Linked Life Data

1649393

Source:http://linkedlifedata.com/resource/pubmed/id/1649393

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1991-8-16
pubmed:abstractText
Insulin-like growth factor-I (IGF-I) receptors are present in breast cancer cells and may play a role in breast cancer cell growth. We have studied the effect of progestins on IGF-I receptors in T47D human breast cancer cells. T47D cells constitutively express high levels of progesterone receptors and are a model for studying the regulation of cellular functions by progestins. Treatment of T47D cells with either progesterone or the synthetic progestin promegestone (R5020) decreased IGF-I receptor content by approximately 50%, as measured by Scatchard analysis and receptor biosynthesis studies. In contrast to progestins, estradiol, dexamethasone, and dihydrotestosterone did not influence IGF-I receptor content. No effect of R5020 was seen after 12 h of incubation, a near-maximal effect was seen after 24 h, and greatest effects were seen after 72 h. R5020 decreased IGF-I receptor mRNA abundance, indicating that progestins acted at the level of gene expression. However, progestins also increased the secretion of IGF-II, a ligand for the IGF-I receptor. In contrast to IGF-II, T47D cells did not express IGF-I. The addition of exogenous IGF-II to T47D cells down-regulated both IGF-I receptor binding and IGF-I receptor mRNA abundance. This study indicates, therefore, that progestins regulate IGF-I receptors in breast cancer cells and suggests that this regulation occurs via an autocrine pathway involving enhanced IGF-II secretion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
5
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
709-17
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Progestins induce down-regulation of insulin-like growth factor-I (IGF-I) receptors in human breast cancer cells: potential autocrine role of IGF-II.
pubmed:affiliation
Division of Diabetes and Endocrine Research, Mount Zion Medical Center, San Francisco, California.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't