gastrins and Prostatic-Neoplasms

The aim of this review is to explore the clinical application of different PET radiopharmaceuticals in prostate cancer (PCa), beyond inhibitors of the prostate-specific membrane antigen (PSMA).. Choline PET represented in the last decades the standard of reference for PET imaging in PCa and has been recently included in clinical trials evaluating the efficacy of metastasis-directed therapy in oligo-metastatic disease. Fluciclovine, as synthetic amino acid, has been proposed for investigating PCa. The results obtained by the first prospective studies led to FDA approval in 2016 in patients with biochemical recurrence. Recently, phase II/III trials explored its accuracy compared with PSMA PET and its impact on patient management. Imaging the gastrin-releasing polypeptide receptor (GRPR) recently drawn attention. Radio-labelled GRPR antagonists have the potential to be used as theranostic agents. Further evaluation is needed to understand the relation between GRPR expression and hormonal-resistant PCa, and for tumors characterized by heterogeneity of receptors expressed (e.g. PSMA-negative) on their cell surface.. Other new generation PET tracers may play an important role in PCa, namely in case of PSMA-negative phenotypes.

Topics: Amino Acids; Antigens, Surface; Bombesin; Choline; Gastrins; Humans; Male; Positron Emission Tomography Computed Tomography; Prostatic Neoplasms; Radiopharmaceuticals

Bombesin (BBN)-conjugated polymeric nanoparticles to target docetaxel (DTX) to prostate cancer cells that overexpress gastrin-releasing peptides receptors.. In vitro cytotoxicity, uptake of nanoparticles and inhibition of cell migration were assessed against human prostate cancer cells. Preclinical pharmacokinetic and tissue-distribution studies of nanoparticles were performed in Balb/c mice and results compared with the marketed formulation Taxotere(®).. BBN-conjugated DTX-loaded nanoparticles exhibited higher cytotoxicity, inhibition of cell migration and colony formation than non-targeted nanoparticles or DTX alone. More BBN-conjugated nanoparticles were taken up at a faster rate than unconjugated nanoparticles. In vivo, this drug delivery improved pharmacokinetics of DTX by increasing mean residence time and decreasing clearance.. This study provides an alternate approach for polysorbate-free delivery of DTX, with improved in vivo performance.

Topics: Androgens; Animals; Antineoplastic Agents; Bombesin; Cell Line, Tumor; Docetaxel; Drug Delivery Systems; Gastrins; Humans; Male; Mice, Inbred BALB C; Nanoparticles; Prostate; Prostatic Neoplasms; Taxoids

The means of identifying prostate carcinoma and its metastases are limited. The contrast agents used in magnetic resonance imaging clinical diagnostics are not taken up into the tumor cells, but only accumulate in the interstitial space of the highly vasculated tumor. We examined the gastrin/cholecystokinin-B receptor as a possible target for prostate-specific detection using the C-terminal seven amino acid sequence of the gastrin peptide hormone. The correct sequence and a scrambled control sequence were coupled to the fluorescent dye rhodamine and the magnetic resonance imaging contrast agent gadolinium (Gd)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). Expression analysis of the gastrin receptor mRNA was performed by reverse transcriptase polymerase chain reaction on PC3 prostate carcinoma cells, U373 glioma, U2OS osteosarcoma and Colo205 colon carcinoma cells. After having confirmed elevated expression of gastrin receptor in PC3 cells and very low expression of the receptor in Colo205 cells, these two cell lines were used to create tumor xenografts on nude mice for in vivo experiments. Confocal lasers scanning microscopy and magnetic resonance imaging showed a high specificity of the correct conjugate for the PC3 xenografts. Staining of the PC3 xenografts was much weaker with the scrambled conjugate while the Colo205 xenografts showed no marked staining with any of the conjugates. In vitro experiments comparing the correct and scrambled conjugates on PC3 cells by magnetic resonance relaxometry and fluorescence-activated cell sorting confirmed markedly higher specificity of the correct conjugate. The investigations show that the gastrin receptor is a promising tumor cell surface target for future prostate-cancer-specific imaging applications.

