Showing papers by "Anna Spada published in 2012"
TL;DR: C19MC cluster aberrations are a characteristic of Ca with respect to Ad and evidences point towards a role for 19q13.4 miRNA clusters as oncogenes in parathyroid tumourigenesis.
Abstract: A subset of over-expressed microRNAs (miRNAs) identified in parathyroid carcinomas (Ca) compared to normal glands belongs to C19MC, a cluster on chromosome 19q13.4 involved in stem cell biology and tumourigenesis. In this study, the expression of C19MC-MIR371-3 clusters and the molecular mechanisms presiding their modulation were investigated in a series of six normal parathyroids, 24 adenomas (Ad), 15 Ca and five matched metastases. The general expression levels of C19MC or MIR371-3 clusters in Ad lesions did not differ from normal glands, while they distinguished Ad from Ca at unsupervised hierarchical cluster analysis (P=0.0008). MIR517C showed the most significant difference in expression between Ca and Ad (P=0.0003) and it positively correlated with serum calcium, parathormone and tumour weight. In regard to the molecular mechanism determining C19MC cluster activation, we could detect C19MC copy number (CN) gain in ten Ca (67%) extending distal to the MIR371-3 cluster in almost all samples. Conversely, only four Ad (16%) showed C19MC amplification, with one case presenting distal genomic aberration to MIR371-3. Globally, CN variations of 19q13.4 loci were significantly associated with MIR517C up-regulation (P=0.006). Opposite to normal glands where C19MC promoter was methylated, hypomethylation occurred in 15 out of 30 analysed tumours. Though the epigenetic status did not correlate with C19MC miRNA expression levels, loss of C19MC promoter methylation was significantly associated with Ca and metastatic disease (P=0.01). In conclusion, C19MC cluster aberrations are a characteristic of Ca with respect to Ad. Altogether, these evidences point towards a role for 19q13.4 miRNA clusters as oncogenes in parathyroid tumourigenesis.
87 citations
TL;DR: CDC73 mutations and negative immunostaining were common in atypical adenomas, but no local recurrence was observed in any case with successful surgical removal after follow-up periods of 27 to 210 months.
Abstract: Objective
To determine if molecular and immunohistochemical (IHC) features of the HRPT2/CDC73 gene and its product, parafibromin, predict the natural history of parathyroid malignancy, particularly atypical adenoma, as seen in a single-centre patient cohort.
65 citations
TL;DR: It is indicated that FLNA is crucial for D2R expression and signaling in lactotrophs, suggesting that the impaired response to DA may be related to the reduction of FLNA expression in DA-resistant prolactinomas.
Abstract: Context: Dopamine agonists (DA) are the first choice treatment of prolactinomas. However, a subset of patients is resistant to DA, due to undefined dopamine D2 receptor (D2R) alterations. Recently, D2R was found to associate with filamin-A (FLNA), a widely expressed cytoskeleton protein with scaffolding properties, in melanoma and neuronal cells. Objective: The aim of the study was to investigate the role of FLNA in D2R expression and signaling in human tumorous lactotrophs and rat MMQ and GH3 cells. Design: We analyzed FLNA expression in a series of prolactinomas by immunohistochemistry and Western blotting. We performed FLNA silencing or transfection experiments in cultured cells from DA-sensitive or -resistant prolactinomas and in MMQ and GH3 cells, followed by analysis of D2R expression and signaling. Results: We demonstrated reduced FLNA and D2R expression in DA-resistant tumors. The crucial role of FLNA on D2R was demonstrated by experiments showing that: 1) FLNA silencing in DA-sensitive prolactino...
53 citations
TL;DR: Although long-term safety and efficacy data are required, cinacalcet might be considered a treatment option in MEN1 patients who have contraindications to surgery or persistent PHPT after surgery.
Abstract: Objective: Primary hyperparathyroidism (PHPT) is a challenging problem in type 1 multiple endocrine neoplasia (MEN1) due to the high postsurgery recurrence rate. The aim was to evaluate the efficacy of cinacalcet in MEN1 patients in comparison with patients with sporadic PHPT (sPHPT) and the effect of Arg990Gly calcium-sensing receptor (CASR) polymorphism on the response to treatment. Design: This is a randomized, crossover, double-blind study carried out in the University Hospitals. Methods: Fifteen MEN1 patients with PHPT were randomized to two groups, one administered with 30 mg daily cinacalcet, titrated until calcium normalization, and one with placebo. After 3 months, patients were reassessed and after washout switched to the other treatment. For comparison, 20 sPHPT patients with similar calcium levels were administered with cinacalcet for 3 months. Ionized and total calcium, phosphate, and parathyroid hormone (PTH) were evaluated. CASR Arg990Gly was genotyped on blood DNA by direct sequencing. Results: Cinacalcet normalized calcium, increased phosphate, and reduced PTH levels in all patients. Cinacalcet dosage required to normalize calcium in MEN1 and sPHPT was not significantly different (45G21 vs 54G25 mg/day). Few mild adverse events, not requiring drug withdrawal, were observed in both the groups. No association between Arg990Gly CASR polymorphism and response to cinacalcet was found. Conclusions: This short-term prospective study demonstrated that the efficacy profile of cinacalcet in patients with MEN1-related PHPT and in those with sPHPT was similar and was not influenced by the 990 CASR variant. Although long-term safety and efficacy data are required, cinacalcet might be considered a treatment option in MEN1 patients who have contraindications to surgeryor persistent PHPT after surgery.
