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van Genderen MNG, Kneppers J, Zaalberg A, Bekers EM, Bergman AM, Zwart W, Eduati F. Agent-based modeling of the prostate tumor microenvironment uncovers spatial tumor growth constraints and immunomodulatory properties. NPJ Syst Biol Appl 2024; 10:20. [PMID: 38383542 PMCID: PMC10881528 DOI: 10.1038/s41540-024-00344-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 01/25/2024] [Indexed: 02/23/2024] Open
Abstract
Inhibiting androgen receptor (AR) signaling through androgen deprivation therapy (ADT) reduces prostate cancer (PCa) growth in virtually all patients, but response may be temporary, in which case resistance develops, ultimately leading to lethal castration-resistant prostate cancer (CRPC). The tumor microenvironment (TME) plays an important role in the development and progression of PCa. In addition to tumor cells, TME-resident macrophages and fibroblasts express AR and are therefore also affected by ADT. However, the interplay of different TME cell types in the development of CRPC remains largely unexplored. To understand the complex stochastic nature of cell-cell interactions, we created a PCa-specific agent-based model (PCABM) based on in vitro cell proliferation data. PCa cells, fibroblasts, "pro-inflammatory" M1-like and "pro-tumor" M2-like polarized macrophages are modeled as agents from a simple set of validated base assumptions. PCABM allows us to simulate the effect of ADT on the interplay between various prostate TME cell types. The resulting in vitro growth patterns mimic human PCa. Our PCABM can effectively model hormonal perturbations by ADT, in which PCABM suggests that CRPC arises in clusters of resistant cells, as is observed in multifocal PCa. In addition, fibroblasts compete for cellular space in the TME while simultaneously creating niches for tumor cells to proliferate in. Finally, PCABM predicts that ADT has immunomodulatory effects on macrophages that may enhance tumor survival. Taken together, these results suggest that AR plays a critical role in the cellular interplay and stochastic interactions in the TME that influence tumor cell behavior and CRPC development.
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Affiliation(s)
- Maisa N G van Genderen
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Jeroen Kneppers
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Anniek Zaalberg
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Elise M Bekers
- Division of Pathology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Andries M Bergman
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
- Division of Medical Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| | - Wilbert Zwart
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands.
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands.
| | - Federica Eduati
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands.
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Vadukoot AK, Mottemmal S, Vekaria PH. Curcumin as a Potential Therapeutic Agent in Certain Cancer Types. Cureus 2022; 14:e22825. [PMID: 35399416 PMCID: PMC8980239 DOI: 10.7759/cureus.22825] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2022] [Indexed: 12/17/2022] Open
Abstract
Cancer is a devastating disease condition and is the second most common etiology of death globally. After decades of research in the field of hematological malignancies and cellular therapeutics, we are still looking for therapeutic agents with the most efficacies and least toxicities. Curcumin is one of the cancer therapeutic agents that is derived from the Curcuma longa (turmeric) plant, and still in vitro and in vivo research is going on to find its beneficial effects on various cancers. Due to its potency to affect multiple targets of different cellular pathways, it is considered a promising agent to tackle various cancers alone or in combination with the existing chemotherapies. This review covers basic properties, mechanism of action, potential targets (molecules and cell-signaling pathways) of curcumin, as well as its effect on various solid and hematological malignancies.
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Kneppers J, Bergman AM, Zwart W. Prostate Cancer Epigenetic Plasticity and Enhancer Heterogeneity: Molecular Causes, Consequences and Clinical Implications. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:255-275. [DOI: 10.1007/978-3-031-11836-4_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/20/2024]
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Curcumin against Prostate Cancer: Current Evidence. Biomolecules 2020; 10:biom10111536. [PMID: 33182828 PMCID: PMC7696488 DOI: 10.3390/biom10111536] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/30/2020] [Accepted: 11/04/2020] [Indexed: 12/21/2022] Open
Abstract
Cancer is a condition characterized by remarkably enhanced rates of cell proliferation paired with evasion of cell death. These deregulated cellular processes take place following genetic mutations leading to the activation of oncogenes, the loss of tumor suppressor genes, and the disruption of key signaling pathways that control and promote homeostasis. Plant extracts and plant-derived compounds have historically been utilized as medicinal remedies in different cultures due to their anti-inflammatory, antioxidant, and antimicrobial properties. Many chemotherapeutic agents used in the treatment of cancer are derived from plants, and the scientific interest in discovering plant-derived chemicals with anticancer potential continues today. Curcumin, a turmeric-derived polyphenol, has been reported to possess antiproliferative and proapoptotic properties. In the present review, we summarize all the in vitro and in vivo studies examining the effects of curcumin in prostate cancer.
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Vickman RE, Franco OE, Moline DC, Vander Griend DJ, Thumbikat P, Hayward SW. The role of the androgen receptor in prostate development and benign prostatic hyperplasia: A review. Asian J Urol 2020; 7:191-202. [PMID: 32742923 PMCID: PMC7385520 DOI: 10.1016/j.ajur.2019.10.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/30/2019] [Accepted: 06/18/2019] [Indexed: 02/06/2023] Open
Abstract
Benign prostatic hyperplasia (BPH) is a benign enlargement of the prostate in which incidence increases linearly with age, beginning at about 50 years old. BPH is a significant source of morbidity in aging men by causing lower urinary tract symptoms and acute urinary retention. Unfortunately, the etiology of BPH incidence and progression is not clear. This review highlights the role of the androgen receptor (AR) in prostate development and the evidence for its involvement in BPH. The AR is essential for normal prostate development, and individuals with defective AR signaling, such as after castration, do not experience prostate enlargement with age. Furthermore, decreasing dihydrotestosterone availability through therapeutic targeting with 5α-reductase inhibitors diminishes AR activity and results in reduced prostate size and symptoms in some BPH patients. While there is some evidence that AR expression is elevated in certain cellular compartments, how exactly AR is involved in BPH progression has yet to be elucidated. It is possible that AR signaling within stromal cells alters intercellular signaling and a "reawakening" of the embryonic mesenchyme, loss of epithelial AR leads to changes in paracrine signaling interactions, and/or chronic inflammation aids in stromal or epithelial proliferation evident in BPH. Unfortunately, a subset of patients fails to respond to current medical approaches, forcing surgical treatment even though age or associated co-morbidities make surgery less attractive. Fundamentally, new therapeutic approaches to treat BPH are not currently forthcoming, so a more complete molecular understanding of BPH etiology is necessary to identify new treatment options.
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Affiliation(s)
- Renee E. Vickman
- Department of Surgery, NorthShore University HealthSystem, Evanston, IL, USA
| | - Omar E. Franco
- Department of Surgery, NorthShore University HealthSystem, Evanston, IL, USA
| | - Daniel C. Moline
- Department of Pathology, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Praveen Thumbikat
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Simon W. Hayward
- Department of Surgery, NorthShore University HealthSystem, Evanston, IL, USA
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Pungsrinont T, Sutter MF, Ertingshausen MCCM, Lakshmana G, Kokal M, Khan AS, Baniahmad A. Senolytic compounds control a distinct fate of androgen receptor agonist- and antagonist-induced cellular senescent LNCaP prostate cancer cells. Cell Biosci 2020; 10:59. [PMID: 32351687 PMCID: PMC7183592 DOI: 10.1186/s13578-020-00422-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Background The benefit of inducing cellular senescence as a tumor suppressive strategy remains questionable due to the senescence-associated secretory phenotype. Hence, studies and development of senolytic compounds that induce cell death in senescent cells have recently emerged. Senescent cells are hypothesized to exhibit different upregulated pro-survival/anti-apoptotic networks depending on the senescent inducers. This might limit the effect of a particular senolytic compound that targets rather only a specific pathway. Interestingly, cellular senescence in prostate cancer (PCa) cells can be induced by either androgen receptor (AR) agonists at supraphysiological androgen level (SAL) used in bipolar androgen therapy or by AR antagonists. This challenges to define ligand-specific senolytic compounds. Results Here, we first induced cellular senescence by treating androgen-sensitive PCa LNCaP cells with either SAL or the AR antagonist Enzalutamide (ENZ). Subsequently, cells were incubated with the HSP90 inhibitor Ganetespib (GT), the Bcl-2 family inhibitor ABT263, or the Akt inhibitor MK2206 to analyze senolysis. GT and ABT263 are known senolytic compounds. We observed that GT exhibits senolytic activity specifically in SAL-pretreated PCa cells. Mechanistically, GT treatment results in reduction of AR, Akt, and phospho-S6 (p-S6) protein levels. Surprisingly, ABT263 lacks senolytic effect in both AR agonist- and antagonist-pretreated cells. ABT263 treatment does not affect AR, Akt, or S6 protein levels. Treatment with MK2206 does not reduce AR protein level and, as expected, potently inhibits Akt phosphorylation. However, ENZ-induced cellular senescent cells undergo apoptosis by MK2206, whereas SAL-treated cells are resistant. In line with this, we reveal that the pro-survival p-S6 level is higher in SAL-induced cellular senescent PCa cells compared to ENZ-treated cells. These data indicate a difference in the agonist- or antagonist-induced cellular senescence and suggest a novel role of MK2206 as a senolytic agent preferentially for AR antagonist-treated cells. Conclusion Taken together, our data suggest that both AR agonist and antagonist induce cellular senescence but differentially upregulate a pro-survival signaling which preferentially sensitize androgen-sensitive PCa LNCaP cells to a specific senolytic compound.
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Affiliation(s)
- Thanakorn Pungsrinont
- 1Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740 Jena, Germany
| | - Malika Franziska Sutter
- 1Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740 Jena, Germany.,2Department of Hematology and Medical Oncology, Jena University Hospital, Jena, Germany
| | | | - Gopinath Lakshmana
- 1Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740 Jena, Germany
| | - Miriam Kokal
- 1Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740 Jena, Germany
| | - Amir Saeed Khan
- 1Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740 Jena, Germany.,3Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University Hospital Cologne, Cologne, Germany
| | - Aria Baniahmad
- 1Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740 Jena, Germany
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Jin ML, Kim YW, Jeong KW. BAF53A regulates androgen receptor-mediated gene expression and proliferation in LNCaP cells. Biochem Biophys Res Commun 2018; 505:618-623. [PMID: 30278885 DOI: 10.1016/j.bbrc.2018.09.149] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 09/22/2018] [Indexed: 11/30/2022]
Abstract
The actin-like protein of the SWI/SNF complex, BAF53A, regulates gene expression by the gene-specific chromatin remodeling of target genes. However, the function of BAF53A in the androgen receptor pathway in prostate cancer cells remains unclear. Here, we demonstrated that BAF53A positively regulates the expression of endogenous AR target genes (e.g. PSA, TMPRSS2, FKBP5, and KLK2) in LNCaP cells. It functions as a coactivator in AR-mediated transcription by interacting with other nuclear receptor coactivators, such as p300 and FLII, and is associated with AR in the presence of dihydrotestosterone (DHT). The DHT-induced recruitment of BAF53A to the proximal and distal androgen response elements (AREs) of the PSA gene in the presence of BRG1 (but not BRM) was inhibited by an AR antagonist, suggesting the coactivator function of BAF53A in the SWI/SNF complex. Depletion of BAF53A in LNCaP cells resulted in a significant decrease in growth rate. Furthermore, the expression of BAF53A in prostate cancer tissue was significantly elevated, compared to that in normal prostate tissue, and correlated with the expression of AR, and BRG1, but not BRM. Therefore, our results suggested that BAF53A plays an important role in the expression of AR target genes in prostate cancer, and can be used clinically for the treatment of prostate cancer.
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Affiliation(s)
- Ming Li Jin
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea
| | - Young Woong Kim
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea
| | - Kwang Won Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea.
