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Casati L, Ciceri S, Maggi R, Bottai D. Physiological and Pharmacological overview of the Gonadotropin Releasing Hormone. Biochem Pharmacol 2023; 212:115553. [PMID: 37075816 DOI: 10.1016/j.bcp.2023.115553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/07/2023] [Accepted: 04/10/2023] [Indexed: 04/21/2023]
Abstract
Gonadotropin-releasing Hormone (GnRH) is a decapeptide responsible for the control of the reproductive functions. It shows C- and N-terminal aminoacid modifications and two other distinct isoforms have been so far identified. The biological effects of GnRH are mediated by binding to high-affinity G-protein couple receptors (GnRHR), showing characteristic very short C tail. In mammals, including humans, GnRH-producing neurons originate in the embryonic nasal compartment and during early embryogenesis they undergo rapid migration towards the hypothalamus; the increasing knowledge of such mechanisms improved diagnostic and therapeutic approaches to infertility. The pharmacological use of GnRH, or its synthetic peptide and non-peptide agonists or antagonists, provides a valid tool for reproductive disorders and assisted reproduction technology (ART). The presence of GnRHR in several organs and tissues indicates additional functions of the peptide. The identification of a GnRH/GnRHR system in the human endometrium, ovary, and prostate has extended the functions of the peptide to the physiology and tumor transformation of such tissues. Likely, the activity of a GnRH/GnRHR system at the level of the hippocampus, as well as its decreased expression in mice brain aging, raised interest in its possible involvement in neurogenesis and neuronal functions. In conclusion, GnRH/GnRHR appears to be a fascinating biological system that exerts several possibly integrated pleiotropic actions in the complex control of reproductive functions, tumor growth, neurogenesis, and neuroprotection. This review aims to provide an overview of the physiology of GnRH and the pharmacological applications of its synthetic analogs in the management of reproductive and non-reproductive diseases.
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Affiliation(s)
- Lavinia Casati
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Samuele Ciceri
- Dept. of Pharmaceutical Sciences (DISFARM), Università degli Studi di Milano, Milano Italy
| | - Roberto Maggi
- Dept. of Pharmaceutical Sciences (DISFARM), Università degli Studi di Milano, Milano Italy.
| | - Daniele Bottai
- Dept. of Pharmaceutical Sciences (DISFARM), Università degli Studi di Milano, Milano Italy
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2
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Schuler G. [Equine chorionic gonadotrophin: Biology and veterinary use]. Tierarztl Prax Ausg G Grosstiere Nutztiere 2020; 48:344-354. [PMID: 33080658 DOI: 10.1055/a-1235-7973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The pituitary gonadotrophins follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play a prominent role in the control of gonadal functions. Therefore, their use in the treatment of fertility disorders (e. g. anovulatory anestrus) as well as in biotechnology (e. g. superovulation, hormone programs for cycle synchronization) is of substantial interest. Preparations of FSH or LH are relatively expensive due to the laborious extraction from pituitary tissue and are therefore reserved for special indications. In primates and equids, the chorionic epithelium expresses an LH-like molecule (chorionic gonadotrophin, CG). Equine CG (eCG) selectively binds to LH receptors in equids. In all other domestic mammalian species, equine CG (eCG) shows an extraordinarily high FSH activity in addition to its LH activity ("dual activity"). Since its market launch, this has therefore gained considerable importance as a comparatively inexpensive FSH analogue, mainly for use in ruminants and pigs. In contrast to the human CG (hCG), which may be isolated non-invasively from the urine of pregnant women and is widely used as LH analogue, eCG must be extracted from the blood of pregnant donor mares, as eCG concentrations in urine are only minimal. Following reports of deaths and suffering of donor mares associated with eCG collection in South American settings, the current practice of eCG production has given rise to increasing public criticism. This has recently led to calls for a general production ban. Primary aim of this review is therefore to summarize the current state of knowledge concerning the properties and biology of this molecule, which is also highly interesting from the point of view of basic science.
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Affiliation(s)
- Gerhard Schuler
- Klinik für Geburtshilfe, Gynäkologie und Andrologie der Groß- und Kleintiere mit Tierärztlicher Ambulanz, Justus-Liebig-Universität Gießen
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3
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Padmanabhan V, Cardoso RC. Neuroendocrine, autocrine, and paracrine control of follicle-stimulating hormone secretion. Mol Cell Endocrinol 2020; 500:110632. [PMID: 31682864 PMCID: PMC7433377 DOI: 10.1016/j.mce.2019.110632] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 12/12/2022]
Abstract
Follicle-stimulating hormone (FSH) is a glycoprotein hormone produced by gonadotropes in the anterior pituitary that plays a central role in controlling ovarian folliculogenesis and steroidogenesis in females. Moreover, recent studies strongly suggest that FSH exerts extragonadal actions, particularly regulating bone mass and adiposity. Despite its crucial role, the mechanisms regulating FSH secretion are not completely understood. It is evident that hypothalamic, ovarian, and pituitary factors are involved in the neuroendocrine, paracrine, and autocrine regulation of FSH production. Large animal models, such as the female sheep, represent valuable research models to investigate specific aspects of FSH secretory processes. This review: (i) summarizes the role of FSH controlling reproduction and other biological processes; (ii) discusses the hypothalamic, gonadal, and pituitary regulation of FSH secretion; (iii) considers the biological relevance of the different FSH isoforms; and (iv) summarizes the distinct patterns of FSH secretion under different physiological conditions.
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4
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Ranđelović I, Schuster S, Kapuvári B, Fossati G, Steinkühler C, Mező G, Tóvári J. Improved In Vivo Anti-Tumor and Anti-Metastatic Effect of GnRH-III-Daunorubicin Analogs on Colorectal and Breast Carcinoma Bearing Mice. Int J Mol Sci 2019; 20:E4763. [PMID: 31557968 PMCID: PMC6801585 DOI: 10.3390/ijms20194763] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 12/19/2022] Open
Abstract
Among various homing devices, gonadotropin-releasing hormone-III (GnRH-III) peptide represents a suitable targeting moiety for drug delivery systems. The anti-tumor activity of the previously developed GnRH-III-[4Lys(Bu),8Lys(Dau=Aoa)] conjugate and the novel synthesized GnRH-III-[2ΔHis,3d-Tic,4Lys(Bu),8Lys(Dau=Aoa)] conjugate, containing the anti-cancer drug daunorubicin, were evaluated. Here, we demonstrate that both GnRH-III-Dau conjugates possess an efficient growth inhibitory effect on more than 20 cancer cell lines, whereby the biological activity is strongly connected to the expression of gonadotropin-releasing hormone receptors (GnRH-R). The novel conjugate showed a higher in vitro anti-proliferative activity and a higher uptake capacity. Moreover, the treatment with GnRH-III-Dau conjugates cause a significant in vivo tumor growth and metastases inhibitory effect in three different orthotopic models, including 4T1 mice and MDA-MB-231 human breast carcinoma, as well as HT-29 human colorectal cancer bearing BALB/s and SCID mice, while toxic side-effects were substantially reduced in comparison to the treatment with the free drug. These findings illustrate that our novel lead compound is a highly promising candidate for targeted tumor therapy in both colon cancer and metastatic breast cancer.
