* Department of Physiology and Pharmacology, University of Queensland, Queensland 4072, Australia;
Division of Clinical Pharmacology and Toxicology, Research Institute, The Hospital for Sick Children, Toronto, Canada M5G 1X8;
Department of Histopathology, Flinders University of South Australia, SA, 5042 Australia; and
§ Pathology Department, Royal Brisbane Hospital, Queensland 4006, Australia
Received June 24, 1999; accepted October 20, 1999
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ABSTRACT |
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Key Words: N-acetyltransferase; carcinogenesis; hybridization histochemistry; liver; bladder..
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INTRODUCTION |
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The human NAT isozymes are encoded at 3 separate loci, one of which (NATP) contains multiple premature termination codons and most likely represents a non-expressed pseudogene (Blum et al., 1990). The two expressed genes, NAT1 and NAT2, are both located on chromosome 8 and share 87% and 81% nucleotide and amino acid sequence identity, respectively. Although only 10% of the amino acid-sequence differences between NAT1 and NAT2 were identified as non-conservative, functional studies have demonstrated significant differences between the two isozymes. NAT1 preferentially metabolizes p-aminobenzoate and p-aminosalicylate, and has traditionally been designated as the "monomorphic" form. Recent studies, however, have identified allelic variants of NAT1, one of which has been associated with elevated enzyme activity in preliminary studies (Bell et al., 1995
). At least 15 and perhaps as many as 23 different allelic variants of NAT2 have been identified to date, and their frequency in the population provides a molecular explanation for the polymorphic metabolism of model substrates such as sulfamethazine and procainamide (Grant et al., 1991
, 1997
; Grant, 1993
; Hein et al., 1997
). The representation of these mutant alleles also differs widely between populations of different ethnic or geographical location (Grant et al., 1997
), with slow acetylators accounting for 10% and 4070% of Oriental and Caucasian populations, respectively (Deguchi et al., 1990
; Hickman and Sim, 1991
).
An ever-increasing number of studies have demonstrated an association between the NAT2 phenotype/genotype and drug toxicities. One group recently proposed that discoid lupus erythematosus is responsive to sulfasalazine therapy only in rapid acetylators and that slow acetylators show increased toxicity to this drug (Sabbagh et al., 1997). Individual predisposition to certain forms of cancer has also been linked to the NAT2 phenotype/genotype. The slow NAT2 acetylator phenotype is associated with an increased risk of bladder cancer in smokers whereas the rapid acetylator phenotype is over-represented in patients with colorectal cancer (Brockmöller et al., 1996
; Ilett et al., 1987
). Another study has shown that carriers of the NAT2*4/*4 genotype, which results in a high acetylation capacity, are at a significantly increased risk of lung cancer (Cascorbi et al., 1996
).
NAT1 expression is widely distributed throughout the human body, whereas NAT2 expression is considered to be more limited. Both forms have been identified by activity studies to be present not only in the liver but also in other tissues such as gut, uroepithelial cells, and lymphocytes (Coroneos and Sim, 1991; Cribb et al., 1991
; Kirlin et al., 1991
; Kloth et al., 1994
; Pink et al., 1992
). However, because of the overlapping substrate specificities and the unresolved functional significance of allelic variants of NAT1 and NAT2, one must use caution when interpreting tissue localization of these isozymes based on metabolic activities. Weber and Vatsis, in a recent review, also commented on the potential limitations of using data from heterologous expression systems to determine the relative importance of NAT1 versus NAT2 in the activation of aromatic and heterocyclic amines (Weber and Vatsis, 1995
).
Despite the evidence of NAT1 and NAT2 activity in various human tissue types, little is known about their cellular localization. In this study, we have used hybridization histochemistry to characterize NAT1 and NAT2 expression at the mRNA level in both hepatic and extrahepatic human tissues. Mapping of the distribution of NAT mRNA in human tissues will not only provide information concerning their cellular localization, but also aid in the understanding of their relative roles in site-specific tumorigenesis.
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MATERIALS AND METHODS |
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Hybridization probes.
