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Lumahan LEV, Arif M, Whitener AE, Yi P. Regulating Androgen Receptor Function in Prostate Cancer: Exploring the Diversity of Post-Translational Modifications. Cells 2024; 13:191. [PMID: 38275816 PMCID: PMC10814774 DOI: 10.3390/cells13020191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/27/2024] Open
Abstract
Androgen receptor (AR) transcriptional activity significantly influences prostate cancer (PCa) progression. In addition to ligand stimulation, AR transcriptional activity is also influenced by a variety of post-translational modifications (PTMs). A number of oncogenes and tumor suppressors have been observed leveraging PTMs to influence AR activity. Subjectively targeting these post-translational modifiers based on their impact on PCa cell proliferation is a rapidly developing area of research. This review elucidates the modifiers, contextualizes the effects of these PTMs on AR activity, and connects these cellular interactions to the progression of PCa.
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Affiliation(s)
- Lance Edward V. Lumahan
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77204, USA
| | - Mazia Arif
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77205, USA
| | - Amy E. Whitener
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77205, USA
| | - Ping Yi
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77205, USA
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2
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Piol D, Tosatto L, Zuccaro E, Anderson EN, Falconieri A, Polanco MJ, Marchioretti C, Lia F, White J, Bregolin E, Minervini G, Parodi S, Salvatella X, Arrigoni G, Ballabio A, La Spada AR, Tosatto SC, Sambataro F, Medina DL, Pandey UB, Basso M, Pennuto M. Antagonistic effect of cyclin-dependent kinases and a calcium-dependent phosphatase on polyglutamine-expanded androgen receptor toxic gain of function. SCIENCE ADVANCES 2023; 9:eade1694. [PMID: 36608116 PMCID: PMC9821870 DOI: 10.1126/sciadv.ade1694] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Spinal and bulbar muscular atrophy is caused by polyglutamine (polyQ) expansions in androgen receptor (AR), generating gain-of-function toxicity that may involve phosphorylation. Using cellular and animal models, we investigated what kinases and phosphatases target polyQ-expanded AR, whether polyQ expansions modify AR phosphorylation, and how this contributes to neurodegeneration. Mass spectrometry showed that polyQ expansions preserve native phosphorylation and increase phosphorylation at conserved sites controlling AR stability and transactivation. In small-molecule screening, we identified that CDC25/CDK2 signaling could enhance AR phosphorylation, and the calcium-sensitive phosphatase calcineurin had opposite effects. Pharmacologic and genetic manipulation of these kinases and phosphatases modified polyQ-expanded AR function and toxicity in cells, flies, and mice. Ablation of CDK2 reduced AR phosphorylation in the brainstem and restored expression of Myc and other genes involved in DNA damage, senescence, and apoptosis, indicating that the cell cycle-regulated kinase plays more than a bystander role in SBMA-vulnerable postmitotic cells.
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Affiliation(s)
- Diana Piol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Padova Neuroscience Center, Padova, Italy
- Dulbecco Telethon Institute (DTI), Department of Cellular, Computational, and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Laura Tosatto
- Dulbecco Telethon Institute (DTI), Department of Cellular, Computational, and Integrative Biology (CIBIO), University of Trento, Trento, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche (CNR), Trento, Italy
| | - Emanuela Zuccaro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Padova Neuroscience Center, Padova, Italy
| | - Eric N. Anderson
- Division of Child Neurology, Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | | | - Maria J. Polanco
- Dulbecco Telethon Institute (DTI), Department of Cellular, Computational, and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Caterina Marchioretti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Padova Neuroscience Center, Padova, Italy
| | - Federica Lia
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Padova Neuroscience Center, Padova, Italy
| | - Joseph White
- Department of Pathology and Laboratory Medicine, Department of Neurology, Department of Biological Chemistry, and the UCI Institute for Neurotherapeutics, University of California, Irvine, CA 92697, USA
| | - Elisa Bregolin
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Padova Neuroscience Center, Padova, Italy
| | | | - Sara Parodi
- Istituto Italiano di Tecnologia, Genova, Italy
| | - Xavier Salvatella
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- ICREA, Passeig Lluís Companys 23, Barcelona, Spain
| | - Giorgio Arrigoni
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy
- Department of Medical and Translational Science, Federico II University, Naples, Italy
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Albert R. La Spada
- Department of Pathology and Laboratory Medicine, Department of Neurology, Department of Biological Chemistry, and the UCI Institute for Neurotherapeutics, University of California, Irvine, CA 92697, USA
| | - Silvio C. E. Tosatto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche (CNR), Padova, Italy
| | - Fabio Sambataro
- Padova Neuroscience Center, Padova, Italy
- Department of Neuroscience, University of Padova, Padova, Italy
| | - Diego L. Medina
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Udai B. Pandey
- Division of Child Neurology, Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Manuela Basso
- Department of Cellular, Computational, and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Maria Pennuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Padova Neuroscience Center, Padova, Italy
- Dulbecco Telethon Institute (DTI), Department of Cellular, Computational, and Integrative Biology (CIBIO), University of Trento, Trento, Italy
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3
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Guo X, He H, Yu J, Shi S. PKSPS: a novel method for predicting kinase of specific phosphorylation sites based on maximum weighted bipartite matching algorithm and phosphorylation sequence enrichment analysis. Brief Bioinform 2021; 23:6398688. [PMID: 34661630 DOI: 10.1093/bib/bbab436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/10/2021] [Accepted: 09/21/2021] [Indexed: 11/14/2022] Open
Abstract
With the development of biotechnology, a large number of phosphorylation sites have been experimentally confirmed and collected, but only a few of them have kinase annotations. Since experimental methods to detect kinases at specific phosphorylation sites are expensive and accidental, some computational methods have been proposed to predict the kinase of these sites, but most methods only consider single sequence information or single functional network information. In this study, a new method Predicting Kinase of Specific Phosphorylation Sites (PKSPS) is developed to predict kinases of specific phosphorylation sites in human proteins by combining PKSPS-Net with PKSPS-Seq, which considers protein-protein interaction (PPI) network information and sequence information. For PKSPS-Net, kinase-kinase and substrate-substrate similarity are quantified based on the topological similarity of proteins in the PPI network, and maximum weighted bipartite matching algorithm is proposed to predict kinase-substrate relationship. In PKSPS-Seq, phosphorylation sequence enrichment analysis is used to analyze the similarity of local sequences around phosphorylation sites and predict the kinase of specific phosphorylation sites (KSP). PKSPS has been proved to be more effective than the PKSPS-Net or PKSPS-Seq on different sets of kinases. Further comparison results show that the PKSPS method performs better than existing methods. Finally, the case study demonstrates the effectiveness of the PKSPS in predicting kinases of specific phosphorylation sites. The open source code and data of the PKSPS can be obtained from https://github.com/guoxinyunncu/PKSPS.
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Affiliation(s)
- Xinyun Guo
- Department of Mathematics and Numerical Simulation and High-Performance Computing Laboratory, School of Sciences, Nanchang University, Nanchang 330031, China
| | - Huan He
- Department of Mathematics and Numerical Simulation and High-Performance Computing Laboratory, School of Sciences, Nanchang University, Nanchang 330031, China
| | - Jialin Yu
- Department of Mathematics and Numerical Simulation and High-Performance Computing Laboratory, School of Sciences, Nanchang University, Nanchang 330031, China
| | - Shaoping Shi
- Department of Mathematics and Numerical Simulation and High-Performance Computing Laboratory, School of Sciences, Nanchang University, Nanchang 330031, China
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4
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Selective targeting of the androgen receptor-DNA binding domain by the novel antiandrogen SBF-1 and inhibition of the growth of prostate cancer cells. Invest New Drugs 2021; 39:442-457. [PMID: 33411211 DOI: 10.1007/s10637-020-01050-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/10/2020] [Indexed: 10/22/2022]
Abstract
Prostate cancers are reliant on androgens for growth and survival. Clinicians and researchers are looking for potent treatments for the resistant forms of prostate cancer; however, a handful of small molecules used in the treatment of castration-resistant prostate cancer have not shown potent effects owing to the mutations in the AR (Androgen Receptor). We used SBF-1, a well-characterized antitumor agent with potent cytotoxic effects against different kinds of cancers and investigated its effect on human prostate cancer. SBF-1 substantially inhibited the proliferation, induced apoptosis, and caused cell cycle arrest in LNCaP and PC3/AR+ prostate cancer cell lines. SBF-1 inhibited the activation of the IGF-1-PNCA pathway, as demonstrated by decreased expression of IGF-1 (insulin-like growth factor 1), proliferating cell nuclear antigen (PCNA), and its downstream Bcl-2 protein. Using microscale thermophoresis (MST) and isothermal titration calorimetry (ITC) assays, we observed a direct binding of SBF-1 to the AR. SBF-1 binds to the AR-DBD (DNA-binding domain) and blocks the transcription of its target gene. SBF-1 demonstrated a potent antitumor effect in vivo; it inhibited AR signaling and suppressed tumor growth in animals. Our study suggests that SBF-1 is an inhibitor of the AR and might be used in the treatment of prostate cancer.
