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Tilley WD. Novel twists in hormone-mediated carcinogenesis. Endocr Relat Cancer 2016; 23:E9-E12. [PMID: 27836990 DOI: 10.1530/erc-16-0466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Wayne D Tilley
- Dame Roma Mitchell Cancer Research LaboratoriesSchool of Medicine, Faculty of Health Sciences, The University of Adelaide, Adelaide, Australia
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Rahaman MH, Kumarasiri M, Mekonnen LB, Yu M, Diab S, Albrecht H, Milne RW, Wang S. Targeting CDK9: a promising therapeutic opportunity in prostate cancer. Endocr Relat Cancer 2016; 23:T211-T226. [PMID: 27582311 DOI: 10.1530/erc-16-0299] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 08/31/2016] [Indexed: 12/18/2022]
Abstract
Cyclin-dependent kinase 9 (CDK9) is a key transcriptional regulator and a lucrative target for cancer treatment. Targeting CDK9 can effectively confine the hyperactivity of androgen receptor and the constitutive expression of anti-apoptotic proteins; both being main causes of prostate cancer (PCa) development and progression. In castrate-resistant PCa, traditional therapies that only target androgen receptor (AR) have become obsolete due to reprograming in AR activity to make the cells independent of androgen. CDK9 inhibitors may provide a new and better therapeutic opportunity over traditional treatment options by targeting both androgen receptor activity and anti-apoptotic proteins, improving the chances of positive outcomes, especially in patients with the advanced disease. This review focuses on biological functions of CDK9, its involvement with AR and the potential for therapeutic opportunities in PCa treatment.
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Affiliation(s)
| | | | - Laychiluh B Mekonnen
- Centre for Drug Discovery and DevelopmentSansom Institute for Health Research and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Mingfeng Yu
- Centre for Drug Discovery and DevelopmentSansom Institute for Health Research and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Sarah Diab
- Centre for Drug Discovery and DevelopmentSansom Institute for Health Research and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Hugo Albrecht
- Centre for Drug Discovery and DevelopmentSansom Institute for Health Research and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Robert W Milne
- Centre for Drug Discovery and DevelopmentSansom Institute for Health Research and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Shudong Wang
- Centre for Drug Discovery and DevelopmentSansom Institute for Health Research and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
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Hsiao YH, Huang YT, Hung CY, Kuo TC, Luo FJ, Yuan TC. PYK2 via S6K1 regulates the function of androgen receptors and the growth of prostate cancer cells. Endocr Relat Cancer 2016; 23:651-63. [PMID: 27492635 DOI: 10.1530/erc-16-0122] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 12/30/2022]
Abstract
Androgen receptor (AR) is a steroid hormone receptor that functions as a transcription factor for regulating cell growth and survival. Aberrant AR function becomes a risk factor for promoting the progression of prostate cancer (PCa). In this study, we examined the roles of proline-rich tyrosine kinase 2 (PYK2) and ribosomal S6 kinase 1 (S6K1) in regulating AR expression and activity and growth properties in PCa cells. Compared with normal prostate tissues, PCa tumors exhibited high levels of PYK2 and S6K1 expression. Furthermore, the expression levels of PYK2 and S6K1 were significantly correlated with nuclear AR expression in PCa tissues. We further found the association between PYK2, S6K1, and AR in their protein expression and phosphorylation levels among normal prostate PZ-HPV-7 cells and prostate cancer LNCaP and 22Rv1 cells. Overexpression of the wild-type PYK2 in PZ-HPV-7 and LNCaP cells promoted AR and S6K1 expression and phosphorylation as well as enhanced cell growth. In contrast, expression of the mutated PYK2 or knockdown of PYK2 expression in LNCaP or 22Rv1 cells caused reduced expression or phosphorylation of AR and S6K1 as well as retarded cell growth. Under an androgen-deprived condition, PYK2-promoted AR expression and phosphorylation and PSA production in LNCaP cells can be abolished by knocking down S6K1 expression. In summary, our data suggested that PYK2 via S6K1 activation modulated AR function and growth properties in PCa cells. Thus, PYK2 and S6K1 may potentially serve as therapeutic targets for PCa treatment.
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Affiliation(s)
- Yu-Hsuan Hsiao
- Department of Life ScienceNational Dong Hwa University, Hualien, Taiwan, Republic of China
| | - Yu-Ting Huang
- Department of Life ScienceNational Dong Hwa University, Hualien, Taiwan, Republic of China
| | - Chia-Yu Hung
- Department of Life ScienceNational Dong Hwa University, Hualien, Taiwan, Republic of China
| | - Tzu-Chien Kuo
- Department of Life ScienceNational Dong Hwa University, Hualien, Taiwan, Republic of China
| | - Fuh-Jinn Luo
- Department of PathologyMennonite Hospital, Hualien, Taiwan, Republic of China
| | - Ta-Chun Yuan
- Department of Life ScienceNational Dong Hwa University, Hualien, Taiwan, Republic of China
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Karantanos T, Karanika S, Wang J, Yang G, Dobashi M, Park S, Ren C, Li L, Basourakos SP, Hoang A, Efstathiou E, Wang X, Troncoso P, Titus M, Broom B, Kim J, Corn PG, Logothetis CJ, Thompson TC. Caveolin-1 regulates hormone resistance through lipid synthesis, creating novel therapeutic opportunities for castration-resistant prostate cancer. Oncotarget 2016; 7:46321-46334. [PMID: 27331874 PMCID: PMC5216801 DOI: 10.18632/oncotarget.10113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/03/2016] [Indexed: 12/11/2022] Open
Abstract
Caveolin-1 (Cav-1) is overexpressed in aggressive and metastatic prostate cancer (PCa) and induces PCa cell proliferation. Androgens mediate lipid synthesis through acetyl-CoA carboxylase-1 (ACC1) and fatty acid synthase (FASN). We investigated the Cav-1-mediated lipid synthesis in the development of castration resistance, and identified novel therapeutic opportunities. Using the PBCre+;Ptenloxp/loxp;PBCav-1+ mouse model we found that Cav-1 induction increased cancer incidence and growth, and ACC1-FASN expression in intact and castrated mice. We demonstrated that Cav-1 regulated ACC1 and FASN expression in an AR-independent way and increased palmitate synthesis using western blot analysis, qRT-PCR and mass spectrometry in vitro. By using FASN siRNA and C-75, we found that FASN inhibition was more effective in Cav-1-overexpressing cells. This inhibition was abrogated by ACC1si RNA, revealing the role of malonyl-CoA, an ACC1 product, as a mediator of cytotoxicity. Cav-1 was associated with ACC1 in human tumors and ACC1, FASN, and Cav-1 expression were increased in metastatic PCa compared to primary tumors and normal prostate epithelium. Palmitoleate and oleate levels were higher in BMA from patients with metastatic PCa who responded poorly to abiraterone acetate. Our findings suggest that Cav-1 promotes hormone resistance through the upregulation of ACC1-FASN and lipid synthesis under androgen deprivation, suggesting that FASN inhibition could be used to treat PCa that demonstrates Cav-1 overexpression.
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Affiliation(s)
- Theodoros Karantanos
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
- Current address: General Internal Medicine Section, Boston Medical Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Styliani Karanika
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
- Current address: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI 02903, USA
| | - Jianxiang Wang
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Guang Yang
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Masato Dobashi
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Sanghee Park
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Chengzhen Ren
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Likun Li
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Spyridon P. Basourakos
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Anh Hoang
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Eleni Efstathiou
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Xuemei Wang
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Patricia Troncoso
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Mark Titus
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Bradley Broom
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Jeri Kim
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Paul G. Corn
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Christopher J. Logothetis
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
| | - Timothy C. Thompson
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
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55
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Misawa A, Takayama KI, Urano T, Inoue S. Androgen-induced Long Noncoding RNA (lncRNA) SOCS2-AS1 Promotes Cell Growth and Inhibits Apoptosis in Prostate Cancer Cells. J Biol Chem 2016; 291:17861-80. [PMID: 27342777 DOI: 10.1074/jbc.m116.718536] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Indexed: 11/06/2022] Open
Abstract
Long noncoding RNAs (lncRNA) have been associated with the development of cancer. However, the interplay between lncRNAs and androgen receptor (AR) signaling in prostate cancer is still unclear. Here, we identified lncRNAs induced by androgen in AR-positive prostate cancer cells, where induction was abolished by AR knockdown as well as an anti-androgen, bicalutamide. By combining these data, we identified an androgen-regulated lncRNA, suppressor of cytokine signaling 2-antisense transcript 1 (SOCS2-AS1), the expression of which was higher in castration-resistant prostate cancer model cells, i.e long-term androgen-deprived (LTAD) cells, than in parental androgen-dependent LNCaP cells. SOCS2-AS1 promoted castration-resistant and androgen-dependent cell growth. We found that SOCS2-AS1 knockdown up-regulated genes related to the apoptosis pathway, including tumor necrosis factor superfamily 10 (TNFSF10), and sensitized prostate cancer cells to docetaxel treatment. Moreover, we also demonstrated that SOCS2-AS1 promotes androgen signaling by modulating the epigenetic control for AR target genes including TNFSF10 These findings suggest that SOCS2-AS1 plays an important role in the development of castration-resistant prostate cancer by repressing apoptosis.
