scholarly journals Target Gene-Specific Regulation of Androgen Receptor Activity by p42/p44 Mitogen-Activated Protein Kinase

2008 ◽  
Vol 22 (11) ◽  
pp. 2420-2432 ◽  
Author(s):  
Irina U. Agoulnik ◽  
William E. Bingman ◽  
Manjula Nakka ◽  
Wei Li ◽  
Qianben Wang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Target Gene ◽  
Target Genes ◽  
Histone H3 ◽  
Specific Cell ◽  
Mapk Activity ◽  
Long Term Treatment ◽  
Histone H3 Acetylation ◽  
H3 Acetylation

Abstract Evidence that the androgen receptor (AR) is not only important in androgen-dependent prostate cancer, but also continues to play a role in tumors that become resistant to androgen deprivation therapies, highlights the need to find alternate means to block AR activity. AR, a hormone-activated transcription factor, and its coactivators are phosphoproteins. Thus, we sought to determine whether inhibition of specific cell signaling pathways would reduce AR function. We found that short-term inhibition of p42/p44 MAPK activity either by a MAPK kinase inhibitor, U0126, or by depletion of kinase with small interfering RNA caused target gene-specific reductions in AR activity. AR enhances histone H3 acetylation of target genes that are sensitive to U0126 including prostate-specific antigen and TMPRSS2, but does not increase histone H3 acetylation of the U0126-resistant PMEPA1 gene. Thus, although AR induces transcription of many target genes, the molecular changes induced by AR at the chromatin level are target gene specific. Long-term treatment (24–48 h) with U0126 causes a G1 cell cycle arrest and reduces AR expression both through a decrease in AR mRNA and a reduction in AR protein stability. Thus, treatments that reduce p42/p44 MAPK activity in prostate cancer have the potential to reduce AR activity through a reduction in expression levels as well as by target gene-selective inhibition of AR function.

scholarly journals Isoform specific activities of androgen receptor and its splice variants in prostate cancer cells

Endocrinology ◽  
2020 ◽  
Author(s):  
Harika Nagandla ◽  
Matthew J Robertson ◽  
Vasanta Putluri ◽  
Nagireddy Putluri ◽  
Cristian Coarfa ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Target Gene ◽  
Target Genes ◽  
Splice Variants ◽  
Clinical Samples ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Specific Activities ◽  
Lncap Prostate Cancer Cell

Abstract Androgen receptor (AR) signaling continues to drive castration resistant prostate cancer (CRPC) in spite of androgen deprivation therapy (ADT). Constitutively active shorter variants of AR, lacking the ligand binding domain, are frequently expressed in CRPC and have emerged as a potential mechanism for prostate cancer to escape ADT. ARv7 and AR v567es are two of the most commonly detected variants of AR in clinical samples of advanced, metastatic prostate cancer. It is not clear if variants of AR merely act as weaker substitutes for AR or can mediate unique isoform specific activities different from AR. In this study, we employed LNCaP prostate cancer cell lines with inducible expression of ARv7 or AR v567es to delineate similarities and differences in transcriptomics, metabolomics and lipidomics resulting from the activation of AR, ARv7 or AR v567es. While the majority of target genes were similarly regulated by the action of all three isoforms, we found a clear difference in transcriptomic activities of AR versus the variants, and a few differences between ARv7 and AR v567es. Some of the target gene regulation by AR isoforms was similar in the VCaP background as well. Differences in downstream activities of AR isoforms were also evident from comparison of the metabolome and lipidome in an LNCaP model. Overall our study implies that shorter variants of AR are capable of mediating unique downstream activities different from AR and some of these are isoform specific.

scholarly journals 1α,25-Dihydroxyvitamin D3 Inhibits Growth of VCaP Prostate Cancer Cells Despite Inducing the Growth-Promoting TMPRSS2:ERG Gene Fusion

Endocrinology ◽  
2010 ◽  
Vol 151 (4) ◽  
pp. 1409-1417 ◽  
Author(s):  
Michele N. Washington ◽  
Nancy L. Weigel
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Cells ◽  
Target Gene ◽  
Target Genes ◽  
Fusion Gene ◽  
Critical Factor ◽  
Synthetic Analog ◽  
Prostate Cancer Cells ◽  
Dihydroxyvitamin D3

