Activated K‐ras in Tumorigenic and Non‐tumorigenic Cell Variants from a Rat Colon Adenocarcinoma, Induced by Dimethylhydrazine

Using NIH3T3 cell transfection assay, activated c‐K‐ras was detected in two cell lines, TRb and TSb, obtained from a single colon adenocarcinoma induced in a rat by 1,2‐dimethylhydrazine. TRb cells give rise to progressive and metastatic tumors in the syngeneic rats, whereas TSb cells only induce regressive tumors. Levels of K‐ras transcripts in TRb and TSb cells were higher than that of NIH3T3 cells, but no difference was found between TRb and TSb cells. No significant difference was observed in expression levels of c‐myc in these two cell lines, c‐fos expression was, however, significantly lower in TRb than TSb cells.