干预Skp2以增强胶质瘤细胞治疗敏感性的研究

放化疗抗拒是胶质瘤治疗的瓶颈。研究表明，胶质瘤干细胞的存在及DNA损伤的及时修复是胶质瘤治疗失败的重要原因。Skp2是泛素化修饰过程中的关键E3连接酶。我们已证实，Skp2调节造血干细胞及乳腺癌、鼻咽癌干细胞的数量和自我更新能力；Skp2能将MRN复合体的NBS1泛素化，进而募集和活化ATM，促进DNA损伤修复。然而，Skp2在胶质瘤干细胞以及DNA修复中的作用尚未见报导。因此我们推测靶向Skp2能够从多个角度同步增强胶质瘤细胞的放化疗敏感性。本研究将采用si/shRNA及Talen等基因敲除技术，及他汀类药物、小分子抑制剂等抑制Skp2，观察胶质瘤干细胞的数量和自我更新能力，放化疗引起的DNA双联断裂的修复等，从而评价靶向Skp2同步增敏放、化疗的潜力。本项目有望阐明胶质瘤对放化疗抵抗的新机制，为增敏放、化疗提供新的靶点，提供有效抑制剂，为改善胶质瘤患者的预后提供充分的科学依据。

Glioma is the leading brain tumor in adults and the patient prognosis was limited by treatment resistance greatly. It's been proved that the existence of glioma stem cells and the timely reparation of DNA damages are the main causes of treatment failure. Skp2 is the component of SCF complex, which serves as one of the important E3-ligase in the process of ubiquitination. Our group has demonstrated that Skp2 is involved in the regulation of pool size and self-renewal ability of hematopoietic stem cells, as well as breast cancer stem cells and nasopharyngeal carcinoma stem cell like cells. We also showed that Skp2 ubiquitinate NBS1, the components of MRN complex (Mre11/Rad50/NBS1), to recruit and activate ATM to initiate DNA damage reparation cascade. However, the exact role of Skp2 in the regulation of glioma stem cells and DNA damage reparation in glioma has not been elucidated yet. We propose here that targeting Skp2 could promote radio- and chemotherapy sensitivity through multiple pathways, including suppress function of glioma stem cells and attenuate the reparation of DNA double-strand breaks (DSBs) induced by alkylating reagents and ionizing radiation. We will adopt gene knockdown methods, statins, and small molecules to suppress the level of Skp2, and check pool size and self-renewal ability of glioma stem cell, and the reparation process of DNA DSBs upon radio/chemo treatments. In this way we can evaluate the role of Skp2 in repressing the glioma cell proliferation and subsequently triggering apoptosis. Our project will clarify the novel mechanisms about how Skp2 involved in the glioma radio- and chemotherapy resistance, which will provide a potential target to improve the radio/chemo therapeutic effect through targeting one single target. The fulfillment of our project will definitely provide scientific evidences in improving the prognosis of glioma patients in the near future.