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Atanasova KR, Reznikov LR. Neuropeptides in asthma, chronic obstructive pulmonary disease and cystic fibrosis. Respir Res 2018; 19:149. [PMID: 30081920 PMCID: PMC6090699 DOI: 10.1186/s12931-018-0846-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 07/13/2018] [Indexed: 02/07/2023] Open
Abstract
The nervous system mediates key airway protective behaviors, including cough, mucus secretion, and airway smooth muscle contraction. Thus, its involvement and potential involvement in several airway diseases has become increasingly recognized. In the current review, we focus on the contribution of select neuropeptides in three distinct airway diseases: asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. We present data on some well-studied neuropeptides, as well as call attention to a few that have not received much consideration. Because mucus hypersecretion and mucus obstruction are common features of many airway diseases, we place special emphasis on the contribution of neuropeptides to mucus secretion. Finally, we highlight evidence implicating involvement of neuropeptides in mucus phenotypes in asthma, COPD and cystic fibrosis, as well as bring to light knowledge that is still lacking in the field.
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Affiliation(s)
- Kalina R Atanasova
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Drive, PO Box 100144, Gainesville, FL, 32610, USA
| | - Leah R Reznikov
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Drive, PO Box 100144, Gainesville, FL, 32610, USA.
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Egloff AM, Liu X, Davis ALG, Trevelline BK, Vuga M, Siegfried JM, Grandis JR. Elevated gastrin-releasing peptide receptor mRNA expression in buccal mucosa: association with head and neck squamous cell carcinoma. Head Neck 2012; 35:270-9. [PMID: 22431275 DOI: 10.1002/hed.22963] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2011] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Expression of gastrin-releasing peptide receptor (GRPR) is elevated in mucosa adjacent to head and neck squamous cell carcinoma (HNSCC) compared with mucosa from cancer-free controls, suggesting elevated GRPR expression may indicate presence of HNSCC. METHODS We measured GRPR mRNA levels in histologically normal buccal mucosa from 65 surgical patients with HNSCC and 75 cancer-free control subjects using quantitative polymerase chain reaction (PCR). We tested for association between GRPR expression and HNSCC and evaluated differences in patient progression-free survival (PFS). RESULTS Buccal GRPR expression was higher in cases but not controls who were active smokers (p = .04). High GRPR expression was associated with HNSCC (odds ratio [OR] = 3.55; 95% confidence interval [CI] = 1.15-10.93), even after adjustment for age, sex, tobacco use, and sample storage time. PFS did not differ between patients with HNSCC with high versus low GRPR expression (p = .22). CONCLUSION Elevated buccal GRPR expression was significantly associated with HNSCC independent of known risk factors but was not an indicator of disease prognosis.
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Affiliation(s)
- Ann Marie Egloff
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Egloff AM, Gaither Davis A, Shuai Y, Land S, Pilewski JM, Luketich JD, Landreneau R, Miller YE, Grandis JR, Siegfried JM. Gastrin-releasing peptide receptor expression in non-cancerous bronchial epithelia is associated with lung cancer: a case-control study. Respir Res 2012; 13:9. [PMID: 22296774 PMCID: PMC3305653 DOI: 10.1186/1465-9921-13-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 02/01/2012] [Indexed: 11/17/2022] Open
Abstract
Background Normal bronchial tissue expression of GRPR, which encodes the gastrin-releasing peptide receptor, has been previously reported by us to be associated with lung cancer risk in 78 subjects, especially in females. We sought to define the contribution of GRPR expression in bronchial epithelia to lung cancer risk in a larger case-control study where adjustments could be made for tobacco exposure and sex. Methods We evaluated GRPR mRNA levels in histologically normal bronchial epithelial cells from 224 lung cancer patients and 107 surgical cancer-free controls. Associations with lung cancer were tested using logistic regression models. Results Bronchial GRPR expression was significantly associated with lung cancer (OR = 4.76; 95% CI = 2.32-9.77) in a multivariable logistic regression (MLR) model adjusted for age, sex, smoking status and pulmonary function. MLR analysis stratified by smoking status indicated that ORs were higher in never and former smokers (OR = 7.74; 95% CI = 2.96-20.25) compared to active smokers (OR = 1.69; 95% CI = 0.46-6.33). GRPR expression did not differ by subject sex, and lung cancer risk associated with GRPR expression was not modified by sex. Conclusions GRPR expression in non-cancerous bronchial epithelium was significantly associated with the presence of lung cancer in never and former smokers. The association in never and former smokers was found in males and females. Association with lung cancer did not differ by sex in any smoking group.
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Affiliation(s)
- Ann Marie Egloff
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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4
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What can in vitro models of COPD tell us? Pulm Pharmacol Ther 2010; 24:471-7. [PMID: 21182977 DOI: 10.1016/j.pupt.2010.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/09/2010] [Accepted: 12/14/2010] [Indexed: 11/21/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterised by chronic bronchitis, largely irreversible remodelling of the small airways, and emphysematous destruction of the alveoli. COPD is projected to be the third leading cause of death worldwide by 2020. COPD often results from prolonged exposure to irritants such as cigarette smoke or inhaled particulates. Current pharmacotherapies for COPD are unable to reverse the pathological changes of this disease, and this is partially due to a limited understanding of the intricate mechanisms by which chronic exposure lead to the different pathological components of COPD. This review examines how the mechanisms that underlie various components of COPD can be modelled in vitro, specifically using cigarette smoke extract with cells cultured from primary human lung tissue, and how the effectiveness of current and novel pharmacotherapies on successfully attenuating these pathological changes can also be examined in vitro.
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Degan S, Lopez GY, Kevill K, Sunday ME. Gastrin-releasing peptide, immune responses, and lung disease. Ann N Y Acad Sci 2009; 1144:136-47. [PMID: 19076373 DOI: 10.1196/annals.1418.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Gastrin-releasing peptide (GRP) is produced by pulmonary neuroendocrine cells (PNECs), with highest numbers of GRP-positive cells present in fetal lung. Normally GRP-positive PNECs are relatively infrequent after birth, but PNEC hyperplasia is frequently associated with chronic lung diseases. To address the hypothesis that GRP mediates chronic lung injury, we present the cumulative evidence implicating GRP in bronchopulmonary dysplasia (BPD), the chronic lung disease of premature infants who survive acute respiratory distress syndrome. The availability of well-characterized animal models of BPD was a critical tool for demonstrating that GRP plays a direct role in the early pathogenesis of this disease. Potential mechanisms by which GRP contributes to injury are analyzed, with the main focus on innate immunity. Autoreactive T cells may contribute to lung injury late in the course of disease. A working model is proposed with GRP triggering multiple cell types in both the innate and adaptive immune systems, promoting cascades culminating in chronic lung disease. These observations represent a paradigm shift in the understanding of the early pathogenesis of BPD, and suggest that GRP blockade could be a novel treatment to prevent this lung disease in premature infants.
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Affiliation(s)
- Simone Degan
- Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA
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Yang JC, Ok JH, Busby JE, Borowsky AD, Kung HJ, Evans CP. Aberrant activation of androgen receptor in a new neuropeptide-autocrine model of androgen-insensitive prostate cancer. Cancer Res 2009; 69:151-60. [PMID: 19117998 DOI: 10.1158/0008-5472.can-08-0442] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Treatment of advanced prostate cancer with androgen deprivation therapy inevitably renders the tumors castration-resistant and incurable. Under these conditions, neuroendocrine differentiation of prostate cancer (CaP) cells is often detected and neuropeptides released by these cells may facilitate the development of androgen independence. Exemplified by gastrin-releasing peptide (GRP), these neuropeptides transmit their signals through G protein-coupled receptors, which are often overexpressed in prostate cancer, and aberrantly activate androgen receptor (AR) in the absence of androgen. We developed an autocrine neuropeptide model by overexpressing GRP in LNCaP cells and the resultant cell line, LNCaP-GRP, exhibited androgen-independent growth with enhanced motility in vitro. When orthotopically implanted in castrated nude mice, LNCaP-GRP produced aggressive tumors, which express GRP, prostate-specific antigen, and nuclear-localized AR. Chromatin immunoprecipitation studies of LNCaP-GRP clones suggest that GRP activates and recruits AR to the cognate promoter in the absence of androgen. A Src family kinase (SFK) inhibitor, AZD0530, inhibits androgen-independent growth and migration of the GRP-expressing cell lines, and blocks the nuclear translocation of AR, indicating the involvement of SFK in the aberrant activation of AR and demonstrating the potential use of SFK inhibitor in the treatment of castration-resistant CaP. In vivo studies have shown that AZD0530 profoundly inhibits tumor metastasis in severe combined immunodeficient mice implanted with GRP-autocrine LNCaP cells. This xenograft model shows autocrine, neuropeptide- and Src kinase-mediated progression of androgen-independent CaP postcastration, and is potentially useful for testing novel therapeutic agents.
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Affiliation(s)
- Joy C Yang
- Department of Urology and Biological Chemistry, School of Medicine, University of California at Davis, Sacramento, CA 95817, USA
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Jensen RT, Battey JF, Spindel ER, Benya RV. International Union of Pharmacology. LXVIII. Mammalian bombesin receptors: nomenclature, distribution, pharmacology, signaling, and functions in normal and disease states. Pharmacol Rev 2008; 60:1-42. [PMID: 18055507 PMCID: PMC2517428 DOI: 10.1124/pr.107.07108] [Citation(s) in RCA: 395] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mammalian bombesin receptor family comprises three G protein-coupled heptahelical receptors: the neuromedin B (NMB) receptor (BB(1)), the gastrin-releasing peptide (GRP) receptor (BB(2)), and the orphan receptor bombesin receptor subtype 3 (BRS-3) (BB(3)). Each receptor is widely distributed, especially in the gastrointestinal (GI) tract and central nervous system (CNS), and the receptors have a large range of effects in both normal physiology and pathophysiological conditions. The mammalian bombesin peptides, GRP and NMB, demonstrate a broad spectrum of pharmacological/biological responses. GRP stimulates smooth muscle contraction and GI motility, release of numerous GI hormones/neurotransmitters, and secretion and/or hormone release from the pancreas, stomach, colon, and numerous endocrine organs and has potent effects on immune cells, potent growth effects on both normal tissues and tumors, potent CNS effects, including regulation of circadian rhythm, thermoregulation; anxiety/fear responses, food intake, and numerous CNS effects on the GI tract as well as the spinal transmission of chronic pruritus. NMB causes contraction of smooth muscle, has growth effects in various tissues, has CNS effects, including effects on feeding and thermoregulation, regulates thyroid-stimulating hormone release, stimulates various CNS neurons, has behavioral effects, and has effects on spinal sensory transmission. GRP, and to a lesser extent NMB, affects growth and/or differentiation of various human tumors, including colon, prostate, lung, and some gynecologic cancers. Knockout studies show that BB(3) has important effects in energy balance, glucose homeostasis, control of body weight, lung development and response to injury, tumor growth, and perhaps GI motility. This review summarizes advances in our understanding of the biology/pharmacology of these receptors, including their classification, structure, pharmacology, physiology, and role in pathophysiological conditions.
