• Journal of Life Science
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• v.26 no.1
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• pp.42-49
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• 2016

The retinoic acid (RA) plays an important role in the growth and development of many cells, and bioactive RA concentration is regulated by several enzymes, including CYP26A1. The expression of the CYP26A1 gene is regulated by RA, and the CYP26A1 gene is one of the candidates for RA-responsive genes. Although CYP26A1 genes are cloned from several animals, cloning of the CYP26A1 gene from cows has not been reported yet. The promoter region of CYP26A1 from cows was cloned by PCR and analyzed by sequence alignment with human and mouse CYP26A1. The RA-responsive element (RARE), DR-5 (ttggg), was located in this region and was perfectly conserved. The promoter region of bovine CYP26A1, which contains DR-5, was ligated to the luciferase reporter gene on transient transfection assays. The expression of CYP26A1-Luc promoter was activated by ATRA treatment in lung-derived mtCC cells. Co-transfection with RAR-α or -β with ATRA significantly activates the expression of CYP26A1-Luc promoter; however, it was less effective with either RAR-γ or RXR-γ. In addition, the endogenous gene expressions measured by Q-RT-PCR in mtCC cells were not significantly affected by ATRA treatment for 2 days; however, the expression of the endogenous CYP26A1 gene was diminished sharply at day 3 with ATRA treatment. In conclusion, the promoter region of bovine CYP26A1 contains conserved DR-5 RARE, which functions as a binding site for RAR-α or -β, and it is involved in the regulation of CYP26A1 gene expression and the control of RA signaling in mtCC cells.

• Environmental Mutagens and Carcinogens
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• v.26 no.3
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• pp.86-88
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• 2006

Cytochrome P450 1A2 (CYP1A2) is a xenobiotic metabolizing enzyme that is tissue-specifically expressed in the mammalian liver. In this study, the extent of CYP1A2 promoter methylation was analyzed to determine its potential role in the regulation of CYP1A2 in diethylnitrosamine (DEN)-induced mouse liver tumors. CYP1A2 mRNA was under-expressed about three fold in DEN-induced liver tumors compared to age-matched control livers. The CYP1A2 promoter was hypermethylated in DEN-induced liver tumors compared to controls, especially in a promoter domain close to the coding region. These results suggest that promoter methylation is involved in the regulation of CYP1A2 in mouse liver tumors.

• Toxicological Research
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• v.26 no.3
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• pp.171-175
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• 2010

The human genome contains approximately 13 orphan cytochrome P450 (P450, CYP) genes, of which the apparent function or substrate has not been identified. However, they seem to possess their own biological relevance in some tissues or developmental stages. Here, we characterized the heterologously expressed CYP2W1, an orphan P450 enzyme. The recombinant CYP2W1 protein containing a $6{\times}$(His)-tag at Nterminus has been expressed in Escherichia coli and purified. Expression level of CYP2W1 holoenzyme was around 500 nmol P450 holoenzyme per liter culture medium. The reduced CO difference spectrum of CYP2W1 showed a maximum absorption at 449 nm. CYP2W1 indicated the significant induction to bioactivate Trp-P-1, MeIQ, and IQ in E. coli DJ701 tester strain. However, the bioactivation of B[$\alpha$]P, and NNK by CYP2W1 was relatively low. The model structure of CYP2W1 suggested the characteristic P450 folds with the lengths and orientations of the individual secondary elements. The F-G loop is situated on the distal side of heme to accommodate the flexibility of active site of CYP2W1. These studies can provide useful information for the finding of its biological roles and structure-function relationships of an orphan CYP2W1 enzyme.

