gastrin-releasing-peptide and Carcinoma--Small-Cell

Several peptide hormones have been identified which alter the proliferation of lung cancer. Small cell lung cancer (SCLC), which is a neuroendocrine cancer, produces and secretes gastrin releasing peptide (GRP), neurotensin (NT) and adrenomedullin (AM) as autocrine growth factors. GRP, NT and AM bind to G-protein coupled receptors causing phosphatidylinositol turnover or elevated cAMP in SCLC cells. Addition of GRP, NT or AM to SCLC cells causes altered expression of nuclear oncogenes, such as c-fos, and stimulation of growth. Antagonists have been developed for GRP, NT and AM receptors which function as cytostatic agents and inhibit SCLC growth. Growth factor antagonists, such as the NT1 receptor antagonist SR48692, facilitate the ability of chemotherapeutic drugs to kill lung cancer cells. It remains to be determined if GRP, NT and AM receptors will served as molecular targets, for development of new therapies for the treatment of SCLC patients. Non-small cell lung cancer (NSCLC) cells also have a high density of GRP, NT, AM and epidermal growth factor (EGF) receptors. Several NSCLC patients with EGF receptor mutations respond to gefitinib, a tyrosine kinase inhibitor. Gefitinib relieves NSCLC symptoms, maintaining stable disease in patients who are not eligible for systemic chemotherapy. It is important to develop new therapeutic approaches using translational research techniques for the treatment of lung cancer patients.

Topics: Adrenomedullin; Amino Acid Sequence; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Molecular Sequence Data; Neurotensin; Peptide Hormones; Peptides

Topics: Alzheimer Disease; Biomarkers; Carcinoma, Small Cell; Chromatography, Affinity; Colipases; Diabetes Mellitus; Diagnostic Techniques, Endocrine; Enzyme Precursors; Enzyme-Linked Immunosorbent Assay; Feeding and Eating Disorders; Galanin; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Metabolic Diseases; Obesity; Protein Precursors; Radioimmunoassay; Reference Values; Reverse Transcriptase Polymerase Chain Reaction; Specimen Handling

Topics: Amino Acid Sequence; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Epidermal Growth Factor; Gastrin-Releasing Peptide; Growth Substances; Humans; Insulin-Like Growth Factor I; Lung Neoplasms; Molecular Sequence Data; Peptides

Topics: Amino Acid Sequence; Animals; Antibodies, Monoclonal; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Molecular Sequence Data; Peptides; Signal Transduction; Structure-Activity Relationship; Substance P

As we expand our knowledge of the initiators and promoters of lung cancer, early detection and intervention strategies show great potential in individuals at high risk, especially smokers and exsmokers. Documented mutations of dominant oncogenes and tumor suppressor genes in human lung cancer cells may represent important steps in the pathogenesis of invasive cancer. The precise molecular events and their sequence that lead to tumor promotion in lung cancer, however, are less well understood. Chemointervention with agents like the retinoids may halt proliferation of cancer cells prior to the development of metastatic competence. Use of anti-growth-factor therapy and peptide hormone antagonists may also have a role in intervention approaches. This paper reviews present understanding of the initiation and promotion of lung cancer, as well as preventive strategies currently proposed for patients at risk.

Topics: Carcinogens; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Gastrins; Genes, ras; Genes, Tumor Suppressor; Humans; Lung Neoplasms; Oncogenes; Peptides; Protein Processing, Post-Translational; Retinoids; Smoking; Tumor Cells, Cultured

The prevalence of neural elements in prostatic carcinoma and their effects on the behavior of the lesion have recently been recognized. Recent reports suggest that chromogranin-A- and neuron-specific enolase-expressing tumors have an earlier progression and a lower response rate to hormonal therapy. The extreme presentation of this tumor is presumed to be small cell carcinoma of the prostate. This bombesin-secreting tumor, which has a characteristic clinical picture of early visceral involvement, wide-ranging metastases, and a relatively low rate of expression of PSA and PAP, is highly responsive to chemotherapy. The relatively high rate of expression of neural elements in primary prostatic carcinoma is discordant with the low frequency of clinical small cell carcinoma of the prostate. In order to account for these differences, one can assume that neural elements may play a role in the progression of this disease by either developing their own neoplastic process (small cell carcinoma of the prostate) or, in the majority of cases, causing paracrine progression of the tumor. Bombesin is typically secreted by small cell carcinoma of the lung and possibly by the prostate. It has been shown to be a growth factor mediating the progression of this disease in a number of experiments. Preclinical data demonstrate increased invasiveness and increased proliferation associated with bombesin in the treatment of prostatic carcinoma. Based on the hypothesis that neural peptides may be important mediators of androgen-independent growth of prostatic carcinoma as well as predicting poor prognosis, inhibition of these factors may represent a therapeutic strategy of relevance for the treatment of patients with prostatic carcinoma.

Topics: Animals; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Male; Neuropeptides; Neurosecretory Systems; Peptides; Prostatic Neoplasms

Topics: Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Growth Inhibitors; Growth Substances; Humans; Lung Neoplasms; Peptides

Topics: Bombesin; Calcitonin; Calcitonin Gene-Related Peptide; Carcinoma, Small Cell; Cell Division; Gastrin-Releasing Peptide; Hormones, Ectopic; Humans; Lung Neoplasms; Peptides; Pro-Opiomelanocortin

Initial monoclonal antibody therapy trials include an attempt to control malignant proliferation of small cell lung cancer by blocking the autocrine stimulation of gastrin releasing peptide. A critical issue is the adequacy of antibody penetration into the tumor bed to effect immunologic blockade of the mitogenic peptide. The use of an indium-111 antibody chelate which is coadministered with the first therapeutic antibody administration facilitates analysis of the pharmacokinetic dynamics for this trial. If this approach is successful with gastrin releasing peptide, other peptide hormones with autocrine effects could also be targeted. A combination of anti growth factor therapies could lead to successful therapeutic control of this lethal disease.

Topics: Antibodies, Monoclonal; Carcinoma, Small Cell; ErbB Receptors; Gastrin-Releasing Peptide; Humans; Insulin-Like Growth Factor I; Lung Neoplasms; Peptides; Receptors, Transferrin

Topics: Adenocarcinoma; Biomarkers, Tumor; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; In Vitro Techniques; Lung Neoplasms; Peptides; Transforming Growth Factors

Small cell lung cancer (SCLC) is histologically simple and looks undifferentiated, but possesses cytoplasmic dense-cored granules resembling neuroendocrine granules, and frequently produces amine and peptide hormones, occasionally presenting related symptoms. Among these bioactive substances, gastrin releasing peptide (GRP) is most important, which is known as autocrine growth factor and one of the useful monitoring markers for SCLC together with neuron-specific enolase. Aromatic L-amino acid decarboxylase is another important enzyme in SCLC. Abnormality of myc family oncogenes is occasionally noted in SCLC, which appears related to proliferative activity of the tumor rather than development. Deletion of chromosomes 3p, 13q and 17p is noted in almost every SCLC, where antioncogene is suspected to be present, and inactivation of antioncogene may play an important role in development of SCLC. Nucleolar size is the important parameter for proliferative potential of SCLC. The larger the nucleoli, the faster is the growth of SCLC. Phenotypes of SCLC in vitro may be altered by change of microenvironment, although it may be due to the selective growth of a certain clone. SCLC and nervous tissue specific membrane antigen is named cluster 1 SCLC antigen, the monoclonal antibody to which will be utilized for immunohistological diagnosis, imaging and treatment of SCLC. Accumulation of basic knowledge is now leading to reconsideration of histological subtyping of SCLC.

Topics: Antibodies, Monoclonal; Aromatic-L-Amino-Acid Decarboxylases; Carcinoma, Small Cell; Cell Division; Cell Nucleolus; Chromosome Deletion; Chromosomes, Human, Pair 13; Chromosomes, Human, Pair 17; Chromosomes, Human, Pair 3; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Oncogenes; Peptide Biosynthesis

Small cell lung cancer (SCLC) cells express and secrete bombesin-like peptides (BLP) that can activate specific receptors that stimulate the growth of these cells. A murine monoclonal antibody, 2A11, which binds to the BLP, gastrin-releasing peptide with high affinity, has been reported to decrease the growth of SCLC cells in vitro and in athymic nude mice. A Phase I trial in lung cancer patients was performed using multiple doses of 2A11. Thirteen patients with lung cancer received 12 doses of 2A11 antibody three times a week for 4 weeks at one of four dose levels. Serum samples were obtained prior to initiation and before each dose of 2A11 antibody therapy for measurement of 2A11 antibody levels and determination of serum human anti-mouse antibody levels. A pilot imaging evaluation using 111In conjugated 2A11 monoclonal antibody was also performed in the same patients to aid in the study of pharmacokinetics and biodistribution. No toxic reactions were observed, and none of the patients developed detectable human antimouse antibody; however, no objective antitumor responses were observed. The mean trough serum 2A11 levels in patients increased with increasing dose level: 0.26+/-0.2 microg/ml, 6.7+/-6 microg/ml, 71.5+/-60 microg/ml, 248+/-184 microg/ml for dose levels 1 mg/m2, 10 mg/m2, 100 mg/m2, and 250 mg/m2, respectively. At each dose level, sustained detectable serum levels of the monoclonal antibody were achieved. Tumor uptake was noted in 11 of 12 patients who were injected with 111In conjugated 2A11. Because no dose-limiting clinical toxicity was observed, a mathematical model was used to define the recommended Phase II dose of 250 mg/m2. This trial established that repeated doses of monoclonal antibody 2A11 could be given safely to patients, and sustained levels could be achieved for a 4-week schedule. Further evaluation of the antitumor effects of 2A11 is warranted.

Topics: Animals; Antibodies, Monoclonal; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Humans; Immunoglobulin G; Indium Radioisotopes; Lung Neoplasms; Male; Mice; Radioimmunodetection

Two different clinical trials using biological agents directed against an autocrine growth factor and a surface marker of neuroendocrine differentiation have been used for patients with relapsed small-cell lung cancer. In a phase II trial, an antibody (2A11) directed against the autocrine growth factor gastrin-releasing peptide has been used to treat patients with relapsed small-cell lung cancer. One of 12 evaluable patients treated with 2A11 250 mg/m2 three times weekly for 4 weeks achieved a complete response. An antibody directed against the neural cell adhesion molecule has been linked to a modified ricin molecule. This immunotoxin, N901-bR, has undergone phase I testing, and a recommended phase II dose of 30 micrograms/kg/day for 7 days by continuous infusion has been determined. In the phase I trial, one of 21 patients with relapsed or refractory small-cell lung cancer had a partial response to this treatment. Therefore, it appears that an antibody directed against an autocrine growth factor and an immunotoxin directed against a surface marker of neuroendocrine differentiation can inhibit the growth of small-cell lung cancer in vitro and in vivo; both produced some evidence of antitumor activity in patients. Further studies with agents directed against autocrine growth factors and surface markers of neuroendocrine differentiation appear warranted.

Topics: Antibodies, Monoclonal; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Humans; Immunoconjugates; Immunotoxins; Lung Neoplasms; Male; Neural Cell Adhesion Molecules; Radiography; Ricin

Small cell lung cancer (SCLC) cells express and secrete gastrin-releasing peptide (GRP) which binds to receptors and stimulates growth of these cells. A murine monoclonal antibody, 2A11, which binds GRP with high affinity, decreased growth of SCLC cells in vitro and in athymic nude mice. A phase 1 trial and pharmacokinetic modeling in patients with lung cancer has defined the phase 2 dose of 2A11 but the antitumor activity in patients is unknown.. Thirteen patients with previously treated SCLC received 2A11 at 250 mg/m2 over 1 h three times per week for 4 weeks. Serum GRP, urine GRP, serum levels of 2A11, and human antimouse antibodies (HAMA) were determined.. One of 12 (8%; 95% confidence interval, 0 to 38%) evaluable patients had complete resolution of radiographically detectable tumor lasting 4 months. Four patients (33%) had stable disease. No toxic reactions were observed. The pretreatment serum GRP level of the responding patient was 3.1 fmol/mL and the median of nine nonresponding patients was 7.3 fmol/mL (range, <1.0 to 29.0). The mean trough serum 2A11 level was 49+/-18 microg/mL in the responding patient and 32 to 487 mg/mL (median, 117) in 10 nonresponding patients. HAMA did not increase during 2A11 administration in any patient.. Interruption of the GRP autocrine growth factor loop with 2A11 results in clinical antitumor activity in a minority of patients with previously treated SCLC. Further evaluation of the antitumor effects of 2A11 is warranted to define characteristics associated with response to 2A11.

Topics: Animals; Antibodies, Monoclonal; Bombesin; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Middle Aged; Peptides

Topics: Antibodies, Monoclonal; Antibody Formation; Bombesin; Carcinoma, Small Cell; Clinical Trials as Topic; Drug Evaluation; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides

Small cell lung cancer accounts for approximately 20% of new cases of lung cancer, and advanced disease is prevalent at the time of diagnosis. Neuron-specific enolase (NSE) has been the primary tumor marker in small cell lung cancer but it has relatively low sensitivity in early-stage disease. Progastrin-releasing peptide (proGRP) is a promising alternative or complementary marker for NSE. We have previously described a time-resolved immunofluorometric assay (TR-IFMA) for proGRP that lacked the necessary sensitivity and robustness for use in the routine clinical laboratory. Herein we describe the development of an improved assay using a novel monoclonal antibody pair.. Mice were immunized with different conjugated proGRP peptides, including residues 31-98, 1-98, and preproGRP(-23-125). Pair combinations of the resulting monoclonal antibodies (mAb) were tested. The improved TR-IFMA was compared with the only other available proGRP assay, the proGRP ELISA (IBL).. A panel of 12 high-affinity mAbs was produced. The best assay combination was between our original E146 mAb as solid-phase antibody and the new mAb M16 as tracer. The new TR-IFMA had a linear dose-response curve, a wide dynamic range (13-13 500 ng/L), and a limit of detection of 2.8 ng/L. Total CV was <5.6% over the whole measuring range. Bland-Altman difference analysis indicated a significant positive bias between the IFMA and the ELISA.. We describe a sensitive and robust mAb-based TR-IFMA for proGRP. The assay is fully automated and displays high quality performance.

Topics: Animals; Antibodies, Monoclonal; Autoanalysis; Biomarkers, Tumor; Carcinoma, Small Cell; Enzyme-Linked Immunosorbent Assay; Female; Fluoroimmunoassay; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Mice; Mice, Inbred BALB C; Phosphopyruvate Hydratase; Protein Precursors

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.

Topics: Animals; Animals, Newborn; Calcitonin; Carcinoma, Small Cell; Cell Differentiation; Cell Line, Tumor; Dopa Decarboxylase; Gastrin-Releasing Peptide; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; Lung; Lung Neoplasms; Mice; Mice, Transgenic; Neural Cell Adhesion Molecules; Neurosecretory Systems; Oligonucleotides, Antisense; Receptor, Notch1; RNA, Messenger; Signal Transduction; Tumor Necrosis Factor-alpha

Pro-gastrin-releasing peptide (ProGRP) is used as a specific diagnostic marker for small cell lung cancer (SCLC), a rapidly growing neoplasm with high mortality. Our object was to develop an LC-MS method for the detection and quantification of ProGRP in human serum using the specific tryptic digestion product NLLGLIEAK (m/z 485.8 for [M + 2H](2+)). For this purpose the sample pretreatment, clean-up, enrichment, and LC-MS conditions were evaluated. Sample pretreatment was carried out using ACN precipitation to decrease the sample complexity. Although ProGRP (31-98) standards were soluble in 99% ACN, it showed that optimal signal intensities were obtained by adding ACN to the serum in a 1:1 ratio v/v. A simplified tryptic digest protocol was carried out using 100 mM triethanolamine buffer to ensure pH stability during the whole procedure. The simplified protocol also includes omission of reducing and alkylating reagents. Necessary additional sample clean-up was achieved by trapping NLLGLIEAK on a RAM column (ADS-C8) which was back-flushed onto the analytical BioBasic C8 column. Volume of injection, sample enrichment, and column capacity are among the factors optimized to reach a mass LOD of 150 pg on column (OC) ProGRP (31-98). Detection of ProGRP in the serum sample of a patient suffering from SCLC with a clinically relevant concentration shows the potential of the method in diagnosis, prognosis, and monitoring of the disease.

Topics: Amino Acid Sequence; Biomarkers; Carcinoma, Small Cell; Chromatography, Liquid; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Protein Precursors; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization

The insulinoma-associated 1 (INSM1) gene is expressed exclusively during early embryonal development, but has been found re-expressed at high levels in neuroendocrine tumors. The regulatory region of the INSM1 gene is therefore a potential candidate for regulating expression of a therapeutic gene in transcriptionally targeted cancer gene therapy against neuroendocrine tumors. We analyzed expression of a reporter gene from a 1.7 kb region of the INSM1 promoter in a large number of small-cell lung cancer (SCLC) cell lines. This INSM1 promoter region showed very high levels of expression in most of the SCLC cell lines and expression was absent in cell lines of non-neuroendocrine origin. Inclusion of the general transcriptional enhancer from SV40 compromised the specificity of the promoter and did not enhance transcription in most of the SCLC cell lines. For comparison, the region of the gastrin releasing peptide (GRP) previously suggested for SCLC gene therapy was analyzed in a similar manner. High expression was observed for a number of cell lines, but unlike for the INSM1 promoter, reporter gene expression from the GRP promoter did not correlate to the relative GRP mRNA levels, demonstrating that this region may not contain all necessary regulatory elements. Expression of the suicide gene herpes simplex virus thymidine kinase (HSV-TK) from the INSM1 promoter in combination with treatment with the prodrug ganciclovir (GCV) caused a significant increase in GCV sensitivity specifically in INSM1-expressing cell lines. The INSM1 promoter is therefore a potential novel tool for transcriptionally targeted gene therapy for neuroendocrine tumors.

Topics: Antiviral Agents; Carcinoma, Small Cell; Cell Line, Tumor; Cell Survival; DNA-Binding Proteins; Dose-Response Relationship, Drug; Ganciclovir; Gastrin-Releasing Peptide; Gene Expression Regulation, Neoplastic; Genes, Reporter; Genetic Therapy; Humans; Luciferases; Lung Neoplasms; Promoter Regions, Genetic; Repressor Proteins; RNA, Messenger; Simian virus 40; Simplexvirus; Thymidine Kinase; Transfection

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.

