Detoxification of Electrophilic Chemical Threat Agents by Nucleophilic Scavengers

亲核清除剂对亲电化学威胁剂的解毒

• 批准号: 7665443
• 负责人: Michael C MacLeod
• 金额: $ 54.62万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-30 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7665443
• 关键词: 2-chloroethyl ethyl sulfide; 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; Antidotes; Apoptosis; Apoptotic; Area; Biological Markers; Bulla; Carcinogens; Cell Death; Cell Nucleus; Cells; Chemical Agents; Chemicals; DNA Adducts; Data; Drug Metabolic Detoxication; Edema; Ellagic Acid; Engineering; Enhancers; Enzymes; Epidemiologic Studies; Epidemiology; Event; Fibrosis; Genes; Genetic; Genetic Predisposition to Disease; Genotype; Glutathione; Glutathione S-Transferase; Goals; Histopathology; Human; Human Resources; In Vitro; Individual; Infiltration; Inflammation; Knowledge; Lead; Left; Lung; Lymphocyte; Measurement; Measures; Mechlorethamine; Medical; Melphalan; Methodology; Methods; Modeling; Mus; Mustard; Mustard Agent; Mustard Gas; Mutagenesis; Mutation; Necrosis; Nucleic Acids; Organism; Population; Predisposition; Prevention; Process; Protective Agents; Proteins; Reaction; Reporter; Reporter Genes; Research; Research Personnel; Role; Sampling; Signal Pathway; Site; Skin; Structure of parenchyma of lung; Sulfur; Testing; Therapeutic Intervention; Tissue Model; Tissues; Toxic effect; Transgenic Organisms; Translations; Validation; Variant; Work; adduct; airway epithelium; carcinogenesis; chemical carcinogen; chemical carcinogenesis; chemical reaction; cytotoxicity; design; dimethyl sulfate; emergency service responder; human tissue; in vivo; macromolecule; mouse model; multidisciplinary; novel; prevent; programs; repaired; research study; response; toxicant

DESCRIPTION (provided by applicant): One class of chemical threat agents for which medical countermeasures must be developed, the sulfur and nitrogen mustards (SNMs), exert their toxic effects through chemical reactions that involve an electrophilic intermediate. In this respect they are similar to many widely studied chemical carcinogens, and therefore strategies that have been used to detoxify these carcinogens should be applicable to the mustard agents. The primary strategies to be developed in this Project will block the ability of SNMs to form DNA adducts in exposed cells. We will use a combined in vitro/in vivo approach to determine the efficacy of two groups of potential protective agents: nucleophilic scavenging agents and agents that enhance endogenous conjugation reactions, particularly the addition of glutathione to the electrophile by the glutathione-S transferase (GST) enzymes. Two classes of nucleophilic scavenger will be tested: the dithiopurines (DTP) and ellagic acid. Both of these have been shown to completely detoxify the carcinogen BPDE. DTP has also been shown to detoxify melphalan, a nitrogen mustard, and in preliminary studies we have demonstrated facile reaction of DTP with a sulfur mustard, 2-chloroethyl ethyl sulfide. We will use cultured human cells derived from skin and lung to first test these protective compounds against SNMs, with cytotoxicity and mutagenesis as the primary endpoints. The most efficacious compounds will then be tested in two engineered human tissue models, one representing skin, the other representing airway epithelia, with toxic histopathology as the primary endpoint. Finally, the effective compounds will be tested in vivo in mice, using either topical treatment with subsequent analysis of skin, or intratracheal instillation with subsequent analysis of lung tissue. Toxicity endpoints in the mouse tissues will include histopathology (pyknotic/apoptotic nuclei, edema, vesication, infiltration, fibrosis) and induction of mutations in reporter genes carried in the transgenic mutation-reporter mice. These experiments will test the best scavenger, the best GSH/GST enhancer, and a combination of the two compounds. We will also test the sensitivity of human lymphocytes from 300 individuals to SNMs, and correlate the sensitivity with genotypes measured at several GST genetic loci that are polymorphic in the human population. Other biomarkers of exposure, including generalized protein adducts and a specific protein adduct will be analyzed where appropriate. Relevance: We expect to validate a strategy to efficiently detoxify electrophilic chemical threat agents, such as the SNMs and dimethyl sulfate. This will allow us to begin to formulate novel antidotes that could be used to protect personnel responding to an incident involving SNMs, and to stabilize exposed individuals against further damage. In addition, we will obtain data that indicates whether or not individuals with variants of a particular class of genes, the GSTs, are more susceptible to the effects of SNM toxicants.

描述(申请人提供)：一类必须开发医学对策的化学威胁物质，硫和氮芥末(SNM)，通过涉及亲电中间体的化学反应发挥其毒性作用。在这方面，它们与许多被广泛研究的化学致癌物相似，因此，已经用于解毒这些致癌物的策略应该适用于芥子剂。本项目将开发的主要策略将阻止SNM在暴露的细胞中形成DNA加合物的能力。我们将使用体外和体内相结合的方法来确定两组潜在的保护剂的有效性：亲核清除剂和促进内源性结合反应的试剂，特别是谷胱甘肽-S转移酶将谷胱甘肽添加到凝胶中。将测试两类亲核清除剂：二硫嘌呤(DTP)和鞣花酸。这两种药物都已被证明可以完全解毒致癌物质BPDE。DTP还被证明可以解毒氮芥菜马法兰，在初步研究中，我们已经证明了DTP与硫芥菜2-氯乙基硫化物的简单反应。我们将使用来自皮肤和肺的培养的人类细胞首先测试这些保护化合物对SNMS的保护作用，并以细胞毒性和诱变为主要终点。然后，最有效的化合物将在两个工程人体组织模型中进行测试，一个代表皮肤，另一个代表呼吸道上皮，以毒性组织病理学为主要终点。最后，这些有效化合物将在小鼠体内进行测试，使用局部治疗和随后的皮肤分析，或者气管内滴注和随后的肺组织分析。小鼠组织中的毒性终点将包括组织病理学(固缩/凋亡核、水肿、水泡、渗透、纤维化)和诱导转基因突变报告鼠携带的报告基因的突变。这些实验将测试最好的清除剂，最好的GSH/GST增强剂，以及两种化合物的组合。我们还将测试300个人的淋巴细胞对SNM的敏感性，并将敏感性与几个在人类群体中具有多态的GST遗传基因座测量的基因类型相关联。其他暴露的生物标志物，包括一般的蛋白质加合物和特定的蛋白质加合物，将在适当的情况下进行分析。相关性：我们希望验证一种有效解毒亲电化学威胁物质的策略，如SNM和硫酸二甲酯。这将使我们能够开始制定新的解毒剂，可以用来保护应对涉及SNM的事件的人员，并稳定受影响的个人免受进一步损害。此外，我们将获得数据，表明具有特定基因类别GST变异的个体是否更容易受到SNM毒物的影响。