Aerobic Cytotoxicity of Aromatic N-Oxides: The Role of NAD(P)H:Quinone Oxidoreductase (NQO1)

Derivatives of tirapazamine and other heteroaromatic N-oxides (ArN→O) exhibit tumoricidal, antibacterial, and antiprotozoal activities, which are typically attributed to bioreductive activation and free radical generation. In this work, we aimed to clarify the role of NAD(P)H:quinone oxidoreductase (NQO1) in ArN→O aerobic cytotoxicity. We synthesized 9 representatives of ArN→O with uncharacterized redox properties and examined their single-electron reduction by rat NADPH:cytochrome P-450 reductase (P-450R) and Plasmodium falciparum ferredoxin:NADP⁺ oxidoreductase (PfFNR), and by rat NQO1. NQO1 catalyzed both redox cycling and the formation of stable reduction products of ArN→O. The reactivity of ArN→O in NQO1-catalyzed reactions did not correlate with the geometric average of their activity towards P-450R- and PfFNR, which was taken for the parameter of their redox cycling efficacy. The cytotoxicity of compounds in murine hepatoma MH22a cells was decreased by antioxidants and the inhibitor of NQO1, dicoumarol. The multiparameter regression analysis of the data of this and a previous study (DOI: 10.3390/ijms20184602) shows that the cytotoxicity of ArN→O (n = 18) in MH22a and human colon carcinoma HCT-116 cells increases with the geometric average of their reactivity towards P-450R and PfFNR, and with their reactivity towards NQO1. These data demonstrate that NQO1 is a potentially important target of action of heteroaromatic N-oxides.     

Guidelines for the Application of NAD(P)H Regenerating Glucose Dehydrogenase in Synthetic Processes

Glucose dehydrogenase (GDH) is frequently used for the reduction of NAD⁺ and NADP⁺ in bench‐ and industrial‐scale syntheses because the coenzyme regenerating system GDH is easy to apply, robust and relatively inexpensive. To optimize the application of this long known coenzyme regeneration system we investigated the commonly applied Bacillus GDH and characterized this enzyme by its kinetic features in the presence of substrates and products at pH 6.4 and 8.0. Three substrates/products were found to inhibit GDH considerably: (i) the reaction product glucono‐1,5‐lactone, (ii) the reduced coenzyme NAD(P)H and (iii) the oxidized coenzyme NAD(P)⁺. The inhibition of GDH under several process conditions was modeled using the determined kinetic constants. It was found that the GDH regeneration system is strongly inhibited by the usually applied conditions. This study provides the rate equation of the GDH reaction and simulations of this coenzyme regenerating system leading to an improved prediction and, thus, to a faster scale‐up and increased efficiency of NAD(P)H‐dependent synthetic processes.     

Self‐Immolative Bioluminogenic Quinone Luciferins for NAD(P)H Assays and Reducing Capacity‐Based Cell Viability Assays

Highly sensitive self‐cleavable trimethyl lock quinone‐luciferin substrates for diaphorase were designed and synthesized to measure NAD(P)H in biological samples and monitor viable cells via NAD(P)H‐dependent cellular oxidoreductase enzymes and their NAD(P)H cofactors.     

FLIM of NAD(P)H in Lymphatic Nodes Resolves T-Cell Immune Response to the Tumor

Assessment of T-cell response to the tumor is important for diagnosis of the disease and monitoring of therapeutic efficacy. For this, new non-destructive label-free methods are required. Fluorescence lifetime imaging (FLIM) of metabolic coenzymes is a promising innovative technology for the assessment of the functional status of cells. The purpose of this work was to test whether FLIM can resolve metabolic alterations that accompany T-cell reactivation to the tumors. The study was carried out on C57Bl/6 FoxP3-EGFP mice bearing B16F0 melanoma. Autofluorescence of the immune cells in fresh lymphatic nodes (LNs) was investigated. It was found that fluorescence lifetime parameters of nicotinamide adenine dinucleotide (phosphate) NAD(P)H are sensitive to tumor development. Effector T-cells in the LNs displayed higher contribution of free NADH, the form associated with glycolysis, in all tumors and the presence of protein-bound NADPH, associated with biosynthetic processes, in the tumors of large size. Flow cytometry showed that the changes in the NADH fraction of the effector T-cells correlated with their activation, while changes in NADPH correlated with cell proliferation. In conclusion, FLIM of NAD(P)H in fresh lymphoid tissue is a powerful tool for assessing the immune response to tumor development.     

