnormal FEV₁. We hypothesized that elevated LPA levels predict FEV₁?<?LLN.

Methods: Nested case-control study of WTC-exposed firefighters. Cases had FEV₁?<?LLN. Controls derived from the baseline cohort. Demographics, pulmonary function, serum lipids, LPA and ApoA1 were measured.

Results: LPA and ApoA1 levels were higher in cases than controls and predictive of case status. LPA increased the odds by 13% while ApoA1 increased the odds by 29% of an FEV₁?<?LLN in a multivariable model.

Conclusions: Elevated LPA and ApoA1 are predictive of a significantly increased risk of developing an FEV₁?<?LLN.     

Clinical value of serum trophoblast cell surface protein 2 (TROP2) antibody in non-small-cell lung cancer patients

Objective: This study was to explore the clinical role of serum trophoblast cell surface protein 2 (TROP2) antibody in patients with non-small-cell lung cancer (NSCLC).

Materials and methods: We collected serum specimens from 117 NSCLC patients, 40 benign lung disease patients, and 60 healthy controls. TROP2 antibody concentrations were measured using enzyme-linked immunosorbent assay.

Results: Serum TROP2 antibody levels were higher in the NSCLC group compared to the control group (p?Conclusion: Measurement of TROP2 antibody might have diagnostic value for patients with NSCLC.     

Chemiluminescence Assays of Cu2Zn2 Superoxide Dismutase Mimicking Cu-Complexes

The aqueous decay of K₃CrO₈ was used to compare the reactivity of Cu₂Zn₂ superoxide dismutase and two active centre analogues where the first shell atoms around the copper are four unsaturated nitrogens. Unlike the acetate or biuret type Cu(II) chelates these di-Schiff-base complexes had an identical reactivity compared to that of the intact enzyme. Nanomolar concentrations of copper coordinated in these complexes were sufficient to inhibit the K₃CrO₈ induced chemiluminescence by 50%.

Furthermore, a lucigenin amplified chemiluminescence assay based on isolated polymorph nuclear leucocytes in the absence and presence of whole, unseparated blood was developed and successfully employed. CuPu(Im), and CuPu(Py), equivalent to 0.5 and 0.8 SOD units. only, were required to inhibit the photon emission by 50% in the absence of bovine serum albumin. Even in the presence of 600 μM albumin mimicking the competitive copper chelation in biological fluids Cu-Pu(Py)₂ and CuPu(lm)₂ remained active, whereas the carboxylate-and biuret type chelates Cu(Sal)₂ and Cu(Ser)₂ reacted like CuSO₄ The same reactivity of these low M, SOD mimics was seen in human blood.     

The relationship of the phase and amplitude of the annual cycle of CO2 to phenological events

Background: A key current issue in studies of global CO₂ is the cause of the recent pronounced changes in the timing (phase) and amplitude of its annual cycle.

Aim: To use a sensitivity analysis in order to identify the most influential parameters in a new four-box diffusion model of global CO₂ transport.

Methods: A new diffusion model of global atmospheric transport is developed, implemented by optimisation and used to assess the effects of oceanic, terrestrial and anthropogenic CO₂ fluxes on the annual CO₂ cycle. As the terrestrial phenology of living organisms in the temperate zones is identified as the central process of concern an improved phenological model for the temperate zones is proposed and used in up-scaling from plant to planet.

Results: The diffusion model is found to be able to mimic many of the features observed by the GLOBALVIEW-CO₂ network, including the global trend, latitudinal gradient, and annual waveform.

Conclusions: It is concluded that, out of five rival hypotheses considered at the outset, the springtime phenology of terrestrial biomes is the dominant controller of recent changes to the annual CO₂ cycle.     

Decreased paraoxonase 2 enzymatic activity in monocyte/macrophages cells. A comparative in vivo and in vitro study for diabetes

Aim: To investigate peripheral blood monocytes/macrophages (Mo/M?) paraoxonase 2 (PON2) in diabetes and the factors modulating its activity.

Methods: One hundred and eighteen patients with newly diagnosed uncomplicated type 2 diabetes mellitus were compared regarding clinical, biochemical and oxidative stress parameters with 80 healthy subjects. The capacity of the peripheral blood mononuclear cells (PBMNC) to release pro-oxidants and to neutralise them was determined by measuring the respiratory burst (RB) and the intracellular antioxidant enzyme PON2. In vitro experiments were conducted on a differentiated monocytes cell line (dU937) that was exposed to serum deprivation followed by addition of isolated lipoproteins (VLDL or LDL).

Results: Paraoxonase 2 activity in Mo/M? was significantly lower in type 2 diabetes patients (0.042?±?0.044 vs 0.165?±?0.133U lactonase activity/mg protein in controls, p?1c) and insulin resistance (HOMA-IR). In multivariate regression models, 15–34% of the PON2 variance was explained by diabetes. The in vitro addition of VLDL normalised the RB of serum deprived dU937 cells, S? (to 82?±?18% of the cells incubated with serum, S+) and PON2 activity (from 0.524?±?0.061 in S???to 0.298?±?0.048?U/mg protein). In contrast, when LDL was added, the RB remained lower (61?±?12% of S+, p?=?.03) and PON2 higher (0.580?±?0.030?U/mg protein, p?=?.003).

