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Dalle Nogare M, D'Annunzio S, Vazza G, Regazzo D, Picello L, Denaro L, Voltan G, Scaroni C, Ceccato F, Occhi G. The Methylation Analysis of the Glucose-Dependent Insulinotropic Polypeptide Receptor (GIPR) Locus in GH-Secreting Pituitary Adenomas. Int J Mol Sci 2023; 24:ijms24119264. [PMID: 37298217 DOI: 10.3390/ijms24119264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023] Open
Abstract
The glucose-dependent insulinotropic polypeptide receptor (GIPR) is aberrantly expressed in about one-third of GH-secreting pituitary adenomas (GH-PAs) and has been associated with a paradoxical increase of GH after a glucose load. The reason for such an overexpression has not yet been clarified. In this work, we aimed to evaluate whether locus-specific changes in DNA methylation patterns could contribute to this phenomenon. By cloning bisulfite-sequencing PCR, we compared the methylation pattern of the GIPR locus in GIPR-positive (GIPR+) and GIPR-negative (GIPR-) GH-PAs. Then, to assess the correlation between Gipr expression and locus methylation, we induced global DNA methylation changes by treating the lactosomatotroph GH3 cells with 5-aza-2'-deoxycytidine. Differences in methylation levels were observed between GIPR+ and GIPR- GH-PAs, both within the promoter (31.9% vs. 68.2%, p < 0.05) and at two gene body regions (GB_1 20.7% vs. 9.1%; GB_2 51.2% vs. 65.8%, p < 0.05). GH3 cells treated with 5-aza-2'-deoxycytidine showed a ~75% reduction in Gipr steady-state level, possibly associated with the observed decrease in CpGs methylation. These results indicate that epigenetic regulation affects GIPR expression in GH-PAs, even though this possibly represents only a part of a much more complex regulatory mechanism.
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Affiliation(s)
| | - Sarah D'Annunzio
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Giovanni Vazza
- Department of Biology, University of Padova, 35128 Padova, Italy
| | - Daniela Regazzo
- Endocrinology Unit, Department of Medicine, Padova University Hospital, 35121 Padova, Italy
| | - Luna Picello
- Department of Biology, University of Padova, 35128 Padova, Italy
| | - Luca Denaro
- Academic Neurosurgery, Department of Neurosciences, Padova University Hospital, 35121 Padova, Italy
| | - Giacomo Voltan
- Endocrinology Unit, Department of Medicine, Padova University Hospital, 35121 Padova, Italy
| | - Carla Scaroni
- Endocrinology Unit, Department of Medicine, Padova University Hospital, 35121 Padova, Italy
| | - Filippo Ceccato
- Endocrinology Unit, Department of Medicine, Padova University Hospital, 35121 Padova, Italy
| | - Gianluca Occhi
- Department of Biology, University of Padova, 35128 Padova, Italy
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2
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Santoro M, De Amicis F, Aquila S, Bonofiglio D. Peroxisome proliferator-activated receptor gamma expression along the male genital system and its role in male fertility. Hum Reprod 2020; 35:2072-2085. [PMID: 32766764 DOI: 10.1093/humrep/deaa153] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) acts as a ligand activated transcription factor and regulates processes, such as energy homeostasis, cell proliferation and differentiation. PPARγ binds to DNA as a heterodimer with retinoid X receptor and it is activated by polyunsaturated fatty acids and fatty acid derivatives, such as prostaglandins. In addition, the insulin-sensitizing thiazolidinediones, such as rosiglitazone, are potent and specific activators of PPARγ. PPARγ is present along the hypothalamic-pituitary-testis axis and in the testis, where low levels in Leydig cells and higher levels in Sertoli cells as well as in germ cells have been found. High amounts of PPARγ were reported in the normal epididymis and in the prostate, but the receptor was almost undetectable in the seminal vesicles. Interestingly, in the human and in pig, PPARγ protein is highly expressed in ejaculated spermatozoa, suggesting a possible role of PPARγ signaling in the regulation of sperm biology. This implies that both natural and synthetic PPARγ ligands may act directly on sperm improving its performance. Given the close link between energy balance and reproduction, activation of PPARγ may have promising metabolic implications in male reproductive functions. In this review, we first describe PPARγ expression in different compartments of the male reproductive axis. Subsequently, we discuss the role of PPARγ in both physiological and several pathological conditions related to the male fertility.
