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Szabo Z, Juhasz E, Schally AV, Dezso B, Huga S, Hernadi Z, Halmos G, Kiss C. Expression of Growth Hormone-Releasing Hormone and Its Receptor Splice Variants in Primary Human Endometrial Carcinomas: Novel Therapeutic Approaches. Molecules 2022; 27:molecules27092671. [PMID: 35566020 PMCID: PMC9101386 DOI: 10.3390/molecules27092671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 11/16/2022]
Abstract
Antagonists of growth hormone-releasing hormone (GHRH) inhibit the growth of various tumors, including endometrial carcinomas (EC). However, tumoral receptors that mediate the antiproliferative effects of GHRH antagonists in human ECs have not been fully characterized. In this study, we investigated the expression of mRNA for GHRH and splice variants (SVs) of GHRH receptors (GHRH-R) in 39 human ECs and in 7 normal endometrial tissue samples using RT-PCR. Primers designed for the PCR amplification of mRNA for the full length GHRH-R and SVs were utilized. The PCR products were sequenced, and their specificity was confirmed. Nine ECs cancers (23%) expressed mRNA for SV1, three (7.7%) showed SV2 and eight (20.5%) revealed mRNA for SV4. The presence of SVs for GHRH-Rs could not be detected in any of the normal endometrial tissue specimens. The presence of specific, high affinity GHRH-Rs was also demonstrated in EC specimens using radioligand binding studies. Twenty-four of the investigated thirty-nine tumor samples (61.5%) and three of the seven corresponding normal endometrial tissues (42.9%) expressed mRNA for GHRH ligand. Our findings suggest the possible existence of an autocrine loop in EC based on GHRH and its tumoral SV receptors. The antiproliferative effects of GHRH antagonists on EC are likely to be exerted in part by the local SVs and GHRH system.
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Affiliation(s)
- Zsuzsanna Szabo
- Department of Biopharmacy, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (G.H.)
| | - Eva Juhasz
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
| | - Andrew V. Schally
- Veterans Affairs Medical Center, Endocrine, Polypeptide and Cancer Institute, Miami, FL 33125, USA;
- Department of Pathology, Department of Medicine, Divisions of Hematology-Oncology and Endocrinology, Miller School of Medicine, University of Miami, Miami, FL 33101, USA
- Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL 33136, USA
| | - Balazs Dezso
- Department of Pathology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
| | - Sandor Huga
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (S.H.); (Z.H.)
| | - Zoltan Hernadi
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (S.H.); (Z.H.)
| | - Gabor Halmos
- Department of Biopharmacy, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (G.H.)
- Veterans Affairs Medical Center, Endocrine, Polypeptide and Cancer Institute, Miami, FL 33125, USA;
| | - Csongor Kiss
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
- Correspondence: ; Tel.: +36-52-452-747; Fax: +36-52-255-893
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Xiong X, Ke X, Wang L, Yao Z, Guo Y, Zhang X, Chen Y, Pang CP, Schally AV, Zhang H. Splice variant of growth hormone-releasing hormone receptor drives esophageal squamous cell carcinoma conferring a therapeutic target. Proc Natl Acad Sci U S A 2020; 117:6726-32. [PMID: 32156725 DOI: 10.1073/pnas.1913433117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
An explanation has been lacking for the suppressive action of antagonists of growth hormone-releasing hormone receptors (GHRH-Rs) on cancers that do not express GHRH-Rs, an established target of the antagonists. We demonstrate here that esophageal squamous cell carcinoma (ESCC), a representative cancer type that barely expresses GHRH-Rs, responds to GHRH-R antagonists. Hypoxia induces GHRH-R splice variant 1 (SV1) and activates a key glycolytic enzyme. Glycolytic metabolism and tumor progression are promoted by activation of SV1 and reversed by the GHRH-R antagonist MIA-602. A high expression of SV1 in ESCC patients predicts a poor prognosis. These findings document the importance of SV1 as a target of GHRH-R antagonists and underline the therapeutic potential of GHRH-R antagonists against SV1-expressing cancers. The extrahypothalamic growth hormone-releasing hormone (GHRH) and its cognate receptors (GHRH-Rs) and splice variants are expressed in a variety of cancers. It has been shown that the pituitary type of GHRH-R (pGHRH-R) mediates the inhibition of tumor growth induced by GHRH-R antagonists. However, GHRH-R antagonists can also suppress some cancers that do not express pGHRH-R, yet the underlying mechanisms have not been determined. Here, using human esophageal squamous cell carcinoma (ESCC) as a model, we were able to reveal that SV1, a known splice variant of GHRH-R, is responsible for the inhibition induced by GHRH-R antagonist MIA-602. We demonstrated that GHRH-R splice variant 1 (SV1) is a hypoxia-driven promoter of tumor progression. Hypoxia-elevated SV1 activates a key glycolytic enzyme, muscle-type phosphofructokinase (PFKM), through the nuclear factor kappa B (NF-κB) pathway, which enhances glycolytic metabolism and promotes progression of ESCC. The malignant actions induced by the SV1–NF-κB–PFKM pathway could be reversed by MIA-602. Altogether, our studies demonstrate a mechanism by which GHRH-R antagonists target SV1. Our findings suggest that SV1 is a hypoxia-induced oncogenic promoter which can be an alternative target of GHRH-R antagonists.
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Jimenez JJ, DelCanto GM, Popovics P, Perez A, Vila Granda A, Vidaurre I, Cai RZ, Rick FG, Swords RT, Schally AV. A new approach to the treatment of acute myeloid leukaemia targeting the receptor for growth hormone-releasing hormone. Br J Haematol 2018; 181:476-485. [PMID: 29663325 DOI: 10.1111/bjh.15207] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/22/2018] [Indexed: 11/30/2022]
Abstract
Growth hormone-releasing hormone (GHRH) is secreted by the hypothalamus and acts on the pituitary gland to stimulate the release of growth hormone (GH). GHRH can also be produced by human cancers, in which it functions as an autocrine/paracrine growth factor. We have previously shown that synthetic antagonistic analogues of GHRH are able to successfully suppress the growth of 60 different human cancer cell lines representing over 20 cancers. Nevertheless, the expression of GHRH and its receptors in leukaemias has never been examined. Our study demonstrates the presence of GHRH receptor (GHRH-R) on 3 of 4 human acute myeloid leukaemia (AML) cell lines-K-562, THP-1, and KG-1a-and significant inhibition of proliferation of these three cell lines in vitro following incubation with the GHRH antagonist MIA-602. We further show that this inhibition of proliferation is associated with the upregulation of pro-apoptotic genes and inhibition of Akt signalling in leukaemic cells. Treatment with MIA-602 of mice bearing xenografts of these human AML cell lines drastically reduced tumour growth. The expression of GHRH-R was further confirmed in 9 of 9 samples from patients with AML. These findings offer a new therapeutic approach to this malignancy and suggest a possible role of GHRH-R signalling in the pathology of AML.
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Affiliation(s)
- Joaquin J Jimenez
- Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA.,Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Gina M DelCanto
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Petra Popovics
- Division of Endocrinology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.,Veterans Affairs Medical Center, Miami, FL, USA
| | - Aymee Perez
- Sylvester Comprehensive Cancer Center, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Ailin Vila Granda
- Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | | | - Ren-Zhi Cai
- Division of Endocrinology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.,Veterans Affairs Medical Center, Miami, FL, USA
| | - Ferenc G Rick
- Veterans Affairs Medical Center, Miami, FL, USA.,Department of Urology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Ronan T Swords
- Sylvester Comprehensive Cancer Center, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.,Division of Hematology/Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Andrew V Schally
- Division of Endocrinology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.,Veterans Affairs Medical Center, Miami, FL, USA.,Sylvester Comprehensive Cancer Center, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.,Division of Hematology/Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.,Department of Pathology, Miller School of Medicine, University of Miami, Miami, FL, USA
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Muñoz-Moreno L, Arenas MI, Carmena MJ, Schally AV, Sánchez-Chapado M, Prieto JC, Bajo AM. Anti-proliferative and pro-apoptotic effects of GHRH antagonists in prostate cancer. Oncotarget 2016; 7:52195-206. [PMID: 27448980 DOI: 10.18632/oncotarget.10710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 06/16/2016] [Indexed: 12/17/2022] Open
Abstract
Growth hormone-releasing hormone (GHRH) and its receptors have been implicated in the progression of various tumors. In vitro and in vivo studies have demonstrated that GHRH antagonists inhibit the growth of several cancers. GHRH antagonists, JMR-132 and JV-1-38 inhibit the growth of androgen-independent prostate tumors. Here we investigated the involvement of GHRH antagonists in proliferative and apoptotic processes. We used non-tumoral RWPE-1 and tumoral LNCaP and PC3 human prostatic epithelial cells, as well as an experimental model of human tumor PC3 cells. We evaluated the effects of JMR-132 and JV-1-38 antagonists on cell viability and proliferation in the three cell lines by means of MTT and BrdU assays, respectively, as well as on cell cycle and apoptotic process in PC3 cells. The expression levels of PCNA, p53, p21, CD44, Cyclin D1, c-myc, Bax and Bcl2 were determined in both in vivo and in vitro models by means of Western-blot and RT-PCR. GHRH antagonists suppressed cell proliferation and decreased the levels of the proliferation marker, PCNA, in the three cell lines and in PC3 tumor. GHRH antagonists led to an increase of cells in S-phase and a decrease in G1 and G2/M phases, and induced S-phase arrest and increase of apoptotic cells. The effects of GHRH-antagonists on cell cycle could be due to the changes observed in the expression of p21, p53, Bax, Bcl2, CD44, Cyclin D1, c-myc and caspase 3. Present results confirm and extend the role of GHRH antagonists as anti-proliferative and pro-apoptotic molecules in prostate cancer.
