de Souza Luiz Felipe, Schmitz Ariana Ern, da Silva Luana Caroline Schüler, de Oliveira Karen Andrinéia, Nedel Cláudia Beatriz, Tasca Carla Inês, de Bem Andreza Fabro, Farina Marcelo, Dafre Alcir Luiz
Department of Biochemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Brazil.
Department of Biochemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Brazil.
Toxicol In Vitro. 2017 Aug;42:273-280. doi: 10.1016/j.tiv.2017.04.028. Epub 2017 Apr 29.
Thiol homeostasis has a critical role in the maintenance of proper cellular functions and survival, being coordinated by the action of several reductive enzymes, including glutathione (GSH)/glutathione reductase (GR) and thioredoxin (Trx)/thioredoxin reductase (TrxR) systems. Here, we investigated the effects of the GR inhibitor 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylthiocarbonylamino)phenylthiocarbamoylsulfanyl]propionic acid (2-AAPA) on the activity of thiol reductases (GR and TrxR), redox balance and mitochondrial function of A172 glioblastoma cells. 2-AAPA inhibited cell GR (IC=6.7μM) and TrxR (IC=8.7μM). A significant decrease in the cellular ability to decompose cumene hydroperoxide was observed and associated to a greater susceptibility to this peroxide. The redox state of peroxiredoxins (Prx1, Prx2 and Prx3) was markedly shifted to dimer 30min after treatment with 100μM 2-AAPA, an event preceding 2-AAPA-induced decrease in cell viability. Furthermore, mitochondrial function was also severely impaired, leading to a decrease in the respiratory control ratio, reserve capacity, and ATP synthesis-coupled respiration, as well as an increase in mitochondrial membrane potential. Our results indicate that inhibition of GR and TrxR activities, disruption of the ability to detoxify peroxides, increased oxidation of Prxs, as well as compromised mitochondrial function represent early events mediating 2-AAPA toxicity to A172 glioblastoma cells.
硫醇稳态在维持细胞正常功能和生存中起着关键作用，它由几种还原酶的作用协调，包括谷胱甘肽（GSH）/谷胱甘肽还原酶（GR）和硫氧还蛋白（Trx）/硫氧还蛋白还原酶（TrxR）系统。在此，我们研究了GR抑制剂2-乙酰氨基-3-[4-(2-乙酰氨基-2-羧乙基硫基硫代羰基氨基)苯基硫代氨基甲酰硫基]丙酸（2-AAPA）对A172胶质母细胞瘤细胞硫醇还原酶（GR和TrxR）活性、氧化还原平衡及线粒体功能的影响。2-AAPA抑制细胞GR（IC = 6.7μM）和TrxR（IC = 8.7μM）。观察到细胞分解氢过氧化异丙苯的能力显著下降，并与对该过氧化物的更高敏感性相关。在用100μM 2-AAPA处理30分钟后，过氧化物酶（Prx1、Prx2和Prx3）的氧化还原状态明显转变为二聚体，这一事件先于2-AAPA诱导的细胞活力下降。此外，线粒体功能也严重受损，导致呼吸控制率、储备容量和ATP合成偶联呼吸下降，以及线粒体膜电位升高。我们的结果表明，抑制GR和TrxR活性、破坏过氧化物解毒能力、增加Prxs的氧化以及线粒体功能受损是介导2-AAPA对A172胶质母细胞瘤细胞毒性的早期事件。
