The role of both specific cellular adhesion and growth promotion in liver colonization by F9 embryonal carcinoma cells.

Unselected F9 murine embryonal carcinoma cells preferentially colonize the liver upon injection into tail veins of syngeneic mice, while the lungs are only very rarely colonized. Here we show that F9 cells attach better to fibronectin than to laminin in an adhesion assay, like other liver-colonizing cell lines. Moreover, assays of adhesion to extracellular matrix (ECM) prepared from rat organs (liver, lung and kidney) demonstrate that, in the absence of serum, F9 cells adhere better to liver- than to kidney- or lung-derived ECM. Even in the presence of FCS, the adhesion to lung ECM remains very low. This very low adhesiveness of F9 cells to lung-derived ECM correlates well with the finding that, in an organ distribution assay, tail-vein-injected F9 cells are very rapidly released from the lungs, when compared to the retention times of the lung-specific murine melanoma cell line B16-F10. Yet another property appears to contribute to organ-specific colonization of these cells: extracts of liver promote the growth of F9 cells, in contrast to extracts of lung or kidney which have no effect. These data suggest that preferential formation of metastases in the liver following the intravenous injection of F9 cells is the result of both their adhesive abilities and their growth response to local microenvironment.