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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2004-8-3
pubmed:abstractText
Gefitinib ("Iressa", ZD1839) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor, which blocks signal transduction pathways implicated in proliferation and survival of cancer cells. However, in vitro and in vivo studies concerning cell growth after withdrawal of gefitinib are limited. To determine whether cancer cells would resume proliferation upon removal of gefitinib, an in vitro study was undertaken using 4 human non-small cell lung cancer cell lines. With immunocytochemical staining and Western blot analysis, we confirmed positive expression of EGFR in these cell lines. We next evaluated growth inhibition before and after withdrawal of gefitinib. After incubation with 0-100 microM gefitinib for 24 h, medium containing gefitinib was removed, followed by addition of fresh growth medium to cell cultures. MTT assays were performed daily over a 6-day time course. Even at very low levels of gefitinib (<1 microM), these 4 TKB cells had 1-10% growth inhibition, respectively. With these levels of gefitinib, continued inhibitory effects after withdrawal of getitinib were observed in 3 of the 4 cell lines. Furthermore, none of the 4 cell lines, including the cell line which had abolished growth inhibition, showed accelerated re-growth rate after the withdrawal of gefitinib even in these exposure conditions. Based on our in vitro experiments, additional in vivo studies, which can compare the pre- and post-treatment growth rate, will be necessary to help better understand the mechanisms behind cell growth recovery after temporary gefitinib treatment.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1021-335X
pubmed:author
pubmed:issnType
Print
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
615-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Cell growth after withdrawal of gefitinib ("Iressa", ZD1839) in human lung cancer cells.
pubmed:affiliation
Division of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Tsukuba-city, Ibaraki 305-8575, Japan. hirosato@md.tsukuba.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't