1
|
Fontana F, Limonta P. Dissecting the Hormonal Signaling Landscape in Castration-Resistant Prostate Cancer. Cells 2021; 10:1133. [PMID: 34067217 PMCID: PMC8151003 DOI: 10.3390/cells10051133] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023] Open
Abstract
Understanding the molecular mechanisms underlying prostate cancer (PCa) progression towards its most aggressive, castration-resistant (CRPC) stage is urgently needed to improve the therapeutic options for this almost incurable pathology. Interestingly, CRPC is known to be characterized by a peculiar hormonal landscape. It is now well established that the androgen/androgen receptor (AR) axis is still active in CRPC cells. The persistent activity of this axis in PCa progression has been shown to be related to different mechanisms, such as intratumoral androgen synthesis, AR amplification and mutations, AR mRNA alternative splicing, increased expression/activity of AR-related transcription factors and coregulators. The hypothalamic gonadotropin-releasing hormone (GnRH), by binding to its specific receptors (GnRH-Rs) at the pituitary level, plays a pivotal role in the regulation of the reproductive functions. GnRH and GnRH-R are also expressed in different types of tumors, including PCa. Specifically, it has been demonstrated that, in CRPC cells, the activation of GnRH-Rs is associated with a significant antiproliferative/proapoptotic, antimetastatic and antiangiogenic activity. This antitumor activity is mainly mediated by the GnRH-R-associated Gαi/cAMP signaling pathway. In this review, we dissect the molecular mechanisms underlying the role of the androgen/AR and GnRH/GnRH-R axes in CRPC progression and the possible therapeutic implications.
Collapse
Affiliation(s)
| | - Patrizia Limonta
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy;
| |
Collapse
|
2
|
A Survey of Feature Set Reduction Approaches for Predictive Analytics Models in the Connected Manufacturing Enterprise. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9050843] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The broad context of this literature review is the connected manufacturing enterprise, characterized by a data environment such that the size, structure and variety of information strain the capability of traditional software and database tools to effectively capture, store, manage and analyze it. This paper surveys and discusses representative examples of existing research into approaches for feature set reduction in the big data environment, focusing on three contexts: general industrial applications; specific industrial applications such as fault detection or fault prediction; and data reduction. The conclusion from this review is that there is room for research into frameworks or approaches to feature filtration and prioritization, specifically with respect to providing quantitative or qualitative information about the individual features in the dataset that can be used to rank features against each other. A byproduct of this gap is a tendency for analysts not to holistically generalize results beyond the specific problem of interest, and, related, for manufacturers to possess only limited knowledge of the relative value of smart manufacturing data collected.
Collapse
|
3
|
Varamini P, Mansfeld FM, Giddam AK, Steyn F, Toth I. New gonadotropin-releasing hormone glycolipids with direct antiproliferative activity and gonadotropin-releasing potency. Int J Pharm 2017; 521:327-336. [PMID: 28232269 DOI: 10.1016/j.ijpharm.2017.02.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/10/2017] [Accepted: 02/19/2017] [Indexed: 11/19/2022]
Affiliation(s)
- Pegah Varamini
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia.
