Knockdown of autophagy-related gene BECLIN1 promotes cell growth and inhibits apoptosis in the A549 human lung cancer cell line.

The expression of BECLIN1 is significantly reduced in non­small cell lung cancer (NSCLC) compared with non­cancerous tissue. However, the role of BECLIN1 in lung cancer is unclear. Using the RNA interference (RNAi) technique the present study investigated the effect of the knockdown of BECLIN1 on the cell growth and proliferation of the A549 human lung cancer cell line. The target site for the RNAi technique was designed and the lentivirus vector for the small interfering (si)RNA expression was constructed according to the encoding sequence of the mRNA for BECLIN1. The A549 cells were transfected with the siRNA virus against BECLIN1. BECLIN1 expression was detected by reverse transcription (RT)­PCR and western blot analysis. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was applied to detect cell growth. Flow cytometry was used to determine cell apoptosis. The activity of caspase­3 and caspase­9 was also detected in the A549 cells with BECLIN1 knockdown. The results showed that siRNA virus transfection significantly decreased the mRNA and protein expression of BECLIN1 in the transfected A549 cells. The knockdown of BECLIN1 promoted cell growth and decreased apoptosis. Caspase­3 and ­9 activity in the A549 cells with BECLIN1 knockdown was significantly reduced. In conclusion, the siRNA expression vector effectively inhibited the expression of BECLIN1 in the A549 human lung cancer cell line and promote the growth and proliferation of the A549 cells.