gastrin-releasing-peptide and Carcinoma

Gastrin-releasing peptide (GRP), a bombesin-like peptide, is an autocrine or paracrine growth factor that can stimulate the growth of various cancer cells, making it an ideal target antigen to develop vaccines against cancer. In this study, we developed a novel DNA vaccine that encodes six tandem repeats of B-cell epitope GRP(18-27) (GRP6) flanked by HSP65 as carrier and four tandem repeats of mycobacterial HSP70(407-426) (M4) as helper T-cell epitopes for enhancement of immunogenicity. When intramuscularly immunized to mice, this anti-GRP DNA vaccine-induced GRP-specific antibody (Ab) responses that were at least 10-fold higher in magnitude compared with HSP65-GRP6 protein vaccine. Both prophylactic and therapeutic antitumor immunities induced by vaccination significantly suppressed the growth of GRP-dependent prostate carcinoma RM-1 in vivo and prolonged the survival of tumor-inoculated mice. Out results also showed that the immune sera with high titer of GRP-specific Abs effectively inhibited the growth of tumor in mice and dose dependently inhibited proliferation of cultured RM-1 cells in vitro, suggesting that the GRP neutralizing Ab is responsible for the protective and therapeutic antitumor activity of vaccination. These findings may be of great importance in the further exploration of the applications of growth factors identified in human in cancer therapy.

Topics: Animals; Cancer Vaccines; Carcinoma; Cell Line, Tumor; Cell Proliferation; Epitopes, B-Lymphocyte; Gastrin-Releasing Peptide; HSP70 Heat-Shock Proteins; Immunohistochemistry; Male; Mice; Prostatic Neoplasms; Recombinant Fusion Proteins; Vaccines, DNA

DNA vaccine represents an attractive approach for cancer treatment by inducing active immune-deprivation of gastrin-releasing peptide (GRP) from tumor cells, the growth of which is dependent on the stimulation of GRP. In this study, we developed a DNA vaccine using a plasmid vector to deliver the immunogen of six copies of the B cell epitope GRP(18-27) (GRP6). In order to increase the potency of this DNA vaccine, multiple strategies have been applied including DNA-prime protein-boost immunization and introduction of a foreign T-helper epitope into DNA vaccine. Mice vaccinated DNA vaccine boosting with HSP65-GRP6 protein induced high titer and relatively high avidity of anti-GRP antibodies as well as inhibition effect on the growth of murine prostate carcinoma, superior to the treatment using DNA alone or BCG priming HSP65-GRP6 protein boosting. Furthermore, the introduction of a novel foreign T-helper epitope into the GRP DNA vaccine showed a markedly stronger humoral immune response against GRP and tumor rejection even than the DNA-prime protein-boost strategy. No further stronger immunogenicity of this foreign T-helper epitope modified DNA vaccine was observed even using the strategy of modified DNA vaccine-priming and HSP65-GRP6 boosting method. The data presented demonstrate that improvement of potency of anti-GRP DNA vaccine with the above two feasible approaches should offer useful methods in the development of new DNA vaccine against growth factors for cancer immunotherapy.

Topics: Adjuvants, Immunologic; Animals; Antibody Affinity; Cancer Vaccines; Carcinoma; Cell Line; Epitopes, B-Lymphocyte; Epitopes, T-Lymphocyte; Gastrin-Releasing Peptide; Heat-Shock Proteins; Male; Mice; Mice, Inbred C57BL; Neoplasms, Experimental; Peptide Fragments; Prostatic Neoplasms; Recombinant Fusion Proteins; Vaccines, DNA; Vaccines, Synthetic

The mammalian gastrin-releasing peptide receptor (GRP-R) belongs to the superfamily of G protein-coupled receptors and mediates actions of the regulatory GRP and bombesin, the amphibian homolog of GRP. Owing to its frequent ectopic expression in some epithelial human malignancies, such as cancers of the colon, lung, and prostate, ligand-specific receptor activation may initiate intracellular signals of cell proliferation, differentiation and migration in this context. Because the underlying molecular mechanisms of aberrant human GRP-R (hGRP-R) expression in tumorigenesis remain unknown, we examined in this study the transcriptional activation of hGRP-R in gastrointestinal and prostate cancer cells, which natively express functional hGRP-R. Using various hGRP-R promoter mutants cloned into a luciferase reporter plasmid, transient transfection studies demonstrated robust transcriptional activation in gastrointestinal and prostate cancer cells. Although our study revealed distinct patterns of transcriptional hGRP-R activation in gastrointestinal and prostate cancer cells, genomic sequences between 97 and 247 bp upstream of the major RNA initiation site appear to be of particular significance for basal transcriptional hGRP-R activation. Based on this study, future examination of transcription factor interaction with the hGRP-R promoter will be important to identify molecular mechanisms of hGRP-R regulation relevant in human cancers that express functional receptor sites

