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Rabilloud T, Lescuyer P. Proteomics in mechanistic toxicology: History, concepts, achievements, caveats, and potential. Proteomics 2014; 15:1051-74. [DOI: 10.1002/pmic.201400288] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/25/2014] [Accepted: 08/25/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Thierry Rabilloud
- Laboratory of Chemistry and Biology of Metals; CNRS UMR; 5249 Grenoble France
- Laboratory of Chemistry and Biology of Metals; Université Grenoble Alpes; Grenoble France
- Laboratory of Chemistry and Biology of Metals; CEA Grenoble; iRTSV/CBM; Grenoble France
| | - Pierre Lescuyer
- Department of Human Protein Sciences; Clinical Proteomics and Chemistry Group; Geneva University; Geneva Switzerland
- Toxicology and Therapeutic Drug Monitoring Laboratory; Department of Genetic and Laboratory Medicine; Geneva University Hospitals; Geneva Switzerland
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202
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Tydén E, Tjälve H, Larsson P. Gene and protein expression and cellular localisation of cytochrome P450 enzymes of the 1A, 2A, 2C, 2D and 2E subfamilies in equine intestine and liver. Acta Vet Scand 2014; 56:69. [PMID: 25288196 PMCID: PMC4192735 DOI: 10.1186/s13028-014-0069-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 10/03/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Among the cytochrome P450 enzymes (CYP), families 1-3 constitute almost half of total CYPs in mammals and play a central role in metabolism of a wide range of pharmaceuticals. This study investigated gene and protein expression and cellular localisation of CYP1A, CYP2A, CYP2C, CYP2D and CYP2E in equine intestine and liver. Real-time polymerase chain reaction (RT-PCR) was used to analyse gene expression, western blot to examine protein expression and immunohistochemical analyses to investigate cellular localisation. RESULTS CYP1A and CYP2C were the CYPs with the highest gene expression in the intestine and also showed considerable gene expression in the liver. CYP2E and CYP2A showed the highest gene expression in the liver. CYP2E showed moderate intestinal gene expression, whereas that of CYP2A was very low or undetectable. For CYP2D, rather low gene expression levels were found in both intestine and the liver. In the intestine, CYP gene expression levels, except for CYP2E, exhibited patterns resembling those of the proteins, indicating that intestinal protein expression of these CYPs is regulated at the transcriptional level. For CYP2E, the results showed that the intestinal gene expression did not correlate to any visible protein expression, indicating that intestinal protein expression of this CYP is regulated at the post-transcriptional level. Immunostaining of intestine tissue samples showed preferential CYP staining in enterocytes at the tips of intestinal villi in the small intestine. In the liver, all CYPs showed preferential localisation in the centrilobular hepatocytes. CONCLUSIONS Overall, different gene expression profiles were displayed by the CYPs examined in equine intestine and liver. The CYPs present in the intestine may act in concert with those in the liver to affect the oral bioavailability and therapeutic efficiency of substrate drugs. In addition, they may play a role in first-pass metabolism of feed constituents and of herbal supplements used in equine practice.
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Affiliation(s)
- Eva Tydén
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
| | - Hans Tjälve
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
| | - Pia Larsson
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
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203
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Aravamudan B, Delmotte P, Thompson M, Vassallo R, Sieck GC, Pabelick CM, Prakash YS. Response to letter by Dr. Marc Hershenson (exposure of airway smooth muscle cells to cigarette smoke extract). Am J Physiol Lung Cell Mol Physiol 2014; 307:L346. [PMID: 25128539 DOI: 10.1152/ajplung.00194.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - Philippe Delmotte
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and
| | | | | | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | - Christina M Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and
| | - Y S Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and
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204
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Younus F, Chertemps T, Pearce SL, Pandey G, Bozzolan F, Coppin CW, Russell RJ, Maïbèche-Coisne M, Oakeshott JG. Identification of candidate odorant degrading gene/enzyme systems in the antennal transcriptome of Drosophila melanogaster. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 53:30-43. [PMID: 25038463 DOI: 10.1016/j.ibmb.2014.07.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 06/03/2023]
Abstract
The metabolism of volatile signal molecules by odorant degrading enzymes (ODEs) is crucial to the ongoing sensitivity and specificity of chemoreception in various insects, and a few specific esterases, cytochrome P450s, glutathione S-transferases (GSTs) and UDP-glycosyltransferases (UGTs) have previously been implicated in this process. Significant progress has been made in characterizing ODEs in Lepidoptera but very little is known about them in Diptera, including in Drosophila melanogaster, a major insect model. We have therefore carried out a transcriptomic analysis of the antennae of D. melanogaster in order to identify candidate ODEs. Virgin male and female and mated female antennal transcriptomes were determined by RNAseq. As with the Lepidoptera, we found that many esterases, cytochrome P450 enzymes, GSTs and UGTs are expressed in D. melanogaster antennae. As olfactory genes generally show selective expression in the antennae, a comparison to previously published transcriptomes for other tissues has been performed, showing preferential expression in the antennae for one esterase, JHEdup, one cytochrome P450, CYP308a1, and one GST, GSTE4. These largely uncharacterized enzymes are now prime candidates for ODE functions. JHEdup was expressed heterologously and found to have high catalytic activity against a chemically diverse group of known ester odorants for this species. This is a finding consistent with an ODE although it might suggest a general role in clearing several odorants rather than a specific role in clearing a particular odorant. Our findings do not preclude the possibility of odorant degrading functions for other antennally expressed esterases, P450s, GSTs and UGTs but, if so, they suggest that these enzymes also have additional functions in other tissues.
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Affiliation(s)
- Faisal Younus
- CSIRO Ecosystems Sciences, Black Mountain, Clunies Ross Street, Canberra, ACT 0200, Australia; Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Thomas Chertemps
- Université Pierre et Marie Curie, Institut d'Ecologie et des Sciences de l'Environnement de Paris, F-75252 Paris, France
| | - Stephen L Pearce
- CSIRO Ecosystems Sciences, Black Mountain, Clunies Ross Street, Canberra, ACT 0200, Australia; Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Gunjan Pandey
- CSIRO Ecosystems Sciences, Black Mountain, Clunies Ross Street, Canberra, ACT 0200, Australia
| | - Françoise Bozzolan
- Université Pierre et Marie Curie, Institut d'Ecologie et des Sciences de l'Environnement de Paris, F-75252 Paris, France
| | - Christopher W Coppin
- CSIRO Ecosystems Sciences, Black Mountain, Clunies Ross Street, Canberra, ACT 0200, Australia
| | - Robyn J Russell
- CSIRO Ecosystems Sciences, Black Mountain, Clunies Ross Street, Canberra, ACT 0200, Australia
| | - Martine Maïbèche-Coisne
- Université Pierre et Marie Curie, Institut d'Ecologie et des Sciences de l'Environnement de Paris, F-75252 Paris, France
| | - John G Oakeshott
- CSIRO Ecosystems Sciences, Black Mountain, Clunies Ross Street, Canberra, ACT 0200, Australia.
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205
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Brüning T, Bartsch R, Bolt HM, Desel H, Drexler H, Gundert-Remy U, Hartwig A, Jäckh R, Leibold E, Pallapies D, Rettenmeier AW, Schlüter G, Stropp G, Sucker K, Triebig G, Westphal G, van Thriel C. Sensory irritation as a basis for setting occupational exposure limits. Arch Toxicol 2014; 88:1855-79. [PMID: 25182421 PMCID: PMC4161939 DOI: 10.1007/s00204-014-1346-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/21/2014] [Indexed: 02/06/2023]
Abstract
There is a need of guidance on how local irritancy data should be incorporated into risk assessment procedures, particularly with respect to the derivation of occupational exposure limits (OELs). Therefore, a board of experts from German committees in charge of the derivation of OELs discussed the major challenges of this particular end point for regulatory toxicology. As a result, this overview deals with the question of integrating results of local toxicity at the eyes and the upper respiratory tract (URT). Part 1 describes the morphology and physiology of the relevant target sites, i.e., the outer eye, nasal cavity, and larynx/pharynx in humans. Special emphasis is placed on sensory innervation, species differences between humans and rodents, and possible effects of obnoxious odor in humans. Based on this physiological basis, Part 2 describes a conceptual model for the causation of adverse health effects at these targets that is composed of two pathways. The first, “sensory irritation” pathway is initiated by the interaction of local irritants with receptors of the nervous system (e.g., trigeminal nerve endings) and a downstream cascade of reflexes and defense mechanisms (e.g., eyeblinks, coughing). While the first stages of this pathway are thought to be completely reversible, high or prolonged exposure can lead to neurogenic inflammation and subsequently tissue damage. The second, “tissue irritation” pathway starts with the interaction of the local irritant with the epithelial cell layers of the eyes and the URT. Adaptive changes are the first response on that pathway followed by inflammation and irreversible damages. Regardless of these initial steps, at high concentrations and prolonged exposures, the two pathways converge to the adverse effect of morphologically and biochemically ascertainable changes. Experimental exposure studies with human volunteers provide the empirical basis for effects along the sensory irritation pathway and thus, “sensory NOAEChuman” can be derived. In contrast, inhalation studies with rodents investigate the second pathway that yields an “irritative NOAECanimal.” Usually the data for both pathways is not available and extrapolation across species is necessary. Part 3 comprises an empirical approach for the derivation of a default factor for interspecies differences. Therefore, from those substances under discussion in German scientific and regulatory bodies, 19 substances were identified known to be human irritants with available human and animal data. The evaluation started with three substances: ethyl acrylate, formaldehyde, and methyl methacrylate. For these substances, appropriate chronic animal and a controlled human exposure studies were available. The comparison of the sensory NOAEChuman with the irritative NOAECanimal (chronic) resulted in an interspecies extrapolation factor (iEF) of 3 for extrapolating animal data concerning local sensory irritating effects. The adequacy of this iEF was confirmed by its application to additional substances with lower data density (acetaldehyde, ammonia, n-butyl acetate, hydrogen sulfide, and 2-ethylhexanol). Thus, extrapolating from animal studies, an iEF of 3 should be applied for local sensory irritants without reliable human data, unless individual data argue for a substance-specific approach.