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5
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Kraemer WJ, Ratamess NA, Hymer WC, Nindl BC, Fragala MS. Growth Hormone(s), Testosterone, Insulin-Like Growth Factors, and Cortisol: Roles and Integration for Cellular Development and Growth With Exercise. Front Endocrinol (Lausanne) 2020; 11:33. [PMID: 32158429 PMCID: PMC7052063 DOI: 10.3389/fendo.2020.00033] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/16/2020] [Indexed: 12/16/2022] Open
Abstract
Hormones are largely responsible for the integrated communication of several physiological systems responsible for modulating cellular growth and development. Although the specific hormonal influence must be considered within the context of the entire endocrine system and its relationship with other physiological systems, three key hormones are considered the "anabolic giants" in cellular growth and repair: testosterone, the growth hormone superfamily, and the insulin-like growth factor (IGF) superfamily. In addition to these anabolic hormones, glucocorticoids, mainly cortisol must also be considered because of their profound opposing influence on human skeletal muscle anabolism in many instances. This review presents emerging research on: (1) Testosterone signaling pathways, responses, and adaptations to resistance training; (2) Growth hormone: presents new complexity with exercise stress; (3) Current perspectives on IGF-I and physiological adaptations and complexity these hormones as related to training; and (4) Glucocorticoid roles in integrated communication for anabolic/catabolic signaling. Specifically, the review describes (1) Testosterone as the primary anabolic hormone, with an anabolic influence largely dictated primarily by genomic and possible non-genomic signaling, satellite cell activation, interaction with other anabolic signaling pathways, upregulation or downregulation of the androgen receptor, and potential roles in co-activators and transcriptional activity; (2) Differential influences of growth hormones depending on the "type" of the hormone being assayed and the magnitude of the physiological stress; (3) The exquisite regulation of IGF-1 by a family of binding proteins (IGFBPs 1-6), which can either stimulate or inhibit biological action depending on binding; and (4) Circadian patterning and newly discovered variants of glucocorticoid isoforms largely dictating glucocorticoid sensitivity and catabolic, muscle sparing, or pathological influence. The downstream integrated anabolic and catabolic mechanisms of these hormones not only affect the ability of skeletal muscle to generate force; they also have implications for pharmaceutical treatments, aging, and prevalent chronic conditions such as metabolic syndrome, insulin resistance, and hypertension. Thus, advances in our understanding of hormones that impact anabolic: catabolic processes have relevance for athletes and the general population, alike.
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Affiliation(s)
- William J. Kraemer
- Department of Human Sciences, The Ohio State University, Columbus, OH, United States
- *Correspondence: William J. Kraemer
| | - Nicholas A. Ratamess
- Department of Health and Exercise Science, The College of New Jersey, Ewing, NJ, United States
| | - Wesley C. Hymer
- Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Bradley C. Nindl
- Department of Sports Medicine, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA, United States
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6
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Schuppe ER, Miles MC, Fuxjager MJ. Evolution of the androgen receptor: Perspectives from human health to dancing birds. Mol Cell Endocrinol 2020; 499:110577. [PMID: 31525432 DOI: 10.1016/j.mce.2019.110577] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/04/2019] [Accepted: 09/09/2019] [Indexed: 12/23/2022]
Abstract
Androgenic hormones orchestrate the development and activation of diverse reproductive phenotypes across vertebrates. Although extensive work investigates how selection for these traits modifies individual elements of this signaling system (e.g., hormone or androgen receptor [AR] levels), we know less about natural variation in the AR sequence across vertebrates. Our knowledge of AR sequence mutations is largely limited to work in human patients or cell-lines, providing a framework to contextualize single mutations at the expense of evolutionary timescale. Here we unite both perspectives in a review that explores the functional significance of AR on a domain-by-domain basis, using existing knowledge to highlight how and why each region might evolve. We then examine AR sequence variation on different timescales by examining sequence variation in clades originating in the Cambrian (vertebrates; >500 mya) and Cretaceous (birds; >65 mya). In each case, we characterize how the receptor has changed over time and discuss which regions are most likely to evolve in response to selection. Overall, domains that are required for androgenic signaling to function (e.g., DNA- and ligand-binding) tend to be conserved. Meanwhile, areas that interface with co-regulatory molecules can exhibit notable variation even between closely related species. We propose that accumulating mutations in regulatory regions is one way that AR structure might act as a substrate for selection to guide the evolution of reproductive traits. By synthesizing literature across disciplines and highlighting the evolutionary potential of specific AR regions, we hope to inspire new avenues of integrative research into endocrine system evolution.
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Affiliation(s)
- Eric R Schuppe
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, 14853, USA
| | - Meredith C Miles
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, 02912, USA
| | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, 02912, USA.
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7
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Wen S, Niu Y, Huang H. Posttranslational regulation of androgen dependent and independent androgen receptor activities in prostate cancer. Asian J Urol 2019; 7:203-218. [PMID: 33024699 PMCID: PMC7525085 DOI: 10.1016/j.ajur.2019.11.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/21/2019] [Accepted: 10/11/2019] [Indexed: 12/12/2022] Open
Abstract
Prostate cancer (PCa) is the most commonly diagnosed cancer among men in western countries. Androgen receptor (AR) signaling plays key roles in the development of PCa. Androgen deprivation therapy (ADT) remains the standard therapy for advanced PCa. In addition to its ligand androgen, accumulating evidence indicates that posttranscriptional modification is another important mechanism to regulate AR activities during the progression of PCa, especially in castration resistant prostate cancer (CRPC). To date, a number of posttranscriptional modifications of AR have been identified, including phosphorylation (e.g. by CDK1), acetylation (e.g. by p300 and recognized by BRD4), methylation (e.g. by EZH2), ubiquitination (e.g. by SPOP), and SUMOylation (e.g. by PIAS1). These modifications are essential for the maintenance of protein stability, nuclear localization and transcriptional activity of AR. This review summarizes posttranslational modifications that influence androgen-dependent and -independent activities of AR, PCa progression and therapy resistance. We further emphasize that in addition to androgen, posttranslational modification is another important way to regulate AR activity, suggesting that targeting AR posttranslational modifications, such as proteolysis targeting chimeras (PROTACs) of AR, represents a potential and promising alternate for effective treatment of CRPC. Potential areas to be investigated in the future in the field of AR posttranslational modifications are also discussed.
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Affiliation(s)
- Simeng Wen
- Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, USA
| | - Yuanjie Niu
- Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin Medical University, Tianjin, China
| | - Haojie Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, USA.,Department of Urology, Mayo Clinic College of Medicine and Science, Rochester, USA.,Mayo Clinic Cancer Center, Mayo Clinic College of Medicine and Science, Rochester, USA
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8
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Polanco MJ, Parodi S, Piol D, Stack C, Chivet M, Contestabile A, Miranda HC, Lievens PMJ, Espinoza S, Jochum T, Rocchi A, Grunseich C, Gainetdinov RR, Cato ACB, Lieberman AP, La Spada AR, Sambataro F, Fischbeck KH, Gozes I, Pennuto M. Adenylyl cyclase activating polypeptide reduces phosphorylation and toxicity of the polyglutamine-expanded androgen receptor in spinobulbar muscular atrophy. Sci Transl Med 2017; 8:370ra181. [PMID: 28003546 DOI: 10.1126/scitranslmed.aaf9526] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 05/02/2016] [Accepted: 12/01/2016] [Indexed: 12/16/2022]
Abstract
Spinobulbar muscular atrophy (SBMA) is an X-linked neuromuscular disease caused by polyglutamine (polyQ) expansion in the androgen receptor (AR) gene. SBMA belongs to the family of polyQ diseases, which are fatal neurodegenerative disorders mainly caused by protein-mediated toxic gain-of-function mechanisms and characterized by deposition of misfolded proteins in the form of aggregates. The neurotoxicity of the polyQ proteins can be modified by phosphorylation at specific sites, thereby providing the rationale for the development of disease-specific treatments. We sought to identify signaling pathways that modulate polyQ-AR phosphorylation for therapy development. We report that cyclin-dependent kinase 2 (CDK2) phosphorylates polyQ-AR specifically at Ser96 Phosphorylation of polyQ-AR by CDK2 increased protein stabilization and toxicity and is negatively regulated by the adenylyl cyclase (AC)/protein kinase A (PKA) signaling pathway. To translate these findings into therapy, we developed an analog of pituitary adenylyl cyclase activating polypeptide (PACAP), a potent activator of the AC/PKA pathway. Chronic intranasal administration of the PACAP analog to knock-in SBMA mice reduced Ser96 phosphorylation, promoted polyQ-AR degradation, and ameliorated disease outcome. These results provide proof of principle that noninvasive therapy based on the use of PACAP analogs is a therapeutic option for SBMA.
