Oxidative metabolism modulates signal transduction and micronucleus formation in bystander cells from alpha-particle-irradiated normal human fibroblast cultures.
Oxidative metabolism modulates signal transduction and micronucleus formation in bystander cells from alpha-particle-irradiated normal human fibroblast cultures.
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发表时间：
2002-10
期刊：
影响因子：
11.2
通讯作者：
E. Azzam;S. M. de Toledo;D. Spitz;J. Little
中科院分区：
文献类型：
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作者：
E. Azzam;S. M. de Toledo;D. Spitz;J. Little
研究了氧化代谢在上调/激活应激诱导信号通路以及诱导旁观者细胞微核形成中的作用。通过免疫印迹和原位免疫荧光，活性Cu-Zn超氧化物歧化酶（SOD）酶和活性过氧化氢酶显示抑制p21（Waf 1）的上调，以及从正常人二倍体成纤维细胞的融合培养物中的旁观者细胞微核形成的诱导0.3-3 cGy的α-粒子照射。酶活性测定表明，外源SOD成为显着相关的细胞。显然来自含黄素氧化酶[推测为NAD（P）H-氧化酶]的活性氧物质似乎是旁观者诱导的p53和p21（Waf 1）上调以及微核形成的主要贡献者，这一点可通过二苯基碘鎓抑制这些效应得到证明。在暴露于极低通量α粒子的培养物中，也观察到核因子κ B、Raf-1、细胞外信号调节激酶1/2、c-Jun NH 2-末端激酶和p38促分裂原活化蛋白激酶及其下游效应物活化蛋白1、ELK-1、p90 RSK和活化转录因子2的快速活化。这些激酶和转录因子的激活显着衰减发生在照射过氧化氢酶或超氧化物歧化酶处理的文化。总体而言，这些结果支持的假设，超氧化物和过氧化氢产生的黄素氧化酶介导的激活几个应激诱导的信号通路，以及微核形成的旁观者细胞从培养的人细胞暴露于低通量的α粒子。
The role of oxidative metabolism in the up-regulation/activation of stress-induciblesignaling pathways as well as induction of micronucleus formation in bystander cells was investigated. By immunoblotting and in situ immunofluorescence, active Cu-Zn superoxide dismutase (SOD) enzyme and active catalase enzyme were shown to inhibit the up-regulation of p21(Waf1) as well as the induction of micronucleus formation in bystander cells from confluent cultures of normal human diploid fibroblasts irradiated with 0.3-3 cGy of alpha-particles. Enzyme activity assays indicated that exogenous SOD became significantly associated with the cells. Reactive oxygen species apparently derived from a flavin-containing oxidase enzyme [presumably an NAD(P)H-oxidase] appeared to be major contributors to the bystander-induced up-regulation of p53 and p21(Waf1) as well as micronucleus formation, as evidenced by the inhibition of these effects with diphenyliodonium. Rapid activation of nuclear factor kappaB, Raf-1, extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 mitogen-activated protein kinase and their downstream effectors activator protein 1, ELK-1, p90RSK, and activating transcription factor 2 was also observed in cultures exposed to very low fluences of alpha-particles. Significant attenuation in the activation of these kinases and transcription factors occurred in irradiated cultures treated with either SOD or catalase. Overall, these results support the hypothesis that superoxide and hydrogen peroxide produced by flavin-containing oxidase enzymes mediate the activation of several stress-inducible signaling pathways as well as micronucleus formation in bystander cells from cultures of human cells exposed to low fluences of alpha-particles.