Human Lung Carcinoma A549-derived Conditioned Medium Activates Akt1 to Inhibit Apoptosis of Endothelial Cells

Objective To investigate the effect and mechanism of human lung carcinoma A549-derived conditioned medium (A549CM) on apoptosis of human umbilical veins endothelial cells (HUVECs).Methods HUVECs were treated with the A549CM,and cultured in 5% fetal bovine serum (FBS) as control.The apoptosis of HUVECs was assessed by Annexin-V-FITC labeling and fluorescence-activated cell sorting analysis.The small interfering RNA sequence specifically targeting protein kinase B Akt1 (named as siAkt1) and the scramble siRNA sequence siSCR (served as control) were constructed and chemically synthesized,and transfected into HUVECs with LipofectamineTM 2000.The expression of Akt1-mRNA was examined by RT-PCR,and the Akt protein expression level was checked by Western blotting analysis.The apoptosis of HUVECs was assessed.Results Compared with the control group,the A549CM significantly inhibited the apoptosis of HUVECs (3.03% vs 12.69%),siAkt1 significantly depressed the Akt1-mRNA (81%)and Akt protein (62%) expression level of HUVECs,and the apoptosis of siAkt1 and A549CM treated HUVECs increased significantly (P0.01).Conclusion Lung carcinoma A549-derived conditioned medium can depress the apoptosis of HUVECs by activating Akt1,which may provide a new molecular target for research on vasculogenesis of lung cancer and intervention therapy.