新型亚细胞核结构Paraspeckle的形成及其促进胃癌进展的机制和临床应用研究

Gastric cancer is one of the common human malignancies. Its 5-years survival rate is less than 25%.Paraspeckle is the new subnuclear structure whose function and mechanism are unclear. Our study firstly found that WTX loss correlated with gastric cancer progress, WTX targeted, the Paraspeckle skeleton molecule, LncRNA NEAT1, and miR-17 family induced WTX loss. Combining with the previous report that there are co-location of Paraspeckle and WTX, we suppose that miR-17 family silences WTX, then influences the formation of Paraspeckle through binding NEAT1 and regulating the progress of gastric cancer. To test this hypothesis, uncover the function, mechanism and clinical value of Paraspeckle in gastric cancer, this study will analyze the formation of Paraspeckle in gastric cancer, the function and mechanism of miR-17/WTX to NEAT1 expression and Paraspeckle formation by using qRT-PCR, immunofluorescence and Structured Illumination Microscopy (SIM); explore functional regulation by the cell function and protein expression and interaction experiment; and analysis the response and mechanism of Paraspeckle formation to chemotherapy. The gastric carcinoma in situ mice model will be established in WTX gene knockout mice or nude mice to validate the mechanism and clinical values in vivo. The new targets of Paraspeckle will be screened by ChIP analysis. Overall, this study will reveal the mechanism, function and clinical value of Paraspeckle formation during the tumorigenesis, provide a new direction for the mechanism studying and treatment of gastric cancer.

胃癌是人类常见恶性肿瘤之一,五年生存率不足25%；新型亚细胞核结构Paraspeckle在其中的作用和机制不清。我们前期研究首次发现WTX缺失与胃癌进展相关、WTX调控Paraspeckle关键骨架分子LncRNA NEAT1表达、miR-17家族介导WTX缺失；结合文献报道Paraspeckle分子与WTX存在共定位，推测miR-17家族沉默WTX，通过NEAT1影响Paraspeckle形成而调控胃癌进展。为验证这一假说并揭示其在胃癌发生发展中的功能机制及临床价值，本研究将分析胃癌中Paraspeckle形成情况、miR-17家族和WTX对NEAT1表达和Paraspeckle形成影响、功能和相互作用以及对化疗药物的反应；结合裸鼠及基因敲除小鼠胃原位癌模型整体验证以及新靶点筛选，研究将揭示胃癌进展过程中Paraspeckle形成机制、功能意义和临床价值，为胃癌机制和治疗研究提供新方向。

Paraspeckle在细胞核内的结构、动态改变、其各个组成分子之间作用关系、尤其是在肿瘤进展过程中的改变情况，尚不清楚，其在胃癌进展过程中的情况也未见报道。本研究发现，paraspeckle关键骨架分子lncRNA NEAT1在胃癌中高表达，与病人预后呈负相关；从细胞水平发现lncRNA NEAT1促进胃癌血管生成、细胞的增殖及迁移；机制上，lncRNA NEAT1通过直接靶向miR-17-5p调控TGFβR2的表达，从而促进胃癌血管生成；另外，WTX招募P54nrb在细胞核内点状聚集影响其与lncRNA NEAT1的结合负性调控paraspeckle形成，抑制胃癌进展。本项目揭示胃癌发生发展过程中，paraspeckle形成的功能意义、WTX基因失活的功能机制及其对NEAT1和paraspeckle调节作用与临床价值，为深入探讨胃癌发生发展机制提供新的认识，并为胃癌的分子靶向治疗提供新的依据和靶标。