Familial isolated pituitary adenoma (FIPA) occurs in families and is unrelated to multiple endocrine neoplasia type 1 and Carney complex. Mutations in AIP account only for 15–25% of FIPA families. CDKN1B mutations cause MEN4 in which affected patients can suffer from pituitary adenomas. With this study, we wanted to assess whether mutations in CDKN1B occur among a large cohort of AIP mutation-negative FIPA kindreds. Eighty-eight AIP mutation-negative FIPA families were studied and 124 affected subjects underwent sequencing of CDKN1B. Functional analysis of putative CDKN1B mutations was performed using in silico and in vitro approaches. Germline CDKN1B analysis revealed two nucleotide changes: c.286A>C (p.K96Q) and c.356T>C (p.I119T). In vitro, the K96Q change decreased p27 affinity for Grb2 but did not segregate with pituitary adenoma in the FIPA kindred. The I119T substitution occurred in a female patient with acromegaly. p27I119T shows an abnormal migration pattern by SDS–PAGE. Three variants (p.S56T, p.T142T, and c.605+36C>T) are likely nonpathogenic because In vitro effects were not seen. In conclusion, two patients had germline sequence changes in CDKN1B, which led to functional alterations in the encoded p27 proteins in vitro. Such rare CDKN1B variants may contribute to the development of pituitary adenomas, but their low incidence and lack of clear segregation with affected patients make CDKN1B sequencing unlikely to be of use in routine genetic investigation of FIPA kindreds. However, further characterization of the role of CDKN1B in pituitary tumorigenesis in these and other cases could help clarify the clinicopathological profile of MEN4.
Maria A Tichomirowa, Misu Lee, Anne Barlier, Adrian F Daly, Ilaria Marinoni, Marie-Lise Jaffrain-Rea, Luciana A Naves, Patrice Rodien, Vincent Rohmer, Fabio Rueda Faucz, Philippe Caron, Bruno Estour, Pierre Lecomte, Françoise Borson-Chazot, Alfred Penfornis, Maria Yaneva, Mirtha Guitelman, Emily Castermans, Catherine Verhaege, Jean-Louis Wémeau, Antoine Tabarin, Carmen Fajardo Montañana, Brigitte Delemer, Veronique Kerlan, Jean-Louis Sadoul, Christine Cortet Rudelli, Françoise Archambeaud, Sabine Zacharieva, Marily Theodoropoulou, Thierry Brue, Alain Enjalbert, Vincent Bours, Natalia S Pellegata, and Albert Beckers
Adrian F Daly, Bo Yuan, Frederic Fina, Jean-Hubert Caberg, Giampaolo Trivellin, Liliya Rostomyan, Wouter W de Herder, Luciana A Naves, Daniel Metzger, Thomas Cuny, Wolfgang Rabl, Nalini Shah, Marie-Lise Jaffrain-Rea, Maria Chiara Zatelli, Fabio R Faucz, Emilie Castermans, Isabelle Nanni-Metellus, Maya Lodish, Ammar Muhammad, Leonor Palmeira, Iulia Potorac, Giovanna Mantovani, Sebastian J Neggers, Marc Klein, Anne Barlier, Pengfei Liu, L’Houcine Ouafik, Vincent Bours, James R Lupski, Constantine A Stratakis, and Albert Beckers
Somatic mosaicism has been implicated as a causative mechanism in a number of genetic and genomic disorders. X-linked acrogigantism (XLAG) syndrome is a recently characterized genomic form of pediatric gigantism due to aggressive pituitary tumors that is caused by submicroscopic chromosome Xq26.3 duplications that include GPR101. We studied XLAG syndrome patients (n = 18) to determine if somatic mosaicism contributed to the genomic pathophysiology. Eighteen subjects with XLAG syndrome caused by Xq26.3 duplications were identified using high-definition array comparative genomic hybridization (HD-aCGH). We noted that males with XLAG had a decreased log2 ratio (LR) compared with expected values, suggesting potential mosaicism, whereas females showed no such decrease. Compared with familial male XLAG cases, sporadic males had more marked evidence for mosaicism, with levels of Xq26.3 duplication between 16.1 and 53.8%. These characteristics were replicated using a novel, personalized breakpoint junction-specific quantification droplet digital polymerase chain reaction (ddPCR) technique. Using a separate ddPCR technique, we studied the feasibility of identifying XLAG syndrome cases in a distinct patient population of 64 unrelated subjects with acromegaly/gigantism, and identified one female gigantism patient who had had increased copy number variation (CNV) threshold for GPR101 that was subsequently diagnosed as having XLAG syndrome on HD-aCGH. Employing a combination of HD-aCGH and novel ddPCR approaches, we have demonstrated, for the first time, that XLAG syndrome can be caused by variable degrees of somatic mosaicism for duplications at chromosome Xq26.3. Somatic mosaicism was shown to occur in sporadic males but not in females with XLAG syndrome, although the clinical characteristics of the disease were similarly severe in both sexes.
Massimo Terzolo, Giuseppe Reimondo, Paola Berchialla, Emanuele Ferrante, Elena Malchiodi, Laura De Marinis, Rosario Pivonello, Silvia Grottoli, Marco Losa, Salvatore Cannavo, Diego Ferone, Marcella Montini, Marta Bondanelli, Ernesto De Menis, Chiara Martini, Efisio Puxeddu, Antonino Velardo, Alessandro Peri, Marco Faustini-Fustini, Patrizia Tita, Francesca Pigliaru, Giulia Peraga, Giorgio Borretta, Carla Scaroni, Nicoletta Bazzoni, Antonio Bianchi, Alessandro Berton, Andreea Liliana Serban, Roberto Baldelli, Letizia Maria Fatti, Annamaria Colao, Maura Arosio, and for the Italian Study Group of Acromegaly
It is debated if acromegalic patients have an increased risk to develop malignancies. The aim of the present study was to assess the standardized incidence ratios (SIRs) of different types of cancer in acromegaly on a large series of acromegalic patients managed in the somatostatin analogs era. It was evaluated the incidence of cancer in an Italian nationwide multicenter cohort study of 1512 acromegalic patients, 624 men and 888 women, mean age at diagnosis 45 ± 13 years, followed up for a mean of 10 years (12573 person-years) in respect to the general Italian population. Cancer was diagnosed in 124 patients, 72 women and 52 men. The SIRs for all cancers was significantly increased compared to the general Italian population (expected: 88, SIR 1.41; 95% CI, 1.18–1.68, P < 0.001). In the whole series, we found a significantly increased incidence of colorectal cancer (SIR 1.67; 95% CI, 1.07–2.58, P = 0.022), kidney cancer (SIR 2.87; 95% CI, 1.55–5.34, P < 0.001) and thyroid cancer (SIR 3.99; 95% CI, 2.32–6.87, P < 0.001). The exclusion of 11 cancers occurring before diagnosis of acromegaly (all in women) did not change remarkably the study outcome. In multivariate analysis, the factors significantly associated with an increased risk of malignancy were age and family history of cancer, with a non-significant trend for the estimated duration of acromegaly before diagnosis. In conclusion, we found evidence that acromegaly in Italy is associated with a moderate increase in cancer risk.
Annamaria Colao, Carolina Di Somma, Rosario Pivonello, Antongiulio Faggiano, Gaetano Lombardi, and Silvia Savastano
Surgery is the first-line treatment of patients with clinically non-functioning pituitary adenomas (NFAs). Because of lack of clinical syndrome these tumours are diagnosed with a variable delay, when patients suffer from compression symptoms (hypopituitarism, headache and visual field defects) due to the extension of the tumour outside the pituitary fossa. Surgery is followed by residual tumour tissue in most patients. In these cases, radiotherapy is generally used to prevent tumour regrowth. However, NFA cell membranes, in analogy with GH- and PRL-secreting adenomas, express somatostatin and dopamine receptors. Treatment with somatostatin analogues (SSA) and dopamine agonists (DA) induced some beneficial effects on visual field defects and was also followed by tumour shrinkage in a minority of cases. DA seem to be more effective on tumour shrinkage than SSA. More recently, a combination treatment with both SSA and DA have been tested in a few patients with interesting results. Lack of randomized, placebo-controlled trials prevents any conclusion on the efficacy of these drugs. By contrast, use of gonatotrophin-releasing hormone analogues has been abandoned.
Manel Puig-Domingo, Joan Gil, Miguel Sampedro-Nuñez, Mireia Jordà, Susan M Webb, Guillermo Serra, Laura Pons, Isabel Salinas, Alberto Blanco, Montserrat Marques-Pamies, Elena Valassi, Antonio Picó, Araceli García-Martínez, Cristina Carrato, Raquel Buj, Carlos del Pozo, Gabriel Obiols, Carles Villabona, Rosa Cámara, Carmen Fajardo-Montañana, Clara V Alvarez, Ignacio Bernabéu, and Mónica Marazuela
Pharmacologic treatment of acromegaly is currently based upon assay-error strategy, the first-generation somatostatin receptor ligands (SRL) being the first-line treatment. However, about 50% of patients do not respond adequately to SRL. Our objective was to evaluate the potential usefulness of different molecular markers as predictors of response to SRL. We used somatotropinoma tissue obtained after surgery from a national cohort of 100 acromegalic patients. Seventy-one patients were treated with SRL during at least 6 months under maximal therapeutic doses according to IGF1 values. We analyzed the expression of SSTR2, SSTR5, AIP, CDH1 (E-cadherin), MKI67 (Ki-67), KLK10, DRD2, ARRB1, GHRL, In1-Ghrelin, PLAGL1 and PEBP1 (RKIP) by RT-qPCR and mutations in GNAS gene by Sanger sequencing. The response to SRL was categorized as complete response (CR), partial (PR) or non-response (NR) if IGF1 was normal, between >2<3 SDS or >3 SDS IGF1 at 6 months of follow-up, respectively. From the 71 patients treated, there were 27 CR (38%), 18 PR (25%) and 26 NR (37%). SSTR2, Ki-67 and E-cadherin were associated with SRL response (P < 0.03, P < 0.01 and P < 0.003, respectively). E-cadherin was the best discriminator for response prediction (AUC = 0.74, P < 0.02, PPV of 83.7%, NPV of 72.6%), which was validated at protein level. SSTR5 expression was higher in patients pre-treated with SRL before surgery. We conclude that somatotropinomas showed heterogeneity in the expression of genes associated with SRL response. E-cadherin was the best molecular predictor of response to SRL. Thus, the inclusion of E-cadherin in subsequent treatment-decision after surgical failure may be useful in acromegaly.
