1
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Ji Y, Zhang R, Han X, Zhou J. Targeting the N-terminal domain of the androgen receptor: The effective approach in therapy of CRPC. Eur J Med Chem 2023; 247:115077. [PMID: 36587421 DOI: 10.1016/j.ejmech.2022.115077] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 12/31/2022]
Abstract
The androgen receptor (AR) is dominant in prostate cancer (PCa) pathology. Current therapeutic agents for advanced PCa include androgen synthesis inhibitors and AR antagonists that bind to the hormone binding pocket (HBP) at the ligand binding domain (LBD). However, AR amplification, AR splice variants (AR-Vs) expression, and intra-tumoral de novo synthesis of androgens result in the reactivation of AR signalling. The AR N-terminal domain (NTD) plays an essential role in AR transcriptional activity. The AR inhibitor targeting NTD could potentially block the activation of both full-length AR and AR-Vs, thus overcoming major resistance mechanisms to current treatments. This review discusses the progress of research in various NTD inhibitors and provides new insight into the development of AR-NTD inhibitors.
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Affiliation(s)
- Yang Ji
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China; Drug Development and Innovation Center, College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China
| | - Rongyu Zhang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China; Drug Development and Innovation Center, College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China
| | - Xiaoli Han
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China; Drug Development and Innovation Center, College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China
| | - Jinming Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China; Drug Development and Innovation Center, College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China.
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2
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Dahiya UR, Heemers HV. Analyzing the Androgen Receptor Interactome in Prostate Cancer: Implications for Therapeutic Intervention. Cells 2022; 11:936. [PMID: 35326387 PMCID: PMC8946651 DOI: 10.3390/cells11060936] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 12/29/2022] Open
Abstract
The androgen receptor (AR) is a member of the ligand-activated nuclear receptor family of transcription factors. AR's transactivation activity is turned on by the binding of androgens, the male sex steroid hormones. AR is critical for the development and maintenance of the male phenotype but has been recognized to also play an important role in human diseases. Most notably, AR is a major driver of prostate cancer (CaP) progression, which remains the second leading cause of cancer deaths in American men. Androgen deprivation therapies (ADTs) that interfere with interactions between AR and its activating androgen ligands have been the mainstay for treatment of metastatic CaP. Although ADTs are effective and induce remissions, eventually they fail, while the growth of the majority of ADT-resistant CaPs remains under AR's control. Alternative approaches to inhibit AR activity and bypass resistance to ADT are being sought, such as preventing the interaction between AR and its cofactors and coregulators that is needed to execute AR-dependent transcription. For such strategies to be efficient, the 3D conformation of AR complexes needs to be well-understood and AR-regulator interaction sites resolved. Here, we review current insights into these 3D structures and the protein interaction sites in AR transcriptional complexes. We focus on methods and technological approaches used to identify AR interactors and discuss challenges and limitations that need to be overcome for efficient therapeutic AR complex disruption.
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Affiliation(s)
| | - Hannelore V. Heemers
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, NB-40, 9500 Euclid Avenue, Cleveland, OH 44195, USA;
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3
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Roggero CM, Esser V, Duan L, Rice AM, Ma S, Raj GV, Rosen MK, Liu ZP, Rizo J. Poly-glutamine-dependent self-association as a potential mechanism for regulation of androgen receptor activity. PLoS One 2022; 17:e0258876. [PMID: 34986150 PMCID: PMC8730435 DOI: 10.1371/journal.pone.0258876] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/13/2021] [Indexed: 01/01/2023] Open
Abstract
The androgen receptor (AR) plays a central role in prostate cancer. Development of castration resistant prostate cancer (CRPC) requires androgen-independent activation of AR, which involves its large N-terminal domain (NTD) and entails extensive epigenetic changes depending in part on histone lysine demethylases (KDMs) that interact with AR. The AR-NTD is rich in low-complexity sequences, including a polyQ repeat. Longer polyQ sequences were reported to decrease transcriptional activity and to protect against prostate cancer, although they can lead to muscular atrophy. However, the molecular mechanisms underlying these observations are unclear. Using NMR spectroscopy, here we identify weak interactions between the AR-NTD and the KDM4A catalytic domain, and between the AR ligand-binding domain and a central KDM4A region that also contains low-complexity sequences. We also show that the AR-NTD can undergo liquid-liquid phase separation in vitro, with longer polyQ sequences phase separating more readily. Moreover, longer polyQ sequences hinder nuclear localization in the absence of hormone and increase the propensity for formation of AR-containing puncta in the nucleus of cells treated with dihydrotestosterone. These results lead us to hypothesize that polyQ-dependent liquid-liquid phase separation may provide a mechanism to decrease the transcriptional activity of AR, potentially opening new opportunities to design effective therapies against CRPC and muscular atrophy.
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Affiliation(s)
- Carlos M. Roggero
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Victoria Esser
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Lingling Duan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Allyson M. Rice
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Shihong Ma
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Ganesh V. Raj
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michael K. Rosen
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Zhi-Ping Liu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Josep Rizo
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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4
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Sadar MD. Drugging the Undruggable: Targeting the N-Terminal Domain of Nuclear Hormone Receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:311-326. [PMID: 36107327 DOI: 10.1007/978-3-031-11836-4_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This chapter focuses on the development of drugs targeting the N-terminal domain of nuclear hormone receptors, using progress with the androgen receptor as an example. Historically, development of therapies targeting nuclear hormone receptors has focused on the folded C-terminal ligand-binding domain. Therapies were traditionally not developed to target the intrinsically disordered N-terminal domain as it was considered "undruggable". Recent developments have now shown it is possible to direct therapies to the N-terminal domain. This chapter will provide an introduction of the structure and function of the domains of nuclear hormone receptors, followed by a discussion of the rationale supporting the development of N-terminal domain inhibitors. Chemistry and mechanisms of action of small molecule inhibitors will be described with emphasis on N-terminal domain inhibitors developed to the androgen receptor including those in clinical trials.
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Affiliation(s)
- Marianne D Sadar
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer, Vancouver, BC, Canada.
- Department of Pathology and Laboratory Science, University of British Columbia, Vancouver, BC, Canada.
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5
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Eighty Years of Targeting Androgen Receptor Activity in Prostate Cancer: The Fight Goes on. Cancers (Basel) 2021; 13:cancers13030509. [PMID: 33572755 PMCID: PMC7865914 DOI: 10.3390/cancers13030509] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/25/2021] [Accepted: 01/25/2021] [Indexed: 12/24/2022] Open
Abstract
Simple Summary Prostate cancer is the second most common cancer in men world-wide, with nearly 1.3 million new cases each year, and over the next twenty years the incidence and death rate are predicted to nearly double. For decades, this lethal disease has been more or less successfully treated using hormonal therapy, which has the ultimate aim of inhibiting androgen signalling. However, prostate tumours can evade such hormonal therapies in a number of different ways and therapy resistant disease, so-called castration-resistant prostate cancer (CRPC) is the major clinical problem. Somewhat counterintuitively, the androgen receptor remains a key therapy target in CRPC. Here, we explain why this is the case and summarise both new hormone therapy strategies and the recent advances in knowledge of androgen receptor structure and function that underpin them. Abstract Prostate cancer (PCa) is the most common cancer in men in the West, other than skin cancer, accounting for over a quarter of cancer diagnoses in US men. In a seminal paper from 1941, Huggins and Hodges demonstrated that prostate tumours and metastatic disease were sensitive to the presence or absence of androgenic hormones. The first hormonal therapy for PCa was thus castration. In the subsequent eighty years, targeting the androgen signalling axis, where possible using drugs rather than surgery, has been a mainstay in the treatment of advanced and metastatic disease. Androgens signal via the androgen receptor, a ligand-activated transcription factor, which is the direct target of many such drugs. In this review we discuss the role of the androgen receptor in PCa and how the combination of structural information and functional screenings is continuing to be used for the discovery of new drug to switch off the receptor or modify its function in cancer cells.
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6
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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: 90] [Impact Index Per Article: 22.5] [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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7
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Chen X, Wei L, Yang L, Guo W, Guo Q, Zhou Y. Glycolysis inhibition and apoptosis induction in human prostate cancer cells by FV-429-mediated regulation of AR-AKT-HK2 signaling network. Food Chem Toxicol 2020; 143:111517. [PMID: 32619556 DOI: 10.1016/j.fct.2020.111517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 01/22/2023]
Abstract
Prostate cancer (PCa) depends on androgen receptor (AR) signaling to regulate cell metabolism, including glycolysis, and thereby promotes tumor growth. Glycolysis is overactive in PCa and associated with poor prognosis, but the therapeutic efficacy of glycolysis inhibitors has thus far been limited by their inability to induce cell death. FV-429, a flavonoid derivative of Wogonin, is a glycolysis inhibitor that has shown anti-cancer promise. In this study, we used FV-429 as an anti-PCa agent and investigated its mechanisms of action. In vitro, both the glycolytic ability and the viability of PCa cells were inhibited by FV-429. We found that FV-429 could induce mitochondrial dysfunction and apoptosis, with AKT-HK2 signaling pathway playing a key role. In addition, FV-429 had a pro-apoptotic effect on human prostate cancer cells that relied on the inhibition of AR expression and activity. In vivo, FV-429 exerted significant tumor-repressing activity with high safety in the xenograft model using LNCaP cells. In summary, we demonstrated that FV-429 induced glycolysis inhibition and apoptosis in human prostate cancer cells by downregulating the AR-AKT-HK2 signaling network, making FV-429 a promising candidate as one therapeutic agent for advanced PCa.