Mechanisms of Enzyme-Catalyzed Reduction of Two Carcinogenic Nitro-Aromatics, 3-Nitrobenzanthrone and Aristolochic Acid I: Experimental and Theoretical Approaches

This review summarizes the results found in studies investigating the enzymatic activation of two genotoxic nitro-aromatics, an environmental pollutant and carcinogen 3-nitrobenzanthrone (3-NBA) and a natural plant nephrotoxin and carcinogen aristolochic acid I (AAI), to reactive species forming covalent DNA adducts. Experimental and theoretical approaches determined the reasons why human NAD(P)H:quinone oxidoreductase (NQO1) and cytochromes P450 (CYP) 1A1 and 1A2 have the potential to reductively activate both nitro-aromatics. The results also contributed to the elucidation of the molecular mechanisms of these reactions. The contribution of conjugation enzymes such as N,O-acetyltransferases (NATs) and sulfotransferases (SULTs) to the activation of 3-NBA and AAI was also examined. The results indicated differences in the abilities of 3-NBA and AAI metabolites to be further activated by these conjugation enzymes. The formation of DNA adducts generated by both carcinogens during their reductive activation by the NOQ1 and CYP1A1/2 enzymes was investigated with pure enzymes, enzymes present in subcellular cytosolic and microsomal fractions, selective inhibitors, and animal models (including knock-out and humanized animals). For the theoretical approaches, flexible in silico docking methods as well as ab initio calculations were employed. The results summarized in this review demonstrate that a combination of experimental and theoretical approaches is a useful tool to study the enzyme-mediated reaction mechanisms of 3-NBA and AAI reduction.     

Modeling of Anopheles minimus Mosquito NADPH-Cytochrome P450 Oxidoreductase (CYPOR) and Mutagenesis Analysis

Malaria is one of the most dangerous mosquito-borne diseases in many tropical countries, including Thailand. Studies in a deltamethrin resistant strain of Anopheles minimus mosquito, suggest cytochrome P450 enzymes contribute to the detoxification of pyrethroid insecticides. Purified A. minimus CYPOR enzyme (AnCYPOR), which is the redox partner of cytochrome P450s, loses flavin-adenosine di-nucleotide (FAD) and FLAVIN mono-nucleotide (FMN) cofactors that affect its enzyme activity. Replacement of leucine residues at positions 86 and 219 with phenylalanines in FMN binding domain increases FMN binding, enzyme stability, and cytochrome c reduction activity. Membrane-Bound L86F/L219F-AnCYPOR increases A. minimus P450-mediated pyrethroid metabolism in vitro. In this study, we constructed a comparative model structure of AnCYPOR using a rat CYPOR structure as a template. Overall model structure is similar to rat CYPOR, with some prominent differences. Based on primary sequence and structural analysis of rat and A. minimus CYPOR, C427R, W678A, and W678H mutations were generated together with L86F/L219F resulting in three soluble Δ55 triple mutants. The C427R triple AnCYPOR mutant retained a higher amount of FAD binding and increased cytochrome c reduction activity compared to wild-type and L86F/L219F-Δ55AnCYPOR double mutant. However W678A and W678H mutations did not increase FAD and NAD(P)H bindings. The L86F/L219F double and C427R triple membrane-bound AnCYPOR mutants supported benzyloxyresorufin O-deakylation (BROD) mediated by mosquito CYP6AA3 with a two-to three-fold increase in efficiency over wild-type AnCYPOR. The use of rat CYPOR in place of AnCYPOR most efficiently supported CYP6AA3-mediated BROD compared to all AnCYPORs.     