Topics: Carcinoma; Cell Line, Tumor; Cell Transformation, Neoplastic; Epithelial Cells; Gastrin-Releasing Peptide; Gastrointestinal Neoplasms; Gene Expression Regulation, Neoplastic; Humans; Luciferases; Male; Mutation; Promoter Regions, Genetic; Prostatic Neoplasms; Receptors, Bombesin; RNA, Messenger; Transcriptional Activation

The growth of breast carcinoma is promoted by autocrine growth factors such as the bombesin (BN)-like peptides and epidermal growth factor (EGF). The stimulatory action of BN-like peptides can be blocked by the use of BN/gastrin-releasing peptide (GRP) antagonists.. The authors investigated the effects of synthetic BN/GRP antagonists RC-3095 and RC-3940-II on tumor growth and the expression of mRNA for EGF receptors and three BN receptor subtypes in MDA-MB-468 human breast carcinoma. Athymic nude mice with xenografts of MDA-MB-468 human breast carcinoma were injected subcutaneously for 6 weeks with RC-3940-II at doses of 20 or 40 microg/day. In another study, the effects of RC-3940-II and RC-3095 were compared.. RC-3940-II caused a significant and dose-dependent growth inhibition of MDA-MB-468 tumors in nude mice; therapy with either dose of RC-3940-II significantly (P<0.01) reduced the mean final tumor volume and weight compared with controls. RC-3940-II induced a persistent regression of > 50% of all tumors. One of 3 tumors treated with 20 microg of RC-3940-II and 3 of 5 tumors treated with 40 microg were found to have regressed completely by the end of the study. When RC-3940-II and RC-3095 were compared at the dose of 20 microg/day, both powerfully suppressed growth of MDA-MB-468 tumors, with RC-3940-II causing a complete regression of 2 tumors and RC-3095 a complete regression of 1 tumor. Receptor analyses of untreated MDA-MB-468 tumors revealed an overexpression of EGF receptors and two classes of binding sites for BN/GRP. mRNAs for receptors of GRP, neuromedin B, and BN receptor subtype-3 were detected by reverse transcriptase-polymerase chain reaction.. A virtual arrest of growth or regression of MDA-MB-468 human breast carcinoma after therapy with RC-3940-II and RC-3095 indicates that these BN/GRP antagonists could provide a new treatment modality for breast tumors expressing BN and EGF receptors.

Topics: Animals; Antineoplastic Agents; Bombesin; Breast Neoplasms; Carcinoma; Dose-Response Relationship, Drug; ErbB Receptors; Female; Gastrin-Releasing Peptide; Gene Expression Regulation, Neoplastic; Humans; Injections, Subcutaneous; Mice; Mice, Nude; Neoplasm Transplantation; Neurokinin B; Peptide Fragments; Polymerase Chain Reaction; Receptors, Bombesin; Remission Induction; RNA, Messenger; Transplantation, Heterologous; Tumor Cells, Cultured

Characterization of bombesin binding sites in healthy human lung was performed through direct binding techniques. There was limited binding in the absence of trypsin and chymotrypsin inhibitors, suggesting important activities of both enzymes in human lung and/or increased sensitivity of the bombesin sites toward them. In human lung membranes, bombesin, gastrin releasing peptide (GRP) and GRP-preferring bombesin receptor antagonists displaced [125I-Tyr4]bombesin binding with high affinities (36-177 nM), whereas neuromedin B possessed a lower affinity of 2878 nM. [D-F5Phe6,D-Ala11]bombesin-(6-13)-methyl ester, the most active GRP-preferring bombesin antagonist as yet reported, had the highest affinity among all antagonists tested whereas neuromedin B had the lowest affinity. These data demonstrate that the bombesin binding sites in the human lung are of the GRP-preferring type.

