Knockdown of eukaryotic translation initiation factor 4E suppresses cell growth and invasion, and induces apoptosis and cell cycle arrest in a human lung adenocarcinoma cell line

Eukaryotic translation initiation factor 4E (eIF4E) was shown to be upregulated in malignant human tumors. To assess the effect of downregulation of eIF4E on the proliferation and invasiveness of a human lung adenocarcinoma cell line, a short hairpin (sh)RNA targeting eIF4E was constructed and transfected into A549 human lung adenocarcinoma cells. The expression of eIF4E was determined by reverse transcription-quantitative polymerase chain reaction and western blotting. Cell viability was assessed using a Cell Counting kit-8, and apoptosis levels and cell cycle distribution were assessed by flow cytometry. Invasiveness was assessed using Transwell chambers. Transfection of the A549 cells with eIF4E targeting shRNA reduced the mRNA and protein expression levels of eIF4E by >70% 48 and 72 h following transfection, and eIF4E targeting shRNA-transfected cells were significantly less viable compared with the cells transfected with scrambled shRNA. The rate of apoptosis was also significantly increased, significantly more cells were in the G(0)/G(1) phase and fewer were in the S phase, indicating cell cycle arrest. The fraction of transfected cells migrating across Transwell inserts were also reduced. In conclusion, inhibition of eIF4E suppressed cell growth and invasion, induced apoptosis and cell cycle arrest, suggesting that eIF4E may be a potential therapeutic target in lung adenocarcinoma.