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Kim MA, Kim TH, Kannan P, Kho KH, Park K, Sohn YC. Functional Characterization of Gonadotropin-Releasing Hormone and Corazonin Signaling Systems in Pacific Abalone: Toward Reclassification of Invertebrate Neuropeptides. Neuroendocrinology 2023; 114:64-89. [PMID: 37703838 DOI: 10.1159/000533662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/14/2023] [Indexed: 09/15/2023]
Abstract
INTRODUCTION The proposed evolutionary origins and corresponding nomenclature of bilaterian gonadotropin-releasing hormone (GnRH)-related neuropeptides have changed tremendously with the aid of receptor deorphanization. However, the reclassification of the GnRH and corazonin (CRZ) signaling systems in Lophotrochozoa remains unclear. METHODS We characterized GnRH and CRZ receptors in the mollusk Pacific abalone, Haliotis discus hannai (Hdh), by phylogenetic and gene expression analyses, bioluminescence-based reporter, Western blotting, substitution of peptide amino acids, in vivo neuropeptide injection, and RNA interference assays. RESULTS Two Hdh CRZ-like receptors (Hdh-CRZR-A and Hdh-CRZR-B) and three Hdh GnRH-like receptors (Hdh-GnRHR1-A, Hdh-GnRHR1-B, and Hdh-GnRHR2) were identified. In phylogenetic analysis, Hdh-CRZR-A and -B grouped within the CRZ-type receptors, whereas Hdh-GnRHR1-A/-B and Hdh-GnRHR2 clustered within the GnRH/adipokinetic hormone (AKH)/CRZ-related peptide-type receptors. Hdh-CRZR-A/-B and Hdh-GnRHR1-A were activated by Hdh-CRZ (pQNYHFSNGWHA-NH2) and Hdh-GnRH (pQISFSPNWGT-NH2), respectively. Hdh-CRZR-A/-B dually coupled with the Gαq and Gαs signaling pathways, whereas Hdh-GnRHR1-A was linked only with Gαq signaling. Analysis of substituted peptides, [I2S3]Hdh-CRZ and [N2Y3H4]Hdh-GnRH, and in silico docking models revealed that the N-terminal amino acids of the peptides are critical for the selectivity of Hdh-CRZR and Hdh-GnRHR. Two precursor transcripts for Hdh-CRZ and Hdh-GnRH peptides and their receptors were mainly expressed in the neural ganglia, and their levels increased in starved abalones. Injection of Hdh-CRZ peptide into abalones decreased food consumption, whereas Hdh-CRZR knockdown increased food consumption. Moreover, Hdh-CRZ induced germinal vesicle breakdown in mature oocytes. CONCLUSION Characterization of Hdh-CRZRs and Hdh-GnRHRs and their cognate peptides provides new insight into the evolutionary route of GnRH-related signaling systems in bilaterians.
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Affiliation(s)
- Mi Ae Kim
- Department of Marine Bioscience, Gangneung-Wonju National University, Gangneung, Republic of Korea
- East Coast Life Sciences Institute, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Tae Ha Kim
- Department of Marine Bioscience, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Priyadharshini Kannan
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, Republic of Korea
- Department of Biochemical Engineering, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Kang Hee Kho
- Department of Fisheries Science, Chonnam National University, Yeosu, Republic of Korea
| | - Keunwan Park
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, Republic of Korea
| | - Young Chang Sohn
- Department of Marine Bioscience, Gangneung-Wonju National University, Gangneung, Republic of Korea
- East Coast Life Sciences Institute, Gangneung-Wonju National University, Gangneung, Republic of Korea
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Tzoupis H, Nteli A, Androutsou ME, Tselios T. Gonadotropin-Releasing Hormone and GnRH Receptor: Structure, Function and Drug Development. Curr Med Chem 2021; 27:6136-6158. [PMID: 31309882 DOI: 10.2174/0929867326666190712165444] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 01/11/2023]
Abstract
BACKGROUND Gonadotropin-Releasing Hormone (GnRH) is a key element in sexual maturation and regulation of the reproductive cycle in the human organism. GnRH interacts with the pituitary cells through the activation of the Gonadotropin Releasing Hormone Receptors (GnRHR). Any impairments/dysfunctions of the GnRH-GnRHR complex lead to the development of various cancer types and disorders. Furthermore, the identification of GnRHR as a potential drug target has led to the development of agonist and antagonist molecules implemented in various treatment protocols. The development of these drugs was based on the information derived from the functional studies of GnRH and GnRHR. OBJECTIVE This review aims at shedding light on the versatile function of GnRH and GnRH receptor and offers an apprehensive summary regarding the development of different agonists, antagonists and non-peptide GnRH analogues. CONCLUSION The information derived from these studies can enhance our understanding of the GnRH-GnRHR versatile nature and offer valuable insight into the design of new more potent molecules.