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Affiliation(s)
- Thomas Brüning
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Bochum, Germany,
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206
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Expression profiles of genes involved in xenobiotic metabolism and disposition in human renal tissues and renal cell models. Toxicol Appl Pharmacol 2014; 279:409-418. [DOI: 10.1016/j.taap.2014.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 06/17/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022]
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207
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Ahlawat S, Xie F, Zhu Y, D'Hondt R, Ding X, Zhang QY, Mantis NJ. Mice deficient in intestinal epithelium cytochrome P450 reductase are prone to acute toxin-induced mucosal damage. Sci Rep 2014; 4:5551. [PMID: 24989705 PMCID: PMC4080431 DOI: 10.1038/srep05551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/11/2014] [Indexed: 12/19/2022] Open
Abstract
Cytochrome P450 (P450) enzymes are a superfamily of heme-containing enzymes involved in the metabolism of various endogenous compounds, including retinoids, glucocorticoids, and eicosanoids, that are postulated to participate in the maintenance and/or development of inflammatory and immune reactions in the intestinal mucosa. To investigate the role of P450 enzymes in intestinal inflammation and immunity, we took advantage of IE-Cpr-null mice, which are deficient in intestinal epithelium of NADPH-cytochrome P450 reductase (CPR), the obligate redox partner of all microsomal P450 enzymes. We report that IE-Cpr-null mice, following an acute toxin challenge, had higher levels of pro-inflammatory chemokines and increased tissue damage compared to wild-type mice. IE-Cpr-null mice had normal Peyer's patch numbers and elicited normal secretory IgA (SIgA) responses. However, SIgA baseline levels in IE-Cpr-null mice were consistently elevated over WT littermates. While neither retinoic acid nor glucocorticoid levels in serum and intestinal homogenates were altered in IE-Cpr-null mice, basal levels of arachidonic acid metabolites (11,12-DiHETE and 14,15-DiHETE) with known anti-inflammatory property were significantly lower compared to WT controls. Overall, these findings reveal immunological and metabolic changes resulting from a genetic deficiency in CPR expression in the intestine, and support a role for microsomal P450 enzymes in mucosal homeostasis and immunity.
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Affiliation(s)
- Sarita Ahlawat
- 1] Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY [2]
| | - Fang Xie
- 1] Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, NY [2]
| | - Yi Zhu
- 1] Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, NY [2] Departments of Environmental Health Sciences, University at Albany, Albany, NY 12208
| | - Rebecca D'Hondt
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY
| | - Xinxin Ding
- 1] Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, NY [2] Departments of Environmental Health Sciences, University at Albany, Albany, NY 12208 [3] Biomedical Sciences, University at Albany, Albany, NY 12208
| | - Qing-Yu Zhang
- 1] Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, NY [2] Departments of Environmental Health Sciences, University at Albany, Albany, NY 12208
| | - Nicholas J Mantis
- 1] Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY [2] Biomedical Sciences, University at Albany, Albany, NY 12208
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208
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Qualitative de novo analysis of full length cDNA and quantitative analysis of gene expression for common marmoset (Callithrix jacchus) transcriptomes using parallel long-read technology and short-read sequencing. PLoS One 2014; 9:e100936. [PMID: 24977701 PMCID: PMC4076266 DOI: 10.1371/journal.pone.0100936] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/28/2014] [Indexed: 12/24/2022] Open
Abstract
The common marmoset (Callithrix jacchus) is a non-human primate that could prove useful as human pharmacokinetic and biomedical research models. The cytochromes P450 (P450s) are a superfamily of enzymes that have critical roles in drug metabolism and disposition via monooxygenation of a broad range of xenobiotics; however, information on some marmoset P450s is currently limited. Therefore, identification and quantitative analysis of tissue-specific mRNA transcripts, including those of P450s and flavin-containing monooxygenases (FMO, another monooxygenase family), need to be carried out in detail before the marmoset can be used as an animal model in drug development. De novo assembly and expression analysis of marmoset transcripts were conducted with pooled liver, intestine, kidney, and brain samples from three male and three female marmosets. After unique sequences were automatically aligned by assembling software, the mean contig length was 718 bp (with a standard deviation of 457 bp) among a total of 47,883 transcripts. Approximately 30% of the total transcripts were matched to known marmoset sequences. Gene expression in 18 marmoset P450- and 4 FMO-like genes displayed some tissue-specific patterns. Of these, the three most highly expressed in marmoset liver were P450 2D-, 2E-, and 3A-like genes. In extrahepatic tissues, including brain, gene expressions of these monooxygenases were lower than those in liver, although P450 3A4 (previously P450 3A21) in intestine and P450 4A11- and FMO1-like genes in kidney were relatively highly expressed. By means of massive parallel long-read sequencing and short-read technology applied to marmoset liver, intestine, kidney, and brain, the combined next-generation sequencing analyses reported here were able to identify novel marmoset drug-metabolizing P450 transcripts that have until now been little reported. These results provide a foundation for mechanistic studies and pave the way for the use of marmosets as model animals for drug development in the future.
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209
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Somboon T, Ochiai J, Treesuwan W, Gleeson MP, Hannongbua S, Mori S. Mechanistic insights into the catalytic reaction of plant allene oxide synthase (pAOS) via QM and QM/MM calculations. J Mol Graph Model 2014; 52:20-9. [PMID: 24984079 DOI: 10.1016/j.jmgm.2014.05.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 11/26/2022]
Abstract
QM cluster and QM/MM protein models have been employed to understand aspects of the reaction mechanism of plant allene oxide synthase (pAOS). In this study we have investigated two reaction mechanisms for pAOS. The standard pAOS mechanism was contrasted with an alternative involving an additional active site molecule which has been shown to facilitate proton coupled electron transfer (PCET) in related systems. Firstly, we found that the results from QM/MM protein model are comparable with those from the QM cluster model, presumably due to the large active site used. Furthermore, the results from the QM cluster model show that the Fe(III) and Fe(IV) pathways for the standard mechanism have similar energetic and structural properties, indicating that the reaction mechanism may well proceed via both pathways. However, while the PCET process is facilitated by an additional active site bound water in other related families, in pAOS it is not, suggesting this type of process is not general to all closely related family members.
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Affiliation(s)
- Tuanjai Somboon
- Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
| | - Jun Ochiai
- Faculty of Science, Ibaraki University, Ibaraki 310-8512, Japan
| | - Witcha Treesuwan
- Institute of Food Research and Product Development, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
| | - M Paul Gleeson
- Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
| | - Supa Hannongbua
- Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand; Center of Nanotechnology KU, Kasetsart University, Chatuchak, Bangkok 10900 Thailand.
| | - Seiji Mori
- Faculty of Science, Ibaraki University, Ibaraki 310-8512, Japan; Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Ibaraki 319-1106, Japan.
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210
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Berg T, Hegelund Myrbäck T, Olsson M, Seidegård J, Werkström V, Zhou XH, Grunewald J, Gustavsson L, Nord M. Gene expression analysis of membrane transporters and drug-metabolizing enzymes in the lung of healthy and COPD subjects. Pharmacol Res Perspect 2014; 2:e00054. [PMID: 25505599 PMCID: PMC4186441 DOI: 10.1002/prp2.54] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 04/24/2014] [Accepted: 05/02/2014] [Indexed: 01/06/2023] Open
Abstract
This study describes for the first time the expression levels of genes encoding membrane transporters and drug-metabolizing enzymes in the lungs of ex-smoking patients with chronic obstructive pulmonary disease (COPD). Membrane transporters and drug-metabolizing enzymes are key determinants of drug uptake, metabolism, and elimination for systemically administered as well as inhaled drugs, with consequent influence on clinical efficacy and patient safety. In this study, while no difference in gene expression was found between healthy and COPD subjects, we identified a significant regional difference in mRNA expression of both membrane transporters and drug-metabolizing enzymes between central and peripheral tissue in both healthy and COPD subjects. The majority of the differentially expressed genes were higher expressed in the central airways such as the transporters SLC2A1 (GLUT1), SLC28A3 (CNT3), and SLC22A4 (OCTN1) and the drug-metabolizing enzymes GSTZ1, GSTO2, and CYP2F1. Together, this increased knowledge of local pharmacokinetics in diseased and normal lung may improve modeling of clinical outcomes of new chemical entities intended for inhalation therapy delivered to COPD patients. In addition, based on the similarities between COPD and healthy subjects regarding gene expression of membrane transporters and drug-metabolizing enzymes, our results suggest that clinical pharmacological studies in healthy volunteers could be a valid model of COPD patients regarding drug disposition of inhaled drugs in terms of drug metabolism and drug transporters.
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Affiliation(s)
- Tove Berg
- Respiratory Medicine Unit, Department of Medicine Solna and CMM, Karolinska Institutet and Karolinska University Hospital Solna Stockholm, Sweden
| | | | | | | | | | | | - Johan Grunewald
- Respiratory Medicine Unit, Department of Medicine Solna and CMM, Karolinska Institutet and Karolinska University Hospital Solna Stockholm, Sweden
| | - Lena Gustavsson
- Molecular Medicine, Department of Laboratory Medicine, Lund University Medicon Village, Lund, Sweden
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211
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Valencia-Olvera AC, Morán J, Camacho-Carranza R, Prospéro-García O, Espinosa-Aguirre JJ. CYP2E1 induction leads to oxidative stress and cytotoxicity in glutathione-depleted cerebellar granule neurons. Toxicol In Vitro 2014; 28:1206-14. [PMID: 24929095 DOI: 10.1016/j.tiv.2014.05.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/25/2014] [Accepted: 05/30/2014] [Indexed: 11/27/2022]
Abstract
Increasing evidence suggests that brain cytochrome P450 (CYP) can contribute to the in situ metabolism of xenobiotics. In the liver, some xenobiotics can be metabolized by CYPs into more reactive products that can damage hepatocytes and induce cell death. In addition, normal CYP activity may produce reactive oxygen species (ROS) that contribute to cell damage through oxidative mechanisms. CYP2E1 is a CYP isoform that can generate ROS leading to cytotoxicity in multiple tissue types. The aim of this study was to determine whether CYP2E1 induction may lead to significant brain cell impairment. Immunological analysis revealed that exposure of primary cerebellar granule neuronal cultures to the CYP inducer isoniazid, increased CYP2E1 expression. In the presence of buthionine sulfoximine, an agent that reduces glutathione levels, isoniazid treatment also resulted in reactive oxygen species (ROS) production, DNA oxidation and cell death. These effects were attenuated by simultaneous exposure to diallyl sulfide, a CYP2E1 inhibitor, or to a mimetic of superoxide dismutase/catalase, (Euka). These results suggest that in cases of reduced antioxidant levels, the induction of brain CYP2E1 could represent a risk of in situ neuronal damage.
