Linked Life Data

18060492

Source:http://linkedlifedata.com/resource/pubmed/id/18060492

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2008-9-30
pubmed:abstractText
Although the epidermal growth factor receptor (EGFR) is frequently expressed in human primary breast carcinoma, the majority of breast cancer patients do not respond to treatment with EGFR tyrosine-kinase inhibitors such as gefitinib. We isolated through a stepwise dose escalation of the drug two gefitinib-resistant SK-Br-3 clones, ZD6 and ZD10 (ZD) cells, which showed, respectively, a three- to five-fold increase in the IC50 for gefitinib as compared with parental cells. The levels of expression of EGFR were increased in ZD cells as compared with wild-type SK-Br-3 cells. The phosphorylation of EGFR, ErbB-2, ErbB-3 and Akt was significantly reduced in gefitinib-resistant cells. In contrast, ZD cells showed levels of MAPK phosphorylation similar to untreated wild-type cells when cultured in presence of gefitinib. Persistent activation of MAPK was also observed in gefitinib-resistant clones isolated from MDA-MB-175 and MDA-MB-361 breast cancer cell lines. ZD cells showed an increased sensitivity to the MEK inhibitor PD98059 as compared with SK-Br-3 cells, and a synergistic anti-tumor effect was observed when ZD cells were treated with a combination of gefitinib and PD98059. Overexpression of a constitutively activated form of p42-MAPK in SK-Br-3 cells resulted in an approximately 50% increase in the IC50 to gefitinib. Finally, culture of ZD10 resistant cells in absence of gefitinib led to reversion of the resistant phenotype. These observations suggest that MAPK signaling might play a role in the resistance that develops in breast cancer cells after long-term exposure to gefitinib.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0167-6806
pubmed:author
pubmed:issnType
Print
pubmed:volume
112
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
25-33
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:18060492-Blotting, Western, pubmed-meshheading:18060492-Breast Neoplasms, pubmed-meshheading:18060492-Cell Adhesion, pubmed-meshheading:18060492-Cell Proliferation, pubmed-meshheading:18060492-Drug Resistance, Neoplasm, pubmed-meshheading:18060492-Enzyme Activation, pubmed-meshheading:18060492-Female, pubmed-meshheading:18060492-Humans, pubmed-meshheading:18060492-Immunoprecipitation, pubmed-meshheading:18060492-Mitogen-Activated Protein Kinase 1, pubmed-meshheading:18060492-Phosphorylation, pubmed-meshheading:18060492-Protein Kinase Inhibitors, pubmed-meshheading:18060492-Quinazolines, pubmed-meshheading:18060492-Receptor, Epidermal Growth Factor, pubmed-meshheading:18060492-Receptor, erbB-2, pubmed-meshheading:18060492-Signal Transduction, pubmed-meshheading:18060492-Tumor Cells, Cultured
pubmed:year
2008
pubmed:articleTitle
Breast cancer cells with acquired resistance to the EGFR tyrosine kinase inhibitor gefitinib show persistent activation of MAPK signaling.
pubmed:affiliation
Cell Biology and Preclinical Models Unit, INT-Fondazione Pascale, 80131, Naples, Italy. nicnorm@yahoo.com
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't