Taya Y, Hosogai K, Hirohashi S, Shimosato Y, Tsuchiya R, Tsuchida N, Fushimi M, Sekiya T, Nishimura S
EMBO J. 1984 Dec 1;3(12):2943-6. doi: 10.1002/j.1460-2075.1984.tb02236.x.
Amplifications of two oncogenes, c-K-ras-2 and c-myc, were found in a human lung giant cell carcinoma (LGCC) Lu-65, which is maintained in nude mice. The extent of c-K-ras-2 and myc amplifications were estimated to be 10- and 8-fold, respectively, by means of the Southern hybridization procedure. In addition, NIH3T3 cells were transformed by transfection of Lu-65 DNA and the transforming gene was identified as c-K-ras-2. c-K-ras-2 genes were cloned from a gene library of Lu-65 and a single point mutation causing a substitution of cysteine for glycine in codon 12 was found by DNA sequencing. It was concluded that the amplification of the c-myc and c-K-ras-2 genes are accompanied by point mutational activation of c-K-ras-2 in the human LGCC Lu-65. This is the first report of multiple gene amplification accompanied by a point mutation of oncogenes in human cancer cells, providing further support for the idea that co-operation of at least two activated cellular oncogenes is required for carcinogenesis.
在一只裸鼠体内传代培养的人肺巨细胞癌（LGCC）Lu-65中，发现了两种致癌基因c-K-ras-2和c-myc的扩增。通过Southern杂交法估计，c-K-ras-2和myc的扩增程度分别为10倍和8倍。此外，用Lu-65 DNA转染NIH3T3细胞可使其发生转化，并且确定转化基因就是c-K-ras-2。从Lu-65的基因文库中克隆出c-K-ras-2基因，经DNA测序发现，在第12密码子处有一个导致甘氨酸被半胱氨酸取代的单点突变。得出的结论是，在人肺巨细胞癌Lu-65中，c-myc和c-K-ras-2基因的扩增伴随着c-K-ras-2的点突变激活。这是关于人类癌细胞中多个基因扩增并伴有致癌基因点突变的首次报道，进一步支持了致癌过程需要至少两个激活的细胞致癌基因协同作用这一观点。