41 citations
TL;DR: This study did not confirm a better response of d3GHR to PEG-V treatment in acromegaly and other studies are needed to determine whether deviation from Hardy-Weinberg equilibrium may indicate an association of d2GHR genotype with poor response to usual treatments.
Abstract: Context: The influence of full-length GH receptor (GHR) and exon 3-deleted GHR (d3GHR) on responsiveness to pegvisomant (PEG-V) in acromegalic patients is uncertain. Objective: The aim of the study was to assess the distribution of GHR genotypes in a large series of patients on PEG-V therapy and their influence on treatment efficacy and adverse effects. Design and Setting: A cross-sectional multicenter pharmacogenetic study was conducted in 16 Italian endocrinology centers of major universities and tertiary care hospitals. Patients: The study included 127 acromegalic patients enrolled from 2009 to 2010 not cured by previous surgery, radiotherapy, and long-acting somatostatin (SST) analogs, treated with PEG-V. Intervention and Main Outcome Measure: Sixty-three of 127 patients received combined PEG-V + SST analog therapy. Clinical and hormonal data at diagnosis and before and during PEG-V therapy were inserted in a database. GHR exon 3 deletion and other polymorphisms were genotyped by the coordinator cente...
37 citations
TL;DR: The latest findings on the molecular basis underlying these defects suggest the existence of a clinical and genetic/epigenetic overlap between PHP-Ia andPHP-Ib, and highlight the necessity of a new clinical classification of these disorders based on molecular findings.
Abstract: Pseudohypoparathyroidism-Ia and -Ib (PHP-Ia and -Ib) are caused by mutations in GNAS exons 1-13 and methylation defects in the imprinted GNAS cluster, respectively. PHP-Ia patients show Albright hereditary osteodystrophy (AHO), together with resistance to the action of different hormones that activate the Gs-coupled pathway. In PHP-Ib patients AHO is classically absent and hormone resistance is limited to PTH and TSH. This disorder is caused by GNAS methylation alterations with loss of imprinting at the exon A/B differentially methylated region (DMR) being the most consistent and recurrent defect. The familial form of the disease (AD-PHP-Ib) is typically associated with an isolated loss of imprinting at the exon A/B DMR due to microdeletions disrupting the upstream STX16 gene. In addition, deletions removing the entire NESP55 DMR, located within GNAS, associated with loss of all the maternal GNAS imprints have been identified in some AD-PHP-Ib kindreds. Conversely, most sporadic PHP-Ib cases have GNAS imprinting abnormalities that involve multiple DMRs, but the genetic lesion underlying these defects is unknown. Recently, methylation defects have been detected in a subset of patients with PHP-Ia and variable degrees of AHO, indicating a molecular overlap between the 2 forms. Imprinting defects do not seem to be associated with the severity of AHO neither with specific AHO signs. In conclusion, the latest findings on the molecular basis underlying these defects suggest the existence of a clinical and genetic/epigenetic overlap between PHP-Ia and PHP-Ib, and highlight the necessity of a new clinical classification of these disorders based on molecular findings.
37 citations
TL;DR: In GHD acromegalic patients, GH therapy improved body composition, lipid profile, and quality of life as in patients with GHD due to nonfunctioning pituitary adenoma, without negative effects on glucose metabolism.
Abstract: Objective: Effects of GH replacement in patients with GH deficiency (GHD) after a cure for acromegaly so far have been poorly studied, although its prevalence among acromegalic patients may reach the 60%. The aim of the study was to evaluate whether metabolic parameters and quality of life are improved by GH replacement in patients with prior acromegaly and severe GHD. Design and Methods: This was a prospective study on 42 GHD subjects [22 men, mean age (sd): 48 ± 10]: 10 acromegalics treated with recombinant human GH (group A), 12 acromegalics who refused treatment (group B), and 20 subjects operated for nonfunctioning pituitary adenoma on recombinant human GH (group C). Serum IGF-I levels, lipid profile, glucose levels (fasting and after an oral glucose tolerance test), glycosylated hemoglobin, insulin resistance (homeostasis model assessment insulin resistance index), anthropometric parameters (body mass index, waist circumference, body composition), and quality of life (Questions on Life Satisfaction-...