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Xia D, Lai DV, Wu W, Webb ZD, Yang Q, Zhao L, Yu Z, Thorpe JE, Disch BC, Ihnat MA, Jayaraman M, Dhanasekaran DN, Stratton KL, Cookson MS, Fung KM, Lin HK. Transition from androgenic to neurosteroidal action of 5α-androstane-3α, 17β-diol through the type A γ-aminobutyric acid receptor in prostate cancer progression. J Steroid Biochem Mol Biol 2018; 178:89-98. [PMID: 29155210 DOI: 10.1016/j.jsbmb.2017.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/10/2017] [Accepted: 11/14/2017] [Indexed: 02/07/2023]
Abstract
Androgen ablation is the standard of care prescribed to patients with advanced or metastatic prostate cancer (PCa) to slow down disease progression. Unfortunately, a majority of PCa patients under androgen ablation progress to castration-resistant prostate cancer (CRPC). Several mechanisms including alternative intra-prostatic androgen production and androgen-independent androgen receptor (AR) activation have been proposed for CRPC progression. Aldo-keto reductase family 1 member C3 (AKR1C3), a multi-functional steroid metabolizing enzyme, is specifically expressed in the cytoplasm of PCa cells; and positive immunoreactivity of the type A γ-aminobutyric acid receptor (GABAAR), an ionotropic receptor and ligand-gated ion channel, is detected on the membrane of PCa cells. We studied a total of 72 radical prostatectomy cases by immunohistochemistry, and identified that 21 cases exhibited positive immunoreactivities for both AKR1C3 and GABAAR. In the dual positive cancer cases, AKR1C3 and GABAAR subunit α1 were either expressed in the same cells or in neighboring cells. Among several possible substrates, AKR1C3 reduces 5α-dihydrotesterone (DHT) to form 5α-androstane-3α, 17β-diol (3α-diol). 3α-diol is a neurosteroid that acts as a positive allosteric modulator of the GABAAR in the central nervous system (CNS). We examined the hypothesis that 3α-diol-regulated pathological effects in the prostate are GABAAR-dependent, but are independent of the AR. In GABAAR-positive, AR-negative human PCa PC-3 cells, 3α-diol significantly stimulated cell growth in culture and the in ovo chorioallantoic membrane (CAM) xenograft model. 3α-diol also up-regulated expression of the epidermal growth factor (EGF) family of growth factors and activation of EGF receptor (EGFR) and Src as measured by quantitative polymerase chain reaction and immunoblotting, respectively. Inclusion of GABAAR antagonists reversed 3α-diol-stimulated tumor cell growth, expression of EGF family members, and activation of EGFR and Src to the level observed in untreated cells. Results from the present study suggest that 3α-diol may act as an alternative intra-prostatic neurosteroid that activates AR-independent PCa progression. The involvement of AKR1C3-mediated steroid metabolisms in modulating GABAAR activation and promoting PCa progression requires continued studies.
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Affiliation(s)
- Ding Xia
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China; Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Doan V Lai
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Weijuan Wu
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zachary D Webb
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Qing Yang
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Lichao Zhao
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zhongxin Yu
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jessica E Thorpe
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma College of Pharmacy, OKC, OK 73117, USA
| | - Bryan C Disch
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma College of Pharmacy, OKC, OK 73117, USA
| | - Michael A Ihnat
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma College of Pharmacy, OKC, OK 73117, USA
| | | | - Danny N Dhanasekaran
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Kelly L Stratton
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Michael S Cookson
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Kar-Ming Fung
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Pathology, Veterans Affairs Medical Center, Oklahoma City, Oklahoma, OK 73104, USA
| | - Hsueh-Kung Lin
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Yu P, Duan X, Cheng Y, Liu C, Chen Y, Liu W, Yin B, Wang X, Tao Z. Androgen-independent LNCaP cells are a subline of LNCaP cells with a more aggressive phenotype and androgen suppresses their growth by inducing cell cycle arrest at the G1 phase. Int J Mol Med 2017; 40:1426-1434. [PMID: 28901378 PMCID: PMC5627872 DOI: 10.3892/ijmm.2017.3125] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 08/17/2017] [Indexed: 11/06/2022] Open
Abstract
Androgen deprivation therapy (ADT, surgical or chemical castration) is the mainstay treatment for metastatic prostate cancer (PCa); however, patients ineluctably relapse despite extremely low androgen levels. This evolution of PCa indicates its lethal progression. In this study, to mimic the traits of clinical PCa progression in vitro, we investigated the alterations in the cell biological characteristics in androgen-independent LNCaP cells (LNCaP-AI cells) compared with LNCaP cells. We also examined the effects of androgen on LNCaP and LNCaP-AI cell proliferation, androgen receptor (AR) expression and prostate-specific antigen (PSA) secretion. Furthermore, AR was silenced in the LNCaP and LNCaP-AI cells to detect the roles taht AR plays in cell growth, apoptosis and PSA secretion. We found that prolonged androgen ablation increased the LNCaP-AI cell growth rate and cell invasiveness, and induced epithelial-mesenchymal transition in the LNCaP-AI cells. Moreover, despite the fact that the LNCaP and LNCaP-AI cells expressed equal amounts of AR protein, androgen induced a greater secretion of PSA in the LNCaP-AI cells than in the LNCaP cells. The proliferation of the LNCaP-AI cells was not dependent on, but was suppressed by androgen, which led to arrest at the G1 phase. Conversely, androgen significantly increased LNCaP cell proliferation by promoting the G1-S transition. Moreover, the silencing of AR suppressed LNCaP and LNCaP-AI cell growth by inducing cell cycle arrest at the G1 phase rather than promoting apoptosis, and reduced PSA secretion. On the whole, our data suggest that LNCaP-AI cells have a more more aggressive phenotype compared with the LNCaP cells; AR remains a critical factor in the LNCaP-AI cells, and androgen suppresses LNCaP-AI cell growth by blocking the cell cycle at the G1 phase.
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Affiliation(s)
- Pan Yu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Xiuzhi Duan
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Yue Cheng
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Chunhua Liu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Yuhua Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Weiwei Liu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Binbin Yin
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Xuchu Wang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Zhihua Tao
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
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Ajiboye AS, Esopi D, Yegnasubramanian S, Denmeade SR. Androgen Receptor Splice Variants Are Not Substrates of Nonsense-Mediated Decay. Prostate 2017; 77:829-837. [PMID: 28224650 PMCID: PMC5400682 DOI: 10.1002/pros.23323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 01/23/2017] [Indexed: 01/24/2023]
Abstract
BACKGROUND Androgen receptor (AR) splice variants have been clinically associated with progressive cancer, castration-resistance, and resistance to AR antagonists and androgen synthesis inhibitors. AR variants can be generated by genomic alterations and alternative splicing, and their expression is androgen-regulated. There has been a suggestion that AR variants bearing premature termination codons and coding for truncated proteins should be regulated by the nonsense-mediated decay (NMD) mRNA surveillance pathway, suggesting that either the NMD pathway is dysfunctional in variant-expressing cell lines or that variants are somehow able to evade degradation by NMD. METHODS We first used siRNA knockdown of the NMD regulator, UPF1, in an NMD reporter assay to determine if this surveillance pathway is functioning normally in AR variant-expressing cell lines. We then used UPF1 knockdown to determine if expression of the AR variants ARV3 and ARV7 is affected by inhibition of NMD. Next, we analyzed androgen regulation of UPF1 and used transcript expression analysis to determine if there is any association between UPF1 expression, resistance, and ARV3 or ARV7 expression. RESULTS We found that the NMD pathway functions normally in the AR variant-expressing cell line 22Rv1 and that inhibition of NMD does not increase expression of ARV3 or ARV7. Furthermore, we found that expression of UPF1 is not androgen-regulated. We also found that UFP1 expression levels do not differentiate castration-sensitive from resistant cell line and that UPF1 expression does not correlate with expression of ARV3 or ARV7 in cells in which these variants are highly expressed. CONCLUSION This study eliminates a possible mechanism of regulation of certain AR variants. Future research into the regulation of AR variants should focus on other mechanisms to better understand the origin of these variants and to possibly inhibit their expression for the resensitization of resistant cancers. Prostate 77:829-837, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- A. Seun Ajiboye
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - David Esopi
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland
| | - Srinivasan Yegnasubramanian
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland
| | - Samuel R. Denmeade
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland
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11
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Fajardo AM, MacKenzie DA, Olguin SL, Scariano JK, Rabinowitz I, Thompson TA. Antioxidants Abrogate Alpha-Tocopherylquinone-Mediated Down-Regulation of the Androgen Receptor in Androgen-Responsive Prostate Cancer Cells. PLoS One 2016; 11:e0151525. [PMID: 26986969 PMCID: PMC4795544 DOI: 10.1371/journal.pone.0151525] [Citation(s) in RCA: 10] [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: 10/21/2015] [Accepted: 02/28/2016] [Indexed: 01/27/2023] Open
Abstract
Tocopherylquinone (TQ), the oxidation product of alpha-tocopherol (AT), is a bioactive molecule with distinct properties from AT. In this study, AT and TQ are investigated for their comparative effects on growth and androgenic activity in prostate cancer cells. TQ potently inhibited the growth of androgen-responsive prostate cancer cell lines (e.g., LAPC4 and LNCaP cells), whereas the growth of androgen-independent prostate cancer cells (e.g., DU145 cells) was not affected by TQ. Due to the growth inhibitory effects induced by TQ on androgen-responsive cells, the anti-androgenic properties of TQ were examined. TQ inhibited the androgen-induced activation of an androgen-responsive reporter and inhibited the release of prostate specific antigen from LNCaP cells. TQ pretreatment was also found to inhibit AR activation as measured using the Multifunctional Androgen Receptor Screening assay. Furthermore, TQ decreased androgen-responsive gene expression, including TM4SF1, KLK2, and PSA over 5-fold, whereas AT did not affect the expression of androgen-responsive genes. Of importance, the antiandrogenic effects of TQ on prostate cancer cells were found to result from androgen receptor protein down-regulation produced by TQ that was not observed with AT treatment. Moreover, none of the androgenic endpoints assessed were affected by AT. The down-regulation of androgen receptor protein by TQ was abrogated by co-treatment with antioxidants. Overall, the biological actions of TQ were found to be distinct from AT, where TQ was found to be a potent inhibitor of cell growth and androgenic activity in androgen-responsive prostate cancer cells.
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Affiliation(s)
- Alexandra M. Fajardo
- Department of Pharmaceutical Sciences, University of New Mexico College of Pharmacy, Albuquerque, New Mexico, United States of America
| | - Debra A. MacKenzie
- Department of Pharmaceutical Sciences, University of New Mexico College of Pharmacy, Albuquerque, New Mexico, United States of America
| | - Sarah L. Olguin
- Department of Pharmaceutical Sciences, University of New Mexico College of Pharmacy, Albuquerque, New Mexico, United States of America
| | - John K. Scariano
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Ian Rabinowitz
- Division of Hematology/Oncology, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Todd A. Thompson
- Department of Pharmaceutical Sciences, University of New Mexico College of Pharmacy, Albuquerque, New Mexico, United States of America
- University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico, United States of America
- * E-mail:
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12
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Vander Griend DJ, Litvinov IV, Isaacs JT. Conversion of androgen receptor signaling from a growth suppressor in normal prostate epithelial cells to an oncogene in prostate cancer cells involves a gain of function in c-Myc regulation. Int J Biol Sci 2014; 10:627-42. [PMID: 24948876 PMCID: PMC4062956 DOI: 10.7150/ijbs.8756] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/12/2014] [Indexed: 12/22/2022] Open
Abstract
In normal prostate, androgen-dependent androgen receptor (AR) signaling within prostate stromal cells induces their secretion of paracrine factors, termed “andromedins” which stimulate growth of the epithelial cells. The present studies demonstrate that androgen-dependent andromedin-driven growth stimulation is counter-balanced by androgen-induced AR signaling within normal adult prostate epithelial cells resulting in terminal G0 growth arrest coupled with terminal differentiation into ΔNp63-negative, PSA-expressing secretory luminal cells. This cell autonomous AR-driven terminal differentiation requires DNA-binding of the AR protein, is associated with decreases in c-Myc m-RNA and protein, are coupled with increases in p21, p27, and SKP-2 protein expression, and does not require functional p53. These changes result in down-regulation of Cyclin D1 protein and RB phosphoryation. shRNA knockdown documents that neither RB, p21, p27 alone or in combination are required for such AR-induced G0 growth arrest. Transgenic expression of a constitutive vector to prevent c-Myc down-regulation overrides AR-mediated growth arrest in normal prostate epithelial cells, which documents that AR-induced c-Myc down-regulation is critical in terminal growth arrest of normal prostate epithelial cells. In contrast, in prostate cancer cells, androgen-induced AR signaling paradoxically up-regulates c-Myc expression and stimulates growth as documented by inhibition of both of these responses following exposure to the AR antagonist, bicalutamide. These data document that AR signaling is converted from a growth suppressor in normal prostate epithelial cells to an oncogene in prostate cancer cells during prostatic carcinogenesis and that this conversion involves a gain of function for regulation of c-Myc expression.
