Linked Life Data

15833037

Source:http://linkedlifedata.com/resource/pubmed/id/15833037

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2005-4-18
pubmed:abstractText
Although benzene induces leukemias in humans, the compound is not believed to generate chromosomal damage directly. Rather, benzene is thought to act through a series of phenolic- and quinone-based metabolites, especially 1,4-benzoquinone. A recent study found that 1,4-benzoquinone is a potent topoisomerase II poison in vitro and in cultured human cells [Lindsey et al. (2004) Biochemistry 43, 7363-7374]. Because benzene is metabolized to multiple compounds in addition to 1,4-benzoquinone, we determined the effects of several phenolic metabolites, including catechol, 1,2,4-benzenetriol, 1,4-hydroquinone, 2,2'-biphenol, and 4,4'-biphenol, on the DNA cleavage activity of human topoisomerase II alpha. Only 1,4-hydroquinone generated substantial levels of topoisomerase II-mediated DNA scission. DNA cleavage with this compound approached levels observed with 1,4-benzoquinone (approximately 5- vs 8-fold) but required a considerably higher concentration (approximately 250 vs 25 microM). 1,4-Hydroquinone is a precursor to 1,4-benzoquinone in the body and can be activated to the quinone by redox cycling. It is not known whether the effects of 1,4-hydroquinone on human topoisomerase II alpha reflect a lower reactivity of the hydroquinone or a low level of activation to the quinone. The high concentration of 1,4-hydroquinone required to increase enzyme-mediated DNA cleavage is consistent with either explanation. 1,4-Hydroquinone displayed attributes against topoisomerase II alpha, including DNA cleavage specificity, that were similar to those of 1,4-benzoquinone. However, 1,4-hydroquinone consistently inhibited DNA ligation to a greater extent than 1,4-benzoquinone. This latter result implies that the hydroquinone may display (at least in part) independent activity against topoisomerase II alpha. The present findings are consistent with the hypothesis that topoisomerase II alpha plays a role in the initiation of specific types of leukemia that are induced by benzene and its metabolites.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0893-228X
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
761-70
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Effects of benzene metabolites on DNA cleavage mediated by human topoisomerase II alpha: 1,4-hydroquinone is a topoisomerase II poison.
pubmed:affiliation
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural