Hao Jinmin, Wang Zhiming, Wang Yaowu, Liang Zhaohui, Zhang Xin, Zhao Zongmao, Jiao Baohua
Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shi Jiazhuang, Hebei 050000, P.R. China.
Department of Neurosurgery, Tangshan Gongren Hospital of Hebei Medical University, Tangshan, Hebei 050000, P.R. China.
Oncol Rep. 2015 Jun;33(6):2954-62. doi: 10.3892/or.2015.3881. Epub 2015 Mar 30.
Eukaryotic initiation factor 3, subunit c (eIF3c), an oncogene overexpressed in human cancers, plays an important role in cell tumorigenesis and proliferation. However, studies assessing its function in gliomas are scarce. The present study evaluated for the first time, the role of eIF3c in gliomas. Immunohistochemistry was carried out to assess eIF3c expression in 95 human glioma samples and normal brain tissues. Then, the eIF3c mRNA levels were detected in tumor and normal brain specimens by quantitative RT-PCR. In addition, eIF3c mRNA levels were assessed in four glioma cell lines (U87, U251, A172 and U373) by semi-quantitative RT-PCR. The RNA interference (RNAi) technology was employed to knock down the eIF3c gene in the U251 cells. Western blot analysis, BrdU assay and flow cytometry were used to measure eIF3c protein levels, cell proliferation, cell apoptosis and cell cycle, respectively. The eIF3c protein was overexpressed in the human glioma specimens. In agreement, the eIF3c mRNA expression levels were significantly higher in the human glioma tissues compared with the normal brain samples (P<0.0001). In addition, eIF3c mRNA was detected in all the glioma cell lines. Silencing the eIF3c gene in the U251 cells by RNAi significantly suppressed cell proliferation (P<0.01) and increased apoptosis (P<0.01). Finally, a stark decrease was observed in the G1 phase cell number (P<0.01), while the S and G2 phase cells were significantly increased (P<0.01) after eIF3c knockdown. These findings suggest that eIF3c is overexpressed in human gliomas and essential for their proliferation and survival. Therefore, inhibiting eIF3c expression may constitute an effective therapy for human glioma.
真核生物起始因子3亚基c（eIF3c）是一种在人类癌症中过表达的癌基因，在细胞肿瘤发生和增殖中起重要作用。然而，评估其在胶质瘤中功能的研究很少。本研究首次评估了eIF3c在胶质瘤中的作用。采用免疫组织化学方法评估95例人类胶质瘤样本和正常脑组织中eIF3c的表达。然后，通过定量逆转录-聚合酶链反应（RT-PCR）检测肿瘤和正常脑标本中eIF3c的mRNA水平。此外，通过半定量RT-PCR评估四种胶质瘤细胞系（U87、U251、A172和U373）中eIF3c的mRNA水平。采用RNA干扰（RNAi）技术敲低U251细胞中的eIF3c基因。分别用蛋白质免疫印迹分析、BrdU检测和流式细胞术检测eIF3c蛋白水平、细胞增殖、细胞凋亡和细胞周期。eIF3c蛋白在人类胶质瘤标本中过表达。同样，与正常脑样本相比，人类胶质瘤组织中eIF3c的mRNA表达水平显著更高（P<0.0001）。此外，在所有胶质瘤细胞系中均检测到eIF3c的mRNA。通过RNAi沉默U251细胞中的eIF3c基因可显著抑制细胞增殖（P<0.01）并增加细胞凋亡（P<0.01）。最后，在敲低eIF3c后，观察到G1期细胞数量明显减少（P<0.01），而S期和G2期细胞显著增加（P<0.01）。这些发现表明，eIF3c在人类胶质瘤中过表达，对其增殖和存活至关重要。因此，抑制eIF3c的表达可能成为治疗人类胶质瘤的有效方法。
