ABSTRACT
Chimeric somatostatin/dopamine compounds such as BIM-23A760, an sst2/sst5/D2 receptors-agonist, have emerged as promising new approaches to treat pituitary adenomas. However, information on direct in vitro effects of BIM-23A760 in normal and tumoral pituitaries remains incomplete. The objective of this study was to analyze BIM-23A760 effects on functional parameters (Ca2+ signaling, hormone expression/secretion, cell viability and apoptosis) in pituitary adenomas (n = 74), and to compare with the responses of normal primate and human pituitaries (n = 3-5). Primate and human normal pituitaries exhibited similar sst2/sst5/D2 expression patterns, wherein BIM-23A760 inhibited the expression/secretion of several pituitary hormones (specially GH/PRL), which was accompanied by increased sst2/sst5/D2 expression in primates and decreased Ca2+ concentration in human cells. In tumoral pituitaries, BIM-23A760 also inhibited Ca2+ concentration, hormone secretion/expression and proliferation. However, BIM-23A760 elicited stimulatory effects in a subset of GHomas, ACTHomas and NFPAs in terms of Ca2+ signaling and/or hormone secretion, which was associated with the relative somatostatin/dopamine-receptors levels, especially sst5 and sst5TMD4. The chimeric sst2/sst5/D2 compound BIM-23A760 affects multiple, clinically relevant parameters on pituitary adenomas and may represent a valuable therapeutic tool. The relative ssts/D2 expression profile, particularly sst5 and/or sst5TMD4 levels, might represent useful molecular markers to predict the ultimate response of pituitary adenomas to BIM-23A760.
Subject(s)
Adenoma/metabolism , Dopamine Agonists/pharmacology , Dopamine/analogs & derivatives , Pituitary Gland/drug effects , Pituitary Neoplasms/metabolism , Somatostatin/analogs & derivatives , Adolescent , Adult , Aged , Animals , Apoptosis , Calcium Signaling , Cell Survival , Cells, Cultured , Dopamine/pharmacology , Exocytosis , Female , Humans , Male , Middle Aged , Papio , Pituitary Gland/cytology , Pituitary Gland/metabolism , Receptors, Dopamine/genetics , Receptors, Dopamine/metabolism , Receptors, Somatostatin/genetics , Receptors, Somatostatin/metabolism , Somatostatin/pharmacologyABSTRACT
CONTEXT: In Cushing's disease, ACTH hypersecretion by pituitary corticotrope adenoma cells and resulting hypercortisolism is accompanied by a severely blunted GH secretory response. Interestingly, in Cushing's disease, ghrelin markedly increases plasma ACTH, whereas its stimulatory action on GH secretion is reduced. Although the reported expression of ghrelin receptors (GHS-R) in corticotrope tumors offers a potential mechanism for ghrelin-induced ACTH hypersecretion, studies on the direct effects of synthetic GH secretagogues on corticotropinoma cells offered contradictory results. OBJECTIVE AND DESIGN: To evaluate the direct action of ghrelin on corticotropinoma cells from two patients with Cushing's disease, we measured its effect on free cytosolic calcium concentration ([Ca(2+)](i)). Additionally, expression of GHS-R and its ligand ghrelin was examined in these cells and in five additional corticotropinomas. RESULTS: Ghrelin (10(-6) m) induced a marked [Ca(2+)](i) increase in 89.5% (case 1; n = 19 cells) and 85% (case 2; n = 13 cells) of corticotropinoma cells. Moreover, RT-PCR showed that expression of GHS-R isoforms is accompanied by that of ghrelin in all seven corticotrope adenomas examined. Importantly, double immunogold electron microscopy revealed that ghrelin is costored within ACTH secretory vesicles in densely granulated adenomatous corticotropes. CONCLUSIONS: These results constitute the first demonstration that ghrelin acts directly on corticotrope tumor cells derived from patients with Cushing's disease. The presence of ghrelin and GHS-R suggests that pituitary ghrelin may play an autocrine/paracrine role in regulating ACTH release in Cushing's disease. Our findings provide a plausible cellular basis for the exaggerated ACTH response to ghrelin in Cushing's disease and suggest novel research strategies to develop medical treatments for this disease.
