scholarly journals The androgen receptor regulates a druggable translational regulon in advanced prostate cancer

2019 ◽  
Vol 11 (503) ◽  
pp. eaaw4993 ◽  
Author(s):  
Yuzhen Liu ◽  
Jessie L. Horn ◽  
Kalyan Banda ◽  
Asha Z. Goodman ◽  
Yiting Lim ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Translation Initiation ◽  
Transcriptional Control ◽  
Regulatory Element ◽  
Negative Regulator ◽  
Mrna Transcription ◽  
Posttranscriptional Gene Regulation ◽  
Prostate Cancer Development

The androgen receptor (AR) is a driver of cellular differentiation and prostate cancer development. An extensive body of work has linked these normal and aberrant cellular processes to mRNA transcription; however, the extent to which AR regulates posttranscriptional gene regulation remains unknown. Here, we demonstrate that AR uses the translation machinery to shape the cellular proteome. We show that AR is a negative regulator of protein synthesis and identify an unexpected relationship between AR and the process of translation initiation in vivo. This is mediated through direct transcriptional control of the translation inhibitor 4EBP1. We demonstrate that lowering AR abundance increases the assembly of the eIF4F translation initiation complex, which drives enhanced tumor cell proliferation. Furthermore, we uncover a network of pro-proliferation mRNAs characterized by a guanine-rich cis-regulatory element that is particularly sensitive to eIF4F hyperactivity. Using both genetic and pharmacologic methods, we demonstrate that dissociation of the eIF4F complex reverses the proliferation program, resulting in decreased tumor growth and improved survival in preclinical models. Our findings reveal a druggable nexus that functionally links the processes of mRNA transcription and translation initiation in an emerging class of lethal AR-deficient prostate cancer.

scholarly journals Characterisation of the androgen regulation of glycine N-methyltransferase in prostate cancer cells

2013 ◽  
Vol 51 (3) ◽  
pp. 301-312 ◽  
Author(s):  
Silvia Ottaviani ◽  
Greg N Brooke ◽  
Ciara O'Hanlon-Brown ◽  
Jonathan Waxman ◽  
Simak Ali ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Regulatory Element ◽  
Prostate Cancer Cells ◽  
Protein Levels ◽  
Prostate Cancer Development ◽  
Androgen Regulation

The development and growth of prostate cancer is dependent on androgens; thus, the identification of androgen-regulated genes in prostate cancer cells is vital for defining the mechanisms of prostate cancer development and progression and developing new markers and targets for prostate cancer treatment. GlycineN-methyltransferase (GNMT) is aS-adenosylmethionine-dependent methyltransferase that has been recently identified as a novel androgen-regulated gene in prostate cancer cells. Although the importance of this protein in prostate cancer progression has been extensively addressed, little is known about the mechanism of its androgen regulation. Here, we show that GNMT expression is stimulated by androgen in androgen receptor (AR) expressing cells and that the stimulation occurs at the mRNA and protein levels. We have identified an androgen response element within the first exon of theGNMTgene and demonstrated that AR binds to this elementin vitroandin vivo. Together, these studies identify GNMT as a direct transcriptional target of the AR. As this is an evolutionarily conserved regulatory element, this highlights androgen regulation as an important feature of GNMT regulation.

scholarly journals Preclinical studies using cisplatin/carboplatin to restore the Enzalutamide sensitivity via degrading the androgen receptor splicing variant 7 (ARv7) to further suppress Enzalutamide resistant prostate cancer

2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Fu-Ju Chou ◽  
ChangYi Lin ◽  
Hao Tian ◽  
WanYing Lin ◽  
Bosen You ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Rna Splicing ◽  
Preclinical Studies ◽  
Castration Resistant Prostate Cancer ◽  
Splicing Variant ◽  
Castration Resistant ◽  
Lncrna Malat1 ◽  
Near Future

