[Transformation of rat esophageal precancerous epithelial cells and its biologic characteristics--establishment of RE25-3 esophageal carcinoma cell line].

A neoplastic transformation cell line (RE25-3) of the rat esophageal precancerous epithelium has been established by in vivo-in vitro method in our laboratory. Ten criteria were used to study the biological characteristics of the neoplastic transformation during various stages: 1. Dysplastic lesion of the esophageal epithelium was induced in wistar rat by oral administration of NSEE. The dysplastic epithelium was then removed and cultured. After several generations of subculture without carcinogen, the dysplastic epithelium showed neoplastic transformation in vitro. 2. The maximum mitotic index of the transformed cell reached 2.0% and two peaks were observed at hour 41 and 96, respectively, while the mitotic index of the normal esophageal cell was 0.6%. 3. DNA measurement was performed by MSP. The results showed disappearance of the diploid cell from the fifth subculture. Tetraploid, heteroploid and aneuploid cells were observed from the third subculture. The aneuploid cells amounted to 86.24%. 4. The number of chromosome increased as the time of culture as well as the number of subculture generation increased. Chromosome aberration was observed. 5. As the number of subculture generation increased, the damage and break of the chromosome increased. Micronuclei rate increased. 6. By incorporation of H3-TdR, DNA synthesis rate increased as the malignancy increased. 7. Growth of the RE25-3 cell was dependent on EGF in the early stage. But after 15 subculture, as neoplastic transformation developed, this dependency disappeared. 8. After 14 generations of subculture, the cell can be cultured in soft ager. 9. Keratin was proved positive within the cell by ABC immuno-histochemistry assay.(ABSTRACT TRUNCATED AT 250 WORDS)