Function and Regulation of Human Cytochrome P4502S1

人细胞色素P4502S1的功能和调控

• 批准号: 7291643
• 负责人: OLIVER nmn HANKINSON
• 金额: $ 23.63万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-28 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7291643
• 关键词: 5' Flanking Region; Address; Adverse effects; Aflatoxin B1; Antibodies; Antioxidants; Aromatic Hydrocarbons; Aromatic Polycyclic Hydrocarbons; Aryl Hydrocarbon Receptor; Bacteria; Bacterial Artificial Chromosomes; Base Sequence; Benzo(a)pyrene; Biological; CYP1B1 gene; CYP2S1 gene; Carcinogen Metabolism; Carcinogens; Cell Line; Cells; Complement; Cytochrome P450; Cytochromes; Development; Dioxins; Disease; Elements; Environment; Environmental Carcinogens; Enzymes; Epidermis; Epithelial; Epithelium; Family member; Genes; Goals; Human; Hypoxia; Indium; Intestines; Investigation; Knockout Mice; Lung; Mammalian Cell; Mediating; Metabolic Activation; Metabolism; Mus; Naphthalene; Naphthalenes; Nucleic Acid Regulatory Sequences; Organ; Pathway interactions; Pattern; Pharmacologic Substance; Physiology; Play; Poison; Polycyclic Hydrocarbons; Population; Protein Overexpression; Proteins; Regulation; Research Personnel; Respiratory System; Response Elements; Role; Skin; Structure of respiratory epithelium; System; Tissues; Transgenic Mice; Tretinoin; Whole Organism; Xenobiotic Metabolism; Xenobiotics; chemical carcinogen; enzyme substrate; expression vector; gene induction; insight; metabolic abnormality assessment; programs; toxicant

DESCRIPTION (provided by applicant): CYP2S1 is a recently identified human cytochrome P450, expressed extensively in epithelial tissues. We propose that CYP2S1 plays a significant role in the metabolic activation of environmental procarcinogens, and the metabolism of pharmaceuticals and endogenous compounds. The proposal will address this hypothesis and characterize regulation of the enzyme. There are three specific aims: (i) We have expressed human CYP2S1 in bacteria, and demonstrated that it metabolizes several compounds that are toxic and/or carcinogenic to epithelial tissues. We will also over-express the enzyme in mammalian cells. Using these expression systems, we will screen for additional substrates, and also for procarcinogens that are activated to mutagenic (and therefore probably carcinogenic) derivatives by CYP2S1. The Km and Vmax values will be determined for representative compounds, and the metabolites that are formed will be identified. The degree to which CYP2S1 contributes towards the total metabolism of particular substrates in human epithelial tissues will be determined using an inhibitory antibody to the enzyme, (ii) We have shown that CYP2S1 is inducible by dioxin, carcinogenic polycyclic aromatic hydrocarbons (PAHs), and hypoxia. We will investigate whether the potential Xenobiotic Responsive Elements (XREs), or the potential Antioxidant Response Element (ARE) in the 5' flanking region of the human CYP2S1 gene mediate induction by dioxin and/or PAHs, and address the hypothesis that due to the particular nucleotide sequences of the above XREs, the gene responds better to PAHs than to dioxin in certain cells. We will also analyze the mechanism of hypoxic induction of the gene, (iii) We will generate a knockout mouse for Cyp2s1, and then generate a derivative of this mouse containing the human CYP2S1 gene, including its flanking regulatory regions. This "CYP2S1-humanized" mouse will be used to study the metabolism of substrates of human CYP2S1, the biological consequences of this metabolism, and the regulation of the human CYP2S1 gene by xenobiotics and hypoxia, thus complementing and extending specific aims 1 and 2. Our studies may demonstrate important roles for CYP2S1 in the metabolism of carcinogens, Pharmaceuticals and endogenous compounds, and may ultimately provide opportunities for reducing the deleterious effects of environmental carcinogens and the adverse effects of certain Pharmaceuticals in the human population.

描述（由申请人提供）：CYP2S1是最近鉴定出的人类细胞色素P450，在上皮组织中广泛表达。我们提出，CYP2S1在环境促促促促促螺旋体的代谢激活以及药物和内源性化合物的代谢中起着重要作用。该提案将解决这一假设并表征酶的调节。有三个特定的目的：（i）我们在细菌中表达了人CYP2S1，并证明它代谢了几种对上皮组织有毒和/或致癌性的化合物。我们还将过表达哺乳动物细胞中的酶。使用这些表达系统，我们将筛选出其他底物，以及通过CYP2S1激活为诱变（可能以及可能致癌的）衍生物的丙菌素。将针对代表性化合物确定KM和VMAX值，将确定形成的代谢物。 CYP2S1对人上皮组织中特定底物的总代谢的程度将使用酶的抑制性抗体确定，（ii）我们已经表明，CYP2S1可通过二恶英，致癌性多余的芳族芳族芳族氢化氢（PAHS）和过氧而诱导。我们将调查潜在的异种源反应元件（XRES），还是人CYP2S1基因的5'侧面区域中潜在的抗氧化剂反应元件（IS）是否通过二恶英和/或PAHS介导了诱导，并解决了由于基因在某些Xres的特定核苷酸序列而引起的假设，该假设比Xres的特定核苷酸序列响应了。我们还将分析基因缺氧诱导的机制，（iii）我们将生成CYP2S1的基因敲除小鼠，然后生成该小鼠的衍生物，该小鼠含有人CYP2S1基因，包括其侧翼调节区域。这种“ CYP2S1人性化”的小鼠将用于研究人CYP2S1底物的代谢，这种代谢的生物学后果以及对人CYP2S1基因的调节，通过异种生物和缺氧对人类CYP2S1基因的调节，因此可以补充和扩展特定的目的1和2。和内源性化合物，最终可能会提供减少环境致癌物的有害影响以及某些药物对人类人口的不利影响的机会。