ELEVATED STROMELYSIN-1 AND REDUCED COLLAGENASE-IV EXPRESSION IN INVASIVE RAT EMBRYO FIBROBLASTS EXPRESSING E1A DELETION MUTANTS + T24-H-RAS

We have studied the in vitro invasive properties of 3 cell lines derived from the co-transfection of rat embryo fibroblasts (REF) with EIA genes deficient in exon 2 and T24-ras. All 3 cell lines showed invasive properties at passage 10 after isolation. Invasive cells expressed elevated levels of stromelysin-1 and reduced levels of 68-kDa type-IV collagenase compared with untransfected REF. In 2 cell lines the invasive capacity increased during in vitro propagation. The expression of stromelysin-1 increased during this process, whereas 68-kDa type-IV collagenase was persistently expressed at reduced levels. In the third clone analyzed, the invasive capacity decreased during culture, in parallel with decreased expression of stromelysin-1. The low level of stromelysin-1 expression observed in this cell line did not result from loss of AP-1-transcription-factor activity, and was not reversed by phorbol-ester treatment.