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Ma Y, Gao F. Advances of radiolabeled GRPR ligands for PET/CT imaging of cancers. Cancer Imaging 2024; 24:19. [PMID: 38279185 PMCID: PMC10811881 DOI: 10.1186/s40644-024-00658-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 01/09/2024] [Indexed: 01/28/2024] Open
Abstract
GRPR is a type of seven-transmembrane G-protein coupled receptor that belongs to the bombesin protein receptor family. It is highly expressed in various cancers, including prostate cancer, breast cancer, lung cancer, gastrointestinal cancer, and so on. As a result, molecular imaging studies have been conducted using radiolabeled GRPR ligands for tumor diagnosis, as well as monitoring of recurrence and metastasis. In this paper, we provided a comprehensive overview of relevant literature from the past two decades, with a specific focus on the advancements made in radiolabeled GRPR ligands for imaging prostate cancer and breast cancer.
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Affiliation(s)
- Yuze Ma
- Research Center for Experimental Nuclear Medicine, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Feng Gao
- Research Center for Experimental Nuclear Medicine, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China.
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Zhang J, Zhou H, Li P, Shi H, Sui X, Wang Y, Shi J, Wang L. Hypothalamic response with PKA/CREB signaling is associated with direct cerebroventricular administration of bombesin-induced scratching. Brain Res 2022; 1789:147950. [PMID: 35618015 DOI: 10.1016/j.brainres.2022.147950] [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: 12/19/2021] [Revised: 04/29/2022] [Accepted: 05/19/2022] [Indexed: 11/28/2022]
Abstract
Bombesin (BN) is an itch-specific mediator that causes intense itch-scratching activity in mammals. Although most examinations of BN-induced itch processing have focused on the spinal cord, the involvement of central nervous system mechanisms remains unclear. Here, we investigated how relationships among hypothalamic regions regulate BN-mediated itch-scratch processes. We found that intracerebroventricular (i.c.v.) administration of BN (0.04-4 μg) elicited intense itch scratching in mice, whereas BN (0.4-400 μg) administered via intravenous tail injection failed to evoke a scratching response. Additionally, nalfurafine had no significant effects on BN-induced scratching behavior, indicating that central modulation of BN is distinct from histamine-mediated histaminergic itch and chloroquine-mediated non-histaminergic itch signaling pathways. We labeled BN with a fluorescent tag, 7-nitrobenz-2-oxa-1 (NBD), and traced its fluorescence in the hypothalamus for 30 min following i.c.v. NBD-BN administration. Accordingly, we confirmed that i.c.v. administration of BN enhanced c-Fos expression in the dorsal medial nucleus of the hypothalamus, where neuromedin B receptors and gastrin-releasing peptide receptors are highly expressed. Interestingly, in situ injection of BN into the hypothalamus immediately and robustly induced itch-scratching behavior. Moreover, gene transcripts and western blot assay revealed that BN receptor-dependent PKA/CREB signaling was upregulated in the hypothalamus after i.c.v. administration of BN. Consistently, pretreatment with a PKA inhibitor, Rp-cAMP, significantly reduced BN-induced scratching behavior. Our results indicate that the dorsal medial nucleus of the hypothalamus may be a key nucleus in mediating BN-mediated itch and hypothalamic PKA/CREB signaling is involved in regulating BN-mediated itch.
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Affiliation(s)
- Jingxin Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China; The Key Laboratory of Basic Pharmacology of the Educational Minister, Zunyi Medical University, Zunyi, Guizhou 563000, China.
| | - Hu Zhou
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Pengfei Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Huaxiang Shi
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Xin Sui
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Yongan Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Jingshan Shi
- The Key Laboratory of Basic Pharmacology of the Educational Minister, Zunyi Medical University, Zunyi, Guizhou 563000, China.
