Specific Organ Metastases of Human Melanoma Cells Injected into the Arterial Circulation of Nude Mice

The purpose of this study was to examine whether organ specific metastasis can be produced by different subpopulations of cells isolated from a single human melanoma. Three clones, SB1, SB2, SB3, and a variant line SB1 Asc (obtained from ascites fluid after i.v. inoculation of SB1 cells in a nude mouse) - all isolated from a primary human cutaneous melanoma - were inoculated into the left ventricle (i.c.) or intravenously (i.v.) into nude mice. Three to 16 weeks later, the animals were killed and autopsied. The clones produced different patterns of metastasis. Three to 4 weeks after i.c. inoculation of 2 x 10(6) cells, cells of clone SB1 produced numerous rapidly progressing metastases in the brain, whereas cells of SB1 Asc produced large metastases in the adrenals and sometimes in the ovaries. Cells of clones SB2 and SB3 produced a few small metastases without any characteristics pattern. The initial arrest of tumor cells in various organs did not predict the outcome of metastasis. This conclusion is based on studies of distribution and fate of tumor cells labeled with 111Indium Oxine. Therefore, organ specific metastasis produced by human melanoma cells inoculated i.c. into nude mice is likely to depend on the interaction of unique metastatic cells with organ environment.