|Title:||Resistance to hypoxia-induced necroptosis is conferred by glycolytic pyruvate scavenging of mitochondrial superoxide in colorectal cancer cells||Authors:||Huang C.-Y.
LINDA CHIA-HUI YU
|Issue Date:||2013||Journal Volume:||4||Journal Issue:||5||Start page/Pages:||e622||Source:||Cell Death and Disease||Abstract:||
Cancer cells may survive under oxygen and nutrient deprivation by metabolic reprogramming for high levels of anaerobic glycolysis, which contributes to tumor growth and drug resistance. Abnormally expressed glucose transporters (GLUTs) are colocalized with hypoxia (Hx) inducible factor (HIF)1a in peri-necrotic regions in human colorectal carcinoma. However, the underlying mechanisms of anti-necrotic resistance conferred by glucose metabolism in hypoxic cancer cells remain poorly understood. Our aim was to investigate signaling pathways of Hx-induced necroptosis and explore the role of glucose pyruvate metabolite in mechanisms of death resistance. Human colorectal carcinoma cells were Hx exposed with or without glucose, and cell necroptosis was examined by receptor-interacting protein (RIP)1/3 kinase immunoprecipitation and 32P kinase assays. Our results showed increased RIP1/3 complex formation and phosphorylation in hypoxic, but not normoxic cells in glucose-free media. Blocking RIP1 signaling, by necrostatin-1 or gene silencing, decreased lactodehydrogenase (LDH) leakage and plasma membrane disintegration. Generation of mitochondrial superoxide was noted after hypoxic challenge; its reduction by antioxidants inhibited RIP signaling and cell necrosis. Supplementation of glucose diminished the RIP-dependent LDH leakage and morphological damage in hypoxic cells, whereas non-metabolizable sugar analogs did not. Hypoxic cells given glucose showed nuclear translocation of HIF1a associated with upregulation of GLUT-1 and GLUT-4 expression, as well as increase of intracellular ATP, pyruvate and lactate levels. The glucose-mediated death resistance was ablated by iodoacetate (an inhibitor to glyceraldehyde-3-phosphate dehydrogenase), but not by UK5099 (an inhibitor to mitochondrial pyruvate carrier), suggesting that glycolytic pathway was involved in anti-necrotic mechanism. Lastly, replacing glucose with cell-permeable pyruvate derivative also led to decrease of Hx-induced necroptosis by suppression of mitochondrial superoxide in an energy-independent manner. In conclusion, glycolytic metabolism confers resistance to RIP-dependent necroptosis in hypoxic cancer cells partly through pyruvate scavenging of mitochondrial free radicals. ? 2013 Macmillan Publishers Limited. All rights reserved.
|ISSN:||2041-4889||DOI:||10.1038/cddis.2013.149||SDG/Keyword:||adenosine triphosphate; glucose; glucose transporter 1; glucose transporter 4; hypoxia inducible factor 1alpha; lactate dehydrogenase; lactic acid; mitochondrial superoxide; protein kinase; pyruvic acid; receptor interacting protein kinase 1; receptor interacting protein kinase 3; superoxide; unclassified drug; anaerobic glycolysis; article; cancer cell culture; cell damage; cell death; cell hypoxia; cell membrane; colorectal carcinoma; complex formation; controlled study; enzyme assay; enzyme phosphorylation; gene silencing; human; human cell; immunoprecipitation; intracellular signaling; necroptosis; priority journal; protein expression; upregulation; Apoptosis; Caco-2 Cells; Cell Hypoxia; Colorectal Neoplasms; Glucose; Glucose Transporter Type 1; Glucose Transporter Type 4; Glycolysis; HT29 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Imidazoles; Indoles; Mitochondria; Necrosis; Nuclear Pore Complex Proteins; Pyruvates; Receptor-Interacting Protein Serine-Threonine Kinases; RNA Interference; RNA, Small Interfering; RNA-Binding Proteins; Signal Transduction; Superoxides
|Appears in Collections:||口腔生物科學研究所|
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