Topics: Animals; Bombesin; Capsaicin; Carcinoma, Small Cell; Cells, Cultured; Chemoreceptor Cells; Dyspnea; Gastrin-Releasing Peptide; Gastrointestinal Agents; Humans; Lung; Neurotransmitter Agents; Nodose Ganglion; Rats; Rats, Sprague-Dawley; Respiration; Signal Transduction

It is well known that small cell neuroendocrine carcinoma (SNEC) arising at extrapulmonary sites has a poor prognosis and an interesting biological characterization. To understand biological characterization and elucidation of the origin of the histogenesis of SNEC, we report the establishment of a new SNEC cell line and characteristics of neuroendocrine properties including neuronal differentiation by treatment with dibutyryl cyclic AMP (db-cAMP).. We established a new cell line (SNEC-MI) derived from SNEC of the maxillary sinus by a modified spill-out method, and verified neuroendocrine properties including neuronal differentiation by immunocytochemical and immunoblotting methods.. The established cell line showed spherical or spindle shape in monolayer culture and was positive for neuron-specific enolase (NSE), neuronal cell adhesion protein (N-CAM, CD56) and gastrin-releasing peptide. NSE was also demonstrated in the cultured medium and dense-core neuroendocrine granules were detected ultrastructurally in the cytoplasm. Treatment of cells with db-cAMP markedly induced the development and elongation of neuronal processes, which formed a netlike arrangement. Characterization of these elongated neuronal processes revealed them immunoreacting intensely with high molecular-weight neurofilament, and a time-dependent increase of microtubule-associated protein-2 in cell lysates.. These findings indicated that this cell line possesses the capability to differentiate into neuronal cells, and supported the hypothesis that extrapulmonary SNEC might be derived from a pluripotent stem cell.

Topics: Animals; Blotting, Western; Bucladesine; Carcinoma, Neuroendocrine; Carcinoma, Small Cell; Cell Adhesion Molecules; Cell Differentiation; Cell Line, Tumor; Chromosome Aberrations; DNA, Neoplasm; Gastrin-Releasing Peptide; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Lymphatic Metastasis; Maxillary Sinus Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Neurons; Phenotype; Phosphopyruvate Hydratase; Polymerase Chain Reaction

Topics: Bombesin; Carcinoma, Small Cell; Dexamethasone; Gastrin-Releasing Peptide; Glucocorticoids; Humans; Lung Neoplasms; Zollinger-Ellison Syndrome

[Arg(6),D-Trp(7,9),N(me)Phe(8)]-substance P (6-11) (SP-G) is a novel anticancer agent that has recently completed phase I clinical trials. SP-G inhibits mitogenic neuropeptide signal transduction and small cell lung cancer (SCLC) cell growth in vitro and in vivo. Using the SCLC cell line series GLC14, 16 and 19, derived from a single patient during the clinical course of their disease and the development of chemoresistance, it is shown that there was an increase in responsiveness to neuropeptides. This was paralleled by an increased sensitivity to SP-G. In a selected panel of tumour cell lines (SCLC, non-SCLC, ovarian, colorectal and pancreatic), the expression of the mitogenic neuropeptide receptors for vasopressin, gastrin-releasing peptide (GRP), bradykinin and gastrin was examined, and their sensitivity to SP-G tested in vitro and in vivo. The tumour cell lines displayed a range of sensitivity to SP-G (IC(50) values from 10.5 to 119 microM). The expression of the GRP receptor measured by reverse transcriptase-polymerase chain reaction, correlated significantly with growth inhibition by SP-G. Moreover, introduction of the GRP receptor into rat-1A fibroblasts markedly increased their sensitivity to SP-G. The measurement of receptor expression from biopsy samples by polymerase chain reaction could provide a suitable diagnostic test to predict efficacy to SP-G clinically. This strategy would be of potential benefit in neuropeptide receptor-expressing tumours in addition to SCLC, and in tumours that are relatively resistant to conventional chemotherapy.

Topics: Animals; Antineoplastic Agents; Bradykinin; Calcium; Carcinoma, Small Cell; Cell Division; DNA, Neoplasm; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Female; Fibroblasts; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Mice; Mice, Nude; Peptide Fragments; Rats; Receptors, Bombesin; Receptors, Neuropeptide; Substance P; Transplantation, Heterologous; Tumor Cells, Cultured; Vasopressins

The objectives of this study were to investigate the effect of antisense (AS) oligodeoxynucleotides (ODNs) directed against gastrin releasing peptide (GRP) receptor mRNA on proliferation of human small cell lung cancer (SCLC) NCI-H345 cells which express the autocrine system for GRP. The methods used were to expose human SCLC cell lines to antisense ODNs or sense ODNs and to measure their proliferation by spectrophotometric assay or viable cell counts. Our results demonstrated that the single or combined AS ODNs against GRP receptor inhibited proliferation of human SCLC NCI-H345 cells significantly by 37% (P<0.01), but did not inhibit proliferation of either human bronchial epithelial BEAS 2B cells or human SCLC NCI-N417 cells, neither of which express the GRP autocrine system. The sense controls did not significantly inhibit proliferation compared with no treatment controls. Specificity was also demonstrated by the observation that cells exposed to AS ODNs had a decrease in GRP receptor expression as measured by specific binding of 34% (P<0.01), and when all three AS ODNs were used, binding was decreased by 60% (P<0.03). Furthermore, AS ODNs decreased by 75% the maximum percentage of cells responding to GRP in an intracellular calcium release assay. Our conclusions are that antisense ODNs directed against a GRP receptor which is involved in an autocrine loop in human SCLC cells inhibited proliferation of these cells by their impact on reducing GRP receptor expression. Further development of means of increasing AS ODN specificity and effectiveness in human SCLC cell is warranted.

Topics: Carcinoma, Small Cell; Cell Division; Gastrin-Releasing Peptide; Humans; Iodine Radioisotopes; Lung Neoplasms; Oligonucleotides, Antisense; Peptides; Receptors, Bombesin; RNA, Messenger; Tumor Cells, Cultured

The clinical diagnosis of leptomeningeal metastases is often difficult to substantiate. Patients with an underlying malignancy typically present with neurologic symptoms referable to multiple levels of the neuraxis. Although most patients have an abnormal cerebrospinal fluid (CSF), less than 60% have evidence of malignant cells on cytologic examination from a single lumbar puncture, and the disease is usually advanced in patients with positive results. An elevated serum level of gastrin releasing peptide (GRP) in patients with small cell carcinoma has emerged as one of the most useful markers for disease activity.. A patient with small cell carcinoma presented with signs of meningitis and an abnormal CSF. However, the CSF gave repeatedly negative cytologic results. Hence, serum and CSF were analyzed for GRP.. The CSF GRP level was elevated by more than six orders of magnitude above the serum level. An autopsy demonstrated extensive meningeal and parenchymal brain involvement by small cell carcinoma.. The diagnosis of leptomeningeal metastases in patients with small cell carcinoma can be established by CSF GRP testing, even when cytologic examination is negative.

Topics: Biomarkers, Tumor; Carcinoma, Small Cell; Diagnosis, Differential; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Meningeal Neoplasms; Middle Aged

For specific transduction of herpes simplex virus thymidine kinase (HSV-tk) into human small-cell lung carcinoma (SCLC) cells, we explored the 5'-flanking region (-1.1 kb) of the gastrin-releasing peptide (GRP) gene as a lung cancer-specific promoter. RT-PCR analysis demonstrated expression of GRP mRNA in the SBC5 human SCLC cell line but not in the RERF human SCLC cell line, the A549 human lung adenocarcinoma cell line or the HeLa human uterine cervix epithelioid carcinoma cell line. A reporting vector containing the GRP promoter (pGL2-GRP) exhibited higher luciferase activity in SBC5 than in the other 3 cell lines. After transfecting an expression vector containing the GRP promoter-bound HSV-tk gene (pGRP-TK) into the cells, we measured their sensitivity to ganciclovir (GCV). In SBC5, pGRP-tk-transfected cells became about 100 times more sensitive to GCV than parental cells in vitro. In nude mice, tumors of pGRP-tk-transfected SBC5 regressed completely after i.p. administration of GCV. GRP promoter might be a good tool for tumor-specific transduction of suicide genes in GRP-expressing SCLC cells.

Topics: Animals; Antiviral Agents; Carcinoma, Small Cell; Cell Division; Ganciclovir; Gastrin-Releasing Peptide; Genetic Vectors; HeLa Cells; Humans; Luciferases; Lung Neoplasms; Mice; Mice, Nude; Promoter Regions, Genetic; Recombinant Fusion Proteins; Simplexvirus; Thymidine Kinase; Transfection; Transplantation, Heterologous; Tumor Cells, Cultured

A hallmark of small cell lung carcinoma (SCLC) is the expression of autocrine growth factors such as neurotensin and gastrin-releasing peptide, which bind to cellular receptors and stimulate cell division. The biological activity of autocrine growth factors requires the concurrent expression of prohormone convertases that cleave the growth factors to their active form, suggesting the expression of these genes is linked in SCLCs. RNase protection assays were used to detect the expression of autocrine growth factor and prohormone convertase mRNAs in a panel of lung cancer cell lines. These mRNAs are coexpressed in SCLC and lung carcinoid cell lines, but not in normal lung epithelium or in non-small cell lung cancers. These findings, together with earlier results from our laboratory, suggest the expression of prohormone convertases has an important role in the development and maintenance of the SCLC phenotype and that autocrine growth factor and prohormone convertase genes respond to a common transcriptional activator in SCLC.

Topics: Carcinoma, Small Cell; Furin; Gastrin-Releasing Peptide; Gene Expression; Humans; Lung Neoplasms; Neurotensin; Ribonucleases; RNA, Messenger; RNA, Neoplasm; Subtilisins; Tumor Cells, Cultured

Recently, we developed a powerful cytotoxic analogue of bombesin AN-215, in which the bombesin-like carrier peptide Gln-Trp-Ala-Val-Gly-His-Leu-psi(CH2-NH)-Leu-NH2 (RC-3094) is conjugated to a potent derivative of doxorubicin, 2-pyrrolinodoxorubicin (AN-201). Small-cell lung carcinomas (SCLCs) are known to express high levels of bombesin receptors. We evaluated whether these receptors could be used for targeting cytotoxic bombesin analogue to H-69 SCLC cells. H-69 cells were xenografted into male nude mice, which then received an intravenous injection of AN-215, cytotoxic radical AN-201, the carrier peptide RC-3094 alone or unconjugated mixture of RC-3094 and AN-201. The levels of mRNA for bombesin receptor subtypes were evaluated by reverse transcription-polymerase chain reaction. In vitro, both the analogue AN-215 and the radical AN-201 showed strong antiproliferative effects on H-69 cells, AN-215 requiring more time to exert its action at 10(-8) M concentration than AN-201. In vivo, the growth of H-69 SCLC tumours was significantly inhibited by the treatment with 200 nmol kg(-1) of AN-215, while equimolar doses of the cytotoxic radical AN-201 or the mixture of AN-201 and the carrier peptide were toxic and produced only a minor tumour inhibition as compared with control groups. mRNA for bombesin receptor subtypes 2 (BRS-2) and 3 (BRS-3) was detected in H-69 tumours. The mRNA levels for BRS-3, but not for BRS-2, were lower in the AN-215-treated tumours as compared with controls. Our results demonstrate that the cytotoxic bombesin analogue AN-215 could be considered for targeted therapy of tumours, such as SCLC, that express bombesin receptors.

Topics: Animals; Bombesin; Carcinoma, Small Cell; Cell Division; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Receptors, Bombesin; Reverse Transcriptase Polymerase Chain Reaction; Transplantation, Heterologous; Tumor Cells, Cultured

The Ewing tumor family of peripheral primitive neuroectodermal tumors (pPNETs) are characterized by chromosomal translocations leading to EWS-ETS gene fusions. These hybrid genes express chimeric proteins that are thought to act as aberrant transcription factors. We therefore used differential display-PCR to compare gene expression patterns in pPNET cell lines with those of other small round cell tumors (SRCTs) of childhood. This technique detected differential expression of sequences corresponding to human gastrin-releasing peptide (GRP) in pPNET cell lines but not in other SRCT cell lines. Subsequent Northern and reverse transcription-PCR analysis of SRCT cell lines confirmed GRP positivity in all pPNET lines tested. Of primary tumors tested by reverse transcription-PCR, GRP expression was found in 7 (44%) of 16 pPNETs but in no other primary SRCTs examined. Expression of the GRP receptor gene was demonstrable in 55% of pPNET cell lines and 25% of primary pPNET tumors but also in several other SRCTs. Radioimmunoassays and immunohistochemistry confirmed expression of bioactive GRP peptide in pPNET cell lines and primary tumors, respectively. Moreover, in vitro growth of a pPNET cell line was slowed by treatment with a GRP receptor antagonist and accelerated by a GRP receptor agonist. GRP is a known autocrine growth factor in small cell lung cancer and other neuroendocrine tumors. Its expression in pPNETs provides further evidence for a neuroectodermal histogenesis of these tumors and suggests that autocrine growth of this family of tumors may be at least partially regulated by GRP.

Topics: Artificial Gene Fusion; Base Sequence; Bone Neoplasms; Carcinoma, Small Cell; Cloning, Molecular; Gastrin-Releasing Peptide; Humans; Molecular Sequence Data; Neuroectodermal Tumors, Primitive, Peripheral; Peptides; Polymerase Chain Reaction; Protein Precursors; Receptors, Bombesin; Sarcoma, Ewing; Sarcoma, Small Cell; Tumor Cells, Cultured

We studied tumor necrosis factor (TNF)-alpha as a candidate cytokine to promote neuroendocrine cell differentiation in a nitrosamine-hyperoxia hamster lung injury model. Differential screening identified expression of the genes modulated by TNF-alpha preceding neuroendocrine cell differentiation. Undifferentiated small cell lung carcinoma (SCLC) cell lines NCI-H82 and NCI-H526 were treated with TNF-alpha for up to 2 wk. Both cell lines demonstrated rapid induction of gastrin-releasing peptide (GRP) mRNA; H82 cells also expressed aromatic-L-amino acid decarboxylase mRNA within 5 min after TNF-alpha was added. Nuclear translocation of nuclear factor-kappaB immunostaining occurred with TNF-alpha treatment, suggesting nuclear factor-kappaB involvement in the induction of GRP and/or aromatic-L-amino acid decarboxylase gene expression. We also demonstrated dense core neurosecretory granules and immunostaining for proGRP and neural cell adhesion molecule in H82 cells after 7-14 days of TNF-alpha treatment. We conclude that TNF-alpha can induce phenotypic features of neuroendocrine cell differentiation in SCLC cell lines. Similar effects of TNF-alpha in vivo may contribute to the neuroendocrine cell differentiation/hyperplasia associated with many chronic inflammatory pulmonary diseases.

Topics: Animals; Aromatic-L-Amino-Acid Decarboxylases; Biomarkers; Carcinoma, Small Cell; Cell Differentiation; Cricetinae; Cytoplasmic Granules; Gastrin-Releasing Peptide; Humans; Hyperoxia; Lung; Lung Neoplasms; Neurosecretory Systems; NF-kappa B; Nitrosamines; RNA, Messenger; Transcription, Genetic; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

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.. 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.. 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.. 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.

Topics: Animals; Anticarcinogenic Agents; Antigens, Neoplasm; Antineoplastic Agents; Blotting, Southern; Bombesin; Carcinoma, Small Cell; ErbB Receptors; Gastrin-Releasing Peptide; Lung Neoplasms; Male; Membrane Glycoproteins; Mice; Mice, Nude; Neoplasm Transplantation; Peptide Fragments; Polymerase Chain Reaction; RNA, Messenger; Transplantation, Heterologous; Tumor Cells, Cultured

The murine anti-bombesin monoclonal antibody, 2A11, has been demonstrated to inhibit growth of some small-cell lung cancer (SCLC) cells in nude mice xenografts and in a clinical trial. To determine if the expression of bombesin-like peptides (BLP) and their receptors (GRP-R and NMB-R) correlate with an in vitro response to 2A11, we measured these parameters in seven SCLC cell lines. Gastrin releasing peptide (GRP) mRNA was detected in three of seven cell lines (NCI-H69, NCI-H345, NCI-H510) and neuromedin B (NMB) mRNA was detected in all seven lines using an RNase protection assay (RPA). Immunoreactive BLP was detected in the cell pellets of all lines (range 0.11-59.90 pmol/mg protein) by a solid phase GRP radioimmunoassay (RIA) using 125I-labeled 2A11. RPA detected GRP-receptor mRNA in two cell lines (NCI-H69 and NCI-H345) and NMB-receptor in three lines (NCI-H345, NCI-H510, and NCI-H660). Reverse transcriptase-PCR confirmed the presence of receptor mRNA in these lines and detected NMB-receptor in an additional three lines (NCI-H69, NCI-H82, and NCI-H187). Calcium mobilization in response to BLP stimulation was detected in the six cell lines expressing either GRP-R or NMB-R mRNA but not in NCI-N417, which had no detectable BLP-receptor. 2A11 (5 microg/ml) inhibited colony formation by 26-61% after 2 weeks in all cell lines except NCI-N417. Thus, growth inhibition by 2A11 requires the presence of at least one BLP-receptor. These findings may be useful in selecting patients with SCLC for treatment with 2A11.

Topics: Animals; Antibodies, Monoclonal; Antineoplastic Agents; Bombesin; Carcinoma, Small Cell; Cell Division; Gastrin-Releasing Peptide; Humans; Ligands; Lung Neoplasms; Mice; Neurokinin B; Peptide Biosynthesis; Peptides; Receptors, Bombesin; RNA, Messenger; Tumor Cells, Cultured; Tumor Stem Cell Assay

We studied 90 patients with small-cell lung cancer in whom levels of Pro-GRP were abnormally high before therapy. Changes in the serum Pro-GRP level have been said to correlate strongly with therapeutic responses in patients with small-cell lung cancer. We found that changes in the serum Pro-GRP level (half-life > or = 30 vs < 30 days) were a significant prognostic factor. Multivariate analysis showed that in these patients the Pro-GRP level after therapy, Performance Status, and age were independent prognostic factors.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Middle Aged; Prognosis; Survival Rate

To assess the clinical usefulness of serum pro-gastrin-releasing peptide (Pro-GRP) as a tumor marker for small cell lung carcinoma (SCLC), we measured serum levels of Pro-GRP with a newly developed ELISA and measured serum levels of neuron-specific enolase (NSE) in 44 patients with untreated SCLC and 77 patients with untreated non-SCLC. We prospectively measured serum levels of Pro-GRP and NSE in SCLC patients after initial treatment until relapse. The sensitivity (70%) and specificity (91%) of Pro-GRP were similar to those of NSE (70 and 86%). Thirty-nine % of patients who had a partial response still had elevated serum levels of Pro-GRP at the time of restaging after initial treatment. In follow-up study, 94% of patients had elevated serum levels of Pro-GRP again at the time of relapse, whereas 37% of patients showed elevated levels of NSE. Levels of Pro-GRP increased a median of 35 (-95 to 151) days before clinical evidence of relapse was detected with successive physical examinations and imaging studies, whereas levels of NSE increased 20 (-85 to 124) days after relapse was detected (P < 0.05). Pro-GRP was helpful as a diagnostic aid and a marker for therapeutic effect and relapse in patients with SCLC, supplemented to serum NSE.

