scholarly journals A Splicing Variant of the Androgen Receptor Detected in a Metastatic Prostate Cancer Exhibits Exclusively Cytoplasmic Actions

Endocrinology ◽  
2007 ◽  
Vol 148 (9) ◽  
pp. 4334-4343 ◽  
Author(s):  
Monika Jagla ◽  
Marie Fève ◽  
Pascal Kessler ◽  
Gaëlle Lapouge ◽  
Eva Erdmann ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cancer Progression ◽  
Metastatic Prostate Cancer ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Splicing Variant ◽  
Activation Of Transcription

The androgen receptor (AR) is a ligand-activated transcription factor that displays genomic actions characterized by binding to androgen-response elements in the promoter of target genes as well as nongenomic actions that do not require nuclear translocation and DNA binding. In this study, we report exclusive cytoplasmic actions of a splicing variant of the AR detected in a metastatic prostate cancer. This AR variant, named AR23, results from an aberrant splicing of intron 2, wherein the last 69 nucleotides of the intronic sequence are retained, leading to the insertion of 23 amino acids between the two zinc fingers in the DNA-binding domain. We show that the nuclear entry of AR23 upon dihydrotestosterone (DHT) stimulation is impaired. Alternatively, DHT-activated AR23 forms cytoplasmic and perinuclear aggregates that partially colocalize with the endoplasmic reticulum and are devoid of genomic actions. However, in LNCaP cells, this cytoplasmic DHT-activated AR23 remains partially active as evidenced by the activation of transcription from androgen-responsive promoters, the stimulation of NF-κB transcriptional activity and by the decrease of AP-1 transcriptional activity. Our data reveal novel cytoplasmic actions for this splicing AR variant, suggesting a contribution in prostate cancer progression.

scholarly journals Differential modulation of the androgen receptor for prostate cancer therapy depends on the DNA response element

2020 ◽  
Vol 48 (9) ◽  
pp. 4741-4755
Author(s):  
Steven Kregel ◽  
Pia Bagamasbad ◽  
Shihan He ◽  
Elizabeth LaPensee ◽  
Yemi Raji ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Progression ◽  
Target Genes ◽  
Normal Growth ◽  
Differential Modulation ◽  
Expression Of Genes ◽  
Prostate Cancer Therapy ◽  
Specific Factors

Abstract Androgen receptor (AR) action is a hallmark of prostate cancer (PCa) with androgen deprivation being standard therapy. Yet, resistance arises and aberrant AR signaling promotes disease. We sought compounds that inhibited genes driving cancer but not normal growth and hypothesized that genes with consensus androgen response elements (cAREs) drive proliferation but genes with selective elements (sAREs) promote differentiation. In a high-throughput promoter-dependent drug screen, doxorubicin (dox) exhibited this ability, acting on DNA rather than AR. This dox effect was observed at low doses for multiple AR target genes in multiple PCa cell lines and also occurred in vivo. Transcriptomic analyses revealed that low dox downregulated cell cycle genes while high dox upregulated DNA damage response genes. In chromatin immunoprecipitation (ChIP) assays with low dox, AR binding to sARE-containing enhancers increased, whereas AR was lost from cAREs. Further, ChIP-seq analysis revealed a subset of genes for which AR binding in low dox increased at pre-existing sites that included sites for prostate-specific factors such as FOXA1. AR dependence on cofactors at sAREs may be the basis for differential modulation by dox that preserves expression of genes for survival but not cancer progression. Repurposing of dox may provide unique opportunities for PCa treatment.

scholarly journals Activation of GPR56, a novel adhesion GPCR, is necessary for nuclear androgen receptor signaling in prostate cells

2019 ◽  
Author(s):  
Julie Pratibha Singh ◽  
Manisha Dagar ◽  
Gunjan Dagar ◽  
Sudhir Rawal ◽  
Ravi Datta Sharma ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Intracellular Signaling ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Prostate Tumor ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Pka Pathway ◽  
Adhesion Gpcr