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Affiliation(s)
- Ana Carolina Valencia-Olvera
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, D.F., Mexico
| | - Julio Morán
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, D.F., Mexico
| | - Rafael Camacho-Carranza
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, D.F., Mexico
| | - Oscar Prospéro-García
- Grupo de Neurociencias, Laboratorio de Canabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, DF, Mexico
| | - Jesús Javier Espinosa-Aguirre
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, D.F., Mexico.
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212
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Jia K, Li L, Liu Z, Hartog M, Kluetzman K, Zhang QY, Ding X. Generation and characterization of a novel CYP2A13--transgenic mouse model. Drug Metab Dispos 2014; 42:1341-8. [PMID: 24907355 DOI: 10.1124/dmd.114.059188] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP2A13, CYP2B6, and CYP2F1 are neighboring cytochrome P450 genes on human chromosome 19, and the enzymes that they encode overlap in substrate specificity. A CYP2A13/2B6/2F1-transgenic mouse, in which CYP2A13 and 2F1 are both expressed in the respiratory tract and CYP2B6 is expressed in the liver, was recently generated. We generated a CYP2A13 (only) transgenic mouse so that the specific activity of CYP2A13 can be determined. The CYP2B6 and CYP2F1 genes in the CYP2A13/2B6/2F1 genomic clone were inactivated via genetic manipulations, and CYP2A13 was kept intact. A CYP2A13 (only) transgenic (2A13-TG) mouse was generated using the engineered construct and then characterized to confirm transgene integrity and determine copy numbers. The 2A13-TG mice were normal in gross morphology, development, and fertility. As in the CYP2A13/2B6/2F1-transgenic mouse, CYP2A13 expression in the 2A13-TG mouse was limited to the respiratory tract; in contrast, CYP2B6 and 2F1 proteins were not detected. Additional studies using the CYP2A13-humanized (2A13-TG/Cyp2abfgs-null) mouse produced by intercrossing between 2A13-TG and Cyp2abfgs-null mice confirmed that the transgenic CYP2A13 is active in the bioactivation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a lung procarcinogen. The 2A13-TG mouse should be valuable for assessing specific roles of human CYP2A13 in xenobiotic toxicity in the respiratory tract.
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Affiliation(s)
- Kunzhi Jia
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
| | - Lei Li
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
| | - Zhihua Liu
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
| | - Matthew Hartog
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
| | - Kerri Kluetzman
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
| | - Qing-Yu Zhang
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
| | - Xinxin Ding
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York
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213
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Linares OA, Schiesser WE, Linares AD, Stefanovski D, Boston RC. A Transit Compartment Model Unmasks OxyContin's Reflective Pharmacokinetics From Urine Measurements in Humans. J Pain Palliat Care Pharmacother 2014; 28:96-108. [DOI: 10.3109/15360288.2014.908991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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214
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Liu FF, Escher BI, Were S, Duffy L, Ng JC. Mixture Effects of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) on Lung Carcinoma Cells via a Hanging Drop Air Exposure System. Chem Res Toxicol 2014; 27:952-9. [DOI: 10.1021/tx5000552] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Faye F. Liu
- National
Research Centre for Environmental Toxicology (Entox), The University of Queensland, 39 Kessels Road, Coopers Plains, Brisbane, Queensland 4108, Australia
- CRC for Contamination Assessment and Remediation of the Environment, Mawson Lakes, Adelaide, South Australia 5095, Australia
| | - Beate I. Escher
- National
Research Centre for Environmental Toxicology (Entox), The University of Queensland, 39 Kessels Road, Coopers Plains, Brisbane, Queensland 4108, Australia
| | - Stephen Were
- Department
of Agriculture, Fisheries and Forestry, Queensland, Health and Food Sciences Precinct (DAFF), 39 Kessels Road, Brisbane, Queensland 4108, Australia
| | - Lesley Duffy
- CSIRO Food and Nutritional Sciences, 39 Kessels Road, Coopers Plains, Brisbane, Queensland 4108, Australia
| | - Jack C. Ng
- National
Research Centre for Environmental Toxicology (Entox), The University of Queensland, 39 Kessels Road, Coopers Plains, Brisbane, Queensland 4108, Australia
- CRC for Contamination Assessment and Remediation of the Environment, Mawson Lakes, Adelaide, South Australia 5095, Australia
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215
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MAIER-SALAMON ALEXANDRA, THALHAMMER THERESIA, REZNICEK GOTTFRIED, BÖHMDORFER MICHAELA, ZUPKÓ ISTVÁN, HARTL ALEXANDER, JAEGER WALTER. Cytochrome P450 3A-mediated metabolism of the topoisomerase I inhibitor 9-aminocamptothecin: Ιmpact on cancer therapy. Int J Oncol 2014; 45:877-86. [DOI: 10.3892/ijo.2014.2473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/02/2014] [Indexed: 11/05/2022] Open
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216
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Linares OA, Daly D, Linares AD, Stefanovski D, Boston RC. Personalized Oxycodone Dosing: Using Pharmacogenetic Testing and Clinical Pharmacokinetics to Reduce Toxicity Risk and Increase Effectiveness. PAIN MEDICINE 2014; 15:791-806. [DOI: 10.1111/pme.12380] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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217
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Differential expression of cytochrome P450 enzymes in normal and tumor tissues from childhood rhabdomyosarcoma. PLoS One 2014; 9:e93261. [PMID: 24699256 PMCID: PMC3974704 DOI: 10.1371/journal.pone.0093261] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/02/2014] [Indexed: 12/11/2022] Open
Abstract
Intratumoral expression of genes encoding Cytochrome P450 enzymes (CYP) might play a critical role not only in cancer development but also in the metabolism of anticancer drugs. The purpose of this study was to compare the mRNA expression patterns of seven representative CYPs in paired tumor and normal tissue of child patients with rabdomyosarcoma (RMS). Using real time quantitative RT-PCR, the gene expression pattern of CYP1A1, CYP1A2, CYP1B1, CYP2E1, CYP2W1, CYP3A4, and CYP3A5 were analyzed in tumor and adjacent non-tumor tissues from 13 child RMS patients. Protein concentration of CYPs was determined using Western blot. The expression levels were tested for correlation with the clinical and pathological data of the patients. Our data showed that the expression levels of CYP1A1 and CYP1A2 were negligible. Elevated expression of CYP1B1 mRNA and protein was detected in most RMS tumors and adjacent normal tissues. Most cancerous samples exhibit higher levels of both CYP3A4 and CYP3A5 compared with normal tissue samples. Expression of CYP2E1 mRNA was found to be significantly higher in tumor tissue, however no relation was found with protein levels. CYP2W1 mRNA and/or protein are mainly expressed in tumors. In conclusion, we defined the CYP gene expression profile in tumor and paired normal tissue of child patients with RMS. The overexpression of CYP2W1, CYP3A4 and CYP3A5 in tumor tissues suggests that they may be involved in RMS chemoresistance; furthermore, they may be exploited for the localized activation of anticancer prodrugs.
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218
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Ikemura K, Iwamoto T, Okuda M. MicroRNAs as regulators of drug transporters, drug-metabolizing enzymes, and tight junctions: implication for intestinal barrier function. Pharmacol Ther 2014; 143:217-24. [PMID: 24631272 DOI: 10.1016/j.pharmthera.2014.03.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 02/28/2014] [Indexed: 12/16/2022]
Abstract
Drug transporters, drug-metabolizing enzymes, and tight junctions in the small intestine function as an absorption barrier and sometimes as a facilitator of orally administered drugs. The expression of these proteins often fluctuates and thereby causes individual pharmacokinetic variability. MicroRNAs (miRNAs), which are small non-coding RNAs, have recently emerged as a new class of gene regulator. MiRNAs post-transcriptionally regulate gene expression by binding to target mRNA to suppress its translation or regulate its degradation. They have been shown to be key regulators of proteins associated with pharmacokinetics. Moreover, the role of miRNAs on the expression of some proteins expressed in the small intestine has recently been clarified. In this review, we summarize current knowledge regarding the role of miRNAs in the regulation of drug transporters, drug-metabolizing enzymes, and tight junctions as well as its implication for intestinal barrier function. MiRNAs play vital roles in the differentiation, architecture, and barrier function of intestinal epithelial cells, and directly and/or indirectly regulate the expression and function of proteins associated with drug absorption in intestinal epithelial cells. Moreover, the variation of miRNA expression caused by pathological and physiological conditions as well as genetic factors should affect the expression of these proteins. Therefore, miRNAs could be significant factors affecting inter- and intra-individual variations in the pharmacokinetics and intestinal absorption of drugs. Overall, miRNAs could be promising targets for personalized pharmacotherapy or other attractive therapies through intestinal absorption of drugs.