Topics: Adult; Aged; Aged, 80 and over; Carcinoma, Small Cell; Female; Follow-Up Studies; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Middle Aged; Phosphopyruvate Hydratase; Prognosis; Prospective Studies; Protein Precursors; Recurrence; Survival Analysis; Time Factors

Signal transduction pathways shared by different autocrine growth factors may provide an efficient approach to accomplish clinically significant control of lung cancer growth. In this study, we demonstrate that two autocrine growth factors activate 5-lipoxygenase action of the arachidonic acid metabolic pathway in lung cancer cell lines. Both growth factors increased the production of 5(S)-hydrooxyeicosa-6E,8Z,11Z,14Z-tetraeno ic acid (5-HETE), a major early 5-lipoxygenase metabolic product. Exogenously added 5-HETE stimulated lung cancer cell growth in vitro. Inhibition of 5-lipoxygenase metabolism by selective antagonists resulted in significant growth reduction for a number of lung cancer cell lines. Primary clinical specimens and lung cancer cell lines express the message for the 5-lipoxygenase enzymes responsible for the generation of active metabolites. In vivo evaluation demonstrated that interruption of 5-lipoxygenase signaling resulted in enhanced levels of programmed cell death. These findings demonstrate that 5-lipoxygenase activation is involved with growth factor-mediated growth stimulation for lung cancer cell lines. Pharmacological intervention with lipoxygenase inhibitors may be an important new clinical strategy to regulate growth factor-dependent stages of lung carcinogenesis.

Topics: 5-Lipoxygenase-Activating Proteins; Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Base Sequence; Carcinoma, Small Cell; Carrier Proteins; Cell Division; Gastrin-Releasing Peptide; Growth Substances; Lipoxygenase Inhibitors; Lung Neoplasms; Masoprocol; Membrane Proteins; Mice; Mice, Nude; Molecular Sequence Data; Peptides; RNA, Messenger; Signal Transduction; Somatomedins

We attempted to clarify whether serum levels of a carboxy-terminal fragment of ProGRP, ProGRP(31-98), could serve as a more accurate tumour marker in patients with SCLC than neuron-specific enolase (NSE). ProGRP(31-98) and NSE were measured retrospectively in 101 newly diagnosed untreated patients with SCLC, 111 with non-small-cell lung cancer (NSCLC) and 114 patients with non-malignant lung diseases. ProGRP(31-98) and NSE levels were determined using a sandwich enzyme-linked immunosorbent assay. Sensitivity in SCLC patients was 72.3% for ProGRP(31-98) and 62.4% for NSE. Comparing the area under curve (AUC) of 'receiver operator characteristics' of ProGRP(31-98) with that of NSE, ProGRP(31-98) was the more powerful marker in the diagnosis of SCLC (P = 0.0001). Serum levels of ProGRP(31-98) were higher in the 40 patients with extensive disease than in the 61 patients with limited disease (P = 0.0082). ProGRP(31-98) was significantly higher in patients with pure small-cell carcinoma than in patients with mixed small-cell/large-cell carcinoma (P = 0.02). In serial measurement in 16 patients responding to treatment, a high degree of correlation was noted between the decrease in serum ProGRP(31-98) levels and clinical response during the second week after treatment (P = 0.0045). These results indicate that the determination of serum ProGRP(31-98) levels plays an important role in the diagnosis and treatment of SCLC patients.

Topics: Biomarkers, Tumor; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Gastrins; Humans; Lung Neoplasms; Male; Neoplasm Metastasis; Peptides; Phosphopyruvate Hydratase; Protein Precursors

Neutral endopeptidase (NEP; CALLA, CD10, EC 3.4.24.11) is a cell surface endopeptidase that hydrolyses bioactive peptides, including the bombesin-like peptides, as well as other neuropeptides. Bombesin-like peptides and other neuropeptides are autocrine growth factors for both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Low expression of NEP has been reported in SCLC and NSCLC cell lines. NEP inhibition has been shown to increase proliferation in one cell line. To date, NEP expression has not been quantitatively evaluated in normal adult lung, SCLC or NSCLC tumors, paired uninvolved lung from the same patient, or in other pulmonary neoplasms such as mesotheliomas and carcinoids. We examined the expression of NEP in these tissues and human cell lines using immunohistochemistry, flow cytometry, enzyme activity, ELISA, Western blot, and reverse transcription (RT)-PCR. Uninvolved lung tissue from different individuals displayed considerable variation in NEP activity and protein. By immunohistochemistry, NEP expression was detectable in alveolar and airway epithelium, fibroblasts of normal lung, and in mesotheliomas, whereas it was undetectable in most SCLC, adenocarcinoma, squamous cell carcinoma, and carcinoid tumors of the lung. NEP activity and protein levels were lower in all SCLC and adenocarcinoma tumors when compared to adjacent uninvolved lung, often at levels consistent with expression derived from contaminating stroma. NEP expression and activity were reduced or undetectable in most SCLC and lung adenocarcinoma cell lines. NEP mRNA by RT-PCR was not expressed or was in low abundance in the majority of lung cancer cell lines. The majority of lung tumors did not express NEP by RT-PCR as compared with normal adjacent lung. In addition, recombinant NEP abolished, whereas an NEP inhibitor potentiated, the calcium flux generated by neuropeptides in some lung cancer cell lines, demonstrating potential physiological significance for low NEP expression. NEP, therefore, is a signal transduction and possibly a growth modulator for both SCLC and NSCLC, emphasizing the role of neuropeptides in the pathogenesis of the major histological forms of lung cancer.

Topics: Adenocarcinoma; Adult; Base Sequence; Blotting, Western; Bradykinin; Calcium; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Cell Line; DNA Primers; Enzyme Inhibitors; Gastrin-Releasing Peptide; Gene Expression; Glycopeptides; Humans; Immunohistochemistry; Lung; Lung Neoplasms; Mesothelioma; Molecular Sequence Data; Neoplasm Metastasis; Neprilysin; Peptides; Polymerase Chain Reaction; Pulmonary Alveoli; Recombinant Proteins; RNA, Messenger; Signal Transduction; Tumor Cells, Cultured

Gastrin-releasing peptide has a prominent role as a tumour marker in the diagnosis of small-cell lung carcinoma. This study was designed to assess the validity of a newly developed enzyme-linked immunosorbent assay (ELISA) for pro-gastrin-releasing peptide in patients with renal and systemic diseases.. Pro-gastrin-releasing peptide concentrations in sera from normal subjects and patients with small-cell lung carcinoma, diabetes mellitus, rheumatoid arthritis, systemic lupus erythematosus, chronic glomerulonephritis, or undialysed or dialysed chronic renal failure were measured with the TND-4 Kit, a newly developed ELISA for pro-gastrin-releasing peptide.. All of the patients with normal renal function, whether they had diabetes mellitus (n=16), rheumatoid arthritis (n=10), systemic lupus erythematosus (n=12) or chronic glomerulonephritis (n=14), had serum pro-gastrin-releasing peptide concentrations less than 46 ng/l, the upper limit in normal subjects. In contrast, 14 or 16 patients (88%) with small-cell lung carcinoma, who had normal renal function, and 25 of 26 (96%) patients with chronic renal failure on haemodialysis had serum pro-gastrin-releasing peptide concentrations greater than 46 ng/l. The highest serum pro-gastrin-releasing peptide levels in patients with chronic renal failure, before and after initiating haemodialysis were 183 and 290 ng/l respectively. Ten of 16 (63%) small-cell lung carcinoma patients had serum pro-gastrin-releasing peptide concentrations greater than 290 ng/l, the highest level in haemodialysed patients. Serum pro-gastrin-releasing peptide concentrations were also elevated in patients with chronic glomerulonephritis or diabetes mellitus when their serum creatinine concentrations were greater than 120 micromol/l. And, there was a significant correlation, y=23.5+0.15x(n=22, r=0.82, P<0.001),between serum pro-gastrin-releasing peptide (y, in ng/l) and serum creatine (x in micromol/l) concentrations in those patients with renal dysfunction. The correlation between serum pro-gastrin-releasing peptide and serum urea nitrogen concentrations was likewise significant.. The evaluation of patients as to their renal functional state may be mandatory when serum pro-gastrin-releasing peptide levels are to be applied as one of the diagnostic tools for small-cell lung carcinoma or as a marker monitoring their clinical course.

Topics: Adult; Arthritis, Rheumatoid; Biomarkers, Tumor; Carcinoma, Small Cell; Diabetes Mellitus; Enzyme-Linked Immunosorbent Assay; Female; Gastrin-Releasing Peptide; Glomerulonephritis; Humans; Kidney Diseases; Kidney Failure, Chronic; Lung Neoplasms; Lupus Erythematosus, Systemic; Male; Middle Aged; Peptides; Protein Precursors; Reference Values; Reproducibility of Results

Constitutive, unregulated autocrine growth is thought to be an important mechanism whereby cancer cells gain a proliferative advantage over nonmalignant cells. The question addressed here was whether the autocrine growth system for gastrin-releasing peptide (GRP) in human small cell lung carcinoma cells is, in fact, always expressed in a constitutive, unregulated fashion. Lag, rapid, and plateau growth states were defined for small cell lung carcinoma NCI-H345 cells based on periods during which they expressed different growth rates after plating as single cell suspensions. Immunoreactive GRP in the conditioned medium and in NCI-H345 cells harvested during each of these growth states, as well as cell DNA content, GRP mRNA expression, specific 125I-GRP uptake, specific 125I-GRP binding to solubilized membranes, and GRP and neuromedin B receptor mRNA expression by reverse transcription-PCR were analyzed. Maximal levels of GRP expression were observed during the lag growth state, with the highest concentration of immunoreactive GRP in the conditioned medium during the rapid growth state. Specific 125I-GRP uptake and binding were also highest during the lag growth state; however, GRP receptor mRNA did not significantly change. In contrast to prevailing concepts, these studies support the conclusion that the expression of the GRP autocrine growth system in NCI-H345 cells is indeed regulated. Furthermore, the components are maximally expressed before rapid growth begins, suggesting that other mechanisms are activated to support the actual proliferation.

Topics: Antibody Specificity; Base Sequence; Carcinoma, Small Cell; Cell Division; Flow Cytometry; Gastrin-Releasing Peptide; Gastrins; Gene Expression Regulation, Neoplastic; Humans; Iodine Radioisotopes; Lung Neoplasms; Peptides; Polymerase Chain Reaction; Protein Binding; Receptors, Bombesin; RNA, Messenger; Tumor Cells, Cultured

Previously, GRP receptors were characterized in small cell lung cancer cells and here non-small cell lung cancer (NSCLC) cells were investigated: (125I-Tyr4) bombesin (BN) or 125I-GRP bound with high affinity to NCI-H720 (lung carcinoid) and NCI-H1299 (large cell carcinoma) cells. Binding was specific, time dependent, and saturable. Specific (125I-Tyr4)BN binding to NCI-H1299 cells was inhibited with high affinity by GRP, BN, GRP14-27, (D-Phe6)BN6-13methyl ester, moderate affinity by NMB, and low affinity by GRP1-16. BN (10 nM) transiently elevated cytosolic calcium in a dose dependent manner. BN caused translocation of protein kinase C from the cytosol to the membrane and the translocation caused by BN was reversed by (D-Phe6)BN6-13methylester. BN stimulated arachidonic acid release and the increase caused by BN was reversed by (D-Phe6)BN6-13methylester. Using a clonogenic assay, BN stimulated the growth of NCI-H720 cells, and the number of colonies was reduced using (D-Phe6)BN6-13methylester. These data suggest that GRP receptors that are present in lung carcinoid and NSCLC cells may regulate proliferation.

Topics: Arachidonic Acid; Bombesin; Calcium; Carcinoid Tumor; Carcinoma, Large Cell; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Neoplasm Proteins; Peptides; Receptors, Bombesin

Gastrin-releasing peptide (GRP) receptor antagonists were synthesized and their ability to interact with small-cell lung cancer (SCLC) cells determined. [125I] BW1023U90, bound with high affinity (Kd = 2 nM) to a single class of sites (Bmax = 55 fmol/mg protein) using SCLC cell line NCI-H345. [125I] BW1023U90 binding was time dependent and reversible even at 37 degrees C as the ligand was minimally internalized. Specific [125I] BW1023U90 binding was inhibited with high affinity by GRP as well as bombesin (BB) but not neuromedin B (NMB). BW1023U90 inhibited the ability of BB to elevate cytosolic Ca2+ and increase the growth of SCLC cells. A BW1023U90 analogue, BW2258U89 (10 micrograms/day, SC) slowed SCLC xenograft format on in nude mice and [125I] BW 1023U90 localized to SCLC tumors 1 h after injection into nude mice. BW2258U89 (4% by weight) was placed in microspheres and slowly released over a 3-week period in nude mice bearing SCLC xenografts. The microspheres containing BW2258U89 strongly inhibited SCLC growth in vivo. A radioimmunoassay was developed for the GRP receptor antagonists and the rabbit antiserum cross-reacted totally with BW2258U89 or BW1023U90. BW2258U89 immunoreactivity (5 nM) was detected in the plasma of nude mice containing the microspheres after 1 week. These data suggest that GRP receptor antagonists bind to receptors on SCLC tumors.

Topics: Amino Acid Sequence; Animals; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Kinetics; Lung Neoplasms; Mice; Mice, Nude; Neoplasm Transplantation; Oligopeptides; Peptides; Receptors, Bombesin; Structure-Activity Relationship; Transplantation, Heterologous; Tumor Cells, Cultured

The effects of bombesin/gastrin-releasing peptide (BN/GRP) on c-fos and c-jun gene expression were investigated using small cell lung cancer (SCLC) cells. BN (10 nM) increased c-fos mRNA fivefold using NCI-H345 or NCI-H510 cells. The increase was concentration dependent with 1 nM BN half-maximally increasing c-fos mRNA. Also, the increase in c-fos mRNA caused by BN was time dependent, being maximal after 1 h and returning to basal values after 4 h. GRP and GRP(14-27) but not GRP(1-16) increased c-fos mRNA. BW2258U89 (1 microM), a GRP receptor antagonist, had no effect on basal c-fos but inhibited the increase in c-fos mRNA caused by 10 nM BN. Also, BN transiently increased c-jun mRNA twofold and the increase caused by BN was blocked by BW2258U89. These data suggest that GRP receptors may regulate nuclear oncogene gene expression in SCLC cells.

Topics: Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Gene Expression; Genes, fos; Genes, jun; Humans; Lung Neoplasms; Oligopeptides; Peptide Fragments; Peptides; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; RNA, Messenger; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

Lung cancer remains the leading cause of cancer deaths in the United States. We have developed a new immunotherapeutic approach to the treatment of small cell carcinoma of the lung (SCCL) by targeting the gastrin-releasing peptide receptor (GRP-R) expressed on the surface of these cells. Bispecific immunoconjugates were constructed by chemical fusion of a GRP analog or a GRP antagonist with monoclonal antibodies directed to the cytotoxic trigger molecules Fc gamma RI and Fc gamma RIII on various immune effector cells. We demonstrated that these bispecific immunoconjugates bound to target SCCL cells in a dose-dependent manner. In the presence of these immunoconjugates, more than 80% of SCCL cells were lysed by cytokine-activated monocytes and natural killer (NK) cells measured by a 51Cr-release assay. These data indicate that bifunctional antibodies targeting GRP may have clinical use.

Topics: Antibodies, Bispecific; Antibody-Dependent Cell Cytotoxicity; Carcinoma, Small Cell; Cytotoxicity, Immunologic; Gastrin-Releasing Peptide; Gene Expression Regulation; Humans; Immunoconjugates; Interferon-gamma; Killer Cells, Natural; Lung Neoplasms; Monocytes; Neoplasm Proteins; Peptides; Receptors, Bombesin; Receptors, IgG; Recombinant Proteins; Tumor Cells, Cultured; Tumor Stem Cell Assay

Small cell lung cancers (SCLC) and some non-small cell lung cancers (NSCLC) have neuroendocrine features which include production of a variety of neuropeptides, cell surface expression of the receptors for these peptides, and autocrine stimulation by the peptides. Previous studies showed that some peptide antagonists and anti-peptide antibodies inhibited the growth of SCLC cell lines which expressed receptors for the specific peptide. We and others showed that the heterogeneity of peptide receptor expression and responsiveness was a major potential obstacle for developing therapeutic uses of peptide antagonists. In this manuscript we evaluated the effects of 11 peptide antagonists (3 bombesin-specific, 2 cholecystokinin-specific, 1 arginine vasopressin (AVP)-specific, and 5 substance P derivatives with broad specificity) on peptide-induced calcium mobilization and growth of SCLC and NSCLC cell lines. For each antagonist, we determined the dose-response effects, specificity of peptide antagonism, and biological stability in serum using Indo-1AM-based flow cytometric assays. We found that the three bombesin antagonists, S30, SC196, and L336,175, varied in potency from 10 nM to 10 microM, varied in serum stability from 6 h to more than 24 h, and had no effect on the calcium response elicited by other peptides. None of these compounds effectively inhibited the growth of SCLC cell lines in [3H]dThd and cell growth assays in vitro. Similarly, the three cholecystokinin and AVP antagonists were highly specific for cholecystokinin and AVP, respectively, had widely varying potency, but had little inhibitory effect on SCLC growth in vitro. In contrast, the five substance P derivatives inhibited the calcium response to bombesin, AVP, bradykinin, and fetal bovine serum. None of these five antagonists were as potent as the six specific antagonists described above, but they were more effective in inhibiting the growth of SCLC cell lines in vitro. These substance P derivatives inhibited the growth of peptide-sensitive SCLC cell lines more efficiently than their inhibition of peptide-insensitive NSCLC or breast cancer cell lines. Relatively high concentrations of these substance P derivatives were required to inhibit in vitro growth, even in the absence of added peptide. It is likely that more potent broad spectrum antagonists, toxins, or radiolabeled stable antagonists will need to be developed for maximal clinical development of this type of anti-growth factor therapy.

Topics: Amino Acid Sequence; Bombesin; Bradykinin; Calcium; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Cholecystokinin; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Molecular Sequence Data; Neuropeptides; Peptides; Substance P; Tumor Cells, Cultured

We investigated the effects of our synthetic bombesin/gastrin-releasing peptide (GRP) antagonists and somatostatin analogue RC-160 on the growth of human small-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma (non-SCLC) lines in nude mice. Athymic nude mice bearing xenografts of the SCLC NCl-H69 line or non-SCLC NCl-H157 line were treated for 5 and 4 weeks, respectively, with somatostatin analogue RC-160 or various bombesin/GRP antagonists. RC-160, administered s.c. peritumorally at a dose of 100 micrograms per animal per day, inhibited the growth of H69 SCLC xenografts as shown by more than 70% reduction in tumour volumes and weights, as compared with the control group. Bombesin/GRP antagonists, RC-3440, RC-3095 and RC-3950-II, given s.c. peritumorally at a dose of 20 micrograms per animal per day, also inhibited the growth of H69 SCLC tumours. RC-3950-II had the greatest inhibitory effect and decreased tumour volume and weights by more than 80%. The growth of H-157 non-SCLC xenografts was significantly reduced by treatment with RC-160, but not with bombesin/GRP antagonist RC-3095. In mice bearing either tumour model, administration of RC-160 significantly decreased serum growth hormone and gastrin levels. Specific high-affinity receptors for bombesin and somatostatin were found on membranes of SCLC H69 tumours, but not on non-SCLC H157 tumours. Receptor analyses demonstrated high-affinity binding sites for epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I) on the membranes of H69 and H157 tumours. EGF receptors were down-regulated on H69 tumours after treatment with RC-160 and bombesin/GRP antagonists. The concentration of binding sites for EGF and IGF-I on the H157 tumours was decreased after treatment with RC-160, but bombesin/GRP antagonist RC-3095 had no effect. These results demonstrate that bombesin/GRP antagonists inhibit the growth of H-69 SCLC, but not of H-157 non-SCLC xenografts in nude mice, whereas somatostatin analogue RC-160 is effective in both tumour models. This raises the possibility that these peptide analogues could be used selectively in the treatment of various subclasses of lung cancer.