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Abstract
Neuroendocrine tumors (NETs) are a very heterogeneous group that are thought to originate from the cells of the endocrine and nervous systems. These tumors develop in a number of organs, predominantly in the gastrointestinal and pulmonary systems. Clinical detection and diagnosis are reliable at the late stages when metastatic spread has occurred. However, traditional conventional therapies such as radiation and chemotherapy are not effective. In the majority of cases even surgical resection at that stage is unlikely to produce promising reusults. NETs present a serious clinical challenge, as the survival rates remain low, and as these rare tumors are very difficult to study, novel approaches and therapies are required. This review will highlight the important points of accumulated knowledge covering the molecular aspects of the role of neuroendocrine cells, hormonal peptides, the reasons for ectopic hormone production in NET, neuropeptides and epigenetic regulation as well as the other challenging questions that require further understanding.
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Affiliation(s)
- Parthik Patel
- Department of Orthopedic Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Karina Galoian
- Department of Orthopedic Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Moscona JC, Peters MN, Schally AV, Srivastav S, Delafontaine P, Irimpen A. The effects of a growth hormone-releasing hormone antagonist and a gastrin-releasing peptide antagonist on intimal hyperplasia of the carotid artery after balloon injury in a diabetic rat model☆. Artery Res 2017. [DOI: 10.1016/j.artres.2017.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Abstract
It is a pleasure to contribute our presentation at the International Prostate Forum of the Annual Meeting of the American Urological Association (AUA) to this special issue of the Asian Journal of Andrology.
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Affiliation(s)
- Andrew V Schally
- Veterans Affairs Medical Center and South Florida Veterans Affairs Foundation for Research and Education, Miami, FL 33125; Department of Pathology; Department of Medicine, Division of Hematology/Oncology; Department of Medicine, Division of Endocrinology; Department of Medicine, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Szepeshazi K, Block NL, Schally AV. The use of peptide analogs for the treatment of gastrointestinal, pancreatic, liver and urinary bladder cancers. Horm Mol Biol Clin Investig 2015; 1:103-10. [PMID: 25961976 DOI: 10.1515/hmbci.2010.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 11/02/2009] [Indexed: 12/15/2022]
Abstract
Peptide hormones can influence the development and growth of many cancers which are not considered classical hormone-dependent tumors. Analogs of somatostatin, bombesin/gastrin-releasing peptide (GRP), luteinizing hormone-releasing hormone (LH-RH) and growth hormone-releasing hormone (GH-RH) can interfere with receptors on tumor cells or intracellular pathways that are important in cell proliferation and in this way inhibit tumor growth. The first part of this review explains how these peptide hormones and their analogs affect tumors. The second part of this review describes how various hormone analogs can be used for the treatment of gastric, colorectal, pancreatic, liver and urinary bladder cancers. These tumors are major health problems worldwide and their treatment remains a great challenge. Receptors for somatostatin, bombesin/GRP, LH-RH and GH-RH are present in a large percentage of these cancers. We have developed a series of cytotoxic peptides based on doxorubicin or its derivative 2-pyrrolino-doxorubicin coupled to an analog of LH-RH, somatostatin or bombesin. This new class of targeted analogs might provide a more effective therapy for various cancers that express receptors for these carrier peptides, while producing significantly reduced peripheral toxicity. Under experimental conditions, these peptide hormone analogs strongly inhibited the growth of these tumors. Cytotoxic analogs were particularly effective on tumors that express the specific peptide receptors and acted more powerfully than the carrier peptide or the cytotoxic compound alone. Clinical trials on these peptide analogs are in progress.
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Subramani R, Lopez-Valdez R, Salcido A, Boopalan T, Arumugam A, Nandy S, Lakshmanaswamy R. Growth hormone receptor inhibition decreases the growth and metastasis of pancreatic ductal adenocarcinoma. Exp Mol Med 2014; 46:e117. [PMID: 25301264 DOI: 10.1038/emm.2014.61] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/12/2014] [Accepted: 07/31/2014] [Indexed: 12/19/2022] Open
Abstract
Pancreatic cancer is the only major cancer with very low survival rates (1%). It is the fourth leading cause of cancer-related death. Hyperactivated growth hormone receptor (GHR) levels have been shown to increase the risk of cancer in general and this pathway is a master regulator of key cellular functions like proliferation, apoptosis, differentiation, metastasis, etc. However, to date there is no available data on how GHR promotes pancreatic cancer pathogenesis. Here, we used an RNA interference approach targeted to GHR to determine whether targeting GHR is an effective method for controlling pancreatic cancer growth and metastasis. For this, we used an in vitro model system consisting of HPAC and PANC-1 pancreatic cancer cells lines. GHR is upregulated in both of these cell lines and silencing GHR significantly reduced cell proliferation and viability. Inhibition of GHR also reduced the metastatic potential of pancreatic cancer cells, which was aided through decreased colony-forming ability and reduced invasiveness. Flow cytometric and western blot analyses revealed the induction of apoptosis in GHR silenced cells. GHR silencing affected phosphatidylinositol 3 kinase/AKT, mitogen extracellular signal-regulated kinase/extracellular signal-regulated kinase, Janus kinase/signal transducers and activators of transcription and mammalian target of rapamycin signaling, as well as, epithelial to mesenchymal transition. Interestingly, silencing GHR also suppressed the expression of insulin receptor-β and cyclo-oxygenease-2. Altogether, GHR silencing controls the growth and metastasis of pancreatic cancer and reveals its importance in pancreatic cancer pathogenesis.
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Mezey G, Treszl A, Schally AV, Block NL, Vízkeleti L, Juhász A, Klekner Á, Nagy J, Balázs M, Halmos G, Bognár L. Prognosis in human glioblastoma based on expression of ligand growth hormone-releasing hormone, pituitary-type growth hormone-releasing hormone receptor, its splicing variant receptors, EGF receptor and PTEN genes. J Cancer Res Clin Oncol 2014; 140:1641-9. [DOI: 10.1007/s00432-014-1716-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 05/14/2014] [Indexed: 12/13/2022]
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Abstract
The aim of the current study is to investigate the effects of growth hormone releasing hormone (GHRH) antagonist on acetaminophen (APAP)-induced acute liver injury in mice. Healthy C57/B6L mice were orally treated with 200 mg/kg APAP with or without a 30-min pre-treatment with 300 µg/kg GHRH antagonist MZ-5-156. After 12 hours, serum, plasma, and liver samples from each mouse were collected for analyses. Our results showed that twelve-hour treatment with APAP caused obvious liver injury, elevated serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, increased oxidative stress, reduced expressions of antioxidant enzymes, accumulated expression of pro-inflammatory cytokines, and increased circulating levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I). Pre-treatment with MZ-5-156 aggravated liver injury, further increased serum ALT and AST levels, exacerbated oxidative stress and inflammation induced by APAP. Treatment of MZ-5-156 also blocked the phosphorylation form and total form of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5). Treatment of GHRH super-agonist JI-38 immediately after MZ-5-156 treatment partly reversed the liver injury caused by APAP and MZ-5-156. In conclusion, GHRH plays essential protective role in APAP-induced acute liver injury in vivo. The protective properties of GHRH are partially through GH/IGF-I axis and JAK/STAT pathway.