• Journal of Pharmaceutical Investigation
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• v.37 no.6
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• pp.369-376
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• 2007

Cyclosporine (CsA) and tacrolimus (FK506) have a narrow therapeutic range, and their pharmacokinetic (PK) characteristic varies among individual. They are also substrates for cytochrome P450 (CYP) 3A4, 3A5 genes, and P-glycoprotein, the product of the multidrug resistance 1 (MDR1). The aims were to investigate the relationship between CYP3A and MDR1 genotypes and their PK parameters among healthy subjects. We investigated the genotype for CYP3A and MDR1 gene in human using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. After oral administration of CsA and FK506 (100 mg and 1 mg, respectively), whole blood samples were taken up to 24 hours. Blood CsA and FK506 concentrations were measured by LC/MS/MS. Each PK parameters were compared using Kruskal-Wallis test according to the CYP3A and MDR1 genotype. We found that the values of AVC for CsA were significantly different among CYP3A5 and MDR1 exon 26 (C3435T) genotypes (P=0.037 and P=0.049). On the other hand, the AUC for FK506 was significantly different only among CYP3A5 genotypes (P=0.013). The results clearly demonstrate the effects of CYP3A5 and MDR1 exon 26 on Cys and FK506 disposition.

• Archives of Pharmacal Research
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• v.26 no.1
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• pp.47-52
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• 2003

The aim of this study was to investigate the effects of trauma on alterations in cytochrome P450 (CYP 450)-dependent drug metabolizing function and to determine the role of Kupffer cells in hepatocellular dysfunction. Rats underwent closed femur fracture (FFx) with associated soft-tissue injury under anesthesia, while control animals received only anesthesia. To deplete Kupffer cells in vivo, gadolinium chloride (GdCl$_3$) was injected intravenously via the tail vein at 7.5 mg/kg body wt., 1 and 2 days prior to FFx surgery. At 72 h after FFx, serum alanine aminotransferase (ALT) activity was increased, and this increase was attenuated by GdCl$_3$ pretreatment. Serum aspartate aminotransferase (AST) and lipid peroxidation levels were not changed by FFx. Hepatic microsomal CYP 450 content and aniline p-hydroxylase (CYP 2E1) activity were significantly decreased; decreases that were not prevented by GdC1$_3$. The level of CYP 2B1 activity was decreased by Kupffer cell inactivation, but not by FFx. There were no significant differences in the activities of CYP 1A1, CYP 1A2 and NADPH-CYP 450 reductase among any of the experimental groups. Our findings suggest that FFx trauma causes mild alterations of hepatic CYP 450-dependent drug metabolism, and that Kupffer cells are not essential for the initiation of such injury.

• 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.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4689-4695
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• 2014

Background: A great number of studies have shown that cytochrome P450 1A1 (CYP1A1) genetic polymorphisms, CYP1A1 Msp I and CYP1A1 Ile/Val, might be risk factors for digestive tract cancers, including esophageal cancer (EC), gastric cancer (GC), hepatic carcinoma (HC), as well as colorectal cancer (CC), but the results are controversial. In this study, a meta-analysis of this literature aimed to clarify associations of CYP1A1 genetic polymorphisms with digestive tract cancers susceptibility in Chinese populations. Materials and Methods: Eligible case-control studies published until December 2013 were retrieved by systematic literature searches from PubMed, Embase, CBM, CNKI and other Chinese databases by two investigators independently. The associated literature was acquired through deliberate search and selection based on established inclusion criteria. Fixed-effects or random-effects models were used to estimate odds ratios (ORs and 95%CIs). The meta-analysis was conducted using Review Manager 5.2 and Stata 12.0 softwares with stability evaluated by both stratified and sensitivity analyses. Moreover, sensitivity analysis and publication bias diagnostics confirmed the reliability and stability. Results: Eighteen case-control studies with 1,747 cases and 2,923 controls were selected for CYP1A1 MspI polymorphisms, and twenty case-control studies with 3, 790 cases and 4, 907 controls for the CYP1A1 Ile/Val polymorphisms. Correlation associations between CYP1A1 Ile/Val polymorphisms and digestive tract cancers susceptibility were observed in four genetic models in the meta-analysis (GG vs AA:OR= 2.03, 95%CI =1.52- 2.72; AG vs AA: OR=1.26, 95%CI =1.07-1.48; [GG+AG vs AA] :OR =1.42, 95%CI=1.20-1.68, [GG vs AA+AG]:OR=1.80, 95%CI =1.40-2.31). There was no association between CYP1A1 Msp I polymorphisms and digestive tract cancers risk. Subgroup analysis for tumor type showed a significant association of CYP1A1 Ile/Val genetic polymorphisms with EC in China. However, available data collected by the study failed to reveal remarkable associations of GC or HC with CYP1A1 Ile/Val genetic polymorphisms and EC, GC or CC with CYP1A1 MspI genetic polymorphisms. Conclusions: Our results indicated that CYP1A1 Ile/Val genetic polymorphisms, but not CYP1A1 Msp I polymorphisms, are associated with an increased digestive tract cancers risk in Chinese populations. Additional well-designed studies, with larger sample size, focusing on different ethnicities and cancer types are now warranted to validate this finding.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.631-637
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• 2003