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Affiliation(s)
- Ivan Ranđelović
- Department of Experimental Pharmacology, National Institute of Oncology, 1122 Budapest, Hungary.
| | - Sabine Schuster
- Faculty of Science, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary.
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary.
| | - Bence Kapuvári
- Department of Biochemistry, National Institute of Oncology, 1122 Budapest, Hungary.
| | - Gianluca Fossati
- Preclinical R&D, Italfarmaco SpA, 20092 Cinisello Balsamo (Milan), Italy.
| | | | - Gábor Mező
- Faculty of Science, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary.
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary.
| | - József Tóvári
- Department of Experimental Pharmacology, National Institute of Oncology, 1122 Budapest, Hungary.
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Schuster S, Biri-Kovács B, Szeder B, Buday L, Gardi J, Szabó Z, Halmos G, Mező G. Enhanced In Vitro Antitumor Activity of GnRH-III-Daunorubicin Bioconjugates Influenced by Sequence Modification. Pharmaceutics 2018; 10:E223. [PMID: 30423956 PMCID: PMC6320914 DOI: 10.3390/pharmaceutics10040223] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 12/21/2022] Open
Abstract
Receptors for gonadotropin releasing hormone (GnRH) are highly expressed in various human cancers including breast, ovarian, endometrial, prostate and colorectal cancer. Ligands like human GnRH-I or the sea lamprey analogue GnRH-III represent a promising approach for the development of efficient drug delivery systems for targeted tumor therapy. Here, we report on the synthesis and cytostatic effect of 14 oxime bond-linked daunorubicin GnRH-III conjugates containing a variety of unnatural amino acids within the peptide sequence. All compounds demonstrated a reduced cell viability in vitro on estrogen receptor α (ERα) positive and ERα negative cancer cells. The best candidate revealed an increased cancer cell growth inhibitory effect compared to our lead-compound GnRH-III-[⁴Lys(Bu),⁸Lys(Dau=Aoa)]. Flow cytometry and fluorescence microscopy studies showed that the cellular uptake of the novel conjugate is substantially improved leading to an accelerated delivery of the drug to its site of action. However, the release of the active drug-metabolite by lysosomal enzymes was not negatively affected by amino acid substitution, while the compound provided a high stability in human blood plasma. Receptor binding studies were carried out to ensure a high binding affinity of the new compound for the GnRH-receptor. It was demonstrated that GnRH-III-[²ΔHis,³d-Tic,⁴Lys(Bu),⁸Lys(Dau=Aoa)] is a highly potent and promising anticancer drug delivery system for targeted tumor therapy.
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Affiliation(s)
- Sabine Schuster
- Faculty of Science, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary.
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary.
| | - Beáta Biri-Kovács
- Faculty of Science, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary.
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary.
| | - Bálint Szeder
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences, 1117 Budapest, Hungary.
| | - László Buday
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences, 1117 Budapest, Hungary.
| | - János Gardi
- First Department of Internal Medicine, Faculty of Medicine, University of Szeged, 6720 Szeged, 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
- Faculty of Science, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary.
- MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary.
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Abstract
Gonadotropin-releasing hormone (GnRH) is recognized as the central regulator of the functions of the pituitary-gonadal axis. The increasing knowledge on the mechanisms controlling the development and the function of GnRH-producing neurons is leading to a better diagnostic and therapeutic approach for hypogonadotropic hypogonadisms and for alterations of the puberty onset. During female life span, the function of the GnRH pulse generator may be affected by a number of inputs from other neuronal systems, offering alternative strategies for diagnostic and therapeutic interventions. Moreover, the identification of a GnRH/GnRH receptor system in both human ovary and endometrium has widened the spectrum of action of the peptide outside its hypothalamic functions. The pharmacological use of GnRH itself or its synthetic analogs (agonists and antagonists) provides a valid tool to either stimulate or block gonadotropin secretion and to modulate the female fertility in several reproductive disorders and in assisted reproduction technology. The use of GnRH agonists in young female patients undergoing chemotherapy is also considered a promising therapeutic approach to counteract iatrogenic ovarian failure.
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Hegedüs R, Pauschert A, Orbán E, Szabó I, Andreu D, Marquardt A, Mező G, Manea M. Modification of daunorubicin-GnRH-III bioconjugates with oligoethylene glycol derivatives to improve solubility and bioavailability for targeted cancer chemotherapy. Biopolymers 2016; 104:167-77. [PMID: 25753049 DOI: 10.1002/bip.22629] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/18/2015] [Accepted: 02/24/2015] [Indexed: 12/16/2022]
Abstract
Daunorubicin-GnRH-III bioconjugates have recently been developed as drug delivery systems with potential applications in targeted cancer chemotherapy. In order to improve their biochemical properties, several strategies have been pursued: (1) incorporation of an enzymatic cleavable spacer between the anticancer drug and the peptide-based targeting moiety, (2) peptide modification by short chain fatty acids, or (3) attachment of two anticancer drugs to the same GnRH-III derivative. Although these modifications led to more potent bioconjugates, a decrease in their solubility was observed. Here we report on the design, synthesis and biochemical characterization of daunorubicin-GnRH-III bioconjugates with increased solubility, which could be achieved by incorporating oligoethylene glycol-based spacers in their structure. First, we have evaluated the effect of an oligoethylene glycol-based spacer on the solubility, enzymatic stability/degradation, cellular uptake, and in vitro cytostatic effect of a bioconjugate containing only one daunorubicin attached through a GFLG tetrapeptide spacer to the GnRH-III targeting moiety. Thereafter, more complex compounds containing two copies of daunorubicin, GFLG spacers as well as Lys(nBu) in position 4 of GnRH-III were synthesized and biochemically characterized. Our results indicated that all synthesized oligoethylene glycol-containing bioconjugates had higher solubility in cell culture medium than the unmodified analogs. They were degraded in the presence of rat liver lysosomal homogenate leading to the formation of small drug containing metabolites. In the case of bioconjugates containing two copies of daunorubicin, the incorporation of oligoethylene glycol-based spacers led to increased in vitro cytostatic effect on MCF-7 human breast cancer cells.