| | - Liyun Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
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Abstract
PURPOSE OF REVIEW Description of the recent findings of the biological roles of bombesin-like peptides and their receptors in lungs. RECENT FINDINGS Gastrin-releasing peptide (GRP) was involved in the airway inflammation in murine models of airway hyperreactivity. The circulating proGRP could serve as a valuable tumor marker for small-cell lung cancers, and the plasma level of proGRP is more stable compared with that of serum proGRP. Recent studies also shed light on the intracellular signaling pathways of bombesin receptor subtype-3 (BRS-3) activation in cultured human lung cancer cells. SUMMARY The relevant biology of BLPs and their receptors in lung cancers and other lung diseases still remains largely unknown. With the development of several highly specific BRS-3 agonists, recent studies provided some insights into the biological effects of BRS-3 in lungs.
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Affiliation(s)
- Xiao-Qun Qin
- Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, P.R. China.
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Qin X, Qu X, Coy D, Weber HC. A Selective Human Bombesin Receptor Subtype-3 Peptide Agonist Mediates CREB Phosphorylation and Transactivation. J Mol Neurosci 2011; 46:88-99. [DOI: 10.1007/s12031-011-9675-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 11/07/2011] [Indexed: 01/08/2023]
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Li X, Lv Y, Yuan A, Li Z. Gastrin-releasing peptide links stressor to cancer progression. J Cancer Res Clin Oncol 2010; 136:483-91. [PMID: 20140628 DOI: 10.1007/s00432-010-0766-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 01/13/2010] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Gastrin-releasing peptide (GRP) plays an important role in cancer growth and metastasis; however, the mechanisms of how GRP affects cancer progression are not well understood. Recent studies revealed that chronic stress is a major risk factor for cancer progression, and this effect may be mediated by GRP. In this review, we will discuss the mechanisms and implications of GRP linking stressor to cancer progression. MATERIALS AND METHODS We retrieved the studies of the relationship between GRP, stress and cancers through PubMed using systematic methods to search, select, and evaluate the findings. RESULTS The results suggested that GRP can mediate the effects of stress on cancers at systemic, tissue and cellular levels: Stress elicits the secretion of GRP in the brain and GRP in turn activates the stress response pathways resulting in an elevation of stress hormones and GRP in the plasma and tissues. GRP in synergy with stress hormones stimulates the growth and invasion of cancer cells by suppressing the anti-tumor immune function and directly activating the pro-proliferative and pro-migratory signaling pathways in cancer cells. CONCLUSION GRP is a multi-functional peptide, which acts as a stress mediator as well as a growth factor linking stressor to cancer progression. GRP and its high-affinity receptor are useful targets for the diagnosis and treatment of cancers.
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Affiliation(s)
- Xinqiu Li
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, 277, West Yanta Road, 710061, Xi'an, People's Republic of China
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Abstract
PURPOSE OF REVIEW This review will highlight recent advances in the understanding of molecular mechanisms by which mammalian bombesin receptors are regulated and which intracellular signaling pathways have been characterized to mediate agonist-dependent receptor biological effects. RECENT FINDINGS Mammalian bombesin receptors have been demonstrated to be involved in a larger array of physiological and pathophysiological conditions than previously reported. Pharmacological experiments in vitro and in vivo as well as utilization of animals genetically deficient of the gastrin-releasing peptide receptor demonstrated roles in memory and fear behavior, lung development and injury, small intestinal cell repair, autocrine tumor growth, and mediating signals for pruritus and penile reflexes. Intracellular signaling studies predominantly of the gastrin-releasing peptide receptor owing to its frequent overexpression in some human malignancies showed that PI3 kinase activation is an important mechanism of cell proliferation. Tumor cell treatment including gastrin-releasing peptide receptor antagonists combined with inhibition of epidermal growth factor receptor resulted in an additive effect on blocking cell proliferation. Novel molecular mechanisms of the orphan bombesin receptor subtype-3 and gastrin-releasing peptide receptor gene regulation have been elucidated. SUMMARY Inhibition of gastrin-releasing peptide receptor signaling in human malignancies represents an attractive target for pharmacological treatment. Novel functions of bombesin related peptides have been identified including processes in the central nervous system, lung and intestinal tract.
