低温真菌来源α-吡喃酮类分子的抗肿瘤活性及作用机制研究

Cancer is one of the major diseases with serious harm to human health. Looking for fungal secondary metabolites with anti-tumor activity is one of important ways to find anti-tumor lead compounds. The project is based on our early research on the aspects of the structure and pharmacological activity of the secondary metabolites from the psychrotolerant fungi and the discovery of the α-pyrone class secondary metabolites Rasfonin and its derivatives with significant cytotoxic activity from a psychrotolerant fungus (Doratomyces sp.). In vitro anti-tumor activity evaluation, chemical screening guided by LC/UV/MS as well as various separation techniques are applied to largely enrich Rasfonin and to discover other anti-tumor α-pyrones from the amplification fermentation extract of this fungus. And then, we will explore the structure-activity relationships (SAR) by comparison and analysis of the cytotoxic activity of Rasfonin, its synthetic derivatives and other isolated natural analogues to obtain the target compounds for further research on their anti-tumor mechanism and the rapid ADME evaluation in vitro, thereby providing the basis for the discovery of anti-tumor lead compounds.

癌症是严重危害人类健康的重大疾病之一。从真菌资源中寻找抗肿瘤活性次生代谢产物是发现抗肿瘤先导化合物的重要途径之一。本项目基于申请人在低温真菌次生代谢产物的结构和药理活性方面的研究积累，以从一株矛束霉属（Doratomyces sp.）低温真菌中发现的具有显著体外抑瘤活性的α-吡喃酮类次生代谢产物Rasfonin及其同系物为导向，结合体外抑瘤活性评价以及LC/UV/MS指导的化学筛选，应用多种分离技术从产生菌的放大发酵提取物中大量富集Rasfonin，并快速、高效地发现其它结构类似的抗肿瘤活性成分。在此基础上，对Rasfonin进行结构修饰，制备系列衍生物，并与分离的其它类似物的抑瘤活性比较、分析，探索构效关系，获得值得深入研究的目标化合物，对其开展初步抗肿瘤作用机制研究与体外快速ADME评价，为抗肿瘤先导化合物的发现提供依据。

从西藏低温真菌Doratomyces sp.中分到的次级代谢产物Rasfonin，有显著的抗肿瘤活性。由于报道的Rasfonin的全合成的产率极低，无法对其进行抗肿瘤作用机理研究。因此，我们首先通过优化发酵条件，将Rasfonin在Doratomyces sp.中的产率大幅提高（Rasfonin约占总提取物的2.5%），再通过放大发酵，大量制备得到3.5克纯品Rasfonin和另外6个具有抗肿瘤活性的α-吡喃酮类天然化合物；并采用化学方法对Rasfonin进行结构修饰改造，制备得到29个衍生物，活性测试后发现所有改造后的化合物均具有抗肿瘤活性，其中2个活性改造产物与Rasfonin相比活性提高2–5倍。此外，我们还重点对Rasfonin的抗肿瘤作用机制进行了较为系统的研究，首次发现Rasfonin能引起癌细胞发生自噬、坏死和凋亡现象，明确了Rasfonin降低Ras蛋白的活性与其降低Sos1的表达有关，还首次发现Akt可以与糖酵解途径相互协调来调节Rasfonin引起的细胞自噬和凋亡。