AbstractThe androgen receptor (AR) is activated in patients with castration resistant prostate cancer (CRPC) despite low circulating levels of androgen, suggesting that intracellular signaling pathways and non-androgenic factors may contribute to AR activation. Many G-protein coupled receptors (GPCR) and their ligands are also activated in these cells indicating a role for these in CRPC. Although a cross talk has been suggested between the two pathways, yet, the identity of GPCRs which may play a role in androgen signaling, is not established yet. We demonstrate that adhesion GPCR 205, also known as GPR56, can be activated by androgens to stimulate the Rho signaling pathway, a pathway that plays an important role in prostate tumor cell metastasis. Testosterone stimulation of GPR56 also activates the cAMP/ Protein kinase A (PKA) pathway, that is necessary for AR signaling. Knocking down the expression of GPR56 using siRNA, disrupts nuclear translocation of AR and transcription of prototypic AR target genes such as PSA. GPR56 expression is higher in all prostate tumor samples tested and cells expressing GPR56 exhibit increased proliferation. These findings provide new insights about androgen signaling and identify GPR56 as a possible therapeutic target in advanced prostate cancer patients.

Activation of PSGR with β-ionone suppresses prostate cancer progression by blocking androgen receptor nuclear translocation

2019 ◽  
Vol 453 ◽  
pp. 193-205 ◽  
Author(s):  
Hongjun Xie ◽  
Tianjie Liu ◽  
Jiaqi Chen ◽  
Zhao Yang ◽  
Shan Xu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Progression ◽  
Nuclear Translocation ◽  
Prostate Cancer Progression

scholarly journals ARVib suppresses growth of advanced prostate cancer via inhibition of androgen receptor signaling

Oncogene ◽  
2021 ◽  
Author(s):  
Chengfei Liu ◽  
Cameron M. Armstrong ◽  
Shu Ning ◽  
Joy C. Yang ◽  
Wei Lou ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Progression ◽  
Nuclear Translocation ◽  
Treatment Resistance ◽  
Hsp70 Expression ◽  
Castration Resistant Prostate Cancer ◽  
Downstream Target

AbstractTargeting androgen signaling with the second-generation anti-androgen drugs, such as enzalutamide (Enza), abiraterone (Abi), apalutamide (Apal), and darolutamide (Daro), is the mainstay for the treatment of castration-resistant prostate cancer (CRPC). While these treatments are effective initially, resistance occurs frequently. Continued expression of androgen receptor (AR) and its variants such as AR-V7 despite AR-targeted therapy contributes to treatment resistance and cancer progression in advanced CRPC patients. This highlights the need for new strategies blocking continued AR signaling. Here, we identify a novel AR/AR-V7 degrader (ARVib) and found that ARVib effectively degrades AR/AR-V7 protein and attenuates AR/AR-V7 downstream target gene expression in prostate cancer cells. Mechanistically, ARVib degrades AR/AR-V7 protein through the ubiquitin-proteasome pathway mediated by HSP70/STUB1 machinery modulation. ARVib suppresses HSP70 expression and promotes STUB1 nuclear translocation, where STUB1 binds to AR/AR-V7 and promotes its ubiquitination and degradation. ARVib significantly inhibits resistant prostate tumor growth and improves enzalutamide treatment in vitro and in vivo. These data suggest that ARVib has potential for development as an AR/AR-V7 degrader to treat resistant CRPC.

scholarly journals Influence of nucleophosmin/B23 on DNA binding and transcriptional activity of the androgen receptor in prostate cancer cell

Oncogene ◽  
2007 ◽  
Vol 27 (20) ◽  
pp. 2858-2867 ◽  
Author(s):  
L Léotoing ◽  
L Meunier ◽  
M Manin ◽  
C Mauduit ◽  
M Decaussin ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cancer Cell ◽  
Transcriptional Activity ◽  
Prostate Cancer Cell

scholarly journals Low K+ Promotes NF-κB/DNA Binding in Neuronal Apoptosis Induced by K+ Loss

2006 ◽  
Vol 26 (3) ◽  
pp. 1038-1050 ◽  
Author(s):  
Yanmei Tao ◽  
Dong Yan ◽  
Qiaoyun Yang ◽  
Rui Zeng ◽  
Yizheng Wang
Keyword(s):  
Dna Binding ◽  
Cortical Neurons ◽  
Neuronal Apoptosis ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Direct Action ◽  
Direct Effects ◽  
Proapoptotic Protein ◽  
Low K