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Affiliation(s)
| | - Agathi Nteli
- Department of Chemistry, University of Patras, Rion GR-26504, Greece
| | - Maria-Eleni Androutsou
- Vianex S.A., Tatoiou Str., 18th km Athens-Lamia National Road, Nea Erythrea 14671, Greece
| | - Theodore Tselios
- Department of Chemistry, University of Patras, Rion GR-26504, Greece
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Kotarba G, Zielinska-Gorska M, Biernacka K, Gajewska A. Gonadotropin-releasing hormone-Cu complex (Cu-GnRH) transcriptional activity in vivo in the female rat anterior pituitary gland. Brain Res Bull 2020; 156:67-75. [PMID: 31931118 DOI: 10.1016/j.brainresbull.2020.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 12/23/2019] [Accepted: 01/03/2020] [Indexed: 12/01/2022]
Abstract
Unlike gonadotropin-releasing hormone (GnRH) analogues characterized by amino acid replacement in decapeptide primary structure, Cu-GnRH molecule preserves the native sequence but contains a Cu2+ ion stably bound to the nitrogen atoms including that of the imidazole ring of His2. Cu-GnRH can operate via cAMP/PKA signalling in anterior pituitary cells, suggesting that it may affect selected gonadotropic network gene transcription in vivo. We analysed pituitary mRNA expression of Egr-1, Nr5a1, and Lhb based on their role in luteinizing hormone (LH) synthesis; and Nos1, Adcyap1, and Prkaca due to their dependence on cAMP/PKA activity. In two independent experiments, ovariectomized rats received intracerebroventricular pulsatile (one pulse/h or two pulses/h over 5 h) microinjections of 2 nM Cu-GnRH; 2 nM antide (GnRH antagonist) + 2 nM Cu-GnRH; 100 nM PACAP6-38 (PACAP receptor antagonist) + 2 nM Cu-GnRH. Relative expression of selected mRNAs was determined by qRT-PCR. LH serum concentration was examined according to RIA. All examined genes responded to Cu-GnRH stimulation with increased transcriptional activity in a manner dependent on pulse frequency pattern. Increased expression of Nr5a1, Lhb, Nos1, Adcyap1, and Prkaca mRNA was observed solely in rats receiving the complex with frequency of two pulses/h over 5 h. Egr-1 transcription was up-regulated for both applied Cu-GnRH pulsatile patterns. The stimulatory effect of Cu-GnRH on gene transcription was dependent on both GnRH receptor and PAC-1 activation. In conclusion, obtained results indicate that Cu-GnRH complex is a GnRH analogue able to induce both IP3/PKC and cAMP/PKA-dependent gonadotrope network gene transcription in vivo.
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Affiliation(s)
- Grzegorz Kotarba
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland.
| | - Marlena Zielinska-Gorska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland.
| | - Katarzyna Biernacka
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland
| | - Alina Gajewska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland.
