Effect of siRNA on Expression of Eukaryotic Initiation Factor 4E in Human Esophageal Carcinoma EC9706 Cells

Objective To investigate the effects of small interfering RNA(siRNA) on the expression of eukaryotic initiation factor 4E(eIF4E) gene in human esophageal carcinoma EC9706 cells. Methods By the sequence of eIF4E gene in GeneBank， the oligonucleotide templates encoding two specific siRNAs and a nonsense siRNA of eIF4E gene were designed and synthesized，and then all the siRNAs were synthesized by in vitro transcription. EC9706 cells were transfected by each siRNA at the concentration of 150ng/μl，200ng/μl and 250ng/μl for 24h，48h and 72h respectively. The normal group was set as control at the same time. The expression of eIF4E protein and mRNA before and after transfection were detected by using immunocytochemistry and in situ hybridization. Changes of cell cycle in EC9706 cells before and after transfection were detected by application of flow cytometry. Results It was observed that EC9706 cells had morphological changes after the transfection. Compared with normal group，there was a significant decrease of the eIF4E protein and mRNA level in every specific siRNA transfection group of different concentration meanwhile a significant dose-dependent manner（P<0.05），was also observed. However there was no significant difference between the two transfection groups(P>0.05). Nonsense siRNA did not show inhibitory effect on the expression of eIF4E gene(P>0.05). The two specific siRNA can obviously depress the expression of eIF4E compared with the nonsense siRNA. The difference has statistical significance（P<0.05）.After the transfection of specific siRNA for 72h, the proportion of G₀/G_1 phase cells increased significantly, while the proportion of S-phase cells reduced. The difference has statistical significance(P＜0.05). Conclusion Specific siRNA can effectively inhibit the expression of eIF4E gene in human esophageal carcinoma EC9706 cells.