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Mata DA, Lee JK, Shanmugam V, Marcus CB, Schrock AB, Williams EA, Ritterhouse LL, Hickman RA, Janovitz T, Patel NR, Kroger BR, Ross JS, Mirza KM, Oxnard GR, Vergilio JA, Elvin JA, Benhamida JK, Decker B, Xu ML. Liquid biopsy-based circulating tumour (ct)DNA analysis of a spectrum of myeloid and lymphoid malignancies yields clinically actionable results. Histopathology 2024; 84:1224-1237. [PMID: 38422618 DOI: 10.1111/his.15168] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 03/02/2024]
Abstract
AIMS Liquid biopsy (LBx)-based next-generation sequencing (NGS) of circulating tumour DNA (ctDNA) can facilitate molecular profiling of haematopoietic neoplasms (HNs), particularly when tissue-based NGS is infeasible. METHODS AND RESULTS We studied HN LBx samples tested with FoundationOne Liquid CDx, FoundationOne Liquid, or FoundationACT between July 2016 and March 2022. We identified 271 samples: 89 non-Hodgkin lymphoma (NHL), 43 plasma-cell neoplasm (PCN), 41 histiocytoses, 27 myelodysplastic syndrome (MDS), 25 diffuse large B-cell lymphoma (DLBCL), 22 myeloproliferative neoplasm (MPN), 14 Hodgkin lymphoma (HL), and 10 acute myeloid leukaemia (AML). Among 73.4% with detectable pathogenic alterations, median maximum somatic allele frequency (MSAF) was 16.6%, with AML (36.2%), MDS (19.7%), and MPN (44.5%) having higher MSAFs than DLBCL (3.9%), NHL (8.4%), HL (1.5%), PCN (2.8%), and histiocytoses (1.8%) (P = 0.001). LBx detected characteristic alterations across HNs, including in TP53, KRAS, MYD88, and BTK in NHLs; TP53, KRAS, NRAS, and BRAF in PCNs; IGH in DLBCL; TP53, ATM, and PDCD1LG2 in HL; BRAF and MAP2K1 in histiocytoses; TP53, SF3B1, DNMT3A, TET2, and ASXL1 in MDS; JAK2 in MPNs; and FLT3, IDH2, and NPM1 in AML. Among 24 samples, the positive percent agreement by LBx was 75.7% for variants present in paired buffy coat, marrow, or tissues. Also, 75.0% of pairs exhibited alterations only present on LBx. These were predominantly subclonal (clonal fraction of 3.8%), reflecting the analytical sensitivity of LBx. CONCLUSION These data demonstrate that LBx can detect relevant genomic alterations across HNs, including at low clonal fractions, suggesting a potential clinical utility for identifying residual or emerging therapy-resistant clones that may be undetectable in site-specific tissue biopsies.
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Affiliation(s)
| | | | - Vignesh Shanmugam
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | | | - Erik A Williams
- Foundation Medicine, Inc., Cambridge, MA, USA
- Department of Pathology and Laboratory Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | | | | | | | - Benjamin R Kroger
- Division of Hematology/Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey S Ross
- Foundation Medicine, Inc., Cambridge, MA, USA
- Departments of Pathology, Urology, and Medicine (Oncology), State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kamran M Mirza
- Department of Pathology, Michigan Medicine, Ann Arbor, MI, USA
| | | | | | | | - Jamal K Benhamida
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Mina L Xu
- Department of Pathology, Yale New-Haven Hospital, Yale School of Medicine, New Haven, CT, USA
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2
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Vidal JD, Vandevoort CA, Marcus CB, Lazarewicz NR, Conley AJ. 2,3,7,8-Tetrachlorodibenzo-p-dioxin induces CYP1B1 expression in human luteinized granulosa cells. Arch Biochem Biophys 2005; 439:53-60. [PMID: 15953582 DOI: 10.1016/j.abb.2005.04.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Revised: 04/28/2005] [Accepted: 04/29/2005] [Indexed: 10/25/2022]
Abstract
The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a reproductive toxicant in multiple species; however, mechanisms and direct ovarian effects are poorly understood. DNA microarrays were used to characterize gene expression profiles of human luteinized granulosa cells (HLGCs) exposed to TCDD in primary cultures. Exposure to 10 nM TCDD for 24 h induced a significant increase in CYP1B1, while few other genes responded. TaqMan PCR and Western immunoblotting demonstrated that induction was dose-dependent. Additionally, the microsomal form of catechol-O-methyltransferase (COMT) was highly expressed in HLGCs, along with only fractional amounts of the soluble form. This is the first report of CYP1B1 and COMT expression, and CYP1B1 induction, in cells from the human ovary. The role of CYP1B1 in the oxidative metabolism of estrogens and potential generation of DNA adducts in the ovary may have significant consequences for oocyte quality, corpus luteum function, and ovarian carcinogenesis.