Topics: Animals; Cell Line, Tumor; Contrast Media; Fluorescent Dyes; Gadolinium; Gastrins; Heterocyclic Compounds, 1-Ring; Humans; Magnetic Resonance Imaging; Male; Mice; Mice, Nude; Oligopeptides; Prostate; Prostatic Neoplasms; Receptor, Cholecystokinin B; Rhodamines

Neuroendocrine differentiated tumor cells (NETC) can be found in a large portion of prostate carcinoma (PCa) specimens. This is the first study to systematically quantify and analyze the influence of the NETC distribution and of their secretory products, serotonin, bombesin, and gastrin, on angiogenesis and in the clinical follow-up of PCa patients.. 175 PCa specimens were included in this study. NETC were displayed using the marker CgA. Specimens showing a high expression of CgA were analyzed for serotonin, bombesin, and gastrin. Blood vessels were stained with the epitope CD34. Data was analyzed for inter-correlation and its correlation to clinical-pathological parameters and the results of a mid-term follow-up.. The number of NETC was correlated with the pT-status and the Gleason score. Specimens with high NETC expression had an increased microvessel density (MVD). No correlation between the neurosecretory products and the clinical-pathological parameters was found. High NETC expression, high bombesin expression and increased MVD were associated with early treatment failure in the follow-up.. NETC have an influence on angiogenesis and are correlated with the clinical-pathological parameters. A high expression of NETC is associated with an early failure of treatment. Our study underlines the importance of NETC in prostate cancer.

Topics: Aged; Biomarkers, Tumor; Bombesin; Carcinoma, Neuroendocrine; Cell Differentiation; Follow-Up Studies; Gastrins; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Neoplasm Grading; Neoplasm Staging; Neovascularization, Pathologic; Prostate; Prostatic Neoplasms; Risk Factors; Serotonin

Increases in neuroendocrine phenotype and secretory products are closely correlated with tumor progression and androgen independence in prostate cancer. In this study, we explored this correlation using serum progastrin-releasing peptide (ProGRP), a carboxy-terminal region common to three subtypes of precursors for gastrin-releasing peptide (GRP), which is released from the neuroendocrine phenotype to act as a growth factor.. In 60 patients with benign prostatic hyperplasia (BPH) and 200 with prostate cancer, serum ProGRP levels were determined with an enzyme-linked immunosorbent assay (ELISA) kit and evaluated in relation to clinical stage, hormonal treatment, and prostate-specific antigen (PSA) values. Fourteen randomly selected patients were entered in the follow-up study. Additionally, expression of ProGRP as determined by immunohistochemical analysis was compared to that of chromogranin-A (CgA) in tissue samples from several subjects.. We found a positive correlation between PSA and ProGRP in patients with untreated prostate cancer; no correlation was found in the treated groups. The increases in the ProGRP value and in the percentage of patients with higher than normal values were significant (P < 0.0001), especially in the androgen-independent group (P < 0.0001). A longitudinal study showed that, in a subset of patients, the ProGRP values tended to increase transiently when the cancer became androgen independent, but remained unchanged or decreased at the androgen-dependent stage. Positive staining for ProGRP occurred in a different distribution in neuroendocrine tissues than that of staining for CgA.. The clinical results demonstrated the existence of a regulatory mechanism for GRP, which to date had only been observed in cell lines. These findings suggest that GRP is a growth factor potentially upregulated by androgen but that does not rely principally on androgen modulation. The large overlap in levels of ProGRP among the groups limits the use of this value as a monitoring tool. Measurement of ProGRP, however, does have potential as an independent parameter to evaluate androgen-independent progression and to facilitate a new therapeutic strategy that may compensate for current limitations of diagnosis based on PSA alone.

Topics: Adult; Aged; Androgens; Biomarkers, Tumor; Disease Progression; Enzyme-Linked Immunosorbent Assay; Gastrin-Releasing Peptide; Gastrins; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Longitudinal Studies; Male; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Peptide Fragments; Peptides; Phenotype; Prostate-Specific Antigen; Prostatic Neoplasms; Protein Precursors; Recombinant Proteins; Up-Regulation

Measurement of gastrin in serum or plasma in patients with gastrinoma may be complicated by the presence of circulating biosynthetic intermediates which may not be detected by commonly available immunoassays. In contrast, the "processing-independent analysis" of gastrins developed by professor Jens Rehfeld et al in Copenhagen detects gastrin forms irrespective of their size. The authors review gastrinoma pathophysiology, the biochemistry of gastrin and other biomarkers of gastrinoma, the differential diagnosis of hypergastrinemia as well as other methods currently employed in the workup of gastrinoma patients, and illustrate with a clinical case.

