Abstract
Selenium is an essential micronutrient that is currently being tested for prostate cancer chemoprevention. In spite of its significant promise as a chemopreventive agent, the molecular mechanisms of selenium-mediated effects remain to be elucidated. Recent evidence suggests that selenium may mediate its chemopreventive effects by inducing apoptosis in human prostate cancer cells. Here we report that selenium-mediated apoptosis appears to involve membrane death receptor, DR5-dependent pathway in human prostate cancer cells. Selenium specifically upregulated DR5 expression but not that of DR4. Selenium upregulation of DR5 was coupled with caspase 8 activation and Bid cleavage thereby suggesting the existence of a potential cross-talk between the DR5 and the mitochondrial pathways. Thus, our results suggest that DR5 is specifically regulated by selenium and its activation may play an important role in selenium-mediated chemoprevention.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Antioxidants / pharmacology*
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Apoptosis / drug effects*
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Arabidopsis Proteins*
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BH3 Interacting Domain Death Agonist Protein
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Blotting, Western
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Carrier Proteins / metabolism
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Caspase 8
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Caspase 9
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Caspases / metabolism
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Enzyme Activation
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Fatty Acid Desaturases / genetics
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Fatty Acid Desaturases / metabolism
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Gene Expression Regulation, Neoplastic*
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Genes, Dominant
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Humans
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Male
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Mitochondria / metabolism
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Prostatic Neoplasms / metabolism
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Prostatic Neoplasms / pathology*
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Receptors, TNF-Related Apoptosis-Inducing Ligand
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Receptors, Tumor Necrosis Factor / metabolism*
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Selenium / pharmacology*
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Tumor Cells, Cultured / drug effects
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Tumor Cells, Cultured / metabolism
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Up-Regulation
Substances
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Antioxidants
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Arabidopsis Proteins
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BH3 Interacting Domain Death Agonist Protein
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BID protein, human
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Carrier Proteins
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Receptors, TNF-Related Apoptosis-Inducing Ligand
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Receptors, Tumor Necrosis Factor
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TNFRSF10A protein, human
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TNFRSF10B protein, human
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Fatty Acid Desaturases
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Fad7 protein, Arabidopsis
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CASP8 protein, human
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CASP9 protein, human
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Caspase 8
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Caspase 9
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Caspases
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Selenium