Long Jason, Manchandia Tejas, Ban Kechen, Gao Shan, Miller Claudia, Chandra Joya
Department of Pediatrics Research, Division of Pediatrics, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., 853, Houston, TX 77030, USA.
Cancer Chemother Pharmacol. 2007 Mar;59(4):527-35. doi: 10.1007/s00280-006-0295-5. Epub 2006 Aug 19.
To delineate a role for reactive oxygen species (ROS) induction in adaphostin-induced apoptosis in glioblastoma cells.
Three glioblastoma cell lines with different sensitivities to adaphostin were characterized for sensitivity to an oxidant, tert-butyl hydroperoxide. The degree and duration of the ROS levels was assessed in the three cell lines after adaphostin exposure. Antioxidant protein levels were evaluated by Western blotting.
Of the three glioblastoma cell lines, the U87 cells were least sensitive to adaphostin. These cells were also least sensitive to tert-butyl hydroperoxide, indicating that sensitivity to a direct oxidant stress mirrors the cells' adaphostin sensitivities. In addition, the antioxidant N-acetylcysteine, (NAC) was protective against adaphostin-induced apoptosis. Direct measurement of intracellular peroxides showed a transient increase in the two less sensitive cell lines (U87 and LN18) which diminishes by 24 h. In contrast, U251 cells, which are most sensitive to adaphostin, display a sustained increase in the ROS levels. After the initial increase in intracellular peroxides, the heat shock protein and antioxidant heme oxygenase-1 (HO-1) was upregulated. Levels of other antioxidant proteins, such as catalase and thioredoxin, however, were not altered by adaphostin in glioblastoma cell lines. NAC attenuated HO-1 upregulation, confirming the time course analysis.
These results suggest a primary role for ROS in adaphostin-induced apoptosis in glioblastoma. Our data indicate that the duration of intracellular ROS levels is a key factor in mediating sensitivity to adaphostin. Furthermore, upregulation of HO-1 is a novel molecular marker of adaphostin's action. The kinetics with which adaphostin upregulates HO-1 correlates with sensitivity to the drug. Taken together, our data indicate that a cell's ability to cope with ROS dictates sensitivity to adaphostin and conceivably other chemotherapies that cause redox perturbations.
阐明活性氧（ROS）诱导在阿地福司汀诱导的胶质母细胞瘤细胞凋亡中的作用。
对三种对阿地福司汀敏感性不同的胶质母细胞瘤细胞系进行对氧化剂叔丁基过氧化氢的敏感性鉴定。在阿地福司汀暴露后，评估这三种细胞系中ROS水平的程度和持续时间。通过蛋白质免疫印迹法评估抗氧化蛋白水平。
在这三种胶质母细胞瘤细胞系中，U87细胞对阿地福司汀最不敏感。这些细胞对叔丁基过氧化氢也最不敏感，表明对直接氧化应激的敏感性反映了细胞对阿地福司汀的敏感性。此外，抗氧化剂N-乙酰半胱氨酸（NAC）对阿地福司汀诱导的凋亡具有保护作用。细胞内过氧化物的直接测量显示，两种较不敏感的细胞系（U87和LN18）中过氧化物有短暂增加，到24小时时减少。相比之下，对阿地福司汀最敏感的U251细胞系中ROS水平持续升高。在细胞内过氧化物最初增加后，热休克蛋白和抗氧化血红素加氧酶-1（HO-1）上调。然而，其他抗氧化蛋白如过氧化氢酶和硫氧还蛋白的水平在胶质母细胞瘤细胞系中未被阿地福司汀改变。NAC减弱了HO-1的上调，证实了时间进程分析。
这些结果表明ROS在阿地福司汀诱导的胶质母细胞瘤细胞凋亡中起主要作用。我们的数据表明细胞内ROS水平的持续时间是介导对阿地福司汀敏感性的关键因素。此外，HO-1的上调是阿地福司汀作用的一个新的分子标志物。阿地福司汀上调HO-1的动力学与对该药物的敏感性相关。综上所述，我们的数据表明细胞应对ROS的能力决定了对阿地福司汀以及其他可能导致氧化还原扰动的化疗药物的敏感性。