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Affiliation(s)
- Donald J Vander Griend
- 1. Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. ; 3. The Brady Urological Institute, Johns Hopkins
| | - Ivan V Litvinov
- 1. Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. ; 2. Cellular and Molecular Medicine Graduate Program at Johns Hopkins
| | - John T Isaacs
- 1. Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. ; 2. Cellular and Molecular Medicine Graduate Program at Johns Hopkins. ; 3. The Brady Urological Institute, Johns Hopkins
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13
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Bauman TM, Sehgal PD, Johnson KA, Pier T, Bruskewitz RC, Ricke WA, Huang W. Finasteride treatment alters tissue specific androgen receptor expression in prostate tissues. Prostate 2014; 74:923-32. [PMID: 24789081 PMCID: PMC4137476 DOI: 10.1002/pros.22810] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/20/2014] [Indexed: 12/31/2022]
Abstract
BACKGROUND Normal and pathologic growth of the prostate is dependent on the synthesis of dihydrotestosterone (DHT) from testosterone by 5α-reductase. Finasteride is a selective inhibitor of 5α-reductase 2, one isozyme of 5α-reductase found in abundance in the human prostate. The objective of this study was to investigate the effects of finasteride on androgen receptor expression and tissue morphology in human benign prostatic hyperplasia specimens. METHODS Patients undergoing transurethral resection of the prostate and either treated or not treated with finasteride between 2004 and 2010 at the University of Wisconsin-Hospital were retrospectively identified using an institutional database. Prostate specimens from each patient were triple-stained for androgen receptor, prostate-specific antigen, and basal marker cytokeratin 5. Morphometric analysis was performed using the multispectral imaging, and results were compared between groups of finasteride treated and non-treated patients. RESULTS Epithelial androgen receptor but not stromal androgen receptor expression was significantly lower in patients treated with finasteride than in non-treated patients. Androgen receptor-regulated prostate-specific antigen was not significantly decreased in finasteride-treated patients. Significant luminal epithelial atrophy and basal cell hyperplasia were prevalent in finasteride treated patients. Epithelial androgen receptor expression was highly correlated to the level of luminal epithelial atrophy. CONCLUSIONS In this study, finasteride decreased the expression of epithelial androgen receptor in a tissue specific manner. The correlation between epithelial androgen receptor and the extent of luminal epithelial atrophy suggests that epithelial androgen receptor may be directly regulating the atrophic effects observed with finasteride treatment.
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Affiliation(s)
- Tyler M. Bauman
- Department of Urology, University of Wisconsin, Madison, Wisconsin
| | | | - Karen A. Johnson
- Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
| | - Thomas Pier
- Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
| | | | - William A. Ricke
- Department of Urology, University of Wisconsin, Madison, Wisconsin
- Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin
- Correspondence to: William A. Ricke, PhD, Department of Urology and Carbone Cancer Center, University of Wisconsin, 7107 Wisconsin Institutes of Medical Research (WIMR), 1111 Highland Ave., Madison, WI 53705.
| | - Wei Huang
- Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
- Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin
- Correspondence to: Wei Huang, MD, Department of Pathology and Laboratory Medicine and Carbone Cancer Center, University of Wisconsin, 1685 Highland Ave., Madison, WI 53705.
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14
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Fitzgerald KA, Evans JC, McCarthy J, Guo J, Prencipe M, Kearney M, Watson WR, O'Driscoll CM. The role of transcription factors in prostate cancer and potential for future RNA interference therapy. Expert Opin Ther Targets 2014; 18:633-49. [DOI: 10.1517/14728222.2014.896904] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Felgueiras J, Silva JV, Fardilha M. Prostate cancer: the need for biomarkers and new therapeutic targets. J Zhejiang Univ Sci B 2014; 15:16-42. [PMID: 24390742 PMCID: PMC3891116 DOI: 10.1631/jzus.b1300106] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 06/08/2013] [Indexed: 12/16/2022]
Abstract
Prostate cancer (PCa) incidence and mortality have decreased in recent years. Nonetheless, it remains one of the most prevalent cancers in men, being a disquieting cause of men's death worldwide. Changes in many cell signaling pathways have a predominant role in the onset, development, and progression of the disease. These include prominent pathways involved in the growth, apoptosis, and angiogenesis of the normal prostate gland, such as androgen and estrogen signaling, and other growth factor signaling pathways. Understanding the foundations of PCa is leading to the discovery of key molecules that could be used to improve patient management. The ideal scenario would be to have a panel of molecules, preferably detectable in body fluids, that are specific and sensitive biomarkers for PCa. In the early stages, androgen deprivation is the gold standard therapy. However, as the cancer progresses, it eventually becomes independent of androgens, and hormonal therapy fails. For this reason, androgen-independent PCa is still a major therapeutic challenge. By disrupting specific protein interactions or manipulating the expression of some key molecules, it might be possible to regulate tumor growth and metastasis formation, avoiding the systemic side effects of current therapies. Clinical trials are already underway to assess the efficacy of molecules specially designed to target key proteins or protein interactions. In this review, we address that recent progress made towards understanding PCa development and the molecular pathways underlying this pathology. We also discuss relevant molecular markers for the management of PCa and new therapeutic challenges.
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16
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Masoodi KZ, Ramos Garcia R, Pascal LE, Wang Y, Ma HM, O'Malley K, Eisermann K, Shevrin DH, Nguyen HM, Vessella RL, Nelson JB, Parikh RA, Wang Z. 5α-reductase inhibition suppresses testosterone-induced initial regrowth of regressed xenograft prostate tumors in animal models. Endocrinology 2013; 154:2296-307. [PMID: 23671262 PMCID: PMC3689274 DOI: 10.1210/en.2012-2077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Androgen deprivation therapy (ADT) is the standard treatment for patients with prostate-specific antigen progression after treatment for localized prostate cancer. An alternative to continuous ADT is intermittent ADT (IADT), which allows recovery of testosterone during off-cycles to stimulate regrowth and differentiation of the regressed prostate tumor. IADT offers patients a reduction in side effects associated with ADT, improved quality of life, and reduced cost with no difference in overall survival. Our previous studies showed that IADT coupled with 5α-reductase inhibitor (5ARI), which blocks testosterone conversion to DHT could prolong survival of animals bearing androgen-sensitive prostate tumors when off-cycle duration was fixed. To further investigate this clinically relevant observation, we measured the time course of testosterone-induced regrowth of regressed LuCaP35 and LNCaP xenograft tumors in the presence or absence of a 5ARI. 5α-Reductase inhibitors suppressed the initial regrowth of regressed prostate tumors. However, tumors resumed growth and were no longer responsive to 5α-reductase inhibition several days after testosterone replacement. This finding was substantiated by bromodeoxyuridine and Ki67 staining of LuCaP35 tumors, which showed inhibition of prostate tumor cell proliferation by 5ARI on day 2, but not day 14, after testosterone replacement. 5α-Reductase inhibitors also suppressed testosterone-stimulated proliferation of LNCaP cells precultured in androgen-free media, suggesting that blocking testosterone conversion to DHT can inhibit prostate tumor cell proliferation via an intracrine mechanism. These results suggest that short off-cycle coupled with 5α-reductase inhibition could maximize suppression of prostate tumor growth and, thus, improve potential survival benefit achieved in combination with IADT.
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Affiliation(s)
- Khalid Z Masoodi
- Department of Urology, Hillman Cancer Centre, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, USA
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17
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Eder IE, Egger M, Neuwirt H, Seifarth C, Maddalo D, Desiniotis A, Schäfer G, Puhr M, Bektic J, Cato ACB, Klocker H. Enhanced inhibition of prostate tumor growth by dual targeting the androgen receptor and the regulatory subunit type iα of protein kinase a in vivo. Int J Mol Sci 2013; 14:11942-62. [PMID: 23736698 PMCID: PMC3709765 DOI: 10.3390/ijms140611942] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/29/2013] [Accepted: 05/29/2013] [Indexed: 12/02/2022] Open
Abstract
Progression to castration resistance is a major problem in the treatment of advanced prostate cancer and is likely to be driven by activation of several molecular pathways, including androgen receptor (AR) and cyclic AMP-dependent protein kinase A (PKA). In this study, we examined the therapeutic efficacy of a combined inhibition of the AR and the regulatory subunit type Iα (RIα) of protein kinase A with second generation antisense oligonucleotides (ODNs) in androgen-sensitive LNCaP and castration-resistant LNCaPabl tumors in vivo. We found that targeting the AR alone inhibited LNCaP, as well as LNCaPabl tumors. Combined inhibition resulted in an improved response over single targeting and even a complete tumor remission in LNCaPabl. Western blot analysis revealed that both ODNs were effective in reducing their target proteins when administered alone or in combination. In addition, treatment with the ODNs was associated with an induction of apoptosis. Our data suggest that dual targeting of the AR and PKARIα is more effective in inhibiting LNCaP and LNCaPabl tumor growth than single treatment and may give a treatment benefit, especially in castration-resistant prostate cancers.
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Affiliation(s)
- Iris E. Eder
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +43-512-504-24819; Fax: +43-512-504-24817
| | - Martina Egger
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
| | - Hannes Neuwirt
- Department of Internal Medicine IV—Nephrology and Hypertension, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mail:
| | - Christof Seifarth
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
- Oncotyrol Center for Personalized Cancer Medicine GmbH, Karl-Kapferer-Straße 5, 6020 Innsbruck, Austria
| | - Danilo Maddalo
- Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Toxicology and Genetics, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany; E-Mails: (D.M.); (A.C.B.C.)
| | - Andreas Desiniotis
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
| | - Georg Schäfer
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
| | - Martin Puhr
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
| | - Jasmin Bektic
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
| | - Andrew C. B. Cato
- Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Toxicology and Genetics, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany; E-Mails: (D.M.); (A.C.B.C.)
| | - Helmut Klocker
- Division of Experimental Urology, Innsbruck Medical University, 6020 Innsbruck, Anichstraße 35, Austria; E-Mails: (M.E.); (C.S.); (A.D.); (G.S.); (M.P.); (J.B.); (H.K.)
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Ebron JS, Weyman CM, Shukla GC. Targeting of Androgen Receptor Expression by Andro-miRs as Novel Adjunctive Therapeutics in Prostate Cancer. ACTA ACUST UNITED AC 2013; 4:47-58. [PMID: 26877888 PMCID: PMC4751888 DOI: 10.4236/jct.2013.44a006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Prostate cancer begins as an androgen-responsive disease. However, subsequent accumulation of multiple sequential genetic and epigenetic alterations transforms the disease into an aggressive, castration-resistant prostate cancer (CRPC). The monoallelic Androgen Receptor (AR) is associated with the onset, growth and development of Prostate cancer. The AR is a ligand-dependent transcription factor, and the targeting of androgen- and AR-signaling axis remains the primary therapeutic option for Prostate cancer (PCa) treatment. A durable and functional disruption of AR signaling pathways combining both traditional and novel therapeutics is likely to provide better treatment options for CRPC. Recent work has indicated that expression of AR is modulated at the posttranscriptional level by regulatory miRNAs. Due to a relatively long 3’ untranslated region (UTR) of AR mRNA, the posttranscription expression is likely to be regulated by hundreds of miRNAs in normal as well as in disease state. The main objective of the article is to offer a thought-provoking concept of “andro-miRs” and their potential application in AR gene expression targeting. This new paradigm for targeting constitutively active AR and its tumor specific splicing isoforms using andro-miRs may pave the way for a novel adjunctive therapy and improved treatment of CRPC.
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Affiliation(s)
- Jey Sabith Ebron
- Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, USA
| | - Crystal M Weyman
- Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, USA; Department of Biological, Environmental Sciences, Cleveland State University, Cleveland, USA
| | - Girish C Shukla
- Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, USA; Department of Biological, Environmental Sciences, Cleveland State University, Cleveland, USA
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19
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Integration of regulatory networks by NKX3-1 promotes androgen-dependent prostate cancer survival. Mol Cell Biol 2011; 32:399-414. [PMID: 22083957 DOI: 10.1128/mcb.05958-11] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The NKX3-1 gene is a homeobox gene required for prostate tumor progression, but how it functions is unclear. Here, using chromatin immunoprecipitation coupled to massively parallel sequencing (ChIP-seq) we showed that NKX3-1 colocalizes with the androgen receptor (AR) across the prostate cancer genome. We uncovered two distinct mechanisms by which NKX3-1 controls the AR transcriptional network in prostate cancer. First, NKX3-1 and AR directly regulate each other in a feed-forward regulatory loop. Second, NKX3-1 collaborates with AR and FoxA1 to mediate genes in advanced and recurrent prostate carcinoma. NKX3-1- and AR-coregulated genes include those found in the "protein trafficking" process, which integrates oncogenic signaling pathways. Moreover, we demonstrate that NKX3-1, AR, and FoxA1 promote prostate cancer cell survival by directly upregulating RAB3B, a member of the RAB GTPase family. Finally, we show that RAB3B is overexpressed in prostate cancer patients, suggesting that RAB3B together with AR, FoxA1, and NKX3-1 are important regulators of prostate cancer progression. Collectively, our work highlights a novel hierarchical transcriptional regulatory network between NKX3-1, AR, and the RAB GTPase signaling pathway that is critical for the genetic-molecular-phenotypic paradigm in androgen-dependent prostate cancer.
