Abstract: Abstract:Objective To investigate the role of vascular endothelial cadherin (VE-cadherin) on the angiogenesis of non-small cell lung cancer(NSCLC),and to provide experimental basis for anti-angiogenic therapy of NSCLC.Methods The A549 cells were divided into blank control group,interference group and negative control group.VE-cadherin-siRNA was transiently transfected into A549 cells,and Real-time quantitative PCR and Western blotting methods were used to detect the expression levels of VE-cadherin mRNA ;the changs of cell absorbance(A490) value was detected by four methy1 thiazolyl tetrazolium(MTS) assay;the cell cycle and apoptosis were detected by flow cytometry;the expression level  of VE-cadherin in transiently transfected A549 cells supernatant was detected by ELISA method;the  changes of   the A490 value,ratios of cell cycle(G0/G1,G2/M and S),apoptotic rate and Matrigel tubule formation number of human  umbilical vein endothelial cells(HUVECs) were analyzed after treated with supernatant.Results The expression level of VE-cadherin mRNA in interference group (0.299±0.039) was significantly lower than those in blank control group(1.137±0.082) and negative control group (1.001±0.076) (P<0.05);the expression level of VE-cadherin  protein in interference group(0.297±0.045)〖JP2〗 was significantly lower than those in blank  control group (0.833±0.119) and negative control group (0.794±〖JP〗0.095)(P<0.05).The A490 values,cell cycle ratios and  apoptotic rates of the  A549 cells in blank control group,interference group and negative control group had no significant differences(P>0.05);the expression level of VE-cadherin in the supernatant in interference group was （2.89±0.07）μg/L,which was significantly lower  than those in blank control group ［(11.43±0.09) μg/L］ and
 negative control group ［(11.15±0.04) μg/L］ (P<0.05).Between  interference group  and  negative group,the percentages of  HUVECs  at G0/G1,G2/M and S phases had no significant difference after treated with supernatant(P>0.05);but the proliferation of HUVECs  in interference group was inhibited by supernatant  significantly,the inhibitory rates of cell proliferation  24,48 and 72 h after treatment were 29.2%,33.8%,and 30.1%,respectively.48 h after treatment,the apoptotic rate of the HUVECs in  interference group  was 27.12%±5.22%,which was significantly higher than that in negative control group (13.43%±3.50%) (P<0.05).The number of tubule formation was 1.53±0.31,which was significantly lower than that in  negative control group（14.53±1.51）(P<0.05). Conclusion VE-cadherin may participate in the occurrence and development of NSCLC by promoting angiogenesis,which is expected to become a new target for  anti-angiogenic therapy of NSCLC.

Key words: vascular endothelial cadherin, angiogenesis, cancer,non-small cell lung, human umbilical vein endothelial cells