Selenium Metabolism in Cancer Cells [electronic resource] : The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

• Ngôn ngữ: eng
• Ký hiệu phân loại: 630.7 Education, research, related topics
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2013
• Mô tả vật lý: Size: p. 1734-1756 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 261500
• Chủ đề: 1. 60 applied life sciences; 2. Cancer; 3. Nutrition & dietetics; 4. Sds-page; 5. Selenium; 6. Selenoproteins; 7. Xas; 8. Xfm

Tóm tắt

Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (XFM). The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed.