The toxicity of acetaldehyde and age related changes on oxidoreductases in the liver,brain, kidney, and musele of female albino rats (Wistar strain) were studied. The specific activities of lactate [LDH], isocitrate [...The toxicity of acetaldehyde and age related changes on oxidoreductases in the liver,brain, kidney, and musele of female albino rats (Wistar strain) were studied. The specific activities of lactate [LDH], isocitrate [ICDH (NAD/NADP)], succinate [SDH], malate [MDH], glutamate [GDH] and glucose-6-Phosphate [G-6-PDH] dehydrogenases were signifieantly inereased as a function of age. However, acetaldehyde treatment significantly inhibited oxidoreductases in the tissues of 21, 90 and 180 day old rats. Liver enzymes of young (21 days) rats exhibited greater sensitivity to acetaldehyde toxicity. Similar inhibition of oxidoreductases in brain and kidney of adult (180 days) rats treated with acetaldehyde was observed. LDH and GDH as compared to other enzymes studied showed higher susceptibility to acetaldehyde toxicity. The differential sensitivity of tissues and inhibition of oxidoreductases by acetaldehyde as a function of age could be attributed to hypoxic conditions, energy crisis, and mitochondrial structural changes. The results suggest that acetaldehyde affects oxidation of glucose via HMP shuni pathway, glycolytic pathway and Krebs cycle resulting in the impairment of carbohydrate metabolism展开更多
Azoreductases are involved in the bioremediation by bacteria of azo dyes found in waste water.In the gut flora,they activate azo pro-drugs,which are used for treatment of inflammatory bowel disease,releasing the activ...Azoreductases are involved in the bioremediation by bacteria of azo dyes found in waste water.In the gut flora,they activate azo pro-drugs,which are used for treatment of inflammatory bowel disease,releasing the active component 5-aminosalycilic acid.The bacterium P.aeruginosa has three azoreductase genes,paAzoR1,paAzoR2 and paAzoR3,which as recombinant enzymes have been shown to have different substrate specificities.The mechanism of azoreduction relies upon tautomerisation of the substrate to the hydrazone form.We report here the characterization of the P.aeruginosa azoreductase enzymes,including determining their thermostability,cofactor preference and kinetic constants against a range of their favoured substrates.The expression levels of these enzymes during growth of P.aeruginosa are altered by the presence of azo substrates.It is shown that enzymes that were originally described as azoreductases,are likely to act as NADH quinone oxidoreductases.The low sequence identities observed among NAD(P)H quinone oxidoreductase and azoreductase enzymes suggests convergent evolution.展开更多
Objective Hepatocellular carcinoma(HCC)is the third leading cause of cancer-associated death worldwide.As a first-line drug for advanced HCC treatment,lenvatinib faces a significant hurdle due to the development of bo...Objective Hepatocellular carcinoma(HCC)is the third leading cause of cancer-associated death worldwide.As a first-line drug for advanced HCC treatment,lenvatinib faces a significant hurdle due to the development of both intrinsic and acquired resistance among patients,and the underlying mechanism remains largely unknown.The present study aims to identify the pivotal gene responsible for lenvatinib resistance in HCC,explore the potential molecular mechanism,and propose combinatorial therapeutic targets for HCC management.Methods Cell viability and colony formation assays were conducted to evaluate the sensitivity of cells to lenvatinib and dicoumarol.RNA-Seq was used to determine the differences in transcriptome between parental cells and lenvatinib-resistant(LR)cells.The upregulated genes were analyzed by GO and KEGG analyses.Then,qPCR and Western blotting were employed to determine the relative gene expression levels.Afterwards,the intracellular reactive oxygen species(ROS)and apoptosis were detected by flow cytometry.Results PLC-LR and Hep3B-LR were established.There was a total of 116 significantly upregulated genes common to both LR cell lines.The GO and KEGG analyses indicated that these genes were involved in oxidoreductase and dehydrogenase activities,and reactive oxygen species pathways.Notably,NAD(P)H:quinone oxidoreductase 1(NQO1)was highly expressed in LR cells,and was involved in the lenvatinib resistance.The high expression of NQO1 decreased the production of ROS induced by lenvatinib,and subsequently suppressed the apoptosis.The combination of lenvatinib and NQO1 inhibitor,dicoumarol,reversed the resistance of LR cells.Conclusion The high NQO1 expression in HCC cells impedes the lenvatinib-induced apoptosis by regulating the ROS levels,thereby promoting lenvatinib resistance in HCC cells.展开更多