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Affiliation(s)
- Xian Chen
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China
| | - Libin Wei
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China
| | - Liliang Yang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China
| | - Wenjing Guo
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China
| | - Qinglong Guo
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China.
| | - Yuxin Zhou
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China.
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8
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Sadar MD. Discovery of drugs that directly target the intrinsically disordered region of the androgen receptor. Expert Opin Drug Discov 2020; 15:551-560. [PMID: 32100577 DOI: 10.1080/17460441.2020.1732920] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: Intrinsically disordered proteins (IDPs) and regions (IDRs) lack stable three-dimensional structure making drug discovery challenging. A validated therapeutic target for diseases such as prostate cancer is the androgen receptor (AR) which has a disordered amino-terminal domain (NTD) that contains all of its transcriptional activity. Drug discovery against the AR-NTD is of intense interest as a potential treatment for disease such as advanced prostate cancer that is driven by truncated constitutively active splice variants of AR that lack the C-terminal ligand-binding domain (LBD).Areas covered: This article presents an overview of the relevance of AR and its intrinsically disordered NTD as a drug target. AR structure and approaches to blocking AR transcriptional activity are discussed. The discovery of small molecules, including the libraries used, proven binders to the AR-NTD, and site of interaction of these small molecules in the AR-NTD are presented along with discussion of the Phase I clinical trial.Expert opinion: The lack of drugs in the clinic that directly bind IDPs/IDRs reflects the difficulty of targeting these proteins and obtaining specificity. However, it may also point to an inappropriateness of too closely borrowing concepts and resources from drug discovery to folded proteins.
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Affiliation(s)
- Marianne D Sadar
- Genome Sciences, BC Cancer and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
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9
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Spirina LV, Kovaleva IV, Usynin EA, Goorbunov AK, Kondakova IV. Progesterone Receptor Expression in the Benign Prostatic Hyperplasia and Prostate Cancer Tissues, Relation with Transcription, Growth Factors, Hormone Reception and Components of the AKT/mTOR Signaling Pathway. Asian Pac J Cancer Prev 2020; 21:423-429. [PMID: 32102520 PMCID: PMC7332139 DOI: 10.31557/apjcp.2020.21.2.423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Indexed: 11/28/2022] Open
Abstract
Background: Progesterone receptor (PR) is a critical regulator in reproductive tissues that controls a variety of cellular processes. The objective of the study was to study the PR expression in patients with benign prostatic hyperplasia and prostate cancers in connection with the transcription, growth factors, AR, ERα, ERβ, and components of the AKT/mTOR signaling pathway expression. Materials and methods: Ninety-seven patients with prostate pathology were enrolled in the study. Forty-two patients had benign prostatic hyperplasia (BH). Fifty-five patients had locally advanced prostate cancer (PCa). The PSA level and the amount of testosterone in the serum were measured using an ELISA assay. The expression level of NF-κB p65, NF-κB p50, HIF-1, HIF-2, growth factor VEGF, VEGFR2, CAIX, as well as AR, ERα, ERβ, PR, Brn-3α, TRIM16 were quantified by RT-PCR. The protein level of Brn-3α, TRIM16 was detected by Western Blotting. Results: Growth in PR expression was observed in PCa tissues compared to BH ones without changes in the clinical and pathological features of the patients. An increase in PR expression was detected in patients with PCa compared to BH. Its mRNA level depended on the expression of AR, Brn-3α, and TRIM16, components of the AKT/mTOR signaling pathway, transcription, and growth factors. An increase in the TRIM16 expression in the PCa tissues was noted in the case of a low PR level. We revealed the growth in PR expression was accompanied by the suppression of the signaling cascade activity, AR, Brn-3α mRNA level, and the enhanced PTEN expression in PCa tissues. The increase in PR expression in PCa led to a decrease in the level of mRNA of NF-κB, HIF-1, VEGF, and VEGFR2. Conclusion: In general, the data indicated the significance of the PR expression in the development of the prostate pathology that affected the cross-talk between the steroid hormone reception and signal transduction.
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Affiliation(s)
- Liudmila V Spirina
- Leader Researcher, Laboratory of Tumor Biochemistry, Tomsk National Research Medical Center, Russian Academy of Medical Sciences, Russian Federation.,Division of Biochemistry and Molecular Biology with Course of Clinical Laboratory Diagnostic; Siberian State Medical University, Russian Federation
| | - Irina V Kovaleva
- Student of Medico-Biological Faculty, Siberian State Medical University, Russian Federation
| | - Evgeny A Usynin
- Department of Surgical, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Medical Sciences, Russian Federation
| | - Alexey K Goorbunov
- Department of Surgical, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Medical Sciences, Russian Federation
| | - Irina V Kondakova
- Leader Researcher, Laboratory of Tumor Biochemistry, Tomsk National Research Medical Center, Russian Academy of Medical Sciences, Russian Federation
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10
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Obst JK, Wang J, Jian K, Williams DE, Tien AH, Mawji N, Tam T, Yang YC, Andersen RJ, Chi KN, Montgomery B, Sadar MD. Revealing Metabolic Liabilities of Ralaniten To Enhance Novel Androgen Receptor Targeted Therapies. ACS Pharmacol Transl Sci 2019; 2:453-467. [PMID: 32259077 PMCID: PMC7088963 DOI: 10.1021/acsptsci.9b00065] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Indexed: 12/15/2022]
Abstract
Inhibition of the androgen receptor (AR) is the mainstay treatment for advanced prostate cancer. Ralaniten (formally EPI-002) prevents AR transcriptional activity by binding to its N-terminal domain (NTD) which is essential for transcriptional activity. Ralaniten acetate (EPI-506) the triacetate pro-drug of ralaniten, remains the only AR-NTD inhibitor to have entered clinical trials (NCT02606123). While well tolerated, the trial was ultimately terminated due to poor pharmacokinetic properties and resulting pill burden. Here we discovered that ralaniten was glucuronidated which resulted in decreased potency. Long-term treatment of prostate cancer cells with ralaniten results in upregulation of UGT2B enzymes with concomitant loss of potency. This has proven to be a useful model with which to facilitate the development of more potent second-generation AR-NTD inhibitors. Glucuronidated metabolites of ralaniten were also detected in the serum of patients in Phase 1 clinical trials. Therefore, we tested an analogue of ralaniten (EPI-045) which was resistant to glucuronidation and demonstrated superiority to ralaniten in our resistant model. These data support that analogues of ralaniten designed to mitigate glucuronidation may optimize clinical responses to AR-NTD inhibitors.
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Affiliation(s)
- Jon K. Obst
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
- Department
of Pathology and Laboratory Medicine, University
of British Columbia, 2211 Westbrook Mall, Vancouver, British Columbia V6T 2B5, Canada
| | - Jun Wang
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Kunzhong Jian
- Departments
of Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, 2306 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - David E. Williams
- Departments
of Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, 2306 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Amy H. Tien
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Nasrin Mawji
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Teresa Tam
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Yu Chi Yang
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Raymond J. Andersen
- Departments
of Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, 2306 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Kim N. Chi
- BC
Cancer Agency, 600 West
10th Avenue, Vancouver, British
Columbia V5Z 4E6, Canada
| | - Bruce Montgomery
- University
of Washington, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Marianne D. Sadar
- Department
of Genome Sciences Centre, BC Cancer Research
Centre, 675 W 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
- Department
of Pathology and Laboratory Medicine, University
of British Columbia, 2211 Westbrook Mall, Vancouver, British Columbia V6T 2B5, Canada
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11
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Stelloo S, Bergman AM, Zwart W. Androgen receptor enhancer usage and the chromatin regulatory landscape in human prostate cancers. Endocr Relat Cancer 2019; 26:R267-R285. [PMID: 30865928 DOI: 10.1530/erc-19-0032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/13/2019] [Indexed: 12/12/2022]
Abstract
The androgen receptor (AR) is commonly known as a key transcription factor in prostate cancer development, progression and therapy resistance. Genome-wide chromatin association studies revealed that transcriptional regulation by AR mainly depends on binding to distal regulatory enhancer elements that control gene expression through chromatin looping to gene promoters. Changes in the chromatin epigenetic landscape and DNA sequence can locally alter AR-DNA-binding capacity and consequently impact transcriptional output and disease outcome. The vast majority of reports describing AR chromatin interactions have been limited to cell lines, identifying numerous other factors and interacting transcription factors that impact AR chromatin interactions. Do these factors also impact AR cistromics - the genome-wide chromatin-binding landscape of AR - in vivo? Recent technological advances now enable researchers to identify AR chromatin-binding sites and their target genes in human specimens. In this review, we provide an overview of the different factors that influence AR chromatin binding in prostate cancer specimens, which is complemented with knowledge from cell line studies. Finally, we discuss novel perspectives on studying AR cistromics in clinical samples.
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Affiliation(s)
- Suzan Stelloo
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Andries M Bergman
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Division of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Wilbert Zwart
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Department of Biomedical Engineering, Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
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12
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Li D, Zhou W, Pang J, Tang Q, Zhong B, Shen C, Xiao L, Hou T. A magic drug target: Androgen receptor. Med Res Rev 2018; 39:1485-1514. [PMID: 30569509 DOI: 10.1002/med.21558] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/20/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Androgen receptor (AR) is closely associated with a group of hormone-related diseases including the cancers of prostate, breast, ovary, pancreas, etc and anabolic deficiencies such as muscle atrophy and osteoporosis. Depending on the specific type and stage of the diseases, AR ligands including not only antagonists but also agonists and modulators are considered as potential therapeutics, which makes AR an extremely interesting drug target. Here, we at first review the current understandings on the structural characteristics of AR, and then address why and how AR is investigated as a drug target for the relevant diseases and summarize the representative antagonists and agonists targeting five prospective small molecule binding sites at AR, including ligand-binding pocket, activation function-2 site, binding function-3 site, DNA-binding domain, and N-terminal domain, providing recent insights from a target and drug development view. Further comprehensive studies on AR and AR ligands would bring fruitful information and push the therapy of AR relevant diseases forward.
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Affiliation(s)
- Dan Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wenfang Zhou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China.,State Key Lab of CAD&CG, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jinping Pang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qin Tang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Bingling Zhong
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chao Shen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Li Xiao
- School of Life Science, Huzhou University, Huzhou, China
| | - Tingjun Hou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China.,State Key Lab of CAD&CG, Zhejiang University, Hangzhou, Zhejiang, China
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13
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Centenera MM, Selth LA, Ebrahimie E, Butler LM, Tilley WD. New Opportunities for Targeting the Androgen Receptor in Prostate Cancer. Cold Spring Harb Perspect Med 2018; 8:a030478. [PMID: 29530945 PMCID: PMC6280715 DOI: 10.1101/cshperspect.a030478] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recent genomic analyses of metastatic prostate cancer have provided important insight into adaptive changes in androgen receptor (AR) signaling that underpin resistance to androgen deprivation therapies. Novel strategies are required to circumvent these AR-mediated resistance mechanisms and thereby improve prostate cancer survival. In this review, we present a summary of AR structure and function and discuss mechanisms of AR-mediated therapy resistance that represent important areas of focus for the development of new therapies.
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Affiliation(s)
- Margaret M Centenera
- Adelaide Medical School and Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide SA 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide SA 5001, Australia
| | - Luke A Selth
- Adelaide Medical School and Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide SA 5005, Australia
- Dame Roma Mitchell Cancer Research Laboratories, Adelaide Medical School, University of Adelaide, Adelaide SA 5005, Australia
| | - Esmaeil Ebrahimie
- Dame Roma Mitchell Cancer Research Laboratories, Adelaide Medical School, University of Adelaide, Adelaide SA 5005, Australia
| | - Lisa M Butler
- Adelaide Medical School and Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide SA 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide SA 5001, Australia
| | - Wayne D Tilley
- Adelaide Medical School and Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide SA 5005, Australia
- Dame Roma Mitchell Cancer Research Laboratories, Adelaide Medical School, University of Adelaide, Adelaide SA 5005, Australia
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14
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Goicochea NL, Garnovskaya M, Blanton MG, Chan G, Weisbart R, Lilly MB. Development of cell-penetrating bispecific antibodies targeting the N-terminal domain of androgen receptor for prostate cancer therapy†. Protein Eng Des Sel 2017; 30:785-793. [DOI: 10.1093/protein/gzx058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Nancy L Goicochea
- Department of Medicine, Division of Hematology/Oncology, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
| | - Maria Garnovskaya
- Department of Medicine, Division of Hematology/Oncology, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
| | - Mary G Blanton
- Department of Medicine, Division of Hematology/Oncology, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
| | - Grace Chan
- Veterans Affairs Greater Los Angeles Health Care System, 16111 Plummer St., Sepulveda, CA 91343, USA
| | - Richard Weisbart
- Veterans Affairs Greater Los Angeles Health Care System, 16111 Plummer St., Sepulveda, CA 91343, USA
| | - Michael B Lilly
- Department of Medicine, Division of Hematology/Oncology, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
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15
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Myung JK, Wang G, Chiu HHL, Wang J, Mawji NR, Sadar MD. Inhibition of androgen receptor by decoy molecules delays progression to castration-recurrent prostate cancer. PLoS One 2017; 12:e0174134. [PMID: 28306720 PMCID: PMC5357013 DOI: 10.1371/journal.pone.0174134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/23/2017] [Indexed: 12/20/2022] Open
Abstract
Androgen receptor (AR) is a member of the steroid receptor family and a therapeutic target for all stages of prostate cancer. AR is activated by ligand binding within its C-terminus ligand-binding domain (LBD). Here we show that overexpression of the AR NTD to generate decoy molecules inhibited both the growth and progression of prostate cancer in castrated hosts. Specifically, it was shown that lentivirus delivery of decoys delayed hormonal progression in castrated hosts as indicated by increased doubling time of tumor volume, prolonged time to achieve pre-castrate levels of serum prostate-specific antigen (PSA) and PSA nadir. These clinical parameters are indicative of delayed hormonal progression and improved therapeutic response and prognosis. Decoys reduced the expression of androgen-regulated genes that correlated with reduced in situ interaction of the AR with androgen response elements. Decoys did not reduce levels of AR protein or prevent nuclear localization of the AR. Nor did decoys interact directly with the AR. Thus decoys did not inhibit AR transactivation by a dominant negative mechanism. This work provides evidence that the AR NTD plays an important role in the hormonal progression of prostate cancer and supports the development of AR antagonists that target the AR NTD.
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Affiliation(s)
- Jae-Kyung Myung
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Gang Wang
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Helen H. L. Chiu
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Jun Wang
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Nasrin R. Mawji
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Marianne D. Sadar
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- * E-mail:
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16
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Monaghan AE, McEwan IJ. A sting in the tail: the N-terminal domain of the androgen receptor as a drug target. Asian J Androl 2017; 18:687-94. [PMID: 27212126 PMCID: PMC5000789 DOI: 10.4103/1008-682x.181081] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The role of androgen receptor (AR) in the initiation and progression of prostate cancer (PCa) is well established. Competitive inhibition of the AR ligand-binding domain (LBD) has been the staple of antiandrogen therapies employed to combat the disease in recent years. However, their efficacy has often been limited by the emergence of resistance, mediated through point mutations, and receptor truncations. As a result, the prognosis for patients with malignant castrate resistant disease remains poor. The amino-terminal domain (NTD) of the AR has been shown to be critical for AR function. Its modular activation function (AF-1) is important for both gene regulation and participation in protein-protein interactions. However, due to the intrinsically disordered structure of the domain, its potential as a candidate for therapeutic intervention has been dismissed in the past. The recent emergence of the small molecule EPI-001 has provided evidence that AR-NTD can be targeted therapeutically, independent of the LBD. Targeting of AR-NTD has the potential to disrupt multiple intermolecular interactions between AR and its coregulatory binding partners, in addition to intramolecular cross-talk between the domains of the AR. Therapeutics targeting these protein-protein interactions or NTD directly should also have efficacy against emerging AR splice variants which may play a role in PCa progression. This review will discuss the role of intrinsic disorder in AR function and illustrate how emerging therapies might target NTD in PCa.
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Affiliation(s)
- Amy E Monaghan
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
| | - Iain J McEwan
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
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17
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Russo A, Manna SL, Novellino E, Malfitano AM, Marasco D. Molecular signaling involving intrinsically disordered proteins in prostate cancer. Asian J Androl 2017; 18:673-81. [PMID: 27212129 PMCID: PMC5000787 DOI: 10.4103/1008-682x.181817] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Investigations on cellular protein interaction networks (PINs) reveal that proteins that constitute hubs in a PIN are notably enriched in Intrinsically Disordered Proteins (IDPs) compared to proteins that constitute edges, highlighting the role of IDPs in signaling pathways. Most IDPs rapidly undergo disorder-to-order transitions upon binding to their biological targets to perform their function. Conformational dynamics enables IDPs to be versatile and to interact with a broad range of interactors under normal physiological conditions where their expression is tightly modulated. IDPs are involved in many cellular processes such as cellular signaling, transcriptional regulation, and splicing; thus, their high-specificity/low-affinity interactions play crucial roles in many human diseases including cancer. Prostate cancer (PCa) is one of the leading causes of cancer-related mortality in men worldwide. Therefore, identifying molecular mechanisms of the oncogenic signaling pathways that are involved in prostate carcinogenesis is crucial. In this review, we focus on the aspects of cellular pathways leading to PCa in which IDPs exert a primary role.
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Affiliation(s)
- Anna Russo
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134 Naples, Italy
| | - Sara La Manna
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134 Naples, Italy
| | - Ettore Novellino
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134 Naples, Italy
| | - Anna Maria Malfitano
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134 Naples, Italy
| | - Daniela Marasco
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134 Naples, Italy
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18
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Azoitei A, Merseburger AS, Godau B, Hoda MR, Schmid E, Cronauer MV. C-terminally truncated constitutively active androgen receptor variants and their biologic and clinical significance in castration-resistant prostate cancer. J Steroid Biochem Mol Biol 2017; 166:38-44. [PMID: 27345700 DOI: 10.1016/j.jsbmb.2016.06.008] [Citation(s) in RCA: 13] [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] [Received: 02/05/2016] [Revised: 06/10/2016] [Accepted: 06/20/2016] [Indexed: 10/21/2022]
Abstract
A mechanism allowing castration resistant prostate cancer cells to escape the effects of conventional anti-hormonal treatments is the synthesis of constitutively active, C-terminally truncated androgen receptor (AR)-variants. Lacking the entire or vast parts of the ligand binding domain, the intended target of traditional endocrine therapies, these AR-variants (termed ARΔLBD) are insensitive to all traditional treatments including second generation compounds like abiraterone, enzalutamide or ARN-509. Although ARΔLBD are predominantly products of alternative splicing, they can also be products of nonsense mutations or proteolytic cleavage. In this review, we will discuss the etiology and function of c-terminally truncated AR-variants and their clinical significance as markers/targets for the treatment of castration resistant prostate cancer.
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Affiliation(s)
- Anca Azoitei
- Department of Urology, Ulm University Medical School, 89075 Ulm, Germany
| | - Axel S Merseburger
- Department of Urology, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Beate Godau
- Department of Urology, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - M Raschid Hoda
- Department of Urology, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Evi Schmid
- Department of Pediatric Surgery and Pediatric Urology, University Hospital Tübingen, 72076 Tübingen, Germany
| | - Marcus V Cronauer
- Department of Urology, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany.
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19
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De Mol E, Fenwick RB, Phang CTW, Buzón V, Szulc E, de la Fuente A, Escobedo A, García J, Bertoncini CW, Estébanez-Perpiñá E, McEwan IJ, Riera A, Salvatella X. EPI-001, A Compound Active against Castration-Resistant Prostate Cancer, Targets Transactivation Unit 5 of the Androgen Receptor. ACS Chem Biol 2016; 11:2499-505. [PMID: 27356095 DOI: 10.1021/acschembio.6b00182] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Castration-resistant prostate cancer is the lethal condition suffered by prostate cancer patients that become refractory to androgen deprivation therapy. EPI-001 is a recently identified compound active against this condition that modulates the activity of the androgen receptor, a nuclear receptor that is essential for disease progression. The mechanism by which this compound exerts its inhibitory activity is however not yet fully understood. Here we show, by using high resolution solution nuclear magnetic resonance spectroscopy, that EPI-001 selectively interacts with a partially folded region of the transactivation domain of the androgen receptor, known as transactivation unit 5, that is key for the ability of prostate cells to proliferate in the absence of androgens, a distinctive feature of castration-resistant prostate cancer. Our results can contribute to the development of more potent and less toxic novel androgen receptor antagonists for treating this disease.
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Affiliation(s)
- Eva De Mol
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - R. Bryn Fenwick
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Christopher T. W. Phang
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Victor Buzón
- Departament
de Bioquímica i Biología Molecular, and Institute of
Biomedicine, University of Barcelona (IBUB), Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Elzbieta Szulc
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Alex de la Fuente
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Albert Escobedo
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Jesús García
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Carlos W. Bertoncini
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Eva Estébanez-Perpiñá
- Departament
de Bioquímica i Biología Molecular, and Institute of
Biomedicine, University of Barcelona (IBUB), Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Iain J. McEwan
- Institute
of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, IMS Building, Foresterhill, Aberdeen AB25 2ZD, Scotland, United Kingdom
| | - Antoni Riera
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
- Departament
de Química Orgànica, Universitat de Barcelona, Martí
i Franqués 1-11, 08028 Barcelona, Spain
| | - Xavier Salvatella
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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20
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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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21
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Shukla GC, Plaga AR, Shankar E, Gupta S. Androgen receptor-related diseases: what do we know? Andrology 2016; 4:366-81. [PMID: 26991422 DOI: 10.1111/andr.12167] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/28/2015] [Accepted: 01/06/2016] [Indexed: 01/09/2023]
Abstract
The androgen receptor (AR) and the androgen-AR signaling pathway play a significant role in male sexual differentiation and the development and function of male reproductive and non-reproductive organs. Because of AR's widely varied and important roles, its abnormalities have been identified in various diseases such as androgen insensitivity syndrome, spinal bulbar muscular atrophy, benign prostatic hyperplasia, and prostate cancer. This review provides an overview of the function of androgens and androgen-AR mediated diseases. In addition, the diseases delineated above are discussed with respect to their association with mutations and other post-transcriptional modifications in the AR. Finally, we present an introduction to the potential therapeutic application of most recent pharmaceuticals including miRNAs in prostate cancer that specifically target the transactivation function of the AR at post-transcriptional stages.
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Affiliation(s)
- G C Shukla
- Center of Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH, USA.,Department of Biological Sciences, Cleveland State University, Cleveland, OH, USA
| | - A R Plaga
- Center of Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH, USA.,Department of Biological Sciences, Cleveland State University, Cleveland, OH, USA
| | - E Shankar
- Department of Urology, Case Western Reserve University & University Hospitals Case Medical Center, Cleveland, OH, USA
| | - S Gupta
- Department of Urology, Case Western Reserve University & University Hospitals Case Medical Center, Cleveland, OH, USA.,Department of Nutrition, Case Western Reserve University, Cleveland, OH, USA.,Division of General Medical Sciences, Case Comprehensive Cancer Center, Cleveland, OH, USA.,Department of Urology, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA
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22
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Kato M, Banuelos CA, Imamura Y, Leung JK, Caley DP, Wang J, Mawji NR, Sadar MD. Cotargeting Androgen Receptor Splice Variants and mTOR Signaling Pathway for the Treatment of Castration-Resistant Prostate Cancer. Clin Cancer Res 2015; 22:2744-54. [PMID: 26712685 DOI: 10.1158/1078-0432.ccr-15-2119] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 12/13/2015] [Indexed: 11/16/2022]
Abstract
PURPOSE The PI3K/Akt/mTOR pathway is activated in most castration-resistant prostate cancers (CRPC). Transcriptionally active androgen receptor (AR) plays a role in the majority of CRPCs. Therefore, cotargeting full-length (FL) AR and PI3K/Akt/mTOR signaling has been proposed as a possible, more effective therapeutic approach for CRPC. However, truncated AR-splice variants (AR-V) that are constitutively active and dominant over FL-AR are associated with tumor progression and resistance mechanisms in CRPC. It is currently unknown how blocking the PI3K/Akt/mTOR pathway impacts prostate cancer driven by AR-Vs. Here, we evaluated the efficacy and mechanism of combination therapy to block mTOR activity together with EPI-002, an AR N-terminal domain (NTD) antagonist that blocks the transcriptional activities of FL-AR and AR-Vs in models of CRPC. EXPERIMENTAL DESIGN To determine the functional roles of FL-AR, AR-Vs, and PI3K/Akt/mTOR pathways, we employed EPI-002 or enzalutamide and BEZ235 (low dose) or everolimus in human prostate cancer cells that express FL-AR or FL-AR and AR-Vs (LNCaP95). Gene expression and efficacy were examined in vitro and in vivo RESULTS EPI-002 had antitumor activity in enzalutamide-resistant LNCaP95 cells that was associated with decreased expression of AR-V target genes (e.g., UBE2C). Inhibition of mTOR provided additional blockade of UBE2C expression. A combination of EPI-002 and BEZ235 decreased the growth of LNCaP95 cells in vitro and in vivo CONCLUSIONS Cotargeting mTOR and AR-NTD to block transcriptional activities of FL-AR and AR-Vs provided maximum antitumor efficacy in PTEN-null, enzalutamide-resistant CRPC. Clin Cancer Res; 22(11); 2744-54. ©2015 AACR.
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Affiliation(s)
- Minoru Kato
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Carmen A Banuelos
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Yusuke Imamura
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Jacky K Leung
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Daniel P Caley
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Jun Wang
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Nasrin R Mawji
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Marianne D Sadar
- Department of Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.
