scholarly journals Transcription of Nrdp1 by the androgen receptor is regulated by nuclear filamin A in prostate cancer

2015 ◽  
Vol 22 (3) ◽  
pp. 369-386 ◽  
Author(s):  
Rosalinda M Savoy ◽  
Liqun Chen ◽  
Salma Siddiqui ◽  
Frank U Melgoza ◽  
Blythe Durbin-Johnson ◽  
...  

Prostate cancer (PCa) progression is regulated by the androgen receptor (AR); however, patients undergoing androgen-deprivation therapy (ADT) for disseminated PCa eventually develop castration-resistant PCa (CRPC). Results of previous studies indicated thatAR, a transcription factor, occupies distinct genomic loci in CRPC compared with hormone-naïve PCa; however, the cause of this distinction was unknown. The E3 ubiquitin ligaseNrdp1is a model AR target modulated by androgens in hormone-naïve PCa but not in CRPC. UsingNrdp1, we investigated how AR switches transcription programs during CRPC progression. The proximalNrdp1promoter contains an androgen response element (ARE); we demonstrated AR binding to this ARE in androgen-sensitive PCa. Analysis of hormone-naive human prostatectomy specimens revealed correlation betweenNrdp1and AR expression, supporting AR regulation of NRDP1 levels in androgen-sensitive tissue. However, despite sustained AR levels, AR binding to theNrdp1promoter andNrdp1expression were suppressed in CRPC. Elucidation of the suppression mechanism demonstrated correlation of NRDP1 levels with nuclear localization of the scaffolding protein filamin A (FLNA) which, as we previously showed, is itself repressed following ADT in many CRPC tumors. Restoration of nuclear FLNA in CRPC stimulated AR binding toNrdp1ARE, increased its transcription, and augmented NRDP1 protein expression and responsiveness to ADT, indicating that nuclear FLNA controls AR-mediated androgen-sensitiveNrdp1transcription. Expression of other AR-regulated genes lost in CRPC was also re-established by nuclear FLNA. Thus, our results indicate that nuclear FLNA promotes androgen-dependent AR-regulated transcription in PCa, while loss of nuclear FLNA in CRPC alters the AR-regulated transcription program.

2019 ◽  
Vol 19 (5) ◽  
pp. 368-381 ◽  
Author(s):  
Linh N.K. Tran ◽  
Ganessan Kichenadasse ◽  
Pamela J. Sykes

Prostate cancer (PCa) is the most frequent cancer in men. The evolution from local PCa to castration-resistant PCa, an end-stage of disease, is often associated with changes in genes such as p53, androgen receptor, PTEN, and ETS gene fusion products. Evidence is accumulating that repurposing of metformin (MET) and valproic acid (VPA) either when used alone, or in combination, with another therapy, could potentially play a role in slowing down PCa progression. This review provides an overview of the application of MET and VPA, both alone and in combination with other drugs for PCa treatment, correlates the responses to these drugs with common molecular changes in PCa, and then describes the potential for combined MET and VPA as a systemic therapy for prostate cancer, based on potential interacting mechanisms.


2019 ◽  
Vol 20 (9) ◽  
pp. 2066 ◽  
Author(s):  
Namrata Khurana ◽  
Suresh C. Sikka

Androgen receptor (AR) signaling plays a key role not only in the initiation of prostate cancer (PCa) but also in its transition to aggressive and invasive castration-resistant prostate cancer (CRPC). However, the crosstalk of AR with other signaling pathways contributes significantly to the emergence and growth of CRPC. Wnt/β-catenin signaling facilitates ductal morphogenesis in fetal prostate and its anomalous expression has been linked with PCa. β-catenin has also been reported to form complex with AR and thus augment AR signaling in PCa. The transcription factor SOX9 has been shown to be the driving force of aggressive and invasive PCa cells and regulate AR expression in PCa cells. Furthermore, SOX9 has also been shown to propel PCa by the reactivation of Wnt/β-catenin signaling. In this review, we discuss the critical role of SOX9/AR/Wnt/β-catenin signaling axis in the development and progression of CRPC. The phytochemicals like sulforaphane and curcumin that can concurrently target SOX9, AR and Wnt/β-catenin signaling pathways in PCa may thus be beneficial in the chemoprevention of PCa.


2017 ◽  
Vol 28 (9) ◽  
pp. 2264-2271 ◽  
Author(s):  
D.E. Rathkopf ◽  
M.R. Smith ◽  
C.J. Ryan ◽  
W.R. Berry ◽  
N.D. Shore ◽  
...  

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