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Affiliation(s)
- Rózsa Hegedüs
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös L. University, 1117, Budapest, Hungary
| | - Aline Pauschert
- Department of Chemistry, University of Konstanz, 78457, Konstanz, Germany
| | - Erika Orbán
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös L. University, 1117, Budapest, Hungary
| | - Ildikó Szabó
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös L. University, 1117, Budapest, Hungary
| | - David Andreu
- Department of Experimental and Health Sciences, Pompeu Fabra University, 08003, Barcelona, Spain
| | - Andreas Marquardt
- Proteomics Facility, Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Gábor Mező
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös L. University, 1117, Budapest, Hungary
| | - Marilena Manea
- Department of Chemistry, University of Konstanz, 78457, Konstanz, Germany.,Zukunftskolleg, University of Konstanz, 78457, Konstanz, Germany
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8
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Maggi R, Cariboni AM, Marelli MM, Moretti RM, Andrè V, Marzagalli M, Limonta P. GnRH and GnRH receptors in the pathophysiology of the human female reproductive system. Hum Reprod Update 2015; 22:358-81. [PMID: 26715597 DOI: 10.1093/humupd/dmv059] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/03/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Human reproduction depends on an intact hypothalamic-pituitary-gonadal (HPG) axis. Hypothalamic gonadotrophin-releasing hormone (GnRH) has been recognized, since its identification in 1971, as the central regulator of the production and release of the pituitary gonadotrophins that, in turn, regulate the gonadal functions and the production of sex steroids. The characteristic peculiar development, distribution and episodic activity of GnRH-producing neurons have solicited an interdisciplinary interest on the etiopathogenesis of several reproductive diseases. The more recent identification of a GnRH/GnRH receptor (GnRHR) system in both the human endometrium and ovary has widened the spectrum of action of the peptide and of its analogues beyond its hypothalamic function. METHODS An analysis of research and review articles published in international journals until June 2015 has been carried out to comprehensively summarize both the well established and the most recent knowledge on the physiopathology of the GnRH system in the central and peripheral control of female reproductive functions and diseases. RESULTS This review focuses on the role of GnRH neurons in the control of the reproductive axis. New knowledge is accumulating on the genetic programme that drives GnRH neuron development to ameliorate the diagnosis and treatment of GnRH deficiency and consequent delayed or absent puberty. Moreover, a better understanding of the mechanisms controlling the episodic release of GnRH during the onset of puberty and the ovulatory cycle has enabled the pharmacological use of GnRH itself or its synthetic analogues (agonists and antagonists) to either stimulate or to block the gonadotrophin secretion and modulate the functions of the reproductive axis in several reproductive diseases and in assisted reproduction technology. Several inputs from other neuronal populations, as well as metabolic, somatic and age-related signals, may greatly affect the functions of the GnRH pulse generator during the female lifespan; their modulation may offer new possible strategies for diagnostic and therapeutic interventions. A GnRH/GnRHR system is also expressed in female reproductive tissues (e.g. endometrium and ovary), both in normal and pathological conditions. The expression of this system in the human endometrium and ovary supports its physiological regulatory role in the processes of trophoblast invasion of the maternal endometrium and embryo implantation as well as of follicular development and corpus luteum functions. The GnRH/GnRHR system that is expressed in diseased tissues of the female reproductive tract (both benign and malignant) is at present considered an effective molecular target for the development of novel therapeutic approaches for these pathologies. GnRH agonists are also considered as a promising therapeutic approach to counteract ovarian failure in young female patients undergoing chemotherapy. CONCLUSIONS Increasing knowledge about the regulation of GnRH pulsatile release, as well as the therapeutic use of its analogues, offers interesting new perspectives in the diagnosis, treatment and outcome of female reproductive disorders, including tumoral and iatrogenic diseases.
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Affiliation(s)
- Roberto Maggi
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
| | - Anna Maria Cariboni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
| | - Marina Montagnani Marelli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
| | - Roberta Manuela Moretti
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
| | - Valentina Andrè
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
| | - Monica Marzagalli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
| | - Patrizia Limonta
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via G. Balzaretti, 9, 20133 Milano, Italy
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Ferris JK, Tse MT, Hamson DK, Taves MD, Ma C, McGuire N, Arckens L, Bentley GE, Galea LAM, Floresco SB, Soma KK. Neuronal Gonadotrophin-Releasing Hormone (GnRH) and Astrocytic Gonadotrophin Inhibitory Hormone (GnIH) Immunoreactivity in the Adult Rat Hippocampus. J Neuroendocrinol 2015; 27:772-86. [PMID: 26258544 DOI: 10.1111/jne.12307] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 01/17/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH) and gonadotrophin inhibitory hormone (GnIH) are neuropeptides secreted by the hypothalamus that regulate reproduction. GnRH receptors are not only present in the anterior pituitary, but also are abundantly expressed in the hippocampus of rats, suggesting that GnRH regulates hippocampal function. GnIH inhibits pituitary gonadotrophin secretion and is also expressed in the hippocampus of a songbird; its role outside of the reproductive axis is not well established. In the present study, we employed immunohistochemistry to examine three forms of GnRH [mammalian GnRH-I (mGnRH-I), chicken GnRH-II (cGnRH-II) and lamprey GnRH-III (lGnRH-III)] and GnIH in the adult rat hippocampus. No mGnRH-I and cGnRH-II+ cell bodies were present in the hippocampus. Sparse mGnRH-I and cGnRH-II+ fibres were present within the CA1 and CA3 fields of the hippocampus, along the hippocampal fissure, and within the hilus of the dentate gyrus. No lGnRH-III was present in the rodent hippocampus. GnIH-immunoreactivity was present in the hippocampus in cell bodies that resembled astrocytes. Males had more GnIH+ cells in the hilus of the dentate gyrus than females. To confirm the GnIH+ cell body phenotype, we performed double-label immunofluorescence against GnIH, glial fibrillary acidic protein (GFAP) and NeuN. Immunofluorescence revealed that all GnIH+ cell bodies in the hippocampus also contained GFAP, a marker of astrocytes. Taken together, these data suggest that GnRH does not reach GnRH receptors in the rat hippocampus primarily via synaptic release. By contrast, GnIH might be synthesised locally in the rat hippocampus by astrocytes. These data shed light on the sites of action and possible functions of GnRH and GnIH outside of the hypothalamic-pituitary-gonadal axis.
