吸烟者肺肿瘤ras原癌基因活化的检测

THE DETECTION OF RAS PROTOONCOGENE ACTIVATED IN HUMAN LUNG TUMORS FROM SMOKERS

从有长期吸烟嗜好的肺癌患者的手术标本（鳞状上皮癌）提取高分子量的癌细胞基因组DNA，对小鼠成纤维细胞（NIH／3T3）进行转染，获二轮转化细胞，发现二轮转化率是一轮的3倍．证实在转染过程中转化灶出现的多少，与所用DNA的量有关，二轮转化细胞可在软琼脂上培养存活，接种裸鼠（BALB／c）于注射部位长出肿瘤。表明该二轮转化细胞具有肿瘤细胞的特性，用32P标记的人Alu重复序列和ras癌基因家族探针分别与一轮、二轮转化细胞和裸鼠肿瘤细胞的DNA进行Southern印迹转移和分子杂交。结果在三者细胞的DNA中都见有与Alu杂交的阳性条带，从而证明在转染过程中人体特有的Alu重复序列已整合到转化细胞的基因组中，并确定了转化细胞中的转化基因之一的属性为Ha－ras癌基因，本工作提示吸烟可能是人体原癌基因（C－Ha－ras）活化和肺鳞癌发生的重要原因。

High molecular weight genomic total DNA was extracted from the surgical samples ofhuman lung squamous cell carcinoma in patients with the habit of smoking. All were nottreated by chemotherapy. The two-round transfection tests were carried out with NIH/3T3cell system.The second round transformation was 3.0 times as efficient as that of the firstone. It seemed that the number of transforming focus increased with the amount of DNAused. The second round transforming cells were cultured alive in soft agar and implanted intonude mice(BALB/c). The tumor grew under the subcutaneous at injected site. It was showedthat the cells possessed the character of tumor cell. The DNA of the primary and secondarytransformed cells was analysed by Southern Blot with 32P labeled human Alu DNA sequenceand ras family gene as probes. The findings indicated that the positive bands hybridizingwith human Alu sequence were present in DNA extracted from the both transformed and thetumor cells from nude mice. It was identified that human lung carcinoma genomic DNA wasintegrated into these cells. And Ha-ras gene was considered as the putative transforming se-quence in relation with smoking.