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

Nutrients

Claire M. Weekley³  Jade B. Aitken⁴  Lydia Finney²  Stefan Vogt²  Paul K. Witting¹ 

[1] The Discipline of Pathology, Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia; E-Mail:;X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA; E-Mails:;School of Chemistry and Physics, The University of Adelaide, Adelaide, SA 5005, Australia; E-Mail:;School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; E-Mail:

关键词: selenium;    cancer;    XAS;    XFM;    selenoproteins;    SDS-PAGE;   

DOI  :  10.3390/nu5051734

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.