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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2006-6-16
pubmed:abstractText
IGF-binding protein (IGFBP)-3 is generally considered to have actions that counterbalance those of IGFs and is therefore being developed as a cancer treatment. In breast tumors, however, high levels are associated with aggressive tumors and poor prognosis. Consistent with this we have demonstrated that although IGFBP-3 and a non-IGF-binding fragment (serine phosphorylation domain peptide) reduced attachment and enhanced apoptosis of Hs578T breast cancer cells cultured on collagen or laminin, it promoted their attachment and survival on fibronectin, which is abundant in the matrix of aggressive tumors. We have now examined the factors that determine whether IGFBP-3 has positive or negative actions on breast epithelial cells. IGFBP-3 also promoted survival of Hs578T cells in the presence of an antibody to the beta1-integrin subunit or when cholesterol-stabilized complexes were disrupted. These actions were blocked by IGF-I or a MAPK inhibitor. Serine phosphorylation domain peptide had similar actions on MCF-7 cells that were again reversed on fibronectin or with disruption of cholesterol-stabilized complexes and blocked by the beta1-integrin antibody. In contrast, IGFBP-3 promoted growth and survival for nonmalignant MCF-10A cells, but these effects were again reversed on fibronectin and blocked by the beta1 antibody or a MAPK inhibitor or by disruption of cholesterol-stabilized complexes. On Hs578T cells, IGFBP-3 bound to caveolin-1 and beta1-integrins, enhancing their aggregation, the recruitment of focal adhesion kinase, and the activation of MAPK. In summary, with three breast epithelial cell lines, IGFBP-3 had positive or negative effects on growth and survival dependent upon the status of cholesterol-stabilized integrin receptor complexes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
147
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3484-500
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Insulin-like growth factor binding protein 3 has opposing actions on malignant and nonmalignant breast epithelial cells that are each reversible and dependent upon cholesterol-stabilized integrin receptor complexes.
pubmed:affiliation
Department of Clinical Sciences at North Bristol, IGFs and Metabolic Endocrinology Group, University of Bristol, The Medical School, Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB, United Kingdom.
pubmed:publicationType
Journal Article