CHARACTERIZATION OF A LIVER METASTATIC VARIANT OF MURINE COLON-26 CARCINOMA-CELLS

Intraportal vein injection of highly metastatic L5 cells consistently resulted in liver metastases (increases in the number of tumor colonie s in the liver), whereas inoculation of P cells rarely did. L5 cells i nvaded the basement membrane Matrigel in greater numbers than did P ce lls, suggesting that the metastatic potential of L5 cells is partly re lated to enhanced invasive properties. The enhanced adhesion of LS cel ls to fibronectin-, laminin- and Matrigel-coated substrates, as well a s their haptotactic migration to fribronectin, may be associated with the preferential expression of VLA-2 and VLA-4 integrins on the surfac e of these cells detected by flow cytometry. Gelatin zymograms showed that the degradative activity of 72-kD gelatinases was greater in L5 c ells than P cells. These results indicate that, in addition to adhesiv eness and motility, the invasive ability of L5 cells may also be attri buted to enhanced gelatinolytic activity. L5 cells grew more rapidly t han P cells in vitro. Thus, an experimental model using highly metasta tic colon 26 L5 cells would be useful for analyzing the molecular mech anism of liver metastasis and for evaluating the efficacy of treatment of occult micrometastases which may already have been disseminated at the time of surgery.