Topics: Amino Acid Sequence; Animals; Antineoplastic Agents; Binding Sites; Body Weight; Bombesin; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Cell Division; Gastrin-Releasing Peptide; Gastrins; Gonadotropin-Releasing Hormone; Growth Hormone; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Molecular Sequence Data; Neoplasm Transplantation; Peptide Fragments; Peptides; Receptors, Somatotropin; Somatostatin; Substrate Specificity; Transplantation, Heterologous

The effects of corticotropin-releasing factor (CRF) on human lung cancer cell lines was investigated. Corticotropin-releasing factor increased the cAMP levels in a dose-dependent manner; CRF (100 nM) elevated the cAMP levels approximately eleven-fold using NCI-H345 cells and increased the gastrin-releasing peptide (GRP) secretion rate by approximately 70%. Similarly, sauvagine, a structural analogue of CRF, elevated the cAMP levels with a half-maximal effective dose (ED50) of 20 nM. The increase in cAMP caused by CRF and sauvagine was reversed by alpha-helical CRF(9-41). Corticotropin-releasing factor had no effect on cytosolic calcium but stimulated [3H]arachidonic acid release from NCI-H1299 cells with an ED50 of 30 nM. The increase in [3H]arachidonic acid release caused by 100 nM CRF was significantly reversed by 1 or 10 microM alpha-helical CRF(9-41). Also, CRF stimulated the clonal growth of NCI-H345 and H720 cells and the growth increase caused by CRF was reversed by alpha-helical CRF(9-41). These data suggest that CRF may be a regulatory peptide in lung cancer.

Topics: Amphibian Proteins; Arachidonic Acid; Calcium; Carcinoma, Small Cell; Cell Division; Corticotropin-Releasing Hormone; Cyclic AMP; Cytosol; Dose-Response Relationship, Drug; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptide Fragments; Peptide Hormones; Peptides; Tumor Cells, Cultured

Gastrin-releasing peptide (GRP), the mammalian form of the amphibian peptide bombesin, may act as a growth-regulatory peptide in the lung. Cultured human bronchial epithelial (HBE) cells have previously been found to proliferate in response to GRP or bombesin. Three receptors have been identified for bombesin and its analogs, namely gastrin-releasing peptide receptor (GRPR), neuromedin B receptor (NMBR), and bombesin receptor subtype 3 (BRS-3). The human genes for these receptors have been cloned and sequenced. We used the polymerase chain reaction to detect transcripts for these three receptor subtypes in HBE cells cultured from bronchial mucosal biopsies. Primers specific for each receptor subtype were used to amplify DNA fragments from reverse-transcribed mRNA isolated from these cultures. An amplified fragment was detected for GRPR in seven of nine cases, for NMBR in six of 10 cases, and the BRS-3 in three of nine cases. We have also amplified message for NMBR in five of five fresh bronchial biopsies, but message for GRPR could not be detected. In preliminary evaluation of two biopsies, there was also no evidence of BRS-3 expression. Additionally, we have detected transcripts for GRPR and NMBR in four of seven and seven of seven cases, respectively, of cultured non-small cell lung carcinomas (NSCLC). BRS-3 expression was seen in one of seven carcinomas in culture. Identity of the amplified fragments was confirmed by restriction enzyme digestion and Southern blotting. Furthermore, GRP induced expression of the early-response gene, c-jun, in an HBE cell culture and an NSCLC cell line. GRP also promoted colony formation in the NSCLC cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Base Sequence; Bronchi; Carcinoma, Small Cell; Epidermal Growth Factor; Epithelium; Gastrin-Releasing Peptide; Gene Expression; Genes, jun; Humans; Lung Neoplasms; Molecular Sequence Data; Peptides; Polymerase Chain Reaction; Receptors, Bombesin; RNA, Messenger; Tumor Cells, Cultured

The mammalian bombesin-like peptide, gastrin-releasing peptide (GRP), is expressed by many small cell lung carcinomas (SCLC), stimulates the growth of some SCLC and thus is an autocrine growth factor for a subset of SCLC. The subset of SCLC that expresses GRP typically shows neuroendocrine differentiation and has been designated as "classic" SCLC. To begin to characterize the mechanisms responsible for the expression of GRP in classic SCLC, the 5'-flanking region of the human GRP gene was sequenced and analyzed for cis-acting elements. Constructs containing up to 6.0 kilobases of 5'-flanking region were transiently expressed in SCLC and in control cell lines. Deletion analysis demonstrated that a sequence of 178 bases upstream of the transcriptional start was sufficient for basal expression in SCLC cell lines. A negative regulatory element was located between -5.5 and -2.6 kilobases; a general enhancer element was located between -1409 and -1197 kilobases, and a tissue-specific element was located between -1128 and -793 kilobases. Mobility shift analysis indicated that proteins from nuclear extracts of classic SCLC but not variant SCLC bound to this tissue-specific regulatory element. Thus the regulation of GRP gene expression in SCLC cell lines is a balance between a negative element, a general enhancer, and a tissue-specific element that appears active only in classic SCLC cell lines.

Topics: Amino Acid Sequence; Base Sequence; Carcinoma, Small Cell; Enhancer Elements, Genetic; Gastrin-Releasing Peptide; Genes, Reporter; Humans; Lung Neoplasms; Molecular Sequence Data; Neoplasm Proteins; Peptides; RNA, Messenger; Tumor Cells, Cultured

Gastrin-releasing peptide (GRP) is a specific and an actively secreted product of small cell lung carcinoma (SCLC) cells. Based on this observation, we attempted to develop a new approach for early detection of SCLC and for monitoring therapeutic response in SCLC patients. Recombinant human ProGRP(31-98), a region common to three types of human ProGRP molecules, was synthesized, and a convenient radioimmunoassay system was developed; in this assay, the minimum detectable amount in serum was 10 pM when 0.1 ml of unextracted serum was used. Serum levels of immunoreactive ProGRP(31-98) were measured in 247 normal subjects, 180 patients with nonmalignant pulmonary diseases, 231 patients with non-SCLC, and 140 patients with SCLC. The percentages of subjects with the level greater than 10 pM in normal subjects and patients with nonmalignant pulmonary diseases and with non-SCLC were 1.2, 2.2, and 3.0%, respectively. In contrast, 76% of patients with SCLC had elevated levels; the positive rates in SCLC patients with limited and extensive diseases were 73 and 79%, respectively, indicating that the serum Pro-GRP(31-98) level could serve as a reliable tumor marker in SCLC patients, even at a relatively early stage of this disease. Moreover, changes in the serum ProGRP(31-98) showed excellent correlation with the therapeutic responses in SCLC patients. These results indicate that the determination of serum ProGRP(31-98) levels plays an important role in the diagnosis and treatment of SCLC patients.

Topics: Biomarkers, Tumor; Carcinoma, Small Cell; Chromatography, Gel; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptide Fragments; Peptides; Radioimmunoassay; Recombinant Proteins; Reference Values; Sensitivity and Specificity

Topics: Amino Acid Sequence; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Insulin-Like Growth Factor I; Lung Neoplasms; Mixed Function Oxygenases; Molecular Sequence Data; Multienzyme Complexes; Peptides; Protein Precursors; Tumor Cells, Cultured

The bombesin-like peptides comprise a large family of peptides common to both amphibians and mammals that function as growth factors, neurotransmitters, and paracrine hormones. GRP, the mammalian homolog of bombesin and its receptor, as well as NMB, the mammalian homolog of ranatensin, are expressed in human neoplasms and, in particular, in small cell lung carcinomas (SCLC). To better characterize the physiological roles of bombesin-like peptides, our laboratory has cloned the receptors for GRP in murines, rats, and humans. The 3T3 GRP receptor was isolated and characterized using the two-electrode-voltage-clamp analysis and acquorin-emission methods in xenopus oocytes expression system. The rat and human GRP and NMB receptors were cloned by hybridization at low stringency, using the mouse cDNA receptor probe. Sequence analysis of the receptors showed 384 and 390 amino acids for GRP and NMB receptors, respectively. The homology between the two receptors is 60% and between species in the same receptor, 90%. The receptors belong to the 7-membrane spanning domains superfamily. The specific GRP-R antagonist blocked the response to bombesin in oocytes injected with GRP-R, but failed to do so in oocytes injected with NMB-R. The two receptors differ in their distribution of tissue expression. RNA blot and RNase protection analysis showed the same size of mRNA without alteration in the receptors. RT + PCR analysis performed on genomic DNA revealed similarity between normal and cell DNAs, suggesting no major gene deletion or rearrangement. Southern blot analysis indicated the absence of gene amplification. Sequence analysis of the exonic segments of the receptor genes displayed identical amino acids to the respective cDNAs. None of the genes had classic TATAA box. Somatic cell hybrids localized the GRP-R on the X-chromosome and the NMB-R on chromosome 6. The same sequence of normal genes and cDNAs of GRP and NMB receptors, together with the gene characterization, demonstrated that SCLC cell lines do not require a structural change in receptor protein or genomic rearrangement.

Topics: 3T3 Cells; Amino Acid Sequence; Animals; Base Sequence; Bombesin; Brain Neoplasms; Carcinoma, Small Cell; Cloning, Molecular; Consensus Sequence; DNA; Gastrin-Releasing Peptide; Glioblastoma; Humans; Lung Neoplasms; Mice; Molecular Sequence Data; Neoplasm Proteins; Neurokinin B; Oocytes; Peptides; Rats; Receptors, Bombesin; Receptors, Neurotransmitter; Sequence Alignment; Sequence Homology, Amino Acid; Tumor Cells, Cultured; Xenopus laevis

The ligand-binding properties of the gastrin-releasing peptide (GRP) receptor and the cellular processing of GRP have been studied in the small-cell lung cancer (SCLC) cell line COR-L42. Scatchard analysis of GRP receptor expression indicated a single class of high-affinity receptors (Kd 1.5 nM) and approx. 6700 receptors/cell. GRP bound to its receptor with a Ki of 2.4 nM. The bombesin-related peptides neuromedin B (NMB) and phyllolitorin also bound to GRP receptors with Ki values of 22.7 and 59.1 nM respectively. Binding of 125I-GRP to COR-L42 cells increased rapidly at 37 degrees, achieved a maximum at 10 min and declined rapidly thereafter. At 4 degrees C, maximum binding was achieved at 30 min and the subsequent decline in cell-associated radioactivity was slower than that seen at 37 degrees C. Acid/salt extraction, to separate surface-bound ligand from internalized GRP, indicated that after receptor binding 125I-GRP was rapidly internalized. To determine the pathway of 125I-GRP degradation, binding studies were carried out with the lysosomotropic agent chloroquine (5 mM), and with phosphoramidon (10 microM), an inhibitor of the membrane-bound enzyme (EC 3.4.24.11). Both agents markedly inhibited the degradation of GRP, indicating that this process involves a lysosomal pathway and a phosphoramidon-sensitive pathway, possibly involving the EC 3.4.24.11 enzyme. GRP receptor down-regulation was observed following a 10 min exposure to 100 nM-GRP. With longer pretreatment times the number of binding sites recovered to 80% of control values. Treatment with 5 mM-chloroquine plus GRP or cycloheximide (10 micrograms/ml) plus GRP demonstrated that the majority of GRP receptors are recycled. NMB and phyllolitorin pretreatment did not influence the subsequent binding of 125I-GRP, suggesting that these peptides do not down-regulate GRP receptors.

Topics: Anti-Bacterial Agents; Binding, Competitive; Bombesin; Carcinoma, Small Cell; Cell Line; Chloroquine; Gastrin-Releasing Peptide; Glycopeptides; Humans; Kinetics; Ligands; Lung Neoplasms; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter

Strategies to block the effects of tumor growth factors, such as estrogen, and to recruit other regulatory elements, such as with retinoids, have focused interest on the possibility of successful tumor intervention approaches. Approaches that neutralize the effects of critical molecules that drive tumor promotion are attractive targets for evaluation as new intervention agents. Clinical intervention trials with early stage patients or with subjects from "high risk" populations impose stricter types of constraints than conventional chemotherapy approaches in advanced stage patients. The potential for short-term toxicity has to be considered, as it may affect subject accrual or compliance. The longer expected survival of intervention subjects mandates closer attention to the possibilities of unexpected long-term toxicities with chronic administration of an intervention agent. As part of a Phase I clinical trial evaluating the utility of a monoclonal antibody directed against the autocrine growth factor, gastrin-releasing peptide to block the growth of small cell lung cancer, we developed a mathematical model to predict the requisite amount of antibody to neutralize growth factor effect. This model requires knowledge of the equilibrium concentration of the secreted growth factor, specific receptor, and bioavailability of the antibody in the tumor interstitium. A range of possible target doses of antibody can be developed to address the potential for heterogeneity frequently encountered in such systems, including a range of levels for peptide production and specific receptor expression. This approach could be applied to rationally derive treatment or intervention in which specific information regarding the relevant binding parameters is available. Through refinement of this modeling approach more context-specific dosing of agonist/antagonists could be determined which may decrease side effects associated with the drug administration.

Topics: Antibodies, Monoclonal; Carcinoma, Small Cell; Cell Division; Dose-Response Relationship, Drug; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Models, Biological; Peptides

Various polypeptide hormones including vasopressin (VP) and gastrin-releasing peptide (GRP) are produced by small cell lung carcinomas (SCLC). VP as well as GRP have mitogenic effects on several cell types and are proposed to be autocrine growth factors. In this study the presence of VP mRNA, oxytocin (OT) mRNA and GRP mRNA was investigated in cell lines derived from SCLCs. Out of 26 cell lines 3 contained low amounts of VP mRNA (GLC-8, SCLC-21H and NCI-H345) and 7 contained abundant GRP mRNA (GLC-16, GLC-1-M13, SCLC-22H, NCI-H249, NCI-H345, NCI-H449 and NCI-H450). The GRP mRNA-containing cell lines belong to the classic SCLC type, whereas VP mRNA was found in two classic and one variant cell line. None of the SCLC cell lines contained detectable levels of OT mRNA. Of the three VP-expressing SCLC cell lines, GLC-8 had the highest level of VP mRNA. Both the length of the transcript and the hybridization with different probes containing exons A and C of the VP gene suggest that the detected transcript is a normal VP messenger. SCLC GLC-8 contained low levels of VP immunoreactivity and VP receptors. In GLC-8 an autocrine role of VP may be suspected.

Topics: Base Sequence; Blotting, Northern; Carcinoma, Small Cell; DNA Probes; Gastrin-Releasing Peptide; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Molecular Sequence Data; Oxytocin; Peptide Biosynthesis; Peptides; RNA, Messenger; RNA, Neoplasm; Tumor Cells, Cultured; Vasopressins

Serial changes in serum gastrin level were detected by radioimmunoassay in 58 lung cancer patients before and after operation. In comparing these tests with those of 40 cases of noncancerous thoracic lesions and 151 normal adults, the serum gastrin from lung cancer patients is significantly higher than that of noncancerous thoracic lesions and normal individuals (P less than 0.01). The gastrin level is closely related to stage of cancer, size of primary tumor, presence of lymph node metastasis, and type of histological classification. The serum gastrin was found to decrease gradually after the removal of the tumor and to return to normal on the 14th postoperative day. Those patients whose serum gastrin level can return to normal on the 14th postoperative day will have a good prognosis; if not, their prognosis will be very poor. These results suggest that serum from patients with lung cancer contains a high concentration of gastrin that can help differentiate benign from malignant thoracic lesions and evaluate prognosis of patients with lung cancer. Therefore, the cause of high serum gastrin in patients with lung cancer is likely due to the gastrin-producing property of the lung cancer cells.

Topics: Adenocarcinoma; Adult; Aged; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Female; Gastrin-Releasing Peptide; Gastrins; Humans; Lung Neoplasms; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Staging; Peptides; Postoperative Period; Prognosis; Thoracic Diseases

We investigated the interaction between human lung cancer cells, laminin, and several differentiating agents. When grown on laminin coated substrate eight out of 11 small cell lung cancer (SCLC) cell lines exhibited attachment to laminin and three had extensive outgrowth of long neurite-like processes. Of seven non-small cell lung cancer cell lines, selected for their in vitro anchorage-independent growth, attachment was observed in only three cell lines, and process formation was far less extensive than in SCLC cell lines. Among several differentiating agents, only dcAMP, which alone induced attachment and some process formation, increased laminin-mediated attachment and process formation of two SCLC cell lines, NCI-N417 a variant cell line, and NCI-H345, a classic cell line. The expression of several neuroendocrine and neuronal markers was investigated in these two SCLC cell lines. The expression of the light subunit of neurofilaments increased in NCI-N417 within 3 to 4 days of seeding, while NCI-H345 exhibited approximately 5 fold increase in expression of the GRP gene and a 3 fold increase expression of the beta-actin gene. The expression of a number of other neuroendocrine and neuronal markers did not change following growth on laminin. The doubling times remained unchanged independent of the presence of and attachment to laminin while topoisomerase II gene expression levels in NCI-N417 cells decreased approximately 5 fold when cells were growing on laminin.