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Affiliation(s)
- Maria Josè Polanco
- Dulbecco Telethon Institute, Centre for Integrative Biology, University of Trento, 38123 Trento, Italy.,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Sara Parodi
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy.,Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Diana Piol
- Dulbecco Telethon Institute, Centre for Integrative Biology, University of Trento, 38123 Trento, Italy
| | - Conor Stack
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mathilde Chivet
- Dulbecco Telethon Institute, Centre for Integrative Biology, University of Trento, 38123 Trento, Italy
| | - Andrea Contestabile
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Helen C Miranda
- Departments of Cellular and Molecular Medicine, Pediatrics, and Neurosciences, and Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.,Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Patricia M-J Lievens
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy
| | - Stefano Espinoza
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Tobias Jochum
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, and abcr GmbH, Karlsruhe, Germany
| | - Anna Rocchi
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Christopher Grunseich
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Raul R Gainetdinov
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, 143025 Moscow, Russia
| | - Andrew C B Cato
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Albert R La Spada
- Departments of Cellular and Molecular Medicine, Pediatrics, and Neurosciences, and Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.,Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Fabio Sambataro
- Department of Experimental and Clinical Medical Sciences (DISM), University of Udine, 33100 Udine, Italy
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Illana Gozes
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv 69978, Israel
| | - Maria Pennuto
- Dulbecco Telethon Institute, Centre for Integrative Biology, University of Trento, 38123 Trento, Italy. .,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
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9
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Buttigliero C, Tucci M, Bertaglia V, Vignani F, Bironzo P, Di Maio M, Scagliotti GV. Understanding and overcoming the mechanisms of primary and acquired resistance to abiraterone and enzalutamide in castration resistant prostate cancer. Cancer Treat Rev 2015; 41:884-92. [PMID: 26342718 DOI: 10.1016/j.ctrv.2015.08.002] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/16/2015] [Accepted: 08/24/2015] [Indexed: 02/08/2023]
Abstract
In recent years, in castration resistant prostate cancer (CRPC), several new drugs have been approved that prolong overall survival, including enzalutamide and abiraterone, two new-generation hormonal therapies. Despite the demonstrated benefit of these agents, not all patients with CRPC are responsive to treatment, the gain in median progression-free survival with these therapies compared to standard of care is, rather disappointingly, still less than six months and the appearance of acquired resistance is almost universal. Approximately one third of patients treated with abiraterone and 25% of those treated with enzalutamide show primary resistance to these agents. Even if the mechanisms of resistance to these agents are not fully defined, many hypotheses are emerging, including systemic and intratumoral androgen biosynthesis up-regulation, androgen receptor (AR) gene mutations and amplifications, alteration of pathways involved in cross-talk with AR signaling, glucocorticoid receptor overexpression, neuroendocrine differentiation, immune system deregulation and others. The aim of this paper is to review currently available data about mechanisms of resistance to abiraterone and enzalutamide, and to discuss how these mechanisms could be potentially overcome through novel therapeutic agents.
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Affiliation(s)
- Consuelo Buttigliero
- Department of Oncology, Medical Oncology, University of Turin at San Luigi Hospital, Orbassano, Italy.
| | - Marcello Tucci
- Department of Oncology, Medical Oncology, University of Turin at San Luigi Hospital, Orbassano, Italy
| | - Valentina Bertaglia
- Department of Oncology, Medical Oncology, University of Turin at San Luigi Hospital, Orbassano, Italy
| | - Francesca Vignani
- Department of Oncology, Medical Oncology, University of Turin at San Luigi Hospital, Orbassano, Italy
| | - Paolo Bironzo
- Department of Oncology, Medical Oncology, University of Turin at San Luigi Hospital, Orbassano, Italy
| | - Massimo Di Maio
- Department of Oncology, Medical Oncology, University of Turin at San Luigi Hospital, Orbassano, Italy
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10
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van der Steen T, Tindall DJ, Huang H. Posttranslational modification of the androgen receptor in prostate cancer. Int J Mol Sci 2013; 14:14833-59. [PMID: 23863692 PMCID: PMC3742275 DOI: 10.3390/ijms140714833] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 01/03/2023] Open
Abstract
The androgen receptor (AR) is important in the development of the prostate by regulating transcription, cellular proliferation, and apoptosis. AR undergoes posttranslational modifications that alter its transcription activity, translocation to the nucleus and stability. The posttranslational modifications that regulate these events are of utmost importance to understand the functional role of AR and its activity. The majority of these modifications occur in the activation function-1 (AF1) region of the AR, which contains the transcriptional activation unit 1 (TAU1) and 5 (TAU5). Identification of the modifications that occur to these regions may increase our understanding of AR activation in prostate cancer and the role of AR in the progression from androgen-dependent to castration-resistant prostate cancer (CRPC). Most of the posttranslational modifications identified to date have been determined using the full-length AR in androgen dependent cells. Further investigations into the role of posttranslational modifications in androgen-independent activation of full-length AR and constitutively active splicing variants are warranted, findings from which may provide new therapeutic options for CRPC.
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Affiliation(s)
- Travis van der Steen
- Department of Urology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; E-Mails: (T.V.S.); (D.J.T.)
| | - Donald J. Tindall
- Department of Urology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; E-Mails: (T.V.S.); (D.J.T.)
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Haojie Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-507-284-0020; Fax: +1-507-293-3071
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11
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Abstract
The androgen receptor (AR) has been identified for decades and mediates essential steroid functions. Like most of biological molecules, AR functional activities are modulated by post-translational modifications. This review is focused on the reported activities and significance of AR phosphorylation, with particular emphasis on proline-directed serine/threonine phosphorylation that occurs predominantly on the receptor. The marked enrichment of AR phosphorylation in the most diverse N-terminal domain suggests that targeting AR phosphorylation can be synergistic to antagonizing the C-terminal domain by clinical antiandrogens.
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Affiliation(s)
- Yanfei Gao
- Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School 330 Brookline, MA 02115, USA
| | - Shaoyong Chen
- Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School 330 Brookline, MA 02115, USA
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12
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Ottem EN, Bailey DJ, Jordan CL, Breedlove SM. With a little help from my friends: androgens tap BDNF signaling pathways to alter neural circuits. Neuroscience 2012; 239:124-38. [PMID: 23262234 DOI: 10.1016/j.neuroscience.2012.12.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 12/03/2012] [Accepted: 12/05/2012] [Indexed: 12/20/2022]
Abstract
Gonadal androgens are critical for the development and maintenance of sexually dimorphic regions of the male nervous system, which is critical for male-specific behavior and physiological functioning. In rodents, the motoneurons of the spinal nucleus of the bulbocavernosus (SNB) provide a useful example of a neural system dependent on androgen. Unless rescued by perinatal androgens, the SNB motoneurons will undergo apoptotic cell death. In adulthood, SNB motoneurons remain dependent on androgen, as castration leads to somal atrophy and dendritic retraction. In a second vertebrate model, the zebra finch, androgens are critical for the development of several brain nuclei involved in song production in males. Androgen deprivation during a critical period during postnatal development disrupts song acquisition and dimorphic size-associated nuclei. Mechanisms by which androgens exert masculinizing effects in each model system remain elusive. Recent studies suggest that brain-derived neurotrophic factor (BDNF) may play a role in androgen-dependent masculinization and maintenance of both SNB motoneurons and song nuclei of birds. This review aims to summarize studies demonstrating that BDNF signaling via its tyrosine receptor kinase (TrkB) receptor may work cooperatively with androgens to maintain somal and dendritic morphology of SNB motoneurons. We further describe studies that suggest the cellular origin of BDNF is of particular importance in androgen-dependent regulation of SNB motoneurons. We review evidence that androgens and BDNF may synergistically influence song development and plasticity in bird species. Finally, we provide hypothetical models of mechanisms that may underlie androgen- and BDNF-dependent signaling pathways.
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Affiliation(s)
- E N Ottem
- Department of Biology, Northern Michigan University, Marquette, MI 49855, USA.
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13
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Androgen receptor phosphorylation at serine 515 by Cdk1 predicts biochemical relapse in prostate cancer patients. Br J Cancer 2012; 108:139-48. [PMID: 23321516 PMCID: PMC3553508 DOI: 10.1038/bjc.2012.480] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Background: Prostate cancer cell growth is dependent upon androgen receptor (AR) activation, which is regulated by specific kinases. The aim of the current study is to establish if AR phosphorylation by Cdk1 or ERK1/2 is of prognostic significance. Methods: Scansite 2.0 was utilised to predict which AR sites are phosphorylated by Cdk1 and ERK1/2. Immunohistochemistry for these sites was then performed on 90 hormone-naive prostate cancer specimens. The interaction between Cdk1/ERK1/2 and AR phosphorylation was investigated in vitro using LNCaP cells. Results: Phosphorylation of AR at serine 515 (pARS515) and PSA at diagnosis were independently associated with decreased time to biochemical relapse. Cdk1 and pCdk1161, but not ERK1/2, correlated with pARS515. High expression of pARS515 in patients with a PSA at diagnosis of ⩽20 ng ml−1 was associated with shorter time to biochemical relapse (P=0.019). This translated into a reduction in disease-specific survival (10-year survival, 38.1% vs 100%, P<0.001). In vitro studies demonstrated that treatment with Roscovitine (a Cdk inhibitor) caused a reduction in pCdk1161 expression, pARS515expression and cellular proliferation. Conclusion: In prostate cancer patients with PSA at diagnosis of ⩽20 ng ml−1, phosphorylation of AR at serine 515 by Cdk1 may be an independent prognostic marker.
