Allenhoffmann B, Schlosser S, Rhim J
NCI,CELLULAR & MOLEC BIOL LAB,BETHESDA,MD 20892.
Int J Oncol. 1993 Oct;3(4):619-25. doi: 10.3892/ijo.3.4.619.
We report here the use of a nontumorigenic, immortalized human keratinocyte line, RHEK-1, for the detection of rare mutations induced at the hypoxanthine-guanine phosphoribosyltransferase locus. RHEK-1 keratinocytes were used as a prototype to determine mutagen treatment conditions, plating density, and phenotypic expression time for maximum recovery of thioguanine-resistant mutants. Mutation frequency was measured after exposure to ionizing radiation or to polycyclic aromatic hydrocarbons. 7,12-Dimethylbenz[a]-anthracene and benzo[a]pyrene caused almost no cytotoxicity, but induced thioguanine-resistant mutants at frequencies as much as 30 to 40-fold higher than the median spontaneous frequency of 7 x 10(-6). X-irradiation was also an efficient mutagen in RHEK-1 keratinocytes. The mutants were aminopterin-sensitive and possessed no measurable hypoxanthine-guanine phosphoribosyltransferase activity. The RHEK-1 human epithelial cell line is therefore useful for the study of induced mutation at a defined genetic locus as well as being an important model for the investigation, of molecular, cellular and genetic mechanisms of neoplastic transformation in human stratified squamous epithelia.
我们在此报告使用一种非致瘤性的永生化人角质形成细胞系RHEK-1，用于检测次黄嘌呤-鸟嘌呤磷酸核糖转移酶基因座处诱导的罕见突变。RHEK-1角质形成细胞被用作原型，以确定诱变处理条件、接种密度和表型表达时间，以最大程度地回收硫代鸟嘌呤抗性突变体。在暴露于电离辐射或多环芳烃后测量突变频率。7,12-二甲基苯并[a]蒽和苯并[a]芘几乎没有细胞毒性，但诱导硫代鸟嘌呤抗性突变体的频率比7×10⁻⁶的中位自发频率高30至40倍。X射线照射在RHEK-1角质形成细胞中也是一种有效的诱变剂。这些突变体对氨基蝶呤敏感，且不具有可测量的次黄嘌呤-鸟嘌呤磷酸核糖转移酶活性。因此，RHEK-1人上皮细胞系可用于研究特定基因座处的诱导突变，也是研究人复层鳞状上皮细胞肿瘤转化的分子、细胞和遗传机制的重要模型。