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Affiliation(s)
- Tao Wang
- First affiliated hospital, Xinxiang Medical University, Henan, China
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Pozsgai E, Schally AV, Zarandi M, Varga JL, Vidaurre I, Bellyei S. The effect of GHRH antagonists on human glioblastomas and their mechanism of action. Int J Cancer 2010; 127:2313-22. [PMID: 20162575 DOI: 10.1002/ijc.25259] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of new growth hormone-releasing hormone (GHRH) antagonists JMR-132 and MIA-602 and their mechanism of action were investigated on 2 human glioblastoma cell lines, DBTRG-05 and U-87MG, in vitro and in vivo. GHRH receptors and their main splice variant, SV1 were found on both cell lines. After treatment with JMR-132 or MIA-602, the cell viability decreased significantly. A major decrease in the levels of phospho-Akt, phospho-GSK3β and phosho-ERK 1/2 was detected at 5 and 10 min following treatment with the GHRH antagonists, whereas elevated levels of phospho-p38 were observed at 24 hr. The expression of caspase-3 and poly(ADP-ribose) (PARP), as the downstream executioners of apoptosis were found to be significantly elevated after treatment. Following treatment of the glioblastoma cells with GHRH antagonists, nuclear translocation of apoptosis inducing factor (AIF) and Endonuclease G (Endo G) and the mitochondrial release of cytochrome c (cyt c) were detected, indicating that the cells were undergoing apoptosis. In cells treated with GHRH antagonists, the collapse of the mitochondrial membrane potential was shown with fluorescence microscopy and JC-1 membrane potential sensitive dye. There were no significant differences between results obtained in DBTRG-05 or U-87MG cell lines. After treatment with MIA-602 and JMR-132, the reduction rate in the growth of DBTRG-05 glioblastoma, xenografted into nude mice, was significant and tumor doubling time was also significantly extended when compared with controls. Our study demonstrates that GHRH antagonists induce apoptosis through key proapoptotic pathways and shows the efficacy of MIA-602 for experimental treatment of glioblastoma.
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Affiliation(s)
- Eva Pozsgai
- Veterans Affairs Medical Center and South Florida Veterans Affairs Foundation for Research and Education, Miami, FL 33125, USA
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Annunziata M, Grande C, Scarlatti F, Deltetto F, Delpiano E, Camanni M, Ghigo E, Granata R. The growth hormone–releasing hormone (GHRH) antagonist JV-1-36 inhibits proliferation and survival of human ectopic endometriotic stromal cells (ESCs) and the T HESC cell line. Fertil Steril 2010; 94:841-9. [DOI: 10.1016/j.fertnstert.2009.03.093] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 03/24/2009] [Accepted: 03/26/2009] [Indexed: 11/25/2022]
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Guo J, Schally AV, Zarandi M, Varga J, Leung PCK. Antiproliferative effect of growth hormone-releasing hormone (GHRH) antagonist on ovarian cancer cells through the EGFR-Akt pathway. Reprod Biol Endocrinol 2010; 8:54. [PMID: 20509930 PMCID: PMC2891788 DOI: 10.1186/1477-7827-8-54] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 05/28/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Antagonists of growth hormone-releasing hormone (GHRH) are being developed for the treatment of various human cancers. METHODS MTT assay was used to test the proliferation of SKOV3 and CaOV3. The splice variant expression of GHRH receptors was examined by RT-PCR. The expression of protein in signal pathway was examined by Western blotting. siRNA was used to block the effect of EGFR. RESULTS In this study, we investigated the effects of a new GHRH antagonist JMR-132, in ovarian cancer cell lines SKOV3 and CaOV3 expressing splice variant (SV)1 of GHRH receptors. MTT assay showed that JMR-132 had strong antiproliferative effects on SKOV3 and CaOV3 cells in both a time-dependent and dose-dependent fashion. JMR-132 also induced the activation and increased cleaved caspase3 in a time- and dose-dependent manner in both cell lines. In addition, JMR-132 treatments decreased significantly the epidermal growth factor receptor (EGFR) level and the phosphorylation of Akt (p-Akt), suggesting that JMR-132 inhibits the EGFR-Akt pathway in ovarian cancer cells. More importantly, treatment of SKOV3 and CaOV3 cells with 100 nM JMR-132 attenuated proliferation and the antiapoptotic effect induced by EGF in both cell lines. After the knockdown of the expression of EGFR by siRNA, the antiproliferative effect of JMR-132 was abolished in SKOV3 and CaOV3 cells. CONCLUSIONS The present study demonstrates that the inhibitory effect of the GHRH antagonist JMR-132 on proliferation is due, in part, to an interference with the EGFR-Akt pathway in ovarian cancer cells.
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Affiliation(s)
- Jian Guo
- Department of Obstetrics & Gynaecology, Child and Family Research Institute, UBC, Vancouver, Canada
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Andrew V Schally
- Veterans Affairs Medical Center and Departments of Pathology and Medicine, Division of Hematology/Oncology, University of Miami Miller School of Medicine, Miami, FL 33125, USA
| | - Marta Zarandi
- Veterans Affairs Medical Center and Departments of Pathology and Medicine, Division of Hematology/Oncology, University of Miami Miller School of Medicine, Miami, FL 33125, USA
| | - Jozsef Varga
- Veterans Affairs Medical Center and Departments of Pathology and Medicine, Division of Hematology/Oncology, University of Miami Miller School of Medicine, Miami, FL 33125, USA
| | - Peter CK Leung
- Department of Obstetrics & Gynaecology, Child and Family Research Institute, UBC, Vancouver, Canada
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Bellyei S, Schally AV, Zarandi M, Varga JL, Vidaurre I, Pozsgai E. GHRH antagonists reduce the invasive and metastatic potential of human cancer cell lines in vitro. Cancer Lett 2010; 293:31-40. [PMID: 20064686 DOI: 10.1016/j.canlet.2009.12.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Revised: 12/13/2009] [Accepted: 12/17/2009] [Indexed: 12/21/2022]
Abstract
We investigated the effect of a GHRH antagonist, MIA-602on the metastatic cascade in vitro of three human cancers, DBTRG-05 glioblastoma, MDA-MB-468 estrogen-independent breast, and ES-2 clear cell ovarian cancer. GHRH receptors and their main splice variant, SV1 were detected on all three cell lines. After treatment with MIA-602, the cell viability decreased significantly, significant inhibition of cell invasion was observed and the release of MMPs was significantly decreased. The attachment of cancer cells to fibronectin and matrigel was severely hindered. Wound-healing experiments demonstrated a reduced cellular motility in all three cell lines. The upregulation of caveolin-1 and E-cadherin,and thepowerful downregulation of NF-kappaB and beta-catenin was detected. Our study suggests that the clinical application of highly potent GHRH antagonists in cancer therapy would be desirable since they inhibit proliferation and metastasis development as well.
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Köster F, Engel JB, Schally AV, Hönig A, Schröer A, Seitz S, Hohla F, Ortmann O, Diedrich K, Buchholz S. Triple-negative breast cancers express receptors for growth hormone-releasing hormone (GHRH) and respond to GHRH antagonists with growth inhibition. Breast Cancer Res Treat 2008; 116:273-9. [DOI: 10.1007/s10549-008-0120-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 07/01/2008] [Indexed: 11/24/2022]
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Schally AV, Varga JL, Engel JB. Antagonists of growth-hormone-releasing hormone: an emerging new therapy for cancer. ACTA ACUST UNITED AC 2008; 4:33-43. [PMID: 18084344 DOI: 10.1038/ncpendmet0677] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Accepted: 10/01/2007] [Indexed: 12/28/2022]
Abstract
This article reviews the potential clinical uses of antagonists of growth-hormone-releasing hormone (GHRH) for tumor therapy. GHRH antagonists suppress the growth of various human cancer lines xenografted into nude mice; such tumors include breast, ovarian, endometrial and prostate cancers, lung cancers (small-cell lung carcinomas and non-small-cell lung carcinomas), renal, pancreatic, gastric and colorectal carcinomas, brain tumors (malignant gliomas), osteogenic sarcomas and non-Hodgkin's lymphomas. The antitumor effects of GHRH antagonists are exerted in part indirectly through the inhibition of the secretion of GH from the pituitary and the resulting reduction in the levels of hepatic insulin-like growth factor I (IGF-I). The main effects of the GHRH antagonists are, however, exerted directly on tumors. GHRH ligand is present in various human cancers and might function as an autocrine and/or paracrine growth factor. Pituitary-type GHRH receptors and their splice variants are also found in many human cancers. The inhibitory effects of GHRH antagonists seem to be due to the blockade of action of tumoral GHRH. Antagonists of GHRH can also suppress cancer growth by blocking production of IGF-I and/or IGF-II by the tumor. Further development of GHRH antagonists that are still-more potent should lead to potential therapeutic agents for various cancers.