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Affiliation(s)
- Kenji Ikemura
- Department of Pharmacy, Mie University Hospital, Tsu, Mie 514-8507, Japan
| | - Takuya Iwamoto
- Department of Pharmacy, Mie University Hospital, Tsu, Mie 514-8507, Japan; Department of Clinical Pharmacy and Biopharmaceutics, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
| | - Masahiro Okuda
- Department of Pharmacy, Mie University Hospital, Tsu, Mie 514-8507, Japan; Department of Clinical Pharmacy and Biopharmaceutics, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
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219
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Megaraj V, Ding X, Fang C, Kovalchuk N, Zhu Y, Zhang QY. Role of hepatic and intestinal p450 enzymes in the metabolic activation of the colon carcinogen azoxymethane in mice. Chem Res Toxicol 2014; 27:656-62. [PMID: 24552495 PMCID: PMC4002058 DOI: 10.1021/tx4004769] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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P450-mediated
bioactivation of azoxymethane (AOM), a colon carcinogen,
leads to the formation of DNA adducts, of which O6-methylguanine (O6-mG) is the most mutagenic
and contributes to colon tumorigenesis. To determine whether P450
enzymes of the liver and intestine both contribute to AOM bioactivation in vivo, we compared tissue levels of AOM-induced DNA adducts,
microsomal AOM metabolic activities, and incidences of colonic aberrant
crypt foci (ACF) among wild-type (WT), liver-specific P450 reductase
(Cpr)-null (LCN), and intestinal epithelium-specific Cpr-null (IECN)
mice. At 6 h following AOM treatment (at 14 mg/kg, s.c.), O6-mG and N7-mG levels were highest in the liver, followed
by the colon, and then small intestine in WT mice. As expected, hepatic
adduct levels were significantly lower (by >60%) in LCN mice but
unchanged
in IECN mice, whereas small-intestinal adduct levels were unchanged
or increased in LCN mice but lower (by >50%) in IECN mice compared
to that in WT mice. However, colonic adduct levels were unchanged
in IECN mice compared to that in WT mice and increased in LCN mice
(by 1.5–2.9-fold). The tissue-specific impact of the CPR loss
in IECN and LCN mice on microsomal AOM metabolic activity was confirmed
by rates of formation of formaldehyde and N7-mG in vitro. Furthermore, the incidence of ACF, a lesion preceding
colon cancer, was similar in the three mouse strains. Thus, AOM-induced
colonic DNA damage and ACF formation is not solely dependent on either
hepatic or intestinal microsomal P450 enzymes. P450 enzymes in both
the liver and intestine likely contribute to AOM-induced colon carcinogenesis.
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Affiliation(s)
- Vandana Megaraj
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany , Albany, New York 12201, United States
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220
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Hersman EM, Bumpus NN. A targeted proteomics approach for profiling murine cytochrome P450 expression. J Pharmacol Exp Ther 2014; 349:221-8. [PMID: 24594750 DOI: 10.1124/jpet.113.212456] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The cytochrome P450 (P450) superfamily of enzymes plays a prominent role in drug metabolism. Although mice are a widely used preclinical model in pharmacology, the expression of murine P450 enzymes at the protein level has yet to be fully defined. Twenty-seven proteins belonging to P450 subfamilies 1A, 2A, 2B, 2C, 2D, 2E, 2F, 2J, 2U, 3A, 4A, 4B, 4F, and 4V were readily detectable in Balb/c mouse tissue using a global mass spectrometry-based proteomics approach. Subsequently, a targeted mass spectrometry-based assay was developed to simultaneously quantify these enzymes in ranges of femtomoles of P450 per microgram of total protein concentration range. This screen was applied to mouse liver microsomes and tissue lysates of kidney, lung, intestine, heart, and brain isolated from mixed-sex fetuses; male and female mice that were 3-4 weeks, 9-10 weeks, and 8-10 months of age; and pregnant mice. CYP1A2 was consistently more abundant in male mouse liver microsomes compared with age-matched females. Hepatic expression of CYP2B9 was more abundant in 3- to 4-week-old male and female mice than in mice of other ages; in addition, CYP2B9 was the only enzyme that was detectable at higher levels in pregnant mouse liver microsomes compared with age-matched females. Interestingly, sexually dimorphic expression of CYP2B9, 2D26, 2E1, and 4B1 was observed in kidney only. The targeted proteomics assay described here can be broadly used as a tool for investigating the expression patterns of P450 enzymes in mice.
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Affiliation(s)
- Elisabeth M Hersman
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
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221
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Gagnaire F, Boucard S. Olfactory mucosal necrosis in rats following acute intraperitoneal administration of 1,2-diethylbenzene, 1,2-diacetylbenzene and 2,5-hexanedione. Neurotoxicology 2014; 41:9-19. [DOI: 10.1016/j.neuro.2013.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/17/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
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222
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Badal S, Delgoda R. Role of the modulation of CYP1A1 expression and activity in chemoprevention. J Appl Toxicol 2014; 34:743-53. [PMID: 24532440 DOI: 10.1002/jat.2968] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/06/2013] [Accepted: 11/06/2013] [Indexed: 12/11/2022]
Affiliation(s)
- S. Badal
- Natural Products Institute, Faculty of Science and Technology; University of the West Indies; Mona Kingston 7 Jamaica, West Indies
| | - R. Delgoda
- Natural Products Institute, Faculty of Science and Technology; University of the West Indies; Mona Kingston 7 Jamaica, West Indies
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223
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Hernandez-Ramon EE, Sandoval NA, John K, Cline JM, Wood CE, Woodward RA, Poirier MC. Tamoxifen-DNA adduct formation in monkey and human reproductive organs. Carcinogenesis 2014; 35:1172-6. [PMID: 24501327 DOI: 10.1093/carcin/bgu029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The estrogen analog tamoxifen (TAM), used for adjuvant therapy of breast cancer, induces endometrial and uterine tumors in breast cancer patients. Proliferation stimulus of the uterine endometrium is likely involved in tumor induction, but genotoxicity may also play a role. Formation of TAM-DNA adducts in human tissues has been reported but remains controversial. To address this issue, we examined TAM-DNA adducts in uteri from two species of monkeys, Erythrocebus patas (patas) and Macaca fascicularis (macaque), and in human endometrium and myometrium. Monkeys were given 3-4 months of chronic TAM dosing scaled to be equivalent to the daily human dose. In the uteri, livers and brains from the patas (n = 3), and endometrium from the macaques (n = 4), TAM-DNA adducts were measurable by TAM-DNA chemiluminescence immunoassay. Average TAM-DNA adduct values for the patas uteri (23 adducts/10(8) nucleotides) were similar to those found in endometrium of the macaques (19 adducts/10(8) nucleotides). Endometrium of macaques exposed to both TAM and low-dose estradiol (n = 5) averaged 34 adducts/10(8) nucleotides. To examine TAM-DNA persistence in the patas, females (n = 3) were exposed to TAM for 3 months and to no drug for an additional month, resulting in low or non-detectable TAM-DNA in livers and uteri. Human endometrial and myometrial samples from women receiving (n = 8) and not receiving (n = 8) TAM therapy were also evaluated. Women receiving TAM therapy averaged 10.3 TAM-DNA adducts/10(8) nucleotides, whereas unexposed women showed no detectable TAM-DNA. The data indicate that genotoxicity, in addition to estrogen agonist effects, may contribute to TAM-induced human endometrial cancer.
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Affiliation(s)
- Elena E Hernandez-Ramon
- Carcinogen-DNA Interactions Section, LCBG, CCR, National Cancer Institute, NIH, Building 37, Room 4032, NIH 37 Convent Drive, MSC-4255, Bethesda, MD 20892, USA
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224
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Xu M, Ju W, Hao H, Wang G, Li P. Cytochrome P450 2J2: distribution, function, regulation, genetic polymorphisms and clinical significance. Drug Metab Rev 2014; 45:311-52. [PMID: 23865864 DOI: 10.3109/03602532.2013.806537] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cytochrome P450 2J2 (CYP2J2) is an enzyme mainly found in human extrahepatic tissues, with predominant expression in the cardiovascular systems and lower levels in the intestine, kidney, lung, pancreas, brain, liver, etc. During the past 15 years, CYP2J2 has attracted much attention for its epoxygenase activity in arachidonic acid (AA) metabolism. It converts AA to four epoxyeicosatrienoic acids (EETs) that have various biological effects, especially in the cardiovascular systems. In recent publications, CYP2J2 is shown highly expressed in various human tumor cells, and its EET metabolites are demonstrated to implicate in the pathologic development of human cancers. CYP2J2 is also a human CYP that involved in phase I xenobiotics metabolism. Antihistamine drugs and many other compounds were identified as the substrates of CYP2J2, and studies have demonstrated that these substrates have a broad structural diversity. CYP2J2 is found not readily induced by known P450 inducers; however, its expression could be regulated in some pathological conditions, might through the activator protein-1(AP-1), the AP-1-like element and microRNA let-7b. Several genetic mutations in the CYP2J2 gene have been identified in humans, and some of them have been shown to have potential associations with some diseases. With the increasing awareness of its roles in cancer disease and drug metabolism, studies about CYP2J2 are still going on, and various inhibitors of CYP2J2 have been determined. Further studies are needed to delineate the roles of CYP2J2 in disease pathology, drug development and clinical practice.
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Affiliation(s)
- Meijuan Xu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
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225
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Wang HJ, Pao LH, Hsiong CH, Shih TY, Lee MS, Hu OYP. Dietary flavonoids modulate CYP2C to improve drug oral bioavailability and their qualitative/quantitative structure-activity relationship. AAPS JOURNAL 2014; 16:258-68. [PMID: 24431079 DOI: 10.1208/s12248-013-9549-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 11/18/2013] [Indexed: 01/10/2023]
Abstract
This study aims to improve the drug oral bioavailability by co-administration with flavonoid inhibitors of the CYP2C isozyme and to establish qualitative and quantitative (QSAR) structure-activity relationships (SAR) between flavonoids and CYP2C. A total of 40 naturally occurring flavonoids were screened in vitro for CYP2C inhibition. Enzyme activity was determined by measuring conversion of tolbutamide to 4-hydroxytolbutamide by rat liver microsomes. The percent inhibition and IC50 of each flavonoid were calculated and used to develop SAR and QSAR. The most effective flavonoid was orally co-administered in vivo with a cholesterol-reducing drug, fluvastatin, which is normally metabolized by CYP2C. The most potent CYP2C inhibitor identified in vitro was tamarixetin (IC50 = 1.4 μM). This flavonoid enhanced the oral bioavailability of fluvastatin in vivo, producing a >2-fold increase in the area under the concentration-time curve and in the peak plasma concentration. SAR analysis indicated that the presence of a 2,3-double bond in the C ring, hydroxylation at positions 5, 6, and 7, and glycosylation had important effects on flavonoid-CYP2C interactions. These findings should prove useful for predicting the inhibition of CYP2C activity by other untested flavonoid-like compounds. In the present study, tamarixetin significantly inhibited CYP2C activity in vitro and in vivo. Thus, the use of tamarixetin could improve the therapeutic efficacy of drugs with low bioavailability.