Royal Jelly Protects against Epidermal Stress through Upregulation of the NQO1 Expression

Royal jelly (RJ) is secreted by honeybees and has been used as an apitherapy to obtain healthy skin since ancient times. However, the mechanism of the protective effects of RJ against skin aging and skin diseases caused by skin stress and its components have not been clarified. In this study, we attempted to understand the effect of RJ on epidermal function and observed that NAD(P)H quinone dehydrogenase 1 (NQO1) is significantly induced by RJ in keratinocytes. The expression of NQO1 was also increased in the 3D epidermal skin model. NQO1 is involved in antioxidation and detoxification metabolism, and we found that RJ protects against the epidermal stress caused by UVB and menadione through the upregulation of NQO1. We identified 10-hydroxy-2-decenoic acid (10H2DA), a major fatty acid in RJ, as an active compound in this reaction as it induced the expression of NQO1 and protected the skin against oxidative stress. We demonstrated that the protective effect of RJ against epidermal stress is mediated through the upregulation of NQO1 by 10H2DA.     

P450 BM3 Monooxygenase as an Efficient NAD(P)H‐Oxidase for Regeneration of Nicotinamide Cofactors in ADH‐Catalysed Preparative Scale Biotransformations

Enzymatic oxidations of primary and secondary alcohols catalysed by nicotinamide dependent alcohol dehydrogenases on the preparative scale require cofactor regeneration systems. Of critical value from an economic and ecological perspective is the application of NAD(P)H‐oxidases, which utilise molecular oxygen as a cost‐effective, atom‐efficient and environmentally benign oxidant to regenerate the cofactor NAD(P)⁺. Herein, the P450 BM3 monooxygenase from Bacillus megaterium is presented as an NAD(P)H‐oxidase for the successful regeneration of both NADP⁺ and NAD⁺ on the preparative scale. This enzyme was exemplarily applied for ADH‐catalysed oxidative kinetic resolutions of racemic secondary alcohols and the desymmetrisation of a meso‐diol leading to enantiomerically enriched secondary alcohols in both cases. Furthermore, the ADH‐catalysed oxidation of a primary alcohol targeting the corresponding aldehyde was performed. The obtained results significantly broaden the scope of feasible oxidative biotransformations, thereby increasing the number of synthetic reactions complying with key challenges of a modern and sustainable chemistry such as mild reaction conditions, environmentally benign solvents, and biodegradable non‐toxic catalysts.

     

NAD(P)H:Quinone Oxidoreductase 1 (NQO1) P187S Polymorphism and Prostate Cancer Risk in Caucasians

NAD(P)H:quinone oxidoreductase 1 (NQO1) catalyses the reduction of quinoid compounds to hydroquinones, preventing the generation of free radicals and reactive oxygen. A “C” to “T” transversion at position 609 of NQO1, leading to a nonsynonymous amino acid change (Pro187Ser, P187S), results in an altered enzyme activity. No NQO1 protein activity was detected in NQO1 ⁶⁰⁹TT genotype, and low to intermediate activity was detected in NQO1 ⁶⁰⁹CT genotype compared with ⁶⁰⁹CC genotype. Thus, this polymorphism may result in altered cancer predisposition. For prostate cancer, only sparse data are available. We therefore analyzed the distribution of the NQO1 P187S SNP (single nucleotide polymorphism) in prostate cancer patients and a healthy control group. Allelic variants were determined using RFLP analysis. Overall, 232 patients without any malignancy and 119 consecutive prostate cancer patients were investigated. The genotype distribution in our cohorts followed the Hardy–Weinberg equilibrium in cases and controls. The distribution of the NQO1 codon 187 SNP did not differ significantly between prostate cancer patients and the control group (p = 0.242). There was also no association between the allelic variants and stage or Gleason score of the tumors. The NQO1 P187S SNP was not significantly associated with an increased prostate cancer risk in our cohorts. The SNP has also no influence on histopathological characteristics of the tumors. A combined analysis of all available data from published European studies also showed no significant differences in the genotype distribution between controls and prostate cancer patients. Our data suggest a minor role of the NQO1 nucleotide 609 polymorphism in prostate carcinogenesis.     