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Buchholz S, Schally AV, Engel JB, Hohla F, Heinrich E, Koester F, Varga JL, Halmos G. Potentiation of mammary cancer inhibition by combination of antagonists of growth hormone-releasing hormone with docetaxel. Proc Natl Acad Sci U S A 2007; 104:1943-6. [PMID: 17261802 PMCID: PMC1794297 DOI: 10.1073/pnas.0610860104] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antagonists of growth hormone-releasing hormone (GHRH) are being developed for the treatment of various cancers. In this study, we investigated the effectiveness of treatment with GHRH antagonist JMR-132 alone and in combination with docetaxel chemotherapy in nude mice bearing MX-1 human breast cancers. Specific high-affinity binding sites for GHRH were found on MX-1 tumor membranes using ligand competition assays with (125)I-labeled GHRH antagonist JV-1-42. JMR-132 displaced radiolabeled JV-1-42 with an IC(50) of 0.14 nM, indicating a high affinity of JMR-132 to GHRH receptors. Treatment of nude mice bearing xenografts of MX-1 with JMR-132 at 10 microg per day s.c. for 22 days significantly (P < 0.05) inhibited tumor volume by 62.9% and tumor weight by 47.8%. Docetaxel given twice at a dose of 20 mg/kg i.p. significantly reduced tumor volume and weight by 74.1% and 58.6%, respectively. Combination treatment with JMR-132 (10 microg/day) and docetaxel (20 mg/kg i.p.) led to growth arrest of most tumors as shown by an inhibition of tumor volume and weight by 97.7% and 95.6%, respectively (P < 0.001). Because no vital cancer cells were detected in some of the excised tumors, a total regression of the tumors was achieved in some cases. Treatment with JMR-132 also strongly reduced the concentration of EGF receptors in MX-1 tumors. Our results demonstrate that GHRH antagonists might provide a therapy for breast cancer and could be combined with docetaxel chemotherapy to enhance the efficacy of treatment.
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Affiliation(s)
- Stefan Buchholz
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
- Klinik und Poliklinik für Frauenheilkunde und Geburtshilfe, Universität Regensburg, 93051 Regensbug, Germany
| | - Andrew V. Schally
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
- Veterans Affairs Medical Center, South Florida Veterans Affairs Foundation for Research and Education, Miami, FL 33125
- University of Miami Miller School of Medicine, Miami, FL 33101
- To whom correspondence should be addressed at:
VA Medical Center, 1201 Northwest 16th Street, Research (151), Room 2A103C, Miami, FL 33125. E-mail:
| | - Jörg B. Engel
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
- Universität Würzburg, Frauenklinik, 97080 Würzburg, Germany; and
| | - Florian Hohla
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
- **Department of Internal Medicine, Hospital Oberndorf, 5100 Oberndorf, Austria
| | - Elmar Heinrich
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Frank Koester
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Jozsef L. Varga
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Gabor Halmos
- *Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112
- Veterans Affairs Medical Center, South Florida Veterans Affairs Foundation for Research and Education, Miami, FL 33125
- University of Miami Miller School of Medicine, Miami, FL 33101
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Havt A, Schally AV, Halmos G, Varga JL, Toller GL, Horvath JE, Szepeshazi K, Köster F, Kovitz K, Groot K, Zarandi M, Kanashiro CA. The expression of the pituitary growth hormone-releasing hormone receptor and its splice variants in normal and neoplastic human tissues. Proc Natl Acad Sci U S A 2005; 102:17424-9. [PMID: 16299104 PMCID: PMC1297670 DOI: 10.1073/pnas.0506844102] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Various attempts to detect human pituitary growth hormone-releasing hormone receptor (pGHRH-R) in neoplastic extrapituitary tissues have thus far failed. Recently, four splice variants (SVs) of GHRH-R have been described, of which SV1 has the highest structural homology to pGHRH-R and likely plays a role in tumor growth. The aim of this study was to reinvestigate whether human tumors and normal human extrapituitary tissues express the pGHRH-R and to corroborate our previous findings on its SVs. Thus, we developed a real-time PCR method for the detection of the mRNA for the pGHRH-R, its SVs, and the GHRH peptide. Using real-time PCR, Western blotting, and radioligand-binding assays, we detected the mRNA for pGHRH-R and pGHRH-R protein in various human cancer cell lines grown in nude mice and in surgical specimens of human lung cancers. The expression of mRNA for SVs of pGHRH-R and GHRH was likewise found in xenografts of human non-Hodgkin's lymphomas, pancreatic cancer, glioblastoma, small-cell lung carcinomas, and in human nonmalignant prostate, liver, lung, kidney, and pituitary. Western blots showed that these normal and malignant human tissues contain SV1 protein and immunoreactive GHRH. Our results demonstrate that some normal human tissues and tumors express mRNA and protein for the pGHRH-R and its splice variants. These findings confirm and extend the concept that GHRH and its receptors play an important role in the pathophysiology of human cancers.
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Affiliation(s)
- Alexandre Havt
- Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, New Orleans, LA 70112-1262, USA
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20
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Jaeger LB, Banks WA, Varga JL, Schally AV. Antagonists of growth hormone-releasing hormone cross the blood-brain barrier: a potential applicability to treatment of brain tumors. Proc Natl Acad Sci U S A 2005; 102:12495-500. [PMID: 16118272 PMCID: PMC1194927 DOI: 10.1073/pnas.0504163102] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Hypothalamic growth hormone (GH)-releasing hormone (GHRH) stimulates the synthesis and release of GH from the pituitary gland. GHRH and its mRNA are also found in human cancers of the breast, ovary, prostate, lung, and other tumors, suggesting that GHRH is also a tumor growth factor. Various studies show that GHRH antagonists have antiproliferative effects in many tumor models; however, glioblastomas were examined only recently. Previous studies have demonstrated that s.c. administration of GHRH antagonist (JV-1-36) inhibited growth of s.c. U-87MG human glioblastomas and increased survival of nude mice with orthotopic implants of glioblastomas. Although treatment with JV-1-36 reduced tumorigenicity, it is not known whether peripherally administered GHRH antagonists can cross the blood-brain barrier. Brain endothelial cells joined by tight junctions form the blood-brain barrier, a "barrier" between the general circulation and the CNS. In this study, we administered a GHRH antagonist (JV-1-42) and showed that, after i.v. injection, iodinated JV-1-42 (131I-JV-1-42) enters the brain intact at a rate of 0.8514 mocrol/g per min with a serum half-life of 12.2 min. A one-site binding hyperbolic model indicated that the maximal percent of i.v. dose taken up per gram of brain was 0.41%. Coinjection of unlabeled JV-1-42 indicated that the transport from blood to brain is not saturable; however, transport from brain to blood is saturable and involves P-glycoprotein. Taken together, these results demonstrate that i.v.-administered 131I-JV-1-42 readily crosses the blood-brain barrier and accumulates in the brain. This finding indicates that GHRH antagonists could provide a potential treatment for malignant glioblastomas.
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Affiliation(s)
- Laura B Jaeger
- Department of Pharmacological and Physiological Sciences, Division of Geriatrics, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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21
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Keller G, Schally AV, Groot K, Toller GL, Havt A, Köster F, Armatis P, Halmos G, Zarandi M, Varga JL, Engel JB. Effective treatment of experimental human non-Hodgkin's lymphomas with antagonists of growth hormone-releasing hormone. Proc Natl Acad Sci U S A 2005; 102:10628-33. [PMID: 16027368 PMCID: PMC1180787 DOI: 10.1073/pnas.0504102102] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Antagonists of growth hormone-releasing hormone (GHRH) were shown to inhibit the growth of various cancers. We investigated the antitumor activity and the mechanism of action of GHRH antagonists in human non-Hodgkin's lymphomas (NHL). Nude mice bearing xenografts of RL and HT human NHL were treated with GHRH antagonists MZ-5-156 and MZ-J-7-138 at a dose of 40 microg twice daily. The concentrations of serum IGF-1 and GHRH, bFGF, and VEGF in tumor tissue were measured by radioimmunoassays. Expression of GHRH and splice variant 1 of the GHRH receptor in both cell lines was examined by RT-PCR. The effects of MZ-5-156, MZ-J-7-138 and GHRH on cell proliferation were evaluated in vitro. Treatment with MZ-5-156 and MZ-J-7-138 significantly (P < 0.05) inhibited the growth of RL and HT tumors by 59.9-73.9%. High-affinity binding sites for GHRH and mRNA for GHRH and splice variant-1 of the GHRH receptors were found on RL and HT tumors. RL and HT cells contained GHRH peptide, and their growth in vitro was significantly inhibited by both antagonists. IGF-I levels in serum of mice were significantly decreased by antagonist MZ-5-156. Therapy with GHRH antagonists also significantly reduced tumoral bFGF, whereas VEGF levels were not suppressed. Our findings suggest that GHRH antagonists inhibit the growth of RL and HT lymphomas by direct effects mediated by tumoral receptors for GHRH. GHRH antagonists could offer a new therapeutic modality for the management of advanced NHL.