Abstract The FDA-approved anti-androgen Enzalutamide (Enz) has been used successfully as the last line therapy to extend castration-resistant prostate cancer (CRPC) patients’ survival by an extra 4.8 months. However, CRPC patients eventually develop Enz-resistance that may involve the induction of the androgen receptor (AR) splicing variant ARv7. Here we found that Cisplatin (Cis) or Carboplatin, currently used in chemotherapy/radiation therapy to suppress tumor progression, could restore the Enz sensitivity in multiple Enz-resistant (EnzR) CRPC cells via directly degrading/suppressing the ARv7. Combining Cis or Carboplatin with Enz therapy can also delay the development of Enz-resistance in CRPC C4-2 cells. Mechanism dissection found that Cis or Carboplatin might decrease the ARv7 expression via multiple mechanisms including targeting the lncRNA-Malat1/SF2 RNA splicing complex and increasing ARv7 degradation via altering ubiquitination. Preclinical studies using in vivo mouse model with implanted EnzR1-C4-2 cells also demonstrated that Cis plus Enz therapy resulted in better suppression of EnzR CRPC progression than Enz treatment alone. These results not only unveil the previously unrecognized Cis mechanism to degrade ARv7 via targeting the Malat1/SF2 complex and ubiquitination signals, it may also provide a novel and ready therapy to further suppress the EnzR CRPC progression in the near future.

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 Disrupting Androgen Receptor Functionality with Xanthones from the Mangosteen (Garcinia mangostana) Fruit

Proceedings ◽  
2020 ◽  
Vol 40 (1) ◽  
pp. 50
Author(s):  
Jeremy J. Johnson
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Cells ◽  
Cellular Proliferation ◽  
Xenograft Model ◽  
Pharmacokinetic Studies ◽  
Garcinia Mangostana ◽  
Optimal Dosing ◽  
Anti Cancer

The Southeast Asian mangosteen (Garcinia mangostana) contains a class of phytochemicals known as xanthones that possess extensive biological activity. Applications of xanthones, including the most prominent, alpha-mangostin, have been shown to possess anti-cancer, anti-oxidant, and anti-proliferation properties. To confirm the anti-cancer activity of xanthones we have evaluated 9 xanthones for decreasing cellular proliferation of cancer cells. These xanthones include alpha-mangostin, gartanin, 9-hydroxycalabaxanthone, garcinone C, garcinone D, and others. Using this approach, we have focused on understanding the ability of xanthones to disrupt androgen receptor in prostate cancer cells with a combination of cell free and cell-based assays. In addition, we have performed pharmacokinetic studies in mice with alpha-mangostin to characterize the optimal dosing strategy. Taken together, we have identified individual xanthones as capable of disrupting kinases, including CDK4, using cell free biochemical models and cell-based animal models. These results have been further validated in an in vivo xenograft model. Taken together, we have begun to describe the anti-cancer potential of xanthones for prostate cancer.

scholarly journals Long-Range Transcriptional Control of theIl2Gene by an Intergenic Enhancer

2015 ◽  
Vol 35 (22) ◽  
pp. 3880-3891 ◽  
Author(s):  
Parul Mehra ◽  
Andrew D. Wells
Keyword(s):  
Autoimmune Disease ◽  
Long Range ◽  
Transcriptional Control ◽  
Regulatory Element ◽  
Interleukin 2 ◽  
Regulatory Region ◽  
Dependent Manner ◽  
Regulatory Architecture

Interleukin-2 (IL-2) is a potent cytokine with roles in both immunity and tolerance. Genetic studies in humans and mice demonstrate a role forIl2in autoimmune disease susceptibility, and for decades the proximalIl2upstream regulatory region has served as a paradigm of tissue-specific, inducible gene regulation. In this study, we have identified a novel long-range enhancer of theIl2gene located 83 kb upstream of the transcription start site. This element can potently enhanceIl2transcription in recombinant reporter assaysin vitro, and the native region undergoes chromatin remodeling, transcribes a bidirectional enhancer RNA, and loops to physically interact with theIl2genein vivoin a CD28-dependent manner in CD4+T cells. Thiscisregulatory element is evolutionarily conserved and is situated near a human single-nucleotide polymorphism (SNP) associated with multiple autoimmune disorders. These results indicate that the regulatory architecture of theIl2locus is more complex than previously appreciated and suggest a novel molecular basis for the genetic association ofIl2polymorphism with autoimmune disease.

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