• Biomolecules & Therapeutics
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• v.22 no.2
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• pp.155-160
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• 2014

Thelephoric acid is an antioxidant produced by the hydrolysis of polyozellin, which is isolated from Polyozellus multiplex. In the present study, the inhibitory effects of polyozellin and thelephoric acid on 9 cytochrome P450 (CYP) family members (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) were examined in pooled human liver microsomes (HLMs) using a cocktail probe assay. Polyozellin exhibited weak inhibitory effects on the activities of all 9 CYPs examined, whereas thelephoric acid exhibited dose- and time-dependent inhibition of all 9 CYP isoforms ($IC_{50}$ values, $3.2-33.7{\mu}M$). Dixon plots of CYP inhibition indicated that thelephoric acid was a competitive inhibitor of CYP1A2 and CYP3A4. In contrast, thelephoric acid was a noncompetitive inhibitor of CYP2D6. Our findings indicate that thelephoric acid may be a novel, non-specific CYP inhibitor, suggesting that it could replace SKF-525A in inhibitory studies designed to investigate the effects of CYP enzymes on the metabolism of given compounds.

• Environmental Mutagens and Carcinogens
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• v.22 no.3
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• pp.169-174
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• 2002

Resveratrol is known to have potent cancer chemopreventive activity against tumorigenesis caused by 7,12-dimetylbenz［$\alpha$］anthracene(DMBA) which is known to be oxidized to reactive products by cytochrome P450 1B1 (CYP1B1). The effects of resveratrol on the activity of recombinant human P450 1 family enzymes, expressed in Escherichia coli membranes with human NADPH-P450 reductase, were determined by measuring alkoxyresorufin O-dealkylation activity, e.g., ethoxyresorufin O-deethylation (EROD) CYP1A1, methoxyresorufin O-demethylation (MROD), CYP1A2, benzyloxyresorufin-O-debenzylation (BROD), CTP1B1. Resveratrol inhibited CYP1B1 and CYP1A1 activities in a dose-dependent manner with $IC_{50}$/ values of 59 and 10$\mu$M for EROD activity and 1.8 and 30$\mu$M for BROD activity, respectively. Resveratrol had only weak inhibitory effect on CYP1A2 activity ($IC_{50}$/ values of 0.44 mM for EROD and ＞2 mM for MROD). Furthermore, resveratrol did not affect NADPH-P450 reductase activity significantly. Resveratrol inhibited the CYP1B1-dependent EROD activity with a $K_{i}$ of 28 $\mu$M in a non-competitive type manner. these results suggest that resveratrol-derived inhibited of CYP1B1 and CYP1A1 activities may contribute to the suppression of DMBA inducible tumorigenesis observed in extrahepatic tissues.s.

• Biomedical Science Letters
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• v.4 no.2
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• pp.129-135
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• 1998

We have carried out polymerase chain reaction (PCR) to investigate if retropseudogene for CYP2El is present in human genome. PCR primers were designed based on the structure of functional CYP2El gene and used to amplify both functional gene and retropseudogene in one reaction. From the repeated experiments we were able to amplify a previously unidentified CYP2El retropseudogene that was present in human genome. Its detailed structure was confirmed by Southern blotting and DNA sequencing. Nucleotide sequence of this retropseudogene was completely matched up to human liver CYP2El mRNA suggesting that the development of this retropseudogene might be a relatively recent event.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.693-712
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• 2004

The rats with protein-calorie malnutrition (PCM, 5％ casein diet for a period of 4-week) were reported to exhibit 60 and 80％ suppression in the hepatic microsomal cytochrome P450 (CYP) 1 A2 and CYP2C11 levels, respectively, and 40-50％ decreases in CYP2E1 and CYP3A 1/2 levels compared to control (23％ casein diet for a period of 4-week) based on Western blot analysis. In addition, Northern blot analysis showed that CYP1 A2, CYP2E1, CYP2C11, and CYP3A1/2 mRNAs decreased in the state of PCM as well. Hence, pharmacokinetic changes of the drugs in rats with PCM [especially the area under the plasma concentration-time curve from time zero to time infinity (AUC) changes of metabolite(s)] reported from literatures were tried to explain in terms of CYP isozyme changes in the rats. Otherwise, the time-averaged nonrenal clearance ($CL_{NR}$) of parent drug was compared. Pharmacokinetic changes of the drugs in other types of malnutritional state, such as kwashiorkor and marasmus, in both human and animal models were also compared. The drugs reviewed are as follows： diuretics, antibiotics, anticancer agents, antiepileptics, antiarrythmics, analgesics, xanthines, antimalarials, and miscellaneous.

• 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.

