scholarly journals Development of Peptide Antagonists for the Androgen Receptor Using Combinatorial Peptide Phage Display

2005 ◽  
Vol 19 (10) ◽  
pp. 2478-2490 ◽  
Author(s):  
Ching-yi Chang ◽  
Jennifer Abdo ◽  
Tanya Hartney ◽  
Donald P. McDonnell
Keyword(s):  
Androgen Receptor ◽  
Phage Display ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Transcriptional Activity ◽  
Binding Pocket ◽  
Orphan Nuclear Receptors ◽  
Nuclear Receptor Coactivator ◽  
Pharmacological Significance ◽  
Peptide Phage Display

Abstract Under the auspices of the Nuclear Receptor Signaling Atlas (NURSA) , we have undertaken to evaluate the feasibility of targeting nuclear receptor-coactivator surfaces for new drug discovery. The underlying objective of this approach is to provide the research community with reagents that can be used to modulate the transcriptional activity of nuclear receptors. Using combinatorial peptide phage display, we have been able to develop peptide antagonists that target specific nuclear receptor (NR)-coactivator binding surfaces. It can be appreciated that reagents of this nature will be of use in the study of orphan nuclear receptors for whom classical ligands have not yet been identified. In addition, because the interaction of coactivators with the receptor is an obligate step for NR transcriptional activity, it is anticipated that peptides that block these interactions will enable the definition of the biological and pharmacological significance of individual NR-coactivator interactions. In this report, we describe the use of this approach to develop antagonists of the androgen receptor by targeting its coactivator-binding pocket and their use to study the coactivator-binding surface of this receptor. Based on our findings, we believe that molecules that function by disrupting the androgen receptor-cofactor interactions will have use in the treatment of prostate cancer.

scholarly journals Inactivation of the Nuclear Receptor Coactivator RAP250 in Mice Results in Placental Vascular Dysfunction

2003 ◽  
Vol 23 (4) ◽  
pp. 1260-1268 ◽  
Author(s):  
Per Antonson ◽  
Gertrud U. Schuster ◽  
Ling Wang ◽  
Björn Rozell ◽  
Elin Holter ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Blood Circulation ◽  
Transcriptional Activity ◽  
Vascular Dysfunction ◽  
Diverse Group ◽  
Placental Development ◽  
Nuclear Receptor Coactivator ◽  
The Past ◽  
Placental Blood

ABSTRACT Coactivators constitute a diverse group of proteins that are essential for optimal transcriptional activity of nuclear receptors. In the past few years many coactivators have been identified but it is still unclear whether these proteins interact indiscriminately with all nuclear receptors and whether there is some redundancy in their functions. We have previously cloned and characterized RAP250 (ASC-2/PRIP/TRBP/NRC), an LXXLL-containing coactivator for nuclear receptors. In order to study its biological role, Rap250 null mice were generated by gene targeting. Here we show that genetic disruption of Rap250 results in embryonic lethality at embryonic day (E) 13.5. Histological examination of placentas revealed a dramatically reduced spongiotrophoblast layer, a collapse of blood vessels in the region bordering the spongiotrophoblast, and labyrinthine layers in placentas from Rap250−/− embryos. These findings suggest that the lethality of Rap250−/− embryos is the result of obstructed placental blood circulation. Moreover, the transcriptional activity of PPARγ is reduced in fibroblasts derived from Rap250−/− embryos, suggesting that RAP250 is an essential coactivator for this nuclear receptor in the placenta. Our results demonstrate that RAP250 is necessary for placental development and thus essential for embryonic development.

scholarly journals SUN-LB138 Dynamic Structural Model of Testosterone Entry Into the Unliganded Androgen Receptor

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Irina Krylova ◽  
Fred J Schaufele ◽  
Christophe Guilbert
Keyword(s):  
Amino Acids ◽  
Androgen Receptor ◽  
Ligand Binding ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Binding Pocket ◽  
Binding Domain ◽  
Receptor Ligand ◽  
Ligand Binding Pocket ◽  
Crystallographic Structures

