INCREASES OF STROMELYSIN MESSENGER-RNA EXPRESSION IN RAS-TRANSFORMED REF CELLS IN-VIVO

Interstitial collagenase and stromelysin mRNA expression was examined in six rat cell lines isolated after transfection of embryo fibroblast s with polyomavirus large-T and T24-ras oncogenes. Increased levels of stromelysin mRNA were observed in tumors formed by cells with low lev els of stromelysin expression before injection, whereas interstitial c ollagenase mRNA levels were not elevated in tumors. The lung colonizin g - but not the chemoinvasive capacity - of two of these cell lines in creased following growth in vivo. The increase in stromelysin expressi on in tumors was not necessarily paralleled by an increase in ras expr ession. These findings may be relevant to the phenomenon of clonal dom inance of metastatic cells in primary tumors.