Chemical and Biological Mechanisms of Leinamycin

描述（由申请人提供）：从历史上看，天然产品已被证明是抗癌药物的丰富来源。最近的一项综述估计，在这一医学领域中，74%的临床使用的药物是天然产物或衍生自天然产物先导化合物。这一统计数据表明，重要的是癌症社区继续研究新的抗癌药物从天然来源分离。本提案中所描述的工作旨在表征DNA损伤天然产物雷那霉素的化学和生物学机制。莱那霉素对人癌细胞系显示出非常有效的活性（例如，对HeLa细胞的IC 50为0.014 ng/mL -这意味着IC 50为27 nM），目前正在Kyowa Hakko Kogyo Pharmaceuticals开发作为潜在的抗癌药物。双链体DNA暴露于雷那霉素导致脱嘌呤位点（AP位点）的快速“爆发”产生。此外，与莱那霉素的反应将攻击性硫醇残基转化为过硫化物（RSSH）物质，其有可能在细胞中引起氧化应激。莱那霉素不产生DNA交联或双链断裂，但显示出与临床使用的药物相当的生物活性。因此，不寻常的DNA损伤特性的雷那霉素可能代表了一个新的生化途径，以有效的抗癌活性。本提案中描述的实验旨在将莱那霉素的独特生化特性与其对癌细胞系的有效活性联系起来。我们将检验这一假设，即莱纳霉素的能力，同时产生一个AP网站的爆发沿着氧化应激的帐户非常强大的生物活性。 工作分为以下五个具体目标：1。验证AP位点的快速生成是莱那霉素杀伤癌细胞特性的核心的假设。2.探讨双链DNA中来霉素-鸟嘌呤加合物超快速脱氨的化学基础。3.检验莱那霉素在人类癌细胞系中引起氧化应激的假设。4.探索生理相关条件下莱那霉素产生活性氧的化学机制。5.表征细胞对来那霉素的反应。

DESCRIPTION (provided by applicant): Historically, natural products have proven a rich source of anticancer drugs. A recent review estimated that 74% of the clinically used drugs in this field of medicine are natural products or are derived from natural product lead compounds. This statistic suggests that it is important for the cancer community to continue studies of novel anticancer agents isolated from natural sources. The work described in this proposal is designed to characterize the chemical and biological mechanisms of the antineoplastic, DNA- damaging natural product leinamycin. Leinamycin displays very potent activity against human cancer cell lines (e.g. IC50 of 0.014 ng/mL - this translates to an IC50 of 27 nM - against HeLa cells) and is currently in development as a potential anticancer agent at Kyowa Hakko Kogyo Pharmaceuticals. Exposure of duplex DNA to leinamycin leads to production of a rapid "burst" of apurinic sites (AP sites). In addition, reaction with leinamycin converts the attacking thiol residue into a persulfide (RSSH) species that has the potential to cause oxidative stress in cells. Leinamycin does not generate DNA-crosslinks or double-strand breaks, but displays biological activity comparable to clinically used agents that do. Thus, the unusual DNA-damaging properties of leinamycin may represent a new biochemical route to potent anticancer activity. Experiments described in this proposal are designed to relate leinamycin's unique biochemical properties to its potent activity against cancer cell lines. We will test the hypothesis that leinamycin's ability to simultaneously generate a burst of AP sites along with oxidative stress account for its very potent biological activity. The work is divided into the following five Specific Aims: 1. Test the Hypothesis That the Rapid Generation of AP Sites Is Central to Leinamycin's Cancer Cell Killing Properties. 2. Explore the Chemical Basis for the Exceedingly Rapid Depurination of the Leinamycin-Guanine Adduct in Duplex DNA. 3. Test the Hypothesis That Leinamycin Causes Oxidative Stress In Human Cancer Cell Lines. 4. Explore the Chemical Mechanisms by Which Leinamycin Generates Reactive Oxygen Species Under Physiologically Relevant Conditions. 5. Characterize Cellular Responses to Leinamycin.