Androgen receptor promotes ligand-independent prostate cancer progression through c-Myc upregulation

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Androgen receptor (AR) signaling is central to prostate cancer, with androgen deprivation therapy (ADT) as a primary treatment.
• Resistance to ADT and tumor progression are significant challenges in prostate cancer management.
• AR can promote cancer growth independently of its ligands, but the specific target genes involved are not fully understood.

Purpose of the Study:

• To identify key ligand-independent AR target genes driving prostate cancer growth.
• To investigate the role of c-Myc as a ligand-independent AR target gene.
• To evaluate the therapeutic potential of targeting the AR-c-Myc pathway.

Main Methods:

• Microarray analysis to correlate AR and c-Myc expression in castration-resistant prostate cancer (CRPC) tumors.
• Experimental validation of direct AR regulation of c-Myc transcription.
• Assessment of the impact of AR and c-Myc suppression on prostate cancer cell growth.
• Evaluation of bromodomain inhibitor JQ1 in suppressing c-Myc function and cancer cell survival.

Main Results:

• c-Myc was identified as a key ligand-independent AR target gene.
• AR and c-Myc expression levels were strongly correlated in CRPC tumors.
• AR directly regulates c-Myc transcription independently of AR ligands.
• Suppression of AR and c-Myc inhibited prostate cancer cell growth, while c-Myc overexpression counteracted AR suppression effects.
• JQ1 treatment inhibited c-Myc function and prostate cancer cell survival.

Conclusions:

• A novel link between AR and c-Myc in ligand-independent prostate cancer growth was established.
• Targeting both AR and c-Myc presents a promising therapeutic strategy for improving prostate cancer control, particularly in CRPC.
• This study highlights the potential of targeting the AR-c-Myc axis for overcoming treatment resistance.