| | - Friederike M Mansfeld
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Ashwini Kumar Giddam
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Frederik Steyn
- The University of Queensland Centre for Clinical Research and the School of Biomedical Sciences, Brisbane, Australia
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia; School of Pharmacy, The University of Queensland, Brisbane, Australia; Institute for Molecular Biosciences, The University of Queensland, Brisbane, Australia
| |
Collapse
|
4
|
Chang C, Varamini P, Giddam AK, Mansfeld FM, D'Occhio MJ, Toth I. Investigation of Structure-Activity Relationships of Synthetic Anti-Gonadotropin Releasing Hormone Vaccine Candidates. ChemMedChem 2015; 10:901-10. [DOI: 10.1002/cmdc.201500036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 11/05/2022]
|
5
|
Limonta P, Manea M. Gonadotropin-releasing hormone receptors as molecular therapeutic targets in prostate cancer: Current options and emerging strategies. Cancer Treat Rev 2013; 39:647-63. [DOI: 10.1016/j.ctrv.2012.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/03/2012] [Indexed: 12/28/2022]
|
6
|
Sviridonov L, Dobkin-Bekman M, Shterntal B, Przedecki F, Formishell L, Kravchook S, Rahamim-Ben Navi L, Bar-Lev TH, Kazanietz MG, Yao Z, Seger R, Naor Z. Differential signaling of the GnRH receptor in pituitary gonadotrope cell lines and prostate cancer cell lines. Mol Cell Endocrinol 2013; 369:107-18. [PMID: 23380421 PMCID: PMC4100609 DOI: 10.1016/j.mce.2013.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/09/2013] [Accepted: 01/14/2013] [Indexed: 10/27/2022]
Abstract
The GnRH receptor (GnRHR) mediates the pituitary functions of GnRH, as well as its anti-proliferative effects in sex hormone-dependent cancer cells. Here we compare the signaling of GnRHR in pituitary gonadotrope cell lines vs. prostate cancer cell lines. We first noticed that the expression level of PKCα, PKCβII and PKCε is much higher in αT3-1 and LβT2 gonadotrope cell lines vs. LNCaP and DU-145 cell lines, while the opposite is seen for PKCδ. Activation of PKCα, PKCβII and PKCε by GnRH is relatively transient in αT3-1 and LβT2 gonadotrope cell lines and more prolonged in LNCaP and DU-145 cell lines. On the otherhand, the activation and re-distribution of the above PKCs by PMA was similar for both gonadotrope cell lines and prostate cancer cell lines. Activation of ERK1/2 by GnRH and PMA was robust in the gonadotrope cell lines, with a smaller effect observed in the prostate cancer cell lines. The Ca(2+) ionophore A23187 stimulated ERK1/2 in gonadotrope cell lines but not in prostate cancer cell lines. GnRH, PMA and A23187 stimulated JNK activity in gonadotrope cell lines, with a more sustained effect in prostate cancer cell lines. Sustained activation of p38 was observed for PMA and A23187 in Du-145 cells, while p38 activation by GnRH, PMA and A23187 in LβT2 cells was transient. Thus, differential expression and re-distribution of PKCs by GnRH and the transient vs. the more sustained nature of the activation of the PKC-MAPK cascade by GnRH in gonadotrope cell lines vs. prostate cancer cell lines respectively, may provide the mechanistic basis for the cell context-dependent differential biological responses observed in GnRH interaction with pituitary gonadotropes vs. prostate cancer cells.
Collapse
Affiliation(s)
- Ludmila Sviridonov
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Morgan K, Stavrou E, Leighton SP, Miller N, Sellar R, Millar RP. Elevated GnRH receptor expression plus GnRH agonist treatment inhibits the growth of a subset of papillomavirus 18-immortalized human prostate cells. Prostate 2011; 71:915-28. [PMID: 21541969 DOI: 10.1002/pros.21308] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 10/18/2010] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND AIMS Human metastatic prostate cancer cell growth can be inhibited by GnRH analogs but effects on virus-immortalized prostate cells have not been investigated. METHODS Virus-immortalized prostate cells were stably transfected with rat GnRH receptor cDNA and levels of GnRH binding were correlated with GnRH effects on signaling, cell cycle, growth, exosome production, and apoptosis. RESULTS High levels of cell surface GnRH receptor occurred in transfected papillomavirus-immortalized WPE-1-NB26 epithelial cells but not in non-tumourigenic RWPE-1, myoepithelial WPMY-1 cells, or SV40-immortalized PNT1A. Endogenous cell surface GnRH receptor was undetectable in non-transfected cells or cancer cell lines LNCaP, PC3, and DU145. GnRH receptor levels correlated with induction of inositol phosphates, elevation of intracellular Ca(2+) , cytoskeletal actin reorganization, modulation of ERK activation and cell growth-inhibition with GnRH agonists. Hoechst 33342 DNA staining-cell sorting indicated accumulation of cells in G2 following agonist treatment. Release of exosomes from transfected WPE-1-NB26 was unaffected by agonists, unlike induction observed in HEK293([SCL60]) cells. Increased PARP cleavage and apoptotic body production were undetectable during growth-inhibition in WPE-1-NB26 cells, contrasting with HEK293([SCL60]) . EGF receptor activation inhibited GnRH-induced ERK activation in WPE-1-NB26 but growth-inhibition was not rescued by EGF or PKC inhibitor Ro320432. Growth of cells expressing low levels of GnRH receptor was not affected by agonists. CONCLUSIONS Engineered high-level GnRH receptor activation inhibits growth of a subset of papillomavirus-immortalized prostate cells. Elucidating mechanisms leading to clone-specific differences in cell surface GnRH receptor levels is a valuable next step in developing strategies to exploit prostate cell anti-proliferation using GnRH agonists.