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Affiliation(s)
- J D Vidal
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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3
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Abstract
This review presents a brief and non-comprehensive overview of a representative sampling of some of the broad array of toxicology-related learning, tutorial and information resources now becoming widely available to educators, health professionals, students and the general public in digital media and/or via the Internet. A broad variety of useful learning and reference resources in the general fields of toxicology and the environmental health sciences is provided to introduce the reader to the diverse types of information currently available. The sources and Internet links contained in this review will hopefully constitute a useful resource of basic toxicology information that should be readily accessible to most if not all readers.
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Affiliation(s)
- J F Sharpe
- University of Washington, Center for Ecogenetics and Environmental Health, Seattle, WA 98105-6099, USA.
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4
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Sidhu JS, Marcus CB, Parkinson A, Omiecinski CJ. Differential induction of cytochrome P450 gene expression by 4n-alkyl-methylenedioxybenzenes in primary rat hepatocyte cultures. J Biochem Mol Toxicol 2000; 12:253-62. [PMID: 9664231 DOI: 10.1002/(sici)1099-0461(1998)12:5<253::aid-jbt1>3.0.co;2-k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A well-characterized primary rat hepatocyte culture system was used to examine induction patterns of cytochrome 450 gene expression by a series of 4-n-alkyl-methylenedioxybenzene (MDBs) derivatives. Hepatocytes were treated for 24, 48, or 72 hours with 0-500 microM of the MDB compounds, and total cellular RNA and protein from each treatment was evaluated by hybridization and immunochemical techniques. Exposure to MDB congeners possessing increasing 4-n-alkyl side-chain length (C0-C8) resulted in dose- and structure-dependent activation of CYP2B1, 2B2, 3A1, 1A1, and 1A2 gene expression. At equivalent 100 microM concentrations, the C6 and C8 MDB congeners were more effective than the prototypical inducer phenobarbital (PB) with respect to induction potency of CYP2B1, CYP2B2, and CYP3A1 gene expression. In contrast to PB, longer side-chain-substituted MDBs effectively induced CYP1A1 and CYP1A2 gene expression, in addition to the CYP2B and CYP3A genes. At equivalent molar concentrations, the catechol derivative of C6-MDB was ineffective in its ability to induce CYP gene expression, indicating the importance of the intact methylenedioxy bridge in the induction mechanism. Levels of MDB-inducible CYP2B1 and CYP2B2 mRNA were highly correlated with CYP2B1/2 apoprotein levels, ascertained by immunoblot analysis of cultured hepatocyte S9 fractions. Compared with results from previous in vivo analysis (12), the current data indicate that pharmacodynamic factors may influence MDB induction profiles and that differences in MDB effects on CYP gene expression result depending on distinct structure-activity relationships.
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Affiliation(s)
- J S Sidhu
- Department of Environmental Health, University of Washington, Seattle 98105-6099, USA
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5
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Scharf ME, Neal JJ, Marcus CB, Bennett GW. Cytochrome P450 purification and immunological detection in an insecticide resistant strain of German cockroach (Blattella germanica, L.). Insect Biochem Mol Biol 1998; 28:1-9. [PMID: 9612934 DOI: 10.1016/s0965-1748(97)00060-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A German cockroach strain, Munsyana (MA) had 80-fold resistance to the pyrethroid insecticide cypermethrin, 4.5-fold greater total cytochrome P450 content and 2.5-fold greater cytochrome P450-mediated N-demethylation of 4-chloro-N-methylaniline compared to the susceptible Johnson Wax (JWax) strain. Immobilized artificial membrane high performance liquid chromatography (IAM-HPLC) of microsomal proteins from the MA strain enriched cytochrome P450 greater than 70-fold. Following purification, a single protein band of M(r) = 49,000 (P450 MA), was detected by silver-staining SDS PAGE gels. Antiserum to the purified protein from the MA strain (anti-P450 MA) was produced in mice. Anti-P450 MA inhibited cytochrome P450-mediated N-demethylation by 4-fold in both MA and JWax strains. In Western blots of microsomal proteins, anti-P450 MA differentiated single MA and JWax individuals by recognizing and M(r) 49,000 protein band in only the MA strain. In JWax cockroaches, the M(r) 49,000 band was only detectable in Western analysis following induction with pentamethylbenzene (PMB). PMB induction also increases N-demethylation 2.6 and 8.0-fold in the MA and JWax strains, respectively. These results are consistent with the hypothesis that insecticide resistance in the MA strain is due to over-expression of a cytochrome P450.
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Affiliation(s)
- M E Scharf
- Department of Entomology, Purdue University, West Lafayette, IN 47907-1158, USA
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Baker K, Marcus CB, Huffman K, Kruk H, Malfroy B, Doctrow SR. Synthetic combined superoxide dismutase/catalase mimetics are protective as a delayed treatment in a rat stroke model: a key role for reactive oxygen species in ischemic brain injury. J Pharmacol Exp Ther 1998; 284:215-21. [PMID: 9435181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Stroke is a severe and prevalent syndrome for which there is a great need for treatment, including agents to block the cascade of brain injury that occurs in the hours after the onset of ischemia. Reactive oxygen species (ROS) have been implicated in this destructive process, but antioxidant enzymes such as superoxide dismutase (SOD) have been unsatisfactory in experimental stroke models. This study is an evaluation of the effectiveness of salen-manganese complexes, a class of synthetic SOD/catalase mimetics, in a rat focal ischemia model involving middle cerebral artery occlusion. We focus on EUK-134, a newly reported salen-manganese complex demonstrated here to have greater catalase and cytoprotective activities and equivalent SOD activity compared with the previously described prototype EUK-8. The administration of EUK-134 at 3 hr after middle cerebral artery occlusion significantly reduced brain infarct size, with the highest dose apparently preventing further infarct growth. EUK-8 was also protective but substantially less effective. These findings support a key role for ROS in the cascade of brain injury after stroke, even well after the onset of ischemia. The enhanced activity of EUK-134 suggests that, in particular, hydrogen peroxide contributes significantly to this injury. Overall, this study suggests that synthetic SOD/catalase mimetics might serve as novel, multifunctional therapeutic agents for stroke.
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Affiliation(s)
- K Baker
- Eukarion, Inc., Bedford, Massachusetts, USA
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7
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Einolf HJ, Story WT, Marcus CB, Larsen MC, Jefcoate CR, Greenlee WF, Yagi H, Jerina DM, Amin S, Park SS, Gelboin HV, Baird WM. Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis. Chem Res Toxicol 1997; 10:609-17. [PMID: 9168260 DOI: 10.1021/tx960174n] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The environmental contaminant benzo[c]phenanthrene (B[c]Ph) has weak carcinogenic activity in rodent bioassays; however, the fjord region diol epoxides of B[c]Ph, B[c]Ph-3,4-diol 1,2-epoxides (B[c]PhDE), are potent carcinogens. To determine the role of cytochrome P450 isozymes in the activation of B[c]Ph in MCF-7 cells and the low activation of B[c]Ph in mouse skin, cells of the MCF-7 and the human hepatoma HepG2 cell lines were treated with the potent Ah receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prior to exposure to B[c]Ph for 24 h. Mice were treated topically with 1 microg of TCDD or vehicle (control) for 73 h and then with 2 micromol of B[c]Ph for 24 h. In MCF-7 cells, TCDD exposure increased B[c]PhDE-DNA adduct levels more than 3-fold with a 10-fold increase in the (-)-B[c]PhDE-2-dA(t) adduct. Treatment of HepG2 cells with TCDD prior to B[c]Ph application did not increase B[c]PhDE-DNA binding. Total B[c]PhDE-DNA adducts increased 3-fold in TCDD-treated mouse epidermis: the majority of the increase resulted from (+)-B[c]PhDE-1-dA adducts. Analysis of P450 enzymes by Western blotting detected a large increase of P4501B1 but almost no increase in P4501A1 in MCF-7 cells exposed to 10 microM B[c]Ph for 24 or 48 h. In HepG2 cells, there were no detectable levels of P4501A1 or P4501B1 after treatment with 10 microM B[c]Ph for 24 h. In contrast, topical application of 2 micromol of B[c]Ph to mouse skin for 48 or 72 h increased P4501A1, but no P4501B1 was detected. As a measure of P450 activity, the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) was analyzed in microsomes prepared from MCF-7 and HepG2 cells exposed to 0.1% DMSO, 10 microM B[c]Ph, or 10 nM TCDD for 24 or 48 h and from mouse epidermis treated with 1 microg of TCDD, or vehicle control for 72 h, or 2 micromol of B[c]Ph for 48 h. The levels of DMBA metabolites were low or undetectable in microsomes from B[c]Ph-treated MCF-7 and HepG2 cells, but a metabolite pattern consistent with P4501A1 metabolism of DMBA was present in B[c]Ph-exposed mouse epidermal microsomes. TCDD-treated MCF-7 cells, HepG2 cells, and mouse epidermis had DMBA metabolism patterns characteristic of P4501A1 activity. Microsomes from TCDD-treated human cells formed a higher proportion of the proximate carcinogenic metabolite DMBA-3,4-dihydrodiol (16% of total identified metabolites) than TCDD-treated mouse epidermis (2%). In mouse epidermis, the weak ability of B[c]Ph to increase hydrocarbon-metabolizing activity and the increase in mainly P4501A1, leading to formation of the less carcinogenic stereoisomer B[c]PhDE-1, may explain the low carcinogenic activity of B[c]Ph. In a human mammary carcinoma cell line, treatment with B[c]Ph increases mainly P4501B1 and results in formation of a higher proportion of the more carcinogenic B[c]PhDE-2. This indicates that cells in which B[c]Ph treatment increases P4501B1 levels effectively activate B[c]Ph to potent carcinogenic metabolites.
