The effects of EIF4E gene down-regulation induced by siRNA on the proliferation and cell cycle of human breast cancer cell line MDA-MB-231 / 肿瘤

ABSTRACT

Objective: To study the effect of down-regulation of eukaryotic translation initiation factor 4E (EIF 4E ) induced by the siRNA expression plasmid on the proliferation and cell cycle of human breast cancer cell line MDA-MB-231. Methods: The siRNA expression plasmid pGPU6/GFP/Neo-EIF4E was constructed and then transfected into breast cancer MDA-MB-231 cells by LipofectAMINE2000. The expressions of EIF4E and cyclin D1 mRNAs and proteins were examined by RT-PCR, Western blotting and the immunocytochemistry method, respectively. The MTT method, plate colony formation assay and flow cytometry were performed to detect the proliferation ability, cell colony formation rate and cell cycle distribution of MDA-MB-231 cells transfected with siRNA expression plasmid. Results: The siRNA expression plasmid pGPU6/GFP/Neo-EIF4E was constructed successfully. The expressions of EIF4E and cyclin D1 mRNAs and proteins were all decreased markedly after transfection with pGPU6/GFP/Neo-EIF4E (P <0.05). The growth of MDA-MB-231 cells in the pGPU6/GFP/Neo-EIF4E-tranfected group was inhibited and the cell colony formation rate was statistically decreased (P<0.05) as compared with those in the blank control and the pGPU6/GFP-transfected groups. The result of flow cytometry showed that the percentage of cells in G1 phase in the pGPU6/GFP/Neo-EIF4E-tranfected group was higher than that in the blank control group (71.30%±0.47% vs 53.10%±0.43%); however, the percentage of cells in S phase was signifcantly lower (12.53%±0.13% vs 26.47%±0.38%, P <0.05). Conclusion: EIF 4E siRNA can downregulate EIF 4E gene expression in human breast cancer MDA-MB-231 cells, suppress cell proliferation to some extent, and increase the number of cells in G1 phase with a decreased number of cells in S phase. EIF 4E gene may become one of the important molecular targets to breast cancer. Copyright© 2011 by the Editorial Board of Tumor.