Subject(s)
Adenoma/metabolism , Adrenocorticotropic Hormone/metabolism , Peptide Hormones/physiology , Pituitary Neoplasms/metabolism , Adult , Calcium/metabolism , Female , Fluorescent Antibody Technique , Ghrelin , Humans , Immunohistochemistry , Pro-Opiomelanocortin/genetics , RNA, Messenger/analysis , Receptors, G-Protein-Coupled/genetics , Receptors, GhrelinABSTRACT
Somatostatin analogs (SSA) are the mainstay of pharmacological treatment for pituitary adenomas. However, some patients escape from therapy with octreotide, a somatostatin receptor 2 (sst2)-preferring SSA, and pasireotide, a novel multi-sst-preferring SSA, may help to overcome this problem. It has been proposed that correspondence between sst1-sst5 expression pattern and SSA-binding profile could predict patient's response. To explore the cellular/molecular features associated with octreotide/pasireotide response, we performed a parallel comparison of their in vitro effects, evaluating sst1-sst5 expression, intracellular Ca2+ signaling ([Ca2+]i), hormone secretion and cell viability, in a series of 85 pituitary samples. Somatotropinomas expressed sst5>sst2, yet octreotide reduced [Ca2+]i more efficiently than pasireotide, while both SSA similarly decreased growth hormone release/expression and viability. Corticotropinomas predominantly expressed sst5, but displayed limited response to pasireotide, while octreotide reduced functional endpoints. Non-functioning adenomas preferentially expressed sst3 but, surprisingly, both SSA increased cell viability. Prolactinomas mainly expressed sst1 but were virtually unresponsive to SSA. Finally, both SSA decreased [Ca2+]i in normal pituitaries. In conclusion, both SSA act in vitro on pituitary adenomas exerting both similar and distinct effects; however, no evident correspondence was found with the sst1-sst5 profile. Thus, it seems plausible that additional factors, besides the simple abundance of a given sst, critically influence the SSA response.
Subject(s)
Antineoplastic Agents, Hormonal/pharmacology , Neoplasm Proteins/agonists , Octreotide/pharmacology , Pituitary Gland/drug effects , Pituitary Neoplasms/drug therapy , Receptors, Somatostatin/agonists , Somatostatin/analogs & derivatives , ACTH-Secreting Pituitary Adenoma/drug therapy , ACTH-Secreting Pituitary Adenoma/metabolism , ACTH-Secreting Pituitary Adenoma/pathology , Adenoma/drug therapy , Adenoma/metabolism , Adenoma/pathology , Antineoplastic Agents, Hormonal/adverse effects , Calcium Signaling/drug effects , Cell Survival/drug effects , Cells, Cultured , Drug Resistance, Neoplasm , Female , Gene Expression Regulation, Neoplastic/drug effects , Growth Hormone-Secreting Pituitary Adenoma/drug therapy , Growth Hormone-Secreting Pituitary Adenoma/metabolism , Growth Hormone-Secreting Pituitary Adenoma/pathology , Humans , Male , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Octreotide/adverse effects , Pituitary Gland/metabolism , Pituitary Gland/pathology , Pituitary Neoplasms/metabolism , Pituitary Neoplasms/pathology , Prolactinoma/drug therapy , Prolactinoma/metabolism , Prolactinoma/pathology , Protein Isoforms/agonists , Protein Isoforms/genetics , Protein Isoforms/metabolism , Receptors, Somatostatin/genetics , Receptors, Somatostatin/metabolism , Somatostatin/adverse effects , Somatostatin/pharmacology , Tumor Cells, CulturedABSTRACT
Pituitary adenomas comprise a heterogeneous subset of pathologies causing serious comorbidities, which would benefit from identification of novel, common molecular/cellular biomarkers and therapeutic targets. The ghrelin system has been linked to development of certain endocrine-related cancers. Systematic analysis of the presence and functional implications of some components of the ghrelin system, including native ghrelin, receptors and the recently discovered splicing variant In1-ghrelin, in human normal pituitaries (n = 11) and pituitary adenomas (n = 169) revealed that expression pattern of ghrelin system suffers a clear alteration in pituitary adenomasas compared with normal pituitary, where In1-ghrelin is markedly overexpressed. Interestingly, in cultured pituitary adenoma cells In1-ghrelin treatment (acylated peptides at 100 nM; 24-72 h) increased GH and ACTH secretion, Ca(2+) and ERK1/2 signaling and cell viability, whereas In1-ghrelin silencing (using a specific siRNA; 100â nM) reduced cell viability. These results indicate that an alteration of the ghrelin system, specially its In1-ghrelin variant, could contribute to pathogenesis of different pituitary adenomas types, and suggest that this variant and its related ghrelin system could provide new tools to identify novel, more general diagnostic, prognostic and potential therapeutic targets in pituitary tumors.
