Proximity-dependent Mapping of the Androgen Receptor Identifies Kruppel-like Factor 4 as a Functional Partner

Area of Science:

• Oncology
• Molecular Biology
• Proteomics

Background:

• Prostate cancer (PCa) is a leading cancer diagnosis and cause of cancer mortality in men.
• Androgen receptor (AR) signaling, driven by androgens like testosterone, is critical for PCa initiation, proliferation, and survival.

Purpose of the Study:

• To comprehensively map the AR signaling network in androgen-dependent prostate cancer cells.
• To identify novel AR-associated proteins and understand their roles in AR signaling.

Main Methods:

• Utilized BioID proximity labeling proteomics in LAPC4 cells under varying androgen stimulation durations (0, 24, and 72 hours).
• Identified and quantified AR-associated proteins using mass spectrometry.
• Validated interactions and genomic colocalization for key factors like KLF4.

Main Results:

• Identified 31 AR-associated proteins in unstimulated cells, expanding to 182 and 200 proteins after 24h and 72h of androgen stimulation, respectively.
• Discovered 213 novel AR-associated proteins not previously documented, many involved in DNA metabolism, RNA processing, and transcription.
• Identified 44 transcription factors, including KLF4, interacting with AR; KLF4 was found to repress AR-dependent KLK3 (PSA) gene transcription and colocalize with AR genome-wide.

Conclusions:

• Generated an expanded, high-confidence proximity interactome for the androgen receptor.
• The identified novel AR-associated proteins offer new targets for understanding and potentially treating prostate cancer.
• This network provides a foundation for dissecting the intricate molecular mechanisms of androgen signaling in PCa.