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Synthesis, Stability and Direct Antiproliferative Effect of New Cysteine Modified GnRH Analogs. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-018-9781-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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5
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Schuster S, Biri-Kovács B, Szeder B, Farkas V, Buday L, Szabó Z, Halmos G, Mező G. Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin-GnRH-III conjugates developed for targeted drug delivery. Beilstein J Org Chem 2018; 14:756-771. [PMID: 29719573 PMCID: PMC5905287 DOI: 10.3762/bjoc.14.64] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/15/2018] [Indexed: 12/18/2022] Open
Abstract
Gonadotropin releasing hormone-III (GnRH-III), a native isoform of the human GnRH isolated from sea lamprey, specifically binds to GnRH receptors on cancer cells enabling its application as targeting moieties for anticancer drugs. Recently, we reported on the identification of a novel daunorubicin–GnRH-III conjugate (GnRH-III–[4Lys(Bu), 8Lys(Dau=Aoa)] with efficient in vitro and in vivo antitumor activity. To get a deeper insight into the mechanism of action of our lead compound, the cellular uptake was followed by confocal laser scanning microscopy. Hereby, the drug daunorubicin could be visualized in different subcellular compartments by following the localization of the drug in a time-dependent manner. Colocalization studies were carried out to prove the presence of the drug in lysosomes (early stage) and on its site of action (nuclei after 10 min). Additional flow cytometry studies demonstrated that the cellular uptake of the bioconjugate was inhibited in the presence of the competitive ligand triptorelin indicating a receptor-mediated pathway. For comparative purpose, six novel daunorubicin–GnRH-III bioconjugates have been synthesized and biochemically characterized in which 6Asp was replaced by D-Asp, D-Glu and D-Trp. In addition to the analysis of the in vitro cytostatic effect and cellular uptake, receptor binding studies with 125I-triptorelin as radiotracer and degradation of the GnRH-III conjugates in the presence of rat liver lysosomal homogenate have been performed. All derivatives showed high binding affinities to GnRH receptors and displayed in vitro cytostatic effects on HT-29 and MCF-7 cancer cells with IC50 values in a low micromolar range. Moreover, we found that the release of the active drug metabolite and the cellular uptake of the bioconjugates were strongly affected by the amino acid exchange which in turn had an impact on the antitumor activity of the bioconjugates.
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Affiliation(s)
- Sabine Schuster
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, 1117 Budapest, Hungary.,Institute of Chemistry, Eötvös L. University, 1117 Budapest, Hungary
| | - Beáta Biri-Kovács
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, 1117 Budapest, Hungary.,Institute of Chemistry, Eötvös L. University, 1117 Budapest, Hungary
| | - Bálint Szeder
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Viktor Farkas
- MTA-ELTE Protein Modelling Research Group, Hungarian Academy of Sciences, Eötvös L. University, 1117 Budapest, Hungary
| | - László Buday
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Zsuzsanna Szabó
- Department of Biopharmacy, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary
| | - Gábor Halmos
- Department of Biopharmacy, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary
| | - Gábor Mező
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, 1117 Budapest, Hungary.,Institute of Chemistry, Eötvös L. University, 1117 Budapest, Hungary
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Schally AV, Block NL, Rick FG. Discovery of LHRH and development of LHRH analogs for prostate cancer treatment. Prostate 2017; 77:1036-1054. [PMID: 28449236 DOI: 10.1002/pros.23360] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 01/06/2023]
Abstract
The discovery, isolation, elucidation of structure, synthesis, and initial testing of the neuropeptide hypothalamic luteinizing hormone-releasing hormone (LHRH), which regulates reproduction, is briefly described. The design, synthesis, and experimental and clinical testing of agonistic analogs of LHRH is extensively reviewed focusing on the development of new methods for the treatment of prostate cancer. Subsequent development of antagonistic analogs of LHRH is then faithfully recounted with special emphasis on therapy of prostate cancer and BPH. The concepts of targeted therapy to peptide receptors on tumors are re-examined and the development of the cytotoxic analogs of LHRH and their status is reviewed. The endeavor to develop better therapies for prostate cancer, based on LHRH analogs, guided much of our work.
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Affiliation(s)
- Andrew V Schally
- Veterans Affairs Medical Center and South Florida Veterans Affairs Foundation for Research and Education, Miami, Florida
- Department of Pathology, University of Miami Miller School of Medicine, Miami, Florida
- Division of Hematology/Oncology, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
- Division of Endocrinology, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida
| | - Norman L Block
- Department of Pathology, University of Miami Miller School of Medicine, Miami, Florida
- Division of Hematology/Oncology, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida
| | - Ferenc G Rick
- Veterans Affairs Medical Center and South Florida Veterans Affairs Foundation for Research and Education, Miami, Florida
- Department of Urology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida
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Sakhteman A, Khoddami M, Negahdaripour M, Mehdizadeh A, Tatar M, Ghasemi Y. Exploring 3D structure of human gonadotropin hormone receptor at antagonist state using homology modeling, molecular dynamic simulation, and cross-docking studies. J Mol Model 2016; 22:225. [PMID: 27561920 DOI: 10.1007/s00894-016-3091-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
Human gonadotropin hormone receptor, a G-protein coupled receptor, is the target of many medications used in fertility disorders. Obtaining more structural information about the receptor could be useful in many studies related to drug design. In this study, the structure of human gonadotropin receptor was subjected to homology modeling studies and molecular dynamic simulation within a DPPC lipid bilayer for 100 ns. Several frames were thereafter extracted from simulation trajectories representing the receptor at different states. In order to find a proper model of the receptor at the antagonist state, all frames were subjected to cross-docking studies of some antagonists with known experimental values (Ki). Frame 194 revealed a reasonable correlation between docking calculated energy scores and experimental activity values (|r| = 0.91). The obtained correlation was validated by means of SSLR and showed the presence of no chance correlation for the obtained model. Different structural features reported for the receptor, such as two disulfide bridges and ionic lock between GLU90 and LYS 121 were also investigated in the final model.
