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Jamshidi M, Keshavarzi F, Amini S, Laher I, Gheysarzadeh A, Davari K. Targeting androgen receptor (AR) with a synthetic peptide increases apoptosis in triple negative breast cancer and AR-expressing prostate cancer cell lines. Cancer Rep (Hoboken) 2024; 7:e1922. [PMID: 37903548 PMCID: PMC10809188 DOI: 10.1002/cnr2.1922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 11/01/2023] Open
Abstract
BACKGROUND The androgen receptor (AR) has been studied as an approach to cancer therapy. AIMS We used human breast cancer-derived cells with high, low, and very low expression levels of AR, in addition to prostate cancer-derived LNCaP and DU-145 cells as a positive and negative controls to examine apoptosis caused by a synthetic peptide that targets ARs. METHODS AND RESULTS The peptide was produced to inhibit AR transactivation in breast cancer cell lines. We then measured cell viability, caspase-3 activity, and the ratio of Bax/Bcl-2. The findings indicated that the peptide (100-500 nM) in the presence of dihydrotestosterone (DHT) reduced cell growth in cells with high and low expression level of AR (p < .001), but not in cells with very low levels of AR. Treatment with 100-500 nM of peptide activated caspase-3 and increased the ratio of Bax/Bcl-2 in cells with high and low expression levels of AR. Also, increasing concentrations of the peptide (100-500 nM) reduced BrdU incorporation in the presence of DHT and promoted apoptosis in cells with high and low expression levels of AR (p < .001). CONCLUSION The findings indicate the peptide significantly increased apoptosis in cancer cells.
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Affiliation(s)
- Mazdak Jamshidi
- Department of Biology, Sanandaj BranchIslamic Azad UniversitySanandajIran
| | - Fatemeh Keshavarzi
- Department of Biology, Sanandaj BranchIslamic Azad UniversitySanandajIran
| | - Sabrieh Amini
- Department of Biology, Sanandaj BranchIslamic Azad UniversitySanandajIran
| | - Ismail Laher
- Department of Anesthesiology, Pharmacology and TherapeuticsThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Ali Gheysarzadeh
- Department of Clinical BiochemistryIlam University of Medical SciencesIlamIran
| | - Kambiz Davari
- Department of Biology, Sanandaj BranchIslamic Azad UniversitySanandajIran
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2
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Yu X, Yi P, Hamilton RA, Shen H, Chen M, Foulds CE, Mancini MA, Ludtke SJ, Wang Z, O'Malley BW. Structural Insights of Transcriptionally Active, Full-Length Androgen Receptor Coactivator Complexes. Mol Cell 2020; 79:812-823.e4. [PMID: 32668201 DOI: 10.1016/j.molcel.2020.06.031] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/01/2020] [Accepted: 06/18/2020] [Indexed: 01/15/2023]
Abstract
Steroid receptors activate gene transcription by recruiting coactivators to initiate transcription of their target genes. For most nuclear receptors, the ligand-dependent activation function domain-2 (AF-2) is a primary contributor to the nuclear receptor (NR) transcriptional activity. In contrast to other steroid receptors, such as ERα, the activation function of androgen receptor (AR) is largely dependent on its ligand-independent AF-1 located in its N-terminal domain (NTD). It remains unclear why AR utilizes a different AF domain from other receptors despite that NRs share similar domain organizations. Here, we present cryoelectron microscopy (cryo-EM) structures of DNA-bound full-length AR and its complex structure with key coactivators, SRC-3 and p300. AR dimerization follows a unique head-to-head and tail-to-tail manner. Unlike ERα, AR directly contacts a single SRC-3 and p300. The AR NTD is the primary site for coactivator recruitment. The structures provide a basis for understanding assembly of the AR:coactivator complex and its domain contributions for coactivator assembly and transcriptional regulation.
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Affiliation(s)
- Xinzhe Yu
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ping Yi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ross A Hamilton
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hong Shen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Muyuan Chen
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Charles E Foulds
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael A Mancini
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Steven J Ludtke
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhao Wang
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Bert W O'Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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3
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Skowron KJ, Booker K, Cheng C, Creed S, David BP, Lazzara PR, Lian A, Siddiqui Z, Speltz TE, Moore TW. Steroid receptor/coactivator binding inhibitors: An update. Mol Cell Endocrinol 2019; 493:110471. [PMID: 31163202 PMCID: PMC6645384 DOI: 10.1016/j.mce.2019.110471] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/30/2019] [Accepted: 05/30/2019] [Indexed: 12/14/2022]
Abstract
The purpose of this review is to highlight recent developments in small molecules and peptides that block the binding of coactivators to steroid receptors. These coactivator binding inhibitors bind at the coregulator binding groove, also known as Activation Function-2, rather than at the ligand-binding site of steroid receptors. Steroid receptors that have been targeted with coactivator binding inhibitors include the androgen receptor, estrogen receptor and progesterone receptor. Coactivator binding inhibitors may be useful in some cases of resistance to currently prescribed therapeutics. The scope of the review includes small-molecule and peptide coactivator binding inhibitors for steroid receptors, with a particular focus on recent compounds that have been assayed in cell-based models.
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Affiliation(s)
- Kornelia J Skowron
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Kenneth Booker
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Changfeng Cheng
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Simone Creed
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Brian P David
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Phillip R Lazzara
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Amy Lian
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Zamia Siddiqui
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Thomas E Speltz
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA; Department of Chemistry, University of Chicago, 929 E. 57th Street, E547, Chicago, IL, 60637, USA
| | - Terry W Moore
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA; University of Illinois Cancer Center, University of Illinois at Chicago, 1801 W. Taylor Street, Chicago, IL, 60612, USA.
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4
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Song T, Li J. New Insights into the Binding Mechanism of Co-regulator BUD31 to AR AF2 Site: Structural Determination and Analysis of the Mutation Effect. Curr Comput Aided Drug Des 2019; 16:45-53. [PMID: 31057123 PMCID: PMC6967182 DOI: 10.2174/1573409915666190502153307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/19/2019] [Accepted: 04/18/2019] [Indexed: 12/01/2022]
Abstract
Introduction Androgen Receptor (AR) plays a pivotal role in the development of male sex and contributes to prostate cancer growth. Different from other nuclear receptors that bind to the co-regulator LxxLL motif in coregulator peptide interaction, the AR Ligand Binding Domain (LBD) prefers to bind to the FxxLF motif. BUD31, a novel co-regulator with FxxLF motif, has been demonstrated to suppress wild-type and mutated AR-mediated prostate cancer growth. Methods To find out the interaction mechanisms of BUD31 with WT/T877A/W741L AR complex, molecular dynamics simulations were employed to study the complex BUD31 and WT/mutant ARs. The molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) results demonstrated that T877A and W741L point mutations can reduce the binding affinity between BUD31 and AR. The RMSF and dynamic cross-correlation analysis indicated that amino acid point mutations can affect the motions of loop residues in the AR structure. Results These results indicated that AR co-regulator binding site AF2 can serve as a target for drug discovery to solve the resistance problem.
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Affiliation(s)
- Tianqing Song
- School of Pharmacy, Lanzhou University, 199 West Donggang Rd., 730000 Lanzhou, China
| | - Jiazhong Li
- School of Pharmacy, Lanzhou University, 199 West Donggang Rd., 730000 Lanzhou, China
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5
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Wang S, Ekoue DN, Raj GV, Kittler R. Targeting the turnover of oncoproteins as a new avenue for therapeutics development in castration-resistant prostate cancer. Cancer Lett 2018; 438:86-96. [PMID: 30217566 PMCID: PMC6186492 DOI: 10.1016/j.canlet.2018.09.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/23/2018] [Accepted: 09/03/2018] [Indexed: 12/19/2022]
Abstract
The current therapeutic armamentarium for castration-resistant prostate cancer (CRPC) includes second-generation agents such as the Androgen Receptor (AR) inhibitor enzalutamide and the androgen synthesis inhibitor abiraterone acetate, immunotherapies like sipuleucel-T, chemotherapies including docetaxel and cabazitaxel and the radiopharmaceutical radium 223 dichloride. However, relapse of CRPC resistant to these therapeutic modalities occur rapidly. The mechanisms of resistance to these treatments are complex, including specific mutations or alternative splicing of oncogenic proteins. An alternative approach to treating CRPC may be to target the turnover of these molecular drivers of CRPC. In this review, the mechanisms by which protein stability of several oncoproteins such as AR, ERG, GR, CYP17A1 and MYC, will be discussed, as well as how these findings could be translated into novel therapeutic agents.
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Affiliation(s)
- Shan Wang
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Dede N Ekoue
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ganesh V Raj
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ralf Kittler
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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6
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Willett CS, Wilson EM. Evolution of Melanoma Antigen-A11 (MAGEA11) During Primate Phylogeny. J Mol Evol 2018; 86:240-253. [PMID: 29574604 DOI: 10.1007/s00239-018-9838-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 03/21/2018] [Indexed: 12/19/2022]
Abstract
Melanoma antigen-A11 (MAGE-A11) is an X-linked and primate-specific steroid hormone receptor transcriptional coregulator and proto-oncogenic protein whose increased expression promotes the growth of prostate cancer. The MAGEA11 gene is expressed at low levels in normal human testis, ovary, and endometrium, and at highest levels in castration-resistant prostate cancer. Annotated genome predictions throughout the surviving primate lineage show that MAGEA11 acquired three 5' coding exons unique within the MAGEA subfamily during the evolution of New World monkeys (NWM), Old World monkeys (OWM), and apes. MAGE-A11 in all primates has a conserved FXXIF coactivator-binding motif that suggests interaction with p160 coactivators contributed to its early evolution as a transcriptional coregulator. An ancestral form of MAGE-A11 in the more distantly related lemur has significant amino acid sequence identity with human MAGE-A11, but lacks coregulator activity based on the absence of the three 5' coding exons that include a nuclear localization signal (NLS). NWM MAGE-A11 has greater amino acid sequence identity than lemur to human MAGE-A11, but inframe premature stop codons suggest that MAGEA11 is a pseudogene in NWM. MAGE-A11 in OWM and apes has nearly identical 5' coding exon amino acid sequence and conserved interaction sites for p300 acetyltransferase and cyclin A. We conclude that the evolution of MAGEA11 within the lineage leading to OWM and apes resulted in steroid hormone receptor transcriptional coregulator activity through the acquisition of three 5' coding exons that include a NLS sequence and nonsynonymous substitutions required to interact with cell cycle regulatory proteins and transcription factors.