Topics: Binding Sites; Binding, Competitive; Bombesin; Carcinoma; Gastrin-Releasing Peptide; Humans; Lung; Lung Neoplasms; Neurokinin B; Peptide Fragments; Peptides

This report describes an immunohistopathologic analysis characterizing the incidence, pattern of distribution, and hormonal content of neuroendocrine (NE) cells in human benign prostate and prostatic adenocarcinoma.. Formaldehyde-fixed, paraffin-embedded material from 15 benign prostates, 31 primary prostatic adenocarcinomas, 16 metastatic lesions, 21 primary tumors treated with short-course diethylstilbestrol (DES), and 10 specimens from hormone-refractory patients were examined. NE cells were identified using silver histochemistry and a panel of immunohistochemical NE markers (chromogranin-A, serotonin, neuron-specific enolase), and specific peptide hormone antibodies.. NE cells were identified in all benign prostates. NE cells were identified in 77% of primary untreated adenocarcinomas with no significant differences with respect to pathologic stage. NE cells were found isolated and dispersed in the tumor, composing the minority of malignant cells. Double-labeling and serial section immunohistochemistry demonstrated the coexpression of prostate-specific antigen (PSA) in NE cells. In addition to serotonin, some tumors expressed multiple hormone immunoreactivities. NE cells were identified in 56% of metastatic deposits, with a similar pattern of distribution. In DES-treated cases, NE cells were found consistently in the adjacent benign epithelium, whereas 52% of tumors contained NE cells. Hormone-refractory tumors contained NE cells in 60% of cases.. This analysis demonstrates that a significant proportion of primary and metastatic prostatic adenocarcinomas contain a subpopulation of NE cells, the expression of which does not appear to be suppressed with androgen ablation and does not correlate with pathologic stage. Furthermore, NE cells coexpress PSA, suggesting a common precursor cell of origin. The elaboration of biogenic amines and neuropeptides suggests that NE cells dispersed in prostatic carcinoma may play a paracrine growth-regulatory role.

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Basement Membrane; Calcitonin; Carcinoma; Cell Differentiation; Chromogranin A; Chromogranins; Cytoplasm; Diethylstilbestrol; Gastrin-Releasing Peptide; Gastrins; Humans; Keratins; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Staging; Neurosecretory Systems; Peptides; Prostate; Prostate-Specific Antigen; Prostatic Neoplasms; Seminal Vesicles; Serotonin; Staining and Labeling; Thyrotropin

Female Syrian golden hamsters with N-nitroso-bis (2-oxopropyl) amine (BOP)-induced pancreatic cancers were treated for 2 months with bombesin/gastrin-releasing peptide (GRP) antagonist D-Tpi6,Leu13 psi(CH2NH)Leu14 bombesin(6-14) (RC-3095). Bombesin and GRP(14-27) were also administered alone and in combination with the antagonist RC-3095. RC-3095 exerted a dose-dependent inhibitory effect on growth of pancreatic cancers. The number of animals with pancreatic cancers was significantly lower in the group treated with 60 micrograms/day of RC-3095 and the weight of tumorous pancreata was reduced. Administration of bombesin or GRP alone did not stimulate the growth of pancreatic tumors and, in fact, had a slightly suppressive effect on cancers which was significant only in Experiment I. Bombesin and GRP (14-27) given together with RC-3095 did not nullify the inhibitory effect of the antagonist on pancreatic cancer growth. Actually, a greater inhibition of pancreatic tumors was observed after administration of RC-3095 together with bombesin or GRP, than with RC-3095 alone. The mechanism of action of bombesin, GRP, and bombesin antagonists on pancreatic cancers appears to be complex. The inhibitory effect of bombesin antagonists on pancreatic cancer growth was accompanied by a decrease in the binding capacity of EGF receptors in tumor membranes. Administration of bombesin also caused a down-regulation of EGF receptors and the greatest decrease in binding capacity of EGF receptors was observed after treatment with RC-3095 in combination with GRP. Inhibition of pancreatic cancer can thus be tentatively explained by some common pathways in the action of bombesin, GRP and their antagonists, that could be mediated by interference with EGF-receptor mechanisms.

Topics: Animals; Body Weight; Bombesin; Carcinoma; Cricetinae; Dose-Response Relationship, Drug; Down-Regulation; Epidermal Growth Factor; ErbB Receptors; Female; Gastrin-Releasing Peptide; Gastrins; Growth Hormone; Insulin-Like Growth Factor I; Mesocricetus; Nitrosamines; Pancreatic Neoplasms; Peptide Fragments; Peptides; Receptors, Bombesin; Receptors, Neurotransmitter