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14
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Abstract
The androgen receptor (AR) is a key molecule in prostate cancer and Kennedy's disease. Understanding the regulatory mechanisms of this steroid receptor is important in the development of potential therapies for these diseases. One layer of AR regulation is provided by post-translational modifications including phosphorylation, acetylation, sumoylation, ubiquitination and methylation. While these modifications have mostly been studied as individual events, it is becoming clear that these modifications can functionally interact with each other in a signalling pathway. In this review, the effects of all modifications are described with a focus on interplay between them and the functional consequences for the AR.
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Affiliation(s)
- Kelly Coffey
- Solid Tumour Target Discovery Group, The Medical School, Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Framlington Place, Newcastle upon Tyne, Tyne and Wear, UK
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15
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Clinckemalie L, Vanderschueren D, Boonen S, Claessens F. The hinge region in androgen receptor control. Mol Cell Endocrinol 2012; 358:1-8. [PMID: 22406839 DOI: 10.1016/j.mce.2012.02.019] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 01/19/2023]
Abstract
The region between the DNA-binding domain and the ligand-binding domain of nuclear receptors is termed the hinge region. Although this flexible linker is poorly conserved, diverse functions have been ascribed to it. For the androgen receptor (AR), the hinge region and in particular the (629)RKLKKL(634) motif, plays a central role in controlling AR activity, not only because it acts as the main part of the nuclear translocation signal, but also because it regulates the transactivation potential and intranuclear mobility of the receptor. It is also a target site for acetylation, ubiquitylation and methylation. The interplay between these different modifications as well as the phosphorylation at serine 650 will be discussed here. The hinge also has an important function in AR binding to classical versus selective androgen response elements. In addition, the number of coactivators/corepressors that might act via interaction with the hinge region is still growing. The importance of the hinge region is further illustrated by the different somatic mutations described in patients with androgen insensitivity syndrome and prostate cancer. In conclusion, the hinge region serves as an integrator for signals coming from different pathways that provide feedback to the control of AR activity.
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Affiliation(s)
- Liesbeth Clinckemalie
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O&N1, Herestraat 49, 3000 Leuven, Belgium
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16
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Chen S, Gulla S, Cai C, Balk SP. Androgen receptor serine 81 phosphorylation mediates chromatin binding and transcriptional activation. J Biol Chem 2012; 287:8571-83. [PMID: 22275373 DOI: 10.1074/jbc.m111.325290] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Our previous findings indicated that androgen receptor (AR) phosphorylation at serine 81 is stimulated by the mitotic cyclin-dependent kinase 1 (CDK1). In this report, we extended our previous study and confirmed that Ser-81 phosphorylation increases during mitosis, coincident with CDK1 activation. We further showed blocking cell cycle at G(1) or S phase did not disrupt androgen-induced Ser-81 phosphorylation and AR-dependent transcription, consistent with a recent report that AR was phosphorylated at Ser-81 and activated by the transcriptional CDK9. To assess the function of Ser-81 phosphorylation in prostate cancer (PCa) cells expressing endogenous AR, we developed a ligand switch strategy using a ligand-binding domain mutation (W741C) that renders AR responsive to the antagonist bicalutamide. An S81A/W741C double mutant AR stably expressed in PCa cells failed to transactivate the endogenous AR-regulated PSA or TMPRSS2 genes. ChIP showed that the S81A mutation prevented ligand-induced AR recruitment to these genes, and cellular fractionation revealed that the S81A mutation globally abrogated chromatin binding. Conversely, the AR fraction rapidly recruited to chromatin after androgen stimulation was highly enriched for Ser-81 phosphorylation. Finally, inhibition of CDK1 and CDK9 decreased AR Ser-81 phosphorylation, chromatin binding, and transcriptional activity. These findings indicate that Ser-81 phosphorylation by CDK9 stabilizes AR chromatin binding for transcription and suggest that CDK1-mediated Ser-81 phosphorylation during mitosis provides a pool of Ser-81 phosphorylation AR that can be readily recruited to chromatin for gene reactivation and may enhance AR activity in PCa.
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Affiliation(s)
- Shaoyong Chen
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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17
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Abstract
Androgens and the androgen receptor (AR) are indispensable for expression of the male phenotype. The two most important androgens are testosterone and 5α-dihydrotestosterone. The elucidation of the mechanism of androgen action has a long history starting in the 19th century with the classical experiments by Brown-Séquard. In the 1960s the steroid hormone receptor concept was established and the AR was identified as a protein entity with a high affinity and specificity for testosterone and 5α-dihydrotestosterone. In addition, the enzyme 5α-reductase type 2 was discovered and found to catalyze the conversion of testosterone to the more active metabolite 5α-dihydrotestosterone. In the second half of the 1980s, the cDNA cloning of all steroid hormone receptors, including that of the AR, has been another milestone in the whole field of steroid hormone action. Despite two different ligands (testosterone and 5α-dihydrotestosterone), only one AR cDNA has been identified and cloned. The AR (NR3C4) is a ligand-dependent transcription factor and belongs to the family of nuclear hormone receptors which has 48 members in human. The current model for androgen action involves a multistep mechanism. Studies have provided insight into AR association with co-regulators involved in transcription initiation and on intramolecular interactions of the AR protein during activation. Knowledge about androgen action in the normal physiology and in disease states has increased tremendously after cloning of the AR cDNA. Several diseases, such as androgen insensitivity syndrome (AIS), prostate cancer and spinal bulbar muscular atrophy (SBMA), have been shown to be associated with alterations in AR function due to mutations in the AR gene or dysregulation of androgen signalling. A historical overview of androgen action and salient features of AR function in normal and disease states are provided herein.
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Affiliation(s)
- Albert O Brinkmann
- Department of Reproduction and Development, Erasmus MC, Rotterdam, The Netherlands.
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18
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Koochekpour S. Androgen receptor signaling and mutations in prostate cancer. Asian J Androl 2010; 12:639-57. [PMID: 20711217 PMCID: PMC3006239 DOI: 10.1038/aja.2010.89] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/02/2010] [Accepted: 07/14/2010] [Indexed: 12/19/2022] Open
Abstract
Normal and neoplastic growth of the prostate gland are dependent on androgen receptor (AR) expression and function. Androgenic activation of the AR, in association with its coregulatory factors, is the classical pathway that leads to transcriptional activity of AR target genes. Alternatively, cytoplasmic signaling crosstalk of AR by growth factors, neurotrophic peptides, cytokines or nonandrogenic hormones may have important roles in prostate carcinogenesis and in metastatic or androgen-independent (AI) progression of the disease. In addition, cross-modulation by various nuclear transcription factors acting through basal transcriptional machinery could positively or negatively affect the AR or AR target genes expression and activity. Androgen ablation leads to an initial favorable response in a significant number of patients; however, almost invariably patients relapse with an aggressive form of the disease known as castration-resistant or hormone-refractory prostate cancer (PCa). Understanding critical molecular events that lead PCa cells to resist androgen-deprivation therapy is essential in developing successful treatments for hormone-refractory disease. In a significant number of hormone-refractory patients, the AR is overexpressed, mutated or genomically amplified. These genetic alterations maintain an active presence for a highly sensitive AR, which is responsive to androgens, antiandrogens or nonandrogenic hormones and collectively confer a selective growth advantage to PCa cells. This review provides a brief synopsis of the AR structure, AR coregulators, posttranslational modifications of AR, duality of AR function in prostate epithelial and stromal cells, AR-dependent signaling, genetic changes in the form of somatic and germline mutations and their known functional significance in PCa cells and tissues.
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Affiliation(s)
- Shahriar Koochekpour
- Department of Urology and Stanley S. Scott Cancer Center, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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19
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McEwan IJ, McGuinness D, Hay CW, Millar RP, Saunders PTK, Fraser HM. Identification of androgen receptor phosphorylation in the primate ovary in vivo. Reproduction 2010; 140:93-104. [PMID: 20406952 PMCID: PMC2892820 DOI: 10.1530/rep-10-0140] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The androgen receptor (AR) is a member of the nuclear receptor superfamily, and is important for both male and female reproductive health. The receptor is a target for a number of post-translational modifications including phosphorylation, which has been intensively studied in vitro. However, little is known about the phosphorylation status of the receptor in target tissues in vivo. The common marmoset is a useful model for studying human reproductive functions, and comparison of the AR primary sequence from this primate shows high conservation of serines known to be phosphorylated in the human receptor and corresponding flanking amino acids. We have used a panel of phosphospecific antibodies to study AR phosphorylation in the marmoset ovary throughout the follicular phase and after treatment with GNRH antagonist or testosterone propionate. In normal follicular phase ovaries, total AR (both phosphorylated and non-phosphorylated forms) immunopositive staining was observed in several cell types including granulosa cells of developing follicles, theca cells and endothelial cells lining blood vessels. Receptor phosphorylation at serines 81, 308, and 650 was detected primarily in the granulosa cells of developing follicles, surface epithelium, and vessel endothelial cells. Testosterone treatment lead to a modest increase in AR staining in all stages of follicle studied, while GNRH antagonist had no effect. Neither treatment significantly altered the pattern of phosphorylation compared to the control group. These results demonstrate that phosphorylation of the AR occurs, at a subset of serine residues, in a reproductive target tissue in vivo, which appears refractory to hormonal manipulations.
