• Toxicological Research
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• v.33 no.3
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• pp.211-218
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• 2017

Cytochrome P450 1B1 (CYP1B1) acts as a hydroxylase for estrogen and activates potential carcinogens. Moreover, its expression in tumor tissues is much higher than that in normal tissues. Despite this association between CYP1B1 and cancer, the detailed molecular mechanism of CYP1B1 on cancer progression in HeLa cells remains unknown. Previous reports indicated that the mRNA expression level of Herc5, an E3 ligase for ISGylation, is promoted by CYP1B1 suppression using specific small interfering RNA, and that ISGylation may be involved in ubiquitination related to ${\beta}-catenin$ degradation. With this background, we investigated the relationships among CYP1B1, Herc5, and ${\beta}-catenin$. RT-PCR and western blot analyses showed that CYP1B1 overexpression induced and CYP1B1 inhibition reduced, respectively, the expression of $Wnt/{\beta}-catenin$ signaling target genes including ${\beta}-catenin$ and cyclin D1. Moreover, HeLa cells were treated with the CYP1B1 inducer $7,12-dimethylbenz[{\alpha}]anthracene$ (DMBA) or the CYP1B1 specific inhibitor, tetramethoxystilbene (TMS) and consequently DMBA increased and TMS decreased ${\beta}-catenin$ and cyclin D1 expression, respectively. To determine the correlation between CYP1B1 expression and ISGylation, the expression of ISG15, a ubiquitin-like protein, was detected following CYP1B1 regulation, which revealed that CYP1B1 may inhibit ISGylation through suppression of ISG15 expression. In addition, the mRNA and protein expression levels of Herc5 were strongly suppressed by CYP1B1. Finally, an immunoprecipitation assay revealed a direct physical interaction between Herc5 and ${\beta}-catenin$ in HeLa cells. In conclusion, these data suggest that CYP1B1 may activate $Wnt/{\beta}-catenin$ signaling through stabilization of ${\beta}-catenin$ protein from Herc5-mediated ISGylation for proteosomal degradation.

• Molecules and Cells
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• v.20 no.1
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• pp.142-150
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• 2005

Members of the multifunctional Cyp family have been isolated from a wide range of organisms. However, few functional studies have been performed on the role of these proteins as chaperones in red alga. For studying the function of cDNA GjCyp-1 isolated from the red alga (Griffithsia japonica), we expressed and purified a recombinant GjCyp-1 containing a hexahistidine tag at the amino-terminus in Escherichia coli. An expressed fusion protein, $H_6GjCyp-1$ maintained the stability of E. coli proteins up to $50^{\circ}C$. For a functional bioassay for recombinant $H_6GjCyp-1$, the viability of E. coli cells overexpressing $H_6GjCyp-1$ was compared with that of cells not expressing $H_6GjCyp-1$ at $50^{\circ}C$. After high temperature treatment for 1 h, E. coli overexpressing $H_6GjCyp-1$ survived about three times longer than E. coli lacking $H_6GjCyp-1$. Measurement of the light scattering of luciferase (luc) showed that GjCyp-1 prevents the aggregation of luc during mild heat stress and that the thermoprotective activity of GjCyp-1 is blocked by cyclosporin A (CsA), an inhibitor of Cyps. Furthermore, the Cyp-CsA complex inhibited the growth of E. coli under normal conditions. The results of the GjCyp-1 bioassays as well as in vitro studies strongly suggest that Cyp confers thermotolerance to E. coli.

• Environmental Mutagens and Carcinogens
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• v.24 no.3
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• pp.128-136
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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. First, we investigated the effect of on 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. We found that B(k)F significantly up-regulates the level of CYP1A1 prompter activity, EROD and CYP1A1 mRNA. When cells were treated with genistein, it was not changed that EROD and CYP1A1 mRNA, compared to that of control. However, genistein inhibited the B(k)F-induced CYP1A1 promoter activity and mRNA level at high concentration. Furthermore, in this study, effects of HDAC(histone deacetvlase) inhibitors on human prostate cancer cells proliferation were examined. HC-toxin, SAHA and TSA inhibited cell proliferation in PC3 cells. A novel HDAC inhibitor, IN2001 also suppressed the growth of PC3 cells. And IN2001 and SAHA increased S phase and G2/M phase at 12 hrs treatment but cells were arrested G0/G1 phase at 45 hrs treatment. The HC-toxin treatment for 24 hrs and 48 hrs increased G0/G1 at low concentration ($0.1\mu\textrm{m}$) but increased G2/M at more than concentration of $1\mu\textrm{m}$. TSA increased G2/M phase. These findings height the possbility of developing HDAC inhibitors as potential anticancer therapeutic agents for the treatment of prostate cancer.

• Toxicological Research
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• v.32 no.3
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• pp.207-213
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• 2016

Although propolis is one of the most popular functional foods for human health, there have been no comprehensive studies of herb-drug interactions through cytochrome P450 (CYP) inhibition. The purpose of this study was to determine the inhibitory effects of propolis on the activities of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and 3A4 using pooled human liver microsomes (HLMs). Propolis inhibited CYP1A2, CYP2E1 and CYP2C19 with an $IC_{50}$ value of 6.9, 16.8, and $43.1{\mu}g/mL$, respectively, whereas CYP2A6, 2B6, 2C9, 2D6, and 3A4 were unaffected. Based on half-maximal inhibitory concentration shifts between microsomes incubated with and without nicotinamide adenine dinucleotide phosphate, propolis-induced CYP1A2, CYP2C19, and CYP2E1 inhibition was metabolism-independent. To evaluate the interaction potential between propolis and therapeutic drugs, the effects of propolis on metabolism of duloxetine, a serotonin-norepinephrine reuptake inhibitor, were determined in HLMs. CYP1A2 and CYP2D6 are involved in hydroxylation of duloxetine to 4-hydroxy duloxetine, the major metabolite, which was decreased following propolis addition in HLMs. These results raise the possibility of interactions between propolis and therapeutic drugs metabolized by CYP1A2.

