1
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Blatti C, de la Fuente J, Gao H, Marín-Goñi I, Chen Z, Zhao SD, Tan W, Weinshilboum R, Kalari KR, Wang L, Hernaez M. Bayesian Machine Learning Enables Identification of Transcriptional Network Disruptions Associated with Drug-Resistant Prostate Cancer. Cancer Res 2023; 83:1361-1380. [PMID: 36779846 PMCID: PMC10102853 DOI: 10.1158/0008-5472.can-22-1910] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/29/2022] [Accepted: 02/08/2023] [Indexed: 02/14/2023]
Abstract
Survival rates of patients with metastatic castration-resistant prostate cancer (mCRPC) are low due to lack of response or acquired resistance to available therapies, such as abiraterone (Abi). A better understanding of the underlying molecular mechanisms is needed to identify effective targets to overcome resistance. Given the complexity of the transcriptional dynamics in cells, differential gene expression analysis of bulk transcriptomics data cannot provide sufficient detailed insights into resistance mechanisms. Incorporating network structures could overcome this limitation to provide a global and functional perspective of Abi resistance in mCRPC. Here, we developed TraRe, a computational method using sparse Bayesian models to examine phenotypically driven transcriptional mechanistic differences at three distinct levels: transcriptional networks, specific regulons, and individual transcription factors (TF). TraRe was applied to transcriptomic data from 46 patients with mCRPC with Abi-response clinical data and uncovered abrogated immune response transcriptional modules that showed strong differential regulation in Abi-responsive compared with Abi-resistant patients. These modules were replicated in an independent mCRPC study. Furthermore, key rewiring predictions and their associated TFs were experimentally validated in two prostate cancer cell lines with different Abi-resistance features. Among them, ELK3, MXD1, and MYB played a differential role in cell survival in Abi-sensitive and Abi-resistant cells. Moreover, ELK3 regulated cell migration capacity, which could have a direct impact on mCRPC. Collectively, these findings shed light on the underlying transcriptional mechanisms driving Abi response, demonstrating that TraRe is a promising tool for generating novel hypotheses based on identified transcriptional network disruptions. SIGNIFICANCE The computational method TraRe built on Bayesian machine learning models for investigating transcriptional network structures shows that disruption of ELK3, MXD1, and MYB signaling cascades impacts abiraterone resistance in prostate cancer.
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Affiliation(s)
- Charles Blatti
- NCSA, University of Illinois at Urbana-Champaign, Champaign, Illinois
| | | | - Huanyao Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Irene Marín-Goñi
- Computational Biology Program, CIMA University of Navarra, Navarra, Spain
| | - Zikun Chen
- Department of Computer Science, University of Illinois at Urbana-Champaign, Champaign, Illinois
| | - Sihai D. Zhao
- Department of Statistics, University of Illinois at Urbana-Champaign, Champaign, Illinois
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois
| | - Winston Tan
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Richard Weinshilboum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Krishna R. Kalari
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Mikel Hernaez
- Computational Biology Program, CIMA University of Navarra, Navarra, Spain
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois
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2
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Soave C, Ducker C, Islam N, Kim S, Yurgelevic S, Nicely NI, Pardy L, Huang Y, Shaw PE, Auner G, Dickson A, Ratnam M. The Small Molecule Antagonist KCI807 Disrupts Association of the Amino-Terminal Domain of the Androgen Receptor with ELK1 by Modulating the Adjacent DNA Binding Domain. Mol Pharmacol 2023; 103:211-220. [PMID: 36720643 PMCID: PMC11033959 DOI: 10.1124/molpharm.122.000589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 12/11/2022] [Accepted: 12/27/2022] [Indexed: 02/02/2023] Open
Abstract