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Affiliation(s)
- Iain J McEwan
- MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK.
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20
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Schütz SV, Cronauer MV, Rinnab L. Inhibition of glycogen synthase kinase-3beta promotes nuclear export of the androgen receptor through a CRM1-dependent mechanism in prostate cancer cell lines. J Cell Biochem 2010; 109:1192-200. [PMID: 20127713 DOI: 10.1002/jcb.22500] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The androgen receptor (AR) is a ligand-dependent transcription factor belonging to the steroid hormone receptor superfamily. Under normal conditions, in the absence of a ligand, the AR is localized to the cytoplasm and is actively transported into the nucleus upon binding of androgens. In advanced prostate cancer (PCa) cell lines, an increased sensitivity to dihydrotestosterone (DHT), enabling the cells to proliferate under sub-physiological levels of androgens, has been associated with increased stability and nuclear localization of the AR. There is experimental evidence that the glycogen synthase kinase-3beta (GSK-3beta), a multifunctional serine/threonine kinase is involved in estrogen and AR stability. As demonstrated in the following study by immunoprecipitation analysis, GSK-3beta binds to the AR forming complexes in the cytoplasm and in the nucleus. Furthermore, inhibition of GSK-3beta activity by pharmacological inhibitors like the maleimide SB216761, the chloromethyl-thienyl-ketone GSK-3 inhibitor VI or the aminopyrazol GSK-3 inhibitor XIII in cells grown in the presence of DHT triggered a rapid nuclear export of endogenous AR as well as of green fluorescent AR-EosFP. The nuclear export of AR following GSK-3beta inhibition could be blocked by leptomycin B suggesting a CRM1-dependent export mechanism. This assumption is supported by the localization of a putative CRM1 binding site at the C-terminus of the AR protein. The results suggest that GSK-3beta is an important element not only in AR stability but also significantly alters nuclear translocation of the AR, thereby modulating the androgenic response of human PCa cells.
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Affiliation(s)
- Stefanie V Schütz
- Institute of General Zoology and Endocrinology, Ulm University, Albert Einstein Allee 11, 89069 Ulm, Germany
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21
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Titus MA, Tan JA, Gregory CW, Ford OH, Subramanian RR, Fu H, Wilson EM, Mohler JL, French FS. 14-3-3{eta} Amplifies Androgen Receptor Actions in Prostate Cancer. Clin Cancer Res 2009; 15:7571-7581. [PMID: 19996220 DOI: 10.1158/1078-0432.ccr-08-1976] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE: Androgen receptor abundance and androgen receptor-regulated gene expression in castration-recurrent prostate cancer are indicative of androgen receptor activation in the absence of testicular androgen. Androgen receptor transactivation of target genes in castration-recurrent prostate cancer occurs in part through mitogen signaling that amplifies the actions of androgen receptor and its coregulators. Herein we report on the role of 14-3-3eta in androgen receptor action. Experimental Design and RESULTS: Androgen receptor and 14-3-3eta colocalized in COS cell nuclei with and without androgen, and 14-3-3eta promoted androgen receptor nuclear localization in the absence of androgen. 14-3-3eta interacted with androgen receptor in cell-free binding and coimmunoprecipitation assays. In the recurrent human prostate cancer cell line, CWR-R1, native endogenous androgen receptor transcriptional activation was stimulated by 14-3-3eta at low dihydrotestosterone concentrations and was increased by epidermal growth factor. Moreover, the dihydrotestosterone- and epidermal growth factor-dependent increase in androgen receptor transactivation was inhibited by a dominant negative 14-3-3eta. In the CWR22 prostate cancer xenograft model, 14-3-3eta expression was increased by androgen, suggesting a feed-forward mechanism that potentiates both 14-3-3eta and androgen receptor actions. 14-3-3eta mRNA and protein decreased following castration of tumor-bearing mice and increased in tumors of castrate mice after treatment with testosterone. CWR22 tumors that recurred 5 months after castration contained 14-3-3eta levels similar to the androgen-stimulated tumors removed before castration. In a human prostate tissue microarray of clinical specimens, 14-3-3eta localized with androgen receptor in nuclei, and the similar amounts expressed in castration-recurrent prostate cancer, androgen-stimulated prostate cancer, and benign prostatic hyperplasia were consistent with androgen receptor activation in recurrent prostate cancer. CONCLUSION: 14-3-3eta enhances androgen- and mitogen-induced androgen receptor transcriptional activity in castration-recurrent prostate cancer. (Clin Cancer Res 2009;15(24):7571-81).
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Affiliation(s)
- Mark A Titus
- Authors' Affiliations: Departments of Pediatrics (Laboratories for Reproductive Biology), Surgery (Division of Urology) and Pathology and Laboratory Medicine, Biochemistry and Biophysics, and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina; Department of Urologic Oncology, Roswell Park Cancer Institute, and Department of Urology, University at Buffalo School of Medicine and Biotechnology, Buffalo, New York; and Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia
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22
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Abstract
Steroid receptors (SRs) are hormone-activated transcription factors important for a wide variety of cellular functions. Post-translational modifications of SRs, including phosphorylation, ubiquitination, acetylation, and sumoylation regulate their expression and function. The remarkable number of phosphorylation sites in these receptors and the wide variety of kinases shown to modulate phosphorylation influence the integration between cell-signaling pathways and SR action. These phosphorylation sites have been identified in all of the functional domains with the majority being located within the amino-terminal portions of the receptors. The regulation of function is receptor specific, site specific, and often dependent on the cellular context. Numerous roles for site-specific phosphorylation have been elucidated including sensitivity of hormone response, DNA binding, expression, stability, subcellular localization, dimerization, and protein-protein interactions that can determine the regulation of specific target genes. This review summarizes the current knowledge regarding receptor site-specific phosphorylation and regulation of function. As functional assays become more sophisticated, it is likely that additional roles for phosphorylation in receptor function will be identified.
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Affiliation(s)
- Robert D Ward
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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23
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Chen S, Kesler CT, Paschal BM, Balk SP. Androgen receptor phosphorylation and activity are regulated by an association with protein phosphatase 1. J Biol Chem 2009; 284:25576-84. [PMID: 19622840 DOI: 10.1074/jbc.m109.043133] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Androgen receptor (AR) is phosphorylated at multiple sites in response to ligand binding, but the functional consequences and mechanisms regulating AR phosphorylation remain to be established. We observed initially that okadaic acid, an inhibitor of the major PPP family serine/threonine phosphatases PP2A and protein phosphatase 1 (PP1), had cell type-dependent effects on AR expression. More specific inhibitors of PP2A (fostriecin) and PP1 (tautomycin and siRNA against the PP1alpha catalytic subunit) demonstrated that PP1 and protein phosphatase 2A had opposite effects on AR protein and transcriptional activity. PP1 inhibition enhanced proteasome-mediated AR degradation, while PP1alpha overexpression increased AR expression and markedly enhanced AR transcriptional activity. Coprecipitation experiments demonstrated an AR-PP1 interaction, while immunofluorescence and nuclear-cytoplasmic fractionation showed androgen-stimulated nuclear translocation of both AR and PP1 in prostate cancer cells. Studies with phosphospecific AR antibodies showed that PP1 inhibition dramatically increased phosphorylation of Ser-650, a site in the AR hinge region shown to mediate nuclear export. Significantly, PP1 inhibition caused a marked decrease in nuclear localization of the wild-type AR, but did not alter total or nuclear levels of a S650A mutant AR. These findings reveal a critical role of PP1 in regulating AR protein stability and nuclear localization through dephosphorylation of Ser-650. Moreover, AR may function as a PP1 regulatory subunit and mediate PP1 recruitment to chromatin, where it can modulate transcription and splicing.
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Affiliation(s)
- Shaoyong Chen
- Cancer Biology Program, Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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24
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Jaworski T. Degradation and beyond: control of androgen receptor activity by the proteasome system. Cell Mol Biol Lett 2009; 11:109-31. [PMID: 16847754 PMCID: PMC6275697 DOI: 10.2478/s11658-006-0011-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Accepted: 01/31/2006] [Indexed: 12/29/2022] Open
Abstract
The androgen receptor (AR) is a transcription factor belonging to the family of nuclear receptors which mediates the action of androgens in the development of urogenital structures. AR expression is regulated post-translationally by the ubiquitin/proteasome system. This regulation involves more complex mechanisms than typical degradation. The ubiquitin/proteasome system may regulate AR via mechanisms that do not engage in receptor turnover. Given the critical role of AR in sexual development, this complex regulation is especially important. Deregulation of AR signalling may be a causal factor in prostate cancer development. AR is the main target in prostate cancer therapies. Due to the critical role of the ubiquitin/proteasome system in AR regulation, current research suggests that targeting AR degradation is a promising approach.
