• Title/Summary/Keyword: cytochrome P450 2E1

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Effects of Bisphenol and Octylphenol on TM3 Cell : Expression of Cytochrome P450scc and Estrogen Receptor $\alpha$ mRNA (Bisphenol과 Octylphenol이 TM3 세포에 미치는 영향: Cytochrome P450scc와 Estrogen Receptor $\alpha$ 유전자의 발현)

  • 이호준;김묘경;강희규;김동훈;한성원;고덕성
    • Development and Reproduction
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    • v.4 no.2
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    • pp.215-220
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    • 2000
  • Most of endocrine disrupters (EDs) have been reported to exhibit estrogenic or anti-androgenic activity and thereby may disrupt reproductive development in human or wildlife. This study was performed to investigate the effects of estrogen (E$_2$), bisphenol (BP) and octylphenol (OP) on the mouse Leydig cell line (TM3). TM3 originated from testis of 11~13-daly-old BALB/c nu/+ mice was cultured in DMEM supplemented with 10% FBS alone or medium with estrogen (E$_2$), bisphenol (BP) and octylphenol (OP; 1 pM, 1 nM, 1 $\mu$M, 1 mM, respectively) for 48 hours. After culture, total cell number and viability were assessed by heamocyto-meter and trypan blue stain. Expression of cytochrome P450scc (CYPscc) mRNA whose product is involved in steroid hormone biosynthesis and estrogen receptor $\alpha$(ER $\alpha$) mRNA were detected by RT-PCR. As a result, treatment of TM3 with E$_2$, BP and OP(1 mM, respectively) significantly decreased the viability but not all of groups as high as 1 $\mu$M. Exposure of TM3 to OP significantly reduced the total cell number but not E$_2$ or BP. The expression of CYPscc mRNA was slightly reduced in BP (1 nM, 1 $\mu$M) and significantly decreased in OP (1 nM, 1 $\mu$M) treated TM3, except E$_2$ group. But the expression of ER $\alpha$ mRNA was sightly increased in all treated groups. In conclusion, BP and OP (high concentration) might inhibit steroidogenesis by decreasing the CYPscc mRNA expression in the mouse testis. These results suggest that BP and OP might impair spermatogenesis and subsequently disturb testicular function.

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Inhibition of Carcinogen-Activating Cytochrome P450 Enzymes by Xenobiotic Chemicals in Relation to Antimutagenicity and Anticarcinogenicity

  • Shimada, Tsutomu
    • Toxicological Research
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    • v.33 no.2
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    • pp.79-96
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    • 2017
  • A variety of xenobiotic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), aryl- and heterocyclic amines and tobacco related nitrosamines, are ubiquitous environmental carcinogens and are required to be activated to chemically reactive metabolites by xenobiotic-metabolizing enzymes, including cytochrome P450 (P450 or CYP), in order to initiate cell transformation. Of various human P450 enzymes determined to date, CYP1A1, 1A2, 1B1, 2A13, 2A6, 2E1, and 3A4 are reported to play critical roles in the bioactivation of these carcinogenic chemicals. In vivo studies have shown that disruption of Cyp1b1 and Cyp2a5 genes in mice resulted in suppression of tumor formation caused by 7,12-dimethylbenz[a]anthracene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, respectively. In addition, specific inhibitors for CYP1 and 2A enzymes are able to suppress tumor formation caused by several carcinogens in experimental animals in vivo, when these inhibitors are applied before or just after the administration of carcinogens. In this review, we describe recent progress, including our own studies done during past decade, on the nature of inhibitors of human CYP1 and CYP2A enzymes that have been shown to activate carcinogenic PAHs and tobacco-related nitrosamines, respectively, in humans. The inhibitors considered here include a variety of carcinogenic and/or non-carcinogenic PAHs and acethylenic PAHs, many flavonoid derivatives, derivatives of naphthalene, phenanthrene, biphenyl, and pyrene and chemopreventive organoselenium compounds, such as benzyl selenocyanate and benzyl selenocyanate; o-XSC, 1,2-, 1,3-, and 1,4-phenylenebis(methylene)selenocyanate.

EFFECT OF CIS-ELEMENT ON THE REGULATION Of TROUT LIVER CYTOCHROME P450IAl GENE EXPRESSION

  • Hwang, Jung E.;Sheen, Yhun Y.
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1996.04a
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    • pp.188-188
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    • 1996
  • In order to gain insight into the mechanism of the regulation of cytochrome P450IAl by arylhydrocarbon, the 5'-flanking region of a trout CYP450IAl 5'flanking DNA was cloned into pCAT-basic vector and it was transfected into Hepa-1 cells. 3MC treatment to hepa Ⅰ cells transfected with fish CYP450IAl-CAT construct results in mRNA increased by 2.81 fold when it was compared with that of control This increase of mRNA was decreased by concomitantly treated flavonoids such as morin. The levels of CAT mRNA that was treated with morin was 29.2-58.0% of 3MC stimulated CAT mRNA. Further investigation to find out if there are DRE, XRE or negative regulatory cis element in CYP450IA1 gene was undertaken. Results of the deletion study of 5'flanking DNA of trout P450IA indicate the existance of the negative(-1600 ~ -1300). CAT mRNA was about two-fold higher in deleted trout CYP450IAl-CAT construct transfected cells compared to the wi Id type trout CYP450IAl-CAT construct transfected cells. And The stimulatory effect of 3MC was no longer observed in col Is containing deleted CAT construct. [Supported by grants from the Korean Ministry of Education]

