• 한국전자통신학회논문지
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• 제13권3호
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• pp.579-586
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• 2018

빅데이터에 대한 관심이 증가하면서 데이터로부터 의미 있는 정보의 추출 및 예측은 중요한 연구분야가 되고 있다. 본 연구에서는 신약개발과정에서 필요한 후보약물의 약리적인 활성을 분석하기 위한 데이터를 획득하고 이를 기반으로 의미 있는 예측 분석을 하고자 한다. 신약개발과정에서 대사반응 된 신약후보물질의 약리적인 활성 연구는 신약개발 성공률을 높이기 위해 필요한 단계이다. 본 연구에서, 약용 후보물질의 체내 효소 반응 유무를 예측하기 위해, 유사도 모델들을 적용 분석하였다. 유사도 모델의 군집별 특성을 반영하여 13개의 모델을 선택하여 효소 반응 예측을 수행하였다. 이들 모델들을 민감도와 AUC를 기반으로 비교 평가하였다. 평가 모델들 중, 효소 사이의 반응성을 예측하는데 있어서 Simpson coefficient 모델이 가장 좋은 성능을 보였다. 분석된 유사도 모델 전체를 웹 서비스로 구축하였다. 제안된 모델은 반응정보의 추가에 동적으로 대응 할 수 있으며 신약개발시간 단축 및 비용 절감에 기여할 것으로 여겨진다.

• Toxicological Research
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• 제17권
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• pp.145-155
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• 2001

Cytochrome P4502C19 (CYP2C19) is one of human polymorphic xenobiotic-metabolizing enzymes. The enzyme has been reported to catalyze more than 70 substrates, involving more than 100 reactions. These include several classes of therapeutic agents (e.g. anti-microbial. cardiovascular, psycho-active, etc.), sex hormones and insecticides. Associations of the CYP2C19 genotype/phenotype with individual differences in drug efficacy (e.g. diazepam, omeprazole, proguanil) and toxicity (e.g. mephenytoin, barbiturates) have been documented by many investigators. At least 11 allelic variants of CYP2C19 gene were reported to date. Most of the mutant alleles found in the poor metabolizer (PM) led to the production of truncated and/or inactive proteins. Except for the exon 6, single-nucleotide mutations were reported in all nine exons of the gene. Genetic polymorphism of CYP2C19 shows marked interethnic variation with the population frequencies of PM phenotype ranging from 1∼2% up to more than 50%. The prevalence of CYP2C19 PM tends to be higher in Asian and certain Pacific Islanders than other race or ethnic specificity. Genotyping results of CYP2C19 also revealed that there are different proportions of individual mutant alleles among ethnic populations. This may, in part, explains the interethnic difference in the metabolism of certain drugs (i.e. diazepam), though they were from the same CYP2C19 phenotype. Recently, our research group has studied the genotype and phenotype of CYP2C19 and found that the PM frequency (7∼8%) in Thais is lower than other Asian populations. Molecular and clinical impacts of this finding warrant to further investigation.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.179-182
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• 2013

Human cytochrome P4502E1 (CYP2E1) is a well-conserved xenobiotic-metabolizing enzyme expressed in liver, kidney, nasal mucosa, brain, lung, and other tissues. CYP2E1 is inducible by ethanol, acetone, and other low-molecular weight substrates and may mediate development of chemically-mediated cancers. CYP2E1 polymorphisms alter the transcriptional activity of the gene. This study was conducted in order to investigate the allele frequency variation in different populations of Andhra Pradesh. Two hundred and twelve subjects belonging to six populations were studied. Genotype and allele frequency were assessed through TaqMan allelic discrimination (rs6413419) and polymerase chain reaction-sequencing (-1295G>C and -1055C>T) after DNA isolation from peripheral leukocytes. The data were compared with other available world populations. The SNP rs6413419 is monomorphic in the present study, -1295G>C and -1055C>T are less polymorphic and followed Hardy-Weinberg equilibrium in all the populations studied. The -1295G>C and -1055C>T frequencies were similar and acted as surrogates in all the populations. Analysis of HapMap populations data revealed no significant LD between these markers in all the populations. Low frequency of $CYP2E1^*c2$ could be useful in the understanding of south Indian population gene composition, alcohol metabolism, and alcoholic liver disease development. However, screening of additional populations and further association studies are necessary. The heterogeneity of Indian population as evidenced by the different distribution of $CYP2E1^*c2$ may help in understanding the population genetic and evolutionary aspects of this gene.