The androgen receptor (AR) is a crucial coactivator of ELK1 for prostate cancer (PCa) growth, associating with ELK1 through two peptide segments (358-457 and 514-557) within the amino-terminal domain (NTD) of AR. The small-molecule antagonist 5-hydroxy-2-(3-hydroxyphenyl)chromen-4-one (KCI807) binds to AR, blocking ELK1 binding and inhibiting PCa growth. We investigated the mode of interaction of KCI807 with AR using systematic mutagenesis coupled with ELK1 coactivation assays, testing polypeptide binding and Raman spectroscopy. In full-length AR, deletion of neither ELK1 binding segment affected sensitivity of residual ELK1 coactivation to KCI807. Although the NTD is sufficient for association of AR with ELK1, interaction of the isolated NTD with ELK1 was insensitive to KCI807. In contrast, coactivation of ELK1 by the AR-V7 splice variant, comprising the NTD and the DNA binding domain (DBD), was sensitive to KCI807. Deletions and point mutations within DBD segment 558-595, adjacent to the NTD, interfered with coactivation of ELK1, and residual ELK1 coactivation by the mutants was insensitive to KCI807. In a glutathione S-transferase pull-down assay, KCI807 inhibited ELK1 binding to an AR polypeptide that included the two ELK1 binding segments and the DBD but did not affect ELK1 binding to a similar AR segment that lacked the sequence downstream of residue 566. Raman spectroscopy detected KCI807-induced conformational change in the DBD. The data point to a putative KCI807 binding pocket within the crystal structure of the DBD and indicate that either mutations or binding of KCI807 at this site will induce conformational changes that disrupt ELK1 binding to the NTD. SIGNIFICANCE STATEMENT: The small-molecule antagonist KCI807 disrupts association of the androgen receptor (AR) with ELK1, serving as a prototype for the development of small molecules for a novel type of therapeutic intervention in drug-resistant prostate cancer. This study provides basic information needed for rational KCI807-based drug design by identifying a putative binding pocket in the DNA binding domain of AR through which KCI807 modulates the amino-terminal domain to inhibit ELK1 binding.
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Affiliation(s)
- Claire Soave
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Charles Ducker
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Naeyma Islam
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Seongho Kim
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Sally Yurgelevic
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Nathan I Nicely
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Luke Pardy
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Yanfang Huang
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Peter E Shaw
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Gregory Auner
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Alex Dickson
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
| | - Manohar Ratnam
- Department of Oncology (C.S., S.K., Y.H., L.P., M.R.) and Smart Sensors and Integrated Microsystems (SSIM) Program (S.Y., G.A.), Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan; Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, East Lansing, Michigan (N.I. and A.D.); School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom (C.D. and P.E.S.); and Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina (N.N.)
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3
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Ducker C, Ratnam M, Shaw PE, Layfield R. Comparative analysis of protein expression systems and PTM landscape in the study of transcription factor ELK-1. Protein Expr Purif 2023; 203:106216. [PMID: 36528218 DOI: 10.1016/j.pep.2022.106216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/06/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Post-translational modifications (PTMs) are important for protein folding and activity, and the ability to recreate physiologically relevant PTM profiles on recombinantly-expressed proteins is vital for meaningful functional analysis. The ETS transcription factor ELK-1 serves as a paradigm for cellular responses to mitogens and can synergise with androgen receptor to promote prostate cancer progression, although in vitro protein function analyses to date have largely overlooked its complex PTM landscapes. We expressed and purified human ELK-1 using mammalian (HEK293T), insect (Sf9) and bacterial (E. coli) systems in parallel and compared PTMs imparted upon purified proteins, along with their performance in DNA and protein interaction assays. Phosphorylation of ELK-1 within its transactivation domain, known to promote DNA binding, was most apparent in protein isolated from human cells and accordingly conferred the strongest DNA binding in vitro, while protein expressed in insect cells bound most efficiently to the androgen receptor. We observed lysine acetylation, a hitherto unreported PTM of ELK-1, which appeared highest in insect cell-derived ELK-1 but was also present in HEK293T-derived ELK-1. Acetylation of ELK-1 was enhanced in HEK293T cells following starvation and mitogen stimulation, and modified lysines showed overlap with previously identified regulatory SUMOylation and ubiquitination sites. Our data demonstrate that the choice of recombinant expression system can be tailored to suit biochemical application rather than to maximise soluble protein production and suggest the potential for crosstalk and antagonism between different PTMs of ELK-1.