Chloroquine has been used for many decades in the prophylaxis and treatment of malaria. It is metabolized in humans through the N-dealkylation pathway, to desethylchloroquine (DCQ) and bisdesethylchloroquine (BDCQ), by cytochrome P450 (CYP). However, until recently, no data are available on the metabolic pathway of chloroquine. Therefore, the metabolic pathway of chloroquine was evaluated using human liver microsomes and cDNA-expressed CYPs. Chloroquine is mainly metabolized to DCQ, and its Eadie-Hofstee plots were biphasic, indicating the involvement of multiple enzymes, with apparent $K_m and V_{max}$ values of 0.21 mM and 1.02 nmol/min/mg protein 3.43 mM and 10.47 nmol/min/mg protein for high and low affinity components, respectively. Of the cDNA-expressing CYPs examined, CYP1A2, 2C8, 2C19, 2D6 and 3A4/5 exhibited significant DCQ formation. A study using chemical inhibitors showed only quercetin (a CYP2C8 inhibitor) and ketoconazole (a CYP3A4/5 inhibitor) inhibited the DCQ formation. In addition, the DCQ formation significantly correlated with the CYP3A4/5-catalyzed midazolam 1-hydroxylation (r=0.868) and CYP2C8-catalyzed paclitaxel 6$\alpha$-hydroxylation (r = 0.900). In conclusion, the results of the present study demonstrated that CYP2C8 and CYP3A4/5 are the major enzymes responsible for the chloroquine N-deethylation to DCQ in human liver microsomes.

• Journal of Preventive Medicine and Public Health
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• v.31 no.1 s.60
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• pp.1-14
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• 1998

The genetically determined CYP2D6 activity as considered to be associated with cancer susceptibility with inter-individual variation. Genetic polymorphism of CYP2D6(B) and CYP2D6(T) was determined by the two polymerase chain reaction(PCR) and BstN1 and EcoN1 restriction fragment length polymorphisms(RFLP) for 67 lung cancer cases and 95 healthy volunteer controls. The cases were composed of 26 squamous cell carcinoma, 14 small cell carcinoma, 10 adenocarcinoma, 3 large cell undifferentiated carcinoma, and 14 not histologically diagnosed. The results were gained from the 142 subjects (57 cases and 85 controls) who observed successfully in two PCR and BstNl/EcoN1 RELP. Only one and no mutant allele of the CYP2D6(B) and CYP2D6(T) gene was detected, that is, the frequency of mutant allele was very low; 0.7%(1/142) and 0%(0/142), respectively. Detected mutant allele of the CYP2D6(B) was beterozygous type(WM). The odds ratios for lung cancer susceptibility with CYP2D6(B) and CYP2D6(T) genotype were not calculated. These results are similar to the previous understanding that the mutant allele is very rare in Orientals compared to Caucasians, therefore, it considered that CYP2D6(B) and CYP2D6(T) genotypes have maybe no association with lung cancer susceptibility in Koreans. This is the basic data of CYP2D6(B) and CYP2D6(T) genotypes for Koreans. It would be hepful for further study to determine lung cancer susceptibility of Koreans with the data about CYP1A1, CYP2E1, GSTM1 from future study.