Manganese superoxide dismutase-mediated gene expression in radiation-induced adaptive responses
Manganese superoxide dismutase-mediated gene expression in radiation-induced adaptive responses
复制标题
DOI：
10.1128/mcb.23.7.2362-2378.2003
复制
发表时间：
2003-04-01
影响因子：
5.3
通讯作者：
Li, JJ
中科院分区：
文献类型：
--
作者：
Guo, GZ;Yan-Sanders, Y;Li, JJ
抗氧化酶在氧化应激反应中至关重要。分次电离辐射（MCF+FIR 细胞）或锰超氧化物歧化酶（MCF+SOD 细胞）过表达后从 MCF-7 人类癌细胞中分离出的放射抗性变体在 10% isosurvivall 下表现出剂量调节因子，分别为 1.8 和 2.3。 MCF+FIR 和 MCF-7 细胞（暴露于单剂量辐射）的 MnSOD 活性、mRNA 和免疫反应蛋白增加了 5 至 10 倍。表达反义 MnSOD 后，MCF+FIR 和 MCF+SOD 细胞的放射抗性降低。 DNA 微阵列分析和免疫印迹鉴定出 p21、Myc、14-3-3 zeta、细胞周期蛋白 A、细胞周期蛋白 B1 和 GADD153 在 MCF+FIR 和 MCF+SOD 细胞中组成型过表达（2 至 10 倍）的基因。在 Sod2 敲除小鼠 (-/-) 的成纤维细胞以及表达反义 MnSOD 的 MCF+FIR 和 MCF+SOD 细胞中，辐射诱导的这 6 个基因的表达受到抑制。通过使用突变型 IkappaBalpha 抑制 MCF+FIR 细胞中的 NF-kappaB 转录活性，可抑制放射抗性并降低 MnSOD、14-3-3 zeta、GADD153、细胞周期蛋白 A 和细胞周期蛋白 B1 mRNA 的稳态水平。相反，突变型 IkappaBalpha 无法抑制 MCF+SOD 细胞中的放射抗性或减少 14-3-3 zeta、GADD153、细胞周期蛋白 A 和细胞周期蛋白 B1 mRNA，其中 MnSOD 过表达与 NF-kappaB 无关。这些结果支持这样的假设：NF-kappaB 能够调节 MnSOD 的表达，而 MnSOD 反过来又能够增加参与辐射诱导适应性反应的基因的表达。
Antioxidant enzymes are critical in oxidative stress responses. Radioresistant variants isolated from MCF-7 human carcinoma cells following fractionated ionizing radiation (MCF+FIR cells) or overexpression of manganese superoxide dismutase (MCF+SOD cells) demonstrated dose-modifying factors at 10% isosurvivall of 1.8 and 2.3, respectively. MCF+FIR and MCF-7 cells (exposed to single-dose radiation) demonstrated 5- to 10-fold increases in MnSOD activity, mRNA, and immunoreactive protein. Radioresistance in MCF+FIR and MCF+SOD cells was reduced following expression of antisense MnSOD. DNA microarray analysis and immunoblotting identified p21, Myc, 14-3-3 zeta, cyclin A, cyclin B1, and GADD153 as genes constitutively overexpressed (2- to 10-fold) in both MCF+FIR and MCF+SOD cells. Radiation-induced expression of these six genes was suppressed in fibroblasts from Sod2 knockout mice (-/-) as well as in MCF+FIR and MCF+SOD cells expressing antisense MnSOD. Inhibiting NF-kappaB transcriptional activity in MCF+FIR cells, by using mutant IkappaBalpha, inhibited radioresistance as well as reducing steady-state levels of MnSOD, 14-3-3 zeta, GADD153, cyclin A, and cyclin B1 mRNA. In contrast, mutant IkappaBalpha was unable to inhibit radioresistance or reduce 14-3-3 zeta, GADD153, cyclin A, and cyclin B1 mRNAs in MCF+SOD cells, where MnSOD overexpression was independent of NF-kappaB. These results support the hypothesis that NF-kappaB is capable of regulating the expression of MnSOD, which in turn is capable of increasing the expression of genes that participate in radiation-induced adaptive responses.