• Environmental Mutagens and Carcinogens
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• v.24 no.3
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• pp.121-127
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• 2004

Cytochrome P4501B1(CYP1B1) is known to be inducible by xenobiotic compounds such as policyclic aromatic hydrocarbon(PAH) and dioxins such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin(TCDD). And these induction of CYP1B1 is also regulated by many categories of chemicals. In order to investigate the effects of several chemicals on CYP1B1 gene expression in Hepa-I and MCF-7 cells, 5' flanking DNA of human CYP1B1 was cloned into pGL3 basic vector containing luciferase gene, and then transfected into these cells. After treatment of chemicals, the luciferase activity was measured. CYP1B1 enzyme metabolize PAHs and estradiol. CYP1B1 metabolize estradiol to 4-hydrozyestradiol that is considered as carcinogenic metabolite. Luciferase activity was induced about 20 folds over that control by 1 nM TCDD (2,3,7,8-tetrachloto-p-dioxin). Recent industrialized society, human has been widely been exposed to widespread environmental contaminants such as PAHs(polycyclic aromatic hydrocarbon) that are originated from the imcomplete combustion of hydrocarbons. PAHs are known to be ligands of the AhR(aryl hydrocarbon receptor). Induction of cytochrome P4501B1(CYP1B1) in cell culture is widely used as a biomarker for PAHs. Therefore we have studied the effect of PAHs in the human breast cancer cells MCF-7 to evaluate bioactivity of PAHs. We have used the United State of America EPA selected 13 different PAHs, PAHs mixtures and extracts from environmental samples to evaluate the bioassay system. We examined effects of PAHs on the CYP1B1-luciferase reporter gene and CYP1B1 mRNA level. Benzo(k)fluoranthene and dibenzo(a, h)anthracene showed strong response to CYP1B1 promoter activity stimulation, and also CYP1B1 mRNAs increase in MCF-7 cells in a concentration-dependent manner. Acenaphthene, anthracene, benzo(b)fluoranthene, fluorene, fluoranthene, anphthanlene, pyrene, phenanthrene and carbazole were weak responders in MCF-7 cells. RT-PCR analysis indicated that PAHs significantly up-regulate the level of CYP1B1 mRNA.

• Environmental Mutagens and Carcinogens
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• v.24 no.4
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• pp.198-205
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• 2004

Cytochrome P4501B1(CYP1B1) is known to be inducible by xenobiotic compounds such as policyclic aromatic hydrocarbon(PAH) and dioxins such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin(TCDD). And these induction of CYP1B1 is also regulated by many categories of chemicals. In order to investigate the effects of several chemicals on CYP1B1 gene expression in Hepa-I and MCF-7 cells, 5' flanking DNA of human CYP1B1 was cloned into pGL3 basic vector containing luciferase gene, and then transfected into these cells. After treatment of chemicals, the luciferase activity was measured. CYP1B1 enzyme metabolize PAHs and estradiol. CYP1B1 metabolize estradiol to 4-hydrozyestradiol that is considered as carcinogenic metabolite. Recent industrialized industrialized society, human has been widely been exposed to widespread environmental contaminants such as PAHs(polycyclic aromatic hydrocarbon) that are originated from the imcomplete combustion of hydrocarbons. PAHs are known to be ligands of the AhR(aryl hydrocarbon receptor). Induction of cytochrome P4501B1(CYP1B1) in cell culture is widely used as a biomarker for PAHs. Therefore we have studied the effect of PAHs in the human breast cancer cells MCF-7 to evaluate bioactivity of PAHs. We have used the United State of America EPA selected 13 different PAHs, PAHs mixtures and extracts from environmental samples to evaluate the bioassay system. We examined effects of PAHs on the CYP1B1-luciferase reporter gene and CYP1B1 mRNA level. Benzo(k)fluoranthene and dibenzo(a, h)anthracene showed strong response to CYP1B1 promoter activity stimulation, and also CYP1B1 mRNAs increase in MCF-7 cells in a concentration-dependent manner. RT-PCR analysis indicated that PAHs significantly up-regulate the level of CYP1B1 mRNA. Some flavonoids such as genistein, daidzein, chrysin, naringenin and morin were also investigeted. These flavonoids decreased B(k)F infuced luciferase activity at low concentration. But, these flavonoids exhibited stimulatory effect at high concentration.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.23-26
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• 2016

