Hsiung Y, Jannatipour M, Rose A, McMahon J, Duncan D, Nitiss J L
Division of Hematology/Oncology, Childrens Hospital, Los Angeles, California 90027, USA.
Cancer Res. 1996 Jan 1;56(1):91-9.
DNA topoisomerase II is the target of a variety of important antitumor agents, including etoposide, adriamycin, and amsacrine. We have constructed a system for analyzing the action of anti-topoisomerase II agents using the yeast Saccharomyces cerevisiae and have constructed vectors for expressing human topoisomerase II functionally in yeast. We have demonstrated that temperature-conditional yeast TOP2 mutants can be complemented by expression of wild-type human topoisomerase II alpha. Furthermore, expression of human topoisomerase II in yeast results in a quantitatively unique pattern of sensitivity to amsacrine. We also have constructed mutations in human TOP2 based on previously identified mutations from a human cell line selected for resistance to teniposide. Our experiments demonstrate that mutation of either arginine 450 or proline 803 of human topoisomerase II can result in an enzyme that has altered sensitivity to anti-topoisomerase II agents, and that a human enzyme carrying both mutations confers a higher level of drug resistance than enzymes carrying either single mutation.
DNA拓扑异构酶II是包括依托泊苷、阿霉素和安吖啶在内的多种重要抗肿瘤药物的作用靶点。我们构建了一个利用酿酒酵母分析抗拓扑异构酶II药物作用的系统，并构建了在酵母中功能性表达人拓扑异构酶II的载体。我们已经证明，温度条件性酵母TOP2突变体可以通过野生型人拓扑异构酶IIα的表达得到互补。此外，人拓扑异构酶II在酵母中的表达导致对安吖啶的敏感性呈现出定量上独特的模式。我们还根据先前从对替尼泊苷耐药的人细胞系中鉴定出的突变，在人TOP2中构建了突变体。我们的实验表明，人拓扑异构酶II的精氨酸450或脯氨酸803发生突变，可导致酶对抗拓扑异构酶II药物的敏感性发生改变，且同时携带这两种突变的人酶比携带任一单突变的酶具有更高水平的耐药性。
