Secretion of metastasis related gangliosides by mouse B16-melanoma in circulation in vivo and in culture media in vitro.

Mouse B16LuF1 melanoma cells of lower metastatic potential to lung were treated in vitro with same concentration (50 microM) of gangliosides prepared from plasma of mice bearing lung metastasis of B16LuF5, B16LuF9 or B16LuF10 melanoma cell lines of increasing metastatic potential to lung (LuF1 < LuF5 < LuF9 < LuF10) and injected to normal mice through tail vein. The number of metastatic tumor nodules formed in lung increased gradually in mice receiving B16LuF5, B16LuF9 and B16LuF10-ganglioside-treated B16LuF1 cells compared to mice receiving B16LuF1 cells without any ganglioside treatment. Similarly, mouse B16LuF1 melanoma cells treated in vitro with 50 microM concentration of gangliosides prepared from spent culture media of B16LuF5, B16LuF9 or B16LuF10 cells cultured in vitro were injected to normal mice through tail vein. The number of metastatic tumor nodules formed in lung increased gradually in mice receiving B16LuF5, B16LuF9 and B16LuF10-ganglioside-treated B16LuF1 cells compared to mice receiving B16LuF1 cells without any ganglioside treatment. The results indicated that metastasis-associated gangliosides present in plasma and culture media of B16-melanoma of increasing metastatic potential to lung enhanced metastatic potential of B16LuF1 cells. The increasing concentration of metastasis-associated gangliosides present in plasma and in culture media of B16-melanoma of increasing metastatic potential possibly determined increase in metastatic potential of B16LuF1-melanoma cells.