Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2011-1-26
pubmed:abstractText
The radiosensitizing activity of celastrol, a quinone methide triterpene was examined. We found that celastrol treatment of the NCI-H460 lung cancer cell line increased radiation-induced cell killing. The increased radiosensitivity was correlated with decreased levels of Hsp90 clients, such as EGFR, ErbB2 and survivin as well as with increased p53 expression. Celastrol inhibited the ATP-binding activity of Hsp90. Furthermore, celastrol treatment dissociated an Hsp90 client protein, EGFR, and this in turn resulted in degradation of the client protein. These results were not observed with another structurally similar triterpenoid, 6?-acetonyl-22?-hydroxytingenol (TG), suggesting that a specific structural feature of the triterpenoid is required for radiosensitization. Moreover celastrol treatment increased p53 levels by phosphorylating Ser15 and Ser20 residues as well as by inhibiting its proteasomal degradation. Celastrol may be considered an effective radiosensitizer acting as an inhibitor of Hsp90 and a p53 activator. The two activities could be applicable to a broad range of cancer cells with either wild-type or mutant p53 because either activity could be effective for the enhancement of radiation cell killing. Further analysis with other triterpenoids should identify the functional moiety of the structure and additional candidates for effective radiosensitizers, which can be used in combined radiotherapy.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/BIRC5 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/EGFR protein, human, http://linkedlifedata.com/resource/pubmed/chemical/ERBB2 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/HSP90 Heat-Shock Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Inhibitor of Apoptosis Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Microtubule-Associated Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Radiation-Sensitizing Agents, http://linkedlifedata.com/resource/pubmed/chemical/Receptor, Epidermal Growth Factor, http://linkedlifedata.com/resource/pubmed/chemical/Receptor, erbB-2, http://linkedlifedata.com/resource/pubmed/chemical/TP53 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Triterpenes, http://linkedlifedata.com/resource/pubmed/chemical/Tumor Suppressor Protein p53, http://linkedlifedata.com/resource/pubmed/chemical/tripterine
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1791-244X
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
441-6
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Enhancement of radiation sensitivity in lung cancer cells by celastrol is mediated by inhibition of Hsp90.
pubmed:affiliation
Laboratory of Modulation of Radiobiological Responses, Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul 139-706, Republic of Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't