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Glaser J, Chakraborty D, Kroy K, Lauter I, Degawa M, Kirchgessner N, Hoffmann B, Merkel R, Giesen M. Tube width fluctuations in F-actin solutions. Phys Rev Lett 2010; 105:037801. [PMID: 20867808 DOI: 10.1103/physrevlett.105.037801] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Indexed: 05/29/2023]
Abstract
We determine the statistics of the local tube width in F-actin solutions, beyond the usually reported mean value. Our experimental observations are explained by a segment fluid theory based on the binary collision approximation. In this systematic generalization of the standard mean-field approach, effective polymer segments interact via a potential representing the topological constraints. The analytically predicted universal tube width distribution with a stretched tail is in good agreement with the data.
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Affiliation(s)
- J Glaser
- Institut für Theoretische Physik, Universität Leipzig, PF 100920, 04009 Leipzig, Germany.
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2
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Abstract
1. Nicardipine (Nic) or nifedipine (Nif) was given to male and female C57BL/6J mice by a single gavage at doses of 100, 200 and 400 micromolkg(-1), and changes in the levels of mRNA and apoprotein of hepatic cytochrome P450 (P450) enzymes, including Cyp2b9, Cyp2b10, Cyp3a11 and Cyp3a41, were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting, respectively. Furthermore, hepatic microsomal activities for pentoxyresorufin O-dealkylation (PROD) and nifedipine oxidation, which are mainly mediated by Cyp2b and Cyp3a subfamily enzymes, respectively, were measured. 2. Results from RT-PCR analysis revealed that Nic, but not Nif, showed a capacity for activating the Cyp3a11 gene in either sex of mice and that both chemicals could induce a male-selective activation of Cyp2b10 gene, although they had no capacity for activating the Cyp2b9 and Cyp3a41 genes in either sex. 3. Increased levels of the mRNAs of Cyp2b10 and Cyp3a11 were closely correlated with those of apoprotein and activity of the corresponding P450 subfamily enzymes. 4. The study demonstrated for the first time that Nic, but not Nif, showed the ability to induce Cyp3a11 in both sexes of mice, although both Nif and Nic led to a male-selective induction of Cyp2b10, and that Nic and Nif had no ability to induce Cyp2b9 and Cyp3a41 in either sex.
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Affiliation(s)
- Y Konno
- Department of Molecular Toxicology and COE Program in the 21st Century, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
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3
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Haraguchi K, Kato Y, Koga N, Degawa M. Species differences in the tissue distribution of catechol and methylsulphonyl metabolites of 2,4,5,2',5'-penta- and 2,3,4,2',3',6'-hexachlorobiphenyls in rats, mice, hamsters and guinea pigs. Xenobiotica 2008; 35:85-96. [PMID: 15788370 DOI: 10.1080/00498250400026456] [Citation(s) in RCA: 8] [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: 10/25/2022]
Abstract
Polychlorinated biphenyls (PCBs) are metabolized to phenolic or methylsulphonyl PCBs (MeSO(2)-CBs) in animal species. The study determined the species differences in the tissue distribution of persistent PCB metabolites in rats, mice, hamsters and guinea pigs 4 days after exposure to 2,4,5,2('),5(')-pentachlorobiphenyl (CB101) or 2,3,4,2('),3('),6(')-hexachlorobiphenyl (CB132). For CB101 metabolism, the hydroxylation in rats, mice and hamsters occurred primarily at the 3(')-position in the 2('),5(')-dichlorinated phenyl ring, whereas the hydroxylation in guinea pigs occurred preferentially at the 3-position. Metabolite profiles in tissues of hamsters were dominated by 3('),4(')-catechol-CB101, whereas metabolite profiles in rats and mice were dominated by 3(')- or 4(')-MeSO(2)-CBs. For CB132 metabolism, rats and mice produced 4(')- and 5(')-MeSO(2)-CBs at similar concentration ratios, whereas guinea pigs produced MeSO(2)-CBs at higher levels and selectively retained 5(')-MeSO(2)-CB in liver. In contrast, hamsters preferentially produced 4('),5(')-catechol-CB132 that was retained in serum. Consequently, hamsters produced catechols, whereas guinea pigs produced meta-substituted MeSO(2)-CBs, preferentially from CB132. These findings indicate that PCBs with 2,3,6-chlorine substitution are preferred substrates for the formation of catechols or MeSO(2)-CBs and the differences in metabolite profiles are related to species-dependent metabolic capacities.
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Affiliation(s)
- K Haraguchi
- Daiichi College of Pharmaceutical Sciences, Fukuoka, Japan.
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Bondarchuk O, Cullen WG, Degawa M, Williams ED, Bole T, Rous PJ. Biased surface fluctuations due to current stress. Phys Rev Lett 2007; 99:206801. [PMID: 18233173 DOI: 10.1103/physrevlett.99.206801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2007] [Indexed: 05/25/2023]
Abstract
Direct correlation between temporal structural fluctuations and electron wind force is demonstrated, for the first time, by STM imaging and analysis of atomically resolved motion on a thin film surface under large applied current (10(5) A/cm2). The magnitude of the momentum transfer between current carriers and the geometrically constrained atoms in the fluctuating structure is at least 5x to 15x (+/-1sigma range) larger than for freely diffusing adatoms. Corresponding changes in surface resistivity will contribute significant fluctuation signature to nanoscale electronic properties.
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Affiliation(s)
- O Bondarchuk
- Department of Physics, University of Maryland at College Park, College Park, Maryland 20742-4111, USA
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5
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Degawa M, Stasevich TJ, Cullen WG, Pimpinelli A, Einstein TL, Williams ED. Distinctive fluctuations in a confined geometry. Phys Rev Lett 2006; 97:080601. [PMID: 17026286 DOI: 10.1103/physrevlett.97.080601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Revised: 05/30/2006] [Indexed: 05/12/2023]
Abstract
Spurred by recent theoretical predictions [Phys. Rev. E 69, 035102(R) (2004)10.1103/PhysRevE.69.035102; Surf. Sci. Lett. 598, L355 (2005)10.1016/j.susc.2005.09.023], we find experimentally using STM line scans that the fluctuations of the step bounding a facet exhibit scaling properties distinct from those of isolated steps or steps on vicinal surfaces. The correlation functions go as t0.15 +/- 0.03 decidedly different from the t0.26 +/- 0.02 behavior for fluctuations of isolated steps. From the exponents, we categorize the universality, confirming the prediction that the nonlinear term of the Kardar-Parisi-Zhang equation, long known to play a central role in nonequilibrium phenomena, can also arise from the curvature or potential-asymmetry contribution to the step free energy.
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Affiliation(s)
- M Degawa
- Department of Physics, University of Maryland, College Park, Maryland 20742-4111 USA.
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Konno Y, Nemoto K, Degawa M. Induction of hepatic cytochrome P450s responsible for the metabolism of xenobiotics by nicardipine and other calcium channel antagonists in the male rat. Xenobiotica 2003; 33:119-29. [PMID: 12623755 DOI: 10.1080/0049825021000023987] [Citation(s) in RCA: 10] [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: 10/26/2022]
Abstract
1. The effects of nicardipine and three other calcium channel antagonists, nifedipine, diltiazem and verapamil, on hepatic gene expression of cytochrome P450s (P450), CYP1A1, CYP1A2, CYP2B1, CYP2B2, CYP3A1 and CYP3A2 in male rats were examined by an RT-PCR method. 2. Treatment of rats with nicardipine resulted in a significant increase in hepatic expression of all the P450 genes examined. Other calcium channel antagonists, nifedipine, diltiazem and verapamil, also enhanced the gene expression of CYP2B1, CYP2B2, CYP3A1 and CYP3A2, although these showed no capacity for activating CYP1A1 and CYP1A2 genes. 3. We have demonstrated for the first time that nicardipine activated not only the genes of CYP2B1, CYP2B2, CYP3A1 and CYP3A2, but also those of CYP1A1 and CYP1A2 in the rat liver and have further suggested that calcium channel antagonists may show a common capacity for activating the genes of CYP2B1, CYP2B2, CYP3A1 and CYP3A2. Furthermore, this increased expression of P450 genes was demonstrated to contribute to increase in the protein level of the corresponding P450s.
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Affiliation(s)
- Y Konno
- Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
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7
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Sano M, Tabata M, Suzuki M, Degawa M, Miyase T, Maeda-Yamamoto M. Simultaneous determination of twelve tea catechins by high-performance liquid chromatography with electrochemical detection. Analyst 2001; 126:816-20. [PMID: 11445943 DOI: 10.1039/b102541b] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [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: 11/21/2022]
Abstract
A high-performance liquid chromatographic method with electrochemical detection was developed for the determination of twelve tea catechins including four major catechins: epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG); four of their epimers at the C-2 position, C, GC, CG and GCG; and four methylated catechin derivatives, epigallocatechin-3-O-(3-O-methyl)gallate, gallocatechin-3-O-(3-O-methyl)gallate, epigallocatechin-3-O-(4-O-methyl)gallate and epicatechin-3-O-(3-O-methyl)gallate. These catechins were separated on an ODS C18 reversed-phase column by isocratic elution with 0.1 M NaH2PO4 buffer (pH 2.5)-acetonitrile (87:13) containing 0.1 mM EDTA.2Na. The detection limits (S/N = 3) of these catechins were approximately 10-40 pmol ml-1 at an applied voltage of 600 mV. Extracting these catechins from tea leaf powder with H2O-acetonitrile (1:1) at 30 degrees C for 40 min inhibited the epimerization at C-2 significantly from these epicatechins compared to extraction with hot water at 90 degrees C. This analytical method is sensitive to and appropriate for the simultaneous determination of various biologically active catechins in green tea.