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20
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Sikand K, Slaibi JE, Singh R, Slane SD, Shukla GC. miR 488* inhibits androgen receptor expression in prostate carcinoma cells. Int J Cancer 2011; 129:810-9. [PMID: 21710544 PMCID: PMC3839820 DOI: 10.1002/ijc.25753] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Androgen receptor (AR) is a ligand-dependent transcription factor, which plays a significant role in prostate carcinogenesis. Blockade of AR and its ligand, androgen is the basis for the treatment of prostate cancer (PCa). Nevertheless, a modest increase in the critical levels of AR mRNA and corresponding protein is sufficient for the development of resistance to antiandrogen therapy. A strategy to further downregulate AR mRNA and protein expression in combination with antiandrogen therapy may prevent or delay the development of androgen-independent PCa. Recent studies show that microRNAs (miRNAs) perform tumor suppressor functions in various cancers. In this study, we demonstrate that the overexpression of miR 488* downregulates the transcriptional activity of AR and inhibits the endogenous AR protein production in both androgen-dependent and androgen-independent PCa cells. In addition, miR 488* blocks the proliferation and enhances the apoptosis of PCa cells. Our data indicate that miR 488* targets AR and is a potential modulator of AR mediated signaling. Our findings provide insight for utilizing miRNAs as novel therapeutics to target AR in PCa.
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Affiliation(s)
- Kavleen Sikand
- Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
| | - Jinani E. Slaibi
- Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
| | - Rajesh Singh
- Department of Microbiology, Biochemistry and Immunology, Cell and Tissue Imaging Core, Morehouse School of Medicine, Atlanta, GA
| | - Stephen D. Slane
- Department of Psychology, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
| | - Girish C. Shukla
- Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH
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21
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CD8+ T cells specific for the androgen receptor are common in patients with prostate cancer and are able to lyse prostate tumor cells. Cancer Immunol Immunother 2011; 60:781-92. [PMID: 21350948 DOI: 10.1007/s00262-011-0987-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 02/06/2011] [Indexed: 12/29/2022]
Abstract
The androgen receptor (AR) is a hormone receptor that plays a critical role in prostate cancer, and depletion of its ligand has long been the cornerstone of treatment for metastatic disease. Here, we evaluate the AR ligand-binding domain (LBD) as an immunological target, seeking to identify HLA-A2-restricted epitopes recognized by T cells in prostate cancer patients. Ten AR LBD-derived, HLA-A2-binding peptides were identified and ranked with respect to HLA-A2 affinity and were used to culture peptide-specific T cells from HLA-A2+ prostate cancer patients. These T-cell cultures identified peptide-specific T cells specific for all ten peptides in at least one patient, and T cells specific for peptides AR805 and AR811 were detected in over half of patients. Peptide-specific CD8+ T-cell clones were then isolated and characterized for prostate cancer cytotoxicity and cytokine expression, identifying that AR805 and AR811 CD8+ T-cell clones could lyse prostate cancer cells in an HLA-A2-restricted fashion, but only AR811 CTL had polyfunctional cytokine expression. Epitopes were confirmed using immunization studies in HLA-A2 transgenic mice, in which the AR LBD is an autologous antigen with an identical protein sequence, which showed that mice immunized with AR811 developed peptide-specific CTL that lyse HLA-A2+ prostate cancer cells. These data show that AR805 and AR811 are HLA-A2-restricted epitopes for which CTL can be commonly detected in prostate cancer patients. Moreover, CTL responses specific for AR811 can be elicited by direct immunization of A2/DR1 mice. These findings suggest that it may be possible to elicit an anti-prostate tumor immune response by augmenting CTL populations using AR LBD-based vaccines.
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22
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Lamb LE, Zarif JC, Miranti CK. The androgen receptor induces integrin α6β1 to promote prostate tumor cell survival via NF-κB and Bcl-xL Independently of PI3K signaling. Cancer Res 2011; 71:2739-49. [PMID: 21310825 DOI: 10.1158/0008-5472.can-10-2745] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent studies indicate that androgen receptor (AR) signaling is critical for prostate cancer cell survival, even in castration-resistant disease wherein AR continues to function independently of exogenous androgens. Integrin-mediated adhesion to the extracellular matrix is also important for prostate cell survival. AR-positive prostate cancer cells express primarily integrin α6β1 and adhere to a laminin-rich matrix. In this study, we show that active nuclear-localized AR protects prostate cancer cells from death induced by phosphoinositide 3-kinase (PI3K) inhibition when cells adhere to laminin. Resistance to PI3K inhibition is mediated directly by an AR-dependent increase in integrin α6β1 mRNA transcription and protein expression. Subsequent signaling by integrin α6β1 in AR-expressing cells increased NF-κB activation and Bcl-xL expression. Blocking AR, integrin α6, NF-κB, or Bcl-xL concurrent with inhibition of PI3K was sufficient and necessary to trigger death of laminin-adherent AR-expressing cells. Taken together, these results define a novel integrin-dependent survival pathway in prostate cancer cells that is regulated by AR, independent of and parallel to the PI3K pathway. Our findings suggest that combined targeting of both the AR/α6β1 and PI3K pathways may effectively trigger prostate cancer cell death, enhancing the potential therapeutic value of PI3K inhibitors being evaluated in this setting.
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Affiliation(s)
- Laura E Lamb
- Laboratory of Integrin Signaling and Tumorigenesis, Van Andel Research Institute, Grand Rapids, Michigan State University, East Lansing, Michigan, USA
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Lund TD, Blake C, Bu L, Hamaker AN, Lephart ED. Equol an isoflavonoid: potential for improved prostate health, in vitro and in vivo evidence. Reprod Biol Endocrinol 2011; 9:4. [PMID: 21232127 PMCID: PMC3032666 DOI: 10.1186/1477-7827-9-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 01/13/2011] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND To determine: in vitro binding affinity of equol for 5alpha-dihydrotestosterone (5alpha-DHT), in vitro effects of equol treatment in human prostate cancer (LNCap) cells, and in vivo effects of equol on rat prostate weight and circulating levels of sex steroid hormones. METHODS First, in vitro equol binding affinity for 5alpha-DHT was determined using 14C5alpha-DHT combined with cold 5alpha-DHT (3.0 nM in all samples). These steroids were incubated with increasing concentrations of equol (0-2,000 nM) and analyzed by Sephadex LH-20 column chromatography. 14C5alpha-DHT peak/profiles were determined by scintillation counting of column fractions. Using the 14C5alpha-DHT peak (0 nM equol) as a reference standard, a binding curve was generated by quantifying shifts in the 14C5alpha-DHT peaks as equol concentrations increased. Second, equol's in vitro effects on LNCap cells were determined by culturing cells (48 hours) in the presence of increasing concentrations of dimethyl sulfoxide (DMSO) (vehicle-control), 5alpha-DHT, equol or 5alpha-DHT+equol. Following culture, prostate specific antigen (PSA) levels were quantified via ELISA. Finally, the in vivo effects of equol were tested in sixteen male Long-Evans rats fed a low isoflavone diet. From 190-215 days, animals received 0.1 cc s.c. injections of either DMSO-control vehicle (n = 8) or 1.0 mg/kg (body weight) of equol (in DMSO) (n = 8). At 215 days, body and prostate weights were recorded, trunk blood was collected and serum assayed for luteinizing hormone (LH), 5alpha-DHT, testosterone and 17beta-estradiol levels. RESULTS Maximum and half maximal equol binding to 5alpha-DHT occurred at approximately 100 nM and 4.8 nM respectively. LNCap cells cultured in the presence of 5alpha-DHT significantly increased PSA levels. However, in the presence of 5alpha-DHT+equol, equol blocked the significant increases in PSA levels from LNCap cells. In vivo equol treatment significantly decreased rat prostate weights and serum 5alpha-DHT levels but did not alter LH, testosterone, and estradiol levels. CONCLUSIONS Equol administration appears to have potential beneficial effects for prostate health and other 5alpha-DHT mediated disorders. Equol administration: reduces PSA levels from LNCap cells under 5alpha-DHT stimulation, decreases rat prostate size, decreases serum 5alpha-DHT levels and androgen hormone action, while not altering other circulating sex steroids or LH levels.
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Affiliation(s)
| | - Crystal Blake
- The Department of Physiology and Developmental Biology and the Neuroscience Center, Brigham Young University, Provo, Utah 84602, USA
| | - Lihong Bu
- MRDDRC Imaging Core, Department of Neurobiology, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA
| | - Amy N Hamaker
- The Department of Physiology and Developmental Biology and the Neuroscience Center, Brigham Young University, Provo, Utah 84602, USA
| | - Edwin D Lephart
- The Department of Physiology and Developmental Biology and the Neuroscience Center, Brigham Young University, Provo, Utah 84602, USA
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Loss of androgen receptor-dependent growth suppression by prostate cancer cells can occur independently from acquiring oncogenic addiction to androgen receptor signaling. PLoS One 2010; 5:e11475. [PMID: 20628607 PMCID: PMC2900211 DOI: 10.1371/journal.pone.0011475] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 06/14/2010] [Indexed: 11/19/2022] Open
Abstract
The conversion of androgen receptor (AR) signaling as a mechanism of growth suppression of normal prostate epithelial cells to that of growth stimulation in prostate cancer cells is often associated with AR mutation, amplification and over-expression. Thus, down-regulation of AR signaling is commonly therapeutic for prostate cancer. The E006AA cell line was established from a hormone naïve, localized prostate cancer. E006AA cells are genetically aneuploid and grow equally well when xenografted into either intact or castrated male NOG but not nude mice. These cells exhibit: 1) X chromosome duplication and AR gene amplification, although paradoxically not coupled with increased AR expression, and 2) somatic, dominant-negative Serine-599-Glycine loss-of-function mutation within the dimerization surface of the DNA binding domain of the AR gene. No effect on the growth of E006AA cells is observed using targeted knockdown of endogenous mutant AR, ectopic expression of wild-type AR, or treatment with androgens or anti-androgens. E006AA cells represent a prototype for a newly identified subtype of prostate cancer cells that exhibit a dominant-negative AR loss-of-function in a hormonally naïve patient. Such loss-of-function eliminates AR-mediated growth suppression normally induced by normal physiological levels of androgens, thus producing a selective growth advantage for these malignant cells in hormonally naïve patients. These data highlight that loss of AR-mediated growth suppression is an independent process, and that, without additional changes, is insufficient for acquiring oncogene addiction to AR signaling. Thus, patients with prostate cancer cells harboring such AR loss-of-function mutations will not benefit from aggressive hormone or anti-AR therapies even though they express AR protein.
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Rajamahanty S, Alonzo C, Aynehchi S, Choudhury M, Konno S. Growth inhibition of androgen-responsive prostate cancer cells with brefeldin A targeting cell cycle and androgen receptor. J Biomed Sci 2010; 17:5. [PMID: 20102617 PMCID: PMC2843609 DOI: 10.1186/1423-0127-17-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 01/26/2010] [Indexed: 11/28/2022] Open
Abstract
Background Androgen ablation is one of the viable therapeutic options for patients with primary hormone (androgen)-dependent prostate cancer. However, an antibiotic brefeldin A (BFA) has been shown to exhibit the growth inhibitory effect on human cancer cells. We thus investigated if BFA might inhibit proliferation of androgen-responsive prostate cancer LNCaP cells and also explored how it would be carried out, focusing on cell cycle and androgen receptor (AR). Methods Androgen-mediated cellular events in LNCaP cells were induced using 5α-dihydrotestosterone (DHT) as an androgenic mediator. Effects of BFA on non-DHT-stimulated or DHT-stimulated cell growth were assessed. Its growth inhibitory mechanism(s) was further explored; performing cell cycle analysis on a flow cytometer, assessing AR activity by AR binding assay, and analyzing AR protein expression using Western blot analysis. Results DHT (1 nM) was capable of stimulating LNCaP cell growth by ~40% greater than non-stimulated controls, whereas BFA (30 ng/ml) completely inhibited such DHT-stimulated proliferation. Cell cycle analysis showed that this BFA-induced growth inhibition was associated with a ~75% reduction in the cell number in the S phase and a concomitant increase in the G1 cell number, indicating a G1 cell cycle arrest. This was further confirmed by the modulations of specific cell cycle regulators (CDK2, CDK4, cyclin D1, and p21WAF1), revealed by Western blots. In addition, the growth inhibition induced by BFA was accompanied by a profound (~90%) loss in AR activity, which would be presumably attributed to the significantly reduced cellular AR protein level. Conclusions This study demonstrates that BFA has a potent growth inhibitory activity, capable of completely inhibiting DHT (androgen)-stimulated LNCaP proliferation. Such inhibitory action of BFA appears to target cell cycle and AR: BFA led to a G1 cell cycle arrest and the down-regulation of AR activity/expression, possibly accounting for its primary growth inhibitory mechanism. Thus, it is conceivable that BFA may provide a more effective therapeutic modality for patients with hormone-dependent prostate cancer.
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Sun A, Tang J, Terranova PF, Zhang X, Thrasher JB, Li B. Adeno-associated virus-delivered short hairpin-structured RNA for androgen receptor gene silencing induces tumor eradication of prostate cancer xenografts in nude mice: a preclinical study. Int J Cancer 2010; 126:764-74. [PMID: 19642108 DOI: 10.1002/ijc.24778] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The androgen receptor (AR) is the most critical factor in prostate cancer progression. We previously demonstrated that silencing the AR using 2 unique small interfering RNAs (no. 8 and no. 31 AR siRNA) induces apoptotic cell death in AR-positive prostate cancer cells. To develop this AR siRNA technique into a therapy for prostate cancers, we generated an adeno-associated virus (AAV) vector to stably express a short hairpin-structured RNA (shRNA) against the AR gene in vivo. In addition to the no. 8 AR shRNA (ARHP8), we also screened a group of AR shRNAs with different sequences and identified a less effective AR shRNA (ARHP4) that was used as an shRNA control. An empty AAV vector (AAV-GFP) was used as a negative control. Intratumoral injection of AAV-ARHP8 viruses significantly suppressed tumor growth of xenografts derived from either androgen-responsive or castration-resistant prostate cancer cells. Most interestingly, systemic delivery of the AAV-ARHP8 but not AAV-ARHP4 or AAV-GFP viruses via tail vein injection eliminated xenografts within 10 days. Further analysis revealed that AAV-ARHP8 viruses dramatically reduced the expression of AR-regulated cellular survival genes and caused a dramatic apoptotic response. Taken together, our data strongly suggest that AAV-ARHP8 viruses induced a strong AR gene silencing in vivo and that systemic delivery of ARHP8 siRNA via an AAV vector or any other means might be considered as novel gene therapy for prostate cancers.
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Affiliation(s)
- Aijing Sun
- Department of Pathology, Shaoxing People's Hospital and the First Affiliated Hospital of Shaoxing University, Shaoxing, Zhejiang, China
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Vander Griend DJ, Antony L, Dalrymple SL, Xu Y, Christensen SB, Denmeade SR, Isaacs JT. Amino acid containing thapsigargin analogues deplete androgen receptor protein via synthesis inhibition and induce the death of prostate cancer cells. Mol Cancer Ther 2009; 8:1340-9. [PMID: 19417145 DOI: 10.1158/1535-7163.mct-08-1136] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
There are quantitative and/or qualitative mechanisms allowing androgen receptor (AR) growth signaling in androgen ablation refractory prostate cancer cells. Regardless of the mechanism, agents that deplete AR protein expression prevent such AR growth signaling. Thapsigargin (TG) is a highly cell-penetrant sequiterpene-lactone that once inside cells inhibits (IC(50), ∼ 10 nmol/L) critically important housekeeping SERCA 2b calcium pumps in the endoplasmic reticulum. Using a series of five genetically diverse androgen ablation refractory human prostate cancer lines (LNCaP, LAPC-4, VCaP, MDA-PCa-2b, and CWR22Rv1), TG inhibition of SERCA pumps consistently results in depletion of the endoplasmic reticulum Ca(+2) coupled with μmol/L elevation in the intracellular free Ca(+2) initiating a molecular cascade that: (a) inhibits Cap-dependent AR protein synthesis resulting in 90% depletion of AR protein by 24 hours of TG exposure, (b) arrests the cells in G(0), and (c) induces their apoptotic death. Unfortunately, due to its highly lipophilic nature, TG is not deliverable as a systemic agent without host toxicity. Therefore, TG analogues containing amino acids were developed, which retain ability to deplete AR protein and induce cell death and which can be covalently linked to peptide carriers producing water soluble prodrugs for systemic delivery. Specific amino acid sequences are used to restrict the liberation of cytotoxic amino acid containing TG analogues from the peptide prodrug by prostate-specific proteases, such as prostate-specific antigen and prostate-specific membrane antigen, or cancer-specific proteases, such as fibroblast activation protein, so that toxicity of these prodrugs is selectively targeted to metastatic sites of prostate cancer. Based on these results, these prodrugs are undergoing clinical development.
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Affiliation(s)
- Donald J Vander Griend
- The Sidney Kimmel Comprehensive Cancer Center, the Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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28
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Cohen MB, Rokhlin OW. Mechanisms of prostate cancer cell survival after inhibition of AR expression. J Cell Biochem 2009; 106:363-71. [PMID: 19115258 DOI: 10.1002/jcb.22022] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent reports have shown that the AR is the key determinant of the molecular changes required for driving prostate cancer cells from an androgen-dependent to an androgen-independent or androgen depletion-independent (ADI) state. Several recent publications suggest that down-regulation of AR expression should therefore be considered the principal strategy for the treatment of ADI prostate cancer. However, no valid data is available about how androgen-dependent prostate cancer cells respond to apoptosis-inducing drugs after knocking down AR expression and whether prostate cancer cells escape apoptosis after inhibition of AR expression. This review will focus on mechanisms of prostate cancer cell survival after inhibition of AR activity mediated either by androgen depletion or by targeting the expression of AR by siRNA. We have shown that knocking down AR expression by siRNA induced PI3K-independent activation of Akt, which was mediated by calcium/calmodulin-dependent kinase II (CaMKII). We also showed that the expression of CaMKII genes is under AR control: active AR in the presence of androgens inhibits CaMKII gene expression whereas inhibition of AR activity results in an elevated level of kinase activity and in enhanced expression of CaMKII genes. This in turn activates the anti-apoptotic PI3K/Akt pathways. CaMKII also express anti-apoptotic activity that is independent from the Akt pathway. This may therefore be an important mechanism by which prostate cancer cells escape apoptosis after androgen depletion or knocking down AR expression. In addition, we have found that there is another way to escape cell death after AR inhibition: DNA damaging agents cannot fully activate p53 in the absence of AR and as a result p53 down stream targets, for example, microRNA-34, cannot be activated and induce apoptosis. This implies that there may be a need for re-evaluation of the therapeutic approaches to human prostate cancer.
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Affiliation(s)
- Michael B Cohen
- Department of Pathology, The University of Iowa, Iowa City, Iowa 52242, USA.
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29
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Abstract
Despite the fact that almost all men will develop symptoms associated with benign prostatic hyperplasia within their lifetimes, no molecular markers for the disease or its likelihood to progress have been established. A marker of this type could be used to stratify patients into subpopulations as well as to identify individuals whose disease is most likely to progress. Several molecular biomarkers have high potential to fulfill these needs, although none is currently approved for the clinical setting. The future does look promising as research to find novel biologic biomarkers is progressing while existing markers are optimized and validated for clinical use.
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Affiliation(s)
- Grant W Cannon
- The Brady Urological Institute, Johns Hopkins Hospital, Marburg 121, 600 North Wolfe Street, Baltimore, MD 21287, USA
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30
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Tang YQ, Han BM, Yao XQ, Hong Y, Wang Y, Zhao FJ, Yu SQ, Sun XW, Xia SJ. Chimeric molecules facilitate the degradation of androgen receptors and repress the growth of LNCaP cells. Asian J Androl 2009; 11:119-26. [PMID: 19050678 PMCID: PMC3735208 DOI: 10.1038/aja.2008.26] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 10/13/2008] [Indexed: 11/09/2022] Open
Abstract
Post-translational degradation of protein plays an important role in cell life. We employed chimeric molecules (dihydrotestosterone-based proteolysis-targeting chimeric molecule [DHT-PROTAC]) to facilitate androgen receptor (AR) degradation via the ubiquitin-proteasome pathway (UPP) and to investigate the role of AR in cell proliferation and viability in androgen-sensitive prostate cancer cells. Western blot analysis and immunohistochemistry were applied to analyse AR levels in LNCaP cells after DHT-PROTAC treatment. Cell counting and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cell viability assay were used to evaluate cell proliferation and viability after AR elimination in both LNCaP and PC-3 cells. AR was tagged for elimination via the UPP by DHT-PROTAC, and this could be blocked by proteasome inhibitors. Degradation of AR depended on DHT-PROTAC concentration, and either DHT or an ALAPYIP-(arg)(8) peptide could compete with DHT-PROTAC. Inhibition of cell proliferation and decreased viability were observed in LNCaP cells, but not in PC-3 or 786-O cells after DHT-PROTAC treatment. These data indicate that AR elimination is facilitated via the UPP by DHT-PROTAC, and that the growth of LNCaP cells is repressed after AR degradation.
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Affiliation(s)
- Yue-Qing Tang
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
- Institute of Urology, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Bang-Min Han
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Xin-Quan Yao
- Department of Urology, Wujiang Third People's Hospital, Suzhou 215228, China
| | - Yan Hong
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
- Institute of Urology, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Yan Wang
- Department of Immunology, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Fu-Jun Zhao
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Sheng-Qiang Yu
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
- Institute of Urology, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Xiao-Wen Sun
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Shu-Jie Xia
- Department of Urology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
- Institute of Urology, Shanghai Jiao Tong University, Shanghai 200025, China
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31
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Yu SQ, Lai KP, Xia SJ, Chang HC, Chang C, Yeh S. The diverse and contrasting effects of using human prostate cancer cell lines to study androgen receptor roles in prostate cancer. Asian J Androl 2009; 11:39-48. [PMID: 19098932 PMCID: PMC3735204 DOI: 10.1038/aja.2008.44] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2008] [Accepted: 11/09/2008] [Indexed: 02/06/2023] Open
Abstract
The androgen receptor (AR) plays an important role in the development and progression of prostate cancer (PCa). Androgen deprivation therapy is initially effective in blocking tumor growth, but it eventually leads to the hormone-refractory state. The detailed mechanisms of the conversion from androgen dependence to androgen independence remain unclear. Several PCa cell lines were established to study the role of AR in PCa, but the results were often inconsistent or contrasting in different cell lines, or in the same cell line grown under different conditions. The cellular and molecular alteration of epithelial cells and their microenvironments are complicated, and it is difficult to use a single cell line to address this important issue and also to study the pathophysiological effects of AR. In this paper, we summarize the different effects of AR on multiple cell lines and show the disadvantages of using a single human PCa cell line to study AR effects on PCa. We also discuss the advantages of widely used epithelium-stroma co-culture systems, xenograft mouse models, and genetically engineered PCa mouse models. The combination of in vitro cell line studies and in vivo mouse models might lead to more credible results and better strategies for the study of AR roles in PCa.
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Affiliation(s)
- Sheng-Qiang Yu
- Department of Urology,The First People's Hospital of Shanghai Jiao Tong University, Shanghai 200080, China
- George Whipple Laboratory for Cancer Research, Departments of Pathology and Urology, The Cancer Center, University of Rochester, Rochester, NY 14642, USA
| | - Kuo-Pao Lai
- George Whipple Laboratory for Cancer Research, Departments of Pathology and Urology, The Cancer Center, University of Rochester, Rochester, NY 14642, USA
| | - Shu-Jie Xia
- Department of Urology,The First People's Hospital of Shanghai Jiao Tong University, Shanghai 200080, China
| | - Hong-Chiang Chang
- Department of Urology, National Taiwan University/Hospital, Taipei 100, Taiwan, China
| | - Chawnshang Chang
- George Whipple Laboratory for Cancer Research, Departments of Pathology and Urology, The Cancer Center, University of Rochester, Rochester, NY 14642, USA
| | - Shuyuan Yeh
- George Whipple Laboratory for Cancer Research, Departments of Pathology and Urology, The Cancer Center, University of Rochester, Rochester, NY 14642, USA
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Yang Q, Titus MA, Fung KM, Lin HK. 5alpha-androstane-3alpha,17beta-diol supports human prostate cancer cell survival and proliferation through androgen receptor-independent signaling pathways: implication of androgen-independent prostate cancer progression. J Cell Biochem 2008; 104:1612-24. [PMID: 18320593 DOI: 10.1002/jcb.21731] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Androgen and androgen receptor (AR) are involved in growth of normal prostate and development of prostatic diseases including prostate cancer. Androgen deprivation therapy is used for treating advanced prostate cancer. This therapeutic approach focuses on suppressing the accumulation of potent androgens, testosterone and 5alpha-dihydrotestosterone (5alpha-DHT), or inactivating the AR. Unfortunately, the majority of patients with prostate cancer eventually advance to androgen-independent states and no longer respond to the therapy. In addition to the potent androgens, 5alpha-androstane-3alpha,17beta-diol (3alpha-diol), reduced from 5alpha-DHT through 3alpha-hydroxysteroid dehydrogenases (3alpha-HSDs), activated signaling may represent a novel pathway responsible for the progression to androgen-independent prostate cancer. Androgen sensitive human prostate cancer LNCaP cells were used to compare 5alpha-DHT and 3alpha-diol activated androgenic effects. In contrast to 5alpha-DHT, 3alpha-diol regulated unique patterns of beta-catenin and Akt expression as well as Akt phosphorylation in parental and in AR-silenced LNCaP cells. More significantly, 3alpha-diol, but not 5alpha-DHT, supported AR-silenced LNCaP cells and AR negative prostate cancer PC-3 cell proliferation. 3alpha-diol-activated androgenic effects in prostate cells cannot be attributed to the accumulation of 5alpha-DHT, since 5alpha-DHT formation was not detected following 3alpha-diol administration. Potential accumulation of 3alpha-diol, as a result of elevated 3alpha-HSD expression in cancerous prostate, may continue to support prostate cancer growth in the presence of androgen deprivation. Future therapeutic strategies for treating advanced prostate cancer might need to target reductive 3alpha-HSD to block intraprostatic 3alpha-diol accumulation.
