Plasminogen activators as markers of tumor colonization potential

Cell suspensions from the R 3230 AC rat mammary adenocarcinoma, when injected intravenously into F344 rats, invariably produce multiple lung foci within 10 days. We compared the colonization potential of cultures obtained from these foci and from cell populations exposed to 100 micrograms/ml medium of both concanavalin A and wheat germ agglutinin for 5 passages with the original cell line. Plasminogen activator activity (PAA) was determined in all three cell subpopulations, using S2251 (KABI) as chromogenic substrate. All cell lines retained their ability to grow after subcutaneous implant. The lectin resistant variant was found to have lost its capacity to nidate in the lung completely and also had the lowest PAA. In contrast, the cell population derived from the lung foci ranked highest in PAA.