All enzymes and reagents required for the transcription of RNA probes were obtained from Stratagene (La Jolla, CA). RNA probes were transcribed from NAT1 and NAT2 genomic DNA sequences subcloned into the Bluescript SK transcription plasmid. The NAT1 insert was a 145-bp EcoRI-DdeI restriction fragment corresponding to bases 153 to 8 (relative to the translation start site) of the NAT1 transcript's 5' non-coding region. The NAT2 insert was a 313-bp BamHI-EcoRI fragment corresponding to bases +856 to +1169. The recombinant plasmids were linearized and subjected to proteinase-K digestion prior to RNA probe synthesis. Both antisense and sense probes were transcribed from each plasmid for use as test and control probes respectively. Riboprobes for hybridization histochemistry were labeled by incorporation of [-35S]UTP (Du Pont, Australia).
To verify probe specificity, EcoRI digests of NAT1 and NAT2 DNA were prepared from Bluescript plasmids containing the protein-coding and flanking regions of the NAT1 (1.3 kb) and NAT2 (1.9 kb) inserts (Blum et al., 1990). The EcoRI digests spanning the NAT1 and NAT2 genes were also used as templates for polymerase chain reaction (PCR) experiments using primers designed to amplify the specific NAT1 (145 bp) or NAT2 (313 bp) regions. The EcoRI digests of human genomic DNA spanning the NAT1 and NAT2 genes and the PCR-amplified NAT1 and NAT2 DNA were tested against the NAT1 and NAT2 probes in a standard Southern blot procedure. NAT1- and NAT2-specific probes were labeled with 32P (Amersham, UK) using an Oligolabelling Kit (Pharmacia Biotech, USA). Probe hybridization was performed using standard protocols with 1 x 106 cpm of radiolabeled probe added to each blot and hybridization performed at 60°C overnight. Non-specific binding of the probe to the membrane was removed by sequential washes of increasing stringency to a final wash in 1 x SSC (150 M NaCl, 15 mM Na3 citrate) at 60°C. Autoradiographs were exposed for 80 min at room temperature.
Hybridization histochemistry.
The hybridization histochemistry procedure was performed on formalin-fixed, paraffin-embedded sections as described previously (McKinnon et al., 1991). Two serial sections were included on each slide for probing with test (antisense) and control (sense) probes, respectively. For the hybridization histochemistry studies, at least four samples were tested for each tissue sample. A high stringency wash was necessary to reduce background with the riboprobes and was performed in 0.1x SSC (15 M NaCl, 1.5mM Na3citrate) containing 30% formamide at 53°C and 55°C for NAT1 and NAT2 probes, respectively. All test sections were evaluated by direct comparison with a control section present on the same slide that had been hybridized with the sense probe. Control sections demonstrated few, or no, autoradiographic grains that were uniformly distributed across the section and these were interpreted as background. By comparison, test sections hybridized with antisense probe exhibited autoradiographic signal at higher levels than those of the control section and this was documented as a positive result.
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RESULTS |
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DISCUSSION |
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The observation of NAT1 and NAT2 mRNA expression along the gastrointestinal tract is supported by numerous NAT activity studies in human and animal models (Bell et al., 1995; Hein et al., 1991
; Ilett et al., 1991
; Kirlin et al., 1991
; Land et al., 1994
). Our study demonstrates that NAT1 and NAT2 mRNA was present in the stratified squamous epithelial component of the esophagus, particularly in the proliferative cells lying above the lamina propria. Interestingly, the zone 1 hepatocytes surrounding the portal tracts are also considered to be proliferative in nature and this may indicate an as yet unidentified role of NAT isozymes in cellular proliferation. Few studies have indicated the presence of NAT in esophageal tissue despite it being the entrance to the gastrointestinal tract and an early contact point for dietary carcinogens. In fact, there is only limited data on the presence and localization of xenobiotic metabolizing enzymes within esophageal tissue. In one study, CYP1A, epoxide hydrolase and glutathione S-transferase, but not CYP3A and CYP2C, were identified in the stratified squamous epithelium of human esophagus (Murray et al., 1994
). It should be noted, however, that the authors reported a low frequency of protein expression for these drug-metabolizing enzymes, with not all esophageal samples being immunopositive. In contrast, another laboratory reported the presence of CYP3A4 and CYP3A5 mRNA and the localization of CYP3A protein to the squamous epithelium of the esophagus (Kolars et al., 1994
). The evaluation of NAT activity in human gastrointestinal tissues has been primarily concerned with the colon, due to the suggestion that rapid acetylators may possess a higher incidence of colon cancer (Ilett et al., 1987
). Our work has indicated the presence of NAT1 and NAT2 mRNA in small intestine and colon. In addition to the presence of NAT1 and NAT2 mRNA expression in the surface epithelial cells of both the small intestine and colon, NAT1 and NAT2 expression was also detected in the epithelial cells of the crypts of Lieberkuhn. These cells are proliferative in nature and are responsible for the replenishment of the surface epithelial cells of the villi. In the rat, NAT mRNA has been shown to be predominantly localized to the basal areas of gastric glands in glandular stomach and the differentiated surface epithelial cells of the small intestine and colon (Debiec-Rychter et al., 1996
). Similarly, expression of murine NAT protein is predominant in the tips of the small intestine villus (Stanley et al., 1997
).