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Affiliation(s)
- Charles Ducker
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.
| | - Manohar Ratnam
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
| | - Peter E Shaw
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Robert Layfield
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
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4
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Identification of ELK1 interacting peptide segments in the androgen receptor. Biochem J 2022; 479:1519-1531. [PMID: 35781489 DOI: 10.1042/bcj20220297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/17/2022]
Abstract
Prostate cancer (PCa) growth requires tethering of the androgen receptor (AR) to chromatin by the ETS domain transcription factor ELK1 to coactivate critical cell proliferation genes. Disruption of the ELK1-AR complex is a validated potential means of therapeutic intervention in PCa. AR associates with ELK1 by co-opting its two ERK docking sites, through the amino-terminal domain (A/B domain) of AR. Using a mammalian two-hybrid assay, we have now functionally mapped amino acids within the peptide segments 358-457 and 514-557 in the A/B domain as required for association with ELK1. The mapping data was validated by GST (glutathione S-transferase)-pulldown and BRET (bioluminescence resonance energy transfer) assays. Comparison of the relative contributions of the interacting motifs/segments in ELK1 and AR to coactivation of ELK1 by AR suggested a parallel mode of binding of AR and ELK1 polypeptides. Growth of PCa cells was partially inhibited by deletion of the upstream segment in AR and nearly fully inhibited by deletion of the downstream segment. Our studies have identified two peptide segments in AR that mediate functional association of AR with its two docking sites in ELK1. Identification of the ELK1 recognition sites in AR should enable further structural studies of the ELK1-AR interaction and rational design of small molecule drugs to disrupt this interaction.
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5
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Azam H, Pierro L, Reina M, Gallagher WM, Prencipe M. Emerging role for the Serum Response Factor (SRF) as a potential therapeutic target in cancer. Expert Opin Ther Targets 2022; 26:155-169. [PMID: 35114091 DOI: 10.1080/14728222.2022.2032652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The Serum Response Factor (SRF) is a transcription factor involved in three hallmarks of cancer: the promotion of cell proliferation, cell death resistance and invasion and metastasis induction. Many studies have demonstrated a leading role in the development and progression of multiple cancer types, thus highlighting the potential of SRF as a prognostic biomarker and therapeutic target, especially for cancers with poor prognosis. AREAS COVERED This review examines the role of SRF in several cancers in promoting cellular processes associated with cancer development and progression. SRF co-factors and signalling pathways are discussed as possible targets to inhibit SRF in a tissue and cancer-specific way. Small-molecule inhibitors of SRF, such as the CCGs series of compounds and lestaurtinib, which could be used as cancer therapeutics, are also discussed. EXPERT OPINION Targeting of SRF and its co-factors represents a promising therapeutic approach. Further understanding of the molecular mechanisms behind the action of SRF could provide a pipeline of novel molecular targets and therapeutic combinations for cancer. Basket clinical trials and the use of SRF immunohistochemistry as companion diagnostics will help testing of these new targets in patients.
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Affiliation(s)
- Haleema Azam
- Cancer Biology and Therapeutics Laboratory, UCD Conway Institute, University College Dublin, Belfield, D4, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, D4, Dublin, Ireland
| | - Lisa Pierro
- Cancer Biology and Therapeutics Laboratory, UCD Conway Institute, University College Dublin, Belfield, D4, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, D4, Dublin, Ireland
| | - Martina Reina
- Cancer Biology and Therapeutics Laboratory, UCD Conway Institute, University College Dublin, Belfield, D4, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, D4, Dublin, Ireland
| | - William M Gallagher
- Cancer Biology and Therapeutics Laboratory, UCD Conway Institute, University College Dublin, Belfield, D4, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, D4, Dublin, Ireland
| | - Maria Prencipe
- Cancer Biology and Therapeutics Laboratory, UCD Conway Institute, University College Dublin, Belfield, D4, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, D4, Dublin, Ireland
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Ducker C, Shaw PE. Ubiquitin-Mediated Control of ETS Transcription Factors: Roles in Cancer and Development. Int J Mol Sci 2021; 22:5119. [PMID: 34066106 PMCID: PMC8151852 DOI: 10.3390/ijms22105119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022] Open
Abstract
Genome expansion, whole genome and gene duplication events during metazoan evolution produced an extensive family of ETS genes whose members express transcription factors with a conserved winged helix-turn-helix DNA-binding domain. Unravelling their biological roles has proved challenging with functional redundancy manifest in overlapping expression patterns, a common consensus DNA-binding motif and responsiveness to mitogen-activated protein kinase signalling. Key determinants of the cellular repertoire of ETS proteins are their stability and turnover, controlled largely by the actions of selective E3 ubiquitin ligases and deubiquitinases. Here we discuss the known relationships between ETS proteins and enzymes that determine their ubiquitin status, their integration with other developmental signal transduction pathways and how suppression of ETS protein ubiquitination contributes to the malignant cell phenotype in multiple cancers.