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Affiliation(s)
- Tomasz Jaworski
- Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
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25
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Yuan X, Balk SP. Mechanisms mediating androgen receptor reactivation after castration. Urol Oncol 2009; 27:36-41. [PMID: 19111796 DOI: 10.1016/j.urolonc.2008.03.021] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 03/24/2008] [Accepted: 03/25/2008] [Indexed: 12/30/2022]
Abstract
Androgen deprivation is still the standard systemic therapy for metastatic prostate cancer (PCa), but patients invariably relapse with a more aggressive form of PCa termed hormone refractory, androgen independent, or castration resistant PCa (CRPC). Significantly, the androgen receptor (AR) is expressed at high levels in most cases of CRPC, and these tumors resume their expression of multiple AR-regulated genes, indicating that AR transcriptional activity becomes reactivated at this stage of the disease. The molecular basis for this AR reactivation remains unclear, but possible mechanisms include increased AR expression, AR mutations that enhance activation by weak androgens and AR antagonists, increased expression of transcriptional coactivator proteins, and activation of signal transduction pathways that can enhance AR responses to low levels of androgens. Recent data indicate that CRPC cells may also carry out intracellular synthesis of testosterone and DHT from weak adrenal androgens and may be able to synthesize androgens from cholesterol. These mechanisms that appear to contribute to AR reactivation after castration are further outlined in this review.
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Affiliation(s)
- Xin Yuan
- Cancer Biology Program, Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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26
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Liu P, Li S, Gan L, Kao TP, Huang H. A transcription-independent function of FOXO1 in inhibition of androgen-independent activation of the androgen receptor in prostate cancer cells. Cancer Res 2009; 68:10290-9. [PMID: 19074897 DOI: 10.1158/0008-5472.can-08-2038] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Increasing evidence suggests that aberrant activation of the androgen receptor (AR) plays a pivotal role in the development and progression of androgen depletion-independent prostate cancer (PCa) after androgen deprivation therapy. Here, we show that loss of the PTEN tumor suppressor gene is associated with hyperactivation of the AR in human PCa cell lines. This effect is mediated primarily by its downstream effector FOXO1. In addition to the inhibition of androgenic activation of the AR, forced expression of FOXO1 in PTEN-negative PCa cells also inhibits androgen-independent activation of the AR in a manner independent of FOXO1 transcriptional function. In contrast, silencing of FOXO1 in PTEN-positive cells not only increases the basal activity of the AR in the absence of androgens, it also markedly sensitizes the AR activation by low levels of androgens or nonandrogenic factors such as interleukin-6. FOXO1-mediated inhibition of the AR is partially attenuated by the histone deacetylase (HDAC) inhibitor trichostatin A. Accordingly, FOXO1 interacts with HDAC3 as shown by coimmunoprecipitation assays, and cotransfection of cells with FOXO1 and HDAC3, but not HDAC1 and HDAC2, results in a greater inhibition of AR activity than in cells transfected with FOXO1 or HDAC3 individually. Together, our findings define a novel corepressor function of FOXO1 in inhibition of androgen-independent activation of the AR.
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Affiliation(s)
- Ping Liu
- Department of Laboratory Medicine and Pathology, Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
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27
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Ponguta LA, Gregory CW, French FS, Wilson EM. Site-specific androgen receptor serine phosphorylation linked to epidermal growth factor-dependent growth of castration-recurrent prostate cancer. J Biol Chem 2008; 283:20989-1001. [PMID: 18511414 DOI: 10.1074/jbc.m802392200] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The androgen receptor (AR) is required for prostate cancer development and contributes to tumor progression after remission in response to androgen deprivation therapy. Epidermal growth factor (EGF) increases AR transcriptional activity at low levels of androgen in the CWR-R1 prostate cancer cell line derived from the castration-recurrent CWR22 prostate cancer xenograft. Here we report that knockdown of AR decreases EGF stimulation of prostate cancer cell growth and demonstrate a mechanistic link between EGF and AR signaling. The EGF-induced increase in AR transcriptional activity is dependent on phosphorylation at mitogen-activated protein kinase consensus site Ser-515 in the AR NH(2)-terminal region and at protein kinase C consensus site Ser-578 in the AR DNA binding domain. Phosphorylation at these sites alters the nuclear-cytoplasmic shuttling of AR and AR interaction with the Ku-70/80 regulatory subunits of DNA-dependent protein kinase. Abolishing AR Ser-578 phosphorylation by introducing an S578A mutation eliminates the AR transcriptional response to EGF and increases both AR binding of Ku-70/80 and nuclear retention of AR in association with hyperphosphorylation of AR Ser-515. The results support a model in which AR transcriptional activity increases castration-recurrent prostate cancer cell growth in response to EGF by site-specific serine phosphorylation that regulates nuclear-cytoplasmic shuttling through interactions with the Ku-70/80 regulatory complex.
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Affiliation(s)
- Liliana A Ponguta
- Laboratories for Reproductive Biology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
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28
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Ramesh R, Pearl CA, At-Taras E, Roser JF, Berger T. Ontogeny of androgen and estrogen receptor expression in porcine testis: Effect of reducing testicular estrogen synthesis. Anim Reprod Sci 2007; 102:286-99. [PMID: 17157457 DOI: 10.1016/j.anireprosci.2006.10.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 10/31/2006] [Indexed: 11/17/2022]
Abstract
Reducing endogenous estrogen leads to increased proliferation of porcine Sertoli cells during the first 2 months of life. The resulting increase in porcine Sertoli cell numbers is maintained through puberty. The reduced estrogen appears to be the direct hormonal mediator because essentially no changes are observed in other hormones. However, the mechanism for this effect on Sertoli cell proliferation is unknown. The objective of these studies was to evaluate estrogen receptors alpha and beta (ESR1 and ESR2) in conjunction with androgen receptor (AR) on Sertoli cells and other testicular cell types, as an initial step toward understanding how reduced estrogen leads to increased Sertoli cell numbers. Testis sections from treated animals (aromatase inhibition to decrease endogenous estrogen beginning at 1 week of age) and from littermate controls treated with vehicle were subjected to immunocytochemical labeling for ESR1, ESR2, and AR. Three observers scored Sertoli cells, interstitial cells, peritubular myoid cells, and germ cells for intensity of labeling (0: absent; 1+: weak; 2+: moderate; or 3+: strong labeling). AR in Sertoli cells was readily detected at 1 week of age, was very faint in 2-month vehicle controls, and labeling appeared to increase in 3-month vehicle controls. AR in Sertoli cells, interstitial cells, and apparently germ cells was increased in treated animals at 2 months of age compared with the vehicle controls. This increase was confirmed in western blots. ESR1 and ESR 2 were clearly present in Sertoli cells from 1-week-old animals; ESR in Sertoli cells generally decreased with age with the decrease more apparent for ESR2. ESR1 in Sertoli cells and peritubular myoid cells exhibited some treatment-related effects but reduction of endogenous estrogen did not appear to affect ESR2 in the boar testis. The observed alterations in AR and ESR1 may mediate the increases in Sertoli cell proliferation following inhibition of endogenous estrogen production or may reflect the altered function of the Sertoli cells and peritubular myoid cells.
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Affiliation(s)
- Revathi Ramesh
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
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29
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EstÉbanez-PerpiñÁ E, Jouravel N, Fletterick RJ. Perspectives on designs of antiandrogens for prostate cancer. Expert Opin Drug Discov 2007; 2:1341-55. [DOI: 10.1517/17460441.2.10.1341] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Inoue T, Kobayashi T, Terada N, Shimizu Y, Kamoto T, Ogawa O, Nakamura E. Roles of androgen-dependent and -independent activation of signal transduction pathways for cell proliferation of prostate cancer cells. Expert Rev Endocrinol Metab 2007; 2:689-704. [PMID: 30736131 DOI: 10.1586/17446651.2.5.689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prostate cancer is one of the most frequently diagnosed cancers in the western world and this malignant neoplasm is the second-leading cause of cancer death among men in the USA. In the early 1940s, Huggins and Hodges demonstrated that growth and survival of prostate cancer depends on androgens. The mainstay of treatment for advanced prostate cancer is currently androgen ablation. Over the past few decades, several compounds, such as luteinizing hormone-releasing hormone analogues and anti-androgens, were developed and widely used in clinics. Then, the new treatment strategy, maximum androgen blockade (MAB) was introduced. In fact, MAB improved the prognosis of patients with advanced prostate cancer to some extent; however, most of those patients finally relapse after a period of initial response to this therapy, developing androgen-independent prostate cancer (AIPC). Once patients develop AIPC, effective therapeutic modalities are extremely limited and, therefore, the prognosis of this disease is very poor. It is strongly desirable to explore novel therapeutic concepts for AIPC, based on detailed molecular mechanisms for progression to androgen independency. As for the molecular mechanisms involved in the emergence of AIPC, mutations in the androgen receptor have been examined most extensively. These days, evidence is accumulating that demonstrates activation of signal transduction pathways, such as Src, PI3K and mTOR/S6K, are involved in the acquisition of the androgen-independent cell proliferation of prostate cancer cells. In addition, animal models using transgenic and gene-knockout techniques have confirmed these results. The development of therapies targeting against the signal transduction pathways is critical for the improvement of the prognosis of patients with AIPC. In this article, we review recent understandings on molecular mechanisms of androgen-dependent proliferation of prostate cancer cells, whose aberrant activation is proposed as a critical event for progression to AIPC.
