Linked Life Data

7750475

Source:http://linkedlifedata.com/resource/pubmed/id/7750475

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1995-6-19
pubmed:abstractText
Insulin-like growth factor I (IGF-I) receptors and membrane-associated IGF-binding proteins (IGFBPs) were examined in Ishikawa endometrial cancer cells. Our findings suggest that about 95% of [125I]IGF-I is bound to membrane-associated IGFBPs rather than to IGF-I receptors. Specifically, [125I]IGF-I binding to cell membranes could be completely displaced by cold IGF-I or IGF-II, but not by insulin, suggesting that binding was primarily due to IGFBPs. This was confirmed by using [125I]des-(1-3)IGF-I as the ligand. Des-(1-3) IGF-I binds with high affinity to IGF-I receptors, but with markedly lower affinity to IGFBPs. [125I]Des-(1-3)IGF-I bound to Ishikawa cells was displaced by IGF-I, IGF-II, and insulin. These results suggest that measuring IGF-I receptor levels using labeled IGF-I may be misleading. Accordingly, we evaluated the differential binding of [125I]IGF-I and [125I]des-(1-3)IGF-I to study the involvement of the IGF system in the stimulation of Ishikawa cell growth by estradiol. IGF-I stimulates Ishikawa cell proliferation, but at low concentrations, and this stimulation is largely dependent on the presence of estradiol. Estradiol caused a 2.5-fold increase in IGF-I receptor levels. Moreover, estradiol reduced soluble IGFBP levels, presumably increasing the availability of IGFs for their receptors. This elevation in IGF-I receptor levels and the decrease in IGFBP levels were accompanied by a 3.5-fold increase in IGF-I receptor messenger RNA and a 2.5-fold decrease in IGFBP messenger RNAs. These experiments suggest that estradiol sensitizes endometrial cancer cells to the effects of IGFs by simultaneously elevating receptor levels and decreasing (potentially inhibitory) IGFBP levels.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
136
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2531-7
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Modulation of insulin-like growth factor I (IGF-I) receptors and membrane-associated IGF-binding proteins in endometrial cancer cells by estradiol.
pubmed:affiliation
Clinical Biochemistry Department, Faculty of Health Sciences, Ben-Gurion University of the Negev, Soroka Medical Center of Kupat Holim, Beer-Sheva, Israel.
pubmed:publicationType
Journal Article