Vitamin D receptor (VDR) agonists have been shown to reduce the growth of several prostate cancer cell lines. However, the effects of VDR activation have not been examined in the presence of the recently identified androgen-regulated TMPRSS2:ERG gene fusions, which occur in a high percentage of prostate cancers and play a role in growth and invasiveness. In a previous microarray study, we found that VDR activation induces TMPRSS2 expression in LNCaP prostate cancer cells. Here we show that the natural VDR agonist 1α,25-dihydroxyvitamin D3 and its synthetic analog EB1089 increase expression of TMPRSS2:ERG mRNA in VCaP prostate cancer cells; this results in increased ETS-related gene (ERG) protein expression and ERG activity as demonstrated by an increase in the ERG target gene CACNA1D. In VCaP cells, we were not able to prevent EB1089-mediated TMPRSS2:ERG induction with an androgen receptor antagonist, Casodex, although in LNCaP cells, as reported for some other common androgen receptor and VDR target genes, Casodex reduces EB1089-mediated induction of TMPRSS2. However, despite inducing the fusion gene, VDR agonists reduce VCaP cell growth and expression of the ERG target gene c-Myc, a critical factor in VDR-mediated growth inhibition. Thus, the beneficial effects of VDR agonist treatment override some of the negative effects of ERG induction, although others remain to be tested.

scholarly journals Arabidopsis SUMO E3 Ligase SIZ1 Interacts with HDA6 and Negatively Regulates HDA6 Function during Flowering

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3001
Author(s):  
Sujuan Gao ◽  
Xueqin Zeng ◽  
Jianhao Wang ◽  
Yingchao Xu ◽  
Chunwei Yu ◽  
...  
Keyword(s):  
Target Genes ◽  
Environmental Changes ◽  
Histone H3 ◽  
E3 Ligase ◽  
Histone Deacetylase 6 ◽  
Histone H3 Acetylation ◽  
Sumo E3 Ligase ◽  
H3 Acetylation

The changes in histone acetylation mediated by histone deacetylases (HDAC) play a crucial role in plant development and response to environmental changes. Mammalian HDACs are regulated by post-translational modifications (PTM), such as phosphorylation, acetylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification (SUMOylation), which affect enzymatic activity and transcriptional repression. Whether PTMs of plant HDACs alter their functions are largely unknown. In this study, we demonstrated that the Arabidopsis SUMO E3 ligase SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SIZ1) interacts with HISTONE DEACETYLASE 6 (HDA6) both in vitro and in vivo. Biochemical analyses indicated that HDA6 is not modified by SUMO1. Overexpression of HDA6 in siz1-3 background results in a decreased level of histone H3 acetylation, indicating that the activity of HDA6 is increased in siz1-3 plants. Chromatin immunoprecipitation (ChIP) assays showed that SIZ1 represses HDA6 binding to its target genes FLOWERING LOCUS C (FLC) and MADS AFFECTING FLOWERING 4 (MAF4), resulting in the upregulation of FLC and MAF4 by increasing the level of histone H3 acetylation. Together, these findings indicate that the Arabidopsis SUMO E3 ligase SIZ1 interacts with HDA6 and negatively regulates HDA6 function.

scholarly journals A novel P300 inhibitor reverses DUX4-mediated global histone H3 hyperacetylation, target gene expression, and cell death

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw7781 ◽  
Author(s):  
Darko Bosnakovski ◽  
Meiricris T. da Silva ◽  
Sithara T. Sunny ◽  
Elizabeth T. Ener ◽  
Erik A. Toso ◽  
...  
Keyword(s):  
Target Genes ◽  
Histone H3 ◽  
Facioscapulohumeral Muscular Dystrophy ◽  
C Terminus ◽  
Histone H3 Acetylation ◽  
Global Increase ◽  
Genome Activation ◽  
H3 Acetylation ◽  
Zygotic Genome

Facioscapulohumeral muscular dystrophy (FSHD) results from mutations causing overexpression of the transcription factor, DUX4, which interacts with the histone acetyltransferases, EP300 and CBP. We describe the activity of a new spirocyclic EP300/CBP inhibitor, iP300w, which inhibits the cytotoxicity of the DUX4 protein and reverses the overexpression of most DUX4 target genes, in engineered cell lines and FSHD myoblasts, as well as in an FSHD animal model. In evaluating the effect of iP300w on global histone H3 acetylation, we discovered that DUX4 overexpression leads to a dramatic global increase in the total amount of acetylated histone H3. This unexpected effect requires the C-terminus of DUX4, is conserved with mouse Dux, and may facilitate zygotic genome activation. This global increase in histone H3 acetylation is reversed by iP300w, highlighting the central role of EP300 and CBP in the transcriptional mechanism underlying DUX4 cytotoxicity and the translational potential of blocking this interaction.

scholarly journals Chromatin-directed proteomics-identified network of endogenous androgen receptor in prostate cancer cells