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Affiliation(s)
- Takahiro Inoue
- a Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Takashi Kobayashi
- b Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Naoki Terada
- c Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Yosuke Shimizu
- d Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Toshiyuki Kamoto
- e Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Osamu Ogawa
- f Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Eijiro Nakamura
- g Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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Fuse H, Korenaga S, Sakari M, Hiyama T, Ito T, Kimura K, Kato S. Non-steroidal antiandrogens act as AF-1 agonists under conditions of high androgen-receptor expression. Prostate 2007; 67:630-7. [PMID: 17342748 DOI: 10.1002/pros.20269] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND The mechanism of resistance acquisition to antiandrogens in prostate cancer is not fully understood. Numerous clinical and basic research studies have shown expression of androgen receptors (ARs) increases in hormone-refractory prostate cancer and therefore we explored possible molecular mechanisms by which prostate cancer acquires resistance to antiandrogens under conditions of increased AR expression. METHODS In order to study resistance to antiandrogens at the AR transactivation level we used a human AR (hAR) reporter assay system. In addition, we utilized an hAR deletion mutant to determine the functional domain responsible for the acquisition of resistance. RESULTS Increased hAR protein expression enhanced the sensitivity of AR transactivation to low concentrations of DHT, and also reduced the inhibitory activity of the non-steroidal antiandrogens, hydroxyflutamide, and bicalutamide on DHT-induced AR transactivation. Moreover, these antiandrogens acquired agonistic activity under conditions of high hAR protein expression. Such agonistic activity of antiandrogens was not detected in an hAR deletion mutant (hAR-DeltaA/B) that lacked an A/B domain with AF-1 activity. CONCLUSIONS We found that non-steroidal antiandrogens act as AF-1 agonists under conditions of high AR protein expression. This partial antagonistic property of antiandrogens may be a molecular mechanism by which prostate cancer develops resistance to these drugs.
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Affiliation(s)
- Hiroaki Fuse
- Pharmacological Research Department, ASKA Pharmaceutical Co. Ltd., Takatsu-ku, Kawasaki, Kanagawa, Japan.
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Yang CS, Xin HW, Kelley JB, Spencer A, Brautigan DL, Paschal BM. Ligand binding to the androgen receptor induces conformational changes that regulate phosphatase interactions. Mol Cell Biol 2007; 27:3390-404. [PMID: 17325038 PMCID: PMC1899975 DOI: 10.1128/mcb.02411-06] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2006] [Accepted: 02/14/2007] [Indexed: 11/20/2022] Open
Abstract
We describe a mechanism for protein phosphatase 2A (PP2A) targeting to the androgen receptor (AR) and provide insight into the more general issue of kinase and phosphatase interactions with AR. Simian virus 40 (SV40) small t antigen (ST) binding to N-terminal HEAT repeats in the PP2A A subunit induces structural changes transduced to C-terminal HEAT repeats. This enables the C-terminal HEAT repeats in the PP2A A subunit, including HEAT repeat 13, to discriminate between androgen- and androgen antagonist-induced AR conformations. The PP2A-AR interaction was used to show that an AR mutant in prostate cancer cells (T877A) is activated by multiple ligands without acquiring the same conformation as that induced by androgen. The correlation between androgen binding to AR and increased phosphorylation of the activation function 1 (AF-1) region implies that changes in AR conformation or chaperone composition are causal to kinase access to phosphorylation sites. However, AF-1 phosphorylation sites are kinase accessible prior to androgen binding. This suggests that androgens can enhance the phosphorylation state of AR either by negatively regulating the ability of the ligand-binding domain to bind phosphatases or by inducing an AR conformation that is resistant to phosphatase action. SV40 ST subverts this mechanism by promoting the direct transfer of PP2A onto androgen-bound AR, resulting in multisite dephosphorylation.
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Affiliation(s)
- Chun-Song Yang
- Center for Cell Signaling, University of Virginia, Charlottesville, VA 22908, USA
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Girling JS, Whitaker HC, Mills IG, Neal DE. Pathogenesis of prostate cancer and hormone refractory prostate cancer. Indian J Urol 2007; 23:35-42. [PMID: 19675761 PMCID: PMC2721494 DOI: 10.4103/0970-1591.30265] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Prostate cancer is the second most common malignancy in males and the leading cause of cancer death. Prostate cancer is initially androgen dependent and relies upon the androgen receptor (AR) to mediate the effects of androgens. The AR is also the target for therapy using antiandrogens and LHRH analogues. However, all cancers eventually become androgen independent, often referred to as hormone refractory prostate cancer. The processes involved in this transformation are yet to be fully understood but research in this area has discovered numerous potential mechanisms including AR amplification, over-expression or mutation and alterations in the AR signaling pathway. This review of the recent literature examines the current knowledge and developments in the understanding of the molecular biology of prostate cancer and hormone refractory prostate cancer, summarizing the well characterized pathways involved as well as introducing new concepts that may offer future solutions to this difficult problem.
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Affiliation(s)
- J. S. Girling
- CRUK Uro-oncolgy Group, Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge, CB2 2XZ, UK
| | - H. C. Whitaker
- CRUK Uro-oncolgy Group, Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge, CB2 2XZ, UK
| | - I. G. Mills
- CRUK Uro-oncolgy Group, Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge, CB2 2XZ, UK
| | - D. E. Neal
- CRUK Uro-oncolgy Group, Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge, CB2 2XZ, UK
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34
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Chen S, Xu Y, Yuan X, Bubley GJ, Balk SP. Androgen receptor phosphorylation and stabilization in prostate cancer by cyclin-dependent kinase 1. Proc Natl Acad Sci U S A 2006; 103:15969-74. [PMID: 17043241 PMCID: PMC1635111 DOI: 10.1073/pnas.0604193103] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Androgen receptors (ARs) are phosphorylated at multiple sites in response to ligand binding, but the kinases mediating AR phosphorylation and the importance of these kinases in AR function have not been established. Here we show that cyclin-dependent kinase 1 (Cdk1) mediates AR phosphorylation at Ser-81 and increases AR protein expression, and that Cdk1 inhibitors decrease AR Ser-81 phosphorylation, protein expression, and transcriptional activity in prostate cancer (PCa) cells. The decline in AR protein expression mediated by the Cdk inhibitor roscovitine was prevented by proteosome inhibitors, indicating that Cdk1 stabilizes AR protein, although roscovitine also decreased AR message levels. Analysis of an S81A AR mutant demonstrated that this site is not required for transcriptional activity or Cdk1-mediated AR stabilization in transfected cells. The AR is active and seems to be stabilized by low levels of androgen in "androgen-independent" PCas that relapse subsequent to androgen-deprivation therapy. Significantly, the expression of cyclin B and Cdk1 was increased in these tumors, and treatment with roscovitine abrogated responses to low levels of androgen in the androgen-independent C4-2 PCa cell line. Taken together, these findings identify Cdk1 as a Ser-81 kinase and indicate that Cdk1 stabilizes AR protein by phosphorylation at a site(s) distinct from Ser-81. Moreover, these results indicate that increased Cdk1 activity is a mechanism for increasing AR expression and stability in response to low androgen levels in androgen-independent PCas, and that Cdk1 antagonists may enhance responses to androgen-deprivation therapy.
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Affiliation(s)
- Shaoyong Chen
- Hematology–Oncology Division, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215
| | - Youyuan Xu
- Hematology–Oncology Division, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215
| | - Xin Yuan
- Hematology–Oncology Division, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215
| | - Glenn J. Bubley
- Hematology–Oncology Division, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215
| | - Steven P. Balk
- Hematology–Oncology Division, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215
- *To whom correspondence should be addressed. E-mail:
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Logan IR, Gaughan L, McCracken SRC, Sapountzi V, Leung HY, Robson CN. Human PIRH2 enhances androgen receptor signaling through inhibition of histone deacetylase 1 and is overexpressed in prostate cancer. Mol Cell Biol 2006; 26:6502-10. [PMID: 16914734 PMCID: PMC1592843 DOI: 10.1128/mcb.00147-06] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The androgen receptor (AR) is a hormone-dependent transcription factor critically involved in human prostate carcinogenesis. Optimal transcriptional control of androgen-responsive genes by AR may require complex interaction among multiple coregulatory proteins. We have previously shown that the AR coregulator TIP60 can interact with human PIRH2 (hPIRH2). In this study, we uncover important new functional role(s) for hPIRH2 in AR signaling: (i) hPIRH2 interacts with AR and enhances AR-mediated transcription with a dynamic pattern of recruitment to androgen response elements in the prostate-specific antigen (PSA) gene; (ii) hPIRH2 interacts with the AR corepressor HDAC1, leading to reduced HDAC1 protein levels and inhibition of transcriptional repression; (iii) hPIRH2 is required for optimal PSA expression; and (iv) hPIRH2 is involved in prostate cancer cell proliferation. In addition, overexpression of hPIRH2 protein was detected in 73 of 82 (89%) resected prostate cancers, with a strong correlation between increased hPIRH2 expression and aggressive disease, as signified by high Gleason sum scores and the presence of metastatic disease (P = <0.0001 and 0.0004, respectively). Collectively, our data establish hPIRH2 as a key modulator of AR function, opening a new direction for targeted therapy in aggressive human prostate cancer.