Collapse
Affiliation(s)
- Kevin Morgan
- Medical Research Council Human Reproductive Sciences Unit, The Queen's Medical Research Institute, Little France Crescent, Edinburgh, UK.
| | | | | | | | | | | |
Collapse
|
8
|
Morgan K, Stewart AJ, Miller N, Mullen P, Muir M, Dodds M, Medda F, Harrison D, Langdon S, Millar RP. Gonadotropin-releasing hormone receptor levels and cell context affect tumor cell responses to agonist in vitro and in vivo. Cancer Res 2008; 68:6331-40. [PMID: 18676858 DOI: 10.1158/0008-5472.can-08-0197] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Activation of gonadotropin-releasing hormone (GnRH) receptors inhibits proliferation of transformed cells derived from reproductive tissues and in transfected cell lines. Hence, GnRH receptors represent a therapeutic target for direct action of GnRH analogues on certain proliferating cells. However, more cell biological data are required to develop this particular application of GnRH analogues. Therefore, we compared the effects of GnRH receptor activation in transfected HEK293 cells (HEK293([SCL60])) with transfected human ovarian cancer cell lines SKOV3 and EFO21, human hepatoblastoma HepG2 cells, and rat neuroblastoma B35 cells. Marked differences in receptor levels, magnitude of inositol phosphate generation, and dynamics of inositol phosphate turnover occurred in the different cells. Activation of GnRH receptors, expressed at high or moderate levels, inhibited the growth of HEK293([SCL60]) and B35 cells, respectively. Western blotting detected markers of apoptosis [cleaved poly(ADP-ribose) polymerase, caspase-9] in HEK293([SCL60]) and B35 following treatment with 100 nmol/L d-Trp(6)-GnRH-I. Cell growth inhibition was partially or completely rescued with inhibitor Q-VD-OPh or Ro32-0432. Low levels of GnRH receptor expression in transfected SKOV3, EFO21, or HepG2 activated intracellular signaling but did not induce apoptosis or significantly affect cell proliferation. Tumor xenografts prepared from HEK293([SCL60]) regressed during treatment with d-Trp(6)-GnRH-I and growth of xenografts derived from transfected B35 was slowed. SKOV3 xenografts were not growth inhibited. Therefore, differences in levels of GnRH receptor and signaling differentially affect the apoptotic machinery within cell lines and contribute to the cell type-specific effects of GnRH on growth. Further studies should exploit the growth-inhibitory potential of GnRH receptor activation in abnormal cells in diseased human tissues.
Collapse
Affiliation(s)
- Kevin Morgan
- Medical Research Council Human Reproductive Sciences Unit, Edinburgh Cancer Research Centre, Edinburgh, United Kingdom.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Finch AR, Sedgley KR, Caunt CJ, McArdle CA. Plasma membrane expression of GnRH receptors: regulation by antagonists in breast, prostate, and gonadotrope cell lines. J Endocrinol 2008; 196:353-67. [PMID: 18252959 PMCID: PMC2229628 DOI: 10.1677/joe-07-0471] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In heterologous expression systems, human GnRH receptors (hGnRHRs) are poorly expressed at the cell surface and this may reflect inefficient exit from the endoplasmic reticulum. Here, we have defined the proportion of GnRHRs at the cell surface using a novel assay based on adenoviral transduction with epitope-tagged GnRHRs followed by staining and semi-automated imaging. We find that in MCF7 (breast cancer) cells, the proportional cell surface expression (PCSE) of hGnRHRs is remarkably low (<1%), when compared with Xenopus laevis (X) GnRHRs ( approximately 40%). This distinction is retained at comparable whole cell expression levels, and the hGnRHR PCSE is increased by addition of the XGnRHR C-tail (h.XGnRHR) or by a membrane-permeant pharmacological chaperone (IN3). The IN3 effect is concentration- and time-dependent and IN3 also enhances the hGnRHR-mediated (but not h.XGnRHR- or mouse GnRHR-mediated) stimulation of [(3)H]inositol phosphate accumulation and the hGnRHR-mediated reduction in cell number. We also find that the PCSE for hGnRHRs and h.XGnRHRs is low and is greatly increased by IN3 in two hormone-dependent cancer lines, but is higher and less sensitive to IN3 in a gonadotrope line. Finally, we show that the effect of IN3 on hGnRHR PCSE is not mimicked or blocked by two peptide antagonists although they do increase the PCSE for h.XGnRHRs, revealing that an antagonist-occupied cell surface GnRHR conformation can differ from that of the unoccupied receptor. The low PCSE of hGnRHRs and this novel peptide antagonist effect may be important for understanding GnRHR function in extrapituitary sites.