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Affiliation(s)
- H J Einolf
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA
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8
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Taylor MC, McKay JA, Murray GI, Greenlee WF, Marcus CB, Burke MD, Melvin WT. Cytochrome P450 1B1 expression in human malignant tumours. Biochem Soc Trans 1996; 24:328S. [PMID: 8736986 DOI: 10.1042/bst024328s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- M C Taylor
- Department of Pathology, University of Aberdeen
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9
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McKay JA, Murray GI, Ah-See AK, Greenlee WF, Marcus CB, Burke MD, Melvin WT. Differential expression of CYP1A1 and CYP1B1 in human breast cancer. Biochem Soc Trans 1996; 24:327S. [PMID: 8736985 DOI: 10.1042/bst024327s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J A McKay
- Department of Pathology, University of Aberdeen
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10
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Doctrow SR, Huffman K, Marcus CB, Musleh W, Bruce A, Baudry M, Malfroy B. Salen-manganese complexes: combined superoxide dismutase/catalase mimics with broad pharmacological efficacy. Adv Pharmacol 1996; 38:247-69. [PMID: 8895812 DOI: 10.1016/s1054-3589(08)60987-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S R Doctrow
- Eukarion, Inc. Bedford, Massachusetts 01730, USA
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11
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Abstract
The expression of CYP1B1 has been identified in breast cancer using the reverse transcriptase-polymerase chain reaction and immunoblotting. CYP1B1 mRNA was expressed in the majority of breast tumours and immunoblotting of breast tumours identified a single protein band of molecular weight 60 kDa corresponding to the predicted molecular weight of human CYP1B1. This is the first study to identify CYP1B1 expression in a tumour where it may represent a previously unknown pathway for the metabolism of oestradiol and chemotherapeutic drugs.
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Affiliation(s)
- J A McKay
- Department of Pathology, University of Aberdeen, UK
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12
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Polzer RJ, Coffing SL, Marcus CB, Park SS, Gelboin HV, Baird WM. Inhibition of benzo[a]pyrene metabolism by insulin, FITC-insulin and an FITC-insulin-antibody conjugate in the human hepatoma cell line HepG2. Chem Biol Interact 1995; 97:307-18. [PMID: 7671346 DOI: 10.1016/0009-2797(95)03640-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Benzo[a]pyrene (BaP) can be metabolically activated to an ultimate carcinogen, (+)-anti-BaP-7,8-dihydrodiol-9,10-epoxide [(+)-anti-BaPDE] by cells in culture. This activation involves oxidation by specific isoforms of cytochrome P450s such as CYP1A1. The human hepatoma cell line, HepG2, was used to examine the effect of inhibition of CYP1A1 activity by anti CYP1A1 specific antibodies on BaP metabolism. Metabolism of BaP to water-soluble metabolites by HepG2 cells in culture was 50% lower in fluorescein isothiocyanate (FITC)-insulin-CYP1A1-antibody-conjugate-treated cells than in control cells. However, FITC-insulin (lacking anti CYP1A1 conjugates) or insulin alone also decreased BaP metabolism by 50%. This insulin-induced inhibition of BaP metabolism was observed for cultures treated with a concentration range of FITC-insulin from 50-1000 nM. FITC-conjugated gamma-globulin showed no significant binding to HepG2 cells by fluorescence microscopy, however, FITC-insulin-antibody conjugates bound extensively, suggesting that FITC-insulin conjugates still retain the ability to bind insulin receptors. These results demonstrate that free insulin, FITC-insulin or FITC-insulin conjugated to antibodies are effective inhibitors of BaP metabolism in cells in culture.
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Affiliation(s)
- R J Polzer
- Department of Medicinal Chemistry and Pharmacognosy, Purdue University, West Lafayette, IN 47907, USA
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Yoon HL, Marcus CB, Pfeifer RW. Induction of superoxide by 12-O-tetradecanoylphorbol-13-acetate and thapsigargin, a non-phorbol-ester-type tumor promoter, in peritoneal macrophages elicited from SENCAR and B6C3F1 mice: a permissive role for the arachidonic acid cascade in signal transduction. Mol Carcinog 1993; 7:116-25. [PMID: 8384457 DOI: 10.1002/mc.2940070210] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Local production of reactive oxygen intermediates, e.g., superoxide anion, by tumor promoter-stimulated inflammatory macrophages (MPs) may contribute significantly to tumor development in classical models of two-stage chemical-induced carcinogenesis in murine skin. In the studies reported herein, peritoneal MPs elicited from phorbol-ester-sensitive SENCAR mice demonstrated a time- and dose-dependent release of superoxide anion (4-6 nmol/10(6) cells) when stimulated by 200 nM 12-O-tetradecanoylphorbol-13-acetate (TPA) in vitro; MP superoxide response was significantly inhibited (50-70%) by preincubation with 40 microM 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine (H-7), a protein-kinase inhibitor. Alternatively, TPA-stimulated MPs derived from relatively resistant B6C3F1 mice generated negligible superoxide under the same conditions. A similar strain-dependent induction of superoxide was observed when MPs were stimulated with thapsigargin (TG), a tumor promoter previously shown to act independently of protein kinase C (PKC). TG-stimulated SENCAR MPs released a significant amount of superoxide (2-3 nmol/10(6) cells) that was not inhibited by H-7; MPs from B6C3F1 mice demonstrated negligible stimulation by TG. Preincubation of SENCAR MPs with 100 microM dibromoacetophenone, an inhibitor of phospholipase A2, completely suppressed the superoxide induced by TPA and TG stimulation. Like TPA, 50 microM 1-oleoyl-2-acetylglycerol, a diacylglycerol analogue and PKC activator, also induced a significant amount of superoxide from SENCAR MPs only. In parallel with the superoxide findings, TPA and TG stimulated significantly greater [3H]arachidonic acid release from prelabeled SENCAR MPs (a 32% and 48% increase, respectively, over unstimulated controls) relative to MPs from B6C3F1 mice. Two-dimensional gel-electrophoretic analysis indicated that TPA-induced phosphorylation of a 47-kDa protein (a presumed substrate for PKC previously linked to NADPH oxidase activation in guinea pig and human polymorphonuclear leukocytes) occurred in MPs from both SENCAR and B6C3F1 mice. Therefore, arachidonic acid production may be a common biochemical pathway by which phorbol-ester--and non-phorbol-ester--type tumor promoters activate MPs in SENCAR mice; such a response may be "permissive" for additive (or synergistic) interactions with PKC-driven signal pathways.
