SRGN在神经胶质母细胞瘤生长和转移中的作用及机制

Glioblastoma is the most common primary malignant brain tumor, with the highest degree of malignancy and the shortest survival time. It is a major problem to improve the prognosis of patients with glioblastoma. The applicants used the CRISPR-Cas9 library technology to screen for a new gene, SRGN, which is closely related to the growth of glioblastoma. Bioinformatics result suggested that SRGN is highly expressed in glioblastoma and is negatively correlated with the prognosis of patients. By constructing SRGN stable knockout glioblastoma cell line, high-throughput sequencing and gene sets function enrichment analysis found that SRGN is associated with the mTOR signaling pathway and the TGFb signaling pathway. In this project, We further investigate the role of SRGN in promoting the growth and metastasis of glioblastoma; elucidate the mechanism of SRGN in promoting the growth and metastasis of glioblastoma, analyze the regulation mechanism of SRGN on mTOR signaling, and the positive feedback regulation mechanism of SRGN and TGFb; explore the pathological significance of SRGN in the development of glioblastoma. The development of this project will provide a theoretical basis for clarifying the novel mechanism of glioblastoma development and finding novel targets for glioblastoma therapy.

胶质母细胞瘤是发病率最高，恶性程度最高，生存期最短的颅内原发恶性肿瘤，探索新的治疗方式成为改善胶质母细胞瘤患者预后亟待解决的重大课题。申请者前期采用CRISPR-Cas9文库技术，筛选获得与胶质母细胞瘤生长增殖密切相关的新基因SRGN。采用生物信息学发现SRGN在胶质母细胞瘤中高表达，且与患者的预后呈负相关；通过构建SRGN稳定敲除的胶质母细胞瘤细胞系，采用高通量测序、基因功能富集分析(GSEA)发现SRGN与mTOR信号通路及TGFb信号通路相关。据此，本项目拟在前期工作的基础上，进一步证实SRGN促进胶质母细胞瘤生长转移的作用；阐明SRGN促进胶质母细胞瘤生长转移的作用机制，解析SRGN对mTOR信号的调控作用、以及SRGN与TGFb的正反馈调控作用；探究SRGN在胶质母细胞瘤的发生发展中的病理意义。该项目的将为阐述胶质母细胞瘤发生发展新机制、寻找可行治疗靶标提供理论依据。

神经胶质母细胞瘤是发病率最高、恶性程度最高的颅内原发性恶性肿瘤。患者平均生存期仅14个月，5年生存率更是不到5%。神经胶质母细胞瘤具有增殖快、浸润性强的特征，阐明其迅速增殖机制，开发有效靶向药物，有望延长患者的生存期，改善预后。本课题通过采用CRISPR-Cas9技术筛选出丝甘蛋白聚糖(Serglycin,SRGN)在胶质母细胞瘤的增殖中发挥作用，细胞干预实验证实SRGN可以促进胶质母细胞瘤细胞的增殖及浸润能力，SRGN通过与CD44结合活化CREB1，激活TGFb的转录，TGFb2可激活Smad2/3的磷酸化，正反馈促进SRGN的表达。SRGN-TGFbeta2正反馈环路通过持续活化TGFb2信号通路，促进胶质母细胞瘤细胞的浸润。生长因子芯片结果提示SRGN促进PDGFA的分泌，通过实验证实SRGN通过结合PDGFA，促进其分泌，并进一步活化mTOR信号通路，促进胶质母细胞瘤细胞的增殖。SRGN在胶质母细胞瘤患者血清中，与PDGFA、TGFb2、IGF1等细胞因子的表达水平呈正相关，在胶质母细胞瘤患者组织中与肿瘤大小，临床分期呈正相关，提示其可能作为胶质母细胞瘤治疗的潜在靶标。