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In the kidney, cytochrome P450 (CYP) is involved in arachidonic acid metabolism and the maintenance of homeostasis, but only scarce information is available as to how CYP expression is altered in rodent renal carcinomas (RCs). TSC2 gene mutant (Eker) rat RCs are an example of a Mendelian dominantly inherited predisposition to a specific cancer in an experimental animal. In the present study, the expression of CYP in Eker RCs was studied. In the normal kidney, CYP 1A1 and 4A1 mRNAs were expressed, but this expression was suppressed in spontaneously-induced Eker RCs and in cell line Lk9dL and Lk9dR. In Lk9dL and Lk9dR, Ah receptor nuclear translocator and haemoxygenase-1 mRNAs were expressed, but this expression was inconsistent in spontaneously-induced Eker RCs. The present results showed the suppression of CYP 1A1 and 4A1 mRNA expression in spontaneously-induced Eker RCs and this suppression indicates altered metabolic conditions in Eker RCs. 相似文献
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Hs578T human breast cancer cells are an oestrogen receptor (ER)-negative cell line. Treatment of these cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in formation of a 6.9 S nuclear aryl hydrocarbon (Ah) receptor complex, which bound to a [32P]dioxin-responsive element in a gel electrophoretic mobility shift assay. However, TCDD does not induce CYP1A1 gene expression or chloramphenicol acetyl transferase (CAT) activity in cells transiently transfected with pRNH11c or pMCAT5.12, which are Ah-responsive plasmids derived from the 5''-flanking region of the human and murine CYP1A1 genes respectively. Restoration of Ah responsiveness was investigated by co-transfecting Hs578T cells with pRNH11c or pMCAT5.12 and plasmids that express the ER (hER), Ah receptor (AhR) and AhR nuclear translocator (Arnt) proteins. ER expression resulted in significantly increased basal CAT activity; however, TCDD did not induce CAT activity in the transiently transfected cells. Expression of the AhR or Arnt proteins did not alter basal or inducible CAT activity. Expression of N- or C-terminal truncated ER in Hs578T resulted in differential regulation of Ah responsiveness. In Hs578T cells transiently expressing the ER, which contains C-terminal deletions (amino acids 282-595), basal CAT activity was also increased; however, Ah responsiveness was not restored. In contrast, transient expression of N-terminal-deleted (amino acids 1-178) ER resulted in a marked decrease in basal CAT activity but a restoration of Ah responsiveness. These results suggest that basal and inducible CAT activity in Hs578T cells transiently transfected with pRNH11c is modulated differentially by ER domains that are present in the N- and C-terminal regions of the ER. 相似文献
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Induction of CYP1A1 gene expression in H4-II-E rat hepatoma cells by benzo[e]pyrene. 总被引:1,自引:0,他引:1
In the rat, expression of the CYP1A1 gene is closely associated with arylhydrocarbon hydroxylase (AHH) enzyme activity. AHH is an inducile enzyme activity known to play an important role in the bioactivation of polycyclic aromatic hydrocarbons (PAHs) to mutagenic and carcinogenic metabolites. PAH-induced expression of the CYP1A1 gene appears to be regulated by several trans-acting factors, including the Ah receptor and the 4S PAH-binding protein. In this study, we used the PAH isomers benzo[a]pyrene (BaP) and benzo[e]pyrene (BeP) to further evaluate the role of the 4S PAH-binding protein in induction of the CYP1A1 gene in H4-II-E rat hepatoma cells. Although BaP is believed to bind to both the Ah receptor and the 4S protein, BeP has been reported to bind exclusively to the 4S protein. The results of the study presented here indicate that BaP and BeP induce the expression of the CYP1A1 gene, as measured by ethoxyresorufin O-deethylase (EROD) activity, in a concentration-dependent manner. However, BaP is about 25 times as potent as BeP in inducing EROD activity in these cells. Slot-blot analysis of total RNA isolated from these cells indicated that BeP, BaP, and 3-methylcholanthrene increased the level of CYP1A1 mRNA expression. Sucrose-gradient analysis of BeP binding activity indicated that BeP bound with high affinity to the 4S PAH-binding protein, but not to the Ah receptor. These results suggest that the 4S protein may play a role in the PAH-induced expression of the CYP1A1 gene in rat H4-II-E cells. 相似文献
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Differential expression of CYP1A1 and CYP1B1 in human breast epithelial cells and breast tumor cells 总被引:12,自引:9,他引:12
Spink DC; Spink BC; Cao JQ; DePasquale JA; Pentecost BT; Fasco MJ; Li Y; Sutter TR 《Carcinogenesis》1998,19(2):291-298
Human cytochromes P450 1A1 (CYP1A1) and P450 1B1 (CYP1B1) catalyze the
metabolic activation of a number of procarcinogens and the hydroxylation of
17beta-estradiol (E2) at the C-2 and C-4 positions, respectively. The
aromatic hydrocarbon receptor (AhR) agonist 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD) has a marked effect on estrogen
metabolism in MCF-7 breast-tumor cells by induction of these two enzymes.