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Affiliation(s)
- M Sano
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
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Abe I, Umehara K, Morita R, Nemoto K, Degawa M, Noguchi H. Green tea polyphenols as potent enhancers of glucocorticoid-induced mouse mammary tumor virus gene expression. Biochem Biophys Res Commun 2001; 281:122-5. [PMID: 11178969 DOI: 10.1006/bbrc.2001.4325] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [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: 11/22/2022]
Abstract
The effect of natural and synthetic galloyl esters on glucocorticoid-induced gene expression was evaluated by using rat fibroblast 3Y1 cells stably transfected with a luciferase reporter gene under the transcriptional regulation of the mouse mammary tumor virus promoter. The glucocorticoid-induced gene transcription was strongly suppressed by synthetic alkyl esters; n-dodecyl gallate showed the most potent inhibition (66% inhibition at 10 microM), which was far more potent than that of crude tannic acid. n-Octyl and n-cetyl gallate also showed good inhibition, while gallic acid itself was not so active, suggesting that the presence of hydrophobic side chain is important for the suppressive effect. On the other hand, surprisingly, green tea gallocatechins, (-)-epigallocatechin-3-O-gallate and theasinensin A, potently enhanced the promoter activity (182 and 247% activity at 1 microM, respectively). The regulation of the level of the glucocorticoid-induced gene expression by the antioxidative gallates is of great interest from a therapeutic point of view.
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Affiliation(s)
- I Abe
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka, 422-8526, Japan.
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9
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Abstract
Formation of adducts has been considered to be a major causal factor of DNA damage by carcinogenic aminoazo dyes. We investigated whether a metabolite of hepatocarcinogenic 4-dimethylaminoazobenzene (DAB) can cause oxidative DNA damage or not, using (32)P-5'-end-labeled DNA fragments. The DAB metabolite N-hydroxy-4-aminoazobenzene (N-OH-AAB) was found to cause Cu(II)-mediated DNA damage, including 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation. When an endogenous reductant, beta-nicotinamide adenine dinucleotide (NADH) was added, the DNA damage was greatly enhanced. Very low concentrations of N-OH-AAB could induce DNA damage via redox reactions. Catalase and a Cu(I)-specific chelator inhibited the DNA damage, suggesting the involvement of H2O2 and Cu(I). A typical.OH scavenger did not inhibit the DNA damage. The main reactive species are probably DNA-copper-hydroperoxo complexes. We conclude that oxidative DNA damage may play an important role in the carcinogenic processes of DAB, in addition to DNA adduct formation.
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Affiliation(s)
- S Ohnishi
- Department of Hygiene, Mie University School of Medicine, Tsu, Mie 514-8507, Japan
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Nemoto K, Miyata S, Nemoto F, Yasumoto T, Murai U, Kageyama H, Degawa M. Gene expression of neurotrophins and their receptors in lead nitrate-induced rat liver hyperplasia. Biochem Biophys Res Commun 2000; 275:472-6. [PMID: 10964689 DOI: 10.1006/bbrc.2000.3340] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [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: 11/22/2022]
Abstract
Neurotrophins including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) are known to play important roles in the survival, proliferation, differentiation, and/or maintenance of function in several tissues including neuronal tissues. The role of neurotrophins in liver tissue, however, has not yet been clarified. In the present study, we assessed the temporal change in gene expression of neurotrophins, NGF, BDNF, and NT-3, and their receptors, low affinity neurotrophin receptor (p75NTR) and Trks A, B, and C, by RT-PCR technique in the liver of rats treated with lead nitrate (LN; 0.1 mmol/kg body weight), an inducer of liver hyperplasia. The mRNAs for NGF, BDNF with exon 4, NT-3, p75NTR, and all Trk members were detected in the LN-untreated liver. LN treatment resulted in increases in the levels of NGF, BDNF with exon 4, NT-3, p75NTR, and TrkA mRNAs and further led to expression of BDNF mRNA with exon 3. The increase in gene expression of neurotrophins and their receptors was closely correlated with those in liver weight. In this report, we propose for the first time that neurotrophins may play crucial roles in LN-induced liver hyperplasia.
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Affiliation(s)
- K Nemoto
- Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka, 422-8526, Japan.
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Abstract
A 45-year-old woman was transferred from a local hospital to our hospital because of shock-like manifestations in addition to septic polyarthritis and necrotizing cellulitis of the left leg. Since Streptococcus pyogenes was isolated from the blood culture examined one day before admission, the diagnosis of streptococcal toxic shock-like syndrome (TSLS) was made. Antibiotic treatment together with supportive care started at the time of admission, resulting in clinical improvement, although poststreptococcal acute glomerulonephritis occurred during the period. TSLS is a life-threatening disease, but early recognition of the disease and prompt initiation of appropriate treatment may lead to successful outcome.
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Affiliation(s)
- A Saeki
- First Department of Internal Medicine, Nagasaki University School of Medicine
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12
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Tsuda H, Sekine K, Uehara N, Takasuka N, Moore MA, Konno Y, Nakashita K, Degawa M. Heterocyclic amine mixture carcinogenesis and its enhancement by caffeine in F344 rats. Cancer Lett 1999; 143:229-34. [PMID: 10503909 DOI: 10.1016/s0304-3835(99)00130-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [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: 11/18/2022]
Abstract
In order to elucidate whether mixed exposure to environmental carcinogens and caffeine increases the risk of cancer induction, we investigated the relationship between preneoplastic lesion development in the liver and colon and drug metabolizing enzyme induction and DNA adduct formation, in rats treated with a mixture of heterocyclic amines (HCAs) and caffeine. In Experiment 1, male F344 rats were administered 3 different HCAs, the food carcinogens, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), alone or in combinations of 2 or 3 at 50 ppm in the diet for 16 weeks. The numbers of hepatic glutathione-S-transferase P form positive (GST-P+) foci and colonic aberrant crypt foci (ACF) were greater in the IQ + MeIQx group than expected from simple summation and increased levels of HCA-DNA adducts were noted. However, no summation was obtained when combined with PhIP, which rather caused inhibition. In Experiment 2, the effects of concurrent caffeine administration on the PhIP carcinogenicity were assessed. Caffeine at 1000 and 500 ppm in the drinking water for 2 weeks significantly increased levels of CYP1A2. Ten weeks concurrent administration of caffeine (1000 ppm) and PhIP (400 ppm) resulted in significant increase of colon ACFs and CYP1A2 expression. Thus, concurrent administration of IQ and MeIQx caused elevation of their carcinogenicity but other mixtures with PhIP did not enhance carcinogenicity. However, a non-carcinogen, caffeine, enhanced PhIP colon carcinogenesis, possibly due to induction of CYP1A2.
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Affiliation(s)
- H Tsuda
- Experimental Pathology and Chemotherapy Division, National Cancer Center Research Institute, Tokyo, Japan
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13
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Nemoto K, Sekimoto M, Fukamachi K, Nemoto F, Miyata S, Nakamura Y, Hamada M, Senba E, Ueyama T, Degawa M. A possible mechanism of TPA-mediated downregulation of neurotrophin-3 gene expression in rat cultured vascular smooth muscle cells. Brain Res Mol Brain Res 1999; 68:186-9. [PMID: 10320796 DOI: 10.1016/s0169-328x(99)00088-1] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We have previously reported that in cultured rat vascular smooth muscle cells (VSMCs), neurotrophin-3 (NT-3) gene expression was suppressed by TPA (12-O-tetradecanoyl phorbol-13-acetate), which induces an AP-1 transcription factor. In the present study, to clarify the mechanism for TPA-mediated downregulation of NT-3 gene expression, effects of cycloheximide and dexamethasone (Dex) on the TPA-mediated downregulation were examined in VSMCs. Pretreatment with cycloheximide, an inhibitor of protein synthesis, or simultaneous treatment with Dex, an inhibitor of AP-1, suppressed the TPA-mediated downregulation of NT-3 gene expression. Furthermore, co-transfection of c-fos and c-jun expression vectors into VSMCs resulted in decrease in the NT-3 gene expression. The present findings suggest that TPA-induced AP-1 de novo synthesis causes the downregulation of NT-3 gene expression in VSMCs.
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Affiliation(s)
- K Nemoto
- Laboratory of Health Science, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka, 422-8526, Japan.
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Kusuda A, Migita K, Tsuboi M, Degawa M, Matsuoka N, Tominaga M, Kawakami A, Kawabe Y, Taguchi T, Eguchi K. Successful treatment of adult-onset Henoch-Schönlein purpura nephritis with high-dose immunoglobulins. Intern Med 1999; 38:376-9. [PMID: 10361914 DOI: 10.2169/internalmedicine.38.376] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 26-year-old woman was admitted for the evaluation of edema and massive proteinuria. She had a history of purpura of the lower extremities, abdominal pain and melena. Laboratory investigations showed hypoalbuminemia, hypercholesterolemia and proteinuria of over 10 g/day. Renal biopsy showed moderate proliferative glomerulonephritis with mesangial immunoglobulin A (IgA) deposition. She was diagnosed as having Henoch-Schonlein purpura nephritis. Oral prednisolone, dipyridamole and intravenous heparin treatment were not effective. Steroid pulse therapy induced a partial improvement of proteinuria to 2-3 g/day. High-dose intravenous immunoglobulin (i.v.-IG) treatment was introduced and a dramatic improvement of proteinuria was noted. I.v.-IG should be fully considered in patients with steroid-resistant Henoch-Schonlein purpura nephritis.
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Affiliation(s)
- A Kusuda
- First Department of Internal Medicine, Nagasaki University School of Medicine, Sakamoto
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Degawa M, Hamasaki K, Yano K, Nakao K, Kato Y, Sakamoto I, Nakata K, Eguchi K. Refractory hepatic hydrothorax treated with transjugular intrahepatic portosystemic shunt. J Gastroenterol 1999; 34:128-31. [PMID: 10204623 DOI: 10.1007/s005350050228] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A 66-year-old cirrhotic woman was referred to our hospital for evaluation of refractory pleural effusion and dyspnea. Massive right sided-pleural effusion but no ascites was detected. She had been treated with diuretics and albumin, repeated thoracenteses, and pleural drainage with an intercostal catheter, all of which had failed to relieve her symptoms. The diagnosis of hepatic hydrothorax without ascites was made by injection of technetium-99m-sulfur colloid into the peritoneal cavity. A transjugular intrahepatic portosystemic shunt was placed and successfully reduced the pleural effusion, resulting in complete relief of her symptoms. The patient has been free of symptoms for 18 months after the procedure.
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Affiliation(s)
- M Degawa
- The First Department of Internal Medicine, Nagasaki University School of Medicine, Japan
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16
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Abstract
The neurotrophin-3 (NT-3) gene has previously been reported to consist of three exons including two 5' short untranslated exons and a 3' long exon encoding the entire protein, and to give rise to two classes of transcripts by alternative splicing of the 5' exons to the 3' coding exon. In the present study, we demonstrated the presence of at least four new classes of transcripts of the NT-3 gene, in addition to the two known transcripts. The present finding proposes the further complexity of the regulational mechanism for NT-3 expression.
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Affiliation(s)
- M Sekimoto
- Laboratory of Health Science, School of Pharmaceutical Sciences, University of Shizuoka, Japan
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17
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Tanaka H, Degawa M, Kawata E, Hayashi J, Shoyama Y. Identification of Cannabis pollens using an allergic patient's immunoglobulin E and purification and characterization of allergens in Cannabis pollens. Forensic Sci Int 1998; 97:139-53. [PMID: 9871993 DOI: 10.1016/s0379-0738(98)00152-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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: 10/18/2022]
Abstract
Cannabis pollen allergens were detected using the serum of an allergic patient. The allergens were then purified by sequential column chromatography (including DE52 cellulose and phenyl-Sepharose CL-4B) and preparative HPLC. The molecular weight of the allergens were determined as 10,050 and 13,706 by matrix-assisted laser desorption/ionization time of flight mass spectrometry. We utilised Western blotting and development of an enzyme-linked immunosorbent assay for the detection of Cannabis pollen allergens.
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Affiliation(s)
- H Tanaka
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Degawa M, Nakayama M, Konno Y, Masubuchi K, Yamazoe Y. 2-Methoxy-4-nitroaniline and its isomers induce cytochrome P4501A (CYP1A) enzymes with different selectivities in the rat liver. Biochim Biophys Acta 1998; 1379:391-8. [PMID: 9545601 DOI: 10.1016/s0304-4165(97)00118-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We reported previously that 2-methoxy-4-nitroaniline (2-MeO-4-NA) is a selective inducer of cytochrome P4501A2 (CYP1A2) in the rat liver, and its molecular size is the smallest among known CYP1A2-selective inducers. In the present study, a structure-activity relationship on the CYP1A2-selective induction has been investigated using isomeric nitroanisidines and their related chemicals. Western blot analyses revealed that the chemicals removed a substituent (amino, methoxyl or nitro group) from a 2-MeO-4-NA molecule had no capacity for inducing CYP1A enzymes in rat livers. On the other hand, isomeric nitroanisidines such as 2-MeO-4-NA, 2-MeO-5-NA and 4-MeO-2-NA induced both CYP1A2 and CYP1A1 enzymes with different selectivities. As judged from the induced levels of CYP1A proteins, 2-MeO-4-NA (CYP1A2/CYP1A1 ratio; 9.5) and 4-MeO-2-NA (0.3) were the most selective inducers of CYP1A2 and CYP1A1, respectively, among the isomeric nitroanisidines (0.44 mmol/kg) used. The induced level of CYP1A2 protein was in the order 2-MeO-4-NA > 2-MeO-5-NA > 4-MeO-2-NA, although no significant difference was observed on their CYP1A2 mRNA level. On the contrary, increases in the levels of CYP1A1 mRNA and protein were in the order 4-MeO-2-NA > 2-MeO-5-NA > 2-MeO-4-NA. The present findings indicate that all three substituents (amino, methoxyl and nitro groups) are necessary components of nitroanisidines for induction of CYP1A enzymes, and also show that regio-isomeric positions of these substituents determine the selectivity in the induction of CYP1A enzymes.
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Affiliation(s)
- M Degawa
- Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Imaoka S, Yoneda Y, Matsuda T, Degawa M, Fukushima S, Funae Y. Mutagenic activation of urinary bladder carcinogens by CYP4B1 and the presence of CYP4B1 in bladder mucosa. Biochem Pharmacol 1997; 54:677-83. [PMID: 9310344 DOI: 10.1016/s0006-2952(97)00216-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [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: 02/05/2023]
Abstract
We investigated the mutagenic activation of 2-naphthylamine (2-NA), 3,2'-dimethyl-4-aminobiphenyl (DMAB), and 3,3'-dichlorobenzidine (DCB), bladder carcinogens, by renal and bladder microsomes and by purified P450s using the umu gene expression system, which detects DNA damage. Mouse renal microsomes had high mutagenic activation toward DCB and low activity toward 2-NA. Purified mouse Cyp4b1 also had high mutagenic activity toward DCB. Anti-Cyp4b1 antibody efficiently inhibited DCB bioactivation by mouse renal microsomes with a high Cyp4b1 content. Lauric acid, a substrate of Cyp4b1, efficiently inhibited DCB bioactivation by renal and bladder microsomes of the mouse and by purified Cyp4b1. To assess the contribution of CYP4B1 to bladder carcinoma, further investigation was done with the umu test and an immunochemical study. Ten forms of purified rat P450s including rat CYP4B1 were used in the umu test for 2-NA, DMAB, and DCB. CYP4B1 had the highest activity toward DMAB and DCB. Other P450s had activities of less than 20% that of CYP4B1. CYP4B1 also activated 2-NA, but its activity was about 10% of that toward DMAB or DCB. Rat bladder epithelium was stained specifically with anti-Cyp4b1 antibody, indicating the presence of CYP4B1 in the rat bladder mucosa. Also, CYP4B1 mRNA was detected by northern blotting and reverse transcription-polymerase chain reaction (RT-PCR). These findings suggested that CYP4B1 could contribute to the initiation of carcinogenesis in rat and mouse bladder by activation of aromatic amines.
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Affiliation(s)
- S Imaoka
- Laboratory of Chemistry, Osaka City University Medical School, Osaka, Japan
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20
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Degawa M, Matsuda K, Arai H, Hashimoto Y. Lead nitrate inhibits the induction of CYP1A mRNAs by aromatic amines but not by aryl hydrocarbons in the rat liver. J Biochem 1996; 120:547-51. [PMID: 8902619 DOI: 10.1093/oxfordjournals.jbchem.a021448] [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: 02/02/2023] Open
Abstract
The effects of lead nitrate on the induction of hepatic cytochrome P450IA (CYP1A) isoforms, mainly CYP1A2, by aromatic amines (2-methoxy-4-aminoazobenzene, 2-amino-3-methyl-9H-pyrido [2,3-b]indole and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) and aryl hydrocarbons (3-methylcholanthrene, benzo[a]pyrene and beta-naphthoflavone) in male F344 rats were examined at the levels of mRNA, protein and activity of the enzymes. Pretreatment of rats with lead nitrate suppressed the expression of hepatic CYP1A enzyme(s), especially CYP1A2, at both levels of protein and activity of the enzyme(s) by treatment with an aromatic amine or an aryl hydrocarbon. On the other hand, the lead nitrate pretreatment suppressed the induction of CYP1A mRNA(s) by an aromatic amine but not by an aryl hydrocarbon. These findings indicate that lead nitrate suppresses the expression of CYP1A enzymes at both stages of post-translation of mRNAs and transcriptional activation of the genes, and further suggest that the pathway for the transcriptional activation of the CYP1A genes by the aromatic amines is different from that by the aryl hydrocarbons.