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Affiliation(s)
- Christopher S Willett
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599-7500, USA
| | - Elizabeth M Wilson
- Laboratories for Reproductive Biology, Department of Pediatrics, Lineberger Comprehensive Cancer Center, and Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599-7500, USA.
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7
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Characterization of a novel androgen receptor (AR) coregulator RIPK1 and related chemicals that suppress AR-mediated prostate cancer growth via peptide and chemical screening. Oncotarget 2017; 8:69508-69519. [PMID: 29050220 PMCID: PMC5642495 DOI: 10.18632/oncotarget.17843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 04/27/2017] [Indexed: 11/25/2022] Open
Abstract
Using bicalutamide-androgen receptor (AR) DNA binding domain-ligand binding domain as bait, we observed enrichment of FxxFY motif-containing peptides. Protein database searches revealed the presence of receptor-interacting protein kinase 1 (RIPK1) harboring one FxxFY motif. RIPK1 interacted directly with AR and suppressed AR transactivation in a dose-dependent manner. Domain mapping experiments showed that the FxxFY motif in RIPK1 is critical for interactions with AR and the death domain of RIPK1 plays a crucial role in its inhibitory effect on transactivation. In terms of tissue expression, RIPK1 levels were markedly higher in benign prostate hyperplasia and non-cancerous tissue regions relative to the tumor area. With the aid of computer modeling for screening of chemicals targeting activation function 2 (AF-2) of AR, we identified oxadiazole derivatives as good candidates and subsequently generated a small library of these compounds. A number of candidates could effectively suppress AR transactivation and AR-related functions in vitro and in vivo with tolerable toxicity via inhibiting AR-peptide, AR-coregulator and AR N-C interactions. Combination of these chemicals with antiandrogen had an additive suppressive effect on AR transcriptional activity. Our collective findings may pave the way in creating new strategies for the development and design of anti-AR drugs.
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8
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Biron E, Bédard F. Recent progress in the development of protein-protein interaction inhibitors targeting androgen receptor-coactivator binding in prostate cancer. J Steroid Biochem Mol Biol 2016. [PMID: 26196120 DOI: 10.1016/j.jsbmb.2015.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The androgen receptor (AR) is a key regulator for the growth, differentiation and survival of prostate cancer cells. Identified as a primary target for the treatment of prostate cancer, many therapeutic strategies have been developed to attenuate AR signaling in prostate cancer cells. While frontline androgen-deprivation therapies targeting either the production or action of androgens usually yield favorable responses in prostate cancer patients, a significant number acquire treatment resistance. Known as the castration-resistant prostate cancer (CRPC), the treatment options are limited for this advanced stage. It has been shown that AR signaling is restored in CRPC due to many aberrant mechanisms such as AR mutations, amplification or expression of constitutively active splice-variants. Coregulator recruitment is a crucial regulatory step in AR signaling and the direct blockade of coactivator binding to AR offers the opportunity to develop therapeutic agents that would remain effective in prostate cancer cells resistant to conventional endocrine therapies. Structural analyses of the AR have identified key surfaces involved in protein-protein interaction with coregulators that have been recently used to design and develop promising AR-coactivator binding inhibitors. In this review we will discuss the design and development of small-molecule inhibitors targeting the AR-coactivator interactions for the treatment of prostate cancer.
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Affiliation(s)
- Eric Biron
- Faculty of Pharmacy and Centre de recherche en endocrinologie moléculaire et oncologique et génomique humaine, Université Laval, Canada; Laboratory of Medicinal Chemistry, CHU de Québec Research Centre, G1 V 4G2, Québec, QC, Canada.
| | - François Bédard
- Faculty of Pharmacy and Centre de recherche en endocrinologie moléculaire et oncologique et génomique humaine, Université Laval, Canada; Laboratory of Medicinal Chemistry, CHU de Québec Research Centre, G1 V 4G2, Québec, QC, Canada
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9
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Tran MK, Kurakula K, Koenis DS, de Vries CJM. Protein-protein interactions of the LIM-only protein FHL2 and functional implication of the interactions relevant in cardiovascular disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:219-28. [PMID: 26548523 DOI: 10.1016/j.bbamcr.2015.11.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/02/2015] [Accepted: 11/03/2015] [Indexed: 11/26/2022]
Abstract
FHL2 belongs to the LIM-domain only proteins and contains four and a half LIM domains, each of which are composed of two zinc finger structures. FHL2 exhibits specific interaction with proteins exhibiting diverse functions, including transmembrane receptors, transcription factors and transcription co-regulators, enzymes, and structural proteins. The function of these proteins is regulated by FHL2, which modulates intracellular signal transduction pathways involved in a plethora of cellular tasks. The present review summarizes the current knowledge on the protein interactome of FHL2 and provides an overview of the functional implication of these interactions in apoptosis, migration, and regulation of nuclear receptor function. FHL2 was originally identified in the heart and there is extensive literature available on the role of FHL2 in the cardiovascular system, which is also summarized in this review.
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Affiliation(s)
- M Khang Tran
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Kondababu Kurakula
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Duco S Koenis
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Carlie J M de Vries
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Hsu CL, Liu JS, Lin AC, Yang CH, Chung WH, Wu WG. Minoxidil may suppress androgen receptor-related functions. Oncotarget 2015; 5:2187-97. [PMID: 24742982 PMCID: PMC4039155 DOI: 10.18632/oncotarget.1886] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Although minoxidil has been used for more than two decades to treat androgenetic alopecia (AGA), an androgen-androgen receptor (AR) pathway-dominant disease, its precise mechanism of action remains elusive. We hypothesized that minoxidil may influence the AR or its downstream signaling. These tests revealed that minoxidil suppressed AR-related functions, decreasing AR transcriptional activity in reporter assays, reducing expression of AR targets at the protein level, and suppressing AR-positive LNCaP cell growth. Dissecting the underlying mechanisms, we found that minoxidil interfered with AR-peptide, AR-coregulator, and AR N/C-terminal interactions, as well as AR protein stability. Furthermore, a crystallographic analysis using the AR ligand-binding domain (LBD) revealed direct binding of minoxidil to the AR in a minoxidil-AR-LBD co-crystal model, and surface plasmon resonance assays demonstrated that minoxidil directly bound the AR with a Kd value of 2.6 μM. Minoxidil also suppressed AR-responsive reporter activity and decreased AR protein stability in human hair dermal papilla cells. The current findings provide evidence that minoxidil could be used to treat both cancer and age-related disease, and open a new avenue for applications of minoxidil in treating androgen-AR pathway-related diseases.
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Affiliation(s)
- Cheng-Lung Hsu
- Division of Hematology-Oncology, Departments of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 333, Taiwan, ROC
| | | | | | | | | | - Wen-Guey Wu
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan, ROC
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11
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Hsu CL, Liu JS, Wu PL, Guan HH, Chen YL, Lin AC, Ting HJ, Pang ST, Yeh SD, Ma WL, Chen CJ, Wu WG, Chang C. Identification of a new androgen receptor (AR) co-regulator BUD31 and related peptides to suppress wild-type and mutated AR-mediated prostate cancer growth via peptide screening and X-ray structure analysis. Mol Oncol 2014; 8:1575-87. [PMID: 25091737 DOI: 10.1016/j.molonc.2014.06.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/12/2014] [Accepted: 06/12/2014] [Indexed: 12/26/2022] Open
Abstract
Treatment with individual anti-androgens is associated with the development of hot-spot mutations in the androgen receptor (AR). Here, we found that anti-androgens-mt-ARs have similar binary structure to the 5α-dihydrotestosterone-wt-AR. Phage display revealed that these ARs bound to similar peptides, including BUD31, containing an Fxx(F/H/L/W/Y)Y motif cluster with Tyr in the +5 position. Structural analyses of the AR-LBD-BUD31 complex revealed formation of an extra hydrogen bond between the Tyr+5 residue of the peptide and the AR. Functional studies showed that BUD31-related peptides suppressed AR transactivation, interrupted AR N-C interaction, and suppressed AR-mediated cell growth. Combination of peptide screening and X-ray structure analysis may serve as a new strategy for developing anti-ARs that simultaneously suppress both wt and mutated AR function.
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Affiliation(s)
- Cheng-Lung Hsu
- The George Whipple Lab for Cancer Research, Department of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA; Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 333, Taiwan
| | - Jai-Shin Liu
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 333, Taiwan; Department of Physics, Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Po-Long Wu
- National Synchrotron Radiation Center, Hsinchu 300, Taiwan
| | - Hong-Hsiang Guan
- National Synchrotron Radiation Center, Hsinchu 300, Taiwan; Department of Physics, Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yuh-Ling Chen
- The George Whipple Lab for Cancer Research, Department of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA; Institute of Oral Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - An-Chi Lin
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 333, Taiwan
| | - Huei-Ju Ting
- The George Whipple Lab for Cancer Research, Department of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - See-Tong Pang
- Division of Urology, Department of Surgery, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 333, Taiwan
| | - Shauh-Der Yeh
- The George Whipple Lab for Cancer Research, Department of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Wen-Lung Ma
- The George Whipple Lab for Cancer Research, Department of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA; Sex Hormone Research Center, China Medical University/Hospital, Taichung 104, Taiwan
| | - Chung-Jung Chen
- National Synchrotron Radiation Center, Hsinchu 300, Taiwan; Department of Physics, Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Wen-Guey Wu
- National Synchrotron Radiation Center, Hsinchu 300, Taiwan; Department of Physics, Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan.
| | - Chawnshang Chang
- The George Whipple Lab for Cancer Research, Department of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA; Sex Hormone Research Center, China Medical University/Hospital, Taichung 104, Taiwan.