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Affiliation(s)
- H Christian Weber
- Boston University School of Medicine, Section of Gastroenterology, Boston, MA 02118, USA.
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Chinnappan D, Qu X, Xiao D, Ratnasari A, Weber HC. Human gastrin-releasing peptide receptor gene regulation requires transcription factor binding at two distinct CRE sites. Am J Physiol Gastrointest Liver Physiol 2008; 295:G153-G162. [PMID: 18483184 PMCID: PMC2494719 DOI: 10.1152/ajpgi.00036.2008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ectopic expression of the gastrin-releasing peptide (GRP) receptor (GRP-R) occurs frequently in human malignancies of the gastrointestinal tract. Owing to paracrine and autocrine interaction with its specific high-affinity ligand GRP, tumor cell proliferation, migration, and invasion might ensue. Here we provide the first insights regarding molecular mechanisms of GRP-R regulation in gastrointestinal cancer cells. We identified by EMSA and chromatin immunoprecipitation assays two cAMP response element (CRE) binding sites that recruited transcription factor CRE binding protein (CREB) to the human GRP-R promoter. Transfection studies with a wild-type human GRP-R promoter reporter and corresponding CRE mutants showed that both CRE sites are critical for basal transcriptional activation in gastrointestinal cancer cells. Forced expression of cAMP-dependent effectors CREB and PKA resulted in robust upregulation of human GRP-R transcriptional activity, and this overexpression strictly required intact wild-type CRE sites. Direct cAMP stimulation with forskolin resulted in enhanced human GRP-R promoter activity only in HuTu-80 cells, but not in Caco-2 cells, coinciding with forskolin-induced CREB phosphorylation occurring only in HuTu-80 but not Caco-2 cells. In summary, CREB is a critical regulator of human GRP-R expression in gastrointestinal cancer and might be activated through different upstream intracellular pathways.
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Affiliation(s)
- Dharmaraj Chinnappan
- Boston University School of Medicine, Section of Gastroenterology, Boston, Massachusetts
| | - Xiangping Qu
- Boston University School of Medicine, Section of Gastroenterology, Boston, Massachusetts
| | - Dongmei Xiao
- Boston University School of Medicine, Section of Gastroenterology, Boston, Massachusetts
| | - Anita Ratnasari
- Boston University School of Medicine, Section of Gastroenterology, Boston, Massachusetts
| | - H. Christian Weber
- Boston University School of Medicine, Section of Gastroenterology, Boston, Massachusetts
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Liu X, Carlisle DL, Swick MC, Gaither-Davis A, Grandis JR, Siegfried JM. Gastrin-releasing peptide activates Akt through the epidermal growth factor receptor pathway and abrogates the effect of gefitinib. Exp Cell Res 2007; 313:1361-72. [PMID: 17349623 DOI: 10.1016/j.yexcr.2007.01.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 12/22/2006] [Accepted: 01/26/2007] [Indexed: 11/28/2022]
Abstract
Gastrin-releasing peptide (GRP) is a mitogen for lung epithelial cells and initiates signaling through a G-protein-coupled receptor, gastrin-releasing peptide receptor (GRPR). Because GRPR transactivates the epidermal growth factor receptor (EGFR), we investigated induction by GRP of Akt, an EGFR-activated signaling pathway, and examined effects of GRP on viability of non-small cell lung carcinoma (NSCLC) cells exposed to the EGFR tyrosine kinase inhibitor gefitinib. GRP induced Akt activation primarily through c-Src-mediated transactivation of EGFR. Transfection of dominant-negative c-Src abolished GRP-induced EGFR and Akt activation. GRP induced release of amphiregulin, and pre-incubation with human amphiregulin neutralizing antibody eliminated GRP-induced Akt phosphorylation. Pretreatment with phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 completely blocked GRP-initiated Akt phosphorylation. These results suggest that GRP stimulates Akt activation primarily via c-Src activation, followed by extracellular release of the EGFR ligand amphiregulin, leading to the activation of EGFR and PI3K. Pretreatment of NSCLC cells with GRP resulted in an increase in the IC(50) of gefitinib of up to 9-fold; this protective effect was mimicked by the pretreatment of cells with amphiregulin and reversed by Akt or PI3K inhibition. GRP appears to rescue NSCLC cells exposed to gefitinib through release of amphiregulin and activation of the Akt pathway, suggesting GRPR and/or EGFR autocrine pathways in NSCLC cells may modulate therapeutic response to EGFR inhibitors.