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Affiliation(s)
- M Degawa
- Faculty of Pharmaceutical Sciences, Tohoku University, Sendai
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21
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Uehara N, Iwahori Y, Asamoto M, Baba-Toriyama H, Iigo M, Ochiai M, Nagao M, Nakayama M, Degawa M, Matsumoto K, Hirono I, Beppu H, Fujita K, Tsuda H. Decreased levels of 2-amino-3-methylimidazo[4,5-f]quinoline-DNA adducts in rats treated with beta-carotene, alpha-tocopherol and freeze-dried aloe. Jpn J Cancer Res 1996; 87:342-8. [PMID: 8641964 PMCID: PMC5921102 DOI: 10.1111/j.1349-7006.1996.tb00228.x] [Citation(s) in RCA: 10] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To assess mechanisms of chemoprevention of hepatocarcinogenesis by trans-beta-carotene (beta-C), DL-alpha-tocopherol (alpha-T), and freeze-dried whole leaves of Kidachi aloe (Aloe), formation of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)-DNA adducts was measured by 32P-post-labeling analysis, and CYP1A1 and CYP1A2 protein levels were analyzed by ELISA. Group 1 rats were fed diet containing 0.02% beta-C, 1.5% alpha-T or 30% Aloe over an 8-day period, while group 2 was given basal diet alone. On day 7, all animals were subjected to two-thirds partial hepatectomy (PH). Twelve hours after PH, they received a single dose of the carcinogenic food pyrolysate IQ (100 mg/kg) intragastrically, to initiate hepatocarcinogenesis. Rats were killed 6, 12, 24 and 48 h after IQ administration. The levels of adducts, expressed as relative adduct labeling values in rats treated with beta-C, alpha-T and Aloe, were decreased as compared with the control group at hour 24 (36 h after PH), with a significant difference in the case of the beta-C group (46.4% of the control value). Similarly, all showed a tendency for decrease at hour 48. Furthermore, the levels of CYP1A2, known to be responsible for activation of IQ, showed a significant reduction at hour 24. It is concluded that beta-C, and possibly also alpha-T and Aloe, have the potential to reduce IQ-DNA adduct formation, presumably as a result of decreased formation of active metabolites. The results may explain, at least in part, the previously observed inhibitory effects of these compounds on induction of preneoplastic hepatocellular lesions.
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Affiliation(s)
- N Uehara
- Chemotherapy Division, National Cancer Center Research Institute, Tokyo, Japan
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Hashimoto Y, Degawa M. Induction of cytochrome P450 isoforms by carcinogenic aromatic amines and carcinogenic susceptibility of rodent animals. Pharmacogenetics 1995; 5 Spec No:S80-3. [PMID: 7581495 DOI: 10.1097/00008571-199512001-00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Hepatocarcinogenic aromatic amines such as 4-aminoazobenzene derivatives and heterocyclic aromatic amines of cooked food origin were found to be liver-selective cytochrome P450IAZ (CYP1A2) inducers. Each aromatic amine showed different species-specificity among rodent experimental animals in terms of the extent of P450 induction. Carcinogenic susceptibility of an animal to the amine was well correlated with the activity and/or inducibility of CYP1A2 in the animals in the early initiation phase of the carcinogenesis. In hyperplastic nodules of rat liver, expression and induction of CYP1A2 as suppressed, especially in the placental form of glutathione S-transferase-positive foci. Despite the decrease of P450s including CYP1A2 in the rat liver bearing hyperplastic nodules. DNA adducts formed by a carcinogenic aromatic amine increased, as compared to the controls, suggesting that the activity of DNA repair enzyme(s) for the amine-derived DNA adducts might decrease in the hyperplastic nodules of rat liver. Treatment of rats with lead nitrate revealed a pattern of P450 expression in the liver similar to that observed with rats bearing hyperplastic nodules. These findings may provide valuable information on the roles of P450s in carcinogenic susceptibility of animals to aromatic amines and in the carcinogenic process.
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Affiliation(s)
- Y Hashimoto
- Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Abstract
Male F344 rats were treated with a chemical (aniline, nitrobenzene, 2-methoxy-p-phenylenediamine, 2-methoxy-4-nitroaniline or 2-methoxy-4-nitroazobenzene) produced by the azo-reduction and/or N-oxidation of 2-methoxy-4-amino-azo-benzene, a selective inducer of cytochrome P450IA2 (CYP1A2), and their effects on the induction of CYP1A enzymes in the liver were examined in terms of the protein and mRNA amounts. 2-Methoxy-4-nitroaniline and 2-methoxy-4-nitroazo-benzene, but not other compounds tested, induced CYP1A enzymes, especially CYP1A2, as assessed by Western blotting and Northern blotting. It is noteworthy that 2-methoxy-4-nitroaniline was more selective than 2-methoxy-4-aminoazobenzene for induction of CYP1A2, and it has the smallest molecular size among the known CYP1A2 inducers.
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Affiliation(s)
- M Degawa
- Department of Hygineic Chemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Degawa M, Arai H, Kubota M, Hashimoto Y. Ionic lead, but not other ionic metals (Ni2+, Co2+ and Cd2+), suppresses 2-methoxy-4-aminoazobenzene-mediated cytochrome P450IA2 (CYP1A2) induction in rat liver. Biol Pharm Bull 1995; 18:1215-8. [PMID: 8845808 DOI: 10.1248/bpb.18.1215] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Male F344 rats were pretreated with lead nitrate, nickel chloride, cobalt chloride or cadmium chloride, and their effects on the induction of cytochrome P450 (CYP) enzymes, mainly CYP1A2 enzyme, with 2-methoxy-4-aminoazobenzene (2-MeO-AAB) in the livers were comparatively examined by enzymatical, immunochemical, and molecular biological methods. When rats were pretreated with each ionic metal, the total CYP amount in the liver microsomes decreased, as compared with that of rats treated with 2-MeO-AAB alone. However, among the ionic metals used only lead reduced the levels of the mRNA and protein of CYP1A2 induced with 2-MeO-AAB in the rat liver, and decreased the microsomal activity (per CYP) for CYP1A2-mediated mutagenesis. Furthermore, ionic lead, but not other ionic metals, showed an ability to induce a placental form of glutathione S-transferase (GST-P). The level of CYP1A2 induced with 2-MeO-AAB was decreased along with increase in that of the induced GST-P.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Imaoka S, Hiroi T, Tamura Y, Yamazaki H, Shimada T, Komori M, Degawa M, Funae Y. Mutagenic activation of 3-methoxy-4-aminoazobenzene by mouse renal cytochrome P450 CYP4B1: cloning and characterization of mouse CYP4B1. Arch Biochem Biophys 1995; 321:255-62. [PMID: 7639529 DOI: 10.1006/abbi.1995.1393] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [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: 01/26/2023]
Abstract
A new P450 responsible for mutagenic activation of 3-methoxy-4-aminoazobenzene (3-MeO-AAB) which is a potent procarcinogen was purified from renal microsomes of male mice using an index of umu gene expression. The purified P450 had high bioactivation toward 3-MeO-AAB and also 2-aminofluorene and 2-aminoanthracene. The antibody against this P450 completely inhibited mutagenic activation of 3-MeO-AAB of mouse renal microsomes. With immunoblotting, this form was present abundantly in renal microsomes of male mice but not in those of female mice. This P450 was also present in pulmonary microsomes of male and female mice but not in hepatic microsomes. The NH2-terminal amino acid sequence analysis indicated that this form belonged to the CYP4B subfamily. Thus, mouse kidney cDNA library was screened with rat CYP4B1 probe. The cDNA-deduced amino acid sequence of isolated cDNA consisted of 511 amino acids and bore 90, 86, and 84% similarities to rat, rabbit, and human CYP4B1, respectively. The NH2-terminal amino acid sequence of the purified renal P450 and amino acid sequence of BrCN-digested peptides from the purified P450 agreed with the cDNA-deduced amino acid sequence. These results suggest that CYP4B1 is a major form in renal microsomes of male mice and plays a major role in mutagenic activation of 3-MeO-AAB. In extrahepatic tissue, CYP4B1 may contribute to chemical carcinogenesis.
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Affiliation(s)
- S Imaoka
- Laboratory of Chemistry, Osaka City University Medical School, Japan
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26
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Abstract
Hyperplastic nodules of the liver were induced by treating male F344 rats with a combination of diethylnitrosamine and partial hepatectomy. The livers were examined for the expression of cytochrome P450 (CYP) enzymes, mainly CYP1A1 and CYP1A2; the amount and activity of the enzymes in the microsomes were assessed by enzymatic and immunological methods. Levels of CYP1A mRNAs were assayed by Northern blotting. In the liver bearing hyperplastic nodules, the total amount of microsomal CYP enzymes decreased to about 50% of the control. The microsomal activities for the CYP1A2-mediated activation of carcinogenic heterocyclic amines decreased to about 20% of the corresponding controls, in association with decreases in the levels of mRNA and protein of CYP1A2. Furthermore, the inducibility of CYP1A2 by CYP1A inducers such as 3-methoxy-4-aminoazobenzene and 3-methylcholanthrene was also decreased at the mRNA, protein and activity levels. On the other hand, CYP1A1 enzyme, which was undetectable in control rat liver, appeared in the liver bearing hyperplastic nodules, but its inducibility by a CYP1A inducer decreased slightly. The present findings indicated that individual CYP1A enzymes are differently regulated, and the expression of CYP1A2 is reduced preferentially in the liver bearing hyperplastic nodules.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai
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Degawa M. [Chemical carcinogenesis and cytochrome P450: carcinogenic aromatic amine-induced P450 and hepatocarcinogenic susceptibility to the aromatic amine in the rodent]. YAKUGAKU ZASSHI 1995; 115:1-14. [PMID: 7699577 DOI: 10.1248/yakushi1947.115.1_1] [Citation(s) in RCA: 4] [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: 01/26/2023]
Abstract
The N-hydroxyl and/or N-acetoxy derivatives of carcinogenic 4-aminoazo dyes, which were thought to be proximate and ultimate metabolites, were synthesized in our laboratory in 1975, and their chemical and biological characteristics were further examined. The results strongly supported the hypothesis that the metabolic conversions, N-hydroxylation and its O-acylation, of carcinogenic aromatic amines are important processes for their carcinogenicity. Carcinogenic aromatic amines such as heterocyclic aromatic amines and aminoazo dyes induced predominantly cytochrome P450IA2 (CYP1A2), which is responsible for the mutagenic activation and N-hydroxylation of the amines in the rodent. The induction rate and total activity of this enzyme were well correlated with sex, species, and target organ differences in hepatocarcinogenic susceptibility of animals to the aromatic amines. During hepatocarcinogenic process with an aromatic amine, the expression and induction of CYP1A2 decreased especially in preneoplastic liver cells as judged by the expression of a placental form of glutathione S-transferase.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Kojima M, Degawa M, Hashimoto Y, Tada M. The carcinogenicity of methoxyl derivatives of 4-aminoazobenzene: correlation between DNA adducts and genotoxicity. Environ Health Perspect 1994; 102 Suppl 6:191-194. [PMID: 7889846 PMCID: PMC1566856 DOI: 10.1289/ehp.94102s6191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To elucidate the cause of the difference in genotoxic activity between carcinogenic 3-methoxy-4-aminoazobenzene (3-MeO-AAB) and noncarcinogenic 2-methoxy-4-aminoazobenzene (2-MeO-AAB), we analyzed DNA adducts in the livers of rats exposed to either of these chemicals and studied the resulting biologic potential with the aid of in vitro modified M13 phage DNA. 32P-Postalbeling analysis revealed that the carcinogen 3-MeO-AAB produced 20-fold higher amounts of adducts than did 2-MeO-AAB. Five adducts were formed in the 3-MeO-AAB case whereas only one adduct was apparent in 2-MeO-AAB-treated rat. Studies of in vitro DNA replication using N-hydroxy (N-OH)-aminoazo dye-modified M13 phage DNA as a template demonstrated inhibition by 3-MeO-AAB adducts to be substantially greater than in the 2-MeO-AAB-adducts. The specificity of mutagenesis induced in M13mp9 phage DNA by these chemicals also was analyzed after transfection into SOS-induced Escherichia coli JM103, mutation frequencies being higher with N-OH-3-MeO-AAB- than N-OH-2-MeO-AAB-modified DNA. The mutation spectra differed in each case. Our data suggest that the difference in hepatocarcinogenic activity between the two chemicals depends not only on qualitative and quantitative variation in adduct formation but also on conformation changes in modified DNA.
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Affiliation(s)
- M Kojima
- Aichi Cancer Center Research Institute, Nagoya, Japan
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29
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Degawa M, Stern SJ, Martin MV, Guengerich FP, Fu PP, Ilett KF, Kaderlik RK, Kadlubar FF. Metabolic activation and carcinogen-DNA adduct detection in human larynx. Cancer Res 1994; 54:4915-9. [PMID: 8069857] [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: 01/28/2023]
Abstract
Putative carcinogen-DNA adducts in human larynx tissues (n = 25) from smoker and non/ex-smoker patients were examined by 32P-postlabeling and compared with the metabolic activation capacity of larynx microsomes and cytosols from the same tissues. Hydrophobic DNA adducts were evident only in smokers, and chromatographic profiles of the adducts were similar using either the butanol extraction or nuclease P1 enhancement method, which suggested that the adducts may be derived from polycyclic aromatic hydrocarbons but not aromatic amines. Immunoblots of larynx microsomes using anti-cytochrome P450 1A1/1A2, 2C, 3A4, 2E1, and 2A6 antibodies showed intensities ranging from 1-10% of that typically observed with human liver microsomes. Enzymatic assays of larynx microsomes showed appreciable activity for benzo(a)pyrene hydroxylation (P450 1A1 and 2C) but not for 4-aminobiphenyl N-oxidation (P450 1A2), which indicated that the observed immunoreactivity was for P450 1A1; this represents the highest level of this P450 yet detected in human extrahepatic tissues. Accordingly, total DNA adduct levels in the larynx correlated strongly with levels of P450 2C, 1A1, and 3A4 but not with P450 2E1 or 2A6. Larynx cytosols also showed appreciable aromatic amine N-acetyl-transferase activity for p-aminobenzoic acid (NAT-1) but not for sulfamethazine (NAT-2); however, NAT-1 activity was not correlated with total DNA adducts, which is again consistent with the lack of aromatic amine-DNA adducts detected by 32P-postlabeling. Thus, these results suggest that the DNA adducts detected in human larynx are largely derived from metabolic activation of polycyclic aromatic hydrocarbons in cigarette smoke by P450 2C, 3A4, and/or 1A1.
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Affiliation(s)
- M Degawa
- Office of Research (HFT-100), National Center for Toxicological Research, Jefferson, Arkansas 72079
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Degawa M, Arai H, Kubota M, Hashimoto Y. Ionic lead, a unique metal ion as an inhibitor for cytochrome P450IA2 (CYP1A2) expression in the rat liver. Biochem Biophys Res Commun 1994; 200:1086-92. [PMID: 8179586 DOI: 10.1006/bbrc.1994.1561] [Citation(s) in RCA: 16] [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: 01/29/2023]
Abstract
Male F344 rats were treated with lead nitrate, nickel chloride, cobalt chloride or cadmium chloride, and changes in the expression of cytochrome P450IA2 (CYP1A2) in the livers were assessed by enzymatical, immunochemical, and molecular biological methods. All ionic metals used significantly decreased total CYP amount in the liver microsomes. However, among ionic metals used only lead showed inhibitory effects on the microsomal activity for CYP1A2-dependent mutagenesis of aromatic amines and on the expression of mRNA and protein of the enzyme, indicating that ionic lead is a unique inhibitor for the expression of CYP1A2 enzyme in the rat liver.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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Degawa M, Kojima M, Yoshinari K, Tada M, Hashimoto Y. DNA adduct formation of hepatocarcinogenic aromatic amines in rat liver: effect of cytochrome P450 inducers. Cancer Lett 1994; 79:77-81. [PMID: 8187057 DOI: 10.1016/0304-3835(94)90066-3] [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: 01/29/2023]
Abstract
F344 rats were treated with an i.p. injection of 2-amino-6- methyldipyrido[1,2-a:3',2'-d]imidazole (Glu P-1) or 3-methoxy-4-aminoazobenzene (3-MeO-AAB) and examined for the formation of the DNA adduct in the liver. To examine the effect of pretreatment with a cytochrome P450 (CYP) inducer on the formation of DNA adduct, these rats were pretreated with 3-methylcholanthrene (MC; CYP1A1/1A2 inducer) or phenobarbital (PB; CYP2B inducer). Administration of Glu P-1 and 3-MeO-AAB gave 2 and 5 adducts, respectively, as determined by 32P-postlabeling assay. By Glu P-1 administration, pretreatment of rats with MC, but not with PB, increased the total amount of DNA adducts including 3 new adducts as minor products. In contrast, pretreatment of rats with PB increased the total amount of DNA adducts derived by 3-MeO-AAB. The increase of aromatic amine DNA adducts by pretreatment with a CYP inducer was proportional to the activity of induced CYP isozyme(s) responsible for the mutagenic activation of each aromatic amine.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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Degawa M, Mikami K, Namiki M, Hashimoto Y. Inhibition of the induction and activity of hepatic P450IA isozymes by in vivo administration of carbon tetrachloride to rats. Biol Pharm Bull 1993; 16:1248-50. [PMID: 8130776 DOI: 10.1248/bpb.16.1248] [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: 01/29/2023]
Abstract
The effect of carbon tetrachloride (CCl4) on the induction and activity of 3-methylcholanthrene (MC)-inducible P450IA isozymes (P450IA1 and P450IA2) in the liver was examined by treating male Sprague-Dawley rats with simultaneous i.p. injections of MC and CCl4. Following the treatment, the quantities of P450IA mRNAs determined by Northern blotting and P450IA proteins by Western blotting were significantly reduced as compared with those in rats treated with MC alone. As determined by a bacterial mutation test using carcinogenic aromatic amines are P450IA enzyme substrates, CCl4 treatment selectively inhibited the activity of P450IA2 in the MC-induced isozymes. These results indicate that CCl4 exerts on inhibitory effect on the induction of P4501A isozymes and that it selectively inhibits P450IA2 activity.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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Abstract
Effects of nivalenol (NIV), a trichothecene mycotoxin, on hepatic drug-metabolizing activity and aflatoxin B1 (AFB1) metabolism were investigated in male rats. In rats fed the diets containing 6-12 ppm NIV for 2 or 4 wk, decreases in initial feed uptake, terminal weight gain and organ weights were evident. An increase in cytochrome P-450 activity was observed in the hepatic microsomes, and Western blot analysis revealed a transient increase in P4502B1/2, together with a slight induction of P4501A2. The activity of cytosolic glutathione S-transferase (GST) enzymes was also enhanced in the rats, and Western blot analysis demonstrated an elevation of GST 1-2. The formation of aflatoxin B1-DNA adducts (AFB1-DNA) was increased in experiments using hepatic microsomal preparations from rats fed the NIV diet, whereas supplementation with cytosol prepared from NIV-treated rats reduced the microsomal potential for adduct formation. In in vivo experiments, the AFB1-DNA concentration in NIV-treated rats was lower than that in the controls. These results suggest that activities of cytochrome P-450 and GST enzymes were increased in rats fed NIV for several weeks. Alteration of these phase I and phase 2 enzyme levels resulted in the modulation of AFB1 adduction to DNA in vitro and in vivo.