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Affiliation(s)
- Aya Misawa
- From the Department of Anti-aging Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Ken-Ichi Takayama
- From the Department of Anti-aging Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan, the Department of Functional Biogerontology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan, and
| | - Tomohiko Urano
- From the Department of Anti-aging Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Satoshi Inoue
- From the Department of Anti-aging Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan, the Department of Functional Biogerontology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan, and the Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Hidaka, Saitama 350-1241, Japan
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56
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Wu M, Kim SH, Datta I, Levin A, Dyson G, Li J, Kaypee S, Swamy MM, Gupta N, Kwon HJ, Menon M, Kundu TK, Reddy GPV. Hydrazinobenzoylcurcumin inhibits androgen receptor activity and growth of castration-resistant prostate cancer in mice. Oncotarget 2016; 6:6136-50. [PMID: 25704883 PMCID: PMC4467427 DOI: 10.18632/oncotarget.3346] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/20/2015] [Indexed: 01/09/2023] Open
Abstract
There is a critical need for therapeutic agents that can target the amino-terminal domain (NTD) of androgen receptor (AR) for the treatment of castration-resistant prostate cancer (CRPC). Calmodulin (CaM) binds to the AR NTD and regulates AR activity. We discovered that Hydrazinobenzoylcurcumin (HBC), which binds exclusively to CaM, inhibited AR activity. HBC abrogated AR interaction with CaM, suppressed phosphorylation of AR Serine81, and blocked the binding of AR to androgen-response elements. RNA-Seq analysis identified 57 androgen-regulated genes whose expression was significantly (p ≤ 0.002) altered in HBC treated cells as compared to controls. Oncomine analysis revealed that genes repressed by HBC are those that are usually overexpressed in prostate cancer (PCa) and genes stimulated by HBC are those that are often down-regulated in PCa, suggesting a reversing effect of HBC on androgen-regulated gene expression associated with PCa. Ingenuity Pathway Analysis revealed a role of HBC affected genes in cellular functions associated with proliferation and survival. HBC was readily absorbed into the systemic circulation and inhibited the growth of xenografted CRPC tumors in nude mice. These observations demonstrate that HBC inhibits AR activity by targeting the AR NTD and suggest potential usefulness of HBC for effective treatment of CRPC.
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Affiliation(s)
- Min Wu
- Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI, USA
| | - Sahn-Ho Kim
- Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI, USA
| | - Indrani Datta
- Bioinformatics Core, Public Health Sciences, Henry Ford Hospital, Detroit, MI, USA
| | - Albert Levin
- Bioinformatics Core, Public Health Sciences, Henry Ford Hospital, Detroit, MI, USA
| | - Gregory Dyson
- Biostatistics Core, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Jing Li
- Pharmacology Core, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Stephanie Kaypee
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore, Karnataka, India
| | - M Mahadeva Swamy
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore, Karnataka, India
| | - Nilesh Gupta
- Department of Pathology, Henry Ford Hospital, Detroit, MI, USA
| | - Ho Jeong Kwon
- Department of Biotechnology, Translational Research Center for Protein Function Control, Yonsei University, Seoul, Republic of Korea
| | - Mani Menon
- Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI, USA
| | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore, Karnataka, India
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Zheng Y, Murphy LC. Regulation of steroid hormone receptors and coregulators during the cell cycle highlights potential novel function in addition to roles as transcription factors. NUCLEAR RECEPTOR SIGNALING 2016; 14:e001. [PMID: 26778927 PMCID: PMC4714463 DOI: 10.1621/nrs.14001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/01/2015] [Indexed: 01/15/2023]
Abstract
Cell cycle progression is tightly controlled by several kinase families including Cyclin-Dependent Kinases, Polo-Like Kinases, and Aurora Kinases. A large amount of data show that steroid hormone receptors and various components of the cell cycle, including cell cycle regulated kinases, interact, and this often results in altered transcriptional activity of the receptor. Furthermore, steroid hormones, through their receptors, can also regulate the transcriptional expression of genes that are required for cell cycle regulation. However, emerging data suggest that steroid hormone receptors may have roles in cell cycle progression independent of their transcriptional activity. The following is a review of how steroid receptors and their coregulators can regulate or be regulated by the cell cycle machinery, with a particular focus on roles independent of transcription in G2/M.
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Affiliation(s)
- Yingfeng Zheng
- Department of Biochemistry and Medical Genetics (YZ, LCM), University of Manitoba; Manitoba Institute of Cell Biology (YZ, LCM), CancerCare Manitoba, Winnipeg, Manitoba, Canada
| | - Leigh C Murphy
- Department of Biochemistry and Medical Genetics (YZ, LCM), University of Manitoba; Manitoba Institute of Cell Biology (YZ, LCM), CancerCare Manitoba, Winnipeg, Manitoba, Canada
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58
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Liu X, Han W, Gulla S, Simon NI, Gao Y, Cai C, Yang H, Zhang X, Liu J, Balk SP, Chen S. Protein phosphatase 1 suppresses androgen receptor ubiquitylation and degradation. Oncotarget 2016; 7:1754-64. [PMID: 26636645 PMCID: PMC4811495 DOI: 10.18632/oncotarget.6434] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/18/2015] [Indexed: 12/20/2022] Open
Abstract
The phosphoprotein phosphatases are emerging as important androgen receptor (AR) regulators in prostate cancer (PCa). We reported previously that the protein phosphatase 1 catalytic subunit (PP1α) can enhance AR activity by dephosphorylating a site in the AR hinge region (Ser650) and thereby decrease AR nuclear export. In this study we show that PP1α increases the expression of wildtype as well as an S650A mutant AR, indicating that it is acting through one or more additional mechanisms. We next show that PP1α binds primarily to the AR ligand binding domain and decreases its ubiquitylation and degradation. Moreover, we find that the PP1α inhibitor tautomycin increases phosphorylation of AR ubiquitin ligases including SKP2 and MDM2 at sites that enhance their activity, providing a mechanism by which PP1α may suppress AR degradation. Significantly, the tautomycin mediated decrease in AR expression was most pronounced at low androgen levels or in the presence of the AR antagonist enzalutamide. Consistent with this finding, the sensitivity of LNCaP and C4-2 PCa cells to tautomycin, as assessed by PSA synthesis and proliferation, was enhanced at low androgen levels or by treatment with enzalutamide. Together these results indicate that PP1α may contribute to stabilizing AR protein after androgen deprivation therapies, and that targeting PP1α or the AR-PP1α interaction may be effective in castration-resistant prostate cancer (CRPC).
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Affiliation(s)
- Xiaming Liu
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Weiwei Han
- Department of Urology, Union Hospital, Tongji Medical School, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Sarah Gulla
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Nicholas I. Simon
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Yanfei Gao
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Changmeng Cai
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Hongmei Yang
- Department of Pathogen Biology, Tongji Medical School, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoping Zhang
- Department of Urology, Union Hospital, Tongji Medical School, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jihong Liu
- Department of Urology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Steven P. Balk
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Shaoyong Chen
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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Mehraein-Ghomi F, Church DR, Schreiber CL, Weichmann AM, Basu HS, Wilding G. Inhibitor of p52 NF-κB subunit and androgen receptor (AR) interaction reduces growth of human prostate cancer cells by abrogating nuclear translocation of p52 and phosphorylated AR(ser81). Genes Cancer 2015; 6:428-44. [PMID: 26622945 PMCID: PMC4633170 DOI: 10.18632/genesandcancer.77] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Accumulating evidence shows that androgen receptor (AR) activation and signaling plays a key role in growth and progression in all stages of prostate cancer, even under low androgen levels or in the absence of androgen in the castration-resistant prostate cancer. Sustained activation of AR under androgen-deprived conditions may be due to its interaction with co-activators, such as p52 NF-κB subunit, and/or an increase in its stability by phosphorylation that delays its degradation. Here we identified a specific inhibitor of AR/p52 interaction, AR/p52-02, via a high throughput screen based on the reconstitution of Gaussia Luciferase. We found that AR/p52-02 markedly inhibited growth of both castration-resistant C4-2 (IC50 ∼6 μM) and parental androgen-dependent LNCaP (IC50 ∼4 μM) human prostate cancer cells under low androgen conditions. Growth inhibition was associated with significantly reduced nuclear p52 levels and DNA binding activity, as well as decreased phosphorylation of AR at serine 81, increased AR ubiquitination, and decreased AR transcriptional activity as indicated by decreased prostate-specific antigen (PSA) mRNA levels in both cell lines. AR/p52-02 also caused a reduction in levels of p21(WAF/CIP1), which is a direct AR targeted gene in that its expression correlates with androgen stimulation and mitogenic proliferation in prostate cancer under physiologic levels of androgen, likely by disrupting the AR signaling axis. The reduced level of cyclinD1 reported previously for this compound may be due to the reduction in nuclear presence and activity of p52, which directly regulates cyclinD1 expression, as well as the reduction in p21(WAF/CIP1), since p21(WAF/CIP1) is reported to stabilize nuclear cyclinD1 in prostate cancer. Overall, the data suggest that specifically inhibiting the interaction of AR with p52 and blocking activity of p52 and pARser81 may be an effective means of reducing castration-resistant prostate cancer cell growth.