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23
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Androgen receptor: structure, role in prostate cancer and drug discovery. Acta Pharmacol Sin 2015; 36:3-23. [PMID: 24909511 PMCID: PMC4571323 DOI: 10.1038/aps.2014.18] [Citation(s) in RCA: 536] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/05/2014] [Indexed: 12/15/2022] Open
Abstract
Androgens and androgen receptors (AR) play a pivotal role in expression of the male phenotype. Several diseases, such as androgen insensitivity syndrome (AIS) and prostate cancer, are associated with alterations in AR functions. Indeed, androgen blockade by drugs that prevent the production of androgens and/or block the action of the AR inhibits prostate cancer growth. However, resistance to these drugs often occurs after 2–3 years as the patients develop castration-resistant prostate cancer (CRPC). In CRPC, a functional AR remains a key regulator. Early studies focused on the functional domains of the AR and its crucial role in the pathology. The elucidation of the structures of the AR DNA binding domain (DBD) and ligand binding domain (LBD) provides a new framework for understanding the functions of this receptor and leads to the development of rational drug design for the treatment of prostate cancer. An overview of androgen receptor structure and activity, its actions in prostate cancer, and how structural information and high-throughput screening have been or can be used for drug discovery are provided herein.
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24
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Banuelos CA, Lal A, Tien AH, Shah N, Yang YC, Mawji NR, Meimetis LG, Park J, Kunzhong J, Andersen RJ, Sadar MD. Characterization of niphatenones that inhibit androgen receptor N-terminal domain. PLoS One 2014; 9:e107991. [PMID: 25268119 PMCID: PMC4182434 DOI: 10.1371/journal.pone.0107991] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/18/2014] [Indexed: 01/24/2023] Open
Abstract
Androgen ablation therapy causes a temporary reduction in tumor burden in patients with advanced prostate cancer. Unfortunately the malignancy will return to form lethal castration-recurrent prostate cancer (CRPC). The androgen receptor (AR) remains transcriptionally active in CRPC in spite of castrate levels of androgens in the blood. AR transcriptional activity resides in its N-terminal domain (NTD). Possible mechanisms of continued AR transcriptional activity may include, at least in part, expression of constitutively active splice variants of AR that lack the C-terminal ligand-binding domain (LBD). Current therapies that target the AR LBD, would not be effective against these AR variants. Currently no drugs are clinically available that target the AR NTD which should be effective against these AR variants as well as full-length AR. Niphatenones were originally isolated and identified in active extracts from Niphates digitalis marine sponge. Here we begin to characterize the mechanism of niphatenones in blocking AR transcriptional activity. Both enantiomers had similar IC50 values of 6 µM for inhibiting the full-length AR in a functional transcriptional assay. However, (S)-niphatenone had significantly better activity against the AR NTD compared to (R)-niphatenone. Consistent with niphatenones binding to and inhibiting transactivation of AR NTD, niphatenones inhibited AR splice variant. Niphatenone did not affect the transcriptional activity of the related progesterone receptor, but slightly decreased glucocorticoid receptor (GR) activity and covalently bound to GR activation function-1 (AF-1) region. Niphatenone blocked N/C interactions of AR without altering either AR protein levels or its intracellular localization in response to androgen. Alkylation with glutathione suggests that niphatenones are not a feasible scaffold for further drug development.
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Affiliation(s)
- Carmen A. Banuelos
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Aaron Lal
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Amy H. Tien
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Neel Shah
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Yu Chi Yang
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Nasrin R. Mawji
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Labros G. Meimetis
- Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jacob Park
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Jian Kunzhong
- Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Raymond J. Andersen
- Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marianne D. Sadar
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- * E-mail:
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Liu HH, Tsai YS, Lai CL, Tang CH, Lai CH, Wu HC, Hsieh JT, Yang CR. Evolving Personalized Therapy for Castration-Resistant Prostate Cancer. Biomedicine (Taipei) 2014; 4:2. [PMID: 25520915 PMCID: PMC4264971 DOI: 10.7603/s40681-014-0002-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 12/31/2013] [Indexed: 12/21/2022] Open
Abstract
With advances in molecular biologic and genomic technology, detailed molecular mechanisms for development of castration-resistant prostate cancer (CRPC) have surfaced. Metastatic prostate cancer (PCa) no longer represents an end stage, with many emerging therapeutic agents approved as effective in prolonging survival of patients from either pre- or post-docetaxel stage. Given tumor heterogeneity in patients, a one-size-fits-all theory for curative therapy remains questionable. With the support of evidence from continuing clinical trials, each treatment modality has gradually been found suitable for selective best-fit patients: e.g., new androgen synthesis inhibitor arbiraterone, androgen receptor signaling inhibitor enzalutamide, sipuleucel-T immunotherapy, new taxane carbazitaxel, calcium-mimetic radium-223 radiopharmaceutical agent. Moreover, several emerging immunomodulating agents and circulating tumor cell enumeration and analysis showed promise in animal or early phase clinical trials. While the era of personalized therapy for CRPC patients is still in infancy, optimal therapeutic agents and their sequencing loom not far in the future.
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Affiliation(s)
- Hsin-Ho Liu
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Division of Urology, Department of Surgery, Taichung Tzu Chi General Hospital, Taichung, Taiwan
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei, Taiwan
| | - Yuh-Shyan Tsai
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Urology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Chen-Li Lai
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Urology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Chih-Hsin Tang
- School of Medicine, China Medical University, Tainan, Taiwan
| | - Chih-Ho Lai
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- School of Medicine, China Medical University, Tainan, Taiwan
| | - Hsi-Chin Wu
- School of Medicine, China Medical University, Tainan, Taiwan
- Department of Urology, China Medical University Hospital, Tainan, Taiwan
| | - Jer-Tsong Hsieh
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Graduate Institute of Cancer Biology, China Medical University, Tainan, Taiwan
| | - Che-Rei Yang
- School of Medicine, China Medical University, Tainan, Taiwan
- Department of Urology, China Medical University Hospital, Tainan, Taiwan
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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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McCarty MF, Hejazi J, Rastmanesh R. Beyond androgen deprivation: ancillary integrative strategies for targeting the androgen receptor addiction of prostate cancer. Integr Cancer Ther 2014; 13:386-95. [PMID: 24867960 DOI: 10.1177/1534735414534728] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The large majority of clinical prostate cancers remain dependent on androgen receptor (AR) activity for proliferation even as they lose their responsiveness to androgen deprivation or antagonism. AR activity can be maintained in these circumstances by increased AR synthesis--often reflecting increased NF-κB activation; upregulation of signaling pathways that promote AR activity in the absence of androgens; and by emergence of AR mutations or splice variants lacking the ligand-binding domain, which render the AR constitutively active. Drugs targeting the N-terminal transactivating domain of the AR, some of which are now in preclinical development, can be expected to inhibit the activity not only of unmutated ARs but also of the mutant forms and splice variants selected for by androgen deprivation. Concurrent measures that suppress AR synthesis or boost AR turnover could be expected to complement the efficacy of such drugs. A number of nutraceuticals that show efficacy in prostate cancer xenograft models--including polyphenols from pomegranate, grape seed, and green tea, the crucifera metabolite diindolylmethane, and the hormone melatonin--have the potential to suppress AR synthesis via downregulation of NF-κB activity; clinical doses of salicylate may have analogous efficacy. The proteasomal turnover of the AR is abetted by diets with a high ratio of long-chain omega-3 to omega-6 fatty acids, which are beneficial in prostate cancer xenograft models; berberine and sulforaphane, by inhibiting AR's interaction with its chaperone Hsp90, likewise promote AR proteasomal degradation and retard growth of human prostate cancer in nude mice. Hinge region acetylation of the AR is required for optimal transactivational activity, and low micromolar concentrations of the catechin epigallocatechin-3-gallate (EGCG) can inhibit such acetylation--possibly explaining the ability of EGCG administration to suppress androgenic activity and cell proliferation in prostate cancer xenografts. Hence, it is proposed that regimens featuring an N-terminal domain-targeting drug, various nutraceuticals/drugs that downregulate NF-κB activity, and/or supplemental intakes of fish oil, berberine, sulforaphane, and EGCG have potential for blocking proliferation of prostate cancer by targeting its characteristic addiction to androgen receptor activity.
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Affiliation(s)
| | - Jalal Hejazi
- Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Rastmanesh
- National Nutrition and Food Sciences Technology Research Institute, Tehran, Iran
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Experimental evidence of persistent androgen-receptor-dependency in castration-resistant prostate cancer. Int J Mol Sci 2013; 14:15615-35. [PMID: 23896594 PMCID: PMC3759876 DOI: 10.3390/ijms140815615] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 07/14/2013] [Accepted: 07/15/2013] [Indexed: 01/08/2023] Open
Abstract
In the majority of castration-resistant prostate cancer (CRPC), prostate-specific antigen (PSA), product of a gene that is almost exclusively regulated by the androgen receptor (AR), still acts as a serum marker reflecting disease burden, indicating that AR signaling is activated even under castrate level of serum androgen. Accumulated evidence shows that transcriptional ability of AR is activated both in ligand-dependent and -independent manners in CRPC cells. Some androgen-independent sublines derived from originally androgen-dependent LNCaP prostate cancer cells overexpress the AR and PSA, for which silencing the AR gene suppresses cellular proliferation. The overexpression of the AR confers androgen-independent growth ability on androgen-dependent prostate cancer cells. Some patient-derived prostate cancer xenograft lines also acquire castration-resistant growth ability secreting PSA. More recent publications have shown that the AR activated in CRPC cells regulates distinct gene sets from that in androgen-dependent status. This concept provides very important insights in the development of novel anti-prostate cancer drugs such as new generation anti-androgens and CYP17 inhibitors.
