Beta-2-microglobulin is an androgen-regulated secreted protein elevated in serum of patients with advanced prostate cancer.

Purpose: A better understanding of secreted proteins may lead to the discovery of new biomarkers, which, along with prostate-specific antigen (PSA), may be useful in the diagnosis and treatment of prostate cancer patients.

Experimental Design: Conditioned medium was collected from LNCaP cells following stimulation with methyltrienolone (R1881), 17beta-estradiol (estradiol), or interleukin-6 and analyzed for differential protein expression with surface-enhanced laser desorption/ionization-time of flight mass spectrometry. Quantitative reverse transcription-PCR, immunoblots, and ELISA were used to measure beta-2-microglobulin (B2M) message and protein levels in cells, conditioned medium, and serum.

PIASy-mediated repression of the androgen receptor is independent of sumoylation.

PIASy, a member of the protein inhibitor of activated STAT (PIAS) family, represses the transcriptional activity of the androgen receptor (AR). In this report, we investigate the mechanism of PIASy-mediated repression of AR. We show that AR binds to the RING-finger like domain of PIASy.