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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
38
pubmed:dateCreated
2003-9-15
pubmed:abstractText
A number of clinically useful anticancer drugs, including etoposide (VP-16), target DNA topoisomerase (topo) II. These drugs, referred to as topo II poisons, stabilize cleavable complexes, thereby generating DNA double-strand breaks. Bis-2,6-dioxopiperazines such as ICRF-193 also inhibit topo II by inducing a distinct type of DNA damage, termed topo II clamps, which has been believed to be devoid of double-strand breaks. Despite the biological and clinical importance, the molecular mechanisms for the repair of topo II-mediated DNA damage remain largely unknown. Here, we perform genetic analyses using the chicken DT40 cell line to investigate how DNA lesions caused by topo II inhibitors are repaired. Notably, we show that LIG4-/- and KU70-/- cells, which are defective in nonhomologous DNA end-joining (NHEJ), are extremely sensitive to both VP-16 and ICRF-193. In contrast, RAD54-/- cells (defective in homologous recombination) are much less hypersensitive to VP-16 than the NHEJ mutants and, more importantly, are not hypersensitive to ICRF-193. Our results provide the first evidence that NHEJ is the predominant pathway for the repair of topo II-mediated DNA damage; that is, cleavable complexes and topo II clamps. The outstandingly increased cytotoxicity of topo II inhibitors in the absence of NHEJ suggests that simultaneous inhibition of topo II and NHEJ would provide a powerful protocol in cancer chemotherapy involving topo II inhibitors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
35897-902
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:12842886-Animals, pubmed-meshheading:12842886-Antineoplastic Agents, pubmed-meshheading:12842886-Antineoplastic Agents, Phytogenic, pubmed-meshheading:12842886-Cell Line, pubmed-meshheading:12842886-Chickens, pubmed-meshheading:12842886-DNA Damage, pubmed-meshheading:12842886-DNA Repair, pubmed-meshheading:12842886-DNA Topoisomerases, Type II, pubmed-meshheading:12842886-Dose-Response Relationship, Drug, pubmed-meshheading:12842886-Drug Resistance, Neoplasm, pubmed-meshheading:12842886-Etoposide, pubmed-meshheading:12842886-Genetic Vectors, pubmed-meshheading:12842886-Heterozygote, pubmed-meshheading:12842886-Models, Biological, pubmed-meshheading:12842886-Models, Genetic, pubmed-meshheading:12842886-Mutation, pubmed-meshheading:12842886-Piperazines, pubmed-meshheading:12842886-Recombination, Genetic, pubmed-meshheading:12842886-Transfection, pubmed-meshheading:12842886-Transgenes
pubmed:year
2003
pubmed:articleTitle
Hypersensitivity of nonhomologous DNA end-joining mutants to VP-16 and ICRF-193: implications for the repair of topoisomerase II-mediated DNA damage.
pubmed:affiliation
Kihara Institute for Biological Research, Graduate School of Integrated Science, Yokohama City University, Totsuka-ku, Yokohama 244-0813, Japan. nadachi@yokohama-cu.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't