Linked Life Data

9454737

Source:http://linkedlifedata.com/resource/pubmed/id/9454737

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1998-5-28
pubmed:abstractText
Treatment of U-937 promonocytic cells with the DNA topoisomerase II inhibitor etoposide rapidly caused death by apoptosis, as determined by changes in chromatin structure, production of DNA breaks, nucleosome-sized DNA degradation, decrease in mitochondrial membrane potential and phosphatidyl serine translocation in the plasma membrane, and at the same time induced intracellular acidification. Both the execution of the apoptotic process and the intracellular acidification were reduced by the addition of forskolin plus theophylline or other cAMP increasing agents. These agents also attenuated the induction of apoptosis by camptothecin, heat-shock, cadmium chloride and X-radiation. Although etoposide slightly increased the production of reactive oxygen intermediates, this increase was not prevented by forskolin plus theophylline, and the addition of antioxidant agents failed to inhibit apoptosis. Etoposide caused a great increase in NF-(kappa)B binding activity, which was not prevented by forskolin plus theophylline, while AP-1 binding was little affected by the topoisomerase inhibitor. The treatments did not significantly alter the levels of Bcl-2 and Bax. By contrast, the expression of c-myc, which was very high in untreated U-937 cells and only partially inhibited by etoposide, was rapidly and almost totally abolished by the cAMP increasing agents. Finally, it was observed that etoposide caused a transient dephosphorylation of retinoblastoma (Rb), which was associated with cleavage of poly(ADP-ribose) polymerase (PARP). Both Rb dephosphorylation and PARP cleavage were inhibited by forskolin plus theophylline. The inhibition of Rb (type I) phosphatase and ICE/CED-3-like protease activities, and the abrogation of c-myc expression, are mechanisms which could explain the anti-apoptotic action of cAMP increasing agents in myeloid cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9533
pubmed:author
pubmed:issnType
Print
pubmed:volume
111 ( Pt 5)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
637-44
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
cAMP increasing agents attenuate the generation of apoptosis by etoposide in promonocytic leukemia cells.
pubmed:affiliation
Centro de Investigaciones Bioógicas, CSIC, Velázquez 144, 28006-Madrid, Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't