Table_1_Decreased DUSP26 Expression Promotes Malignant Behavior in Glioblastoma Cells via Deregulation of MAPK and Akt Signaling Pathway.doc

PurposeDual-specificity protein phosphatases 26 (DUSP26) is a recently identified phosphatase enzyme that regulates MAPK and Akt signaling pathways. The role of DUSP26 in the development and prognosis of high-grade gliomas (HGGs) and primary glioblastoma (GBM) has remained unclear and was the focus of this study.
Materials and MethodsThe prognostic value of DUSP26 was assessed using retrospective analyses using online data sets and tissue microarray of HGGs. U251 and U87 cells modified to overexpress DUSP26 were utilized to study the role of DUSP26 in cell growth, migration, and cell apoptosis analyzed by CCK-8 assay, clonogenic, transwell migration, and TUNEL, respectively. The phosphorylation of proteins in MAPK and Akt signaling pathways was assayed by Western blot and immunofluorescence assays.
ResultsAnalyses using available online data sets and tissue microarray showed that DUSP26 is down-regulated in high-grade gliomas and GBM as compared to normal brain. Stratification of glioma patients based on DUSP26 expression level showed an inverse correlation between DUSP26 expression and patient survival. At the cellular level, DUSP26 overexpression led to decreased cell proliferation, migration, and senescence in U251 and U87 cells, whereas apoptosis was increased as compared to corresponding controls. Interestingly, the biologic effects of DUSP26 overexpression were associated with the dephosphorylation of proteins in the MAPK and Akt signaling pathways.
ConclusionsThese findings suggest that the loss of DUSP26 expression, seen in a subset of high-grade gliomas and GBM patients, facilitates malignant behavior; and with inverse correlation between its expression levels with patient survival. DUSP26 can serve as an independent prognostic factor.

研究目的：双特异性磷酸酶26（DUSP26）是新近发现的一种磷酸酶，可调控丝裂原活化蛋白激酶（MAPK）与蛋白激酶B（Akt）信号通路。目前双特异性磷酸酶26在高级别胶质瘤（HGGs）及原发性胶质母细胞瘤（GBM）的发生发展与预后中的作用尚不明确，本研究即以此为核心展开。
材料与方法：本研究通过回顾性分析在线数据集及高级别胶质瘤组织微阵列，评估DUSP26的预后价值。将经基因修饰过表达DUSP26的U251与U87细胞用于探究其在细胞增殖、迁移及细胞凋亡中的作用，分别采用CCK-8检测（CCK-8 assay）、克隆形成实验（clonogenic assay）、Transwell迁移实验（transwell migration assay）及TUNEL染色（TUNEL assay）进行分析。采用蛋白质印迹（Western blot）与免疫荧光染色（immunofluorescence assay）检测MAPK及Akt信号通路相关蛋白的磷酸化水平。
结果：现有在线数据集及组织微阵列分析显示，与正常脑组织相比，高级别胶质瘤及胶质母细胞瘤组织中DUSP26表达显著下调。根据DUSP26表达水平对胶质瘤患者进行分层分析后发现，其表达水平与患者生存期呈负相关。在细胞层面，过表达DUSP26可降低U251与U87细胞的增殖、迁移能力及细胞衰老水平，而相较于对照组，细胞凋亡水平有所升高。值得注意的是，DUSP26过表达的生物学效应与MAPK及Akt信号通路相关蛋白的去磷酸化作用密切相关。
结论：本研究结果表明，部分高级别胶质瘤及胶质母细胞瘤患者中存在DUSP26表达缺失的现象，该现象可促进肿瘤的恶性行为；且DUSP26表达水平与患者生存期呈负相关，其可作为一项独立的预后因子。