Topics: Acetamides; Actins; Bucladesine; Carcinoma, Small Cell; Cell Adhesion; Cell Differentiation; Cell Division; Dimethyl Sulfoxide; Gastrin-Releasing Peptide; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Intermediate Filaments; Laminin; Lung Neoplasms; Peptides; Theophylline; Tumor Cells, Cultured

The concentrations of immunoreactive (IR) corticotropin-releasing hormone (CRH) in 218 neuroendocrine tumors were determined by CRH radioimmunoassay. The tumors examined were 86 pancreatic endocrine tumors (PET), 22 neuroblastic tumors (NBT), 26 carcinoid tumors (CA), 24 pheochromocytomas (PHEO), 40 small cell lung carcinomas (SCLC) and 20 medullary thyroid carcinomas (MTC). IR-CRH was detectable in 21 neuroendocrine tumors (10 PET, four NBT, three CA, two PHEO and two SCLC) at levels of 10-2,700 ng/g wet weight (9.6%). The 21 patients with these CRH-producing tumors showed no clinical symptoms suggestive of Cushing's syndrome. The levels of plasma IR-CRH extracted by immunoaffinity chromatography were < 7.5 pg/ml in five normal subjects and a patient with a neuroblastic tumor containing 55 ng/g wet weight IR-CRH, but in a patient with a thymic carcinoid tumor containing 1,000 ng/g wet weight IR-CRH, the plasma level was elevated to 180 pg/ml. This patient did not have Cushing's syndrome nor an elevated plasma adrenocorticotropic hormone (ACTH) level. The concentrations of nine peptides (growth hormone-releasing hormone, somatostatin, ACTH, calcitonin, gastrin-releasing peptide, glucagon, vasoactive intestinal peptide, neuropeptide tyrosine and pancreatic polypeptide) were determined in extracts of the 21 IR-CRH-producing tumors. Some of these peptides were frequently found to be produced concomitantly with CRH. The results indicate IR-CRH to be produced by various neuroendocrine tumors, but Cushing's syndrome, due to the CRH, to be very rare. The results also show that CRH-producing tumors produce multiple hormones.

Topics: Adenoma, Islet Cell; Adrenal Gland Neoplasms; Adrenocorticotropic Hormone; Bombesin; Calcitonin; Carcinoid Tumor; Carcinoma, Small Cell; Chromatography, Gel; Corticotropin-Releasing Hormone; Gastrin-Releasing Peptide; Gastrins; Humans; Hypothalamus; Lung Neoplasms; Neoplasms; Neuroblastoma; Pancreatic Neoplasms; Peptides; Pheochromocytoma; Somatostatin; Thyroid Neoplasms; Vasoactive Intestinal Peptide

Topics: Amino Acid Sequence; Animals; Biomarkers, Tumor; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Molecular Sequence Data; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Signal Transduction

We have evaluated an anti-autocrine growth factor monoclonal antibody for potential use in the treatment of patients with small-cell lung cancer. The monoclonal antibody, designated 2A11, binds to the C-terminal region of the autocrine growth factor gastrin-releasing peptide and neutralizes its growth-promoting effects in vitro and in vivo. Equilibrium-binding analysis demonstrated that the peptide binds to the antibody (dissociation constant = 1.5 x 10(-10) at least as avidly as it binds to the tumor peptide receptor. Pharmacokinetic studies in normal BALB/c mice demonstrated an initial clearance half-life (alpha t1/2) of 24.3 +/- 4 hours and a secondary clearance half-life (beta t1/2) of 1039.6 +/- 309 hours, and biodistribution studies revealed a distribution pattern which generally reflected blood flow. Single intravenous infusions of 2A11 (20 mg/20-25-kg dogs) into normal mongrel dogs with surgically created gastric fistulas antagonized the stimulatory effects of exogenously infused gastrin-releasing peptide or bombesin on plasma gastrin release and gastric acid secretion. Toxicology studies in normal dogs (with gastric fistulas) infused with 50 mg 2A11 intravenously three times a week for 4 weeks failed to reveal any adverse behavioral, clinical, or pathological effects. Four of six dogs developed an immune response to 2A11. Anti-idiotypic antibodies elicited in two cases did not mimic the functional effects of the peptide. We conclude that the concept of immunoblockade of an autocrine growth factor appears feasible in vivo.

Topics: Animals; Antibodies, Monoclonal; Bombesin; Carcinoma, Small Cell; Dogs; Gastric Acid; Gastrin-Releasing Peptide; Gastrins; Growth Substances; Lung Neoplasms; Mice; Mice, Inbred BALB C; Peptides; Tissue Distribution

Immunoreactivity related to the gastrin-releasing peptide (GRP) precursor was detected in four different human breast cancer cell lines. The amounts and the characteristics in extracts from different breast carcinoma cells were compared with cell extracts from small cell lung cancer (SCLC) cells. Two different radioimmunoassays were employed, directed against the amino acid sequence 14-27 of GRP (IR-GRP) or the 42-53 amino acid sequence at the C-terminal end of the GRP precursor (GRP precursor fragment). In extracts from T47D cells cultured under serum free conditions, IR-GRP coeluted with GRP(14-27) or GRP(18-27) in Sephadex G-50 chromatography. No immunoreactivity was detected in the fractions containing high molecular weight components. In a total of 41 human breast carcinoma biopsies from different postmenopausal patients, IR-GRP was detected by immunohistological staining in 39% of the samples. When the GRP(14-27) peptide was added exogenously to breast cancer and SCLC cell lines under serum-free culture conditions, (3H)-thymidine incorporation was stimulated by GRP(14-27) in the SCLC cell lines. Of the breast cancer cell lines only the T47D cell line responded with an increase in (3H)-thymidine incorporation comparable to the increase observed with SCLC cells. Recently, it has been reported that GRP-like receptors are present in some human breast cancer cell lines, including the T47D cell line studied here. The breast cancer cell line T47D therefore expresses the GRP peptide and the receptor for GRP. The identification of GRP-like receptors on T47D cells is in accordance with our present observation of a growth response to GRP(14-27) as evaluated by increased (3H)-thymidine incorporation.

Topics: Breast Neoplasms; Carcinoma, Small Cell; Cell Division; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptide Fragments; Peptides; Protein Precursors

Gastrin-releasing peptide (GRP; mammalian bombesin) is present in the neuroendocrine cells of human fetal lung and in small cell lung carcinomas (SCLCs), where it may act as a growth factor. Considering the potential importance of GRP as a tumor marker, we have conducted a retrospective immunohistochemical analysis of 176 lung tumors for markers of GRP gene expression, as well as several other markers of neuroendocrine cell differentiation: chromogranin A, neuron-specific enolase, and calcitonin. The majority of carcinoids contained mature GRP, in contrast to only a minority of SCLCs and large cell lung carcinomas (LCLCs). However, a majority of SCLCs and LCLCs contained proGRP immunoreactivity. In situ hybridization did not add any information beyond what was obtained using proGRP antisera. In spite of sharing these neuroendocrine cell markers, SCLCs are associated with a graver prognosis than LCLCs. No prognostic significance was associated with immunostaining for GRP or several other markers of neuroendocrine cell differentiation.

Topics: Adult; Aged; Biomarkers; Carcinoid Tumor; Carcinoma; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Gene Expression; Humans; Immunoenzyme Techniques; In Situ Hybridization; Lung Neoplasms; Male; Middle Aged; Peptides; Retrospective Studies; RNA, Messenger; RNA, Neoplasm; Survival Analysis

The ability to establish long-term cell lines of small-cell lung cancer (SCLC) has provided an in vitro model for the disease. We report on the characterization of 10 new human SCLC cell lines established from 34 cytopathologically positive specimens. Based on morphologic and biochemical characterization, growth properties, and expression of MYC and neuroendocrine properties, eight cell lines were categorized as "classic" and two cell lines as "variant". Cytogenetic examination revealed loss of all or part of 3p in all nine SCLC cell lines analyzed. The smallest deletion in common was found at 3p21-3p25. Restriction fragment length polymorphism (RFLP) analyses with probes for 3p were performed for correlation with karyotypic data and supported the cytogenetic findings. In 21 SCLC specimens (cell lines and tumor tissue) with normal DNA, used for comparison, we observed loss of heterozygosity at RAF1 (3p25) in ten of ten informative pairs by using two RFLPs from the RAF1 locus. In addition, loss of heterozygosity was noted in nine of 10 pairs examined with DNF15S2 (3p21) and four of four with D3S3 (3p14). Analysis of cell lines and tumor specimens that lacked paired normal tissue showed a homozygous pattern with the RAF1 probes in all 18 cases. Northern blots revealed significant expression of RAF1 in all cell lines tested. The transcript size was normal. The cytogenetic and RFLP data suggest that the RAF1 locus at 3p25 is involved in the chromosomal deletion of SCLC.

Topics: Blotting, Northern; Carcinoma, Small Cell; Chromogranin A; Chromogranins; Chromosome Deletion; Chromosomes, Human, Pair 3; DNA Mutational Analysis; DNA, Neoplasm; Gastrin-Releasing Peptide; Genes, myc; Heterozygote; Humans; Lung Neoplasms; Neoplasm Proteins; Peptides; Polymorphism, Restriction Fragment Length; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-myc; Proto-Oncogene Proteins c-raf; Proto-Oncogenes; Tumor Cells, Cultured

Relationships among cytological features, doubling time, S-phase percentage, expression of myc-family oncogenes, DNA ploidy and biochemical properties were studied in thirteen small cell lung cancer cell lines. Six cell lines that grew slowly (average doubling time 99 h) and had lower S-phase percentages (average 32%) showed inconspicuous nucleoli (average area of 1.5 microns 2), and the remaining seven cell lines that grew quickly (average doubling time 45 h) and had higher S-phase percentages (average 44%) showed large and prominent nucleoli (average area of 6.1 microns 2). DNA index value obtained from flow cytometric DNA histograms showed that all cell lines except for H-69 cell line displayed aneuploidy. Ribbon-like cell arrangements were observed in the 7 cell lines that grew quickly, and in 1 cell line that grew slowly. Biochemically, six slow-growing cell lines and four fast-growing cell lines showed high levels of aromatic L-amino acid decarboxylase activity, while in the remaining three fast-growing cell lines its level was low. A high level of c-myc or N-myc oncogene expression was observed in all 7 cell lines that grew quickly, but not in any of the 6 cell lines that grew slowly. It appears that small cell lung cancer cell lines that grow quickly can be expected to have large nucleoli and ribbon-like cell arrangements and to express high levels of myc-family oncogenes, and that nucleolar size is a good indicator for growth characteristics.

Topics: Animals; Carcinoma, Small Cell; Cell Cycle; Cell Division; Cell Nucleolus; Creatine Kinase; DNA, Neoplasm; Flow Cytometry; Gastrin-Releasing Peptide; Gene Expression; Humans; Lung Neoplasms; Mice; Mice, Nude; Oncogenes; Peptides; Phosphopyruvate Hydratase; Ploidies; Proto-Oncogene Proteins c-myc; RNA; S Phase; Tumor Cells, Cultured

Gastrin-releasing peptide (GRP), a mammalian bombesin-like peptide, has been shown to be an important autocrine growth factor for small cell lung cancer (SCLC). However, not all SCLC cell lines express the GRP gene or respond mitogenically to GRP stimulation, suggesting the existence of other autocrine pathways in this tumor. Neuromedin B (NMB), the mammalian counterpart of amphibian ranatensin, has been shown to be a mitogen for SCLC cell lines in vitro. To determine whether NMB is a potential autocrine growth factor for lung tumors, NMB gene expression, peptide synthesis, and secretion have been investigated in a panel of SCLC and non-SCLC (NSCLC) cell lines. Northern blot analysis and enzymatic amplification from mRNA by polymerase chain reaction showed that the NMB gene was expressed in all SCLC and NSCLC cell lines examined. In contrast, the GRP gene was expressed in four of six classic SCLC cell lines but not in variant SCLC or NSCLC cell lines. Immunoreactive NMB was detected by radioimmunoassay in the majority of classic SCLC, in one of three variant SCLC and in one of three NSCLC cell lines, and secreted NMB was detected in medium conditioned by a SCLC and a NSCLC cell line. The present study also demonstrated the presence of immunoreactive GRP in the absence of detectable GRP gene expression. The antiserum used in the GRP radioimmunoassay failed to cross-react with NMB but showed some cross-reactivity with amphibian phyllolitorin raising the possibility that certain SCLC cell lines may produce a phyllolitorin-like peptide.

Topics: Base Sequence; Blotting, Northern; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Gene Expression; Humans; Lung Neoplasms; Molecular Sequence Data; Neurokinin B; Peptide Biosynthesis; Polymerase Chain Reaction; RNA; Tumor Cells, Cultured

Expression of gastrin-releasing peptide (GRP), the mammalian homologue of the amphibian bombesin, has been investigated at gene and protein level in a series of 28 primary breast carcinomas, in 6 mammary cancer cell lines and in one transplantable rat mammary carcinoma. Moderate to strong expression of GRP mRNA was detected in 5 breast carcinomas by Northern blot analysis with a pre-pro-GRP probe; 4 other cases were weakly reactive. Two of these cases also gave a specific immunocytochemical reaction for GRP, controlled with absorption experiments. Correlation with NE differentiation [as shown by chromogranins (Cg) and/or NSE and/or Grimelius positivity] was low, since only one case of breast carcinoma co-expressed GRP and Cg mRNAs. Breast cancer cell lines and a rat carcinoma gave negative results. GRP production in breast cancer did not appear to bear prognostic implications, but longer follow-up periods are needed to confirm these data. As shown in small-cell lung cancer, GRP might be involved in autocrine growth control mechanisms of a group of breast carcinomas.

Topics: Animals; Antibodies; Bombesin; Breast Neoplasms; Carcinoma, Intraductal, Noninfiltrating; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Gene Expression; Humans; Immunohistochemistry; Mammary Neoplasms, Experimental; Nucleic Acid Hybridization; Peptides

Bombesin/gastrin releasing peptide (BN/GRP) functions as an autocrine growth factor in small cell lung cancer (SCLC). Previously, this autocrine growth cycle was disrupted by a monoclonal antibody which binds to the carboxyl terminal of BN and neutralizes the peptide so that it is unable to interact with the BN/GRP receptor. Here a series of BN analogues were synthesized which have a reduced peptide bond near the carboxyl terminal. The analogues inhibited specific binding of 125I-GRP to SCLC cell line NCI-H345 in a dose-dependent manner and the analogue [D-Nal6, Psi13,14, Phe14] BN6-14 was approximately 6-fold more potent than was (Psi13,14, Leu14)BN with a 50% inhibition concentration value of 5 nM. [DNal6, Psi13,14, Phe14]BN6-14 and [Psi13,14, Leu14]BN had no effect on the cytosolic Ca2+ levels but antagonized the increase in cytosolic Ca2+ caused by 10 nM BN. [Psi13,14, Leu14]BN (1 microM) inhibited the growth of SCLC in vitro using a clonogenic assay by approximately 70% Also, injection of [Psi13,14, Leu14]BN (10 micrograms, s.c.) inhibited the growth of SCLC xenografts in nude mice in vivo by approximately 50%. These data suggest that the autocrine growth cycle of BN/GRP in SCLC may also be disrupted by peptide antagonists which bind to the BN receptor.

Topics: Animals; Bombesin; Calcium; Carcinoma, Small Cell; Dose-Response Relationship, Drug; Female; Gastrin-Releasing Peptide; In Vitro Techniques; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Signal Transduction; Tumor Cells, Cultured; Tumor Stem Cell Assay

The tachykinin family of neuropeptides, including substance P and neurokinins A and B, induce a transient increase in intracellular free calcium concentration in human small cell lung carcinoma (SCLC) cells, as measured with a calcium indicator fura-2. The effects are dose dependent and even greater than that of bombesin at equimolar concentrations in these cells. The tachykinins, like bombesin, induce calcium mobilization mainly from intracellular store(s). None of the peptides, however, shows a stimulatory effect on DNA synthesis. In addition, exogenously applied bombesin does not stimulate DNA synthesis at any concentration tested. We also examined the effects of a recently reported bombesin antagonist [D-Arg1, D-Phe5, D-Trp7,9, Leu11]substance P in SCLC cells, and compared them to those in Swiss 3T3 fibroblasts in which the mitogenic effect of bombesin is well characterized. The antagonist at 10(-5) M completely abolishes the Ca2+-mobilizing effect of 10(-7) M bombesin in SCLC cells, and that of 10(-9) M but not 10(-7) M bombesin in Swiss 3T3 cells. The antagonist at this concentration effectively inhibits the mitogenic action of bombesin (10(-9) M) in Swiss 3T3 cells; however, much higher doses (approximately 10(-4) M) are needed to inhibit DNA synthesis in SCLC cells. Moreover, the antagonist inhibits DNA synthesis in bombesin/gastrin-releasing peptide-nonproducing cells with a similar dose dependency as in producing cells. These results indicate that bombesin/gastrin-releasing peptide and other calcium mobilizing peptides do not always act as a growth factor in SCLC cells, and that the bombesin antagonist could inhibit growth of SCLC cells through a mechanism other than bombesin antagonism.

Topics: Bombesin; Calcium; Carcinoma, Small Cell; Cell Division; DNA, Neoplasm; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides; Substance P; Tachykinins; Tumor Cells, Cultured

The production and postsecretory stability of gastrin-releasing peptide (GRP) and the C-terminal part of the GRP precursor were studied in small cell lung cancer cell lines using RIAs developed against these two parts of the precursor. In three otherwise different cell lines (NIC-H345, NIC-H69, and NIC-H510), similar chromatographic patterns of mainly GRP-(18-27) and some GRP-(14-27) along with large fragments of the C-terminal counterpart of the precursor were found to be stored in the cells. In tissue culture medium, gel filtration chromatography indicated that postsecretory limited proteolysis of the GRP precursor fragments occurred. The amount of accumulated immunoreactivity varied among the three cell lines and between the two parts of the precursor. In medium in which only low amounts of GRP immunoreactivity accumulated, the radiolabeled GRP was degraded rapidly. When incubated with plasma, GRP-(14-27) disappeared within a few hours, whereas the C-terminal precursor fragments were stable. It is concluded that the postsecretory stability of peptides excised from the GRP precursor in small cell lung cancer cells varies under tissue culture conditions, but epitopes in the C-terminal part of the precursor are more stable in plasma than the small GRP peptides and, thus, may serve as a better indicator than GRP itself for expression of the GRP precursor in cancer cells.

Topics: Amino Acid Sequence; Biomarkers, Tumor; Bombesin; Carcinoma, Small Cell; Cell Line; Chromatography, Gel; Chromatography, High Pressure Liquid; Chromosome Mapping; Gastrin-Releasing Peptide; Gene Expression; Humans; Immunoradiometric Assay; In Vitro Techniques; Lung Neoplasms; Molecular Sequence Data; Peptide Fragments; Peptides; Sequence Homology, Nucleic Acid; Substance P

In the search for novel antiproliferative agents for small cell lung cancer (SCLC), we found the neuropeptide antagonist [Arg6, D-Trp7,9,MePhe8]substance P(6-11) to be effective in vitro. In murine Swiss 3T3 cells [Arg6,D-Trp7,9,MePhe8]substance P(6-11) was identified as a potent inhibitor of vasopressin-stimulated DNA synthesis which also blocks [3H]vasopressin binding to specific cell-surface receptors. It was a less potent antagonist of gastrin-releasing peptide and bradykinin in these cells but did not block the effects of other mitogens. In SCLC cell lines, [Arg6,D-Trp7,9,MePhe8]substance P(6-11) inhibited colony-formation in soft agarose and growth in liquid culture in a dose-dependent manner. It also blocked receptor-mediated Ca2+ mobilization induced by vasopressin, bradykinin, cholecystokinin, galanin, gastrin-releasing peptide, and neurotensin. We suggest that broad-spectrum neuropeptide antagonists can block multiple autocrine and paracrine growth loops in SCLC and could be useful therapeutic agents.

