NAD(P)H determination
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This work presents a yeast-cell vitality-assessment method based on on-line intracellular fluorescence measurement. The intracellular NAD(P)H fluorescence of a cell suspension is recorded during transition from aerobic to anaerobic conditions and the output signal is evaluated as a measure of yeast vitality (quality). This fluorescence method showed a highly satisfactory correlation with even low dead cell numbers where the acidification power test could not be applied.
Associations of transcript levels of oxidative stress-modifying genes SOD2, SOD3, NQO1 and NQO2 and their functional single nucleotide polymorphisms (SNPs) rs4880, rs1799895, rs2536512, rs699473, rs1800566 and rs1143684 with prognosis of breast cancer patients were studied. SNPs were assessed by allelic discrimination in a cohort of 321 breast cancer patients from the Czech Republic. Transcript levels were determined by real-time polymerase chain reaction (PCR) with absolute quantification in tumor and adjacent non-neoplastic control tissues. Both genotypes and transcript levels were then compared with available clinical data on patients. Patients carrying low activity allele Leu in NQO2 rs1143684 had a greater incidence of stage 0 or I disease (i.e., better prognosis) than patients with the Phe/Phe genotype. This association was more evident in patients without expression of progesterone receptors (p = 0.031). Patients carrying the Thr allele in SOD3 rs2536512 SNP had a significantly greater incidence of tumors expressing estrogen receptors than patients carrying the Ala/Ala genotype (p = 0.007). SOD3 transcript level was significantly higher in grade 1 or 2 tumors than in grade 3 tumors (p = 0.006). Patients carrying T allele in SOD3 rs699473 SNP had significantly poorer progression-free survival (PFS) than patients carrying the CC genotype (p = 0.038). The same applied to the subgroup of patients treated by hormonal regimens (p = 0.021). Patients carrying the high activity Ala/Ala genotype in SOD2 (rs4880) had significantly poorer PFS than Val allele carriers in the group treated by cyclophosphamide but not hormonal regimens (p = 0.004). Our results suggest that NQO2, SOD2 and SOD3 may significantly modify prognosis of breast cancer patients and that their significance should be further characterized.
- MeSH
- chinonreduktasy biosyntéza genetika MeSH
- DNA nádorová krev genetika MeSH
- genetická transkripce MeSH
- jednonukleotidový polymorfismus MeSH
- kohortové studie MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA genetika metabolismus MeSH
- NAD(P)H dehydrogenasa (chinon) biosyntéza genetika MeSH
- nádorové biomarkery biosyntéza genetika MeSH
- nádory prsu krev enzymologie genetika patologie MeSH
- přežití bez známek nemoci MeSH
- superoxiddismutasa biosyntéza genetika MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)-the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1⁻/⁻, Cyp1a2⁻/⁻ and Cyp1a1/1a2⁻/⁻ knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential.
- MeSH
- adukty DNA metabolismus MeSH
- balkánská nefropatie enzymologie genetika metabolismus MeSH
- buněčné linie MeSH
- cytochrom P-450 CYP1A1 nedostatek genetika metabolismus MeSH
- cytochrom P-450 CYP1A2 nedostatek genetika metabolismus MeSH
- cytosol enzymologie metabolismus MeSH
- játra účinky léků enzymologie metabolismus MeSH
- kyseliny aristolochové farmakokinetika toxicita MeSH
- lidé MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši transgenní MeSH
- myši MeSH
- NAD(P)H dehydrogenasa (chinon) biosyntéza metabolismus MeSH
- western blotting MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Sudan I (1-phenylazo-2-hydroxynaphthol) is a suspected human carcinogen causing tumors in the livers and urinary bladders of rats, mice, and rabbits. Here, we investigated for the first time the influence of Sudan I exposure on the expression of several biotransformation enzymes in the livers, kidneys, and lungs of rats concomitantly at the mRNA and protein levels and assayed their enzymatic activities. We also studied its effect on the formation of Sudan I-derived DNA adducts in vitro. Sudan I increased the total amounts of cytochrome P450 (P450) in all organs tested. Western blots using antibodies raised against various P450s, NADPH:P450 reductase, and NAD(P)H:quinone oxidoreductase 1 (NQO1) showed that the expression of P450 1A1 and NQO1 was induced in the liver, kidney, and lung of rats treated with Sudan I. The higher protein levels correlated with increased enzyme activities of P450 1A1/2 and NQO1. Furthermore, 9.9-, 5.9-, and 2.8-fold increases in the formation of Sudan I oxidative metabolites catalyzed by microsomes isolated from the liver, kidney, and lung, respectively, of rats treated with Sudan I were found. The relative amounts of P450 1A and NQO1 mRNA, measured by real-time polymerase chain reaction (RT-PCR) analysis, demonstrated that Sudan I induced the expression of P450 1A1 and NQO1 mRNA in the liver, kidney, and lung, and of P450 1A2 mRNA in kidney and lung. Finally, microsomes isolated from livers, kidneys, and lungs of Sudan I exposed rats more effectively catalyzed the formation of Sudan I-DNA adducts than microsomes from organs of control rats. This was attributable to the higher P450 1A1 expression. Because P450 1A1 is playing a major role in the bioactivation of Sudan I in rat and human systems, its induction by Sudan I may have a profound effect on cancer risk by this azo dye. In addition, the induction of P450 1A1/2 and NQO1 enzymes can influence individual human susceptibility to other environmental carcinogens and have an effect on cancer risk.
