Novel Aureolic Acid-Type Antitumor Agents

性状（由申请方提供）：金油酸型抗癌药，如光神霉素（MTM）或色霉素（CMM），是具有独特作用模式的强效抗癌药。它们通过交联富含GC的DNA来抑制癌细胞的生长，从而关闭针对各种原癌基因（包括c-myc和c-src）的特异性蛋白（Sp）依赖性途径，后者与这些药物发现的独特的低钙活性相关。尤其是MTM是重要的，并已成为一种流行的生化工具来研究SP依赖的信号转导途径，但由于其毒副作用很少被用作抗癌剂，除了治疗其他化疗难治性的肿瘤高钙血症。然而，MTM最近被确定为治疗神经系统疾病、关节炎和血液系统疾病的潜在先导药物。所有这些新的应用只需要非常小的，毒性较低的药物浓度，尽管在这些情况下的作用模式仍然不清楚。MTM的生物合成在本研究项目的前一个资助期间进行了深入研究，因此进行组合生物合成的努力揭示了各种生物合成中间体和新的MTM类似物。这些类似物中的两种，MTM SK和MTM SDK，显示出比MTM本身更好的抗癌活性特征，治疗指数大大提高。这些新药值得进一步研究。在以前的生物合成研究中发现了生物合成有趣和有趣的关键酶，需要进一步研究，特别是加氧酶MtmOIV，酮还原酶MtmW，糖基转移酶MtmGIV，MtmGIII，MtmGII，MtmGI和其他早期作用的聚酮合酶后剪裁加氧酶和还原酶。我们的目标是了解这些酶在MTM生物合成中的作用和机制，并优化它们用于新型MTM衍生物的工程设计。计划（a）进一步研究MTM和CMM途径的不清楚的生物合成步骤和机制，并应用组合生物合成产生新的MTM类似物，（B）分析有趣的加氧酶和还原酶，（c）研究和改善糖基转移酶的底物特异性，（d）在体外和体内研究MTM SK、MTM SDK和项目期间开发的其他有前途的MTM类似物。 公共卫生相关性：这项工作的目的是开发和改进新一代的金油酸型天然产物类似物，其毒性显着降低，主要用作抗癌药物，但也可用作治疗神经系统疾病，关节炎和血液系统疾病的药物。为了通过组合生物合成生产这些微调药物，将探索包括关键酶在内的生物合成机制的深入研究。

DESCRIPTION (provided by applicant): Aureolic acid-type anticancer agents, such as mithramycin (MTM) or chromomycin (CMM), are potent anticancer drugs with a unique mode-of-action. They inhibit the growth of cancer cells by cross-linking GC-rich DNA thereby shutting down specificity-protein (Sp)-dependent pathways towards various proto-oncogenes including c-myc and c-src, the latter being associated with the unique hypocalcemic activity found for these drugs. Particularly, MTM is important, and has become a popular biochemical tool to study Sp-dependent signal transduction pathways, but due to its toxic side effects is rarely used as anticancer agent, except for the treatment of tumor hypercalcemia refractory to other chemotherapy. However, MTM was recently identified as a potential lead drug against neurological diseases, arthritis, and for the treatment of hematologic disorders. All these new applications require only very small, less toxic concentrations of the drug, although the mode-of- action in these contexts remains obscure. MTM's biosynthesis has been studied intensely during the previous funding period of this research project, and consequently pursued combinatorial biosynthetic efforts revealed various biosynthetic intermediates and new MTM-analogues. Two of these analogues, MTM SK and MTM SDK, showed a much better anticancer activity profile with a greatly improved therapeutic index than MTM itself. These new drugs deserve further investigations. During the previous biosynthetic studies biosynthetic intriguing and interesting key enzymes were discovered, which need to be further investigated, particularly oxygenase MtmOIV, Ketoreductase MtmW, glycosyltransferases MtmGIV, MtmGIII, MtmGII, MtmGI, and other, early acting post-polyketide synthase tailoring oxygenases and reductases. The goal is to understand the role and mechanisms of these enzymes in the MTM biosynthesis, and to optimize them for the engineering of novel MTM derivatives. It is planned to (a) further investigate unclear biosynthetic steps and mechanisms of the MTM and CMM pathways and to generate new MTM analogues applying combinatorial biosynthesis, (b) to analyze intriguing oxygenases and reductases, (c) to investigate and improve the substrate specificity of glycosyltransferases, (d) to study in vitro and in vivo MTM SK, MTM SDK and other promising MTM analogues developed during the project. PUBLIC HEALTH RELEVANCE: The proposed work aims to develop and refine a new generation of aureolic acid type natural product analogues with significantly diminished toxicity that will be useful mainly as anticancer drugs, but also as drugs to treat neurological diseases, arthritis and hematologic disorders. To enable the production of these fine-tuned drugs through combinatorial biosynthesis, in-depth research of the biosynthetic machinery including key enzymes will be explored.