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Affiliation(s)
- Amirhossein Sakhteman
- Department of Medicinal Chemistry, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran. .,Medicinal Chemistry and Natural Products Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
| | | | - Manica Negahdaripour
- Department of Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Arash Mehdizadeh
- Department of Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohsen Tatar
- Department of Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Younes Ghasemi
- Department of Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
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8
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Szabó I, Bősze S, Orbán E, Sipos É, Halmos G, Kovács M, Mező G. Comparative in vitro biological evaluation of daunorubicin containing GnRH-I and GnRH-II conjugates developed for tumor targeting. J Pept Sci 2015; 21:426-35. [PMID: 25908176 DOI: 10.1002/psc.2775] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/27/2015] [Accepted: 03/04/2015] [Indexed: 12/22/2022]
Abstract
Hormone based drug targeting is a promising tool for selective tumor therapy. In this study, synthesis and systematic comparative biological evaluation of novel drug containing analogs of gonadotropin-releasing hormone GnRH-I and GnRH-II is reported demonstrating their suitability for tumor targeting. The cytotoxic conjugates were prepared by the attachment of the chemotherapeutical agent daunorubicin (Dau) to GnRH analogs directly or through an enzyme-labile spacer with oxime linkage. All conjugates were found to be proteolytically stable under circumstances applied in biological assays. Both GnRH-I and GnRH-II were able to bind similarly to high-affinity GnRH-I receptors on human pituitary and human prostate cancer cells. The in vitro long-term cytotoxic effect of the conjugates was comparable with that of the free drug in human breast and colon cancer cell lines. Furthermore, a concentration-dependent cellular uptake profile was observed. The in vitro apoptotic effect of the compounds was evaluated by flow cytometry analysis using annexin-V. Our results show that both the GnRH-I and the GnRH-II based analogs might be applied for targeted tumor therapy.
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Affiliation(s)
- Ildikó Szabó
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, 1117, Budapest, Hungary
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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]
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10
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Morgan K, Leighton SP, Millar RP. Probing the GnRH receptor agonist binding site identifies methylated triptorelin as a new anti-proliferative agent. JOURNAL OF MOLECULAR BIOCHEMISTRY 2012; 1:86-98. [PMID: 24490142 PMCID: PMC3906704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
D-amino acid substitutions at glycine postion 6 in GnRH-I decapeptide can possess super-agonist activity and enhanced in vivo pharmacokinetics. Agonists elicit growth-inhibition in tumorigenic cells expressing the GnRH receptor above threshold levels. However, new agonists with modified properties are required to improve the anti-proliferative range. Effects of residue substitutions and methylations on tumourigenic HEK293[SCL60] and WPE-1-NB26-3 prostate cells expressing the rat GnRH receptor were compared. Peptides were ranked according to receptor binding affinity, induction of inositol phosphate production and cell growth-inhibition. Analogues possessing D-Trp6 (including triptorelin), D-Leu6 (including leuprolide), D-Ala6, D-Lys6, or D-Arg6 exhibited agonist and anti-proliferative activity. Residues His5 or His5,Trp7,Tyr8, corresponding to residues found in GnRH-II, were tolerated, with retention of sub-nanomolar/low nanomolar binding affinities and EC50s for receptor activation and IC50s for cell growth-inhibition. His5D-Arg6-GnRH-I exhibited reduced binding affinity and potency, effective in the mid-nanomolar range. However, all GnRH-II-like analogues were less potent than triptorelin. By comparison, three methylated-Trp6 triptorelin variants showed differential binding, receptor activation and anti-proliferation potency. Significantly, 5-Methyl-DL-Trp6-Triptorelin was equipotent to triptorelin. Subsequent studies should determine whether pharmacologically enhanced derivatives of triptorelin can be developed by further alkylations, without substitutions or cleavable cytotoxic adducts, to improve the extent of growth-inhibition of tumour cells expressing the GnRH receptor.