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Affiliation(s)
- Ian R Logan
- University of Newcastle Upon Tyne, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Framlington Place, Newcastle Upon Tyne NE2 4HH, United Kingdom
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36
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Faus H, Haendler B. Post-translational modifications of steroid receptors. Biomed Pharmacother 2006; 60:520-8. [PMID: 16949786 DOI: 10.1016/j.biopha.2006.07.082] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Accepted: 07/28/2006] [Indexed: 12/28/2022] Open
Abstract
The multiple physiological functions of steroid hormones have been known for many years. The cloning of the steroid receptors in the mid-1980s led to the concept of ligand-activated transcription factors and to the identification of specific DNA response elements in the regulatory regions of target genes. The next main development was the identification of cofactors with activating or repressing functions, of which several act by modifying histones and locally affecting the chromatin structure. Work from several groups shows that the steroid receptors themselves can also be modified at various positions. Besides the long-known phosphorylation at tyrosines and serine/threonine residues, other covalent additions such as acetylation, ubiquitylation and sumoylation have been evidenced for steroid receptors in recent years. These modifications affect receptor stability and activity, and provide potential mechanisms for cell- or gene-specific regulation. A better understanding of the impact of these post-translational modifications (PTMs) on steroid receptor function should help in the identification of novel ligands with improved clinical profiles.
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Affiliation(s)
- H Faus
- Corporate Research Oncology, Schering AG, D-13342 Berlin, Germany
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37
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Agapova OA, Malone PE, Hernandez MR. A neuroactive steroid 5alpha-androstane-3alpha,17beta-diol regulates androgen receptor level in astrocytes. J Neurochem 2006; 98:355-63. [PMID: 16638015 DOI: 10.1111/j.1471-4159.2006.03879.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Optic nerve head (ONH) astrocytes from patients with glaucomatous optic neuropathy exhibit increased production of 5alpha-androstane-3alpha,17beta-diol (3alpha-diol), a neuroactive metabolite of 5alpha-dihydrotestosterone (5alpha-DHT). To determine whether ONH astrocytes are androgen target cells, and whether 3alpha-diol is capable of regulating astrocyte functions, we studied the response of human ONH astrocytes to 3alpha-diol compared with 17beta-hydroxy-17alpha-methyl-estra-4,9,11-trien-3-one (R1881), a synthetic 5alpha-DHT agonist. In ONH astrocytes, both 3alpha-diol and R1881 increased protein levels of androgen receptor (AR) and glial fibrillary acidic protein (GFAP), however, only R1881 also increased the AR mRNA level and astrocyte proliferation. Both R1881 and 3alpha-diol rapidly activate the mitogen-activated protein kinase (MAPK) signaling pathway in ONH astrocytes, as confirmed by phosphorylation of extracellular signal-regulated kinase (ERK). 3Alpha-diol also activates the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. 3Alpha-diol regulates the increase of AR protein level and the phosphorylation through the PI3K/Akt pathway, whereas R1881 regulates them through the MAPK/ERK pathway. Our findings demonstrate that human ONH astrocytes are androgen target cells and respond to androgens by the rapid activation of cell signaling. The activation of the PI3K/Akt pathway by 3alpha-diol may regulate various properties of astrocytes, including cell motility and survival, and may play a role in the formation and maintenance of the reactive phenotype of ONH astrocytes in glaucoma.
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Affiliation(s)
- Olga A Agapova
- Department of Ophthalmology and Visual Sciences, Washington University, School of Medicine, Saint Louis, Missouri 63110, USA.
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38
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Mulholland DJ, Dedhar S, Wu H, Nelson CC. PTEN and GSK3beta: key regulators of progression to androgen-independent prostate cancer. Oncogene 2006; 25:329-37. [PMID: 16421604 DOI: 10.1038/sj.onc.1209020] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Prostate cancer (PrCa) is characterized by progression from an androgen-dependent phenotype to one that is inevitably androgen independent (AI) and lethal. Recent evidence strongly suggests that the phosphatidylinositol-3-kinase/Akt (PI3K/Akt) and androgen receptor (AR) signalling pathways provide prostatic epithelium with the necessary signalling events to escape the apoptotic response associated with androgen withdrawal therapy. Silencing of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and glycogen synthase kinase beta (GSK3beta) are frequently associated with advanced PrCa systems and likely serve critical roles in promoting AR and PI3K/Akt gain-of-function. That PTEN negatively regulates AR and is sufficient to promote metastatic PrCa in murine models strongly implies its role as a gatekeeper of progressive PrCa. In human PrCa, PTEN loss is correlated with substantial increases in Akt(Ser473) and integrin-linked kinase expression, both of which promote Ser(9) phospho-inhibition of GSK3beta and inactivation of apoptotic factors. Sufficient evidence also suggests that GSK3beta is not only a critical regulator of proproliferative signalling but also a promiscuous one as PI3K/Akt pools of GSK3beta are, at least in part, functionally interchangeable with those of the Wnt/beta-catenin pathway. Thus, GSK3beta may serve not only as a mediator of PI3K/Akt activation but may also regulate the potent transactivation and proproliferative effects that Wnt3a and beta-catenin confer upon AR. These data suggest that prostate-specific activation of GSK3beta may serve as a viable pharmacological option. Thus, in this review, we emphasize that temporal changes in GSK3beta and PTEN expression during progression to AI PrCa are important factors when considering the potential for therapies targeting the oncogenic contributions of PI3K/Akt and AR signalling pathways.
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Affiliation(s)
- D J Mulholland
- Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, CA 90095, USA.
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Mantoni TS, Reid G, Garrett MD. Androgen receptor activity is inhibited in response to genotoxic agents in a p53-independent manner. Oncogene 2006; 25:3139-49. [PMID: 16434973 DOI: 10.1038/sj.onc.1209347] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The androgen receptor (AR) is fundamental to androgen signalling within the prostate gland, and deregulation of its activity is frequently linked to the development of prostate cancer. Advanced prostate cancer is often treated with chemotherapy and most of these drugs exert their function by generating genotoxic stress such as DNA damage. We have investigated here the effects of genotoxic agents used in chemotherapeutic regimens on AR function and expression. We have discovered that endogenous AR activity in LNCaP cells is inhibited in response to the chemotherapeutic agents etoposide and cisplatin. This loss of AR activity is not caused by a change in cell cycle distribution, a change in subcellular localisation of the AR nor by induction of apoptosis. In addition, we found that inhibition of AR activity in response to genotoxic stress is independent of p53 function. Interestingly, our studies revealed that genotoxic stress inhibits the hormone-stimulated recruitment of AR to androgen response elements. Thus, we report for the first time a mechanism by which the AR activity is inhibited in response to different chemotherapeutic agents.
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40
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Mellinghoff IK, Vivanco I, Kwon A, Tran C, Wongvipat J, Sawyers CL. HER2/neu kinase-dependent modulation of androgen receptor function through effects on DNA binding and stability. Cancer Cell 2004; 6:517-27. [PMID: 15542435 DOI: 10.1016/j.ccr.2004.09.031] [Citation(s) in RCA: 265] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 08/05/2004] [Accepted: 09/21/2004] [Indexed: 02/07/2023]
Abstract
Given the role of the EGFR/HER2 family of tyrosine kinases in breast cancer, we dissected the molecular basis of EGFR/HER2 kinase signaling in prostate cancer. Using the small molecule dual EGFR/HER2 inhibitor PKI-166, we show that the biologic effects of EGFR/HER-2 pathway inhibition are caused by reduced AR transcriptional activity. Additional genetic and pharmacologic experiments show that this modulation of AR function is mediated by the HER2/ERBB3 pathway, not by EGFR. This HER2/ERBB3 signal stabilizes AR protein levels and optimizes binding of AR to promoter/enhancer regions of androgen-regulated genes. Surprisingly, the downstream signaling pathway responsible for these effects appears to involve kinases other than Akt. These data suggest that the HER2/ERBB3 pathway is a critical target in hormone-refractory prostate cancer.
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Affiliation(s)
- Ingo K Mellinghoff
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
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