Conclusions: The decrease in monocyte/macrophage PON2 enzymatic activity observed in type 2 diabetes cannot be totally explained by abdominal obesity and insulin resistance. The underlying molecular mechanisms need to be identified.     

Comparative study of the bindings between 3-phenyl-1H-indazole and five proteins by isothermal titration calorimetry,spectroscopy and docking methods

Abstract

In this study, the interaction between 3-phenyl-1H-indazole (1a) and the fat mass and obesity-associated (FTO) protein was confirmed by isothermal titration calorimetry (ITC). The structure feature of 1a was different from our previously reported FTO inhibitors (radicicol, N-CDPCB and CHTB); the Cl and diol group in structure motif is critical for inhibitors to bind to FTO. In order to test whether there is specificity for the interaction between FTO and 1a, the interactions between 1a and four important proteins (human serum albumin (HSA), pepsin, catalase and trypsin) were investigated by ITC, spectroscopy and molecular docking methods. ITC results showed spontaneous exothermic reactions occurring between 1a and the proteins except trypsin under investigated conditions. The order of the binding affinity of 3-phenyl-1H-indazole is catalase?>?HSA?>?FTO?>?pepsin. Comparison between ITC and spectral results was made. This work will provide the basis for the design of novel inhibitors for FTO. Abbreviations CAT catalase

DMSO dimethyl sulfoxide

FTO fat mass and obesity-associated protein

HSA human serum albumin

Pep pepsin

Try trypsin

Communicated by Ramaswamy H. Sarma     

FORMATION OF 2′-DEOXY-2-NITROADENOSINES BY REACTION OF 2′-DEOXYADENOSINES WITH COPPER(II) NITRATE/ACETIC ANHYDRIDE

ABSTRACT

Nitration of 9-substituted [ethyl, (Ac)₂-2′-deoxyribosyl, (Ac)₃-ribosyl] N ⁶-acetyladenine derivatives with Cu(NO₃)₂·3H₂O/Ac₂O was examined. Nitration proceeded at the 2-position, although the yield was low. Removal of the acetyl groups gave 2′-deoxy-2-nitroadenosine derivatives.     

Synthesis and Biological Activity of 5-Azacytosine Nucleosides Derived from 4-Thio-2-Deoxy-L-threo-Pentofuranose and 4-Thio-2-Deoxy-D-erythro-Pentofuranose

Abstract

1-O-Acetyl-2-deoxy-3,5-di-O-toluoyl-4-thio-_d-erythro-pentofuranose and 2-deoxy-1,3,5-tri-O-acetyl-4-thio-_l-threo-pentofuranose were coupled with 5-azacytosine to obtain α and β anomers of nucleosides.     

Efficient Synthesis of 2′-Bromo-2′-Deoxy-3′,5′-O-TPDS-pyrimidine Nucleosides by Boron Trifluoride Catalyzed Reaction of O2,2′-Anhydro-(1-β-D-Arabinofuran0Syl)pyrimidine Nucleosides with Lithium Bromide

Abstract

Efficient syntheses of 2′-bromo-2′-deoxy-3′,5′-O-TPDS-uridine (5a) and 1-(2-bromo-3,5-O-TPDS-β-D-ribofuranosyl)thymine (5b) from uridine and 1-(β-D-ribofuranosyl)thymine are described, respectively. The key step is a treatment of 3′,5′-O-TPDS-O²,2′-anhydro-1-(β-D-ardbinofuranosyl)uracil (4a) and -thymine (4b) with LiBr in the presence of BF₃-OEt₂ in 1,4-dioxane at 60°C to give 5a and 5b in 98%, and 96% yield, respectively.

     

F2-Isoprostanes,tocopherols and normal pregnancy

This study investigates oxidative stress and antioxidants in normal human pregnancy and post-partum period. Thirty-seven healthy women with normal pregnancies were included. Both urinary and serum samples were collected throughout the pregnancy and post-partum period. Oxidative stress was estimated by measuring the reliable in vivo marker, namely 8-iso-prostaglandin F_2α (8-iso-PGF_2α, an F₂-isoprostane) and antioxidant status was evaluated by measuring α- and γ-tocopherol in serum samples. Pregnancy was associated with successively increased levels of 8-iso-PGF_2α with advancing gestational age. The median post-partum value corresponded to the values observed in early gestation and a significant decrease was observed from late pregnancy to the post-partum period. Lipid-adjusted α- and γ-tocopherol levels decreased with advancing gestational age. This longitudinal study suggests that mild oxidative stress is involved in normal human pregnancy.     

