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Activation of the human androgen receptor through a protein kinase A signaling pathway

L V Nazareth1, N L Weigel

  • 1Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA.

The Journal of Biological Chemistry
|August 16, 1996
PubMed

Insights

Protein kinase A activators can trigger androgen receptor (AR) activity without androgens, driving prostate cancer progression. Inhibiting this pathway shows promise for novel prostate cancer therapies.

Area of Science:

  • Molecular Biology
  • Oncology
  • Cell Signaling

Background:

  • Aberrant androgen receptor (AR) activation, independent of androgens, drives prostate tumor progression to an androgen-independent state.
  • Understanding AR signaling pathways is crucial for developing effective prostate cancer treatments.

Purpose of the Study:

  • To investigate the effects of protein kinase A (PKA) modulators on human AR activity.
  • To explore the role of ligand-independent AR activation in prostate cancer progression.

Main Methods:

  • Adenoviral DNA delivery system used for co-transfection of AR and androgen-responsive reporters in CV1 and PC-3 cells.
  • Immunoblotting to assess AR protein levels.
  • Treatment with PKA activator (forskolin) and inhibitor peptide, as well as anti-androgens (casodex, flutamide).
  • Utilized AR mutants with varying DNA binding abilities.

Main Results:

  • Forskolin activated AR in the absence of androgens, independent of changes in AR protein levels.
  • PKA inhibitor peptide blocked forskolin-induced AR activation.
  • Anti-androgens significantly reduced this ligand-independent AR activation.
  • An intact AR DNA binding domain was essential for this alternate signaling pathway.

Conclusions:

  • PKA signaling can activate the androgen receptor independently of androgens, contributing to prostate cancer progression.
  • The phosphorylation status of AR or associated proteins may modulate AR activity.
  • Targeting PKA-mediated AR activation presents a potential therapeutic strategy for prostate cancer.

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