Function and Regulation of Human Cytochrome P4502S1

人细胞色素P4502S1的功能和调控

• 批准号: 7476561
• 负责人: OLIVER nmn HANKINSON
• 金额: $ 24.44万
• 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/7476561
• 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是最近鉴定的人细胞色素P450，广泛表达于上皮组织中。我们认为CYP2S1在环境致癌物的代谢激活以及药物和内源性化合物的代谢中发挥着重要作用。该提案将解决这一假设并描述酶的调节特征。有三个具体目标：（i）我们在细菌中表达了人类 CYP2S1，并证明它可以代谢几种对上皮组织有毒和/或致癌的化合物。我们还将在哺乳动物细胞中过度表达该酶。使用这些表达系统，我们将筛选其他底物，以及被 CYP2S1 激活为诱变（因此可能致癌）衍生物的原致癌物。将确定代表性化合物的 Km 和 Vmax 值，并鉴定形成的代谢物。 CYP2S1 对人类上皮组织中特定底物总代谢的贡献程度将使用该酶的抑制性抗体来确定，(ii) 我们已经证明 CYP2S1 可以被二恶英、致癌多环芳烃 (PAH) 诱导，并且缺氧。我们将研究人类 CYP2S1 基因 5' 侧翼区域中潜在的异生素反应元件 (XRE) 或潜在的抗氧化反应元件 (ARE) 是否介导二恶英和/或多环芳烃的诱导，并提出以下假设：根据上述 XRE 的特定核苷酸序列，该基因在某些细胞中对 PAH 的反应比对二恶英的反应更好。我们还将分析该基因的缺氧诱导机制，（iii）我们将生成 Cyp2s1 敲除小鼠，然后生成该小鼠的衍生品，该小鼠含有人类 CYP2S1 基因，包括其侧翼调节区。这种“CYP2S1人源化”小鼠将用于研究人类CYP2S1底物的代谢、这种代谢的生物学后果，以及异生素和缺氧对人类CYP2S1基因的调节，从而补充和扩展特定目标1和2。我们的研究可能证明 CYP2S1 在致癌物、药物和内源性化合物代谢中的重要作用，并可能最终为减少环境的有害影响提供机会。致癌物以及某些药物对人群的不利影响。