CuCl-catalyzed oxidative N-demethylation of arylamines proceeded in the presence of tert-butyl hydroperoxide. The one-electron transfer route of oxidative N-demethylation competed favorably with the H-atom abstraction...CuCl-catalyzed oxidative N-demethylation of arylamines proceeded in the presence of tert-butyl hydroperoxide. The one-electron transfer route of oxidative N-demethylation competed favorably with the H-atom abstraction route.展开更多
BACKGROUND Quinine oxidoreductase 1(NQO1)plays a vital role in protecting normal cells against oxidative damage and electrophilic attack.It is highly expressed in many solid tumors,suggesting a role in cancer developm...BACKGROUND Quinine oxidoreductase 1(NQO1)plays a vital role in protecting normal cells against oxidative damage and electrophilic attack.It is highly expressed in many solid tumors,suggesting a role in cancer development and progression.However,the role of NQO1 in gastric cancer and its effect on cancer development and prognosis have not been fully investigated.AIM To investigate the clinical relevance of NQO1 protein expression in gastric cancer and to explore the potential of NQO1 to serve as a prognostic biomarker and therapeutic target.METHODS In this retrospective study,gastric cancer specimens of 175 patients who were treated between 1995 and 2011 were subjected to immunohistochemistry analyses for NQO1.The correlation of NQO1 expression with gastric cancer prognosis and clinical and pathological parameters was investigated.RESULTS NQO1 protein was overexpressed in 59.43%(104/175)of the analyzed samples.Overexpression of NQO1 was associated with a significantly inferior prognosis.In addition,multivariate analysis suggested that NQO1 overexpression,along with tumor stage and patient age,are prominent prognostic biomarkers for gastric cancer.Moreover,NQO1 overexpression was correlated to a better response to 5-fluorouracil(5-FU)-based adjuvant chemotherapy.CONCLUSION NQO1 overexpression is associated with a significantly poor prognosis and better response to 5-FU in patients with gastric cancer.These findings are relevant for improving therapeutic approaches for gastric cancer patients.展开更多
AIM： To investigate the expression and activity of NAD（P）H quinone oxidoreductase 1 （NQO1） in human liver specimens obtained from patients with liver damage due to acetaminophen （APAP） overdose or primary bilia...AIM： To investigate the expression and activity of NAD（P）H quinone oxidoreductase 1 （NQO1） in human liver specimens obtained from patients with liver damage due to acetaminophen （APAP） overdose or primary biliary cirrhosis （PBC）. METHODS： NQOt activity was determined in cytosol from normal, APAP and PBC liver specimens. Western blot and immunohistochemical staining were used to determine patterns of NQO1 expression using a specific antibody against NQO1. RESULTS： NQO1 protein was very low in normal human livers. In both APAP and PBC livers, there was strong induction of NQO1 protein levels on Western blot. Correspondingly, significant up-regulation of enzyme activity （16- and 22-fold, P〈0.05） was also observed in APAP and PBC livers, respectively. Immunohistochemical analysis highlighted injury-specific patterns of NQO1 staining in both APAP and PBC livers. CONCLUSION： These data demonstrate that NQO1 protein and activity are markedly induced in human livers during both APAP overdose and PBC. Up-regulation of this cytoprotective enzyme may represent an adaptive stress response to limit further disease progression by detoxifying reactive species.展开更多
2-ketoisovalerate ferredoxin oxidoreductase (VOR) is a key enzyme in hyperthermophiles catalyzing the coenzyme A-dependent oxidative decarboxylation of aliphatic amino acid-derived 2-keto acids. The enzyme purified un...2-ketoisovalerate ferredoxin oxidoreductase (VOR) is a key enzyme in hyperthermophiles catalyzing the coenzyme A-dependent oxidative decarboxylation of aliphatic amino acid-derived 2-keto acids. The enzyme purified under anaerobic conditions from a hyperthermophilic archaeon, Thermococcus profundus, is a hetero-octamer (αβγδ)2 consisting of four different subunits, α = 45 kDa, β = 31 kDa, γ = 22 kDa and δ = 13 kDa, respectively, and it has three [4Fe-4S] clusters per αβγδ-protomer, similar to other ferredoxin oxidoreductases. In the present study, the native enzyme was purified from this strain and crystallized to give rod-like crystals that were suitable for X-ray diffraction experiments. The crystals belonged to space group P41212, with unit-cell parameters a = b = 136.20 ?, c = 221.07 ?. Diffraction images were processed to a resolution of 3.0 ?. The data collected so far indicate the approximate molecular boundaries and a partial main-chain trace of the enzyme.展开更多