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Scavenging Activity of Reactive Oxygen Species and Inhibitory Effect of Cytochrome P450 from Circium japonicum Extract (대계 추출물의 할성산소 소거능 및 Cytochrome P450 효소 저해효과)

  • Kim, Hyuck;Yi, Hyo-Seung;Park, Won-Hwan;Moon, Jin-Young
    • The Korea Journal of Herbology
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    • v.22 no.1
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    • pp.53-61
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    • 2007
  • Objectives: Our previous studies have clearly demonstrated that the scavenging activity of reactive oxygen species (ROS), protective effect of lipid peroxidation (LPO), and inhibition of cytochrome P450 isozymes (CYPs) from the Circium japonicum aqua-acupuncture solution (CJAS). But, Circium japonicum water extracted solution (CJWS) was weakly reported in cardiovascular diseases such as oxidative stress-mediated atherosclerosis or its value evaluated. Methods: CJWS was assessed to determine the mechanism of its scavenging activity of ROS and inhibitory effect of CYP 2E1. Results: CJWS exhibited a concentration-dependent scavenger of DPPH and superoxide anions radicals using different assay systems. In addition, CJWS showed dose-dependent free radical scavenging activity, including hydroxyl radicals, peroxynitrite, and nitric oxide. The CJWS was also found to be effective in protecting rat liver homogenate against LPO. Futhermore, the CJWS showed significant inhibition of CYP 2E1 induced by pyrazol in a rat liver microsome. Conclusion : ROS and CYPs may play a role in several diseases, such as cardiovascular disease and heart failure. Our study demonstrated that the CJWS has excellent scavenging activity of ROS. Hence, it is worthwhile to investigate the potential effectiveness of CJWS in preventing oxidative stress-mediated cardiovascular diseases.

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Inhibition of Cytochrome P450 by Propolis in Human Liver Microsomes

  • Ryu, Chang Seon;Oh, Soo Jin;Oh, Jung Min;Lee, Ji-Yoon;Lee, Sang Yoon;Chae, Jung-woo;Kwon, Kwang-il;Kim, Sang Kyum
    • 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.

Water Extract of Ash Tree (Fraxinus rhynchophylla) Leaves Protects against Paracetamol-Induced Oxidative Damages in Mice

  • Jeon, Jeong-Ryae
    • Food Science and Biotechnology
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    • v.15 no.4
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    • pp.612-616
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    • 2006
  • The protective effect of water extract of ash tree leaves (ALE) against oxidative damages was investigated in paracetamol-induced BALB/c mice. Biochemical analysis of anti-oxidative enzymes, immunoblot analyses of hepatic cytochrome P450 2El (CYP2E1), and the gene expression of tumor necrosis factor (TNF-${\alpha}$) were examined to determine the extract's protective effect and its possible mechanisms. BALB/c mice were divided into three groups: normal, paracetamol-administered, and ALE-pretreated groups. A single dose of paracetamol led to a marked increase in lipid peroxidation as measured by malondialdehyde (MDA). This was associated with a significant reduction in the hepatic antioxidant system, e.g., glutathione (GSH). Paracetamol administration also significantly elevated the expression of CYP2E1, according to immunoblot analysis, and of TNF-${\alpha}$ mRNA in liver. However, ALE pretreatment prior to the administration of paracetamol significantly decreased hepatic MDA levels. ALE restored hepatic glutathione and catalase levels and suppressed the expression of CYP2E1 and TNF-${\alpha}$ observed in inflammatory tissues. Moreover, ALE restored mitochondrial ATP content depleted by the drug administration. These results show that the extract of ash tree leaves protects against paracetamol-induced oxidative damages by blocking oxidative stress and CYP2E1-mediated paracetamol bioactivation.

Bioactivation of Aromatic Amines by Human CYP2W1, An Orphan Cytochrome P450 Enzyme

  • Eun, Chang-Yong;Han, Song-Hee;Lim, Young-Ran;Park, Hyoung-Goo;Han, Jung-Soo;Cho, Kyoung-Sang;Chun, Young-Jin;Kim, Dong-Hak
    • 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.

