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Du J, Martin SM, Levine M, Wagner BA, Buettner GR, Wang SH, Taghiyev AF, Du C, Knudson CM, Cullen JJ. Mechanisms of ascorbate-induced cytotoxicity in pancreatic cancer. Clin Cancer Res 2010; 16:509-20. [PMID: 20068072 DOI: 10.1158/1078-0432.ccr-09-1713] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE Pharmacologic concentrations of ascorbate may be effective in cancer therapeutics. We hypothesized that ascorbate concentrations achievable with i.v. dosing would be cytotoxic in pancreatic cancer for which the 5-year survival is <3%. EXPERIMENTAL DESIGN Pancreatic cancer cell lines were treated with ascorbate (0, 5, or 10 mmol/L) for 1 hour, then viability and clonogenic survival were determined. Pancreatic tumor cells were delivered s.c. into the flank region of nude mice and allowed to grow at which time they were randomized to receive either ascorbate (4 g/kg) or osmotically equivalent saline (1 mol/L) i.p. for 2 weeks. RESULTS There was a time- and dose-dependent increase in measured H(2)O(2) production with increased concentrations of ascorbate. Ascorbate decreased viability in all pancreatic cancer cell lines but had no effect on an immortalized pancreatic ductal epithelial cell line. Ascorbate decreased clonogenic survival of the pancreatic cancer cell lines, which was reversed by treatment of cells with scavengers of H(2)O(2). Treatment with ascorbate induced a caspase-independent cell death that was associated with autophagy. In vivo, treatment with ascorbate inhibited tumor growth and prolonged survival. CONCLUSIONS These results show that pharmacologic doses of ascorbate, easily achievable in humans, may have potential for therapy in pancreatic cancer.
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Affiliation(s)
- Juan Du
- Department of Surgery, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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52
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Measurement of superoxide dismutase, catalase and glutathione peroxidase in cultured cells and tissue. Nat Protoc 2009; 5:51-66. [PMID: 20057381 DOI: 10.1038/nprot.2009.197] [Citation(s) in RCA: 812] [Impact Index Per Article: 54.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cells contain a large number of antioxidants to prevent or repair the damage caused by reactive oxygen species, as well as to regulate redox-sensitive signaling pathways. General protocols are described to measure the antioxidant enzyme activity of superoxide dismutase (SOD), catalase and glutathione peroxidase. The SODs convert superoxide radical into hydrogen peroxide and molecular oxygen, whereas the catalase and peroxidases convert hydrogen peroxide into water. In this way, two toxic species, superoxide radical and hydrogen peroxide, are converted to the harmless product water. Western blots, activity gels and activity assays are various methods used to determine protein and activity in both cells and tissue depending on the amount of protein required for each assay. Other techniques including immunohistochemistry and immunogold can further evaluate the levels of the various antioxidant enzymes in tissues and cells. In general, these assays require 24-48 h to complete.
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Gavriil M, Tsao CC, Mandiyan S, Arndt K, Abraham R, Zhang Y. Specific IKKbeta inhibitor IV blocks Streptonigrin-induced NF-kappaB activity and potentiates its cytotoxic effect on cancer cells. Mol Carcinog 2009; 48:678-84. [PMID: 19444813 DOI: 10.1002/mc.20550] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Many anticancer agents activate NF-kappaB, which plays an important role in the survival of cancer cells. Inhibition of NF-kappaB activity may therefore potentiate the efficacy of anticancer agents. We found that a previously used anticancer agent Streptonigrin (SN) was also a potent NF-kappaB inducer. Using a specific IKKbeta inhibitor IV (Podolin et al., J Pharmacol Exp Ther 2005; 312: 373-381), we revealed that the activation of NF-kappaB was mediated through DNA damage-induced activation of IKK complex. Furthermore, we demonstrated that SN-induced DNA damage was unrelated to reactive oxygen species but to the hydroquinone form of SN converted by the NAD(P)H:quinine oxidoreductase (NQO1). The study suggests that the combination of SN with IKK inhibitor may improve efficacy over the use of single agent.