Background:Aldo-keto oxidoreductase(AKR)inhibitors could reverse the resistance of several cancer cells to cis-platin,but their role in resistance remains unclear.Methods:We verified the difference of AKR1Cs expressio...Background:Aldo-keto oxidoreductase(AKR)inhibitors could reverse the resistance of several cancer cells to cis-platin,but their role in resistance remains unclear.Methods:We verified the difference of AKR1Cs expression by Western blot,RNA sequencing and qRT-PCR.The differences of AKR1Cs expression were analyzed and inferred.Use Assay of NADH and NAD^(+)content to verify the inference.The Docking experience was used to verify the affinity between MPA,MCFLA,MLS and AKR1C3.Results:Our RNA-seq results showed de novo NAD biosynthesis-related genes and NAD(P)H-dependent oxidoreductases were significantly upregulated in cis-platin-resistant HepG2 hepatic cancer cells(HepG2-RC cells)compared with HepG2 cells.At least 63 NAD(P)H-dependent reductase/oxidases were upregulated in HepG2-RC cells at least twofold.Knockdown of AKR1Cs could increase cis-platin sensitivity in HepG2-RC cells about two-fold.Interestingly,the AKR1C inhibitor meclofenamic acid could increase the cis-platin sensitivity of HepG2-RC cells about eight-fold,indicating that the knockdown of AKR1Cs only partially reversed the resistance.Meanwhile,the amount of total NAD and the ratio of NADH/NAD^(+)were increased in HepG2-RC cells compared with HepG2 cells.The ratio of NADH/NAD^(+)in HepG2-RC cells was almost seven-fold higher than in HepG2 or HL-7702 cells.Increased NADH expression could be explained as a directly operating antioxidant to scavenge cis-platin-induced radicals.Conclusion:We report here that NADH,which is produced by NAD(P)Hdependent oxidoreductases,plays a key role in the AKR-associated cis-platin resistance of HepG2 hepatic cancer cells.展开更多
文摘The toxicity of acetaldehyde and age related changes on oxidoreductases in the liver,brain, kidney, and musele of female albino rats (Wistar strain) were studied. The specific activities of lactate [LDH], isocitrate [ICDH (NAD/NADP)], succinate [SDH], malate [MDH], glutamate [GDH] and glucose-6-Phosphate [G-6-PDH] dehydrogenases were signifieantly inereased as a function of age. However, acetaldehyde treatment significantly inhibited oxidoreductases in the tissues of 21, 90 and 180 day old rats. Liver enzymes of young (21 days) rats exhibited greater sensitivity to acetaldehyde toxicity. Similar inhibition of oxidoreductases in brain and kidney of adult (180 days) rats treated with acetaldehyde was observed. LDH and GDH as compared to other enzymes studied showed higher susceptibility to acetaldehyde toxicity. The differential sensitivity of tissues and inhibition of oxidoreductases by acetaldehyde as a function of age could be attributed to hypoxic conditions, energy crisis, and mitochondrial structural changes. The results suggest that acetaldehyde affects oxidation of glucose via HMP shuni pathway, glycolytic pathway and Krebs cycle resulting in the impairment of carbohydrate metabolism
文摘Azoreductases are involved in the bioremediation by bacteria of azo dyes found in waste water.In the gut flora,they activate azo pro-drugs,which are used for treatment of inflammatory bowel disease,releasing the active component 5-aminosalycilic acid.The bacterium P.aeruginosa has three azoreductase genes,paAzoR1,paAzoR2 and paAzoR3,which as recombinant enzymes have been shown to have different substrate specificities.The mechanism of azoreduction relies upon tautomerisation of the substrate to the hydrazone form.We report here the characterization of the P.aeruginosa azoreductase enzymes,including determining their thermostability,cofactor preference and kinetic constants against a range of their favoured substrates.The expression levels of these enzymes during growth of P.aeruginosa are altered by the presence of azo substrates.It is shown that enzymes that were originally described as azoreductases,are likely to act as NADH quinone oxidoreductases.The low sequence identities observed among NAD(P)H quinone oxidoreductase and azoreductase enzymes suggests convergent evolution.
基金supported by the Global Select Project(No.DJK-LX-2022001)of the Institute of Health and Medicine,Hefei Comprehensive National Science Center.
文摘Objective Hepatocellular carcinoma(HCC)is the third leading cause of cancer-associated death worldwide.As a first-line drug for advanced HCC treatment,lenvatinib faces a significant hurdle due to the development of both intrinsic and acquired resistance among patients,and the underlying mechanism remains largely unknown.The present study aims to identify the pivotal gene responsible for lenvatinib resistance in HCC,explore the potential molecular mechanism,and propose combinatorial therapeutic targets for HCC management.Methods Cell viability and colony formation assays were conducted to evaluate the sensitivity of cells to lenvatinib and dicoumarol.RNA-Seq was used to determine the differences in transcriptome between parental cells and lenvatinib-resistant(LR)cells.The upregulated genes were analyzed by GO and KEGG analyses.Then,qPCR and Western blotting were employed to determine the relative gene expression levels.Afterwards,the intracellular reactive oxygen species(ROS)and apoptosis were detected by flow cytometry.Results PLC-LR and Hep3B-LR were established.There was a total of 116 significantly upregulated genes common to both LR cell lines.The GO and KEGG analyses indicated that these genes were involved in oxidoreductase and dehydrogenase activities,and reactive oxygen species pathways.Notably,NAD(P)H:quinone oxidoreductase 1(NQO1)was highly expressed in LR cells,and was involved in the lenvatinib resistance.The high expression of NQO1 decreased the production of ROS induced by lenvatinib,and subsequently suppressed the apoptosis.The combination of lenvatinib and NQO1 inhibitor,dicoumarol,reversed the resistance of LR cells.Conclusion The high NQO1 expression in HCC cells impedes the lenvatinib-induced apoptosis by regulating the ROS levels,thereby promoting lenvatinib resistance in HCC cells.
基金Supported by the National Natural Science Foundation of China(No.20572058)
文摘CuCl-catalyzed oxidative N-demethylation of arylamines proceeded in the presence of tert-butyl hydroperoxide. The one-electron transfer route of oxidative N-demethylation competed favorably with the H-atom abstraction route.
基金Supported by the National Natural Science Foundation of China,No.31971188 and No.81773189the Nature Science Foundation of Zhejiang Province,China,No.LQ16H160004 and No.LY17H270002The Hygiene Department of Zhejiang,No.2016KYB139.
文摘BACKGROUND Quinine oxidoreductase 1(NQO1)plays a vital role in protecting normal cells against oxidative damage and electrophilic attack.It is highly expressed in many solid tumors,suggesting a role in cancer development and progression.However,the role of NQO1 in gastric cancer and its effect on cancer development and prognosis have not been fully investigated.AIM To investigate the clinical relevance of NQO1 protein expression in gastric cancer and to explore the potential of NQO1 to serve as a prognostic biomarker and therapeutic target.METHODS In this retrospective study,gastric cancer specimens of 175 patients who were treated between 1995 and 2011 were subjected to immunohistochemistry analyses for NQO1.The correlation of NQO1 expression with gastric cancer prognosis and clinical and pathological parameters was investigated.RESULTS NQO1 protein was overexpressed in 59.43%(104/175)of the analyzed samples.Overexpression of NQO1 was associated with a significantly inferior prognosis.In addition,multivariate analysis suggested that NQO1 overexpression,along with tumor stage and patient age,are prominent prognostic biomarkers for gastric cancer.Moreover,NQO1 overexpression was correlated to a better response to 5-fluorouracil(5-FU)-based adjuvant chemotherapy.CONCLUSION NQO1 overexpression is associated with a significantly poor prognosis and better response to 5-FU in patients with gastric cancer.These findings are relevant for improving therapeutic approaches for gastric cancer patients.
