Shi Guohong, Zhang Zhen
Department of Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.
Oncol Lett. 2021 Apr;21(4):314. doi: 10.3892/ol.2021.12575. Epub 2021 Feb 23.
Glioma is one of the most common primary brain tumors and has a poor prognosis. Rap2B, a member of the Ras family of oncogenes, is highly expressed and promotes the progression of several tumors, including glioma. However, the mechanism underlying the role of Rap2B in glioma is not fully understood. In the present study, after transfection, Rap2B expression was detected by reverse transcription PCR and western blot analysis. Cell proliferation and cell migration assays were performed to determine the effects of Rap2B on the malignant biological behaviors of glioma cells. The changes of ERK pathway-associated proteins were examined by western blot analysis. Enzyme-linked immunosorbent assay (ELISA) and western blot analysis were utilized to detect the protein levels of matrix metalloproteinase (MMP)2 and MMP9. Then, The Cancer Genome Atlas database was used to determine the association between Rap2B expression and clinical parameters in patients with glioblastoma multiforme and low-grade glioma (LGG). Results revealed that Rap2B was highly expressed in human glioma compared with that in adjacent normal tissues and normal human astrocytes, and that silenced Rap2B led to a reduction of cell proliferation and migration ability in glioma cells. Conversely, overexpressed Rap2B in both U87 and U251 cells significantly enhanced these malignant activities. In addition, ELISA assay and western blotting showed that Rap2B increased MMP2 and MMP9 expression. The western blot assay revealed that Rap2B induced the phosphorylation of ERK in glioma cells. Furthermore, silencing the ERK pathway by SCH772984 led to the inhibition of Rap2B-mediated proliferation, migration and the reduction of MMP2 and MMP9 expression. Kaplan-Meier analysis revealed that increased Rap2B expression was associated with poorer survival of patients with LGG. These results demonstrated that Rap2B may participate in the processes of glioma cell proliferation and migration through enhancing MMP2 and MMP9 expression via the ERK pathway. Thus, Rap2B could potentially be used as a promising therapeutic target and prognostic biomarker in glioma.
胶质瘤是最常见的原发性脑肿瘤之一，预后较差。Rap2B是Ras癌基因家族的成员之一，在多种肿瘤（包括胶质瘤）中高表达并促进肿瘤进展。然而，Rap2B在胶质瘤中发挥作用的潜在机制尚未完全明确。在本研究中，转染后通过逆转录PCR和蛋白质印迹分析检测Rap2B的表达。进行细胞增殖和细胞迁移实验以确定Rap2B对胶质瘤细胞恶性生物学行为的影响。通过蛋白质印迹分析检测ERK通路相关蛋白的变化。利用酶联免疫吸附测定（ELISA）和蛋白质印迹分析检测基质金属蛋白酶（MMP）2和MMP9的蛋白水平。然后，使用癌症基因组图谱数据库确定Rap2B表达与多形性胶质母细胞瘤和低级别胶质瘤（LGG）患者临床参数之间的关联。结果显示，与相邻正常组织和正常人星形胶质细胞相比，Rap2B在人胶质瘤中高表达，沉默Rap2B可导致胶质瘤细胞的增殖和迁移能力降低。相反，在U87和U251细胞中过表达Rap2B可显著增强这些恶性活性。此外，ELISA检测和蛋白质印迹显示Rap2B增加MMP2和MMP9的表达。蛋白质印迹分析显示Rap2B诱导胶质瘤细胞中ERK的磷酸化。此外，用SCH772984抑制ERK通路可导致Rap2B介导的增殖、迁移受到抑制，MMP2和MMP9表达降低。Kaplan-Meier分析显示，Rap2B表达增加与LGG患者较差的生存率相关。这些结果表明，Rap2B可能通过ERK通路增强MMP2和MMP9的表达参与胶质瘤细胞的增殖和迁移过程。因此，Rap2B有可能作为胶质瘤中一个有前景的治疗靶点和预后生物标志物。