To investigate whether induction of CYP1A1 and CYP1B1 by AhR agonists and
the associated increase in E2 metabolism are common to all breast
epithelial cells and breast-tumor cells, we determined the effects of TCDD
on E2 metabolism, and CYP1A1 and CYP1B1 mRNA levels in a series of
non-tumor-derived breast epithelial (184A1 and MCF-10A) and breast-tumor
(MCF-7, T-47D, ZR-75-1, BT-20, MDA-MB-157, MDA-MB-231 and MDA-MB-436) cell
lines. In 184A1 cells, which did not express detectable estrogen receptor
(ER) alpha mRNA, CYP1A1 mRNA and activity were induced by TCDD, and
enhanced E2 metabolism in TCDD-treated cells was predominantly E2
2-hydroxylation. In MCF-10A, MCF-7, T-47D, ZR-75-1 and BT-20 cells, which
expressed varying levels of ER alpha mRNA, both CYP1A1 and CYP1B1 mRNA
levels and rates of both E2 2- and 4- hydroxylation were highly elevated
following exposure to TCDD. In MDA- MB-157, MDA-MB-231 and MDA-MB-436
cells, which did not express detectable ER alpha mRNA and generally
displayed fibroblastic or mesenchymal rather than epithelial morphology,
CYP1B1 induction was favored, and the rate of E2 4-hydroxylation exceeded
that of 2- hydroxylation in TCDD-treated cells. These results show that
breast epithelial cells and tumor cells vary widely with regard to AhR-
mediated CYP1A1 and CYP1B1 induction, suggesting that factors in addition
to the AhR regulate CYP1A1 and CYP1B1 gene expression. In these cell lines,
significant CYP1A1 inducibility was restricted to cultures displaying
epithelial morphology, whereas CYP1B1 inducibility was observed in cells of
both epithelial and mesenchymal morphology.
相似文献
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Hideaki Kikuchi Masahiro Usuda Ikuko Sagami Shuntaro Ikawa Minro Watanabe 《Cancer science》1994,85(7):710-717
We have isolated new benzo[α]pyrene-resistant clones, cl-21 and cl-32, of the mouse hepatoma line, Hepa-1. CYP1A1-dependent aryl hydrocarbon hydroxylase activity is not inducible by 2,3,7,8-tetrachlorodibenzo- p -dioxin or 3-methylcholanthrene in these two cell lines. However, mRNA of CYP1A1 is inducible in cl-21 and cl-32 cells, as in the wild-type cells, in spite of an undetectable level of cytosolic Ah receptor. The cl-21 cDNA of Cypla-1 was found to have a single mutation leading to an amino acid substitution from Leu (118) to Arg (118). However, the CYP1A1 protein band was not detected on Western immunoblots. The cDNA of cl-32 was found to have a single mutation leading to an amino acid change from Arg (359) to Trp (359). The presence of the mature protein in cl-32 was confirmed by Western blot analysis. Somatic cell hybridization experiments demonstrated that the phenotype of cl-21 and cl-32 is recessive and that these clones belong to the same complementation group. These data suggest that there may be a non-Ah receptor-mediated mechanism of CYP1A1 induction. 相似文献
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The expression of CYP1B1 in human mammary fibroblasts (HMFs) was
characterized as a potential modulator of their individual function as well
as effects on adjacent mammary epithelia. We have used these
characteristics to explore the diversity of fibroblast cells isolated from
reduction mammoplasty patients and from different breast locations in
breast cancer patients (tumors, peripheral to tumor and skin). These
parameters have also been used to examine differences between two donors.
