Zhao Chubiao, Qin Guiqi, Gao Weijie, Chen Jingqin, Liu Hongyu, Xi Gaina, Li Tan, Wu Shengnan, Chen Tongsheng
MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Life Science, South China Normal University, Guangzhou 510631, China.
MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Life Science, South China Normal University, Guangzhou 510631, China.
Cell Signal. 2014 Oct;26(10):2223-33. doi: 10.1016/j.cellsig.2014.07.001. Epub 2014 Jul 10.
Our recent studies have demonstrated the key roles of reactive oxygen species (ROS)-mediated caspase-8- and Bax-dependent apoptotic pathways in dihydroartemisinin (DHA)-induced apoptosis of A549 cells. This report is designed to investigate the proapoptotic mechanisms of DHA in gemcitabine (Gem)-resistant A549 (A549GR) cells. A549GR cells exhibited lower basal antioxidant capacity, higher level of basal ROS and intracellular Fe(2+) than Gem-sensitive A549 (A549) cells. In contrast to the sluggish ROS generation induced by Gem, DHA induced a rapid ROS generation within 30min. Moreover, Gem induced similar ROS generation in both cell lines, while DHA induced more ROS generation in A549GR cells than in A549 cells. More importantly, after treatment with DHA, A549GR cells showed more potent induction in Bax activation, loss of mitochondrial membrane potential (ΔΨm), caspase activation and apoptosis than A549 cells. Furthermore, NAC pretreatment potently prevented DHA-induced ROS generation and loss of ΔΨm as well as apoptosis, and silencing Bax by shRNA or inhibition of one of caspase-3, -8 and -9 also significantly prevented DHA-induced apoptosis in both cell lines, indicating the key roles of ROS and Bax as well as the caspases. Collectively, DHA presents more potent proapoptotic actions in A549GR cells preferentially over normal A549 cells via ROS-dependent apoptotic pathway, in which Bax and caspases are involved.
我们最近的研究已经证明了活性氧（ROS）介导的半胱天冬酶-8和Bax依赖性凋亡途径在双氢青蒿素（DHA）诱导的A549细胞凋亡中的关键作用。本报告旨在研究DHA在吉西他滨（Gem）耐药的A549（A549GR）细胞中的促凋亡机制。与Gem敏感的A549（A549）细胞相比，A549GR细胞表现出较低的基础抗氧化能力、较高水平的基础ROS和细胞内Fe(2+)。与Gem诱导的缓慢ROS生成相反，DHA在30分钟内诱导快速的ROS生成。此外，Gem在两种细胞系中诱导的ROS生成相似，而DHA在A549GR细胞中诱导的ROS生成比在A549细胞中更多。更重要的是，用DHA处理后，A549GR细胞在Bax激活、线粒体膜电位（ΔΨm）丧失、半胱天冬酶激活和凋亡方面比A549细胞表现出更强的诱导作用。此外，NAC预处理有效地阻止了DHA诱导的ROS生成、ΔΨm丧失以及凋亡，通过shRNA沉默Bax或抑制半胱天冬酶-3、-8和-9中的一种也显著阻止了DHA在两种细胞系中诱导的凋亡，表明ROS和Bax以及半胱天冬酶的关键作用。总的来说，DHA通过ROS依赖性凋亡途径在A549GR细胞中比正常A549细胞优先表现出更强的促凋亡作用，其中涉及Bax和半胱天冬酶。