25 citations
TL;DR: Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders with a prevalence of 21/1000 in women between 55 and 75 years of age, corresponding to a 3/1000 prevalence in the general population.
Abstract: Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders with a prevalence of 21/1000 in women between 55 and 75 years of age, corresponding to a 3/1000 prevalence in the general population [1]. Sporadic (non-familial) PHPT accounts for 90–95% of all cases. While activation of the protooncogene cyclin D1 (CCDN1) and inactivation of the tumor suppressor menin gene (MEN1) contribute to parathyroid adenomatosis, and inactivation of the parafibromin gene (CDC73) contributes to parathyroid carcinogenesis, the molecular pathogenesis of these tumors is incompletely understood. Dysregulated Wnt signaling and activation of b-catenin is involved in several cancers and consequently there has been recent interest in whether this is implicated in parathyroid tumorigenesis. In the absence of Wnt, cytosolic b-catenin phosphorylation catalyzed by glycogen synthase kinase (GSK)-b on serine/threonine residues (S33, S37, T41) encoded by exon 3 of the CTNNB1 gene leads to the ubiquitination and to degradation mediated by the proteasome. Mutation of the serine/threonine residues causes stabilization of the b-catenin protein and localization to the nucleus where it activates gene transcription. Several studies have been reported examining CTNNB1 gene mutations and aberrant b-catenin localization in sporadic parathyroid adenomas. While studies from Sweden found the homozygous S37A mutation in *7% of 124 parathyroid adenomas and aberrant b-catenin localization in all cases [2, 3], other studies from Japan [4, 5], USA [6],
20 citations
TL;DR: The phenotype associated with this structural rearrangement, which substantially reduces the synthesis of Wolframin, confirms a tissue-specific pattern of expression of WFS1, suggests the presence of a different protein dosage sensitivity in different tissues and could be causative of DI and OA in this patient.
18 citations
TL;DR: SSDCT is not a reliable tool to identify HPAI, but it appears to be more useful in confirming the normality of HPA function if ITT is contraindicated, and retesting patients by SDCT is useful before starting an unnecessary replacement therapy.
Abstract: OBJEcTIVE: The diagnosis of hypothalamic-pituitary-adrenal insufficiency (HPAI) is a major clinical challenge. The gold standard procedure remains insulin tolerance test (ITT). This study aimed to evaluate the usefulness of standard-dose corticotrophin stimulation test (sDcT) in diagnosing HPAI. DEsIGN: In this prospective study we performed sDcT and ITT in 55 consecutive patients (37F/18M) affected by pituitary disorders. rEsULTs: A normal response to ITT was found in 44 patients, while HPAI was diagnosed in 11. Using ITT as reference test, the rOc curve showed that a cortisol value of 18 µg/dl (500 nmol/L) at 30 min or 21.8 µg/dl (600 nmol/L) at 60 min after sDcT represents the best compromise between sensitivity and specificity in diagnosing HPAI. Moreover, 30 min cortisol values >20.3 µg/dl (560 nmol/L) or 60 min cortisol values >24.1 µg/dl (665 nmol/L) exclude HPAI. Four out of 15 patients of Group A, previously non-respondent to showed a normal response to a second sDcT. cONcLUsIONs: sDcT is not a reliable tool to identify HPAI, but it appears to be more useful in confirming the normality of HPA function. When sDcT fails to exclude HPAI, ITT should be performed. If ITT is contraindicated, retesting patients by sDcT is useful before starting an unnecessary replacement therapy.
16 citations
TL;DR: The role of cAMP in the control of cell proliferation in selected cell types and in particular in somatotroph cells has been further confirmed by identification of genetics defect affecting the regulatory subunit IA of PKA.
Abstract: The pituitary is the target of different neurohormones that have a crucial role in the control of cell differentiation, cell proliferation and hormone secretion by recognizing specific receptors belonging to the G Protein-Coupled Receptor super-family (GPCR). Evidence from in vitro studies and naturally occurring human diseases indicate that several endocrine cells, and particularly somatotrophs, recognize cAMP as a growth factor. Accordingly, mutations of the alpha subunit of the stimulatory G protein gene (GNAS) leading to the constitutive activation of adenylyl cyclase (i.e. gsp oncogene) have been recognized in a significant proportion of GH-secreting pituitary adenomas. The role of cAMP in the control of cell proliferation in selected cell types and in particular in somatotroph cells has been further confirmed by identification of genetics defect affecting the regulatory subunit IA of PKA. The role of cAMP in the control of cell proliferation as well as the crosstalk with different intracellular signalling pathways will be discussed.