GROWTH MODULATION AND ANALYSIS OF CHEMICALLY INDUCED TUMORS

我们已经开发了一种小鼠模型系统，其中快速化学诱导 肺腺癌和T细胞淋巴瘤使我们能够研究肺 致癌作用，并测试潜在的对策。 肿瘤是 在NFS x AKR小鼠中通过经胎盘注射 妊娠第16天使用I-乙基-L-亚硝基脲。 肿瘤促进 丁羟甲苯几乎一半的潜伏期为这些 导致大约90%的动物死于 在5到14周的年龄。 正常大小的Raf-I蛋白和RNA是 在所有的肿瘤中都有很高的表达，我们已经发现， 这些肿瘤中raf-1基因外显子15内的点突变。 为 因此，我们开始分析raf-1基因在人类肿瘤中的作用 点突变的样本。 对11对配对（正常与 肿瘤）的人DNA样品表明，4个肺肿瘤DNA含有 在异源双链体测定中具有改变的迁移率的产物。 序列分析 的1显示了邻近外显子14剪接供体的C到A颠换。 此外，我们还在多种小鼠中检测了raf家族RNA， 组织，以确定正常的表达模式。 用纯化的raf蛋白（专利）接种致癌物处理的小鼠 pending）之前被证明可以有效地消除提升阶段 肿瘤的发展。 然而，这种肿瘤的免疫学基础 调制是不清楚的，我们正在实施实验， 表达raf的重组牛痘病毒和表达raf的同基因细胞 不同形式的Raf-1来描述宿主反应。 希望这 将导致免疫原性表位的鉴定， 设计更有效的抗肿瘤疫苗方案。

We have developed a mouse model system in which rapid chemical induction of lung adenocarcinomas and T-cell lymphomas allows us to study lung carcinogenesis in vivo, and test potential countermeasures. Tumors are induced in NFS x AKR mice by transplacental injection of I-ethyl-l-nitrosourea on day 16 of gestation. Tumor promotion by butylated hydroxytoluene nearly halves the latency period for these tumors and results in approximately 90 percent of animals succumbing within 5 to 14 weeks of age. Normal-sized Raf-I protein and RNA are expressed at very high levels in all of the tumors and we have identified point mutations within exon 15 of the raf-1 gene in these tumors. For this reason we have begun to analyze the raf-I gene in human tumor samples for point mutations. An analysis of 11 paired (normal versus tumor) samples of human DNA indicated that 4 lung tumor DNAs contained products with altered mobility in heteroduplex assays. Sequence analysis of 1 revealed a C to A transversion adjacent to the exon 14 splice donor. In addition, we have examined raf family RNAs in a variety of mouse tissues in order to define normal expression patterns. Vaccination of carcinogen-treated mice with purified raf protein (patent pending) was previously shown to effectively eliminate the promoted phase of tumor development. However, the immunological basis for this tumor modulation is unclear, and we are implementing experiments using recombinant raf-expressing vaccinia virus and syngeneic cells expressing different forms of Raf-1 to delineate the host response. Hopefully this will lead to the identification of an immunogenic epitope(s) and enable us to design more effective anti-tumor vaccination regimens.