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Affiliation(s)
- R T Jensen
- Digestive Diseases Branch, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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Shan L, Aster JC, Sklar J, Sunday ME. Notch-1 regulates pulmonary neuroendocrine cell differentiation in cell lines and in transgenic mice. Am J Physiol Lung Cell Mol Physiol 2006; 292:L500-9. [PMID: 17028268 DOI: 10.1152/ajplung.00052.2006] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The notch gene family encodes transmembrane receptors that regulate cell differentiation by interacting with surface ligands on adjacent cells. Previously, we demonstrated that tumor necrosis factor-alpha (TNF) induces neuroendocrine (NE) cell differentiation in H82, but not H526, undifferentiated small cell lung carcinoma lines. We now test the hypothesis that TNF mediates NE cell differentiation in part by altering Notch gene expression. First, using RT-PCR, we determined that TNF treatment of H82, but not H526, transiently decreases notch-1 mRNA in parallel with induction of gene expression for the NE-specific marker DOPA decarboxylase (DDC). Second, we treated H82 and H526 with notch-1 antisense vs. sense oligodeoxynucleotides. Using quantitative RT-PCR and Western analyses we demonstrate that DDC mRNA and protein are increased in H82 by notch-1 antisense, whereas notch-1 mRNA and activated Notch-1 protein are decreased. mRNA for Hes1, a transcription factor downstream from activated Notch, is also decreased by Notch-1 antisense in H82 but not H526. After 7 days of Notch-1 antisense treatment, neural cell adhesion molecule (NCAM) immunoreactivity is induced in H82 but not H526. Third, we generated transgenic mice bearing notch-1 driven by the neural/NE-specific calcitonin promoter, which express activated Notch-1 in developing lung epithelium. Newborn NotchCal mouse lungs have high levels of hes1 mRNA, reflecting increased activated Notch, compared with wild-type. NotchCal lungs have decreased CGRP-positive NE cells, decreased protein gene product 9.5 (PGP9.5)-positive NE cells, and decreased gastrin-releasing peptide (GRP), CGRP, and DDC mRNA levels compared with normal littermates. Cumulatively, these observations provide further support for a role for Notch-1 signaling in regulating pulmonary NE cell differentiation.
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MESH Headings
- Animals
- Animals, Newborn
- Calcitonin/genetics
- Carcinoma, Small Cell/genetics
- Carcinoma, Small Cell/pathology
- Cell Differentiation/drug effects
- Cell Line, Tumor
- Dopa Decarboxylase/genetics
- Gastrin-Releasing Peptide/genetics
- Gastrin-Releasing Peptide/metabolism
- Gene Expression/drug effects
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Lung/cytology
- Lung/drug effects
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Mice
- Mice, Transgenic
- Neural Cell Adhesion Molecules/metabolism
- Neurosecretory Systems/cytology
- Neurosecretory Systems/drug effects
- Oligonucleotides, Antisense/pharmacology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Notch1/genetics
- Receptor, Notch1/metabolism
- Signal Transduction/drug effects
- Tumor Necrosis Factor-alpha/pharmacology
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Affiliation(s)
- Lin Shan
- Department of Pathology, Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Gu Q, Lee LY. Sensitization of pulmonary chemosensitive neurons by bombesin-like peptides in rats. Am J Physiol Lung Cell Mol Physiol 2005; 289:L1104-12. [PMID: 16040630 PMCID: PMC1783972 DOI: 10.1152/ajplung.00163.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Small cell lung cancer (SCLC) patients suffer from pulmonary stresses such as dyspnea and chest pain, and the pathogenic mechanisms are not known. SCLC cells secrete a variety of bioactive neuropeptides, including bombesin-like peptides. We hypothesize that these peptides may enhance the sensitivity of the pulmonary chemosensitive nerve endings, contributing to the development of these pulmonary stresses in SCLC patients. This study was therefore carried out to determine the effects of bombesin and gastrin-releasing peptide (GRP), a major bombesin-like peptide, on the sensitivities of pulmonary chemoreflex and isolated pulmonary vagal chemosensitive neurons. In anesthetized, spontaneously breathing rats, intravenous infusion of bombesin or GRP significantly amplified the pulmonary chemoreflex responses to chemical stimulants such as capsaicin and ATP. The enhanced responses were completely abolished by perineural capsaicin treatment of both cervical vagi, suggesting the involvement of pulmonary C-fiber afferents. In isolated pulmonary vagal chemosensitive neurons, pretreatment with bombesin or GRP potentiated the capsaicin-induced Ca(2+) transient. This sensitizing effect was further demonstrated in patch-clamp recording studies; the sensitivities of these neurons to both chemical (capsaicin and ATP) and electrical stimuli were significantly enhanced by the presence of either bombesin or GRP. In summary, our results have demonstrated that bombesin and GRP upregulate the pulmonary chemoreflex sensitivity in vivo and the excitability of isolated pulmonary chemosensitive neurons in vitro.
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Affiliation(s)
- Qihai Gu
- Dept. of Physiology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA
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Subramaniam M, Sugiyama K, Coy DH, Kong Y, Miller YE, Weller PF, Wada K, Wada E, Sunday ME. Bombesin-like peptides and mast cell responses: relevance to bronchopulmonary dysplasia? Am J Respir Crit Care Med 2003; 168:601-11. [PMID: 12807697 DOI: 10.1164/rccm.200212-1434oc] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bombesin-like peptides (BLPs) are elevated in newborns who later develop bronchopulmonary dysplasia (BPD). In baboon models, anti-BLP blocking antibodies abrogate BPD. We now demonstrate hyperplasia of both neuroendocrine cells and mast cells in lungs of baboons with BPD, compared with non-BPD controls or BLP antibody-treated BPD baboons. To determine whether BLPs are proinflammatory, bombesin was administered intratracheally to mice. Forty-eight hours later, we observed increased numbers of lung mast cells. We analyzed murine mast cells for BLP receptor gene expression, and identified mRNAs encoding bombesin receptor subtype 3 and neuromedin-B receptor (NMB-R), but not gastrin-releasing peptide receptor. Only NMB-R-null mice accumulated fewer lung mast cells after bombesin treatment. Bombesin, gastrin-releasing peptide, NMB, and a bombesin receptor subtype 3-specific ligand induced mast cell proliferation and chemotaxis in vitro. These observations support a role for multiple BLPs in promoting mast cell responses, suggesting a mechanistic link between BLPs and chronic inflammatory lung diseases.