Many studies have documented the presence of phase-I enzymes, CYP3A4 and CYP4B1, and the flavoprotein NADPH-cytochrome P450 reductase in the human gastrointestinal tract (Hall et al., 1989; Kolars et al., 1994
; McKinnon et al., 1994
, 1995
; Murray et al., 1988
). CYP3A4 mRNA was observed throughout the tract and was localized to mature surface epithelial cells whereas CYP4B1 mRNA expression was low and restricted to the surface epithelial cells of the colon (McKinnon et al., 1994
, 1995
). CYP3A and NADPH-cytochrome P450 reductase proteins have been identified in mature epithelial cells of a range of human gastrointestinal tissues including small intestine, colon and stomach (Hall et al., 1989
; Kolars et al., 1994
; Murray et al., 1988
). In contrast, using a range of techniques, we have been unable to demonstrate the presence of CYP1A expression in the human gastrointestinal tract (McKinnon et al., 1992
). Given that the majority of food-derived chemicals require metabolism to exert their mutagenic/carcinogenic effect, this observation would suggest that N-hydroxylation of heterocyclic amines occurs in the liver, and the metabolite is then transported to the gastrointestinal tract where it undergoes further activation by the phase-II enzymes. The hydroxylamine of heterocyclic amines may undergo acetylation and/or sulfonation to yield highly reactive acetoxy or sulfoxy derivatives. Clearly, the current study illustrates that NAT transcripts are expressed in a range of gastrointestinal tissues, and indeed, preliminary studies in our laboratory have indicated the additional presence of aryl sulfotransferases in stomach, small intestine, and colon (Windmill et al., 1997
). Other drug-metabolizing enzymes such as glutathione S-transferase and UDP-glucuronosyl-transferase have also been identified throughout surface epithelial cells of the mucosa within the human gastrointestinal tract (Peters et al., 1987
; Terrier et al., 1990
).
In humans, detection of NAT expression and activity in urinary tissues has focused on the bladder, due to the suggested predominance of bladder cancer patients bearing the NAT2 slow acetylator genotype (Kloth et al., 1994; Mommsen and Aagaard, 1986
). N-acetylation is generally considered a detoxification step, since it competes for the amine with the activating, CYP1A2-dependent N-hydroxylation pathway. Individuals producing large quantities of N-hydroxyarylamines are potentially at risk of developing bladder cancer, since NAT is capable of converting these metabolites to unstable acetoxy esters (Frederickson et al., 1992
). The present study demonstrates the presence of both NAT1 and NAT2 mRNA in the urothelium, particularly in the bladder. This is in agreement with human functional and localization studies that have indicated the presence of NAT in urothelium and bladder cell lines (Coroneos and Sim, 1991
; Pink et al., 1992
; Stanley et al., 1996
). Although a recent immunohistochemical study could detect only NAT1 and not NAT2 in bladder epithelium, the authors suggested that their antibody was not of high enough affinity to detect any low levels of NAT2 that could be present (Stanley et al., 1996
). NAT mRNA localization has also been demonstrated in rat bladder epithelium and distal tubules of the rat kidney (Debiec-Rychter et al., 1996
). Transitional epithelium of the murine bladder and the epithelium lining proximal convoluted tubules both demonstrated the presence of NAT protein, suggesting that NAT could metabolize carcinogens present in the urine (Stanley et al., 1997
). Activity assays using renal cytosols from a range of animals have demonstrated NAT activity, including the capacity to activate mutagenic heterocyclic amines (Hearse and Weber, 1973
; Reeves et al., 1991
). In contrast, we were unable to illustrate conclusively the presence of NAT1 or NAT2 mRNA in human kidney. As well as NAT, human urinary tissues express NADPH-cytochrome P450 reductase, CYP3A and glutathione S-transferase (Hall et al., 1989
; Murray et al., 1988
; Singh et al., 1991
; Terrier et al., 1990
).