Collapse
|
10
|
Castellón E, Clementi M, Hitschfeld C, Sánchez C, Benítez D, Sáenz L, Contreras H, Huidobro C. Effect of leuprolide and cetrorelix on cell growth, apoptosis, and GnRH receptor expression in primary cell cultures from human prostate carcinoma. Cancer Invest 2006; 24:261-8. [PMID: 16809153 DOI: 10.1080/07357900600629591] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Contradictory data have been reported regarding the effect of GnRH agonists and antagonists on cell growth and survival, using prostate cancer-derived cell lines expressing either endogenous or exogenous GnRH receptors. We addressed the issue studying the effect of leuprolide (agonist) and cetrorelix (antagonist) on cell growth, apoptosis and GnRH receptor expression using a primary cell coculture system. Also, binding characteristics of prostate GnRH receptor in this culture system are described. Epithelial and stromal cells were obtained from prostate adenocarcinoma samples and cocultured in a bicameral system. Expression of GnRH receptors was evaluated by semiquantitative RT-PCR (transcript level) and Western blot (protein level). Cell growth was estimated by MTT method and apoptosis by DNA fragmentation using COMET assay. Saturation and competition binding studies were carried out using 125I-GnRH as radioligand. GnRH receptors from cell cultures of prostate cancer exhibited a single class of binding sites with a Kd of 1.11 +/- 0.28 nM and a Bmax of 2.81 +/- 0.37 pmol/mg of membrane protein for GnRH. Leuprolide and cetrorelix showed no effect on GnRH receptor expression. Both analogues showed a significant reduction in cell growth rate and an increase in DNA-fragmented cell number. These effects were dependent on the analogue concentrations (from 5-20 ng/mL). Considering that the culture system used in this work represents more closely the in vivo conditions of tumor cells than metastatic derived cell lines, we conclude that GnRH analogues have a significant inhibitory effect on cell viability of cells expressing GnRH receptors. In addition, GnRH receptors expressed in tumor prostatic cells seem not discriminate between agonist and antagonist, both analogues activating these receptors. Also, leuprolide and cetrorelix treatments did not influence GnRH receptor expression in our culture system. These differences with pituitary receptors may be explained by differences in affinity, transduction mechanism and molecular context in prostatic tissue.
Collapse
Affiliation(s)
- Enrique Castellón
- Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Maudsley S, Davidson L, Pawson AJ, Freestone SH, López de Maturana R, Thomson AA, Millar RP. Gonadotropin-releasing hormone functionally antagonizes testosterone activation of the human androgen receptor in prostate cells through focal adhesion complexes involving Hic-5. Neuroendocrinology 2006; 84:285-300. [PMID: 17202804 DOI: 10.1159/000098402] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 10/05/2006] [Indexed: 11/19/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) analogs constitute the most widely employed medical treatment for prostatic cancer. The predominant mechanism of action is presumed to be via the inhibition of gonadotropins and resultant decrease in androgen. However, GnRH analogs have also been shown to directly inhibit prostate cancer cells both in vitro and in vivo through antiproliferative cell cycle arrest and stimulation of apoptosis. Since the GnRH receptor has been shown to affect sex steroid hormone receptor function, we considered that part of GnRH analog actions on prostate cells may be mediated through modulation of the human androgen receptor. Using a model HEK293 cell line expressing the GnRH receptor, we demonstrated a novel signalling pathway of the GnRH receptor that induces nuclear translocation of the androgen receptor that renders it transcriptionally inactive. This mechanism involves the calcium-dependent tyrosine kinase Pyk2, the non-receptor tyrosine kinase c-Src and the focal adhesion protein/steroid receptor co-factor, Hic-5. In this setting there is a GnRH-induced association and nuclear translocation of the androgen receptor with Hic-5. GnRH-induced Pyk2 activation opposed the association of Hic-5 with androgen receptor as overexpression of a dominant negative Pyk2 enhanced the GnRH-induced nuclear translocation of a green fluorescent protein-tagged human androgen receptor. GnRH-induced c-Src activation resulted in the phosphorylation of expressed Hic-5 and promoted its association with the human androgen receptor. In contrast to testosterone, GnRH-induced nuclear translocation did not transcriptionally activate the androgen receptor. We then demonstrated that GnRH can also stimulate androgen receptor mobilization in human prostate PC3, BPH-1 and LNCaP cells, and in cultured rat ventral prostate cells through the same mechanism. To determine if GnRH could antagonize androgen effects in normal tissue, we examined the effect of GnRH on rat ventral prostate organ cultures and demonstrated that GnRH can functionally antagonize the actions of testosterone on prostate cell proliferation and tissue growth. This antagonism of testosterone action by GnRH may underlie in part the capacity of GnRH receptor activation to inhibit prostate tumor growth.