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Affiliation(s)
- H L Yoon
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana
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Day BJ, DeNicola DB, Marcus CB, Carlson GP. Effect of p-xylene inhalation on the bioactivation of bromobenzene in rat lung and liver. Fundam Appl Toxicol 1992; 19:50-6. [PMID: 1397801 DOI: 10.1016/0272-0590(92)90027-f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is unclear whether the pneumotoxicity observed with bromobenzene (BB) in phenobarbital-induced rats is related to BB bioactivation in lung, liver or both. To help differentiate pulmonary from hepatic bioactivation, BB was administered alone and in combination with p-xylene, which inhibits pulmonary but induces hepatic cytochromes P450. Exposure to p-xylene alone (3400 ppm for 4 hr) produced no changes in bronchoalveolar lavage fluid (BALF) measurements (gamma-glutamyl transpeptidase, lactate dehydrogenase, protein, white blood cell count) or serum sorbitol dehydrogenase. p-Xylene increased hepatic microsomal benzyloxy- (BROD), pentoxy- (PROD), and ethoxy- (EROD) resorfuin O-dealkylase activities but decreased pulmonary microsomal BROD and PROD. Immunoblot analysis revealed an induction of hepatic but not pulmonary microsomal P450IIB apoprotein. When rats were exposed to p-xylene (2800 ppm) or room air for 4 hr, treated 12 hr later with BB (0.5 ml/kg, ip) or corn oil, and killed after 12 hr, p-xylene increased hepatic P450IIB (27-fold) concomittant with a similar increase in BROD activity. p-Xylene also increased hepatic P450IA apoprotein (3.4-fold) with a complimentary increase in EROD activity. p-Xylene potentiated BB-induced hepatotoxicity. In pulmonary microsomes p-xylene and BB each produced similar decreases in both EROD and BROD activities. The combination of p-xylene and BB had an additive effect on pulmonary P450IA1 reduction. BALF analysis and histopathology revealed no pneumotoxicity with any treatment. p-Xylene potentiation of BB-induced hepatotoxicity without pneumotoxicity suggests that the liver does not produce metabolites of BB which are directly involved in pulmonary damage.
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Affiliation(s)
- B J Day
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907
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15
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Chae YH, Ho DK, Cassady JM, Cook VM, Marcus CB, Baird WM. Effects of synthetic and naturally occurring flavonoids on metabolic activation of benzo[a]pyrene in hamster embryo cell cultures. Chem Biol Interact 1992; 82:181-93. [PMID: 1568269 DOI: 10.1016/0009-2797(92)90109-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Biochanin A, an isoflavone, has previously been shown to inhibit the metabolic activation of the carcinogen benzo[a]pyrene (B[a]P) to metabolites that bind to DNA in hamster embryo cells and are mutagenic in Chinese hamster V79 cells. To determine the structural features required for this activity and to attempt to find more effective inhibitors, a series of synthetic and naturally occurring flavonids were tested for their ability to modulate B[a]P metabolism in hamster embryo cell cultures. The observed structure-activity relationships indicate that the structural features of flavonoids important for effective inhibition of B[a]P metabolism in hamster embryo cells are the presence of two hydroxyl, two methoxyl, or methyl and hydroxyl substituents at the 5- and 7-positions and a 2,3-double bond. Flavones are slightly better inhibitors of B[a]P metabolism than the corresponding isoflavones. A substituent at the 4'-position is not essential for inhibition of B bdP metabolism. The presence of a hydroxyl group at position 3 slightly enhances activity. Apigenin, acacetin and kaempferide are effective inhibitors of B[a]P-induced mutagenesis in a hamster embryo cell-mediated V79 cell mutation assay. However, apigenin is cytotoxic at the inhibitory dose, whereas acacetin and kaempferide are not. These results suggest that acacetin and kaempferide are promising candidates for in vivo testing as potential chemopreventive agents.
