Abstract
Death induced by doxorubicin (dox) in neuroblastoma (NB) cells was originally thought to occur via the Fas pathway, however since studies suggest that caspase-8 expression is silenced in most high stage NB tumors, it is more probable that dox-induced death occurs via a different mechanism. Caspase-8 silenced N-type invasive NB cell lines LAN-1 and IMR-32 were investigated for their sensitivity to dox, and compared to S-type noninvasive SH-EP NB cells expressing caspase-8. All cell lines had similar sensitivities to dox, independently of caspase-8 expression. Dox induced caspase-3, -7, -8 and -9 and Bid cleavage in S-type cells and death was blocked by caspase inhibitors but not by oxygen radical scavenger BHA. In contrast, dox-induced death in N-type cells was caspase-independent and was inhibited by BHA. Dox induced a drop in mitochondrial membrane permeability in all cell lines. Dox-induced death in S-type cells gave rise to apoptotic nuclei, whereas in N-type cells nuclei were non-apoptotic in morphology. Transfection of SH-EP cells with a dominant negative FADD mutant inhibited TRAIL-induced death, but had no effect on dox-induced apoptosis. These results suggest that S-type cells undergo apoptosis after dox treatment independently of death receptors, whereas N-type cells are killed by a caspase-independent mechanism.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Antineoplastic Agents / pharmacology*
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Antioxidants / pharmacology
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Apoptosis / drug effects*
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Apoptosis / physiology
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Apoptosis Regulatory Proteins
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Butylated Hydroxyanisole / pharmacology
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Carrier Proteins / genetics
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Carrier Proteins / immunology
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Carrier Proteins / metabolism*
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Caspase Inhibitors
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Caspases / metabolism*
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Cell Nucleus / metabolism
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Cell Survival / drug effects
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Cell Survival / physiology
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Cells, Cultured
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Doxorubicin / pharmacology*
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Drug Resistance, Neoplasm / physiology
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Enzyme Inhibitors / pharmacology
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Fas-Associated Death Domain Protein
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Genes, Dominant
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Humans
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Membrane Glycoproteins / pharmacology
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Neoplasm Invasiveness / physiopathology
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Neuroblastoma / drug therapy*
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Neuroblastoma / metabolism*
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Neuroblastoma / pathology
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Reactive Oxygen Species
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TNF-Related Apoptosis-Inducing Ligand
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Transfection
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Tumor Necrosis Factor-alpha / pharmacology
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Antineoplastic Agents
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Antioxidants
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Apoptosis Regulatory Proteins
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Carrier Proteins
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Caspase Inhibitors
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Enzyme Inhibitors
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FADD protein, human
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Fas-Associated Death Domain Protein
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Membrane Glycoproteins
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Reactive Oxygen Species
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TNF-Related Apoptosis-Inducing Ligand
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TNFSF10 protein, human
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Tumor Necrosis Factor-alpha
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Tumor Suppressor Protein p53
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Butylated Hydroxyanisole
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Doxorubicin
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Caspases