INTERACTIONS OF ANTITUMOR AGENTS WITH NUCLEIC ACIDS

该项目将探索与以下方面相关的生物物理特性 选择的抗肿瘤剂（及其结构上的）相互作用 相关类似物）与核酸。 在此过程中， 研究，努力将集中在相关的物理- 这些药物-DNA相互作用的化学性质与它们的生物学性质有关。 作为拓扑异构酶II抑制剂的有效性。 实验将 旨在解决有关物理和/或化学 决定拓扑异构酶II抑制的性质，无论这些 性质与这些化合物的DNA结合有关， 最后，它们引发拓扑异构酶II的机制 抑制作用 几种主要的抗肿瘤药物的拟议机制 药物，包括m-AMSA、VP-16、VM-26、阿霉素、柔红霉素和 米托蒽醌介导的抗肿瘤活性是通过抑制 拓扑异构酶II活性。 关于实际机制的资料 药物发挥这种类型的抑制作用的方式是有限的。 然而，这些化合物与DNA相互作用的能力确实 这似乎是一个基本的要求， 拓扑异构酶II发生。 我们已经设计，合成， 表征了一系列修饰的苯胺基吖啶类化合物， 连接到N-苯基侧链和吖啶环上，用作 用于检查药物所需结构要求的探针- 诱导拓扑异构酶II抑制发生。 此系列吖啶 类似物提供了一个独特的机会， 与三元复合物相关的物理化学性质 形成和评估化学取代基类型和 在介导拓扑异构酶II活性上的位置。 的活动 推测这些化合物存在于三元络合物的形成中 拓扑异构酶II-DNA和药物之间的关系我们将探测 和功能特性的三元复合物，使用各种 方法包括抗肿瘤剂的光亲和交联， DNA（和/或拓扑异构酶II）。 3-叠氮基-m-AMSA将提供 检测拓扑异构酶-DNA-药物三元复合物的理想探针 并提供深入了解m-AMSA发挥其 生物效应。 在光解之前，该化合物已被 证明以与亲本m-AMSA相同的方式结合DNA。 在光解时，叠氮基转化为反应性氮烯， 在原位形成共价连接。 我们的实验室最近 观察到3-叠氮基-m-AMSA的非共价加成正如 有效地引发拓扑异构酶II抑制，作为母体m- AMSA;表明其作为检查 m-AMSA的机械性质。 利用这个探测器，我们将尝试 获得对三元络合物的整体几何结构的洞察（即， 药物相对于拓扑异构酶II和DNA的位置）。 在 此外，我们的研究将检查结合性能， 拓扑异构酶Ⅱ-DNA的拓扑特异性 拓扑异构酶II抑制剂存在和不存在下的相互作用 抗生素 这些对几种选定的抗肿瘤药物（类似物）的研究将 让我们深入了解这些化合物 发挥其强大的生物效应和药物的性质-DNA 配合物，从而导致更合理的设计新的抗肿瘤药物， 剂.

This project will explore the biophysical properties associated with the interactions of selected antitumor agents (and their structurally relevant analogs) with nucleic acids. During the course of this research, efforts will be focused towards correlating the physical- chemical nature of these drug-DNA interactions with their biological effectiveness as topoisomerase II inhibitors. Experiments will be designed to address questions concerning the physical and/or chemical properties which dictate topoisomerase II inhibition, whether these properties are related to the DNA binding of these compounds, and finally, the mechanism(s) by which they elicit topoisomerase II inhibition. The proposed mechanism by which several of the leading antitumor agents, including m-AMSA, VP-16, VM-26, adriamycin, daunorubicin, and mitoxantrone mediate antitumor activity is through the inhibition of topoisomerase II activity. Information concerning the actual mechanism by which the drugs exert this type of inhibition effect is limited. However, the ability for these compounds to interact with DNA does appear to be an essential requirement for inhibition of the topoisomerase II to occur. We have designed, synthesized, and characterized a series of anilinoacridine compounds with modifications to both the N-phenyl side chain and to the acridine ring to use as probes for examining the structural requirements necessary for drug- induced topoisomerase II inhibition to occur. This series of acridine analogs provide a unique opportunity for examining and characterizing both the physical-chemical properties associated with ternary complex formation and evaluating the influence of chemical substituent type and position on mediating topoisomerase II activity. The activities of these compounds is presumed to reside in formation of a ternary complex between the topoisomerase II-DNA and drug. We will probe the structural and functional properties of this ternary complex, using a variety of methods including photoaffinity crosslinking of the antitumor agent to the DNA (and/or topoisomerase II). The 3-azido-m-AMSA will provide an ideal probe for examining the topoisomerase-DNA-drug ternary complex and provide insight into the mechanism(s) by which m-AMSA exerts its biological effects. Prior to photolysis, this compound has been demonstrated to bind DNA in a manner identical to the parent m-AMSA. Upon photolysis, the azido is converted to the reactive nitrene which forms a covalent attachment in situ. Our laboratory has recently observed that the noncovalent addition of 3-azido-m-AMSA was just as effective in eliciting topoisomerase II inhibition as the parent m- AMSA; indicative of its effectiveness as a probe for examining the mechanistic properties of m-AMSA. With this probe, we will attempt to obtain insight into the overall geometry of the ternary complex (i.e., the location of drug with respect to topoisomerase II and DNA). In addition, our studies will examine the binding properties and topological specificities associated with topoisomerase II-DNA interactions in the absence and presence of topoisomerase II inhibiting antibiotics. These studies on several selected antitumor agents (analogs) will provide insight into our overall understanding of how these compounds exert their potent biological effects and the nature of the drug-DNA complexes, thus leading to a more rational design of novel antitumor agents.