Collapse
Affiliation(s)
- Stuart Maudsley
- Medical Research Council Human Reproductive Sciences Unit, The Queen's Medical Research Institute, and Ardana Bioscience, Edinburgh, UK
| | | | | | | | | | | | | |
Collapse
|
12
|
Wagner M, Garzotto M, Lemmon D, Eilers KM, Beer TM. Prostate-specific antigen decline after gonadotropin-releasing hormone antagonist withdrawal in androgen-independent prostate cancer. Urology 2005; 65:799. [PMID: 15833548 DOI: 10.1016/j.urology.2004.10.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Revised: 10/01/2004] [Accepted: 10/26/2004] [Indexed: 11/23/2022]
Abstract
A 66-year-old man with androgen-independent prostate cancer was treated with abarelix, a gonadotropin-releasing hormone antagonist, for 20 weeks in an experimental protocol. He did not respond to therapy, but his serum prostate-specific antigen level dropped from 15.8 ng/mL to a confirmed 0.8 ng/mL after abarelix was stopped. His prostate-specific antigen level did not return to greater than 15.8 ng/mL for 14 months. This is the first report of a withdrawal response after therapy with a gonadotropin-releasing hormone antagonist, a new class of agents for prostate cancer. Additional observations are needed to determine whether this is an isolated case or a harbinger of a more common phenomenon.
Collapse
Affiliation(s)
- Matthew Wagner
- Division of Urology, Oregon Health & Science University, Portland, Oregon 97239, USA
| | | | | | | | | |
Collapse
|
13
|
Sánchez C, Clementi M, Benitez D, Contreras H, Huidobro C, Castellón E. Effect of GnRH analogs on the expression of TrkA and p75 neurotrophin receptors in primary cell cultures from human prostate adenocarcinoma. Prostate 2005; 65:195-202. [PMID: 15948150 DOI: 10.1002/pros.20281] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND GnRH analogs have antiproliferative and/or apoptotic effects on prostate cancer cells. Also, neurotrophin receptors TrkA and p75 have been reported in normal prostate suggesting a role in the gland growth control. In prostate cancer, TrkA receptors seem to be overexpressed and p75 receptors show a decreased expression. These changes in neurotrophin receptors may be related with unbalanced growth in malignant cells. In the present study we investigate the effects of GnRH analogs (leuprolide and cetrorelix) on the expression of TrkA and p75 neurotrophin receptors in primary cultures of human prostate cancer cells. METHODS Tissue was obtained from radical prostatectomies due to prostate adenocarcinoma. Cells were isolated after sequential enzyme digestion and cultured in defined media. Nerve growth factor (NGF) receptors in untreated cultures were estimated by immunofluorescence. Cultures were treated with leuprolide (agonist) or cetrorelix (antagonist) and expression of TrkA and p75 receptors were evaluated by semi quantitative RT-PCR (polymerase chain reaction) and western blot. Cell proliferation was estimated by MTT method and apoptosis through COMET assay. RESULTS Both leuprolide and cetrorelix induced a significant increase in p75 receptor gene and protein expression at a concentration that induce apoptosis and decrease proliferation. TrkA receptors showed no changes in presence of GnRH analogs. CONCLUSIONS GnRH analogs, leuprolide, and cetrorelix, change the ratio between neurotrophin receptors TrkA and p75 by increasing gene and protein expression of p75 receptor. Considering that TrkA receptor is related with proliferation and p75 with apoptosis, we suggest that our findings may explain, in part, the effect of GnRH analogs on prostate cancer growth.
