Abstract: Objective: To investigate the role of survivin antisense oligonucleotides(ASODN) in inducing the apoptosis of lung cancer cells and its mechanism.Methods: The lung cancer cell lines NCI-H446 were transferred with 100 nmol/L,300 nmol/L and 500 nmol/L survivin ASODN.The apoptosis index(AI)and the proliferation index(PI) were measured by flow cytometry(FCM).The cells were stained with Rh123 to detect the changes in the mitochondrial membrane potential(△Ψm) by FCM.While the concentration of cytoplasmic cytochrome c (Cyt C) was determined by ELISA,the relative activities of caspase-9 were detected by colorimetric assay.The apoptotic rates of lung cancer cells induced by survivin ASODN with or without caspase-9 inhibitor were measured by FCM.Results: When the NCI-H446 cells were treated with concentration of ASODN 500 nmol/L for 72 h,the AI was 48.35%,and the PI 24.38%.Survivin ASODN decreased △Ψm gradually,released Cyt C and activated caspase-9 significantly.The changes of the above indicators had time-dependent and time diversity relationship.In the presence of caspase-9 inhibitor,the apoptotic rates of lung cancer cells induced by survivin ASODN decreased significantly.Conclusions: Survivin inhibits apoptosis primarily via regulation of mitochondrial-dependent pathway.Survivin ASODN can not only induce apoptosis but also inhibit cell proliferation.