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Affiliation(s)
- Xuwan Liu
- Department of Pharmacology, University of Pittsburgh Cancer Institute, University of Pittsburgh, Lab 2.7, 5117 Centre Ave., Pittsburgh, PA 15213, USA.
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Roesler R, Luft T, Oliveira SHS, Farias CB, Almeida VR, Quevedo J, Dal Pizzol F, Schröder N, Izquierdo I, Schwartsmann G. Molecular mechanisms mediating gastrin-releasing peptide receptor modulation of memory consolidation in the hippocampus. Neuropharmacology 2006; 51:350-7. [PMID: 16735043 DOI: 10.1016/j.neuropharm.2006.03.033] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 03/24/2006] [Accepted: 03/24/2006] [Indexed: 11/16/2022]
Abstract
Although the gastrin-releasing peptide-preferring bombesin receptor (GRPR) has been implicated in memory formation, the underlying molecular events are poorly understood. In the present study, we examined interactions between the GRPR and cellular signaling pathways in influencing memory consolidation in the hippocampus. Male Wistar rats received bilateral infusions of bombesin (BB) into the dorsal hippocampus immediately after inhibitory avoidance (IA) training. Intermediate doses of BB enhanced, whereas a higher dose impaired, 24-h IA memory retention. The BB-induced memory enhancement was prevented by pretraining infusions of a GRPR antagonist or inhibitors of protein kinase C (PKC), mitogen-activated protein kinase (MAPK) kinase and protein kinase A (PKA), but not by a neuromedin B receptor (NMBR) antagonist. We next further investigated the interactions between the GRPR and the PKA pathway. BB-induced enhancement of consolidation was potentiated by coinfusion of activators of the dopamine D1/D5 receptor (D1R)/cAMP/PKA pathway and prevented by a PKA inhibitor. We conclude that memory modulation by hippocampal GRPRs is mediated by the PKC, MAPK, and PKA pathways. Furthermore, pretraining infusion of BB prevented beta-amyloid peptide (25-35)-induced memory impairment, supporting the view that the GRPR is a target for the development of cognitive enhancers for dementia.
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Affiliation(s)
- R Roesler
- Cellular and Molecular Neuropharmacology Research Group, Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Rua Sarmento Leite, Campus Centro/UFRGS, Porto Alegre, RS, Brazil.
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Patel O, Shulkes A, Baldwin GS. Gastrin-releasing peptide and cancer. Biochim Biophys Acta Rev Cancer 2006; 1766:23-41. [PMID: 16490321 DOI: 10.1016/j.bbcan.2006.01.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 01/09/2006] [Accepted: 01/10/2006] [Indexed: 02/07/2023]
Abstract
Over the past 20 years, abundant evidence has been collected to suggest that gastrin-releasing peptide (GRP) and its receptors play an important role in the development of a variety of cancers. In fact, the detection of GRP and the GRP receptor in small cell lung carcinoma (SCLC), and the demonstration that anti-GRP antibodies inhibited proliferation in SCLC cell lines, established GRP as the prototypical autocrine growth factor. All forms of GRP are generated by processing of a 125-amino acid prohormone; recent studies indicate that C-terminal amidation of GRP18-27 is not essential for bioactivity, and that peptides derived from residues 31 to 125 of the prohormone are present in normal tissue and in tumors. GRP receptors can be divided into four classes, all of which belong to the 7 transmembrane domain family and bind GRP and/or GRP analogues with affinities in the nM range. Over-expression of GRP and its receptors has been demonstrated at both the mRNA and protein level in many types of tumors including lung, prostate, breast, stomach, pancreas and colon. GRP has also been shown to act as a potent mitogen for cancer cells of diverse origin both in vitro and in animal models of carcinogenesis. Other actions of GRP relevant to carcinogenesis include effects on morphogenesis, angiogenesis, cell migration and cell adhesion. Future prospects for the use of radiolabelled and cytotoxic GRP analogues and antagonists for cancer diagnosis and therapy appear promising.
