NOVEL AUREOLIC ACID TYPE ANTITUMOR AGENTS

新型金黄色酸型抗肿瘤剂

• 批准号: 6360277
• 负责人: Jurgen T Rohr
• 金额: $ 25.46万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6360277
• 关键词: analog; biosynthesis; clinical research; enzyme activity; genetic promoter element; human subject; interferon gamma; mithramycin; osteoclasts; osteopetrosis; oxidoreductase; pathologic bone resorption; polyketide synthase; protooncogene; skeletal pharmacology; transcription factor; transferase

DESCRIPTION: (provided by applicant):Mithramycin (MTM) is an aureolic acid antimicrobial and antitumor agent produced by various Streptomyces species including S. argillaceus, which has been used, e.g., for the treatment of testicular carcinoma. In addition, MTM is unique among anticancer agents in that it also has been used clinically to treat cancer-caused malignant hypercalcemia and Paget's bone disease. However, MTM's bone marrow, hepatic, and renal toxicity limit its widespread clinical use. It is proposed to investigate various aspects of the biosynthesis of the antitumor and osteoclast-inhibiting agent mithramycin in order to develop analogs with increased therapeutic indices, which also may allow the separation of the two principal effects of MTM, (i) on cancer growth and (ii) on osteoclasts. This will lead to novel antitumor agents and/or to therapeutics against osteoporosis and other diseases related to bone growth disorders, and bears the potential for a novel gene therapy concept in future. Combinatorial biosynthetic methods will be used to provide an array of MTM analogs. For this, the biosynthetic pathway to MTM, which is dominated by a type II polyketide synthase (PKS), needs to be further characterized. Especially genes encoding enzymes responsible for the late biosynthetic steps, the post-PKS tailoring enzymes, particularly oxidoreductases and group transferases will be modified Resulting mutant strains will help to determine the series of events within the biosynthetic pathway and will characterize substrates and function of important enzymes in the MTM pathway. This information will be used to design novel compounds with specific activity-increasing functionality. In context with the mechanism of action of MTM on osteoclasts, we want to explore whether MTM derivatives can effect the expression of c-src, a proto-oncogene necessary for the osteoclastic bone resorption, following the novel hypothesis that MTM and its derivatives inhibit osteoclast bone resorption by blocking Sp 1 binding to the promoter region of the c-src proto-oncogene. The following three specific aims will be addressed: (1) To further characterize the biosynthetic pathway of mithramycin and to develop new niithramycin derivatives through selective gene inactivation and product identification. Various group transferases and oxidoreductases will be investigated. In addition, the mtm genes will be recombined with promising deoxysugar biosynthesis, glycosyltransferase and oxygenase encoding genes from other pathways to develop novel niithramycin analogs modified in their saccharide and/or 0-atom pattern. (2) The two oxygenases of the MTM pathway, MtmOII and MtmOIV, will be investigated. The work on MtmOII, an early-acting oxygenase, will help to identify the missing link between the final PKS product and 4-demethylpremithramycinone, the earliest mithramycin precursor documented to date. Tetracyclic niithramycin analogs will be converted into their tricycic and expected more active counterparts by overexpressing oxygenase MtmOIV in the various glycosyltransferase deletion mutants. (3) To assay the binding properties of MTM and its novel analogs to the GC-rich elements in the c-myc and c-src promoters and their ability to prevent Sp 1 binding. Testing the high-affinity c-myc will follow thisand c-src binding compounds for inhibition of gene expression in human cancer cells and for their effects on growth and viability of normal and cancer cells. Finally, promising c-src inhibiting analogs will be analyzed for activity against osteoclastmediated bone resorption.

描述：(申请人提供)：米特拉霉素(MTM)是一种金酸 几种链霉菌生产的抗菌抗肿瘤药物 包括已被用于例如治疗 睾丸癌。此外，MTM在抗癌药物中是独一无二的 它还被用于临床治疗由癌症引起的恶性肿瘤 高钙血症和Paget‘s骨病。然而，MTM的骨髓，肝脏， 肾毒性限制了其在临床上的广泛应用。现建议： 研究抗肿瘤药物生物合成的各个方面 破骨细胞抑制剂米曲霉素，以开发类似物 增加治疗指数，这也可能使两者分离 MTM的主要作用是：(1)促进肿瘤生长；(2)促进破骨细胞生长。这 将导致新的抗肿瘤药物和/或治疗骨质疏松症 和其他与骨骼生长障碍相关的疾病，并具有潜在的 为未来一种新的基因治疗概念。组合生物合成方法 将用于提供MTM模拟数组。为此，生物合成的 MTM的途径，其由II型聚酮合成酶(PKS)主导， 需要进一步确定其特征。尤其是编码酶的基因 负责后期的生物合成步骤，后PKS剪裁酶， 特别是氧化还原酶和基团转移酶将被修饰，从而 突变株将有助于确定 生物合成途径及其将表征底物和功能的重要 MTM途径中的酶。这些信息将被用来设计小说 具有特定活性增加功能的化合物。在与 MTM对破骨细胞的作用机制，我们想要探讨MTM是否 衍生物可以影响c-src的表达，c-src是 破骨细胞性骨吸收，遵循新的假说MTM和 其衍生物通过阻断Sp-1结合抑制破骨细胞骨吸收 原癌基因c-src启动子区域。 将实现以下三个具体目标： (1)进一步确定米曲霉素的生物合成途径，并 通过选择性基因失活和基因工程技术开发新的硝酸拉霉素衍生物 产品标识。各种基团转移酶和氧化还原酶将 调查过了。此外，MTM基因将与有希望的基因重组 脱氧糖的生物合成、糖基转移酶和加氧酶编码基因 开发新型硝酸霉素类似物的其他途径 糖和/或0原子模式。 (2)MTM途径的两种加氧酶MtmOII和MtmOIV将被 调查过了。对一种早期作用的加氧酶MtmOII的研究将有助于 确定最终的PKS产品和 4-去甲基普雷米松，最早的米特拉霉素前体 约会。四环尼特拉霉素类似物将转化为它们的三环化合物 通过在细胞中过表达加氧酶MtmOIV来期待更活跃的对应物 各种糖基转移酶缺失突变体。 (3)测定MTM及其新的富含GC类似物的结合特性 C-myc和c-src启动子中的元件及其预防Sp-1的能力 有约束力的。测试高亲和力的c-myc将遵循这一点和c-src结合 抑制人癌细胞基因表达的化合物及其作用 对正常细胞和癌细胞的生长和活力的影响。最后，前景看好 C-src抑制类似物的活性将被分析 破骨细胞介导的骨吸收。