Mitochondria-Targeted Superoxide Dismutase (SOD2) Regulates Radiation Resistance and Radiation Stress Response in HeLa Cells
Mitochondria-Targeted Superoxide Dismutase (SOD2) Regulates Radiation Resistance and Radiation Stress Response in HeLa Cells
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DOI：
10.1269/jrr.11034
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发表时间：
2012-01-01
影响因子：
2
通讯作者：
Zhang-Akiyama, Qiu-Mei
中科院分区：
文献类型：
--
作者：
Hosoki, Ayaka;Yonekura, Shin-Ichiro;Zhang-Akiyama, Qiu-Mei
活性氧（ROS）充当电离辐射引起的细胞损伤的介质。先前的研究表明，MnSOD (SOD2) 在哺乳动物细胞免受电离辐射的保护中发挥着关键作用。在本研究中，我们构建了两种过表达 SOD2 的稳定 HeLa 细胞系：He La S3/SOD2 和 T-REx HeLa/SOD2，以阐明 SOD2 防辐射的机制。线粒体中 SOD2 的过度表达增强了 He La S3 和 T-REx He La 细胞在伽马射线照射后的存活率。与对照细胞相比，He La S3/SOD2 和 T-REx HeLa/SOD2 细胞中 γ H2AX 的水平显着降低。 MitoSox (TM) Red 测定表明，两种表达 SOD2 的细胞系均显示出对线粒体中超氧化物生成的抑制。此外，使用荧光探针（2',7'-二氯荧光素）的流式细胞术显示，在照射后孵育期间，He La S3细胞中ROS的细胞水平增加，但在He La S3/SOD2细胞中这种增加明显减弱。 DNA 微阵列分析显示，在分析的 47,000 个探针组中，对照细胞和 HeLa S3/SOD2 细胞中，117 个和 166 个探针在 5.5 Gy 伽马射线照射后分别显示出超过 2 倍的变化。通路分析揭示了受辐射的对照细胞和受辐射的 SOD2 过表达细胞中不同的表达谱。这些结果表明，SOD2 通过抑制线粒体中产生的 ROS 引起的受辐射细胞氧化应激以及调节在电离辐射防护中发挥关键作用的基因表达来保护 HeLa 细胞免受伽马射线的细胞影响。
Reactive oxygen species (ROS) act as a mediator of ionizing radiation-induced cellular damage. Previous studies have indicated that MnSOD (SOD2) plays a critical role in protection against ionizing radiation in mammalian cells. In this study, we constructed two types of stable He La cell lines overexpressing SOD2, He La S3/SOD2 and T-REx HeLa/SOD2, to elucidate the mechanisms underlying the protection against radiation by SOD2. SOD2 overexpression in mitochondria enhanced the survival of He La S3 and T-REx He La cells following gamma-irradiation. The levels of gamma H2AX significantly decreased in He La S3/SOD2 and T-REx HeLa/SOD2 cells compared with those in the control cells. MitoSox (TM) Red assays showed that both lines of SOD2-expressing cells showed suppression of the superoxide generation in mitochondria. Furthermore, flow cytometry with a fluorescent probe (2',7'-dichlorofluorescein) revealed that the cellular levels of ROS increased in He La S3 cells during post-irradiation incubation, but the increase was markedly attenuated in He La S3/SOD2 cells. DNA microarray analysis revealed that, of 47,000 probe sets analyzed, 117 and 166 probes showed more than 2-fold changes after 5.5 Gy of gamma-irradiation in control and HeLa S3/SOD2 cells, respectively. Pathway analysis revealed different expression profiles in irradiated control cells and irradiated SOD2-overexpressing cells. These results indicate that SOD2 protects HeLa cells against cellular effects of gamma-rays through suppressing oxidative stress in irradiated cells caused by ROS generated in the mitochondria and through regulating the expression of genes which play a critical role in protection against ionizing radiation.