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Affiliation(s)
- Marta Santoro
- Department of Pharmacy, Health and Nutritional Sciences (Department of Excellence, Italian Law 232/2016), Arcavacata di Rende, Cosenza 87036, Italy.,Centro Sanitario, University of Calabria, Arcavacata di Rende, Cosenza 87036, Italy
| | - Francesca De Amicis
- Department of Pharmacy, Health and Nutritional Sciences (Department of Excellence, Italian Law 232/2016), Arcavacata di Rende, Cosenza 87036, Italy
| | - Saveria Aquila
- Department of Pharmacy, Health and Nutritional Sciences (Department of Excellence, Italian Law 232/2016), Arcavacata di Rende, Cosenza 87036, Italy.,Centro Sanitario, University of Calabria, Arcavacata di Rende, Cosenza 87036, Italy
| | - Daniela Bonofiglio
- Department of Pharmacy, Health and Nutritional Sciences (Department of Excellence, Italian Law 232/2016), Arcavacata di Rende, Cosenza 87036, Italy.,Centro Sanitario, University of Calabria, Arcavacata di Rende, Cosenza 87036, Italy
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3
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Nuclear Receptors as Regulators of Pituitary Corticotroph Pro-Opiomelanocortin Transcription. Cells 2020; 9:cells9040900. [PMID: 32272677 PMCID: PMC7226830 DOI: 10.3390/cells9040900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 12/16/2022] Open
Abstract
The hypothalamic–pituitary–adrenal (HPA) axis plays a critical role in adaptive stress responses and maintaining organism homeostasis. The pituitary corticotroph is the central player in the HPA axis and is regulated by a plethora of hormonal and stress related factors that synergistically interact to activate and temper pro-opiomelanocortin (POMC) transcription, to either increase or decrease adrenocorticotropic hormone (ACTH) production and secretion as needed. Nuclear receptors are a family of highly conserved transcription factors that can also be induced by various physiologic signals, and they mediate their responses via multiple targets to regulate metabolism and homeostasis. In this review, we summarize the modulatory roles of nuclear receptors on pituitary corticotroph cell POMC transcription, describe the unique and complex role these factors play in hypothalamic–pituitary–adrenal axis (HPA) regulation and discuss potential therapeutic targets in disease states.
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Regazzo D, Losa M, Albiger NM, Terreni MR, Vazza G, Ceccato F, Emanuelli E, Denaro L, Scaroni C, Occhi G. The GIP/GIPR axis is functionally linked to GH-secretion increase in a significant proportion of gsp- somatotropinomas. Eur J Endocrinol 2017; 176:543-553. [PMID: 28179449 DOI: 10.1530/eje-16-0831] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/01/2017] [Accepted: 02/07/2017] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Glucose-dependent insulinotropic polypeptide receptor (GIPR) overexpression has been recently described in a proportion of gsp- somatotropinomas and suggested to be associated with the paradoxical increase of GH (GH-PI) during an oral glucose load. DESIGN AND METHODS This study was aimed at linking the GIP/GIPR pathway to GH secretion in 25 somatotropinomas-derived primary cultures and correlating molecular with clinical features in acromegalic patients. Given the impairment of the GIP/GIPR axis in acromegaly, an additional aim was to assess the effect of GH/IGF-1 stimulation on GIP expression in the enteroendocrine cell line STC-1. RESULTS Nearly 80% of GIPR-expressing somatotropinomas, all of them negative for gsp mutations, show increased GH secretion upon GIP stimulation, higher sensitivity to Forskolin but not to somatostatin analogs. Besides increased frequency of GH-PI, GIPR overexpression does not appear to affect acromegalic patients' clinical features. In STC-1 cells transfected with GIP promoter-driven luciferase vector, IGF-1 but not GH induced dose-dependent increase in luciferase activity. CONCLUSIONS We demonstrate that GIPR mediates the GH-PI in a significant proportion of gsp- acromegalic patients. In these cases, the stimulatory effect of IGF-1 on GIP promoter support the hypothesis of a functional GH/IGF-1/GIP axis. Further studies based on larger cohorts and the development of a stable transgenic model with inducible GIPR overexpression targeted to pituitary somatotroph lineage will be mandatory to establish the real role of GIPR in the pathogenesis of somatotropinomas.