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Affiliation(s)
- J K Ferris
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - M T Tse
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - D K Hamson
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - M D Taves
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - C Ma
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - N McGuire
- Department of Integrative Biology, University of California-Berkeley, Berkeley, CA, USA
| | - L Arckens
- Laboratory of Neuroplasticity and Neuroproteomics, University of Leuven, Leuven, Belgium
| | - G E Bentley
- Department of Integrative Biology, University of California-Berkeley, Berkeley, CA, USA
| | - L A M Galea
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - S B Floresco
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - K K Soma
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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10
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Fokidis HB, Adomat HH, Kharmate G, Hosseini-Beheshti E, Guns ES, Soma KK. Regulation of local steroidogenesis in the brain and in prostate cancer: lessons learned from interdisciplinary collaboration. Front Neuroendocrinol 2015; 36:108-29. [PMID: 25223867 DOI: 10.1016/j.yfrne.2014.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 11/16/2022]
Abstract
Sex steroids play critical roles in the regulation of the brain and many other organs. Traditionally, researchers have focused on sex steroid signaling that involves travel from the gonads via the circulation to intracellular receptors in target tissues. This classic concept has been challenged, however, by the growing number of cases in which steroids are synthesized locally and act locally within diverse tissues. For example, the brain and prostate carcinoma were previously considered targets of gonadal sex steroids, but under certain circumstances, these tissues can upregulate their steroidogenic potential, particularly when circulating sex steroid concentrations are low. We review some of the similarities and differences between local sex steroid synthesis in the brain and prostate cancer. We also share five lessons that we have learned during the course of our interdisciplinary collaboration, which brought together neuroendocrinologists and cancer biologists. These lessons have important implications for future research in both fields.
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Affiliation(s)
- H Bobby Fokidis
- Department of Biology, Rollins College, Winter Park, FL 37289, USA; Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada.
| | - Hans H Adomat
- Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada
| | | | | | - Emma S Guns
- Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada; Department of Urological Sciences, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kiran K Soma
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Brain Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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11
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Montagnani Marelli M, Manea M, Moretti RM, Marzagalli M, Limonta P. Oxime bond-linked daunorubicin-GnRH-III bioconjugates exert antitumor activity in castration-resistant prostate cancer cells via the type I GnRH receptor. Int J Oncol 2014; 46:243-53. [PMID: 25351635 DOI: 10.3892/ijo.2014.2730] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 08/07/2014] [Indexed: 11/05/2022] Open
Abstract
It is well established that gonadotropin-releasing hormone receptors (GnRH-R) are expressed in different types of cancers, including castration-resistant prostate cancer (CRPC) and mediate the antiproliferative effect of GnRH analogs. Thus, these compounds are employed as targeting moieties to selectively deliver chemotherapeutic agents to cancer cells. GnRH-III, the decapeptide isolated from the sea lamprey brain, has lower potency than GnRH in stimulating gonadotropin secretion, but it exerts antiproliferative effects on many tumors expressing the GnRH-R. GnRH-III-based peptides are considered promising targeting moieties for the preparation of anticancer drug delivery systems. These studies were aimed at i) evaluating the antitumor activity of two cytotoxic oxime bond-linked daunorubicin (Dau)-GnRH-III derivative bioconjugates (Dau-GnRH-III, in which daunorubicin was coupled to the 8Lys in the native form of GnRH-III, and Dau-[4Lys(Ac)]-GnRH-III, in which daunorubicin was attached to the 8Lys of a GnRH-III derivative where 4Ser was replaced by an acetylated lysine) on CRPC cells; and ii) to elucidate the involvement of the classical GnRH-R (type I GnRH-R) in this antitumor activity. Our results demonstrated that both Dau-GnRH-III and Dau-[4Lys(Ac)]-GnRH-III were rapidly internalized into DU145 prostate cancer cells and exerted a significant cytostatic effect. Both bioconjugates increased the levels of the active form of caspase-3, indicating the involvement of apoptosis in their antitumor activity. The antiproliferative effect of both Dau-GnRH-III and Dau-[4Lys(Ac)]-GnRH-III was counteracted by the simultaneous treatment of the cells with Antide, an antagonist of the GnRH-R. Moreover, after silencing the type I GnRH-R the antitumor activity of both bioconjugates was completely abolished. These data demonstrate that in CRPC cells, daunorubicin-GnRH-III derivative bioconjugates: i) inhibit tumor cell proliferation, by triggering the apoptosis process; ii) exert their antitumor effect through the activation of the type I GnRH-R expressed on these cells. Cytotoxic-GnRH-III derivative may represent promising targeted chemotherapeutics for the treatment of CRPC patients.
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Affiliation(s)
| | - Marilena Manea
- Department of Chemistry, University of Konstanz, D-78457 Konstanz, Germany
| | - Roberta M Moretti
- Department of Pharmacological and Biomolecular Sciences, University of Milan, I-20133 Milan, Italy
| | - Monica Marzagalli
- Department of Pharmacological and Biomolecular Sciences, University of Milan, I-20133 Milan, Italy
| | - Patrizia Limonta
- Department of Pharmacological and Biomolecular Sciences, University of Milan, I-20133 Milan, Italy
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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]
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13
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de Jong E, Kauffold J, Engl S, Jourquin J, Maes D. Effect of a GnRH analogue (Maprelin) on the reproductive performance of gilts and sows. Theriogenology 2013; 80:870-7. [PMID: 23987986 DOI: 10.1016/j.theriogenology.2013.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/18/2013] [Accepted: 07/22/2013] [Indexed: 10/26/2022]
Abstract
The ability of peforelin (l-GnRH-III) to stimulate follicular growth, FSH release, and estrus in gilts after altrenogest treatment and in sows after weaning was investigated. In three farrow-to-wean herds, with at least 600 sows and average production performance, 216 gilts, 335 primiparous, and 1299 pluriparous sows were randomly allocated to three treatments: peforelin (M group: Maprelin), eCG (F group: Folligon), and physiological saline solution (C group). Animals were treated 48 hours after their last altrenogest treatment (gilts) or 24 hours after weaning (sows). The weaning-to-estrus interval, estrus duration, estrus rate (ER), pregnancy rate, and total born (TB), live born, and stillborn (SB) numbers were recorded and compared between treatments for the different parity groups (gilts and primiparous and pluriparous sows). Follicle sizes were measured in representative animals from each group on the occasion of their last altrenogest treatment or at weaning, and also on the occasions of their first (FS1) and second (FS2) attempted inseminations. Blood samples were taken to determine FSH concentrations at weaning and 2 hours after injection, and progesterone concentrations 10 days after the first insemination attempt. The relative change in FSH concentrations was calculated. Significant differences were found for ER within 7 days of weaning in pluriparous sows (95%, 91%, and 90% for the M, F, and C groups, respectively, P = 0.005). Gilts in the F-group had high TB numbers, and pluriparous sows in the M group had high SB numbers (TB gilts = 13.6, 15.4, and 14.9 [P = 0.02] and SB pluriparous sows = 1.8, 1.4, and 1.7 [P = 0.05] for the M, F, and C groups, respectively). The M group had the highest FS1 (for gilts) and FS2 (for pluriparous sows) values: FS1 = 5.4, 4.9, and 4.9 mm [P = 0.02] and FS2 = 6.8, 5.3, and 6.3 mm [P = 0.03] for the M, F, and C groups, respectively. There were no significant differences between the different treatments within each parity group with respect to any of the other variables. Overall, peforelin treatment had small but positive effects on the ER and follicle growth in certain parity groups but did not seem to affect litter sizes or FSH and progesterone levels in sows on the occasions of the corresponding examinations.
