Gao Z, Gao Z, Fields J Z, Boman B M
Cancer Research Laboratory, CA*TX, Inc., Omaha, NE 68103, USA.
Anticancer Res. 1998 Jul-Aug;18(4C):3073-6.
The resistance of lung cancer cells to the therapeutic actions of anticancer drugs is a serious clinical problem often encountered during cancer chemotherapy. It is very important, therefore, to investigate how to prevent and/or reverse this drug resistance. To this end, we took advantage of the fact that the overexpression of MDR1 and MRP genes, two genes known to be associated with the development of drug resistance, is very common in lung cancer. We used antisense RNA in an attempt to prevent expression of the protein products of these genes. Using a retrovirus, we introduced the antisense RNAs of MDR1 and MRP genes into doxorubicin-selected, multidrug-resistant GAOK cells, a cell which overexpresses both MDR1 and MRP genes. The expression levels of the products of the MDR1 gene (Pgp) and MRP gene (Mrp) in the transfected cells were analyzed using flow cytometry, and the drug resistances of the transfected cells were detected by a cell viability (MTT) assay. The expression of Pgp and Mrp in the transfected cells was almost completely inhibited by the antisense RNAs: expression levels decreased 64% and 93%, respectively. In parallel, the drug resistance of these cells decreased about 99% to doxorubicin, 98% to vinblastine, and 97% to colchicine. These results show that: a) antisense RNAs can attenuate drug resistance, an inhibition that might lead to new treatments for patients who are, or become, refractory to conventional chemotherapy; b) MDR1 and MRP appear to be cooperating to confer drug resistance in GAOK cells.
肺癌细胞对抗癌药物治疗作用的耐药性是癌症化疗中经常遇到的严重临床问题。因此，研究如何预防和/或逆转这种耐药性非常重要。为此，我们利用了这样一个事实，即MDR1和MRP基因的过表达在肺癌中非常普遍，这两个基因已知与耐药性的产生有关。我们使用反义RNA试图阻止这些基因的蛋白质产物的表达。利用逆转录病毒，我们将MDR1和MRP基因的反义RNA导入经阿霉素筛选的多药耐药GAOK细胞中，该细胞同时过表达MDR1和MRP基因。使用流式细胞术分析转染细胞中MDR1基因产物（Pgp）和MRP基因产物（Mrp）的表达水平，并通过细胞活力（MTT）测定法检测转染细胞的耐药性。转染细胞中Pgp和Mrp的表达几乎完全被反义RNA抑制：表达水平分别下降了64%和93%。与此同时，这些细胞对阿霉素的耐药性下降了约99%，对长春碱的耐药性下降了98%，对秋水仙碱的耐药性下降了97%。这些结果表明：a）反义RNA可以减弱耐药性，这种抑制作用可能会为那些对传统化疗难治或变得难治的患者带来新的治疗方法；b）MDR1和MRP似乎共同作用赋予GAOK细胞耐药性。
