[Abstract] Objective To observe the effect of suramin combinated with PG-Rg3on xenograft growth of lung adeno- carcinoma in mice, and the related mechanism thereof. Methods Forty C57BL/6J mice bearing Lewis cells were random?ized into five groups: control group, cisplatin (DDP) group, suramin group, PG-Rg3group and combination group. Appropriate interventions were given in five groups of mice. Mice were sacrificed at day24after tumor inoculation. The subcutaneous tumors were stripped for histological examination. The tumor inhibitory rate was measured. The expressions of erythropoietinproducing hepatoma amplified sequences (Eph) B4protein, Bcl-2and tumors microvessel density (MVD) were determined by immunohistochemistry method with image analyze system. The apoptosis of tumor cells was measured by biotinyated dUTP nick and labeling (TUNEL) method. Results There were significantly lower values in subcutaneous tumor volume and weight in drug-treated groups than those in control group (P<0.05). The inhibitory rates were39.20%,49.11%,54.86% and62.49% in cisplatin group, suramin group, PG-Rg3group and combined group (P<0.05). The values of EphB4, MVD and Bcl-2grey values were significantly decreased, the apoptotic index was significantly increased, in suramin group, PGRg3group and combined group than those of control group and DDP group (P<0.05). The values of EphB4, MVD and Bcl-2 grey values were significantly increased, the apoptotic index was significantly decreased, in suramin group and PG- Rg3 group than those of combined group (P<0.05). Conclusion Suramin combinated with PG-Rg3can produce a synergetic inhibitory activity against tumor growth of lung adenocarcinoma, which may be associated with the effect of suppressing the expression of EphB4and angiogenesis, and the promotion of tumor cell apoptosis
