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Iammarino M, Marino R, Nardelli V, Ingegno M, Albenzio M. Red Meat Heating Processes, Toxic Compounds Production and Nutritional Parameters Changes: What about Risk-Benefit? Foods 2024; 13:445. [PMID: 38338580 PMCID: PMC10855356 DOI: 10.3390/foods13030445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
The heating process is a crucial step that can lead to the formation of several harmful chemical compounds in red meat such as heterocyclic aromatic amines, N-Nitrosamines, polycyclic aromatic hydrocarbons and acrylamide. Meat has high nutritional value, providing essential amino acids, bioactive compounds and several important micronutrients which can also be affected by heating processes. This review aims to provide an updated overview of the effects of different heating processes on both the safety and nutritional parameters of cooked red meat. The most-used heating processes practices were taken into consideration in order to develop a risk-benefit scenario for each type of heating process and red meat.
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Affiliation(s)
- Marco Iammarino
- Department of Chemistry, Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, 71121 Foggia, Italy; (V.N.); (M.I.)
| | - Rosaria Marino
- Department of Agriculture, Food, Natural Resources and Engineering (DAFNE), University of Foggia, 71121 Foggia, Italy;
| | - Valeria Nardelli
- Department of Chemistry, Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, 71121 Foggia, Italy; (V.N.); (M.I.)
| | - Mariateresa Ingegno
- Department of Chemistry, Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, 71121 Foggia, Italy; (V.N.); (M.I.)
| | - Marzia Albenzio
- Department of Agriculture, Food, Natural Resources and Engineering (DAFNE), University of Foggia, 71121 Foggia, Italy;
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McCarty KD, Sullivan ME, Tateishi Y, Hargrove TY, Lepesheva GI, Guengerich FP. Processive kinetics in the three-step lanosterol 14α-demethylation reaction catalyzed by human cytochrome P450 51A1. J Biol Chem 2023; 299:104841. [PMID: 37209823 PMCID: PMC10285260 DOI: 10.1016/j.jbc.2023.104841] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023] Open
Abstract
Cytochrome P450 (P450, CYP) family 51 enzymes catalyze the 14α-demethylation of sterols, leading to critical products used for membranes and the production of steroids, as well as signaling molecules. In mammals, P450 51 catalyzes the 3-step, 6-electron oxidation of lanosterol to form (4β,5α)-4,4-dimethyl-cholestra-8,14,24-trien-3-ol (FF-MAS). P450 51A1 can also use 24,25-dihydrolanosterol (a natural substrate in the Kandutsch-Russell cholesterol pathway). 24,25-Dihydrolanosterol and the corresponding P450 51A1 reaction intermediates, the 14α-alcohol and -aldehyde derivatives of dihydrolanosterol, were synthesized to study the kinetic processivity of the overall 14α-demethylation reaction of human P450 51A1. A combination of steady-state kinetic parameters, steady-state binding constants, dissociation rates of P450-sterol complexes, and kinetic modeling of the time course of oxidation of a P450-dihydrolanosterol complex showed that the overall reaction is highly processive, with koff rates of P450 51A1-dihydrolanosterol and the 14α-alcohol and 14α-aldehyde complexes being 1 to 2 orders of magnitude less than the forward rates of competing oxidations. epi-Dihydrolanosterol (the 3α-hydroxy analog) was as efficient as the common 3β-hydroxy isomer in the binding and formation of dihydro FF-MAS. The common lanosterol contaminant dihydroagnosterol was found to be a substrate of human P450 51A1, with roughly one-half the activity of dihydrolanosterol. Steady-state experiments with 14α-methyl deuterated dihydrolanosterol showed no kinetic isotope effect, indicating that C-14α C-H bond breaking is not rate-limiting in any of the individual steps. The high processivity of this reaction generates higher efficiency and also renders the reaction less sensitive to inhibitors.
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Affiliation(s)
- Kevin D McCarty
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Molly E Sullivan
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Yasuhiro Tateishi
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Tatiana Y Hargrove
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Galina I Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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3
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Snodin DJ. Mutagenic impurities in pharmaceuticals: A critical assessment of the cohort of concern with a focus on N-nitrosamines. Regul Toxicol Pharmacol 2023; 141:105403. [PMID: 37116739 DOI: 10.1016/j.yrtph.2023.105403] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 04/30/2023]
Abstract
The TTC (Threshold of Toxicological Concern; set at 1.5 μg/day for pharmaceuticals) defines an acceptable patient intake for any unstudied chemical posing a negligible risk of carcinogenicity or other toxic effects. A group of high potency mutagenic carcinogens, defined solely by the presence of particular structural alerts, are referred to as the "cohort of concern" (CoC); aflatoxin-like-, N-nitroso-, and alkyl-azoxy compounds are considered to pose a significant carcinogenic risk at intakes below the TTC. Kroes et al.2004, derived values for the TTC and CoC in the context of food components, employing a non-transparent dataset never placed in the public domain. Using a reconstructed all-carcinogen dataset from relevant publications, it is now clear that there are exceptions for all three CoC structural classes. N-Nitrosamines represent 62% of the N-nitroso class in the reconstructed dataset. Employing a contemporary dataset, 20% are negative in rodent carcinogenicity bioassays with less than 50% of N-nitrosamines estimated to fall into the highest risk category. It is recommended that CoC nitrosamines are identified by compound-specific data rather than structural alerts. Thus, it should be possible to distinguish CoC from non-CoC N-nitrosamines in the context of mutagenic impurities described in ICH M7 (R1).
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Affiliation(s)
- David J Snodin
- Xiphora Biopharma Consulting, 9 Richmond Apartments, Redland Court Road, Bristol, BS6 7BG, UK.
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4
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You G, Zeng L, Tanaka H, Ohta E, Fujii T, Ohshima K, Tanaka M, Hamajima N, Viwatthanasittiphong C, Muangphot M, Chenvidhya D, Jedpiyawongse A, Sripa B, Miwa M, Honjo S. Polymorphism of genes encoding drug-metabolizing and inflammation-related enzymes for susceptibility to cholangiocarcinoma in Thailand. World J Gastrointest Pathophysiol 2023; 14:21-33. [PMID: 37035273 PMCID: PMC10074948 DOI: 10.4291/wjgp.v14.i2.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 02/19/2023] [Accepted: 03/15/2023] [Indexed: 03/21/2023] Open
Abstract
BACKGROUND Cholangiocarcinoma (CCA) is an intractable cancer, and its incidence in northeastern Thailand is the highest worldwide. Infection with the liver fluke Opisthorchis viverrini (OV) has been associated with CCA risk. However, animal experiments have suggested that OV alone does not induce CCA, but its combination with a chemical carcinogen like nitrosamine can cause experimentally induced CCA in hamsters. Therefore, in humans, other environmental and genetic factors may also be involved.
AIM To examine relations between risk for CCA and genetic polymorphisms in carcinogen-metabolizing and inflammation-related genes.
METHODS This hospital-based case-control study enrolled 95 case-control pairs matched by age (± 5 years) and sex. We examined relations between risk for CCA and genetic polymorphisms in carcinogen-metabolizing and inflammation-related genes, serum anti-OV, alcohol consumption, and smoking. Polymorphisms of CYP2E1, IL-6 (-174 and -634), IL-10 (-819), and NF-κB (-94) and their co-occurrence with polymorphisms in the drug-metabolizing enzyme gene GSTT1 or GSTM1 were also analyzed.
RESULTS Although CCA risk was not significantly associated with any single polymorphism, persons with the GSTT1 wild-type and CYP2E1 c1/c2 + c2/c2 genotype had an increased risk (OR = 3.33, 95%CI: 1.23-9.00) as compared with persons having the GSTT1 wild-type and CYP2E1 c1/c1 wild genotype. The presence of anti-OV in serum was associated with a 7- to 11-fold increased risk, and smoking level was related to an OR of 1.5-1.8 in multivariable analyses adjusted for each of the seven genetic polymorphisms.
CONCLUSION In addition to infection with OV, gene-gene interactions may be considered as one of the risk factors for CCA development.
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Affiliation(s)
- Gyokukou You
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Lu Zeng
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Hideaki Tanaka
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Emi Ohta
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Takahiro Fujii
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Kazuhiko Ohshima
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Masakazu Tanaka
- Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima 890-8544, Kagoshima, Japan
| | - Nobuyuki Hamajima
- Department of Healthcare Administration, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Aichi, Japan
| | | | - Mantana Muangphot
- Department of Pathology, Ubon Cancer Centre, Ubon Ratchathani 34000, Thailand
| | | | | | - Banchob Sripa
- Department of Pathology, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Masanao Miwa
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Shiga, Japan
| | - Satoshi Honjo
- Department of Paediatirics, National Hospital Organization, Fukuoka National Hospital, Fukuoka 811-1394, Fukuoka, Japan
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Hogstrand C, (Ron) Hoogenboom L, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Vleminckx C, Wallace H, Romualdo B, Cristina F, Stephen H, Marco I, Mosbach‐Schulz O, Riolo F, Christodoulidou A, Grasl‐Kraupp B. Risk assessment of N-nitrosamines in food. EFSA J 2023; 21:e07884. [PMID: 36999063 PMCID: PMC10043641 DOI: 10.2903/j.efsa.2023.7884] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023] Open
Abstract
EFSA was asked for a scientific opinion on the risks to public health related to the presence of N-nitrosamines (N-NAs) in food. The risk assessment was confined to those 10 carcinogenic N-NAs occurring in food (TCNAs), i.e. NDMA, NMEA, NDEA, NDPA, NDBA, NMA, NSAR, NMOR, NPIP and NPYR. N-NAs are genotoxic and induce liver tumours in rodents. The in vivo data available to derive potency factors are limited, and therefore, equal potency of TCNAs was assumed. The lower confidence limit of the benchmark dose at 10% (BMDL10) was 10 μg/kg body weight (bw) per day, derived from the incidence of rat liver tumours (benign and malignant) induced by NDEA and used in a margin of exposure (MOE) approach. Analytical results on the occurrence of N-NAs were extracted from the EFSA occurrence database (n = 2,817) and the literature (n = 4,003). Occurrence data were available for five food categories across TCNAs. Dietary exposure was assessed for two scenarios, excluding (scenario 1) and including (scenario 2) cooked unprocessed meat and fish. TCNAs exposure ranged from 0 to 208.9 ng/kg bw per day across surveys, age groups and scenarios. 'Meat and meat products' is the main food category contributing to TCNA exposure. MOEs ranged from 3,337 to 48 at the P95 exposure excluding some infant surveys with P95 exposure equal to zero. Two major uncertainties were (i) the high number of left censored data and (ii) the lack of data on important food categories. The CONTAM Panel concluded that the MOE for TCNAs at the P95 exposure is highly likely (98-100% certain) to be less than 10,000 for all age groups, which raises a health concern.
