title: PAGE4 positivity is associated with attenuated AR signaling and predicts patient survival in hormone-naive prostate cancer.
abstract: Aberrant activation of the androgen receptor (AR) plays a key role during prostate cancer (PCa) development and progression to castration-resistant prostate cancer (CR-PCa) after androgen deprivation therapy, the mainstay systemic treatment for PCa. New strategies to abrogate AR activity and biomarkers that predict aggressive tumor behavior are essential for improved therapeutic intervention. PCa tissue microarrays herein reveal that prostate-associated gene 4 (PAGE4), an X-linked cancer/testis antigen, is highly up-regulated in the epithelium of preneoplastic lesions compared with benign epithelium, but subsequently decreases with tumor progression. We show that AR signaling is attenuated in PAGE4-expressing cells both in vitro and in vivo, most likely via impaired androgen-induced AR nuclear translocation and subsequently reduced AR protein stabilization and phosphorylation at serines 81 and 213. Consistently, epithelial PAGE4 protein levels inversely correlated with AR activation status in hormone-naive and CR-PCa clinical specimens. Moreover, PAGE4 impaired the development of CR-PCa xenografts, and strong PAGE4 immunoreactivity independently predicted favorable patient survival in hormone-naive PCa. Collectively, these data suggest that dysregulation of epithelial PAGE4 modulates AR signaling, thereby promoting progression to advanced lethal PCa and highlight the potential value of PAGE4 as a prognostic and therapeutic target.
authors.affiliation: Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck, Austria. natalie.sampson@oeaw.ac.at
authors.forename: Natalie
authors.initials: N
authors.lastname: Sampson
authors.forename: Christian
authors.initials: C
authors.lastname: Ruiz
authors.forename: Christoph
authors.initials: C
authors.lastname: Zenzmaier
authors.forename: Lukas
authors.initials: L
authors.lastname: Bubendorf
authors.forename: Peter
authors.initials: P
authors.lastname: Berger
mesh_terms: D000728:Androgens / Q000494:pharmacology*; D000813:Anilides / Q000494:pharmacology; D000818:Animals; D000951:Antigens, Neoplasm / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D018450:Disease Progression; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D055785:Gene Knockdown Techniques; D006801:Humans; D008024:Ligands; D008297:Male; D051379:Mice; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D055550:Protein Stability / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011944:Receptors, Androgen / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D016019:Survival Analysis; D014105:Tosyl Compounds / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
chemical_list: C410798:AR protein, human; D000728:Androgens; D000813:Anilides; D000951:Antigens, Neoplasm; D008024:Ligands; D009570:Nitriles; C474505:PAGE4 protein, human; D011944:Receptors, Androgen; D011965:Receptors, Glucocorticoid; D014105:Tosyl Compounds; C053541:bicalutamide