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Affiliation(s)
- D Regazzo
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | - M Losa
- Pituitary UnitDepartment of Neurosurgery
| | - N M Albiger
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | - M R Terreni
- Pathology UnitIstituto Scientifico San Raffaele, Università Vita-Salute, Milano, Italy
| | - G Vazza
- Department of BiologyUniversity of Padova, Padova, Italy
| | - F Ceccato
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | | | - L Denaro
- Department of NeuroscienceHospital/University of Padova, Padova, Italy
| | - C Scaroni
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | - G Occhi
- Department of BiologyUniversity of Padova, Padova, Italy
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5
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Occhi G, Barollo S, Regazzo D, Bertazza L, Galuppini F, Guzzardo V, Jaffrain-Rea ML, Vianello F, Ciato D, Ceccato F, Watutantrige-Fernando S, Bisognin A, Bortoluzzi S, Pennelli G, Boscaro M, Scaroni C, Mian C. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC. Oncotarget 2016; 6:32104-14. [PMID: 26392334 PMCID: PMC4741662 DOI: 10.18632/oncotarget.5194] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/03/2015] [Indexed: 12/29/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice.
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Affiliation(s)
- Gianluca Occhi
- Department of Biology, University of Padova, Padova, Italy
| | - Susi Barollo
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Daniela Regazzo
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Loris Bertazza
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Francesca Galuppini
- Surgical Pathology & Cytopathology Unit, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Vincenza Guzzardo
- Surgical Pathology & Cytopathology Unit, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Marie Lise Jaffrain-Rea
- Department of Clinical and Biotechnological Sciences, University of L'Aquila, L'Aquila, Italy.,Neuromed Institute, Department of Neurological Sciences, University of L'Aquila, L'Aquila, Italy
| | - Federica Vianello
- Department of Radiotherapy, Istituto Oncologico del Veneto, IOV-IRCCS, Padova, Italy
| | - Denis Ciato
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Filippo Ceccato
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | | | | | | | - Gianmaria Pennelli
- Surgical Pathology & Cytopathology Unit, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Marco Boscaro
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Carla Scaroni
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Caterina Mian
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
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Abstract
INTRODUCTION Prolactinomas are the most common functional pituitary adenomas. Current classification systems rely on phenotypic elements and have few molecular markers for complementary classification. Treatment protocols for prolactinomas are also devoid of molecular targets, leaving those refractory to standard treatments without many options. METHODS A systematic literature review was performed utilizing the PRISMA guidelines. We aimed to summarize prior research exploring gene and protein expression in prolactinomas in order to highlight molecular variations associated with tumor development, growth, and prolactin secretion. A PubMed search of select MeSH terms was performed to identify all studies reporting gene and protein expression findings in prolactinomas from 1990 to 2014. RESULTS 1392 abstracts were screened and 51 manuscripts were included in the analysis, yielding 54 upregulated and 95 downregulated genes measured by various direct and indirect analytical methods. Of the many genes identified, three upregulated (HMGA2, HST, SNAP25), and three downregulated (UGT2B7, Let7, miR-493) genes were selected for further analysis based on our subjective identification of strong potential targets. CONCLUSIONS Many significant genes have been identified and validated in prolactinomas and most have not been fully analyzed for therapeutic and diagnostic potential. These genes could become candidate molecular targets for biomarker development and precision drug targeting as well as catalyze deeper research efforts utilizing next generation profiling/sequencing techniques, particularly genome scale expression and epigenomic analyses.
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Affiliation(s)
- Justin Seltzer
- Department of Neurosurgery, Keck School of Medicine of USC, 1200 North State St., Los Angeles, CA, 90033, USA.