Topics: Animals; Bradykinin; Calcium; Carcinoma, Small Cell; Cell Division; Cells, Cultured; DNA, Neoplasm; Drug Screening Assays, Antitumor; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Mice; Peptide Fragments; Peptides; Recombinant Proteins; Substance P; Tumor Cells, Cultured; Vasopressins

In 17 cases of resected small cell carcinoma of the lung, there were 4 cases of central type and 13 cases of peripheral type. Histologic subtypes were classified into oat cell carcinoma (OAT), intermediate cell type (INT), and small cell carcinoma with large cell component (SC/LC). SC/LC was divided according to the criteria of Radice et al. Immunohistochemically, gastrin-releasing peptide (GRP) and neuron specific enolase (NSE) were used as markers for neuroendocrine cells, and keratin and secretory component (SC) were used as markers for epithelial and gland epithelial cells, respectively. Histologically, 4 cases of the central type were divided into 3 cases of INT and one case of SC/LC. Thirteen cases of the peripheral type were divided into 3 cases of OAT, 6 cases of INT, and 4 cases of SC/LC. SC/LC was more frequently seen in the peripheral type than in the central type. Immunohistochemically, there was no difference in the frequency of positive staining for GRP and NSE between the central and peripheral types, but positive staining for keratin and SC were more frequent in the peripheral type than in the central type. Three cases who survived more than 3 years were histologically divided into two cases of INT and one case of SC/LC. Immunohistochemically, these 3 cases showed positive staining for GRP or NSE, but also showed positive staining for keratin or SC. Our results showed that some of the peripheral type small cell carcinoma of the lung had histologic and immunohistochemical features which were different from those of typical small cell carcinoma. Long survival time after resection in some of the peripheral cases might be due to these features.

Topics: Aged; Aged, 80 and over; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Immunohistochemistry; Keratins; Lung Neoplasms; Middle Aged; Peptides; Phosphopyruvate Hydratase; Prognosis; Secretory Component

Small cell lung cancer (SCLC) tumor progression can involve partial or complete conversion to a more treatment-resistant non-small cell (NSCLC) phenotype. In a cell culture model of this phenomenon, we have previously demonstrated that insertion of the viral Harvey ras gene (v-Ha-ras) into SCLC cell lines with amplification and overexpression of the c-myc gene induced many NSCLC phenotypic features. We now report that the v-Ha-ras gene can also induce morphologic, biochemical, and growth characteristics consistent with the NSCLC phenotype in an N-myc amplified SCLC cell line, NCI-H249. We show that v-Ha-ras has novel effects on these cells, abrogating an SCLC-specific growth requirement for gastrin-releasing peptide, and inducing mRNA expression of three NSCLC-associated growth factors and receptors, platelet-derived growth factor B chain, transforming growth factor-alpha (TGF-alpha), and epidermal growth factor receptor (EGF-R). TGF-alpha secretion and EGF-R also appear, consistent with the induction of an autocrine loop previously shown to be growth stimulatory for NSCLC in culture. These data suggest that N-myc and v-Ha-ras represent functional classes of genes that may complement each other in bringing about the phenotypic alterations seen during SCLC tumor progression, and suggest that such alterations might include the appearance of growth factors and receptors of potential importance for the growth of the tumor and its surrounding stroma.

Topics: Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Cell Division; Eflornithine; Epidermal Growth Factor; ErbB Receptors; Gastrin-Releasing Peptide; Gene Expression; Genes, ras; Lung Neoplasms; Peptides; Platelet-Derived Growth Factor; Transforming Growth Factors

Topics: Biomarkers, Tumor; Carcinoma, Small Cell; Chromatography, Affinity; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Neoplasm Recurrence, Local; Peptides; Radioimmunoassay; Specimen Handling

A sensitive radioimmunoassay (RIA) system for plasma gastrin-releasing peptide (GRP) was developed using immune-affinity chromatography for plasma extraction. Plasma neuron-specific enolase (NSE) levels were determined by use of RIA without extraction. Plasma GRP levels in 12 control subjects were (mean +/- SD) 1.2 +/- 0.26pg/ml. Plasma GRP levels were elevated at frequencies of 79% in untreated patients with small cell lung carcinoma (SCLC). The levels in 21 patients with non-SCLC were not elevated. In nine of 10 patients with complete response (CR) or partial response (PR), plasma GRP levels decreased significantly when the patients were judged to have achieved CR or PR. In four patients with progressive disease (PD), the levels were elevated after treatment when compared with levels before treatment. In six of 10 patients with CR or PR, plasma NSE levels decreased significantly at the judgment of CR or PR. In two of four patients with PD, the levels were elevated after treatment. Furthermore, changes in plasma GRP level showed more excellent correlation with the therapeutic response than changes in plasma NSE level in the clinical courses of two patients with CR and a patient with PD. These results suggest that the plasma GRP level could be a useful tumor marker in SCLC patients.

Topics: Biomarkers, Tumor; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides; Phosphopyruvate Hydratase; Radioimmunoassay

Levels of gastrin-releasing peptide (GRP) were determined by radioimmunoassay in human normal main and lobar bronchus and parenchymal lung tissue extracts. It was found that the level of GRP differed significantly between all 3 areas. The concentration of GRP was statistically higher in main bronchus (median 6.74 ng/g) compared to both lobar bronchus (median 4.79 ng/g) and parenchymal lung (median 1.73 ng/g), and also statistically higher in lobar bronchus compared to parenchymal lung. Chromatographically, GRP-immunoreactivity in both main and lobar bronchial extracts corresponded to GRP1-27 and GRP18-27, while in lung tissue only one major species was identified which corresponded in retention time to GRP18-27. No significant difference was detected when the levels of GRP in normal lobar bronchus and normal lung tissue were compared to the levels in lobar bronchus and lung taken from patients with lung carcinoma, at a site adjacent to the carcinoma. However, a significant difference was observed between the GRP content of normal main bronchus compared to main bronchus from patients with carcinoma. GRP was measured in 26/56 lung carcinomas examined. The levels ranged from 42,000 ng/g in a carcinoid tumour to 0.18 ng/g in a squamous-cell carcinoma, though only in 6 tumours were the levels outside the range determined for normal pulmonary tissue. Chromatography of selected tumour extracts of different histopathologies showed that there were differences in the GRP products present.

Topics: Adenocarcinoma; Adult; Aged; Carcinoid Tumor; Carcinoma; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Chromatography, High Pressure Liquid; Female; Gastrin-Releasing Peptide; Gastrointestinal Hormones; Humans; Lung; Lung Neoplasms; Male; Middle Aged; Peptides; Radioimmunoassay

Gastrin-releasing peptide (GRP) is now known to be a very common product of small cell lung carcinoma (SCLC). With the aim of investigating the possible role of this peptide as a tumor marker of SCLC, we have developed a sensitive radioimmunoassay system for plasma immunoreactive GRP using immune-affinity chromatography for plasma extraction. Plasma immunoreactive GRP levels in control subjects were determined by using 15 ml of plasma as the starting material (minimum concentration detectable, 0.8 pg/ml). The levels in 10 control subjects were (mean +/- SD) 1.2 +/- 0.27 pg/ml; range, 0.86-1.7 pg/ml. This assay system was applied for the clinical use by using 3 ml of plasma as the starting material (minimum concentration detectable, 4.0 pg/ml). Plasma immunoreactive GRP levels were elevated in SCLC patients at frequencies of 71% in patients with limited disease and 80% in those with extensive disease. Furthermore, a change in the level showed excellent correlation with the therapeutic response. In six patients with complete response who had had elevated levels before treatment, the levels decreased to an undetectable range when the tumor disappeared, and they remained undetectable until 1 month later, when the patients were judged to have achieved complete response. In the partial response group, plasma immunoreactive GRP levels had decreased to an undetectable level in two of three patients, when the patients achieved partial response. In four patients with progressive disease, plasma immunoreactive GRP levels were elevated at the time of the progressive disease judgment, when compared with levels before treatment. The levels in 21 patients with non-SCLC (10 with adenocarcinoma, seven with squamous cell carcinoma and four with large cell carcinoma) were not elevated. These results indicate the plasma immunoreactive GRP level as a useful tumor marker in SCLC patients. It is now believed that GRP can function as an autocrine growth factor for SCLC. The present study suggests that the possible autocrine growth factor could serve as a reliable tumor marker for cancer patients.

Topics: Adenocarcinoma; Biomarkers, Tumor; Carcinoma, Small Cell; Chromatography, Gel; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides

Products of the gastrin-releasing peptide gene were isolated from culture medium supernatant of a small cell lung cancer line, NCI-H345, by several (high performance liquid chromatography) HPLC steps. The column eluates were monitored by immunoassay and absorbance profiles. Gastrin-releasing peptide was identified in HPLC eluates by a specific radioimmunoassay. Two carboxyl-terminal gastrin-releasing peptide gene-associated peptides were identified by a radioimmunoassay specific for their predicted carboxyl terminus. The amino termini of these two peptides were determined by microsequence analysis. The shorter peptide was revealed to be a fragment of the larger peptide. Expression of an alternate mRNA was shown by isolation and characterization of a novel tetradecapeptide. Amino acid analysis, microsequence analysis, and mass spectral analysis confirmed that the structure was Ser-Leu-Leu-Gln-Val-Leu-Asn-Val-Lys-Glu-Gly-Thr-Pro-Ser. This peptide represents the carboxyl terminus of a peptide resulting from alternate processing of gastrin releasing peptide mRNA. This mRNA contains a 19-base deletion, creating a frame shift. A radioiodinated synthetic analog of this peptide (Tyr-Leu-Val-Asp-Ser-Leu-Leu-Gln-Val-Leu-Asn-Val-Lys-Glu-Gly-Thr-Pro-Ser ) bound specifically to a small cell cancer line with high affinity, suggesting possible biological activity of the isolated peptide.

Topics: Amino Acid Sequence; Carcinoma, Small Cell; Cell Line; Chromatography, High Pressure Liquid; Cloning, Molecular; DNA, Neoplasm; Gastrin-Releasing Peptide; Gastrointestinal Hormones; Genes; Humans; Lung Neoplasms; Molecular Sequence Data; Peptide Fragments; Peptides; Protein Sorting Signals; RNA, Messenger

The potency of 3 reduced peptide bond analogues of bombesin (BN) was investigated using small cell lung cancer (SCLC) cell lines. (Psi13,14, Leu14)BN, (Psi9,10, Leu14)BN and (Psi12,13, Leu14)BN inhibited specific binding of 125I-GRP with IC50 values of 15, 90, and 600 nM. (Psi13,14, Leu14)BN and (Psi9,10, Leu14)BN did not elevate cytosolic Ca2+ levels but antagonized the increase in cytosolic Ca2+ caused by BN. (Psi13,14, Leu14)BN antagonized the clonal growth of SCLC cells caused by BN. These data indicate that reduced peptide bond analogues may disrupt the autocrine growth cycle of SCLC cells by functioning as BN receptor antagonists.

Topics: Bombesin; Calcium; Carcinoma, Small Cell; Cell Division; Chemical Phenomena; Chemistry; Clone Cells; Gastrin-Releasing Peptide; Lung Neoplasms; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Tumor Cells, Cultured

Gastrin releasing peptide (GRP) is a 27-residue peptide hormone which is analogous to the amphibian peptide bombesin. GRP serves a variety of physiological functions and has been implicated as an autocrine factor in the growth regulation of small cell lung cancer cells. We have developed a series of potent GRP antagonists by modification of the COOH terminus of N-acetyl-GRP-20-27. The most potent member of this series, N-acetyl-GRP-20-26-OCH2CH3, exhibits an IC50 of 4 nM in a competitive binding inhibition assay. This compound blocks GRP-stimulated mitogenesis in Swiss 3T3 mouse fibroblasts, inhibits GRP-dependent release of gastrin in vitro, and blocks GRP-induced elevation of [Ca2+]i in H345 small cell lung cancer cells. These results demonstrate that while residues 20-27 of GRP influence binding of the parent peptide to its receptor, the COOH-terminal amino acid is primarily responsible for triggering the subsequent biological response.

Topics: Amino Acid Sequence; Animals; Binding, Competitive; Bombesin; Calcium; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Gastrins; Humans; Lung Neoplasms; Mice; Molecular Sequence Data; Oligopeptides; Peptides; Rats; Rats, Inbred Strains; Structure-Activity Relationship; Tumor Cells, Cultured

The effects of bombesin on three human small cell lung carcinoma cell (SCLC) lines (NCI-H69, NCI-H128, and NCI-H345) have been examined and compared to the effects of the peptide on the mouse fibroblast cell line Swiss 3T3, and the rat pituitary tumor cell line GH3W5. While all three SCLC lines expressed messenger RNA encoding pro-gastrin releasing peptide (GRP), only the NCI-H345 cells expressed detectable membrane receptors for GRP and responded to nanomolar concentrations of bombesin as shown by 125I-GRP binding, total inositol phosphate accumulation, and increased clonal growth in soft agarose. These data show that some SCLC lines are insensitive to bombesin and do not express detectable membrane receptors for GRP.

Topics: Animals; Blotting, Northern; Bombesin; Carcinoma, Small Cell; Cell Division; Cell Line; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Mice; Peptides; Phosphatidylinositols; Rats; Receptors, Bombesin; Receptors, Neurotransmitter; RNA, Messenger; Tumor Cells, Cultured

Topics: Biomarkers, Tumor; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides; Phosphopyruvate Hydratase

Pretreatment serum neuron specific enolase (NSE) and plasma bombesin/gastrin releasing peptide (BN/GRP) were measured in 92 lung cancer patients and 17 controls. The mean level of NSE (p less than 0.001) and BN/GRP (p less than 0.05) was significantly raised in patients with small cell lung cancer (SCLC, n = 62) compared to non-SCLC (n = 30) and controls. The mean concentration of NSE in extensive SCLC was significantly greater (p less than 0.005) than in limited stage but with a substantial overlap of values. Forty-seven out of 62 SCLC patients had at least one of the two markers raised (sensitivity 76%, specificity 83%), 44 had raised NSE (sensitivity 71%, specificity 89%) but only 24 had BN/GRP raised (sensitivity 42%, specificity 91%). At restaging, 16 of 19 patients with SCLC responsive to chemotherapy showed a significant fall of NSE; on the other hand, BN/GRP fell significantly in only 3 patients, remaining unchanged in the majority of responding patients. In conclusion, the combined determination of NSE and BN/GRP in SCLC, at diagnosis and during the follow-up, was not found to be superior to NSE determination alone.

Topics: Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Bombesin; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Middle Aged; Peptides; Phosphopyruvate Hydratase

Many small-cell lung cancers (SCLCs) produce gastrin-releasing peptides (GRPs) (mammalian bombesin) but the plasma concentration of GRP is rarely elevated, possibly because of its rapid elimination. We developed a radioimmunoassay for the C-terminal flanking peptide of proGRP and measured its concentration in plasma from 71 patients with SCLC, in 27 healthy subjects and in 49 patients with other diseases including lung carcinomas. In addition, we studied the molecular size of immunoreactive C-flanking peptide in two SCLC cell lines and in plasma from SCLC patients. The concentration of immunoreactive C-flanking peptide in normal subjects and in control patients did not exceed 10 pmol/L and 26 pmol/L, whereas 72% of the SCLC patients had C-flanking peptide concentrations above 10 pmol/L. In patients with extensive disease (n = 35) the median concentration was 71 pmol/L (range, 10 to 940). ProGRP C-flanking peptide levels paralleled the clinical course in 12 patients. The molecule(s) responsible for the immunoreactivity had a molecular size of about 8 to 10 kd in both patient plasma and tumor cell lines, suggesting that the measured peptide(s) represented major fragment(s) if not the entire C-flanking peptide of proGRP. Thus this peptide(s) seems to be a useful marker for SCLC.

Topics: Biomarkers, Tumor; Carcinoma, Small Cell; Chromatography, Gel; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Molecular Weight; Peptide Fragments; Peptides; Protein Precursors; Radioimmunoassay; Tumor Cells, Cultured

In the search for a more potent bombesin antagonist, we found [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P to be effective in mouse fibroblasts and to inhibit the growth of small cell lung cancer, a tumor that secretes bombesin-like peptides that may act as autocrine growth factors. In murine Swiss 3T3 cells, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P proved to be a bombesin antagonist as judged by the following criteria: (i) inhibition of DNA synthesis induced by gastrin-releasing peptide and other bombesin-like peptides; (ii) inhibition of 125I-labeled gastrin-releasing peptide binding to the bombesin/gastrin-releasing peptide receptor; (iii) reduction in cross-linking of the Mr 75,000-85,000 protein putatively a component of the bombesin/gastrin-releasing peptide receptor; (iv) blocking of early cellular events that precede mitogenesis--calcium mobilization and inhibition of epidermal growth factor binding. [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P was 5-fold more potent than the antagonist [D-Arg1,D-Pro2,D-Trp7,9,Leu11]substance P. [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P also inhibits mitogenesis induced by vasopressin but not that induced by a variety of other mitogens. Both antagonists reversibly inhibited the growth of small cell lung cancer in vitro in a concentration-dependent manner. Peptide antagonists could, therefore, have far-reaching therapeutic implications.

Topics: Amino Acid Sequence; Animals; Binding, Competitive; Bombesin; Carcinoma, Small Cell; DNA Replication; Epidermal Growth Factor; Gastrin-Releasing Peptide; Lung Neoplasms; Mice; Mitosis; Molecular Weight; Peptides; Substance P; Tumor Cells, Cultured

Small cell lung cancer (SCLC) produces several neuroendocrine peptides, including gastrin-releasing peptide (GRP), the mammalian equivalent of bombesin. There is some evidence to support the suggestion that GRP is an autocrine regulator of SCLC growth. Therefore, we have tested the effect of bombesin and two antagonists of bombesin on SCLC cell growth in a serum-free liquid tissue culture system. The antagonists used were analogues of substance P: spantide and (D-Arg1, D-Pro2, D-Trp7,9, Leu11) substance P. The cell lines used in this study all produced GRP-related peptides and one line had demonstrable GRP receptors. Exogenous bombesin did not cause any stimulation of growth in the liquid culture assay. The bombesin antagonists inhibited SCLC cell growth, but apparently not via the bombesin receptor. The bombesin used was biologically active because it stimulated the proliferation of Swiss 3T3 fibroblasts. The antagonists caused inhibition of this bombesin-induced proliferation, which was reversed by addition of excess bombesin. In addition, the antagonists and substance P alone stimulated proliferation of 3T3 cells, indicating that they may interact with another growth factor receptor on 3T3 cells. We conclude that growth of SCLC cells is not dependent on bombesin under all in vitro culture conditions because bombesin failed to stimulate growth in liquid cultures and the growth inhibition caused by bombesin antagonists was probably not mediated by the bombesin receptor.

