5-Androstenediol promotes survival of gamma-irradiated human hematopoietic progenitors through induction of nuclear factor-kappaB activation and granulocyte colony-stimulating factor expression

Mol Pharmacol. 2007 Aug;72(2):370-9. doi: 10.1124/mol.107.035394. Epub 2007 May 1.

Abstract

5-Androstenediol (5-AED) stimulates hematopoiesis and enhances survival in animals exposed to ionizing radiation (IR), suggesting that this steroid may act on hematopoietic progenitor cells. We used gamma-irradiated primary human CD34(+) hematopoietic progenitor cells to show that 5-AED protects hematopoietic cells from IR damage, as shown by enhanced cell survival, clonogenicity, proliferation, and differentiation. Unlike in tumor cells, IR did not induce nuclear factor-kappaB (NFkappaB) activation in primary progenitors. However, IR stimulated IkappaB(beta) release from NFkappaB/IkappaB complexes and caused NFkappaB1 (p50) degradation. 5-AED stabilized NFkappaB1 in irradiated cells and induced NFkappaB gene expression and NFkappaB activation (DNA binding). 5-AED stimulated interleukin-6 and granulocyte colony-stimulating factor (G-CSF) secretion. The survival-enhancing effects of 5-AED on clonogenic cells were abrogated by small interfering RNA inhibition of NFkappaB gene expression and by neutralization of G-CSF with antibody. The effects of 5-AED on survival and G-CSF secretion were blocked by the NFkappaB inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG132). 5-AED had no effect on accumulation of the proapoptotic factor p53 after IR, as determined by Western blot. The results indicate that NFkappaB1 degradation after IR may be responsible for the radiation sensitivity of CD34+ cells compared with tumor cells. 5-AED exerts survival-enhancing effects on irradiated human hematopoietic progenitor cells via induction, stabilization, and activation of NFkappaB, which results in increased secretion of hematopoietic growth factor G-CSF.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Androstenediol / pharmacology*
  • Antigens, CD34 / analysis
  • Cell Differentiation / drug effects
  • Cell Survival / drug effects*
  • Cells, Cultured
  • DNA-Activated Protein Kinase / physiology
  • Gamma Rays
  • Granulocyte Colony-Stimulating Factor / physiology*
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / drug effects*
  • Humans
  • I-kappa B Proteins / metabolism
  • Interleukin-6 / physiology
  • NF-kappa B / genetics
  • NF-kappa B / physiology*
  • Tumor Suppressor Protein p53 / physiology

Substances

  • Antigens, CD34
  • I kappa B beta protein
  • I-kappa B Proteins
  • Interleukin-6
  • NF-kappa B
  • Tumor Suppressor Protein p53
  • Granulocyte Colony-Stimulating Factor
  • Androstenediol
  • DNA-Activated Protein Kinase