STUDIES ON THE ACTIVATED FORM OF THE HUMAN PROTO-ONCOGENE, C-HA-RAS

我们已经将各种病毒和细胞癌基因导入到 大鼠胚胎细胞的原代培养，并获得了 形态转化的细胞。使用RAS进行转换 单独观察到致癌基因；然而，在 得到了ras的转化频率 与腺病毒E1a基因共转染。我们已经检查了 Ras癌基因单独转化和ras+转化的细胞系 E1a，并观察到它们在转移方面的显著差异 在裸鼠身上进行的潜伏期测定。具体地说，仅RAS 转化子具有高度的转移性，而这两个基因 转化子显示出非常低的转移潜力。转染法 而不是血清12型E1a基因，转化为 仅RAS转化子就导致大幅减少(在 这些细胞系的转移潜能至少提高了10倍。 目前正在进行实验，通过以下方式研究这种机制 哪种腺病毒2型E1a基因可减少转移 仅ras转化子的潜力。此外，我们还有 构建了两个高转移性和高转移性的cDNA库 低转移细胞系。将对这些库进行筛选 CDNAs探针，以分离唯一或 在任一细胞系中优先表达。

We have transfected various viral and cellular oncogenes into primary cultures of rat embryo cells and have obtained lines of morphologically transformed cells. Transformation with the ras oncogene alone was observed; however, a 10-fold increase in the transformation frequency was obtained when ras was cotransfected with the adenovirus E1A gene. We have examined cell lines transformed by the ras oncogene alone, and by ras plus E1A and have observed a striking difference in their metastatic potential as assayed in nude mice. Specifically, the ras alone transformants are highly metastatic, while the two gene transformants show a very low metastatic potential. Transfection of serotype 2 E1A gene, but not the serotype 12 E1A gene, into the ras alone transformants results in a substantial reduction (at least 10-fold) in the metastatic potential of these cell lines. Experiments are in progress to investigate the mechanism by which the adenovirus type 2 E1A gene reduces the metastatic potential of the ras alone transformants. In addition, we have constructed two cDNA libraries from both a high metastatic and a low metastatic cell line. These libraries will be screened with cDNA probes in order to isolate genes that are uniquely or preferentially expressed in either cell line.