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Wenzel J, Schmidt F, Blumrich M, Amberg A, Czich A. Predicting DNA-Reactivity of N-Nitrosamines: A Quantum Chemical Approach. Chem Res Toxicol 2022; 35:2068-2084. [PMID: 36302168 DOI: 10.1021/acs.chemrestox.2c00217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
N-Nitrosamines (NAs) are a class of reactive organic chemicals that humans may be exposed to from environmental sources, food but also impurities in pharmaceutical preparations. Some NAs were identified as DNA-reactive mutagens and many of those have been classified as probable human carcinogens. Beyond high-potency mutagenic carcinogens that need to be strictly controlled, NAs of low potency need to be considered for risk assessment as well. NA impurities and nitrosylated products of active pharmaceutical ingredients (APIs) often arise from production processes or degradation. Most NAs require metabolic activation to ultimately become carcinogens, and their activation can be appropriately described by first-principles computational chemistry approaches. To this end, we treat NA-induced DNA alkylation as a series of subsequent association and dissociation reaction steps that can be calculated stringently by density functional theory (DFT), including α-hydroxylation, proton transfer, hydroxyl elimination, direct SN2/SNAr DNA alkylation, competing hydrolysis and SN1 reactions. Both toxification and detoxification reactions are considered. The activation reactions are modeled by DFT at a high level of theory with an appropriate solvent model to compute Gibbs free energies of the reactions (thermodynamical effects) and activation barriers (kinetic effects). We study congeneric series of aliphatic and cyclic NAs to identify trends. Overall, this work reveals detailed insight into mechanisms of activation for NAs, suggesting that individual steric and electronic factors have directing and rate-determining influence on the formation of carbenium ions as the ultimate pro-mutagens and thus carcinogens. Therefore, an individual risk assessment of NAs is suggested, as exemplified for the complex API-like 4-(N-nitroso-N-methyl)aminoantipyrine which is considered as low-potency NA by in silico prediction.
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Affiliation(s)
- Jan Wenzel
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Friedemann Schmidt
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Matthias Blumrich
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Alexander Amberg
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Andreas Czich
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
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Li Y, Hecht SS. Metabolic Activation and DNA Interactions of Carcinogenic N-Nitrosamines to Which Humans Are Commonly Exposed. Int J Mol Sci 2022; 23:ijms23094559. [PMID: 35562949 PMCID: PMC9105260 DOI: 10.3390/ijms23094559] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 02/04/2023] Open
Abstract
Carcinogenic N-nitrosamine contamination in certain drugs has recently caused great concern and the attention of regulatory agencies. These carcinogens-widely detectable in relatively low levels in food, water, cosmetics, and drugs-are well-established and powerful animal carcinogens. The electrophiles resulting from the cytochrome P450-mediated metabolism of N-nitrosamines can readily react with DNA and form covalent addition products (DNA adducts) that play a central role in carcinogenesis if not repaired. In this review, we aim to provide a comprehensive and updated review of progress on the metabolic activation and DNA interactions of 10 carcinogenic N-nitrosamines to which humans are commonly exposed. Certain DNA adducts such as O6-methylguanine with established miscoding properties play central roles in the cancer induction process, whereas others have been linked to the high incidence of certain types of cancers. We hope the data summarized here will help researchers gain a better understanding of the bioactivation and DNA interactions of these 10 carcinogenic N-nitrosamines and facilitate further research on their toxicologic and carcinogenic properties.
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Affiliation(s)
- Yupeng Li
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: ; Tel.: +1-612-624-8187
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
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Abu-Bakar A, Tan BH, Halim H, Ramli S, Pan Y, Ong6 CE. Cytochromes P450: Role in Carcinogenesis and Relevance to Cancers. Curr Drug Metab 2022; 23:355-373. [DOI: 10.2174/1389200223666220328143828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/06/2021] [Accepted: 01/25/2022] [Indexed: 11/22/2022]
Abstract
Abstracts:
Cancer is a leading factor of mortality globally. Cytochrome P450 (CYP) enzymes play a pivotal role in the biotransformation of both endogenous and exogenous compounds. Evidence from numerous epidemiological, animal, and clinical studies points to instrumental role of CYPs in cancer initiation, metastasis, and prevention. Substantial research has found that CYPs are involved in activating different carcinogenic chemicals in the environment, such as polycyclic aromatic hydrocarbons and tobacco-related nitrosamines. Electrophilic intermediates produced from these chemicals can covalently bind to DNA, inducing mutation and cellular transformation that collectively result in cancer development. While bioactivation of procarcinogens and promutagens by CYPs has long been established, the role of CYP-derived endobiotics in carcinogenesis has emerged in recent years. Eicosanoids derived from arachidonic acid via CYP oxidative pathways have been implicated in tumorigenesis, cancer progression and metastasis. The purpose of this review is to update on the current state of knowledge about the cancer molecular mechanism involving CYPs with focus on the biochemical and biotransformation mechanisms in the various CYP-mediated carcinogenesis, and the role of CYP-derived reactive metabolites, from both external and endogenous sources, on cancer growth and tumour formation.
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Affiliation(s)
- A’edah Abu-Bakar
- Product Stewardship and Toxicology, Group Health, Safety, Security and Environment, PETRONAS, Kuala Lumpur, Malaysia
| | - Boon Hooi Tan
- Division of Applied Biomedical Sciences and Biotechnology, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Hasseri Halim
- Faculty of Pharmacy, Universiti Teknologi MARA, Selangor, 42300 Puncak Alam, Selangor, Malaysia
| | - Salfarina Ramli
- Faculty of Pharmacy, Universiti Teknologi MARA, Selangor, 42300 Puncak Alam, Selangor, Malaysia
| | - Yan Pan
- Department of Biomedical Science, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia
| | - Chin Eng Ong6
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
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Abstract
The detection of N-nitrosodimethylamine (NDMA) in several marketed drugs led regulatory agencies to require that N-nitrosamine risk assessments be performed on all marketed medical products [EMA/351053/2019 rev 1 (2019)]. Regulation of N-nitrosamine impurity levels in pharmaceutical drug substances and products is described in the ICH M7(R1) guideline where they are referred to as "cohort-of-concern" compounds as several are potent rodent carcinogens [Kroes et. al. 2004]. EMA, U.S. FDA and other regulatory agencies have set provisional acceptable daily intake limits for N-nitrosamines calculated from rodent carcinogenicity TD50 values for experimentally measured N-nitrosamines or the measured TD50 values of close analogs. The class-specific limit can be adjusted based upon a structure activity relationship analysis (SAR) and comparison with analogs having established carcinogenicity data [EMA/369136/2020, (2020)]. To investigate whether improvements in SARs can more accurately predict N-nitrosamine carcinogenic potency, an ad hoc workgroup of 23 companies and universities was established with the goals of addressing several scientific and regulatory issues including: reporting and review of N-nitrosamine mutagenicity and carcinogenicity reaction mechanisms, collection and review of available, public relevant experimental data, development of structure-activity relationships consistent with mechanisms for prediction of N-nitrosamine carcinogenic potency categories, and improved methods for calculating acceptable intake limits for N-nitrosamines based upon mechanistic analogs. Here we describe this collaboration and review our progress to date towards development of mechanistically based structure-activity relationships. We propose improving risk assessment of N-nitrosamines by first establishing the dominant reaction mechanism prior to retrieving an appropriate set of close analogs for use in read-across exercises.
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Wang JH, Hwang SJ, Son CG. Comparative Analysis of the Antioxidative and Hepatoprotective Activities of Dimethyl Diphenyl Bicarboxylate in Four Animal Models of Hepatic Injury. Antioxidants (Basel) 2021; 10:1508. [PMID: 34679643 DOI: 10.3390/antiox10101508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/13/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
As a well-known hepatoprotective and antioxidant agent, dimethyl diphenyl bicarboxylate (DDB) has frequently been employed to remedy various liver diseases. However, it is still uncertain whether DDB exerts consistent hepatoprotective and antioxidative activities against varying degrees of hepatic damage. Therefore, DDB (100, 25, 5, or 50 mg/kg depending on the model) was administered to animals in four representative models of liver injury (CCl4 chemical acute model, DMN subchronic model, TAA chronic model, and restraint stress psychological acute model). Horizontal comparative analysis indicated that DDB significantly lowered the excess serum AST and ALT levels in the CCl4 and DMN models but not in the TAA and restraint stress models. In accordance with this result, DDB markedly reduced oxidative stress indices (hepatic MDA and ROS) but restored five main antioxidant components (GSH content, GSH-peroxidase, GSH-reductase, SOD, and catalase activity) in the CCl4 and DMN models. DDB failed to normalize oxidative stressors in the restraint stress-induced injury model and restore these five antioxidant components in the TAA model. Overall, our results produced a comprehensive overview of the effects of DDB on oxidative stressors and the main antioxidative components using four animal models. These findings will provide valuable clues to guide therapeutic clinical applications.
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Elder DP, Johnson GE, Snodin DJ. Tolerability of risk: A commentary on the nitrosamine contamination issue. J Pharm Sci 2021; 110:2311-2328. [PMID: 33705731 DOI: 10.1016/j.xphs.2021.02.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/23/2021] [Accepted: 02/23/2021] [Indexed: 11/16/2022]
Abstract
For decades, regulators have grappled with different approaches to address the issue of control of impurities. Safety-based limits, such as permissible daily exposure (PDE), acceptable intake (AI), threshold of toxicological concern (TTC) and less than lifetime limits (LTL) have all been used. For many years these safety-based limits have been recognized as virtually safe doses (VSDs). Recently, however, many regulatory agencies are seeking to impose limits for N-nitrosamine impurities, which are significantly below the VSD. This commentary will discuss the evolution of safety-based limits for impurities, provide an overview of the valsartan N-nitrosamine contamination issue and review the toxicology of N-nitrosamines. The outcome of a lessons-learned exercise on sartan medications undertaken by the European Medicines Agency (EMA) will also be discussed. The review will also highlight the many analytical challenges inherent with controlling impurities to ppb-based limits. The use of highly sensitive, low ppb limits, methods may lead to future issues of batch rejection, based on false positives. Regulators initially viewed the N-nitrosamine risk as being insufficient to prompt immediate product discontinuation and patients were specifically advised to continue using their affected medication. Patients were also informed that exposure to N-nitrosamines is extremely common via food and drinking water.
