Suppression of vascular endothelial growth factor and angiopoietin­2 to treat adenocarcinoma of lung

Abstract

Objective To investigate whether RNA interference could induce gene silencing in lung adenocarcinoma cells as well as assess the degree of vascular endothelial growth factor(VEGF) and angiopoietin­2(Ang2) gene silencing and its effect on functional outcome. Methods Recombinant adenovirus AdVEGF shRNA and AdAng­2 shRNA were constructed driving by H1 promoter targeted on VEGF and Ang­2 utilizing gene recombinant technology.A549 cells was transfected with recombinant adenovirus.30 nude rats were randomly divided into 5 equal groups to be transplanted with AdVEGF shRNA­A549 cells，AdAng­2 shRNA­A549 cells，AdVEGF shRNA add AdAng­2 shRNA­A549 cells；Adnull­A549 cells and PBS only as blank control group.The growth of glioma was observed every five day.Thirty days Later， the rats were killed and the tumors were taken out to be examined.The tumor volume and weight were measured.The tumors were excised for immunohistochemistral staining of FⅧ­related antigen，VEGF，Ang­2，PCNA and TUNEL.Results We successfully constructed recombinant adenovirus mediating AdVEGF shRNA and AdAng­2 shRNA，the reproductive activity of the group transfected with AdVEGF shRNA and AdAng­2 shRNA A549 cell was inhibited obviously.Comparing non­transfecting group and tranfecting Ad­Null group，they had significant difference(P< 0.01).The tumor volume and weight had statistical significance between the group treated by AdVEGF shRNA/AdAng­2 shRNA or Ad­Null and PBS control group(P<0.01).Hemorrhage and lamellar necrosis were found in tumor treated by RNAi.Immunohistochemistral staining showed that the expression of Ang­2 and VEGF protein significantly decreased in the cancer cell treated by RNAi and meanwhile microvessel density decreased too.It also showed that apoptosis increased and cell reproductive activity was inhibited in the cancer cell treated by RNAi.Conclusions VEGF and Ang­2 may play an important role in lung adenocarcinoma progression.The specific small hairpin RNA targeting VEGF and Ang­2 can inhibit the expression of VEGF and Ang­2 protein and proliferation of lung adenocarcinoma cells in vitro and in vivo，the gene may become a target of gene therapy of lung adenocarcinoma.