OBJECTIVETo evaluate the effects of Bevacizumab on the tumor growth, proliferation and apoptosis of gastric cancer xenograft, and the impacts on the VEGF and Sp1 expression.

METHODSGastric cancer xenografts in nude mice were established using SGC-7901 gastric cancer cell line. The nude mice were randomly divided into two groups, Bevacizumab treatment group and PBS group. The tumor sizes were measured for tumor growth curve. The proliferation and angiogenesis were evaluated by immunohistochemistry (IHC) staining of Ki67 and CD34. TUNEL assay was used for apoptosis evaluation. The expression of VEGF and Sp1 in tumor cells were detected by IHC and Western blot.

RESULTSCompared to the PBS group, the tumor growth decreased significantly (P<0.05), the proliferation of tumor cells and angiogenesis decreased, and apoptosis index increased significantly [(5.3 ± 1.8)% vs. (16.7 ± 6.7)%, P<0.01] in Bevacizumab group. The results of IHC and Western blot demonstrated that the expression of VEGF and the microvessel density (MVD) was decreased (4.0 ± 1.0 vs. 16.3 ± 1.5, P<0.001) in Bevacizumab treatment group. No obvious changes of Sp1 expression were observed in Bevacizumab treatment group.

CONCLUSIONSBevacizumab can inhibit the growth of gastric cancer xenografts in nude mice, decrease the VEGF expression and MVD. However, the compensatory up-regulation of transcription factor Sp1 is not affected by Bevacizumab.