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Affiliation(s)
- Hong-Jaan Wang
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
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226
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Mazzarino M, de la Torre X, Fiacco I, Palermo A, Botrè F. Drug-drug interaction and doping, part 1: Anin vitrostudy on the effect of non-prohibited drugs on the phase I metabolic profile of toremifene. Drug Test Anal 2014; 6:482-91. [DOI: 10.1002/dta.1592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 11/08/2013] [Accepted: 11/12/2013] [Indexed: 01/13/2023]
Affiliation(s)
- Monica Mazzarino
- Laboratorio Antidoping; Federazione Medico Sportiva Italiana; Largo Giulio Onesti, 1 00197 Rome Italy
| | - Xavier de la Torre
- Laboratorio Antidoping; Federazione Medico Sportiva Italiana; Largo Giulio Onesti, 1 00197 Rome Italy
| | - Ilaria Fiacco
- Laboratorio Antidoping; Federazione Medico Sportiva Italiana; Largo Giulio Onesti, 1 00197 Rome Italy
| | - Amelia Palermo
- Laboratorio Antidoping; Federazione Medico Sportiva Italiana; Largo Giulio Onesti, 1 00197 Rome Italy
| | - Francesco Botrè
- Laboratorio Antidoping; Federazione Medico Sportiva Italiana; Largo Giulio Onesti, 1 00197 Rome Italy
- Dipartimento di Medicina Sperimentale; “Sapienza” Università di Roma; Viale Regina Elena 324 00161 Rome Italy
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227
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de Lacy Costello B, Amann A, Al-Kateb H, Flynn C, Filipiak W, Khalid T, Osborne D, Ratcliffe NM. A review of the volatiles from the healthy human body. J Breath Res 2014; 8:014001. [PMID: 24421258 DOI: 10.1088/1752-7155/8/1/014001] [Citation(s) in RCA: 511] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A compendium of all the volatile organic compounds (VOCs) emanating from the human body (the volatolome) is for the first time reported. 1840 VOCs have been assigned from breath (872), saliva (359), blood (154), milk (256), skin secretions (532) urine (279), and faeces (381) in apparently healthy individuals. Compounds were assigned CAS registry numbers and named according to a common convention where possible. The compounds have been grouped into tables according to their chemical class or functionality to permit easy comparison. Some clear differences are observed, for instance, a lack of esters in urine with a high number in faeces. Careful use of the database is needed. The numbers may not be a true reflection of the actual VOCs present from each bodily excretion. The lack of a compound could be due to the techniques used or reflect the intensity of effort e.g. there are few publications on VOCs from blood compared to a large number on VOCs in breath. The large number of volatiles reported from skin is partly due to the methodologies used, e.g. collecting excretions on glass beads and then heating to desorb VOCs. All compounds have been included as reported (unless there was a clear discrepancy between name and chemical structure), but there may be some mistaken assignations arising from the original publications, particularly for isomers. It is the authors' intention that this database will not only be a useful database of VOCs listed in the literature, but will stimulate further study of VOCs from healthy individuals. Establishing a list of volatiles emanating from healthy individuals and increased understanding of VOC metabolic pathways is an important step for differentiating between diseases using VOCs.
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Affiliation(s)
- B de Lacy Costello
- Institute of Biosensor Technology, University of the West of England, Bristol BS16 1QY, UK
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228
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Plewka D, Plewka A, Szczepanik T, Morek M, Bogunia E, Wittek P, Kijonka C. Expression of selected cytochrome P450 isoforms and of cooperating enzymes in colorectal tissues in selected pathological conditions. Pathol Res Pract 2014; 210:242-9. [PMID: 24485758 DOI: 10.1016/j.prp.2013.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 10/20/2013] [Accepted: 12/16/2013] [Indexed: 01/28/2023]
Abstract
The current interest in CYP expression in the colon results from its uniqueness as a target organ for cancer. To date, the CYP expression profiles in the colon have not yet been subject of comprehensive research. In this study, we investigated 40 patients with Crohn's disease, 40 with ulcerative colitis, and 40 healthy subjects as a control group. Colon tissues were fixed, dehydrated, cleared in xylene and embedded in paraffin. Sections were prepared from paraffin blocks for immunohistochemical staining with specific antibodies. We used antibodies to the human CYP1A1, CYP2B6, CYP2C9, CYP2E1 and CYP3A4 isoforms, as well as antibodies to the human glycoprotein P, glutathione-S transferase and antibody to the UDP-glucuronosyltransferase. The sections were stained immunohistochemically and examined using light microscopy. Cellular localization was determined, and computer image analysis was used. In all cases with Crohn's disease, the proteins studied showed at least a twofold expression. Ulcerative colitis showed a much weaker influence regarding the expression of the proteins studied but in case of CYP2C9 and UDP-glucuronosyltransferase, a decrease of expression was observed.
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Affiliation(s)
- Danuta Plewka
- Department of Histology, Medical University of Silesia, Katowice, Poland
| | - Andrzej Plewka
- Department of Proteomics, Medical University of Silesia, Sosnowiec, Poland.
| | - Tomasz Szczepanik
- Department of Proteomics, Medical University of Silesia, Sosnowiec, Poland
| | - Michał Morek
- Department of Proteomics, Medical University of Silesia, Sosnowiec, Poland
| | - Edyta Bogunia
- Department of Proteomics, Medical University of Silesia, Sosnowiec, Poland
| | - Piotr Wittek
- Department of Proteomics, Medical University of Silesia, Sosnowiec, Poland
| | - Czarosław Kijonka
- Department of Proteomics, Medical University of Silesia, Sosnowiec, Poland
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229
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Megaraj V, Zhou X, Xie F, Liu Z, Yang W, Ding X. Role of CYP2A13 in the bioactivation and lung tumorigenicity of the tobacco-specific lung procarcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone: in vivo studies using a CYP2A13-humanized mouse model. Carcinogenesis 2014; 35:131-7. [PMID: 23917075 PMCID: PMC3871935 DOI: 10.1093/carcin/bgt269] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 07/18/2013] [Accepted: 07/30/2013] [Indexed: 11/14/2022] Open
Abstract
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which is abundant in tobacco smoke, is a potent lung procarcinogen. The present study was aimed to prove that transgenic expression of human cytochrome P450 2A13 (CYP2A13), known to be selectively expressed in the respiratory tract and be the most efficient enzyme for NNK bioactivation in vitro, will enhance NNK bioactivation and NNK-induced tumorigenesis in the mouse lung. Kinetic parameters of NNK bioactivation in vitro and incidence of NNK-induced lung tumors in vivo were determined for wild-type, Cyp2a5-null and CYP2A13-humanized (CYP2A13-transgenic/Cyp2a5-null) mice. As expected, in both liver and lung microsomes, the loss of CYP2A5 resulted in significant increases in Michaelis constant (K m) values for the formation of 4-oxo-4-(3-pyridyl)-butanal, representing the reactive intermediate that can lead to the formation of O(6)-methylguanine (O(6)-mG) DNA adducts; however, the gain of CYP2A13 at a fraction of the level of mouse lung CYP2A5 led to recovery of the activity in the lung, but not in the liver. The levels of O(6)-mG, the DNA adduct highly correlated with lung tumorigenesis, were significantly higher in the lungs of CYP2A13-humanized mice than in Cyp2a5-null mice. Moreover, incidences of lung tumorigenesis were significantly greater in CYP2A13-humanized mice than in Cyp2a5-null mice, and the magnitude of the differences in incidence was greater at low (30mg/kg) than at high (200mg/kg) NNK doses. These results indicate that CYP2A13 is a low K m enzyme in catalyzing NNK bioactivation in vivo and support the notion that genetic polymorphisms of CYP2A13 can influence the risks of tobacco-induced lung tumorigenesis in humans.
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Affiliation(s)
- Vandana Megaraj
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
| | - Xin Zhou
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
| | - Fang Xie
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
| | - Zhihua Liu
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
| | - Weizhu Yang
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
| | - Xinxin Ding
- Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
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230
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Kedderis GL, Shepard KG, Recio L. Cytotoxicity of naphthalene toward cells from target and non-target organs in vitro. Chem Biol Interact 2013; 209:85-95. [PMID: 24361489 DOI: 10.1016/j.cbi.2013.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 12/02/2013] [Accepted: 12/09/2013] [Indexed: 11/16/2022]
Abstract
Chronic inhalation exposure to high concentrations of naphthalene produced nasal tumors in rats and lung tumors in female mice. Naphthalene bioactivation is required for target organ toxicity and cytotoxicity in target organs may be involved in tumor development. The present studies characterized the dose-response relationships for naphthalene-induced glutathione (GSH) depletion, effects on cellular ATP, and cytotoxicity in cells from both target (lung, nasal epithelium) and non-target (liver) organs in vitro using cells from F-344 rats, B6C3F1 mice and humans. The cells were incubated with various concentrations of naphthalene in sealed glass flasks for 3h, then placed in monolayer culture in fresh media for 24h to examine the repair or progression of damage. Naphthalene was a low potency cytotoxicant in vitro, with 500 μM frequently observed as a no-observed adverse effect concentration or lowest observed adverse effect concentration. Naphthalene exposure produced dose-dependent decreases in cellular GSH, ATP and viability in rat, mouse and human hepatocytes at concentrations >500 μM. Human nasal respiratory epithelial cells exhibited greater naphthalene cytotoxicity than rat or mouse nasal respiratory epithelial cell preparations. Rat nasal respiratory epithelial cell preparations metabolized naphthalene through pathways leading to the preferential formation of 1,2-naphthoquinone GSH conjugates rather than 1,4-naphthoquinone GSH conjugates observed in rat hepatocytes or mouse nasal respiratory epithelial cells, consistent with the suggestion that this bioactivation pathway may be involved in rat nasal tumor development. Naphthalene exposures of ≥500 μM decreased cellular GSH and ATP in rat, mouse and human lung cell preparations. The variability of the responses of the human lung cell preparations was consistent with the known variability of CYP activities in human lung tissue. The results of these studies can be used as the basis for future studies of the mechanisms involved in naphthalene-induced cytotoxicity and the relevance of the bioactivation pathways for human exposure to naphthalene.