The results have shown that while none of these HMFs expressed a detectable
CYP1A1 protein basally or in response to TCDD, they all expressed CYP1B1
constitutively at similar levels (0.5-0.9 pmol/mg microsomal proteins) and
they were induced by TCDD (up to 5-fold) consistent with mediation by the
Ah receptor (AhR). DMBA metabolism by HMFs exhibited high proportions of
5,6-, 10,11- and 3,4-dihydrodiols, a profile that is typical of human
CYP1B1 regioselectivity. RT-PCR followed by Southern blot analyses
demonstrated that CYP1B1 mRNA expression in HMFs parallels levels of
respective microsomal proteins. The AhR is expressed in these HMFs as two
cytosolic forms (approximately 106 and 104 kDa) and a substantial
proportion of the 104 kDa form was localized to the nucleus even prior to
TCDD treatment. In all HMFs isolated directly from collagenase digested
breast tissues the AhR is expressed at levels 10-fold lower than in breast
epithelial cells. However, HMFs that were isolated after serial passaging
of mammary epithelial cultures had shown much higher levels of the AhR
expression and more dramatic TCDD-induced down-regulation (>80% in 24 h)
associated with more efficient nuclear translocation. These differences
suggested the presence of two functionally distinct subtypes of HMFs:
interstitial stromal fibroblasts that are readily released by collagenase
digestion of breast tissues, and lobular stromal fibroblasts which are more
tightly associated with the breast epithelia.
相似文献
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Sirkku T. Saarikoski Kirsti Husgafvel-Pursiainen Ari Hirvonen Harri Vainio Frank J. Gonzalez Sisko Anttila 《International journal of cancer. Journal international du cancer》1998,77(1):33-39
Cytochrome P4501A1 (CYP1A1) is involved in the bioactivation of polycyclic aromatic hydrocarbons into their reactive epoxide metabolites. CYP1A1 is considered to be important with regard to individual susceptibility to lung cancer since phenotypic and genotypic polymorphisms of CYP1A1 have been associated with an increased risk of lung cancer in a number of studies. We examined here the expression and localization of CYP1A1 mRNA in human lung tissue using in situhybridization with a CYP1A1-specific RNA probe. A centrilobular expression of CYP1A1 mRNA was observed in the peripheral lung. The expression was intense in bronchiolar epithelium of peripheral lung, especially in terminal cuboidal epithelium. Type II alveolar epithelial cells were also intensely labelled. Type I alveolar epithelial cells and vascular epithelium exhibited binding but the hybridization signals were less intense. Our results are in good agreement with our previous work on immunohistochemical localization of CYP1A protein, in which we used the 1-7-1 MAb that recognizes both CYP1A1 and CYP1A2. In serial sections analyzed with in situhybridization and immunohistochemistry, a similar distribution of CYP1A1 mRNA and CYP1A protein was observed. CYP1A1 mRNA is thus expressed in human lungs and the expression is particularly intense in the cell types involved in the development of peripheral lung cancers. Int. J. Cancer 77:33–39, 1998.© 1998 Wiley-Liss, Inc. 相似文献
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T L McLemore S Adelberg M C Liu N A McMahon S J Yu W C Hubbard M Czerwinski T G Wood R Storeng R A Lubet 《Journal of the National Cancer Institute》1990,82(16):1333-1339