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Affiliation(s)
| | - Dawn R Church
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin, USA
| | | | | | - Hirak S Basu
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin, USA
| | - George Wilding
- University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Wang T, Song W, Chen Y, Chen R, Liu Z, Wu L, Li M, Yang J, Wang L, Liu J, Ye Z, Wang C, Chen K. Flightless I Homolog Represses Prostate Cancer Progression through Targeting Androgen Receptor Signaling. Clin Cancer Res 2015; 22:1531-44. [PMID: 26527749 DOI: 10.1158/1078-0432.ccr-15-1632] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/25/2015] [Indexed: 11/16/2022]
Abstract
PURPOSE Flightless I (FLII), member of the gelsolin superfamily of actin-remodeling proteins, functions as a transcriptional coregulator. We aim to evaluate a tumor-suppressive function of FLII in regulating androgen receptor (AR) in prostate cancer progression. EXPERIMENTAL DESIGN We examined FLII protein and mRNA expression in clinical prostate cancer specimens by immunohistochemistry. Kaplan-Meier analysis was conducted to evaluate the difference in disease-overall survival associated with the expression levels of FLII and AR. Prostate cancer cells stably expressing FLII or shRNA knockdown were used for functional analyses. Immunoprecipitation, Luciferase reporter, and immunofluorescence staining assays were performed to examine the functional interaction between FLII and AR. RESULTS Our analysis of the expression levels of FLII in a clinical gene expression array dataset showed that the expression of FLII was positively correlated with the overall survival of prostate cancer patients exhibiting high levels of AR expression. Examination of protein and mRNA levels of FLII showed a significant decrease of FLII expression in human prostate cancers. AR and FLII formed a complex in a ligand-dependent manner through the ligand-binding domain (LBD) of AR. Subsequently, we observed a competitive binding to AR between FLII and the ligand. FLII inhibited AR transactivation and decreased AR nuclear localization. Furthermore, FLII contributed to castration-sensitive and castration-resistant prostate cancer cell growth through AR-dependent signaling, and reintroduction of FLII in prostate cancer cells sensitized the cells to bicalutamide and enzalutamide treatment. CONCLUSIONS FLII plays a tumor-suppressive role and serves as a crucial determinant of resistance of prostate cancer to endocrine therapies.
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Affiliation(s)
- Tao Wang
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wen Song
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yuan Chen
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ruibao Chen
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhuo Liu
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Licheng Wu
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Mingchao Li
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jun Yang
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Liang Wang
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jihong Liu
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhangqun Ye
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chenguang Wang
- Key Laboratory of Tianjin Radiation and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College & Chinese Academy of Medical Sciences, Tianjin, China
| | - Ke Chen
- Department of Urology, Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China. Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Krasnov GS, Dmitriev AA, Sadritdinova AF, Volchenko NN, Slavnova EN, Danilova TV, Snezhkina AV, Melnikova NV, Fedorova MS, Lakunina VA, Belova AA, Nyushko KM, Alekseev BY, Kaprin AD, Kudryavtseva AV. Molecular genetic mechanisms of drug resistance in prostate cancer. Mol Biol 2015. [DOI: 10.1134/s0026893315050118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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62
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Inhibition of IGF-1R diminishes transcriptional activity of the androgen receptor and its constitutively active, C-terminally truncated counterparts Q640X and AR-V7. World J Urol 2015; 34:633-9. [PMID: 26318637 DOI: 10.1007/s00345-015-1674-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/20/2015] [Indexed: 10/23/2022] Open
Abstract
PURPOSE Failure of endocrine treatment in castration-resistant prostate cancer (CRPC) is often associated with the emergence of C-terminally truncated androgen receptor variants that function as constitutively active transcription factors (i.e., AR∆LBD). The mechanisms involved in the regulation of AR∆LBD signaling are largely unknown. Since the IGF-1 pathway was repeatedly shown to affect AR function, we studied whether an inhibition of IGF-1R could also affect AR∆LBD signaling. METHODS Regulation of androgen receptor (AR) and AR∆LBD signaling was analyzed by reporter gene assays, immunoblotting, ELISA and quantitative RT-PCR. RESULTS Inhibition of IGF-1R with the small-molecule inhibitor NVP-AEW541 reduced the transcriptional activity of the AR and its truncated counterparts Q640X and AR-V7. As shown in Q640X, the inhibition of transcriptional activity was paralleled by a decreased receptor phosphorylation. CONCLUSIONS Inhibition of IGF-1R leads to a down-regulation of AR∆LBD signaling and provides a rationale for CRPC therapies targeting growth factor receptors.
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63
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Williamson M, de Winter P, Masters JR. Plexin-B1 signalling promotes androgen receptor translocation to the nucleus. Oncogene 2015; 35:1066-72. [DOI: 10.1038/onc.2015.160] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/18/2015] [Accepted: 03/03/2015] [Indexed: 12/22/2022]
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64
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Karaca M, Liu Y, Zhang Z, De Silva D, Parker JS, Earp HS, Whang YE. Mutation of androgen receptor N-terminal phosphorylation site Tyr-267 leads to inhibition of nuclear translocation and DNA binding. PLoS One 2015; 10:e0126270. [PMID: 25950519 PMCID: PMC4423977 DOI: 10.1371/journal.pone.0126270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/31/2015] [Indexed: 12/31/2022] Open
Abstract
Reactivation of androgen receptor (AR) may drive recurrent prostate cancer in castrate patients. Ack1 tyrosine kinase is overexpressed in prostate cancer and promotes castrate resistant xenograft tumor growth and enhances androgen target gene expression and AR recruitment to enhancers. Ack1 phosphorylates AR at Tyr-267 and possibly Tyr-363, both in the N-terminal transactivation domain. In this study, the role of these phosphorylation sites was investigated by characterizing the phosphorylation site mutants in the context of full length and truncated AR lacking the ligand-binding domain. Y267F and Y363F mutants showed decreased transactivation of reporters. Expression of wild type full length and truncated AR in LNCaP cells increased cell proliferation in androgen-depleted conditions and increased colony formation. However, the Y267F mutant of full length and truncated AR was defective in stimulating cell proliferation. The Y363F mutant was less severely affected than the Y267F mutant. The full length AR Y267F mutant was defective in nuclear translocation induced by androgen or Ack1 kinase. The truncated AR was constitutively localized to the nucleus. Chromatin immunoprecipitation analysis showed that it was recruited to the target enhancers without androgen. The truncated Y267F AR mutant did not exhibit constitutive nuclear localization and androgen enhancer binding activity. These results support the concept that phosphorylation of Tyr-267, and to a lesser extent Tyr-363, is required for AR nuclear translocation and recruitment and DNA binding and provide a rationale for development of novel approaches to inhibit AR activity.
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Affiliation(s)
- Mehmet Karaca
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
| | - Yuanbo Liu
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
- Department of Hematology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Zhentao Zhang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
| | - Dinuka De Silva
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
| | - Joel S. Parker
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - H. Shelton Earp
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - Young E. Whang
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States of America
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
- * E-mail:
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65
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Lindqvist J, Imanishi SY, Torvaldson E, Malinen M, Remes M, Örn F, Palvimo JJ, Eriksson JE. Cyclin-dependent kinase 5 acts as a critical determinant of AKT-dependent proliferation and regulates differential gene expression by the androgen receptor in prostate cancer cells. Mol Biol Cell 2015; 26:1971-84. [PMID: 25851605 PMCID: PMC4472009 DOI: 10.1091/mbc.e14-12-1634] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/31/2015] [Indexed: 12/25/2022] Open
Abstract
CDK5 acts as a signaling hub in prostate cancer cells by controlling androgen responses through AR stabilization and specific gene targeting, maintaining and accelerating cell proliferation through activation of the oncogenic AKT kinase, and releasing cell cycle breaks in a variety of prostate cancer cell lines. Contrary to cell cycle–associated cyclin-dependent kinases, CDK5 is best known for its regulation of signaling processes in differentiated cells and its destructive activation in Alzheimer's disease. Recently, CDK5 has been implicated in a number of different cancers, but how it is able to stimulate cancer-related signaling pathways remains enigmatic. Our goal was to study the cancer-promoting mechanisms of CDK5 in prostate cancer. We observed that CDK5 is necessary for proliferation of several prostate cancer cell lines. Correspondingly, there was considerable growth promotion when CDK5 was overexpressed. When examining the reasons for the altered proliferation effects, we observed that CDK5 phosphorylates S308 on the androgen receptor (AR), resulting in its stabilization and differential expression of AR target genes including several growth-priming transcription factors. However, the amplified cell growth was found to be separated from AR signaling, further corroborated by CDK5-depdent proliferation of AR null cells. Instead, we found that the key growth-promoting effect was due to specific CDK5-mediated AKT activation. Down-regulation of CDK5 repressed AKT phosphorylation by altering its intracellular localization, immediately followed by prominent cell cycle inhibition. Taken together, these results suggest that CDK5 acts as a crucial signaling hub in prostate cancer cells by controlling androgen responses through AR, maintaining and accelerating cell proliferation through AKT activation, and releasing cell cycle breaks.