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Kuang Y, Cao H, Tang H, Chew J, Chen W, Shi X, Wu J. Visible light driven deuteration of formyl C-H and hydridic C(sp 3)-H bonds in feedstock chemicals and pharmaceutical molecules. Chem Sci 2020; 11:8912-8918. [PMID: 34123145 PMCID: PMC8163369 DOI: 10.1039/d0sc02661a] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/29/2020] [Indexed: 12/16/2022] Open
Abstract
Deuterium labelled compounds are of significant importance in chemical mechanism investigations, mass spectrometric studies, diagnoses of drug metabolisms, and pharmaceutical discovery. Herein, we report an efficient hydrogen deuterium exchange reaction using deuterium oxide (D2O) as the deuterium source, enabled by merging a tetra-n-butylammonium decatungstate (TBADT) hydrogen atom transfer photocatalyst and a thiol catalyst under light irradiation at 390 nm. This deuteration protocol is effective with formyl C-H bonds and a wide range of hydridic C(sp3)-H bonds (e.g. α-oxy, α-thioxy, α-amino, benzylic, and unactivated tertiary C(sp3)-H bonds). It has been successfully applied to the high incorporation of deuterium in 38 feedstock chemicals, 15 pharmaceutical compounds, and 6 drug precursors. Sequential deuteration between formyl C-H bonds of aldehydes and other activated hydridic C(sp3)-H bonds can be achieved in a selective manner.
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Affiliation(s)
- Yulong Kuang
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
| | - Hui Cao
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
| | - Haidi Tang
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
| | - Junhong Chew
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
| | - Wei Chen
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
| | - Xiangcheng Shi
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
| | - Jie Wu
- Department of Chemistry, National University of Singapore 3 Science Drive 3 117543 Republic of Singapore
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George J, Tsuchishima M, Tsutsumi M. Metabolism of N-nitrosodimethylamine, methylation of macromolecules, and development of hepatic fibrosis in rodent models. J Mol Med (Berl) 2020; 98:1203-13. [PMID: 32666246 DOI: 10.1007/s00109-020-01950-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/04/2020] [Accepted: 07/09/2020] [Indexed: 12/15/2022]
Abstract
Hepatic fibrosis and cirrhosis are chronic diseases affecting liver and a major health problem throughout the world. The hallmark of fibrosis and cirrhosis is inordinate synthesis and deposition of fibril forming collagens in the extracellular matrix of the liver leading to nodule formation and loss of normal architecture. Hepatic stellate cells play a crucial role in the pathogenesis and progression of liver fibrosis through secretion of several potent fibrogenic factors that trigger hepatocytes, portal fibrocytes, and bone marrow-derived fibroblasts to synthesize and deposit several connective tissue proteins, especially collagens between hepatocytes and space of Disse. Regulation of various events involved in the activation and transformation of hepatic stellate cells seems to be an appropriate strategy for the arrest of hepatic fibrosis and liver cirrhosis. In order to unravel the molecular mechanisms involved in the pathogenesis and progression of hepatic fibrosis, to determine proper and potent targets to arrest fibrosis, and to discover powerful therapeutic agents, a quick and reproducible animal model of hepatic fibrosis and liver cirrhosis that display all decompensating features of human condition is required. This review thoroughly evaluates the biochemical, histological, and pathological features of N-nitrosodimethylamine-induced model of liver injury, hepatic fibrosis, and early cirrhosis in rodents.
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Heck CS, Seneviratne HK, Bumpus NN. Twelfth-Position Deuteration of Nevirapine Reduces 12-Hydroxy-Nevirapine Formation and Nevirapine-Induced Hepatocyte Death. J Med Chem 2020; 63:6561-6574. [PMID: 32065749 PMCID: PMC7959450 DOI: 10.1021/acs.jmedchem.9b01990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Indexed: 01/08/2023]
Abstract
Cytochrome P450-dependent metabolism of the anti-HIV drug nevirapine (NVP) to 12-hydroxy-NVP (12-OHNVP) has been implicated in NVP toxicities. We investigated the impact of twelfth-position trideuteration (12-D3NVP) on the hepatic metabolism of and response to NVP. Formation of 12-OHNVP decreased in human (10.6-fold) and mouse (4.6-fold) hepatocytes incubated with 10 μM 12-D3NVP vs NVP. An observed kinetic isotope effect of 10.1 was measured in human liver microsomes. During mouse hepatocyte treatment (400 μM) with NVP or 12-D3NVP, cell death was reduced 30% with 12-D3NVP vs NVP, while glucuronidated and glutathione-conjugated metabolites increased with 12-D3NVP vs NVP. Using mass spectrometry proteomics, changes in hepatocyte protein expression, including an increase in stress marker insulin-like growth factor-binding protein 1 (IGFBP-1), were observed with 12-D3NVP vs NVP. These results demonstrate that while deuteration can reduce P450 metabolite formation, impacts on phase II metabolism and hepatocyte protein expression should be considered when employing deuteration to reduce P450 metabolite-related hepatotoxicity.
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Affiliation(s)
- Carley
J. S. Heck
- Department
of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Herana Kamal Seneviratne
- Department
of Medicine, Division of Clinical Pharmacology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Namandjé N. Bumpus
- Department
of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department
of Medicine, Division of Clinical Pharmacology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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16
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Abstract
Cytochrome P450 (P450) 2E1 is the major P450 enzyme involved in ethanol metabolism. That role is shared with two other enzymes that oxidize ethanol, alcohol dehydrogenase and catalase. P450 2E1 is also involved in the bioactivation of a number of low molecular weight cancer suspects, as validated in vivo in mouse models where cancers could be attenuated by deletion of Cyp2e1. P450 2E1 does not have a role in global production of reactive oxygen species but localized roles are possible, e.g. in mitochondria. The structures, conformations, and catalytic mechanisms of P450 2E1 have some unusual features among P450s. The concentration of hepatic P450 varies ≥10-fold among humans, possibly in part due to single nucleotide variants. The level of P450 2E1 may have relevance in the rates of oxidation of drugs, particularly acetaminophen and anesthetics.
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Affiliation(s)
- F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, 638 Robinson Research Building, 2200 Pierce Avenue, Nashville, TN, 37232-0146, USA.
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17
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Elbarbry F, Ung A, Rao D, Abdelkawy K. Effect of Dietary Doses of Quercetin on Hepatic Drug Metabolizing Enzymes in Spontaneously Hypertensive Rats. Eur J Drug Metab Pharmacokinet 2019; 44:761-70. [PMID: 31065969 DOI: 10.1007/s13318-019-00560-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Administration of quercetin (QR) has shown several health benefits in clinical and pre-clinical studies. OBJECTIVE This study investigates the effect of dietary doses of QR on hepatic drug metabolizing enzymes in spontaneously hypertensive rats in order to investigate the potential for herb-drug interactions. METHODS The activity and/or protein expression of selected cytochrome P450 (CYP) enzymes and microsomal epoxide hydrolase were measured in hepatic microsomes using specific probe substrates and/or polyclonal antibodies. Cytosolic fraction was utilized to measure protein level and activity of major antioxidant systems. RESULTS The doses employed in our study did not cause any significant alterations in the activity and/or protein level of CYP1A1, CYP2A6, CYP2E, and glutathione (GSH). While the activity and apoprotein levels of CYP1A2 and CYP2B1/2 were significantly reduced by the medium and high doses of QR, the activity and/or protein level of microsomal CYP3A and cytosolic GSH-S-transferase, GSH reductase, and GSH peroxidase were significantly enhanced. Activity and protein level of CYP2C9 were significantly inhibited by all doses. Only the high-dose QR resulted in significant inhibition of both microsomal and soluble epoxide hydrolase as well as induction of the antioxidant enzymes, catalase and superoxide dismutase. CONCLUSION This study demonstrates that dietary doses of QR may offer chemoprevention through stimulation of the endogenous antioxidant systems and inhibition of CYP enzymes involved in bioactivation of procarcinogens. However, modulation of drug metabolizing enzymes by QR could have potential for herb-drug interactions with the possibility of serious complications.
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Reddish MJ, Guengerich FP. Human cytochrome P450 11B2 produces aldosterone by a processive mechanism due to the lactol form of the intermediate 18-hydroxycorticosterone. J Biol Chem 2019; 294:12975-12991. [PMID: 31296661 DOI: 10.1074/jbc.ra119.009830] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/10/2019] [Indexed: 12/17/2022] Open
Abstract
Human cytochrome P450 (P450) 11B2 catalyzes the formation of aldosterone, the major endogenous human mineralocorticoid. Aldosterone is important for the regulation of electrolyte homeostasis. Mutations and overexpression of P450 11B2 (also known as aldosterone synthase) can lead to hypertension, congestive heart failure, and diabetic nephropathy. The enzyme is therefore a target for drug development to manage these various disorders. P450 11B2 catalyzes aldosterone formation from 11-deoxycorticosterone through three distinct oxidation steps. It is currently unknown to which degree these reactions happen in sequence without the intermediate products dissociating from the enzyme (i.e. processively) or whether these reactions happen solely distributively, in which the intermediate products must first dissociate and then rebind to the enzyme before subsequent oxidation. We present here a comprehensive investigation of processivity in P450 11B2-catalyzed reactions using steady-state, pre-steady-state, pulse-chase, equilibrium-binding titrations, and stopped-flow binding studies. We utilized the data obtained to develop a kinetic model for P450 11B2 and tested this model by enzyme kinetics simulations. We found that although aldosterone is produced processively, the enzyme preferentially utilizes a distributive mechanism that ends with the production of 18-OH corticosterone. This seemingly contradictory observation could be resolved by considering the ability of the intermediate product 18-OH corticosterone to exist as a lactol form, with the equilibrium favoring the ring-closed lactol configuration. In summary, our refined model for P450 11B2 catalysis indicates isomerization of the intermediate to a lactol can explain why P450 11B2 must produce aldosterone through a processive mechanism despite favoring a distributive mechanism.
