Effect Of Avastin On Angiogenesis Of Human Gastric Cancer Growing Orthotopically In Nude Mice

Purpose: Vascular endothelial growth factor (VEGF) has been strongly implanted in the growth and metastasis of gastric cancer. The purpose of this study was to examine the effects of Bevacizumab, a monoclonal antibody developed against VEGF, with or without 5-Fu on the growth, metastasis and angiogenesis in a gastric cancer model which was orthotopically performed by two different operative methods with full intact tumor tissue blocks.Experimental Design: Metastasis model of human gastric cancer was established by orthotopic implantation of histologically intact human tumor tissue into gastric wall of nude mice. The operation was performed by two methods: traditional suturing method and organism biologic glue paste technique. All mice were divided into two teams and were operated by either methods. Then both teams were randomly divided into four groups 10 days after the transplantation: control group (saline solution), 5-Fu group (5-Fu 50mg/Kg i.p.), Bevacizumab group (Bevacizumab 1mg i.p.) and combined treatment of 5-Fu and Bevacizumab group. 52 days after implantation, the tumor weight, inhibition rates, intratumoral microvessel density (MVD), apoptotic index (AI) and the presence of metastasis were evaculated after the mice were sacrificed. The effects of the two operative methods on tumor weight, survival time, MVD, AI and metastasis was also determined.Results: Compared with control group, the growth of the orthotopically implanted tumor was significantly inhibited due to the reduced weight and the inhibition rate of tumor was 37.52%, 58.76% and 98.51% respectively in mice treated with 5-Fu, Bevacizumab and both. The number of metastastic foci in liver was significantly decreased only in the combined group compared with those in control group (0.99 ± 0.90 vs 6.50 ± 3.60). MVD was significantly decreased in Bevacizumab alone group and combination group (15.30+ 1.06 vs 8.40± 1.26 and 7.20± 1.23). The AI was increased significantly in the Bevacizumab alone group and combination group [(4.70± 1.70)% vs (11.50± 1.58)% and (13.60± 1.35)%]. The growth and angiogenesis...