Inhibition of eukaryotic initiation factor 3B suppresses proliferation and promotes apoptosis of chronic myeloid leukemia cells.

Background. Eukaryotic translation initiation factor 3B (eIF3b) has been reported to be overexpressed in colon, bladder and prostate cancers as well as in glioblastoma. However, there is no report on any correlation of eIF3b gene expression with cell proliferation and apoptosis in chronic myeloid leukemia (CML). Objectives. In this study, we evaluated the role of eIF3b in cell proliferation and apoptosis in CML. Material and methods. Samples from patients with CML and CML cell lines were used. Quantitative RT-PCR, siRNA transfection, flow cytometry, and western blot analysis were performed. Results. Quantitative RT-PCR revealed that the expression of eIF3b mRNA in CML patients was higher than that in the non-malignant controls. The proliferation of CML cells decreased after transfection of the cells with siRNA. The proportion of cells in the G1 and S phases in the experimental group decreased after transfection, while the number of cells in the G2/M phase increased, as compared with the control group. The total cell apoptosis percentage in the sheIF3b group (transduction with lentivirus-anti-eIF3b in K562 cells) was higher than the shCtrl group (transduction with empty-vector lentivirus in K562 cells) after transfection. Caspase 3/7 activity was higher and the expression of anti-apoptotic protein BCL-2 was lower in the sheIF3b group than in the shCtrl group after transfection. Conclusions. Our results suggest that downregulation of eIF3b expression inhibits proliferation and induces apoptosis in CML cells.