BIO-ENGINEERING OF COMPOUNDS ACTIVE AGAINST MDR CANCER

有效对抗耐多药癌症的化合物的生物工程

• 批准号: 6765788
• 负责人: Nigel D PRIESTLEY
• 金额: $ 31.61万
• 依托单位: UNIVERSITY OF MONTANA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6765788
• 关键词: P glycoprotein; SDS polyacrylamide gel electrophoresis; Streptomyces; antineoplastic antibiotics; antineoplastics; drug design /synthesis /production; drug resistance; enzyme mechanism; gene expression; mass spectrometry; microorganism metabolism; multidrug resistance; neoplasm /cancer pharmacology; nuclear magnetic resonance spectroscopy; polymerase chain reaction; western blottings

DESCRIPTION (provided by applicant): Multiple drug resistance is becoming a major threat to public health. We are facing a need for both new biologically active compounds and for new methods of making such compounds. Streptomyces produce the majority of antibiotics that are made by bacteria and study of such antibiotic biosynthesis pathways is a basic prerequisite to developing new methods of antibiotic production. The unusual polyketide, nonactin, produced by Streptomyces griseus, is an inhibitor of the P 170-glycoprotein efflux pump found in multiple drug resistant cancer cells. Nonactin is also an ionophore active against Gram positive bacteria, mycobacteria, and fungi. Nonactin is an achiral compound; a tetramer made up from both enantiomers of a precursor nonactic acid. The organism has two mirror image biosynthesis pathways, one for each of the precursor enantiomers. Of particular interest are the late stages of nonactin biosynthesis wherein the complete macrocycle is assembled l as these steps can be manipulated to generate natural product- synthetic compound hybrid analogs of nonactin. The fundamental and applied biochemistry of the highly unusual nonactin biosynthesis system will be studied by: (1) Analysis of the (+)- and (-)-nonactate synthase enzymes, two enzymes that catalyze the same chemical reaction, yet upon different enantiomers of the substrate. (2) Analysis of the ATP-dependent formation of nonactin from dimeric nonactate precursors catalyzed by the enzyme NonL. The process is a unique example of a biological Coupe du Roi synthesis where an achiral molecule is made by the condensation of two homochiral precursors. (3) Analysis of NonR, the enzyme product of the nonactin resistance gene. NonR is likely a serine esterase that renders nonactin inactive. This is a study of a fundamental antibiotic resistance mechanism. We hypothesize that NonR, and a second likely esterase NonD, act together to recycle nonactin and thereby control nonactin synthesis levels. (4) Study of in vivo and in vitro systems derived from the basic biochemistry of the late steps of nonactin biosynthesis to produce a number of natural product-synthetic compound hybrid antibiotics. The biological and chemical properties of the new compounds will be evaluated.

描述（由申请人提供）：多重耐药性正在成为公众健康的主要威胁。我们面临着对新的生物活性化合物和制备此类化合物的新方法的需求。链霉菌产生大多数由细菌产生的抗生素，对此类抗生素生物合成途径的研究是开发抗生素生产新方法的基本先决条件。灰色链霉菌产生的不寻常的聚酮化合物 nonactin 是多种耐药癌细胞中发现的 P 170 糖蛋白外排泵的抑制剂。 Nonactin 也是一种离子载体，具有抗革兰氏阳性菌、分枝杆菌和真菌的活性。 Nonactin 是一种非手性化合物；由前体九乙酸的两种对映体组成的四聚体。该生物体有两条镜像生物合成途径，每一种对应前体对映体。特别令人感兴趣的是非肌动蛋白生物合成的后期阶段，其中组装了完整的大环，因为可以操纵这些步骤来产生非肌动蛋白的天然产物-合成化合物混合类似物。将通过以下方式研究极不寻常的非肌动蛋白生物合成系统的基础和应用生物化学：（1）分析（+）-和（-）-九肌酸合酶，这两种酶催化相同的化学反应，但底物的对映异构体不同。 (2) 分析由 NonL 酶催化的二聚体九乙酸前体中 ATP 依赖性非肌动蛋白的形成。该过程是生物 Coupe du Roi 合成的独特例子，其中非手性分子是通过两个纯手性前体缩合而制成的。 (3)nonR，nonactin抗性基因的酶产物的分析。 NonR 可能是一种丝氨酸酯酶，可使 nonactin 失活。这是对基本抗生素耐药机制的研究。我们假设 NonR 和第二种可能的酯酶 NonD 共同作用以回收非肌动蛋白，从而控制非肌动蛋白的合成水平。 （4）从nonactin生物合成后期的基础生物化学衍生的体内和体外系统研究，以生产多种天然产物-合成复合杂合抗生素。新化合物的生物和化学性质将被评估。