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Affiliation(s)
- Charles Ducker
- Queen’s Medical Centre, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Peter E. Shaw
- Queen’s Medical Centre, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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7
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MED19 alters AR occupancy and gene expression in prostate cancer cells, driving MAOA expression and growth under low androgen. PLoS Genet 2021; 17:e1008540. [PMID: 33513133 PMCID: PMC7875385 DOI: 10.1371/journal.pgen.1008540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/10/2021] [Accepted: 01/04/2021] [Indexed: 11/19/2022] Open
Abstract
Androgen deprivation therapy (ADT) is a mainstay of prostate cancer treatment, given the dependence of prostate cells on androgen and the androgen receptor (AR). However, tumors become ADT-resistant, and there is a need to understand the mechanism. One possible mechanism is the upregulation of AR co-regulators, although only a handful have been definitively linked to disease. We previously identified the Mediator subunit MED19 as an AR co-regulator, and reported that MED19 depletion inhibits AR transcriptional activity and growth of androgen-insensitive LNCaP-abl cells. Therefore, we proposed that MED19 upregulation would promote AR activity and drive androgen-independent growth. Here, we show that stable overexpression of MED19 in androgen-dependent LNCaP cells promotes growth under conditions of androgen deprivation. To delineate the mechanism, we determined the MED19 and AR transcriptomes and cistromes in control and MED19-overexpressing LNCaP cells. We also examined genome-wide H3K27 acetylation. MED19 overexpression selectively alters AR occupancy, H3K27 acetylation, and gene expression. Under conditions of androgen deprivation, genes regulated by MED19 correspond to genes regulated by ELK1, a transcription factor that binds the AR N-terminus to induce select AR target gene expression and proliferation, and genomic sites occupied by MED19 and AR are enriched for motifs associated with ELK1. Strikingly, MED19 upregulates expression of monoamine oxidase A (MAOA), a factor that promotes prostate cancer growth. MAOA depletion reduces androgen-independent growth. MED19 and AR occupy the MAOA promoter, with MED19 overexpression enhancing AR occupancy and H3K27 acetylation. Furthermore, MED19 overexpression increases ELK1 occupancy at the MAOA promoter, and ELK1 depletion reduces MAOA expression and androgen-independent growth. This suggests that MED19 cooperates with ELK1 to regulate AR occupancy and H3K27 acetylation at MAOA, upregulating its expression and driving androgen independence in prostate cancer cells. This study provides important insight into the mechanisms of prostate cancer cell growth under low androgen, and underscores the importance of the MED19-MAOA axis in this process.
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8
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Lu C, Brown LC, Antonarakis ES, Armstrong AJ, Luo J. Androgen receptor variant-driven prostate cancer II: advances in laboratory investigations. Prostate Cancer Prostatic Dis 2020; 23:381-397. [PMID: 32139878 PMCID: PMC7725416 DOI: 10.1038/s41391-020-0217-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 02/17/2020] [Accepted: 02/19/2020] [Indexed: 02/07/2023]
Abstract
Background: The androgen receptor (AR) is a key prostate cancer drug target.
Suppression of AR signaling mediated by the full-length AR (AR-FL) is the
therapeutic goal of all existing AR-directed therapies. AR-targeting agents
impart therapeutic benefit, but lead to AR aberrations that underlie disease
progression and therapeutic resistance. Among the AR aberrations specific to
castration-resistant prostate cancer (CRPC), AR variants (AR-Vs) have
emerged as important indicators of disease progression and therapeutic
resistance. Methods: We conducted a systemic review of the literature focusing on recent
laboratory studies on AR-Vs following our last review article published in
2016. Topics ranged from measurement and detection, molecular origin,
regulation, genomic function, and preclinical therapeutic targeting of
AR-Vs. We provide expert opinions and perspectives on these topics. Results: Transcript sequences for 22 AR-Vs have been reported in the
literature. Different AR-Vs may arise through different mechanisms, and can
be regulated by splicing factors and dictated by genomic rearrangements, but
a low-androgen environment is a prerequisite for generation of AR-Vs. The
unique transcript structures allowed development of in-situ and in-solution
measurement and detection methods, including mRNA and protein detection, in
both tissue and blood specimens. AR variant-7 (AR-V7) remains the main
measurement target and the most extensively characterized AR-V. Although
AR-V7 co-exists with AR-FL, genomic functions mediated by AR-V7 do not
require the presence of AR-FL. The distinct cistromes and transcriptional
programs directed by AR-V7 and their co-regulators are consistent with
genomic features of progressive disease in a low-androgen environment.