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Affiliation(s)
- Oneel Patel
- University of Melbourne, Department of Surgery, Austin Health, Studley Rd., Heidelberg, Victoria 3084, Australia
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Mao JD, Wu P, Xia XH, Hu JQ. Relationship between expression of gastrin, somatostatin mRNA and cell apoptosis and Bcl-2, Bax in large intestinal carcinoma. Shijie Huaren Xiaohua Zazhi 2005; 13:2757-2761. [DOI: 10.11569/wcjd.v13.i23.2757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the correlations the between expression of somatostatin (SS), gastrin (GAS) mRNA and cell apoptosis index (AI) and Bcl-2, Bax in large intestinal cancer.
METHODS: The expression of GAS and SS genes were detected in 62 colorectal cancer patients by nested reverse transcription polymerase chain reaction (RT-PCR), and the apoptosis of the cells was detected by TUNEL method. The protein expression of,Bcl-2, Bax, GAS, and SS were detected using immunohistochemical staining (S-P method).
RESULTS: The expression of GAS and SS mRNA and protein were basically consistent. The AI in SS high and moderate expression patients with large intestinal cancer was remarkably higher than that in SS low expression ones (q = 5.06, 3.95, both P < 0.01), while it was just opposite in GAS positive patients (q = 6.66, 6.33, P < 0.01). The positive rates of Bax and Bcl-2 expression had significant difference between SS (or GAS) high, moderate and low expression patients with large intestinal cancer (Bax: χ2 = 9.24, 6.91, P < 0.05; Bcl-2: χ2 = 7.17, 13.83, P < 0.05). The positive rate of Bax expression in SS high (80%, 8/10) and moderate (76.5%, 13/17) expression patients was notably higher than that in the low expression ones (40.0%, 14/35) (χ2 = 5.24, 6.09, P < 0.05), but the rate of Bcl-2 expression was just opposite (χ2 = 4.71, 4.70, P < 0.05). The positive rate of Bcl-2 expression in GAS high (90.9%,10/11) and moderate expression patients (86.7%,13/15) was markedly higher than that in the low expression ones (44.4%, 16/36) (χ2 = 5.60, 7.69, P < 0.05), but the positive rate of Bax expression in GAS high expression patients (27.3%, 3/8) was obviously lower than that in the low expression ones (69.4%, 25/36) (χ2 = 4.59, P < 0.05). Bax expression was not significantly different between moderate and low GAS positive patients. The value of GAS/SS was positively correlated with Bcl-2 expression (r = 0.34, P < 0.01), but negatively with the AI value and Bax expression (r = -0.546, P < 0.01; r = -0.299, P < 0.05).
CONCLUSION: GAS and SS play important roles in the regulation and control of cell apoptosis in large intestinal carcinoma, and the mechanism may be related to the aberrant expression of Bcl-2 and Bax.