Abstract Background: Crystallographic structures of nuclear receptor ligand binding domains provide a static model of a receptor stably wrapped around an internalized ligand. Understanding the dynamics of a receptor at different stages of ligand binding has been hampered by the paucity of crystal structures for unliganded nuclear receptors. Molecular dynamic models have been constructed for some nuclear receptors to fill that void. Methods: The molecular simulation docking program MORDOR (MOlecular Recognition with a Driven dynamics OptimizeR)(1) was used to study the structural dynamics of the androgen receptor ligand binding domain (AR LBD) modeled from the static structure of the AR LBD bound to testosterone (T) (PDB ID: 2AM9). The goals of the study were to understand a) the dynamic interaction of the T in its binding pocket, b) AR LBD structural flexibilities that permit T entry/exit from the binding pocket and c) a model of the unliganded AR LBD. Results: Modeling AR LBD structure flexibility over time revealed possible alternative dynamic structures, including those without ligand, overlaid against the canonical nuclear receptor structure. The model dynamically tracks the structural changes as a ligand enters into the ligand binding domain and nestles into the ligand binding pocket. The model predicted the appearance of alpha helices within the AR LBD that transiently fold/unfold during the ligand entry phases. Once in the pocket, the ligand itself remains very dynamic in a still flexible pocket. The model predicted also AR LBD amino acids that sequentially interact with the ligand during its dynamic entry into the AR LBD. Intriguingly, those AR amino acids include those mutated in castration-resistant prostate tumors that continue to grow during androgen suppression therapy. Functional studies showed those mutant ARs had a primary consequence of enhancing response to lower level T, and other androgens, consistent with their role in creating a higher affinity AR that can scavenge low-level androgens in an androgen-suppressed patient. Conclusions: The molecular model of T binding to the AR LBD suggests a degree of structural dynamism not evident in the crystallographic structures commonly associated with nuclear receptors. Some AR mutations activating prostate tumor growth may do so by impacting androgen entry/exit, rather than by altering androgen fit into the ligand binding pocket. Reference: (1) Guilbert C, James TL (2008) J Chem Inf Model. 2008 48(6): 1257-1268. doi: 10.1021/ci8000327

scholarly journals Identification of a nuclear receptor/coactivator developmental signaling pathway in the nematode parasite Strongyloides stercoralis

2021 ◽  
Vol 118 (8) ◽  
pp. e2021864118
Author(s):  
Mi Cheong Cheong ◽  
Zhu Wang ◽  
Tegegn G. Jaleta ◽  
Xinshe Li ◽  
James B. Lok ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Nuclear Receptor ◽  
Transcriptional Activity ◽  
Strongyloides Stercoralis ◽  
Parasite Development ◽  
Binding Motif ◽  
Nuclear Receptor Coactivator ◽  
Interacting Protein ◽  
Third Stage ◽  
Infectious Stage

DAF-12 is nematode-specific nuclear receptor that has been proposed to govern development of the infectious stage of parasitic species, including Strongyloides stercoralis. Here, we identified a parasite-specific coactivator, called DAF-12 interacting protein-1 (DIP-1), that is required for DAF-12 ligand-dependent transcriptional activity. DIP-1 is found only in Strongyloides spp. and selectively interacts with DAF-12 through an atypical receptor binding motif. Using CRISPR/Cas9-directed mutagenesis, we demonstrate that DAF-12 is required for the requisite developmental arrest and the ligand-dependent reactivation of infectious S. stercoralis infective third-stage larvae, and that these effects require the DIP-1 coactivator. These studies reveal the existence of a distinct nuclear receptor/coactivator signaling pathway that governs parasite development.

scholarly journals Potentiation of androgen receptor transcriptional activity by inhibition of histone deacetylation--rescue of transcriptionally compromised mutants

2004 ◽  
Vol 182 (3) ◽  
pp. 377-389 ◽  
Author(s):  
CG Korkmaz ◽  
K Fronsdal ◽  
Y Zhang ◽  
PI Lorenzo ◽  
F Saatcioglu
Keyword(s):  
Androgen Receptor ◽  
Histone Acetylation ◽  
Nuclear Receptor ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Trichostatin A ◽  
Specific Antigen ◽  
Histone Deacetylation ◽  
Lncap Cells ◽  
Viral Oncoprotein