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Affiliation(s)
- Gunhild Keller
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, and Section of Experimental Medicine, Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA
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22
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Freddi S, Arnaldi G, Fazioli F, Scarpelli M, Appolloni G, Mancini T, Kola B, Bertagna X, Mantero F, Collu R, Boscaro M. Expression of growth hormone-releasing hormone receptor splicing variants in human primary adrenocortical tumours. Clin Endocrinol (Oxf) 2005; 62:533-8. [PMID: 15853821 DOI: 10.1111/j.1365-2265.2005.02253.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Several splice variants (SVs) of GHRH receptor (GHRH-R) have been identified in various human cancers through which GHRH antagonists may exert their IGF-II-mediated antiproliferative action. Because the overexpression of the IGF-II gene is a frequent feature of adrenal carcinoma, we searched for the presence of GHRH-R SVs in these tumours. METHODS AND RESULTS The expression of GHRH-R SVs was assessed by nested PCR in 45 human adrenocortical tumours. We have amplified 720-, 566- and 335-bp PCR products only in carcinomas. Their sequence revealed three open reading frames, corresponding to SV1, SV2 and SV4 of GHRH-R. SV2 was detected in five of 24 cancers examined, whereas the incidence of SV1 and SV4 was lower. Their simultaneous expression was observed in one carcinoma. No PCR products for SV3 or wild-type GHRH-R were found in carcinomas; mRNA for wild-type GHRH-R or SVs of GHRH-R were not observed either in adenomas or in normal adrenal or in NCI-H295R cells. Interestingly, all carcinomas which expressed SVs were also positive for the presence of GHRH mRNA. CONCLUSION This is the first time that the expression of splice variants of GHRH-R has been demonstrated in human adrenal carcinoma. This study raises the possibility that splice variants might play a role in adrenal carcinogenesis and might offer the possibility for new therapeutic strategies at least in a subgroup of adrenal carcinomas.
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Affiliation(s)
- Simona Freddi
- Division of Endocrinology, Institute of Clinical Medicine and Applied Biotechnology, Ancona, Italy
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23
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Abstract
Growth hormone-releasing hormone (GHRH) is a neuropeptide secreted by the hypothalamus that stimulates the synthesis and release of growth hormone (GH) in the pituitary. Accumulating evidence suggests that in addition to GHRH's neuroendocrine action, GHRH is present in several extrahypothalamic tissues and is involved in a variety of cellular processes. Its function is related to the regulation of cell proliferation and differentiation of various nonpituitary cell types. In certain cases, ectopic production of GHRH has also been implicated in carcinogenesis. The mechanisms by which GHRH affects the peripheral extrapituitary tissues remain poorly understood, but it is likely that classic neuroendocrine action as well as paracrine and autocrine pathways are involved. Some headway has been made in the identification of extrapituitary receptors for GHRH and cDNA as splice variants of these GHRH receptors found in various tumors. The fact that the nonpituitary GHRH receptors are not fully identified, however, remains the major obstacle in studying, at a more mechanistic level, the action of local GHRH. This review summarizes the information available regarding the role of GHRH in the extrapituitary tissues with emphasis on its potential therapeutic and diagnostic applications.
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Affiliation(s)
- Hippokratis Kiaris
- Department of Biological Chemistry, Medical School, University of Athens, 115 27 Athens, Greece
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24
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Toller GL, Horvath JE, Schally AV, Halmos G, Varga JL, Groot K, Chism D, Zarandi M. Development of a polyclonal antiserum for the detection of the isoforms of the receptors for human growth hormone-releasing hormone on tumors. Proc Natl Acad Sci U S A 2004; 101:15160-5. [PMID: 15469915 PMCID: PMC524040 DOI: 10.1073/pnas.0406348101] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antagonists of growth hormone-releasing hormone (GHRH) inhibit the growth of various human cancers by multiple mechanisms, which include direct effects on tumor cells through the splice variants (SV) of the GHRH receptor. Our findings suggest that the tumoral protein encoded by SV 1 (SV1) is a likely functional receptor. The aim of this study was to develop a polyclonal antiserum against a polypeptide analog of segment 1-25 of the putative SV1 receptor protein. Rabbits were immunized with [Ala-23]SV1 (1-25)-Tyr-26-Cys-27-NH2 as a hapten, conjugated to BSA or keyhole limpet hemocyanin. The antisera thus generated were evaluated by RIA for binding to the radiolabeled hapten. The specificity and sensitivity of the antisera were studied on xenografts of RL and HT human non-Hodgkin's lymphomas. The sera raised against keyhole limpet hemocyanin-SV1 hapten, showed binding values of 50-75% at a 1:56,000 dilution. In Western blot analyses, the purified polyclonal antibody recognized a specific signal with a molecular mass of approximately 40 kDa in RL and HT lymphomas. This band corresponds to the estimated molecular mass of the GHRH receptor isoform encoded by SV1. RT-PCR and ligand binding studies also revealed the expression of SV1 and the presence of high-affinity binding sites for GHRH on RL and HT tumors. Because the antiserum developed recognizes the tumoral GHRH receptor protein encoded by SV1, it should be of value in various investigations.
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MESH Headings
- Animals
- Antibodies/isolation & purification
- Cell Line, Tumor
- Female
- Genetic Variation
- Humans
- Lymphoma, Non-Hodgkin/genetics
- Lymphoma, Non-Hodgkin/metabolism
- Mice
- Mice, Nude
- Neoplasms/genetics
- Neoplasms/metabolism
- Protein Isoforms/genetics
- Protein Isoforms/immunology
- Protein Isoforms/metabolism
- Rabbits
- Receptors, Neuropeptide/genetics
- Receptors, Neuropeptide/immunology
- Receptors, Neuropeptide/metabolism
- Receptors, Pituitary Hormone-Regulating Hormone/genetics
- Receptors, Pituitary Hormone-Regulating Hormone/immunology
- Receptors, Pituitary Hormone-Regulating Hormone/metabolism
- Transplantation, Heterologous
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Affiliation(s)
- Gabor L Toller
- Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, New Orleans, LA 70112-1262, USA
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25
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Kiaris H, Koutsilieris M, Kalofoutis A, Schally AV. Growth hormone-releasing hormone and extra-pituitary tumorigenesis: therapeutic and diagnostic applications of growth hormone-releasing hormone antagonists. Expert Opin Investig Drugs 2003; 12:1385-94. [PMID: 12882623 DOI: 10.1517/13543784.12.8.1385] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Growth hormone-releasing hormone (GHRH) regulates growth hormone release from the pituitary. However, in addition to this neuroendocrine action, much evidence implies an additional role for GHRH in carcinogenesis in non-pituitary tissues. This role of GHRH in cancer development appears to be due to the operation of several mechanisms, which involve the regulation of the growth hormone-dependent hepatic insulin-like growth factor I (IGFI) production, tumoural IGF-I and IGF-II secretion and direct action of GHRH on tumour cells by autocrine and/or paracrine pathways. This review summarises the available information regarding the role of GHRH in tumorigenesis with special emphasis on the direct action of GHRH in primary and experimental cancers.
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Affiliation(s)
- Hippokratis Kiaris
- Department of Biological Chemistry, Medical School, University of Athens, 75 Micras Asias, 115 27 Athens, Greece.
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26
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Siejka A, Ławnicka H, Komorowski J, Schally AV, Stepień T, Krupiński R, Stepień H. GH-RH antagonist (MZ-4-71) inhibits VEGF secretion and proliferation of murine endothelial cells. Life Sci 2003; 72:2473-9. [PMID: 12650855 DOI: 10.1016/s0024-3205(03)00164-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Angiogenesis plays a key role in solid tumor formation, invasiveness and metastasis. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen that is necessary in the process of neovascularisation. Antagonists of growth hormone-releasing hormone (GH-RH) have been shown to suppress both in vivo and in vitro growth and metastasis of many human cancer cell lines. The mechanisms that mediate the antitumorigenic actions of these antagonists involve direct and indirect pathways, but are not completely elucidated. We have examined the effect of GH-RH antagonist MZ-4-71 on proliferation activity and VEGF release from cultured murine endothelial cells HECa10 in vitro. MZ-4-71 at 10(-8) to 10(-6) M concentrations inhibited the proliferative activity of cultured cells and suppressed the release of VEGF into supernatants of 72 h endothelial cell cultures. To our knowledge this is the first study reporting antiangiogenic properties of GH-RH antagonists.
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Affiliation(s)
- A Siejka
- Institute of Endocrinology, Medical University of Łódź, 91-425, Sterlinga 3, Łódź, Poland
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27
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Abstract
Ghrelin is a recently identified 28 amino acid peptide capable of stimulating pituitary growth hormone release in humans. The actions of ghrelin are mediated via the naturally occurring ghrelin receptor, also known as the growth hormone secretagogue receptor (GHS-R). Ghrelin and its receptors are now being recognized as components of the growth hormone axis and are therefore potentially involved in tissue growth and development. As is the case for other members of this axis, evidence is rapidly emerging to indicate that ghrelin/GHS-R may play an important autocrine/paracrine role in some cancers. This review highlights the evidence for the expression, regulation and potential functional role of ghrelin and its receptor in hormone-dependent cancers, such as prostate and breast cancer.