The presence of NAT2 mRNA in the epithelial cells lining respiratory bronchioles, albeit at low levels, suggests that the enzyme may be important in metabolizing inhaled pollutants. In contrast to these results, NAT1 enzyme activity, but not NAT2, has been detected in laryngeal mucosal tissue from smokers and non-smokers (Stern et al., 1993) and in human lung cytosols (D. M. Grant, unpublished observations). Localization of NAT mRNA to the epithelial lining of rat and mouse bronchi supports our observations in humans; in the rat NAT1 was more predominant than NAT2 (Debiec-Rychter et al., 1996
; Stanley et al., 1997
). Several carcinogenic arylamines, such as 4-aminobiphenyl, ß-naphthylamine and 2-amino-3-methylimidazo[4,5-f]quinoline have been detected in cigarette smoke, leading to the observation that smokers have a higher risk of bladder cancer (Brockmöller et al., 1996
; Talaska et al., 1991
). In contrast to bladder cancer, where slow acetylators appear to be over-represented, carriers of the fast acetylator NAT2*4/*4 genotype may be at greater risk of lung cancer (Cascorbi et al., 1996
). Human bronchial epithelial cells play an important role in the metabolism of inhaled foreign compounds and several studies have indicated the presence of drug-metabolizing enzymes in the lung, including CYP1A1, CYP1A2, CYP1B1, CYP2B7, CYP2E1, CYP3A, CYP4B1, NADPH cytochrome P450 reductase, aryl sulfotransferase, and glutathione S-transferase (Hall et al., 1989
; Kivistö et al., 1995
; McKinnon et al., 1994
; Toussaint et al., 1993
; Willey et al., 1996
).
The ability of a particular arylamine to be activated to a carcinogenic end-product is likely to be strongly dependent upon the relative tissue levels of NAT1, NAT2 and CYP1A2, as well as of other enzymes capable of detoxifying or activating this class of chemical agent. Many of these enzymes are subject to environmental and genetic controls which, in turn, produce interindividual variations in enzyme activity (Grant et al., 1991). In the present study, we have demonstrated the localization of NAT1 and NAT2 mRNA in liver and in a range of extrahepatic tissues, notably the bladder and intestinal tissues. An interesting finding of this study is it demonstrates that NAT2 mRNA expression has a wide tissue distribution similar to NAT1. The presence of NAT in extrahepatic tissues suggests that the N-hydroxylated metabolite might be transported from the liver, where CYP1A2 is expressed, to its target tissue where NAT is capable of activating it to a reactive electrophile. Epidemiological studies have suggested roles for NAT1 and NAT2 in colon, bladder, and lung cancers (Bell et al., 1995
; Brockmöller et al., 1996
; Cascorbi et al., 1996
; Ilett et al., 1987
), and thus an understanding of NAT expression and distribution in human tissues is of considerable importance. In addition, the determination of profiles of other enzymes (e.g., sulfotransferases) involved in carcinogen bioactivation and detoxication will enhance our understanding of any possible role/s they may play in producing or protecting against site-specific carcinogenesis. A logical progression from the current study would be to examine the localization and expression of NAT protein using immunocytochemistry and metabolic activities. Clearly more work is needed to determine the influence that NAT genetic variations may have on levels of expression of mRNA and protein within human tissues, and to assess what role allelic variation may play in interindividual toxic responses to aromatic amines and various disease states.
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NOTES |
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2 To whom correspondence should be addressed. Fax: +61-7-3365-1613. E-mail: m.mcmanus{at}mailbox.uq.edu.au.
