Preferential organ attachment and invasion in vitro by B16 melanoma cells selected for differing metastatic colonization and invasive properties.

Murine B16 melanoma sublines have been sequentially selected in vivo for low (B16-F1) or high (B16-F10) lung, high ovary (B16-O10) or high brain (B16-B15b) colonization, and in vitro for enhanced tissue invasion (B16-BL6). These B16 sublines were tested in vitro in a syngeneic organ adhesion/invasion assay to determine differences in tumor and/or host tissue properties that might account for preferential metastasis to certain sites. Tissues used were murine C57BL/6 lung, ovary and heart. In 8 independent experiments high lung-colonizing B16-F10 cells bound to and infiltrated into lung tissue better than ovary or heart tissue, while high ovary-colonizing B16-O10 cells attached to and invaded into ovary tissue at higher rates than lung or heart tissue. Only highly tissue-invasive B16-BL6 cells were able to invade heart tissue within 18 h in the experiments. The results suggest that organ metastatic colonization preferences by malignant cells may be determined, in part, by differences in the abilities of metastatic tumor cells to attach to and invade target tissue.