真菌次级代谢产物茯苓酸的结构修饰改造与抗肿瘤活性研究

Fungi secondary metabolites have been discovered as important source of drug lead compounds which have new structure and unique activities. Pachymic acid is a lanostane triterpenoid isolated from Poria cocos (Schw.) Wolf, which shows potential anticancer activity. However, poor soluble, mild anticancer activity and unclear mechanism limit its application. At present, no paper has reported the modification of pachymic acid and its structure-activity relationship. This project is focused on the structure modification of pachymic acid, using the principles of medicinal chemistry, including functional group derivatization, skeleton change, bioisosterism, pharmacophore hybridization and prodrug design, to increase the antitumor activity and improve the bioavailability. Then, the derivatives of pachymic acid will be evaluated for their cytotoxicity in vitro to summarize the preliminary structure-activity relationship. Next, one or two highly potential compounds will be evaluated for the metabolic kinetics and in vivo anticancer activity. Meanwhile, the antitumor mechanisms of pachymic acid and its derivatives will be investigated by apoptosis and autophagy, and targets will be confirmated through gene chip technology to provide theoretical basis for the development of high efficiency and low toxicity of antitumor drugs.

真菌次级代谢产物具有结构新颖、活性特别等特点，是重要的药物先导化合物来源。茯苓酸是从多孔菌科真菌茯苓中提取分离得到的羊毛甾烷型四环三萜，具有一定的抗肿瘤活性。但是，茯苓酸水溶性较差、抗肿瘤活性不强及作用机制尚不明确等问题限制了其进一步应用。目前，还未见茯苓酸的结构修饰改造及构效关系的研究报道。本研究以茯苓酸为先导化合物，拟对其结构进行修饰改造和衍生化，主要利用药物化学领域的官能团衍生化、骨架改变、生物电子等排、药效团杂合和前药设计等原理和方法，期望增加该类化合物的抗肿瘤活性，提高其生物利用度；并对所得衍生物进行体外抗肿瘤活性研究，总结该类化合物的初步构效关系；寻找到1－2个高活性茯苓酸衍生物，开展代谢动力学研究，同时进行体内抗肿瘤实验；从凋亡和自噬等途径探讨茯苓酸及其衍生物的抗肿瘤作用机制，并通过基因芯片技术研究作用靶点，为开发高效、低毒的抗肿瘤药物提供理论基础。

以茯苓酸为先导化合物，通过官能团衍生化、骨架改变、药效团杂合和前药设计等方法，合成了四类共计50余个结构新颖的衍生物。测试目标产物的体外抗肿瘤活性（HepG2和HSC-2细胞株），发现部分衍生物的抗肿瘤活性强于母体化合物，得到活性最强的先导化合物A17。进一步研究衍生物A17的抗肿瘤分子机制，包括周期阻滞、凋亡、自噬、信号通路等。动物实验结果显示，衍生物A17具有较强的体内抗肿瘤活性。初步的基因组学研究表明，A-17可能影响CEA cell adhesion molecule 6和keratin 2等的表达。通过本项目实施，发表SCI论文4篇，申请发明专利3项。