Regulation of gelatinase production and invasiveness by organ-specific fibroblasts in high- and low-metastatic clones from murine RCT sarcoma.

Regulation of gelatinase production, invasiveness and migration activity by organ-specific fibroblasts from embryo, subcutaneous and lung tissues of mice were investigated in high-metastatic RCT+ and low-metastatic RCT- clones established from a poorly differentiated murine sarcoma. In the conditioned media of RCT+ cells, mouse skin fibroblasts (MSF) obtained from the tissue of tumor origin (orthotopic) stimulated the production of the 105-kD gelatinase more than C3H/ 10T1/2 clone 8 (C3H/10 T1/2 CL8) or mouse lung fibroblasts (MLF). In the conditioned media of RCT- cells, however, cocultivation with fibroblasts showed only slight stimulatory effects on the production of the 105-kD gelatinase. In the invasion assay, using a reconstituted basement membrane (matrigel), RCT+ cells cocultivated with MSF showed significantly higher invasiveness than those cocultivated with C3H/10T1/2 CL8 or MLF. However, no significant differences were shown in the invasiveness of RCT- cells in cocultivation with three types of fibroblasts and in cultivation without fibroblasts. There was no significant difference in migration activity between RCT+ and RCT- cells cultivated alone. But in the cocultivation of both clones with MSF, the migration activity of RCT+ cells was significantly higher than that of RCT- cells. These findings suggest that MSF might delineate the difference in characteristics related to the metastatic potential of RCT+ and RCT- cells through regulation by organ-specific factors.