Ananthaswamy H N, Price J E, Goldberg L H, Bales E S
Department of Immunology, University of Texas M.D. Anderson Hospital and Tumor Institute, Houston.
Cancer Res. 1988 Jun 15;48(12):3341-6.
High-molecular-weight DNA isolated from eight fresh human skin cancers occurring on sun-exposed body sites were assayed for their ability to transform NIH 3T3 cells. A cotransfection protocol using pSV2-neo DNA, which confers resistance to the antibiotic G418, was used to select cells that had taken up the transfected DNA. About 2 weeks after transfection, G418-resistant colonies were pooled and injected s.c. into athymic nude mice. The NIH 3T3 cells transfected with DNA from six of the human skin cancers induced tumors in nude mice. DNAs from all six tumor cell lines contained human alu sequences. Southern blot hybridization with ras-specific probes revealed that DNAs from the four alu-rich tumors contained the human Ha-ras oncogene, in addition to that of the NIH 3T3 controls. In contrast, DNAs from the other two tumors did not contain any of the known oncogenes tested, except those endogenous to NIH 3T3 cells. DNAs from three of four first cycle tumorigenic transformants gave rise to morphologically transformed foci when assayed in a second cycle of transfection. DNAs from all three secondary transformants contained discrete human alu sequences, and in addition, contained Ha-ras sequences similar to those present in their respective primary transformants. Interestingly, DNA from both primary and secondary transformants of one particular human squamous cell carcinoma contained highly amplified copies of the Ha-ras oncogene. These results suggest that activation of the Ha-ras oncogene may be common in human skin cancers originating on sun-exposed body sites. Further characterization of the Ha-ras oncogenes present in these human skin cancers may provide information on the molecular mechanisms by which UV radiation of the sun induces human neoplasms on exposed body sites.
从八个发生在身体暴露于阳光部位的新鲜人类皮肤癌中分离出高分子量DNA，检测其转化NIH 3T3细胞的能力。使用赋予对抗生素G418抗性的pSV2-neo DNA的共转染方案来选择摄取了转染DNA的细胞。转染后约2周，将对G418有抗性的菌落汇集并皮下注射到无胸腺裸鼠体内。用来自六种人类皮肤癌的DNA转染的NIH 3T3细胞在裸鼠中诱导出肿瘤。所有六种肿瘤细胞系的DNA都含有人类alu序列。用ras特异性探针进行的Southern印迹杂交显示，除了NIH 3T3对照的序列外，来自四个富含alu的肿瘤的DNA还含有人类Ha-ras癌基因。相比之下，来自其他两个肿瘤的DNA除了NIH 3T3细胞内源性的那些基因外，不包含任何所检测的已知癌基因。在第二轮转染检测时，来自四个第一轮致瘤转化体中的三个的DNA产生了形态转化灶。来自所有三个第二代转化体的DNA都含有离散的人类alu序列，此外，还含有与其各自第一代转化体中存在的类似的Ha-ras序列。有趣的是，来自一种特定人类鳞状细胞癌的第一代和第二代转化体的DNA都含有高度扩增的Ha-ras癌基因拷贝。这些结果表明，Ha-ras癌基因的激活在起源于身体暴露于阳光部位的人类皮肤癌中可能很常见。对这些人类皮肤癌中存在的Ha-ras癌基因的进一步表征可能会提供有关阳光紫外线辐射在暴露身体部位诱导人类肿瘤的分子机制的信息。