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Affiliation(s)
- Julia Lindqvist
- Department of Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI-20520 Turku, Finland
| | - Susumu Y Imanishi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI-20520 Turku, Finland
| | - Elin Torvaldson
- Department of Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI-20520 Turku, Finland
| | - Marjo Malinen
- Institute of Biomedicine/Medical Biochemistry, University of Eastern Finland, and Department of Pathology, Kuopio University Hospital, FI-70211 Kuopio, Finland
| | - Mika Remes
- Department of Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland
| | - Fanny Örn
- Department of Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI-20520 Turku, Finland
| | - Jorma J Palvimo
- Institute of Biomedicine/Medical Biochemistry, University of Eastern Finland, and Department of Pathology, Kuopio University Hospital, FI-70211 Kuopio, Finland
| | - John E Eriksson
- Department of Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI-20520 Turku, Finland
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66
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Abstract
The androgen receptor (AR) is a critical oncogene in prostate cancer (PCa) development and progression. In this study, we demonstrate cell-cycle-dependent regulation of AR activity, localization, and phosphorylation. We show that for three AR-target genes, androgen-stimulated AR transactivation is highest during the G1 phase, decreased during S-phase, and abrogated during G2/M. This change in AR transactivation parallels changes in AR localization and phosphorylation. A combination of imaging techniques and quantitative analysis reveals nuclear AR localization during interphase and the exclusion of the majority, but not all, AR from chromatin during mitosis. Flow cytometry analyses using a phospho-S308 AR-specific antibody in asynchronous and chemically enriched G2/M PCa cells revealed ligand-independent induction of S308 phosphorylation in mitosis when CDK1 is activated. Consistent with our flow cytometry data, IP-western blotting revealed an increase in S308 phosphorylation in G2/M, and the results of an in vitro kinase assay indicated that CDK1 was able to phosphorylate the AR on S308. Pharmacological inhibition of CDK1 activity resulted in decreased S308 phosphorylation in PCa cells. Importantly, using a combination of anti-total AR and phospho-S308-specific antibodies in immunofluorescence experiments, we showed that the AR is excluded from condensed chromatin in mitotic cells when it was phosphorylated on S308. In summary, we show that the phosphorylation of the AR on S308 by CDK1 during mitosis regulates AR localization and correlates with changes in AR transcriptional activity. These findings have important implications for understanding the function of AR as an oncogene.
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Affiliation(s)
- Yulia Koryakina
- Department of MicrobiologyImmunology, and Cancer Biology, University of Virginia, Jordan Hall Room 2-16, 1300 Jefferson Park Avenue, PO Box 800734, Charlottesville, Virginia 22908, USASidney Kimmel Cancer CenterThomas Jefferson University, Philadelphia, Pennsylvania, USACancer Center MemberUniversity of Virginia, Charlottesville, Virginia, USA
| | - Karen E Knudsen
- Department of MicrobiologyImmunology, and Cancer Biology, University of Virginia, Jordan Hall Room 2-16, 1300 Jefferson Park Avenue, PO Box 800734, Charlottesville, Virginia 22908, USASidney Kimmel Cancer CenterThomas Jefferson University, Philadelphia, Pennsylvania, USACancer Center MemberUniversity of Virginia, Charlottesville, Virginia, USA
| | - Daniel Gioeli
- Department of MicrobiologyImmunology, and Cancer Biology, University of Virginia, Jordan Hall Room 2-16, 1300 Jefferson Park Avenue, PO Box 800734, Charlottesville, Virginia 22908, USASidney Kimmel Cancer CenterThomas Jefferson University, Philadelphia, Pennsylvania, USACancer Center MemberUniversity of Virginia, Charlottesville, Virginia, USA Department of MicrobiologyImmunology, and Cancer Biology, University of Virginia, Jordan Hall Room 2-16, 1300 Jefferson Park Avenue, PO Box 800734, Charlottesville, Virginia 22908, USASidney Kimmel Cancer CenterThomas Jefferson University, Philadelphia, Pennsylvania, USACancer Center MemberUniversity of Virginia, Charlottesville, Virginia, USA
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67
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Abstract
Androgens and androgen receptor (AR) signaling are necessary for prostate development and homeostasis. AR signaling also drives the growth of nearly all prostate cancer cells. The role of androgens and AR signaling has been well characterized in metastatic prostate cancer, where it has been shown that prostate cancer cells are exquisitely adept at maintaining functional AR signaling to drive cancer growth. As androgens and AR signaling are so intimately involved in prostate development and the proliferation of advanced prostate cancer, it stands to reason that androgens and AR are also involved in prostate cancer initiation and the early stages of cancer growth, yet little is known of this process. In this review, we summarize the current state of knowledge concerning the role of androgens and AR signaling in prostate tissue, from development to metastatic, castration-resistant prostate cancer, and use that information to suggest potential roles for androgens and AR in prostate cancer initiation.
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Affiliation(s)
- Ye Zhou
- Department of Molecular PharmacologyBeckman Research Institute, City of Hope National Medical Center, 1500 E Duarte Road, Beckman 2310, Duarte, California 91010, USADepartment of Molecular and Integrative PhysiologyUniversity of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Eric C Bolton
- Department of Molecular PharmacologyBeckman Research Institute, City of Hope National Medical Center, 1500 E Duarte Road, Beckman 2310, Duarte, California 91010, USADepartment of Molecular and Integrative PhysiologyUniversity of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Jeremy O Jones
- Department of Molecular PharmacologyBeckman Research Institute, City of Hope National Medical Center, 1500 E Duarte Road, Beckman 2310, Duarte, California 91010, USADepartment of Molecular and Integrative PhysiologyUniversity of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Koryakina Y, Ta HQ, Gioeli D. Androgen receptor phosphorylation: biological context and functional consequences. Endocr Relat Cancer 2014; 21:T131-45. [PMID: 24424504 PMCID: PMC4437516 DOI: 10.1530/erc-13-0472] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [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
The androgen receptor (AR) is a ligand-regulated transcription factor that belongs to the family of nuclear receptors. In addition to regulation by steroid, the AR is also regulated by post-translational modifications generated by signal transduction pathways. Thus, the AR functions not only as a transcription factor but also as a node that integrates multiple extracellular signals. The AR plays an important role in many diseases, including complete androgen insensitivity syndrome, spinal bulbar muscular atrophy, prostate and breast cancer, etc. In the case of prostate cancer, dependence on AR signaling has been exploited for therapeutic intervention for decades. However, the effectiveness of these therapies is limited in advanced disease due to restoration of AR signaling. Greater understanding of the molecular mechanisms involved in AR action will enable the development of improved therapeutics to treat the wide range of AR-dependent diseases. The AR is subject to regulation by a number of kinases through post-translational modifications on serine, threonine, and tyrosine residues. In this paper, we review the AR phosphorylation sites, the kinases responsible for these phosphorylations, as well as the biological context and the functional consequences of these phosphorylations. Finally, what is known about the state of AR phosphorylation in clinical samples is discussed.
