Division of Molecular Cell Immunology and Allergology, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan.
Int J Oncol. 2013 Mar;42(3):863-72. doi: 10.3892/ijo.2013.1769. Epub 2013 Jan 10.
Intracellular reactive oxygen species (ROS) such as hydrogen peroxide (H(2)O2()) are thought to mediate apoptosis induced by death receptor ligands, including tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). However, the role of H(2)O(2) is controversial, since some evidence suggests that H(2)O(2) acts as an anti-apoptotic factor. Here, we show that exogenously applied H(2)O(2) (30-100 µM) induces cell death in TRAIL-resistant human melanoma cells via intracellular superoxide (O(2)-) generation. H(2)O(2) induced apoptotic or necrotic cell death, depending on the concentration of the oxidant applied; low concentrations of H(2)O(2) preferentially activated the caspase-dependent apoptotic pathway, while high concentrations of H(2)O(2) induced apoptotic and necrotic cell death in a caspase-independent manner. The H(2)O(2)-induced cell death was associated with increased mitochondrial membrane potential collapse and caspase-3/7 activation and ER stress responses including caspase-12 and X-box-binding protein-1 (XBP-1) activation. H(2)O(2) induced intracellular O2- generation even within the mitochondria, while TRAIL did not. The superoxide dismutase mimetic antioxidant MnTBaP [Mn (III) tetrakis (4-benzonic acid) porphyrin chloride] inhibited the H(2)O(2)-induced O(2)- generation, apoptosis and XBP-1 and caspase-12 activation at comparable concentrations. Importantly, H(2)O(2) treatment caused minimal O(2)- generation and apoptosis in normal primary melanocytes. These data show that H(2)O(2) induces endoplasmic reticulum-associated cell death via intracellular O(2)- generation and that malignant melanoma cells are more susceptible than normal cells to this oxidative cell death. The findings suggest that H(2)O(2) has therapeutic potential in the treatment of TRAIL-resistant melanoma.
细胞内活性氧（ROS），如过氧化氢（H(2)O2()），被认为介导了死亡受体配体诱导的细胞凋亡，包括肿瘤坏死因子相关凋亡诱导配体（TRAIL）。然而，H(2)O(2)的作用存在争议，因为一些证据表明 H(2)O(2) 是一种抗凋亡因子。在这里，我们表明，外源性应用的 H(2)O(2)（30-100 μM）通过细胞内超氧化物（O(2)-）的产生诱导 TRAIL 耐药的人类黑色素瘤细胞死亡。H(2)O(2)诱导的细胞死亡是凋亡性或坏死性的，取决于应用的氧化剂的浓度；低浓度的 H(2)O(2)优先激活半胱天冬酶依赖性凋亡途径，而高浓度的 H(2)O(2)以半胱天冬酶非依赖性方式诱导凋亡性和坏死性细胞死亡。H(2)O(2)诱导的细胞死亡与线粒体膜电位崩溃和半胱天冬酶-3/7 的激活以及内质网应激反应（包括半胱天冬酶-12 和 X 盒结合蛋白-1（XBP-1）的激活）有关。H(2)O(2)诱导细胞内 O2-生成，甚至在线粒体内部，而 TRAIL 则没有。超氧化物歧化酶模拟抗氧化剂 MnTBaP[Mn(III)四(4-苯甲酰酸)卟啉氯化物]在可比浓度下抑制 H(2)O(2)诱导的 O(2)-生成、凋亡和 XBP-1 和半胱天冬酶-12 的激活。重要的是，H(2)O(2)处理在正常原代黑素细胞中引起最小的 O(2)-生成和凋亡。这些数据表明，H(2)O(2)通过细胞内 O(2)-生成诱导内质网相关的细胞死亡，并且恶性黑素瘤细胞比正常细胞更容易受到这种氧化细胞死亡的影响。这些发现表明 H(2)O(2)在治疗 TRAIL 耐药性黑色素瘤方面具有治疗潜力。
