Shou J, Zhang Y, Wu D
Institute of Radiation Medicine, Beijing 100850.
Chin Med Sci J. 1997 Mar;12(1):6-10.
Syrian hamster embryo (SHE) cells are irradiated by alpha particles emitted from Plutonium-238 in vitro. Transfection frequencies of donor DNA derived from passaged cells, including monocloned cells from 20th passage cells, after irradiation are parallel with their tumorigenicity of donor cells. After transformation, expressions of H-ras and c-myc genes are in the state of activation, which might be resulted from occurrence of mutation in H-ras gene and hypomethylation of c-myc gene respectively, even though no alteration was observed on their restriction fragment length polymorphisms (RELP) patterns of both genes. On the other hand, expression of p53 gene is also found to be in the state of activation in transformant, but no heavy staining of p53 protein appeared in the transformant-derived tumor with p53 specific McAb HD 200. This might be result from the partial deletion of p53 cDNA in transformant by reverse transcriptional polymerase chain reaction (RT-PCR). These results imply that activation of H-ras and c-myc genes coupled with inactivation of p53 tumor suppressor gene play important role in alpha particle-induced cell transformation.
叙利亚仓鼠胚胎（SHE）细胞在体外受到钚-238发射的α粒子照射。照射后，来自传代细胞（包括第20代细胞的单克隆细胞）的供体DNA的转染频率与其供体细胞的致瘤性平行。转化后，H-ras和c-myc基因的表达处于激活状态，这可能分别是由于H-ras基因发生突变和c-myc基因低甲基化所致，尽管在这两个基因的限制性片段长度多态性（RELP）模式上未观察到改变。另一方面，在转化体中也发现p53基因的表达处于激活状态，但用p53特异性单克隆抗体HD 200在转化体衍生的肿瘤中未出现p53蛋白的重染色。这可能是由于通过逆转录聚合酶链反应（RT-PCR）转化体中p53 cDNA部分缺失所致。这些结果表明，H-ras和c-myc基因的激活以及p53肿瘤抑制基因的失活在α粒子诱导的细胞转化中起重要作用。