• Toxicological Research
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• 제11권2호
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• pp.205-213
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• 1995

This study was undertaken to investigate the effects of organic solvents on xenobiotic metabollzing enzyme system in vivo by meaas of experimental conditions i.e. (1) single group which was treated by benzene (B), toluene (T) and xylene (X), respectively, (2) combination group which was treated by mixture of benzene+toluene (BT), benzene+xylene (BX), and toluene+xylene (TX), respectively, (3) mixture group which was treated by benzene+ toluene+xylene mixture (M), and to interpreat the interaction between the organic solvents metabolizing enzymes. 1. The contents of cytochrome P-450 in liver microsomes were increased (p < 0.01) in organic solvents treated groups, and the contents of cytochrome P-450 were increased by following order of B < T < M < BT=BX < X < TX. 2. The activity of cytochrome P-450 dependent AHHase was significantly higher in organic solvents treated groups than in control group (p < 0.01), and the activity of AHHase was increased by following order of B < T < BT=BX=TX=xylene < M. 3. The activity of NADPH P-450 reductase was significantly higher in organic solvents treated groups than in control group (p < 0.01), and the order of M < combinated group < X < T

• Molecular & Cellular Toxicology
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• 제2권2호
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• pp.75-80
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• 2006

Biomarkers identify various stages and interactions on the pathway from exposure to disease. The three categories of biomarkers are those measuring susceptibility, exposure and effect. Susceptibility biomarkers are identifiable genetic variations affecting absorption, metabolism or response to environmental agents. Biomarkers of exposure indicate the amount of a foreign compound that is absorbed into the body. Biological measurements performed on human tissues are vastly expanding the capabilities of classical epidemiology, which has relied primarily on estimates of human exposure derived form chemical levels in the air, water, and other exposure routes. Biomarkers of exposure indicate the amount of a foreign compound that is absorbed into the body. Biological measurements performed on human tissues are vastly expanding the capabilities of classical epidemiology, which has relied primarily on estimates of human exposure derived form chemical levels in the air, water, and other exposure routes. The biomarker response is typical of chemical pollution by specific classes of compound, such as (i) heavy metals (mercury, cadmium, lead, zinc), responsible for the induction of metallothionein synthesis, and (ii) organochlorinated pollutants (PCBs, dioxins, DDT congeners) and polycyclic aromatic hydrocarbons (PAHs), which induce the mixed function oxygenase (MFO) involved in their bio transformations and elimination. Currently genomic researches are developed in human cDNA clone subarrays oriented toward the expression of genes involved in responses to xenobiotic metabolizing enzymes, cell cycle components, oncogenes, tumor suppressor genes, DNA repair genes, estrogen-responsive genes, oxidative stress genes, and genes known to be involved in apoptotic cell death. Several research laboratories in Korea for kicking off these Environmental Genomics were summarized.

• Preventive Nutrition and Food Science
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• 제13권4호
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• pp.269-275
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• 2008

Dandelion (Taraxacum officinale) has been widely used as an anti-inflammatory agent in oriental medicine. In the current study, we investigated the protective effect, and the possible mechanism, of dandelion extracts against ethanol-induced acute hepatotoxicity in C57BL/6 mice. Dandelion water and ethanol extract was administered at 2 g/kg body weight (BW) once daily for 7 consecutive days, whereas control and ethanol groups received water by gavage. Ethanol (50% ethanol; 6 g/kg BW) was administered 12 hr before sacrificing the mice in order to generate liver injury. Significantly increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities as well as liver triglyceride (TG) and cholesterol levels were attenuated by dandelion supplementation. In addition, dandelion extracts not only enhanced alcohol dehydrogenase (ADH) and anti-oxidative enzyme activities, but reduced lipid peroxidation. Cytochrome P450 2E1 (CYP 2E1), one of the critical enzymes xenobiotic metabolism, expression was lower with ethanol treatment but restored by dandelion supplementation. These results were confirmed by improved histopathological changes in fatty liver and hepatic lesions induced by ethanol. In conclusion, dandelion could protect liver against ethanol administration by attenuating of oxidative stress and inflammatory responses.

