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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 E1A 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‐I 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‐I 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‐I. The low level of stromelysin‐I expression observed in this cell line did not result from loss of AP‐I ‐transcription‐factor activity, and was not reversed by phorbol‐ester treatment. © 1992 Wifey‐Liss, Inc.