三种植物中基于雄激素受体抑制的抗前列腺癌成分的发现及作用机制研究

Androgen receptor (AR) signaling is crucial for the genesis and survival of prostate cancer, the aberrant activation of which also plays a pivotal role in the development, aggression, and metastasis of castration-resistant prostate cancer (CRPC). Therefore, AR serves readily as a key target in prostate cancer treatment. In the preliminary study, we have discovered that extracts of Caesalpinia millettii, C. cucullata, and Litsea garrettii exhibited significant AR inhibiting activity, and at the same time inhibited the proliferation of several prostate cancer cell lines. Furthermore, the homoisoflavonoids isolated from C. millettii impair translocation of AR from cytoplasm to nucleus, repressed the transcriptional activity of AR, caused cell cycle arrest, and induced apoptosis on prostate cancer cells. Based on the above results, the aims of the present project are listed as follows: i) To separate the extracts of the above three plants under the guidance of AR inhibiting assay and rapidly obtain the bioactive metabolites and analogs. ii) To assay and analyze the AR inhibiting activity and anti-prostate cancer activity of the active compounds obtained, find out the most potent one, and draw the structure-activity relationship of them. iii) To test the anti-prostate cancer activity of the active compounds in vitro and in vivo, to investigate their effects on the mRNA and protein expression level of key enzymes and coactivators of the AR signaling pathway, and to clarify their michanism of action on cell functions such as proliferation, cell cycle, and apopotosis. The results of this project will make basis for the discovery of new anti-prostate cancer drugs.

雄激素受体(AR)信号通路与前列腺癌的发生和存活密切相关，其异常活化在去势抵抗性前列腺癌(CRPC)的发展、恶化和转移中更是发挥了关键作用，因此AR是重要的抗前列腺癌药物靶点。前期发现小叶云实、见血飞和滇南木姜子提取物可显著抑制AR受体的功能，并抑制前列腺癌细胞的增殖，进一步从小叶云实中获得的高异黄酮类化合物可抑制AR受体的核转位和转录激活功能，并阻滞前列腺癌细胞周期和诱导细胞凋亡。本项目拟在前期的基础上，继续以AR抑制活性为指导，对这三种植物进行深入发掘，阐明其抗前列腺癌的物质基础。全面比较所得化合物的AR抑制活性和抗前列腺癌活性，获得强活性的目标分子并总结其构效关系。开展活性化合物抗前列腺癌和AR抑制的作用机制研究，探索其对AR信号通路关键酶、辅助调节因子和细胞因子在基因和蛋白水平的影响，阐明其AR抑制活性与阻滞肿瘤细胞周期和诱导细胞凋亡的关系，为新型抗前列腺癌药物的发现奠定基础。

本项目完成了小叶云实(Caesalpinia millettii)、见血飞(Caesalpinia cucullata)、滇南木姜子(Litsea garrettii)、潺槁木姜子(Litsea glutinosa)、大叶樟(Cinnamomum parthenoxylon)、树菠萝(Artocarpus heterophyllus)、飞扬草(Euphorbia hirta)等7种植物中活性成分的分离和结构鉴定，共获得各类化合物117个，采用NMR和MS等波谱学技术鉴定了其结构，其中包括新化合物20个，筛选发现了具有较强抗肿瘤活性的化合物多个。采用多株前列腺癌细胞株，重点对高异黄酮类化合物、二萜类化合物、异戊烯基黄酮和多酚类化合物、木脂素类化合物等进行了系统了前列腺癌细胞增殖抑制活性筛选和评价，初步总结了其构效关系。对活性化合物A5和A6抗前列腺癌的机制进行了研究，发现该类化合物可通过抑制AR受体由胞质向胞核的转位和转录激活作用，降低AR的功能，抑制cyclin D的表达，诱导p21的表达，使肿瘤细胞阻滞在G0/G1期，并能诱导细胞凋亡。上述研究工作的完成，对阐明这几种植物的活性成分和新型抗前列腺癌药物的发现具有重要意义。