Tetrahydroisoquinoline Antitumor Drugs: Synthesis and Biosynthesis

描述(申请人提供)：本申请的主要重点是研究由四氢异喹啉组成的复杂的、具有生物医学意义的天然产物的全合成和生物合成。将开发的合成化学将用于制备天然物质的类似物，作为生物、生物合成和机械探针。这一建议主要是由假设驱动的，并广泛采用了本实验室开发的新的合成方法来构建此类试剂。该项目的具体目的是研究天然抗肿瘤抗生素和机械激发的合成类似物，包括内毒素743(ET-743)、沙拉霉素、柔红霉素、毒鼠明、来诺霉素和双恶霉素与细胞核酸的相互作用。将探索这些药物的DNA烷基化能力与它们对核酸造成氧化损伤的能力。将继续开发这类抗肿瘤药物成员的合成，目的是利用开发的合成方法来制造新的、毒性较低、更具选择性和更有效的抗肿瘤药物。此外，还将利用合成工具来合成机械探针，用于这些物质与细胞核酸和与细胞核酸结合的蛋白质的相互作用。我们最近发现比奥沙霉素12特异性地在54dCpG34步交叉连接双链DNA。我们建议阐明共价加合物的确切分子结构。这一发现启发了基于四氢异喹啉核心的更简单类似物的新设计概念，该核心可能能够使DNA烷基化和交联，以及潜在地将DNA与DNA结合蛋白交联。这类生物碱的抗增殖活性与这些药物与DNA结合和共价修饰的能力密切相关。这一点在ET-743的情况下尤为明显。提出了从机械上将这些试剂的DNA烷基化和交联化学与其对细胞造成氧化损伤的能力分开的计划。将继续研究ET-743的生物合成，特别是大环硫化物-桥联螺环-四氢异喹啉环体系的后期组装。我们计划应用高通量的基因组测序方法，使用454技术来鉴定来自涡虫外鞘的ET-743生物合成基因簇。生物合成研究的最终目标是对可发酵微生物进行基因工程，以生产临床使用的ET-743。公共卫生相关性：这项应用的目的是利用化学合成工具来研究大自然如何生物合成抗癌药物的分子细节。特别是，该计划将部署新技术，通过微生物宿主的基因工程，在工业实际规模上生产临床相关的抗癌药物ecteinassidin 743(ET-743)。此外，正在开发的化学技术将应用于抗癌新药的设计和合成。

DESCRIPTION (provided by applicant): The primary focus of this application is to study the total synthesis and biosynthesis of complex, biomedically significant natural products constituted of tetrahydroisoquinolines. The synthetic chemistry that will be developed shall be utilized to prepare analogues of the natural substances as biological, biosynthetic and mechanistic probes. This proposal is primarily hypothesis-driven, and extensively employs new synthetic methodologies developed in this laboratory for the construction of such agents. The specific aims of this program are to study the interaction of the natural antitumor antibiotics and mechanistically inspired synthetic analogs, including ecteinascidin 743 (Et-743), saframycin, jorumycin, tetrazomine, lemonomycin and the bioxalomycins with cellular nucleic acids. The DNA-alkylating capacity of these drugs compared with their ability to cause oxidative damage to nucleic acids will be explored. The synthesis of members of this class of antitumor drugs will continue to be developed with the objective of harnessing the synthetic methodology developed to make new, less toxic, more selective and more potent antitumor drugs. In addition, the tools of synthesis will be exploited to synthesize mechanistic probes for the interaction of these substances with cellular nucleic acids and proteins that bind to cellular nucleic acids. We have recently discovered that bioxalomycin 12 specifically cross-links duplex DNA at 54dCpG34 steps. We propose to elucidate the exact molecular structure of the covalent adduct. This finding has inspired new design concepts for simpler analogs based on the tetrahydroisoquinoline core that may be capable of alkylating and cross-linking DNA as well as potentially cross-linking DNA to DNA-binding proteins. The antiproliferative activity of this family of alkaloids is intimately associated with the capacity of these agents to bind to and covalently modify DNA. This is particularly evident in the case of Et-743. Plans are presented to mechanistically separate the DNA alkylation and cross-linking chemistry of these agents from their capacity to inflict oxidative damage on cells. The investigation of the biosynthesis of Et-743 with a particular focus on the late-stage assembly of the macrocyclic sulfide-bridged spiro-tetrahydroisoquinoline ring system will be pursued. We plan to apply high throughput genome sequencing methods using 454 technology to identify the Et-743 biosynthetic gene cluster from Ecteinascidia turbinata. The ultimate goals of the biosynthesis studies are to genetically engineer a fermentable microorganism to produce Et-743 for clinical use. PUBLIC HEALTH RELEVANCE: The purpose of this application is to utilize the tools of chemical synthesis to study the molecular details of how Nature biosynthesizes anti-cancer drugs. In particular, this program will deploy new technologies to produce the clinically relevant anticancer drug ecteinascidin 743 (Et-743) on industrially practical scale through genetic engineering of a microbial host. In addition, the chemical technologies being developed will be applied to the design and synthesis of new anti-cancer drugs.