Androgen receptor down regulation by small interference RNA induces cell growth inhibition in androgen sensitive as well as in androgen independent prostate cancer cells

J Steroid Biochem Mol Biol. 2005 Aug;96(3-4):251-8. doi: 10.1016/j.jsbmb.2005.04.029.


We investigated the effects of androgen receptor (AR) down regulation with a small interference RNA molecule (siRNA_AR(start)) on androgen sensitive LNCaP and androgen independent LNCaPabl prostate cancer cells, the latter representing an in vitro model for the development of therapy resistance in prostate cancer. Although LNCaPabl cells express increased levels of AR in comparison with androgen sensitive LNCaP cells, the protein was significantly down regulated in response to siRNA_AR(start) treatment. This AR down regulation resulted in a marked cell growth inhibition in both cell lines. By contrast, DU-145 prostate cancer cells, which lack AR expression, were not inhibited by the siRNA_AR(start). In consequence to AR down regulation, both cell lines, LNCaP and LNCaPabl, shared a highly similar gene expression profile in terms of major changes in cell cycle regulatory genes. The cell cycle inhibitor p21(Waf1/Cip1) as well as cyclin D1 were significantly up regulated by siRNA_AR(start) treatment, considering a switch in cyclin expression towards cell cycle retardation. Control molecules had moderate effects on cell proliferation and gene expression, respectively. In summary, we found that AR inhibition with siRNA induces cell growth retardation in androgen sensitive as well as in androgen independent prostate cancer cells and thus may represent an interesting approach to combat hormone-refractory prostate cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androgen Receptor Antagonists*
  • Androgens / metabolism
  • Cell Cycle Proteins / metabolism
  • Cell Proliferation / drug effects
  • Cyclin D1 / metabolism
  • Cyclin-Dependent Kinase Inhibitor p21
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Male
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism
  • Prostatic Neoplasms / therapy*
  • RNA Interference*
  • RNA, Small Interfering / genetics
  • Receptors, Androgen / genetics
  • Receptors, Androgen / metabolism
  • Transfection
  • Tumor Cells, Cultured
  • Up-Regulation


  • Androgen Receptor Antagonists
  • Androgens
  • CDKN1A protein, human
  • Cell Cycle Proteins
  • Cyclin-Dependent Kinase Inhibitor p21
  • RNA, Small Interfering
  • Receptors, Androgen
  • Cyclin D1