The major polycyclic aromatic hydrocarbon inducible-cytochrome P4501A1 gene (CYP1A1) is presumed to be important in pulmonary carcinogenesis and toxicology because its product, the cytochrome P4501A1-dependent (CYP1A1-dependent) monooxygenase, transforms selected xenobiotics (including polycyclic aromatic hydrocarbon procarcinogens in cigarette smoke) to potent carcinogenic metabolites. CYP1A1 messenger RNA (mRNA) expression has not, however, been previously demonstrated in human pulmonary tissue. This report defines CYP1A1 gene expression in normal lung tissue and primary pulmonary carcinoma tissue obtained at thoracotomy from 56 patients with lung cancer. When Northern blot hybridization analyses were performed, 17 of 19 (89%) and zero of five (0%) samples of normal lung tissue from active cigarette smokers and nonsmokers, respectively, expressed the normal 2.8-kilobase CYP1A1 mRNA. In addition, a time-dependent decrease in expression of the CYP1A1 gene was noted in normal lung tissue from individuals who were former smokers, with a decrease in expression occurring as early as 2 weeks following cessation of cigarette smoking. Expression became undetectable in all patients who had stopped smoking more than 6 weeks prior to study. When CYP1A1 gene expression was evaluated in lung cancers, mRNA levels were detectable in one of four (25%) tumors from nonsmokers; two of 24 (8%) tumors from former smokers; and seven of 15 (47%) tumors from cigarette smokers. In addition, an approximately 10-kilobase CYP1A1 RNA species, which was not detectable in normal lung tissue, was observed in five of ten (50%) of the lung cancers that expressed the CYP1A1 gene.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Godoy W Albano RM Moraes EG Pinho PR Nunes RA Saito EH Higa C Filho IM Kruel CD Schirmer CC Gurski R Lang MA Pinto LF 《Carcinogenesis》2002,23(4):611-616
Oesophageal cancer is one of the most common and lethal malignancies in the world. Despite many efforts, treatment is still ineffective for most cases; thus, the development of preventive strategies is crucial for decreasing the burden presented by this disease. Environmental factors, particularly nitrosamines, are thought to be involved in the genesis of oesophageal tumours, and knowledge about the expression of enzymes capable of activating pre-carcinogens in human oesophagus is very important for the development of preventive measures. We analysed the expression of CYP1A1, CYP1A2, CYP2A6/2A7, CYP2E1 and CYP3A4 mRNA in oesophageal mucosa of 50 patients by semi-quantitative RT-PCR. In five patients, who suffered from squamous cell carcinoma, we measured Nnitrosodimethylamine and N-nitrosodiethylamine metabolism in normal and tumorous tissue. CYP2A6/2A7 mRNA was expressed in 61% and CYP2E1 mRNA in 96% of the patients, but in the latter a lower degree of inter-individual variation was observed. These enzymes were expressed either in the distal or middle portions of the oesophagus of 90% of the patients. CYP1A1, CYP1A2 and CYP3A4 mRNA expression was not detected in any portion of the oesophagus. Oesophageal microsomes activated N-nitrosodimethylamine with a low degree of inter-individual variation and microsomes prepared from the tumour of a patient who strongly expressed CYP2A6/2A7 mRNA activated N-nitrosodiethylamine. We conclude that the human oesophagus expresses CYP2A6/2A7 and CYP2E1 and can activate nitrosamines. Notably, the expression of these enzymes is preferentially localized to the most common sites where tumours arise. 相似文献
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目的 :研究CYP1A1mRNA在大鼠脑内的分布以及溴氰菊酯对其影响。方法 :采用RT -PCR及cDNAdotblot方法检测大鼠不同脑区CYP1A1mRNA的表达。结果 :大鼠脑区CYP1A1mRNA分布不一致 ,在所检测的脑区中 ,下丘脑最丰富 ,其次是皮层、小脑 ;在溴氰菊酯 1/ 10LD50 (12 .5mg .kg-1.d-1)腹腔注射连续 5d的作用下 ,溴氰菊酯对大鼠脑内CYP1A1mRNA有明显的抑制作用 ,并以皮层和下丘脑为甚。结论 :CYP1A1mRNA在大鼠脑内的分布不一致 ,溴氰菊酯抑制脑内CPY1A1mRNA的表达 相似文献
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Detection of CYP1A1 protein in human liver and induction by TCDD in precision-cut liver slices incubated in dynamic organ culture 总被引:7,自引:1,他引:7
Cytochrome P4501A1 (CYP1A1) has been implicated in the conversion of
numerous polycyclic aromatic hydrocarbons into electrophilic species
capable of binding covalently to DNA and has therefore been postulated to
