Lage H, Helmbach H, Grottke C, Dietel M, Schadendorf D
Institute of Pathology, Charité, Campus Mitte, Humboldt University Berlin, Germany.
FEBS Lett. 2001 Apr 6;494(1-2):54-9. doi: 10.1016/s0014-5793(01)02304-3.
Resistance to drug treatment is a common observation in malignant melanoma. In order to analyze alterations in mRNA expression profiles associated with drug resistance in melanoma cells we previously established a panel of various drug-resistant cell variants derived from the human melanoma line MeWo and compared the mRNA expression profiles by a differential display technique. By that approach it could be demonstrated that the expression level of a mRNA encoded by a gene found to be mutated in non-syndromic hearing impairment, DFNA5 (ICERE-1), was distinctly decreased in the 33-fold etoposide-resistant melanoma cell line MeWo ETO 1. To evaluate the hypothesis that a decrease in DFNA5 mRNA expression level contributes to the acquired etoposide resistance phenotype exhibited by MeWo ETO 1 cells, this drug-resistant line was stably transfected with the DFNA5-encoding cDNA. Transfected clones showed a 30-35% reduced etoposide susceptibility by comparing the IC(25), IC(50) and IC(75) values of these clones with those displayed by the non-transfected, etoposide-resistant melanoma cell line MeWo ETO 1 and controls. Furthermore, etoposide exposure of stable DFNA5 transfectants resulted in an increase of caspase-3-mediated apoptotic events in DFNA5-transfected clones in comparison to MeWo ETO 1 cells and controls. The data therefore demonstrate that a decrease in DNFA5 mRNA expression level is associated with an increased etoposide resistance in melanoma cells due to an elevated cellular susceptibility to trigger a caspase-3-depending signal pathway leading to programmed cell death.
对药物治疗产生耐药性是恶性黑色素瘤中常见的现象。为了分析与黑色素瘤细胞耐药性相关的mRNA表达谱变化，我们先前建立了一组源自人黑色素瘤细胞系MeWo的各种耐药细胞变体，并通过差异显示技术比较了mRNA表达谱。通过该方法可以证明，在非综合征性听力损失中发现的一个基因（DFNA5，即ICERE-1）编码的mRNA表达水平，在33倍耐依托泊苷的黑色素瘤细胞系MeWo ETO 1中明显降低。为了评估DFNA5 mRNA表达水平降低导致MeWo ETO 1细胞呈现获得性依托泊苷耐药表型这一假说，用编码DFNA5的cDNA稳定转染该耐药细胞系。通过比较这些克隆的IC(25)、IC(50)和IC(75)值与未转染的耐依托泊苷黑色素瘤细胞系MeWo ETO 1及对照所显示的值，发现转染后的克隆对依托泊苷的敏感性降低了30 - 35%。此外，与MeWo ETO 1细胞及对照相比，稳定转染DFNA5的细胞系经依托泊苷处理后，DFNA5转染克隆中caspase-3介导的凋亡事件增加。因此，数据表明，DNFA5 mRNA表达水平降低与黑色素瘤细胞中依托泊苷耐药性增加有关，这是由于细胞对触发依赖caspase-3的信号通路导致程序性细胞死亡的敏感性增加所致。
