Comparative properties of untreated and N-nitrosobenzylmethyl-amine-transformed rat esophageal epithelial cell lines

A culture system utilizing rat esophageal epithelial cells has been developed. Four normal and eight N-nitrosobenzylmethylamine-treated lines were compared with respect to chromosome number, anchorage-independent growth in agarose, and tumorigenic potential in syngeneic rats. All cell lines were aneuploid with nine in the near-tetraploid range and three in the near-diploid range. No relation between tumorigenic potential and chromosome number or structure was apparent. Similarly, anchorage-independent growth in agarose did not correlate with tumorigenic potential. Three of the 12 immortalized lines (two carcinogen-treated and 1 untreated) induced well-differentiated squamous cell carcinomas in syngeneic rats. These tumors had weak metastatic potentials suggesting that tumorigenic potential and metastatic ability are separately controlled. These cell lines will be useful for the investigation of factors involved in the conversion of immortalized rat esophageal epithelial cell lines to lines of high metastatic potential.