Inhibition of hepatic metastasis in mice treated with cell-binding domain of human fibronectin and angiogenesis inhibitor TNP-470.
BACKGROUND: To prevent tumor metastasis, we administered the cell-binding domain of fibronectin, in combination with the angiogenesis inhibitor TNP-470, to mice with hepatic metastasis. We then assessed the prevention of tumor metastasis resulting from the inhibition of adhesive interactions and the inhibition of angiogenesis. METHODS: A hepatic metastasis model was created by injecting 1 x 10(3) colon 26/TC-1 cells into the anterior mesenteric vein of CDF1 mice. The cell-binding domain obtained from fibronectin included the Arg-Gly-Asp (RGD) sequence. A fibronectin-binding domain (FND)-treated group, an FND plus TNP-470 group, and a control group were established. The animals were killed 4 weeks after the injections of the treatment agents had been completed and the number of metastatic liver nodules was counted. In a simultaneous experiment with the same design, the mice were not killed at 4 weeks, and their survival was observed. RESULTS: The mean number of nodules in the FND plus TNP-470 group was significantly lower than that in the control group (P = 0.019337). The inhibition rate was 51% in the FND group, 60% in the FND 10 micrograms plus TNP-470 10 mg/kg group, and 64% in the FND 10 micrograms plus TNP-470 100 mg/kg group compared with the control group. Mice from the FND group that were not killed died after 6-8 weeks, but mice from the FND plus TNP-470 group died after 8-12 weeks. CONCLUSION: The cell-binding domain of fibronectin may, potentially, be an effective form of antiadhesive therapy that competes with native adhesion molecules and blocks adhesion during the metastatic process. When the cell-binding domain of fibronectin is combined with TNP-470 to inhibit angiogenesis, more effective inhibition of metastatic tumor growth and prolongation of survival can be achieved than after treatment with the cell-binding domain alone.