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Affiliation(s)
- Ellen de Jong
- Department of Reproduction Obstetrics and Herd Health, Unit Porcine Health Management, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium.
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14
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Limonta P, Montagnani Marelli M, Mai S, Motta M, Martini L, Moretti RM. GnRH receptors in cancer: from cell biology to novel targeted therapeutic strategies. Endocr Rev 2012; 33:784-811. [PMID: 22778172 DOI: 10.1210/er.2012-1014] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The crucial role of pituitary GnRH receptors (GnRH-R) in the control of reproductive functions is well established. These receptors are the target of GnRH agonists (through receptor desensitization) and antagonists (through receptor blockade) for the treatment of steroid-dependent pathologies, including hormone-dependent tumors. It has also become increasingly clear that GnRH-R are expressed in cancer tissues, either related (i.e. prostate, breast, endometrial, and ovarian cancers) or unrelated (i.e. melanoma, glioblastoma, lung, and pancreatic cancers) to the reproductive system. In hormone-related tumors, GnRH-R appear to be expressed even when the tumor has escaped steroid dependence (such as castration-resistant prostate cancer). These receptors are coupled to a G(αi)-mediated intracellular signaling pathway. Activation of tumor GnRH-R by means of GnRH agonists elicits a strong antiproliferative, antimetastatic, and antiangiogenic (more recently demonstrated) activity. Interestingly, GnRH antagonists have also been shown to elicit a direct antitumor effect; thus, these compounds behave as antagonists of GnRH-R at the pituitary level and as agonists of the same receptors expressed in tumors. According to the ligand-induced selective-signaling theory, GnRH-R might assume various conformations, endowed with different activities for GnRH analogs and with different intracellular signaling pathways, according to the cell context. Based on these consistent experimental observations, tumor GnRH-R are now considered a very interesting candidate for novel molecular, GnRH analog-based, targeted strategies for the treatment of tumors expressing these receptors. These agents include GnRH agonists and antagonists, GnRH analog-based cytotoxic (i.e. doxorubicin) or nutraceutic (i.e. curcumin) hybrids, and GnRH-R-targeted nanoparticles delivering anticancer compounds.
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Affiliation(s)
- Patrizia Limonta
- Section of Biomedicine and Endocrinology, Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Balzaretti 9, 20133 Milano, Italy.
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Leurs U, Lajkó E, Mező G, Orbán E, Öhlschläger P, Marquardt A, Kőhidai L, Manea M. GnRH-III based multifunctional drug delivery systems containing daunorubicin and methotrexate. Eur J Med Chem 2012; 52:173-83. [DOI: 10.1016/j.ejmech.2012.03.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 03/05/2012] [Accepted: 03/06/2012] [Indexed: 11/16/2022]
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16
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Schlage P, Mező G, Orbán E, Bősze S, Manea M. Anthracycline-GnRH derivative bioconjugates with different linkages: Synthesis, in vitro drug release and cytostatic effect. J Control Release 2011; 156:170-8. [DOI: 10.1016/j.jconrel.2011.08.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/30/2011] [Accepted: 08/05/2011] [Indexed: 01/13/2023]
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17
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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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18
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Leurs U, Mező G, Orbán E, Öhlschläger P, Marquardt A, Manea M. Design, synthesis, in vitro stability and cytostatic effect of multifunctional anticancer drug-bioconjugates containing GnRH-III as a targeting moiety. Biopolymers 2011; 98:1-10. [PMID: 21509746 DOI: 10.1002/bip.21640] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/16/2011] [Accepted: 03/28/2011] [Indexed: 11/09/2022]
Abstract
Bioconjugates containing the GnRH-III hormone decapeptide as a targeting moiety are able to deliver chemotherapeutic agents specifically to cancer cells expressing GnRH receptors, thereby increasing their local efficacy while limiting the peripheral toxicity. However, the number of GnRH receptors on cancer cells is limited and they desensitize under continuous hormone treatment. A possible approach to increase the receptor mediated tumor targeting and consequently the cytostatic effect of the bioconjugates would be the attachment of more than one chemotherapeutic agent to one GnRH-III molecule. Here we report on the design, synthesis and biochemical characterization of multifunctional bioconjugates containing GnRH-III as a targeting moiety and daunorubicin as a chemotherapeutic agent. Two different drug design approaches were pursued. The first one was based on the bifunctional [(4)Lys]-GnRH-III (Glp-His-Trp-Lys-His-Asp-Trp-Lys-Pro-Gly-NH(2)) containing two lysine residues in positions 4 and 8, whose ε-amino groups were used for the coupling of daunorubicin. In the second drug design, the native GnRH-III (Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH(2)) was used as a scaffold; an additional lysine residue was coupled to the ϵ-amino group of (8) Lys in order to generate two free amino groups available for conjugation of daunorubicin. The in vitro stability/degradation of all synthesized compounds was investigated in human serum, as well as in the presence of rat liver lysosomal homogenate. Their cellular uptake was determined on human breast cancer cells and the cytostatic effect was evaluated on human breast, colon and prostate cancer cell lines. Compared with a monofunctional compound, both drug design approaches resulted in multifunctional bioconjugates with increased cytostatic effect.
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Affiliation(s)
- Ulrike Leurs
- Department of Chemistry, Laboratory of Analytical Chemistry and Biopolymer Structure Analysis, University of Konstanz, 78457 Konstanz, Germany
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19
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Brüssow KP, Schneider F, Tuchscherer A, Kanitz W. Influence of synthetic lamprey GnRH-III on gonadotropin release and steroid hormone levels in gilts. Theriogenology 2010; 74:1570-8. [DOI: 10.1016/j.theriogenology.2010.06.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/17/2010] [Accepted: 06/19/2010] [Indexed: 11/30/2022]
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Barretero-Hernandez R, Vizcarra JA, Bowen A, Galyean M. Lamprey GnRH-III Releases Luteinizing Hormone but not Follicle Stimulating Hormone in Pigs. Reprod Domest Anim 2009; 45:983-7. [DOI: 10.1111/j.1439-0531.2009.01471.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Mezo G, Czajlik A, Manea M, Jakab A, Farkas V, Majer Z, Vass E, Bodor A, Kapuvári B, Boldizsár M, Vincze B, Csuka O, Kovács M, Przybylski M, Perczel A, Hudecz F. Structure, enzymatic stability and antitumor activity of sea lamprey GnRH-III and its dimer derivatives. Peptides 2007; 28:806-20. [PMID: 17254668 DOI: 10.1016/j.peptides.2006.12.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 12/19/2006] [Accepted: 12/20/2006] [Indexed: 11/24/2022]
Abstract
Direct antitumor activity of sea lamprey (Petromyzon marinus) gonadotropin-releasing hormone III (Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH(2); lGnRH-III) was described on several tumor cells. To improve the selectivity of antitumor effects without increasing the hormone releasing activity and to enhance the enzymatic stability, lGnRH-III dimers were prepared via disulfide bond formation. Our results demonstrate that the lGnRH-III dimer derivatives exhibited higher antiproliferative effect and enzymatic stability in comparison with the native lGnRH-III, while lower LH-releasing potency was determined. In order to find a correlation between the biological and structural features of these compounds, the conformation of lGnRH-III and its dimer derivatives was determined by ECD, VCD, FT-IR and (1)H NMR.