Oncogene ◽  
2021 ◽  
Author(s):  
Kaisa-Mari Launonen ◽  
Ville Paakinaho ◽  
Gianluca Sigismondo ◽  
Marjo Malinen ◽  
Reijo Sironen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Target Genes ◽  
Epithelial Mesenchymal Transition ◽  
Protein A ◽  
Chorioallantoic Membrane ◽  
Chromatin Accessibility ◽  
Castration Resistant Prostate Cancer ◽  
Novel Therapy ◽  
Mesenchymal Transition

AbstractTreatment of prostate cancer confronts resistance to androgen receptor (AR)-targeted therapies. AR-associated coregulators and chromatin proteins hold a great potential for novel therapy targets. Here, we employed a powerful chromatin-directed proteomics approach termed ChIP-SICAP to uncover the composition of chromatin protein network, the chromatome, around endogenous AR in castration resistant prostate cancer (CRPC) cells. In addition to several expected AR coregulators, the chromatome contained many nuclear proteins not previously associated with the AR. In the context of androgen signaling in CRPC cells, we further investigated the role of a known AR-associated protein, a chromatin remodeler SMARCA4 and that of SIM2, a transcription factor without a previous association with AR. To understand their role in chromatin accessibility and AR target gene expression, we integrated data from ChIP-seq, RNA-seq, ATAC-seq and functional experiments. Despite the wide co-occurrence of SMARCA4 and AR on chromatin, depletion of SMARCA4 influenced chromatin accessibility and expression of a restricted set of AR target genes, especially those involved in cell morphogenetic changes in epithelial-mesenchymal transition. The depletion also inhibited the CRPC cell growth, validating SMARCA4’s functional role in CRPC cells. Although silencing of SIM2 reduced chromatin accessibility similarly, it affected the expression of a much larger group of androgen-regulated genes, including those involved in cellular responses to external stimuli and steroid hormone stimulus. The silencing also reduced proliferation of CRPC cells and tumor size in chick embryo chorioallantoic membrane assay, further emphasizing the importance of SIM2 in CRPC cells and pointing to the functional relevance of this potential prostate cancer biomarker in CRPC cells. Overall, the chromatome of AR identified in this work is an important resource for the field focusing on this important drug target.

Androgen receptor: acting in the three-dimensional chromatin landscape of prostate cancer cells

2011 ◽  
Vol 5 (1) ◽  
Author(s):  
Harri Makkonen ◽  
Jorma J. Palvimo
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Cells ◽  
Binding Sites ◽  
Target Genes ◽  
Three Dimensional ◽  
Regulatory Elements ◽  
Gene Promoters ◽  
Loop Formation ◽  
Prostate Cancer Cells

AbstractAndrogen receptor (AR) acts as a hormone-controlled transcription factor that conveys the messages of both natural and synthetic androgens to the level of genes and gene programs. Defective AR signaling leads to a wide array of androgen insensitivity disorders, and deregulated AR function, in particular overexpression of AR, is involved in the growth and progression of prostate cancer. Classic models of AR action view AR-binding sites as upstream regulatory elements in gene promoters or their proximity. However, recent wider genomic screens indicate that AR target genes are commonly activated through very distal chromatin-binding sites. This highlights the importance of long-range chromatin regulation of transcription by the AR, shifting the focus from the linear gene models to three-dimensional models of AR target genes and gene programs. The capability of AR to regulate promoters from long distances in the chromatin is particularly important when evaluating the role of AR in the regulation of genes in malignant prostate cells that frequently show striking genomic aberrations, especially gene fusions. Therefore, in addition to the mechanisms of DNA loop formation between the enhancer bound ARs and the transcription apparatus at the target core promoter, the mechanisms insulating distally bound ARs from promiscuously making contacts and activating other than their normal target gene promoters are critical for proper physiological regulation and thus currently under intense investigation. This review discusses the current knowledge about the AR action in the context of gene aberrations and the three-dimensional chromatin landscape of prostate cancer cells.

TM4SF1 , a novel primary androgen receptor target gene over-expressed in human prostate cancer and involved in cell migration

The Prostate ◽  
2011 ◽  
Vol 71 (11) ◽  
pp. 1239-1250 ◽  
Author(s):  
Nathalie Allioli ◽  
Séverine Vincent ◽  
Virginie Vlaeminck-Guillem ◽  
Myriam Decaussin-Petrucci ◽  
Florence Ragage ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Migration ◽  
Androgen Receptor ◽  
Target Gene ◽  
Human Prostate ◽  
Human Prostate Cancer ◽  
Androgen Receptor Target Gene
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