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Affiliation(s)
- Yulia Koryakina
- Department of MicrobiologyImmunology, and Cancer BiologyUVA Cancer CenterUniversity of Virginia, PO Box 800734, Charlottesville, Virginia 22908, USA
| | - Huy Q Ta
- Department of MicrobiologyImmunology, and Cancer BiologyUVA Cancer CenterUniversity of Virginia, PO Box 800734, Charlottesville, Virginia 22908, USA
| | - Daniel Gioeli
- Department of MicrobiologyImmunology, and Cancer BiologyUVA Cancer CenterUniversity of Virginia, PO Box 800734, Charlottesville, Virginia 22908, USADepartment of MicrobiologyImmunology, and Cancer BiologyUVA Cancer CenterUniversity of Virginia, PO Box 800734, Charlottesville, Virginia 22908, USA
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69
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Kahn B, Collazo J, Kyprianou N. Androgen receptor as a driver of therapeutic resistance in advanced prostate cancer. Int J Biol Sci 2014; 10:588-95. [PMID: 24948871 PMCID: PMC4062951 DOI: 10.7150/ijbs.8671] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/01/2014] [Indexed: 12/21/2022] Open
Abstract
The role of the androgen receptor (AR) signaling axis in the progression of prostate cancer is a cornerstone to our understanding of the molecular mechanisms causing castration-resistant prostate cancer (CRPC). Resistance of advanced prostate cancer to available treatment options makes it a clinical challenge that results in approximately 30,000 deaths of American men every year. Since the historic discovery by Dr. Huggins more than 70 years ago, androgen deprivation therapy (ADT) has been the principal treatment for advanced prostate cancer. Initially, ADT induces apoptosis of androgen-dependent prostate cancer epithelial cells and regression of androgen-dependent tumors. However, the majority of patients with advanced prostate cancer progress and become refractory to ADT due to emergence of androgen-independent prostate cancer cells driven by aberrant AR activation. Microtubule-targeting agents such as taxanes, docetaxel and paclitaxel, have enjoyed success in the treatment of metastatic prostate cancer; although new, recently designed mitosis-specific agents, such as the polo-kinase and kinesin-inhibitors, have yielded clinically disappointing results. Docetaxel, as a first-line chemotherapy, improves prostate cancer patient survival by months, but tumor resistance to these therapeutic agents inevitably develops. On a molecular level, progression to CRPC is characterized by aberrant AR expression, de novo intraprostatic androgen production, and cross talk with other oncogenic pathways. Emerging evidence suggests that reactivation of epithelial-mesenchymal-transition (EMT) processes may facilitate the development of not only prostate cancer but also prostate cancer metastases. EMT is characterized by gain of mesenchymal characteristics and invasiveness accompanied by loss of cell polarity, with an increasing number of studies focusing on the direct involvement of androgen-AR signaling axis in EMT, tumor progression, and therapeutic resistance. In this article, we discuss the current knowledge of mechanisms via which the AR signaling drives therapeutic resistance in prostate cancer metastatic progression and the novel therapeutic interventions targeting AR in CRPC.
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Affiliation(s)
| | | | - Natasha Kyprianou
- Departments of Urology and Molecular and Cellular Biochemistry, University of Kentucky, College of Medicine, Lexington, KY 40536, USA
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70
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Yu Z, Cai C, Gao S, Simon NI, Shen HC, Balk SP. Galeterone prevents androgen receptor binding to chromatin and enhances degradation of mutant androgen receptor. Clin Cancer Res 2014; 20:4075-85. [PMID: 24874833 DOI: 10.1158/1078-0432.ccr-14-0292] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Galeterone inhibits the enzyme CYP17A1 and is currently in phase II clinical trials for castration-resistant prostate cancer (CRPC). Galeterone is also a direct androgen receptor (AR) antagonist and may enhance AR degradation. This study was undertaken to determine the molecular basis for AR effects and their therapeutic potential. EXPERIMENTAL DESIGN Effects of galeterone on AR expression and activities were examined in prostate cancer cell lines. RESULTS Similar to the AR antagonist enzalutamide, but in contrast to bicalutamide, galeterone did not induce binding of a constitutively active VP16-AR fusion protein to reporter genes and did not induce AR recruitment to endogenous androgen-regulated genes based on chromatin immunoprecipitation. Galeterone at low micromolar concentrations that did not induce cellular stress responses enhanced AR protein degradation in LNCaP and C4-2 cells, which express a T878A mutant AR, but not in prostate cancer cells expressing wild-type AR. Further transfection studies using stable LNCaP and PC3 cell lines ectopically expressing wild-type or T878A-mutant ARs confirmed that galeterone selectively enhances degradation of the T878A-mutant AR. CONCLUSIONS Similar to enzalutamide, galeterone may be effective as a direct AR antagonist in CRPC. It may be particularly effective against prostate cancer cells with the T878A AR mutation but may also enhance degradation of wild-type AR in vivo through a combination of direct and indirect mechanisms. Finally, these findings show that conformational changes in AR can markedly enhance its degradation and thereby support efforts to develop further antagonists that enhance AR degradation.
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Affiliation(s)
- Ziyang Yu
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Changmeng Cai
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Shuai Gao
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Nicholas I Simon
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Howard C Shen
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Steven P Balk
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
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71
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Yuan X, Cai C, Chen S, Chen S, Yu Z, Balk SP. Androgen receptor functions in castration-resistant prostate cancer and mechanisms of resistance to new agents targeting the androgen axis. Oncogene 2014; 33:2815-25. [PMID: 23752196 PMCID: PMC4890635 DOI: 10.1038/onc.2013.235] [Citation(s) in RCA: 261] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 12/17/2022]
Abstract
The metabolic functions of androgen receptor (AR) in normal prostate are circumvented in prostate cancer (PCa) to drive tumor growth, and the AR also can acquire new growth-promoting functions during PCa development and progression through genetic and epigenetic mechanisms. Androgen deprivation therapy (ADT, surgical or medical castration) is the standard treatment for metastatic PCa, but patients invariably relapse despite castrate androgen levels (castration-resistant PCa, CRPC). Early studies from many groups had shown that AR was highly expressed and transcriptionally active in CRPC, and indicated that steroids from the adrenal glands were contributing to this AR activity. More recent studies showed that CRPC cells had increased expression of enzymes mediating androgen synthesis from adrenal steroids, and could synthesize androgens de novo from cholesterol. Phase III clinical trials showing a survival advantage in CRPC for treatment with abiraterone (inhibitor of the enzyme CYP17A1 required for androgen synthesis that markedly reduces androgens and precursor steroids) and for enzalutamide (new AR antagonist) have now confirmed that AR activity driven by residual androgens makes a major contribution to CRPC, and led to the recent Food and Drug Administration approval of both agents. Unfortunately, patients treated with these agents for advanced CRPC generally relapse within a year and AR appears to be active in the relapsed tumors, but the molecular mechanisms mediating intrinsic or acquired resistance to these AR-targeted therapies remain to be defined. This review outlines AR functions that contribute to PCa development and progression, the roles of intratumoral androgen synthesis and AR structural alterations in driving AR activity in CRPC, mechanisms of action for abiraterone and enzalutamide, and possible mechanisms of resistance to these agents.
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MESH Headings
- Androgen Receptor Antagonists/therapeutic use
- Androgens/metabolism
- Animals
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Disease Progression
- Drug Resistance, Neoplasm
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Prostatic Neoplasms, Castration-Resistant/drug therapy
- Prostatic Neoplasms, Castration-Resistant/genetics
- Prostatic Neoplasms, Castration-Resistant/metabolism
- Receptors, Androgen/chemistry
- Receptors, Androgen/metabolism
- Repressor Proteins/metabolism
- Steroid 17-alpha-Hydroxylase/antagonists & inhibitors
- Steroid 17-alpha-Hydroxylase/metabolism
- Trans-Activators/metabolism
- Transcription, Genetic
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Affiliation(s)
- X Yuan
- Hematology Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - C Cai
- Hematology Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - S Chen
- Hematology Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - S Chen
- Hematology Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Z Yu
- Hematology Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - S P Balk
- Hematology Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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72
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Zhu R, Lu X, Pradhan M, Armstrong S, Storchan GB, Chow C, Simons SS. A kinase-independent activity of Cdk9 modulates glucocorticoid receptor-mediated gene induction. Biochemistry 2014; 53:1753-67. [PMID: 24559102 PMCID: PMC3985961 DOI: 10.1021/bi5000178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/20/2014] [Indexed: 12/18/2022]
Abstract
A gene induction competition assay has recently uncovered new inhibitory activities of two transcriptional cofactors, NELF-A and NELF-B, in glucocorticoid-regulated transactivation. NELF-A and -B are also components of the NELF complex, which participates in RNA polymerase II pausing shortly after the initiation of gene transcription. We therefore asked if cofactors (Cdk9 and ELL) best known to affect paused polymerase could reverse the effects of NELF-A and -B. Unexpectedly, Cdk9 and ELL augmented, rather than prevented, the effects of NELF-A and -B. Furthermore, Cdk9 actions are not blocked either by Ckd9 inhibitors (DRB or flavopiridol) or by two Cdk9 mutants defective in kinase activity. The mode and site of action of NELF-A and -B mutants with an altered NELF domain are similarly affected by wild-type and kinase-dead Cdk9. We conclude that Cdk9 is a new modulator of GR action, that Ckd9 and ELL have novel activities in GR-regulated gene expression, that NELF-A and -B can act separately from the NELF complex, and that Cdk9 possesses activities that are independent of Cdk9 kinase activity. Finally, the competition assay has succeeded in ordering the site of action of several cofactors of GR transactivation. Extension of this methodology should be helpful in determining the site and mode of action of numerous additional cofactors and in reducing unwanted side effects.