- MeSH
- adukty DNA účinky léků metabolismus MeSH
- barvicí látky metabolismus MeSH
- cytochrom P-450 CYP1A1 genetika metabolismus MeSH
- cytosol účinky léků enzymologie MeSH
- játra účinky léků enzymologie MeSH
- karcinogeny metabolismus MeSH
- krysa rodu rattus MeSH
- ledviny účinky léků enzymologie MeSH
- messenger RNA genetika MeSH
- mikrozomy účinky léků enzymologie MeSH
- NAD(P)H dehydrogenasa (chinon) genetika metabolismus MeSH
- naftoly metabolismus MeSH
- plíce účinky léků enzymologie MeSH
- potkani Wistar MeSH
- upregulace účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVE: The aim of this study was to further clarify the recently reported role of NAD(P)H:quinone oxidoreductase 1 (NQO1) as a strong prognostic and predictive factor in breast cancer. METHODS: NQO1 transcript levels were monitored in mammary tumors by real-time polymerase chain reaction. NQO1 protein levels were immunohistochemically determined in formalin-fixed paraffin-embedded tissues. NQO1 polymorphism (Pro187Ser, rs1800566) was also assessed. Evaluation (N=52) and validation (N=53) sets were analyzed subsequently. RESULTS: Carriers of variant NQO1-Ser allele had significantly more frequently NQO1-negative protein expression (P=0.001) in both sets. NQO1 transcript levels in samples with negative protein expression were significantly lower than in those with positive NQO1 protein expression (P=0.007) in both sets. Patients with stages 0/I/II had more often positive NQO1 protein expression than patients with stages III/IV (P=0.022) in the evaluation set. Significant association between NQO1 protein expression and TP53 protein status was also found (P=0.037). However, both associations were not replicated by analysis of the validation set. Analysis of both sets combined did not show significant association of NQO1 protein expression either with stage (P=0.231) or with TP53 protein status (P>0.999). Thus, the results observed in the evaluation set were effects of small sample size. CONCLUSION: The role of NQO1 in human mammary gland carcinogenesis does not seem to be directly associated with classical clinico-pathological factors.
- MeSH
- genetická predispozice k nemoci MeSH
- imunohistochemie MeSH
- jednonukleotidový polymorfismus genetika MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA genetika metabolismus MeSH
- NAD(P)H dehydrogenasa (chinon) genetika MeSH
- nádory prsu enzymologie genetika patologie MeSH
- prolin genetika MeSH
- regulace genové exprese u nádorů MeSH
- serin genetika MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
UNLABELLED: 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.
- MeSH
- acetyltransferasy metabolismus MeSH
- adukty DNA chemie metabolismus MeSH
- aromatické hydroxylasy metabolismus MeSH
- benz(a)anthraceny chemie metabolismus MeSH
- biokatalýza MeSH
- enzymy metabolismus MeSH
- kyseliny aristolochové chemie metabolismus MeSH
- lidé MeSH
- molekulární modely * MeSH
- NAD(P)H dehydrogenasa (chinon) metabolismus MeSH
- sulfotransferasy metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Our knowledge on the genetic diversity of the human genome is exponentially growing. However, our capacity to establish genotype-phenotype correlations on a large scale requires a combination of detailed experimental and computational work. This is a remarkable task in human proteins which are typically multifunctional and structurally complex. In addition, mutations often prevent the determination of mutant high-resolution structures by X-ray crystallography. We have characterized here the effects of five mutations in the active site of the disease-associated NQO1 protein, which are found either in cancer cell lines or in massive exome sequencing analysis in human population. Using a combination of H/D exchange, rapid-flow enzyme kinetics, binding energetics and conformational stability, we show that mutations in both sets may cause counterintuitive functional effects that are explained well by their effects on local stability regarding different functional features. Importantly, mutations predicted to be highly deleterious (even those affecting the same protein residue) may cause mild to catastrophic effects on protein function. These functional effects are not well explained by current predictive bioinformatic tools and evolutionary models that account for site conservation and physicochemical changes upon mutation. Our study also reinforces the notion that naturally occurring mutations not identified as disease-associated can be highly deleterious. Our approach, combining protein biophysics and structural biology tools, is readily accessible to broadly increase our understanding of genotype-phenotype correlations and to improve predictive computational tools aimed at distinguishing disease-prone against neutral missense variants in the human genome.