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Affiliation(s)
- Qing Yang
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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33
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Singh P, Hallur G, Anchoori RK, Bakare O, Kageyama Y, Khan SR, Isaacs JT. Rational design of novel antiandrogens for neutralizing androgen receptor function in hormone refractory prostate cancer. Prostate 2008; 68:1570-81. [PMID: 18668523 PMCID: PMC3087493 DOI: 10.1002/pros.20821] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The standard hormonal therapy with currently available antiandrogens and the leutinizing hormone releasing hormone (LHRH) analogs is not effective in the hormone-refractory stage of prostate cancer due to changes in androgen receptor (AR) signaling axis. In this refractory stage, AR continues to play a significant role in the growth of cancer cells even though the cancer cells are no longer dependent on the level of circulating androgens. METHODS A series of 11beta-Delta(9)-19 nortestosterone compounds were designed through structure-based rationale and tested for their binding affinity against AR and glucocorticoid receptor (GR) using fluorescence polarization assays, their agonistic ability to induce AR dependent transcription using PSA-driven report gene assays, and their growth inhibitory affects against a series of AR positive (LAPC4, LNCap, and CWR22R) and negative human prostate cancer cell lines (PC3) using MTT cell proliferation assays. RESULTS This study proposes the design of novel bifunctional antiandrogens based on the conjugation of 11beta and/or 7alpha-Delta(9)-19 nortestosterone class of steroidal compounds to the synthetic ligand for FK506-binding proteins. As a critical step towards the development of bifunctional antiandrogens, highly potent and AR-specific lead compounds were identified using in vitro data. The lead compounds identified in this study possessed low binding affinity for GR, indicating the absence of undesirable antiglucocorticoid activity. CONCLUSIONS The results of this study validate our drug discovery rationale based on the structural biology of AR and pave the pay for future development of bifunctional compounds in order to block AR function in hormone refractory stage of prostate cancer.
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Affiliation(s)
- Pratap Singh
- Chemical and Biomolecular Engineering, Whiting School of Engineering, Baltimore, Maryland
- Chemical Therapeutics Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Research Center, Johns Hopkins University, Maryland
- Correspondence to: Pratap Singh, Pharmacokinetics, Dynamics & Metabolism, Pfizer Global Research and Development, Pfizer Inc., Chesterfield, Missouri
| | - Gurulingappa Hallur
- Chemical Therapeutics Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Research Center, Johns Hopkins University, Maryland
| | - Ravi K. Anchoori
- Chemical Therapeutics Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Research Center, Johns Hopkins University, Maryland
| | - Oladapo Bakare
- Department of Chemistry, Howard University, Washington, District of Columbia
| | - Yukio Kageyama
- Department of Urology, Saitama Cancer Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Saeed R. Khan
- Chemical Therapeutics Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Research Center, Johns Hopkins University, Maryland
| | - John T. Isaacs
- Chemical and Biomolecular Engineering, Whiting School of Engineering, Baltimore, Maryland
- Chemical Therapeutics Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Research Center, Johns Hopkins University, Maryland
- Correspondence to: John T. Isaacs, Oncology & Urology, 1650 Orleans Street, CRB1 1M44, Baltimore, MD 21231-1000.
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A cross-talk between the androgen receptor and the epidermal growth factor receptor leads to p38MAPK-dependent activation of mTOR and cyclinD1 expression in prostate and lung cancer cells. Int J Biochem Cell Biol 2008; 41:603-14. [PMID: 18692155 DOI: 10.1016/j.biocel.2008.07.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2008] [Revised: 07/14/2008] [Accepted: 07/16/2008] [Indexed: 11/20/2022]
Abstract
In androgen sensitive LNCaP prostate cancer cells, the proliferation induced by the epidermal growth factor (EGF) involves a cross-talk between the EGF receptor (EGFR) and the androgen receptor (AR). In lung cancer the role of the EGF-EGFR transduction pathway has been documented, whereas androgen activity has received less attention. Here we demonstrate that in LNCaP and A549 non-small cell lung cancer (NSCLC), AR and EGFR are required for either 5alpha-dihydrotestosterone (DHT) or EGF-stimulated cell growth. Only EGF activated ERK signaling and up-regulated early gene expression, while DHT triggered the expression of classical AR-responsive genes with the exception of the EGF-induced PSA transcript in A549 cells. DHT and EGF up-regulated cyclinD1 (CD1) at both mRNA and protein levels in A549 cells, while in LNCaP cells each mitogen increased only CD1 protein expression. In both cell contexts, CD1 up-regulation was prevented by selective inhibitors as well as by knock-down of either AR or EGFR and also inhibiting p38MAPK and the mammalian target of rapamycin (mTOR) pathways. Interestingly, p38MAPK and mTOR repression prevented the activation of the mTOR target ribosomal p70S6 kinase induced by DHT and EGF, indicating that p38MAPK acts as an upstream mTOR regulator. In addition, the proliferative effects promoted by both DHT and EGF in LNCaP and A549 cancer cells were no longer observed blocking either p38MAPK or mTOR activity. Hence, our data suggest that p38MAPK-dependent activation of the mTOR/CD1 pathway may represent a mechanism through which AR and EGFR cross-talk contributes to prostate and lung cancer progression.
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35
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Wang S, Yang Q, Fung KM, Lin HK. AKR1C2 and AKR1C3 mediated prostaglandin D2 metabolism augments the PI3K/Akt proliferative signaling pathway in human prostate cancer cells. Mol Cell Endocrinol 2008; 289:60-6. [PMID: 18508192 DOI: 10.1016/j.mce.2008.04.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 04/01/2008] [Accepted: 04/04/2008] [Indexed: 11/23/2022]
Abstract
Members of the aldo-keto reductase (AKR) superfamily have been implicated in prostaglandin (PG) metabolism and prostate cancer. AKR1C3 possesses 11-ketoprostaglandin reductase activity and is capable of converting PGD2 to 9alpha, 11beta-PGF2alpha, whereas AKR1C2-mediated PG metabolism remains unclear. The accumulation of PGF2alpha may generate proliferative signals to promote prostate cell growth. Levels of AKR1C2 and AKR1C3 expression are elevated in localized and advanced prostate cancer. To study the significance of AKR1C2- and AKR1C3-mediated PGD2 conversion in human prostate cell proliferation, we stably transfected androgen insensitive human prostate cancer PC-3 cells with AKR1C2 or AKR1C3 cDNA. PC-3 cells overexpressing AKR1C2 and AKR1C3 had elevated cell proliferation in response to PGD2 stimulation as compared to mock transfectants. Overexpression of AKR1C2 or AKR1C3 did not alter levels of PGF receptor (FP) expression. Inclusion of an FP antagonist (AL8810) significantly suppressed PGD2-stimulated PC-3 cell proliferation in these stable transfectants. In addition, PGD2 significantly elevated levels of total Akt protein expression and Akt Ser473 phosphorylation in AKR1C2 and AKR1C3 stable transfectants; and inclusion of a phosphatidylinositol 3-kinase (PI3K) chemical inhibitor (LY294002) attenuated PGD2-stimulated cell proliferation in these transfectants. Our results suggested that both AKR1C2 and AKR1C3 mediate similar PGD2 conversion toward the accumulation of proliferative signals through FP and PI3K/Akt signaling pathways to promote prostate cell proliferation.
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Affiliation(s)
- Shaobin Wang
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States
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36
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Kaulfuss S, Grzmil M, Hemmerlein B, Thelen P, Schweyer S, Neesen J, Bubendorf L, Glass AG, Jarry H, Auber B, Burfeind P. Leupaxin, a novel coactivator of the androgen receptor, is expressed in prostate cancer and plays a role in adhesion and invasion of prostate carcinoma cells. Mol Endocrinol 2008; 22:1606-21. [PMID: 18451096 DOI: 10.1210/me.2006-0546] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In the present study, we demonstrate that leupaxin mRNA is overexpressed in prostate cancer (PCa) as compared with normal prostate tissue by using cDNA arrays and quantitative RT-PCR analyses. Moderate to strong expression of leupaxin protein was detected in approximately 22% of the PCa tissue sections analyzed, and leupaxin expression intensities were found to be significantly correlated with Gleason patterns/scores. In addition, different leupaxin expression levels were observed in PCa cell lines, and at the subcellular level, leupaxin was usually localized in focal adhesion sites. Furthermore, mutational analysis and transfection experiments of LNCaP cells using different green fluorescent protein-leupaxin constructs demonstrated that leupaxin contains functional nuclear export signals in its LD3 and LD4 motifs, thus shuttling between the cytoplasm and the nucleus. We could also demonstrate for the first time that leupaxin interacts with the androgen receptor in a ligand-dependent manner and serves as a transcriptional activator of this hormone receptor in PCa cells. Down-regulation of leupaxin expression using RNA interference in LNCaP cells resulted in a high rate of morphological changes, detachment, spontaneous apoptosis, and a reduction of prostate-specific antigen secretion. In contrast, knockdown of leupaxin expression in androgen-independent PC-3 and DU 145 cells induced a significant decrease of both the invasive capacity and motility. Our results therefore indicate that leupaxin could serve as a potential progression marker for a subset of PCa and may represent a novel coactivator of the androgen receptor. Leupaxin could function as a putative target for therapeutic interventions of a subset of advanced PCa.
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Affiliation(s)
- Silke Kaulfuss
- Institute of Human Genetics, University of Göttingen, Heinrich-Düker Weg 12, Göttingen, Germany
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Dozmorov MG, Yang Q, Matwalli A, Hurst RE, Culkin DJ, Kropp BP, Lin HK. 5alpha-androstane-3alpha,17beta-diol selectively activates the canonical PI3K/AKT pathway: a bioinformatics-based evidence for androgen-activated cytoplasmic signaling. Genomic Med 2008; 1:139-46. [PMID: 18923939 DOI: 10.1007/s11568-008-9018-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 02/14/2008] [Indexed: 11/28/2022] Open
Abstract
5alpha-Androstane-3alpha,17beta-diol (3alpha-diol) is reduced from the potent androgen, 5alpha-dihydrotestosterone (5alpha-DHT), by reductive 3alpha-hydroxysteroid dehydrogenases (3alpha-HSDs) in the prostate. 3alpha-diol is recognized as a weak androgen with low affinity toward the androgen receptor (AR), but can be oxidized back to 5alpha-DHT. However, 3alpha-diol may have potent effects by activating cytoplasmic signaling pathways, stimulating AR-independent prostate cell growth, and, more importantly, providing a key signal for androgen-independent prostate cancer progression. A cancer-specific, cDNA-based membrane array was used to determine 3alpha-diol-activated pathways in regulating prostate cancer cell survival and/or proliferation. Several canonical pathways appeared to be affected by 3alpha-diol-regulated responses in LNCaP cells; among them are apoptosis signaling, PI3K/AKT signaling, and death receptor signaling pathways. Biological analysis confirmed that 3alpha-diol stimulates AKT activation; and the AKT pathway can be activated independent of the classical AR signaling. These observations sustained our previous observations that 3alpha-diol continues to support prostate cell survival and proliferation regardless the status of the AR. We provided the first systems biology approach to demonstrate that 3alpha-diol-activated cytoplasmic signaling pathways are important components of androgen-activated biological functions in human prostate cells. Based on the observations that levels of reductive 3alpha-HSD expression are significantly elevated in localized and advanced prostate cancer, 3alpha-diol may, therefore, play a critical role for the transition from androgen-dependent to androgen-independent prostate cancer in the presence of androgen deprivation.
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Affiliation(s)
- Mikhail G Dozmorov
- Department of Urology, University of Oklahoma Health Sciences Center, 800 Research Parkway, Room 462, Oklahoma City, OK, 73104, USA
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Expression of androgen receptor is negatively regulated by p53. Neoplasia 2008; 9:1152-9. [PMID: 18084622 DOI: 10.1593/neo.07769] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 10/15/2007] [Accepted: 10/15/2007] [Indexed: 12/11/2022] Open
Abstract
Increased expression of androgen receptor (AR) in prostate cancer (PC) is associated with transition to androgen independence. Because the progression of PC to advanced stages is often associated with the loss of p53 function, we tested whether the p53 could regulate the expression of AR gene. Here we report that p53 negatively regulates the expression of AR in prostate epithelial cells (PrECs). We found that in LNCaP human prostate cancer cells that express the wild-type p53 and AR and in human normal PrECs, the activation of p53 by genotoxic stress or by inhibition of p53 nuclear export downregulated the expression of AR. Furthermore, forced expression of p53 in LNCaP cells decreased the expression of AR. Conversely, knockdown of p53 expression in LNCaP cells increased the AR expression. Consistent with the negative regulation of AR expression by p53, the p53-null HCT116 cells expressed higher levels of AR compared with the isogenic HCT116 cells that express the wildtype p53. Moreover, we noted that in etoposide treated LNCaP cells p53 bound to the promoter region of the AR gene, which contains a potential p53 DNA-binding consensus sequence, in chromatin immunoprecipitation assays. Together, our observations provide support for the idea that the loss of p53 function in prostate cancer cells contributes to increased expression of AR.