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Affiliation(s)
- Rong Zhu
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Xinping Lu
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Madhumita Pradhan
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Stephen
P. Armstrong
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Geoffrey B. Storchan
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Carson
C. Chow
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - S. Stoney Simons
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
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73
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Pinto Á. Beyond abiraterone: new hormonal therapies for metastatic castration-resistant prostate cancer. Cancer Biol Ther 2014; 15:149-55. [PMID: 24100689 PMCID: PMC3928129 DOI: 10.4161/cbt.26724] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 09/10/2013] [Accepted: 10/06/2013] [Indexed: 11/19/2022] Open
Abstract
Prostate cancer is a heterogeneous disease where the previous concept of "hormone resistance" has been changed by a new generation of hormonal therapies that have proven efficacy in the castration-resistant setting. The fact is that androgens play a crucial role in the whole clinical course of prostate cancer, even when a patient meets castration-resistance criteria. The development of abiraterone showed how important and clinically meaningful can be to achieve the lowest possible levels of testosterone, and androgen receptor overexpression, mutation, or enhanced crosstalk with other pathways, which can also be targeted with new agents tested in the last few years. New androgen biosynthesis inhibitors have been developed, such as orteronel (TAK-700), but also new antiandrogens (enzalutamide, ARN-509, ODM-201) or even agents with a dual mechanism of action (galeterone). In this review the development of new hormonal therapies following the arrival of abiraterone for the treatment of prostate cancer will be summarized.
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Affiliation(s)
- Álvaro Pinto
- Medical Oncology Department; University Hospital La Paz; IdiPAZ; Madrid, Spain
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74
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Zhong J, Ding L, Bohrer LR, Pan Y, Liu P, Zhang J, Sebo TJ, Karnes RJ, Tindall DJ, van Deursen J, Huang H. p300 acetyltransferase regulates androgen receptor degradation and PTEN-deficient prostate tumorigenesis. Cancer Res 2014; 74:1870-1880. [PMID: 24480624 DOI: 10.1158/0008-5472.can-13-2485] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Overexpression of the histone acetyltransferase p300 is implicated in the proliferation and progression of prostate cancer, but evidence of a causal role is lacking. In this study, we provide genetic evidence that this generic transcriptional coactivator functions as a positive modifier of prostate tumorigenesis. In a mouse model of PTEN deletion-induced prostate cancer, genetic ablation of p300 attenuated expression of the androgen receptor (AR). This finding was confirmed in human prostate cancer cells in which PTEN expression was abolished by RNA interference-mediated attenuation. These results were consistent with clinical evidence that the expression of p300 and AR correlates positively in human prostate cancer specimens. Mechanistically, PTEN inactivation increased AR phosphorylation at serine 81 (Ser81) to promote p300 binding and acetylation of AR, thereby precluding its polyubiquitination and degradation. In support of these findings, in PTEN-deficient prostate cancer in the mouse, we found that p300 was crucial for AR target gene expression. Taken together, our work identifies p300 as a molecular determinant of AR degradation and highlights p300 as a candidate target to manage prostate cancer, especially in cases marked by PTEN loss.
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Affiliation(s)
- Jian Zhong
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Department of Urology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Mayo Clinic Cancer Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Liya Ding
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Department of Urology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Mayo Clinic Cancer Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Laura R Bohrer
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yunqian Pan
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Ping Liu
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jun Zhang
- Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Thomas J Sebo
- Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - R Jeffrey Karnes
- Department of Urology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Donald J Tindall
- Department of Urology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Mayo Clinic Cancer Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Jan van Deursen
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Mayo Clinic Cancer Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Haojie Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Department of Urology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.,Mayo Clinic Cancer Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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75
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Daniels G, Pei Z, Logan SK, Lee P. Mini-review: androgen receptor phosphorylation in prostate cancer. AMERICAN JOURNAL OF CLINICAL AND EXPERIMENTAL UROLOGY 2013; 1:25-29. [PMID: 25374897 PMCID: PMC4219286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 12/15/2013] [Indexed: 06/04/2023]
Abstract
Androgen receptor (AR) plays an important role in the tumorigenesis and progression of prostate cancer (PCa), and is the primary therapeutic target for PCa treatment. AR activity can be regulated via phosphorylation at multiple phosphorylation sites within the protein. Modifications by phosphorylation alter AR function, including its cellular localization, stability and transcriptional activity, ultimately leading to changes in cancer cell biology and disease progression. Here we present a brief overview of AR phosphorylation sites in PCa, focusing on functional roles of phospho-AR (p-AR) species, relevance in PCa disease progression, and potential as biomarkers and/or therapeutic targets through the use of kinase inhibitors. Additionally, recent evidence has shown the important role of AR activity in the cancer associated stroma on PCa growth and progression. The phosphorylation status of epithelial and stromal AR may be distinct; however, the current data available on stromal AR phosphorylation is limited. Further research will determine global view on the synergistic effects of phosphorylation across multiple AR sites in both epithelial and stromal cells and validate whether together they can be used as prognostic markers and/or effective therapeutic targets for PCa.
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Affiliation(s)
- Garrett Daniels
- Department of Pathology, New York University School of MedicineNew York, NY, USA
| | - Zhiheng Pei
- Department of Pathology, New York University School of MedicineNew York, NY, USA
- NYU Cancer Institute, New York University School of MedicineNew York, NY, USA
- New York Harbor Healthcare System, New York University School of MedicineNew York, NY, USA
| | - Susan K Logan
- Department of Urology, New York University School of Medicine, New YorkNY, USA
- Department of Pharmacology, New York University School of MedicineNew York, NY, USA
- NYU Cancer Institute, New York University School of MedicineNew York, NY, USA
| | - Peng Lee
- Department of Pathology, New York University School of MedicineNew York, NY, USA
- Department of Urology, New York University School of Medicine, New YorkNY, USA
- NYU Cancer Institute, New York University School of MedicineNew York, NY, USA
- New York Harbor Healthcare System, New York University School of MedicineNew York, NY, USA
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76
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Amin KS, Jagadeesh S, Baishya G, Rao PG, Barua NC, Bhattacharya S, Banerjee PP. A naturally derived small molecule disrupts ligand-dependent and ligand-independent androgen receptor signaling in human prostate cancer cells. Mol Cancer Ther 2013; 13:341-52. [PMID: 24258347 DOI: 10.1158/1535-7163.mct-13-0478] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Continued reliance on androgen receptor (AR) signaling is a hallmark of prostate cancer, including the development of castration-resistant prostate cancer (CRPC), making it an attractive therapeutic target for prostate cancer treatment. Mahanine is a novel carbazole alkaloid derived from the leaves of Murraya koenigii, commonly known as the curry leaf plant, which grows widely across East-Asia. We show here that mahanine possesses the ability to inhibit ligand-dependent and -independent AR transactivation, leading to a prominent decline in AR target gene expression. Mahanine treatment causes a time- and dose-dependent decline in AR protein levels, including truncated AR splice variants, in a panel of androgen-responsive and -independent prostate cancer cells. The decrease in AR levels induced by mahanine occurs posttranslationally by proteasomal degradation, without any change in the AR gene expression. Mahanine treatment induces an outward movement of the AR from the nucleus to the cytoplasm, leading to an initial increase in cytoplasmic AR levels, followed by a gradual decline in the AR levels in both cellular compartments. Ligand-induced AR phosphorylation at Ser-81, a phospho-site associated with prostate cancer cell growth and AR transactivity, is greatly diminished in the presence of mahanine. The decline in AR phosphorylation at Ser-81 by mahanine occurs via the inactivation of mitotic kinase CDK1. Collectively, our data demonstrate that mahanine strongly disrupts AR signaling and inhibits the growth of androgen-dependent and -independent prostate cancer cells, thereby implicating a therapeutic role of mahanine in prostate cancer treatment.
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Affiliation(s)
- Karishma S Amin
- Corresponding Author: Partha P. Banerjee, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20057.
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77
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Elias A, High AA, Mishra A, Ong SS, Wu J, Peng J, Chen T. Identification and characterization of phosphorylation sites within the pregnane X receptor protein. Biochem Pharmacol 2013; 87:360-70. [PMID: 24184507 DOI: 10.1016/j.bcp.2013.10.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/17/2013] [Accepted: 10/18/2013] [Indexed: 01/06/2023]
Abstract
Pregnane X receptor (PXR) is a xenobiotic sensor regulating the expression of genes involved in xenobiotic detoxification and elimination. Phosphorylation plays an important role in modulating PXR activity and several phosphorylation sites have been predicted and characterized in in vitro experiments. Although PXR has been shown to be a phosphoprotein in vivo, the exact residues that are phosphorylated remain elusive. Using mass spectrometry, we identified for the first time S114, T133/135, S167, and S200 residues that are phosphorylated in PXR following an in vitro kinase assay using cyclin-dependent kinase 2. We further found that the phosphorylation at S114, T133, and T135 occurred in PXR isolated from cells. We tested the phosphodeficient and phosphomimetic mutants corresponding to all the sites identified and determined that phosphorylation at S114 attenuates the transcriptional activity of PXR, consistent with the observation that the S114D mutant displayed reduced association with the PXR-targeted DNA response element. Phosphomimetic mutations at either T133 or T135 did not show a significant change in transcriptional activity however, the dual phosphomimetic mutant T133D/T135D displayed reduced transcriptional activity. Subcellular localization studies showed a varied distribution of the mutants suggesting that the regulation of PXR is much more complex than what we can observe by just overexpressing the mutants. Thus, our results provide the first direct evidence that PXR is phosphorylated at specific residues and suggest that further investigation is warranted to fully understand the regulation of PXR by phosphorylation.