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Affiliation(s)
- Maria Gavriil
- Department of Oncology, Wyeth Research, Pearl River, New York, USA
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NAD(P)H:quinone oxidoreductase 1 Pro187Ser polymorphism and expression do not cosegregate with clinico-pathological characteristcs of human mammary tumors. Pharmacogenet Genomics 2009; 19:505-12. [DOI: 10.1097/fpc.0b013e32832cf9cf] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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55
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Schipper DJ, El-Salfiti M, Whipp CJ, Fagnou K. Direct arylation of azine N-oxides with aryl triflates. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.03.077] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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56
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Cabello CM, Bair WB, Bause AS, Wondrak GT. Antimelanoma activity of the redox dye DCPIP (2,6-dichlorophenolindophenol) is antagonized by NQO1. Biochem Pharmacol 2009; 78:344-54. [PMID: 19394313 DOI: 10.1016/j.bcp.2009.04.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 04/14/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022]
Abstract
Altered redox homeostasis involved in the control of cancer cell survival and proliferative signaling represents a chemical vulnerability that can be targeted by prooxidant redox intervention. Here, we demonstrate that the redox dye 2,6-dichlorophenolindophenol (DCPIP) may serve as a prooxidant chemotherapeutic targeting human melanoma cells in vitro and in vivo. DCPIP-apoptogenicity observed in the human melanoma cell lines A375 and G361 was inversely correlated with NAD(P)H:quinone oxidoreductase (NQO1) expression levels. In A375 cells displaying low NQO1 activity, DCPIP induced apoptosis with procaspase-3 and PARP cleavage, whereas G361 cells expressing high levels of enzymatically active NQO1 were resistant to DCPIP-cytotoxicity. Genetic (siRNA) or pharmacological (dicoumarol) antagonism of NQO1 strongly sensitized G361 cells to DCPIP apoptogenic activity. DCPIP-cytotoxicity was associated with the induction of oxidative stress and rapid depletion of glutathione in A375 and NQO1-modulated G361 cells. Expression array analysis revealed a DCPIP-induced stress response in A375 cells with massive upregulation of genes encoding Hsp70B' (HSPA6), Hsp70 (HSPA1A), heme oxygenase-1 (HMOX1), and early growth response protein 1 (EGR1) further confirmed by immunodetection. Systemic administration of DCPIP displayed significant antimelanoma activity in the A375 murine xenograft model. These findings suggest feasibility of targeting tumors that display low NQO1 enzymatic activity using DCPIP.
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Affiliation(s)
- Christopher M Cabello
- Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724, USA
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57
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Husain K, Francois RA, Hutchinson SZ, Neuger AM, Lush R, Coppola D, Sebti S, Malafa MP. Vitamin E delta-tocotrienol levels in tumor and pancreatic tissue of mice after oral administration. Pharmacology 2009; 83:157-63. [PMID: 19142032 DOI: 10.1159/000190792] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 10/21/2008] [Indexed: 11/19/2022]
Abstract
Tocotrienols are natural vitamin E compounds that are known to have a neuroprotective effect at nanomolar concentration and anti-carcinogenic effect at micromolar concentration. In this report, we investigated the pharmacokinetics, tumor and pancreatic tissue levels, and toxicity of delta-tocotrienol in mice because of its anti-tumor activity against pancreatic cancer. Following a single oral administration of delta-tocotrienol at 100 mg/kg, the peak plasma concentration (C(max)) was 57 +/- 5 micromol/l, the time required to reach peak plasma concentration (T(max)) was 2 h and plasma half-life (t(1/2)) was 3.5 h. The delta-tocotrienol was cleared from plasma and liver within 24 h, but delayed from the pancreas. When mice were fed delta-tocotrienol for 6 weeks, the concentration in tumor tissue was 41 +/- 3.5 nmol/g. This concentration was observed with the oral dose (100 mg/kg) of delta-tocotrienol which inhibited tumor growth by 80% in our previous studies. Interestingly, delta-tocotrienol was 10-fold more concentrated in the pancreas than in the tumor. We observed no toxicity due to delta-tocotrienol as mice gained normal weight with no histopathological changes in tissues. Our data suggest that bioactive levels of delta-tocotrienol can be achieved in the pancreas following oral administration and supports its clinical investigation in pancreatic cancer.
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Affiliation(s)
- Kazim Husain
- Department of Gastrointestinal Oncology and Drug Discovery, Moffitt Cancer Center, Department of Oncological Sciences University of South Florida, Tampa, FL 33612, USA
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58
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NQO1 expression in pancreatic cancer and its potential use as a biomarker. Appl Immunohistochem Mol Morphol 2008; 16:24-31. [PMID: 18091324 DOI: 10.1097/pai.0b013e31802e91d0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDA) is rarely curable due to regional/metastatic spread at diagnosis. Identification of molecular markers may enhance diagnosis and early detection of PDA. The 2-electron reductase, NAD(P)H:quinone oxidoreductase (NQO1) has been found to be overexpressed in many solid tumors including PDA, and may be a useful clinically relevant diagnostic marker of malignancy. For this study, we used 37 surgical resection cases: 24 PDAs and 13 benign pancreatic tissue specimens. An additional 16 specimens from pancreatic endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) were included as a pilot series. NQO1 was detected by avidin-biotin based immunohistochemical and immunocytochemical methods. Both staining intensity and proportion of NQO1 positive tumor cells were scored. Moderate to strong (2 to 3+) staining for NQO1 was detected in 22/24 (92%) surgically resected PDAs, 9/9 (100%) EUS-FNAs with malignant diagnoses, one cytologically atypical but not diagnostic for malignancy EUS-FNA, and 1/6 (17%) EUS-FNAs initially diagnosed as negative for malignancy. Subsequent histologic assessment confirmed malignancy in all 9 cytologically positive EUS-FNAs and in the atypical case. The NQO1 positive case initially diagnosed as negative for malignancy showed no evidence of carcinoma on subsequent tissue biopsy. NQO1 staining was also observed in some benign ducts/cells; however, correlation of NQO1 expression with cellular morphology assessment minimizes the risk of false positive diagnosis. NQO1 is consistently overexpressed in PDA. Although NQO1 is observed in some benign tissue components, this marker may be a clinically useful diagnostic adjunct for detection of PDA, independent of tumor grade/stage.
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Volpato M, Abou-Zeid N, Tanner RW, Glassbrook LT, Taylor J, Stratford I, Loadman PM, Jaffar M, Phillips RM. Chemical synthesis and biological evaluation of a NAD(P)H:quinone oxidoreductase-1 targeted tripartite quinone drug delivery system. Mol Cancer Ther 2007; 6:3122-30. [DOI: 10.1158/1535-7163.mct-07-0519] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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60
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Gaikwad NW, Rogan EG, Cavalieri EL. Evidence from ESI-MS for NQO1-catalyzed reduction of estrogen ortho-quinones. Free Radic Biol Med 2007; 43:1289-98. [PMID: 17893042 PMCID: PMC2064005 DOI: 10.1016/j.freeradbiomed.2007.07.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 06/13/2007] [Accepted: 07/16/2007] [Indexed: 12/14/2022]
Abstract
Estrogen ortho-quinones have been implicated as ultimate carcinogenic metabolites of estrogens. The present conclusion that estrogen ortho-quinones are not substrates for NAD(P)H:quinone oxidoreductase (NQO1) stems from earlier reports. In this investigation, we were successful in circumventing the problem of nonenzymatic reduction of estrogen quinone by NAD(P)H, which led to the above conclusion, and for the first time we show that NQO1 catalyzes the reduction of estrogen quinones. Mass spectrometric binding studies involving estradiol-3,4-quinone or menadione with NQO1 clearly support the formation of an enzyme-substrate physical complex. However, the NQO1 mass spectrum did not alter after addition of cholesterol, the control. Two different strategies were employed to ascertain the NQO1 activity in estrogen quinone reduction. First, the ping-pong mechanism of NQO1 catalysis was utilized to overcome the problem of nonenzymatic reduction of the substrate by NADH. Second, tetrahydrofolic acid, which has a lower reducing potential, was used as an alternate cofactor. Both of these methods confirmed the reduction of estradiol-3,4-quinone by NQO1, when the assay mixtures were analyzed by UV or liquid chromatography-mass spectrometry. Furthermore, reduction of 9,10-phenanthrene quinone or menadione was observed using the reported assay conditions. Thus, clear evidence for the catalytic reduction of estrogen ortho-quinones by NQO1 has been obtained; its mechanism and implications are discussed.