Topics: Animals; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Lung Neoplasms; Mice; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Substance P; Tumor Cells, Cultured

Bombesin-like peptides are found in many different human tumors and are thought to function as an autocrine growth factor for small cell lung cancer in humans. In this study, a human small cell lung carcinoma (NCI-H69) was s.c. implanted bilaterally into the flanks of 12 nude mice. The mice were randomized and divided into two groups and given either bombesin (20 micrograms/kg) or saline i.p. 3 times a day. Tumor areas were measured twice weekly for 6 wk. At sacrifice, the tumors and normal pancreas were excised, weighed, and assayed for DNA, RNA, and protein content. Significant stimulation of tumor growth was observed at weeks 4, 5, and 6. Tumor weight at sacrifice was significantly elevated (77%) above the control, as was DNA content (78%). Bombesin significantly increased the weight (42%), DNA (48%), and protein (61%) contents of the normal mouse pancreas. We conclude that bombesin may act as an autocrine growth factor, or indirectly through the release of other growth factors, on human small cell lung carcinoma.

Topics: Animals; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Male; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Transplantation, Heterologous

BN/GRP-like peptides are produced in high concentrations in SCLC cell lines and in low concentrations in beta-lymphoblastoid cell lines. The BN/GRP-like peptides are secreted from SCLC cell line NCI-H345 by stimuli which elevate the intracellular cAMP levels. These stimuli include theophylline, PHI, secretin and VIP. Also, elevated plasma levels of BN/GRP-like peptides are found in patients with extensive SCLC. In these patients the levels of BN/GRP-like peptides can be increased further approximately 5-fold after secretin infusion. Because SCLC cells make and secrete BN/GRP-like peptides, they may function as regulatory peptides in this disease.

Topics: Carcinoma, Small Cell; Cell Line; Cyclic AMP; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Secretin

Creatine kinase (CK-BB), neuron specific enolase (NSE), ACTH, calcitonin, serotonin and gastrin releasing peptide (GRP) were measured in serum or plasma before and immediately after initiation of treatment in patients with small cell lung cancer (SCC). Pretherapeutic elevated concentrations of CK-BB were found in 82% of extensive disease patients and in 50% of patients with local disease. NSE was raised in 72% with extensive disease versus 14% of patients with local disease. Calcitonin and ACTH were raised in 27% and 28%, respectively, in all patients without significant difference between extensive and local disease patients. Serotonin was generally overall elevated in 10% and GRP in 7% but elevations were seen only in patients with extensive disease. Out of the four most frequently elevated substances at least one marker was elevated in 80% of all the patients, including 91% in extensive stage patients and 71% in limited stage patients. Frequent initial monitoring of the substances showed an increase in the concentrations of pretherapeutic elevated CK-BB and NSE on day 1 or 2 followed by a sharp decrease within 1 week. These changes were correlated to objective clinical response determined within 4-8 weeks. The results indicate that serum CK-BB and NSE are potential markers for SCC at the time of diagnosis and that changes in the concentrations during the first course of cytostatic therapy are promising as biochemical tests for early detection of response to chemotherapy.

Topics: Adrenocorticotropic Hormone; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Calcitonin; Carcinoma, Small Cell; Creatine Kinase; Gastrin-Releasing Peptide; Gastrointestinal Hormones; Humans; Lung Neoplasms; Peptides; Phosphopyruvate Hydratase; Serotonin; Time Factors

Mammalian gastrin-releasing peptide (GRP) is found in cells of neuroendocrine and neural origin, and GRP mediates a variety of physiological and trophic responses when it binds to high affinity cell surface receptors on effector cells. Analysis of cDNA clones derived from prepro-GRP mRNAs predict the concurrent expression of a unique series of peptide hormones, the GRP gene-associated peptides (GGAPs). Alternative RNA splicing of the primary GRP gene transcript results in mRNAs that could encode 3 distinct forms of GGAPs. Using specific antisera directed against synthetic peptides representing portions of the predicted GGAPs, we found multiple GGAP forms in the endocrine cells of human fetal lung and in human small cell lung cancer cells (SCLC). Within a single pulmonary endocrine cell, at least 2 of these 3 predicted forms could be demonstrated using immunohistochemical techniques. In addition, concordant expression of GRP and GGAPs was found in 10 SCLC cell lines and 3 human SCLC tumors. These findings establish GGAPs as a novel peptide family in man and warrant further investigation into their potential role in normal and malignant growth.

Topics: Amino Acid Sequence; Carcinoma, Small Cell; Cell Line; DNA; Fetus; Gastrin-Releasing Peptide; Gene Expression Regulation; Humans; Immunochemistry; Lung; Lung Neoplasms; Peptides; RNA, Messenger; Tumor Cells, Cultured

The gastrin-releasing peptide (GRP) is a neuropeptide hormone and growth factor produced normally by neural and neuroendocrine cells, as well as by human small-cell lung cancer (SCLC) tumors and derived cell lines. This study compares the structure of the human prepro-GRP gene in four SCLC cell lines that express variable levels of steady-state GRP mRNA. The regulation of GRP gene expression appears to be at the level of primary transcription based on nuclear run on studies. In the two SCLC cell lines expressing GRP we find a single transcription start site for GRP mRNA, and near this site we find four DNase I hypersensitive sites. These hypersensitive sites are absent in the two cell lines that do not express GRP. The presence of DNase hypersensitive sites in the promoter region of the GRP gene is the structural feature that best correlates with transcriptional activation. These four DNase hypersensitive sites are candidates for cis acting regulatory regions, which may be important in determining the level of transcription of the human prepro GRP gene.

Topics: Base Sequence; Carcinoma, Small Cell; Cell Line; Deoxyribonuclease I; DNA (Cytosine-5-)-Methyltransferases; Gastrin-Releasing Peptide; Gastrins; Gene Amplification; Gene Expression Regulation; Humans; Lung Neoplasms; Molecular Sequence Data; Nucleotide Mapping; Peptides; Promoter Regions, Genetic; Protein Precursors; RNA, Messenger; Transcription, Genetic

The human small cell lung carcinoma (SCLC) cell line NCI-H345 constitutively produces gastrin-releasing peptide (GRP), a peptide homologous to the mitogen bombesin. In addition, NCI-H345 cells express bombesin receptors and respond to bombesin with rapid activation of phospholipase C and mobilization of intracellular Ca2+. Treatment of NCI-H345 cells with a novel potent bombesin receptor antagonist [Leu13-psi-CH2NH-Leu14]bombesin blocked the increase in phosphatidylinositol turnover and cytoplasmic free Ca2+ ([Ca2+]i) stimulated by bombesin. Furthermore [Leu13-psi-CH2NH-Leu14]bombesin inhibited NCI-H345 colony formation in defined semisolid medium in the absence of exogenous GRP. The rapid, hormone-induced accumulation of inositol(1,4,5)trisphosphate was markedly more sensitive to antagonist inhibition than the hormone-induced Ca2+ transient, the sustained accumulation of inositol monophosphates, or colony formation in soft agarose. These data demonstrated inhibition of transmembrane signals associated with autocrine growth control in SCLC by a novel peptide receptor antagonist.

Topics: Bombesin; Calcium; Carcinoma, Small Cell; Cell Communication; Cell Line; Cytoplasm; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptide Biosynthesis; Receptors, Bombesin; Receptors, Neurotransmitter; Type C Phospholipases

High levels of BN/GRP are present in classic SCLC and lung carcinoids, whereas BN immunoreactivity is absent in variant SCLC, adenocarcinoma, large cell carcinoma, squamous cell carcinoma, and mesothelioma cell lines. BN-like peptides are secreted from classic SCLC into the tissue culture medium. The secretion rate of BN-like peptides from cell line NCI-H345 was increased 3-fold by VIP (1 microM). Also, VIP increased the cAMP levels in cell line NCI-H345 by an order of magnitude. Therefore, SCLC cells have functional VIP receptors which regulate the secretion of BN-like peptides. Also, SRIF (100 nM) inhibits the VIP-stimulated increase in cAMP levels and secretion rate of BN-like peptides from SCLC cells. Because BN stimulates colony formation, VIP and/or SRIF may be able to alter the growth of SCLC cells. BN-like peptides are secreted from SCLC cells into the plasma. The levels of BN immunoreactivity in the plasma of SCLC patients with extensive disease is 2- to 40-fold greater than that of patients with limited disease. Secretin infusion into patients with extensive disease produces a transient increase (7-fold) in the plasma concentration of BN-like peptides. BN-like peptides are also present in the CSF of SCLC patients. When released from SCLC cells, BN-like peptides may interact with cell surface receptors. [Tyr4]BN binds with high affinity (Kd = 0.5 nM) to a single class of sites (1500/cell) on cell line NCI-H345. The carboxyl terminus of BN or GRP is essential for high-affinity binding activity. BN-like peptides elevate cytosolic Ca2+ levels as a result of increased phosphatidylinositol turnover. The putative BN receptor antagonist [D-Arg1, D-Pro2, D-Trp7,9, Leu11]substance P inhibits high-affinity [Tyr4]BN binding, the ability of BN to elevate cytosolic Ca2+ levels, and colony formation of SCLC cells. Therefore, BN receptor antagonists may serve as useful agents to inhibit the growth of SCLC.

Topics: Bombesin; Carcinoma, Small Cell; Cell Line; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Secretin; Vasoactive Intestinal Peptide

The ability of bombesin-like peptides to elevate intracellular Ca2+ levels in small cell lung cancer cells was investigated using the fluorescent Ca2+ indicator Fura 2. Nanomolar concentrations of bombesin elevated cytosolic Ca2+ levels in the absence or presence of extracellular Ca2+. Potent bombesin receptor agonists, such as gastrin releasing peptide (GRP) or (GRP)14-27 elevated cytosolic Ca2+ levels whereas inactive compounds such as (D-Trp8)bombesin or (GRP)1-16 did not. Furthermore, the bombesin receptor antagonist (D-Arg1, D-Pro2, D-Trp7,9, Leu11) substance P (30 microM) had no effect on the Ca2+ levels by itself but antagonized the increase in Ca2+ caused by 10 nM or 100 nM bombesin. These data suggest that bombesin receptors may regulate the release of Ca2+ from intracellular organelles in small cell lung cancer cells.

Topics: Benzofurans; Bombesin; Calcium; Carcinoma, Small Cell; Cell Line; Cytosol; Fura-2; Gastrin-Releasing Peptide; Humans; In Vitro Techniques; Oligopeptides; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter; Somatostatin; Structure-Activity Relationship; Substance P; Vasoactive Intestinal Peptide

Topics: Carcinoma, Small Cell; Cell Count; Cell Line; DNA; Gastrin-Releasing Peptide; Gastrins; Gastrointestinal Hormones; Growth Substances; Humans; Lung Neoplasms; Mitosis; Molecular Weight; Peptides; Protein Biosynthesis; RNA; Time Factors

To examine the biochemical basis for growth factor-induced responses in human lung cancer cells, we used the quin2 technique to study the effect of the amphibian peptide bombesin and its congeners including mammalian gastrin-releasing peptide (GRP) on the intracellular free calcium level [Ca2+]i in small cell lung cancer cell lines. In five of eleven cell lines tested, Tyr4-bombesin or GRP elicited a rapid and transient increase in [Ca2+]i. The response was seen with as little as 1 nM ligand, was not affected by membrane depolarization, and derived in part from internal calcium stores. Desensitization to a second addition of active bombesin congeners occurs subsequent to initial addition of Tyr4-bombesin. Structure-activity analysis showed the carboxyl-terminal octapeptide was the active portion of the peptide. Analogs in which the carboxyl terminus was oxidized or deamidated were inactive. Ranatensin, litorin, alytesin, and GRP, but not physalaemin, were as active as Tyr4-bombesin. A monoclonal antibody to the carboxyl terminus of bombesin selectively blocked the increased [Ca2+]i elicited by Tyr4-bombesin. These studies suggest that bombesin congeners can act on some small cell lung cancer cell lines by a pathway utilizing increased [Ca2+]i.

Topics: Amino Acid Sequence; Bombesin; Calcium; Carcinoma, Small Cell; Cell Line; Dose-Response Relationship, Drug; Gastrin-Releasing Peptide; Humans; Kinetics; Lung Neoplasms; Oligopeptides; Peptides; Pyrrolidonecarboxylic Acid; Structure-Activity Relationship

A selected group of 263 pulmonary neuroendocrine tumours comprised 156 small cell carcinomas, five combined cell carcinomas, nine atypical carcinoid/small cell carcinomas, 32 atypical carcinoids, ten large cell/small cell carcinomas, and 51 carcinoid tumours. These were compared with a group of 109 non-small cell carcinomas, using four markers of neuroendocrine differentiation to determine differences in reactivity between the two groups and among the variants of neuroendocrine tumour. The antibodies used were neuron-specific enolase (NSE), protein gene product (PGP) 9.5, human bombesin, and the C-terminal flanking peptide of human bombesin (CTP). Most small cell carcinomas, carcinoid tumours, and atypical carcinoid variants showed immunoreactivity for both NSE and PGP 9.5 but a significant number of non-small cell carcinomas, mainly squamous cell carcinomas, were also positive (11 and 35 per cent, respectively). Bombesin was specific for neuroendocrine tumours, being demonstrable in 35 per cent carcinoids and 24 per cent small cell carcinomas, but staining was focal and often confined to scattered cells. Diffuse strongly positive immunoreactivity for CTP was seen in the majority of malignant neuroendocrine tumours, but only 12 per cent of carcinoid tumours were positive and non-small cell carcinomas were negative. CTP is therefore of potential value as a specific marker of malignant neuroendocrine tumours, particularly if the amount of biopsy material is limited and the tumour is an unusual variant, such as atypical carcinoid or large cell-small cell carcinoma.

Topics: Biomarkers, Tumor; Bombesin; Carcinoid Tumor; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Humans; Immunoenzyme Techniques; Lung Neoplasms; Neuropeptides; Peptide Fragments; Peptides; Phosphopyruvate Hydratase; Ubiquitin Thiolesterase

Gastrin-releasing peptide (GRP), the mammalian homolog of the amphibian peptide bombesin, is encoded in man by a single gene located on chromosome 18. Restriction enzyme and DNA sequence analyses establish that the gene is 10 kilobases in size with two introns of 4.8 and 3.9 kilobases. Exon 1 encodes the 5'-untranslated region, the signal peptide, and the first 23 amino acids of GRP. Exon 2 encodes the remaining three complete amino acids of GRP and the first 74 amino acids of the GRP carboxy-terminal extension peptide. Hence, intron 1 interrupts the coding region of the bioactive portion of GRP between the first and second nucleotides for Gly, the 24th amino acid of GRP. Exon 3 encodes the remainder of the GRP-extension peptide and the 3'-untranslated region. Two GC-rich, potential regulatory sequences and a sequence associated with regulation by cAMP lie between the CAAT and TATA boxes; the primary transcriptional start site is located 30 bases downstream from the TATA box. The second intron has an alternate donor site at its 5'-end and an alternate acceptor site at its 3'-end. S1 nuclease mapping demonstrates that differential RNA splicing using these sites results in the similar expression of three GRP mRNAs in GRP-containing neurons (in stomach and brain) as well as in GRP-containing neuroendocrine cells (fetal lung). In addition, the pattern of RNA splicing is similar between normal tissue and neoplastic tissue (small cell carcinoma of the lung and medullary carcinoma of the thyroid).

Topics: Base Sequence; Carcinoma; Carcinoma, Small Cell; DNA; Gastrin-Releasing Peptide; Genetic Code; Humans; Lung; Lung Neoplasms; Molecular Sequence Data; Neurons; Peptides; RNA Splicing; RNA, Messenger; Thyroid Neoplasms

Human gastrin-releasing peptide (GRP) mRNA was detected in the tumor tissues of medullary thyroid carcinomas and small cell lung carcinomas using synthetic oligodeoxyribonucleotides as hybridization probes. The amount of GRP mRNA was estimated by radiodensitometric hybridization assay. A good correlation was found between the amount of GRP mRNA and the concentration of immunoreactive GRP in the tumor tissues.

Topics: Carcinoma; Carcinoma, Small Cell; Densitometry; Gastrin-Releasing Peptide; Gastrins; Humans; Immunologic Techniques; Lung Neoplasms; Nucleic Acid Hybridization; Oligodeoxyribonucleotides; Peptides; Radioimmunoassay; RNA, Messenger; Thyroid Neoplasms

To demonstrate unbalanced distribution of subunits of human chorionic gonadotropin (hCG) in the lung and lung tumors and to clarify its significance in differentiation and carcinogenesis of the lung, immunohistochemistry was performed on human fetus, infant, and adult lungs, and endocrine and nonendocrine tumors of the lung. Tissues were immunostained for alpha-subunits and for beta-subunits of glycoprotein hormones (hCG, luteinizing hormone, follicle stimulating hormone, and thyroid stimulating hormone), serotonin, and gastrin-releasing peptide. Immunoreactive alpha-subunit was first identified in endocrine-like cells at the 39th gestational week, and was found in all infant lungs and two-thirds of adult lungs. The hCG beta-immunoreactive cells were extremely rare in an adult lung, and were not found in fetus or infant lungs. The alpha-subunit-containing cells were present in neuroepithelial bodies, tumorlets, carcinoid tumors, and small cell carcinomas of the lung (SCCL). There were occasionally alpha-subunit-containing cells in non-SCCL but one of the carcinomas also contained many serotonin-positive and gastrin-releasing peptide-positive cells in the same region. All alpha-subunit-immunoreactive cells lacked immunoreactivity for beta-subunits of glycoprotein hormones, except some for hCG beta in one carcinoid tumor. Immunoreactive cells for isolated hCG beta appeared much more frequently in non-SCCL than in SCCL. Most non-SCCL containing hCG beta-positive cells did not show alpha-subunit-immunoreactivity. Thus, immunohistochemical distribution of hCG-subunits was unbalanced and hCG-subunits may be expressed through an independent mechanism, commonly in the lung and lung tumors. The significance of isolated alpha-subunit is further discussed in light of multidirectional differentiation of lung neoplasms (14, 17).

Topics: Adult; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Chorionic Gonadotropin; Chorionic Gonadotropin, beta Subunit, Human; Fetus; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Infant, Newborn; Lung; Lung Neoplasms; Peptide Fragments; Peptides; Serotonin

Forty-seven surgically resected small cell lung carcinomas (SCLC) were immunohistochemically studied by using antibodies to various neuroendocrine and epithelial markers. SCLC was shown to be subdivided into two categories, with and without the immunoreactive neuroendocrine markers aromatic L-amino acid decarboxylase, gastrin-releasing peptide, serotonin, chromogranin A and neurofilament protein. Neuron-specific enolase (NSE) and creatine kinase BB isoenzyme (CK-BB), which are also considered to be neuroendocrine markers, had a tendency to be widely distributed in the SCLC with a neuroendocrine marker, but the immunoreactivity for both NSE and CK-BB varied in the SCLC without neuroendocrine markers. Therefore they were not included in the classification. Epithelial markers keratin, involucrin and epithelial membrane antigen were frequently observed in the SCLC with neuroendocrine markers, but less so in the SCLC without neuroendocrine markers. The data are discussed briefly in relation to "classic and variant" forms of SCLC in vitro and to a recently proposed histological classification of SCLC.

