文章基本信息

标题：Ceramide-tamoxifen regimen targets bioenergetic elements in acute myelogenous leukemia
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作者：Samy A. F. Morad ; Terence E. Ryan ; P. Darrell Neufer 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2016
卷号：57
期号：7
页码：1231-1242
DOI：10.1194/jlr.M067389
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：The objective of our study was to determine the mechanism of action of the short-chain ceramide analog, C6-ceramide, and the breast cancer drug, tamoxifen, which we show coactively depress viability and induce apoptosis in human acute myelogenous leukemia cells. Exposure to the C6-ceramide-tamoxifen combination elicited decreases in mitochondrial membrane potential and complex I respiration, increases in reactive oxygen species (ROS), and release of mitochondrial proapoptotic proteins. Decreases in ATP levels, reduced glycolytic capacity, and reduced expression of inhibitors of apoptosis proteins also resulted. Cytotoxicity of the drug combination was mitigated by exposure to antioxidant. Cells metabolized C6-ceramide by glycosylation and hydrolysis, the latter leading to increases in long-chain ceramides. Tamoxifen potently blocked glycosylation of C6-ceramide and long-chain ceramides. N -desmethyltamoxifen, a poor antiestrogen and the major tamoxifen metabolite in humans, was also effective with C6-ceramide, indicating that traditional antiestrogen pathways are not involved in cellular responses. We conclude that cell death is driven by mitochondrial targeting and ROS generation and that tamoxifen enhances the ceramide effect by blocking its metabolism. As depletion of ATP and targeting the “Warburg effect” represent dynamic metabolic insult, this ceramide-containing combination may be of utility in the treatment of leukemia and other cancers.
关键词：ceramides ; sphingolipids ; leukemia ; mitochondria