Survivin expression in human lung cancer and the influence of its downregulation on the biological behavior of human lung cancer cells.

The aim of the present study was to detect the expression of survivin in human lung cancer and to investigate the influence of its downregulation on the biological behavior of A549 lung cancer cells. The high expression of survivin in human lung cancer was verified by immunohistochemistry. Survivin small interfering RNA (siRNA) and unrelated sequence were synthesized and the siRNA lentiviral vector was constructed. The vector was transfected into A549 lung cancer cells, in which the clone with stable expression was screened out. We blocked the expression of survivin mRNA and protein by RNA interference (RNAi) technique. The downregulation of survivin mRNA and protein expression was confirmed by real-time quantitative PCR and western blotting. The proliferative activity and growth rate of A549 cells were determined by colony formation assay and mononuclear cell direct cytotoxicity assay (MTT assay). The reconstituted basement membrane (RBM) penetrating capacity was determined by cell invasion assay. The cell movement and migratory capacity were detected by wound-healing repair assay. The results showed that the sequence-specific siRNA significantly downregulated the expression of survivin at both the mRNA and protein levels. Downregulation of survivin expression dramatically decreased the invasive and metastatic capacities of the cells, suppressed the proliferation, decelerated the rate of growth, reduced the number of clones on soft agar and decreased the capacity of RBM penetration and migration. In conclusion, survivin, which plays an important role in carcinogenesis and development of lung cancer, can be effectively downregulated using the RNAi technique.