Eukaryotic initiation factor 3C silencing inhibits cell proliferation and promotes apoptosis in human glioma.

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.