Zimmerman R J, Cerutti P A
Department of Pharmacology, Cetus Corporation, Emeryville, CA 94608.
Mutat Res. 1988 Jun;199(2):449-59. doi: 10.1016/0027-5107(88)90221-7.
We have investigated the sensitivity to oncogenic transformation by an origin-defective SV40-containing plasmid, '8-16' (ori-SV40), of skin fibroblasts from normal individuals (NF), and from patients with 2 hereditary diseases characterized by an increased cancer risk, Bloom's syndrome (BS) and Fanconi's anemia (FA). It was hypothesized that perhaps these cells had already undergone some stage, or stages, of the progression to neoplasia, and that as a consequence of these changes, one could observe differential expression of characteristics of the transformed phenotype in these cells compared to normal, or perhaps they would behave differently in vivo. The data showed that FA cells and NF possessed comparable sensitivities to transformation by ori-SV40 DNA transfection, as measured either by focus formation above a confluent monolayer, or anchorage-independent growth. The BS cells, on the other hand, were 5-10 times less sensitive to this method of transformation, and further, the transformed phenotype was unstable. The resistance of BS cells to transformation by the 8-16 plasmid may be a reflection of their inherent genetic instability which affects stable integration and expression of the transfected plasmid DNA, since no differences in initial uptake of transfected DNA were observed between the various cell strains. Immortality and tumorigenicity were not readily demonstrated in this ori-SV40 transformation model. The results are discussed in relationship to the characteristics of the transformed phenotype of chemically treated normal human fibroblasts. SV40, an agent known to transform human cells, can be cast in a positive control role with respect to the appropriateness of the assays, the frequency of appearance of various markers, immortality and tumorigenicity. The tumorigenicity results are further compared to results obtained during the establishment of a wide range of fresh human tumor biopsies as xenograft lines in athymic nude mice, with particular emphasis on the sarcoma data.
我们研究了来自正常个体（NF）以及患有两种以癌症风险增加为特征的遗传性疾病——布卢姆综合征（BS）和范可尼贫血（FA）患者的皮肤成纤维细胞，对含原点缺陷的SV40质粒“8 - 16”（ori - SV40）致癌转化的敏感性。据推测，或许这些细胞已经经历了肿瘤形成进程的某个阶段或多个阶段，并且由于这些变化，与正常细胞相比，在这些细胞中可能会观察到转化表型特征的差异表达，或者它们在体内的行为可能会有所不同。数据显示，通过ori - SV40 DNA转染来衡量，FA细胞和NF对转化具有相当的敏感性，这可通过汇合单层上方的集落形成或不依赖贴壁生长来测定。另一方面，BS细胞对这种转化方法的敏感性低5 - 10倍，而且，转化后的表型不稳定。BS细胞对8 - 16质粒转化的抗性可能反映了其固有的遗传不稳定性，这种不稳定性影响了转染质粒DNA的稳定整合和表达，因为在各种细胞株之间未观察到转染DNA初始摄取的差异。在这个ori - SV40转化模型中，永生性和致瘤性并不容易被证实。结合化学处理的正常人成纤维细胞转化表型的特征对结果进行了讨论。SV40是一种已知可转化人类细胞的因子，就检测方法的适用性、各种标志物出现的频率、永生性和致瘤性而言，它可起到阳性对照的作用。将致瘤性结果进一步与在无胸腺裸鼠中建立广泛的新鲜人类肿瘤活检异种移植系期间获得的结果进行比较，特别强调肉瘤数据。