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Affiliation(s)
| | - Kim G Shepard
- Integrated Laboratory Systems Inc., Research Triangle Park, NC 27709, United States
| | - Leslie Recio
- Integrated Laboratory Systems Inc., Research Triangle Park, NC 27709, United States
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231
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Abstract
Acute lung injury (ALI) and its more severe form of clinical manifestation, the acute respiratory distress syndrome is associated with significant dysfunction in air exchange due to inflammation of the lung parenchyma. Several factors contribute to the inflammatory process, including hypoxia (inadequate oxygen), hyperoxia (higher than normal partial pressure of oxygen), inflammatory mediators (such as cytokines), infections (viral and bacterial), and environmental conditions (such as cigarette smoke or noxious gases). However, studies over the past several decades suggest that oxidants formed in the various cells of the lung including endothelial, alveolar, and epithelial cells as well as lung macrophages and neutrophils in response to the factors mentioned above mediate the pathogenesis of ALI. Oxidants modify cellular proteins, lipids, carbohydrates, and DNA to cause their aberrant function. For example, oxidation of lipids changes membrane permeability. Interestingly, recent studies also suggest that spatially and temporally regulated production of oxidants plays an important role antimicrobial defense and immunomodulatory function (such as transcription factor activation). To counteract the oxidants an arsenal of antioxidants exists in the lung to maintain the redox status, but when overwhelmed tissue injury and exacerbation of inflammation occurs. We present below the current understanding of the pathogenesis of oxidant-mediated ALI.
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Affiliation(s)
- J Vidya Sarma
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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232
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Diggs DL, Myers JN, Banks LD, Niaz MS, Hood DB, Roberts LJ, Ramesh A. Influence of dietary fat type on benzo(a)pyrene [B(a)P] biotransformation in a B(a)P-induced mouse model of colon cancer. J Nutr Biochem 2013; 24:2051-63. [PMID: 24231098 PMCID: PMC3904801 DOI: 10.1016/j.jnutbio.2013.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/06/2013] [Accepted: 07/17/2013] [Indexed: 02/06/2023]
Abstract
In the US alone, around 60,000 lives/year are lost due to colon cancer. Diet and environment have been implicated in the development of sporadic colon tumors. The objective of this study was to determine how dietary fat potentiates the development of colon tumors through altered B(a)P biotransformation, using the Adenomatous polyposis coli with Multiple intestinal neoplasia mouse model. Benzo(a)pyrene was administered to mice through tricaprylin, and unsaturated (USF; peanut oil) and saturated (SF; coconut oil) fats at doses of 50 and 100 μg/kg via oral gavage over a 60-day period. Blood, colon, and liver were collected at the end of exposure period. The expression of B(a)P biotransformation enzymes [cytochrome P450 (CYP)1A1, CYP1B1 and glutathione-S-transferase] in liver and colon were assayed at the level of protein, mRNA and activities. Plasma and tissue samples were analyzed by reverse phase high-performance liquid chromatography for B(a)P metabolites. Additionally, DNA isolated from colon and liver tissues was analyzed for B(a)P-induced DNA adducts by the (32)P-postlabeling method using a thin-layer chromatography system. Benzo(a)pyrene exposure through dietary fat altered its metabolic fate in a dose-dependent manner, with 100 μg/kg dose group registering an elevated expression of B(a)P biotransformation enzymes, and greater concentration of B(a)P metabolites, compared to the 50 μg/kg dose group (P<.05). This effect was more pronounced for SF group compared to USF group (P<.05). These findings establish that SF causes sustained induction of B(a)P biotransformation enzymes and extensive metabolism of this toxicant. As a consequence, B(a)P metabolites were generated to a greater extent in colon and liver, whose concentrations also registered a dose-dependent increase. These metabolites were found to bind with DNA and form B(a)P-DNA adducts, which may have contributed to colon tumors in a subchronic exposure regimen.
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Affiliation(s)
- Deacqunita L. Diggs
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Jeremy N. Myers
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Leah D. Banks
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Mohammad S. Niaz
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Darryl B. Hood
- Department of Neuroscience and Pharmacology, Meharry Medical College,Nashville, TN 37208
| | - L. Jackson Roberts
- Departments of Pharmacology and Medicine, Pathology, Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Aramandla Ramesh
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
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233
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Stamou M, Wu X, Kania-Korwel I, Lehmler HJ, Lein PJ. Cytochrome p450 mRNA expression in the rodent brain: species-, sex-, and region-dependent differences. Drug Metab Dispos 2013; 42:239-44. [PMID: 24255117 DOI: 10.1124/dmd.113.054239] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cytochrome P450 (P450) enzymes play a critical role in the activation and detoxication of many neurotoxic chemicals. Although research has largely focused on P450-mediated metabolism in the liver, emerging evidence suggests that brain P450s influence neurotoxicity by modulating local metabolite levels. As a first step toward better understanding the relative role of brain P450s in determining neurotoxic outcome, we characterized mRNA expression of specific P450 isoforms in the rodent brain. Adult mice (male and female) and rats (male) were treated with vehicle, phenobarbital, or dexamethasone. Transcripts for CYP2B, CYP3A, CYP1A2, and the orphan CYP4X1 and CYP2S1 were quantified in the liver, hippocampus, cortex, and cerebellum by quantitative (real-time) polymerase chain reaction. These P450s were all detected in the liver with the exception of CYP4X1, which was detected in rat but not mouse liver. P450 expression profiles in the brain varied regionally. With the exception of the hippocampus, there were no sex differences in regional brain P450 expression profiles in mice; however, there were marked species differences. In the liver, phenobarbital induced CYP2B expression in both species. Dexamethasone induced hepatic CYP2B and CYP3A in mice but not rats. In contrast, brain P450s did not respond to these classic hepatic P450 inducers. Our findings demonstrate that P450 mRNA expression in the brain varies by region, regional brain P450 profiles vary between species, and their induction varies from that of hepatic P450s. These novel data will be useful for designing mechanistic studies to examine the relative role of P450-mediated brain metabolism in neurotoxicity.
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Affiliation(s)
- Marianna Stamou
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California (M.S., P.J.L.) and Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa (X.W., I.K.-K., H.-J.L.)
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234
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Vinothkumar R, Vinoth Kumar R, Sudha M, Viswanathan P, Balasubramanian T, Nalini N. Modulatory effect of troxerutin on biotransforming enzymes and preneoplasic lesions induced by 1,2-dimethylhydrazine in rat colon carcinogenesis. Exp Mol Pathol 2013; 96:15-26. [PMID: 24512697 DOI: 10.1016/j.yexmp.2013.10.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 10/10/2013] [Accepted: 10/21/2013] [Indexed: 01/27/2023]
Abstract
Colon cancer is the third most global oncologic problem faced by medical fraternity. Troxerutin, a flavonoid present in tea, coffee, cereal grains, and a variety of fruits and vegetables, exhibits various pharmacological and biological activities. This study was carried out to investigate the effect of troxerutin on xenobiotic metabolizing enzymes, colonic bacterial enzymes and the development of aberrant crypt foci (ACF) during 1,2-dimethylhydrazine (DMH) induced experimental rat colon carcinogenesis. Male albino Wistar rats were randomly divided into six groups. Group 1 served as control. Group 2 received troxerutin (50 mg/kg b.w., p.o. every day) for 16 weeks. Groups 3-6 received subcutaneous injections of DMH (20 mg/kg b.w.) once a week, for the first four weeks. In addition, groups 4-6 received different doses of troxerutin (12.5, 25, 50 mg/kg b.w., p.o. every day respectively) along with DMH injections. Our results reveal that DMH treated rats exhibited elevated activities of phase I enzymes such as cytochrome P450, cytochrome b5, cytochrome P4502E1, NADPH-cytochrome P450 reductase and NADH-cytochrome b5 reductase and reduced activities of phase II enzymes such as glutathione-S-transferase (GST), DT-diaphorase (DTD) and uridine diphospho glucuronyl transferase (UDPGT) in the liver and colonic mucosa of control and experimental rats. Furthermore, the activities of fecal and colonic mucosal bacterial enzymes, such as β-glucronidase, β-glucosidase, β-galactosidase and mucinase were found to be significantly higher in DMH alone treated rats than those of the control rats. On supplementation with troxerutin to DMH treated rats, the alterations in the activities of the biotransforming enzymes, bacterial enzymes and the pathological changes were significantly reversed, the effect being more pronounced when troxerutin was supplemented at the dose of 25 mg/kg b.w. Thus troxerutin could be considered as a good chemopreventive agent against the formation of preneoplastic lesions in a rat model of colon carcinogenesis.
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Affiliation(s)
- Rajamanickam Vinothkumar
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
| | - Rajenderan Vinoth Kumar
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
| | - Mani Sudha
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
| | - Periyaswamy Viswanathan
- Department of Pathology, Rajah Muthiah Medical College, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
| | - Thangavel Balasubramanian
- Faculty of Marine Sciences, Centre for Advanced Study in Marine Biology, Annamalai University, Parangipettai 608 502, Tamil Nadu, India
| | - Namasivayam Nalini
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India.