Androgens are critical in the development and maintenance of the male reproductive system and important in the progression of prostate cancer. The effects of androgens are mediated by the androgen receptor (AR), which is a ligand-modulated transcription factor that belongs to the nuclear receptor superfamily. We and others have previously shown that CREB-binding protein (CBP) can function as a coactivator for AR. Similar to some other nuclear receptor coactivators and/or the proteins that they interact with, CBP has histone acetyl transferase (HAT) activity that is thought to contribute to transcriptional activation by nuclear receptors. We have therefore assessed whether an increase in the histone acetylation status in the cell can influence AR transcriptional activity, by using the histone deacetylase (HDAC) inhibitors (HDACIs) trichostatin A (TSA), sodium butyrate (Na-But) and depsipeptide (FR901228). We found that inhibition of HDAC activity significantly increased the ability of endogenous AR in LNCaP cells, or ectopically expressed AR in HeLa cells, to activate transcription from AR-dependent reporter constructs. In addition, HDACIs increased the androgen-dependent activation of the prostate-specific antigen (PSA) gene in LNCaP cells, an increase that was not due to an increase in nuclear AR protein levels. Moreover, the viral oncoprotein E1A that inhibits CBP HAT activity fully repressed the ability of HDACIs to stimulate AR-mediated transcription, indicating that CBP is involved in this process. Deletional mutagenesis of AR indicated that whereas the AF-2 domain in the C-terminus is dispensable, the AF-1 domain in the N-terminus is required for augmentation of AR action by HDACIs, an observation which is in concordance with the reduced ability of CBP to activate AR N-terminal deletion mutants. Furthermore, HDACI treatment rescued the deficiency in the transactivation potential of AF-2 mutants. Taken together, our findings suggest that a change in the level of histone acetylation of target genes is an important determinant of AR action, possibly mediated by CBP.

scholarly journals Differential modulation of androgen receptor transcriptional activity by the nuclear receptor co-repressor (N-CoR)

2004 ◽  
Vol 379 (3) ◽  
pp. 731-738 ◽  
Author(s):  
Cor A. BERREVOETS ◽  
Arzu UMAR ◽  
Jan TRAPMAN ◽  
Albert O. BRINKMANN
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Conformational Change ◽  
Nuclear Receptor ◽  
Cyproterone Acetate ◽  
Transcriptional Activity ◽  
Differential Modulation ◽  
Partial Agonists ◽  
Receptor Action

Antiandrogens are widely used agents in the treatment of prostate cancer, as inhibitors of AR (androgen receptor) action. Although the precise mechanism of antiandrogen action is not yet elucidated, recent studies indicate the involvement of nuclear receptor co-repressors. In the present study, the regulation of AR transcriptional activity by N-CoR (nuclear receptor co-repressor), in the presence of different ligands, has been investigated. Increasing levels of N-CoR differentially affected the transcriptional activity of AR occupied with either agonistic or antagonistic ligands. Small amounts of co-transfected N-CoR repressed CPA (cyproterone acetate)- and mifepristone (RU486)-mediated AR activity, but did not affect agonist (R1881)-induced AR activity. Larger amounts of co-transfected N-CoR repressed AR activity for all ligands, and converted the partial agonists CPA and RU486 into strong AR antagonists. In the presence of the agonist R1881, co-expression of the p160 co-activator TIF2 (transcriptional intermediary factor 2) relieved N-CoR repression up to control levels. However, in the presence of RU486 and CPA, TIF2 did not functionally compete with N-CoR, suggesting that antagonist-bound AR has a preference for N-CoR. The AR mutation T877A (Thr877→Ala), which is frequently found in prostate cancer and affects the ligand-induced conformational change of the AR, considerably reduced the repressive action of N-CoR. The agonistic activities of CPA- and hydroxyflutamide-occupied T877A-AR were hardly affected by N-CoR, whereas TIF2 strongly enhanced their activities. These results indicate that lack of N-CoR action allows these antiandrogens to act as strong agonists on the mutant AR.