文摘AIM： To investigate the expression and activity of NAD（P）H quinone oxidoreductase 1 （NQO1） in human liver specimens obtained from patients with liver damage due to acetaminophen （APAP） overdose or primary biliary cirrhosis （PBC）. METHODS： NQOt activity was determined in cytosol from normal, APAP and PBC liver specimens. Western blot and immunohistochemical staining were used to determine patterns of NQO1 expression using a specific antibody against NQO1. RESULTS： NQO1 protein was very low in normal human livers. In both APAP and PBC livers, there was strong induction of NQO1 protein levels on Western blot. Correspondingly, significant up-regulation of enzyme activity （16- and 22-fold, P〈0.05） was also observed in APAP and PBC livers, respectively. Immunohistochemical analysis highlighted injury-specific patterns of NQO1 staining in both APAP and PBC livers. CONCLUSION： These data demonstrate that NQO1 protein and activity are markedly induced in human livers during both APAP overdose and PBC. Up-regulation of this cytoprotective enzyme may represent an adaptive stress response to limit further disease progression by detoxifying reactive species.
文摘2-ketoisovalerate ferredoxin oxidoreductase (VOR) is a key enzyme in hyperthermophiles catalyzing the coenzyme A-dependent oxidative decarboxylation of aliphatic amino acid-derived 2-keto acids. The enzyme purified under anaerobic conditions from a hyperthermophilic archaeon, Thermococcus profundus, is a hetero-octamer (αβγδ)2 consisting of four different subunits, α = 45 kDa, β = 31 kDa, γ = 22 kDa and δ = 13 kDa, respectively, and it has three [4Fe-4S] clusters per αβγδ-protomer, similar to other ferredoxin oxidoreductases. In the present study, the native enzyme was purified from this strain and crystallized to give rod-like crystals that were suitable for X-ray diffraction experiments. The crystals belonged to space group P41212, with unit-cell parameters a = b = 136.20 ?, c = 221.07 ?. Diffraction images were processed to a resolution of 3.0 ?. The data collected so far indicate the approximate molecular boundaries and a partial main-chain trace of the enzyme.
基金supported by the Science and Technology Development Plan Project of Jilin Province,China[20200708101YY]The Foundation of Jilin Province Science and Technology Department[20200801062GH].
文摘Background:Aldo-keto oxidoreductase(AKR)inhibitors could reverse the resistance of several cancer cells to cis-platin,but their role in resistance remains unclear.Methods:We verified the difference of AKR1Cs expression by Western blot,RNA sequencing and qRT-PCR.The differences of AKR1Cs expression were analyzed and inferred.Use Assay of NADH and NAD^(+)content to verify the inference.The Docking experience was used to verify the affinity between MPA,MCFLA,MLS and AKR1C3.Results:Our RNA-seq results showed de novo NAD biosynthesis-related genes and NAD(P)H-dependent oxidoreductases were significantly upregulated in cis-platin-resistant HepG2 hepatic cancer cells(HepG2-RC cells)compared with HepG2 cells.At least 63 NAD(P)H-dependent reductase/oxidases were upregulated in HepG2-RC cells at least twofold.Knockdown of AKR1Cs could increase cis-platin sensitivity in HepG2-RC cells about two-fold.Interestingly,the AKR1C inhibitor meclofenamic acid could increase the cis-platin sensitivity of HepG2-RC cells about eight-fold,indicating that the knockdown of AKR1Cs only partially reversed the resistance.Meanwhile,the amount of total NAD and the ratio of NADH/NAD^(+)were increased in HepG2-RC cells compared with HepG2 cells.The ratio of NADH/NAD^(+)in HepG2-RC cells was almost seven-fold higher than in HepG2 or HL-7702 cells.Increased NADH expression could be explained as a directly operating antioxidant to scavenge cis-platin-induced radicals.Conclusion:We report here that NADH,which is produced by NAD(P)Hdependent oxidoreductases,plays a key role in the AKR-associated cis-platin resistance of HepG2 hepatic cancer cells.