be involved in the initiation of carcinogenesis. The expression of CYP1A1
protein appears not to be constitutive, but is readily inducible by aryl
hydrocarbon (Ah) receptor ligands in a majority of tissues of experimental
animals, especially the liver. To date, there is conflicting evidence for
the expression or inducibility of CYP1A1 protein in human liver. In this
present study, we report the detection of CYP1A1 in all 20 human liver
microsomal samples tested by standard western immunoblotting with
chemiluminescent detection using a specific monoclonal antibody (mAb
1-12-3) directed against a marine fish (scup) cytochrome P450E. mAb 1-12-3
has been shown previously to specifically recognize CYP1A1 in mammals. This
system consistently demonstrated a detection sensitivity as low as
0.01-0.025 pmol CYP1A1 per lane. In the samples where CYP1A1 protein levels
were quantitated, CYP1A1 ranged from approximately 0.4 to 5 pmol CYP1A1/mg
microsomal protein. Additionally, the inducibility of CYP1A1 protein was
demonstrated by incubating precision-cut human liver slices in dynamic
organ culture for up to 96 h in the presence of
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The specificity of mAb 1-12-3
was tested using several purified human and rat cytochrome P450s to ensure
that the protein being detected was CYP1A1. mAb 1-12-3 did not cross-react
with human CYP1A2 or CYP3A4 or rat CYP1B1, but did strongly recognize
CYP1A1. However, there was a very weak cross-reactivity of mAb 1-12-3 with
human CYP2E1, approximately 75-fold less compared with CYP1A1. In order to
confirm CYP1A1 as the immunoreactive protein detected in human liver,
microsomal samples were subjected to two-dimensional electrophoresis
involving isoelectric focusing followed by SDS-PAGE and immunoblotting.
Utilizing mAb 1-12-3, the human liver microsomal samples displayed an
immunoblotting profile matching that obtained from a microsomal preparation
from a AHH-1 TK+/- cell line expressing solely human CYP1A1 and differing
from the profile obtained using a polyclonal antibody directed against
CYP2E1 and cells expressing CYP2E1. Furthermore, mAb 1- 12-3 recognized
only one protein of identical mobility on the two- dimensional blots from
human liver microsomes and AHH-1 TK+/- cells expressing CYP1A1, while
displaying no reaction to cells expressing only CYP2E1. In conclusion,
CYP1A1 appears to be expressed in human liver at low levels and is
inducible upon exposure to TCDD.
相似文献
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Kenji Toide Hiroshi Yamazaki Rikako Nagashima Keisuke Itoh Shunsuke Iwano Yoshiki Takahashi Shaw Watanabe Tetsuya Kamataki 《Cancer epidemiology, biomarkers & prevention》2003,12(3):219-222
The expression level of mRNAs for cytochrome P450 (CYP) 1A1 and 1B1 in freshly prepared white cells from 72 subjects exposed to dioxins at waste incinerators was investigated. The amounts of CYP1B1 mRNA ranged from 0.16 to 671 molecules/10(7) molecules of 18S rRNA, whereas the amounts of CYP1A1 mRNA were <6 molecules/10 ng total RNA, indicating that CYP1A1 was not induced to a detectable level by environmentally exposed dioxins. The inducibility of CYP1B1 mRNA in leukocytes, defined as the ratio of CYP1B1 mRNA to the plasma concentration of dioxins, varied among the subjects. It was found that the subjects showed trimodal distribution according to inducibility: 39 (54.2%), 25 (34.7%), and 8 (11.1%) of 72 subjects were judged as poor, intermediate, and high responders to environmental dioxins, respectively. The amounts of CYP1B1 mRNA in leukocytes of the intermediate and high responders were highly correlated with the plasma concentrations of dioxins (P < 0.05 and <0.01). These results suggest that CYP1B1 with polymorphic inducibility by dioxins is involved in aromatic hydrocarbon hydroxylase activities in human lymphocytes. 相似文献