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12
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Abstract
The RBR (RING-BetweenRING-RING) or TRIAD [two RING fingers and a DRIL (double RING finger linked)] E3 ubiquitin ligases comprise a group of 12 complex multidomain enzymes. This unique family of E3 ligases includes parkin, whose dysfunction is linked to the pathogenesis of early-onset Parkinson's disease, and HOIP (HOIL-1-interacting protein) and HOIL-1 (haem-oxidized IRP2 ubiquitin ligase 1), members of the LUBAC (linear ubiquitin chain assembly complex). The RBR E3 ligases share common features with both the larger RING and HECT (homologous with E6-associated protein C-terminus) E3 ligase families, directly catalysing ubiquitin transfer from an intrinsic catalytic cysteine housed in the C-terminal domain, as well as recruiting thioester-bound E2 enzymes via a RING domain. Recent three-dimensional structures and biochemical findings of the RBRs have revealed novel protein domain folds not previously envisioned and some surprising modes of regulation that have raised many questions. This has required renaming two of the domains in the RBR E3 ligases to more accurately reflect their structures and functions: the C-terminal Rcat (required-for-catalysis) domain, essential for catalytic activity, and a central BRcat (benign-catalytic) domain that adopts the same fold as the Rcat, but lacks a catalytic cysteine residue and ubiquitination activity. The present review discusses how three-dimensional structures of RBR (RING1-BRcat-Rcat) E3 ligases have provided new insights into our understanding of the biochemical mechanisms of these important enzymes in ubiquitin biology.
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13
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Jehle K, Cato L, Neeb A, Muhle-Goll C, Jung N, Smith EW, Buzon V, Carbó LR, Estébanez-Perpiñá E, Schmitz K, Fruk L, Luy B, Chen Y, Cox MB, Bräse S, Brown M, Cato ACB. Coregulator control of androgen receptor action by a novel nuclear receptor-binding motif. J Biol Chem 2014; 289:8839-51. [PMID: 24523409 DOI: 10.1074/jbc.m113.534859] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The androgen receptor (AR) is a ligand-activated transcription factor that is essential for prostate cancer development. It is activated by androgens through its ligand-binding domain (LBD), which consists predominantly of 11 α-helices. Upon ligand binding, the last helix is reorganized to an agonist conformation termed activator function-2 (AF-2) for coactivator binding. Several coactivators bind to the AF-2 pocket through conserved LXXLL or FXXLF sequences to enhance the activity of the receptor. Recently, a small compound-binding surface adjacent to AF-2 has been identified as an allosteric modulator of the AF-2 activity and is termed binding function-3 (BF-3). However, the role of BF-3 in vivo is currently unknown, and little is understood about what proteins can bind to it. Here we demonstrate that a duplicated GARRPR motif at the N terminus of the cochaperone Bag-1L functions through the BF-3 pocket. These findings are supported by the fact that a selective BF-3 inhibitor or mutations within the BF-3 pocket abolish the interaction between the GARRPR motif(s) and the BF-3. Conversely, amino acid exchanges in the two GARRPR motifs of Bag-1L can impair the interaction between Bag-1L and AR without altering the ability of Bag-1L to bind to chromatin. Furthermore, the mutant Bag-1L increases androgen-dependent activation of a subset of AR targets in a genome-wide transcriptome analysis, demonstrating a repressive function of the GARRPR/BF-3 interaction. We have therefore identified GARRPR as a novel BF-3 regulatory sequence important for fine-tuning the activity of the AR.
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Affiliation(s)
- Katja Jehle
- From the Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
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14
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Fiandalo MV, Wu W, Mohler JL. The role of intracrine androgen metabolism, androgen receptor and apoptosis in the survival and recurrence of prostate cancer during androgen deprivation therapy. Curr Drug Targets 2013; 14:420-40. [PMID: 23565755 PMCID: PMC3991464 DOI: 10.2174/1389450111314040004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 02/21/2013] [Accepted: 02/22/2013] [Indexed: 11/22/2022]
Abstract
Prostate cancer (CaP) is the most frequently diagnosed cancer and leading cause of cancer death in American men. Almost all men present with advanced CaP and some men who fail potentially curative therapy are treated with androgen deprivation therapy (ADT). ADT is not curative and CaP recurs as the lethal phenotype. The goal of this review is to apply our current understanding of CaP and castration-recurrent CaP (CR-CaP) to earlier studies that characterized ADT and the molecular mechanisms that facilitate the transition from androgen-stimulated CaP to CR-CaP. Reexamination of earlier studies also may provide a better understanding of how more newly recognized mechanisms, such as intracrine metabolism, may be involved with the early events that allow CaP survival after initiation of ADT and subsequent development of CR-CaP.
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Affiliation(s)
- Michael V. Fiandalo
- Department of Urology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Wenjie Wu
- Department of Urology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - James L. Mohler
- Department of Urology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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15
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Caboni L, Lloyd DG. Beyond the ligand-binding pocket: targeting alternate sites in nuclear receptors. Med Res Rev 2012; 33:1081-118. [PMID: 23344935 DOI: 10.1002/med.21275] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Nuclear receptors (NRs) are a family of ligand-modulated transcription factors with significant therapeutic relevance from metabolic disorders and inflammation to cancer, neurodegenerative, and psychiatric disorders. Drug discovery efforts are typically concentrated on modulating the natural ligand action within the ligand-binding pocket (LBP) in the C-terminal ligand-binding domain (LBD). Drawbacks of LBP-based strategies include physiological alterations due to disruption of ligand binding and difficulties in achieving tissue specificity. Furthermore, the lack of a "pure" and predictable mechanism of action predisposes such intervention toward drug resistance. Recent outstanding progress in our understanding of NR biology has shifted the focus of drug discovery efforts from inside to outside the LBP, affording consideration to the interaction between NRs and coactivator proteins, the interaction between NRs and DNA and the NRs' ligand-independent functions. This review encompasses such currently available NR non-LBP-based interventions and their potential application in therapy or as specific tools to probe NR biology.
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Affiliation(s)
- Laura Caboni
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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16
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Nyrönen TH, Söderholm AA. Structural basis for computational screening of non-steroidal androgen receptor ligands. Expert Opin Drug Discov 2012; 5:5-20. [PMID: 22823968 DOI: 10.1517/17460440903468680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Deep structural and chemical understanding of the protein target and computational methods for detection of receptor-selective ligands are important for the early drug discovery in the steroid receptor field. AREAS COVERED IN THIS REVIEW This review focuses on the use of currently available structural information of the androgen receptor (AR) and known AR ligands to make computational strategies for the discovery of AR ligands in order to offer new chemical platforms for drug development. WHAT THE READER WILL GAIN AR is a challenging target for drug discovery and modeling even if there is a wealth of experimental data available. First, only the active structure of AR is currently known, which hampers the design of AR antagonists. Second, the structural similarity between the ligand-binding sites of AR and its mutated forms and closely related steroid receptors (SRs) such as progesterone receptors presents challenges for the development of drugs with receptor-selective function. TAKE HOME MESSAGE Research indicates that a very small chemical change in the structure of a non-steroidal ligand can cause a complete change in its activity. One source of this effect arises from binding to similar binding sites in related SRs and other proteins in the signaling pathway. Currently, computational methods are not able to predict the subtle differences between AR ligand activities but modeling does offer the possibility of generating new lead structures that might have the desired properties.
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Affiliation(s)
- Tommi H Nyrönen
- CSC - IT Center for Science Ltd., P.O. Box 405, Espoo, FI-02101, Finland +358 9 4572235 ; +358 9 4572302 ;
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17
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Kollara A, Brown TJ. Expression and function of nuclear receptor co-activator 4: evidence of a potential role independent of co-activator activity. Cell Mol Life Sci 2012; 69:3895-909. [PMID: 22562579 PMCID: PMC3492700 DOI: 10.1007/s00018-012-1000-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 04/13/2012] [Accepted: 04/17/2012] [Indexed: 12/22/2022]
Abstract
Nuclear receptor coactivator 4 (NcoA4), also known as androgen receptor-associated protein 70 (ARA70), was initially discovered as a component of Ret-Fused Gene expressed in a subset of papillary thyroid carcinomas. Subsequent studies have established NcoA4 as a coactivator for a variety of nuclear receptors, including peroxisome proliferator activated receptors α and γ, and receptors for steroid hormones, vitamins D and A, thyroid hormone, and aryl hydrocarbons. While human NcoA4 has both LXXLL and FXXLF motifs that mediate p160 coactivator nuclear receptor interactions, this ubiquitously expressed protein lacks clearly defined functional domains. Several studies indicate that NcoA4 localizes predominantly to the cytoplasm and affects ligand-binding specificity of the androgen receptor, which has important implications for androgen-independent prostate cancer. Two NcoA4 variants, which may exert differential activities, have been identified in humans. Recent studies suggest that NcoA4 may play a role in development, carcinogenesis, inflammation, erythrogenesis, and cell cycle progression that may be independent of its role as a receptor coactivator. This review summarizes what is currently known of the structure, expression, regulation, and potential functions of this unique protein in cancerous and non-cancerous pathologies.
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Affiliation(s)
- Alexandra Kollara
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 25 Orde Street, 6-1001TB, Toronto, ON, M5T 3H7, Canada
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18
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van de Wijngaart DJ, Dubbink HJ, van Royen ME, Trapman J, Jenster G. Androgen receptor coregulators: recruitment via the coactivator binding groove. Mol Cell Endocrinol 2012; 352:57-69. [PMID: 21871527 DOI: 10.1016/j.mce.2011.08.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 08/08/2011] [Accepted: 08/10/2011] [Indexed: 02/08/2023]
Abstract
Androgens are key regulators of male sexual differentiation and essential for development and maintenance of male reproductive tissues. The androgens testosterone and dihydrotestosterone mediate their effect by binding to, and activation of the androgen receptor (AR). Upon activation, the AR is able to recognize specific DNA sequences in gene promoters and enhancers from where it recruits coregulators to orchestrate chromatin remodeling and transcription regulation. The number of proteins that bind to the AR has surpassed 200 and many of them enhance (coactivator) or repress (corepressor) its transactivating capacity. For most of these coregulators, their AR binding interface and their exact mode of action still needs to be elucidated, but for some of the more classical coactivators and corepressors, we gained insight in their working mechanisms. Of particular interest are specific sequences (LxxLL and FxxLF-like motifs) in a subset of coactivators that interact with the AR via a coactivator binding groove in the ligand-binding domain. As compared to other steroid receptors, the conformation of the AR coactivator binding pocket is unique and preferentially binds FxxLF-like motifs. This predisposition is expected to contribute to the regulation of specific sets of target genes via recruitment of selected coregulators. This review provides an overview of these (inter)actions with a focus on the unique characteristics of the AR coactivator binding groove.
