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KMID : 0603520030080010009
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Journal of Korean Association of Cancer Prevention
2003 Volume.8 No. 1 p.9 ~ p.23
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Use of Selenium to Prevent and Treat Cancer in the New Millennium
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Spallholz Julian E.
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Abstract
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Selenium has been found to have three special attributes characteristic of several of the dietary trace (metals) minerals. It is dietarily essential, being incorporated into over l3 enzymes and proteins as the 2lst universal amino acid, selenocysteine. It is pharmacologically active at supranutritional dietary levels and can prevent the development of various cancers (chemoprevention/ carcinostatic). At higher levels of dietary intake many selenium compounds, as demonstrated in animals experimentally or in natural settings, can become toxic. All three of these attributes of selenium, essentiality, carcinostatic activity and toxicity depend upon the concentration, the chemical speciation and the catalytic activity of the selenium selenide anion (selenol). Herein lays the biological magic of selenium, catalytic activity, that accounts for its essentiality in glutathione peroxidase, its pharmacology in chemoprevention and if in sufficient concentration, its toxicity. It is selenium’s redox catalytic attributes not shared to any degree by its sister element sulfur that imparts all of its biological activity. Selenium chemoprevention requires dietary supplementation with selenium beyond normal dietary intake of selenium. Supplementation continuously provides a metabolic level of catalytically active selenols. Selenols (selenides) redox cycle producing “oxidative stress”and induce apoptosis in more sensitive cancer cells. Chemoprevention likely occurs because of a differential sensitivity between cancer and normal cells to metabolically generate selenols that induce apoptosis. Differences in the effectiveness of the two leading selenoamino acid candidates for human supplementation, L-selenomethionine and L-Se-methylselenocysteine for chemoprevention will likely reside in their characteristics as substrates for enzymatic conversion to selenols and the incorporation of L-selenomethionine to body proteins. In dealing with selenium we must remember the words of Paracelsus(l393~l441), The dosage makes either a poison or a remedy.
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KEYWORD
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Selenium (Se), Selenium chemoprevention, Treatment
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