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Affiliation(s)
- Meera Subramaniam
- Brigham and Women's Hospital, Department of Pathology, 75 Francis Street, Boston, MA 02115, USA
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Abstract
Despite extensive effort in improvement of diagnosis and treatment of patients with lung cancer in past three decades, the overall survival of patients with the disease remains dismal. Because the development of lung cancer takes a few decades, early diagnosis of the disease or identification of truly high-risk populations may provide us opportunity to successfully cure or prevent the disease. Recent advances in understanding biological basis of lung tumorigenesis provide new tools for detecting malignant cells or the process of malignant transformation and progression. Along with identification of molecular abnormalities in the early lung tumorigenesis, advanced molecular analytic technologies have been emerged, which may facilitate development of rapid and effective methods for early diagnosis and risk assessment. Here, I discuss recent progresses in understanding of early molecular abnormalities in lung cancer, efforts of translating laboratory findings to clinical tests, and prospective of biomarkers in lung cancer diagnosis and risk assessment.
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Affiliation(s)
- Li Mao
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
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12
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Mao L. Molecular abnormalities in lung carcinogenesis and their potential clinical implications. Lung Cancer 2001; 34 Suppl 2:S27-34. [PMID: 11720738 DOI: 10.1016/s0169-5002(01)00341-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Development of lung cancer is multistep and requires accumulation of multiple genetic and epigenetic alterations. Modern molecular technology has facilitated a rapid and effective identification of these genetic alterations as well as epigenetic alterations. The determination of molecular alterations in the early tumorigenic process of the lung will not only extend our understanding of the underlying biology but also provide molecular markers for cancer risk assessment, early detection, and molecular classification. In this article, I will discuss the common molecular abnormalities in lung cancer and how these abnormalities may be used as biomarkers in clinical practice.
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Affiliation(s)
- L Mao
- The University of Texas M.D. Anderson Cancer Center, FC9.3014, 1515 Holcombe Blvd, Houston, TX 77030, USA.
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Cullen A, Emanuel RL, Torday JS, Asokananthan N, Sikorski KA, Sunday ME. Bombesin-like peptide and receptors in lung injury models: diverse gene expression, similar function. Peptides 2000; 21:1627-38. [PMID: 11090916 DOI: 10.1016/s0196-9781(00)00294-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We previously demonstrated that bombesin-like peptide (BLP) mediates lung injury in premature infants with bronchopulmonary dysplasia (BPD). We now investigate gene expression and function of BLP (gastrin-releasing peptide, GRP) and BLP-receptors (GRP-R and BRS-3) in lung from two baboon BPD models. In the "interrupted gestation model," only GRP mRNA was up-regulated. In the "hyperoxic model," GRP-R mRNA was up-regulated. In lung explants from O2-treated animals, all BPD animals responded to 1nM bombesin, whereas non-BPD animals did not; the opposite effect was observed with a BLP blocking antibody. Cumulatively, these observations suggest that novel BLPs and/or BLP receptors are likely to be implicated in the pathogenesis of BPD.
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Affiliation(s)
- A Cullen
- Department of Medicine, Division of Neonatology, Children's Hospital and Harvard Medical School, Boston, MA, USA
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Sun B, Schally AV, Halmos G. The presence of receptors for bombesin/GRP and mRNA for three receptor subtypes in human ovarian epithelial cancers. REGULATORY PEPTIDES 2000; 90:77-84. [PMID: 10828496 DOI: 10.1016/s0167-0115(00)00114-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bombesin-like peptides can function as autocrine or paracrine growth factors and stimulate the growth of various cancers. The antagonists of bombesin/gastrin-releasing peptide (GRP) suppress the proliferation of diverse tumors including ovarian cancer by mechanisms likely mediated by bombesin receptors. In this study, we used the reverse transcription-polymerase chain reaction (RT-PCR) method to evaluate the mRNA expression of three bombesin receptor subtypes: gastrin-releasing peptide receptor (GRPR), neuromedin B receptor (NMBR), and bombesin receptor subtype 3 (BRS-3), in 22 specimens of human epithelial ovarian cancer and in two human ovarian cancer lines. Of the 22 ovarian cancer specimens analyzed, 17 tumors ( approximately 77%) expressed mRNA for GRPR, 19 ( approximately 86%) showed NMBR mRNA and six ( approximately 27%) revealed BRS-3 mRNA. Thus, 14 of 22 specimens ( approximately 64%) expressed mRNAs for both GRPR and NMBR, and five ( approximately 23%) expressed all three subtypes. The expression of GRPR appeared to be greater in poorly differentiated ovarian carcinomas. A higher incidence of BRS-3 expression was observed in samples with tumor Stage IV (4/4, 100%) compared with Stage III (1/17, approximately 6%). mRNA for both GRPR and NMBR was also detected in OV-1063 and UCI-107 human ovarian cancer xenografts, but BRS-3 was found only in OV-1063, which originated from a metastatic tumor. In addition, functional receptors for bombesin/GRP were found in eight of 11 ovarian cancer specimens investigated and in both ovarian cancer lines by receptor binding assay. Our study indicates that GRPR and NMBR are widely distributed in human ovarian carcinomas with BRS-3 being found in Stage IV tumors. Some approaches based on bombesin/GRP receptor antagonists or targeted bombesin analogs could be considered for treatment of ovarian cancers.
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Affiliation(s)
- B Sun
- Endocrine Polypeptide and Cancer Institute, Veterans Affairs Medical Center, 1601 Perdido Street, 70112-1262, New Orleans, LA, USA
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15
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Abstract
The upper aerodigestive tract is predisposed to the formation of multiple primary tumors due to field cancerization. TGF-alpha/EGFR autocrine signaling appears to play an important role in squamous cell carcinoma of the head and neck (SCCHN) and upregulation of TGF-alpha and EGFR is an early event in SCCHN carcinogenesis. STAT proteins, including Stat3, are activated by TGF-alpha and EGFR and strategies that downmodulate TGF-alpha or EGFR inhibit SCCHN cell proliferation and abrogate Stat3 activation. Targeting Stat3 leads to SCCHN growth inhibition, increases apoptosis and a downmodulation of Bcl-xL expression in head and neck tumors. These studies support the role of Stat3 as an oncogene, which is activated early in SCCHN carcinogenesis, and efforts to understand EGFR-mediated Stat3 signaling could facilitate novel strategies that will interfere with this growth promoting pathway. Oncogene (2000).
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Affiliation(s)
- J I Song
- Department of Otolaryngology, University of Pittsburgh School of Medicine and The University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, PA 15213, USA
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16
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Sun B, Halmos G, Schally AV, Wang X, Martinez M. Presence of receptors for bombesin/gastrin-releasing peptide and mRNA for three receptor subtypes in human prostate cancers. Prostate 2000; 42:295-303. [PMID: 10679759 DOI: 10.1002/(sici)1097-0045(20000301)42:4<295::aid-pros7>3.0.co;2-b] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Bombesin-like peptides can function as autocrine or paracrine growth factors and stimulate the growth of some cancer cells, including human prostate cancer. Three bombesin receptor subtypes, termed gastrin-releasing peptide receptor (GRPR), neuromedin B receptor (NMBR), and bombesin receptor subtype 3 (BRS-3), have been identified in rodents and humans. METHODS We investigated the presence and characteristics of the functional receptors for bombesin/GRP in human prostate adenocarcinoma specimens by radio-receptor assay and the mRNA expression of the three bombesin receptor subtypes by RT-PCR. RESULTS Of the 80 specimens of primary prostate cancer examined by receptor binding assays, 50 ( approximately 63%) showed high-affinity, low-capacity binding sites for bombesin/GRP, and 12 of these 50 receptor-positive specimens also showed a second binding site. Of the 22 prostate cancer specimens analyzed by RT-PCR, 20 (91%) expressed GRPR mRNA, 3 (14%) showed NMBR mRNA, and 2 ( approximately 9%) revealed BRS-3 mRNA. No correlation was observed between receptor expression and patients' age or pathological data. CONCLUSIONS The detection of a wide distribution of bombesin/GRP receptors in human prostate carcinomas supports the view that they may be involved in modulation of tumor progression and suggests that approaches based on binding of bombesin receptor antagonists or new targeted cytotoxic bombesin analogs to prostate cancers could be considered for the therapy.
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Affiliation(s)
- B Sun
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, New Orleans, Louisiana 70112, USA
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Cohen AJ, Franklin WA, Magill C, Sorenson J, Miller YE. Low neutral endopeptidase levels in bronchoalveolar lavage fluid of lung cancer patients. Am J Respir Crit Care Med 1999; 159:907-10. [PMID: 10051271 DOI: 10.1164/ajrccm.159.3.9806062] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Neutral endopeptidase (NEP) is a cell surface enzyme found in normal human lung and which hydrolyzes small bioactive peptides, some of which act as growth factors for normal and malignant airway epithelial cells. Expression of NEP varies widely in human lung tissue from different individuals. NEP is often expressed at low or undetectable levels in both small-cell and non-small-cell lung cancer, and inhibits the growth of lung cancer cell lines. Variation in the expression of NEP could be a factor in susceptibility to lung cancer. We hypothesized that NEP could be measured in bronchoalveolar lavage fluid (BALF) and that airway levels of NEP would be low in lung cancer patients as compared with normal controls. We measured NEP and total protein in cell-free BALF supernatant, and expressed the respective concentrations as a ratio. NEP levels showed wide variation in BALF of healthy volunteers. Most patients with lung cancer had no NEP detectable in BALF. The mean NEP/total protein ratio was significantly lower in patients with lung cancer (0.87 +/- 0.7 ng NEP/mg protein) than in normal healthy subjects (14.0 +/- 4.3, p < 0.0003). We conclude that NEP levels are highly variable in BALF of normal volunteers, and are low or undetectable in most BALF specimens from patients with lung cancer. Low NEP levels in the airways may be a factor in the pathogenesis of carcinoma of the lung.
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Affiliation(s)
- A J Cohen
- Department of Pathology, Denver Veterans' Administration Medical Center; University of Colorado Health Sciences Center; National Jewish Center for Medicine and Research, Denver, Colorado, USA.