| | - Thomas C Scotton
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Keiko Kang
- Department of Neurosurgery, Keck School of Medicine of USC, 1200 North State St., Los Angeles, CA, 90033, USA
| | - Gabriel Zada
- Department of Neurosurgery, Keck School of Medicine of USC, 1200 North State St., Los Angeles, CA, 90033, USA
- USC Pituitary Center, Keck School of Medicine of USC, Los Angeles, CA, USA
- Zilka Neurogenetics Institute, Keck School of Medicine of USC, Los Angeles, CA, USA
| | - John D Carmichael
- Division of Endocrinology, Department of Medicine, Keck School of Medicine of USC, Los Angeles, CA, USA
- USC Pituitary Center, Keck School of Medicine of USC, Los Angeles, CA, USA
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7
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Ceccato F, Scaroni C, Boscaro M. Clinical use of pasireotide for Cushing's disease in adults. Ther Clin Risk Manag 2015; 11:425-34. [PMID: 25834454 PMCID: PMC4370333 DOI: 10.2147/tcrm.s37314] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cushing’s disease Excessive corticotroph hormone levels sustained by an adrenocorticotropic hormone-secreting pituitary adenoma lead to a severe clinical condition caused by excess cortisol secretion, called Cushing’s disease (CD). Neurosurgery and radiotherapy are used to treat the pituitary adenoma directly, but new medical treatments targeting the corticotroph cells have recently become available. Pasireotide This is a novel multireceptor ligand somatostatin (SST) analog with a high binding affinity for SST receptor 5, the predominant receptor in human corticotroph adenomas that is not downregulated by high cortisol levels (as SST receptor 2 is). Pasireotide has been recently approved by the European Medical Agency and the US Food and Drug Administration for treating adults with CD with recurrent hypercortisolism after surgery, or for whom surgery is not an option. A dose of 600–1,200 μg twice a day can normalize urinary free cortisol levels after 3 months of treatment in up to 28% of patients, reducing their blood pressure and improving their weight, lipid profile, and quality of life. Combining pasireotide with cabergoline to achieve a greater hormone response can normalize cortisol secretion in 50% of patients, and adding ketoconazole induces biochemical control in most patients with CD. Safety and hyperglycemia The adverse effects of pasireotide are similar to those of other SST analogs, including diarrhea, nausea, and biliary sludge or gallstones. Hyperglycemia is common during pasireotide treatment, which affects the secretion of pancreatic insulin and intestinal glucagon-like peptide 1. Self-monitoring is essential to achieve good metabolic control, and endocrinologists should first administer metformin if insulin resistance is evident and then add dipeptidyl peptidase 4 inhibitors/glucagon-like peptide 1 receptor agonists or insulin. Conclusion In recent years, medical treatment with pasireotide has been proposed as monotherapy for adults with CD characterized by mild to moderate hypercortisolemia, as well as in combination with other available therapies. It is generally well-tolerated, but endocrinologists need to monitor glucose levels to ensure prompt treatment.
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Affiliation(s)
- Filippo Ceccato
- Endocrinology Unit, Department of Medicine, Padova University Hospital, Padova, Italy
| | - Carla Scaroni
- Endocrinology Unit, Department of Medicine, Padova University Hospital, Padova, Italy
| | - Marco Boscaro
- Endocrinology Unit, Department of Medicine, Padova University Hospital, Padova, Italy
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Ceccato F, Occhi G, Regazzo D, Randi ML, Cecchin D, Gardiman MP, Manara R, Lombardi G, Denaro L, Mantero F, Scaroni C. Gonadotropin secreting pituitary adenoma associated with erythrocytosis: case report and literature review. Hormones (Athens) 2014; 13:131-9. [PMID: 24722134 DOI: 10.1007/bf03401328] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Most pituitary adenomas with FSH- or LH-positive immunohistochemistry are endocrinologically silent, and neurological symptoms due to their large volume are the first clinical signs; they are rarely reported to be secreting gonadotropins, this usually occurring in cases with clinical endocrine findings. Gonadotropinomas are often treated surgically because they are unresponsive to conventional medical therapies. Temozolomide was recently recommended for non-responder aggressive pituitary adenoma management. CASE REPORT A 43-year-old male with a history of 5 years of erythrocytosis presented with severe headache, orthostatic dizziness, and difficulty walking. MRI documented a giant pituitary adenoma and high uptake of 111In-pentetreotide indicated somatostatin receptor (SSR) expression. Biochemical tests revealed a secreting gonadotropinoma. Therapy with somatostatin analogs and dopamine agonists improved the patient's headache, achieved partial hormone control, slightly reduced the size of the adenoma, and controlled erythrocytosis. Six months after the diagnosis, hormone escape occurred despite therapy, thus neurosurgery was performed. After the procedure the patient died of untreatable intracranial hypertension. The surgical specimen revealed SSR 2 and 3 expression, and temozolomide did not induce apoptosis in primary cell culture. REVIEW OF LITERATURE Among gonadotropinomas, female gender (77%), macroadenoma (84%), young age at diagnosis (28 ± 12 years), delay from first symptoms to diagnosis (up to 15 years), and ovarian cysts/menstrual disorders in females or macro-orchidism in males were the foremost clinical and neuroimaging features. CONCLUSIONS Male gonadotropin-secreting pituitary adenomas may have a variable clinical expression secondary to testosterone excess. Somatostatin analogs, dopamine agonists or temozolomide may have a role that needs to be assessed case by case.
