特异性抑制胶质瘤干细胞活性三萜的定向挖掘、结构修饰与作用机制研究

胶质瘤是最常见的恶性脑肿瘤，恶性程度极高，具侵袭、转移和复发性强的特点。胶质瘤干细胞(GSCs)具有自我更新、无限增殖和多向分化潜能，是胶质瘤恶性表型和术后复发的“根源”。靶向GSCs治疗，可最大程度地根治和防止肿瘤复发和转移。我们前期获得2个特异性抑制GSCs的天然小分子Euphol和3-Epilupeol，能显著抑制GSCs克隆形成和细胞增殖，诱导细胞凋亡，降低GSCs标志物CD44的阳性表达率。本项目拟以活性三萜为先导结构，通过活性与LC-MS联用相结合，从锁定的活性组分中，定向挖掘结构类似的三萜，研究结构和活性特点；以合理药物设计为指导，以高含量活性成分为前体，设计合成甘遂烷型和羽扇豆烷型三萜衍生物，结合活性测定，从中筛选出选择性抑制GSCs活性最好的化合物向开发抗肿瘤药物方向前进；分析GSCs对特定结构具有特异应答的生物学特性和抗GSCs的机制，为胶质瘤治疗提供新的治疗策略和思路

Glioblastoma multiform (GBM), a common subtype malignant brain tumor, is a highly aggressive and frequently recurrent neurologically destructive cancer that considered to be one of the most incurable human cancers. Remarkably, cancer stem cells are more resistant than other cancer cells to current cancer therapies, which often result in tumor relapse after initial tumor regression. Therefore, the drugs targeting cancer stem cells may have better therapeutic effect on cancers but lack of effective agents. Glioma stem cells (GSCs) are a small population of tumor cells existed in GBM, in which GSCs response to drive GBM recurrence, invasion and contribute to the anti-cancer resistance. It has been identified and developed as a therapeutic target for GBM and can be used in drugs screening. . In the previous study, we found two triterpenoids, euphol and 3-epilupeol, have showed selective inhibition towards GSCs and exhibited potent in vitro cytotoxicity. Further mechanism studies showed that they could decrease the GSCs cell proliferations, induce apoptosis through the cleaved-caspase-3 dependent cell apoptosis, and significantly arrest the cell cycle. Besides, it could damage the GSCs colony formation, decrease the number of the spheres significantly, and reduced the positive expression rate of GSCs marker CD44. These indicated that they are potential anti-GSCs reagents. . Based on the preliminary research, we will continue our investigation on the leading structures of these two active triterpenoids, euphol and 3-epilupeol. Guided by UPLC-QTOF-MS analysis and bioactive assay, more triterpenoids with similar structures are excavated efficiently from the locked active components. In addition, to further improve the anti-GSCs activity of isolated active natural compounds, including tirucallane-type and lupine-type triterpenoids, we will synthesize and evaluate their derivatives for their anti-GSCs activities. The anti-GSCs potential of the isolated and synthesized compounds will be comprehensively evaluated from the aspects of cell proliferation, cell migration, cell cycle and cell apoptosis, and mechanism of the system will be explored from the "molecular-cell-animal" level. The possible anti-GSCs mechanism of the active compounds will be explored to identify the potential target. This research may have important scientific significance for promoting the development and application of new drugs in the field of cancer stem cells.