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Affiliation(s)
- Michael J Reddish
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146.
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20
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Cox JA, Zwart EP, Luijten M, White PA. The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part I: Isolation, structural, genetic, and biochemical characterization. Environ Mol Mutagen 2019; 60:331-347. [PMID: 30592088 PMCID: PMC6590113 DOI: 10.1002/em.22253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/10/2018] [Accepted: 09/15/2018] [Indexed: 06/09/2023]
Abstract
To develop an improved in vitro mammalian cell gene mutation assay, it is imperative to address the known deficiencies associated with existing assays. Primary hepatocytes isolated from the MutaMouse are ideal for an in vitro gene mutation assay due to their metabolic competence, their "normal" karyotype (i.e., neither transformed nor immortalized), and the presence of the MutaMouse transgene for rapid and reliable mutation scoring. The cells were extensively characterized to confirm their utility. Freshly isolated cells were found to have a hepatocyte-like morphology, predominantly consisting of binucleated cells. These cells maintain hepatocyte-specific markers for up to 3 days in culture. Analyses revealed a normal murine hepatocyte karyotype with a modal ploidy number of 4n. Fluorescence in situ hybridization analysis confirmed the presence of the lambda shuttle vector on chromosome 3. The doubling time was determined to be 22.5 ± 3.3 h. Gene expression and enzymatic activity of key Phase I and Phase II metabolic enzymes were maintained for at least 8 and 24 h in culture, respectively. Exposure to β-naphthoflavone led to approximately 900- and 9-fold increases in Cyp1a1 and Cyp1a2 gene expression, respectively, and approximately twofold induction in cytochrome P450 (CYP) 1A1/1A2 activity. Exposure to phenobarbital resulted in an approximately twofold increase in CYP 2B6 enzyme activity. Following this characterization, it is evident that MutaMouse primary hepatocytes have considerable promise for in vitro mutagenicity assessment. The performance of these cells in an in vitro gene mutation assay is assessed in Part II. Environ. Mol. Mutagen. 60:331-347, 2019. © 2018 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Julie A. Cox
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOntarioCanada
| | - Edwin P. Zwart
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOntarioCanada
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21
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Cox JA, Zwart EP, Luijten M, White PA. The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part II: Assay performance for the identification of mutagenic chemicals. Environ Mol Mutagen 2019; 60:348-360. [PMID: 30714215 PMCID: PMC6593967 DOI: 10.1002/em.22277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/23/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
As demonstrated in Part I, cultured MutaMouse primary hepatocytes (PHs) are suitable cells for use in an in vitro gene mutation assay due to their metabolic competence, their "normal" phenotype, and the presence of the MutaMouse transgene for reliable mutation scoring. The performance of these cells in an in vitro gene mutation assay is evaluated in this study, Part II. A panel of 13 mutagenic and nonmutagenic compounds was selected to investigate the performance of the MutaMouse PH in vitro gene mutation assay. The nine mutagens represent a range of classes of chemicals and include mutagens that are both direct-acting and requiring metabolic activation. All the mutagens tested, except for ICR 191, elicited significant, concentration-dependent increases in mutant frequency (MF) ranging from 2.6- to 14.4-fold over the control. None of the four nonmutagens, including two misleading, or "false," positives (i.e., tertiary butylhydroquinone [TBHQ] and eugenol), yielded any significant increases in MF. The benchmark dose covariate approach facilitated ranking of the positive chemicals from most (i.e., 3-nitrobenzanthrone [3-NBA], benzo[a]pyrene [BaP], and aflatoxin B1 [AFB1]) to least (i.e., N-ethyl-N-nitrosourea [ENU]) potent. Overall, the results of this preliminary validation study suggest that this assay may serve as a complimentary tool alongside the standard genotoxicity test battery. This study, alongside Part I, illustrates the promise of MutaMouse PHs for use in an in vitro gene mutation assay, particularly for chemicals requiring metabolic activation. Environ. Mol. Mutagen. 60:348-360, 2019. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Julie A. Cox
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
| | - Edwin P. Zwart
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
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Jin G, Cai L, Hu K, Luo Y, Chen Y, Glatt H, Liu Y. Mutagenic Activity of N-Nitrosodiethylamine in Cell Lines Expressing Human CYP2E1-Adequacy of Dimethylsulfoxide as Solvent. Environ Mol Mutagen 2019; 60:214-226. [PMID: 30387191 DOI: 10.1002/em.22264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/14/2018] [Accepted: 10/26/2018] [Indexed: 06/08/2023]
Abstract
Human CYP2E1 metabolizes many xenobiotics of low-molecular weight, thereby activating various promutagens/procarcinogens. In toxicological studies in vitro, dimethylsulfoxide (DMSO) is a common vehicle for organic compounds. However, it was observed to potently inhibit CYP2E1 activity. We were interested in whether it affects CYP2E1-dependent mutagenic responses. In this study, N-nitrosodiethylamine (NDEA), which is soluble in both water and DMSO, was used as a model promutagen. It induced Hprt gene mutations and micronuclei in a Chinese hamster V79-derived cell line expressing both human CYP2E1 and sulfotransferase (SULT) 1A1 (V79-hCYP2E1-hSULT1A1) even at low-micromolar concentrations, but was inactive in parental V79 cells. Mutagenicity of NDEA was also observed in a recombinant V79-hCYP2E1 cell line that expresses human CYP2E1 at a lower level. NDEA induced micronuclei in human L-02 hepatocytes which expressed CYP2E1 even more weakly. DMSO did not modify NDEA-induced gene mutations or micronuclei, up to 0.2% (v:v, the highest noncytotoxic concentration) in V79-hCYP2E1-hSULT1A1 cells. In parental V79-Mz cells, NDEA induced micronuclei with Aroclor 1254-induced rat liver S9 mix, and this effect was unaffected by DMSO up to 0.2%. However, it inhibited the effect of NDEA in L-02 (by 44%) and V79-hCYP2E1 cells (by 70%) at 0.2%, with the effects of NDEA remaining statistically significant. No effect of DMSO was observed on CYP2E1 protein expression in V79-hCYP2E1-hSULT1A1 or its mRNA transcripts in each cell line. We conclude that DMSO may not significantly affect CYP2E1-dependent mutagenic effects, at concentrations up to 0.2% in cells with relatively high CYP2E1 expression. Environ. Mol. Mutagen. 60:214-226, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Guifang Jin
- Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Lu Cai
- Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Keqi Hu
- Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Yuyi Luo
- Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Yuting Chen
- Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Hansruedi Glatt
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany
- Department of Food Safety, Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Yungang Liu
- Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
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23
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George J, Tsutsumi M, Tsuchishima M. Alteration of Trace Elements during Pathogenesis of N-Nitrosodimethylamine Induced Hepatic Fibrosis. Sci Rep 2019; 9:708. [PMID: 30679730 PMCID: PMC6346110 DOI: 10.1038/s41598-018-37516-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/07/2018] [Indexed: 12/30/2022] Open
Abstract
The biochemical abnormalities and oxidative stress during pathogenesis of hepatic fibrosis could lead to alteration of trace elements. We studied the alteration of major trace elements during the pathogenesis of N-nitrosodimethylamine (NDMA)-induced hepatic fibrosis in rats. The biochemical and pathological indices of liver functions and hepatic fibrosis were evaluated. Serum and liver levels of copper, iron and zinc were determined using atomic absorption spectrophotometry. Cobalt, manganese, and molybdenum in the serum and liver were estimated by inductively coupled plasma mass spectrometry. Serial administrations of NDMA resulted in decreased serum albumin, biochemical abnormalities, increase of total liver collagen, and well-developed fibrosis and early cirrhosis. Serum and liver zinc content significantly decreased on all the days following NDMA administration. When copper and molybdenum markedly increased in the serum, liver molybdenum decreased dramatically. Both iron and manganese content significantly increased in the liver following NDMA-induced fibrosis. The results of the present study indicate that alteration of trace elements during pathogenesis of hepatic fibrosis is due to metabolic imbalance, biochemical abnormalities, decreased serum albumin, and ascites following NDMA-induced liver injury. The modulation of trace elements during hepatic fibrosis could play a prominent role in progression of the disease.
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Affiliation(s)
- Joseph George
- Department of Hepatology, Kanazawa Medical University, Uchinada, Ishikawa, 920-0293, Japan.
| | - Mikihiro Tsutsumi
- Department of Hepatology, Kanazawa Medical University, Uchinada, Ishikawa, 920-0293, Japan
| | - Mutsumi Tsuchishima
- Department of Hepatology, Kanazawa Medical University, Uchinada, Ishikawa, 920-0293, Japan
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George J, Tsuchishima M, Tsutsumi M. Molecular mechanisms in the pathogenesis of N-nitrosodimethylamine induced hepatic fibrosis. Cell Death Dis 2019; 10:18. [PMID: 30622238 PMCID: PMC6325159 DOI: 10.1038/s41419-018-1272-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/03/2018] [Accepted: 12/06/2018] [Indexed: 12/13/2022]
Abstract
Hepatic fibrosis is marked by excessive synthesis and deposition of connective tissue proteins, especially interstitial collagens in the extracellular matrix of the liver. It is a result of an abnormal wound healing in response to chronic liver injury from various causes such as ethanol, viruses, toxins, drugs, or cholestasis. The chronic stimuli involved in the initiation of fibrosis leads to oxidative stress and generation of reactive oxygen species that serve as mediators of molecular events involved in the pathogenesis of hepatic fibrosis. These processes lead to cellular injury and initiate inflammatory responses releasing a variety of cytokines and growth factors that trigger activation and transformation of resting hepatic stellate cells into myofibroblast like cells, which in turn start excessive synthesis of connective tissue proteins, especially collagens. Uncontrolled and extensive fibrosis results in distortion of lobular architecture of the liver leading to nodular formation and cirrhosis. The perpetual injury and regeneration process could also results in genomic aberrations and mutations that lead to the development of hepatocellular carcinoma. This review covers most aspects of the molecular mechanisms involved in the pathogenesis of hepatic fibrosis with special emphasize on N-Nitrosodimethylamine (NDMA; Dimethylnitorsmaine, DMN) as the inducing agent.