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Affiliation(s)
- Kevin Morgan
- Medical Research Council Human Reproductive Sciences Unit, The Queens Medical Research Institute, Edinburgh, Scotland EH16 4TJ, United Kingdom
| | - Samuel P Leighton
- Medical Research Council Human Reproductive Sciences Unit, The Queens Medical Research Institute, Edinburgh, Scotland EH16 4TJ, United Kingdom
| | - Robert P Millar
- Medical Research Council Human Reproductive Sciences Unit, The Queens Medical Research Institute, Edinburgh, Scotland EH16 4TJ, United Kingdom
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Martin B, Chadwick W, Yi T, Park SS, Lu D, Ni B, Gadkaree S, Farhang K, Becker KG, Maudsley S. VENNTURE--a novel Venn diagram investigational tool for multiple pharmacological dataset analysis. PLoS One 2012; 7:e36911. [PMID: 22606307 PMCID: PMC3351456 DOI: 10.1371/journal.pone.0036911] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 04/10/2012] [Indexed: 12/24/2022] Open
Abstract
As pharmacological data sets become increasingly large and complex, new visual analysis and filtering programs are needed to aid their appreciation. One of the most commonly used methods for visualizing biological data is the Venn diagram. Currently used Venn analysis software often presents multiple problems to biological scientists, in that only a limited number of simultaneous data sets can be analyzed. An improved appreciation of the connectivity between multiple, highly-complex datasets is crucial for the next generation of data analysis of genomic and proteomic data streams. We describe the development of VENNTURE, a program that facilitates visualization of up to six datasets in a user-friendly manner. This program includes versatile output features, where grouped data points can be easily exported into a spreadsheet. To demonstrate its unique experimental utility we applied VENNTURE to a highly complex parallel paradigm, i.e. comparison of multiple G protein-coupled receptor drug dose phosphoproteomic data, in multiple cellular physiological contexts. VENNTURE was able to reliably and simply dissect six complex data sets into easily identifiable groups for straightforward analysis and data output. Applied to complex pharmacological datasets, VENNTURE's improved features and ease of analysis are much improved over currently available Venn diagram programs. VENNTURE enabled the delineation of highly complex patterns of dose-dependent G protein-coupled receptor activity and its dependence on physiological cellular contexts. This study highlights the potential for such a program in fields such as pharmacology, genomics, and bioinformatics.
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Affiliation(s)
- Bronwen Martin
- Metabolism Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Wayne Chadwick
- Receptor Pharmacology Unit, Laboratory of Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Tie Yi
- Metabolism Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Sung-Soo Park
- Receptor Pharmacology Unit, Laboratory of Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Daoyuan Lu
- Receptor Pharmacology Unit, Laboratory of Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Bin Ni
- Receptor Pharmacology Unit, Laboratory of Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Shekhar Gadkaree
- Diabetes Section, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Kathleen Farhang
- Diabetes Section, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Kevin G. Becker
- Gene Expression and Genomics Unit, Research Resources Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Stuart Maudsley
- Receptor Pharmacology Unit, Laboratory of Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
- * E-mail:
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Manea M, Leurs U, Orbán E, Baranyai Z, Öhlschläger P, Marquardt A, Schulcz Á, Tejeda M, Kapuvári B, Tóvári J, Mező G. Enhanced Enzymatic Stability and Antitumor Activity of Daunorubicin-GnRH-III Bioconjugates Modified in Position 4. Bioconjug Chem 2011; 22:1320-9. [DOI: 10.1021/bc100547p] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Marilena Manea
- Laboratory of Analytical Chemistry and Biopolymer Structure Analysis, Department of Chemistry
- Zukunftskolleg
| | - Ulrike Leurs
- Laboratory of Analytical Chemistry and Biopolymer Structure Analysis, Department of Chemistry
| | - Erika Orbán
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary
| | - Zsuzsa Baranyai
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary
| | | | | | - Ákos Schulcz
- National Institute of Oncology, 1122 Budapest, Hungary
| | - Miguel Tejeda
- National Institute of Oncology, 1122 Budapest, Hungary
| | | | - József Tóvári
- National Institute of Oncology, 1122 Budapest, Hungary
| | - Gábor Mező
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary
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13
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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.
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Affiliation(s)
- Kevin Morgan
- Medical Research Council Human Reproductive Sciences Unit, The Queen's Medical Research Institute, Little France Crescent, Edinburgh, UK.