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Affiliation(s)
- Filippo Ceccato
- Endocrinology Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Gianluca Occhi
- Endocrinology Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Daniela Regazzo
- Endocrinology Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Maria Luigia Randi
- Internal Medicine, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Diego Cecchin
- Nuclear Medicine Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Marina Paola Gardiman
- Surgical Pathology and Cytopathology Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Renzo Manara
- Neuroradiologic Unit, University Hospital of Padua, Padua, Italy
| | - Giuseppe Lombardi
- Medical Oncology 1, Venetian Oncology Institute - IRCCS, Padua, Italy
| | - Luca Denaro
- Neurosurgery Division, University Hospital of Padua; Padua, Italy
| | - Franco Mantero
- Endocrinology Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
| | - Carla Scaroni
- Endocrinology Unit, Department of Medicine DIMED; University of Padua Medical School, Padua, Italy
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Miller BA, Rutledge WC, Ioachimescu AG, Oyesiku NM. Management of large aggressive nonfunctional pituitary tumors: experimental medical options when surgery and radiation fail. Neurosurg Clin N Am 2013; 23:587-94. [PMID: 23040745 DOI: 10.1016/j.nec.2012.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pituitary adenomas are generally considered benign tumors; however, a subset of these tumors displays aggressive behavior and are not easily cured. The protocol for nonsurgical treatment of aggressive pituitary lesions is less standardized than that of other central nervous system tumors. Aggressive surgical treatment, radiation, dopamine agonists, antiangiogenic drugs, and other chemotherapeutics all have roles in the treatment of aggressive pituitary tumors. More studies are needed to improve outcomes for patients with aggressive pituitary tumors.
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Affiliation(s)
- Brandon A Miller
- Department of Neurosurgery, Emory University, Atlanta, GA 30322, USA.
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10
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Role of peroxisome proliferator-activated receptor gamma and its ligands in the treatment of hematological malignancies. PPAR Res 2011; 2008:834612. [PMID: 18528522 PMCID: PMC2408681 DOI: 10.1155/2008/834612] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Accepted: 04/21/2008] [Indexed: 02/07/2023] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a multifunctional transcription factor with important regulatory roles in inflammation, cellular growth, differentiation, and apoptosis. PPARgamma is expressed in a variety of immune cells as well as in numerous leukemias and lymphomas. Here, we review recent studies that provide new insights into the mechanisms by which PPARgamma ligands influence hematological malignant cell growth, differentiation, and survival. Understanding the diverse properties of PPARgamma ligands is crucial for the development of new therapeutic approaches for hematological malignancies.
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11
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Occhi G, Losa M, Albiger N, Trivellin G, Regazzo D, Scanarini M, Monteserin-Garcia JL, Fröhlich B, Ferasin S, Terreni MR, Fassina A, Vitiello L, Stalla G, Mantero F, Scaroni C. The glucose-dependent insulinotropic polypeptide receptor is overexpressed amongst GNAS1 mutation-negative somatotropinomas and drives growth hormone (GH)-promoter activity in GH3 cells. J Neuroendocrinol 2011; 23:641-9. [PMID: 21554434 DOI: 10.1111/j.1365-2826.2011.02155.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Somatic mutations in the GNAS1 gene, encoding the α-subunit of the heterotrimeric stimulatory G protein (Gαs), occur in approximately 40% of growth hormone (GH)-secreting pituitary tumours. By altering the adenylate cyclase-cAMP-protein kinase A pathway, they unequivocally give somatotroph cells a growth advantage. Hence, the pathogenesis of somatotropinomas could be linked to anomalies in receptors coupled to the cAMP second-messenger cascade. Among them, the glucose-dependent insulinotropic polypeptide receptor (GIPR) is already known to play a primary role in the impaired cAMP-dependent cortisol secretion in patients affected by food-dependent Cushing's syndrome. In the present study, 43 somatotropinomas and 12 normal pituitary glands were investigated for GIPR expression by quantitative reverse transcriptase-polymerase chain reaction, western blotting and immunohistochemistry. Tumoural specimens were also evaluated for GNAS1 mutational status. The effect of GIPR overexpression on cAMP levels and GH transcription was evaluated in an in vitro model of somatotropinomas, the GH-secreting pituitary cell line GH3. GIPR was expressed at higher levels compared to normal pituitaries in 13 GNAS1 mutation-negative somatotropinomas. GIP stimulated adenylyl cyclase and GH-promoter activity in GIPR-transfected GH3 cells, confirming a correct coupling of GIPR to Gαs. In a proportion of acromegalic patients, GIPR overexpression appeared to be associated with a paradoxical increase in GH after an oral glucose tolerance test. Whether GIPR overexpression in acromegalic patients may be associated with this paradoxical response or more generally involved in the pathogenesis of acromegaly, as suggested by the mutually exclusive high GIPR levels and GNAS1 mutations, remains an open question.