Preclinical development of AR-V-directed agents currently focuses on
suppression of mRNA expression and protein degradation as well as targeting
of the amino-terminal domain. Conclusions: Current literature continues to support AR-Vs as biomarkers and
therapeutic targets in prostate cancer. Laboratory investigations reveal
both challenges and opportunities in targeting AR-Vs to overcome resistance
to current AR-directed therapies.
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Affiliation(s)
- Changxue Lu
- Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Landon C Brown
- Departments of Medicine, Surgery, and Pharmacology and Cancer Biology, Divisions of Medical Oncology and Urology, Duke Cancer Institute Center for Prostate and Urologic Cancers, Duke University, Durham, NC, USA
| | - Emmanuel S Antonarakis
- Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Departments of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Andrew J Armstrong
- Departments of Medicine, Surgery, and Pharmacology and Cancer Biology, Divisions of Medical Oncology and Urology, Duke Cancer Institute Center for Prostate and Urologic Cancers, Duke University, Durham, NC, USA
| | - Jun Luo
- Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Departments of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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9
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Pardy L, Rosati R, Soave C, Huang Y, Kim S, Ratnam M. The ternary complex factor protein ELK1 is an independent prognosticator of disease recurrence in prostate cancer. Prostate 2020; 80:198-208. [PMID: 31794091 PMCID: PMC7302117 DOI: 10.1002/pros.23932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/18/2019] [Indexed: 01/28/2023]
Abstract
BACKGROUND Both hormone-sensitive and castration- and enzalutamide-resistant prostate cancers (PCa) depend on the ternary complex factor (TCF) protein ELK1 to serve as a tethering protein for the androgen receptor (AR) to activate a critical set of growth genes. The two sites in ELK1 required for AR binding are conserved in other members of the TCF subfamily, ELK3 and ELK4. Here we examine the potential utility of the three proteins as prognosticators of disease recurrence in PCa. METHODS Transcriptional activity assays; Retrospective analysis of PCa recurrence using data on 501 patients in The Cancer Genome Atlas (TCGA) database; Unpaired Wilcoxon rank-sum test and multiple comparison correction using the Holm's method; Spearman's correlations; Kaplan-Meier methods; Univariable and multivariable Cox regression analyses; LASSO-based penalized Cox regression models; Time-dependent area under the receiver operating characteristic (ROC) curve. RESULTS ELK4 but not ELK3 was coactivated by AR similar to ELK1. Tumor expression of neither ELK3 nor ELK4 was associated with disease-free survival (DFS). ELK1 was associated with higher clinical T-stage, pathology T-stage, Gleason score, prognostic grade, and positive lymph node status. ELK1 was a negative prognosticator of DFS, independent of ELK3, ELK4, clinical T-stage, pathology T-stage, prognostic grade, lymph node status, age, and race. Inclusion of ELK1 increased the abilities of the Oncotype DX and Prolaris gene panels to predict disease recurrence, correctly predicting disease recurrence in a unique subset of patients. CONCLUSIONS ELK1 is a strong, independent prognosticator of disease recurrence in PCa, underscoring its unique role in PCa growth. Inclusion of ELK1 may enhance the utility of currently used prognosticators for clinical decision making in prostate cancer.