Topics: Biomarkers, Tumor; Diagnosis, Differential; Gastrinoma; Gastrins; Humans; International Cooperation; Male; Middle Aged; Multiple Endocrine Neoplasia Type 1; Practice Guidelines as Topic; Prostatic Neoplasms; Quality Assurance, Health Care; Radionuclide Imaging; Scandinavian and Nordic Countries

The diagnosis of adenocarcinoid (mucinous/goblet cell carcinoid) is usually unexpected by both clinicians and pathologists. We report here the case of a 74-year-old man with gastric lymphoma (B-cell MALToma) diagnosed by endoscopy, who was found on exploratory laparotomy also to have extensive intraabdominal involvement by adenocarcinoid, arising from the ileum and/or appendix. The patient died two years after diagnosis with bladder outlet and small bowel obstruction due to diffuse metastases. In addition to mucin positivity, immunohistochemical stains demonstrated the tumor to be positive for chromogranin, synaptophysin, serotonin, gastrin, and glucagon. Of histogenetic interest, some individual neoplastic cells appeared to be positive for both mucin and chromogranin, and this was confirmed by the electron microscopic finding of microvilli, intracytoplasmic mucin droplets, and neurosecretory granules involving the same neoplastic cells. This also appears to be the first reported case of adenocarcinoid associated with lymphoma and demonstration of histochemical/immunohistochemical and ultrastructural evidence of cellular components with dual mucinous adenocarcinoma and neuroendocrine features, and the second reported case to have prostatic metastases.

Topics: Adenocarcinoma; Aged; Appendiceal Neoplasms; Biomarkers, Tumor; Carcinoembryonic Antigen; Carmine; Chromogranins; Coloring Agents; Gastrins; Glucagon; Helicobacter Infections; Helicobacter pylori; Humans; Ileal Neoplasms; Immunohistochemistry; Laparotomy; Lymphoma, B-Cell, Marginal Zone; Male; Metaplasia; Microscopy, Electron; Neoplasms, Multiple Primary; Prostatic Neoplasms; Serotonin; Stomach Neoplasms; Synaptophysin

Hormones like bombesin (BN)/gastrin-releasing peptide (GRP) and luteinizing hormone-releasing hormone (LH-RH) and growth factors such as epidermal growth factor (EGF) might be involved in the relapse of prostate cancer under androgen ablation therapy. Interference with receptors for BN/GRP, LH-RH, or EGF might provide a therapeutic approach to inhibit tumor growth of androgen-independent prostate cancer.. LH-RH antagonist Cetrorelix (SB-75) and the BN/GRP antagonist RC-3940-II were tested for their effects on the growth of the androgen-independent PC-3 human prostate cancer cell line xenografted into nude mice. Tumor growth, serum hormone levels, and receptor concentrations for BN/GRP and EGF were measured.. When the treatment was started, tumor volume in all groups was 70-80 mm3. After 4 weeks, tumor volume in the control animals injected with saline was 871 +/- 233 mm3 and that of animals treated with Cetrorelix only 197 +/- 61 mm3. The BN/GRP antagonist RC-3940-II also significantly reduced PC-3 tumor volume in nude mice to 122 +/- 20 mm3. The combination of Cetrorelix and RC-3940-II produced no additional inhibition. High-affinity receptors for EGF were detected in the tumor membranes and their number was significantly decreased after administration of Cetrorelix or RC-3940-II.. These findings demonstrate that LH-RH antagonists and BN/GRP antagonists inhibit the growth of the androgen-independent prostate cancer cell line PC-3 in vivo. Both analogs may exert a direct inhibitory effect on tumor growth through a down-regulation of EGF receptors.

Topics: Animals; Antineoplastic Agents; Bombesin; Cell Division; DNA, Neoplasm; Drug Combinations; ErbB Receptors; Gastrins; Gonadotropin-Releasing Hormone; Hormone Antagonists; Humans; Luteinizing Hormone; Male; Mice; Mice, Nude; Neoplasm Transplantation; Peptide Fragments; Prostate; Prostatic Neoplasms; Receptors, Bombesin; Testosterone; Thymidine; Tumor Cells, Cultured