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Affiliation(s)
- G Occhi
- Endocrinology Division, Department of Medical and Surgical Sciences, Hospital/University of Padova, Padova, Italy.
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12
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Bogazzi F, Rossi G, Lombardi M, Raggi F, Urbani C, Sardella C, Cosci C, Martino E. Effect of rosiglitazone on serum IGF-I concentrations in uncontrolled acromegalic patients under conventional medical therapy: results from a pilot phase 2 study. J Endocrinol Invest 2011; 34:e43-51. [PMID: 20671417 DOI: 10.1007/bf03347060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Current therapies for acromegaly are unsatisfactory for some patients. High-dose thiazolidinediones have been reported to reduce serum GH levels in animal models of acromegaly. The objective of the study was to evaluate the effect of increasing doses of rosiglitazone on serum GH and IGF-I concentrations in acromegalic patients. DESIGN Phase 2 clinical trial. PATIENTS AND METHODS Five consecutive patients with active and uncontrolled acromegaly under conventional medical therapies were treated with increasing doses of rosiglitazone [4 mg/day every month, starting from 8 up to 20 mg/day] added to previous medical therapies for acromegaly. RESULTS Mean serum IGF-I concentrations decreased from 547 ± 91 to 265 ± 126 μg/l (p<0,001) during rosiglitazone treatment: 4 patients had normal serum IGF-I concentrations, and a patient had lowered serum IGF-I values, although still abnormal, at the end of the study. On the contrary, serum GH concentrations did not significantly changed during rosiglitazone therapy as well as other pituitary hormones. No relevant side effects of rosiglitazone were observed during the study period. Quantitative real time PCR and Western blotting showed that rosiglitazone lowered GH-dependent hepatic generation of IGF-I in HepG2 cell line. CONCLUSIONS Rosiglitazone reduces serum IGF-I concentrations in patients with uncontrolled acromegaly under conventional medical therapies, likely acting on the GH-dependent hepatic synthesis of IGF-I. Large studies are necessary to confirm the role of rosiglitazone as an adjunctive therapy for uncontrolled acromegalic patients under conventional medical therapies.
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Affiliation(s)
- F Bogazzi
- Department of Endocrinology and Metabolism, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy.
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The multiple endocrine neoplasia type 1 (MEN1) tumor suppressor regulates peroxisome proliferator-activated receptor gamma-dependent adipocyte differentiation. Mol Cell Biol 2009; 29:5060-9. [PMID: 19596783 DOI: 10.1128/mcb.01001-08] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Menin, the product of the MEN1 (multiple endocrine neoplasia type 1) tumor suppressor gene, is involved in activation of gene transcription as part of an MLL1 (mixed-lineage leukemia 1)/MLL2 (KMT2A/B)-containing protein complex which harbors methyltransferase activity for lysine 4 of histone H3 (H3K4). As MEN1 patients frequently develop lipomas and peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed in several MEN1-related tumor types, we investigated regulation of PPARgamma activity by menin. We found that menin is required for adipocyte differentiation of murine 3T3-L1 cells and PPARgamma-expressing mouse embryonic fibroblasts. Menin augments PPARgamma target gene expression through recruitment of H3K4 methyltransferase activity. Menin interacts directly with the activation function 2 transcription activation domain of PPARgamma in a ligand-independent fashion. Ligand-dependent coactivation, however, is dependent on the LXXLL motif of menin and the intact helix 12 of PPARgamma. We propose that menin is an important factor in PPARgamma-mediated adipogenesis and that loss of PPARgamma function may contribute to lipoma development in MEN1 patients.
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Bibliography. Current world literature. Diabetes and the endocrine pancreas II. Curr Opin Endocrinol Diabetes Obes 2008; 15:383-93. [PMID: 18594281 DOI: 10.1097/med.0b013e32830c6b8e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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