Identification of the insulin-like growth factor binding proteins 5 and 6 (IGFBP-5 and 6) in human breast cancer cells

Biochem Biophys Res Commun. 1992 Mar 31;183(3):1003-10. doi: 10.1016/s0006-291x(05)80290-6.

Abstract

Four estrogen receptor-positive (ER+) [MCF-7, T47D, ZR75 and BT474] and 3 ER- [Hs578T, MDA-MB-468 and MDA-MB-231] human breast cancer cell lines were examined for expression of the IGFBP-5 and IGFBP-6 genes. Northern blot analysis revealed that all cell lines, except MDA-MB-231, expressed IGFBP-5 mRNA. IGFBP-6 mRNA, however, was expressed only by the ER- cell lines. Western immunoblotting indicated that the previously unidentified 31-kDa and 32-kDa IGF binding species secreted by these cell lines are IGFBP-5. The levels of IGFBP-4 and IGFBP-5 were increased in MCF-7 cells by estradiol and IGF-I, respectively, indicating that these BPs may contribute to the growth stimulatory response to these mitogens.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Blotting, Northern
  • Blotting, Western
  • Breast Neoplasms / chemistry*
  • Carrier Proteins / analysis*
  • Female
  • Humans
  • Insulin-Like Growth Factor Binding Protein 5
  • Insulin-Like Growth Factor Binding Proteins
  • Mitogens / analysis
  • RNA, Messenger / analysis
  • Receptors, Cell Surface / analysis
  • Receptors, Somatomedin
  • Somatomedins / analysis*
  • Tumor Cells, Cultured / chemistry*

Substances

  • Carrier Proteins
  • Insulin-Like Growth Factor Binding Protein 5
  • Insulin-Like Growth Factor Binding Proteins
  • Mitogens
  • RNA, Messenger
  • Receptors, Cell Surface
  • Receptors, Somatomedin
  • Somatomedins