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Affiliation(s)
- Luke Pardy
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Rayna Rosati
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Claire Soave
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Yanfang Huang
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Seongho Kim
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Manohar Ratnam
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
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10
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Ducker C, Chow LKY, Saxton J, Handwerger J, McGregor A, Strahl T, Layfield R, Shaw PE. De-ubiquitination of ELK-1 by USP17 potentiates mitogenic gene expression and cell proliferation. Nucleic Acids Res 2019; 47:4495-4508. [PMID: 30854565 PMCID: PMC6511843 DOI: 10.1093/nar/gkz166] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 01/06/2023] Open
Abstract
ELK-1 is a transcription factor involved in ERK-induced cellular proliferation. Here, we show that its transcriptional activity is modulated by ubiquitination at lysine 35 (K35). The level of ubiquitinated ELK-1 rises in mitogen-deprived cells and falls upon mitogen stimulation or oncogene expression. Ectopic expression of USP17, a cell cycle-dependent deubiquitinase, decreases ELK-1 ubiquitination and up-regulates ELK-1 target-genes with a concomitant increase in cyclin D1 expression. In contrast, USP17 depletion attenuates ELK-1-dependent gene expression and slows cell proliferation. The reduced rate of proliferation upon USP17 depletion appears to be a direct effect of ELK-1 ubiquitination because it is rescued by an ELK-1(K35R) mutant refractory to ubiquitination. Overall, our results show that ubiquitination of ELK-1 at K35, and its reversal by USP17, are important mechanisms in the regulation of nuclear ERK signalling and cellular proliferation. Our findings will be relevant for tumours that exhibit elevated USP17 expression and suggest a new target for intervention.
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Affiliation(s)
- Charles Ducker
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Leo Kam Yuen Chow
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Janice Saxton
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Jürgen Handwerger
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Alexander McGregor
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Thomas Strahl
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Robert Layfield
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Peter E Shaw
- Transcription and Molecular Signalling Laboratory, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
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11
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Chowdhury D, Singh A, Gupta A, Tulsawani R, Meena RC, Chakrabarti A. p38 MAPK pathway-dependent SUMOylation of Elk-1 and phosphorylation of PIAS2 correlate with the downregulation of Elk-1 activity in heat-stressed HeLa cells. Cell Stress Chaperones 2019; 24:393-407. [PMID: 30783905 PMCID: PMC6439063 DOI: 10.1007/s12192-019-00974-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 01/10/2019] [Accepted: 01/15/2019] [Indexed: 01/01/2023] Open
Abstract
Stress-activated and mitogen-activated protein kinases (MAPKs) regulate gene expression by post-translational modifications of transcription factors. Elk-1, a transcription factor that regulates the expression of immediate early genes, is amenable to regulation by all the three mammalian MAPKs. In the present report, using inhibitors specific for different MAPK pathways, we show that during exposure of HeLa cells to heat stress, Elk-1 is SUMOylated with SUMO1 by p38 MAPK pathway-dependent mechanisms. Elk-1-phosphorylation levels were significantly reduced under similar conditions. We also show that transcriptional activity of Elk-1 as assessed by luciferase reporter expression and qPCR estimation of the expression of genes regulated by Elk-1 was downregulated upon exposure to heat stress; this downregulation was reversed when heat exposure was performed in the presence of either SB203580 (p38 MAPK inhibitor) or ginkgolic acid (inhibitor of SUMOylation). Elk-1 induced transcription is also regulated by PIAS2 which acts as a coactivator upon the activation of extracellular signal-regulated kinases (ERKs) and as a corepressor upon its phosphorylation by p38 MAPK. Since heat stress activates the p38 MAPK pathway, we determined if PIAS2 was phosphorylated in heat-stressed HeLa cells. Our studies indicate that in HeLa cells exposed to heat stress, PIAS2 is phosphorylated by p38 MAPK pathway-dependent mechanisms. Collectively, the results presented demonstrate that in heat-stressed HeLa cells, p38 MAPK pathway-dependent SUMOylation of Elk-1 and phosphorylation of PIAS2 correlate with the downregulation of transactivation by Elk-1.
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Affiliation(s)
- Daipayan Chowdhury
- Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Ajeet Singh
- Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Avinash Gupta
- Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Rajkumar Tulsawani
- Department of Chemistry, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Ramesh Chand Meena
- Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India.
| | - Amitabha Chakrabarti
- Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India.
