PIN1调控自噬终止参与胶质母细胞瘤发生发展

Autophagy is a conserved self-renewal mechanism in eukaryotes and plays an important role in the development of tumors. The formation and termination of autophagosome is a dynamic process determined by the environment. It is toxic to cells if autophagy is not initiated or terminated properly. Although many studies have focused on the initiation of autophagy, the mechanisms of autophagy termination are still unclear. Applicants' previous studies have shown that autophagy in PIN1-knockout cells is not terminated properly, but underlying mechanisms are unclear. To this end, in this study, we will use glioblastoma cell as a model to further verify the biological roles of PIN1-mediated autophagy termination. We will study the molecular mechanism of PIN1-mediated autophagy termination through examining the formation and dissociation of autophagy-related complex and analyze the regulation of PIN1 in different stage of autophagy. Finally, we will explore the role of PIN1 in the regulation of glioblastoma cell proliferation and investigate its clinical significance in the development of tumor. This project will provide a better understanding on the mechanism of autophagy and its role in tumor chemotherapy, and will be helpful for optimizing the existing glioblastoma treatment strategy.

自噬是真核生物中保守的自我更新机制，在肿瘤发生发展中扮演重要角色。自噬体的形成与消灭是一个由环境决定的动态过程，自噬不能及时激活与不能适时终止均不利于细胞生存。尽管已有较多研究关注自噬的发生，但自噬终止的调控机制仍不清楚。申请者前期研究显示，在肽基脯氨酰顺反异构酶PIN1缺失的细胞中，自噬无法正常终止，但作用机制尚不明确。为此，本项目拟以我国高发的胶质母细胞瘤为模型，进一步验证PIN1调控自噬终止的生物学功能。以自噬相关复合物的形成和解离为切入点，研究PIN1调控自噬终止的分子机制，分析PIN1自身在自噬不同阶段的调控机制，探讨其在调控胶质母细胞瘤细胞增殖中的作用，并阐释其在肿瘤发生发展中的临床意义。本项目的实施，有助于揭示自噬的调控机制，更深入地了解肿瘤发生发展的一般性规律，更清晰地认识自噬在肿瘤化疗中的角色，优化现有的胶质母细胞瘤治疗策略。

本项目利用蛋白质组学结合生物信息学筛选鉴定了肽基脯氨酰顺反异构酶PIN1的作用底物ULK1，发现缺氧诱导的ULK1 R170me2s激活了自噬，进一步研究表明ULK1 R170me2s在线粒体周转中起着关键作用，并在应对缺氧压力时维持细胞的活力，促进肿瘤细胞增殖。通过对胶质瘤患者临床组织样本分析，我们明确了ULK1 R170 me2s在肿瘤发展中的临床意义。同时发现PIN1可作为胶质瘤患者不良预后与肿瘤恶性程度的标志物。以上研究结果为以PIN1为靶点的抗肿瘤策略研发提供了依据。另一方面，项目组选择了胡桃醌，一种天然植物来源的PIN1抑制剂，制备了基于H2O2自调节的载胡桃醌仿生纳米粒子，证实了载药体系的抗肿瘤效应，为肿瘤治疗提供了新的思路和途径。