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Armstrong S, Caunt C, Finch A, McArdle C. Using automated imaging to interrogate gonadotrophin-releasing hormone receptor trafficking and function. Mol Cell Endocrinol 2011; 331:194-204. [PMID: 20688134 PMCID: PMC3021717 DOI: 10.1016/j.mce.2010.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 05/07/2010] [Accepted: 07/13/2010] [Indexed: 01/03/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH) acts via seven transmembrane receptors on gonadotrophs to stimulate gonadotrophin synthesis and secretion, and thereby mediates central control of reproduction. Type I mammalian GnRHR are unique, in that they lack C-terminal tails. This is thought to underlie their resistance to rapid homologous desensitisation as well as their slow rate of internalisation and inability to provoke G-protein-independent (arrestin-mediated) signalling. More recently it has been discovered that the vast majority of human GnRHR are actually intracellular, in spite of the fact that they are activated at the cell surface by a membrane impermeant peptide hormone. This apparently reflects inefficient exit from the endoplasmic reticulum and again, the absence of the C-tail likely contributes to their intracellular localisation. This review is intended to cover some of these novel aspects of GnRHR biology, focusing on ways that we have used automated fluorescence microscopy (high content imaging) to explore GnRHR localisation and trafficking as well as spatial and temporal aspects of GnRH signalling via the Ca(2+)/calmodulin/calcineurin/NFAT and Raf/MEK/ERK pathways.
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Affiliation(s)
- S.P. Armstrong
- University of Bristol, School of Clinical Sciences, Labs. for Integrative Neuroscience and Endocrinology, 1 Whitson Street, Bristol BS1 3NY, UK
| | - C.J. Caunt
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - A.R. Finch
- University of Bristol, School of Clinical Sciences, Labs. for Integrative Neuroscience and Endocrinology, 1 Whitson Street, Bristol BS1 3NY, UK
| | - C.A. McArdle
- University of Bristol, School of Clinical Sciences, Labs. for Integrative Neuroscience and Endocrinology, 1 Whitson Street, Bristol BS1 3NY, UK
- Corresponding author.
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15
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Wang L, Chadwick W, Park SS, Zhou Y, Silver N, Martin B, Maudsley S. Gonadotropin-releasing hormone receptor system: modulatory role in aging and neurodegeneration. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2010; 9:651-60. [PMID: 20632963 PMCID: PMC2967575 DOI: 10.2174/187152710793361559] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 02/25/2010] [Indexed: 12/15/2022]
Abstract
Receptors for hormones of the hypothalamic-pituitary-gonadal axis are expressed throughout the brain. Age-related decline in gonadal reproductive hormones cause imbalances of this axis and many hormones in this axis have been functionally linked to neurodegenerative pathophysiology. Gonadotropin-releasing hormone (GnRH) plays a vital role in both central and peripheral reproductive regulation. GnRH has historically been known as a pituitary hormone; however, in the past few years, interest has been raised in GnRH actions at non-pituitary peripheral targets. GnRH ligands and receptors are found throughout the brain where they may act to control multiple higher functions such as learning and memory function and feeding behavior. The actions of GnRH in mammals are mediated by the activation of a unique rhodopsin-like G protein-coupled receptor that does not possess a cytoplasmic carboxyl terminal sequence. Activation of this receptor appears to mediate a wide variety of signaling mechanisms that show diversity in different tissues. Epidemiological support for a role of GnRH in central functions is evidenced by a reduction in neurodegenerative disease after GnRH agonist therapy. It has previously been considered that these effects were not via direct GnRH action in the brain, however recent data has pointed to a direct central action of these ligands outside the pituitary. We have therefore summarized the evidence supporting a central direct role of GnRH ligands and receptors in controlling central nervous physiology and pathophysiology.