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12
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Rosati R, Polin L, Ducker C, Li J, Bao X, Selvakumar D, Kim S, Xhabija B, Larsen M, McFall T, Huang Y, Kidder BL, Fribley A, Saxton J, Kakuta H, Shaw P, Ratnam M. Strategy for Tumor-Selective Disruption of Androgen Receptor Function in the Spectrum of Prostate Cancer. Clin Cancer Res 2018; 24:6509-6522. [PMID: 30185422 PMCID: PMC6295231 DOI: 10.1158/1078-0432.ccr-18-0982] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 08/03/2018] [Accepted: 08/31/2018] [Indexed: 11/16/2022]
Abstract
PURPOSE Testosterone suppression in prostate cancer is limited by serious side effects and resistance via restoration of androgen receptor (AR) functionality. ELK1 is required for AR-dependent growth in various hormone-dependent and castration-resistant prostate cancer models. The amino-terminal domain of AR docks at two sites on ELK1 to coactivate essential growth genes. This study explores the ability of small molecules to disrupt the ELK1-AR interaction in the spectrum of prostate cancer, inhibiting AR activity in a manner that would predict functional tumor selectivity. EXPERIMENTAL DESIGN Small-molecule drug discovery and extensive biological characterization of a lead compound. RESULTS We have discovered a lead molecule (KCI807) that selectively disrupts ELK1-dependent promoter activation by wild-type and variant ARs without interfering with ELK1 activation by ERK. KCI807 has an obligatory flavone scaffold and functional hydroxyl groups on C5 and C3'. KCI807 binds to AR, blocking ELK1 binding, and selectively blocks recruitment of AR to chromatin by ELK1. KCI807 primarily affects a subset of AR target growth genes selectively suppressing AR-dependent growth of prostate cancer cell lines with a better inhibitory profile than enzalutamide. KCI807 also inhibits in vivo growth of castration/enzalutamide-resistant cell line-derived and patient-derived tumor xenografts. In the rodent model, KCI807 has a plasma half-life of 6 hours, and maintenance of its antitumor effect is limited by self-induced metabolism at its 3'-hydroxyl. CONCLUSIONS The results offer a mechanism-based therapeutic paradigm for disrupting the AR growth-promoting axis in the spectrum of prostate tumors while reducing global suppression of testosterone actions. KCI807 offers a good lead molecule for drug development.
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Affiliation(s)
- Rayna Rosati
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Lisa Polin
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Charles Ducker
- School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom
| | - Jing Li
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Xun Bao
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Dakshnamurthy Selvakumar
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Seongho Kim
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Besa Xhabija
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
- Department of Chemistry and Biochemistry, University of Michigan-Flint, Flint, Michigan
| | - Martha Larsen
- University of Michigan, Life Sciences Institute and Center for Chemical Genomics, Ann Arbor, Michigan
| | - Thomas McFall
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Yanfang Huang
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Benjamin L Kidder
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Andrew Fribley
- Department of Pediatrics, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Janice Saxton
- School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom
| | - Hiroki Kakuta
- Division of Pharmaceutical Sciences, Graduate School of Medicine, Okayama University, Okayama, Japan
| | - Peter Shaw
- School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom
| | - Manohar Ratnam
- Department of Oncology, Wayne State University School of Medicine and Barbara Ann Karmanos Cancer Institute, Detroit, Michigan.
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13
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AIRE promotes androgen-independent prostate cancer by directly regulating IL-6 and modulating tumor microenvironment. Oncogenesis 2018; 7:43. [PMID: 29795364 PMCID: PMC5968032 DOI: 10.1038/s41389-018-0053-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/29/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023] Open
Abstract
Early stage prostate cancers are dependent on androgens for their growth and survival and androgen withdrawal causes them to regress. Progressive prostate cancers eventually acquire androgen independence rendering anti-androgen therapy ineffective. However, the factors leading to this have not been adequately addressed. This study shows that AIRE finds differential expression in androgen-dependent and -independent prostate cancer cells. AIRE expression is more in androgen-independent cells due to its regulation by transcription factor Elk-1. These enhanced levels of AIRE modulate the prostate tumor microenvironment by transcriptionally activating a malignancy gene IL-6 in androgen-independent cells. Additionally, AIRE prevents the cancer cells from anticancer drug-induced death and enhances their invasiveness. Moreover, AIRE by modulating the cytokine milieu skews the tumor-associated macrophage polarization towards M2 phenotype with increased CD206 and CD163 expression. Subcutaneous mouse model of prostate cancer revealed AIRE+/+ mice forming a palpable tumor and presents lymphadenopathy however, only a small benign tumor is observed in AIRE−/− mice and lymph nodes appear normal in size. In conclusion, our findings suggest AIRE as a probable factor in promoting prostate cancer progression.
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