Subject(s)
Adenoma/genetics , Gene Expression Regulation, Neoplastic , Ghrelin/genetics , Pituitary Neoplasms/genetics , Adenoma/metabolism , Adenoma/pathology , Adrenocorticotropic Hormone/metabolism , Alternative Splicing , Animals , Apoptosis/drug effects , Blotting, Western , CHO Cells , Cell Line, Tumor , Cricetinae , Cricetulus , Extracellular Signal-Regulated MAP Kinases/metabolism , Ghrelin/metabolism , Growth Hormone/metabolism , Humans , Introns/genetics , Molecular Sequence Data , Peptides/metabolism , Peptides/pharmacology , Pituitary Neoplasms/metabolism , Pituitary Neoplasms/pathology , Protein Isoforms/genetics , Protein Isoforms/metabolism , Proto-Oncogene Proteins c-akt/metabolism , RNA Interference , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Tumor Cells, CulturedABSTRACT
A case of hypertrophic cranial pachymeningitis associated with Sweet's Syndrome is presented. Both entities have been described in association with several other chronic systemic inflammatory diseases and autoimmune conditions. To our knowledge the coexistence between Sweet's Syndrome and hypertrophic cranial pachymeningitis has not been reported up to date. We suggest a possible autoimmune or dysimmune mechanism in the pathogenesis of these two entities.
Subject(s)
Dura Mater/pathology , Meningitis/complications , Meningitis/pathology , Sweet Syndrome/complications , Adult , Humans , Hypertrophy , Magnetic Resonance Imaging , Meningitis/diagnosis , Meningitis/surgery , Tomography, X-Ray ComputedABSTRACT
The locomotor pattern alterations produced after the administration of a sublingual detomidine gel was measured by an accelerometric method in horses. Using a randomized two-way crossover design, all animals (n = 6) randomly received either detomidine gel or a placebo administered sublingually. A triaxial accelerometric device was used for gait assessment 15 minutes before (baseline) and every 10 minutes after each treatment for a period of 180 minutes. Eight different parameters were calculated, including speed, stride frequency, stride length, regularity, dorsoventral, propulsion, mediolateral, and total power. Force of acceleration and the three components of power were also calculated. Significant statistical differences were observed between groups in all the parameters but stride length. The majority of significant changes started between 30 and 70 minutes after drug administration and lasted for 160 minutes. This route of administration is definitely useful in horses in which a prolonged sedation is required, with stability being a major concern.
Subject(s)
Accelerometry/veterinary , Gait/drug effects , Horses/physiology , Hypnotics and Sedatives/pharmacology , Imidazoles/pharmacology , Accelerometry/methods , Administration, Sublingual , Animals , Cross-Over Studies , Gait/physiology , Gels , Hypnotics and Sedatives/administration & dosage , Imidazoles/administration & dosage , Locomotion/drug effects , Locomotion/physiology , Time Factors , Treatment OutcomeABSTRACT
CONTEXT: KISS1 was originally identified as a metastasis-suppressor gene able to inhibit tumor progression. KISS1 gene products, the kisspeptins, bind to a G-protein-coupled receptor (KISS1R, formerly GPR54), which is highly expressed in placenta, pituitary, and pancreas, whereas KISS1 mRNA is mainly expressed in placenta, hypothalamus, striatum, and pituitary. OBJECTIVE AND DESIGN: KISS1/KISS1R pituitary expression profile, coupled to their anti-tumoral capacities, led us to hypothesize that this system may be involved in the biology of pituitary tumors. To explore this notion, expression levels of KISS1R and KISS1 were evaluated in normal and adenomatous pituitaries. Additionally, functionality of this system was assessed by treating dispersed pituitary adenoma cells in primary culture with kisspeptin-10 and evaluating intracellular calcium kinetics and apoptotic rate. RESULTS: Both KISS1 and KISS1R were expressed in normal pituitary, whereas this simultaneous expression was frequently lost in pituitary tumors, where diverse patterns of KISS1/KISS1R expression were observed that differed among distinct types of pituitary adenomas. Measurement of calcium kinetics revealed that kisspeptin-10 elicits a remarkable increase in [Ca(2+)](i) in individual cells from four out of the five GH-producing adenomas studied, whereas cells derived from non-functioning pituitary adenomas (NFPA, n=45) did not respond. In contrast, kisspeptin-10 treatment increased the apoptotic rate in cells derived from both GH-producing and NFPA. CONCLUSIONS: These results provide primary evidence that KISS1 and KISS1R expression can be differentially lost in pituitary tumor subtypes, where this system can exert functional, proapoptotic actions, and thereby offer novel insights to investigate the biology and therapeutic options to treat these tumors.