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Affiliation(s)
- T Yabe
- Department of Toxicology and Microbial Chemistry, Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan
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Abstract
Male F344 rats were treated with lead nitrate and changes in the expression and induction of P450IA subfamily enzymes and a placental form of glutathione-S-transferase (GST-P) in the liver were assessed by means of a bacterial mutation test, immunoblotting with a monoclonal antibody reactive to P450IA1/IA2 and anti-GST-P sera and Northern blotting with P450IA2 cDNA as a probe. Treatment of rats with lead nitrate (20, 50 or 100 mumol/kg body wt) decreased P450IA2 mRNA and protein in the liver in the dose-dependent fashion and also decreased the microsomal activity for P450IA2-dependent mutagenization of aromatic amines. Pretreatment of rats with lead nitrate suppressed the inductions of both P450IA2 mRNA and protein by an inducer of P450IA subfamily enzymes in the liver. In addition, amount of the induced P450IA2 was decreased along with increase in that of the induced GST-P.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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35
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Stern SJ, Degawa M, Martin MV, Guengerich FP, Kaderlik RK, Ilett KF, Breau R, McGhee M, Montague D, Lyn-Cook B. Metabolic activation, DNA adducts, and H-ras mutations in human neoplastic and non-neoplastic laryngeal tissue. J Cell Biochem Suppl 1993; 17F:129-37. [PMID: 8412184 DOI: 10.1002/jcb.240531018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Metabolic activation, DNA adducts, and H-ras mutations were examined in human laryngeal tissue (n = 16) from both smoker and non/ex-smoker patients with laryngeal cancer. DNA adducts detected by 32P-postlabelling were evident only in smokers (n = 13); in fact, smoking cessation for as little as 10 months resulted in no DNA adducts detected (n = 3). Total DNA adduct levels in these samples were significantly correlated with levels of cytochromes P-4502C and 1A1 in laryngeal microsomes. Moreover, the P-4501A1 levels represent the highest yet found in human tissues. In contrast, laryngeal microsomes did not have detectable P-4501A2 activity, while laryngeal cytosols showed appreciable N-acetyltransferase activity for p-aminobenzoic acid (NAT1) but not sulfamethazine (NAT2). DNA was extracted from laryngeal specimens and amplified by PCR. Nylon filter dot or slot blots were hybridized with 32P-labelled probes for codons 12, 13, and 61 of the H-ras gene. Sixty percent of specimens demonstrated mutations in either codon 12, 13, or 61; a single common and specific mutation was a Gln-->Glu transversion in codon 61. This mutation appeared in 5 laryngeal specimens, all from smokers. These results implicate cigarette smoke components, bioactivated by CYP1A1 and/or CYP2C, in DNA adduct formation. These results also demonstrate a probable smoking-related H-ras Gln-->Glu transversion in codon 61.
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Affiliation(s)
- S J Stern
- University of Arkansas for Medical Sciences, Department of Otolaryngology--Head and Neck Surgery, Little Rock 72205
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36
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Degawa M, Kobayashi K, Miura S, Arai H, Esumi H, Sugimura T, Hashimoto Y. Species difference among experimental rodents in induction of P450IA family enzymes by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine. Jpn J Cancer Res 1992; 83:1047-51. [PMID: 1452456 PMCID: PMC5918673 DOI: 10.1111/j.1349-7006.1992.tb02720.x] [Citation(s) in RCA: 14] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Rats, mice, hamsters and guinea pigs were given an i.p. injection of 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP), a protein-derived pyrolysate component present in cooked foods, and inductions of cytochrome P450 (P450) in the liver and kidney of these animals were examined. The activity and amount of P450s corresponding to the rat P450IA1 and P450IA2 were assessed by means of a bacterial mutation test using 3 carcinogenic heterocyclic aromatic amines including PhIP as substrates and by Western blotting with a monoclonal antibody reactive with both P450IA1 and P450IA2. In rats, PhIP induced P450IA1, P450IA2 and a new but unspecified P450 isozyme in the liver, and induced P450IA1 in the kidney. However, PhIP induced none of these P450 isozymes in mice, hamsters and guinea pigs.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai
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Kojima M, Morita T, Degawa M, Hashimoto Y, Tada M. Differences in DNA damage induced by mutagenic and nonmutagenic 4-aminoazobenzene derivatives in Escherichia coli. Mutat Res 1992; 274:65-71. [PMID: 1375333 DOI: 10.1016/0921-8777(92)90044-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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: 12/26/2022]
Abstract
DNA lesions produced in Escherichia coli AB2500 (uvrA) exposed to the carcinogen N-hydroxy-3-methoxy-4-aminoazobenzene (N-OH-3-MeO-AAB) or the noncarcinogen N-hydroxy-2-methoxy-4-aminoazobenzene (N-OH-2-MeO-AAB) were investigated by alkaline sucrose gradient sedimentation and 32P-postlabeling analysis. Alkali-labile sites appeared to be formed equally in cells treated with both aminoazobenzene derivatives. 32P-Postlabeling analysis revealed that the 3-MeO-AAB-DNA adduct level was 25-fold higher than that for 2-MeO-AAB-DNA adducts. In addition to major adducts, 4 minor spots were detected in N-OH-3-MeO-AAB-treated cells, while only one major adduct was found in N-OH-2-MeO-AAB-treated cells. The mutagenicities and cytotoxicities were also determined with E. coli with different repair capacities; we found that repair of 3-MeO-AAB damages is strongly dependent on the UVR repair system. Moreover, N-OH-3-MeO-AAB, but not N-OH-2-MeO-AAB, could induce recA and umuC gene expression, which was higher in uvrA strains than in the wild type.
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Affiliation(s)
- M Kojima
- Laboratory of Biochemistry, Aichi Cancer Center Research Institute, Nagoya, Japan
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38
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Abstract
Antibodies to 3-methoxy-4-aminoazobenzene (3-MeO-AAB) and 2-methoxy-4-aminoazobenzene (2-MeO-AAB) DNA adducts were raised in rabbits against in vitro-adducted DNA samples. The enzyme-linked immunosorbent assay (ELISA) was used to determine the sensitivity and specificity of these antibodies. They proved highly specific for the modified DNA used as the immunogen, but cross-reacted with each other. Moreover, they showed cross reactivity with DNA modified by 4-(o-tolylazo)-o-toluidine, but not by other carcinogens, such as 4-aminobiphenyl or 4-nitroquinoline 1-oxide. The 50% inhibition level of antibody binding in the competitive ELISA was at 10-20 fmol of modified base per assay (equivalent to 1-2 adducts per 10(6) bases). Immunohistochemical staining indicated that these antibodies bind specifically to nuclear components of the liver in rats given either 3-MeO-AAB or 2-MeO-AAB at the dose of 50 mg/kg body weight.
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Affiliation(s)
- M Kojima
- Laboratory of Biochemistry, Aichi Cancer Center Research Institute, Nagoya
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39
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Abstract
The change of cytochrome P450 (P450) isozymes in a early stage of hepatocarcinogenesis in male F344 rats has been studied. Liver microsomes were prepared from normal rats (group 1), rats treated with diethylnitrosamine (DEN) alone, which developed no hyperplastic nodules (group 2), and rats treated with DEN plus 2-acetylaminofluorene, which developed many hyperplastic nodules (group 3). The amount and activity of P450IA1 and P450IA2 expressed in the liver were analyzed by several immunological methods using monoclonal antibodies against the P450 isozymes and a mutagenicity test. In the group 2 and 3 rats, the total amount of P450 and the amount of P450IA2 were much smaller than those in the group 1 rats, and P450IA1 was detected only from the group 3 rats. As observed by immunohistochemistry, P450IA1 was prominent in hyperplastic nodules developed in the group 3 rats, and the distribution of P450IA1+ cells in individual nodules was heterogeneous. When the rats were treated with a P450 inducer, 3-methoxy-4-aminoazobenzene or 3-methylcholanthrene, both P450IA1 and P450IA2 were induced in all groups of rats; however, the induction rates of the P450 isozymes, especially that of P450IA2, in the group 3 rats were smaller than those in the group 1 and 2 rats. The present work demonstrated that P450IA1, which is responsible mainly for detoxication of aromatic amine carcinogens, increased in level along with the development of hyperplastic nodules, whereas P450IA2, which is responsible for mutagenic or carcinogenic activation of these carcinogens, decreased in its amount and inducibility.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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40
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Abstract
Activities of the renal and hepatic microsomal enzymes responsible for the N-hydroxylation and mutagenic activation of 3-methoxy-4-aminoazobenzene (3-MeO-AAB) were examined in male mice, rats, hamsters and guinea pigs. In all these rodent species, hepatic microsomes showed definite N-hydroxylation of 3-MeO-AAB, whereas the renal activity was detected only in mice. The hepatic enzyme responsible for N-hydroxylation of 3-MeO-AAB (3-MeO-AAB N-hydroxylase) was induced in all species except mice by phenobarbital and selectively in mice and hamsters by 3-methylcholanthrene, whereas these cytochrome P450 inducers did not affect the renal enzyme in mice, rats or hamsters. In individual microsome samples, activities for N-hydroxylation and mutagenic activation of 3-MeO-AAB correlated well. These results indicate that the renal and hepatic enzymes responsible for the metabolic activation of 3-MeO-AAB differed among different species of rodent animals in terms of their activity and inducibility with cytochrome P450 inducers.
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Affiliation(s)
- S Miura
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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41
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Kojima M, Degawa M, Hashimoto Y, Tada M. Different effects of DNA adducts induced by carcinogenic and noncarcinogenic azo dyes on in vitro DNA synthesis. Biochem Biophys Res Commun 1991; 179:817-23. [PMID: 1898405 DOI: 10.1016/0006-291x(91)91890-o] [Citation(s) in RCA: 17] [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: 12/29/2022]
Abstract
M13mp10 phage DNA modified with the carcinogen 3-methoxy-4-aminoazobenzene (3-MeO-AAB) or the noncarcinogen 2-methoxy-4-aminoazobenzene (2-MeO-AAB) was used as a template for E.coli DNA polymerase I. Analysis of the reaction products on DNA sequencing gels showed that with both types of compound the induced lesions blocked DNA synthesis, mainly at one base prior to guanine adducts, but that the inhibition by 3-MeO-AAB-adducts was substantially greater than that by 2-MeO-AAB-adducts. Thus different effects on DNA replication between 3-MeO-AAB- and 2-MeO-AAB-adducts might be a reflection of differences in their carcinogenic potency.
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Affiliation(s)
- M Kojima
- Laboratory of Biochemistry, Aichi Cancer Center Research Institute, Nagoya, Japan
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Kojima M, Degawa M, Hashimoto Y, Tada M. 32P-postlabeling analysis of DNA adducts in rat livers after treatment with genotoxic and non-genotoxic 4-aminoazobenzene derivatives. Cancer Lett 1991; 58:199-204. [PMID: 1855196 DOI: 10.1016/0304-3835(91)90101-m] [Citation(s) in RCA: 7] [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
Formation of hepatic DNA adducts was studied in rats following intraperitoneal administration of a hepatocarcinogen, 3-methoxy-4-aminoazobenzene (3-MeO-AAB) and a non-hepatocarcinogen, 2-methoxy-4-aminoazobenzene (2-MeO-AAB). The 32P-post-labeling assay revealed 3-MeO-AAB to give more than 20-fold higher amounts of DNA adducts than did 2-MeO-AAB. Furthermore, five adducts, one of which accounted for over 70% of the total modified bases, were found in DNA from 3-MeO-AAB-treated rats, whereas only one adduct was apparent in 2-MeO-AAB-treated DNA. Our data thus suggested that the difference in hepatocarcinogenic activity between 3-MeO-AAB and 2-MeO-AAB might be, at least in part, dependent on quantitative and qualitative differences in their azo dye-DNA adduct formation in the rat liver.
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Affiliation(s)
- M Kojima
- Laboratory of Biochemistry, Aichi Cancer Center Research Institute, Kanokoden, Nagoya, Japan
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Adachi H, Degawa M, Miura S, Hashimoto Y, Sugimura T, Esumi H. Induction of putative new cytochrome P450 isozyme in rat liver by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine. Biochem Biophys Res Commun 1991; 174:797-803. [PMID: 1993073 DOI: 10.1016/0006-291x(91)91488-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [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]
Abstract
Changes in hepatic enzymes responsible for mutagenic activation of food mutagens-carcinogens by treatment with 2-amino-1-methyl-6-phenylimidazo [4, 5-b]pyridine (PhIP) in male F344 rats were examined using the Salmonella mutation test, with 3 heterocyclic aromatic amines as substrates, and further characterized by Western blot analysis with anti-P450 monoclonal antibodies (MoAbs) against rat P450IA1 and P450IA2. Enzymatical and immunochemical analyses indicated that PhIP could induce a putative new P450 isozyme, mol. wt., 51,000, together with P450IA1 and P450IA2 in rat liver microsomes. The profiles of induced P450 molecular species varied dramatically, depending on the time after PhIP administration.
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Affiliation(s)
- H Adachi
- Biochemistry Division, National Cancer Center Research Institute, Tokyo, Japan
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Yamazaki H, Degawa M, Funae Y, Imaoka S, Inui Y, Guengerich FP, Shimada T. Roles of different cytochrome P450 enzymes in bioactivation of the potent hepatocarcinogen 3-methoxy-4-aminoazobenzene by rat and human liver microsomes. Carcinogenesis 1991; 12:133-9. [PMID: 1988174 DOI: 10.1093/carcin/12.1.133] [Citation(s) in RCA: 15] [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] [Indexed: 12/29/2022] Open
Abstract
The potent hepatocarcinogen 3-methoxy-4-aminoazobenzene (3-MeO-AAB) has been reported to be bioactivated to mutagenic intermediates by rat liver microsomal cytochrome P450 (P450) and to be a selective inducer of rat P450IA2. In this study we have further investigated the roles of individual rat and human P450 enzymes in the bioactivation of this hepatocarcinogen in a Salmonella typhimurium TA1535/pSK1002 system where umu response is indicative of DNA damage. 3-MeO-AAB was found to be bioactivated by liver microsomal enzymes from rats and humans in this assay system. The liver microsomal activities are increased by pretreatment of rats with various P450 inducers such as phenobarbital (PB), beta-naphthoflavone (BNF), dexamethasone (DEX), acetone, ethanol, isoniazid (INH), diphenylhydantoin and valproic acid, and can be inhibited considerably by SKF-525A and metyrapone. alpha-Naphthoflavone (ANF) is also an inhibitor for the reaction catalyzed in BNF-treated rats, but stimulated the microsomal activity in DEX-treated rats. Evidence has also been obtained that specific antibodies raised against P450IIB1, P450IA1 or IA2, P450IIE1, and P450IIIA2 inhibited the activation in liver microsomes from rats pretreated with PB, BNF, INH and DEX respectively, suggesting the possible roles of several P450 enzymes in the bioactivation of 3-MeO-AAB. The results obtained with reconstituted monooxygenase systems containing various rat P450 enzymes are highly supportive of this conclusion. Human liver microsomal activation of 3-MeO-AAB was also inhibited to various extents by antibodies raised against P450IA2, P450MP, P450IIE1 and P450IIIA4. In a reconstituted system containing purified forms of human P450, P450IA2 was the most active in catalyzing 3-MeO-AAB, followed by P450IIIA4 and P450MP. ANF, a known activator of P450IIIA-catalyzed reactions, caused an increase in activation of 3-MeO-AAB in human liver microsomal and P450IIIA4- and P450MP-containing reconstituted systems. From these results it is concluded that multiple P450 enzymes in rat and human liver microsomes are involved in the bioactivation of 3-MeO-AAB, regardless of its selective induction of the rat P450IA2 gene.