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Affiliation(s)
- Penny L Jeffery
- Queensland University of Technology, 2 George St, Brisbane, Qld 4000, Australia.
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28
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Busto R, Schally AV, Braczkowski R, Plonowski A, Krupa M, Groot K, Armatis P, Varga JL. Expression of mRNA for growth hormone-releasing hormone and splice variants of GHRH receptors in human malignant bone tumors. Regul Pept 2002; 108:47-53. [PMID: 12220726 DOI: 10.1016/s0167-0115(02)00109-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Splice variants (SV) of receptors for growth hormone-releasing hormone (GHRH) have been found in several human cancer cell lines. GHRH antagonists inhibit growth of various human cancers, including osteosarcomas and Ewing's sarcoma, xenografted into nude mice or cultured in vitro and their antiproliferative action could be mediated, in part, through these SV of GHRH receptors. In this study, we found mRNA for the SV(1) isoform of GHRH receptors in human osteosarcoma line MNNG/HOS and SK-ES-1 Ewing's sarcoma line. We also detected mRNA for GHRH, which is apparently translated into the GHRH peptide and secreted by the cells, as shown by the presence of GHRH-like immunoreactivity in the conditioned media of cell cultures. In proliferation studies in vitro, the growth of SK-ES-1 and MNNG/HOS cells was dose-dependently inhibited by GHRH antagonist JV-1-38 and an antiserum against human GHRH. Our study indicates the presence of an autocrine stimulatory loop based on GHRH and SV(1) of GHRH receptors in human sarcomas. The direct antiproliferative effects of GHRH antagonists on malignant bone tumors appear to be exerted through the SV(1) of GHRH receptors on tumoral cells.
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Affiliation(s)
- R Busto
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, New Orleans, LA 70112, USA
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29
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Braczkowski R, Schally AV, Plonowski A, Varga JL, Groot K, Krupa M, Armatis P. Inhibition of proliferation in human MNNG/HOS osteosarcoma and SK-ES-1 Ewing sarcoma cell lines in vitro and in vivo by antagonists of growth hormone-releasing hormone: effects on insulin-like growth factor II. Cancer 2002; 95:1735-45. [PMID: 12365022 DOI: 10.1002/cncr.10865] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Antagonists of growth hormone-releasing hormone (GH-RH) can inhibit the proliferation of various tumors either indirectly through the suppression of the pituitary growth hormone/hepatic insulin-like growth factor I (IGF-I) axis and the lowering of serum IGF-I concentration or directly by reducing the levels of IGF-I and IGF-II and their mRNA expression in tumors and blocking the effect of autocrine GH-RH. In this study, the authors investigated the effects of the GH-RH antagonist JV-1-38 on MNNG/HOS human osteosarcoma and SK-ES-1 human Ewing sarcoma cell lines. METHODS Male nude mice bearing subcutaneous xenografts of MNNG/HOS or SK-ES-1 tumors were treated subcutaneously with JV-1-38 at a dose of 20 microg twice daily for 4 weeks. The concentrations of IGF-I and IGF-II in serum and in tumor tissue were measured by radioimmunoassay. Tumor and liver levels of mRNA for IGF-I and IGF-II were determined by reverse transcriptase-polymerase chain reaction analysis. The effects of JV-1-38, IGF-I, and IGF-II on cell proliferation in vitro were evaluated. RESULTS GH-RH antagonist significantly (P < 0.05) inhibited the tumor volume and tumor weight of MNNG/HOS and SK-ES-1 tumors by > 50% after 4 weeks and increased tumor doubling time. JV-1-38 lowered the serum IGF-I level, decreased the expression of mRNA for IGF-I in the liver, and significantly (P < 0.05-0.01) reduced the concentration of IGF-II and mRNA levels for IGF-II in both sarcomas. The concentration of IGF-I was lowered only in SK-ES-1 tumors. In vitro, the proliferation of SK-ES-1 and MNNG/HOS cells was inhibited by JV-1-38 and by antisera to IGF-I and IGF-II. CONCLUSIONS The inhibition of MNNG/HOS osteosarcoma and SK-ES-1 Ewing sarcoma by GH-RH antagonists was linked to a suppression of IGF-II production in tumors. However, in SK-ES-1 tumors, the effects on IGF-I also may be involved.
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Affiliation(s)
- Ryszard Braczkowski
- Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, New Orleans, Louisiana 70112-1262, USA
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30
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Busto R, Schally AV, Varga JL, Garcia-Fernandez MO, Groot K, Armatis P, Szepeshazi K. The expression of growth hormone-releasing hormone (GHRH) and splice variants of its receptor in human gastroenteropancreatic carcinomas. Proc Natl Acad Sci U S A 2002; 99:11866-71. [PMID: 12186980 PMCID: PMC129360 DOI: 10.1073/pnas.182433099] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2002] [Indexed: 12/28/2022] Open
Abstract
Splice variants (SVs) of receptors for growth hormone-releasing hormone (GHRH) have been found in primary human prostate cancers and diverse human cancer cell lines. GHRH antagonists inhibit growth of various experimental human cancers, including pancreatic and colorectal, xenografted into nude mice or cultured in vitro, and their antiproliferative action could be mediated in part through SVs of GHRH receptors. In this study we examined the expression of mRNA for GHRH and for SVs of its receptors in tumors of human pancreatic, colorectal, and gastric cancer cell lines grown in nude mice. mRNA for both GHRH and SV(1) isoform of GHRH receptors was expressed in tumors of pancreatic (SW1990, PANC-1, MIA PaCa-2, Capan-1, Capan-2, and CFPAC1), colonic (COLO 320DM and HT-29), and gastric (NCI-N87, HS746T, and AGS) cancer cell lines; mRNA for SV(2) was also present in Capan-1, Capan-2, CFPAC1, HT-29, and NCI-N87 tumors. In proliferation studies in vitro, the growth of pancreatic, colonic, and gastric cancer cells was stimulated by GHRH(1-29)NH(2) and inhibited by GHRH antagonist JV-1-38. The stimulation of some gastroenteropancreatic cancer cells by GHRH was followed by an increase in cAMP production, and GHRH antagonist JV-1-38 competitively inhibited this effect. Our study indicates the presence of an autocrine/paracrine stimulatory loop based on GHRH and SV(1) of GHRH receptors in human pancreatic, colorectal, and gastric cancers. The finding of SV(1) receptor in human cancers provides an approach to an antitumor therapy based on the blockade of this receptor by specific GHRH antagonists.
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Affiliation(s)
- Rebeca Busto
- Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, and Section of Experimental Medicine, Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA
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Kiaris H, Schally AV, Busto R, Halmos G, Artavanis-Tsakonas S, Varga JL. Expression of a splice variant of the receptor for GHRH in 3T3 fibroblasts activates cell proliferation responses to GHRH analogs. Proc Natl Acad Sci U S A 2002; 99:196-200. [PMID: 11773624 PMCID: PMC117538 DOI: 10.1073/pnas.012590999] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2001] [Indexed: 01/02/2023] Open
Abstract
The stimulatory effects of growth hormone-releasing hormone (GHRH) and the antiproliferative action of GHRH antagonists have been demonstrated in various cancers, but the receptors that mediate these responses are not clearly identified. Recently, we reported that human cancer cell lines express splice variants (SVs) of the receptors for GHRH. SV1 exhibits the greatest similarity to the pituitary GHRH receptor and is most likely to be functional. To ascertain whether SV1 mediates mitogenic effects on nonpituitary tissues, we expressed SV1 in 3T3 mouse fibroblasts and studied the properties of the transfected cells. Radioligand binding assays with (125)I-labeled GHRH antagonist JV-1-42 detected high affinity (K(d) = 0.58 +/- 0.17 nM) binding sites for GHRH with a maximal binding capacity (B(max)) of 103 +/- 17.4 fmol/mg of membrane protein in 3T3 cells transfected with pcDNA3-SV1, whereas the control cells transfected with the empty vector did not show any GHRH binding. Cell proliferation studies showed that cells expressing SV1 are much more sensitive to GHRH analogs than the pcDNA3 controls. Thus, the expression of SV1 augments the stimulatory responses to GHRH(1-29)NH(2) or GHRH agonist JI-38 and inhibitory responses to GHRH antagonist JV-1-38 as compared with pcDNA3 controls. The stimulation of SV1-expressing cells by GHRH or JI-38 is followed by an increase in cAMP production, but no GH release occurs. Vasoactive intestinal peptide had no effect, and its antagonist JV-1-53 did not inhibit the proliferation of SV1-expressing cells stimulated by GHRH. Our results suggest that SV1 could mediate responses of nonpituitary cells and various tumors to GHRH and GHRH antagonists. The presence of SV1 in several human cancer cell lines provides a rationale for antitumor therapy based on the blockade of this receptor by specific GHRH antagonists.