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

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

Determination of the Primary structures of peptides isolated from a human medullary thyroid carcinoma has provided insight into the pathways of post-translational processing of prohormones in the tumour cells. Cleavage of the signal peptide in preprocalcitonin occurs at the Ala25-Ala26 bond. The prohormone is further processed at the site of multiple basic residues to generate procalcitonin-(1-57)-peptide, procalcitonin-(60-91)-peptide (calcitonin), procalcitonin(60-116)-peptide (a C-terminally extended form of calcitonin) and procalcitonin-(96-116)-peptide (Katacalcin). CGRP-I but not CGRP-II, was isolated from the tumour together with a high-Mr form that may represent the unprocessed prohormone. Progastrin-releasing peptide was processed to a mixture of GRP-(1-27)-peptide and GRP-(18-27)-peptide, the latter component arising from proteolytic cleavage at the site of a single arginyl residue.

Topics: Calcitonin; Calcitonin Gene-Related Peptide; Carcinoma; Chromatography, High Pressure Liquid; Gastrin-Releasing Peptide; Gene Expression; Humans; Neurotransmitter Agents; Peptides; Protein Biosynthesis; Protein Precursors; Radioimmunoassay; Thyroid Neoplasms; Vasodilator Agents

Peptides synthesized by a human medullary thyroid carcinoma were purified to homogeneity by reverse-phase high performance liquid chromatography and structurally characterized by determination of amino acid composition, amino acid sequence, and fast atom bombardment mass spectra. The katacalcin-related material in the tumor extract was heterogeneous. Katacalcin (1-21) represented the predominant molecular form but metabolites, identified as katacalcin (1-20), (1-19), (1-15) and (1-13), were also identified in high concentration. Calcitonin gene-related peptide-I was isolated from the tumor but calcitonin gene-related peptide-II was absent. A minor component of calcitonin gene-related peptide-like immunoreactivity was of higher molecular weight and may represent an incompletely processed form of the prohormone. Gastrin-releasing peptide (1-27) and gastrin-releasing peptide (18-27) (neuromedin C) were isolated from the tumor but gastrin-releasing peptide (14-27) and bombesin were absent.

Topics: Adult; Amino Acid Sequence; Amino Acids; Calcitonin; Calcitonin Gene-Related Peptide; Carcinoma; Gastrin-Releasing Peptide; Humans; Male; Neuropeptides; Peptide Fragments; Peptides; Thyroid Neoplasms

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

Five peptide hormones including calcitonin (CT) and gastrin-releasing peptide (GRP), serotonin (5HT), CEA, nervous tissue specific proteins and monoclonal antibody Leu-7 were immuno-histochemically studied on 60 cases of medullary thyroid carcinoma (MTC). In addition, localization of varied products in the tumor cells and its relations with the clinical features in some cases were evaluated. MTC contains a variety of products in many cases, and CT and CEA were positive in all cases. In 50 of the 57 cases (87.7%), GRP was positive, which suggested that GRP could be a novel tumor marker for this tumor. Furthermore, in tumor cells and C-cell hyperplastic foci, identical cells were sometimes revealed to possess both CT and GRP. Existence of somatostatin (SS), substance-P (SP), beta-MSH, 5 HT, Leu-7 and NSE in the tumor cells were confirmed. NSE was positive in 32 of the 47 cases (61.8%) which could confirm that MTC possesses neuroendocrine nature. In two cases of autopsy in which the tumors were highly malignant in clinical course and undifferentiated in histology, most tumor cells showed poor stainability for peptide hormones, suggesting that specific qualities as neuroendocrine tumor had been lost. In familial cases, the tumor tended to contain multiple substances.

Topics: Adult; Aged; Calcitonin; Carcinoma; Female; Gastrin-Releasing Peptide; Hormones; Humans; Immunoenzyme Techniques; Male; Middle Aged; Peptides; Prognosis; Somatostatin; 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

Gastrin-releasing peptide, the mammalian counterpart of amphibian bombesin, has been found to be present in high concentration by radioimmunoassay in eight histologically confirmed medullary thyroid carcinomas and to be undetectable in postmortem normal thyroid tissue. Chromatographic analysis of the tumor extracts by gel permeation revealed two major peaks of gastrin-releasing peptide-like immunoreactivity (GRP-LI). However, reverse-phase high-pressure liquid chromatography demonstrated three immunoreactive peaks of GRP-LI. None of these immunoreactive peaks was coeluted with synthetic porcine GRP or amphibian bombesin, but one of the peaks exactly emerged in the position of neuromedin C (C-terminal decapeptide of GRP). Sections from nine primary or secondary tumours were immunostained for GRP using a peroxidase/anti-peroxidase technic. All the medullary thyroid carcinomas were shown to contain GRP-LI, specifically localized to the tumor cells. This immunoreactivity is elevated in plasma from some patients with this malignancy, raising the possibility that it may be used as an additional tumor marker.