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Affiliation(s)
- Joseph George
- Division of Liver Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY, 10029, USA.
- Department of Hepatology, Kanazawa Medical University, Uchinada, Ishikawa, 920-0293, Japan.
| | - Mutsumi Tsuchishima
- Department of Hepatology, Kanazawa Medical University, Uchinada, Ishikawa, 920-0293, Japan
| | - Mikihiro Tsutsumi
- Department of Hepatology, Kanazawa Medical University, Uchinada, Ishikawa, 920-0293, Japan
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Abstract
Enzymes are complex biological catalysts and are critical to life. Most oxidations of chemicals are catalyzed by cytochrome P450 (P450, CYP) enzymes, which generally utilize mixed-function oxidase stoichiometry, utilizing pyridine nucleotides as electron donors: NAD(P)H + O2 + R → NAD(P)+ + RO + H2O (where R is a carbon substrate and RO is an oxidized product). The catalysis of oxidations is largely understood in the context of the heme iron-oxygen complex generally referred to as Compound I, formally FeO3+, whose basis was in peroxidase chemistry. Many X-ray crystal structures of P450s are now available (≥ 822 structures from ≥146 different P450s) and have helped in understanding catalytic specificity. In addition to hydroxylations, P450s catalyze more complex oxidations, including C-C bond formation and cleavage. Enzymes derived from P450s by directed evolution can even catalyze more unusual reactions, e.g. cyclopropanation. Current P450 questions under investigation include the potential role of the intermediate Compound 0 (formally FeIII-O2 -) in catalysis of some reactions, the roles of high- and low-spin forms of Compound I, the mechanism of desaturation, the roles of open and closed structures of P450s in catalysis, the extent of processivity in multi-step oxidations, and the role of the accessory protein cytochrome b 5. More global questions include exactly how structure drives function, prediction of catalysis, and roles of multiple protein conformations.
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Affiliation(s)
- F. Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
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26
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Abstract
Many oxidation-reduction (redox) enzymes, particularly oxygenases, have roles in reactions that make and break C-C bonds. The list includes cytochrome P450 and other heme-based monooxygenases, heme-based dioxygenases, nonheme iron mono- and dioxygenases, flavoproteins, radical S-adenosylmethionine enzymes, copper enzymes, and peroxidases. Reactions involve steroids, intermediary metabolism, secondary natural products, drugs, and industrial and agricultural chemicals. Many C-C bonds are formed via either (i) coupling of diradicals or (ii) generation of unstable products that rearrange. C-C cleavage reactions involve several themes: (i) rearrangement of unstable oxidized products produced by the enzymes, (ii) oxidation and collapse of radicals or cations via rearrangement, (iii) oxygenation to yield products that are readily hydrolyzed by other enzymes, and (iv) activation of O2 in systems in which the binding of a substrate facilitates O2 activation. Many of the enzymes involve metals, but of these, iron is clearly predominant.
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Affiliation(s)
- F Peter Guengerich
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232-0146 , United States.,Department of Chemistry , University of Texas-San Antonio , San Antonio , Texas 78249-0698 , United States
| | - Francis K Yoshimoto
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232-0146 , United States.,Department of Chemistry , University of Texas-San Antonio , San Antonio , Texas 78249-0698 , United States
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Li W, Yang Y, Qiao C, Zhang G, Luo Y. Functional characterization of phenylalanine ammonia-lyase- and cinnamate 4-hydroxylase-encoding genes from Lycoris radiata, a galanthamine-producing plant. Int J Biol Macromol 2018; 117:1264-1279. [PMID: 29894786 DOI: 10.1016/j.ijbiomac.2018.06.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 06/08/2018] [Accepted: 06/09/2018] [Indexed: 01/13/2023]
Abstract
Galanthamine (GAL), the well-known Amaryllidaceae alkaloid, is a clinically used drug for the treatment of Alzheimer's disease. L-Phenylalanine (Phe) and trans-cinnamic acid (CA) were enzymatically transformed into the catechol portion of GAL. Herein, a Phe ammonia-lyase-encoding gene LrPAL3 and a cinnamate 4-hydroxylase-encoding gene LrC4H were cloned from Lycoris radiata, a GAL-producing plant. LrPAL3 was overexpressed in Escherichia coli and purified to homogeneity. LrPAL3 catalyzes the forward deamination conversion of L-Phe into trans-CA. The 3-chloro- and 4-fluoro-L-Phe were deaminated to generate the corresponding 3-chloro- and 4-fluoro-trans-CA by LrPAL3. LrPAL3-catalyzed reverse hydroamination was confirmed by the conversion of trans-CA into L-Phe with exceptional regio- and stereo-selectivity. LrC4H was overexpressed in E. coli with tCamCPR, a cytochrome P450 reductase-encoding gene. LrC4H catalyzes the regioselective para-hydroxylation on trans-CA to form p-coumaric acid. The transcriptional levels of both LrPAL3 and LrC4H were positively associated with the GAL contents within the leaves and flowers of L. radiata, which suggested that their expression and function are co-regulated and involved in the biosynthesis of GAL. The present investigations on the biosynthetic genes of GAL will promote the development of synthetic biology platforms for this kind of important drug via metabolic engineering.
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Affiliation(s)
- Wei Li
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, 9 Section 4, Renmin Road South, Chengdu 610041, People's Republic of China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, People's Republic of China
| | - Yun Yang
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, 9 Section 4, Renmin Road South, Chengdu 610041, People's Republic of China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, People's Republic of China
| | - Chong Qiao
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, 9 Section 4, Renmin Road South, Chengdu 610041, People's Republic of China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, People's Republic of China
| | - Guolin Zhang
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, 9 Section 4, Renmin Road South, Chengdu 610041, People's Republic of China
| | - Yinggang Luo
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, 9 Section 4, Renmin Road South, Chengdu 610041, People's Republic of China; State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China.
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Zhao H, He H, Shi L, Cai X, Li H, Lan M, Zhang Q. Electrochemical detection of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone using a cytochrome P450 2E1 decorated biosensor. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.03.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Affiliation(s)
- Jens Atzrodt
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry; Industriepark Höchst, G876 65926 Frankfurt Deutschland
| | - Volker Derdau
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry; Industriepark Höchst, G876 65926 Frankfurt Deutschland
| | - William J. Kerr
- Department of Pure and Applied Chemistry, WestCHEM; University of Strathclyde; 295 Cathedral Street Glasgow Scotland G1 1XL Großbritannien
| | - Marc Reid
- Department of Pure and Applied Chemistry, WestCHEM; University of Strathclyde; 295 Cathedral Street Glasgow Scotland G1 1XL Großbritannien
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Atzrodt J, Derdau V, Kerr WJ, Reid M. Deuterium- and Tritium-Labelled Compounds: Applications in the Life Sciences. Angew Chem Int Ed Engl 2018; 57:1758-1784. [PMID: 28815899 DOI: 10.1002/anie.201704146] [Citation(s) in RCA: 391] [Impact Index Per Article: 65.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/27/2017] [Indexed: 12/19/2022]
Abstract
Hydrogen isotopes are unique tools for identifying and understanding biological and chemical processes. Hydrogen isotope labelling allows for the traceless and direct incorporation of an additional mass or radioactive tag into an organic molecule with almost no changes in its chemical structure, physical properties, or biological activity. Using deuterium-labelled isotopologues to study the unique mass-spectrometric patterns generated from mixtures of biologically relevant molecules drastically simplifies analysis. Such methods are now providing unprecedented levels of insight in a wide and continuously growing range of applications in the life sciences and beyond. Tritium (3 H), in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery. The efforts and costs associated with the synthesis of labelled compounds are more than compensated for by the enhanced molecular sensitivity during analysis and the high reliability of the data obtained. In this Review, advances in the application of hydrogen isotopes in the life sciences are described.
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Affiliation(s)
- Jens Atzrodt
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry, Industriepark Höchst, G876, 65926, Frankfurt, Germany
| | - Volker Derdau
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry, Industriepark Höchst, G876, 65926, Frankfurt, Germany
| | - William J Kerr
- Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, Scotland, G1 1XL, UK
| | - Marc Reid
- Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, Scotland, G1 1XL, UK
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Abstract
Cytochrome P450 (P450) enzymes are involved in the metabolism of carcinogens, as well as drugs, steroids, vitamins, and other classes of chemicals. P450s also oxidize ethanol, in particular P450 2E1. P450 2E1 oxidizes ethanol to acetaldehyde and then to acetic acid, roles also played by alcohol and aldehyde dehydrogenases. The role of P450 2E1 in cancer is complex in that P450 2E1 is also induced by ethanol, P450 2E1 is involved in the bioactivation and detoxication of a number of chemical carcinogens, and ethanol is an inhibitor of P450 2E1. Contrary to some literature, P450 2E1 expression and induction itself does not cause global oxidative stress in vivo, as demonstrated in studies using isoniazid treatment and gene deletion studies with rats and mice. However, a major fraction of P450 2E1 is localized in liver mitochondria instead of the endoplasmic reticulum, and studies with site-directed rat P450 2E1 mutants and natural human P450 2E1 N-terminal variants have shown that P450 2E1 localized in mitochondria is catalytically active and more proficient in producing reactive oxygen species and damage. The role of the mitochondrial oxidative stress in ethanol toxicity is still under investigation, as is the mechanism of altered electron transport to P450s that localize inside mitochondria instead of their typical endoplasmic reticulum environment.