• 대한의생명과학회지
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• 제6권1호
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• pp.29-36
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• 2000

실험동물에 있어서 간조직의 손상 정도에 미치는 xenobiotics의 투여기간에 의한 영향을 검토할 목적으로 hepatotoxin의 일종인 bromobenzene의 투여 횟수에 의한 간손상 정도와 이의 기전을 구명 한 결과는 다음과 같다. 흰쥐에 1일 간격으로 bromobenzene (400 mg/kg)을 복강으로 1회, 3회 및 6회 투여한 실험군을 대상으로 하여 실시한 실험에서 혈청 alanine aminotransferase (ALT)의 활성 및 체중 당 간 무게는 bromobenzene을 1회 투여 한 1일째에는 대조군과 별다른 변동을 볼 수 없었으나 3회 투여 한 3일째에는 유의하게 증가되었으며, 이후 6일째 6회 투여한 실험군에서는 체중 당 간 무게 및 혈청 ALT활성이 3일째 보다 현저히 감소되어 오히려 대조군과 유사하였다. 이와 같이 투여 횟수의 증가에 따른 간손상의 정도가 투여 횟수와 비례하지 않은 것이 어떠한 기전에 의해서 나타나는지를 구명하기 위해 bromobenzene 대사에 관여하는 간조직 중 aniline hydroxylase 및 glutathione S-transferase 활성과 glutathione (GSH) 함량을 측정한 결과, 이들 대사효소 및 GSH 이용률이 bromobenzene 6회 투여군에서 1회 및 3회 투여군 보다 높게 나타났다. 이상 실험 결과를 종합해 볼 때 어떤 독성물질이 생체에 계속 폭로 시 어느 시점에서 중독현상이 경감되는 것은 이 독성물질의 대사율을 증가시켜 해독하려는 생리적응현상이 일어 날 수 있다는 가설을 제시할 수 있다.

• 생명과학회지
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• 제21권4호
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• pp.481-485
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• 2011

T0901317은 핵수용체 전사인자인 liver X receptor (LXR, NR1H2/3)의 강력한 합성 리간드이다. 그러나, T0901317은 farnesoid X receptor (FXR, NR1H4)와 pregnane X receptor (PXR, NR1I2)에 대해 작용물질(agonist) 로, androgen receptor (AR, NR3C4)와 rertinoid-related orphan receptor-${\alpha}$ (ROR-${\alpha}$, NR1F1)에 대해 길항제(antagonist)로 작용하여, LXR외에 적어도 다른 4종의 핵수용체에 대해 그 활성을 조절한다고 보고되었다. 우리는 T0901317이 또 다른 핵수용체인 constitutive androstane receptor (CAR, NR1I3)에 대해 저해제로 기능함을 확인 하였다. CAR는 이미 T0901317에 의해 기능이 조절된다고 알려진 PXR, FXR, LXR과 더불어 간에서 생체이물과 콜레스테롤의 대사작용에 중요한 역할을 하므로 T0901317에 의해 CAR의 활성이 조절된다는 사실은, 간세포에서 T0901317을 이용한 실험 결과를 해석할 때 세포 내에 이미 존재하는 이들 핵수용체 단백질의 영향을 고려하여 주의깊게 해석해야 함을 의미한다.

• 한국환경성돌연변이발암원학회지
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• 제24권4호
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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.

• 한국환경보건학회지
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• 제30권3호
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• pp.230-238
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• 2004

The adverse health effects of a number of environment pollutions are related to the formation of free radicals. Induction of antioxidant defensive system in the response to an oxidative attack is an essential element of the cell to survive. CYP2E1 is easily induced by organic solvents and induces continuous formation of reactive oxygen species (ROS). ${\gamma}$-Glutamyltranspeptidase (${\gamma}$GT) plays an important role in glutathione metabolism and xenobiotic detoxification. To evaluate the characteristic of oxidative stress which induces GGT expression and to understand human antioxidant defensive response against oxidative stress induced by CYP2E1, we studied regulation of ${\gamma}$GT enzyme expression in response to various oxidative stresses in human HepG2 cells. The ${\gamma}$GT activity was not modified after exposure of acute oxidative stress inducing agents (ferric nitrilotriacetate, cumene hydroperoxide, ADP-Fe, O-tetradecanoylphorbol-13-acetate, tumor necrosis factor-alpha). To induce continuous exposure of cells to ROS, HepG2 cells were transfected by human CYP2E1 gene transiently. The CYP2E1 activity was verified with chlorzoxazone hydroxylation. Transfection of CYP2E1 showed continuous 60% increase in intracellular ROS and 240 % increase in microsomal ROS. CYP2E1 overexpressing cells showed increased ${\gamma}$GT activity (2.5-fold). The observed enhancement of ${\gamma}$GT activity correlated with a significant increase of ${\gamma}$GT mRNA (2.1-fold). Treatment with antioxidant strongly prevented the increase in ${\gamma}$GT activity. The CYP2E1 overexpression did not modify toxicity index and increased glutathione levels. These results show that continuous exposure of cells to ROS produced by CYP2E1 up-regulates ${\gamma}$GT; This may be one of the adaptive antioxidant responses of cells to oxidative insult. Present study also suggests that the induction of ${\gamma}$GT could be used as a marker of oxidative stress induced by exposure to organic solvents.