Document Detail


Autophagic degradation of active caspase-8: a crosstalk mechanism between autophagy and apoptosis.
MedLine Citation:
PMID:  20724831     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Apoptotic defects endow tumor cells with survival advantages. Such defects allow the cellular stress response to take the path of cytoprotective autophagy, which either precedes or effectively blocks an apoptotic cascade. Inhibition of the cytoprotective autophagic response shifts the cells toward apoptosis, by interfering with an underlying molecular mechanism of cytoprotection. The current study has identified such a mechanism that is centered on the regulation of caspase-8 activity. The study took advantage of Bax(-/-) Hct116 cells that are TRAIL-resistant despite significant DISC processing of caspase-8, and of the availability of a caspase-8-specific antibody that exclusively detects the caspase-8 large subunit or its processed precursor. Utilizing these biological tools, we investigated the expression pattern and subcellular localization of active caspase-8 in TRAIL-mediated autophagy and in the autophagy-to-apoptosis shift upon autophagy inhibition. Our results suggest that the TRAIL-mediated autophagic response counter-balances the TRAIL-mediated apoptotic response by the continuous sequestration of the large caspase-8 subunit in autophagosomes and its subsequent elimination in lysosomes. The current findings are the first to provide evidence for regulation of caspase activity by autophagy and thus broaden the molecular basis for the observed polarization between autophagy and apoptosis.
Authors:
Wen Hou; Jie Han; Caisheng Lu; Leslie A Goldstein; Hannah Rabinowich
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-10-16
Journal Detail:
Title:  Autophagy     Volume:  6     ISSN:  1554-8635     ISO Abbreviation:  Autophagy     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-24     Completed Date:  2011-03-01     Revised Date:  2012-05-07    
Medline Journal Info:
Nlm Unique ID:  101265188     Medline TA:  Autophagy     Country:  United States    
Other Details:
Languages:  eng     Pagination:  891-900     Citation Subset:  IM    
Affiliation:
Department of Pathology, The University of Pittsburgh School of Medicine, and The University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA.
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MeSH Terms
Descriptor/Qualifier:
Antineoplastic Agents / pharmacology
Apoptosis / physiology*
Apoptosis Regulatory Proteins / genetics,  metabolism
Autophagy / physiology*
Caspase 8 / metabolism*
Cell Line, Tumor
Cisplatin / pharmacology
Gene Knockdown Techniques
Humans
Membrane Proteins / genetics,  metabolism
Microtubule-Associated Proteins / genetics,  metabolism
Pepstatins / metabolism
Protease Inhibitors / metabolism
TNF-Related Apoptosis-Inducing Ligand / metabolism
bcl-2-Associated X Protein / genetics,  metabolism
Grant Support
ID/Acronym/Agency:
R01 CA111786/CA/NCI NIH HHS; R01 CA134776/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Antineoplastic Agents; 0/Apoptosis Regulatory Proteins; 0/BECN1 protein, human; 0/Membrane Proteins; 0/Microtubule-Associated Proteins; 0/Pepstatins; 0/Protease Inhibitors; 0/TNF-Related Apoptosis-Inducing Ligand; 0/bcl-2-Associated X Protein; 0/light chain 3, human; 15663-27-1/Cisplatin; 39324-30-6/pepstatin; EC 3.4.22.-/Caspase 8
Comments/Corrections

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