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Affiliation(s)
- Gábor Mezo
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, POB 32, 1518 Budapest 112, Hungary.
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22
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Kovács M, Vincze B, Horváth JE, Seprodi J. Structure-activity study on the LH- and FSH-releasing and anticancer effects of gonadotropin-releasing hormone (GnRH)-III analogs. Peptides 2007; 28:821-9. [PMID: 17289216 DOI: 10.1016/j.peptides.2007.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 12/29/2006] [Accepted: 01/05/2007] [Indexed: 11/25/2022]
Abstract
UNLABELLED GnRH-III was reported to have selective FSH-releasing activity in rats and significant anticancer potency on human breast cancer cells. To improve either of these effects, 14 analogs were synthesized and investigated for FSH/LH stimulation and breast cancer inhibition. Analogs with single amino acid changes in positions 5-7 or 10 showed small or no difference in the FSH- or LH-releasing activity compared with GnRH-III but their anticancer potency decreased significantly. Modification of the terminal amino acids, side chain cyclization at the 6-8 regions, or combined amino acid changes at positions 4, 6 and/or 8 resulted in the decrease of both effects. Gonadotropin-releasing activity of Arg(8)-GnRH-III was improved 3-11-fold. A copolymer conjugate of GnRH-III showed 2-3-fold anticancer activity while losing endocrine potency. CONCLUSION The activation of GnRH-receptors on pituitary and breast cancer cells requires a specific structure and/or conformation that makes possible to improve the anticancer selectivity of GnRH analogs.
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Affiliation(s)
- Magdolna Kovács
- University of Pécs, Medical School, Department of Anatomy, Szigeti Str. 12, Pécs 7624, Hungary.
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Herédi-Szabó K, Murphy RF, Lovas S. Is lGnRH-III the most potent GnRH analog containing only natural amino acids that specifically inhibits the growth of human breast cancer cells? J Pept Sci 2007; 12:714-20. [PMID: 16967433 DOI: 10.1002/psc.783] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Analogs of the decapeptide, gonadotropin-releasing hormone (GnRH), used in the treatment of hormone-dependent tumors, contain numerous unnatural amino acids, giving rise to many adverse effects. lGnRH-III, a natural isoform of GnRH isolated from the sea lamprey, is a weak agonist of GnRH in the pituitary, but inhibits the growth of human cancer cells in micromolar concentrations. As lGnRH-III is not a natural ligand in humans, it is possible that a more potent peptide, also containing only natural amino acids, can be synthesized. A positional scanning peptide library, focused on the variable region of the GnRH family of peptides, residues 5-8, was synthesized. The synthesized peptides were analyzed in competitive binding experiments and six new analogs were designed on the basis of the results. Their biological activities were evaluated in cell growth experiments. The only natural sequence selected was chicken GnRH-II. The synthetic library did not yield a more potent peptide than lGnRH-III.
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Affiliation(s)
- Krisztina Herédi-Szabó
- Department of Biomedical Sciences, School of Medicine, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178-0405, USA
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Khan MAH, Prevost M, Waterston MM, Harvey MJA, Ferro VA. Effect of immunisation against gonadotrophin releasing hormone isoforms (mammalian GnRH-I, chicken GnRH-II and lamprey GnRH-III) on murine spermatogenesis. Vaccine 2006; 25:2051-63. [PMID: 17240004 DOI: 10.1016/j.vaccine.2006.11.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 11/16/2006] [Accepted: 11/16/2006] [Indexed: 10/23/2022]
Abstract
In mammals, the hypothalamic decapeptide, gonadotrophin releasing hormone (GnRH-I), is regarded as the major fertility regulating peptide. However, a range of isoforms also exists, varying only in the core region between amino acids 5-8. The physiological role of two of these, GnRH-II and GnRH-III, remains controversial, particularly with regard to fertility. The basis of the present study was to examine whether there is potential for GnRH-II and GnRH-III to be developed into highly specific vaccines, and to determine what the impact of their neutralisation would be on fertility. Computer modelling was used to predict how many common amino acids could be sequentially removed from the N-terminus, without loss of conformational structure. Sequences predicted to retain structure, were synthesised and conjugated to tetanus toxoid. Male mice were actively immunised, in study weeks 0, 2, 4 and 6 and peptide specific ELISA carried out. Mice immunised with TT-GnRH-I, TT-GnRH-II and TT-GnRH-III conjugates induced high antibody titres to the respective peptide. However, serum from TT-GnRH-I treated mice showed cross-reactivity to GnRH-II and GnRH-III peptides, and serum from TT-GnRH-II immunised mice showed cross-reactivity to GnRH-III. On the other hand, serum from only two of the TT-GnRH-III treated animals showed cross-reactivity to GnRH-II. Histological examination of the testes enabled comparative quantification of the disruption to spermatogenesis. Immunisation against TT-GnRH-I and TT-GnRH-III caused 66% and 68%, respectively, of seminiferous tubules viewed to show evidence of spermatogenesis, compared with 82% and 92% against TT-GnRH-II and untreated controls, respectively. Endocrine analysis revealed that only the TT-GnRH-I immunised animals showed significant reduction (p<0.05) in follicle stimulating hormone, while testosterone levels were reduced in the TT-GnRH-I and TT-GnRH-III treated animals. Taken together, our data suggests that GnRH-I and GnRH-III are implicated in spermatogenesis, unlike GnRH-II.