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Cohen AJ, King TE, Gilman LB, Magill-Solc C, Miller YE. High expression of neutral endopeptidase in idiopathic diffuse hyperplasia of pulmonary neuroendocrine cells. Am J Respir Crit Care Med 1998; 158:1593-9. [PMID: 9817713 DOI: 10.1164/ajrccm.158.5.9712019] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Idiopathic diffuse hyperplasia of pulmonary neuroendocrine cells (IDHPNC) is a clinicopathological entity characterized by a diffuse hyperplasia of neuroendocrine cells involving distal bronchi and bronchioles. The pathogenesis of this syndrome remains unknown. The hyperplastic neuroendocrine (NE) cells contain multiple neuropeptides, including the bombesinlike peptides (BLP), which are likely important in the pathogenesis of the disorder by stimulating proliferation of fibroblasts in a paracrine fashion and the NE cells themselves in an autocrine manner. Neutral endopeptidase (NEP) is a cell-surface enzyme that hydrolyzes BLP and other bioactive peptides. Low or undetectable NEP is present in many primary lung cancers and cell lines. Low NEP expression could increase neuropeptide-induced autocrine effects by increasing local levels of neuropeptides. We hypothesized that IDHPNC was associated with low or absent NEP expression. NEP expression was assayed in patients with IDHPNC (n = 3) and was compared with expression in patients with idiopathic pulmonary fibrosis (n = 5), hypersensitivity pneumonitis (n = 5), and normal lung (n = 4) using immunohistochemistry, ELISA, activity assay, and Western blot analysis. By these assays, NEP expression was highest in lungs affected by IDHPNC. NEP mRNA, as assessed in IDHPNC lung tissue by RT-PCR, was the expected size and free of mutation between bp 238-2437. Therefore, IDHPNC is unlikely to be the result of a defect in NEP expression. The apparent increase in NEP expression in lung tissue from patients with IDHPNC may reflect a compensatory increase that partly counteracts abundant neuropeptides, including BLP, present in this disorder.
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Affiliation(s)
- A J Cohen
- Division of Pulmonary Sciences and Critical Care Medicine and the Denver Veterans Administration Medical Center, University of Colorado Health Sciences Center, Denver, Colorado, USA
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19
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Koppán M, Halmos G, Arencibia JM, Lamharzi N, Schally AV. Bombesin/gastrin-releasing peptide antagonists RC-3095 and RC-3940-II inhibit tumor growth and decrease the levels and mRNA expression of epidermal growth factor receptors in H-69 small cell lung carcinoma. Cancer 1998; 83:1335-43. [PMID: 9762934 DOI: 10.1002/(sici)1097-0142(19981001)83:7<1335::aid-cncr10>3.0.co;2-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Antagonists of bombesin/gastrin-releasing peptide (BN/GRP) have been developed to block the autocrine stimulatory effect of BN/GRP on tumors such as small cell lung carcinoma (SCLC). Although several studies have addressed the intracellular events that follow the formation of the receptor-ligand complex, the mechanism of action of BN/GRP antagonists remains unclear. METHODS In this study the authors investigated the effect of synthetic BN/GRP antagonists RC-3095 and RC-3940-II on tumor growth and the expression of epidermal growth factor receptors (EGF-R) in H-69 SCLC. Athymic nude mice xenografted with H-69 SCLC were treated subcutaneously for 5 weeks with RC-3095 and RC-3940-II at the dose of 10 microg/animal/day. RESULTS RC-3095 decreased tumor volume by approximately 50% (P < 0.05) and RC-3940-II by 70-60% (P < 0.01). Tumor burden also was significantly decreased in the groups treated with RC-3095 and RC-3940-II. Receptor analyses demonstrated high affinity binding sites for BN/GRP and EGF on the untreated H-69 SCLC tumors. After treatment with RC-3095 and RC-3940-II, the concentration of receptors for BN/GRP was decreased by 29.0% and 36.5%, respectively (both, P < 0.01) compared with controls, and EGF-R levels were reduced by 62.3% and 63.0%, respectively (both, P < 0.01). Reverse transcriptase-polymerase chain reaction and Southern blot analyses revealed that the levels of mRNA for EGF-R in tumors were lowered by 31% (P < 0.05) and 43% (P < 0.01), respectively, after treatment with RC-3095 and RC-3940-II. CONCLUSIONS This study indicates that the inhibition of growth of H-69 SCLC by BN/GRP antagonists RC-3095 and RC-3940-II is accompanied by a marked decrease in the levels and mRNA expression of EGF-R.
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Affiliation(s)
- M Koppán
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, New Orleans, Louisiana 70146, USA
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20
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Jensen-Taubman SM, Steinberg SM, Linnoila RI. Bronchiolization of the alveoli in lung cancer: pathology, patterns of differentiation and oncogene expression. Int J Cancer 1998; 75:489-96. [PMID: 9466646 DOI: 10.1002/(sici)1097-0215(19980209)75:4<489::aid-ijc1>3.0.co;2-p] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We examined the incidence and association of bronchiolization of the alveoli with non-small cell lung cancer in lung resection specimens from 2 patient groups: those with non-small cell lung cancer and those diagnosed with a variety of non-neoplastic lung conditions. We observed marked variation in bronchiolization of the alveoli morphology ranging from normal to severely atypical and developed a classification scheme based on growth pattern, cell number and cytologic criteria. Patterns of differentiation, proliferation and growth factor receptor and oncogene expression were studied using immuno-histochemical and in situ hybridization techniques. While low-grade (0-I) bronchiolization of the alveoli lesions demonstrated markers similar to normal bronchiolar epithelium, a significant decrease in the Clara cell 10 kDa protein and tubulin and an increase in surfactant protein-A expression were observed in high-grade (II-III) lesions. Focal p53 expression was detected in 2 high-grade lesions, while c-myc mRNA and cJun protein were observed in all grades. No correlation was observed between bronchiolization of the alveoli incidence and histologic tumor type. A comparison of marker expression in lesions and tumors from the same case revealed a negative correlation between cytokeratin-14 and c-erbB-2 immuno-reactivity. Only one bronchialization of the alveoli lesion was found in the non-neoplastic patient group. We conclude that up to 12% of non-small cell lung cancer resection specimens contain bronchiolization of the alveoli lesions which exhibit altered morphology and patterns of differentiation.
