Linked Life Data

10962446

Source:http://linkedlifedata.com/resource/pubmed/id/10962446

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-9-26
pubmed:abstractText
Cellular resistance to etoposide has been correlated both with reduced levels and an aberrant cytoplasmic accumulation of the drug's target, topoisomerase IIalpha (topo IIalpha). It is not known, however, whether a cytoplasmic pool of topo IIalpha is sufficient to confer drug resistance on cultured mammalian cells. In our study, we have transfected mouse fibroblasts and human 293 cells with truncated forms of human topo IIalpha fused to GFP and have examined the transformants for the subcellular localization of topo IIalpha and their resistance to etoposide. Transient transfection resulted in high-level expression of all GFP-topo IIalpha fusions tested, whereas in stably transfected cells the levels varied significantly. Transfectants expressing a central or a carboxy-terminal topo IIalpha domain (aa 428-1504, 639-1028 or 1028-1504) accumulated high levels of the fusion proteins, while only very low amounts of GFP-topo IIalpha proteins were observed in cell lines expressing constructs that retain the amino-terminus of the enzyme (aa 1-1214, aa 1-939, aa 1-611). Our results suggest that the topo IIalpha amino-terminus affects the stability of truncated forms of the enzyme in mammalian cells, perhaps due to targeted degradation. Assays that screen for cell vitality and DNA synthesis reveal no significant changes in etoposide sensitivity in transfected cells expressing high levels of cytoplasmic or nuclear localized topo II fusion proteins. Retroviral expression of a cytoplasmically anchored domain of human topo IIalpha also failed to confer drug resistance. These results suggest that a cytoplasmic pool of topo IIalpha is not sufficient to render cultured mammalian cells drug resistant.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0020-7136
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
99-107
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:10962446-3T3 Cells, pubmed-meshheading:10962446-Animals, pubmed-meshheading:10962446-Antigens, Neoplasm, pubmed-meshheading:10962446-Cell Survival, pubmed-meshheading:10962446-Cells, Cultured, pubmed-meshheading:10962446-DNA Topoisomerases, Type II, pubmed-meshheading:10962446-DNA-Binding Proteins, pubmed-meshheading:10962446-Drug Resistance, pubmed-meshheading:10962446-Etoposide, pubmed-meshheading:10962446-Green Fluorescent Proteins, pubmed-meshheading:10962446-Humans, pubmed-meshheading:10962446-Isoenzymes, pubmed-meshheading:10962446-Kidney, pubmed-meshheading:10962446-Luminescent Proteins, pubmed-meshheading:10962446-Mice, pubmed-meshheading:10962446-Microscopy, Fluorescence, pubmed-meshheading:10962446-Peptide Fragments, pubmed-meshheading:10962446-Protein Structure, Tertiary, pubmed-meshheading:10962446-Rats, pubmed-meshheading:10962446-Recombinant Fusion Proteins, pubmed-meshheading:10962446-Transfection
pubmed:year
2000
pubmed:articleTitle
Ectopic expression of human topoisomerase IIalpha fragments and etoposide resistance in mammalian cells.
pubmed:affiliation
Division of Oncology, Department of Internal Medicine, University Hospital, Zürich, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't