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Affiliation(s)
- Ayesha Elias
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Anthony A High
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Ashutosh Mishra
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Su Sien Ong
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Jing Wu
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Junmin Peng
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Departments of Structural Biology and Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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78
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Treviño LS, Weigel NL. Phosphorylation: a fundamental regulator of steroid receptor action. Trends Endocrinol Metab 2013; 24:515-24. [PMID: 23838532 PMCID: PMC3783573 DOI: 10.1016/j.tem.2013.05.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/21/2013] [Accepted: 05/29/2013] [Indexed: 12/23/2022]
Abstract
Steroid hormone receptors (SHRs) are hormone-activated transcription factors involved in numerous cellular functions and in health and disease. Their activities depend on the cellular level of the receptor, the presence of coregulator proteins, and the cell signaling pathways that are active in the cell. SHRs and their coregulators are phosphorylated on multiple sites by a wide variety of kinases. Each site may contribute to multiple functions and the net effect of an individual phosphorylation depends on the activating kinase. Here we discuss functions of known SHR phosphorylation sites, kinase regulation, evidence of translational relevance, and crosstalk between SHRs and cell signaling pathways. Understanding how cell signaling pathways regulate SHRs might yield novel therapeutic targets for multiple human diseases.
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Affiliation(s)
- Lindsey S Treviño
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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79
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Egan A, Dong Y, Zhang H, Qi Y, Balk SP, Sartor O. Castration-resistant prostate cancer: adaptive responses in the androgen axis. Cancer Treat Rev 2013; 40:426-33. [PMID: 24139549 DOI: 10.1016/j.ctrv.2013.09.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/06/2013] [Indexed: 12/22/2022]
Abstract
The androgen signaling axis in prostate cancer is associated with multiple adaptive mechanisms in response to castration. Herein we review these adaptations with an emphasis on recent molecular insights into the growth and development of castration resistant prostate cancer (CRPC). Alterations include both conventional and novel intracrine androgen synthesis pathways and androgen transport as well as androgen receptor (AR) overexpression, mutation, and splice variation. Each of these underlying mechanisms are potentially linked to post-castration growth, especially after treatment with newer hormonal agents such as abiraterone and enzalutamide. Post-translational AR modifications are well documented and these can affect receptor activity, stability, localization, and interaction with other proteins. Changes in recruitment of androgen receptor associated co-activators/repressors and a distinct AR-induced transcriptional program can dramatically alter proliferation, invasion, and metastasis in a ligand and context-dependent manner. Numerous previously uncharacterized non-coding RNAs, some of which are androgen regulated, may also have important biological function in this disease. Taken together, the view of CRPC has changed dramatically in the last several years. This has occurred not only within the setting of multiple treatment paradigm changes, but also as a multiplicity of potential molecular mechanisms underlying this disease state have been explored and discovered.
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Affiliation(s)
- Alison Egan
- Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Yan Dong
- Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Department of Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA; National Engineering Laboratory for AIDS Vaccine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Haitao Zhang
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA; Department of Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Yanfeng Qi
- Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Department of Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Steven P Balk
- College of Life Sciences, Jilin University, China and Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Oliver Sartor
- Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA; Department of Urology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Department of Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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80
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Abstract
Prostate cancer (PCa) is the most commonly diagnosed noncutaneous malignancy and second leading cause of cancer-related deaths in US males. Clinically, locally confined disease is treated surgically and/or with radiation therapy. Invasive disease, however, must be treated with pharmacological inhibitors of androgen receptor (AR) activity, since disease progression is fundamentally reliant on AR activation. However, despite initially effective treatment options, recurrent castration-resistant PCa (CRPC) often occurs due to aberrant reactivation of AR. Additionally, it is appreciated that many other signaling molecules, such as transcription factors, oncogenes, and tumor suppressors, are often perturbed and significantly contribute to PCa initiation and progression to incurable disease. Understanding the interplay between AR signaling and other signaling networks altered in PCa will advance therapeutic approaches. Overall, comprehension of the molecular composition promoting neoplastic growth and formation of CRPC is paramount for developing durable treatment options.
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Affiliation(s)
- Randy Schrecengost
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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81
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van der Steen T, Tindall DJ, Huang H. Posttranslational modification of the androgen receptor in prostate cancer. Int J Mol Sci 2013; 14:14833-59. [PMID: 23863692 PMCID: PMC3742275 DOI: 10.3390/ijms140714833] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 01/03/2023] Open
Abstract
The androgen receptor (AR) is important in the development of the prostate by regulating transcription, cellular proliferation, and apoptosis. AR undergoes posttranslational modifications that alter its transcription activity, translocation to the nucleus and stability. The posttranslational modifications that regulate these events are of utmost importance to understand the functional role of AR and its activity. The majority of these modifications occur in the activation function-1 (AF1) region of the AR, which contains the transcriptional activation unit 1 (TAU1) and 5 (TAU5). Identification of the modifications that occur to these regions may increase our understanding of AR activation in prostate cancer and the role of AR in the progression from androgen-dependent to castration-resistant prostate cancer (CRPC). Most of the posttranslational modifications identified to date have been determined using the full-length AR in androgen dependent cells. Further investigations into the role of posttranslational modifications in androgen-independent activation of full-length AR and constitutively active splicing variants are warranted, findings from which may provide new therapeutic options for CRPC.
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Affiliation(s)
- Travis van der Steen
- Department of Urology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; E-Mails: (T.V.S.); (D.J.T.)
| | - Donald J. Tindall
- Department of Urology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; E-Mails: (T.V.S.); (D.J.T.)
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Haojie Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-507-284-0020; Fax: +1-507-293-3071
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82
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Wu K, Liu J, Tseng SF, Gore C, Ning Z, Sharifi N, Fazli L, Gleave M, Kapur P, Xiao G, Sun X, Oz OK, Min W, Alexandrakis G, Yang CR, Hsieh CL, Wu HC, He D, Xie D, Hsieh JT. The role of DAB2IP in androgen receptor activation during prostate cancer progression. Oncogene 2013; 33:1954-63. [PMID: 23604126 DOI: 10.1038/onc.2013.143] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 01/30/2013] [Accepted: 02/26/2013] [Indexed: 11/09/2022]
Abstract
Altered androgen-receptor (AR) expression and/or constitutively active AR are commonly associated with prostate cancer (PCa) progression. Targeting AR remains a focal point for designing new strategy of PCa therapy. Here, we have shown that DAB2IP, a novel tumor suppressor in PCa, can inhibit AR-mediated cell growth and gene activation in PCa cells via distinct mechanisms. DAB2IP inhibits the genomic pathway by preventing AR nuclear translocation or phosphorylation and suppresses the non-genomic pathway via its unique functional domain to inactivate c-Src. Also, DAB2IP is capable of suppressing AR activation in an androgen-independent manner. In addition, DAB2IP can inhibit several AR splice variants showing constitutive activity in PCa cells. In DAB2IP(-/-) mice, the prostate gland exhibits hyperplastic epithelia, in which AR becomes more active. Consistently, DAB2IP expression inversely correlates with AR activation status particularly in recurrent or metastatic PCa patients. Taken together, DAB2IP is a unique intrinsic AR modulator in normal cells, and likely can be further developed into a therapeutic agent for PCa.
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Affiliation(s)
- K Wu
- 1] Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA [2] Department of Urology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - J Liu
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - S-F Tseng
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - C Gore
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Z Ning
- Department of Urology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - N Sharifi
- Division of Hematology/Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - L Fazli
- Vancouver Prostate Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - M Gleave
- Vancouver Prostate Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - P Kapur
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - G Xiao
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - X Sun
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - O K Oz
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - W Min
- Interdepartmental Program in Vascular Biology and Transplantation and Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - G Alexandrakis
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - C-R Yang
- Department of Urology, China Medical University Hospital, Taichung, Taiwan
| | - C-L Hsieh
- 1] Graduate Institute of Cancer Biology, China Medical University Hospital, Taichung, Taiwan [2] Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan [3] Department of Biotechnology, Asia University, Taichung, Taiwan
| | - H-C Wu
- 1] Department of Urology, China Medical University Hospital, Taichung, Taiwan [2] School of Medicine, China Medical University, Taichung, Taiwan
| | - D He
- Department of Urology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - D Xie
- Department of General Surgery, Tongji Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - J-T Hsieh
- 1] Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA [2] Graduate Institute of Cancer Biology, China Medical University Hospital, Taichung, Taiwan
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83
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Abstract
The androgen receptor (AR) has been identified for decades and mediates essential steroid functions. Like most of biological molecules, AR functional activities are modulated by post-translational modifications. This review is focused on the reported activities and significance of AR phosphorylation, with particular emphasis on proline-directed serine/threonine phosphorylation that occurs predominantly on the receptor. The marked enrichment of AR phosphorylation in the most diverse N-terminal domain suggests that targeting AR phosphorylation can be synergistic to antagonizing the C-terminal domain by clinical antiandrogens.