• Korean Journal of Medicinal Crop Science
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• v.24 no.1
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• pp.7-13
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• 2016

Background : Ginger has been extensively used in foods and traditional medicines in Asian countries. Despite its frequent consumption in daily life, the mechanism of potential interactions between ginger components-drug has not been examined. To elucidate the mechanism of governing the effects of 6-shogaol, a primary constituent of dried ginger, on human cytochrome P450 (CYP) isoenzymes an incubation studies were carried out using pooled human liver microsome (HLM). Methods and Results : CYP isoenzyme specific substrate was incubated with multiple concentrations of inhibitor, HLM and cofactors. 6-shogaol showed a potent inhibitory effect on CYP2C9, CYP1A2 and CYP2C19 with half maximal inhibitory concentration ($IC_{50}$) values of 29.20, 20.68 and $18.78{\mu}M$ respectively. To estimate the value of the inhibition constant ($K_i$) and the mode of inhibition, an incubation study with varying concentrations of each CYP isoenzyme-specific probe was performed. 6-shogaol inhibited CYP2C9 and CYP2C19 noncompetitively ($K_i=29.02$ and $19.26{\mu}M$ respectively), in contrast, the inhibition of CYP1A2 was best explained by competitive inhibition ($K_i=6.33{\mu}M$). Conclusions : These findings suggest that 6-shogaol may possess inhibitory effects on metabolic activities mediated by CYP1A2, CYP2C9 and CYP2C19 in humans.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.90-90
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• 2002

In order to understand the mechanism of action of TCDD, we have examine the effect of COX-inhibitors on Cyp1a1 activity. We observed the effect of COX-inhibitor on EROD activity in C57BL/6 mouse in vovo. And we also evaluated the effect of COX-inhibitors on mouse cyp1a1 promoter activity in Hepa cell.(omitted)

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1659-1664
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• 2012

TSAHC [4'-(p-toluenesulfonylamido)-4-hydroxychalcone] is a promising antitumorigenic chalcone compound, especially against TM4SF5 (four-transmembrane L6 family member 5)-mediated hepatocarcinoma. We evaluated the potential of TSAHC to inhibit the catalytic activities of nine cytochrome P450 isoforms and of P-glycoprotein (P-gp). The abilities of TSAHC to inhibit phenacetin O-deethylation (CYP1A2), coumarin 6-hydroxylation (CYP2A6), bupropion hydroxylation (CYP2B6), amodiaquine N-deethylation (CYP2C8), diclofenac 4-hydroxylation (CYP2C9), omeprazole 5-hydroxylation (CYP2C19), dextromethorphan O-demethylation (CYP2D6), chlorzoxazone 6-hydroxylation (CYP2E1), and midazolam 1'-hydroxylation (CYP3A) were tested using human liver microsomes. The P-gp inhibitory effect of TSAHC was assessed by [$^3H$]digoxin accumulation in the LLCPK1-MDR1 cell system. TSAHC strongly inhibited CYP2C8, CYP2C9, and CYP2C19 isoform activities with $K_i$ values of 0.81, 0.076, and $3.45{\mu}M$, respectively. It also enhanced digoxin accumulation in a dose-dependent manner in the LLCPK1-MDR1 cells. These findings indicate that TSAHC has the potential to inhibit CYP2C isoforms and P-gp activities in vitro. TSAHC might be used as a nonspecific inhibitor of CYP2C isoforms based on its negligible inhibitory effect on other P450 isoforms such as CYP1A2, CYP2A6, CYP2B6, CYP2D6, CYP2E1, and CYP3A.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.60-66
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• 2002

• Archives of Pharmacal Research
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• v.27 no.4
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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.

• Biomolecules & Therapeutics
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• v.30 no.6
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• pp.510-519
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• 2022

Tofacitinib, a Janus kinase 1 and 3 inhibitor, is mainly metabolized by CYP3A1/2 and CYP2C11 in the liver. The drug has been approved for the chronic treatment of severe ulcerative colitis, a chronic inflammatory bowel disease. This study investigated the pharmacokinetics of tofacitinib in rats with dextran sulfate sodium (DSS)-induced ulcerative colitis. After 1-min of intravenous infusion of tofacitinib (10 mg/kg), the area under the plasma concentration-time curves from time zero to time infinity (AUC) of tofacitinib significantly increased by 92.3%. The time-averaged total body clearance decreased significantly by 47.7% in DSS rats compared with control rats. After the oral administration of tofacitinib (20 mg/kg), the AUC increased by 85.5% in DSS rats. These results could be due to decreased intrinsic clearance of the drug caused by the reduction of CYP3A1/2 and CYP2C11 in the liver and intestine of DSS rats. In conclusion, ulcerative colitis inhibited CYP3A1/2 and CYP2C11 in the liver and intestines of DSS rats and slowed the metabolism of tofacitinib, resulting in increased plasma concentrations of tofacitinib in DSS rats.