• Journal of fish pathology
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• v.23 no.2
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• pp.245-254
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• 2010

Effects of heavy metal ions on the gene expression of cytochrome P4501A (CYP1A) were examined in cultured eel hepatocytes. When the expression of CYP1A mRNA was measured by RT-PCR after incubation of eel hepatocytes with benzo[$\alpha$]pyrene (B[$\alpha$]P) at concentrations of 10-8~10-5 M, the CYP1A expression increased with B[$\alpha$]P treatment in a dose dependent manner, showing significant increase at concentrations more than 10-7 M. When the eel hepatocyte was treated with cadmium (10-6 and 10-5 M), the expression of CYP1A was inhibited and especially at higher concentration (10-5 M). The inhibition of CYP1A expression by cadmium was also observed in cells treated with B[$\alpha$]P. In another study, effects of heavy metal ions on the expression of CYP1A were examined in cultured hepatocytes isolated from eel which was treated previously with B[$\alpha$]P in vivo. Hepatocytes isolated from the liver of eel taken at 48 hours after injection of B[$\alpha$]P (10 mg/kg) were cultured for 2 days with cadmium, copper, lead or zinc (10-6 and 10-5 M). The expression of CYP1A was found to be suppressed by the metal ions compared with the control in which CYP1A was induced with previous treatment of B[$\alpha$]P in vivo. The present results may provide an important basic information for studying the effects of heavy metal ions on CYP1A expression in other species of fish and studying toxicological mechanisms of heavy metal ions in aquatic livings.

• Environmental Mutagens and Carcinogens
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• v.24 no.4
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• pp.180-188
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• 2004

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. 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 daidzein inhibited the B(k)-induced CYP1A1 prompter activity and mRNA level at high concentration. But daidzein exhibited stimulatory effects B(k)F-induced CYP1A1 promoter activity and mRNA level at low concentration. Overall, results from these studies demonstrate flavonoids might interfere the action of B(k) with AhR system to stimulate CYP1A1 gene expression.

• Toxicological Research
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• v.14 no.4
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• pp.587-594
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• 1998

In order to understand the mechanism if the regulation of CYP 1A1 gene expression and ethoxyresorufin deethylase (EROD) activity in ex vivo system, we have studied the action of TCDD and 3MC in the isolated perfused female rat liver. CYP1A1 mRNA level and EROD activity were measured in rat liver that was isolated and perfused with various chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3-methylcholanthrene (3MC), 17$\beta$-estradiol (E$_2$), morin. TCDD or 3MC alone perfusion into female rat liver resulted in increase of CYP 1A1 mRNA level and the magnitude of stimulation was six times higher with TCDD treatment than 3MC treatment. However E$_2$ perfusion into female rat liver showed inhibition of CYP 1A1 mRNA level. When 10$^{-8}$ M E$_2$ was administered concomitantly with either 10$^{-9}$ M TCDD or 10$^{-9}$ M 3MC, stimulated CYP 1A1 mRNA by either TCDD or 3MC was inhibited. Morin was examined for its effects on CYP 1A1 mRNA level and result was similar to that was observed with estrogen. EROD activity was also stimulated with either TCDD or 3MC perfusion, and the magnitude of EROD stiumlation was smaller than that of CYP 1A1 mRNA stimulation in response to TCDD or 3MC perfusion. Unlike CYP1A1 mRNA level, stimulation of EROD activity was greater with 3MC than TCDD. Concomitant perfusion either E$_2$ or morin with TCDD or 3MC inhibited 3MC perfusion or TCDD perfusion stimulated EROD activity. These data suggested that TCDD and 3MC might act diffrently in terms of regulation of CYP 1A1 gene expression in rat liver.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.232-238
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• 2004

Trolox is a hydrophilic analogue of vitamin E. The aim of this study was to investigate its effects on hepatic injury, especially alteration in cytochrome P450 (CYP)-dependent drug metabolism during polymicrobial sepsis. Rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). The rats were treated intravenously with Trolox (2.5 mg/kg) or vehicle, immediately after CLP. Serum aminotransferases and lipid peroxidation levels were markedly increased 24 h after CLP. This increase was attenuated by Trolox. Total CYP content and NADPH-P450 reductase activity decreased significantly 24 h after CLP. This decrease in CYP content was attenuated by Trolox. At 24 h after CLP, there was a significant decrease in the activity of these CYP isozymes: CYP1A1, 1A2, 2B1, and 2E1. However, Trolox differentially inhibited the decrease in CYP isozyme activity. Trolox had little effect on the decrease in CYP1A1 activity but Trolox significantly attenuated decreases in CYP1A2 and 2E1 activities. In fact, Trolox restored CYP2B1 activity to the level of activity found in control rats. Our findings suggest that Trolox reduces hepatocellular damage as indicated by abnormalities in hepatic drug-metabolizing function during sepsis. Our data also indicates that this protection is, in part, caused by decreased lipid peroxidation.