1-(2-氯苯基)-5(4H)-四唑啉酮的合成研究

1 (2 氯苯基 ) 5 (4H) 四唑啉酮 (Ⅰ)可由 2 氯硝基苯经三步合成反应制得。首先 ,2 氯硝基苯经铁粉还原得 2 氯苯胺 (Ⅱ) ,Ⅱ与碳酸二 (三氯甲基 )酯反应得 2 氯苯基异氰酸酯 (Ⅲ ) ,Ⅲ在DMF溶剂中 ,无水三氯化铝催化下与叠氮钠缩合得Ⅰ。三步收率分别为 90 %、80 %、90 % ,总收率为 6 5 %(以邻氯硝基苯计 ) ,产品质量分数达 95 %。     

4-氯-1-甲基-3-硝基-2(1H)-喹啉酮的合成

以N-甲基苯胺为起始原料,经过环合反应制得4-羟基-1-甲基-2(1H)-喹啉酮,再经硝化和氯代反应合成了目标化合物,该方法所用原料廉价易得,产物处理简单,适合工业化生产,总收率可达51.9%。     

H6P2M09W9O62/Zn(BDC)(Bipy)0.5复合材料催化合成3,4-二氢嘧啶-2(H)酮衍生物

采用水热法分别合成杂多酸H6P2Mo9W9O62及有机金属骨架Zn(BDC) (Bipy)0.5,使用浸渍法合成H6P2Mo9W9O62/Zn(BDC) (Bipy)05复合材料,用该复合材料催化醛、乙酰乙酸乙酯和尿素通过Biginelli反应,乙醇作溶剂,合成6种3,4-二氢嘧啶-2(H)酮衍生物.通过IR、1HNMR、13CNMR确定其结构,通过m.p.确定其纯度.实验结果表明:固定醛用量为0.04 mol,n(醛)∶n(乙酰乙酸乙酯)∶n(尿素)=1∶1.4∶1.5,2.0 wt％ H6P2Mo9W9O62/Zn(BDC)(Bipy)0.5,反应温度为105℃,反应时间为60 min时,产物收率为40.1％～91.5％.     

Poly(di-1H,1H,2H,2H-perfluoroalkylitaconate) films: surface organisation phenomena, surface energy determinations and force of adhesion measurements

The significance of the Liftshitz/van der Waals, Lewis-acid, and Lewis-base contributors to the total surface energy of an homologous series of poly(di-1H,1H,2H,2H-perfluoroalkylitaconate)s is discussed in terms of the molecular design features and surface organisation phenomena characterising these, comb-like, polymers. Comparison of the characteristics specific to films prepared from this class of materials with those of the previously-studied homologous series of poly(perfluoroalkylacrylate)s, poly(perfluoroalkylmethacrylate)s and poly(methylpropenoxyalkyl siloxane)s suggests that, of the molecular design requirements for low-surface-energy polymers, an increase in the packing density of pendent side-chains has little effect on the contributors to surface energy but an adverse effect on the roughness of the film.     

3,4-二氢-2(1H)喹啉酮衍生物的合成研究

对3,4-二氢-2(1H)喹啉酮衍生物1,2,3(R= NO2,NH2,OH;R= H,NO2,NH2)的合成进行了研究。以苯胺和3-氯丙酰氯为原料,制得N-苯基-3-氯丙酰胺,然后经环合得到3,4-二氢-2(1H)喹啉酮,再经由硝化、还原、重氮化水解合成了一系列3,4-二氢-2(1H)喹啉酮衍生物:6-硝基-3,4-二氢-2(1H)喹啉酮(1a),6,8-二硝基-3,4-二氢-2(1H)喹啉酮(1b),6-氨基-3,4-二氢-2(1H)喹啉酮(2a),6,8-二氨基-3,4-二氢-2(1H)喹啉酮(2b),6-氨基-8-硝基-3,4-二氢-2(1H)喹啉酮(2c),6-羟基-3,4-二氢-2(1H)喹啉酮(3a)和6-羟基-8-硝基-3,4-二氢-2(1H)喹啉酮(3b),其中化合物(2c)及(3b)为新化合物。单步产率均在86%以上,路线简单,操作简便,反应条件温和。采用MS,1HNMR对产品进行了定性及结构表征。     

Synthesis of some novel 2(1H)-quinazolinones and 2-thioxo analogues from newly synthesised 1-acyl-3-alkoxyphenylureas and thioureas

A convenient route for the synthesis of new 2(1H)-quinazolinones (IIc—h) and 2(1H)-quinazolinethiones (IIi—j) is discussed. It involves the cyclodehydration of 1-acyl-3-(alkoxyphenyl)ureas (Ic—h) and the corresponding thioureas (Ii—j) in polyphosphoric acid. Elucidation of structures of the isolated products have been proved in the light of their elemental analysis and spectroscopic data.     