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REFERENCES |
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Blum, M., Grant, D. M., McBride, W., Heim, M., and Meyer, U. A. (1990). Human arylamine N-acetyltransferase genes: isolation, chromosomal localization, and functional expression. DNA Cell Biol. 9, 193203.[ISI][Medline]
Brockmöller, J., Cascorbi, I., Kerb, R., and Roots, I. (1996). Combined analysis of inherited polymorphisms in arylamine N-acetyltransferase 2, glutathione S-transferases M1 and T1, microsomal epoxide hydrolase, and cytochrome P450 enzymes as modulators of bladder cancer risk. Cancer Res. 56, 39153925.[Abstract]
Cascorbi, I., Brockmöller, J., Mrozikiewicz, P. M., Bauer, S., Loddenkemper, R., and Roots, I. (1996). Homozygous rapid arylamine N-acetyltransferase (NAT2) genotype as a susceptibility factor for lung cancer. Cancer Res. 56, 39613966.[Abstract]
Coroneos, E., and Sim, E. (1991). N-acetyltransferase in human urothelium and bladder cell lines. Biochem. Soc. Trans. 19, 129S.[Medline]
Cribb, A. E., Grant, D. M., Miller, M. A., and Spielberg, S. P. (1991). Expression of monomorphic arylamine N-acetyltransferase (NAT1) in human leukocytes. J. Pharmacol. Exp. Ther. 259, 12411246.[Abstract]
Debiec-Rychter, M., Land, S. J., and King, C. M. (1996). Histological localization of messenger RNAs for rat acetyltransferases that acetylate serotonin and genotoxic arylamines. Cancer Res. 56, 15171525.[Abstract]
Deguchi, T., Mashimo, M., and Suzuki, T. (1990). Correlation between acetylator phenotypes and genotypes of polymorphic arylamine N-acetyltransferase in human liver. J. Biol. Chem. 265, 1275712760.
Frederickson, S. M., Hatcher, J. F., Reznikoff, C. A., and Swaminathan, S. (1992). Acetyl transferase-mediated metabolic activation of N-hydroxy-4-aminobiphenyl by human uroepithelial cells. Carcinogenesis 13, 955961.[Abstract]
Grant, D. M. (1993). Molecular genetics of the N-acetyltransferases. Pharmacogenetics 3, 4550.[ISI][Medline]
Grant, D. M., Blum, M., Beer, M., and Meyer, U. A. (1991). Monomorphic and polymorphic human arylamine N-acetyltransferases: a comparison of liver isozymes and expressed products of two cloned genes. Mol. Pharmacol. 39, 184191.[Abstract]
Grant, D. M., Hughes, N. C., Janezic, S. A., Goodfellow, G. H., Chen, H. J., Gaedigk, A., Yu, V. L., and Grewal, R. (1997). Human acetyltransferase polymorphisms. Mutat. Res. 376, 6170.[ISI][Medline]
Hall, P. de la M., Stupans, I., Burgess, W., Birkett, D. J., and McManus, M. E. (1989). Immunohistochemical localization of NADPH-cytochrome P450 reductase in human tissues. Carcinogenesis 10, 521530.[Abstract]
Hearse, D. J., and Weber, W. W. (1973). Multiple N-acetyltransferases and drug metabolism. Tissue distribution, characterization and significance of mammalian N-acetyltransferase. Biochem. J. 132, 519526.[ISI][Medline]
Hein, D. W. (1988). Acetylator genotype and arylamine-induced carcinogenesis. Biochim. Biophys. Acta. 948, 3766.[ISI][Medline]
Hein, D. W., Doll, M. A., Fretland, A. J., Gray, K., Deitz, A. C., Feng, Y., Jiang, W., Rustan, T. D., Satran, S. L., and Wilkie, T. R. (1997). Rodent models of the human acetylation polymorphism: Comparisons of recombinant acetyltransferases. Mutat. Res. 376, 101106.[ISI][Medline]
Hein, D. W., Rustan, T. D., Bucher, K. D., and Miller, L. S. (1991). Polymorphic and monomorphic expression of arylamine carcinogen N-acetyltransferase isozymes in tumor target organ cytosols of Syrian hamsters congenic at the polymorphic acetyltransferase locus. J. Pharmacol. Exp. Ther. 259, 699704.[Abstract]
Hickman, D., and Sim, E. (1991). N-acetyltransferase polymorphism. Comparison of phenotype and genotype in humans. Biochem. Pharmacol. 42, 10071014.[ISI][Medline]