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Affiliation(s)
- S M Jensen-Taubman
- Department of Cell and Cancer Biology, Medicine Branch, Division of Clinical Sciences, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, USA
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21
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Abstract
This review is a critical appraisal of our current knowledge on nasal cavity carcinogenesis by nitrosamines. The pathology and pathogenesis of nitrosamine-induced tumors in the nasal cavity of rodents is summarized while controversies on the underlying molecular mechanisms are discussed in more detail. Investigations on the distribution of metabolically competent cell types, the cellular site(s) of nitrosamine metabolism, as well as reports on the cellular distribution and persistence of DNA-adducts strongly suggest that DNA-adducts formed from reactive metabolites are not immediately responsible for the genesis of nasal cavity tumors. A preexisting high proliferative ability has also been suggested as a factor rendering certain cell types more susceptible to the carcinogenic actions of nitrosamines in the nasal cavity. However, this hypothesis has been clearly rejected by more recent investigations. Recent studies have shown that nitrosamines can stimulate the secretion of growth factors via interaction with neurotransmitter receptors in the lungs and that this molecular mechanism is an important factor in determining the histological phenotype of the developing lung tumors. In light of the fact that secretory cells are the main sites of DNA-adduct accumulation and toxic lesions in the nasal cavities of nitrosamine treated rodents, it is suggested that similar mechanisms may mediate the genesis of nitrosamine-induced nasal cavity tumors.
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Affiliation(s)
- H M Schuller
- Carcinogenesis and Developmental Therapeutics Program, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071, USA
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Siegfried JM, DeMichele MA, Hunt JD, Davis AG, Vohra KP, Pilewski JM. Expression of mRNA for gastrin-releasing peptide receptor by human bronchial epithelial cells. Association with prolonged tobacco exposure and responsiveness to bombesin-like peptides. Am J Respir Crit Care Med 1997; 156:358-66. [PMID: 9279210 DOI: 10.1164/ajrccm.156.2.9608047] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Bombesin-like peptides (BLPs) are important regulators of lung development and may also act as autocrine growth factors in lung tumors. We have previously demonstrated expression of mRNA for the three BLP receptor subtypes (neuromedin B [NMB]) receptor, gastrin-releasing peptide [GRP] receptor, and bombesin receptor subtype 3 [BRS-3]) in human non-small cell lung carcinoma (NSCLC) cell lines and bronchial biopsies using the reverse transcription-polymerase chain reaction (RT-PCR; DeMichele, et al. Am. J. Respir. Cell Mol. Biol. 1994; 11:66-74). We have also previously found that growth responses to BLPs could be elicited in some, but not all, cultures of human bronchial epithelial (HBE) cells (Siegfried, et al. Anat. Rec. 1993; 236:241-247). In this report, we utilized RT-PCR to demonstrate mRNA expression of BLP receptor subtypes in cultured HBE cells and also assessed the response of these cultures to BLPs in proliferation assays. The pattern of mRNA expression was correlated with proliferative response, and the results were also analyzed in relation to smoking history and pulmonary function of the subjects studied. Our results suggest that expression of mRNA for the GRP receptor is associated with a long smoking history (> 25 pack-years [PY], p = 0.02). This association was related to past tobacco exposure, regardless of whether the subjects were still active smokers at the time of tissue procurement. Responsiveness to GRP and NMB in proliferation assays was also found only in those HBE cultures with expression of mRNA for at least one of the known receptors for BLPs, and there was a significant association between expression of mRNA for the GRP receptor and proliferative response to both GRP and NMB (p = 0.048). HBE cultures from subjects with a greater than 25 PY smoking history were also more likely to respond to BLPs in the proliferation assays than cells from subjects with less than a 25 PY history (10 of 16 versus 1 of 7, p = 0.06). Cultures of HBE cells from four of the five subjects with severe obstructive lung disease gave a positive response to GRP and NMB in proliferation assays, compared to five of fifteen without severe obstructive lung disease, but this difference was not significant (p = 0.13). These results suggest there is an increased likelihood of expression of the GRP receptor mRNA in the respiratory epithelium of some individuals with a history of prolonged tobacco exposure, and that expression of the GRP receptor mRNA is accompanied by responsiveness to the mitogenic effects of BLPs. These effects appear to persist after smoking cessation.
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Affiliation(s)
- J M Siegfried
- Department of Pharmacology, University of Pittsburgh, Pennsylvania 15213, USA.
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Abstract
This paper summarizes current knowledge and advances speculation about the formation of the neuroendocrine system of mammalian lungs (comprising uninnervated solitary and clustered small-granule cells and innervated neuroepithelial bodies). It relates the initial appearance of neuroendocrine cells to regulation of mitotic activity in the epithelium during the development of the lung and pays special attention to the later in growth of nerves that converts some of them into neuroepithelial bodies, structures considered ideally adapted to function as chemoreceptors. A few original observations from ongoing immunohistochemical, electron microscopic, and analytical studies have been included here and there to point the discussion. The neuroendocrine cells are derived from undifferentiated precursors present in the endodermal pulmonary epithelium. At an early pseudoglandular stage of lung development these precursors begin to differentiate into neuroendocrine small-granule cells, commencing in the larynx and upper trachea, and expanding centrifugally into pulmonary airways almost as rapidly as these are laid down. Subsequently many of the intrapulmonary small-granule cell clusters become innervated. This event, the delayed appearance of small-granule cells synthesizing other than the dominant peptides and amines (calcitonin gene-related peptide and serotonin in rodents, gastrin-releasing peptide and serotonin in human beings), and other regional adjustments yield the population distribution present in the lungs of adults. Neuroendocrine cell precursors normally differentiate into typical serotonin- or peptide-synthesizing small-granule cells without requiring direct contact by nerves, and dissociated cells from a previously innervated population continue to exhibit physiological characteristics of oxygen sensors despite the loss of contact with nerves. Development of the innervation occurs in stages. Small-granule cell clusters are reached first by ganglion cells derived from pulmonary neuroblasts and later on by processes of extrinsic sensory nerves. The latter not only convey information to the central nervous system but also serve in a variety of ways to extend the neuroepithelial bodies' sphere of influence within the lung itself.
