Andringa Kelly K, Coleman Mitchell C, Aykin-Burns Nukhet, Hitchler Michael J, Walsh Susan A, Domann Frederick E, Spitz Douglas R
Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA.
Cancer Res. 2006 Feb 1;66(3):1605-10. doi: 10.1158/0008-5472.CAN-05-3462.
It has been hypothesized that cancer cells increase glucose metabolism to protect against metabolic fluxes of hydroperoxides via glutathione-dependent peroxidases. 2-Deoxy-D-glucose, inhibits glucose metabolism and has been shown to cause cytotoxicity in cancer cells that is partially mediated by disruptions in thiol metabolism. In the current study, human breast cancer cells were continuously treated (24 hours) with 2-deoxy-D-glucose, and total glutathione content as well as the expression of the first enzyme in the glutathione synthetic pathway [glutamate cysteine ligase (GCL)] were found to be induced 2.0-fold. Inhibiting GCL activity during 2-deoxy-D-glucose exposure using l-buthionine-[S,R]-sulfoximine (BSO) significantly enhanced the cytotoxic effects of 2-deoxy-D-glucose and caused increases in endpoints indicative of oxidative stress, including % oxidized glutathione and steady-state levels of pro-oxidants as assayed using an oxidation-sensitive fluorescent probe. These results show that treatment of human breast cancer cells with 2-deoxy-d-glucose causes metabolic oxidative stress that is accompanied by increases in steady-state levels of GCL mRNA, GCL activity, and glutathione content. Furthermore, inhibition of 2-deoxy-D-glucose-mediated induction of GCL activity with BSO increases endpoints indicative of oxidative stress and sensitizes cancer cells to 2-deoxy-D-glucose-induced cytotoxicity. These results support the hypothesis that drug combinations capable of inhibiting both glucose and hydroperoxide metabolism may provide an effective biochemical strategy for sensitizing human cancer cells to metabolic oxidative stress.
有假说认为，癌细胞会增加葡萄糖代谢，以通过谷胱甘肽依赖性过氧化物酶抵御氢过氧化物的代谢通量。2-脱氧-D-葡萄糖可抑制葡萄糖代谢，并已证明其在癌细胞中会引起细胞毒性，这种毒性部分是由硫醇代谢紊乱介导的。在本研究中，人乳腺癌细胞用2-脱氧-D-葡萄糖连续处理（24小时），发现总谷胱甘肽含量以及谷胱甘肽合成途径中的第一种酶[谷氨酸半胱氨酸连接酶（GCL）]的表达被诱导了2.0倍。在2-脱氧-D-葡萄糖暴露期间，使用L-丁硫氨酸-[S，R]-亚砜胺（BSO）抑制GCL活性，可显著增强2-脱氧-D-葡萄糖的细胞毒性作用，并导致氧化应激指标升高，包括使用氧化敏感荧光探针测定的氧化型谷胱甘肽百分比和促氧化剂的稳态水平。这些结果表明，用2-脱氧-D-葡萄糖处理人乳腺癌细胞会导致代谢性氧化应激，同时伴随着GCL mRNA、GCL活性和谷胱甘肽含量的稳态水平升高。此外，用BSO抑制2-脱氧-D-葡萄糖介导的GCL活性诱导会增加氧化应激指标，并使癌细胞对2-脱氧-D-葡萄糖诱导的细胞毒性敏感。这些结果支持了这样一种假说，即能够同时抑制葡萄糖和氢过氧化物代谢的药物组合可能为使人癌细胞对代谢性氧化应激敏感提供一种有效的生化策略。