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Lallous N, Dalal K, Cherkasov A, Rennie PS. Targeting alternative sites on the androgen receptor to treat castration-resistant prostate cancer. Int J Mol Sci 2013; 14:12496-519. [PMID: 23771019 PMCID: PMC3709796 DOI: 10.3390/ijms140612496] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 05/29/2013] [Accepted: 06/03/2013] [Indexed: 01/22/2023] Open
Abstract
Recurrent, metastatic prostate cancer continues to be a leading cause of cancer-death in men. The androgen receptor (AR) is a modular, ligand-inducible transcription factor that regulates the expression of genes that can drive the progression of this disease, and as a consequence, this receptor is a key therapeutic target for controlling prostate cancer. The current drugs designed to directly inhibit the AR are called anti-androgens, and all act by competing with androgens for binding to the androgen/ligand binding site. Unfortunately, with the inevitable progression of the cancer to castration resistance, many of these drugs become ineffective. However, there are numerous other regulatory sites on this protein that have not been exploited therapeutically. The regulation of AR activity involves a cascade of complex interactions with numerous chaperones, co-factors and co-regulatory proteins, leading ultimately to direct binding of AR dimers to specific DNA androgen response elements within the promoter and enhancers of androgen-regulated genes. As part of the family of nuclear receptors, the AR is organized into modular structural and functional domains with specialized roles in facilitating their inter-molecular interactions. These regions of the AR present attractive, yet largely unexploited, drug target sites for reducing or eliminating androgen signaling in prostate cancers. The design of small molecule inhibitors targeting these specific AR domains is only now being realized and is the culmination of decades of work, including crystallographic and biochemistry approaches to map the shape and accessibility of the AR surfaces and cavities. Here, we review the structure of the AR protein and describe recent advancements in inhibiting its activity with small molecules specifically designed to target areas distinct from the receptor’s androgen binding site. It is anticipated that these new classes of anti-AR drugs will provide an additional arsenal to treat castration-resistant prostate cancer.
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Affiliation(s)
- Nada Lallous
- Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.
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30
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Myung JK, Banuelos CA, Fernandez JG, Mawji NR, Wang J, Tien AH, Yang YC, Tavakoli I, Haile S, Watt K, McEwan IJ, Plymate S, Andersen RJ, Sadar MD. An androgen receptor N-terminal domain antagonist for treating prostate cancer. J Clin Invest 2013; 123:2948-60. [PMID: 23722902 DOI: 10.1172/jci66398] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 03/28/2013] [Indexed: 12/27/2022] Open
Abstract
Hormone therapies for advanced prostate cancer target the androgen receptor (AR) ligand-binding domain (LBD), but these ultimately fail and the disease progresses to lethal castration-resistant prostate cancer (CRPC). The mechanisms that drive CRPC are incompletely understood, but may involve constitutively active AR splice variants that lack the LBD. The AR N-terminal domain (NTD) is essential for AR activity, but targeting this domain with small-molecule inhibitors is complicated by its intrinsic disorder. Here we investigated EPI-001, a small-molecule antagonist of AR NTD that inhibits protein-protein interactions necessary for AR transcriptional activity. We found that EPI analogs covalently bound the NTD to block transcriptional activity of AR and its splice variants and reduced the growth of CRPC xenografts. These findings suggest that the development of small-molecule inhibitors that bind covalently to intrinsically disordered proteins is a promising strategy for development of specific and effective anticancer agents.
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Affiliation(s)
- Jae-Kyung Myung
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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Abstract
Androgenic steroids are important for male development in utero and secondary sexual characteristics at puberty. In addition, androgens play a role in non-reproductive tissues, such as bone and muscle in both sexes. The actions of the androgens testosterone and dihydrotestosterone are mediated by a single receptor protein, the androgen receptor. Over the last 60–70 years there has been considerable research interest in the development of inhibitors of androgen receptor for the management of diseases such as prostate cancer. However, more recently, there is also a growing appreciation of the need for selective androgen modulators that would demonstrate tissue-selective agonist or antagonist activity. The chemistry and biology of selective agonists, antagonists and selective androgen receptor modulators will be discussed in this review.
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Lonergan PE, Tindall DJ. Truncated Androgen Receptor Splice Variants in Prostate Cancer. Prostate Cancer 2013. [DOI: 10.1007/978-1-4614-6828-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Sheikh H, Abdulghani J, Ali S, Sinha R, Lipton A. Impact of Genetic Targets on Prostate Cancer Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 779:359-83. [DOI: 10.1007/978-1-4614-6176-0_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Targeted disruption of the p160 coactivator interface of androgen receptor (AR) selectively inhibits AR activity in both androgen-dependent and castration-resistant AR-expressing prostate cancer cells. Int J Biochem Cell Biol 2012; 45:763-72. [PMID: 23270728 DOI: 10.1016/j.biocel.2012.12.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 11/24/2012] [Accepted: 12/13/2012] [Indexed: 10/27/2022]
Abstract
The evidence that androgen blockade-resistant prostate cancer, termed castration resistant, remains androgen receptor (AR) dependent is compelling. AR is re-activated through multiple mechanisms including expression of constitutively active splice variants that lack hormone binding domains (HBDs). This highlights the need to develop therapies that target regions other than the HBD. Because the p160 coactivators interact most strongly with the amino-terminus of AR, we examined the consequences of disrupting this interaction. We identified two overlapping SRC-1 peptides that interact with AR, but not with progesterone receptor. These peptides reduce AR and AR variant AR-V7 dependent induction of an AR responsive reporter. Using mammalian two hybrid assays, we found that the peptides interrupt the AR/SRC-1, AR/SRC-2 and AR N/C interactions, but not SRC-1/CARM-1 interactions. Consistent with the SRC-1 dependence of induced, but not repressed genes, in LNCaP cells, the peptides inhibited hormone dependent induction of endogenous target genes including PSA and TMPRSS2, but did not block AR dependent repression of UGT2B17 or inhibit vitamin D receptor activity. Simultaneous detection of SRC-1 peptides and PSA by double immunofluorescence in transfected LNCaP cells clearly demonstrated a strong reduction in PSA levels in cells expressing the peptides. The peptides also inhibited the AR dependent expression of PSA in castration resistant C4-2 cells. Moreover they inhibited androgen dependent proliferation of LNCaP cells and proliferation of C4-2 cells in androgen depleted medium without affecting AR negative PC-3 cells. Thus, the p160 coactivator binding site is a novel potential therapeutic target to inhibit AR activity.
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35
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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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36
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Abstract
Nuclear receptor (NR)-targeted therapies comprise a large class of clinically employed drugs. A number of drugs currently being used against this protein class were designed as structural analogs of the endogenous ligand of these receptors. In recent years, there has been significant interest in developing newer strategies to target NRs, especially those that rely on mechanistic pathways of NR function. Prominent among these are noncanonical means of targeting NRs, which include selective NR modulation, NR coactivator interaction inhibition, inhibition of NR DNA binding, modulation of NR cellular localization, modulation of NR ligand biosynthesis and downregulation of NR levels in target tissues. This article reviews each of these promising emerging strategies for NR drug development and highlights some of most significant successes achieved in using them.
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Mohler ML, Coss CC, Duke CB, Patil SA, Miller DD, Dalton JT. Androgen receptor antagonists: a patent review (2008-2011). Expert Opin Ther Pat 2012; 22:541-65. [PMID: 22583332 DOI: 10.1517/13543776.2012.682571] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Androgen receptor (AR) antagonists are predominantly used as chemical castration to treat prostate cancer (i.e., in conjunction with androgen deprivation therapy (ADT)). Unfortunately, castration-resistant prostate cancer (CRPC) typically develops that is refractory to targeted therapy. Insights into CRPC biology have led to the emergence of a promising clinical candidate MDV3100 (1) and a resurgence in this field. A pipeline of preclinical competitive (C-terminally directed) antagonists was discovered using a variety of innovative screening paradigms. Some inhibit nuclear translocation, selectively downregulate or degrade AR (SARD), antagonize wild-type and escape mutant AR (pan-antagonists) and/or antagonize AR target organs in vivo. Separately, the N-terminal domain has emerged as a promising novel target for noncompetitive antagonists. AREAS COVERED AR antagonists whose patents published between 2008 and 2011 are reviewed. Antagonists are organized based on the screening paradigm reported as discussed above. EXPERT OPINION Novel mechanisms provide a more informed basis for selecting a competitive antagonist; however, high potency and favorable in vivo properties remain paramount. Noncompetitive antagonists have theoretical advantages suggestive of improved clinical efficacy, but no clinical proof of concept as of yet.
