细胞培养中的癌变原理研究Ⅲ.丁酸诱导金仓鼠恶性转化细胞的表型逆转和染色体非随机改变

Studies on Mechanism of Carcinogenesis in Cell Culture Ⅲ. Butyric Acid-induced Phenotypic Reversion ofMalignant Transformed Syrian Hamster Lung Cells (BHLB_4)

用2mmol/L丁酸长期处理金仓鼠恶性转化细胞,得到一个丁酸依赖型的逆转细胞系.逆转细胞在形态、核质比例、增殖速度、琼脂表面生长能力等生物学指标上均接近正常细胞;且细胞内cAMP水平也有较大幅度提高。遗传学分析结果表明,与金仓鼠细胞癌变相关的第15号染色体单体出现频率呈非随机改变,转化细胞为67％,逆转细胞仅占27％。提示丁酸对转化细胞的影响可能涉及生化物质的代谢和基因的调控。

The MNNG transformed Syrian hamster lung fibroblast cell line (BHLB4) established in our laboratory was treated with 2.0 mmol/L butyric acid. We obtained a butyric acid-dependent partially reversed cell line (ButB4) similar to normal cells in morphology, membrane properties, proliferation rate, colony-forming ability on solid agar culture, etc. However, when transplanted into nude mice, this cell line's tumorigenicity remained intact. Detection of cAMP levels in the cytoplasm showed much higher levels in ButB4 cells than in transformed cells.Butyric acid activity is evidently associated with changes of cAMP. In addition to phenotypical analysis, the karyotypes of ButB4 and BHLB4 were analyzed in detail. It was found that the disomy rate of C15 was significantly increased in ButB4 cells (73%) as compared with BHLB4 cells (33%). These results show that butyric acid not only induces phenotypic reversion in BHLB4 cells directly, but can also selectively kill C15 monos-omy cell clones, allowing rapid growth of C15 disomy cell clones. Butyric acid may also influence maintenance of the reversion phenotype.