Characterization of insulin-like growth factor I (IGF-I) receptors of human breast cancer cells

Biochem Biophys Res Commun. 1988 Jul 15;154(1):326-31. doi: 10.1016/0006-291x(88)90688-2.

Abstract

Studies of binding of IGF-I to a plasma-membrane-enriched subcellular fraction prepared from MCF-7 human breast cancer cells reveal the presence of 0.2 pmols specific binding sites for this mitogen per mg membrane protein, with an equilibrium affinity constant of 1.45 nM-1. Competition studies with insulin, IGF-II, and an anti-IGF-I receptor antibody are consistent with the presence of specific IGF-I receptors, and SDS-PAGE showed binding to a 130 kDa subunit identical to that of receptors from human placenta. In addition, we show that IGF-I is more potent than estradiol and comparable to EGF in stimulating in vitro proliferation of MCF-7 cells, and that IGF-I-stimulated proliferation of these cells is inhibited by a blocking monoclonal antibody against the IGF-I receptor. These results demonstrate that IGF-I is an important mitogen for MCF-7 cells and that the mitogenic effect is mediated by specific IGF-I receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Cell Division / drug effects
  • Cell Line
  • Cell Membrane / metabolism
  • DNA Replication
  • Epidermal Growth Factor / pharmacology
  • Humans
  • Insulin-Like Growth Factor I / metabolism*
  • Insulin-Like Growth Factor I / pharmacology
  • Kinetics
  • Mitogens
  • Receptor, Insulin / isolation & purification
  • Receptor, Insulin / metabolism*
  • Receptors, Somatomedin
  • Somatomedins / metabolism*

Substances

  • Mitogens
  • Receptors, Somatomedin
  • Somatomedins
  • Epidermal Growth Factor
  • Insulin-Like Growth Factor I
  • Receptor, Insulin