A Splice Variant of the Human Ion Channel TRPM2 Modulates Neuroblastoma Tumor Growth through Hypoxia-inducible Factor (HIF)-1/2α
A Splice Variant of the Human Ion Channel TRPM2 Modulates Neuroblastoma Tumor Growth through Hypoxia-inducible Factor (HIF)-1/2α
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DOI：
10.1074/jbc.m114.620922
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发表时间：
2014-12-26
影响因子：
4.8
通讯作者：
Miller, Barbara A.
中科院分区：
文献类型：
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作者：
Chen, Shu-jen;Hoffman, Nicholas E.;Miller, Barbara A.
钙离子通道TRPM 2在许多癌症中高度表达。在神经母细胞瘤中，全长TRPM 2（TRPM 2-L）通过增加叉头盒转录因子3a（FOXO 3a）和超氧化物歧化酶2的水平来保护细胞免受中度氧化应激。表达显性负性短亚型（TRPM 2-S）的细胞具有降低的FOXO 3a和超氧化物歧化酶2水平，降低响应于氧化应激的钙内流，并增强活性氧，导致细胞活力降低。这里，在用稳定表达TRPM 2同种型的SH-SY 5 Y神经母细胞瘤细胞产生的异种移植物中，与表达TRPM 2-L的肿瘤相比，表达TRPM 2-S的肿瘤的生长显著降低。缺氧诱导因子（HIF）-1/2 α的表达在TRPM 2-S表达肿瘤细胞中显著降低，受HIF-1/2 α调节的靶蛋白（包括参与糖酵解的靶蛋白）的表达也显著降低（乳酸脱氢酶A和烯醇化酶2）、氧化应激（FOXO 3a）、血管生成（VEGF）、线粒体自噬和线粒体功能（BNIP 3和NDUFA 4L 2）和线粒体电子传递链活性（复合物IV中的细胞色素氧化酶4.1/4.2）。HIF-1/2 α的减少是通过显著降低的HIF-1/2 α mRNA水平和TRPM 2-S表达细胞中增加的von Hippel-Lindau E3连接酶水平介导的。通过克霉唑预处理或TRPM 2-S表达抑制TRPM 2-L显著增加细胞对阿霉素的敏感性。多柔比星治疗后TRPM 2-S表达细胞的存活率降低通过获得HIF-1或-2 α功能来挽救。这些数据表明，TRPM 2活性对于肿瘤生长和多柔比星治疗后的细胞活力和存活是重要的，并且干扰TRPM 2-L功能可能是通过调节HIF-1/2 α、线粒体功能和线粒体自噬来减少肿瘤生长的新方法。
The calcium-permeable ion channel TRPM2 is highly expressed in a number of cancers. In neuroblastoma, full-length TRPM2 (TRPM2-L) protected cells from moderate oxidative stress through increased levels of forkhead box transcription factor 3a (FOXO3a) and superoxide dismutase 2. Cells expressing the dominant negative short isoform (TRPM2-S) had reduced FOXO3a and superoxide dismutase 2 levels, reduced calcium influx in response to oxidative stress, and enhanced reactive oxygen species, leading to decreased cell viability. Here, in xenografts generated with SH-SY5Y neuroblastoma cells stably expressing TRPM2 isoforms, growth of tumors expressing TRPM2-S was significantly reduced compared with tumors expressing TRPM2-L. Expression of hypoxia-inducible factor (HIF)-1/2 alpha was significantly reduced in TRPM2-S-expressing tumor cells as was expression of target proteins regulated by HIF-1/2 alpha including those involved in glycolysis (lactate dehydrogenase A and enolase 2), oxidant stress (FOXO3a), angiogenesis (VEGF), mitophagy and mitochondrial function (BNIP3 and NDUFA4L2), and mitochondrial electron transport chain activity (cytochrome oxidase 4.1/4.2 in complex IV). The reduction in HIF-1/2 alpha was mediated through both significantly reduced HIF-1/2 alpha mRNA levels and increased levels of von Hippel-Lindau E3 ligase in TRPM2-S-expressing cells. Inhibition of TRPM2-L by pretreatment with clotrimazole or expression of TRPM2-S significantly increased sensitivity of cells to doxorubicin. Reduced survival of TRPM2-S-expressing cells after doxorubicin treatment was rescued by gain of HIF-1 or -2 alpha function. These data suggest that TRPM2 activity is important for tumor growth and for cell viability and survival following doxorubicin treatment and that interference with TRPM2-L function may be a novel approach to reduce tumor growth through modulation of HIF-1/2 alpha, mitochondrial function, and mitophagy.