Insuun-like growth factor binding proteins in human breast cancer cells: Relationship to hIGFBP-2 and hIGFBP-3

Daisy D. De Leon, Bert Barker, Darrell M. Wilson, George Lamson, Ron G. Rosenfeld

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

Human breast cancer cells (HBCC) secrete at least four different forms of IGFBPs. We have previously demonstrated that hIGFBP-1 is a minor component of IGFBPs secreted by Hs578T cells and is absent in CM from MCF-7 cells. In our present report, we describe the immunological and structural relationship of HBCC IGFBPs to hIGFBP-2 and hIGFBP-3. Analysis of conditioned media (CM) from Hs578T by Western ligand blotting revealed three IGFBPs of apparent Mr = 38K, 28K and 24K; CM from MCF-7 revealed only two IGFBPs, of apparent Mr=31K and 24K. Immunoprecipitation studies with polyclonal antibodies raised against hIGFBP-2 and hIGFBP-3 demonstrated that the 38KIGFBP in Hs578T CM is immunologically related to hIGFBP-3, while the 31K IGFBP in MCF-7 cells is related to the hIGFBP-2. Analysis by Northern blot demonstrated that MCF-7 cells contained mRNA for hIGFBP-2, while Hs578T cells contained the mRNA characteristic of the hIGFBP-3. The identity of the 24K IGFBP remains unknown, and may represent a distinct IGFBP. Of note, assay of CM following removal of BPs by acid chromatography demonstrated no detectable IGF-I or -II. The role of these IGFBPs in HBCC is of interest in view of the potential modulation of IGF actions by these proteins.

Original languageEnglish (US)
Pages (from-to)530-532
Number of pages3
JournalJournal of Clinical Endocrinology and Metabolism
Volume71
Issue number2
DOIs
StatePublished - Aug 1990

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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