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19
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Askew EB, Minges JT, Hnat AT, Wilson EM. Structural features discriminate androgen receptor N/C terminal and coactivator interactions. Mol Cell Endocrinol 2012; 348:403-10. [PMID: 21664945 PMCID: PMC3199032 DOI: 10.1016/j.mce.2011.03.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 03/25/2011] [Accepted: 03/31/2011] [Indexed: 11/20/2022]
Abstract
Human androgen receptor (AR) transcriptional activity involves interdomain and coactivator interactions with the agonist-bound AR ligand binding domain (LBD). Structural determinants of the AR NH(2)- and carboxyl-terminal interaction between the AR NH(2)-terminal FXXLF motif and activation function 2 (AF2) in the LBD were shown previously by crystallography. In this report, we provide evidence for a region in AR LBD helix 12 outside the AF2 binding cleft that facilitates interactions with the FXXLF and LXXLL motifs. Mutagenesis of glutamine 902 to alanine in AR LBD helix 12 (Q902A) disrupted AR FXXLF motif binding to AF2, but enhanced coactivator LXXLL motif binding. Functional compensation for defective FXXLF motif binding by AR-Q902A was suggested by the slower dissociation rate of bound androgen. Functional importance of glutamine 902 was indicated by the charged residue germline mutation Q902R that caused partial androgen insensitivity, and a similar somatic mutation Q902K reported in prostate cancer, both of which increased the androgen dissociation rate and decreased AR transcriptional activity. High affinity equilibrium androgen binding was retained by alanine substitution mutations at Tyr-739 in AR LBD helix 5 or Lys-905 in helix 12 structurally adjacent to AF2, whereas transcriptional activity decreased and the androgen dissociation increased. Deleterious effects of these loss of function mutations were rescued by the helix stabilizing AR prostate cancer somatic mutation H874Y. Sequence NH(2)-terminal to the AR FXXLF motif contributed to the AR NH(2)- and carboxyl-terminal interaction based on greater AR-2-30 FXXLF motif peptide binding to the agonist-bound AR LBD than a shorter AR-20-30 FXXLF motif peptide. We conclude that helix 12 residues outside the AF2 binding cleft modulate AR transcriptional activity by providing flexibility to accommodate FXXLF or LXXLL motif binding.
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Affiliation(s)
| | | | | | - Elizabeth M. Wilson
- Corresponding author: EM Wilson, Laboratories for Reproductive Biology, University of North Carolina at Chapel Hill, NC 27599-7500 USA, TEL 919-966-5168, FAX 919-966-2203
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20
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van de Wijngaart DJ, Dubbink HJ, Molier M, de Vos C, Jenster G, Trapman J. Inhibition of androgen receptor functions by gelsolin FxxFF peptide delivered by transfection, cell-penetrating peptides, and lentiviral infection. Prostate 2011; 71:241-53. [PMID: 20690138 DOI: 10.1002/pros.21238] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Prostate cancer (PC) growth is dependent on the androgen-androgen receptor (AR) axis. Because current androgen ablation therapies of PC lead to resistance, novel approaches to block AR activity are urgently needed. METHODS We inhibited AR function beyond the level of hormone binding by blockade of the coactivator groove in the ligand-binding domain (LBD) using a high-affinity gelsolin FxxFF peptide. Following peptide selection, the effect of the gelsolin FxxFF peptide on AR functions was determined in Hep3B cells that were transiently transfected with pM-peptide expression vectors or were incubated with synthetic gelsolin FxxFF peptide coupled to the TAT cell-penetrating peptide. Lentiviruses expressing the gelsolin FxxFF peptide were used to study endogenous AR target gene expression in LNCaP cells. RESULTS pM-Gelsolin FxxFF efficiently interfered with AR N/C interaction and specifically inhibited AR-regulated reporter gene activity. The peptide did not inhibit progesterone receptor (PR) and glucocorticoid receptor (GR) activity, nor constitutively active gene promoters. The peptide also specifically blocked in vitro interactions of AR LBD with peptides. Like the gelsolin FxxFF peptide expressed by an expression vector, synthetic TAT-gelsolin FxxFF peptide efficiently blocked AR N/C interaction and inhibited full-length AR-regulated reporter gene activity. It hardly affected PR and GR activity, but the effect on constitutively active promoters was variable. Lentiviral gelsolin FxxFF peptide inhibited expression of KLK2 and NDRG1, but hardly affected PSA and TMPRSS2. CONCLUSIONS Our results show that the AR coactivator groove may function as a target to overcome therapeutic failure that arises during current androgen ablation therapies.
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21
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Abstract
High-affinity binding of testosterone or dihydrotestosterone to the androgen receptor (AR) triggers the androgen-dependent AR NH2- and carboxyl-terminal (N/C) interaction between the AR NH2-terminal FXXLF motif and the activation function 2 (AF2) hydrophobic binding surface in the ligand-binding domain. The functional importance of the AR N/C interaction is supported by naturally occurring loss-of-function AR AF2 mutations where AR retains high-affinity androgen binding but is defective in AR FXXLF motif binding. Ligands with agonist activity in vivo such as testosterone, dihydrotestosterone, and the synthetic anabolic steroids induce the AR N/C interaction and increase AR transcriptional activity in part by slowing the dissociation rate of bound ligand and stabilizing AR against degradation. AR ligand-binding domain competitive antagonists inhibit the agonist-dependent AR N/C interaction. Although the human AR N/C interaction is important for transcriptional activity, it has an inhibitory effect on transcriptional activity from AF2 by competing for p160 coactivator LXXLL motif binding. The primate-specific AR coregulatory protein, melanoma antigen gene protein-A11 (MAGE-A11), modulates the AR N/C interaction through a direct interaction with the AR FXXLF motif. Inhibition of AF2 transcriptional activity by the AR N/C interaction is relieved by AR FXXLF motif binding to the F-box region of MAGE-11. Described here are methods to measure the androgen-dependent AR N/C interdomain interaction and the influence of transcriptional coregulators.
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Affiliation(s)
- Elizabeth M Wilson
- Laboratories for Reproductive Biology, Lineberger Comprehensive Cancer Center, Department of Pediatrics, University of North Carolina, Chapel Hill, NC 27599, USA.
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22
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Yang J, Chang CY, Safi R, Morgan J, McDonnell DP, Fuller PJ, Clyne CD, Young MJ. Identification of ligand-selective peptide antagonists of the mineralocorticoid receptor using phage display. Mol Endocrinol 2010; 25:32-43. [PMID: 21106883 DOI: 10.1210/me.2010-0193] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The mineralocorticoid receptor (MR) is a member of the nuclear receptor superfamily. Pathological activation of the MR causes cardiac fibrosis and heart failure, but clinical use of MR antagonists is limited by the renal side effect of hyperkalemia. The glucocorticoid cortisol binds the MR with equivalent affinity to that of the mineralocorticoids aldosterone and deoxycorticosterone. In nonepithelial tissues, including the myocardium, which do not express the cortisol-inactivating enzyme 11β hydroxysteroid dehydrogenase 2, cortisol has been implicated in the activation of MR. The mechanisms for ligand- and tissue-specific actions of the MR are undefined. Over the past decade, it has become clear that coregulator proteins are critical for nuclear receptor-mediated gene expression. A subset of these coregulators may confer specificity to MR-mediated responses. To evaluate whether different physiological ligands can induce distinct MR conformations that underlie differential coregulator recruitment and ligand-specific gene regulation, we utilized phage display technology to screen 10(8) 19mer peptides for their interaction with the MR in the presence of agonist ligands. We identified ligand-selective MR-interacting peptides that acted as potent antagonists of MR-mediated transactivation. This represents a novel mechanism of MR antagonism that may be manipulated in the rational design of a ligand- or tissue-selective MR modulator to treat diseases like heart failure without side effects such as hyperkalemia.
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Affiliation(s)
- Jun Yang
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
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23
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Jin L, Li Y. Structural and functional insights into nuclear receptor signaling. Adv Drug Deliv Rev 2010; 62:1218-26. [PMID: 20723571 DOI: 10.1016/j.addr.2010.08.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 08/08/2010] [Accepted: 08/10/2010] [Indexed: 01/14/2023]
Abstract
Nuclear receptors are important transcriptional factors that share high sequence identity and conserved domains, including a DNA-binding domain (DBD) and a ligand-binding domain (LBD). The LBD plays a crucial role in ligand-mediated nuclear receptor activity. Hundreds of different crystal structures of nuclear receptors have revealed a general mechanism for the molecular basis of ligand binding and ligand-mediated regulation of nuclear receptors. Despite the conserved fold of nuclear receptor LBDs, the ligand-binding pocket is the least conserved region among different nuclear receptor LBDs. Structural comparison and analysis show that several features of the pocket, like the size and also the shape, have contributed to the ligand binding affinity and specificity. In addition, the plastic nature of the ligand-binding pockets in many nuclear receptors provides greater flexibility to further accommodate specific ligands with a variety of conformations. Nuclear receptor coactivators usually contain multiple LXXLL motifs that are used to interact with nuclear receptors. The nuclear receptors respond differently to distinct ligands and readily exchange their ligands in different environments. The conformational flexibility of the AF-2 helix allows the nuclear receptor to sense the presence of the bound ligands, either an agonist or an antagonist, and to recruit the coactivators or corepressors that ultimately determine the transcriptional activation or repression of nuclear receptors.
