Suppression of growth of Bomirski Ab melanoma and its metastasis in hamsters by angiogenesis inhibitor TNP-470.

The growth of solid tumors and their metastasis is dependent on the development of new blood vessels (angiogenesis). In this study, we examined the effect of the angiogenesis inhibitor TNP-470 on a fast growing melanoma in hamsters. The effect was observed both on tumor growth and metastasis. Treatment with TNP-470 caused a significant decrease in the rate of tumor growth and suppression of the development of metastasis in 63% of treated animals. Some of the hamsters treated with TNP-470 had the tumor excised and the effect of that operation on the development of metastasis was examined. In such cases the inhibitory effect of TNP-470 was weaker than in tumor bearing animals. This indicates that excision of tumor created more favourable conditions for angiogenesis and that the dose of TNP-470 should be increased to be effective in such conditions.