Biosynthesis of the Leinamycin Family of Natural Products: Mechanistic Studies and Chemoenzymatic Analog Synthesis

项目摘要/摘要 在现代社会，化疗一直是癌症治疗的核心，而且在未来几年内仍将如此 可预见的未来。在这方面，历史上使用最多的是破坏DNA的化合物，原因是 相对于正常、健康的细胞，癌细胞的生长和增殖速度更快。然而，这些 治疗通常会引起偏离目标的效应和耐药性的产生。因此，可以破坏的化合物 一种选择性的癌细胞DNA，其机制与目前的临床治疗相辅相成 为这两个问题提供解决方案。天然产物雷诺霉素(LNM)是一种破坏DNA的化合物 这只会在硫醇激活时产生DNA损伤效应，并具有抗肿瘤的纳摩尔活性。 对临床用药有抵抗力的细胞。LNM E1是一种经过工程设计的LNM模拟产品，在通过反应激活时 氧物种(ROS)通过与LNM垂直的机制发挥其抗肿瘤活性。一个单一的脚手架 可以通过两种互补的方式为DNA损伤做准备是这组化合物所独有的，并设置了 为进一步优化LNM支架的抗癌活性奠定了基础。LNM的生物合成起源 在链霉菌中一直是一个密集的研究领域，许多生物合成步骤已经被阐明 并导致了涉及前所未有的化学步骤的发现。这个项目的长期目标是 利用对LNM生物合成的机械学理解的力量来改变遗传生产 用于生产具有改进的治疗特性的类似物的生物体。这项建议包含两个目的：(一) 研究关键生物合成步骤的机制和(Ii)获得两种LNM的合理设计的类似物 和LNM E1回答有关化合物生物活性的具体问题。的中心假说 这一建议是可以通过合理的调整和提高LNM化合物的稳定性和有效性 设计。这一假设是合理的，因为大自然有能力产生一系列LNM型化合物，这 都是本文提出的结构改革的灵感来源。本次申请的结果将是 对LNM生物合成和获得新的LNM类似物的关键步骤之一的机械理解 这可以用来回答有关LNM DNA损伤和抗癌活性的关键问题。这些发现 可以应用于合理的生物合成操作的长期目标，以产生靶向的结构性LNM 用于进一步抗癌开发的类似物。

PROJECT SUMMARY/ABSTRACT Chemotherapy has been the centerpiece of cancer treatment in modern society, and will remain so for the foreseeable future. DNA-damaging compounds have seen the most use historically in this regard, due to cancer cells’ increased rates of growth and proliferation relative to normal, healthy cells. However, these treatments often cause off-target effects and resistance development. Therefore, compounds that can damage cancer cell DNA in a selective fashion and with a mechanism complementary to current clinical treatments offer solutions to both of these issues. The natural product leinamycin (LNM) is a DNA-damaging compound that only elicits its DNA-damaging effects upon activation by thiols, and has nanomolar activity against tumor cells resistant to clinically utilized drugs. LNM E1 is an engineered LNM analog that upon activation by reactive oxygen species (ROS) exerts its antitumor activity via a mechanism orthogonal to LNM. A single scaffold that can be primed for DNA damage in two complementary ways is unique to this set of compounds, and sets the stage for further optimization of the LNM scaffold in terms of anticancer activity. The biosynthetic origin of LNM in Streptomyces has been an area of intense study, and many of the biosynthetic steps have been elucidated and led to discoveries involving unprecedented chemical steps. The long-term goals of this project are to harness the power of a mechanistic understanding of LNM biosynthesis to genetically alter producing organisms for production of analogs with improved therapeutic properties. This proposal contains two aims: (i) investigate the mechanism of a key biosynthetic step and (ii) access rationally-designed analogs of both LNM and LNM E1 to answer specific questions about the compounds’ biological activities. The central hypothesis of this proposal is that LNM compounds can be tuned and improved in both stability and potency through rational design. This hypothesis is rationalized by Nature’s ability to produce an array of LNM-type compounds, which have served as the inspiration for the structural changes proposed herein. The outcomes of this application will be a mechanistic understanding of one of the key steps of LNM biosynthesis and access to novel LNM analogs that can be used to answer key questions about LNM DNA-damaging and anticancer activity. These findings can be applied to the long-term goal of rational biosynthetic manipulation to produce targeted structural LNM analogs for further anticancer development.