Topics: Carcinoma; Chromatography, Gel; Chromatography, High Pressure Liquid; Gastrin-Releasing Peptide; Gastrins; Humans; Immunochemistry; Peptides; Radioimmunoassay; Thyroid Gland; Thyroid Neoplasms

Two cases of gastrin releasing peptide (GRP)-producing medullary thyroid carcinoma are presented. Immunohistochemical examination revealed the presence of GRP-like immunoreactivity (IR-GRP) in the primary tumor tissues. High concentration of IR-GRP was also demonstrated in extracts of the primary tumors by radioimmunologic means with use of a GRP-specific antiserum. Chromatographic analysis showed that the immunoreactivity was composed of at least two molecular forms: one behaved as synthetic porcine GRP on Sephadex G-50 gel filtration and the other as porcine GRP (14-27), a C-terminal active fragment of GRP. The IR-GRP was shown not to be attributed to bombesin-like immunoreactivity. Substance P-like immunoreactivity was not detected in the tumor tissues by either immunohistochemical or radioimmunologic means. This is, as far as the authors are aware, the first finding of IR-GRP as an ectopic product in medullary carcinoma.

Topics: Calcitonin; Carcinoma; Chromatography, Gel; Female; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunologic Techniques; Middle Aged; Peptides; Radioimmunoassay; Thyroid Neoplasms; Tissue Extracts

Immunoreactive gastrin-releasing peptide (IR-GRP) was found to be present in medullary carcinoma of the thyroid (MCT) by use of a radioimmunoassay (RIA) specific for the carboxyl-terminal portion of GRP. Immunohistochemical studies revealed IR-GRP in the MCT tumor cells, indicating that the tumor cells produce IR-GRP. Immunoreactive GRP was also detected in macroscopically normal thyroid tissue of patients with multiple endocrine neoplasia type II (MEN II, or Sipple's syndrome) and in areas of C cell hyperplasia and micronodules in the thyroids of patients with MCT. When these tissue extracts were examined with a bombesin RIA that recognizes bombesin but not GRP, no IR-bombesin was detected, suggesting that the IR-GRP detected in these tissues is more similar to GRP than to bombesin. IR-GRP was also undetectable in normal thyroid tissues. Plasma IR-GRP was also undetectable in normal thyroid tissues. Plasma IR-GRP was elevated to 130 to 780 pg/mL (normal: undetectable, less than 62.5 pg/mL) in three patients with metastatic MCT, and both calcium and tetragastrin increased the plasma levels of IR-GRP. Sephadex G-50 gel filtration of the MCT extracts revealed two peaks, one coeluted with porcine GRP (1-27) and the other eluted just after its carboxyl-terminal (14-27) fragment. There was a significant correlation (P less than 0.01) between the concentration of IR-GRP and that of IR-calcitonin in MCT tumor tissue and in macroscopically normal portions of thyroid tissue from two patients with MEN II, although the concentration of IR-GRP was only about 0.1% of that of IR-calcitonin.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Bombesin; Calcitonin; Carcinoma; Chromatography, Gel; Gastrin-Releasing Peptide; Humans; Peptides; Radioimmunoassay; Tetragastrin; Thyroid Neoplasms

Forty medullary carcinomas of the thyroid (MCT) with documented calcitonin (CT) production were studied immunohistochemically for the production of gastrin releasing peptide (GRP), a mammalian counterpart of amphibian bombesin. GRP-positive cells, revealed by an unlabelled peroxidase-antiperoxidase immunoenzyme histochemistry were found in 81% (34/40) of the MCTs. Variable numbers of tumor cells in positive MCTs were immunostained for GRP. In 3 cases with Sipple's syndrome, cells in scattered microscopic MCT nodules and hyperplastic intrafollicular C cells of the thyroid were frequently positive for GRP as well as for CT. Non-neoplastic C cells (or CT-positive cells) of the human thyroids were also positive for GRP. In the neoplastic and non-neoplastic C cell system, some cells were confirmed to be immunoreactive with both anti-GRP and anti-CT. All these findings indicate that GRP and CT are closely associated peptide hormones produced by the C cell system.

Topics: Calcitonin; Carcinoma; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunoenzyme Techniques; Peptides; Thyroid Gland; Thyroid Neoplasms