Ilett, K. F., David, B. M., Detchon, P., Castledon, W. M., and Kwa, R. (1987). Acetylation phenotype in colorectal carcinoma. Cancer Res. 47, 14661469.[Abstract]
Ilett, K. F., Reeves, P. T., Minchin, R. F., Kinnear, B. F., Watson, H. F., and Kadlubar, F. F. (1991). Distribution of acetyltransferase activities in the intestines of rapid and slow acetylator rabbits. Carcinogenesis 12, 14651469.[Abstract]
Kirlin, W. G., Ogolla, F., Andrews, A. F., Trinidad, A., Ferguson, R. J., Yerokun, T., Mpezo, M., and Hein, D.W. (1991). Acetylator genotype-dependent expression of arylamine N-acetyltransferase in human colon cytosol from non-cancer and colorectal cancer patients. Cancer Res. 51, 549555.[Abstract]
Kivistö, K. T., Fritz, P., Linder, A., Friedel, G., Beaune, P., and Kroemer, H. K. (1995). Immunohistochemical localization of cytochrome P450 3A in human pulmonary carcinomas and normal bronchial tissue. Histochemistry 103, 2529.[ISI][Medline]
Kloth, M. T., Gee, R. L., Messing, E. M., and Swaminathan, S. (1994). Expression of N-acetyltransferase (NAT) in cultured human uroepithelial cells. Carcinogenesis 15, 27812787.[Abstract]
Kolars, J. C., Lown, K. S., Schmiedlin-Ren, P., Ghosh, M., Fang, C., Wrighton, S. A., Merion, R. M., and Watkins, P. B. (1994). CYP3A gene expression in human gut epithelium. Pharmacogenetics 4, 247259.[ISI][Medline]
Land, S. J., Jones, R. F., and King, C. M. (1994). Biochemical and genetic analysis of two acetyltransferases from hamster tissues that can metabolize aromatic amine derivatives. Carcinogenesis 15, 15851595.[Abstract]
McKinnon, R A., Burgess, W. M., Gonzalez, F. J., Gasser, R., and McManus, M. E. (1994). Species-specific expression of CYP4B1 in rabbit and human gastrointestinal tissues. Pharmacogenetics 4, 260270.[ISI][Medline]
McKinnon, R. A., Burgess, W. M., Hall, P. de la M., Abdul-Aziz, Z., and McManus, M. E. (1992). Metabolism of food-derived heterocyclic amines in human and rabbit tissues by P4503A proteins in the presence of flavonoids. Cancer Res. 52, 2108s2113s.[Abstract]
McKinnon, R. A., Burgess, W. M., Hall, P. de la M., Roberts-Thomson, S. J., Gonzalez, F. J., and McManus, M. E. (1995). Characterisation of CYP3A gene subfamily expression in human gastrointestinal tissues. Gut 36, 259267.[Abstract]
McKinnon, R. A., Hall, P. de la M., Quattrochi, L. C., Tukey, R. H., and McManus, M. E. (1991). Localization of CYP1A1 and CYP1A2 messenger RNA in normal human liver and in hepatocellular carcinoma by in situ hybridization. Hepatology 14, 848856.[ISI][Medline]
McManus, M. E., Burgess, W. M., Veronese, M. E., Huggett, A., Quattrochi, L. C., and Tukey, R. H. (1990). Metabolism of 2-acetylaminofluorene and benzo[]pyrene and activation of food-derived heterocyclic amine mutagens by human cytochromes P-450.Cancer Res. 50, 33673376.[Abstract]
Minchin, R. F., Reeves, P. T., Teitel, C. H., McManus, M. E., Mojarrabi, B., Ilett, K. F., and Kadlubar, F. F. (1992). N- and O-acetylation of aromatic and heterocyclic amine carcinogens by human monomorphic and polymorphic acetyltransferases expressed in COS-1 cells. Biochem. Biophys. Res. Commun. 185, 839844.[ISI][Medline]
Mommsen, S., and Aagaard, J. (1986). Susceptibility in urinary bladder cancer: acetyltransferase phenotypes and related risk factors. Cancer Lett. 32, 199205.[ISI][Medline]
Murray, G. I., Barnes, T. S., Sewell, H. F., Ewen, S. W. B., Melvin, W. T., and Burke, M. D. (1988). The immunocytochemical localisation and distribution of cytochrome P-450 in normal human hepatic and extrahepatic tissues with a monoclonal antibody to human cytochrome P-450. Br. J. Clin. Pharmacol. 25, 465475.[ISI][Medline]