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Affiliation(s)
| | | | - Ercole L. Cavalieri
- Corresponding Author Ercole L. Cavalieri, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805, Tel. 402-559-7237, Fax 402-559-8068, e-mail:
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61
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Abstract
Estrogen ortho-quinones have been implicated as ultimate carcinogenic metabolites of estrogens. The present conclusion that estrogen ortho-quinones are not substrates for NAD(P)H:quinone oxidoreductase (NQO1) stems from earlier reports. In this investigation, we were successful in circumventing the problem of nonenzymatic reduction of estrogen quinone by NAD(P)H, which led to the above conclusion, and for the first time we show that NQO1 catalyzes the reduction of estrogen quinones. Mass spectrometric binding studies involving estradiol-3,4-quinone or menadione with NQO1 clearly support the formation of an enzyme-substrate physical complex. However, the NQO1 mass spectrum did not alter after addition of cholesterol, the control. Two different strategies were employed to ascertain the NQO1 activity in estrogen quinone reduction. First, the ping-pong mechanism of NQO1 catalysis was utilized to overcome the problem of nonenzymatic reduction of the substrate by NADH. Second, tetrahydrofolic acid, which has a lower reducing potential, was used as an alternate cofactor. Both of these methods confirmed the reduction of estradiol-3,4-quinone by NQO1, when the assay mixtures were analyzed by UV or liquid chromatography-mass spectrometry. Furthermore, reduction of 9,10-phenanthrene quinone or menadione was observed using the reported assay conditions. Thus, clear evidence for the catalytic reduction of estrogen ortho-quinones by NQO1 has been obtained; its mechanism and implications are discussed.
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62
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Wondrak GT. NQO1-activated phenothiazinium redox cyclers for the targeted bioreductive induction of cancer cell apoptosis. Free Radic Biol Med 2007; 43:178-90. [PMID: 17603928 PMCID: PMC2705808 DOI: 10.1016/j.freeradbiomed.2007.03.035] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 03/21/2007] [Accepted: 03/30/2007] [Indexed: 11/24/2022]
Abstract
Altered redox signaling and regulation in cancer cells represent a chemical vulnerability that can be targeted by selective chemotherapeutic intervention. Here, we demonstrate that 3,7-diaminophenothiazinium-based redox cyclers (PRC) induce selective cancer cell apoptosis by NAD(P)H:quinone oxidoreductase (NQO1)-dependent bioreductive generation of cellular oxidative stress. Using PRC lead compounds including toluidine blue against human metastatic G361 melanoma cells, apoptosis occurred with phosphatidylserine externalization, loss of mitochondrial transmembrane potential, cytochrome c release, caspase-3 activation, and massive ROS production. Consistent with reductive activation and subsequent redox cycling as the mechanism of PRC cytotoxicity, coincubation with catalase achieved cell protection, whereas reductive antioxidants enhanced PRC cytotoxicity. Unexpectedly, human A375 melanoma cells were resistant to PRC-induced apoptosis, and PRC-sensitive G361 cells were protected by preincubation with the NQO1 inhibitor dicoumarol. Indeed, NQO1 specific enzymatic activity was 9-fold higher in G361 than in A375 cells. The critical role of NQO1 in PRC bioactivation and cytotoxicity was confirmed, when NQO1-transfected breast cancer cells (MCF7-DT15) stably overexpressing active NQO1 displayed strongly enhanced PRC sensitivity as compared to vector control-transfected cells with baseline NQO1 activity. Based on the known overexpression of NQO1 in various tumors these findings suggest the feasibility of developing PRC lead compounds into tumor-selective bioreductive chemotherapeutics.
