• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.89-89
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• 2003

Exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a variety of biological and toxicology effects, most of which are mediated by aryl hydrocarbon receptor (AhR). The ligand-bound AhR as a heterodimer with AhR nuclear translocator (ARNT) binds to its specific DNA recognition site, the dioxin-responsive element (DRE), and it results in increased transcription of CYP1A1 gene. Retinoic acid (RA) regulates the transcription of various genes for several essential functions through binding to two classes of nuclear receptors, the retinoic acid receptor (RAR) and retinoid X receptor (RXR). Constitutive androstane receptor (CAR) also regulates the transcription of gene. In this study, we have examined how RAR, RXR and CAR regulated CYP1A1 in rainbow trout hepatoma cell (RTH 149) using luciferase reporter gene assay system. We did transient transfection with CYP1A1 luciferase reporter gene and treated with TCDD, all-trans RA, 9-cis RA and phenobarbital. Treatment of all-trans RA, 9-cis RA or phenobarbital decreased the TCDD induced transcription of CYP1Al. When we did transient cotransfection with CYP1A1 luciferase reporter gene and RXR, as increase of RXR concentration, the TCDD induced transcription of CYP1A1 was decreased. Transfection with CAR also decreased the TCDD induced transcription of CYP1A1 in RTH 149 cells.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.375-380
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• 2002

Cytochrome P4501A2 (CYP1A2) is a member of the cytochrome P450 family of isozymes involved in the phase I drug metabolism of vertebrates. CYP1A2 is responsible for the activation of a number of aromatic amines to mutagenic and carcinogenic forms. Thus, the level of CYP1A2, which varies among different populations, may determine an individual's susceptibility to these chemicals. We have previously reported on the importance of a cis element named PRB (protected region B) in the regulation of human Cytochrome P4501A2 (CYP1A2) gene, which appeared to act as a positive regulatory element. Closer examination of the PRB sequence (-2218 to -2187 bp) revealed a putative AP-1 binding site, TGACTAA, at -2212 bp (Chung and Bresnick, 1997). To elucidate the role of AP-1 in CYP1A2 regulation, we transiently overexpressed c-Jun and c-Fos transcription factors in human hepatoma HepG2 cells, and examined their influence on the CYP1A2 promoter activity by reporter gene assays. Cotransfection of the c-Jun and the c-Fos expression vectors increased the induced transactivation by five to six fold from the CYP1A2 promoter constructs. However, deletion of the PRB element did not affect the degree of activation by the c-Jun and the c-Fos. Therefore, it is unlikely that the c-Jun and the c-Fos activate the CYP1A2 promoter through this AP-1 consensus-like sequence in the PRB region.

• 한국환경성돌연변이발암원학회지
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• 제23권1호
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• pp.30-34
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• 2003

Recent industrial society has human widely exposed to PAHs (polynuclear aromatic hydrocarbons) that are comming from the incomplete combustion of organic material as wider spread environmental contaminants. Biological activities of PAHs are not known although PAHs are considered as carcinogens. Our laboratory have been studied the effect of PAHs in the mouse liver hepa 1 cells. In this study, we examined the mouse liver hepa-l cells as a new bioassay system to evaluate bioactivity of PAHs. We have selected 13 PAHs to examine bioassay using cyp1a1-luciferase reporter gene expression system where cyp1a1 1.6 Kb 5flanking region DNA was cloned in front of luciferase reporter gene and this plasmid was transfected into hepa 1 cells transiently. This cells then used for the study to observe the effect of PAHs. We demonstrated that PAHs induced the CYP1A1 promoter and 7-ethoxyresolufin O-deethylase (EROD) activities in a concentration-dependant manner. Some of PAHs showed stronger stimulatory effect on CYP1 gene expression than TCDD. Acenaphthene, anthracene, fluorine, naphthalene, pyrene, phenanthrene, carbazole were weak responders to cyp1a1 promoter activity stimulation and EROD induction in hepa 1 cells and these chemicals seemed to respond less to EROD than cyp1a1 promoter activity. Benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, and dibenzo(a,h)anthracene showed strong response to cyp1a1 promoter activity stimulation and also EROD induction in hepa 1cells. Results of dose response study suggested that four strong responding PAHs, such as benzo(a)anthracene benzo(k)fluoranthene, chrysene, and dibenzo(a, h)anthracene might be mediated through arylhydrocarbon receptor system in hepa1 cells.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.289-294
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• 2012