Breast cancer (BC) is the most common cancer and the second cause of mortality in women all around the world. It is caused by several factors including genetic determinants, so that both genetic susceptibility factors and environmental factors are involved in the etiology. Significance of genes functioning in steroid hormone synthesis and metabolism are well established in breast cancer susceptibility. In this study, 134 women with BC and 135 normal controls were analyzed for their genotypes for the polymorphisms, rs743572, rs10046 and rs4646903, resided in CYP17, CYP19 and CYP1A1 genes, respectively. Significant differences in distributions of allele and genotype frequencies were found for the rs10046 polymorphism in CYP19 (p-value=0.01, OR (CI 95%) =1.59 (1.1-2.3), p-value=0.04, OR (CI 95%) =1.7 (1.1-2.5) respectively). For rs743,572 and rs 4646903 polymorphisms, no significant associations were observed. A significant association was observed between the rs10046 polymorphism of the CYP19gene and breast cancer in Iranian patients. Due to inconsistent previous results, more studies in different populations with larger sample sizes are indicated.

• Environmental Mutagens and Carcinogens
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• v.24 no.3
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• pp.143-150
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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.

• Environmental Mutagens and Carcinogens
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• v.24 no.4
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• pp.171-179
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• 2004

Cytochrome P4503A4(CYP3A4) is the most abundnat CYPs in human liver, comparising approximately 30% of the total liver CYPs contents ans is involbed in the metabolism of more than 60% of currently used therapeutic drugs. The expression of CYP3A4 is induced by a variety of structurally unrelated xonobiotics including the antibiotic rifampicin and endogenous hormones, and might be mediated through steroid and xenobiotic receptor(SXR) system. The molecular mechanisms underlying regulation of CYP3A4 gene expression hae not been understood. In order to gain the insight of the molecular mechanism of CYP3A4 gene expression, study has been undertaken to investigate if the histone deacelylation is involved in the regulation of CYP3A4 gene expression by proximal promoter or not. Also SXR was investigated to see if they were involved in the regulation of CYP3A4 proximal promoter activity. HepG2 or Hena-I cells were transfected with a plasmid containing~1kb of the CYP3A4 proximal promoter region (-863 to +64bp) cloned in front of a reporter gene, luciferase, in the presence or absence of SXR or hER. Transfected cells were treated with CYP3A4 inducers such as rifampicin, PCN and RU 486, or with estradiol, in order to exmine to regulation of CYP3A4 gene expression in the presence or absence of trichostatin A (TSA). In HepG2 cells, CYP3A4 inducers and estradiol increased significantly the luciferase activity by CYP3A4 proximal promoter, only when TSA was co-treated after SXR cotransfection. In the case of Hepa-I cells CYP3A4 inducers and estradiol incressed modestly the luciferase activity when TSA was co-treated, but this increment was not enhanced by SXR cotransfection in contrast to HepG2 cells. 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. Futher a trans-activation by SXR may demand other species-specific transcription factors.

• Environmental Mutagens and Carcinogens
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• v.24 no.4
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• pp.189-197
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• 2004

We investigated the effect of dietaty flavonoid, such as CYP1A1 promoter activity, 7-ethoxyresorufin-O-deethylase(EROD) activity and CYP1A1 mRNA expression induced by benzo(k)fluoranthene(B(k)F) in MCF-7 cells. Based on the three criteria of frequency of occurrence in the environment, toxicity and potential exposure to humans, B(k)F is one of the top-listed PAHs. We found that B(k)F significantly up-regulates the level of CYP1A1 promoter activity, EROD and CYP1A1 mRNA. When cells were treated with morin alonem, it was not changed that EROD and CYP1A1 mRNA, compared to that of control. However, morin inhibited the B(k)-induced CYP1A1 prompter activity and mRNA level at high concentration. But morin exhibited stimulatory effects B(k)F-induced CYP1A1 promoter activity and mRNA level at low concentration. Overall, results from these studies demonstrate morin might interfere the action of B(k) with AhR system to stimulate CYP1A1 gene expression. CYP1A1 is known to be inducible by xenobiotic compouds such as polyciclic aromatic hydrocarbons(PAHs) and 2,3,7,8-tetrachloro-dibenzo-p-dioxin(TCDD). These chemicals have been identified worldwide and can have a significant impact on the human health and well being of human and wildlife. Given these issues, the detection and quantification of these chemicals in biological, environmental and food samples is important.

• Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.64-69
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• 2006

Cytochrome P450 (CYP1A) gene expression in the liver and sex steroid levels in plasma were investigated in olive flounder (Paralichthys olivaceus) exposed to tributyltin (TBT) and benzo[a]pyrene (BaP). We constructed a cDNA library and cloned a 230-base sequence encoding partial CYP1A DNA. The CYP1A gene expression level was estimated using northern blotting. Hepatic CYP1A mRNA levels in fish injected with BaP at 10 mg/kg body weight (b.w.) increased for 48 h after injection. However, fish injected with both BaP and TBT at 10 mg/kg b.w. showed no significant changes in CYP1A mRNA level after 48 h. Plasma concentrations of testosterone and $17{\beta}$-estradiol were not significantly different in males and females injected with BaP and TBT. We suggest that TBT-induced suppression of BaP bioactivity should be interpreted with caution in biomonitoring field studies.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.91-91
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• 2003

We have studied the mechanism of action of TCDD on CYP1A1 promoter activity in both Hepa I and MCF-7 cells using transient transfection system with plAl-Luc reporter gene. When HDAC inhibitors, such as trichostatin A, HC toxin and a novel HDAC inhibitor, IN2001 were cotreated with TCDD to the cells transfected with plAl-Luc reporter gene, the basal promoter activity of CYP1A1 was increased by HDAC inhibitors. Also, in MCF-7 human breast cancer cells, HDAC inhibitors, such as IN2001 and trichostatin A increased the basal activity of CYP1A1 promoter but TCDD stimulated CYP1A1 promoter activity was not changed by HDAC inhibitors. And, in stably-transfected Hepa I cells with plAl-Luc, HDAC inhibitors increased the basal promoter activity only.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.81-81
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• 1997

We previously demonstrated an enhancer-like positive regulatory element within a 259-bp sequence (-2352 to-2094 bp) of the human CYP1A2 gene in HepG2 cells. Three protein binding sites were identified by DNase I footprint analyses within the 259-bp sequence: protected region A PRA ( -2283 to-2243 bp), PRB (-2218 to-2187 bp), and PRC (-2124 to-2098 bp) (I. Chung and E. Bresnick, Mol. Pharmacol. 47, 677-685, 1995). In the present study, the functional significance of those protected regions was examined. Transfection experiments with deletion and substitution mutants defined the PRB and PRC as containing positive and negative regulatory elements, respectively. Human breast carcinoma MCF-7 cells were cotransfected with a hepatocyte nuclear factor-1 (HNF-1) expression vector and CYP1A2 promoter-or thymidine kinase promoter-luciferase remoter gene constructs. HNF-1, which contributes to the liver specificity of genes, enhanced reporter gene activity in a PRC sequence-dependent manner. These results suggested that PRC could exist bound to a repressor which was displaceable by other transcription factors such as HNF-1. Results obtained by transfection of HepG2 hepatoma cells with various PRB substitution mutant-luciferase gene fusion constructs indicated that the entire sequence of PRB was necessary for promoter activity. Consequently, the regulation of CYP1A3 expression is very complex, requiring a number of both positive and negative regulatory factors.

• BMB Reports
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• v.43 no.8
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• pp.530-534
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• 2010

Cytochrome P450 (CYP) 1A2 gene polymorphisms are thought to be involved in the metabolism of theophylline (TP). We aimed to investigate the effect of CYP1A2*1C, CYP1A2*1D, CYP1A2*1E, and CYP1A2*1F polymorphisms of the CYP1A2 on TP metabolism by PCR-RFLP in 100 Turkish patients with chronic obstructive pulmonary disease (COPD) receiving TP. One hundred and one healthy volunteers were included as control group. The genotype frequencies of the CYP1A2*1D and CYP1A2*1F were found to be significantly different in the patients compared to the controls. The "T" allele at -2467 delT and the "C" allele at -163 C > A in the CYP1A2 displayed association with a significantly increased risk for COPD. "T" allele at -2467 delT was also associated with a high risk of disease severity in COPD. In conclusion, our data suggest that genetic alterations in CYP1A2 may play a role both in the pharmacogenetics of TP and in the development of COPD.