解析ALDH1A3基因启动子区甲基化调控脑胶质瘤恶性进展的分子机制

Glioma is the most common form of brain tumor, and invasion and recurrence is the main reason for its poor prognosis. In our previous studies, whole-genome DNA methylation profiling was performed and revealed that the methylation status of ALDH1A3 promoter was associated with clinical prognosis in glioblastoma (GBM) patients. To date, the molecular mechanisms of ALDH1A3 promoter methylation and protein expression in gliomagenesis have not yet been elucidated. Here, we propose a hypothesis that ALDH1A3 gene expression level, which is regulated by its promoter methylation status, may contribute to the malignant phenotype of gliomas and be a potential biomarker of molecular targeted therapy. To verify the above hypothesis, we will analyze the clinical significance of ALDH1A3 in a large number of clinical specimens and explore its functional role in gliomas via a series of molecular biology avenues in vitro and in vivo, such as pyrosequencing, RNAi, cell function assays, yeast two-hybrid system, co-immunoprecipitation, xenograft, et al. In summary, the present study aims to investigate the role of ALDH1A3 promoter methylation and protein expression in gliomagenesis and evaluate the possibility of ALDH1A3 as a potential target for gene therapy.

胶质瘤是最常见的颅内肿瘤，侵袭及复发是其预后不良的主要原因。我们前期研究利用全基因组甲基化芯片分析胶质母细胞瘤临床样本，筛选并鉴定出ALDH1A3启动子区甲基化状态与患者临床预后密切相关，但其在脑胶质瘤中的作用机制目前还未见报道。为此，我们提出假说：ALDH1A3启动子区甲基化状态调控基因表达，从而影响胶质瘤细胞恶性进展。为了验证这一假说，我们将通过大规模临床样本、体外细胞系和动物成瘤模型，采用焦磷酸测序、小干扰RNA慢病毒转染、细胞生物学功能检测、酵母双杂交、免疫共沉淀等技术手段，从分子、细胞、组织以及动物整体水平探讨ALDH1A3基因在胶质瘤发生发展中的重要作用，阐明ALDH1A3启动子区甲基化导致基因表达沉默，进而调控胶质瘤恶性进展的分子机制。本研究将从ALDH1A3启动子区甲基化这个新视点为揭示脑胶质瘤的发病机理奠定基础，为脑胶质瘤的分子诊断、预后判断及分子靶向治疗提供新的思路。

胶质瘤是最常见的颅内肿瘤，侵袭及肿瘤干细胞是其复发及预后不良的主要原因。我们利用全基因组甲基化芯片分析胶质母细胞瘤临床样本，筛选并鉴定出 ALDH1A3 启动子区甲基化状态与患者临床预后密切相关，进而调控胶质瘤恶性进展。在细胞水平，我们证实ALDH1A3可以作为间质型胶质瘤特异性标志物，并参与胶质瘤细胞的侵袭。同时，我们在研究中发现ALDH1A3与胶质瘤干细胞间关系密切，能够调控胶质瘤干细胞的恶性生物学行为，可能在胶质瘤干细胞由PN 表型向 MES 表型转化中发挥重要作用，从而导致肿瘤恶性进展以及患者生存预后恶化。本研究为揭示脑胶质瘤的发病机理奠定基础，为脑胶质瘤的分子诊断、预后判断及分子靶向治疗提供新的思路。