Collapse
Affiliation(s)
- Catherine Sánchez
- Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | | | | | | | | | | |
Collapse
|
14
|
Hapgood JP, Sadie H, van Biljon W, Ronacher K. Regulation of expression of mammalian gonadotrophin-releasing hormone receptor genes. J Neuroendocrinol 2005; 17:619-38. [PMID: 16159375 DOI: 10.1111/j.1365-2826.2005.01353.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH), acting via its cognate GnRH receptor (GnRHR), is the primary regulator of mammalian reproductive function, and hence GnRH analogues are extensively used in the treatment of hormone-dependent diseases, as well as for assisted reproductive techniques. In addition to its established endocrine role in gonadotrophin regulation in the pituitary, evidence is rapidly accumulating to support the expression and functional roles for two forms of GnRHR (GnRHR I and GnRHR II) in multiple and diverse extra-pituitary mammalian tissues and cells. These findings, together with findings indicating that mutations of the GnRHR are linked to the disease hypogonadotrophic hypogonadism and that GnRHRs play a direct role in neuronal migration and reproductive cancers, have presented new therapeutic targets and intensified research into the structure, function and mechanisms of regulation of expression of GnRHR genes. The present review focuses on the current knowledge on tissue-specific and hormonal regulation of transcription of mammalian GnRH receptor genes. Emerging insights, such as the discovery of diverse regulatory mechanisms in pituitary and extra-pituitary cell types, nonclassical mechanisms of steroid regulation, the use of composite elements for cell-specific expression, the increasing profile of hormones involved in regulation, the complexity of kinase pathways that target the GnRHR I gene, as well as species-differences, are highlighted. Although further research is necessary to understand the mechanisms of regulation of expression of GnRHR I and GnRHR II genes, the GnRHR is emerging as a potential target gene for facilitating cross-talk between neuroendocrine, immune and stress-response systems in multiple tissues via autocrine, paracrine and endocrine signalling.
Collapse
Affiliation(s)
- J P Hapgood
- Department of Biochemistry, University of Stellenbosch, Matieland, South Africa.
| | | | | | | |
Collapse
|
15
|
Nagy A, Schally AV. Targeting of cytotoxic luteinizing hormone-releasing hormone analogs to breast, ovarian, endometrial, and prostate cancers. Biol Reprod 2005; 73:851-9. [PMID: 16033997 DOI: 10.1095/biolreprod.105.043489] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Targeted chemotherapy is a modern approach aimed at increasing the efficacy of systemic chemotherapy and reducing its side effects. The peptide receptors expressed primarily on cancerous cells can serve as targets for a selective destruction of malignant tumors. Binding sites for LHRH (now known in genome and microarray databases as GNRH1), were found on 52% of human breast cancers, about 80% of human ovarian and endometrial cancers, and 86% of human prostatic carcinoma specimens. Because LHRH receptors are not expressed on most normal tissues, they represent a specific target for cancer chemotherapy with antineoplastic agents linked to an LHRH vector molecule. To test the efficacy of targeted chemotherapy based on LHRH analogs, we recently developed a cytotoxic analog of LHRH, designated AN-152, which consists of [D-Lys6]LHRH covalently linked to one of the most widely used chemotherapeutic agents, doxorubicin (DOX). In addition, we designed and synthesized a highly active derivative of DOX, 2-pyrrolino-DOX (AN-201), which is 500-1000 times more potent than DOX in vitro. AN-201 is active against tumors resistant to DOX, and noncardiotoxic. As in the case of DOX, AN-201 was coupled to carrier peptide [D-Lys6]LHRH to form a superactive targeted cytotoxic LHRH analog, AN-207. Both AN-152 and AN-207 can effectively inhibit the growth of LHRH receptor-positive human breast, ovarian, endometrial, and prostate cancers xenografted into nude mice. DOX-containing cytotoxic LHRH analog AN-152 is scheduled for clinical phase I/IIa trials in patients with advanced ovarian and breast cancers in 2005.