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Li Z, Burnell DJ, Boyd RJ. Computational Study of Engineered Cytochrome P450-Catalyzed C–H Amination: The Origin of the Regio- and Stereoselectivity. J Phys Chem B 2017; 121:10859-10868. [DOI: 10.1021/acs.jpcb.7b10256] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Zhe Li
- Department of Chemistry, Dalhousie University,
P.O. Box 15000, Halifax, Nova Scotia B3H 4R2, Canada
| | - D. Jean Burnell
- Department of Chemistry, Dalhousie University,
P.O. Box 15000, Halifax, Nova Scotia B3H 4R2, Canada
| | - Russell J. Boyd
- Department of Chemistry, Dalhousie University,
P.O. Box 15000, Halifax, Nova Scotia B3H 4R2, Canada
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Carlson ES, Upadhyaya P, Hecht SS. A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s. J Vis Exp 2017. [PMID: 28994777 DOI: 10.3791/56312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
N-nitrosamines are a well-established group of environmental carcinogens, which require cytochrome P450 oxidation to exhibit activity. The accepted mechanism of metabolic activation involves formation of α-hydroxynitrosamines that spontaneously decompose to DNA alkylating agents. Accumulation of DNA damage and the resulting mutations can ultimately lead to cancer. New evidence indicates that α-hydroxynitrosamines can be further oxidized to nitrosamides processively by cytochrome P450s. Because nitrosamides are generally more stable than α-hydroxynitrosamines and can also alkylate DNA, nitrosamides may play a role in carcinogenesis. In this report, we describe a general protocol for evaluating nitrosamide production from in vitro cytochrome P450-catalyzed metabolism of nitrosamines. This protocol utilizes a general approach to the synthesis of the relevant nitrosamides and an in vitro cytochrome P450 metabolism assay using liquid chromatography-nanospray ionization-high resolution tandem mass spectrometry for detection. This method detected N'-nitrosonorcotinine as a minor metabolite of N'-nitrosonornicotine in the example study. The method has high sensitivity and selectively due to accurate mass detection. Application of this method to a wide variety of nitrosamine-cytochrome P450 systems will help determine the generality of this transformation. Because cytochrome P450s are polymorphic and vary in activity, a better understanding of nitrosamide formation could aid in individual cancer risk assessment.
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Affiliation(s)
- Erik S Carlson
- Department of Pharmacology, University of Minnesota; Masonic Cancer Center, University of Minnesota;
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Abstract
Cytochrome P450 (P450, CYP) research provides many opportunities for the application of kinetic isotope effect (KIE) strategies. P450s collectively catalyze oxidations of more substrates than any other group of enzymes, and CH bond cleavage is a major feature in a large fraction of these reactions. The presence of a significant primary deuterium KIE is evidence that hydrogen abstraction is at least partially rate-limiting in the reactions, and this appears to be the case in many P450 reactions. The first report of a KIE in (P450-linked) drug metabolism appeared in 1961 (for morphine N-demethylation), and in a number of cases, it has been possible to modulate the in vivo metabolism or toxicity of chemicals by deuterium substitution. A number of efforts are in progress to utilize deuterium substitution to alter the metabolism of drugs in an advantageous manner.
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Hossain M, Klobuchar AJ, Bartz JA. The photodissociation of N,N-dimethylnitrosamine at 355 nm: The effect of excited-state conformational changes on product vector correlations. J Chem Phys 2017; 147:013925. [PMID: 28688383 DOI: 10.1063/1.4982613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In a photodissociation experiment, the dynamics associated with creating reaction products with specific energies can be understood by a study of the product vector correlations. Upon excitation to the S1 state, N,N-dimethylnitrosamine (DMN) undergoes an excited-state geometry change from planar to pyramidal around the central N. The significant geometry change affects the vector correlations in the photoproducts. Using polarized lasers for 355 nm photodissociation of DMN and for NO photoproduct excitation in a velocity-mapped ion imaging apparatus reveals new vector correlation details among the parent transition dipole (μ), photofragment velocity (v), and photofragment angular momentum (j). The dissociation of DMN displays some μ-v correlation [β02(20)=-0.2], little μ-j correlation [β02(02)∼0], and, surprisingly, a v-j [β00(22)] correlation that depends on the NO lambda doublet probed. The results point to the importance of the initial excited-state conformational change and uncover the presence of two photolysis channels.
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Affiliation(s)
- Masroor Hossain
- Department of Chemistry, Kalamazoo College, 1200 Academy Street, Kalamazoo, Michigan 49006, USA
| | - Aidan J Klobuchar
- Department of Chemistry, Kalamazoo College, 1200 Academy Street, Kalamazoo, Michigan 49006, USA
| | - Jeffrey A Bartz
- Department of Chemistry, Kalamazoo College, 1200 Academy Street, Kalamazoo, Michigan 49006, USA
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Abstract
N'-Nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are carcinogenic tobacco-specific nitrosamines believed to play a vital role in the initiation of tobacco-related cancers. For their carcinogenicities to be exhibited, both NNN and NNK must be metabolically activated by cytochrome P450s, specifically P450 2A6 and P450 2A13, respectively. Prior research has focused on α-hydroxylation, which leads to the formation of several DNA adducts that have been identified and quantified in vivo. However, some studies indicate that P450s can retain substrates within their active sites and perform processive oxidation. For nitrosamines, this would oxidize the highly unstable α-hydroxynitrosamines to potentially more stable nitrosamides, which could also alkylate DNA. Thus, we hypothesized that both NNN and NNK are processively oxidized in vitro to nitrosamides by P450 2A6 and P450 2A13, respectively. To test this hypothesis, we synthesized the NNN- and NNK-derived nitrosamides, determined their half-lives at pH 7.4 and 37 °C, and monitored for nitrosamide formation in an in vitro P450 system with product analysis by LC/NSI+-HRMS/MS. Half-lives of the nitrosamides were determined by HPLC-UV and ranged from 7-35 min, which is more than 40 times longer than the corresponding α-hydroxynitrosamines. Incubation of NNN in the P450 2A6 system resulted in the formation of the nitrosamide N'-nitrosonorcotinine (NNC) at low levels. Similarly, the nitrosamide 4-(methylnitrosamino)-1-(3-pyridyl)-1,4-butanedione (CH2-oxo-NNK) was detected in low amounts in the incubation of NNK with the P450 2A13 system. The other possible NNK-derived nitrosamide, 4-(nitrosoformamido)-1-(3-pyridyl)-1-butanone (CH3-oxo-NNK), was not observed in the P450 2A13 reactions. CH2-oxo-NNK readily formed O6meGua in reactions with dGuo and calf thymus DNA. These results demonstrate that NNC and CH2-oxo-NNK are novel metabolites of NNN and NNK, respectively. Though low-forming, their increased stability may allow for mutagenic DNA damage in vivo. More broadly, this study provides the first account of a cytochrome P450-mediated conversion of nitrosamines to nitrosamides, which warrants further studies to determine how general this phenomenon is in nitrosamine metabolism.
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Affiliation(s)
- Erik S. Carlson
- Masonic Cancer Center, University of Minnesota, 2231 6 Street SE, 2-210 CCRB, Minneapolis, MN 55455, United States
- Department of Pharmacology, University of Minnesota Medical School, 321 Church Street SE, 6-120 Jackson Hall, Minneapolis, MN 55455
| | - Pramod Upadhyaya
- Masonic Cancer Center, University of Minnesota, 2231 6 Street SE, 2-210 CCRB, Minneapolis, MN 55455, United States
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, 2231 6 Street SE, 2-210 CCRB, Minneapolis, MN 55455, United States
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Yoshimoto FK, Gonzalez E, Auchus RJ, Guengerich FP. Mechanism of 17α,20-Lyase and New Hydroxylation Reactions of Human Cytochrome P450 17A1: 18O LABELING AND OXYGEN SURROGATE EVIDENCE FOR A ROLE OF A PERFERRYL OXYGEN. J Biol Chem 2016; 291:17143-64. [PMID: 27339894 DOI: 10.1074/jbc.m116.732966] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Indexed: 11/06/2022] Open
Abstract
Cytochrome P450 (P450) reactions can involve C-C bond cleavage, and several of these are critical in steroid and sterol biosynthesis. The mechanisms of P450s 11A1, 17A1, 19A1, and 51A1 have been controversial, in the context of the role of ferric peroxide (FeO2 (-)) versus perferryl (FeO(3+), compound I) chemistry. We reinvestigated the 17α-hydroxyprogesterone and 17α-hydroxypregnenolone 17α,20-lyase reactions of human P450 17A1 and found incorporation of one (18)O atom (from (18)O2) into acetic acid, consonant with proposals for a ferric peroxide mechanism (Akhtar, M., Lee-Robichaud, P., Akhtar, M. E., and Wright, J. N. (1997) J. Steroid Biochem. Mol. Biol. 61, 127-132; Akhtar, M., Wright, J. N., and Lee-Robichaud, P. (2011) J. Steroid Biochem. Mol. Biol. 125, 2-12). However, the reactions were supported by iodosylbenzene (a precursor of the FeO(3+) species) but not by H2O2 We propose three mechanisms that can involve the FeO(3+) entity and that explain the (18)O label in the acetic acid, two involving the intermediacy of an acetyl radical and one a steroid 17,20-dioxetane. P450 17A1 was found to perform 16-hydroxylation reactions on its 17α-hydroxylated products to yield 16,17α-dihydroxypregnenolone and progesterone, suggesting the presence of an active perferryloxo active species of P450 17A1 when its lyase substrate is bound. The 6β-hydroxylation of 16α,17α-dihydroxyprogesterone and the oxidation of both 16α,17α-dihydroxyprogesterone and 16α,17α-dihydroxypregnenolone to 16-hydroxy lyase products were also observed. We provide evidence for the contribution of a compound I mechanism, although contribution of a ferric peroxide pathway in the 17α,20-lyase reaction cannot be excluded.
