Pre-validation of Tissue Specific Micronucleus Assay for Genotoxicity Testing

描述（由申请人提供）：项目摘要/摘要：任何人类使用的新产品的安全性评估都需要进行遗传毒性测试以确保产品不致癌。目前的遗传毒性测定是基于细菌或非人类细胞系统。这种测试很敏感，但特异性很低（假阳性结果率很高）。因此，重要的新化学品（可能是拯救生命的药物）可能会从进一步的开发中被淘汰。也使用动物系统，例如啮齿动物；然而，从2009年开始，欧洲的立法将禁止制造商销售使用动物进行测试的化妆品。鉴于当今的全球经济，这项立法将直接影响到绝大多数美国公司。最后，对于局部应用的皮肤或化妆品材料，利用具有固有代谢活性的系统来确定对皮肤的遗传毒性的测试将是最佳的。本提案的总体目标是开发一种皮肤特异性遗传毒性试验。体外高度分化的皮肤等效组织将用于准确确定局部暴露后的遗传毒性。基于重要的初步结果，这项研究很可能会导致人类体外皮肤特异性微核（INVSSMN）测定，它将取代目前的体外和动物遗传毒性试验。INVSSMN测试将克服目前测试方法的低特异性，避免动物福利问题。I期提案的具体目标是：(1)评估INVSSMN试验对10种已知基因毒素和5种非基因毒性化学物质的检测；(2)对10种已知需要代谢激活才能成为诱变剂的基因毒性化学物质的INVSSMN试验进行评估；(3)研究重建皮肤遗传毒性试验的可重复性；(4)自动化分析和评分。项目说明：对所有人类使用的新产品进行安全评估需要进行基因毒性测试，以确保产品不致癌。目前的方法不具有组织和人体特异性，这导致特异性水平极低，并且从进一步开发中消除了重要物质。我们将利用体外人体重建皮肤模型开发皮肤特异性微核试验，以克服当前测试方法特异性低的问题，避免动物福利问题。

DESCRIPTION (provided by applicant): Project Summary/Abstract: Safety assessment of any new product for human use requires genotoxicity testing to insure that the product is not carcinogenic. Current genotoxicity assays are based on bacterial or non-human cell systems. Such tests are sensitive but give very low specificity (high rate of false positive results). Hence important new chemicals (possibly life-saving drugs) may be eliminated from further development. Animal systems, e.g., rodents, are also used; however, beginning in 2009, legislation in Europe will prevent manufacturers from marketing cosmetics products that have been tested using animals. Given today's global economy, this legislation will directly affect the vast majority of US companies. Finally, for topically applied dermatologic or cosmetic materials, a test which determines genotoxicity to the skin that utilizes a system with inherent metabolic activity would be optimal. The overall goal of this proposal is to develop a skin specific genotoxicity assay. An in vitro highly differentiated skin equivalent tissue will be used to accurately determine the genotoxicity following topical exposure. Based on significant preliminary results, it is likely that this research will result in a human in vitro, skin-specific micronucleus (INVSSMN) assay which will replace current in vitro and animal-based genotoxicity tests. The INVSSMN test will overcome the low levels of specificity of current test methods and avoid animal welfare issues. The specific aims of the Phase I proposal are to: (1) evaluate the INVSSMN assay for a battery of 10 known genotoxins and 5 non-genotoxic chemicals; (2) evaluate INVSSMN assay for a battery of 10 genotoxic chemicals that are known to require metabolic activation to become mutagens; (3) investigate reproducibility of a reconstructed skin genotoxicity test; and (4) automate analysis and scoring. Project Narrative: Safety assessment of all new products for human use requires a genotoxicity testing to insure that product is not carcinogenic. Current methods are not tissue and human specific which results in an extremely low level of specificity and elimination of important substances from further development. We will develop a skin-specific micronucleus assay by utilizing in vitro human reconstructed skin model to overcome low levels of specificity of current test methods and avoid animal welfare issues.