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Affiliation(s)
- Hippokratis Kiaris
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
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Abstract
The use of peptide analogs for the therapy of various cancers is reviewed. Inhibition of the pituitary-gonadal axis forms the basis for oncological applications of luteinizing hormone-releasing hormone (LH-RH) agonists and antagonists, but direct effects on tumors may also play a role. Analogs of somatostatin are likewise used for treatment of various tumors. Radiolabeled somatostatin analogs have been successfully applied for the localization of tumors expressing somatostatin receptors. Studies on the role of tumoral LH-RH, growth hormone-releasing hormone (GH-RH), and bombesin/GRP and their receptors in the proliferation of various tumors are summarized, but the complete elucidation of all the mechanisms involved will require much additional work. Human tumors producing hypothalamic hormones are also discussed. Treatment of many cancers remains a major challenge, but new therapeutic modalities are being developed based on antagonists of GH-RH and bombesin, which inhibit growth factors or their receptors. Other approaches consist of the use of cytotoxic analogs of LH-RH, bombesin, and somatostatin, which can be targeted to receptors for these peptides in various cancers and their metastases. These new classes of peptide analogs should lead to a more effective treatment for various cancers.
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Affiliation(s)
- A V Schally
- Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, 1601 Perdido Str., New Orleans, LA 70112, USA
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Chatzistamou I, Schally AV, Varga JL, Groot K, Busto R, Armatis P, Halmos G. Inhibition of growth and metastases of MDA-MB-435 human estrogen-independent breast cancers by an antagonist of growth hormone-releasing hormone. Anticancer Drugs 2001; 12:761-8. [PMID: 11593058 DOI: 10.1097/00001813-200110000-00008] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Antagonists of growth hormone-releasing hormone (GH-RH) inhibit the growth of various cancers by mechanism(s) that include the suppression of the insulin-like growth factors (IGF)-I and/or -II. In this study, nude mice bearing orthotopic implants of MDA-MB-435 human estrogen-independent breast carcinoma received 39 days of therapy with GH-RH antagonist JV-1-36 (20 microg/day). The treatment significantly inhibited tumor growth by 71.1% (p<0.01) and nullified the metastatic potential of MDA-MB-435 cells. Four of eight control mice (50%) developed metastases in the lymph nodes and one (12.5%) in the lung, but none of the animals receiving JV-1-36 showed metastatic spread. GH-RH antagonist JV-1-36 inhibited the growth of MDA-MB-435 cells in vitro, while IGF-I stimulated it. However, mRNA for IGF-I or -II was not detected in MDA-MB-435 cells, indicating that the suppression of autocrine IGFs may not be involved in the antiproliferative mechanism. Using ligand competition assays with (125)I-labeled GH-RH antagonist JV-1-42, specific high-affinity binding sites for GH-RH were found on tumor membranes. Reverse transcription-polymerase chain reaction revealed the expression of mRNA for GH-RH receptor splice variant-1 in MDA-MB-435 tumors. Our results suggest that the antitumorigenic action of GH-RH antagonists on MDA-MB-435 breast cancer could be direct and mediated by tumoral GH-RH receptors.
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Affiliation(s)
- I Chatzistamou
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, 1601 Perdido Street, New Orleans, LA 70112-1262, USA
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Ito T, Igarashi H, Pradhan TK, Hou W, Mantey SA, Taylor JE, Murphy WA, Coy DH, Jensen RT. GI side-effects of a possible therapeutic GRF analogue in monkeys are likely due to VIP receptor agonist activity. Peptides 2001; 22:1139-51. [PMID: 11445245 DOI: 10.1016/s0196-9781(01)00436-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Growth hormone (GH) is used or is being evaluated for efficacy in treatment of short stature, aspects of aging, cardiac disorders, Crohn's disease, and short bowel syndrome. Therefore, we synthesized several stable growth hormone-releasing factor (GRF) analogues that could be therapeutically useful. One potent analog, [D-Ala(2),Aib(8, 18,)Ala(9, 15, 16, 22, 24-26,)Gab(27)]hGRF(1-27)NH(2) (GRF-6), with prolonged infusion caused severe diarrhea in monkeys; however, it had no side-effects in rats. Because GRF has similarity to VIP/PACAP and VIPomas cause diarrhea, this study investigated the ability of this and other GRF analogues to interact with the VIP/PACAP receptors. Rat VPAC(1)-R (rVPAC(1)-R), human VPAC(1)-R (hVPAC(1)-R), rVPAC(2)-R and hVPAC(2)-R stably transfected CHO and PANC 1 cells were made and T47D breast cancer cells containing native human VPAC(1)-R and AR4-2J cells containing PAC(1)-R were used. hGRF(1-29)NH(2) had low affinity for both rVPAC(1)-R and rVPAC(2)-R while VIP had a high affinity for both receptors. GRF-6 had a low affinity for both rVPAC(1)-R and rVPAC(2)-R and very low affinity for the rPAC(1)-R. VIP had a high affinity, whereas hGRF(1-29)NH(2) had a low affinity for both hVPAC(1)-R and hVPAC(2)-R. In contrast GRF-6, while having a low affinity for hVPAC(2)-R, had relatively higher affinity for the hVPAC(1)-R. In guinea pig pancreatic acini, all GRF analogues were full agonists at the VPAC(1)-R causing enzyme secretion. These results demonstrate that in contrast to native hGRF(1-29)NH(2,) GRF-6 has a relatively high affinity for the human VPAC(1)-R but not for the human VPAC(2)-R, rat VPAC(1)-R, rat VPAC(2)-R or rat PAC(1)-R. These results suggest that the substituted GRF analog, GRF-6, likely causes the diarrheal side-effects in monkeys by interacting with the VPAC(1)-R. Furthermore, they demonstrate significant species differences can exist for possible therapeutic peptide agonists of the VIP/PACAP/GRF receptor family and that it is essential that receptor affinity assessments be performed in human cells or from a closely related species.
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Affiliation(s)
- T Ito
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
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Rekasi Z, Varga JL, Schally AV, Plonowski A, Halmos G, Csernus B, Armatis P, Groot K. Antiproliferative actions of growth hormone-releasing hormone antagonists on MiaPaCa-2 human pancreatic cancer cells involve cAMP independent pathways. Peptides 2001; 22:879-86. [PMID: 11390017 DOI: 10.1016/s0196-9781(01)00413-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We evaluated the effects of GHRH antagonists on the proliferation of MiaPaCa-2 human pancreatic cancer cells and cAMP signaling in vitro. GHRH antagonists inhibited the proliferation of MiaPaCa-2 cells in vitro in a dose-dependent way and caused a significant elevation in cAMP production. In a superfusion system, short-term exposure of the cells to GHRH antagonists evoked an acute, dose-dependent release of cAMP into the medium. Native GHRH, which stimulates cAMP efflux from pituitary at nanomolar doses, did not influence cAMP release from cultured or superfused MiaPaCa-2 cells even at 10-30 microM. VIP, PACAP, secretin and glucagon also did not influence cell proliferation or cAMP production. Adenylate cyclase activator forskolin (FSK) caused a greater cAMP response, but a smaller antiproliferative effect than GHRH antagonists. Combined treatment with FSK and GHRH antagonist JV-1-38 potentiated the cAMP-inducing effect of FSK, but did not produce a greater inhibition of cell proliferation than JV-1-38 alone. A selective accumulation of radiolabeled GHRH antagonist [(125)I]JV-1-42 in vivo in MiaPaCa-2 carcinoma xenografted into nude mice was also observed. In conclusion, second messengers other than cAMP participate in the signal transduction pathways of GHRH analogs mediated by tumoral GHRH receptors.