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235
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Zhang Z, Lu H, Huan F, Meghan C, Yang X, Wang Y, Wang X, Wang X, Wang SL. Cytochrome P450 2A13 mediates the neoplastic transformation of human bronchial epithelial cells at a low concentration of aflatoxin B1. Int J Cancer 2013; 134:1539-48. [DOI: 10.1002/ijc.28489] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 09/02/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Zhan Zhang
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- State Key Lab of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing People's Republic of China
| | - Huiyuan Lu
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- Animal, Plant and Food Inspection Center; Jiangsu Entry-Exit Inspection and Quarantine Bureau; Nanjing People's Republic of China
| | - Fei Huan
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
| | - Cromie Meghan
- Department of Environmental Toxicology; Texas Tech University; Lubbock TX
| | - Xuejiao Yang
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- State Key Lab of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing People's Republic of China
| | - Yun Wang
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- State Key Lab of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing People's Republic of China
| | - Xichen Wang
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- State Key Lab of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing People's Republic of China
| | - Xinru Wang
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- State Key Lab of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing People's Republic of China
| | - Shou-Lin Wang
- Key Lab of Modern Toxicology of Ministry of Education; School of Public Health; Nanjing Medical University; Nanjing People's Republic of China
- State Key Lab of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing People's Republic of China
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236
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Henderson CJ, McLaughlin LA, Finn RD, Ronseaux S, Kapelyukh Y, Wolf CR. A role for cytochrome b5 in the In vivo disposition of anticancer and cytochrome P450 probe drugs in mice. Drug Metab Dispos 2013; 42:70-7. [PMID: 24115751 DOI: 10.1124/dmd.113.055277] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The role of microsomal cytochrome b5 (Cyb5) in defining the rate of drug metabolism and disposition has been intensely debated for several decades. Recently we described mouse models involving the hepatic or global deletion of Cyb5, demonstrating its central role in in vivo drug disposition. We have now used the cytochrome b5 complete null (BCN) model to determine the role of Cyb5 in the metabolism of ten pharmaceuticals metabolized by a range of cytochrome P450s, including five anticancer drugs, in vivo and in vitro. The extent to which metabolism was significantly affected by the absence of Cyb5 was substrate-dependent; AUC increased (75-245%) and clearance decreased (35-72%) for phenacetin, metoprolol, and chlorzoxazone. Tolbutamide disposition was not significantly altered by Cyb5 deletion, while for midazolam clearance was decreased by 66%. The absence of Cyb5 had no effect on gefitinib and paclitaxel disposition, while significant changes in the in vivo pharmacokinetics were measured for: cyclophosphamide [maximum plasma concentration (Cmax) and terminal half-life increased 55% and 40%, respectively], tamoxifen (AUClast and Cmax increased 370% and 233%, respectively), and anastrozole (AUC and terminal half-life increased 125% and 62%, respectively; clearance down 80%). These data provide strong evidence that both hepatic and extrahepatic Cyb5 levels are an important determinant of in vivo drug disposition catalyzed by a range of cytochrome P450s, including currently prescribed anticancer agents, and that individuality in Cyb5 expression could be a significant determinant in rates of drug disposition in man.
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Affiliation(s)
- Colin J Henderson
- Division of Cancer Research, Medical Research Institute, University of Dundee, and Ninewells Hospital and Medical School, Dundee, United Kingdom
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237
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Systems approaches evaluating the perturbation of xenobiotic metabolism in response to cigarette smoke exposure in nasal and bronchial tissues. BIOMED RESEARCH INTERNATIONAL 2013; 2013:512086. [PMID: 24224167 PMCID: PMC3808713 DOI: 10.1155/2013/512086] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/14/2013] [Accepted: 08/16/2013] [Indexed: 02/03/2023]
Abstract
Capturing the effects of exposure in a specific target organ is a major challenge in risk assessment. Exposure to cigarette smoke (CS) implicates the field of tissue injury in the lung as well as nasal and airway epithelia. Xenobiotic metabolism in particular becomes an attractive tool for chemical risk assessment because of its responsiveness against toxic compounds, including those present in CS. This study describes an efficient integration from transcriptomic data to quantitative measures, which reflect the responses against xenobiotics that are captured in a biological network model. We show here that our novel systems approach can quantify the perturbation in the network model of xenobiotic metabolism. We further show that this approach efficiently compares the perturbation upon CS exposure in bronchial and nasal epithelial cells in vivo samples obtained from smokers. Our observation suggests the xenobiotic responses in the bronchial and nasal epithelial cells of smokers were similar to those observed in their respective organotypic models exposed to CS. Furthermore, the results suggest that nasal tissue is a reliable surrogate to measure xenobiotic responses in bronchial tissue.
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238
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Vinothkumar R, Sudha M, Viswanathan P, Kabalimoorthy J, Balasubramanian T, Nalini N. Modulating effect of d-carvone on 1,2-dimethylhydrazine-induced pre-neoplastic lesions, oxidative stress and biotransforming enzymes, in an experimental model of rat colon carcinogenesis. Cell Prolif 2013; 46:705-20. [PMID: 24118219 DOI: 10.1111/cpr.12062] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/15/2013] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES The present study has aimed to evaluate chemopreventive potential of d-carvone on oxidative stress markers, biotransforming enzymes, incidence of colonic polyps and aberrant crypt foci (ACF) in 1,2-dimethylhydrazine (DMH)-induced experimental colon carcinogenesis. MATERIALS AND METHODS Rats were randomly divided into six groups, with group I serving as control. Group II animals received d-carvone every day orally (20 mg/kg body weight) for 16 weeks; groups III-VI received subcutaneous injections of DMH (20 mg/kg body weight) once a week, for the first 4 weeks. In addition, groups IV-VI received different doses of d-carvone (5, 10 and 20 mg/kg body weight everyday orally) along with DMH injections. RESULTS Our results revealed that supplementation with d-carvone significantly reduced incidence of polyps/ACF and ACF multiplicity in DMH-exposed rats compared to DMH-alone-exposed rats. Moreover, our results showed reduced activities of liver and circulatory antioxidants and increased levels of lipid peroxidation by products in DMH-exposed animals, which were significantly reversed on supplementation with d-carvone. In addition, colonic antioxidants and lipid peroxidation were significantly diminished in DMH-exposed rats, which were significantly elevated on supplementation with d-carvone. Furthermore, we also determined activities of biotransforming enzymes, which were found to be altered in DMH-exposed rats, but reversed on d-carvone supplementation. All these observations of changes were supported by histochemical findings. CONCLUSION Overall, results obtained from this study suggest that d-carvone at 10 mg/kg body weight provided optimum protection and could be used as an effective chemopreventive agent against colon carcinogenesis induced by DMH.
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Affiliation(s)
- R Vinothkumar
- Faculty of Science, Department of Biochemistry and Biotechnology, Annamalai University, Chidambaram, Tamil Nadu, 608 002, India
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239
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Richtwerte für Naphthalin und Naphthalin-ähnliche Verbindungen in der Innenraumluft. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2013. [DOI: 10.1007/s00103-013-1836-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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240
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Blake LC, Roy A, Neul D, Schoenen FJ, Aubé J, Scott EE. Benzylmorpholine analogs as selective inhibitors of lung cytochrome P450 2A13 for the chemoprevention of lung cancer in tobacco users. Pharm Res 2013; 30:2290-302. [PMID: 23756756 PMCID: PMC3781598 DOI: 10.1007/s11095-013-1054-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/02/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), one of the most prevalent and procarcinogenic compounds in tobacco, is bioactivated by respiratory cytochrome P450 (CYP) 2A13, forming DNA adducts and initiating lung cancer. CYP2A13 inhibition offers a novel strategy for chemoprevention of tobacco-associated lung cancer. METHODS Twenty-four analogs of a 4-benzylmorpholine scaffold identified by high throughput screening were evaluated for binding and inhibition of both functional human CYP2A enzymes, CYP2A13 and the 94%-identical hepatic CYP2A6, whose inhibition is undesirable. Thus, selectivity is a major challenge in compound design. RESULTS A key feature resulting in CYP2A13-selective binding and inhibition was substitution at the benzyl ortho position, with three analogs being >25-fold selective for CYP2A13 over CYP2A6. CONCLUSIONS Two such analogs were negative for genetic and hERG toxicities and metabolically stable in human lung microsomes, but displayed rapid metabolism in human liver and in mouse and rat lung and liver microsomes, likely due to CYP2B-mediated degradation. A specialized knockout mouse mimicking the human lung demonstrates compound persistence in lung and provides an appropriate test model. Compound delivered by inhalation may be effective in the lung but rapidly cleared otherwise, limiting systemic exposure.
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Affiliation(s)
- Linda C. Blake
- Department of Medicinal Chemistry, 1251 Wescoe Hall Dr., University of Kansas, Lawrence, KS 66045, United States
| | - Anuradha Roy
- High Throughput Screening Laboratory, 2034 Becker Drive, University of Kansas, Lawrence, KS 66047, United States
| | - David Neul
- Pharmacokinetics, Dynamics and Metabolism, Pfizer Inc., La Jolla, CA 92121
| | - Frank J. Schoenen
- University of Kansas Specialized Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, KS 66047
| | - Jeffrey Aubé
- Department of Medicinal Chemistry, 1251 Wescoe Hall Dr., University of Kansas, Lawrence, KS 66045, United States
- University of Kansas Specialized Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, KS 66047
| | - Emily E. Scott
- Department of Medicinal Chemistry, 1251 Wescoe Hall Dr., University of Kansas, Lawrence, KS 66045, United States
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241
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Potent inhibition of cytochrome P450 2B6 by sibutramine in human liver microsomes. Chem Biol Interact 2013; 205:11-9. [DOI: 10.1016/j.cbi.2013.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/30/2013] [Accepted: 06/03/2013] [Indexed: 11/20/2022]
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242
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Betton GR. A review of the toxicology and pathology of the gastrointestinal tract. Cell Biol Toxicol 2013; 29:321-38. [DOI: 10.1007/s10565-013-9257-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/14/2013] [Indexed: 02/08/2023]
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243
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Zhang Z, Yang X, Wang Y, Wang X, Lu H, Zhang X, Xiao X, Li S, Wang X, Wang SL. Cytochrome P450 2A13 is an efficient enzyme in metabolic activation of aflatoxin G1 in human bronchial epithelial cells. Arch Toxicol 2013; 87:1697-707. [PMID: 23907605 DOI: 10.1007/s00204-013-1108-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/23/2013] [Indexed: 10/26/2022]
Abstract
Cytochrome P450 2A13 (CYP2A13) is an extrahepatic enzyme that mainly expresses in human respiratory system, and it is reported to mediate the metabolic activation of aflatoxin B1. Due to the structural similarity, AFG1 is predicted to be metabolized by CYP2A13. However, the role of CYP2A13 in metabolic activation of AFG1 is unclear. In present study, human bronchial epithelial cells that stably express CYP2A13 (B-2A13) were used to conduct the effects of AFG1 on cytotoxicity, apoptosis, DNA damages, and their response protein expression. Low concentrations of AFG1 induced significant cytotoxicity and apoptosis, which was consistent with the increased expressions of pro-apoptotic proteins, such as C-PARP and C-caspase-3. In addition, AFG1 increased 8-OHdG and γH2AX in the nuclies and induced S phase arrest and DNA damage in B-2A13 cells, and the proteins related to DNA damage responses, such as ATM, ATR, Chk2, p53, BRCA1, and γH2AX, were activated. All the above effects were inhibited by nicotine (a substrate of CYP2A13) or 8-MOP (an inhibitor of CYP enzymes), confirming that CYP2A13 mediated the AFG1-induced cytotoxicity and DNA damages. Collectively, our findings first demonstrate that CYP2A13 might be an efficient enzyme in metabolic activation of AFG1 and helps provide a new insight into adverse effects of AFG1 in human respiratory system.