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Affiliation(s)
- Michael L Mohler
- Preclinical Research and Development, GTx, Inc., 3 North Dunlap Street, Memphis, TN 38163, USA
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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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Meimetis LG, Williams DE, Mawji NR, Banuelos CA, Lal AA, Park JJ, Tien AH, Fernandez JG, de Voogd NJ, Sadar MD, Andersen RJ. Niphatenones, glycerol ethers from the sponge Niphates digitalis block androgen receptor transcriptional activity in prostate cancer cells: structure elucidation, synthesis, and biological activity. J Med Chem 2011; 55:503-14. [PMID: 22148427 DOI: 10.1021/jm2014056] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extracts of the marine sponge Niphates digitalis collected in Dominica showed strong activity in a cell-based assay designed to detect antagonists of the androgen receptor (AR) that could act as lead compounds for the development of a new class of drugs to treat castration recurrent prostate cancer (CRPC). Assay-guided fractionation showed that niphatenones A (3) and B (4), two new glycerol ether lipids, were the active components of the extracts. The structures of 3 and 4 were elucidated by analysis of NMR and MS data and confimed via total synthesis. Biological evaluation of synthetic analogues of the niphatenones has shown that the enantiomers 7 and 8 are more potent than the natural products in the screening assay and defined preliminary SAR for the new AR antagonist pharmacophore, including the finding that the Michael acceptor enone functionality is not required for activity. Niphatenone B (4) and its enantiomer 8 blocked androgen-induced proliferation of LNCaP prostate cancer cells but had no effect on the proliferation of PC3 prostate cancer cells that do not express functional AR, consistent with activity as AR antagonists. Use of the propargyl ether 44 and Click chemistry showed that niphatenone B binds covalently to the activation function-1 (AF1) region of the AR N-terminus domain (NTD).
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Affiliation(s)
- Labros G Meimetis
- Department of Chemistry and Earth, University of British Columbia, 2036 Main Mall, Vancouver, B.C., Canada V6T 1Z1
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40
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New insights into the androgen-targeted therapies and epigenetic therapies in prostate cancer. Prostate Cancer 2011; 2011:918707. [PMID: 22111003 PMCID: PMC3196248 DOI: 10.1155/2011/918707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 07/27/2011] [Indexed: 11/23/2022] Open
Abstract
Prostate cancer is the most common cancer in men in the United States, and it is the second leading cause of cancer-related death in American men. The androgen receptor (AR), a receptor of nuclear family and a transcription factor, is the most important target in this disease. While most efforts in the clinic are currently directed at lowering levels of androgens that activate AR, resistance to androgen deprivation eventually develops. Most prostate cancer deaths are attributable to this castration-resistant form of prostate cancer (CRPC). Recent work has shed light on the importance of epigenetic events including facilitation of AR signaling by histone-modifying enzymes, posttranslational modifications of AR such as sumoylation. Herein, we provide an overview of the structure of human AR and its key structural domains that can be used as targets to develop novel antiandrogens. We also summarize recent findings about the antiandrogens and the epigenetic factors that modulate the action of AR.
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41
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Advances in small molecule inhibitors of androgen receptor for the treatment of advanced prostate cancer. World J Urol 2011; 30:311-8. [PMID: 21833557 DOI: 10.1007/s00345-011-0745-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 07/29/2011] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVES Current treatments for localized prostate cancer include brachytherapy, external beam radiation, surgery, and active surveillance. Unfortunately, 20-40% of prostate cancer patients will experience recurrence and require hormonal therapies. These therapies involve androgen ablation by chemical or surgical castration and application of antiandrogens. Hormonal therapy is initially effective, but will inevitably fail and the disease will progress to lethal castration-resistant prostate cancer (CRPC) from which patients succumb within 2 years. CRPC is considered to be dependent on transcriptionally active androgen receptors (AR). This article reviews recent advances in the discovery and development of small molecule inhibitors of AR. METHODS A PubMed database search was performed for articles focused on small molecule inhibitors of AR for potential development for the treatment of prostate cancer. Compounds with broad effects on other pathways were not included. RESULTS Currently, there are several novel antiandrogens being tested in the clinic that have improved affinity for the AR and work by different mechanisms to the current battery of approved antiandrogens that are discussed. Small molecule inhibitors that interact with regions other than the AR ligand-binding pocket have been also been discovered. These small molecules include allosteric inhibitors of the LBD, compounds that alter AR conformation, and antagonists to the AR NTD and are highlighted. CONCLUSIONS CRPC is dependent upon transcriptionally active AR. Survival improvement may be achieved by complete blockade of all AR activity using novel small molecule inhibitors with unique mechanisms of action.
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McEwan IJ. Intrinsic disorder in the androgen receptor: identification, characterisation and drugability. MOLECULAR BIOSYSTEMS 2011; 8:82-90. [PMID: 21822504 DOI: 10.1039/c1mb05249g] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The androgen receptor (AR) regulates networks of genes in response to the steroid hormones testosterone and dihydrotestosterone. The receptor protein is made up of both stably folded globular domains, involved in hormone and DNA binding, and regions of intrinsic disorder, including the N-terminal domain (NTD). The AR-NTD has a modular activation function (termed AF1) and is important for gene regulation, participating in multiple protein-protein interactions. Biophysical studies have revealed that AR-NTD/AF1 has limited stable secondary structure and conforms to a 'collapsed disordered' conformation. The AR-NTD/AF1 has the propensity to adopt an α-helical conformation in response to a natural osmolyte or a co-regulatory binding partner. The AR is a key drug target in the management of advanced prostate cancer and recently a small molecule inhibitor was identified that interacts with the NTD/AF1 and impairs protein-protein interactions and recruitment of the receptor to target genes. In this review the role of intrinsic disorder in AR function is discussed along with the potential to develop new drugs that will target the structurally plastic NTD.
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Affiliation(s)
- Iain J McEwan
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK.
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43
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Androgen receptor and its splice variants in prostate cancer. Cell Mol Life Sci 2011; 68:3971-81. [PMID: 21748469 DOI: 10.1007/s00018-011-0766-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/23/2011] [Accepted: 06/27/2011] [Indexed: 12/16/2022]
Abstract
Androgen receptor (AR) is a transcription factor that becomes active upon binding to androgens via its ligand-binding domain (LBD) or in response to signaling cascades initiated by growth factors and cytokines. The activity of AR requires regions within the N-terminal domain (NTD) in a manner that is distinct from the activation of related steroid hormone receptors. Unequivocal evidence has been amassed to consider that the AR axis is the most critical pathway for the progression of prostate cancer. Qualitatively distinct insights into AR pathobiology have been garnered including that AR-regulated gene expression is stage-specifically modulated during disease progression and that the ligand requirement for AR activity could be rendered dispensable because of the expression of constitutively active AR splice variants that are devoid of LBD. The recent appreciation of the clinical challenge that stems from non-gonadal androgens that are not inhibited by traditional hormonal therapies has been tangibly translated into the development of more potent drugs that can potentially lead towards achieving an androgen-free environment. The pre-clinical evidence that proves that AR NTD is a druggable target also forecasts a further paradigm shift in the management of advanced prostate cancer. These advancements together with the identification of more robust AR antagonists and their promising clinical outcome have renewed the hope that targeting the AR pathway remains a sound strategy in the clinical management of prostate cancer. Here, we address these developments with a greater emphasis on the rapidly growing literature on AR splice variants.
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44
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Peacock RWS, Wang CL. A genetic reporter system to gauge cell proliferation rate. Biotechnol Bioeng 2011; 108:2003-10. [PMID: 21495014 DOI: 10.1002/bit.23163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 03/30/2011] [Indexed: 12/18/2022]
Abstract
In higher eukaryotes, E2F transcription factors often drive expression of genes necessary for the cell cycle, notably the G1/S phase transition. With conventional transcriptional reporter systems, expression of a reporter gene from an E2F-responsive promoter would allow one to identify the fraction of cells making this transition. Here, we have engineered an E2F-responsive genetic reporter system that outputs the proliferation rate. The system takes advantage of the long half-lives of fluorescent protein reporters and output signal normalization. By doing so, it converts dynamic pulses of E2F activity into an analog output proportional to the proliferation rate. Such a system should be useful for applications involving high-throughput drug or genetic screens, investigation of cellular environment, and biological engineering.
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Affiliation(s)
- Ryan W S Peacock
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
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45
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Lamont KR, Tindall DJ. Minireview: Alternative activation pathways for the androgen receptor in prostate cancer. Mol Endocrinol 2011; 25:897-907. [PMID: 21436259 DOI: 10.1210/me.2010-0469] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Advanced prostate tumors, which are androgen dependent, are often initially treated in the clinic with hormone ablation therapy, either through surgical castration or administration of small-molecule antiandrogens. Most tumors respond favorably to these treatments, exhibiting regression of the tumor, amelioration of symptoms, and a decrease of prostate-specific antigen in patient sera. However, with time, the majority of tumors recur in a more aggressive, castration-resistant (CR) phenotype. Currently, no effective treatment exists for this stage of the cancer, and patients ultimately succumb to metastatic disease. The androgen receptor (AR), which is a member of the nuclear hormone receptor superfamily of proteins, is the transcription factor that is responsible for mediating the effects of androgens upon target tissues, and it has been demonstrated to play a central role in the development and progression of prostate cancer. Despite CR tumor cells being able to continue to grow after hormonal therapy in which testosterone and dihydrotestosterone are markedly reduced, they still require the expression and activity of the AR. The AR can become transactivated in this low-androgen environment through a number of different mechanisms, including amplification and mutation of the receptor, cross talk with other signaling pathways, and altered regulation by coregulatory proteins. This review will summarize the most current data regarding non-ligand-mediated activation of the AR in prostate cancer cells. Developing work in this field aims to more clearly elucidate the signals that drive AR activity independently of androgens in CR disease so that better therapeutic targets can be developed for patients with this stage of highly aggressive prostate carcinoma.