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Affiliation(s)
- Georg T Wondrak
- Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724, USA.
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63
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64
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Blanco E, Bey EA, Dong Y, Weinberg BD, Sutton DM, Boothman DA, Gao J. Beta-lapachone-containing PEG-PLA polymer micelles as novel nanotherapeutics against NQO1-overexpressing tumor cells. J Control Release 2007; 122:365-74. [PMID: 17574288 PMCID: PMC2064869 DOI: 10.1016/j.jconrel.2007.04.014] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2007] [Revised: 04/13/2007] [Accepted: 04/19/2007] [Indexed: 12/18/2022]
Abstract
Beta-lapachone (beta-lap) is a novel anticancer agent that is bioactivated by NADP(H): quinone oxidoreductase 1 (NQO1), an enzyme overexpressed in a variety of tumors. Despite its therapeutic promise, the poor aqueous solubility of beta-lap hinders its preclinical evaluation and clinical translation. Our objective was to develop beta-lap-containing poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-PLA) polymer micelles for the treatment of NQO1-overexpressing tumors. Several micelle fabrication strategies were examined to maximize drug loading. A film sonication method yielded beta-lap micelles with relatively high loading density (4.7+/-1.0% to 6.5+/-1.0%) and optimal size (29.6+/-1.5 nm). Release studies in phosphate-buffered saline (pH 7.4) showed the time (t(1/2)) for 50% of drug release at 18 h. In vitro cytotoxicity assays were performed in NQO1-overexpressing (NQO1+) and NQO1-null (NQO1-) H596 lung, DU-145 prostate, and MDA-MB-231 breast cancer cells. Cytotoxicity data showed that after a 2 h incubation with beta-lap micelles, a marked increase in toxicity was shown in NQO1+ cells over NQO1- cells, resembling free drug both in efficacy and mechanism of cell death. In summary, these data demonstrate the potential of beta-lap micelles as an effective therapeutic strategy against NQO1-overexpressing tumor cells.
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Affiliation(s)
- Elvin Blanco
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, United States
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65
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Lu Y, Kham SKY, Foo TC, Ariffin H, Hany A, Quah TC, Yeoh AEJ. Genotyping of eight polymorphic genes encoding drug-metabolizing enzymes and transporters using a customized oligonucleotide array. Anal Biochem 2007; 360:105-13. [PMID: 17113562 DOI: 10.1016/j.ab.2006.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Revised: 10/03/2006] [Accepted: 10/03/2006] [Indexed: 11/17/2022]
Abstract
Polymorphisms in drug-metabolizing genes may lead to the production of dysfunctional proteins and consequently affect therapeutic efficacy and toxicity of drugs. Different frequencies of polymorphic alleles among the races have been postulated to account for the observed ethnic variations in drug responses. In the current study, we aimed to estimate the frequencies of 14 polymorphisms in eight genes (TPMT, NQO1, MTHFR, GSTP1, CYP1A1, CYP2D6, ABCB1, and SLC19A1) in the Singapore multiracial populations by screening 371 cord blood samples from healthy newborns. To improve genotyping efficacy, we designed an oligonucleotide array based on the principle of allele-specific primer extension (AsPEX) that was capable of detecting the 14 polymorphisms simultaneously. Cross-validation using conventional polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) assays demonstrated 99% concordant results. Measurements on the fluorescent intensity displayed clear distinctions among different genotypes. Statistical analyses showed significantly different allele distributions in several genes among the three races, namely Chinese, Malays, and Indians. Comparing the allelic frequencies in Chinese with previous studies in Caucasian populations, NQO1 609C>T and SLC19A1 80G>A were distinctly different, whereas close similarity was observed for MTHFR 677C>T. We have demonstrated an array-based methodology for rapid multiplex detection of genetic polymorphisms. The allelic frequencies reported in this study may have important therapeutic and prognostic implications in the clinical use of relevant drugs.