Prolonged influence of a neonatal cyproterone acetate treatment on renal androgen binding in mice

1988 ◽  
Vol 119 (2) ◽  
pp. 263-268
Author(s):  
G. Veyssiére ◽  
Ch. Gallon ◽  
M. Berger ◽  
Ch. Jean-Faucher ◽  
M. de Turckheim ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Cyproterone Acetate ◽  
Single Injection ◽  
Adult Males ◽  
Male Mice ◽  
Testosterone Levels ◽  
Low Levels ◽  
Androgen Binding

Abstract. To determine whether neonatal endogenous androgens influence adult renal androgen binding, newborn male mice were injected from 1 to 10 days of age with cyproterone acetate and newborn females with testosterone from 1 to 10 days and from 20 to 40 days of age. In controls, at adulthood, the total cellular androgen receptor content was significantly higher in males (1700 200 receptors per cell) than in females (1060 ± 50) and, as expected, the nuclear receptor content was 12-fold higher in males. While the total number of receptors (1650 ± 220 per cell) was unchanged in adult males neonatally treated with cyproterone acetate, their distribution between cytosol and nucleus was similar to that in control females despite normal circulating and renal testosterone levels. The nuclear receptors represented 50, 7 and 11% of the total receptors in control males, control females and cyproterone acetate-treated males, respectively. The very low levels of nuclear receptors present in the kidney of cyproterone acetate-treated males probably explain the decreased sensitivity of this organ to testosterone. The nuclear receptor accumulation measured in adult animals after a single injection of testosterone did not seem to be affected by neonatal hormonal manipulations.

Nuclear receptor atlas of female mouse liver parenchymal, endothelial, and Kupffer cells

2013 ◽  
Vol 45 (7) ◽  
pp. 268-275 ◽  
Author(s):  
Zhaosha Li ◽  
J. Kar Kruijt ◽  
Ronald J. van der Sluis ◽  
Theo J. C. Van Berkel ◽  
Menno Hoekstra
Keyword(s):  
Expression Pattern ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Kupffer Cells ◽  
Virgin Female ◽  
Orphan Receptor ◽  
Orphan Nuclear Receptors ◽  
Liver Parenchymal ◽  
Hepatic Expression ◽  
Parenchymal Cells

The liver consists of different cell types that together synchronize crucial roles in liver homeostasis. Since nuclear receptors constitute an important class of drug targets that are involved in a wide variety of physiological processes, we have composed the hepatic cell type-specific expression profile of nuclear receptors to uncover the pharmacological potential of liver-enriched nuclear receptors. Parenchymal liver cells (hepatocytes) and liver endothelial and Kupffer cells were isolated from virgin female C57BL/6 wild-type mice using collagenase perfusion and counterflow centrifugal elutriation. The hepatic expression pattern of 49 nuclear receptors was generated by real-time quantitative PCR using the NUclear Receptor Signaling Atlas (NURSA) program resources. Thirty-six nuclear receptors were expressed in total liver. FXR-α, EAR2, LXR-α, HNF4-α, and CAR were the most abundantly expressed nuclear receptors in liver parenchymal cells. In contrast, NUR77, COUP-TFII, LXR-α/β, FXR-α, and EAR2 were the most highly expressed nuclear receptors in endothelial and Kupffer cells. Interestingly, members of orphan receptor COUP-TF family showed a distinct expression pattern. EAR2 was highly and exclusively expressed in parenchymal cells, while COUP-TFII was moderately and exclusively expressed in endothelial and Kupffer cells. Of interest, the orphan receptor TR4 showed a similar expression pattern as the established lipid sensor PPAR-γ. In conclusion, our study provides the most complete quantitative assessment of the nuclear receptor distribution in liver reported to date. Our gene expression catalog suggests that orphan nuclear receptors such as COUP-TFII, EAR2, and TR4 may be of significant importance as novel targets for pharmaceutical interventions in liver.

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