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Affiliation(s)
- Zhan Zhang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 818 East Tianyuan Rd., Nanjing, 211166, China
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244
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CYP1B1 L432V Polymorphism and Lung Cancer Risk in the Iranian Population. IRANIAN JOURNAL OF BIOTECHNOLOGY 2013. [DOI: 10.5812/ijb.12197] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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245
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El Sadeck N, Ibrahim BM, Alassal MA. Cytochrome P450-isoenzyme 1A1 in susceptibility to tobacco-related lung cancer. Asian Cardiovasc Thorac Ann 2013; 22:315-8. [PMID: 24585908 DOI: 10.1177/0218492313492987] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Tobacco smoke contains many carcinogens that may mediate susceptibility to lung cancer. Cytochrome P450 isoenzyme 1A1 activity and expression increases several fold in lung cancer due to smoking. Finding the role of cytochrome P450 1A1 in susceptibility to tobacco-related lung cancer may be important to predict the outcome in early stage cancer, and may result in an improved survival rate. PATIENTS AND METHODS This study was carried on 2 groups of patients: group A was 20 patients with operable smoking-related lung cancer, who underwent surgery at the time of diagnosis; group B was 20 nonsmokers without lung cancer who underwent chest exploration following road traffic accidents. Specimens were obtained from tumor tissue and surrounding healthy tissue in group A patients, and from healthy lung tissue in group B patients. These specimens were sent for measurement of protein content and cytochrome P450 1A1 activity. RESULTS There was significantly greater tissue cytochrome P450 1A1 activity in group A compared to group B. Patients with stage II cancer showed significantly higher levels of tissue cytochrome P450 1A1 activity than those with stage I. There was also a significant difference in tissue cytochrome P450 1A1 activity between the tumor tissue and the tissue surrounding the tumor. CONCLUSION Carcinogens in smoke increase cytochrome P450 1A1 activity, which might be considered to play a role in cigarette smoking-induced lung cancer.
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Affiliation(s)
- Nabil El Sadeck
- Cardiothoracic Surgery Department, Zagazig University, Egypt
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Linares OA, Daly D, Stefanovski D, Boston RC. A new model for using quantitative urine testing as a diagnostic tool for oxycodone treatment and compliance. J Pain Palliat Care Pharmacother 2013; 27:244-54. [PMID: 23879213 DOI: 10.3109/15360288.2013.800180] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We conducted a prospective, randomized, cross-sectional study to develop and validate a new model to predict oxycodone in urine that can be used to help evaluate whether patients are complying with their oxycodone dosing regimens. We studied 20 patients: eight black women, two white women, six black men, and four white men; ages 48 ± 10 years (mean ± SD); weight 97 ± 32 kg. Pain levels before treatment averaged 9.5 ± 0.9 out of 10. We prescribed oral oxycodone for each patient, tailoring the dosing regimen using clinical pharmacokinetics and measured the oxycodone concentration in each patient's urine 10 to 14 days after starting the dosing regimen. For each patient, we predicted oxycodone in their urine using our model, checked the actual concentration, and compared predicted with actual concentrations. For 18 of 20 patients (90%), actual results fell within ±10% of our model's prediction. One patient was 35% below the prediction; the other was 51% above. Our model accurately predicts oxycodone in urine (±10% for 90% of the patients). The model appears clinically useful for evaluating the results of a quantitative urine test, since it objectively discriminates between (1) a "normal" patient complying with their oxycodone dosing regimen, and (2) a patient who may require genetic testing to distinguish between unusual metabolism or abuse.
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Affiliation(s)
- Oscar A Linares
- Plymouth Pharmacokinetic Modeling Study Group, Plymouth, Michigan 48170, USA.
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Naveenkumar C, Raghunandakumar S, Asokkumar S, Binuclara J, Rajan B, Premkumar T, Devaki T. Mitigating role of baicalein on lysosomal enzymes and xenobiotic metabolizing enzyme status during lung carcinogenesis of Swiss albino mice induced by benzo(a)pyrene. Fundam Clin Pharmacol 2013; 28:310-22. [PMID: 23834621 DOI: 10.1111/fcp.12036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 03/18/2013] [Accepted: 04/30/2013] [Indexed: 12/31/2022]
Abstract
The lungs mainly serve as a primary site for xenobiotic metabolism and constitute an important defense mechanism against inhalation of carcinogens. Our current study aimed to evaluate the chemotherapeutic efficacy of baicalein (BE) in Swiss albino mice exposed to tobacco-specific carcinogen benzo(a)pyrene [B(a)P] for its ability to mitigate pulmonary carcinogenesis. Here, we report that altered activities/levels of lysosomal enzymes (cathepsin-D, cathepsin-B, acid phosphatase, β-D-galactosidase, β-D-glucuronidase, and β-D-N-acetyl glucosaminidase), phase I biotransformation enzymes (cytochrome P450, cytochrome b5, NADPH-cytochrome P450 reductase, and NADH-cytochrome b5 reductase), and phase II enzymes (glutathione S-transferase, UDP-glucuronyl transferase, and DT-diaphorase) were observed in the B(a)P-induced mice. Treatment with BE significantly restored back the activities/levels of lysosomal enzymes, phase I and phase II biotransformation enzymes. Moreover, assessment of lysosomal abnormalities by transmission electron microscopic examination revealed that BE treatment effectively counteract B(a)P-induced oxidative damages. Protein expression levels studied by immunohistochemistry, immunofluorescence, and immunoblot analysis of CYP1A1 revealed that BE treatment effectively negate B(a)P-induced upregulated expression of CYP1A1. Further analysis of scanning electron microscopic studies in lung was carried out to substantiate the anticarcinogenic effect of BE. The overall data suggest that BE treatment significantly inhibits lysosomal and microsomal dysfunction, thus revealing its potent anticarcinogenic effect.
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Yang X, Zhang Z, Wang X, Wang Y, Zhang X, Lu H, Wang SL. Cytochrome P450 2A13 enhances the sensitivity of human bronchial epithelial cells to aflatoxin B1-induced DNA damage. Toxicol Appl Pharmacol 2013; 270:114-21. [DOI: 10.1016/j.taap.2013.04.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/08/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
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Seizure protection by intrapulmonary delivery of midazolam in mice. Neuropharmacology 2013; 73:425-31. [PMID: 23774136 DOI: 10.1016/j.neuropharm.2013.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 05/12/2013] [Accepted: 06/04/2013] [Indexed: 11/21/2022]
Abstract
The lung provides a portal of entry that could be used to rapidly deliver anticonvulsant substances to the brain to treat seizures. In the present study, we demonstrate that midazolam, a water-soluble anticonvulsant benzodiazepine, confers potent seizure protection when administered via the intrapulmonary route. High dose (100 mg/kg) intraperitoneal midazolam induced loss-of-righting reflex in mice. Lower doses of midazolam (100-1000 μg/kg) when administered intraperitoneally did not induce loss-of-righting reflex but protected animals against pentylenetetrazol (PTZ)-induced seizures. Intrapulmonary administration of midazolam via a tracheal cannula protected against intraperitoneal PTZ seizures at lower doses. The minimal intraperitoneal and intravenous doses of midazolam required to elevate the threshold for seizure signs induced by intravenous PTZ were 500 and 100 μg/kg, respectively, whereas the minimal intrapulmonary midazolam dose was 12.5 μg/kg. Intratracheal midazolam caused a large increase in intravenous PTZ threshold 5 min after administration but the effect declined rapidly over 60 min and no antiseizure activity was evident at 120 min. The minimal intraperitoneal doses of midazolam required to elevate the threshold for seizure signs induced by intravenous picrotoxin and kainic acid were 100 and 2000 μg/kg, respectively; the corresponding values for intratracheal midazolam were 25 and 100 μg/kg, respectively. We conclude that midazolam is a highly effective anticonvulsant when administered by the intrapulmonary route. Midazolam is substantially more potent when delivered into the lung than when administered intraperitoneally or intravenously. Inhalation could be an alternative to other routes of administration for the delivery of midazolam to rapidly abort acute seizures.
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Wang K, Guengerich FP. Reduction of aromatic and heterocyclic aromatic N-hydroxylamines by human cytochrome P450 2S1. Chem Res Toxicol 2013; 26:993-1004. [PMID: 23682735 DOI: 10.1021/tx400139p] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals, and there is also strong evidence of some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anticancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions [Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740-1751]. In the study presented here, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs.
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Affiliation(s)
- Kai Wang
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University, School of Medicine, 638 Robinson Research Building, 2200 Pierce Avenue, Nashville, Tennessee 37232-0146, USA
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