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Patel O, Dumesny C, Giraud AS, Baldwin GS, Shulkes A. Stimulation of proliferation and migration of a colorectal cancer cell line by amidated and glycine-extended gastrin-releasing peptide via the same receptor. Biochem Pharmacol 2005; 68:2129-42. [PMID: 15498503 DOI: 10.1016/j.bcp.2004.08.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Accepted: 08/03/2004] [Indexed: 02/07/2023]
Abstract
Although amidated forms of gastrin-releasing peptide (GRP) have been identified as autocrine growth factors in small cell lung cancer, their role in the development and progression of colorectal carcinoma is less clear. In addition, the biological activity of non-amidated gastrin-releasing peptide has not been investigated in colorectal carcinoma cells. We therefore investigated the effect of bombesin (a homologue of gastrin-releasing peptide) on proliferation, migration and inositol phosphate production in the human colorectal carcinoma cell line DLD-1, and determined the ability of gastrin-releasing peptide receptor antagonists to inhibit these effects. We also compared the biological activities of amidated and non-amidated GRP in the same assays. Treatment with either bombesin, or amidated or non-amidated GRP resulted in significant increase in proliferation, and in migration in a wound-healing assay. Both the mitogenic and migratory effects of amidated and non-amidated forms were inhibited by the GRP receptor antagonist [D-Phe(6), Leu-NHet(13), des-Met(14)]-bombesin(6-13). The presence of GRP receptor mRNA and GRP binding sites in three colorectal carcinoma cell lines was demonstrated by RT-PCR and by binding of radiolabelled bombesin, respectively. Transfection of DLD-1 cells with a dominant negative phosphatidylinositol 3-kinase did not affect bombesin-stimulated cell proliferation, but inhibited bombesin-stimulated cell migration. Bombesin and GRPgly activated phospholipase C, mitogen-activated protein kinase and focal adhesion kinase. We conclude that both amidated and non-amidated forms of gastrin-releasing peptide accelerate proliferation and migration of DLD-1 human colorectal carcinoma cells via the gastrin-releasing peptide receptor, but that phosphatidylinositol 3-kinase is only involved in the cell migration signalling pathway. Our results suggest a potential role for gastrin-releasing peptide receptor antagonists in the management of colorectal carcinoma.
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Affiliation(s)
- Oneel Patel
- Departments of Surgery, Austin Hospital, University of Melbourne, Melbourne, Vic. 3084, Australia
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Abstract
The transactivation domain of the cAMP response element-binding protein (CREB) consists of two major domains. The glutamine-rich Q2 domain, which interacts with the general transcription factor TAFII130/135, is sufficient for the recruitment of a functional RNA polymerase II complex and allows basal transcriptional activity. The kinase-inducible domain, however, mediates signal-induced activation of CREB-mediated transcription. It is generally believed that recruitment of the coactivators CREB-binding protein (CBP) and p300 after signal-induced phosphorylation of this domain at serine-133 strongly enhances CREB-dependent transcription. Transcriptional activity of CREB can also be potentiated by phosphoserine-133-independent mechanisms, and not all stimuli that provoke phosphorylation of serine-133 stimulate CREB-dependent transcription. This review presents an overview of the diversity of stimuli that induce CREB phosphorylation at Ser-133, focuses on phosphoserine-133-dependent and -independent mechanisms that affect CREB-mediated transcription, and discusses different models that may explain the discrepancy between CREB Ser-133 phosphorylation and activation of CREB-mediated transcription.
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Affiliation(s)
- Mona Johannessen
- Department of Biochemistry, Institute of Medical Biology, University of Tromsø, N-9037, Norway
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Chen PW, Kroog GS. Alterations in receptor expression or agonist concentration change the pathways gastrin-releasing peptide receptor uses to regulate extracellular signal-regulated kinase. Mol Pharmacol 2004; 66:1625-34. [PMID: 15361544 DOI: 10.1124/mol.104.001206] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptors activate extracellular signal-regulated kinases (ERKs) via different pathways in different cell types. In this study, we demonstrate that gastrin-releasing peptide receptor (GRPr) regulates ERK through multiple pathways in a single cell type depending upon receptor expression and agonist concentration. We examined stably transfected BALB/c 3T3 fibroblasts expressing GRPr constructs at different levels and treated the cells with several concentrations of bombesin (BN, a GRPr agonist) to activate a variable number of GRPr per cell. GRPr induced two waves of ERK activation and one wave of ERK inhibition. One wave of activation required an intact GRPr carboxyl-terminal domain (CTD). It peaked 6 min after addition of high BN concentration ([BN]) in cells with high GRPr expression. Another wave of activation was CTD-independent. It peaked 2 to 4 min after BN addition in cells when [BN] and/or GRPr expression were lower. The early wave of ERK activation was more sensitive than the later one to pretreatment with Bisindolylmaleimide I (GF 109203X) (a protein kinase C inhibitor) or hypertonic sucrose. Because these two waves of activation differ in time course, dose-response curve, requirement for GRPr CTD, and sensitivity to inhibitors, they result from different signaling pathways. A third pathway in these cells inhibited ERK phosphorylation 2 min after addition of high [BN] in cells with high GRPr expression. Furthermore, a GRPr-expressing human duodenal cancer cell line showed differential sensitivity to GF 109203X throughout BN-induced ERK activation, indicating that GRPr may activate ERK via multiple pathways in cells expressing endogenous GRPr.