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Affiliation(s)
- Y H Chae
- Department of Medicinal Chemistry and Pharmacognosy, School of Pharmacy, Purdue University, West Lafayette, IN 47907
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Chae YH, Marcus CB, Ho DK, Cassady JM, Baird WM. Effects of synthetic and naturally occurring flavonoids on benzo[a]pyrene metabolism by hepatic microsomes prepared from rats treated with cytochrome P-450 inducers. Cancer Lett 1991; 60:15-24. [PMID: 1913623 DOI: 10.1016/0304-3835(91)90044-i] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Activity-directed fractionation of Trifolium pratense resulted in isolation of the isoflavone biochanin A, a potent inhibitor of metabolic activation of the carcinogen benzo[a]pyrene (B[a]P) in cells in culture. To determine the structural features required for maximal inhibition of cytochrome P-450 mediated metabolism of B[a]P, the inhibitory potencies of 23 flavonoids on metabolism of B[a]P to water-soluble derivatives were examined in liver S-9 homogenate from rats induced with Aroclor 1254. Flavones were much more efficient inhibitors than their corresponding isoflavone or flavanone analogs. Most flavonols were as effective inhibitors as their flavone analogs with the exception of kaempferide. Flavones with two hydroxyl or two methoxyl groups at positions 5 and 7 were the most active. Although all eight flavonoids tested effectively inhibited B[a]P metabolism by beta-naphthoflavone-induced microsomes, none were very effective inhibitors of B[a]P metabolism by phenobarbitol-induced microsomes, and only three were effective inhibitors of B[a]P metabolism by microsomes from non-induced rats. These results indicate that flavones or flavonols that contain free 5- and 7-hydroxyls are potent inhibitors of P-450 induced by beta-naphthoflavone (P-450IA1 and/or P-450IA2) and may potentially be useful as chemopreventive agents against hydrocarbon-induced carcinogenesis.
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Affiliation(s)
- Y H Chae
- Department of Medicinal Chemistry and Pharmacognosy, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, IN 47907
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Updyke LW, Yoon HL, Kiorpes AL, Robinson JP, Pfeifer RW, Marcus CB. 3-Methylindole-induced splenotoxicity: biochemical mechanisms of cytotoxicity. Toxicol Appl Pharmacol 1991; 109:375-90. [PMID: 1853340 DOI: 10.1016/0041-008x(91)90001-u] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
3-Methylindole (3-MI) is a pneumotoxic metabolite of L-tryptophan that can form in the digestive tracts of humans and ruminants as a result of microbial protein metabolism. Alternatively, human lungs can be directly exposed to 3-MI formed during protein pyrolysis and inhalation of tobacco smoke. 3-MI has been shown to cause acute lung injury in both ruminants and rodents. The present studies demonstrate that the spleen is also a target for 3-MI-induced toxicity. A dose-dependent decrease in splenic weight (24-75%) and nucleated splenic cell number (22-68%) was observed 24 hr after intraperitoneal injection of 3-MI (50-300 mg/kg) to intact and adrenalectomized rats. These findings were associated with significant alterations in splenic histopathology. Mice appeared less affected by 3-MI than rats as no splenotoxicity was observed at doses less than 200 mg/kg. Other mono- and dimethyl-substituted indoles did not decrease mouse spleen cell numbers when administered in vivo. Phenobarbital pretreatment in vivo protected against 3-MI-induced splenotoxicity, suggesting a role for cytochrome P450-mediated metabolism of 3-MI in the splenotoxicity of this compound. Exposure of rat or mouse splenic cells to 3-MI (1 mM) in vitro resulted in toxic changes over 24 hr. However, equimolar concentrations of the structurally related mono- and dimethylindoles were also toxic in vitro, and preincubation with a variety of inhibitors of cytochrome P450 or prostaglandin synthase in vitro failed to protect against 3-MI-mediated toxicity to splenic cells in culture. These results suggest mechanisms of 3-MI splenotoxicity also exist that do not require bioactivation, and indicate a possible role for alkylindoles in suppression of immune function.
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Affiliation(s)
- L W Updyke
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907
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Updyke LW, Yoon HL, Robinson JP, Kiorpes AL, Marcus CB, Pfeifer RW. 3-Methylindole-induced splenotoxicity: functional analysis of immune parameters and lymphocyte phenotyping by flow cytometry. Toxicol Appl Pharmacol 1991; 109:391-8. [PMID: 1853341 DOI: 10.1016/0041-008x(91)90002-v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In this laboratory, 3-methylindole (3-MI), a pneumotoxic metabolite of L-tryptophan that forms in the digestive tract of humans and ruminants, has been demonstrated to be toxic to rat and mouse splenic cells both in vitro and in vivo. The present studies examine whether the reduction in nucleated splenic cells is associated with alterations in: (1) immune functioning (e.g., B and T cell mitogenic responses to lectins), (2) natural resistance (e.g., natural killer (NK) activity and cytokine release from macrophages (MPs)), or (3) the relative percentages of B and T cells in the remaining cells as determined by flow cytometric phenotyping. A dose-dependent decrease in splenic weight (24-46%) and nucleated cell numbers (54-73%) was observed 24 hr after intraperitoneal (ip) administration of 100-300 mg/kg 3-MI to B6C3F1 mice. At a dose of 300 mg/kg, the blastogenic response of splenic lymphocytes to 1 microgram/ml phytohemagglutinin, a T cell mitogen, was reduced 37 and 64%, and NK activity was reduced 20 and 60%, in rats and mice, respectively. Following exposure to 400 mg/kg 3-MI, interleukin-1 and tumor necrosis factor production by lipopolysaccharide-stimulated rat splenic MPs was decreased 58 and 38%, respectively. Despite the reduction in total nucleated cell number in 3-MI-treated mice, the percentages of splenic B and T cells remained the same. These findings indicate that, in addition to its toxicity to splenic cells, 3-MI can significantly impair the functioning of the remaining viable cells. The potential importance of these functional changes for alterations in host resistance in rodents exposed to 3-MI or other alkylindoles is unknown.