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Olson BM, McNeel DG. Antibody and T-cell responses specific for the androgen receptor in patients with prostate cancer. Prostate 2007; 67:1729-39. [PMID: 17879963 DOI: 10.1002/pros.20652] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND The androgen receptor (AR) is a steroid hormone receptor that is an essential regulator of prostate development, and the primary molecular target for the treatment of metastatic prostate cancer. In this report, we evaluated whether patients with prostate cancer have pre-existing immune responses specific for the AR as evidence that the AR also might be pursued as an immunological target antigen. METHODS The detection of auto-antibodies specific for the AR in patient sera was evaluated by ELISA and Western blotting. Peripheral blood mononuclear cells were analyzed for the presence of AR-specific T-cells, as measured by T-cell proliferation, interferon gamma (IFNgamma) and interleukin-10 secretion. RESULTS We found that a significantly higher frequency of prostate cancer patients have AR LBD-specific antibody responses than do healthy male volunteers [18/105 cancer patients (17.1%) vs. 0/41 healthy volunteers, P = 0.0049], and that these responses were present regardless of the patients' disease stage [8/46 organ-confined prostate cancer patients (17.4%), 3/22 metastatic androgen-dependent patients (13.6%), and 7/37 metastatic, androgen-independent patients (18.9%)]. These antibodies were pre-dominantly of the IgG isotype, and furthermore of the IgG(2) sub-isotype. In addition, we found that patients with antibody responses also had concurrent antigen-specific CD4+ and CD8+ T-cell proliferation and IFNgamma secretion when compared to patients without antibody responses. CONCLUSIONS These data demonstrate that some patients with prostate cancer have pre-existing humoral and cellular immune responses specific for the AR, suggesting that tolerance against the AR is not absolute and that the AR may be a potential immunotherapeutic target antigen.
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Affiliation(s)
- Brian M Olson
- Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Tararova ND, Narizhneva N, Krivokrisenko V, Gudkov AV, Gurova KV. Prostate cancer cells tolerate a narrow range of androgen receptor expression and activity. Prostate 2007; 67:1801-15. [PMID: 17935158 PMCID: PMC2914504 DOI: 10.1002/pros.20662] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The precise role of androgen receptor (AR) in the normal development of prostate and the progression of prostate cancer (CaP) remains controversial. While AR expression and activity is associated with growth arrest and differentiation of normal prostate cells, it is maintained in CaP cells that are characterized by continued proliferation. Our objective was to determine the importance of AR signaling for survival and growth of CaP cells, particularly those with a hormone-refractory phenotype. METHOD AR expression was modulated in androgen-sensitive (AS) and androgen-insensitive (AI) CaP cells using RNAi and cDNA transduction. Resulting changes in AR transcriptional activity and cell growth were quantified. RESULTS Interference with AR expression in both AS and AI CaP cells by shRNA transduction demonstrated a direct correlation between residual AR expression and cell viability. CaP cells lacking AR expression undergo apoptosis several days after AR down-regulation. This delayed response suggests that AR regulates apoptosis likely through an indirect mechanism. Overexpression of AR or hyper-stimulation of AR with high levels of androgen was also poorly tolerated by CaP cells. Cells with elevated AR had a growth disadvantage due to G1 cell cycle arrest and induction of p21 and GADD45 expression. CONCLUSIONS CaP cells expressing endogenous AR are sensitive to both increases and decreases in AR expression levels and activity. AR in CaP cells is delicately regulated to provide a balance between cell death and continued proliferation. Thus, both approaches, inhibition and over-stimulation of AR activity, may have therapeutic value for treatment of prostate cancer.
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MESH Headings
- Apoptosis/physiology
- Blotting, Western
- Cell Cycle/physiology
- Cell Growth Processes/physiology
- Cell Line, Tumor
- Dihydrotestosterone/pharmacology
- Humans
- Male
- Neoplasms, Hormone-Dependent/genetics
- Neoplasms, Hormone-Dependent/metabolism
- Neoplasms, Hormone-Dependent/pathology
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- RNA Interference
- RNA, Small Interfering/genetics
- Receptors, Androgen/biosynthesis
- Receptors, Androgen/deficiency
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Signal Transduction
- Transcription, Genetic
- Transfection
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Affiliation(s)
- Natalia D. Tararova
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | | | | | - Andrei V. Gudkov
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York
| | - Katerina V. Gurova
- Cleveland BioLabs, Inc., Buffalo, New York
- Correspondence to: Katerina V. Gurova, Anti-Cancer Drug Discovery, Cleveland BioLabs, 73 High Street, Buffalo, NY 14203.
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Serum/glucocorticoid-induced protein kinase-1 facilitates androgen receptor-dependent cell survival. Cell Death Differ 2007; 14:2085-94. [PMID: 17932503 DOI: 10.1038/sj.cdd.4402227] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Androgen receptor (AR) is a critical factor in the development and progression of prostate cancer. We and others recently demonstrated that eliminating AR expression leads to apoptotic cell death in AR-positive prostate cancer cells. To understand the mechanisms of AR-dependent survival, we performed a genome-wide search for AR-regulated survival genes. We found that serum/glucocorticoid-induced protein kinase-1 (SGK-1) mRNA levels were significantly upregulated after androgen stimulation, which was confirmed to be AR dependent. Promoter analysis revealed that the AR interacted with the proximal and distal regions of the sgk1 promoter, leading to sgk-1 promoter activation after androgen stimulation. Functional assays demonstrated that SGK-1 was indispensable for the protective effect of androgens on cell death induced by serum starvation. SGK-1 overexpression not only rescued cells from AR small-interfering RNA (siRNA)-induced apoptosis, but also enhanced AR transactivation, even in the absence of androgen. Additionally, SGK-1 siRNA reduced AR transactivation, indicating a positive feedback effect of SGK-1 expression on AR-mediated gene expression and cellular survival. Taken together, our data suggest that SGK-1 is an androgen-regulated gene that plays a pivotal role in AR-dependent survival and gene expression.
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Inoue T, Kobayashi T, Terada N, Shimizu Y, Kamoto T, Ogawa O, Nakamura E. Roles of androgen-dependent and -independent activation of signal transduction pathways for cell proliferation of prostate cancer cells. Expert Rev Endocrinol Metab 2007; 2:689-704. [PMID: 30736131 DOI: 10.1586/17446651.2.5.689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prostate cancer is one of the most frequently diagnosed cancers in the western world and this malignant neoplasm is the second-leading cause of cancer death among men in the USA. In the early 1940s, Huggins and Hodges demonstrated that growth and survival of prostate cancer depends on androgens. The mainstay of treatment for advanced prostate cancer is currently androgen ablation. Over the past few decades, several compounds, such as luteinizing hormone-releasing hormone analogues and anti-androgens, were developed and widely used in clinics. Then, the new treatment strategy, maximum androgen blockade (MAB) was introduced. In fact, MAB improved the prognosis of patients with advanced prostate cancer to some extent; however, most of those patients finally relapse after a period of initial response to this therapy, developing androgen-independent prostate cancer (AIPC). Once patients develop AIPC, effective therapeutic modalities are extremely limited and, therefore, the prognosis of this disease is very poor. It is strongly desirable to explore novel therapeutic concepts for AIPC, based on detailed molecular mechanisms for progression to androgen independency. As for the molecular mechanisms involved in the emergence of AIPC, mutations in the androgen receptor have been examined most extensively. These days, evidence is accumulating that demonstrates activation of signal transduction pathways, such as Src, PI3K and mTOR/S6K, are involved in the acquisition of the androgen-independent cell proliferation of prostate cancer cells. In addition, animal models using transgenic and gene-knockout techniques have confirmed these results. The development of therapies targeting against the signal transduction pathways is critical for the improvement of the prognosis of patients with AIPC. In this article, we review recent understandings on molecular mechanisms of androgen-dependent proliferation of prostate cancer cells, whose aberrant activation is proposed as a critical event for progression to AIPC.
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Affiliation(s)
- Takahiro Inoue
- a Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Takashi Kobayashi
- b Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Naoki Terada
- c Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Yosuke Shimizu
- d Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Toshiyuki Kamoto
- e Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Osamu Ogawa
- f Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Eijiro Nakamura
- g Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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Zong H, Chi Y, Wang Y, Yang Y, Zhang L, Chen H, Jiang J, Li Z, Hong Y, Wang H, Yun X, Gu J. Cyclin D3/CDK11p58 complex is involved in the repression of androgen receptor. Mol Cell Biol 2007; 27:7125-42. [PMID: 17698582 PMCID: PMC2168904 DOI: 10.1128/mcb.01753-06] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Androgen receptor (AR) is essential for the maintenance of the male reproductive systems and is critical for the carcinogenesis of human prostate cancers (PCas). D-type cyclins are closely related to the repression of AR function. It has been well documented that cyclin D1 inhibits AR function through multiple mechanisms, but the mechanism of how cyclin D3 exerts its repressive role in the AR signaling pathway remains to be identified. In the present investigation, we demonstrate that cyclin D3 and the 58-kDa isoform of cyclin-dependent kinase 11 (CDK11p58) repressed AR transcriptional activity as measured by reporter assays of transformed cells and prostate-specific antigen expression in PCa cells. AR, cyclin D3, and CDK11p58 formed a ternary complex in cells and were colocalized in the luminal epithelial layer of the prostate. AR activity is controlled by phosphorylation at specific sites. We found that AR was phosphorylated at Ser-308 by cyclin D3/CDK11p58 in vitro and in vivo, leading to the repressed activity of AR transcriptional activation unit 1 (TAU1). Furthermore, androgen-dependent proliferation of PCa cells was inhibited by cyclin D3/CDK11p58 through AR repression. These data suggest that cyclin D3/CDK11p58 signaling is involved in the negative regulation of AR function.
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Affiliation(s)
- Hongliang Zong
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, Gene Research Center, Shanghai Medical College, Shanghai 200032, People's Republic of China
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Ivanov NI, Cowell SP, Brown P, Rennie PS, Guns ES, Cox ME. Lycopene differentially induces quiescence and apoptosis in androgen-responsive and -independent prostate cancer cell lines. Clin Nutr 2007; 26:252-63. [PMID: 17337101 DOI: 10.1016/j.clnu.2007.01.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 11/15/2006] [Accepted: 01/07/2007] [Indexed: 11/29/2022]
Abstract
BACKGROUND & AIMS Lycopene has been credited with a number of health benefits including a decrease in prostate cancer risk. Our study investigates the molecular mechanism underlying anti-cancer activity of lycopene-based products in androgen-responsive (LNCaP) and androgen-independent (PC3) cells. METHODS The effect of lycopene-based agents on prostate cancer growth and survival were examined using proliferation assays, bromodeoxyuridine incorporation and flow cytometric analysis of cellular DNA content. Biochemical effects of lycopene treatment were investigated by immunoblotting for changes in the absolute levels and phosphorylation states of cell cycle regulatory and signalling proteins. RESULTS LNCaP and PC3 cells treated with the lycopene-based agents undergo mitotic arrest, accumulating in G0/G1 phase. Immunoblot screening indicated that lycopene's antiproliferative effects are likely achieved through a block in G1/S transition mediated by decreased levels of cyclins D1 and E and cyclin dependent kinase 4 and suppressed Retinoblastoma phosphorylation. These responses correlated with decreased insulin-like growth factor-I receptor expression and activation, increased insulin-like growth factor binding protein 2 expression and decreased AKT activation. Exposure to lycopene at doses as low as 10 nM for 48 h induced a profound apoptotic response in LNCaP cells. In contrast PC3 cells were resistant to apoptosis at doses up to 1 microM. CONCLUSIONS Lycopene exposure can suppress phosphatidylinositol 3-kinase-dependent proliferative and survival signalling in androgen-responsive LNCaP and androgen-independent PC3 cells suggesting that the molecular mechanisms for the cytostatic and cytotoxic actions of lycopene involve induction of G0/G1 cell cycle arrest. This study supports further examination of lycopene as a potential agent for both the prevention and treatment of prostate cancer.
