知母皂苷AⅢ基于miR375-PDE5A-cGMP信号通路干预脑胶质瘤恶性增殖的机制研究

Malignant glioma is one of the most difficult cancers to cure and the prognosis is very poor. Preliminary data found that miR375 deficiency and high expression of PDE5A in malignant glioma cells and tumor tissues, consequently with the low accumulation of cGMP. The regulation of miR375-PDE5A-cGMP can inhibit glioma proliferation in vitro. Timosaponin AIII showed inhibition of malignant glioma proliferation and suppression of tumor growth in vivo and in vitro, and partly through the activation of cGMP signaling pathway. This project aims to compare normal cells, the glioma cells in different classification, clinical samples and database mining, analysis the relationship between miR375-PDE5A-cGMP and classification/prognosis, find the role of PDE5A in proliferation of glioma; figure out the therapeutic effect of cGMP on the progress of synthesis ,decomposition, pump out and signal regulation; identify the key subtype of PKG enzyme to explore the cross-talk between cGMP, β -catenin and MAPK signaling pathways, and explain the effect of timosaponin A III on glioma proliferation based on miR375-PDE5A-cGMP-PKG and other cross talk pathways. Research on timosaponin A III as PDE5 inhibitor from Traditional Chinese Medicine source on glioma proliferation may provide new strategies and candidate drugs for glioma treatment.

恶性脑胶质瘤是最难治愈的肿瘤之一，预后极差。前期研究发现恶性脑胶质瘤细胞和荷瘤组织中miR375缺失而PDE5A高表达，cGMP含量低，而体外干预miR375-PDE5A-cGMP可抑制增殖。知母皂苷AⅢ在体内外实验中有效抑制恶性脑胶质瘤增殖和生长，部分通过活化cGMP信号通路。本项目拟比较正常细胞、分级不同的胶质瘤细胞、临床样品并结合数据库挖掘，分析miR375-PDE5A-cGMP与分级预后的关系；从药理学、基因学、表观遗传学水平阐明PDE5A在增殖中的作用及调控机制；分析cGMP合成、分解、泵出和信号转递环节，揭示PKG关键亚型及其介导的cGMP与β-catenin及MAPK信号通路之间的交互作用。从分子、细胞、动物水平，考察知母皂苷AⅢ基于miR375-PDE5A-cGMP-PKG及其交互信号通路抑制脑胶质瘤增殖生长的作用机制。预期成果将为脑胶质瘤治疗提供新靶点和候选药物。

恶性脑胶质瘤是最难治愈的肿瘤之一，预后极差。本项目结果显示脑胶质瘤中miR-375缺失，导致靶基因PDE5的高表达，PDE5作为cGMP特异水解酶，导致cGMP的含量下调；调控miR-375-PDE5A-cGMP信号通路影响脑胶质瘤增殖生长；cGMP/PKG信号通路与β-catenin信号通路和MAPK信号通路存在相互作用，活化cGMP信号通路可抑制β-catenin和ERK信号通路的活化、活化p38和JNK信号通路，阐明了miR-375-PDE5A-cGMP信号通路参与脑胶质瘤的恶性增殖。在此基础上阐明了知母皂苷AⅢ通过提高miR-375水平，抑制PDE5A的表达，激活cGMP信号通路，调控β-catenin/MAPK信号通路而发挥抑制人脑胶质瘤细胞U87增殖和生长的作用；本项目结果为脑胶质瘤的治疗提供潜力靶点和药物候选物。