ABSTRACT Low intracellular K+ concentration ([K+]i) promotes apoptosis and blocking K+ loss prevents apoptosis, but the mechanism of action of low [K+]i remains unclear. Here, we show that low [K+]i increases NF-κB transcriptional activity by enhancing its binding to the promoter of target genes without affecting its activation and nuclear translocation in cortical neurons deprived of serum. Low K+ concentration promotes NF-κB/DNA binding through direct effects on the interaction of NF-κB dimers with DNA. Up-regulation of proapoptotic protein Bcl-XS and neuronal apoptosis induced by serum deprivation are blocked by inhibition and/or down-regulation of NF-κB and by prevention of K+ loss. Thus, a direct action of K+ on NF-κB/DNA binding regulates gene transcription related to neuronal apoptosis.

The androgen receptor DNA-binding domain determines androgen selectivity of transcriptional response

2006 ◽  
Vol 34 (6) ◽  
pp. 1089-1094 ◽  
Author(s):  
G. Verrijdt ◽  
T. Tanner ◽  
U. Moehren ◽  
L. Callewaert ◽  
A. Haelens ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cellular Response ◽  
Hormone Receptors ◽  
Target Genes ◽  
Steroid Hormone ◽  
Prostate Gland ◽  
Steroid Hormone Receptors ◽  
Binding Motif

The AR (androgen receptor) is a hormone-dependent transcription factor that translates circulating androgen hormone levels into a physiological cellular response by directly regulating the expression of its target genes. It is the key molecule in e.g. the development and maintenance of the male sexual characteristics, spermatocyte production and prostate gland development and growth. It is also a major factor in the onset and maintenance of prostate cancer and a first target for pharmaceutical action against the further proliferation of prostate cancer cells. The AR is a member of the steroid hormone receptors, a group of steroid-inducible transcription factors sharing an identical consensus DNA-binding motif. The problem of how specificity in gene activation is achieved among the different members of this nuclear receptor subfamily is still unclear. In this report, we describe our investigations on how the AR can specifically activate its target genes, while the other steroid hormone receptors do not, despite having the same consensus monomeric DNA-binding motif. In this respect, we describe how the AR interacts with a newly identified class of steroid-response elements to which only the AR and not, for example, the glucocorticoid receptor can bind.

scholarly journals Inhibition of Androgen Receptor Transcriptional Activity as a Novel Mechanism of Action of Arsenic

2009 ◽  
Vol 23 (3) ◽  
pp. 412-421 ◽  
Author(s):  
Adena E. Rosenblatt ◽  
Kerry L. Burnstein
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Male Infertility ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Nuclear Translocation ◽  
Therapeutic Option ◽  
Protein Levels

Abstract Environmental sodium arsenite is a toxin that is associated with male infertility due to decreased and abnormal sperm production. Arsenic trioxide (ATO), another inorganic trivalent semimetal, is an effective therapy for acute promyelocytic leukemia, and there is investigation of its possible efficacy in prostate cancer. However, the mechanism of arsenic action in male urogenital tract tissues is not clear. Because the androgen receptor (AR) plays an important role in spermatogenesis and prostate cancer, we explored the possibility that trivalent arsenic regulates AR function. We found that arsenic inhibited AR transcriptional activity in prostate cancer and Sertoli cells using reporter gene assays testing several androgen response element-containing regions and by assessing native target gene expression. Arsenic inhibition of AR activity was not due to down-regulation of AR protein levels, decreased hormone binding to AR, disruption of AR nuclear translocation, or interference with AR-DNA binding in vitro. However, chromatin immunoprecipitation studies revealed that arsenic inhibited AR recruitment to an AR target gene enhancer in vivo. Consistent with a deficiency in AR-chromatin binding, arsenic disrupted AR amino and carboxyl termini interaction. Furthermore, ATO caused a significant decrease in prostate cancer cell proliferation that was more pronounced in cells expressing AR compared with cells depleted of AR. In addition, inhibition of AR activity by ATO and by the AR antagonist, bicalutamide, was additive. Thus, arsenic-induced male infertility may be due to inhibition of AR activity. Further, because AR is an important target in prostate cancer therapy, arsenic may serve as an effective therapeutic option.

Sign in / Sign up

Export Citation Format

Share Document