Collapse
Affiliation(s)
- Attila Nagy
- Section of Experimental Medicine, Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | | |
Collapse
|
16
|
Gnanapragasam VJ, Darby S, Khan MM, Lock WG, Robson CN, Leung HY. Evidence that prostate gonadotropin-releasing hormone receptors mediate an anti-tumourigenic response to analogue therapy in hormone refractory prostate cancer. J Pathol 2005; 206:205-13. [PMID: 15818594 DOI: 10.1002/path.1767] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gonadotropin-releasing hormone analogue (GnRHa) therapy is an established method of androgen withdrawal in the treatment of prostate cancer. The present study investigated if the expression of prostate GnRH receptors (GnRHRs) might influence the response to GnRHa. GnRHR protein expression was first studied in a panel of prostate cancer cell lines. In androgen-dependent cells, GnRHR expression was unchanged following acute or chronic androgen withdrawal. In these cells, GnRHa significantly inhibited androgen-induced cell proliferation (p = 0.01). In contrast, GnRHa was unable to further suppress basal levels of cell proliferation induced by androgen withdrawal. In androgen-independent prostate cancer cells, variable levels of GnRHR expression were observed. In these cells, GnRHa treatment blocked cell proliferation (p = 0.001) and invasion (up to 70%) induced by fibroblast growth factor stimulation. Crucially, this effect was only evident in cells that expressed high levels of the GnRHR. GnRHa treatment also significantly inhibited the ability of these cells to recover from a cytotoxic insult (50% inhibition). The clinical significance of prostate GnRHR was tested by immunohistochemistry in a preliminary cohort of patients treated with GnRHa or surgical castration. There was no association between GnRHR expression and pathological grade, clinical stage, time to PSA nadir (p = 0.82) (n = 35) or progression to hormone refractory disease (p = 0.22) (n = 21), irrespective of the treatment method. GnRHa therapy in the presence of high GnRHR expression however, was found to be associated with longer disease-specific survival (mean survival 85 months, p = 0.002). In contrast, high GnRHR expression was not associated with survival among surgically castrated patients (mean survival 50 months, p = 0.7). Taken together, these data support the notion of a functional interaction between GnRHa and the GnRHR, which results in an anti-tumourigenic effect on prostate cancer cells. Findings from this report have direct implications for the use of GnRHR as a novel therapeutic target in hormone refractory prostate cancer.
Collapse
Affiliation(s)
- V J Gnanapragasam
- Urology Research Group, Northern Institute for Cancer Research, Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
| | | | | | | | | | | |
Collapse
|
17
|
Kraus S, Levy G, Hanoch T, Naor Z, Seger R. Gonadotropin-releasing hormone induces apoptosis of prostate cancer cells: role of c-Jun NH2-terminal kinase, protein kinase B, and extracellular signal-regulated kinase pathways. Cancer Res 2004; 64:5736-44. [PMID: 15313914 DOI: 10.1158/0008-5472.can-04-1156] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A standard therapy used today for prostate cancer is androgen ablation by gonadotropin-releasing hormone analogs (GnRH-a). Although most patients respond to androgen ablation as an initial systemic therapy, nearly all cases will develop androgen resistance, the management of which is still a major challenge. Here, we report that GnRH-a can directly induce apoptosis of the androgen-independent prostate cancer-derived DU145 and PC3 cell lines. Using specific inhibitors, we found that the apoptotic effect of GnRH-a is mediated by c-Jun NH2-terminal kinase (JNK) and inhibited by the phosphatidylinositol 3'-kinase (PI3K)-protein kinase B (PKB) pathway. Indeed, in DU145 cells, GnRH-a activates the JNK cascade in a c-Src- and MLK3-dependent manner but does not involve protein kinase C and epidermal growth factor receptor. Concomitantly, GnRH-a reduces the activity of the PI3K-PKB pathway, which results in the dephosphorylation of PKB mainly in the nucleus. The reduction of PKB activity releases PKB-induced inhibition of MLK3 and thus further stimulates JNK activity and accelerates the apoptotic effect of GnRH-a. Interestingly, extracellular signal-regulated kinase is also activated by GnRH-a, and this occurs via a pathway that involves matrix metalloproteinases and epidermal growth factor receptor, but its activation does not affect JNK activation and the GnRH-a-induced apoptosis. Our results support a potential use of GnRH-a for the treatment of advanced prostate cancer and suggest that the outcome of this treatment can be amplified by using PI3K-PKB inhibitors.
