Maheshwari K K, Parsa I
Department of Pathology, State University of New York Health Science Center, Brookyn 11203.
Biochem Int. 1991 Sep;25(2):233-40.
Amplification and activation of c-Ki-ras gene was studied in normal human pancreas and a cell line (T-3) derived from normal pancreas explants exposed to methylnitrosourea (MNU) for 26 weeks. Normal genomic DNAs from pancreas and derived cell lines showed no transforming activity in NIH 3T3 cells. However, DNAs isolated from tumorigenic cell line derived from MNU treated human pancreas explants transformed NIH 3T3 cells. The hybridization profiles showed that the c-Ki-ras gene was amplified 5 fold in the tumorigenic cells (T-3). The level of mRNA specific to the c-Ki-ras gene was found to be 50-60 fold higher in the malignant cells than in normal human pancreas. These results suggest that higher expression of ras genes is due to gene amplification and/or activation, which is an important step in carcinogenesis.
研究了正常人类胰腺以及从暴露于甲基亚硝基脲（MNU）26周的正常胰腺外植体衍生的细胞系（T-3）中c-Ki-ras基因的扩增和激活情况。来自胰腺和衍生细胞系的正常基因组DNA在NIH 3T3细胞中未显示出转化活性。然而，从经MNU处理的人类胰腺外植体衍生的致瘤细胞系中分离的DNA可转化NIH 3T3细胞。杂交图谱显示，致瘤细胞（T-3）中的c-Ki-ras基因扩增了5倍。发现c-Ki-ras基因特异性mRNA的水平在恶性细胞中比在正常人类胰腺中高50至60倍。这些结果表明，ras基因的高表达是由于基因扩增和/或激活，这是致癌过程中的一个重要步骤。