Topics: Aromatic-L-Amino-Acid Decarboxylases; Carcinoma, Small Cell; Creatine Kinase; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunochemistry; Isoenzymes; Keratins; Lung Neoplasms; Neurosecretory Systems; Peptides; Phosphopyruvate Hydratase; Protein Precursors

Bombesin/gastrin releasing peptide-like immunoreactivity (BLI) is found in the majority of small cell carcinoma of the lung (SCCL) cell lines examined. Because BLI is present in high concentration in SCCL we studied the mechanism of BLI secretion from several SCCL cell lines and in patients with SCCL. In cell line NCI-H345 the structurally related polypeptide hormones secretin, vasoactive intestinal peptide, and peptide histidine isoleucine as well as theophylline, a phosphodiesterase inhibitor, N6,O2'-dibutyryl cyclic adenosine 3':5'-monophosphate, a cyclic nucleotide analogue, increased BLI release by 16-120% and cyclic adenosine 3':5'-monophosphate by 36-350%. Similar results were obtained in SCCL cell line NCI-H209. i.v. injection of secretin (2 units/kg) significantly increased plasma BLI in 2 patients with extrapulmonary SCCL. These data suggest that SCCL cells possess receptors for secretin/vasoactive intestinal peptide and that receptor occupation stimulates in vitro and in vivo BLI secretion.

Topics: Alprostadil; Bombesin; Bucladesine; Carcinoma, Small Cell; Cyclic AMP; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Peptide PHI; Peptides; Secretin; Secretory Rate; Theophylline; Time Factors; Vasoactive Intestinal Peptide

cDNA clones to human prepro-gastrin-releasing peptide (prepro-GRP) mRNA detect synthesis of prepro-GRP-related transcripts in 4 of 7 small cell lung cancer (SCLC) cell lines and 1 of 2 metastatic SCLC tumors examined. A correlation is noted between prepro-GRP gene expression and the occurrence of bombesin-related immunoreactivity in SCLC cell lines. Examination of the structure of prepro-GRP transcripts found in SCLC reveals three types of prepro-GRP mRNA which differ in the structure of a putative GRP-associated peptide in the pro-GRP precursor. The subcellular distribution of prepro-GRP-related RNAs and structure of SCLC-derived prepro-GRP cDNA clones suggest that all three types of transcript could function as mRNAs, although there are differences in the prevalence of the different RNA types in different cellular compartments. Comparison of the sequence of cDNA clones with the sequence of a genomic prepro-GRP clone reveals that the three forms of prepro-GRP mRNA arise from a single primary transcript which undergoes alternative processing from two splice donor sites to two splice acceptor sites. The predicted amino acid sequence of the translated products of the three mRNAs are quite distinct, leading to predicted pro-GRP molecules of differing structure.

Topics: Amino Acid Sequence; Base Sequence; Carcinoma, Small Cell; Cloning, Molecular; DNA; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Neoplasm Proteins; Peptide Biosynthesis; Peptides; Protein Precursors; RNA Splicing; RNA, Messenger; RNA, Neoplasm

Topics: Bombesin; Bronchial Neoplasms; Carcinoid Tumor; Carcinoma, Small Cell; Chorionic Gonadotropin; Diagnosis, Differential; Female; Gastrin-Releasing Peptide; Gastrins; Humans; Immunoenzyme Techniques; Lung Neoplasms; Middle Aged; Peptides; Phosphopyruvate Hydratase

Fifty-three surgically resected small cell carcinomas of the lung were studied morphometrically, electron microscopically, immunohistochemically, and in terms of possible site of origin. Four subtypes of small cell carcinomas were identified: oat cell carcinoma (OAT), small cell carcinoma of the intermediate cell type (INT), combined oat cell carcinoma, and undifferentiated carcinoma of the small cell type (UCS). The latter type is presumed to be non-neuroendocrine. Morphometric analysis showed considerable overlap among OAT, INT, and UCS with respect to nuclear area, cell area, and nuclear/cytoplasmic ratio. Ultrastructurally, significantly more carcinomas categorized as OAT and INT contained neurosecretory granules than did those in the UCS category (P less than 0.01 and 0.05, respectively). Cells with tonofibrils were more frequent in UCSs than in OATs and INTs. Immunohistochemically, fewer UCSs than OATs contained cells with gastrin-releasing peptide, neuron-specific enolase, and Leu-7 (P = 0.5, P less than 0.05, and P less than 0.05, respectively). UCSs were located more frequently at the periphery of the lung than were OATs (P less than 0.01) and INTs (P = 0.06). These findings suggest that UCS may be a pathologic entity distinct from the typical neuroendocrine-type small cell carcinoma and that this subtype probably corresponds to small cell carcinoma with a "large cell component," and to very poorly differentiated adenocarcinoma and squamous cell carcinoma of the small cell type.

Topics: Carcinoma, Small Cell; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunochemistry; Lung Neoplasms; Microscopy, Electron; Peptides; Phosphopyruvate Hydratase

Tissues of 50 small cell lung carcinomas were examined for production of 17 peptide hormones. Only when the concentration of a peptide detected in the tumor was 10 pmol or more per g wet weight, was the peptide considered to be produced by the tumor. The frequency of production of at least one of these peptide hormones was 84%, and that of two or more hormones was 50%. These results indicate that peptide hormone production is a very common phenomenon in small cell lung carcinoma. Of the peptide hormones examined, gastrin-releasing peptide is produced with the highest frequency, suggesting that this peptide could play an important role in small cell lung carcinoma.

Topics: Adult; Amino Acid Sequence; Bombesin; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Hormones; Humans; Lung Neoplasms; Peptides; Radioimmunoassay

The binding of a radiolabeled bombesin analogue to human small cell lung cancer (SCLC) cell lines was investigated. (125I-Tyr4)bombesin bound with high affinity (Kd = 0.5 nM) to a single class of sites (2,000/cell) using SCLC line NCI-H446. Binding was reversible, saturable and specific. The pharmacology of binding was investigated using NCI-H466 and SCLC line NCI-H345. Bombesin and structurally related peptides, such as gastrin releasing peptide (GRP), but not other peptides, such as substance P or vasopressin, inhibited high affinity (125I-Tyr4)BN binding activity. Finally, the putative receptor, a 78,000 dalton polypeptide, was identified by purifying radiolabeled cell lysates on bombesin or GRP affinity resins and then displaying the bound polypeptides on sodium dodecylsulfate polyacrylamide gels. Because SCLC both produces bombesin/GRP-like peptides and contains high affinity receptors for these peptides, they may function as important autocrine regulatory factors for human SCLC.

Topics: Bombesin; Carcinoma, Small Cell; Cell Line; Chromatography, Affinity; Gastrin-Releasing Peptide; Humans; Kinetics; Lung Neoplasms; Peptides; Receptors, Bombesin; Receptors, Cell Surface; Substance P; Vasopressins

Twenty-seven cases of surgically resected large cell carcinoma of the lung including nine cases of giant cell carcinoma were examined ultrastructurally and immunohistochemically. Ultrastructurally, of 18 large cell carcinomas other than giant cell carcinoma eight showed characteristic differentiation toward adenocarcinoma, four toward adenosquamous carcinoma, and one each toward squamous cell carcinoma and neuroendocrine cell carcinoma, but the remaining four were undifferentiated. Six of the nine giant cell carcinomas also showed features of adenocarcinoma, two showed features of squamous cell carcinoma, and one was undifferentiated carcinoma. Immunohistochemically, secretory component (SC) was observed in seven of 14 cases with features of adenocarcinoma and two of four cases with features of adenosquamous carcinoma. Carcinomas with only squamous cell differentiation did not stain for SC. Keratin staining was positive in five of the 14 with features of adenocarcinoma, three of the four cases with features of adenosquamous carcinoma and two of the three cases with features of squamous cell carcinoma. The numbers of tumor cells positive for keratin and/or SC were small. One carcinoma with neurosecretory type granules was stained positively for calcitonin. These findings indicate that many large cell carcinomas showed differentiation toward glandular cells and/or squamous cells, and some did not show any differentiation ultrastructurally or immunohistochemically, indicating that the majority of large cell carcinomas are poorly differentiated form of either adenocarcinomas or squamous cell carcinomas.

Topics: Adenocarcinoma; Calcitonin; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Cytoplasmic Granules; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunoenzyme Techniques; Keratins; Lung Neoplasms; Peptides; Secretory Component; Staining and Labeling

A 60-year-old white woman with laryngeal oat cell carcinoma is described. She was a heavy smoker who had been treated seven years earlier with 5,000 rads for a well differentiated squamous cell carcinoma metastatic to a left submandibular lymph node. She presented this time with a two month history of hoarseness and tumor of the supraglottic larynx was found. There was clinical and chemical evidence of an ectopic ACTH syndrome. The histology and fine structure of the tumor were typical of oat cell carcinoma. Immunoreactive ACTH, GRP, NSE, Beta-endorphin, calcitonin, and keratin were found in the cytoplasm of the tumor cells by indirect immunoperoxidase techniques. We could find no previously reported case of laryngeal oat cell carcinoma with ectopic ACTH syndrome or cytoplasmic localization of polypeptides.

Topics: Adrenocorticotropic Hormone; Autopsy; Carcinoma, Small Cell; Female; Gastrin-Releasing Peptide; Gastrins; Hormones; Humans; Immunoenzyme Techniques; Keratins; Laryngeal Neoplasms; Middle Aged; Peptides; Phosphopyruvate Hydratase

Human small cell lung carcinoma (SCLC) cells have been shown to contain significant levels of a bombesin-immunoreactive peptide. The 27-amino acid peptide, gastrin releasing peptide (GRP), has recently been shown to be responsible for the bombesin-like immunoreactivity found in SCLC cells. Among four lung cancer cell lines examined in vitro, GRP exhibited mitogenic activity for two SCLC subtypes, but not for a squamous carcinoma or adenocarcinoma lung cell line. The mitogenicity of the GRP molecule has been isolated to the carboxyterminal fragment, designated GRP 14-27, which is in part homologous to bombesin. The aminoterminal fragment, GRP 1-16, is no homologous to bombesin and exhibits no mitogenic activity. Thus, GRP may be an important growth regulating or autocrine factor in human SCLC.

Topics: Carcinoma, Small Cell; Cell Count; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Microscopy, Electron; Mitogens; Peptides; Thymidine; Tritium

The role of regulatory peptides and the existence of specific peptide receptors are becoming established. However, techniques for the ultrastructural localisation of these receptors are fraught with difficulties. We propose here a novel technique for receptor localisation using a dimeric peptide ligand and electron microscopical immunocytochemistry. The dimeric ligand is used as a bridge between the receptor and a specific anti-ligand antibody. By this method we have localised receptors for bombesin in cells of small cell lung carcinoma in culture. The results support previous biochemical evidence for the existence of said receptors and the technique should be applicable for the localisation of other receptors recognising small ligands.

Topics: Bombesin; Carcinoma, Small Cell; Cell Line; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunochemistry; Ligands; Lung Neoplasms; Microscopy, Electron; Peptides; Receptors, Bombesin; Receptors, Cell Surface

Gastrin-releasing peptide (GRP) labeled with 125I at tyrosine-15 (125I-GRP) binds to intact quiescent Swiss 3T3 cells in a specific and saturable manner. Scatchard analysis indicates the presence of a single class of high-affinity binding sites of Kd = 0.5 X 10(-9) M and a value for the number of sites per cell of about 100,000. 125I-GRP binding was not inhibited by other mitogens for these cells, and cell lines that are mitogenically unresponsive to GRP do not exhibit specific GRP binding. Structure-activity relationships show a close parallel between the ability of a range of GRP-related peptides to both inhibit GRP binding and to stimulate mitogenesis. Further, GRP binding is selectively blocked in a competitive fashion by a novel bombesin antagonist, [D-Arg1, D-Pro2, D-Trp7,9, Leu11] substance P. In addition, this compound selectively inhibits GRP and bombesin-induced mitogenesis. These results demonstrate that the mitogenic response of Swiss 3T3 cells to peptides of the bombesin family is mediated by a class of receptors distinct from those of other mitogens for these cells.

Topics: Animals; Bombesin; Carcinoma, Small Cell; Cells, Cultured; DNA; Gastrin-Releasing Peptide; Iodine Radioisotopes; Lung Neoplasms; Mice; Peptides; Platelet-Derived Growth Factor; Receptors, Bombesin; Receptors, Cell Surface

Neuroendocrine tumours of the lung and gut are known to possess bombesin-like immunoreactivity. The recent observation that gastrin releasing peptide (GRP), a 27 amino acid peptide isolated from the porcine intestine, may be the mammalian analogue of bombesin led us to look for this peptide in a variety of human neoplasms. Formalin-fixed tissues from 85 tumours were examined by the immunoperoxidase technique, using specific antisera to the GRP molecule (1-27) and the GRP fragment (1-16). Intense cytoplasmic GRP immunoreactivity was seen in thyroid medullary carcinomas (3/3), carcinoids of lung, pancreas, and intestine (22/36), and paragangliomas (2/3). Less frequent staining was present in pulmonary small cell (oat cell) carcinomas (1/8) and pituitary adenomas (1/6). Complete absence of immunoreactivity was observed in three phaeochromocytomas, five Merkel cell tumours, six neuroblastomas and 15 non-neuroendocrine tumours. Normal neuroendocrine cells of the thyroid (C-cells) and bronchial mucosa (Kulchitsky cells) exhibited GRP immunoreactivity; nerve fibres from all sites failed to demonstrate staining for GRP. In each positive case, the pattern of staining for GRP (1-27) and GRP (1-16) was identical, although the GRP (1-16) immunostaining was weaker. These findings indicate that bombesin immunoreactivity in human neuroendocrine cells and tumours is attributable to GRP-like molecules and that GRP is a useful marker of neuroendocrine differentiation in many tumours.

Topics: Adenoma; Adrenal Gland Neoplasms; Amino Acid Sequence; Bombesin; Carcinoid Tumor; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Gastrins; Humans; Intestinal Neoplasms; Lung Neoplasms; Neoplasms; Neurosecretory Systems; Pancreatic Neoplasms; Peptides; Pheochromocytoma; Pituitary Neoplasms; Thyroid Neoplasms

Peptides corresponding closely in structure to the biologically active carboxyl terminal region of the amphibian peptide bombesin have now been isolated from several mammalian species, including man. Two principal forms have been found: one contains 27 amino acids and exhibits variations in amino acid sequence in the amino terminal region; the other is the carboxyl terminal decapeptide and probably does not vary among mammals. These peptides exhibit full immunoreactivity with most bombesin antisera and account for "bombesin-like immunoreactivity" that has been described in mammalian brain, sympathetic ganglia, and nerve fibers in the gut as well as in fetal lung endocrine cells and certain lung tumors, especially small cell lung carcinoma. The name gastrin releasing peptide (GRP) was given to the porcine and avian heptacosapeptides by McDonald and Mutt. The larger and smaller mammalian peptides now often are called GRP27 and GRP10. Both forms exhibit the full spectrum of activity shown by bombesin. Evidence has been obtained that neural release of mammalian bombesin-like peptides is physiologically important in regulation of gastrin release from the stomach. Lung tumors that produce bombesin-like peptides also have receptors for bombesin. These receptors appear to be involved in the autocrine regulation of tumor cell proliferation.

Topics: Animals; Bombesin; Carcinoma, Small Cell; Digestive System Physiological Phenomena; Gastrin-Releasing Peptide; Humans; Lung Neoplasms; Metabolic Clearance Rate; Nerve Tissue Proteins; Oligopeptides; Pancreas; Peptides; Receptors, Bombesin; Receptors, Cell Surface

Several reports have indicated that the amphibian peptide bombesin is present in oat-cell carcinoma of the human lung. The recent observation that gastrin-releasing peptide (GRP), a 27-amino acid peptide isolated from porcine intestine, may be the mammalian analog of bombesin led the authors to look for this peptide in human pulmonary tumors. Examination of 36 human lung tumors (8 carcinoids, 8 oat-cell carcinomas, and 20 non-oat-cell carcinomas) by immunohistochemistry and radioimmunoassay demonstrated the presence of high, although variable, levels of GRP in neuroendocrine tumors, and not in other histologic types. These findings indicate that bombesin immunoreactivity in human lung tumors should be attributed to GRP or GRP-like molecules and that GRP may be a useful marker of neuroendocrine differentiation.

Topics: Animals; Bombesin; Carcinoid Tumor; Carcinoma, Small Cell; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunoenzyme Techniques; Lung Neoplasms; Neurosecretory Systems; Peptides; Rabbits; Radioimmunoassay

Bronchial endocrine cells containing gastrin-releasing peptide (GRP), a mammalian analog of bombesin, and adrenocorticotropic hormone (ACTH) were immunohistochemically localized in paraffin sections of normal and pathologic human lungs. GRP-containing cells were present in fetal bronchi at the 12th gestational week and in "neuroepithelial bodies" about the time of delivery. In normal adult lungs, a few isolated GRP-containing cells were present in bronchial and bronchiolar mucosa. In bronchiectatic or fibrotic lungs, small clusters of GRP-containing cells were occasionally noted in basal bronchial mucosa. Pronounced GRP cell hyperplasia often was observed in ectatic bronchioles of lungs with tumorlet. Cells of pulmonary tumorlets mostly showed GRP immunoreactivity. Two bronchial carcinoids exhibited a moderate number of GRP-containing cells. Three of four small cell carcinomas, intermediate cell type could be designated "GRPomas" from the number of GRP-containing cells present. In four of 11 small cell carcinomas, oat cell type, GRP immunoreactivity was infrequently recognized. Immunoabsorption tests indicated that GRP immunoreactivity in lungs would mainly fall under the C-terminal fragment rather than the whole sequence of GRP. Bombesin immunoreactivity in human lungs should be attributed to GRP or GRP-like molecules, since no bombesin immunoreactants were identified with bombesin antiserum which shows no cross-reactivity to porcine GRP. ACTH-containing cells, also reactive to beta-endorphin antiserum, were absent from normal fetal or adult lungs but did accompany GRP-containing cells occasionally in ectatic non-neoplastic bronchioles, always in tumorlet cells, and often in endocrine lung tumors, although the cells containing GRP and ACTH were not identical. The significance of GRP in the physiology and pathophysiology of the lung is discussed, and the necessity of reevaluation of "ectopic" ACTH production in lung neoplasms is proposed.

Topics: Adrenocorticotropic Hormone; Adult; Antibodies; Bombesin; Bronchi; Carcinoid Tumor; Carcinoma, Small Cell; Fetus; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immune Sera; Immunochemistry; Immunoenzyme Techniques; Infant; Infant, Newborn; Lung; Lung Neoplasms; Peptides; Pulmonary Fibrosis; Substance P