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Affiliation(s)
- Yanfei Gao
- Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School 330 Brookline, MA 02115, USA
| | - Shaoyong Chen
- Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School 330 Brookline, MA 02115, USA
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84
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Puzianowska-Kuznicka M, Pawlik-Pachucka E, Owczarz M, Budzińska M, Polosak J. Small-molecule hormones: molecular mechanisms of action. Int J Endocrinol 2013; 2013:601246. [PMID: 23533406 PMCID: PMC3603355 DOI: 10.1155/2013/601246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 12/30/2012] [Accepted: 01/17/2013] [Indexed: 01/01/2023] Open
Abstract
Small-molecule hormones play crucial roles in the development and in the maintenance of an adult mammalian organism. On the molecular level, they regulate a plethora of biological pathways. Part of their actions depends on their transcription-regulating properties, exerted by highly specific nuclear receptors which are hormone-dependent transcription factors. Nuclear hormone receptors interact with coactivators, corepressors, basal transcription factors, and other transcription factors in order to modulate the activity of target genes in a manner that is dependent on tissue, age and developmental and pathophysiological states. The biological effect of this mechanism becomes apparent not earlier than 30-60 minutes after hormonal stimulus. In addition, small-molecule hormones modify the function of the cell by a number of nongenomic mechanisms, involving interaction with proteins localized in the plasma membrane, in the cytoplasm, as well as with proteins localized in other cellular membranes and in nonnuclear cellular compartments. The identity of such proteins is still under investigation; however, it seems that extranuclear fractions of nuclear hormone receptors commonly serve this function. A direct interaction of small-molecule hormones with membrane phospholipids and with mRNA is also postulated. In these mechanisms, the reaction to hormonal stimulus appears within seconds or minutes.
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Affiliation(s)
- Monika Puzianowska-Kuznicka
- Department of Human Epigenetics, Mossakowski Medical Research Centre, 5 Pawinskiego Street, 02-106 Warsaw, Poland
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
- *Monika Puzianowska-Kuznicka:
| | - Eliza Pawlik-Pachucka
- Department of Human Epigenetics, Mossakowski Medical Research Centre, 5 Pawinskiego Street, 02-106 Warsaw, Poland
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
| | - Magdalena Owczarz
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
| | - Monika Budzińska
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
| | - Jacek Polosak
- Department of Human Epigenetics, Mossakowski Medical Research Centre, 5 Pawinskiego Street, 02-106 Warsaw, Poland
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85
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Androgen receptor phosphorylation at serine 515 by Cdk1 predicts biochemical relapse in prostate cancer patients. Br J Cancer 2012; 108:139-48. [PMID: 23321516 PMCID: PMC3553508 DOI: 10.1038/bjc.2012.480] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Background: Prostate cancer cell growth is dependent upon androgen receptor (AR) activation, which is regulated by specific kinases. The aim of the current study is to establish if AR phosphorylation by Cdk1 or ERK1/2 is of prognostic significance. Methods: Scansite 2.0 was utilised to predict which AR sites are phosphorylated by Cdk1 and ERK1/2. Immunohistochemistry for these sites was then performed on 90 hormone-naive prostate cancer specimens. The interaction between Cdk1/ERK1/2 and AR phosphorylation was investigated in vitro using LNCaP cells. Results: Phosphorylation of AR at serine 515 (pARS515) and PSA at diagnosis were independently associated with decreased time to biochemical relapse. Cdk1 and pCdk1161, but not ERK1/2, correlated with pARS515. High expression of pARS515 in patients with a PSA at diagnosis of ⩽20 ng ml−1 was associated with shorter time to biochemical relapse (P=0.019). This translated into a reduction in disease-specific survival (10-year survival, 38.1% vs 100%, P<0.001). In vitro studies demonstrated that treatment with Roscovitine (a Cdk inhibitor) caused a reduction in pCdk1161 expression, pARS515expression and cellular proliferation. Conclusion: In prostate cancer patients with PSA at diagnosis of ⩽20 ng ml−1, phosphorylation of AR at serine 515 by Cdk1 may be an independent prognostic marker.
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Abstract
The androgen receptor (AR) is a key molecule in prostate cancer and Kennedy's disease. Understanding the regulatory mechanisms of this steroid receptor is important in the development of potential therapies for these diseases. One layer of AR regulation is provided by post-translational modifications including phosphorylation, acetylation, sumoylation, ubiquitination and methylation. While these modifications have mostly been studied as individual events, it is becoming clear that these modifications can functionally interact with each other in a signalling pathway. In this review, the effects of all modifications are described with a focus on interplay between them and the functional consequences for the AR.
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Affiliation(s)
- Kelly Coffey
- Solid Tumour Target Discovery Group, The Medical School, Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Framlington Place, Newcastle upon Tyne, Tyne and Wear, UK
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87
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Phosphorylation of the androgen receptor by PIM1 in hormone refractory prostate cancer. Oncogene 2012; 32:3992-4000. [PMID: 22986532 PMCID: PMC3527659 DOI: 10.1038/onc.2012.412] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 07/13/2012] [Accepted: 07/25/2012] [Indexed: 12/11/2022]
Abstract
Integration of cellular signaling pathways with androgen receptor (AR) signaling can be achieved through phosphorylation of AR by cellular kinases. However, the kinases responsible for phosphorylating the androgen receptor at numerous sites and the functional consequences of AR phosphorylation are only partially understood. Bioinformatic analysis revealed AR serine 213 (S213) as a putative substrate for PIM1, a kinase overexpressed in prostate cancer. Therefore, phosphorylation of AR serine 213 by PIM1 was examined using a phosphorylation site-specific antibody. Wild type PIM1, but not catalytically inactive PIM1, specifically phosphorylated AR but not an AR serine to alanine mutant (S213A). In vitro kinase assays confirmed that PIM1 can phosphorylate AR S213 in a ligand independent manner and cell type specific phosphorylation was observed in prostate cancer cell lines. Upon PIM1 overexpression AR phosphorylation was observed in the absence of hormone and was further increased in the presence of hormone in LNCaP, LNCaP-abl, and VCaP cells. Moreover, phosphorylation of AR was reduced in the presence of PIM kinase inhibitors. An examination of AR mediated transcription showed that reporter gene activity was reduced in the presence of PIM1 and wild type AR, but not S213A mutant AR. Androgen mediated transcription of endogenous PSA, Nkx3.1, and IGFBP5 was also decreased in the presence of PIM1 whereas IL6, cyclin A1, and caveolin 2 were increased. Immunohistochemical analysis of prostate cancer tissue microarrays showed significant P-AR S213 expression that was associated with hormone refractory prostate cancers, likely identifying cells with catalytically active PIM1. In addition, prostate cancers expressing a high level of P-AR S213 were twice as likely to be from biochemically recurrent cancers. Thus, AR phosphorylation by PIM1 at S213 impacts gene transcription and is highly prevalent in aggressive prostate cancer.
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88
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Sampson N, Ruiz C, Zenzmaier C, Bubendorf L, Berger P. PAGE4 positivity is associated with attenuated AR signaling and predicts patient survival in hormone-naive prostate cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:1443-54. [PMID: 22885105 DOI: 10.1016/j.ajpath.2012.06.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 05/30/2012] [Accepted: 06/26/2012] [Indexed: 11/27/2022]
Abstract
Aberrant activation of the androgen receptor (AR) plays a key role during prostate cancer (PCa) development and progression to castration-resistant prostate cancer (CR-PCa) after androgen deprivation therapy, the mainstay systemic treatment for PCa. New strategies to abrogate AR activity and biomarkers that predict aggressive tumor behavior are essential for improved therapeutic intervention. PCa tissue microarrays herein reveal that prostate-associated gene 4 (PAGE4), an X-linked cancer/testis antigen, is highly up-regulated in the epithelium of preneoplastic lesions compared with benign epithelium, but subsequently decreases with tumor progression. We show that AR signaling is attenuated in PAGE4-expressing cells both in vitro and in vivo, most likely via impaired androgen-induced AR nuclear translocation and subsequently reduced AR protein stabilization and phosphorylation at serines 81 and 213. Consistently, epithelial PAGE4 protein levels inversely correlated with AR activation status in hormone-naive and CR-PCa clinical specimens. Moreover, PAGE4 impaired the development of CR-PCa xenografts, and strong PAGE4 immunoreactivity independently predicted favorable patient survival in hormone-naive PCa. Collectively, these data suggest that dysregulation of epithelial PAGE4 modulates AR signaling, thereby promoting progression to advanced lethal PCa and highlight the potential value of PAGE4 as a prognostic and therapeutic target.
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Affiliation(s)
- Natalie Sampson
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck, Austria.
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