Components of the IGF system mediate the opposing effects of tamoxifen on endometrial and breast cancer cell growth

Michael Karas, Dita Kleinman, Michael Danilenko, Charles Roberts, Derek LeRoith, Joseph Levy, Yoav Sharoni

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The involvement of the IGF system in the growth regulation of hormone-dependent (e.g. endometrial and breast) cancer cells was studied. We chose two opposing effects of tamoxifen: the paradoxical stimulation of Ishikawa endometrial cancer cells growth and its inhibitory effects on MCF-7 mammary cancer cells. The results clearly confirm our working hypothesis that the IGF system is involved in growth regulation of these cancer cells irrespective of the direction of the drug effect. The following par-ameters of the IGFs system were studied: IGF-I receptors, IGF-I stimulated protein tyrosine phosphorylation, and membrane-associated and secreted IGF-binding proteins (IGFBPs). In Ishikawa cells, tamoxifen, similar to estradiol, increased IGF-I stimulated tyrosine phosphorylation of cellular substrates in accordance with its effect on cell growth. This effect of tamoxifen was inverted in MCF-7 cells. Tamoxifen did not affect the number or affinity of IGF-I receptors in both Ishikawa and MCF-7 cells, however, it caused a three-fold decrease in membrane-associated IGFBPs in the endometrial cells but an increase in these proteins in breast cancer cells. Similar but much less pronounced changes in soluble IGFBPs were observed. Our results indicate that the opposing growth effects of tamoxifen on endometrial and mammary cancer cells are associated with modulation of the IGF system components, mainly with reciprocal changes in membrane-associated IGFBPs.

Original languageEnglish (US)
Pages (from-to)513-520
Number of pages8
JournalProgress in Growth Factor Research
Volume6
Issue number2-4
DOIs
StatePublished - 1995
Externally publishedYes

Fingerprint

Cell growth
Tamoxifen
Endometrial Neoplasms
Insulin-Like Growth Factor Binding Proteins
Cells
Breast Neoplasms
Growth
IGF Type 1 Receptor
Phosphorylation
Membranes
Insulin-Like Growth Factor I
Tyrosine
MCF-7 Cells
Membrane Proteins
Estradiol
Proteins
Modulation
Hormones
Substrates
Growth Hormone

Keywords

  • endometrial cancer
  • IGF-I receptor
  • IGFBPs
  • Tamoxifen
  • tyrosine phosphorylation

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology
  • Endocrinology, Diabetes and Metabolism
  • Immunology and Allergy

Cite this

Components of the IGF system mediate the opposing effects of tamoxifen on endometrial and breast cancer cell growth. / Karas, Michael; Kleinman, Dita; Danilenko, Michael; Roberts, Charles; LeRoith, Derek; Levy, Joseph; Sharoni, Yoav.

In: Progress in Growth Factor Research, Vol. 6, No. 2-4, 1995, p. 513-520.

Research output: Contribution to journalArticle

Karas, Michael ; Kleinman, Dita ; Danilenko, Michael ; Roberts, Charles ; LeRoith, Derek ; Levy, Joseph ; Sharoni, Yoav. / Components of the IGF system mediate the opposing effects of tamoxifen on endometrial and breast cancer cell growth. In: Progress in Growth Factor Research. 1995 ; Vol. 6, No. 2-4. pp. 513-520.
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