Linked Life Data

7564505

Source:http://linkedlifedata.com/resource/pubmed/id/7564505

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1995-11-7
pubmed:abstractText
Previously, we showed that in vitro resistance to daunorubicin (DNR) at initial diagnosis was related to a poor long-term clinical outcome in childhood acute lymphoblastic leukemia (ALL), and that cells of relapsed ALL were in vitro more resistant to DNR than cells of untreated ALL. Topoisomerase II (Topo II) is an intracellular target for anthracyclines and epipodophyllotoxins. Decreased levels and/or activity of Topo II have been associated with multidrug resistance in cell lines. We investigated Topo II alpha gene expression in fresh leukemic samples from 19 children with untreated and 14 children with relapsed ALL using a sensitive RNase protection assay. The in vitro cytotoxicity of the Topo II inhibitors DNA and teniposide (VM26) was measured using the MTT assay, and the cell cycle distribution of leukemic samples was analyzed by DNA flow cytometry. Results showed that (1) relapsed ALL samples were more resistant to DNR, but not to VM26 compared to untreated samples; (2) large interpatient variations existed in both Topo II alpha gene expression and in vitro cytotoxicity results; (3) Topo II alpha gene expression was detectable in 29/33 childhood ALL samples with a median expression of 5% the level of a relatively chemosensitive human small cell lung cancer cell line; (4) Topo II alpha gene expression did not differ between untreated and relapsed ALL; (5) Topo II alpha gene expression was positively correlated with the percentage of ALL cells in S- and G2M-phase, but not with the in vitro cytotoxicity of the drugs tested. In conclusion, resistance to DNR in childhood ALL can not be explained by decreased levels of Topo II alpha gene expression, but additional Topo II activity studies in fresh leukemia samples may need further exploration.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0887-6924
pubmed:author
pubmed:issnType
Print
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1653-60
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Topoisomerase II alpha gene expression in childhood acute lymphoblastic leukemia.
pubmed:affiliation
Department of Pediatrics, Free University Hospital, Amsterdam, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't