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Affiliation(s)
- H Yamazaki
- Osaka Prefectural Institute of Public Health, Japan
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45
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Degawa M, Agatsuma T, Hashimoto Y. Species difference among experimental rodents in the activity and induction of cytochrome P-450 isozymes for mutagenic activation of carcinogenic aromatic amines. Jpn J Cancer Res 1990; 81:1253-8. [PMID: 2125995 PMCID: PMC5918006 DOI: 10.1111/j.1349-7006.1990.tb02687.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] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The expressions of hepatic microsomal cytochrome P-450 isozymes in male rats, mice, hamsters and guinea pigs were studied comparatively with or without an ip injection of a cytochrome P-450 inducer. The activity and quantity of microsomal cytochrome P-450 isozymes were determined respectively by a bacterial mutation assay with Salmonella typhimurium TA98 and immunochemical assays using monoclonal antibodies against rat cytochrome P-450 isozymes. 3-Methoxy-4-aminoazobenzene (3-MeO-AAB), 2-amino-3-methyl-9H-pyrido[2,3-b]indole acetate (MeA alpha C) and 3-methylcholanthrene were used as cytochrome P-450 inducers, and 7 carcinogenic aromatic amines including 3-MeO-AAB and MeA alpha C were used as substrates for the mutation assay. By means of these assays, we examined the species differences among rodents in the activity and induction rate of hepatic cytochrome P-450 isozymes responsible for the mutagenic activation of carcinogenic aromatic amines.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai
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46
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Degawa M, Miura S, Hashimoto Y. Androgen-dependent renal microsomal cytochrome P-450 responsible for N-hydroxylation and mutagenic activation of 3-methoxy-4-aminoazobenzene in the BALB/c mouse. Cancer Res 1990; 50:2729-33. [PMID: 2328499] [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: 12/31/2022]
Abstract
A murine renal microsomal enzyme responsible for the mutagenic activation of 3-methoxy-4-aminoazobenzene (3-MeO-AAB) was characterized by its catalytic activity for the mutagenic and metabolic conversion of 3-MeO-AAB. Incubation of 3-MeO-AAB with a renal or hepatic microsome fraction from male BALB/c mice in the presence of NADPH and NADH yielded N-hydroxy and 4'-hydroxy metabolites of 3-MeO-AAB as determined by two-dimensional thin layer chromatography, and the enzyme responsible for the N-hydroxylation was named 3-MeO-AAB N-hydroxylase. A mutagenicity test using Salmonella typhimurium TA98 bacteria as a tester strain has revealed that N-hydroxy-3-MeO-AAB is a potent direct mutagen but that 4'-hydroxy-3-MeO-AAB is not mutagenic. Although 3-MeO-AAB N-hydroxylase activity in liver microsomes showed no sex difference, the enzyme activity in the kidney was detected from male mice but not from females. However, administration of testosterone to female mice induced the enzyme in the kidney. Castration of male mice depressed the activity of 3-MeO-AAB N-hydroxylase in renal microsomes but it little affected the hepatic activity, and on administration of testosterone to the castrated mice the depressed renal microsomal activity recovered to a normal level. The activity of 3-MeO-AAB hydroxylase and the amount of cytochrome P-450 in renal microsomes showed a close correlation. Both renal and hepatic microsomes required NADPH as a main cofactor to mutagenize 3-MeO-AAB and to yield N-hydroxy-3-MeO-AAB from 3-MeO-AAB, and the enzyme activity was strongly inhibited by 7,8-benzoflavone. When the activities of renal and hepatic 3-MeO-AAB N-hydroxylase were compared on the basis of the amount of cytochrome P-450, the renal type enzyme showed about 8 times greater activity than hepatic type enzyme. These results indicate that the kidney contains an androgen-dependent microsomal 3-MeO-AAB hydroxylase which is different from an isozyme present in the liver and which is a new type of cytochrome P-450 isozyme.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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47
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Degawa M, Tanimura S, Agatsuma T, Hashimoto Y. Hepatocarcinogenic heterocyclic aromatic amines that induce cytochrome P-448 isozymes, mainly cytochrome P-448H (P-450IA2), responsible for mutagenic activation of the carcinogens in rat liver. Carcinogenesis 1989; 10:1119-22. [PMID: 2720904 DOI: 10.1093/carcin/10.6.1119] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [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: 01/02/2023] Open
Abstract
Male F344 rats were treated with hepatocarcinogenic heterocyclic aromatic amines such as amino acid- and protein-pyrolysate components (Trp P-1, Trp P-2, Glu P-1, Glu P-2, A alpha C, MeA alpha C, IQ and MeIQx) and changes in microsomal cytochrome P-450 isozymes in the livers were examined by means of immuno-Western blotting using anti-rat cytochrome P-450 monoclonal antibodies. The results suggested that all chemicals tested induce cytochrome P-448 isozymes, particularly cytochrome P-448H (P-450IA2), which efficiently mediate mutagenic activation of the carcinogens. This was substantiated by the enzymatic analyses with the substrates showing different characters to rat cytochrome P-450 isozyme-mediated mutagenesis.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Pharmaceutical Institute, Tohoku University, Sendai, Japan
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48
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Abstract
Hepatocytes from male Sprague-Dawley rats pretreated with a cytochrome P-450 inducer, 3-methoxy-4-aminoazobenzene (3-MeO-AAB), 3-methylcholanthrene (MC) or phenobarbital (PB), were cultured in vitro, and changes in the quantity and activity of microsomal cytochrome P-450 isozymes in the cells were determined by means of immunochemical methods and a bacterial mutation test, respectively. The results of enzyme-linked immunosorbent assay using monoclonal antibodies against rat P-450 isozymes revealed that the amount of cytochrome P-450d induced by 3-MeO-AAB or MC declined rapidly during culture and fell to 10 to 15% of the initial value after 24 h. A similar tendency was observed with PB-induced cytochrome P-450b/e. By contrast, cytochrome P-450c in MC-induced hepatocytes declined more slowly than cytochrome P-450d and remained at 45 to 60% of the initial value after 24 h. Similar quantitative changes of the individual cytochrome P-450 isozymes in culture were also observed by immunoblotting using the anti-cytochrome P-450 monoclonal antibodies. Changes in the activities of individual cytochrome P-450 isozymes in hepatocytes by culture were in accordance with the quantitative changes of the cytochromes, as determined by a mutation test using Salmonella typhimurium TA 98 and carcinogenic aromatic amines. These results indicate that microsomal cytochrome P-450c in primary cultured rat hepatocytes is more stable in culture, in terms of both quantity and activity, than cytochrome P-450d and P-450b/e.
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Affiliation(s)
- M Namiki
- Department of Hygienic Chemistry, Tohoku University, Sendai
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49
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Degawa M, Ueno H, Miura S, Ohta A, Namiki M. A simple method for assessment of rat cytochrome P-448 isozymes responsible for the mutagenic activation of carcinogenic chemicals. Mutat Res 1988; 203:333-8. [PMID: 3173384 DOI: 10.1016/0165-1161(88)90029-5] [Citation(s) in RCA: 19] [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: 01/04/2023]
Abstract
Cytochrome P-448H/L-enriched and cytochrome P-448L-enriched microsomes were prepared from the livers of Sprague-Dawley rats treated with 3-methylcholanthrene (MC) and with a combination of MC and carbon tetrachloride, respectively, and their activities for mediating mutagenic activation of 9 carcinogenic aromatic amines and benzo[a]pyrene, which are found to be different from cyt. P-450 isozymes as to mutagenic activation, were compared on the basis of microsomal cytochrome P-450 content using Salmonella typhimurium TA98 as a tester bacterium. With regard to the substrate-specificity of cytochrome P-448 isozymes, the present results reflected the reported results with use of a cytochrome P-450-reconstituted system. These findings indicate that the mutation test with cytochrome P-448H/L-enriched and cytochrome P-448L-enriched microsomes could be used as a simple method for the determination of the cytochrome P-448 isozymes responsible for the mutagenic activation of carcinogens and mutagens without the use of a cytochrome P-450-reconstituted system.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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50
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Degawa M, Namiki M, Miura S, Ueno H, Hashimoto Y. A male-specific renal cytochrome P-450 isozyme(s) responsible for mutagenic activation of 3-methoxy-4-aminoazobenzene in mice. Biochem Biophys Res Commun 1988; 152:843-8. [PMID: 3365254 DOI: 10.1016/s0006-291x(88)80115-3] [Citation(s) in RCA: 3] [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: 01/05/2023]
Abstract
Renal microsomes from male mice (BALB/c, DBA/2 and BALB/c x DBA/2 F1) showed about 10-fold greater activity for mediating mutagenic activation of 3-methoxy-4-aminoazobenzene (3-MeO-AAB) toward Salmonella typhimurium TA98 than did the corresponding hepatic microsomes, as compared on the basis of nmol of microsomal cytochrome P-450. On the other hand, female renal microsomes and other extrahepatic microsomes (lung, small intestine and colon) in both sexes of mice showed little or no activity for converting 3-MeO-AAB to mutagen(s). The mutagenic activation of 3-MeO-AAB with the male renal enzyme(s) was definitely inhibited by cytochrome P-450 inhibitors, 7,8-benzoflavone and SKF 525A. All these findings suggest that in mice, there is a male-specific renal 3-MeO-AAB activation enzyme(s), a cytochrome P-450 isozyme(s), which is different, at least in proportion and/or in nature, from hepatic cytochrome P-450 isozymes.
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Affiliation(s)
- M Degawa
- Department of Hygienic Chemistry, Tohoku University, Sendai, Japan
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