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Affiliation(s)
- Liyun Wang
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
| | - Wayne Chadwick
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
| | - Soo-Sung Park
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
| | - Yu Zhou
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
| | - Nathan Silver
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
| | - Bronwen Martin
- Metabolism Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
| | - Stuart Maudsley
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore MD 21224
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16
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Shaw ND, Histed SN, Srouji SS, Yang J, Lee H, Hall JE. Estrogen negative feedback on gonadotropin secretion: evidence for a direct pituitary effect in women. J Clin Endocrinol Metab 2010; 95:1955-61. [PMID: 20133465 PMCID: PMC2853991 DOI: 10.1210/jc.2009-2108] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Studies in humans and animals indicate that estrogen negative feedback occurs at the level of the hypothalamus, but it is unclear whether estrogen also exerts an inhibitory effect directly at the pituitary. OBJECTIVES The aim of the study was to determine whether estrogen has a direct negative feedback effect at the pituitary and whether this varies with aging. DESIGN AND SETTING A GnRH antagonist and graded doses of GnRH were used to isolate pituitary responsiveness before and after estrogen administration in Clinical Research Center studies at an academic medical center. SUBJECTS Subjects were healthy postmenopausal women aged 48-56 yr (n = 8) or 70-75 yr (n= 8). INTERVENTIONS A suppressive dose of the NAL-GLU GnRH antagonist was administered, followed by graded doses of GnRH before and after 1 month of estrogen administration. RESULTS LH and FSH responses to GnRH decreased after estrogen administration (P = 0.01 and P = 0.0001, respectively). The ratio of FSH to LH amplitudes decreased in response to estrogen (P = 0.04) indicating a greater sensitivity of FSH than LH to inhibition by estrogen. The inhibitory effect of estrogen on FSH was attenuated with aging (P = 0.02), but was maintained for LH (P = 0.4). CONCLUSIONS Studies that control for endogenous GnRH and estradiol demonstrate a direct pituitary site of estrogen negative feedback on LH and FSH responsiveness to GnRH in women. The effect of estrogen on FSH responsiveness is greater than on LH and is attenuated with aging. These studies indicate that estrogen negative feedback occurs directly at the pituitary and contributes to the differential regulation of FSH and LH secretion.
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Affiliation(s)
- N D Shaw
- Reproductive Endocrine Unit, BHX-5, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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17
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Abstract
I (R.P.M.) presented "The Year In G Protein-Coupled Receptor Research" at ENDO 2009. I first described the diversity of ligands and the five families into which the approximately 800 G protein-coupled receptors (GPCRs) are grouped, their basic structural architectures, their preeminent role in signaling, and the enormous scope for developing drugs targeted at GPCRs. I then spoke about some of the exciting breakthroughs in solving the atomic level structures of the active state of rhodopsin, beta(2)-adrenergic, beta(1)-adrenergic, and A(2A)-adenosine receptors. I also described studies on the structural changes accompanying the activation of the rhodopsin family of GPCRs. From these recent technical advances, we can anticipate that many more GPCR structures will emerge, which will afford us greater insight into their common and unique structural features and, particularly, the mechanisms underlying their activation. These insights will guide us in our understanding of how GPCRs operate, both in the normal and pathological situation. Although these crystal structures are highly informative, it is important to recognize that they represent static frozen conformations of a single GPCR state. New biophysical techniques are therefore being utilized to facilitate the dynamic monitoring of GPCR structural changes in relation to ligand activation. Solving of the crystal structures of GPCRs has also presented the real possibility of using the information of the ligand-binding pocket to allow in silico screening for novel small-molecule ligands. I then reviewed the concept of ligand-induced selective signaling of GPCRs, which is opening up new insights into more selective drug development. The assembly of GPCRs as homo- and heterooligomers and their phosphorylation and association with a vast array of trafficking and signal-modulating proteins are emerging as major mechanisms underlying the functioning of GPCRs. Differential expression and recruitment of these proteins provide a mechanism for subtle physiological regulation of cellular activity. Finally, I mentioned some of the GPCRs that have lately come to the fore as novel regulators in endocrinology. These included fatty acid-specific GPCRs expressed in pancreatic beta-cells and novel neuroendocrine GPCRs regulating reproduction.
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Affiliation(s)
- Robert P Millar
- Medical Research Council (MRC) Human Reproductive Sciences Unit, The Queen's Medical Research Institute, Edinburgh, Scotland, United Kingdom.