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Affiliation(s)
- Francis K Yoshimoto
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146 and the Division of Metabolism, Diabetes and Endocrinology, Departments of Internal Medicine and Pharmacology, University of Michigan, Ann Arbor, Michigan 48019
| | - Eric Gonzalez
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146 and
| | - Richard J Auchus
- the Division of Metabolism, Diabetes and Endocrinology, Departments of Internal Medicine and Pharmacology, University of Michigan, Ann Arbor, Michigan 48019
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146 and
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Ambade A, Satishchandran A, Gyongyosi B, Lowe P, Szabo G. Adult mouse model of early hepatocellular carcinoma promoted by alcoholic liver disease. World J Gastroenterol 2016; 22:4091-108. [PMID: 27122661 PMCID: PMC4837428 DOI: 10.3748/wjg.v22.i16.4091] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/09/2016] [Accepted: 03/18/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To establish a mouse model of alcohol-driven hepatocellular carcinoma (HCC) that develops in livers with alcoholic liver disease (ALD). METHODS Adult C57BL/6 male mice received multiple doses of chemical carcinogen diethyl nitrosamine (DEN) followed by 7 wk of 4% Lieber-DeCarli diet. Serum alanine aminotransferase (ALT), alpha fetoprotein (AFP) and liver Cyp2e1 were assessed. Expression of F4/80, CD68 for macrophages and Ly6G, MPO, E-selectin for neutrophils was measured. Macrophage polarization was determined by IL-1β/iNOS (M1) and Arg-1/IL-10/CD163/CD206 (M2) expression. Liver steatosis and fibrosis were measured by oil-red-O and Sirius red staining respectively. HCC development was monitored by magnetic resonance imaging, confirmed by histology. Cellular proliferation was assessed by proliferating cell nuclear antigen (PCNA). RESULTS Alcohol-DEN mice showed higher ALTs than pair fed-DEN mice throughout the alcohol feeding without weight gain. Alcohol feeding resulted in increased ALT, liver steatosis and inflammation compared to pair-fed controls. Alcohol-DEN mice had reduced steatosis and increased fibrosis indicating advanced liver disease. Molecular characterization showed highest levels of both neutrophil and macrophage markers in alcohol-DEN livers. Importantly, M2 macrophages were predominantly higher in alcohol-DEN livers. Magnetic resonance imaging revealed increased numbers of intrahepatic cysts and liver histology confirmed the presence of early HCC in alcohol-DEN mice compared to all other groups. This correlated with increased serum alpha-fetoprotein, a marker of HCC, in alcohol-DEN mice. PCNA immunostaining revealed significantly increased hepatocyte proliferation in livers from alcohol-DEN compared to pair fed-DEN or alcohol-fed mice. CONCLUSION We describe a new 12-wk HCC model in adult mice that develops in livers with alcoholic hepatitis and defines ALD as co-factor in HCC.
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MESH Headings
- Alanine Transaminase/blood
- Animals
- Biomarkers, Tumor/blood
- Carcinoma, Hepatocellular/blood
- Carcinoma, Hepatocellular/etiology
- Carcinoma, Hepatocellular/pathology
- Cell Proliferation
- Cytochrome P-450 CYP2E1/metabolism
- Diethylnitrosamine
- Endotoxins/blood
- Ethanol
- Fatty Liver, Alcoholic/blood
- Fatty Liver, Alcoholic/complications
- Fatty Liver, Alcoholic/pathology
- Hepatocytes/metabolism
- Hepatocytes/pathology
- Immunohistochemistry
- Liver Cirrhosis, Alcoholic/blood
- Liver Cirrhosis, Alcoholic/complications
- Liver Cirrhosis, Alcoholic/pathology
- Liver Neoplasms, Experimental/blood
- Liver Neoplasms, Experimental/chemically induced
- Liver Neoplasms, Experimental/etiology
- Liver Neoplasms, Experimental/pathology
- Macrophage Activation
- Macrophages/metabolism
- Macrophages/pathology
- Magnetic Resonance Imaging
- Male
- Mice, Inbred C57BL
- Neutrophil Infiltration
- Neutrophils/metabolism
- Neutrophils/pathology
- Phenotype
- Time Factors
- alpha-Fetoproteins/metabolism
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Ambade A, Satishchandran A, Szabo G. Alcoholic hepatitis accelerates early hepatobiliary cancer by increasing stemness and miR-122-mediated HIF-1α activation. Sci Rep 2016; 6:21340. [PMID: 26888602 DOI: 10.1038/srep21340] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/26/2015] [Indexed: 12/12/2022] Open
Abstract
Alcohol-related hepatocellular carcinoma (HCC) develops with advanced alcoholic liver disease and liver fibrosis. Using adult mice, we evaluate the effect of alcoholic steatohepatitis on early hepatobiliary carcinoma after initiation by diethyl-nitrosamine (DEN). Here we show that alcohol-fed DEN-injected mice have higher ALT and liver-to-body weight ratio compared to pair-fed DEN-injected mice. Alcohol feeding results in steatohepatitis indicated by increased pro-inflammatory cytokines and fibrotic genes. MRI and liver histology of alcohol+DEN mice shows hepatobiliary cysts, early hepatic neoplasia and increase in serum alpha-fetoprotein. Proliferation makers (BrdU, cyclin D1, p53) and cancer stem cell markers (CD133 and nanog) are significantly up-regulated in livers of alcohol-fed DEN-injected mice compared to controls. In livers with tumors, loss of miR-122 expression with a significant up-regulation of miR-122 target HIF-1α is seen. We conclude that alcoholic steatohepatitis accelerates hepatobiliary tumors with characteristic molecular features of HCC by up-regulating inflammation, cell proliferation, stemness, and miR-122 loss.
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Amin A, CanGongora M, Elbarbry F. Dietary Doses of Sulforaphane Affect Hepatic Drug Metabolizing Enzymes in Spontaneously Hypertensive Rats. Phytother Res 2015; 29:1412-1420. [PMID: 26084424 DOI: 10.1002/ptr.5397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/15/2015] [Accepted: 05/22/2015] [Indexed: 11/08/2022]
Abstract
We previously demonstrated that exposure of spontaneously hypertensive rats (SHR) to dietary doses of sulforaphane (SF) results in resisting the progressive rise in blood pressure that is normally seen in these rats. This study investigates the potential effect of SF on hepatic drug metabolizing enzymes (DME) in SHR. The activity and/or protein expression of selected cytochrome P450 (CYP) enzymes and microsomal epoxide hydrolase (mEH) were measured in hepatic microsomes using specific probe substrates and/or polyclonal antibodies. Cytosolic fraction was utilized to measure protein level and activity of major antioxidant systems. The high dose SF resulted in a significant reduction of activity and apoproteins level of CYP1A2 and CYP2C9 and activities of CYP2B1/2 and mEH. No effect of SF was observed on the rest of the studied CYP enzymes. Both doses of SF resulted in a significant induction of both hepatic glutathione level and activities of superoxide dismutase and catalase. Activities of hepatic glutathione-S-transferases, glutathione reductase, and glutathione peroxidase were significantly induced only with the high dose. This study demonstrates that dietary doses of SF modulate the activity or protein expression of DME. Additionally, induction of the impaired antioxidant system in SHR may explain the blood pressure lowering effect of SF in this rat model. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Anik Amin
- School of Pharmacy, Pacific University, Hillsboro, OR, 97123, USA
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Abstract
Cytochromes P450 (CYPs) are a large group of hemeproteins located on mitochondrial membranes or the endoplasmic reticulum. They play a crucial role in the metabolism of endogenous and exogenous molecules. The activity of CYP is associated with a number of factors including redox potential, protein conformation, the accessibility of the active site by substrates, and others. This activity may be potentially modulated by a variety of small molecules. Extensive experimental data collected over the past decade point at the active role of natural polyphenols in modulating the catalytic activity of CYP. Polyphenols are widespread micronutrients present in human diets of plant origin and in medicinal herbs. These compounds may alter the activity of CYP either via direct interactions with the enzymes or by affecting CYP gene expression. The polyphenol-CYP interactions may significantly alter the pharmacokinetics of drugs and thus influence the effectiveness of chemical therapies used in the treatment of different types of cancers, diabetes, obesity, and cardiovascular diseases (CVD). CYPs are involved in the oxidation and activation of external carcinogenic agents, in which case the inhibition of the CYP activity is beneficial for health. CYPs also support detoxification processes. In this case, it is the upregulation of CYP genes that would be favorable for the organism. A CYP enzyme aromatase catalyzes the formation of estrone and estradiol from their precursors. CYPs also catalyze multiple reactions leading to the oxidation of estrogen. Estrogen signaling and oxidative metabolism of estrogen are associated with the development of cancer. Thus, polyphenol-mediated modulation of the CYP's activity also plays a vital role in estrogen carcinogenesis. The aim of the present review is to summarize the data collected over the last five to six years on the following topics: (1) the mechanisms of the interactions of CYP with food constituents that occur via the direct binding of polyphenols to the enzymes and (2) the mechanisms of the regulation of CYP gene expression mediated by polyphenols. The structure-activity relationship relevant to the ability of polyphenols to affect the activity of CYP is analyzed. The application of polyphenol-CYP interactions to diseases is discussed.
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Affiliation(s)
- Ekaterina A Korobkova
- John Jay College of Criminal Justice, The Department of Sciences, City University of New York, 524 W 59th Street, New York, New York 10019, United States
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Bopp A, Wartlick F, Henninger C, Schwarz M, Kaina B, Fritz G. Rac1 promotes diethylnitrosamine (DEN)-induced formation of liver tumors. Carcinogenesis 2015; 36:378-89. [PMID: 25556150 DOI: 10.1093/carcin/bgu323] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To elucidate the function of the Ras-homologous GTPase Rac1 in hepatocarcinogenesis induced by diethylnitrosamine (DEN), mice lacking hepatic Rac1 expression were treated with DEN and compared to the wild-type (WT). Rac1 knock-out (KO) mice were found to have a lower tumor yield as compared to Rac1 proficient mice. The small-sized tumors formed in the absence of Rac1 lack an activated Ras/Raf/mitogen-activated protein kinase pathway, as indicated by the absence of p-ERK expression. Apparently, Rac1 is required for Ras-driven oncogenic pathways. Moreover, tumors in Rac1 deficient mice were glutamine synthase (GS) negative. They displayed a high number of p-H3-positive and cyclinB1 expressing cells, pointing to a defect in mitotic progression. To elucidate the influence of Rac1 on mechanisms of tumor initiation, acute DEN-induced hepatic stress responses were monitored. Rac1 deficiency caused fairly complex, partially time-dependent, alterations in both basal and/or DEN-induced messenger RNA (mRNA) and protein levels of susceptibility-related genes. Basal protein expression of DNA repair factors Brca1 and DNA repair protein RAD51 homolog (Rad51) and the cell cycle regulatory factor p27 was enhanced in the absence of Rac1. Following DEN treatment, p21 mRNA and protein expression was stimulated independent of the Rac1 status. Lack of Rac1 increased mechanisms of the DNA damage response (DDR), as shown by elevated protein levels of p-ATR, p-p53 and γH2AX 24h after DEN treatment. The data show that Rac1 is essential for DEN-stimulated hepatocarcinogenesis. We hypothesize that it promotes tumor initiation by counteracting the elimination of initiated cells and, moreover, alleviates the outgrowth of transformed cells. Hence, pharmacological targeting of Rac1 could be suitable for chemoprevention.