Functional RsaI/PstI Polymorphism in Cytochrome P450 2E1 Contributes to Bladder Cancer Susceptibility: Evidence from a Meta-analysis

  • Deng, Xiao-Dong;Gao, Qin;Zhang, Bo;Zhang, Li-Xia;Zhang, Wei;Er, Zhe-Er Mu;Xie, Ying;Ma, Ying;Liu, Yun
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.12
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    • pp.4977-4982
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    • 2014
  • Background: Cytochrome P450 2E1 (CYP2E1) might be involved in the development of bladder cancer. However, previous studies of any association between CYP2E1 RsaI/PstI polymorphism and bladder cancer risk have yielded conflicting results. In this study, we performed a more precise estimation of the relationship by a meta-analysis based on the currently available evidence from the literature. Method: To assess the effect of CYP2E1 RsaI/PstI polymorphism on bladder cancer susceptibility, a meta-analysis of 6 available studies with 1,510 cases and 1,560 controls were performed through Feb 2014. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to estimate the strength of association for CYP2E1 RsaI/PstI polymorphism under different genetic models. Results: When available studies were pooled into the meta-analysis, we found that the C1C2 and C2C2 genotypes of CYP2E1 RsaI/PstI polymorphism significantly decreased bladder cancer risk under different genetic models (heterozygote: OR=0.766, 95%CI=0.613-0.957, $P_{OR}$=0.019; homozygote: OR=0.51, 95%CI=0.303-0.858, $P_{OR}$=0.011; dominant: OR=0.733, 95%CI=0.593-0.905, $P_{OR}$=0.004; recessive: OR=0.565, 95%CI=0.337-0.947, $P_{OR}$=0.030). Subgroup analysis indicated that C2C2 genotype was significantly associated with decreased bladder cancer risk under the homozygote genetic model in Caucasians. There was no evidence of heterogeneity or publication bias. Conclusions: The current meta-analysis suggested that the CYP2E1 RsaI/PstI polymorphism might be associated with bladder cancer susceptibility, especially in Caucasians. Further studies are needed to validate the above conclusion.

In vitro Assessment of Cytochrome P450 Inhibition by Red Ginseng Ginsenosides (홍삼 Ginsenoside의 Cytochrome P450 저해 활성 평가)

  • Ryu, Chang Seon;Shin, Jang Hyun;Shin, Byoung Chan;Sim, Jae Han;Yang, Hyeon Dong;Lee, Sung Woo;Kim, Bong-Hee
    • YAKHAK HOEJI
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    • v.59 no.2
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    • pp.49-54
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    • 2015
  • In the present study we evaluated comparative herb-drug interaction potential of red ginseng total powder, ginsenoside Rg1, and Rb1 by inhibition of CYP isoforms including CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4 using pooled human liver microsomes (HLMs). As measured by liquid chromatography-electrospray ionization tandem mass spectrometry, red ginseng total powder inhibited significantly activities of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and testosterone 6-beta hydroxylation by CYP3A4, but the $IC_{50}$ values were higher than $556{\mu}g/ml$. Activities of CYP2B6, CYP2C9, CYP2D6 and CYP3A4 were inhibited by ginsenoside Rb1. Also, activities of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6 and testosterone 6-beta hydroxylation by CYP3A4 were inhibited by ginsenoside Rg1. The $IC_{50}$ values of ginsenoside Rb1 and Rg1 were higher than $200{\mu}g/ml$. Based on $IC_{50}$ values against CYP isoforms, ginsenosides-drug interactions by CYP inhibition may be very low in clinical situations.

chemopreventive Effects of 2-(Allylthio) pyrazine

  • Kim, Nak-Doo;Kim, Sang-Geon
    • Archives of Pharmacal Research
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    • v.22 no.2
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    • pp.99-107
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    • 1999
  • A series of organosulfur compounds were synthesized with the aim of developing chemopreventive compounds active against hepatotoxicity and chemical carcinogesis. 2-(Allylthio) prazine (2-AP) was effective in inhibiting cytochrome P450 2E1-mediated catalytic activities and protein expression, and in inducing microsomal epoxide hydrolase and major glutathione S-transferases. 2-AP reduced the hepatotoxicity caused by toxicant sand elevated cellular GSH content. Development of skin tumors, pulmonary adenoma and aberrant crypt foci in colon by various chemical carcinogens was inhibited by 2-AP pretreatment. Anticarcinogenic effects of 2-AP at the stage of initiation of tumors were also observed in the aflatoxin B1 ($AFB_1$)-induced three-step medium-term hepatocarcinogenesis model. Reduction of $AFB_1$-DNA adduct by 2-AP appeared to result from the decreased formation of $AFB_1$-8,9-epoxide via suppression of cytochrome P450, while induction of GST 2-AP increases the excretion of glutathione-conjugated $AFB_1$ . 2-AP was a radioprotective agent effective against the lethal dose of total body irradiation and reduced radiation-induced injury in association with the elevation of detoxifying gene expression. 2-AP produces reactive oxygen species in vivo, which is not mediated with the thiol-dependent production of oxidants and that NF-KB activation is not involved in the induction of the detoxifying enzymes. the mechanism of chemoprotection by 2-AP may involve inhibition of the P450-mediated metabolic activation of chemical carcinogens and enhancement of electrophilic detoxification through induction of phase II detoxification enzymes which would facilitate the clearance of activated metabolites through conjugation reaction.

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