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Affiliation(s)
- Z Rekasi
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, New Orleans, LA 70112, USA
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Kiaris H, Schally AV, Armatis P. Direct action of growth hormone-releasing hormone agonist JI-38 on normal human fibroblasts: evidence from studies on cell proliferation and c-myc proto-oncogene expression. Regul Pept 2001; 96:119-24. [PMID: 11111017 DOI: 10.1016/s0167-0115(00)00166-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Growth hormone-releasing hormone (GHRH) is secreted by the hypothalamus and stimulates the release of growth hormone from the pituitary. Recent studies also indicate that in addition to its neuroendocrine function, GHRH may play a direct role in the proliferation of cancer cells, acting as growth factor for various human tumors. In the present study we investigated the effects of JI-38, an agonistic analog of GHRH, on the rate of proliferation of normal human diploid dermal fibroblasts (NHF) cultured in vitro. The effects of JI-38 on the levels of mRNA for c-myc proto-oncogene were also tested. Exposure to 10(-7) M JI-38 stimulated the rate of proliferation of early passage NHF by about 100%. Exposure of NHF cells to 10(-8)-5x10(-6) M JI-38 for 24 h resulted in about 0.5-3.5 fold increase in the levels of mRNA for c-myc proto-oncogene. The ability of JI-38 to stimulate the proliferation of NHF cells was abolished in cells cultured at late passage. Continuous exposure to 10(-7) M JI-38, over 6-7 passages (15-20 population doublings), progressively reduced the rate of proliferation of NHF compared with cells exposed to medium alone, indicating that GHRH agonist acted as a growth inhibitor. Our results suggest that at certain developmental stages, GHRH may act on various tissues, stimulating cell proliferation.
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Affiliation(s)
- H Kiaris
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center and Section of Experimental Medicine, Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112-1262, USA
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Halmos G, Schally AV, Varga JL, Plonowski A, Rekasi Z, Czompoly T. Human renal cell carcinoma expresses distinct binding sites for growth hormone-releasing hormone. Proc Natl Acad Sci U S A 2000; 97:10555-60. [PMID: 10962030 PMCID: PMC27063 DOI: 10.1073/pnas.180313097] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2000] [Indexed: 12/28/2022] Open
Abstract
Antagonists of growth hormone-releasing hormone (GHRH) inhibit the proliferation of various human cancers in vitro and in vivo by mechanisms that include apparent direct effects through specific binding sites expressed on tumors and that differ from pituitary human GHRH (hGHRH) receptors. In this study, GHRH antagonist JV-1-38 (20 microgram/day per animal s.c.) inhibited the growth of orthotopic CAKI-1 human renal cell carcinoma (RCC) by 83% and inhibited the development of metastases to lung and lymph nodes. Using ligand competition assays with (125)I-labeled GHRH antagonist JV-1-42, we demonstrated the presence of specific high-affinity (K(d) = 0.25 +/- 0.03 nM) binding sites for GHRH with a maximal binding capacity (B(max)) of 70.2 +/- 4.1 fmol/mg of membrane protein in CAKI-1 tumors. These receptors bind GHRH antagonists preferentially and display a lower affinity for hGHRH. The binding of (125)I-JV-1-42 is not inhibited by vasoactive intestinal peptide (VIP)-related peptides sharing structural homology with hGHRH. The receptors for GHRH antagonists on CAKI-1 tumors are distinct from binding sites detected with (125)I-VIP (K(d) = 0.89 +/- 0.14 nM; B(max) = 183.5 +/- 2.6 fmol/mg of protein) and also have different characteristics from GHRH receptors on rat pituitary as documented by the insignificant binding of [His(1),(125)I-Tyr(10), Nle(27)]hGHRH(1-32)NH(2). Reverse transcription-PCR revealed the expression of splice variants of hGHRH receptor in CAKI-1 RCC. Biodistribution studies demonstrate an in vivo uptake of (125)I-JV-1-42 by the RCC tumor tissue. The presence of specific receptor proteins that bind GHRH antagonists in CAKI-1 RCC supports the view that distinct binding sites that mediate the inhibitory effect of GHRH antagonists are present on various human cancers.
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Affiliation(s)
- G Halmos
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center and Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA
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Rekasi Z, Czompoly T, Schally AV, Halmos G. Isolation and sequencing of cDNAs for splice variants of growth hormone-releasing hormone receptors from human cancers. Proc Natl Acad Sci U S A 2000; 97:10561-6. [PMID: 10962031 PMCID: PMC27064 DOI: 10.1073/pnas.180313297] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2000] [Indexed: 01/15/2023] Open
Abstract
The proliferation of various tumors is inhibited by the antagonists of growth hormone-releasing hormone (GHRH) in vitro and in vivo, but the receptors mediating the effects of GHRH antagonists have not been identified so far. Using an approach based on PCR, we detected two major splice variants (SVs) of mRNA for human GHRH receptor (GHRH-R) in human cancer cell lines, including LNCaP prostatic, MiaPaCa-2 pancreatic, MDA-MB-468 breast, OV-1063 ovarian, and H-69 small-cell lung carcinomas. In addition, high-affinity, low-capacity binding sites for GHRH antagonists were found on the membranes of cancer cell lines such as MiaPaCa-2 that are negative for the vasoactive intestinal peptide/pituitary adenylate cyclase-activating polypeptide receptor (VPAC-R) or lines such as LNCaP that are positive for VPAC-R. Sequence analysis of cDNAs revealed that the first three exons in SV(1) and SV(2) are replaced by a fragment of retained intron 3 having a new putative in-frame start codon. The rest of the coding region of SV(1) is identical to that of human pituitary GHRH-R, whereas in SV(2) exon 7 is spliced out, resulting in a 1-nt upstream frameshift, which leads to a premature stop codon in exon 8. The intronic sequence may encode a distinct 25-aa fragment of the N-terminal extracellular domain, which could serve as a proposed signal peptide. The continuation of the deduced protein sequence coded by exons 4-13 in SV(1) is identical to that of pituitary GHRH-R. SV(2) may encode a GHRH-R isoform truncated after the second transmembrane domain. Thus SVs of GHRH-Rs have now been identified in human extrapituitary cells. The findings support the view that distinct receptors are expressed on human cancer cells, which may mediate the antiproliferative effect of GHRH antagonists.
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Affiliation(s)
- Z Rekasi
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA
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Kahán Z, Varga JL, Schally AV, Rékási Z, Armatis P, Chatzistamou L, Czömpöly T, Halmos G. Antagonists of growth hormone-releasing hormone arrest the growth of MDA-MB-468 estrogen-independent human breast cancers in nude mice. Breast Cancer Res Treat 2000; 60:71-9. [PMID: 10845811 DOI: 10.1023/a:1006363230990] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Since antagonists of growth hormone-releasing hormone (GH-RH) inhibit proliferation of various tumors, in this study we investigated the effects of GH-RH antagonists MZ-5-156 or JV-1-36 on growth of estrogen-independent MDA-MB-468 human breast cancers xenografted into nude mice. Both GH-RH antagonists administered at a dose of 20 microg/day induced regression of some and growth-arrest of other tumors, while control tumors continued to grow. After 5 weeks of therapy with MZ-5-156 or JV-1-36, final volume and weight of MDA-MB-468 tumors were significantly decreased (all p values < 0.001) and serum IGF-I levels as well as tumor IGF-I mRNA expression were reduced as compared with controls. High affinity binding sites for IGF-I were detected by the ligand binding method. Gene expression of human IGF-I receptors, as measured by the RT-PCR, was not significantly different in control and treated MDA-MB-468 tumors. In cell culture, IGF-I did not stimulate, GH-RH slightly stimulated, while MZ-5-156 and JV-1-36 inhibited proliferation of MDA-MB-468 cells known to possess defective insulin and IGF-I receptor signaling. The expression of mRNA for human GH-RH was found in five of 8 tumors treated with GH-RH antagonists, and in one of the five control tumors. These results suggest that GH-RH antagonists inhibit MDA-MB-468 breast cancers possibly through mechanisms involving interference with locally produced GH-RH.
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MESH Headings
- Animals
- Breast Neoplasms/drug therapy
- Breast Neoplasms/genetics
- Breast Neoplasms/pathology
- DNA Primers
- Disease Models, Animal
- Female
- Gene Expression Regulation, Neoplastic
- Growth Hormone-Releasing Hormone/analogs & derivatives
- Growth Hormone-Releasing Hormone/antagonists & inhibitors
- Growth Hormone-Releasing Hormone/genetics
- Growth Hormone-Releasing Hormone/pharmacology
- Growth Hormone-Releasing Hormone/therapeutic use
- Humans
- Insulin-Like Growth Factor I/genetics
- Insulin-Like Growth Factor I/metabolism
- Insulin-Like Growth Factor II/genetics
- Insulin-Like Growth Factor II/metabolism
- Mice
- Mice, Nude
- RNA, Messenger/genetics
- Radioimmunoassay
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/metabolism
- Receptors, Neuropeptide/genetics
- Receptors, Neuropeptide/metabolism
- Receptors, Pituitary Hormone-Regulating Hormone/genetics
- Receptors, Pituitary Hormone-Regulating Hormone/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sermorelin/analogs & derivatives
- Sermorelin/pharmacology
- Sermorelin/therapeutic use
- Transplantation, Heterologous
- Tumor Cells, Cultured/drug effects
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Affiliation(s)
- Z Kahán
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center New Orleans, Louisiana 70112-1262, USA
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