Experimental model of liver metastases: adhesion and growth of cells on contact with endothelial or hepatocyte cell monolayer cultures.

In a rat colon carcinoma model (DHD/K 12-PROb), two varieties of cells were selected after in vivo passaging: PROb h2, representing a liver-specific variant and PROb Mp1, representing a lung metastatic variant and producing liver and lung metastases after intracecal injection (one out of four). The study of the adhesion and the growth of cells in vitro for contact hepatocytes and/or endothelial cells gave the following results: (1) except for PROb Mp1, tumor cell growth was independent of the cell support; (2) adhesion of PROb Mp1 to endothelial cells was lower between 30 and 120 min, whereas adhesion of PROb h2 to hepatocytes was greater and durable after 60 min (P < or = 0.05). These results suggest that the formation of liver metastases in a dynamic process and that tumor cells have a great ability to adhere to hepatocytes. Improved by serial passaging in vivo, our intracecal model might be useful for studying many aspects of the pathogenesis of colon cancer metastasis, while concurrent in vitro studies of the adhesion and growth ability of cells might be a useful indicator for assessing the in vivo behavior.