The aim of this study was to test the antagonist of LH-RH (Cetrorelix), agonist [D-Trp6]LH-RH (triptorelin) and new bombesin antagonists RC-3940-II and RC-3950-II for their effect on the growth of an androgen-independent prostate cancer cell line, DU-145, xenografted into nude mice. Xenografts were grown in male nude mice, and after 4 weeks, the animals were treated either with saline (control) or with one of the analogues. One group of mice was given a combination of Cetrorelix and RC-3950-II. Treatment was given for 4 weeks. Tumour and body weights, and tumour volumes were measured. At sacrifice, tumours were dissected for histological examination and receptor studies. Serum was collected for measurement of hormone levels. The final tumour volume in control animals injected with saline was 577 +/- 155 mm3 and that of animals treated with Cetrorelix only 121.4 +/- 45 mm3 (P < 0.01). Bombesin antagonists RC-3940-II and RC-3950-II also significantly reduced DU-145 tumour volume in nude mice to 84.9 +/- 19.9 and 96.8 +/- 28 mm3, respectively. Agonist [D-Trp6]LH-RH did not significantly inhibit tumour growth. Serum levels of LH were decreased to 0.08 +/- 0.02 ng/ml (P < 0.05) in the Cetrorelix treated group as compared to 1.02 +/- 0.1 ng/ml for the controls, and testosterone levels were reduced to castration levels (0.01 +/- 0.01 ng/ml). Specific receptors for EGF and LH-RH in DU-145 tumours were significantly downregulated after treatment with Cetrorelix, RC-3940-II and RC-3950-II. Although LH-RH could be a local regulator of growth of prostate cancer, the fall in LH-RH receptors is not fully understood and the inhibitory effects of Cetrorelix and bombesin antagonists on DU-145 tumour growth might be attributed at least in part to a downregulation of EHF receptors. Since Cetrorelix and bombesin antagonists inhibit growth of androgen-independent DU-145 prostate cancers, these compounds could be considered for the therapy of advanced prostate cancer in men, especially after relapse.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Body Weight; Bombesin; ErbB Receptors; Gastrins; Genitalia, Male; Gonadotropin-Releasing Hormone; Humans; Luteinizing Hormone; Male; Mice; Mice, Nude; Peptide Fragments; Prostatic Neoplasms; Receptors, Bombesin; Receptors, LHRH; Testosterone; Transplantation, Heterologous; Tumor Cells, Cultured

The effects of somatostatin analogue RC-160 and bombesin/gastrin releasing-peptide (GRP) antagonist RC-3095 were evaluated in Copenhagen rats bearing the anaplastic, androgen-independent Dunning R3327-AT-1 prostatic adenocarcinoma. In the first experiment, RC-160 was given in the form of microcapsules releasing 60 micrograms/day/rat. RC-3095 was administered from implanted Alzet osmotic minipumps liberating 100 micrograms/day/rat. After 32 days, tumor volumes and weights were significantly reduced by RC-160 as compared with the control group. Tumor doubling time in rats treated with RC-160 was significantly longer than in controls. Bombesin/GRP antagonist RC-3095 also significantly reduced tumor volume after 7 days of treatment, but after 18 days the inhibition in tumor volume was no longer significant. Tumor growth was not suppressed by castration. In the second experiment, 3-mm3 fragments of Dunning R-3327-AT-1 tumor were implanted orthotopically into the prostates of Copenhagen rats in order to evaluate the survival time of animals bearing this cancer during treatment with RC-160 released from Alzet osmotic minipumps at a dose of 100 micrograms/day/rat. Treatment with RC-160 significantly (P < 0.05) prolonged the mean survival time of rats by 5.3 days as compared to control animals. In both experiments, therapy with RC-160 significantly decreased serum growth hormone or insulin-like growth factor I levels. In the first experiment, receptor assays on R-3327-AT-1 tumor membranes showed high affinity binding sites for somatostatin, bombesin, and epidermal growth factor. At the end of the treatment, receptors for epidermal growth factor were significantly down-regulated by treatment with RC-160 but not with RC-3095. The binding capacity of bombesin receptors was reduced to nondetectable levels after the treatment with RC-3095. In cell cultures, high affinity binding sites for bombesin/GRP were found on intact Dunning R-3327-AT-1 cells, but receptors for somatostatin could not be detected. Proliferation of the AT-1 cell line was significantly inhibited by antagonist RC-3095. However, no effect on tumor cell growth in vitro was observed with analogue RC-160. Our results demonstrate that somatostatin analogue RC-160 and bombesin/GRP antagonist RC-3095 can inhibit the growth of the androgen-independent Dunning R-3327-AT-1 prostatic cancer in rats, although the remission produced by RC-3095 may be of short duration due to a down-regulation of bombesin receptors