Dynamic changes in serum angiopoietin-1, angiopoietin-2, and angiopoietin-2/angiopoietin-1 ratio in acute myocardial infarction patients treated with primary percutaneous coronary intervention

Context: Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) play divergent roles in myocardial ischemia and reperfusion injury.

Objective: To investigate serum Ang-1 and Ang-2 levels in ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PCI).

Methods: Serum Ang-1 and Ang-2 were measured in 85 STEMI patients in the first week after PCI.

Results: Ang-1, Ang-2 and Ang-2/Ang-1 ratio (Ang-2/1) were all increased at admission, and had dynamic changes after PCI. Ang-2 and Ang-2/1 at admission and 2 h after PCI were positively correlated with peak cardiac troponin T levels.

Conclusion: The extent of myocardial damage may be linked to circulating Ang-2 and Ang-2/1.     

Calcitriol attenuates TLR2/IL-33 signaling pathway to repress Th9 cell differentiation and potentially limits the pathophysiology of rheumatoid arthritis

There is limited information regarding the TLR2 signaling pathway involved in Th9 cell differentiation. The role of calcitriol in regulating TLR2-mediated Th9 cell development is unknown. Thus, we aimed to unravel the TLR2 signaling pathway in Th9 cells and its regulation by calcitriol. We have used n?=?5–6 animals for each murine experiment. Human studies involved five healthy volunteers. Moreover, ten healthy individuals and ten RA patients were included in the study. Murine and human Th9 cells were treated with Calcitriol (100 nM) and Pam₃CSK₄ (2 µg/mL). The number of IL-9+ve cells was determined by flow cytometry. Real-time PCR was used to assess the gene expression. Serum 25(OH)D₃ levels were determined by HPLC. We observed that TLR2 signals via IL-33/ST2 in Th9 cells. Increased TLR2 expression associated with increased IL9 expression and augmented disease severity in RA patients. Calcitriol attenuated TLR2 signaling in murine and human Th9 cells. Low serum vitamin D3 level negatively associated with increased IL-9 and TLR2 expression and disease severity in RA patients. Our data suggest a potential role of calcitriol to ameliorate the disease severity of RA patients.

     

UPTAKE OF LIPOSOMES WHICH INCORPORATE A GLYCOPEPTIDE FRACTION OF ASIALOFETUIN BY HepG2 CELLS

We examined the interaction between liposomes which incorporate a fraction triantennary glycopeptide (AF₂) of asialofetuin and human hepatoma cells (HepG₂) in vitro. HepG₂ cells are known to express the asialoglycoprotein receptor.

For liposome preparation AF₂ was cleaved from asialofetuin, purified and conjugated with different length (C₁₂,C₁₆ and C₁₈) fatty acids (FA). The conjugates were subsequently incorporated into pre-formed sonicated liposomes using a mild cholate incubation method. Interactions between AF₂/FA-liposomes as well as control-liposomes (with no ligand) and cells (in the presence of serum) were measured at different lipid doses after incubating HepG₂ cells with liposomes at 4°C and 37°C, in the absence and presence of galactose, and also evaluated by fluorescence microscopy. More extensive studies were performed with the AF₂/C₁₈-liposomes which were previously found to incorporate higher amounts of ligand and be the most stable of the formulations prepared.

Results from both, morphological and quantitative studies, demonstrate that AF₂/C₁₆ and especially AF₂/C₁₈-liposomes are bound and taken up by the cells by a galactose specific mechanism. The AF₂/C₁₂-liposomes-which were previously found to incorporate low amounts of ligand in a non-stable way- were taken up by the cells in amounts similar to those of the control liposomes (without ligand) while this uptake was not reduced by galactose and therefore possibly non-specific. The intracellular localization of AF₂/C₁₈-liposomes was further evidenced by intracellular acidification using NH₄Cl. These conclusions, justify the importance of further in vivo studies in order to demonstrate the capability of the proposed system to target hepatocytes.     

O2 versus N2O respiration in a continuous microbial enrichment

Despite its ecological importance, essential aspects of microbial N₂O reduction—such as the effect of O₂ availability on the N₂O sink capacity of a community—remain unclear. We studied N₂O vs. aerobic respiration in a chemostat culture to explore (i) the extent to which simultaneous respiration of N₂O and O₂ can occur, (ii) the mechanism governing the competition for N₂O and O₂, and (iii) how the N₂O-reducing capacity of a community is affected by dynamic oxic/anoxic shifts such as those that may occur during nitrogen removal in wastewater treatment systems. Despite its prolonged growth and enrichment with N₂O as the sole electron acceptor, the culture readily switched to aerobic respiration upon exposure to O₂. When supplied simultaneously, N₂O reduction to N₂ was only detected when the O₂ concentration was limiting the respiration rate. The biomass yields per electron accepted during growth on N₂O are in agreement with our current knowledge of electron transport chain biochemistry in model denitrifiers like Paracoccus denitrificans. The culture’s affinity constant (K_S) for O₂ was found to be two orders of magnitude lower than the value for N₂O, explaining the preferential use of O₂ over N₂O under most environmentally relevant conditions.