Baker Amanda F, Landowski Terry, Dorr Robert, Tate Wendy R, Gard Jaime M C, Tavenner Breonna E, Dragovich Tomislov, Coon Amy, Powis Garth
University of Arizona Cancer Center, Tucson, Arizona 85724, USA.
Clin Cancer Res. 2007 Jun 1;13(11):3388-94. doi: 10.1158/1078-0432.CCR-06-0873.
The aim of this study was to identify biomarkers that may be predictive for the clinical activity of the redox-active antitumor agent imexon.
cDNA microarray and quantitative real-time PCR were used to identify global changes in gene expression in peripheral blood mononuclear cells (PBMC) collected from patients treated with imexon during a phase I trial. Electrophoretic mobility shift assays and Western blot analysis were done using the RPMI8226 myeloma cell line grown in vitro and PBMCs treated ex vivo to investigate the molecular mechanism responsible for these gene changes.
Both cDNA microarray and quantitative real-time PCR showed the up-regulation of many antioxidant genes, including thioredoxin reductase-1, glutaredoxin-2, and peroxiredoxin-3 in PBMCs collected from patients treated with imexon. Studies in PBMCs treated ex vivo and RPMI8226 myeloma cells showed that imexon increased binding to the activator protein-1 consensus sequence measured by electrophoretic mobility shift assay. Supershift analysis showed that the majority of the activator protein-1 DNA binding activity was c-Jun, with minor contribution of Jun-D. Nuclear translocation of the nuclear factor (erythroid-derived 1)-like 2 transcription factor and its binding to the antioxidant response element was also increased after imexon treatment, which correlated with an increase in the message levels for nuclear factor (erythroid-derived 1)-like 2/antioxidant response element-regulated antioxidant genes.
Together, these results show that a predominant biological effect of imexon is a change in redox state that can be detected in surrogate normal tissues as increased redox-sensitive transcription factor binding and increased antioxidant gene expression.
本研究旨在鉴定可能预测氧化还原活性抗肿瘤药物艾美克生临床活性的生物标志物。
在一项I期试验中，利用cDNA微阵列和定量实时PCR来鉴定从接受艾美克生治疗的患者采集的外周血单个核细胞（PBMC）中基因表达的整体变化。使用体外培养的RPMI8226骨髓瘤细胞系和离体处理的PBMC进行电泳迁移率变动分析和蛋白质印迹分析，以研究导致这些基因变化的分子机制。
cDNA微阵列和定量实时PCR均显示，从接受艾美克生治疗的患者采集的PBMC中，许多抗氧化基因上调，包括硫氧还蛋白还原酶-1、谷氧还蛋白-2和过氧化物酶体增殖物激活受体-3。对离体处理的PBMC和RPMI8226骨髓瘤细胞的研究表明，艾美克生增加了通过电泳迁移率变动分析测定的与激活蛋白-1共有序列的结合。超迁移分析表明，激活蛋白-1的DNA结合活性主要是c-Jun，Jun-D的贡献较小。艾美克生处理后，核因子（红细胞衍生1）样2转录因子的核转位及其与抗氧化反应元件的结合也增加，这与核因子（红细胞衍生1）样2/抗氧化反应元件调节的抗氧化基因的信使水平增加相关。
总之，这些结果表明，艾美克生的主要生物学效应是氧化还原状态的改变，这可以在替代正常组织中检测到，表现为氧化还原敏感转录因子结合增加和抗氧化基因表达增加。