Topics: Amino Acid Sequence; Animals; Antineoplastic Agents; Bombesin; Castration; Cell Division; Drug Screening Assays, Antitumor; ErbB Receptors; Gastrins; Growth Hormone; Male; Molecular Sequence Data; Neoplasm Transplantation; Peptide Fragments; Prostatic Neoplasms; Rats; Somatostatin

Specific receptors for bombesin/gastrin releasing peptide (GRP) on the androgen-independent human prostate cancer cell lines PC-3 and DU-145 were characterized. No specific binding of 125I-[Tyr4]-bombesin to the androgen-dependent human prostate cancer cell line LNCaP was detectable. The binding of 125I-[Tyr4]-bombesin to PC-3 and DU-145 cells was found to be time- and temperature-dependent, saturable, and reversible. Scatchard analysis revealed a single class of binding sites with high affinity (Kd 9.8 x 10(-11) M for PC-3, and 9.1 x 10(-11) M for DU-145 cells at 25 degrees C) and with a binding capacity of 44,000 binding sites/cell and 19,000 binding sites/cell, respectively. Bound 125I-[Tyr4]-bombesin was rapidly internalized by PC-3 cells. The nonhydrolyzable GTP analog GTP-gamma-S caused a dose-dependent inhibition of 125I-[Tyr4]-bombesin binding to PC-3 and DU-145 cells, indicating that a G-protein (guanine nucleotide-binding protein) couples the bombesin receptor to intracellular effector systems. Bombesin and GRP(14-27) inhibited the binding of 125I-[Tyr4]-bombesin to both cell lines in a dose-dependent manner with inhibition constants (Ki) of 0.5 nM and 0.4 nM, respectively. Both cell lines express the bombesin/GRP preferring bombesin receptor subtype, since, in displacement studies, neuromedin B was more than 200 times less potent than bombesin and GRP(14-27) in inhibiting the binding of 125I-[Tyr4]-bombesin. Two synthetic bombesin/GRP antagonists, RC-3095 and RC-3110, powerfully inhibited the specific binding of 125I-[Tyr4]-bombesin with Ki 0.92 nM and 0.26 nM on PC-3 cells, and 3.3 nM and 0.89 nM on DU-145 cells, respectively. These findings indicate that the PC-3 and DU-145 human prostate cancer cell lines possess specific high-affinity receptors for bombesin/GRP, and are suitable models for the evaluation of the antineoplastic activity of new bombesin/GRP antagonists in the treatment of androgen-independent prostate cancer.

Topics: Bombesin; Gastrin-Releasing Peptide; Gastrins; GTP-Binding Proteins; Humans; Iodine Radioisotopes; Male; Peptides; Prostatic Neoplasms; Receptors, Bombesin; Time Factors; Tumor Cells, Cultured

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

Nude mice bearing xenografts of the androgen-independent human prostate cancer DU-145 were treated for 4-5 weeks with somatostatin analog RC-160 or the bombesin/gastrin-releasing peptide (GRP) antagonist RC-3095. Tumor growth in animals treated with somatostatin analog RC-160 at a dose of 100 micrograms/day s.c. was significantly inhibited within 14 days of the start of the experiment. At necropsy, in mice given RC-160, tumor weight and volume were significantly decreased compared with control mice. Treatment with RC-3095 at a dose of 20 micrograms/day s.c. also suppressed tumor growth, the inhibition being significant after 2 weeks, but the reduction in tumor volume and weight was smaller than that produced by RC-160. Therapy with RC-160 significantly decreased serum growth hormone and gastrin levels. Specific binding sites for bombesin, somatostatin and epidermal growth factor (EGF) were found in the DU-145 tumor membranes. Receptors for EGF were significantly down-regulated after therapy with RC-3095 and RC-160. The finding that somatostatin analog RC-160 and bombesin/GRP antagonist RC-3095 inhibit the growth of androgen-independent prostate tumors in mice might be of practical importance for human prostate cancer therapy.

Topics: Amino Acid Sequence; Androgens; Animals; Binding Sites; Body Weight; Bombesin; Cell Line; Gastrin-Releasing Peptide; Gastrins; Growth Hormone; Humans; Male; Mice; Mice, Nude; Molecular Sequence Data; Peptide Fragments; Peptides; Prostatic Neoplasms; Somatostatin