1-羟基-1,2-苯碘酰-3(1H)-酮-1-氧化物(IBX)的合成及在他唑巴坦合成中的应用

首先以邻氨基苯甲酸为原料,与NaNO2和KI在酸性条件下反应制得邻碘苯甲酸,收率92%。再以水为溶剂,70～73℃下用2KHSO5-KHSO4-K2SO4氧化得1 羟基 1,2 苯碘酰 3(1H) 酮 1 氧化物(IBX),收率81%,总收率74 5%。然后用IBX为氧化剂室温氧化6 溴青霉烷酸二苯甲酯得6 溴青霉烷酸二苯甲酯亚砜,最后6 溴青霉烷酸二苯甲酯亚砜经超声波锌粉脱溴制得青霉烷酸二苯甲酯亚砜。在青霉烷酸二苯甲酯亚砜的合成中,每步反应产物不经分离,总收率82%。尤其在氧化反应中,用IBX代替了高质量分数的过氧乙酸,使反应在室温下进行,易于控制。反应过程绿色化,提高了原子经济性。产品用1HNMR、IR表征。     

Synthesis of polyfunctionally substituted pyridine-2-(1H)-thiones containing a sulfone moiety

1-Phenyl-2-(phenylsulfonyl)ethanone (1) reacts with DMFDMA to give enamine 2, which upon treatment with cyanothioacetamide affords 3-cyano-5-benzenesulfonyl-4-phenylpyridine-2(1H)-thione (4), a compound that can also be obtained by the reaction of 1-benzenesulfonyl-1-benzoyl-2-ethoxyethene (3) with cyanothioacetamide. The reaction of 2-thiocarbamoylacetamide (8a) and N-phenyl-2-thiocarbamoylacetamide (8b) with 3-aryl-2-benzenesulfonylacrylonitrile (9a– c) affords 10a–f. The methylation of 10d–f with methyl iodide results in the formation of S-methyl derivatives (12a–c). Compound 12c can be obtained by the reaction of 13 with 9c.     

1-硝基-2-(2,6-二氨基-4(3H)-氧代嘧啶-5-基)-4-(4-乙氧甲酰苯基)丁烷的合成

1-硝基-2-(2,6-二氨基-4(3H)-氧代嘧啶-5-基)-4-(4-乙氧甲酰苯基)丁烷是合成培美曲塞二钠的关键中间体。研究了以4-碘苯甲酸,2,6-二氨基-4-羟基嘧啶为原料,经酯化,加成,缩合,消除,加成,得目标产物。本法收率高,适合工业化生产。     

5-[(4-氨基苯基)二氮烯基]嘧啶-2,4,6(1H,3H,5H)-三酮的合成

以对硝基苯胺和巴比妥酸为原料,通过重氮化及偶合反应合成了5-[(4-硝基苯基)二氮烯基]嘧啶-2,4,6(1H,3H,5H)-三酮(A),化合物A经硫化物还原,得到单偶氮化合物5-[(4-氨基苯基)二氮烯基]嘧啶-2,4,6(1H,3H,5H)-三酮(B),该化合物可作为重氮组分与一些具有活泼氢的偶合组分反应,从而制备出酰胺键多、对称性高及稳定性强的双偶氮化合物。考察了还原剂用量、反应时间及反应温度对化合物B收率的影响,结果表明:投料比n(A)∶n(Na2S)=1∶1.7,105℃下回流48h,化合物B的收率为84.6%。利用1H NMR、FT-IR及元素分析对产物的结构进行了表征。