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24
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Nedelsky NB, Pennuto M, Smith RB, Palazzolo I, Moore J, Nie Z, Neale G, Taylor JP. Native functions of the androgen receptor are essential to pathogenesis in a Drosophila model of spinobulbar muscular atrophy. Neuron 2010; 67:936-52. [PMID: 20869592 DOI: 10.1016/j.neuron.2010.08.034] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2010] [Indexed: 12/25/2022]
Abstract
Spinobulbar muscular atrophy (SBMA) is a neurodegenerative disease caused by expansion of a polyglutamine tract in the androgen receptor (AR). This mutation confers toxic function to AR through unknown mechanisms. Mutant AR toxicity requires binding of its hormone ligand, suggesting that pathogenesis involves ligand-induced changes in AR. However, whether toxicity is mediated by native AR function or a novel AR function is unknown. We systematically investigated events downstream of ligand-dependent AR activation in a Drosophila model of SBMA. We show that nuclear translocation of AR is necessary, but not sufficient, for toxicity and that DNA binding by AR is necessary for toxicity. Mutagenesis studies demonstrated that a functional AF-2 domain is essential for toxicity, a finding corroborated by a genetic screen that identified AF-2 interactors as dominant modifiers of degeneration. These findings indicate that SBMA pathogenesis is mediated by misappropriation of native protein function, a mechanism that may apply broadly to polyglutamine diseases.
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Affiliation(s)
- Natalia B Nedelsky
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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25
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Askew EB, Bai S, Blackwelder AJ, Wilson EM. Transcriptional synergy between melanoma antigen gene protein-A11 (MAGE-11) and p300 in androgen receptor signaling. J Biol Chem 2010; 285:21824-36. [PMID: 20448036 DOI: 10.1074/jbc.m110.120600] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Androgen receptor (AR)-mediated gene regulation involves interactions with coregulatory proteins that include the melanoma antigen gene protein-A11 (MAGE-11). To understand the functional significance of sequence similarity between MAGE-11 and the adenovirus early protein E1A, we determined whether MAGE-11 contributes to AR transcriptional activity through an interaction with p300, a potent and ubiquitous transcriptional regulator. Here, we report that MAGE-11 interacts with the NH(2)-terminal region of p300 through the MAGE-11 MXXIF motif (185)MXXIF(189), with transcriptional activity depending on the MAGE-11 F-box and MAPK phosphorylation. The MAGE-11- and p300-dependent increase in AR transactivation required the NH(2)-terminal regions of AR and p300, p300 acetyltransferase activity, and the AR FXXLF motif (23)FQNLF(27) interaction with MAGE-11. MAGE-11 linked AR to p300 and the p160 coactivator, transcriptional intermediary protein 2 (TIF2). The p300 NH(2)-terminal FXXLF motif (33)FGSLF(37) was required for transcriptional activation by TIF2. Increased expression of p300 decreased the ubiquitinylation of MAGE-11 and transiently increased endogenous MAGE-11 levels. Autoacetylation of p300 and decreased acetylation of TIF2 were evident in the MAGE-11, p300, and TIF2 complex. The studies suggest that MAGE-11 links NH(2)-terminal domains of AR and p300 to promote transcriptional synergy through a cadre of FXXLF-related interacting motifs.
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Affiliation(s)
- Emily B Askew
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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26
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van de Wijngaart DJ, Dubbink HJ, Molier M, de Vos C, Trapman J, Jenster G. Functional screening of FxxLF-like peptide motifs identifies SMARCD1/BAF60a as an androgen receptor cofactor that modulates TMPRSS2 expression. Mol Endocrinol 2009; 23:1776-86. [PMID: 19762545 DOI: 10.1210/me.2008-0280] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Androgen receptor (AR) transcriptional activity is tightly regulated by interacting cofactors and cofactor complexes. The best described cofactor interaction site in the AR is the hormone-induced coactivator binding groove in the ligand-binding domain, which serves as a high-affinity docking site for FxxLF-like motifs. This study aimed at identifying novel AR cofactors by in silico selection and functional screening of FxxLF-like peptide motifs. Candidate interacting motifs were selected from a proteome-wide screening and from a supervised screening focusing on components of protein complexes involved in transcriptional regulation. Of the 104 peptides tested, 12 displayed moderate to strong in vivo hormone-dependent interactions with AR. For three of these, ZBTB16/PLZF, SMARCA4/BRG1, and SMARCD1/BAF60a, the full-length protein was tested for interaction with AR. Of these, BAF60a, a subunit of the SWI/SNF chromatin remodeling complex, displayed hormone-dependent interactions with AR through its FxxFF motif. Vice versa, recruitment of BAF60a by the AR required an intact coactivator groove. BAF60a depletion by small interfering RNA in LNCaP cells demonstrated differential effects on expression of endogenous AR target genes. AR-driven expression of TMPRSS2 was almost completely blocked by BAF60a small interfering RNA. In summary, our data demonstrate that BAF60a directly interacts with the coactivator groove in the AR ligand-binding domain via its FxxFF motif, thereby selectively activating specific AR-driven promoters.
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Affiliation(s)
- Dennis J van de Wijngaart
- Department of Urology, Josephine Nefkens Institute, Erasmus Medical College, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
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27
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Liu D, Yin C, Zhang Y, Tian L, Li T, Li D, Ma D, Guo Y, Wang Y. Human CMTM2/CKLFSF2 enhances the ligand-induced transactivation of the androgen receptor. Sci Bull (Beijing) 2009. [DOI: 10.1007/s11434-009-0092-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Vaz B, Möcklinghoff S, Brunsveld L. Targeting the Nuclear Receptor–Cofactor Interaction. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/9783527623297.ch2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Berntzen G, Andersen JT, Ustgård K, Michaelsen TE, Mousavi SA, Qian JD, Kristiansen PE, Lauvrak V, Sandlie I. Identification of a high affinity FcgammaRIIA-binding peptide that distinguishes FcgammaRIIA from FcgammaRIIB and exploits FcgammaRIIA-mediated phagocytosis and degradation. J Biol Chem 2008; 284:1126-35. [PMID: 18957413 DOI: 10.1074/jbc.m803584200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
FcgammaRIIA is a key activating receptor linking immune complex formation with cellular effector functions. FcgammaRIIA has 93% identity with an inhibitory receptor, FcgammaRIIB, which negatively regulates FcgammaRIIA. FcgammaRIIA is important in the therapeutic action of several monoclonal antibodies. Binding molecules that discriminate FcgammaRIIA from FcgammaRIIB may optimize receptor activity and serve as a lead for development of therapeutics with FcgammaRIIA as a key target. Here we report the use of phage display libraries to select short peptides with distinct FcgammaRIIA binding properties. An 11-mer peptide (WAWVWLTETAV) was characterized that bound FcgammaRIIA with a K(d) of 500 nm. It mediated cell internalization and degradation of a model antigen. The peptide-binding site on FcgammaRIIA was shown to involve Phe(163) and the IgG binding amino acids Trp(90) and Trp(113). It is thus overlapping but not identical to that of IgG. Neither activating receptors FcgammaRI and FcgammaRIII, nor FcgammaRIIB, all of which lack Phe(163), bound the peptide.
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Affiliation(s)
- Gøril Berntzen
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway
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30
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Ting HJ, Chang C. Actin associated proteins function as androgen receptor coregulators: an implication of androgen receptor's roles in skeletal muscle. J Steroid Biochem Mol Biol 2008; 111:157-63. [PMID: 18590822 DOI: 10.1016/j.jsbmb.2008.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Accepted: 06/05/2008] [Indexed: 11/28/2022]
Abstract
This review of androgen receptor (AR) coregulators, which also function as actin-binding proteins, intends to establish the connection between actin cytoskeletal components and androgen signaling, especially in skeletal muscle. In cellular and animal models, androgen activated AR modulates myoblasts proliferation, promotes sexual dimorphic muscle development, and alters muscle fiber type. In the clinical setting, administration of anabolic androgens can decrease cachexia and speed wound healing. During myogenesis and regeneration of skeletal muscle in embryo and adult, the membrane of myoblasts fuse and the actin cytoskeleton is rearranged to form an alignment with myosin to form myotubes then ultimately the myofibrils. Contraction of skeletal muscle promotes the growth of myocytes by coordinating signals from the neuromuscular junction to intra-myofibrils through costameres, the functional structure comprised of signal proteins closely associated with actin filaments and involved in muscular dystrophy. Therefore, the discovery of actin-binding proteins functioning as AR coregulators implies that androgen signaling is tightly regulated during the process of the development and regeneration of skeletal muscle. The search for selective androgen receptor modulators (SARM) that act precisely in skeletal muscle instead of other tissues could target the engineering of a SARM-AR complex that selectively recruits these coregulators.
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Affiliation(s)
- Huei-Ju Ting
- Department of Pathology and Urology, The Cancer Center, University of Rochester Medical Center, Rochester, NY 14642, USA
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Centenera MM, Harris JM, Tilley WD, Butler LM. The contribution of different androgen receptor domains to receptor dimerization and signaling. Mol Endocrinol 2008; 22:2373-82. [PMID: 18617596 DOI: 10.1210/me.2008-0017] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The androgen receptor (AR) is a ligand-activated transcription factor of the nuclear receptor superfamily that plays a critical role in male physiology and pathology. Activated by binding of the native androgens testosterone and 5alpha-dihydrotestosterone, the AR regulates transcription of genes involved in the development and maintenance of male phenotype and male reproductive function as well as other tissues such as bone and muscle. Deregulation of AR signaling can cause a diverse range of clinical conditions, including the X-linked androgen insensitivity syndrome, a form of motor neuron disease known as Kennedy's disease, and male infertility. In addition, there is now compelling evidence that the AR is involved in all stages of prostate tumorigenesis including initiation, progression, and treatment resistance. To better understand the role of AR signaling in the pathogenesis of these conditions, it is important to have a comprehensive understanding of the key determinants of AR structure and function. Binding of androgens to the AR induces receptor dimerization, facilitating DNA binding and the recruitment of cofactors and transcriptional machinery to regulate expression of target genes. Various models of dimerization have been described for the AR, the most well characterized interaction being DNA-binding domain- mediated dimerization, which is essential for the AR to bind DNA and regulate transcription. Additional AR interactions with potential to contribute to receptor dimerization include the intermolecular interaction between the AR amino terminal domain and ligand-binding domain known as the N-terminal/C-terminal interaction, and ligand-binding domain dimerization. In this review, we discuss each form of dimerization utilized by the AR to achieve transcriptional competence and highlight that dimerization through multiple domains is necessary for optimal AR signaling.