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Affiliation(s)
- Pei-Wen Chen
- Department of Molecular Pharmacology, Albert Eistein College of Medicine, Bronx, New York 10461, USA
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Roesler R, Lessa D, Venturella R, Vianna MRM, Luft T, Henriques JAP, Izquierdo I, Schwartsmann G. Bombesin/gastrin-releasing peptide receptors in the basolateral amygdala regulate memory consolidation. Eur J Neurosci 2004; 19:1041-5. [PMID: 15009151 DOI: 10.1111/j.0953-816x.2004.03175.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several receptor and intracellular signalling systems in the basolateral amygdala (BLA) regulate memory formation. In the present study, we show that bombesin/gastrin-releasing peptide (GRP) receptors in the BLA are involved in the consolidation of affectively motivated memory. Adult male rats were trained in a single-trial step-down inhibitory avoidance task and tested for retention 24 h later. Post-training systemic injection of the bombesin/GRP receptor antagonist (D-Tpi6, Leu13 psi[CH2NH]-Leu14) bombesin (6-14) (RC-3095) impaired memory retention. In rats implanted under thionembutal anaesthesia with guide cannulae aimed at the BLA, post-training bilateral infusion of RC-3095 into the BLA dose-dependently impaired retention. Pre-training unilateral muscimol inactivation of the BLA blocked the memory-impairing effect of post-training systemic administration of RC-3095. The results suggest that bombesin/GRP receptors in the BLA are involved in the consolidation of aversive memory, and the BLA mediates the memory-impairing effect of systemic bombesin/GRP receptor blockade.
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Affiliation(s)
- Rafael Roesler
- Preclinical Neuropharmacology Laboratory, Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, 90046-900 Porto Alegre, RS, Brazil.
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Roesler R, Meller CA, Kopschina MI, Souza DO, Henriques JAP, Schwartsmann G. Intrahippocampal infusion of the bombesin/gastrin-releasing peptide antagonist RC-3095 impairs inhibitory avoidance retention. Peptides 2003; 24:1069-74. [PMID: 14499286 DOI: 10.1016/s0196-9781(03)00179-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bombesin (BN)-like peptides regulate cell proliferation and cancer growth as well as neuroendocrine and neural functions. We evaluated the effects of the BN/gastrin-releasing peptide (GRP) antagonist RC-3095 on memory formation. Male Wistar rats were given a bilateral infusion of saline or RC-3095 (0.2, 1.0 or 5.0 microg) into the dorsal hippocampus either immediately or 2 h after training in an inhibitory avoidance (IA) task. Retention test trials were carried out 1.5 h (short-term memory) and 24 h (long-term memory) after training. RC-3095 impaired both short- and long-term retention only when given immediately after training. The results suggest that the hippocampal BN/GRP receptor system modulates IA memory formation.
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Affiliation(s)
- Rafael Roesler
- School of Pharmacy, The Lutheran University of Brazil (ULBRA), 92420-280 Canoas, RS, Brazil.
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Biologic relevance of mammalian bombesin-like peptides and their receptors in human malignancies. ACTA ACUST UNITED AC 2003. [DOI: 10.1097/00060793-200302000-00010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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