Murray, G. I., Shaw, D., Weaver, R. J., McKay, J. A., Ewen, S. W. B., Melvin, W. T., and Burke, M. D. (1994). Cytochrome P450 expression in oesophageal cancer. Gut 35, 599603.[Abstract]
Peters, W. H., Allebes, W. A., Jansen, P. L., Poels, L. G., and Capel, P. J. (1987). Characterization and tissue specificity of a monoclonal antibody against human uridine 5'-diphosphate-glucuronosyltransferase. Gastroenterology 93, 162169.[ISI][Medline]
Pink, J. C., Messing, E. M., Reznikoff, C. A., Bryan, G. T., and Swaminathan, S. (1992). Correlation between N-acetyltransferase activities in uroepithelia and in vivo acetylator phenotype. Drug Metab. Dispos. 20, 559565.[Abstract]
Reeves, P. T., Kinnear, B. F., Minchin, R. F., and Ilett, K.F. (1991). Immunological evidence for N-acetyltransferase isozymes in the rabbit. Mol. Pharmacol. 39, 4248.[Abstract]
Sabbagh, N., Delaporte, E., Marez, D., Lo-Guidice, J-M., Piette, F., and Broly, F. (1997). NAT2 genotyping and efficacy of sulfasalazine in patients with chronic discoid lupus erythematosus. Pharmacogenetics 7, 131135.[ISI][Medline]
Singh, S. V., Roberts, B., Gudi, V. A., Ruiz, P. and Awasthi, Y. C. (1991). Immunohistochemical localization, purification, and characterization of human urinary bladder and glutathione S-transferases. Biochim. Biophys. Acta 1074, 363370.[ISI][Medline]
Stanley, L. A., Coroneos, E., Cuff, R., Hickman, D., Ward, A., and Sim, E. (1996). Immunochemical detection of arylamine N-acetyltransferase in normal and neoplastic bladder. J. Histochem. Cytochem. 44, 10591067.
Stanley, L. A., Mills, I. G., and Sim, E. (1997). Localization of polymorphic N-acetyltransferase (NAT2) in tissues of inbred mice. Pharmacogenetics 7, 121130.[ISI][Medline]
Stern, S. J., Degawa, M., Martin, M. V., Guengerich, F. P., Kaderlik, R. K., Ilett, K. F., Breau, R., McGhee, M., Montague, D., Lyn-Cook, B., and Kadlubar, F. F. (1993). Metabolic activation, DNA adducts, and H-ras mutations in human neoplastic and non-neoplastic laryngeal tissue. J. Cell. Biochem. 17(Suppl. F), 129137.
Talaska, G., al-Juburi, A. Z., and Kadlubar, F. F. (1991). Smoking related carcinogen-DNA adducts in biopsy samples of human urinary bladder: identification of N-(deoxyguanosin-8-yl)-4-aminobiphenyl as a major adduct. Proc. Natl, Acad. Sci. U S A. 88, 53505354.
Terrier, P., Townsend, A. J., Coindre, J. M., Triche, T. J., and Cowan, K. H. (1990). An immunohistochemical study of pi class glutathione S-transferase expression in normal human tissue. Am. J. Pathol. 137, 845853.[Abstract]
Toussaint, C., Albin, N., Massaad, L., Grunenwald, D., Parise, O., Jr., Morizet, J., Gouyette, A., and Chabot, G. G. (1993). Main drug- and carcinogen-metabolizing enzyme systems in human non-small cell lung cancer and peritumoral tissues. Cancer Res. 53, 46084612.[Abstract]
Weber, W. W., and Vatsis, K. P. (1995). Human N-acetyltransferases: genetic polymorphism and metabolic profiles of the major isoforms. In Advances in Drug Metabolism in Man (G. M. Pacifici and G. N. Fracchia, Eds.), pp. 351405. European Commission, Luxembourg.
Willey, J. C., Coy, E., Brolly, C., Utell, M. J., Frampton, M. W., Hammersley, J., Thilly, W. G., Olson, D., and Cairns, K. (1996). Xenobiotic metabolism enzyme gene expression in human bronchial epithelial and alveolar macrophage cells. Am. J. Respir. Cell Mol. Biol. 14, 262271.[Abstract]
Windmill, K. F., McKinnon, R. A., Zhu, X., Gaedigk, A., Grant, D. M., and McManus, M. E. (1997). The role of xenobiotic metabolizing enzymes in arylamine toxicity and carcinogenesis: functional and localization studies. Mutat. Res. 376, 153160.[ISI][Medline]