【作者】 董月辉；

【导师】 刘兆鹏；

【作者基本信息】 山东大学 ， 药物化学， 2008， 硕士

【摘要】 肿瘤是严重威胁人类生命的常见病和多发病,其死亡率仅次于心血管疾病而列居第二。肿瘤细胞具有快速增殖能力,其有丝分裂过程频繁且细胞周期明显短于正常细胞。微管是细胞有丝分裂过程中重要的细胞骨架之一,为动态不稳定结构,在细胞有丝分裂过程中具有促使姐妹染色单体分离的重要作用。这一重要作用使微管成为抗肿瘤治疗的重要靶点。抗有丝分裂药物在肿瘤治疗中发挥着重要的作用。它们主要通过破坏微管蛋白/微管之间的动态循环（聚合和解聚）来治疗各种实体肿瘤。根据对微管作用的不同将药物分为两类:抑制微管蛋白聚合的药物,如长春碱类;稳定微管的药物,如紫杉烷类和埃坡霉素类。抑制微管蛋白聚合的药物通过与β微管蛋白结合使细胞分裂停止于G₂/M期;稳定微管的药物有两个不同的结合位点:秋水仙碱位点和长春碱位点,但作用机制相似,即可逆地与β微管蛋白结合形成“药物-蛋白”复合物,阻止其他蛋白单体的继续添加而抑制微管的聚合,同时还通过诱导微管的解聚抑制纺锤体的形成,使细胞的有丝分裂停止于M期。紫杉醇与多西他赛是最早用于治疗实体瘤的微管蛋白抑制剂,但由于耐药性的出现,使其应用受到局限。近年来,小分子微管蛋白抑制剂研究方面取得了很大的进展。其中,磺胺类药物ABT-751可以口服给药,生物利用度高。它通过与秋水仙碱结合位点β微管蛋白结合,抑制微管的聚合,现已进行临床研究。另一方面,秋水仙碱、鬼臼毒素、Combretastatin A-4（CA-4）等天然抗肿瘤药物分子中的多酚醚类结构是抑制微管蛋白聚合的主要药效团之一。基于片断的药物设计（Fragment based drug design）是近年来发展、成熟起来的寻找先导化合物的有效方法。本文基于微管蛋白秋水仙碱结合腔的特点,以微管蛋白抑制剂ABT-751分子中的苯磺酰胺结构片段和作用于微管蛋白同一靶点的天然产物鬼臼毒素等分子中的多酚醚结构片段为基础,利用基于片断的药物设计方法并结合计算机辅助药物设计,设计结构新颖的五元环苯并磺内酰胺类小分子微管蛋白抑制剂。合成反应分别以苯磺酰氯和1,2-亚甲二氧基苯为原料,通过磺化、氨解、亲核加成及环合等反应得到目标产物。通过优化环合反应条件,开辟了合成3位单取代苯并磺内酰胺的新途径,并合成了两个系列共23个全新结构的化合物。所合成化合物的化学结构由IR、MS以及¹H-NMR光谱分析确证。将设计合成的化合物进行了初步的抑制微管蛋白聚合、细胞生长抑制活性筛选。结果显示,化合物虽然对微管蛋白聚合及细胞生长有一定的抑制作用,但是活性不高。这可能是由以下原因造成的:首先,由于目标化合物溶解性不是很好,导致测试溶液中有效浓度的降低而使得活性丧失;其次,目标化合物为消旋体,计算机对接结果显示S型与秋水仙碱结合腔匹配性较好,R型则匹配较差。总之,我们以微管蛋白为靶点,采用基于片段的药物设计新理念,以微管蛋白抑制剂ABT-751分子中的苯磺酰胺结构片段和作用于微管蛋白同一靶点的天然产物鬼臼毒素等分子中的多酚醚结构片段为基础,结合计算机辅助药物设计,设计并合成两个系列全新结构的五元环3位单取代苯并磺内酰胺衍生物,并对部分化合物进行了体外微管蛋白聚合抑制和细胞生长抑制活性筛选。这为进一步设计新型微管蛋白抑制剂奠定了基础。更多还原

【Abstract】 Cancer is a common and frequently-occurring disease that threatens the human life seriously and causes mortality only second to cardiovascular vessel diseases. Tumor cells proliferate rapidly, and the cell cycle is obviously shorter than normal cell. The tubulin/microtubule system is an integral component of the cytoskeleton. Microtubules are highly dynamic structures that play a critical role in orchestrating the separation and segregation of chromosomes during mitosis. This makes microtubules highly valued as anticancer drug targets.Antimitotic agents that target the dynamic equilibrium between the microtubule polymer and tubulin heterodimers are key components of chemotherapeutic regimens for various solid tumors. These agents can be divided into two major classes based on their effect on microtubule polymerization and the mass of microtubule polymers: those that inhibit polymerization, such as the vinca alkaloids and those that stabilize microtubules, such as the taxanes and epothilones. The agents that inhibit tubulin polymerization bind toβ-tubulin, and make cells in G₂/M arrest. The microtubule-stabilizing agents bind to two classes of sites on tubulin: the colchicine, and Vinca domains. But their mechanism of action are similar. They bind toβ-tubulin to form "drug-proteinum" complex reversibly, so they can prevent other protein to bind, resulting in inhibition of tubulin polymerization. At the same time they inhibit the formation of spindles through inducing the depolymerization of microtubule. These actions make cells in M arrest. The taxanes paclitaxel （Taxol） and docetaxel （Taxotere） were the first antimicrotubule agents approved for use in solid tumors, but their usefulness is often limited by development of drug resistance. In recent years, small-molecule antimitotic agents have been a focus in the development of effective anticancer drugs. Among them, ABT-751 is an orally bioavailable sulfonamide that binds to the colchicine binding site on beta-tubulin and inhibits microtubule polymerization and currently undergoing clinical evaluation for the treatment of many kinds of tumors.On the other hand, the polyphenolic pharmacophore are widely existed in the molecules of many antimitotic agents like colchicines, podophyllotoxin, Combretastatin A4, among others.Fragment-based drug design has become an important and powerful tool for the discovery and optimization of new drug leads. Base on the binding models of colchicine site in tubulin, making use of the fragment-based drug design approach, with the help of computer-assisted drug design, we designed a series of five-membered benzosultams in order to discover novel antimitotic agents. These compounds have the key features that combine the sulfonamide fragment and the important polyphenolic pharmacophore in one molecule.We have developed a novel method for the synthesis of 3-monosubstitued five-membered benzosultams. Based on our new method, 23 compounds with different substituens at A-ring or C-ring have been synthesized. All of them have been characterized by IR, MS and ¹H-NMR spectral analysis.Some of the synthesized benzosultam analogues have been analyzed for tubulin destabilization activity using commercial reagents with fluorescence detection. The preliminary results showed that these analogs appears capable of inhibiting tubulin polymerization to some extent, but the levels of activity measured in these assays does not appear to demonstrate meaningful activity that can be expected to significantly impact cancer cell proliferation. Some of the synthesized benzosultams have also been analyzed for growth inhibition activity using breast cancer cells. The results indicate these compounds have much lower growth inhibition activity than podophyllotoxin or colchicine. The poor solubility in water and the racemic properties may attribute, in part, to the low activities in the bioassay tests.In summary, based on the sulfonamide fragment and the polyphenolic pharmacophore, with the aid of computer-assisted drug design, we have designed and synthesized novel benzosultams as antimitotic agents. The tubulin destabilization activity and the cell growth inhibition activity have been also studied. Our researches may provide useful information for further design of small-molecule antimitotic drugs.更多还原