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Affiliation(s)
- Mohammad A H Khan
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Osaka 565 0871, Japan
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Bowen A, Khan S, Berghman L, Kirby JD, Wettemann RP, Vizcarra JA. Immunization of pigs against chicken gonadotropin-releasing hormone-II and lamprey gonadotropin-releasing hormone-III: Effects on gonadotropin secretion and testicular function1. J Anim Sci 2006; 84:2990-9. [PMID: 17032793 DOI: 10.2527/jas.2006-235] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective of this experiment was to evaluate the effects of active immunization against 2 GnRH isoforms on gonadotropin secretion and testicular function in pigs. Synthetic chicken (c) GnRH-II and lamprey (l) GnRH-III peptides, with the common pGlu-His-Trp-Ser sequence at the N-terminal omitted, were conjugated to BSA. Forty-eight male piglets were randomly assigned to 1 of 4 treatments. Pigs on treatment 1 were actively immunized against cGnRH-II, whereas pigs on treatment 2 were actively immunized against lGnRH-III. Control pigs on treatment 3 were actively immunized against the carrier protein (BSA), and pigs on treatment 4 were castrated and actively immunized against BSA. The BSA conjugate was emulsified in Freund's Incomplete Adjuvant and diethylaminoethyldextran. Primary immunization was given at 13 wk of age (WOA) with booster immunizations given at 16 and 19 WOA. Body weight and plasma samples were collected weekly beginning at 11 WOA. Treatments did not affect BW during the experimental period. Antibody titers were increased in animals immunized against cGnRH-II and lGnRH-III (P < 0.001). Cross-reactivity of the antibodies to mammalian GnRH or between cGnRH-II and lGnRH-III was minimal. Concentrations of testosterone were maximal in control boars (treatment 3) and minimal in control barrows (treatment 4) and immunized pigs (treatment x week; P < 0.01). Immunized animals had concentrations of LH (P < 0.001) and FSH (treatment x week; P < 0.03) that were less than control barrows and similar to control boars. At the end of the experiment, intact (noncastrated) pigs were exsanguinated. Testes were removed immediately; Leydig cells were isolated and treated with 0, 1, or 10 ng/mL of LH. There was an LH x GnRH treatment effect on testosterone concentrations (P < 0.03), indicating that Leydig cells were sensitive to the immunization protocol and doses of LH. Taken together, these data suggest that immunization against GnRH isoforms decreased gonadotropin secretion compared with control barrows. Additionally, immunization against cGnRH-II and lGnRH-III reduced the ability of Leydig cells to respond to LH challenges.
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Affiliation(s)
- A Bowen
- Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA
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Schneider F, Tomek W, Gründker C. Gonadotropin-releasing hormone (GnRH) and its natural analogues: a review. Theriogenology 2006; 66:691-709. [PMID: 16650469 DOI: 10.1016/j.theriogenology.2006.03.025] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Revised: 01/20/2006] [Accepted: 03/17/2006] [Indexed: 11/29/2022]
Abstract
The pivotal role of gonadotropin-releasing hormone (GnRH) during the hormonal regulation of reproductive processes is indisputable. Likewise, many factors are known to affect reproductive function by influencing either GnRH release from hypothalamus or pituitary gland responsiveness to GnRH. In veterinary medicine, GnRH and its agonists (GnRHa) are widely used to overcome reduced fertility by ovarian dysfunction, to induce ovulation, and to improve conception rate. GnRHa are, moreover, integrative part of other pro-fertility treatments, e.g. for synchronization of the estrous cycle or stimulation for embryo transfer. Additionally, continuous GnRH which shows desensitizing effects of the pituitary-ovarian axis has been recommended for implementation in anti-fertility treatments like inhibition of ovulation or reversible blockade of the estrous cycle. Just as much, another group of GnRH analogues, antagonists, are now in principle disposable for use. For a few decades, GnRH was thought to be a unique structure with a primary role in regulation gonadotropins. However, it became apparent that other homologous ligands of the GnRH receptor (GnRHR) exist. In the meantime, more than 20 natural variants of the mammalian GnRH have been identified in different species which may compete for binding and/or have their own receptors. These GnRH forms (GnRHs) have apparently common and divergent functions. More studies on GnRHs should contribute to a better understanding of reproductive processes in mammals and interactions between reproduction and other physiological functions. Increased information on GnRHs might raise expectations in the application of these peptides in veterinary practice. It is the aim of this review to discuss latest results from evolutionarily based studies as well as first experimental tests and to answer the question how realistic might be the efforts to develop effective and animal friendly practical applications for endogenous GnRHs and synthetic analogues.
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Affiliation(s)
- Falk Schneider
- Department of Reproductive Biology, Research Institute for the Biology of Farm Animals, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany.
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Kauffman AS, Rissman EF. Role of gonadotropin-releasing hormone II in the mammalian nervous system. Expert Rev Endocrinol Metab 2006; 1:133-145. [PMID: 30743776 DOI: 10.1586/17446651.1.1.133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) is a small neuropeptide of which there are multiple structural variants. The first variant identified in mammals, GnRH I, controls the release of pituitary gonadotropins. More recently, a second isoform, GnRH II, first isolated in the bird, was identified in the mammalian brain and periphery. Although it is unlikely to be a primary regulator of gonadotropin release, GnRH II appears to have a wide array of physiological and behavioral functions. GnRH II-containing fibers are present in several nuclei known to regulate reproduction and/or feeding, and its concentration in several of these areas fluctuates in response to changes in food availability, and thus energetic status. In musk shrews, GnRH II acts as a permissive regulator of female reproductive behavior based on energy status, as well as an inhibitor of short-term food intake. In this regard, GnRH II is similar to leptin, neuropeptide Y and several other neurotransmitters that regulate both feeding and reproduction. At least two GnRH receptors are present in the mammalian brain, and increasing evidence suggests that the behavioral effects of GnRH II are mediated by receptor subtypes distinct from the type-1 GnRH receptor (which mediates GnRH I action); the most probable candidate is the type-2 GnRH receptor. GnRH II also regulates the density and/or activity of calcium and potassium channels in the nervous systems of amphibians and fish, a function that may also exist in mammalian neurons. It is likely that the highly conserved GnRH II system has been co-opted over evolutionary time to possess multiple regulatory functions in a broad range of neurobiological aspects.
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Affiliation(s)
- Alexander S Kauffman
- a Department of Physiology and Biophysics, PO Box 356460, University of Washington, Seattle, WA 98195, USA.
| | - Emilie F Rissman
- b Department of Biochemistry and Molecular Genetics, University of Virginia, School of Medicine, PO Box 800733, 1300 Jefferson Park Avenue, Charlottesville, VA 22908, USA.
