靶向上皮间质转化（EMT）的新型抗乳腺癌转移先导物发现及其作用机制研究

Breast cancer is the first leading cause of death in women with cancer, and most of them were dead because of distant spread of cancer cells. Although it is the most vicious aspect in breast cancer, but the effective strategies to control this malignant process still lack. Epithelial-mesenchymal transition (EMT) is a key contributor to the invasion and metastasis of epithelial-derived cancers. This important process was initially recognized during several critical stages of embryonic development and has more recently been implicated in promoting carcinoma invasion and metastasis, and also EMT is an ideal target of anti-metastatic agents. In previous studies, we found that several lignanoids extracted from Saururus chinensis (Lour.) Baillon exhibited anti-metastatic properties in vitro and also in vivo. Furthermore, it was demonstrated that one of these lignanoids, SC-0721 inhibited expression of Slug and Vimentin, which are important biomarkers in EMT process. Upon these evidences, we here hypothesize that lignanoids extracted from plants of Saururaceae suppress distant spread of breast cancers by modulating Epithelial-mesenchymal transition of cancer cells. The specific aim of current program is finding leading compounds from plants of Saururaceae and elucidating the underlying mechanisms of these leading compounds. To test these hypotheses, we will: (1)extract lignanoids from Saururus chinensis (Lour.) Baillon and Houttuynia cordata Thunberg which have tight relationship will be isolated by bioactivity-guided fractionation, and get 3-5 candidate compounds; (2)evaluate the anti-metastatic properties of these candidates in vitro an also in vivo, and find the leading compounds; (3) analyze the mechanisms of anti-metastatic activities of the leading compounds. These investigations will provide a foundation for development of new drugs to prevent distant spread of breast cancer in humans.

乳腺癌是女性癌症死亡的首要原因，其中绝大多数患者死于肿瘤的远处转移，但目前缺乏有效治疗措施。上皮间质转化（EMT）指具有极性的上皮细胞转换成为具有移行能力的间质细胞，获得侵袭迁移能力的过程，是恶性肿瘤远处转移的始动因素。前期研究发现，三白草中木脂素类成分具有一定体内、体外抗转移作用。机制研究显示，逆转EMT 可能是其作用机制之一。因此，本研究拟在前期工作基础上，选择亲缘关系较近的三白草科植物- - 三白草和鱼腥草，从中寻找活性更强、具有EMT 逆转作用的抗转移先导物。首先，我们将以体外抗转移和EMT 逆转活性为导向，梳理三白草和鱼腥草木脂素成分的抗转移活性，初步确定3-5 个候选先导物；其次，采用多种体内、外模型验证其活性，确定1-2 个以EMT 为靶点的抗转移先导物；最后，我们还将从EMT 执行分子、参与EMT的转录因子及信号转导分子的行为入手，探索其机制，为新型机制的抗转移药物创制奠定基础

乳腺癌是女性癌症死亡的首要原因，其中绝大多数患者死于肿瘤的远处转移，但目前缺乏有效治疗措施。上皮间质转化（EMT）是恶性肿瘤远处转移的始动因素。前期研究表明三白草木脂素类化合物具有一定抗转移作用，逆转EMT是其可能机制。因此，本研究拟在此基础上，从三白草和鱼腥草中寻找活性更强、具有EMT逆转作用的抗转移先导物，为新型作用机制的抗转移药物创制奠定基础。.化学方面，我们应用各种化学和色谱方法对氯仿和正丁醇两个有效部位进行了系统分离，从三白草科中的三白草和鱼腥草中总计完成了黄酮类、木脂素类以及生物碱在内的数十个化合物的提取分离以及收集工作。.活性筛选方面，我们采用乳腺癌细胞的体外迁移、侵袭和增殖实验，对分离得到的化合物进行活性筛选，确定化合物Saucerneol D（化合物9，CH9）具有较强的抗增殖活性；化合物manassantin B（MB）具有将强的抗血管生成作用以及化合物istanbulin A（ISTA）具有较强的抗转移活性。.药效学研究方面，本研究对上述三个个化合物的的抗肿瘤活性、抗血管生成作用以及抗转移活性进行了系统研究。结果发现CH9对体外培养的两株乳腺癌细胞增殖的抑制作用呈现出浓度和时间依赖性，对细胞独立生存能力也有较显著的抑制作用。化合物MB对内皮细胞体外小管形成具有较强的抑制作用；而化合物ISTA具有良好的乳腺癌细胞粘附、迁移、侵袭功能。 .机制研究方面，CH9的抗肿瘤作用与Src信号通路有关，可能是通过下调磷酸化的Src蛋白进而影响其下游相关信号蛋白的表达。MB的抗血管生成作用则与内皮细胞内MMP-9表达下调相关。ISTA则可下调EGF所介导的上皮间质转化。.本项目完成了几种三白草植物中化学成分的系统分离与抗肿瘤活性研究，并对其中活性较好的化合物CH9、MB、ISTA的药效进行了系统研究，并深入探讨了这些化合物的作用机理，为新型抗肿瘤转移药物的创制奠定了基础。