Collapse
Affiliation(s)
- Sarah Kraus
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | | |
Collapse
|
18
|
Beer TM, Garzotto M, Eilers KM, Lemmon D, Wersinger EM. Targeting FSH in androgen-independent prostate cancer: abarelix for prostate cancer progressing after orchiectomy. Urology 2004; 63:342-7. [PMID: 14972486 DOI: 10.1016/j.urology.2003.09.045] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2003] [Accepted: 09/12/2003] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To determine the efficacy of the gonadotropin-releasing hormone antagonist abarelix in patients with androgen-independent prostate cancer progressing after orchiectomy and to measure its effect on serum follicle-stimulating hormone (FSH). METHODS Sixteen patients with prostate cancer progressing after orchiectomy received abarelix-depot 100 mg by intramuscular injection on days 1, 15, and 29 and then every 28 days for up to 24 weeks (52 weeks in patients who met the criteria for a prostate-specific antigen [PSA] response after 24 weeks). PSA response was the primary endpoint and was defined as a 50% reduction confirmed 4 weeks later. The time to progression and effect of therapy on serum FSH were secondary endpoints. RESULTS No patient met the criteria for a PSA response. Five patients (31%, 95% confidence interval 11% to 58%) experienced confirmed reductions in the PSA level ranging from 9.3% to 31.8%. At the end of the six cycles of therapy, 6 patients remained stable without PSA progression or other signs of disease progression. The median time to progression was 12 weeks (95% confidence interval 6 to 18). The mean serum FSH concentration declined after 4 weeks of study treatment by nearly 90% from a baseline of 45.1 IU/L (95% confidence interval 34.0 to 56.2) and remained suppressed throughout the observation period. Treatment was well tolerated, with one grade 3 allergic reaction. CONCLUSIONS Treatment with abarelix in patients with androgen-independent prostate cancer after orchiectomy results in marked reduction in circulating FSH. None of the patients met the PSA response criteria; nonetheless, minor reductions in serum PSA were observed in 5 of 16 patients.
Collapse
Affiliation(s)
- Tomasz M Beer
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Portland, Oregon 97239, USA
| | | | | | | | | |
Collapse
|
19
|
Miles LEC, Hanyaloglu AC, Dromey JR, Pfleger KDG, Eidne KA. Gonadotropin-releasing hormone receptor-mediated growth suppression of immortalized LbetaT2 gonadotrope and stable HEK293 cell lines. Endocrinology 2004; 145:194-204. [PMID: 14551223 DOI: 10.1210/en.2003-0551] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Continuous administration of GnRH analogs results in an inhibition of tumor growth that may be mediated in part by direct activation of GnRH receptors (GnRHRs) expressed on tumor cells. However, it is not fully understood how the GnRHR mediates these growth effects. This study aimed to determine how the presence or absence of this receptor in different cell types might affect the ability of GnRH to directly mediate growth effects. We demonstrate that continuous treatment with GnRH or a GnRH agonist (GnRHA) induces an antiproliferative effect in a gonadotrope-derived cell line (LbetaT2) and also in HEK293 cells stably expressing either the rat or human GnRHR. The antiproliferative effect was time and dose dependent and was verified using [3H]thymidine incorporation, light microscopy, and analysis of cell number. Inhibition was specifically mediated via the GnRHR, as cotreatment of the GnRHR-expressing cell lines with a GnRH antagonist blocked the growth-suppressive effect induced by GnRHA treatment. Cell cycle analysis revealed that GnRHA-treated HEK/GnRHR cell lines induced an accumulation of cells in the G2/M phase, whereas a G0/G1 arrest was observed in LbetaT2 cells. GnRHA treatment also caused a small, but significant, increase in apoptotic cells. This study provides evidence for a direct role for the GnRHR in mediating antiproliferative events in two cell systems, neither of which was derived from extrapituitary reproductive tumors. The ability to induce these effects, regardless of the cell system involved, has implications regarding the use of GnRH analogs for the treatment of endocrine-related disorders and tumors.
Collapse
Affiliation(s)
- Lauren E C Miles
- Western Australian Institute for Medical Research, Sir Charles Gairdner Hospital, University of Western Australia, Nedlands, Perth, Australia
| | | | | | | | | |
Collapse
|