Abstract
Small heterodimer partner (SHP) is an epigenetically regulated nuclear transcriptional repressor that suppresses the development of liver cancer by inhibiting cellular growth. Here we report a novel cytoplasmic function of SHP through its regulation of mitochondrial activity. SHP is a pivotal cell death receptor that targets mitochondria, where it binds with Bcl-2, disrupts Bcl-2/Bid interaction, and induces cytochrome c release. The apoptosis inducer AHPN {retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid} acts by regulating SHP gene expression and promotes the translocation of SHP from the nucleus to the mitochondria. Induction of apoptosis by SHP activation inhibits peritoneal pancreatic tumor growth. Our findings provide for the first time a mechanism by which SHP regulates cell survival, namely, by controlling mitochondrial function via modulating the activity of Bcl-2 through AHPN-mediated or AHPN-independent action. Thus, SHP regulates a mechanism by which apoptotic signals can mediate local control of mitochondrial function and apoptosis, which in turn may limit tumorigenesis.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adamantane / analogs & derivatives
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Adamantane / pharmacology
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Animals
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Apoptosis* / drug effects
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Cell Nucleus / drug effects
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Cell Nucleus / metabolism
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Cell Proliferation / drug effects
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Cell Respiration / drug effects
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Cinnamates / pharmacology
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Cytochromes c / metabolism
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Fibroblasts / drug effects
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Fibroblasts / metabolism
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Fibroblasts / pathology
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Gene Deletion
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Gene Expression Regulation / drug effects
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Hepatocyte Nuclear Factor 4 / metabolism
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Hepatocytes / drug effects
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Hepatocytes / metabolism
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Hepatocytes / pathology
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Mice
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Mitochondria / drug effects
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Mitochondria / metabolism*
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Pancreatic Neoplasms / metabolism
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Pancreatic Neoplasms / pathology*
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Protein Binding / drug effects
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Protein Stability / drug effects
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Protein Transport / drug effects
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Reactive Oxygen Species / metabolism
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Receptors, Cytoplasmic and Nuclear / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Receptors, Death Domain / genetics
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Receptors, Death Domain / metabolism*
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Retinoids / pharmacology
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Signal Transduction / drug effects
Substances
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4-(3-(1-adamantyl)-4-hydroxyphenyl)-3-chlorocinnamic acid
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CD 437
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Cinnamates
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Hepatocyte Nuclear Factor 4
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Hnf4a protein, mouse
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Nr5a2 protein, mouse
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Proto-Oncogene Proteins c-bcl-2
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Reactive Oxygen Species
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Receptors, Cytoplasmic and Nuclear
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Receptors, Death Domain
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Retinoids
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nuclear receptor subfamily 0, group B, member 2
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Cytochromes c
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Adamantane