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Affiliation(s)
- L W Updyke
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907
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Marcus CB, Wilson NM, Keith IM, Jefcoate CR, Omiecinski CJ. Selective expression of cytochrome P450 isozymes by 4-n-alkyl-methylenedioxybenzenes in rat lung cells. Arch Biochem Biophys 1990; 277:17-25. [PMID: 2306118 DOI: 10.1016/0003-9861(90)90544-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Rat lung preparations were analyzed for cytochrome P450 expression as a function of pretreatment with 1 mmol/kg/day of various substituted n-alkyl-methylenedioxybenzenes (MDBs). Lung P450s were quantitated by Western blotting and visualized by immunocytochemical techniques using polyclonal antibodies directed against P450IA1/IA2 and P450IIB1/IIB2. Results demonstrated that n-hexyl and n-octyl-MDB (but not n-butyl-MDB) increased P450IA1 in lung microsomes (50 pmol/mg microsomal protein) compared to untreated controls and n-butyl-MDB-treated animals (6 pmol/mg). However, treatment with all of these MDBs concomitantly decreased P450IIB1 in rat lung microsomes, from 40 pmol/mg in untreated control lungs to below the detection limit of this method (less than 2 pmol/mg). In vitro metabolism assays with rat lung microsomes, utilizing 7,12-dimethylbenz[a]anthracene as substrate, confirmed the increase in P450IA1 by selected MDBs and the concomitant decrease of catalytically active P450IIB1. Immunocytochemistry of rat lungs with these same IgGs indicated selective cellular responses. n-Hexyl-MDB (but not n-butyl-MDB) increased P450IA1-like immunoreactivity, but the increase was specifically localized to Clara cells. Immunocytochemical results further showed that P450IIB1-like immunoreactivity disappeared entirely from alveolar type II cells, yet appeared unchanged in Clara cells relative to untreated controls. Increases in P450IA1 due to treatment with n-hexyl-MDB were associated with increases in P450IA1 mRNA as indicated by Northern blot experiments. In contrast, the decreased levels of P450IIB1, consequent to treatment with n-alkyl-MDBs, were not associated with altered levels of pulmonary P450IIB1 mRNA as determined by Northern blotting and solution hybridization assays. These results imply that n-alkyl-MDBs regulate pulmonary cytochromes P450 by both transcriptional and post-transcriptional mechanisms.
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Affiliation(s)
- C B Marcus
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907
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Marcus CB, Wilson NM, Jefcoate CR, Wilkinson CF, Omiecinski CJ. Selective induction of cytochrome P450 isozymes in rat liver by 4-n-alkyl-methylenedioxybenzenes. Arch Biochem Biophys 1990; 277:8-16. [PMID: 2306127 DOI: 10.1016/0003-9861(90)90543-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To examine the structural requirements of cytochrome P450 induction by 4-n-alkyl-substituted methylenedioxybenzenes (MDBs), rats were treated in vivo with a series of MDBs that differed in alkyl carbon side-chain length (0, 1, 2, 3, 4, 5, 6, or 8). Expression patterns of specific P450 isozymes were evaluated with Western and Northern blotting, enzymatic assays, and solution hybridization assays. As determined by carbon monoxide difference spectroscopy, maximal hepatic induction of total P450 content occurred when rats were treated with MDB derivatives with alkyl chain lengths of five or six carbons. However, maximum induction of the specific P450s--P450IA1, P450IIB1, and P450IIB2--occurred with n-hexyl-MDB. In contrast to effects observed with phenobarbital, treatment with MDBs resulted in higher levels of P450IIB2 than of P450IIB1 in rat hepatic microsomes. Western blot quantitation of MDB-induced hepatic P450IIB1 and P450IIB2 apoenzymes did not correlate to measured levels of the corresponding P450 mRNAs. In fact, P450IIB1 and P450IIB2 apoenzyme levels were consistently lower than expected based on Northern blot and solution hybridization measures of the respective mRNAs. These data suggest that the n-alkyl-MDBs effect increases in levels of hepatic P450 in a complex manner, producing accumulation of P450 mRNAs concomitant with alterations in processes regulating steady-state levels of P450 apoenzyme.
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Affiliation(s)
- C B Marcus
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907
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Turner CR, Marcus CB, Jefcoate CR. Selectivity in the binding of hydroxylated benzo[a]pyrene derivatives to purified cytochrome P-450c. Biochemistry 1985; 24:5124-30. [PMID: 4074683 DOI: 10.1021/bi00340a025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The interaction of rat liver microsomal cytochrome P-450c with potential benzo[a]pyrene (BP) metabolites has been compared with the binding of BP by optical and fluorescence spectroscopy. Fluorescence quenching of the phenolic derivatives of BP derives from 1:1 complex formation with P-450c, is a function of the position of the hydroxyl substituent, and correlates with the concomitant increase in high-spin cytochrome observed in parallel optical titrations. The proportion of high-spin cytochrome seen when P-450c was reconstituted in dilauroylphosphatidylcholine vesicles (60 micrograms/mL) ranged from about 7% for the 3- and 7-phenols to 75% for 11- and 12-phenols. BP and all 12 methyl-BP derivatives have comparable high affinities for P-450c (50-70% high spin). Kd determinations with purified P-450c indicated very strong binding of BP phenols that induce high-spin complexes (4-, 5-, 9-, 10-, 11-, and 12-phenols; Kd = 3-25 nM). Inhibition of n-octylamine binding by the 3- and 7-phenols indicated weak interactions (Kd = 80-90 nM), even though low-spin complexes were formed. Inhibition of BP metabolism catalyzed by P-450c with BP phenols correlated with their respective dissociation constants. These results suggest that phenolic substitution at certain positions on BP (1, 2, 3, 7, or 8) interferes with binding to the active site while substitutions at the other positions either enhance or have no effect on binding. BP dihydrodiols [including the (+)- and (-)-BP 7,8-dihydrodiols] were relatively ineffective in forming high-spin complexes (approximately 20%), and fluorescence quenching of dihydrodiols by P-450c also saturated at low levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
Benzo[a]pyrene (BP) fluorescence-emission intensities in phospholipid micelles are quantitatively described over a broad range of lipid and BP concentrations by excitation that is linearly dependent upon BP concentration and an offsetting excimer quenching that is dependent upon the square of the BP concentration. The fluorescence of BP is quenched by the presence of cytochrome P-450c in proportion to the concentration of the cytochrome in the micelles and in accord with stoichiometric complex formation. Parallel optical titrations indicate a change in spin state of P-450c to a predominantly high-spin state that correlates directly with the percentage fluorescence quenching of complexed BP. Neither change occurs with five other purified forms of rat liver P-450 that have low activity in BP metabolism. N-Octylamine, a ligand that binds to the heme of P-450, competitively inhibits both the spin-state changes and the fluorescence quenching in equal proportion. The Kd for the interaction of BP with P-450c is exceptionally low (10 nM) relative to the Km for monooxygenation (ca. 1 microM). Decreasing the concentration of either dilauroylphosphatidylcholine or dioleoylphosphatidylcholine concomitantly increases the high-spin state (from 30% to 80%) of fully complexed P-450c and the fluorescence quenching (50-100%) of the complexed BP (half-maximal at 80 micrograms of lipid/mL). It is concluded that spin state and fluorescence quenching both reflect the same changes in the interaction of the BP with the P-450 heme.(ABSTRACT TRUNCATED AT 250 WORDS)
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Marcus CB, Murray M, Wilkinson CF. Spectral and inhibitory interactions of methylenedioxyphenyl and related compounds with purified isozymes of cytochrome P-450. Xenobiotica 1985; 15:351-62. [PMID: 4024670 DOI: 10.3109/00498258509045370] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Spectral and inhibitory interactions of two methylenedioxyphenyl (MDP) compounds (dihydrosafrole (DHS) and 4,5-dichloro-1,2-methylenedioxybenzene (DCMB] and 4-n-butyl dioxolane (BD) were studied in vitro in reconstituted systems incorporating cytochromes P-450b and P-450c, purified respectively from hepatic microsomes of phenobarbital (PB)- and beta-naphthoflavone (beta NF)-treated rats. In NADPH-fortified reconstituted systems containing P-450b, DHS yielded a stable type III spectral complex with peaks at 428 and 458 nm; a complex with a single 456 nm peak was formed in systems containing cytochrome P-450c. DCMB formed unstable 456-458 nm spectral complexes with both isozymes, and BD generated an unstable complex with a single Soret peak near 428 nm with cytochrome P-450b; no spectral interaction occurred between BD and cytochrome P-450c. Carbon monoxide was formed in incubations of DCMB with both isozymes but was not observed with either DHS or BD. Marked selectivity was observed in the ability of the test compounds to inhibit selected mono-oxygenase reactions in the reconstituted systems. Thus, while DHS was an effective inhibitor of cytochrome P-450b-mediated ethoxycoumarin O-deethylase (ECD), it failed to inhibit aldrin epoxidase (AE) in the same system; DCMB and BD inhibited both of these reactions. In reconstituted systems incorporating cytochrome P-450c, DHS and DCMB, but not BD, were effective inhibitors of ethoxyresorufin O-deethylase (ERD) activity but none of the compounds showed any inhibitory activity towards aryl hydrocarbon (benzo[alpha]pyrene)hydrolase (AHH) activity. The results indicate that metabolite complex formation with cytochrome P-450 is not the sole criterion for inhibition of mono-oxygenase activity by MDP and related compounds, and that in some cases type I competitive interactions at the substrate binding sites may be the primary contributing factor.
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