Gene expressions of cytochrome P4501A (CYP1A), aryl hydrocarbon receptor (AhR) and vitellogenin (Vg) by endocrine disruptors, benzo[${\alpha}$]pyrene (B[a]P) and tributyltin (TBT) were examined in cultured eel hepatocytes which were isolated from eels treated previously with B[a]P (10 mg/kg) or estradiol-$17{\beta}$ (20 mg/kg) in vivo, and the relationship between CYP1A, AhR and Vg genes were studied. When the cultured eel hepatocytes were treated with B[a]P ($10^{-6}-10^{-5}M$) the gene expressions of CYP1A and AhR were enhanced in a concentration-dependent manner. However, when treated with TBT ($10^{-9}-10^{-5}M$) the gene expressions of CYP1A and AhR were suppressed at high concentrations ($10^{-6}-10^{-5}M$), while having no effects at low concentrations ($10^{-9}-10^{-7}M$). Gene expression of Vg was also suppressed by TBT in a concentration-dependent manner in cultured eel hepatocytes which was previously treated in vivo with estradiol-$17{\beta}$.

• Journal of Genetic Medicine
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• 제1권1호
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• pp.27-31
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• 1997

Steroid 21 hydroxylase deficiency is a major cause of congenital adrenal hyperplasia (CAH) and is caused by genetic impairment of the gene (CYP21B). In the human genome, CYP21B is located within the MHC class III region on the short arm of chromosome 6. Most of the genes in this region are highly polymorphic and crowded. Also the CYP21B gene is accompanied by its pseudogene (CYP21A) and tandemly arranged with two genes of fourth component of complement. This highly complex gene cluster in this area may predispose genetic instability of CYP21, i.e. mutations. In this study, tried to investigate the frequency of duplication and deletion of CYP21 and patterns of the genetic alterations of these genes.We also compared the genetic alteration in normal subjects with those of the CAH patients. The results showed that 15% of the normal korean population have duplication or deletion of CYP21. There was one normal subject with heterozygous deletion of CYP21B. Of the 5 CAH patients examined, 2 were found to show abnormal patterns. One was a large-scale gene conversion and the other a gene conversion associated with deletion involving both CYP21B and C4 locus II gene. Through this study, we carne to the conclusion that the duplication or even deletion of CYP21 and C4 might be quite a common event in the Korean population and these rearrangements must be regarded as polymorphisms. It could contribute to a high incidencs of CAH by providing a genetic pool of instable CYP21.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3335-3340
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• 2016

Background: Oral submucous fibrosis (OSF) is a precancerous condition with a 4 to13% malignant transformation rate. Related to the habit of areca nut chewing it is mainly prevalent in South-east Asian countries where the habit of betel quid chewing is frequently practised. On chewing, alkaloids and polyphenols are released which undergo nitrosation and give rise to N-nitrosamines which are cytotoxic agents. CYP450 is a microsomal enzyme group which metabolizes various endogenous and exogenous chemicals including those released by areca nut chewing. CYP1A1 plays a central role in metabolic activation of these xenobiotics, whereas CYP2E1 metabolizes nitrosamines and tannins. Polymorphisms in genes that code for these enzymes may alter their expression or function and may therefore affect an individuals susceptibility regarding OSF and oral cancer. The present study was therefore undertaken to investigate the association of polymorphisms in CYP1A1 m2 and CYP2E1 (RsaI/PstI) sites with risk of OSF among areca nut chewers in the Northern India population. A total of 95 histopathologically confirmed cases of OSF with history of areca nut chewing not less than 1 year and 80, age and sex matched controls without any clinical signs and symptoms of OSF with areca nut chewing habit not less than 1 year were enrolled. DNA was extracted from peripheral blood samples and polymorphisms were analyzed by PCR-RFLP method. Gene polymorphism of CYP1A1 at NcoI site was observed to be significantly higher (p = 0.016) in cases of OSF when compared to controls. Association of CYP1A1 gene polymorphism at NcoI site and the risk of OSF (Odd's Ratio = 2.275) was also observed to be significant. However, no such association was observed for the CYP2E1 gene polymorphism (Odd's Ratio = 0.815). Our results suggest that the CYP1A1 gene polymorphism at the NcoI site confers an increased risk for OSF.

