Swainsonine Inhibition of Spontaneous Metastasis.

We have previously shown that swainsonine, administered systemically to C57BL/6 mice, inhibited the pulmonary metastasis of iv injected B16F10 melanoma cells by a mechanism involving interleukin-2 production and augmentation of natural killer cell activity. From this finding, which uses an “experimental metastasis” model system, we considered: whether swainsonine would be effective in the inhibition of authentic or spontaneous metastasis; whether the drug would also inhibit metastasis formation in organs other than the lungs; and whether the drug would block the metastasis of tumor cells of different histological type or origin. Our data indicated that swainsonlne effectively inhibited the spontaneous metastasis of B16-BL6 melanoma (by 88%) and M5076 reticulum sarcoma (by 95%) murine tumor cells to the lung and liver, respectively. In both cases, the antimetastatic activity of the drug increased as a function of the concentration in drinking water up to 3 µg/mL These findings indicate that the antimetastatic activity of swainsonine is not limited to artificial or experimentally induced metastasis nor to a single tumor type or specific organ. The inhibition of metastasis is likely due to a combination of events, which are currently under investigation. [ABSTRACT FROM PUBLISHER]