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Finch AR, Caunt CJ, Armstrong SP, McArdle CA. Plasma membrane expression of gonadotropin-releasing hormone receptors: regulation by peptide and nonpeptide antagonists. Mol Endocrinol 2009; 24:423-35. [PMID: 20009083 DOI: 10.1210/me.2009-0343] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Gonadotropin-releasing hormone acts via cell surface receptors but most human (h) GnRH receptors (GnRHRs) are intracellular. A membrane-permeant nonpeptide antagonist [(2S)-2-[5-[2-(2-axabicyclo[2.2.2]oct-2-yl)-1,1-dimethy-2-oxoethyl]-2-(3,5-dimethylphenyl)-1H-indol-3-yl]-N-(2-pyridin-4-ylethyl)propan-1-amine (IN3)] increases hGnRHR expression at the surface, apparently by facilitating its exit from the endoplasmic reticulum. Here we have quantified GnRHR by automated imaging in HeLa cells transduced with adenovirus expressing hemagglutinin-tagged GnRHR. Consistent with an intracellular site of action, IN3 increases cell surface hGnRHR, and this effect is not blocked or mimicked by membrane-impermeant peptide antagonists [Ac-D2Nal-D4Cpa-D3Pal-Ser-Tyr-d-Cit-Leu-Arg-Pro-d-Ala-NH(2) (cetrorelix) and antide]. However, when the C-terminal tail of a Xenopus (X) GnRHR was added (h.XGnRHR) to increase expression, both peptides further increased cell surface GnRHR. Cetrorelix also synergized with IN3 to increase expression of hGnRHR and a G-protein coupling-deficient mutant (A261K-hGnRHR). Cetrorelix also increased cell surface expression of hGnRHR, h.XGnRHR, and mouse GnRHR in gonadotrope-lineage LbetaT2 cells, and in HeLa cells it slowed h.XGnRHR internalization (measured by receptor-mediated antihemagglutinin uptake). Thus cetrorelix has effects other than GnRHR blockade; it acts as an inverse agonist in internalization assays, supporting the potential importance of ligand-biased efficacy at GnRHR. We also developed an imaging assay for GnRH function based on Ca(2+)-dependent nuclear translocation of a nuclear factor of activated T cells reporter. Using this in HeLa and LbetaT2 cells, IN3 and cetrorelix behaved as competitive antagonists when coincubated with GnRH, and long-term pretreatment (16 h) with IN3 reduced its effectiveness as an inhibitor whereas pretreatment with cetrorelix increased its inhibitory effect. This distinction between peptide and nonpeptide antagonists may prove important for therapeutic applications of GnRH antagonists.
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Affiliation(s)
- Ann R Finch
- Laboratory for Integrative Neuroscience, Department of Clinical Sciences at South Bristol, Whitson Street, Bristol BS1 3NY, United Kingdom
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GABAergic transmission to gonadotropin-releasing hormone (GnRH) neurons is regulated by GnRH in a concentration-dependent manner engaging multiple signaling pathways. J Neurosci 2009; 29:9809-18. [PMID: 19657033 DOI: 10.1523/jneurosci.2509-09.2009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) neurons are the central regulators of fertility. GnRH stimulates or inhibits GnRH neuronal activity depending on dose. The mechanisms for these actions remain unknown. We hypothesized GnRH acts in part by altering fast synaptic transmission to GnRH neurons. GABAergic and glutamatergic postsynaptic currents (PSCs), both of which can excite these neurons, were recorded from GnRH neurons in brain slices from adult intact and orchidectomized (ORX) males. ORX enhanced the frequency of GABA transmission to GnRH neurons, but had no effect on glutamatergic transmission. Effects of ORX on GABAergic transmission were reversed by estradiol replacement, suggesting GABA is a mediator of steroid feedback in males. GABAergic neurons express type-1 GnRH receptor (GnRHR-1). Low GnRH (20 nm) reduced GABAergic PSC frequency in GnRH neurons from both ORX and intact mice. High GnRH (2 microm) had no effect on either GABAergic or glutamatergic transmission to GnRH neurons. To investigate mechanisms mediating low-dose GnRH suppression of GABAergic transmission, GABAergic PSCs were recorded after arresting G(alphai) activity with pertussis toxin (PTX). PTX abolished the suppressive effect of low GnRH. Moreover, PTX uncovered a stimulatory effect of high GnRH on GABAergic transmission. These data suggest low-dose GnRH suppresses GnRH firing rate in part by decreasing GABAergic transmission to the GnRH neurons, independent of gonadal hormone milieu. Low-dose GnRH appears to exert the suppressive effect by activating GnRHR-I coupled to G(alphai). The concentration-dependent effects of GnRH may be mediated in part by changes in affinity of GnRH to GnRHR-I coupled to different G(alpha) proteins.
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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.
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Affiliation(s)
- Kevin Morgan
- Medical Research Council Human Reproductive Sciences Unit, Edinburgh Cancer Research Centre, Edinburgh, United Kingdom.
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