title: ARF represses androgen receptor transactivation in prostate cancer.
abstract: Androgen receptor (AR) signaling is essential for prostate cancer (PCa) development in humans. The initiation of prostate malignancy and progression to a castration-resistant stage are largely contributed by the modulation of AR activity through its coregulatory proteins. We and others previously reported that p14 alternative reading frame (ARF) expression is positively correlated with the disease progression and severity of PCa. Here, we provide evidence that p14ARF physically interacts with AR and functions as an AR corespressor in both an androgen-dependent and androgen-independent manner. Endogenous ARF (p14ARF in human and p19ARF in mouse) and AR colocalize in both human PCa cells in vitro and PCa tissues of mouse and human in vivo. Overexpression of p14ARF in PCa cells significantly attenuates the activities of androgen response region (ARR2)-probasin and prostate-specific antigen (PSA) promoters. The forced expression of p14ARF in cells resulted in a suppression of PSA and NK transcription factor locus 1 (NKX3.1) expression. Conversely, knockdown of endogenous p14ARF in human PCa cells with short hairpin RNA enhanced AR transactivation activities in a dose-dependent and p53-independent manner. Furthermore, we demonstrated that p14ARF binds to both the N-terminal domain and the ligand-binding domain of AR, and the human double minute 2 (HDM2)-binding motif of p14ARF is required for the interaction of p14ARF and AR proteins. p14ARF perturbs the androgen-induced interaction between the N terminus and C terminus of AR. Most importantly, we observed that the expression of PSA is reversely correlated with p14ARF in human prostate tissues. Taken together, our results reveal a novel function of ARF in modulation of AR transactivation in PCa.
authors: Department of Biochemistry and Cancer Biology, Meharry Medical College, 1005 Dr D. B. Todd Jr Boulevard, Nashville, Tennessee 37208, USA.
authors: Wenfu
authors: W
authors: Lu
authors: Yingqiu
authors: Y
authors: Xie
authors: Yufang
authors: Y
authors: Ma
authors: Robert J
authors: RJ
authors: Matusik
authors: Zhenbang
authors: Z
authors: Chen
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011467:Prostate / Q000378:metabolism / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D011485:Protein Binding; D021381:Protein Transport; D011944:Receptors, Androgen / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics*; D025803:Tumor Suppressor Protein p14ARF / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018398:Homeodomain Proteins; D011944:Receptors, Androgen; D012097:Repressor Proteins; D025803:Tumor Suppressor Protein p14ARF; D017430:Prostate-Specific Antigen