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Affiliation(s)
- Anita Bopp
- Institute of Toxicology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany
| | - Friedrich Wartlick
- Institute of Toxicology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany
| | - Christian Henninger
- Institute of Toxicology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany
| | - Michael Schwarz
- Institute of Pharmacology and Toxicology, University Tübingen, Wilhelmstrasse 76, D-72074 Tübingen, Germany
| | - Bernd Kaina
- Institute of Toxicology, University Medical Center Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany and
| | - Gerhard Fritz
- Institute of Toxicology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany,
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Pallan PS, Nagy LD, Lei L, Gonzalez E, Kramlinger VM, Azumaya CM, Wawrzak Z, Waterman MR, Guengerich FP, Egli M. Structural and kinetic basis of steroid 17α,20-lyase activity in teleost fish cytochrome P450 17A1 and its absence in cytochrome P450 17A2. J Biol Chem 2014; 290:3248-68. [PMID: 25533464 DOI: 10.1074/jbc.m114.627265] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytochrome P450 (P450) 17A enzymes play a critical role in the oxidation of the steroids progesterone (Prog) and pregnenolone (Preg) to glucocorticoids and androgens. In mammals, a single enzyme, P450 17A1, catalyzes both 17α-hydroxylation and a subsequent 17α,20-lyase reaction with both Prog and Preg. Teleost fish contain two 17A P450s; zebrafish P450 17A1 catalyzes both 17α-hydroxylation and lyase reactions with Prog and Preg, and P450 17A2 is more efficient in pregnenolone 17α-hydroxylation but does not catalyze the lyase reaction, even in the presence of cytochrome b5. P450 17A2 binds all substrates and products, although more loosely than P450 17A1. Pulse-chase and kinetic spectral experiments and modeling established that the two-step P450 17A1 Prog oxidation is more distributive than the Preg reaction, i.e. 17α-OH product dissociates more prior to the lyase step. The drug orteronel selectively blocked the lyase reaction of P450 17A1 but only in the case of Prog. X-ray crystal structures of zebrafish P450 17A1 and 17A2 were obtained with the ligand abiraterone and with Prog for P450 17A2. Comparison of the two fish P450 17A-abiraterone structures with human P450 17A1 (DeVore, N. M., and Scott, E. E. (2013) Nature 482, 116-119) showed only a few differences near the active site, despite only ∼50% identity among the three proteins. The P450 17A2 structure differed in four residues near the heme periphery. These residues may allow the proposed alternative ferric peroxide mechanism for the lyase reaction, or residues removed from the active site may allow conformations that lead to the lyase activity.
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Affiliation(s)
- Pradeep S Pallan
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Leslie D Nagy
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Li Lei
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Eric Gonzalez
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Valerie M Kramlinger
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Caleigh M Azumaya
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Zdzislaw Wawrzak
- the Life Sciences Collaborative Access Team, Sector 21, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439
| | - Michael R Waterman
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Martin Egli
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
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Thiedemann B, Schmitz CML, Staubitz A. Reduction of N-Allylamides by LiAlH4: Unexpected Attack of the Double Bond with Mechanistic Studies of Product and Byproduct Formation. J Org Chem 2014; 79:10284-95. [DOI: 10.1021/jo501907v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Birk Thiedemann
- Otto-Diels-Institute
for
Organic Chemistry, University of Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
| | - Christin M. L. Schmitz
- Otto-Diels-Institute
for
Organic Chemistry, University of Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
| | - Anne Staubitz
- Otto-Diels-Institute
for
Organic Chemistry, University of Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
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45
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Tao F, Dai Y, Wang C, Feng G, Li D, Ma K, Zhu L, Tan L, Yu X. The interaction of a cobalt porphyrin with cancer-associated nitrosamines. Bioorg Chem 2014; 56:67-74. [PMID: 25123542 DOI: 10.1016/j.bioorg.2014.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 07/18/2014] [Accepted: 07/23/2014] [Indexed: 11/24/2022]
Abstract
A cobalt porphyrin (CY-B) was presented, and its interaction with tobacco-specific nitrosamines (TSNAs) was investigated by UV-Vis spectroscopy and high-resolution mass spectrometry. The results revealed that the stoichiometry of the host-guest interaction was 1:2 and that the binding constant between CY-B and TSNAs was within the range of 0.78×10(8)-7.83×10(8)M(-2). The coordination strength between CY-B and TSNAs decreased in the sequence of NNN>NAB>NAT>NNK based on the binding constant. The interaction mechanism of CY-B with TSNAs involved a coordination interaction, and the π-π interaction between the porphyrin macrocycle and the aromatic frame of the TSNAs pyridines may also have been a driving force. The measured thermodynamic properties demonstrated that the reaction of CY-B with TSNAs was spontaneous and that the driving force for the interaction was a change in enthalpy. The reaction was exothermic, and an increasing temperature inhibited the interaction. The IR spectrum of the complex revealed that the NNO group of TSNAs and the metal cobalt of CY-B formed the six-coordinate complex.
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Affiliation(s)
- Feiyan Tao
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China; Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Ya Dai
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China.
| | - Changguo Wang
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Guanglin Feng
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Dongliang Li
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Kuoyan Ma
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Lijun Zhu
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Lanlan Tan
- Harmful Components and Tar Reduction in Cigarette, Sichuan Key Laboratory Technical Research Center, Chuanyu Branch of China Tobacco Corporation, Chengdu 610066, China
| | - Xiaoqi Yu
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
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46
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Zbib N, Repussard C, Tardieu D, Priymenko N, Domange C, Guerre P. Ergovaline in tall fescue and its effect on health, milk quality, biochemical parameters, oxidative status, and drug metabolizing enzymes of lactating ewes. J Anim Sci 2014; 92:5112-23. [PMID: 25253811 DOI: 10.2527/jas.2014-8106] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ergovaline (EV) produced by symbiotic association of Epichloë coenophiala with tall fescue (Lolium arundinaceum) causes toxicoses in livestock. In this study, 16 lactating ewes (BW 76.0 ± 0.6 kg) were used to determine the effects of feeding endophyte-infected (FE+) or endophyte free (FE-) tall fescue hay on animal health and performances and to investigate the putative mechanisms of action of EV. The mean EV concentrations in FE+ and FE- diets were 497 ± 52 and <5 µg/kg DM, respectively. Decreased hay consumption and BW were observed in the FE+ group. Prolactin (PRL) concentrations decreased (P < 0.02) in the FE+ group from d 3 to 28 of the study compared to the FE- group, but no consequences were observed on milk quantity or quality. Skin temperature and the thermocirculation index were lower (P < 0.05) in the FE+ than in the FE- group from d 3 to 7, but this effect disappeared from d 14 to 28. Hematocrit, mineral and biochemical, and enzymatic analyses of plasma revealed no differences between the 2 groups. Measurement of oxidative damage and antioxidant enzyme activities revealed a decrease in the activities of plasma catalase (P < 0.05), kidney glutathione reductase and peroxidase and in kidney total glutathione and malondialdehyde contents (P < 0.02) in ewes fed FE+. Hepatic flavin monooxygenase enzyme activities decreased (P < 0.01) in ewes fed FE+, except for a marked increase in the demethylation of erythromycin. This activity is linked to cytochrome P4503A content and is known to be involved in ergot alkaloid metabolism. Glutathione S-transferase activity in the kidneys decreased (P < 0.02) in the FE+ group, whereas no difference was observed in uridine diphosphate-glucuronosyltransferase activity in the liver or kidneys. The reversibility of the effect of FE+ hay on skin temperature and the increase in erythromycin N-demethylase activity may contribute to the relative resistance of ewes to EV toxicity.
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Affiliation(s)
- N Zbib
- Université de Toulouse, INP, ENVT, UR Mycotoxicologie, F-31076 Toulouse, France
| | - C Repussard
- Université de Toulouse, INP, ENVT, UR Mycotoxicologie, F-31076 Toulouse, France
| | - D Tardieu
- Université de Toulouse, INP, ENVT, UR Mycotoxicologie, F-31076 Toulouse, France
| | - N Priymenko
- Université de Toulouse, INP, ENVT, INRA UMR1331 Toxalim, F-31076 Toulouse France
| | - C Domange
- Université de Toulouse, INP, ENVT, INRA UMR1331 Toxalim, F-31076 Toulouse France
| | - P Guerre
- Université de Toulouse, INP, ENVT, UR Mycotoxicologie, F-31076 Toulouse, France
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47
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Atzrodt J, Derdau V. Selected scientific topics of the 11th International Isotope Symposium on the Synthesis and Applications of Isotopes and Isotopically Labeled Compounds. J Labelled Comp Radiopharm 2013; 56:408-16. [PMID: 24285513 DOI: 10.1002/jlcr.3096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/19/2013] [Accepted: 06/19/2013] [Indexed: 01/02/2023]
Abstract
This micro-review describes hot topics and new trends in isotope science discussed at the 11th International Isotope Symposium on the Synthesis and Applications of Isotopes and Isotopically Labeled Compounds from a personal perspective.
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Affiliation(s)
- Jens Atzrodt
- Isotope Chemistry & Metabolite Synthesis, DSAR-DD, Sanofi-Aventis Deutschland GmbH, Industriepark Höchst G876, 65926, Frankfurt am Main, Germany
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48
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Guengerich FP. Kinetic deuterium isotope effects in cytochrome P450 oxidation reactions. J Labelled Comp Radiopharm 2013; 56:428-31. [PMID: 24285515 DOI: 10.1002/jlcr.3031] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/08/2013] [Accepted: 01/14/2013] [Indexed: 11/09/2022]
Abstract
Cytochrome P450 (P450) enzymes account for ~75% of the metabolism of drugs. Most of the reactions catalyzed by P450s are mixed-function oxidations, and a C-H bond is (usually) broken. The rate-limiting nature of this step can be analyzed using the kinetic isotope effect (KIE) approach. The most relevant type of KIE is one termed intermolecular non-competitive, indicative of rate-limiting C-H bond breaking. A plot of KIE versus kcat for several P450s showed a correlation coefficient (r(2) ) of 0.62. Deuterium substitution has been considered as a potential means of slowing drug metabolism or redirecting sites of metabolism in some cases, and several general points can be made regarding the potential for application of deuterium in drug design/development based on what is known about P450 KIEs.
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Affiliation(s)
- F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
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