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Affiliation(s)
- Yi Lu
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074
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66
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Campeau LC, Fagnou K. Applications of and alternatives to π-electron-deficient azine organometallics in metal catalyzed cross-coupling reactions. Chem Soc Rev 2007; 36:1058-68. [PMID: 17576474 DOI: 10.1039/b616082d] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While the use of pi-deficient azine halides in palladium catalyzed cross-coupling reactions is common, the use of pi-electron deficient azine organometallics has been less intensively examined. In recent years, important advances have been made that are beginning to address this deficiency and need. The purpose of this tutorial review is to highlight and discuss the innovations that facilitate the synthesis of azine-containing biaryls with a focus on the pyridine structural motif. Given the number of important compounds which exhibit azine-heterobiaryls and the wide use of cross-coupling methods in their synthesis, this review should be of interest among synthetic organic chemists and organometallic chemists alike.
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Affiliation(s)
- Louis-Charles Campeau
- Center for Catalysis Research and Innovation, 10 Marie-Curie, Ottawa, Ontario, Canada
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Du J, Daniels DH, Asbury C, Venkataraman S, Liu J, Spitz DR, Oberley LW, Cullen JJ. Mitochondrial Production of Reactive Oxygen Species Mediate Dicumarol-induced Cytotoxicity in Cancer Cells. J Biol Chem 2006; 281:37416-26. [PMID: 17040906 DOI: 10.1074/jbc.m605063200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dicumarol is a naturally occurring anticoagulant derived from coumarin that induces cytotoxicity and oxidative stress in human pancreatic cancer cells (Cullen, J. J., Hinkhouse, M. M., Grady, M., Gaut, A. W., Liu, J., Zhang, Y., Weydert, C. J. D., Domann, F. E., and Oberley, L. W. (2003) Cancer Res. 63, 5513-5520). Although dicumarol has been used as an inhibitor of the two-electron reductase NAD(P)H:quinone oxidoreductase (NQO1), dicumarol is also thought to affect quinone-mediated electron transfer reactions in the mitochondria, leading to the production of superoxide (O2*-) and hydrogen peroxide (H(2)O(2)). We hypothesized that mitochondrial production of reactive oxygen species mediates the increased susceptibility of pancreatic cancer cells to dicumarol-induced metabolic oxidative stress. Dicumarol decreased clonogenic survival equally in both MDA-MB-468 NQO1(-) and MDA-MB-468 NQO1+ breast cancer cells. Dicumarol decreased clonogenic survival in the transformed fibroblast cell line IMRSV-90 compared with the IMR-90 cell line. Dicumarol, with the addition of mitochondrial electron transport chain blockers, decreased clonogenic cell survival in human pancreatic cancer cells and increased superoxide levels. Dicumarol with the mitochondrial electron transport chain blocker antimycin A decreased clonogenic survival and increased superoxide levels in cells with functional mitochondria but had little effect on cancer cells without functional mitochondria. Overexpression of manganese superoxide dismutase and mitochondrial-targeted catalase with adenoviral vectors reversed the dicumarol-induced cytotoxicity and reversed fluorescence of the oxidation-sensitive probe. We conclude mitochondrial production of reactive oxygen species mediates the increased susceptibility of cancer cells to dicumarol-induced cytotoxicity.
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Affiliation(s)
- Juan Du
- Department of Surgery and University of Iowa College of Medicine, Holden Comprehensive Cancer Center, and Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA
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