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EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation.

Author:
  • Susann Reinbothe
  • Anna-Maria Larsson
  • Marica Vaapil
  • Caroline Wigerup
  • Jianmin Sun
  • Annika Jögi
  • Drorit Neumann
  • Lars Rönnstrand
  • Sven Påhlman
Publishing year: 2014
Language: English
Pages: 163-169
Publication/Series: Biochemical and Biophysical Research Communications
Volume: 445
Issue: 1
Document type: Journal article
Publisher: Elsevier

Abstract english

The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα(+)) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells.

Keywords

  • Biological Sciences

Other

Published
  • ISSN: 1090-2104
Sven Påhlman
E-mail: sven [dot] pahlman [at] med [dot] lu [dot] se

Professor

Division of Translational Cancer Research

+46 46 222 64 21

MV406 312K1

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