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Affiliation(s)
- Margaret M Centenera
- Dame Roma Mitchell Cancer Research Laboratories, Discipline of Medicine, The University of Adelaide and Hanson Institute, PO Box 14, Rundle Mall, Adelaide, South Australia 5000, Australia
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Bai S, Grossman G, Yuan L, Lessey BA, French FS, Young SL, Wilson EM. Hormone control and expression of androgen receptor coregulator MAGE-11 in human endometrium during the window of receptivity to embryo implantation. Mol Hum Reprod 2008; 14:107-16. [PMID: 18048459 PMCID: PMC2701302 DOI: 10.1093/molehr/gam080] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The androgen receptor (AR) is a ligand-activated transcription factor of the male and female reproductive tracts whose activity is modulated by coregulator binding. We recently identified melanoma antigen gene protein-11 (MAGE-11) of the MAGEA gene family that functions as an AR coregulator by binding the AR N-terminal FXXLF motif. Here we report that MAGE-11 is expressed in a temporal fashion in endometrium of normally cycling women. Highest levels of MAGE-11 mRNA and protein occur in the mid-secretory stage, coincident with the window of uterine receptivity to embryo implantation. Studies in human endometrial cell lines together with the hormone profile of the menstrual cycle and pattern of estrogen receptor-alpha expression in cycling endometrium suggest the rise in MAGE-11 mRNA results from down-regulation by estradiol during the proliferative phase and up-regulation by cyclic AMP signaling in the early and mid-secretory stage. In agreement with its coregulatory function, MAGE-11 localizes with AR in glandular epithelial cell nuclei in the mid-secretory stage. The increase in AR protein in the mid-secretory endometrium without an increase in AR mRNA suggests MAGE-11 stabilizes AR in glandular epithelial cell nuclei. This was supported by expression studies at low androgen levels indicating AR stabilization by MAGE-11 dependent on the AR N-terminal transactivation domain. The results suggest that MAGE-11 functions as a coregulator that increases AR transcriptional activity during the establishment of uterine receptivity in the human female.
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Affiliation(s)
- Suxia Bai
- Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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Epidermal-growth-factor-dependent phosphorylation and ubiquitinylation of MAGE-11 regulates its interaction with the androgen receptor. Mol Cell Biol 2008; 28:1947-63. [PMID: 18212060 DOI: 10.1128/mcb.01672-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The androgen receptor (AR) is a ligand-activated transcription factor that interacts with coregulatory proteins during androgen-dependent gene regulation. Melanoma antigen gene protein 11 (MAGE-11) is an AR coregulator that specifically binds the AR NH(2)-terminal FXXLF motif and modulates the AR NH(2)- and carboxyl-terminal N/C interaction to increase AR transcriptional activity. Here we demonstrate that epidermal growth factor (EGF) signaling increases androgen-dependent AR transcriptional activity through the posttranslational modification of MAGE-11. EGF in the presence of dihydrotestosterone stabilizes the AR-MAGE complex through the site-specific phosphorylation of MAGE-11 at Thr-360 and ubiquitinylation at Lys-240 and Lys-245. The time-dependent EGF-induced increase in AR transcriptional activity by MAGE-11 is mediated through AR activation functions 1 and 2 in association with the increased turnover of AR and MAGE-11. The results reveal a dynamic mechanism whereby growth factor signaling increases AR transcriptional activity through the covalent modification of an AR-specific coregulatory protein. Sequence conservation of the MAGE-11 phosphorylation and ubiquitinylation sites throughout the MAGE gene family suggests common regulatory mechanisms for this group of cancer-testis antigens.
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The Sarcomere and the Nucleus: Functional Links to Hypertrophy, Atrophy and Sarcopenia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 642:176-91. [DOI: 10.1007/978-0-387-84847-1_13] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Heemers HV, Tindall DJ. Androgen receptor (AR) coregulators: a diversity of functions converging on and regulating the AR transcriptional complex. Endocr Rev 2007; 28:778-808. [PMID: 17940184 DOI: 10.1210/er.2007-0019] [Citation(s) in RCA: 502] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Androgens, acting through the androgen receptor (AR), are responsible for the development of the male phenotype during embryogenesis, the achievement of sexual maturation at puberty, and the maintenance of male reproductive function and behavior in adulthood. In addition, androgens affect a wide variety of nonreproductive tissues. Moreover, aberrant androgen action plays a critical role in multiple pathologies, including prostate cancer and androgen insensitivity syndromes. The formation of a productive AR transcriptional complex requires the functional and structural interaction of the AR with its coregulators. In the last decade, an overwhelming and ever increasing number of proteins have been proposed to possess AR coactivating or corepressing characteristics. Intriguingly, a vast diversity of functions has been ascribed to these proteins, indicating that a multitude of cellular functions and signals converge on the AR to regulate its function. The current review aims to provide an overview of the AR coregulator proteins identified to date and to propose a classification of these AR coregulator proteins according to the function(s) ascribed to them. Taken together, this approach will increase our understanding of the cellular pathways that converge on the AR to ensure an appropriate transcriptional response to androgens.
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Affiliation(s)
- Hannelore V Heemers
- Department of Urology Research, Mayo Clinic, Rochester, Minnesota 55905, USA
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Brooke GN, Parker MG, Bevan CL. Mechanisms of androgen receptor activation in advanced prostate cancer: differential co-activator recruitment and gene expression. Oncogene 2007; 27:2941-50. [PMID: 18037956 DOI: 10.1038/sj.onc.1210955] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Prostate tumour growth depends on androgens; hence treatment includes androgen ablation and anti-androgens. Eventually tumours progress and in approximately 30% of patients this is associated with mutation of the androgen receptor. Several receptor variants associated with advanced disease show promiscuous activation by other hormones and anti-androgens. Such loss of specificity could promote receptor activation, hence tumour growth, in the absence of conventional ligands, explaining therapy failure. We aimed to elucidate mechanisms by which alternative ligands promote receptor activation. The three most commonly identified variants in tumours (with amino-acid substitutions H874Y, T877A and T877S) and wild-type receptor showed differences in co-activator recruitment dependent upon ligand and the interaction motif utilized. Co-expression and knockdown of co-activators that bind via leucine or phenylalanine motifs, combined with chromatin immunoprecipitation and quantitative PCR, revealed these preferences extend to co-activator recruitment in vivo and affect receptor activity at the transcriptional level, with subsequent effects on target gene regulation. The findings suggest that mutant receptors, activated by alternative ligands, drive growth via different mechanisms to androgen-activated wild-type receptor. Tumours may hence behave differently dependent upon any androgen receptor mutation present and what ligand is driving growth, as distinct subsets of genes may be regulated.
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Affiliation(s)
- G N Brooke
- Androgen Signalling Laboratory, Department of Oncology, Imperial College London, London, UK
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37
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Askew EB, Gampe RT, Stanley TB, Faggart JL, Wilson EM. Modulation of androgen receptor activation function 2 by testosterone and dihydrotestosterone. J Biol Chem 2007; 282:25801-16. [PMID: 17591767 PMCID: PMC4075031 DOI: 10.1074/jbc.m703268200] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The androgen receptor (AR) is transcriptionally activated by high affinity binding of testosterone (T) or its 5alpha-reduced metabolite, dihydrotestosterone (DHT), a more potent androgen required for male reproductive tract development. The molecular basis for the weaker activity of T was investigated by determining T-bound ligand binding domain crystal structures of wild-type AR and a prostate cancer somatic mutant complexed with the AR FXXLF or coactivator LXXLL peptide. Nearly identical interactions of T and DHT in the AR ligand binding pocket correlate with similar rates of dissociation from an AR fragment containing the ligand binding domain. However, T induces weaker AR FXXLF and coactivator LXXLL motif interactions at activation function 2 (AF2). Less effective FXXLF motif binding to AF2 accounts for faster T dissociation from full-length AR. T can nevertheless acquire DHT-like activity through an AR helix-10 H874Y prostate cancer mutation. The Tyr-874 mutant side chain mediates a new hydrogen bonding scheme from exterior helix-10 to backbone protein core helix-4 residue Tyr-739 to rescue T-induced AR activity by improving AF2 binding of FXXLF and LXXLL motifs. Greater AR AF2 activity by improved core helix interactions is supported by the effects of melanoma antigen gene protein-11, an AR coregulator that binds the AR FXXLF motif and targets AF2 for activation. We conclude that T is a weaker androgen than DHT because of less favorable T-dependent AR FXXLF and coactivator LXXLL motif interactions at AF2.
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Affiliation(s)
- Emily B. Askew
- Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599
- Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Robert T. Gampe
- Computational and Structural Sciences, Division of Molecular Discovery Research, GlaxoSmithKline, Research Triangle Park, North Carolina 27709
| | - Thomas B. Stanley
- Computational and Structural Sciences, Division of Molecular Discovery Research, GlaxoSmithKline, Research Triangle Park, North Carolina 27709
| | - Jonathan L. Faggart
- Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Elizabeth M. Wilson
- Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599
- Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599
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Cantin L, Faucher F, Couture JF, de Jésus-Tran KP, Legrand P, Ciobanu LC, Fréchette Y, Labrecque R, Singh SM, Labrie F, Breton R. Structural characterization of the human androgen receptor ligand-binding domain complexed with EM5744, a rationally designed steroidal ligand bearing a bulky chain directed toward helix 12. J Biol Chem 2007; 282:30910-9. [PMID: 17711855 DOI: 10.1074/jbc.m705524200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Antiandrogens are commonly used to treat androgen-dependent disorders. The currently used drugs unfortunately possess very weak affinity for the human AR (hAR), thus indicating the need to develop new high-affinity steroidal antiandrogens. Our compounds are specially designed to impede repositioning of the mobile carboxyl-terminal helix 12, which blocks the ligand-dependent transactivation function (AF-2) located in the AR ligand-binding domain (ARLBD). Using crystal structures of the hARLBD, we first found that H12 could be directly reached from the ligand-binding pocket (LBP) by a chain positioned on the C18 atom of an androgen steroid nucleus. A set of 5alpha-dihydrotestosterone-derived molecules bearing various C18 chains were thus synthesized and tested for their capacity to bind hAR and act as antagonists. Although most of those having very high affinity for hAR were agonists, several very potent antagonists were obtained, confirming the structural importance of the C18 chain. To understand the role of the C18 chain in their agonistic/antagonistic properties, the structure of the hARLBD complexed with one of these agonists, EM5744, was determined at a 1.65-A resolution. We have identified new interactions involving Gln(738), Met(742), and His(874) that explain both the high affinity of this compound and the inability of its bulky chain to prevent the repositioning of H12. This structural information will be helpful to refine the structure of the chains placed on the C18 atom to obtain efficient H12-directed steroidal antiandrogens.
