Abstract:Objective:To study the expression of Ang-2 in gastric carcinoma tissue, and its relation with pathological stage, To investigate the biological effects of antisense Ang-2 cDNA （pEGFP-N1-anti-Ang-2 cDNA）in human SGC-7901 gastric carcinoma cell line. Methods: Immunohistochemical method was used to detect the expression of Ang-2 protein in 53 samples of gastric carcinoma tissues, and western blot technique was used to the expression of Ang-2 protein in 10 samples of gastric carcinoma tissues and 10 normal gastric tissues. Using the lipofectamine 2000 transfection technique,We transferred separately two different plasmids induding pEGFP-N1,pEGFP-N1- antisense Ang-2 cDNA into an in vitro cultured human gastric carcinoma cell line SGC-7901. The expression of Ang-2 mRNA in 53 gastric carcinoma tissue specimens were determined by RT-PCR. Immunohistochemistry was used to detect the expression of Ang-2 in those tissues as well.The cell viability was detrmined by MTT assay.Apoptosis was determined by flow cytometry . the three kinds of gastric carcinoma cells were subcutaneously injected into 30 nude mice divided into three groups freely. After injection, the tumor mass grew and the angiogenesis of the tumor could be detected. Results:Ang-2 was expressed in gastric carcinoma tissue, while normal gastric tissue was unexpressed. An increased expression of Ang-2 was strong association between the different pathological stages of tumors. On RT-PCR and immunohistochemical method,the SGC-7901 cells transfected antisense Ang-2 gene did not show expression of Ang-2 mRNA and its protein.MTT assay showed the group transfected with antisense Ang-2 gene had a much lower cell viability than other groups(P＜0.05).The group also had an increase in the rate of apoptosis as measured by flow cytometry Compared with other groups(P＜0.01). the tumor grew slower in transfected mice with antisense Ang-2 gene than other groups. The average number of newly formed vessels in the transfected mice with antisense Ang-2 gene was smaller than other groups（P＜0.05）. Conclusions:Ang-2 plays an important role in the angiogenesis and tumor growth, the expression of Ang-2 mRNA and its protein in SGC-7901 cells can be inhibited by antisense Ang-2 gene.The study also show that antisense Ang-2 gene can suppress the in vitro growth of human gastric carcinoma cells. The antisense Ang-2 gene may suppress growth and angiogenesis in the human SGC-7901 gastric carcinoma apparently.