• Archives of Pharmacal Research
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• 제27권4호
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• pp.415-421
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• 2004

Cytochrome P450 3A4 (CYP3A4) is the most abundant CYPs in human liver, comprising approximately $30\%$ of the total liver CYPs contents and is involved in the metabolism of more than $60\%$ of currently used therapeutic drugs. However, the molecular mechanisms underly-ing regulation of CYP3A4 gene expression have not been understood. Thus, this study has been carried out to gain the insight of the molecular mechanism of CYP3A4 gene expression, investigating if the histone deacetylation is involved in the regulation of CYP3A4 gene expression by proximal promoter. Also SXR was investigated to see if they were involved in the regulation of CYP3A4 proximal promoter activity. Hepa-1 cells were transfected with a plasmid containing ${\~}1kb$ of the human CYP3A4 proximal promoter region (863 to +64 bp) cloned in front of a reporter gene, luciferase, in the presence or absence of SXR. Transfected cells were treated with CYP3A4 inducers such as rifampicin, PCN and RU 486, in order to examine the regulation of CYP3A4 gene expression in the presence or absence of trichostatin A (TSA). In Hepa-1 cells, CYP3A4 inducers increased modestly the luciferase activity when TSA was co-treated, but this increment was not enhanced by SXR cotransfection. Taken together, these results indicated that the inhibition of histone deacetylation was required to SXR-mediated increase in CYP3A4 proximal promoter region when rifampicin, or PCN was treated. Further a trans-activation by SXR may demand other species-specific transcription factors.

• Clinical and Experimental Pediatrics
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• 제48권4호
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• pp.380-386
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• 2005

목 적 : 신생아 황달은 백인에 비해 중국, 일본, 한국 등 동아시아인에서 2배 이상 많이 발생하는 것으로 보아 유전적 연관성이 있을 것으로 생각되어 왔고, 최근 일본인, 타이완 중국인, 한국인에서 UGT1A1 유전자의 Gly71Arg 다형성이 신생아 황달과 연관성이 있다고 보고되었다. 선천적으로 UDP-glucuronosyltransferase(UDPGT)에 결함이 있는 경우에는 부경로(alternative pathway)로 CYP1A2 효소를 자극하여 빌리루빈 대사가 이루어진다. 출생 후 6-14주가 되어야 성인 UDPGT 정상치에 도달하기 때문에 신생아 황달에서 빌리루빈 대사에 CYP1A2 부경로가 중요한 역할을 할 것으로 생각된다. 이에 저자들은 UGT1A1과 CYP1A2 유전자의 다형성이 한국인 신생아 황달의 발생과 어떤 연관성이 있는지 알아보고자 본 연구를 시행하였다. 방 법 : 혈중 빌리루빈 수치가 12 mg/dL 이상의 건강하고, 황달의 다른 위험인자가 없는 만삭아 79명과 대조군 68명으로부터 혈액 0.5 cc를 채취하여 DNA을 분리하였다. UGT1A1 유전자는 Polymerase chain reaction(PCR) 후에 염기서열 분석을 통해서 Gly71Arg 유전자 다형성을 확인하였으며, CYP1A2는 제한효소인 MboII를 이용하여 PCR-restriction fragment length polymorphism 방법과 염기서열 분석을 통해서 T2698G 유전자 다형성을 확인하였다. 결 과 : UGT1A1 유전자의 Gly71Arg 다형성은 변이형 대립 유전자 분포가 환자군에서 32%로 대조군 11%보다 높았다(P<0.0001). CYP1A2 유전자의 다형성은 변이형 유전형 분포가 환자군에서는 41.8%, 대조군에서 32.3%로 환자군이 높았으며 통계학적으로 유의하였다(P=0.015). 변이형 대립유전자의 빈도는 환자군에서 21%로 대조군 19%보다 높았으나 통계학적 유의성은 없었다(P=0.706). Gly71Arg와 T2698G의 변이형 발생의 연관성은 없었다(P=0.635). 결 론 : 한국인의 신생아 황달에서 체내의 빌리루빈 대사의 주경로와 부경로에 작용하는 효소의 유전자인 UGT1A1과 CYP1A2의 다형성이 확인되었고, UGT1A1 유전자의 Gly71Arg 다형성은 신생아 황달과 연관이 있었으나 CYP1A2 유전자의 T2698G 다형성은 신생아의 황달과 연관이 없었다.