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Affiliation(s)
- Line Cantin
- Oncology and Molecular Endocrinology Research Center, Laval University Medical Center (CHUL) and Laval University, Québec G1V 4G2, Canada
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39
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Horne FM, Blithe DL. Progesterone receptor modulators and the endometrium: changes and consequences. Hum Reprod Update 2007; 13:567-80. [PMID: 17630398 DOI: 10.1093/humupd/dmm023] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Progesterone receptor modulators (PRMs) have been used for contraceptive research, as well as for treatment of fibroids, endometriosis and heavy or irregular menstrual bleeding. Long-term treatment with these compounds results in changes to the endometrium resulting in potential confusion in trying to characterize endometrial biopsies. A meeting was held to discuss the properties of PRMs, the effects of perturbed hormonal control of the endometrium and the need for further understanding of the biology of progesterone receptor action to facilitate the development of new PRMs. A panel of pathologists was convened to evaluate endometrial changes associated with a minimum of three months of chronic treatment with PRMs. Four different agents were used in the treatment regimens but the pathologists were blinded to treatment regimen or agent. The panel agreed that the endometrial biopsies did not fit into a classification of either proliferative or secretory endometrium but exhibited an unusual architecture that could be characterized as glandular dilatation. There was little evidence of mitosis, consistent with a proposed anti-proliferative effect of PRMs. The panel concluded that the biopsies did not reveal evidence of safety concern and that pathologists and investigators familiar with endometrial effects of chronic PRM exposure should consider working with pharmaceutical companies and regulatory agencies to develop standard descriptions of PRM-associated endometrial changes as well as the types of histologic changes that would signal a need for intervention.
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McEwan IJ, Lavery D, Fischer K, Watt K. Natural disordered sequences in the amino terminal domain of nuclear receptors: lessons from the androgen and glucocorticoid receptors. NUCLEAR RECEPTOR SIGNALING 2007; 5:e001. [PMID: 17464357 PMCID: PMC1853069 DOI: 10.1621/nrs.05001] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Accepted: 01/02/2007] [Indexed: 11/20/2022]
Abstract
Steroid hormones are a diverse class of structurally related molecules, derived from cholesterol, that include androgens, estrogens, progesterone and corticosteroids. They represent an important group of physiologically active signalling molecules that bind intracellular receptor proteins and regulate genes involved in developmental, reproductive and metabolic processes. The receptor proteins share structurally and functionally related ligand binding and DNA-binding domains, but possess distinct N-terminal domains (NTD) of unique length and amino acids sequence. The NTD contains sequences important for gene regulation, exhibit structure plasticity and are likely to contribute to the specificity of the steroid hormone/receptor response.
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MESH Headings
- Amino Acid Sequence
- Computer Simulation
- Hartnup Disease
- Models, Chemical
- Models, Molecular
- Molecular Sequence Data
- Mutation
- Protein Structure, Tertiary
- Receptors, Androgen/chemistry
- Receptors, Androgen/genetics
- Receptors, Androgen/ultrastructure
- Receptors, Glucocorticoid/chemistry
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/ultrastructure
- Sequence Analysis, Protein
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Affiliation(s)
- Iain J McEwan
- School of Medical Sciences, IMS Building, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK.
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41
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Yang Z, Chang YJ, Miyamoto H, Yeh S, Yao JL, di Sant'Agnese PA, Tsai MY, Chang C. Suppression of androgen receptor transactivation and prostate cancer cell growth by heterogeneous nuclear ribonucleoprotein A1 via interaction with androgen receptor coregulator ARA54. Endocrinology 2007; 148:1340-9. [PMID: 17110431 DOI: 10.1210/en.2006-0716] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The androgen receptor (AR) requires coregulators for its optimal transactivation. Whether AR coregulators also need interacting proteins to modulate their function remains unclear. Here we describe heterogeneous nuclear ribonucleoprotein (hnRNP) A1 as an associated negative modulator for the AR coregulator ARA54. hnRNP A1 selectively suppressed ARA54-enhanced wild-type and mutant AR transactivation via interruption of AR-ARA54 interaction and ARA54 homodimerization. Stable transfection of hnRNP A1 in the LNCaP cells suppressed AR-mediated cell growth and the expression of prostate-specific antigen, and this suppressive effect was abolished by the addition of ARA54-small interfering RNA. Small interfering RNA knockdown of endogenous hnRNP A1 enhanced cell growth and prostate-specific antigen expression in LNCaP cells. These results not only suggest that the loss of hnRNP A1 expression might activate the ARA54-enhanced cell growth and contribute to the prostate cancer progression, but also demonstrate the dual functional roles for ARA54 as an AR coregulator directly and as a mediator for the suppressive effect of hnRNP A1 indirectly. The novel finding that a protein can modulate AR function without direct interaction with AR might provide a new therapeutic approach to battle prostate cancer by targeting AR indirectly with fewer side effects.
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Affiliation(s)
- Zhiming Yang
- George Whipple Lab for Cancer Research, and University of Rochester Medical Center, Rochester, NY 14642, USA
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42
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Bonagura TW, Deng M, Brown TR. A naturally occurring mutation in the human androgen receptor of a subject with complete androgen insensitivity confers binding and transactivation by estradiol. Mol Cell Endocrinol 2007; 263:79-89. [PMID: 17011702 DOI: 10.1016/j.mce.2006.08.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 08/23/2006] [Accepted: 08/24/2006] [Indexed: 10/24/2022]
Abstract
The clinical phenotype of complete androgen insensitivity (CAIS) was associated with a mutation in the human androgen receptor (hAR) gene encoding the amino acid substitution, M745I, in the hAR protein. Transcriptional activation of hAR(M745I) by the synthetic androgen, methyltrienolone (R1881), was reduced compared to wild-type (wt) hAR. The transcriptional co-activator, androgen receptor associated protein 70 (ARA70), failed to enhance transactivation of hAR(M745I) at lower concentrations of R1881 (0.01-0.1 nM), whereas the p160 co-activators, SRC-1 and TIF2, stimulated activity. Transcriptional activity of hAR(M745I) was stimulated by 1 or 10 nM R1881 and activity was further enhanced by co-expression of ARA70 similar to that of the hAR(wt). Transcriptional activity of hAR(wt) was minimally stimulated by estradiol (E2) without or with co-expression of ARA70, whereas 10 or 100 nM E2 increased transactivation by hAR(M745I) of the androgen-responsive MMTV-luciferase reporter gene by 10-fold and activity was further enhanced by ARA70. Increasing concentrations of E2 competed more effectively for binding of R1881 to hAR(M745I) than to hAR(wt), indicative of the preferential binding of E2 to the mutant hAR. Partial tryptic digestion of hAR wt and M745I revealed that activation of the mutant protein was reduced in the presence of R1881. By contrast, tryptic digestion showed that the mutant hAR was activated by the binding of E2. In conclusion, the clinical phenotype of CAIS resulted from a hAR gene mutation encoding hAR(M745I) with reduced binding and transactivation by androgens, but the novel properties of enhanced affinity for and increased transactivation by estradiol.
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Affiliation(s)
- Thomas W Bonagura
- Department of Biochemistry and Molecular Biology, Division of Reproductive Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205-2103, United States
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43
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Affiliation(s)
- Elizabeth M Wilson
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7500, USA
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44
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Yang Z, Chang YJ, Miyamoto H, Ni J, Niu Y, Chen Z, Chen YL, Yao JL, di Sant'Agnese PA, Chang C. Transgelin functions as a suppressor via inhibition of ARA54-enhanced androgen receptor transactivation and prostate cancer cell growth. Mol Endocrinol 2006; 21:343-58. [PMID: 17082327 DOI: 10.1210/me.2006-0104] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The androgen receptor (AR) requires coregulators for its optimal function. However, whether AR coregulators further need interacting protein(s) for their proper function remains unclear. Here we describe transgelin as the first ARA54-associated negative modulator for AR. Transgelin suppressed ARA54-enhanced AR function in ARA54-positive, but not in ARA54-negative, cells. Transgelin suppressed AR transactivation via interruption of ARA54 homodimerization and AR-ARA54 heterodimerization, resulting in the cytoplasmic retention of AR and ARA54. Stable transfection of transgelin in LNCaP cells suppressed AR-mediated cell growth and prostate-specific antigen expression, whereas this suppressive effect was abolished by the addition of ARA54-small interfering RNA. Results from tissue surveys showing decreased expression of transgelin in prostate cancer specimens further strengthened the suppressor role of transgelin. Our findings reveal the novel mechanisms of how transgelin functions as a suppressor to inhibit prostate cancer cell growth. They also demonstrate that AR coregulators, like ARA54, might have dual in vivo roles functioning as both a direct coactivator and as an indirect mediator in AR function. The finding that a protein can modulate AR function without direct interaction with AR might provide a new therapeutic approach, with fewer side effects, to battle prostate cancer by targeting AR indirectly.