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Affiliation(s)
- S P Sorokin
- Department of Anatomy and Neurobiology, Boston University of Medicine, Massachusetts 02118, USA
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Abstract
Pulmonary neuroendocrine cells produce bioactive peptides such as gastrin-releasing peptide (GRP) at high levels in developing fetal lung. The role of GRP and other peptides in promoting branching morphogenesis, cell proliferation, and cell differentiation during lung organogenesis is reviewed. Possible roles for bioactive peptides derived from these cells in the pathophysiology of perinatal lung disorders are discussed.
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King KA, Torday JS, Sunday ME. Bombesin and [Leu8]phyllolitorin promote fetal mouse lung branching morphogenesis via a receptor-mediated mechanism. Proc Natl Acad Sci U S A 1995; 92:4357-61. [PMID: 7753811 PMCID: PMC41943 DOI: 10.1073/pnas.92.10.4357] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Pulmonary neuroendocrine cells are localized predominantly at airway branchpoints. Previous work showed that gastrin-releasing peptide (GRP), a major pulmonary bombesin-like peptide, occurred in neuroendocrine cells exclusively in branching human fetal airways. We now demonstrate that GRP and GRP receptor genes are expressed in fetal mouse lung as early as embryonic day 12 (E12), when lung buds are beginning to branch. By in situ hybridization, GRP receptor transcripts were at highest levels in mesenchymal cells at cleft regions of branching airways and blood vessels. To explore the possibility that bombesin-like peptides might play a role in branching morphogenesis, E12 lung buds were cultured for 48 hr in serum-free medium. In the presence of 0.10-10 microM bombesin, branching was significantly augmented as compared with control cultures, with a peak of 94% above control values at 1 microM (P < 0.005). The bombesin receptor antagonist [Leu13- psi(CH2NH)Leu14]bombesin alone (100 nM) had no effect on baseline branching but completely abolished bombesin-induced branching. A bombesin-related peptide, [Leu8]phyllolitorin also increased branching (65% above control values at 10 nM, P < 0.005). [Leu8]Phyllolitorin also significantly augmented thymidine incorporation in cultured lung buds. Fibronectin, which is abundant at branchpoints, induces GRP gene expression in undifferentiated cell lines. These observations suggest that BLPs secreted by pulmonary neuroendocrine cells may contribute to lung branching morphogenesis. Furthermore, components of branchpoints may induce pulmonary neuroendocrine cell differentiation as part of a positive feedback loop, which could account in part for the high prevalence of these cells at branchpoints.
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Affiliation(s)
- K A King
- Department of Pediatrics, Children's Hospital, Boston, MA, USA
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26
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Greenberger JS. The pathophysiology and management of spine metastasis from lung cancer. J Neurooncol 1995; 23:109-20. [PMID: 7543939 DOI: 10.1007/bf01053416] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- J S Greenberger
- Department of Radiation Oncology, University of Pittsburgh Medical Center, PA 15213, USA
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Li K, Nagalla SR, Spindel ER. A rhesus monkey model to characterize the role of gastrin-releasing peptide (GRP) in lung development. Evidence for stimulation of airway growth. J Clin Invest 1994; 94:1605-15. [PMID: 7929836 PMCID: PMC295320 DOI: 10.1172/jci117502] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Gastrin-releasing peptide (GRP) is developmentally expressed in human fetal lung and is a growth factor for normal and neoplastic lung but its role in normal lung development has yet to be clearly defined. In this study we have characterized the expression of GRP and its receptor in fetal rhesus monkey lung and determined the effects of bombesin on fetal lung development in vitro. By RNA blot analysis, GRP mRNA was first detectable in fetal monkey lung at 63 days gestation, reached highest levels at 80 days gestation, and then declined to near adult levels by 120 days gestation; a pattern closely paralleling GRP expression in human fetal lung. As in human lung, in situ hybridization localized GRP mRNA to neuroendocrine cells though during the canalicular phase of development (between 63-80 days gestation) GRP mRNA was present not only in classic pulmonary neuroendocrine cells, but also in cells of budding airways. Immunohistochemistry showed that bombesin-like immunoreactivity was present in neuroendocrine cells, but not in budding airways, suggesting that in budding airways either the GRP mRNA is not translated, is rapidly secreted, or a related, but different RNA is present. RNase protection analysis using a probe to the monkey GRP receptor demonstrated that the time course of receptor RNA expression closely paralleled the time course of GRP RNA expression. In situ hybridization showed that GRP receptors were primarily expressed in epithelial cells of the developing airways. Thus GRP would appear to be secreted from neuroendocrine cells to act on target cells in developing airways. This hypothesis was confirmed by organ culture of fetal monkey lung in the presence of bombesin and bombesin antagonists. Bombesin treatment at 1 and 10 nM significantly increased DNA synthesis in airway epithelial cells and significantly increased the number and size of airways in cultured fetal lung. In fact, culturing 60 d fetal lung for 5 d with 10 nM bombesin increased airway size and number nearly to that observed in cultured 80 d fetal lung. The effects of bombesin could be blocked by specific GRP receptor antagonists. Thus this study demonstrates that GRP receptors are expressed on airway epithelial cells in developing fetal lung and that the interaction of GRP with the GRP receptor stimulates airway development.
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Affiliation(s)
- K Li
- Division of Neuroscience, Oregon Regional Primate Research Center, Beaverton 97006
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Siegfried J, Han Y, DeMichele M, Hunt J, Gaither A, Cuttitta F. Production of gastrin-releasing peptide by a non-small cell lung carcinoma cell line adapted to serum-free and growth factor-free conditions. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37236-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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