Attenuated topoisomerase II content directly correlates with a low level of drug resistance in a Chinese hamster ovary cell line.
Attenuated topoisomerase II content directly correlates with a low level of drug resistance in a Chinese hamster ovary cell line.
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发表时间：
1991-12
期刊：
影响因子：
11.2
通讯作者：
Charles D. Webb;M. D. Latham;Richard B. Lock;D. M. Sullivan
中科院分区：
文献类型：
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作者：
Charles D. Webb;M. D. Latham;Richard B. Lock;D. M. Sullivan
一种新的多重耐药中国仓鼠卵巢细胞系CHO-SMR5的分离表明，细胞拓扑异构酶II活性降低（降低5倍）与拓扑异构酶II抑制剂的低水平耐药（3- 7倍）之间存在直接关系。该细胞系最初被选择为对9-（4,6- o -乙基- β -d -葡萄糖吡喃基）-4'-去甲基甲磷脂酰素具有抗性，对其他拓扑异构酶II抑制剂，包括4'-（9-吖啶胺）甲磺酸-m-氨基苯胺、阿霉素和米托蒽醌具有交叉抗性。免疫印迹法显示，与野生型细胞相比，耐药细胞的拓扑异构酶II降低了4.5倍。药物摄取研究表明，在抗性细胞和亲本细胞中，[3H]9-（4,6- o -乙基- β -d -葡萄糖吡喃基）-4'-去甲基哌替啶毒素的平衡浓度相当。与野生型中国仓鼠卵巢细胞相比，耐药细胞系中拓扑异构酶II（动质体DNA十烯二化）的催化活性降低了5倍。药物引起的DNA损伤，以DNA双链断裂的形成或共价DNA-酶复合物的形成来衡量，在耐药细胞系中减少了4倍。最后，Northern blot分析显示，从对数期CHO-SMR5细胞中分离的拓扑异构酶II mRNA减少了5倍。这些发现表明，拓扑异构酶II水平的降低可能是这种新型细胞系耐药的唯一机制。
A new multiple drug-resistant Chinese hamster ovary cell line, CHO-SMR5, has been isolated which demonstrates a direct correlation between reduced cellular topoisomerase II activity (5-fold reduction) and a low level of resistance (3- to 7-fold) to topoisomerase II inhibitors. This cell line, initially selected for resistance to 9-(4,6-O-ethylidene-beta-D-glucopyranosyl)-4'-demethylepipodophylloto xin, exhibits cross-resistance to other topoisomerase II inhibitors including 4'-(9-acridinylamino)methanesulfon-m-anisidide, doxorubicin, and mitoxantrone. The resistant cells show a 4.5-fold decrease in topoisomerase II by immunoblotting when compared to wild-type cells. Drug uptake studies reveal equivalent equilibrium intracellular concentrations of [3H]9-(4,6-O-ethylidene-beta-D-glucopyranosyl)-4'-demethyepipodophyll otoxin in the resistant and parental cells. The catalytic activity of topoisomerase II (decatenation of kinetoplast DNA) is 5-fold less in the drug-resistant cell line relative to wild-type Chinese hamster ovary cells. Drug-induced DNA damage, measured as either formation of DNA double-strand breaks or covalent DNA-enzyme complexes, is 4-fold less in the resistant cell line. Finally, Northern blot analysis demonstrates a 5-fold reduction in topoisomerase II mRNA isolated from log phase CHO-SMR5 cells. These findings suggest that a reduced level of topoisomerase II is likely to be the sole mechanism of drug resistance in this novel cell line.