• 한국환경성돌연변이발암원학회지
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• 제24권4호
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• pp.155-162
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• 2004

In mammalian, cytochrome P4501A1 (CYP1A1) is very important for metabolism of xenobiotics such as PAHs(Polycyclic aromatic hydrocarbon) and heterocyclic amine, and it is induced by environmental contaminants such as PAHs, TCDD(2,3,7,8-tetrchlorodibenzo-p-dioxin) and 3-MC (3-methylcholanthrene). In fish, like mammalian, when it is exposed to environmental contaminants, they cause specific and sensitive induction of CYP1A. Therefore, induction of CYP1A in fish and mammalian is widely used as a biomarker for exposure of environmental contaminants. In this study, to compare the function of Cyp1a1 in fish with it in mammalian, we have used rainbow trout(Oncorhynchys mykiss) hepatoma cells (RTH-149) and mouse hepatocyte (Hepa-I). in order to examine induction of Cyp1a1 by TCDD, we have used the bioassay system. We examined effects of TCDD on the Cyp1a1-luciferase reporter gene activity, 7-ethoxyresorufin O-deethylase(EROD) activity and Cypa mRNA level.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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• pp.112-112
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• 2001

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental toxin that activates the aryl hydrocarbon receptor (AhR) and disrupts multiple endocrine signaling pathways by enhancing ligand metabolism, altering hormone synthesis, down regulating receptor levels, and interfering with gene transcription. And TCDD-mediated gene transactivation via the AhR has been shown to be dependent upon estrogen receptor (ER) expression in human breast cancer cells. In the present study, we have examined the effect of natural estrogen, phytoestrognes and environmental estrogens on the regulation of CYP1A1 gene expression in MCF-7 human breast cancer cell line. that ER and AhR are co-expressed. pCYP1A1 -luc reporter gene was transiently transfected into MCF-7 cells. These cells were treated with various chemicals and then luciferase assay was carried out. 17be1a-estradiol significantly inhibited TCDD stimulated luciferase activity dose dependently and this inhibition was partially recovered by concomitant treatment of tamoxifen. 17beta-estradiol metabolites, 2-hydroxyestradiol and 16alpha-estriol resulted in less potent inhibitory effect than estradiol and synthetic estrogen, diethylstilbestrol (DES) showed no effect on CYP1A1 gene expression. This study demonstrated that estrogen down-regulated TCDD stimulated CYP1A1 expression via ER mediation. And we have found out that several flavonoids such as genistein, kaempferol, daidzein, naringenin, and alkylphenols such as nonylphenol, 4-octylphenol and resveratrol also inhibited TCDD induced CYP1A1 expression like estrogen.