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Affiliation(s)
- Nikita I Ivanov
- Prostate Research Centre at Vancouver General Hospital, University of British Columbia, 2660 Oak Street, Vancouver, BC, Canada V6T 1Z4
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45
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He ML, Chen WW, Zhang PJ, Jiang AL, Fan W, Yuan HQ, Liu WW, Zhang JY. Gum mastic increases maspin expression in prostate cancer cells. Acta Pharmacol Sin 2007; 28:567-72. [PMID: 17376297 DOI: 10.1111/j.1745-7254.2007.00535.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
AIM To study whether gum mastic, a natural resin, can regulate maspin expression in prostate cancer cells, and further investigate the mechanisms involved in this regulatory system. METHODS RT-PCR and Western blotting were used to detect maspin expression at the transcriptional and translational levels. Reporter gene assay was used to investigate the effect of gum mastic on the maspin promoter. The binding activity of negative androgen-responsive element (ARE) and positive Sp1 element in the maspin promoter were studied by electrophoretic mobility shift assay. RESULTS Gum mastic induced maspin mRNA and protein expression, and the maspin promoter activity was enhanced with gum mastic treatment. Finally, gum mastic inhibited the ARE binding activity and increased the Sp1 binding activity in the maspin promoter. CONCLUSION Gum mastic enhances maspin promoter activity by suppressing ARE binding activity and enhancing Sp1 binding activity, and the increased activity in the maspin promoter finally leads to the up-regulation of both its mRNA and protein levels.
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Affiliation(s)
- Mei-lan He
- Department of Biochemistry, Medical School, Shandong University, Ji-nan 250012, China
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46
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Zaidman BZ, Wasser SP, Nevo E, Mahajna J. Coprinus comatus and Ganoderma lucidum interfere with androgen receptor function in LNCaP prostate cancer cells. Mol Biol Rep 2007; 35:107-17. [PMID: 17431821 DOI: 10.1007/s11033-007-9059-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Accepted: 01/17/2007] [Indexed: 12/31/2022]
Abstract
In this study, we screened a total of 201 diethyl ether, ethanol, and ethyl acetate fungal Basidiomycetes extracts for anti-androgenic activity. Based on our screened results in combination with the selective inhibition of prostate cancer LNCaP cells, we selected Coprinus comatus and Ganoderma lucidum for further evaluation. We demonstrated that ethanol and ethyl acetate extracts from C. comatus and G. lucidum, respectively, selectively inhibit dihydrotestosterone-induced LNCaP cell viability, suppress levels of secreted prostate-specific antigen in a dose-dependent manner, and cause a G1 phase arrest in LNCaP, but not in DU 145 and PC-3 cells. For the first time, to the best of our knowledge, we demonstrated that C. comatus and G. lucidum decreased androgen and glucocorticoide receptors transcriptional activity in breast cancer MDA-kb2 cells in a dose-dependent manner, and suppressed androgen receptor (AR) protein level in LNCaP and MDA-kb2 cells. Our findings suggest that AR and non-AR mediated mechanisms underlie the effects of C. comatus and G. lucidum.
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Affiliation(s)
- Ben-Zion Zaidman
- Institute of Evolution, University of Haifa, Mount Carmel, Haifa, 31905, Israel
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Cannon GW, Mullins C, Lucia MS, Hayward SW, Lin V, Liu BCS, Slawin K, Rubin MA, Getzenberg RH. A preliminary study of JM-27: a serum marker that can specifically identify men with symptomatic benign prostatic hyperplasia. J Urol 2007; 177:610-4; discussion 614. [PMID: 17222644 DOI: 10.1016/j.juro.2006.09.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Indexed: 11/21/2022]
Abstract
PURPOSE Benign prostatic hyperplasia is a common disease in men that until recently was considered a single disease with varying symptoms. Our recent analysis has revealed that a molecular marker, JM-27, is able to distinguish at the tissue level between highly symptomatic individuals and those with histological disease. The goal of these studies was to determine if a serum based assay to detect JM-27 could distinguish men with different forms of benign prostatic hyperplasia. MATERIALS AND METHODS A serum based enzyme-linked immunosorbent assay was developed using a novel anti-JM-27 monoclonal antibody. The assay was sensitive, detecting JM-27 at the low ng/ml level within the serum. A quantitative measurement of serum JM-27 levels was performed in 68 patients. The patients consisted of 3 groups of 29 patients with asymptomatic benign prostatic hyperplasia (American Urological Association symptom score of 15 or less), 39 with symptomatic benign prostatic hyperplasia (American Urological Association symptom score 16 to 32) and 17 with confirmed prostate cancer. The assay cutoff was determined after a pilot run of samples and applied prospectively. RESULTS Using the determined cutoff, serum levels of JM-27 can distinguish between symptomatic and asymptomatic patient sets. The sensitivity and specificity of the assay are 90% and 77%, respectively. The presence of prostate cancer in these men does not appear to alter the marker levels. CONCLUSIONS The present study is believed to represent the first characterization of a serum based marker for severe benign prostatic hyperplasia.
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Affiliation(s)
- Grant W Cannon
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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48
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Wang LG, Ferrari AC. Mithramycin targets sp1 and the androgen receptor transcription level-potential therapeutic role in advanced prostate cancer. TRANSLATIONAL ONCOGENOMICS 2006; 1:19-31. [PMID: 23662037 PMCID: PMC3642134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
UNLABELLED Multiple lines of evidence implicate over-expression and activation of the androgen receptor (AR) in the progression of prostate cancer (PC) to androgen-independence (AI) and resistance to therapy. The mechanisms leading to AR over-expression are not fully understood but binding of Sp1 to specific Sp1-binding sites in the AR promoter and 5'-untranslated region (5'-UTR) was shown to up-regulate AR transcription. In this work, we further characterized the role of Sp1 in the control of AR transcription and explored its potential as a therapeutic target in androgen-dependent (AD) and independent (AI) LNCaP cells. We identified a pair of new Sp1-binding site in the 5'-UTR of AR which we named ARSp1-3. ARSp1-3 binds Sp1 with higher affinity than other known Sp1-binding sites in the promoter/5'-UTR and in transfection experiments, the ARSp1-3 reporter showed higher transcriptional activity in AI than in AD cells. Treatment of these cells with nanomolar concentrations of Mithramycin inhibited binding of Sp1 to its binding sites in the promoter/5'-UTR of the AR gene but more specifically the binding of ARSp1-3 while other regulatory elements of the AR promoter were not affected. Inhibition of Sp1 binding by Mithramycin decreased the AR transcription and transactivation of PSA reporter constructs. At the lowest concentrations, Mithramycin decreased endogenous AR protein and proliferation of AD and AI LNCaP cells. The combinations of Mithramycin with either paclitaxel or bicalutamide were highly synergistic. CONCLUSION Sp1 binding induces AR transcription in LNCaP cells. The higher affinity of ARSp1-3 for Sp1 may support higher AR mRNA levels in AI than AD LNCaP cells. Mithramycin is a potent and specific inhibitor of Sp1 and AR transcription with potential, at very low concentrations, to enhance the efficacy of hormones or taxane based therapy in patients with recurrent or androgen-independent progression that sustain AR expression.
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Affiliation(s)
- Long G. Wang
- Correspondence: Long G. Wang, NYU Cancer Institute, Department of Medicine, New York University School of Medicine, VAMC 18th floor, Room 18003W, Tel: (212) 263-4274; Fax: (212) 2636091;
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Litvinov IV, Vander Griend DJ, Antony L, Dalrymple S, De Marzo AM, Drake CG, Isaacs JT. Androgen receptor as a licensing factor for DNA replication in androgen-sensitive prostate cancer cells. Proc Natl Acad Sci U S A 2006; 103:15085-90. [PMID: 17015840 PMCID: PMC1622781 DOI: 10.1073/pnas.0603057103] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Androgen receptor (AR) protein expression and function are critical for survival and proliferation of androgen-sensitive (AS) prostate cancer cells. Besides its ability to function as a transcription factor, experimental observations suggest that AR becomes a licensing factor for DNA replication in AS prostate cancer cells and thus must be degraded during each cell cycle in these cells to allow reinitiation of DNA replication in the next cell cycle. This possibility was tested by using the AS human prostate cancer cell lines, LNCaP, CWR22Rv1, and LAPC-4. These studies demonstrated that AR levels fluctuate both within and between various phases of the cell cycle in each of these AS lines. Consistent with its licensing ability, AR is degraded during mitosis via a proteasome-dependent pathway in these AS prostate cancer cells. In contrast, proteasome-dependent degradation of AR during mitosis is not observed in AR-expressing but androgen-insensitive human prostate stromal cells, in which AR does not function as a licensing factor for DNA replication. To evaluate mitotic degradation of AR in vivo, the same series of human AS prostate cancers growing as xenografts in nude mice and malignant tissues obtained directly from prostate cancer patients were evaluated by dual Ki-67 and AR immunohistochemistry for AR expression in mitosis. These results document that AR is also down-regulated during mitosis in vivo. Thus, AS prostate cancer cells do not express AR protein during mitosis, either in vitro or in vivo, consistent with AR functioning as a licensing factor for DNA replication in AS prostate cancer cells.
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Affiliation(s)
- Ivan V. Litvinov
- *Chemical Therapeutics Program
- Cellular and Molecular Medicine Graduate Program
| | - Donald J. Vander Griend
- *Chemical Therapeutics Program
- Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231
| | | | | | - Angelo M. De Marzo
- Department of Pathology, and the
- Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231
| | - Charles G. Drake
- Division of Immunology and Hematopoiesis, The Sidney Kimmel Comprehensive Cancer Center
- Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231
| | - John T. Isaacs
- *Chemical Therapeutics Program
- Cellular and Molecular Medicine Graduate Program
- Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231
- To whom correspondence should be addressed at:
The Sidney Kimmel Comprehensive Cancer Center, Room 1M43, 1650 Orleans Street, Baltimore, MD 21231. E-mail:
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50
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Litvinov IV, Antony L, Dalrymple SL, Becker R, Cheng L, Isaacs JT. PC3, but not DU145, human prostate cancer cells retain the coregulators required for tumor suppressor ability of androgen receptor. Prostate 2006; 66:1329-38. [PMID: 16835890 DOI: 10.1002/pros.20483] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Androgen receptor (AR) functions in normal prostate epithelium as a tumor suppressor to inhibit continuous proliferation of these cells. Such tumor suppressor function of AR is lost in androgen depletion independent (ADI) prostate cancers. In type-I ADI cancers AR is not expressed, while in type-II ADI cancers AR is recaptured as an oncogene. The PC3 and DU145 human prostate cancer cell lines are representative of the earlier type-I ADI prostate cancers. While these cells do not express AR, it is unclear whether they retained the coactivators necessary for AR-dependent tumor suppression. To answer this question the response to AR protein expression by PC3 and DU145 cells was evaluated. METHODS To do this, a lentiviral AR (Lenti-AR) expression system was engineered to encode an AR transcript which includes appropriate 5' and 3' untranslated regions (UTRs) containing all previously identified post-transcriptional regulatory sequences. AR expression and transcriptional activity were evaluated in Lenti-AR transduced cells by Western blot and luciferase assay, respectively. Cell growth in culture and in mouse xenografts was evaluated in correlation to expression changes in p21, p27, and p45(SKP2) proteins. RESULTS Lenti-AR transduced PC3 and DU145 lines expressed transcriptionally functional AR protein at appropriate physiological levels. Expression and engagement of AR protein in PC3-Lenti-AR cells resulted in transactivation of p21 and subsequent growth inhibition of these cells in culture and in mouse xenografts. Such inhibition was due to induced G1 arrest of these cells as documented by expression changes in p27 and p45(SKP2) proteins. Such growth inhibition was not observed in DU145-Lenti-AR cells. CONCLUSIONS These results document that PC3, but not DU145 cells retain the coregulators needed for AR tumor suppressor ability.
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MESH Headings
- Animals
- Cell Line, Tumor
- Cyclin-Dependent Kinase Inhibitor p21/genetics
- Cyclin-Dependent Kinase Inhibitor p21/metabolism
- G1 Phase/physiology
- Gene Expression Regulation, Neoplastic/physiology
- Gene Expression Regulation, Viral/physiology
- Genes, Tumor Suppressor/physiology
- Humans
- Lentivirus/genetics
- Male
- Mice
- Proliferating Cell Nuclear Antigen/genetics
- Proliferating Cell Nuclear Antigen/metabolism
- Promoter Regions, Genetic/genetics
- Promoter Regions, Genetic/physiology
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/physiopathology
- Prostatic Neoplasms/virology
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Receptors, Androgen/physiology
- S-Phase Kinase-Associated Proteins/genetics
- S-Phase Kinase-Associated Proteins/metabolism
- Transduction, Genetic
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
- Tumor Suppressor Proteins/physiology
- Xenograft Model Antitumor Assays/methods
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Affiliation(s)
- Ivan V Litvinov
- Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland 21231, USA
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