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Affiliation(s)
- Kristin R Lamont
- Department of Urology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, Minnesota 55901, USA
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46
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Sadar MD. Small molecule inhibitors targeting the "achilles' heel" of androgen receptor activity. Cancer Res 2011; 71:1208-13. [PMID: 21285252 DOI: 10.1158/0008-5472.can_10-3398] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Androgen ablation therapy remains the gold standard for the treatment of advanced prostate cancer, but unfortunately, it is not curative, and eventually the disease will return as lethal castration-resistant prostate cancer (CRPC). Mounting evidence supports the concept that development of CRPC is causally related to continued transactivation of androgen receptor (AR). All current therapies that target the AR are dependent on the presence of its C-terminal ligand-binding domain (LBD). However, it is the N-terminal domain (NTD) of the AR that is the "Achilles' heel" of AR activity, with AF-1 being essential for AR activity regardless of androgen. Recent efforts to develop drugs to the AR NTD have yielded EPI-001, a small molecule, sintokamide peptides, and decoys to the AR NTD with EPI-001, the best characterized and most promising for clinical development based upon specificity, low toxicity, and cytoreductive antitumor activity.
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Affiliation(s)
- Marianne D Sadar
- Department of Genome Sciences Centre, BC Cancer Agency, Vancouver, British Columbia, Canada.
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47
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Gao W. Androgen receptor as a therapeutic target. Adv Drug Deliv Rev 2010; 62:1277-84. [PMID: 20708648 DOI: 10.1016/j.addr.2010.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 08/04/2010] [Accepted: 08/05/2010] [Indexed: 11/19/2022]
Abstract
Androgens function as sex hormone primarily via activation of a single androgen receptor (AR, or NR3C4). AR is an important therapeutic target for the treatment of diseases such as hypogonadism and prostate cancer. AR ligands of different chemical structures and/or pharmacological properties are widely used for these therapeutic applications, and all of the AR ligands currently available for therapy modulate AR function via direct binding to the ligand-binding pocket (LBP) of the receptor. In the past ten years, our understanding of AR structure and molecular mechanism of action has progressed extensively, which has encouraged the rapid development of newer generation of AR ligands, particularly tissue-selective AR ligands. With improved tissue selectivity, future generations of AR ligands are expected to greatly expand the therapeutic applications of this class of drugs. This review will provide an overview of the common therapeutic applications of currently available AR ligands, and discussion of the major challenges as well as novel therapeutic strategies proposed for future drug development.
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Affiliation(s)
- Wenqing Gao
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo SUNY, 543 Cooke Hall, Buffalo, NY 14260, USA.
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48
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Andersen RJ, Mawji NR, Wang J, Wang G, Haile S, Myung JK, Watt K, Tam T, Yang YC, Bañuelos CA, Williams DE, McEwan IJ, Wang Y, Sadar MD. Regression of castrate-recurrent prostate cancer by a small-molecule inhibitor of the amino-terminus domain of the androgen receptor. Cancer Cell 2010; 17:535-46. [PMID: 20541699 DOI: 10.1016/j.ccr.2010.04.027] [Citation(s) in RCA: 386] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 03/27/2010] [Accepted: 05/10/2010] [Indexed: 11/25/2022]
Abstract
Castration-recurrent prostate cancer (CRPC) is suspected to depend on androgen receptor (AR). The AF-1 region in the amino-terminal domain (NTD) of AR contains most, if not all, of the transcriptional activity. Here we identify EPI-001, a small molecule that blocked transactivation of the NTD and was specific for inhibition of AR without attenuating transcriptional activities of related steroid receptors. EPI-001 interacted with the AF-1 region, inhibited protein-protein interactions with AR, and reduced AR interaction with androgen-response elements on target genes. Importantly, EPI-001 blocked androgen-induced proliferation and caused cytoreduction of CRPC in xenografts dependent on AR for growth and survival without causing toxicity.
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MESH Headings
- Androgen Receptor Antagonists
- Androgens/pharmacology
- Animals
- Antineoplastic Agents, Hormonal/adverse effects
- Antineoplastic Agents, Hormonal/pharmacology
- Antineoplastic Agents, Hormonal/therapeutic use
- Apoptosis/drug effects
- Benzhydryl Compounds/adverse effects
- Benzhydryl Compounds/pharmacology
- Benzhydryl Compounds/therapeutic use
- CREB-Binding Protein/metabolism
- Castration
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Chlorohydrins/adverse effects
- Chlorohydrins/pharmacology
- Chlorohydrins/therapeutic use
- DNA/genetics
- DNA/metabolism
- Gene Expression/drug effects
- Humans
- Ligands
- Male
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Molecular Structure
- Neoplasm Recurrence, Local/drug therapy
- Neoplasm Recurrence, Local/pathology
- Prostate/anatomy & histology
- Prostate/drug effects
- Prostate/pathology
- Prostate-Specific Antigen/blood
- Prostate-Specific Antigen/genetics
- Prostate-Specific Antigen/metabolism
- Prostatic Neoplasms/drug therapy
- Prostatic Neoplasms/pathology
- Prostatic Neoplasms/surgery
- Protein Binding/drug effects
- Protein Binding/genetics
- Protein Conformation/drug effects
- Protein Interaction Domains and Motifs/drug effects
- Protein Multimerization/drug effects
- Receptors, Androgen/metabolism
- Receptors, Steroid/drug effects
- Response Elements/genetics
- Serine Endopeptidases/genetics
- Transcriptional Activation/drug effects
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Raymond J Andersen
- Chemistry and Earth & Ocean Sciences, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1
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Knudsen KE, Scher HI. Starving the addiction: new opportunities for durable suppression of AR signaling in prostate cancer. Clin Cancer Res 2009; 15:4792-8. [PMID: 19638458 DOI: 10.1158/1078-0432.ccr-08-2660] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clinical data and models of human disease indicate that androgen receptor (AR) activity is essential for prostate cancer development, growth, and progression. The dependence of prostatic adenocarcinoma on AR signaling at all stages of disease has thereby been exploited in the treatment of disseminated tumors, for which ablation of AR function is the goal of first-line therapy. Although these strategies are initially effective, recurrent tumors arise with restored AR activity, and no durable treatment has yet been identified to combat this stage of disease. New insights into AR regulation and the mechanisms underlying resurgent AR activity have provided fertile ground for the development of novel strategies to more effectively inhibit receptor activity and prolong the transition to therapeutic failure.
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Affiliation(s)
- Karen E Knudsen
- Departments of Cancer Biology, Urology, and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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50
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Bergerat JP, Céraline J. Pleiotropic functional properties of androgen receptor mutants in prostate cancer. Hum Mutat 2009; 30:145-57. [PMID: 18800375 DOI: 10.1002/humu.20848] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The androgen receptor (AR) signaling pathway plays an important role during the development of the normal prostate gland, but also during the progression of prostate cancer on androgen ablation therapy. Mutations in the AR gene emerge to keep active the AR signaling pathway and to support prostate cancer cells growth and survival despite the low levels of circulating androgens. Indeed, mutations affecting the ligand binding domain (LBD) of the AR have been shown to generate so-called "promiscuous" receptors that present widened ligand specificity and allow the stimulation of these receptors by a larger spectrum of endogenous hormones. Another class of mutations, arising in the amino-terminal domain (NTD) of the receptor, modulate AR interactions with coregulators involved in cell proliferation regulation. Besides characteristics of these well-known types of mutations, the properties of other classes of AR mutants recently described in prostate cancer are currently under investigation. Most interestingly, in addition to their potential role in the mechanisms which allow prostate cancer cells to escape androgen ablation therapy, data suggest that certain AR mutations are present early in the natural history of the disease and may play a role in many aspects of prostate cancer progression. Surprisingly, singular truncated AR devoid of their carboxy-terminal end (CTE) region seem to exert specific paracrine effects and to induce a clonal cooperation with neighboring prostate cancer cells, which may facilitate both the invasion and metastasis processes. In this article, we review the functional properties of different classes of AR mutants and their potential impact on the natural history of prostate cancer. Hum Mutat 0, 1-14, 2008. (c) 2008 Wiley-Liss, Inc.
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Affiliation(s)
- Jean-Pierre Bergerat
- EA 3430-Signalisation et Cancer de la Prostate, Faculté de Médecine, Université Strasbourg, Strasbourg, France
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