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Affiliation(s)
- Zhiming Yang
- George Whipple Laboratory for Cancer Research, University of Rochester Medical Center, 601 Elmwood Avenue, Box 626, Rochester, New York 14642, USA
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45
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Folkertsma S, van Noort PI, de Heer A, Carati P, Brandt R, Visser A, Vriend G, de Vlieg J. The use of in vitro peptide binding profiles and in silico ligand-receptor interaction profiles to describe ligand-induced conformations of the retinoid X receptor alpha ligand-binding domain. Mol Endocrinol 2006; 21:30-48. [PMID: 17038419 DOI: 10.1210/me.2006-0072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
It is hypothesized that different ligand-induced conformational changes can explain the different interactions of nuclear receptors with regulatory proteins, resulting in specific biological activities. Understanding the mechanism of how ligands regulate cofactor interaction facilitates drug design. To investigate these ligand-induced conformational changes at the surface of proteins, we performed a time-resolved fluorescence resonance energy transfer assay with 52 different cofactor peptides measuring the ligand-induced cofactor recruitment to the retinoid X receptor-alpha (RXRalpha) in the presence of 11 compounds. Simultaneously we analyzed the binding modes of these compounds by molecular docking. An automated method converted the complex three-dimensional data of ligand-protein interactions into two-dimensional fingerprints, the so-called ligand-receptor interaction profiles. For a subset of compounds the conformational changes at the surface, as measured by peptide recruitment, correlate well with the calculated binding modes, suggesting that clustering of ligand-receptor interaction profiles is a very useful tool to discriminate compounds that may induce different conformations and possibly different effects in a cellular environment. In addition, we successfully combined ligand-receptor interaction profiles and peptide recruitment data to reveal structural elements that are possibly involved in the ligand-induced conformations. Interestingly, we could predict a possible binding mode of LG100754, a homodimer antagonist that showed no effect on peptide recruitment. Finally, the extensive analysis of the peptide recruitment profiles provided novel insight in the potential cellular effect of the compound; for the first time, we showed that in addition to the induction of coactivator peptide binding, all well-known RXRalpha agonists also induce binding of corepressor peptides to RXRalpha.
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Affiliation(s)
- Simon Folkertsma
- Centre for Molecular and Biomolecular Informatics, University of Nijmegen, 6500 GL Nijmegen, The Netherlands.
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46
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van de Wijngaart DJ, van Royen ME, Hersmus R, Pike ACW, Houtsmuller AB, Jenster G, Trapman J, Dubbink HJ. Novel FXXFF and FXXMF motifs in androgen receptor cofactors mediate high affinity and specific interactions with the ligand-binding domain. J Biol Chem 2006; 281:19407-16. [PMID: 16690616 DOI: 10.1074/jbc.m602567200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Upon hormone binding, a hydrophobic coactivator binding groove is induced in the androgen receptor (AR) ligand-binding domain (LBD). This groove serves as high affinity docking site for alpha-helical FXXLF motifs present in the AR N-terminal domain and in AR cofactors. Study of the amino acid requirements at position +4 of the AR FXXLF motif revealed that most amino acid substitutions strongly reduced or completely abrogated AR LBD interaction. Strong interactions were still observed following substitution of Leu+4 by Phe or Met residues. Leu+4 to Met or Phe substitutions in the FXXLF motifs of AR cofactors ARA54 and ARA70 were also compatible with strong AR LBD binding. Like the corresponding FXXLF motifs, interactions of FXXFF and FXXMF variants of AR and ARA54 motifs were AR specific, whereas variants of the less AR-selective ARA70 motif displayed increased AR specificity. A survey of currently known AR-binding proteins revealed the presence of an FXXFF motif in gelsolin and an FXXMF motif in PAK6. In vivo fluorescence resonance energy transfer and functional protein-protein interaction assays showed direct, efficient, and specific interactions of both motifs with AR LBD. Mutation of these motifs abrogated interaction of gelsolin and PAK6 proteins with AR. In conclusion, we have demonstrated strong interaction of FXXFF and FXXMF motifs to the AR coactivator binding groove, thereby mediating specific binding of a subgroup of cofactors to the AR LBD.
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Affiliation(s)
- Dennis J van de Wijngaart
- Department of Urology, Josephine Nefkens Institute, Erasmus MC, P. O. Box 1738, 3000 DR Rotterdam, The Netherlands
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Dubbink HJ, Hersmus R, Pike ACW, Molier M, Brinkmann AO, Jenster G, Trapman J. Androgen receptor ligand-binding domain interaction and nuclear receptor specificity of FXXLF and LXXLL motifs as determined by L/F swapping. Mol Endocrinol 2006; 20:1742-55. [PMID: 16627595 DOI: 10.1210/me.2005-0348] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The androgen receptor (AR) ligand-binding domain (LBD) binds FXXLF motifs, present in the AR N-terminal domain and AR-specific cofactors, and some LXXLL motifs of nuclear receptor coactivators. We demonstrated that in the context of the AR FXXLF motif many different amino acid residues at positions +2 and +3 are compatible with strong AR LBD interaction, although a preference for E at +2 and K or R at +3 was found. Pairwise systematic analysis of F/L swaps at +1 and +5 in FXXLF and LXXLL motifs showed: 1) F to L substitutions in natural FXXLF motifs abolished AR LBD interaction; 2) binding of interacting LXXLL motifs was unchanged or increased upon L to F substitutions; 3) certain noninteracting LXXLL motifs became strongly AR-interacting FXXLF motifs; whereas 4) other nonbinders remained unaffected by L to F substitutions. All FXXLF motifs, but not the corresponding LXXLL motifs, displayed a strong preference for AR LBD. Progesterone receptor LBD interacted with some FXXLF motifs, albeit always less efficiently than corresponding LXXLL motifs. AR LBD interaction of most FXXLF and LXXLL peptides depended on classical charge clamp residue K720, whereas E897 was less important. Other charged residues lining the AR coactivator-binding groove, K717 and R726, modulated optimal peptide binding. Interestingly, these four charged residues affected binding of individual peptides independent of an F or L at +1 and +5 in swap experiments. In conclusion, F residues determine strong and selective peptide interactions with AR. Sequences flanking the core motif determine the specific mode of FXXLF and LXXLL interactions.
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Affiliation(s)
- Hendrikus J Dubbink
- Department of Pathology, Josephine Nefkens Institute, Erasmus MC, Rotterdam, The Netherlands.
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Lavery D, Mcewan I. Structure and function of steroid receptor AF1 transactivation domains: induction of active conformations. Biochem J 2006; 391:449-64. [PMID: 16238547 PMCID: PMC1276946 DOI: 10.1042/bj20050872] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Steroid hormones are important endocrine signalling molecules controlling reproduction, development, metabolism, salt balance and specialized cellular responses, such as inflammation and immunity. They are lipophilic in character and act by binding to intracellular receptor proteins. These receptors function as ligand-activated transcription factors, switching on or off networks of genes in response to a specific hormone signal. The receptor proteins have a conserved domain organization, comprising a C-terminal LBD (ligand-binding domain), a hinge region, a central DBD (DNA-binding domain) and a highly variable NTD (N-terminal domain). The NTD is structurally flexible and contains surfaces for both activation and repression of gene transcription, and the strength of the transactivation response has been correlated with protein length. Recent evidence supports a structural and functional model for the NTD that involves induced folding, possibly involving alpha-helix structure, in response to protein-protein interactions and structure-stabilizing solutes.
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Affiliation(s)
- Derek N. Lavery
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, U.K
| | - Iain J. Mcewan
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, U.K
- To whom correspondence should be addressed (email )
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Sood VD, Baker D. Recapitulation and design of protein binding peptide structures and sequences. J Mol Biol 2006; 357:917-27. [PMID: 16473368 DOI: 10.1016/j.jmb.2006.01.045] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 01/03/2006] [Accepted: 01/09/2006] [Indexed: 11/23/2022]
Abstract
An important objective of computational protein design is the generation of high affinity peptide inhibitors of protein-peptide interactions, both as a precursor to the development of therapeutics aimed at disrupting disease causing complexes, and as a tool to aid investigators in understanding the role of specific complexes in the cell. We have developed a computational approach to increase the affinity of a protein-peptide complex by designing N or C-terminal extensions which interact with the protein outside the canonical peptide binding pocket. In a first in silico test, we show that by simultaneously optimizing the sequence and structure of three to nine residue peptide extensions starting from short (1-6 residue) peptide stubs in the binding pocket of a peptide binding protein, the approach can recover both the conformations and the sequences of known binding peptides. Comparison with phage display and other experimental data suggests that the peptide extension approach recapitulates naturally occurring peptide binding specificity better than fixed backbone design, and that it should be useful for predicting peptide binding specificities from crystal structures. We then experimentally test the approach by designing extensions for p53 and dystroglycan-based peptides predicted to bind with increased affinity to the Mdm2 oncoprotein and to dystrophin, respectively. The measured increases in affinity are modest, revealing some limitations of the method. Based on these in silico and experimental results, we discuss future applications of the approach to the prediction and design of protein-peptide interactions.
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Affiliation(s)
- Vanita D Sood
- Department of Biochemistry, Box 357350, University of Washington, Seattle, WA 98195, USA
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Lange S, Ehler E, Gautel M. From A to Z and back? Multicompartment proteins in the sarcomere. Trends Cell Biol 2005; 16:11-8. [PMID: 16337382 DOI: 10.1016/j.tcb.2005.11.007] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 10/03/2005] [Accepted: 11/21/2005] [Indexed: 12/11/2022]
Abstract
Sarcomeres, the smallest contractile units of striated muscle, are conventionally perceived as the most regular macromolecular assemblies in biology, with precisely assigned localizations for their constituent proteins. However, recent studies have revealed complex multiple locations for several sarcomere proteins within the sarcomere and other cellular compartments such as the nucleus. Several of these proteins appear to relocalize in response to mechanical stimuli. Here, we review the emerging role of these protein networks as dynamic information switchboards that communicate between the contractile machinery and the nucleus to central pathways controlling cell survival, protein breakdown, gene expression and extracellular signaling.
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Affiliation(s)
- Stephan Lange
- King's College London, Muscle Signalling and Development, The Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, UK
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