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Kauffold J, Schneider F, Zaremba W, Brüssow KP. Lamprey GnRH-III Stimulates FSH Secretion in Barrows. Reprod Domest Anim 2005; 40:475-9. [PMID: 16149955 DOI: 10.1111/j.1439-0531.2005.00609.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although studies have indicated that follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release can be dissociated in the pig, the underlying mechanisms are still to be answered. Since it was demonstrated that lamprey gonadotropin-releasing hormone (l-GnRH-III) has preferential FSH-releasing potency in several mammalian species, we have investigated the gonadotropin-releasing activity of l-GnRH-III in barrows. Each of nine barrows (body weight: 85-90 kg; age: 207 days) received 2 ml saline (S-barrow), followed by 150 microg l-GnRH-III (1.6-1.7 microg/kg body weight) dissolved in 2 ml saline intramuscularly 7 days later. Three pre-treatment and 13 post-treatment blood samples were taken at intervals of 30 min to 8 h to assess basal and treatment-associated concentrations of FSH and LH, respectively, by radioimmunoassay. Animals were defined as having responded to treatment if, 2 h post-treatment, plasma FSH and/or LH levels were >3 SD of the respective basal concentrations. There was no treatment-associated FSH response after saline treatment, but a clear FSH response in all l-GnRH-III-injected barrows. On average, the maximum FSH level (205% of the basal concentration) was observed at 1 h post-treatment. Mean FSH values were elevated until 10 h post-treatment. There was no LH response either to saline or to l-GnRH-III. In conclusion, this study demonstrates a selective FSH-releasing activity of 150 microg l-GnRH-III in barrows. Further studies are needed to investigate whether this effect is ubiquitous in the pig and what the physiological relevance is.
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Affiliation(s)
- J Kauffold
- Large Animal Clinic for Theriogenology and Ambulatory Services, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany.
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Parhar IS, Soga T, Ogawa S, Ogawa S, Pfaff DW, Sakuma Y. Nonmammalian gonadotropin-releasing hormone molecules in the brain of promoter transgenic rats. Proc Natl Acad Sci U S A 2005; 102:5880-5. [PMID: 15824321 PMCID: PMC556124 DOI: 10.1073/pnas.0501832102] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mammalian gonadotropin-releasing hormone (GnRH1) and nonmammalian immunoreactive GnRH subtypes were examined in transgenic rats carrying an enhanced GFP (EGFP) reporter gene driven by a rat GnRH1 promoter. Double-label immunocytochemistry was performed on EGFP(+)/GnRH1 brain sections by using antisera against GnRH1, GnRH2 (chicken II), GnRH3 (salmon), or seabream GnRH. EGFP(+)/GnRH1 neurons were in the septal-preoptic hypothalamus but not in the midbrain, consistent with GnRH1-immunopositive neurons in WT rats. Apparent coexpression of EGFP(+)/GnRH1 with other GnRH subtypes was observed. All EGFP(+) neurons in the septal-preoptic hypothalamus were GnRH1-immunopositive. However, only approximately 80% of GnRH1-immunopositive neurons were EGFP(+), which awaits further elucidation. GnRH subtypes-immunopositive fibers and EGFP(+)/GnRH1 fibers were conspicuous in the organum vasculosum of the lamina terminalis, median eminence, and surrounding the ependymal walls of the third ventricle and the aqueduct in the midbrain. These results demonstrate that the expression of the EGFP-GnRH1 transgene is restricted to the bona fide GnRH1 population and provide clear morphological evidence supporting the existence of GnRH1 neuronal subpopulations in the septal-preoptic hypothalamus, which might be driven by different segments of the GnRH promoter. This genetic construct permits analyses of promoter usage in GnRH neurons, and our histochemical approaches open questions about functional relations among isoforms of this peptide, which regulates reproductive physiology in its behavioral and endocrine aspects.
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Affiliation(s)
- Ishwar S Parhar
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan.
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Herédi-Szabó K, Lubke J, Toth G, Murphy RF, Lovas S. Importance of the central region of lamprey gonadotropin-releasing hormone III in the inhibition of breast cancer cell growth. Peptides 2005; 26:419-22. [PMID: 15652648 DOI: 10.1016/j.peptides.2004.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Revised: 10/06/2004] [Accepted: 10/08/2004] [Indexed: 10/26/2022]
Abstract
Naturally occurring isoforms of the decapeptide gonadotropin-releasing hormone (GnRH) share residues 1-4 and 9-10. lGnRH-III, the third isoform isolated in the sea lamprey has no endocrine effect in mammals but shows a direct antiproliferative effect on human breast, prostate and endometrial cancer cell lines. To investigate these features, residues 5-8 of lGnRH-III were systematically replaced with Ala. The ability of the synthetic analogs to interact with receptors on MDA-MB 231 human breast cancer cells and their effect on the growth of the same cell line were investigated. [Ala6]lGnRH-III and [Ala7]lGnRH-III have neither receptor binding nor antiproliferative activity. Replacement of His5 with Ala resulted in an analog that binds to the receptor but does not have antiproliferative activity. The results are in agreement with previous reports that modifications of Lys at position 8 are well tolerated.
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Affiliation(s)
- Krisztina Herédi-Szabó
- Department of Biomedical Sciences, School of Medicine, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178-0405, USA
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Amstalden M, Zieba DA, Garcia MR, Stanko RL, Welsh TH, Hansel WH, Williams GL. Evidence that lamprey GnRH-III does not release FSH selectively in cattle. Reproduction 2004; 127:35-43. [PMID: 15056768 DOI: 10.1530/rep.1.00022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Experiments were performed to test the hypothesis that lamprey GnRH-III (lGnRH-III) selectively releases FSH. Primary cultures of bovine adenohypophyseal cells were treated with mammalian GnRH (mGnRH) and lGnRH-III (10−9, 10−8, 10−7 and 10−6 M) or control media in Experiment 1. All doses of mGnRH and the two highest doses of lGnRH-III stimulated (P < 0.001) a non-selective release of LH and FSH. In Experiments 2–4, Latin Square designs were utilized in vivo to examine whether physiological and hormonal milieu regulate putative selective effects of lGnRH-III. In Experiments 2 and 3, ovariectomized cows with basal levels of estradiol only (Experiment 2) or in combination with luteal phase levels of progester-one (Experiment 3) were injected with mGnRH and lGnRH-III (0.055, 0.11, 0.165 and 1.1 μg/kg body weight (BW) and saline. All doses of mGnRH released (P < 0.001) LH and FSH, but only the highest dose of lGnRH-III stimulated (P < 0.001) a non-selective release of both LH and FSH (Experiment 3). For Experiments 4A and 4B, intact, mid-luteal phase cows were injected with mGnRH and lGnRH-III (1.1 μg/kg BW; Experiment 4A), lGnRH-III (1.1 and 4.4 μg/kg BW; Experiment 4B) and saline. As before, mGnRH released (P < 0.001) both LH and FSH at all doses. In contrast, lGnRH-III at the highest dose released (P < 0.001) LH but not FSH. These findings suggest that lGnRH-III may act as a weak competitor for the mGnRH receptor and do not support the hypothesis that it selectively releases FSH in cattle.
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Affiliation(s)
- M Amstalden
- Animal Reproduction Laboratory, Texas A&M University Agricultural Research Station, Beeville, Texas 78102, USA
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