- MeSH
- katalytická doména genetika MeSH
- lidé MeSH
- missense mutace * MeSH
- molekulární biologie MeSH
- mutace MeSH
- NAD(P)H dehydrogenasa (chinon) genetika metabolismus MeSH
- proteiny * chemie MeSH
- výpočetní biologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- fagocytární baktericidní dysfunkce * diagnóza MeSH
- fagocytóza * fyziologie imunologie MeSH
- fluorescenční barviva MeSH
- imunologické testy MeSH
- lidé MeSH
- luminiscenční měření MeSH
- NADPH-oxidasy fyziologie imunologie MeSH
- neutrofily imunologie patologie MeSH
- respirační vzplanutí MeSH
- tetrazoliové soli MeSH
- Check Tag
- lidé MeSH
3-Nitrobenzanthrone (3-NBA), a carcinogenic air pollutant, was investigated for its ability to induce cytochrome P450 (CYP) 1A1/2 and NAD(P)H:quinone oxidoreductase (NQO1) in liver, kidney and lung of rats treated by intra-tracheal instillation. The organs used were from a previous study performed to determine the persistence of 3-NBA-derived DNA adducts in target and non-target tissues (Bieler et al., Carcinogenesis 28 (2007) 1117-1121, [22]). NQO1 is the enzyme reducing 3-NBA to N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) and CYP1A enzymes oxidize a human metabolite of 3-NBA, 3-aminobenzanthrone (3-ABA), to yield the same reactive intermediate. 3-NBA and 3-ABA are both activated to species forming DNA adducts by cytosols and/or microsomes isolated from rat lung, the target organ for 3-NBA carcinogenicity, and from liver and kidney. Each compound generated the same five DNA adducts detectable by (32)P-postlabelling. When hepatic cytosols from rats treated with 0.2 or 2mg/kg body weight of 3-NBA were incubated with 3-NBA, DNA adduct formation was 3.2- and 8.6-fold higher, respectively, than in incubations with cytosols from control animals. Likewise, cytosols isolated from lungs and kidneys of rats exposed to 3-NBA more efficiently activated 3-NBA than those of control rats. This increase corresponded to an increase in protein levels and enzymatic activities of NQO1. Incubations of hepatic, pulmonary or renal microsomes of 3-NBA-treated rats with 3-ABA led to an 9.6-fold increase in DNA-adduct formation relative to controls. The highest induction in DNA-adduct levels was found in lung. The stimulation of DNA-adduct formation correlated with expression of CYP1A1/2 induced by the intra-tracheal instillation of 3-NBA. The results demonstrate that 3-NBA induces NQO1 and CYP1A1/2 in livers, lungs and kidneys of rats after intra-tracheal instillation, thereby enhancing its own genotoxic and carcinogenic potential.
- MeSH
- adukty DNA MeSH
- benz(a)anthraceny metabolismus farmakologie MeSH
- cytochrom P-450 CYP1A1 metabolismus MeSH
- cytochrom P-450 CYP1A2 metabolismus MeSH
- cytosol účinky léků MeSH
- enzymová indukce účinky léků MeSH
- játra enzymologie MeSH
- karcinogeny farmakologie MeSH
- krysa rodu rattus MeSH
- látky znečišťující vzduch farmakologie MeSH
- ledviny enzymologie MeSH
- mikrozomy účinky léků MeSH
- NAD(P)H dehydrogenasa (chinon) metabolismus MeSH
- plíce enzymologie MeSH
- potkani Sprague-Dawley MeSH
- trachea MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The antineoplastic agent ellipticine was investigated for its ability to induce the biotransformation enzyme NAD(P)H:quinone oxidoreductase (DT-diaphorase, EC 1.6.99.2) in male Wistar rats. Using the real-time polymerase chain reaction, the levels of NAD(P)H:quinone oxidoreductase mRNA were determined in livers, kidneys and lungs of rats treated intraperitoneally with ellipticine (40 mg/kg body weight) and of control (untreated) rats. Cytosolic fractions were isolated from the same tissues of control and ellipticine-treated rats and tested for NAD(P)H:quinone oxidoreductase protein expression and its enzymatic activity. The results demonstrate that ellipticine is a potent inducer of NAD(P)H:quinone oxidoreductase in rat livers and kidneys, while no induction of this enzyme was detectable in rat lungs. The increase in levels of NAD(P)H:quinone oxidoreductase mRNA correlates with the increase in expression of its protein and enzymatic activity, measured with menadione and 3-nitrobenzanthrone as substrates. The results, the identification of the potential of ellipticine to induce NAD(P)H:quinone oxidoreductase, suggest that this drug is capable of modulating biological efficiencies of the toxicants and/or drugs that are reductively metabolized by this enzyme.