Iulia Potorac, Patrick Petrossians, Adrian F Daly, Franck Schillo, Claude Ben Slama, Sonia Nagi, Mouna Sahnoun, Thierry Brue, Nadine Girard, Philippe Chanson, Ghaidaa Nasser, Philippe Caron, Fabrice Bonneville, Gérald Raverot, Véronique Lapras, François Cotton, Brigitte Delemer, Brigitte Higel, Anne Boulin, Stéphan Gaillard, Florina Luca, Bernard Goichot, Jean-Louis Dietemann, Albert Beckers, and Jean-François Bonneville
Responses of GH-secreting adenomas to multimodal management of acromegaly vary widely between patients. Understanding the behavioral patterns of GH-secreting adenomas by identifying factors predictive of their evolution is a research priority. The aim of this study was to clarify the relationship between the T2-weighted adenoma signal on diagnostic magnetic resonance imaging (MRI) in acromegaly and clinical and biological features at diagnosis. An international, multicenter, retrospective analysis was performed using a large population of 297 acromegalic patients recently diagnosed with available diagnostic MRI evaluations. The study was conducted at ten endocrine tertiary referral centers. Clinical and biochemical characteristics, and MRI signal findings were evaluated. T2-hypointense adenomas represented 52.9% of the series, were smaller than their T2-hyperintense and isointense counterparts (P<0.0001), were associated with higher IGF1 levels (P=0.0001), invaded the cavernous sinus less frequently (P=0.0002), and rarely caused optic chiasm compression (P<0.0001). Acromegalic men tended to be younger at diagnosis than women (P=0.067) and presented higher IGF1 values (P=0.01). Although in total, adenomas had a predominantly inferior extension in 45.8% of cases, in men this was more frequent (P<0.0001), whereas in women optic chiasm compression of macroadenomas occurred more often (P=0.0067). Most adenomas (45.1%) measured between 11 and 20 mm in maximal diameter and bigger adenomas were diagnosed at younger ages (P=0.0001). The T2-weighted signal differentiates GH-secreting adenomas into subgroups with particular behaviors. This raises the question of whether the T2-weighted signal could represent a factor in the classification of acromegalic patients in future studies.
Adrian F Daly, Philippe A Lysy, Céline Desfilles, Liliya Rostomyan, Amira Mohamed, Jean-Hubert Caberg, Veronique Raverot, Emilie Castermans, Etienne Marbaix, Dominique Maiter, Chloe Brunelle, Giampaolo Trivellin, Constantine A Stratakis, Vincent Bours, Christian Raftopoulos, Veronique Beauloye, Anne Barlier, and Albert Beckers
X-linked acrogigantism (X-LAG) syndrome is a newly described form of inheritable pituitary gigantism that begins in early childhood and is usually associated with markedly elevated GH and prolactin secretion by mixed pituitary adenomas/hyperplasia. Microduplications on chromosome Xq26.3 including the GPR101 gene cause X-LAG syndrome. In individual cases random GHRH levels have been elevated. We performed a series of hormonal profiles in a young female sporadic X-LAG syndrome patient and subsequently undertook in vitro studies of primary pituitary tumor culture following neurosurgical resection. The patient demonstrated consistently elevated circulating GHRH levels throughout preoperative testing, which was accompanied by marked GH and prolactin hypersecretion; GH demonstrated a paradoxical increase following TRH administration. In vitro, the pituitary cells showed baseline GH and prolactin release that was further stimulated by GHRH administration. Co-incubation with GHRH and the GHRH receptor antagonist, acetyl-(d-Arg2)-GHRH (1-29) amide, blocked the GHRH-induced GH stimulation; the GHRH receptor antagonist alone significantly reduced GH release. Pasireotide, but not octreotide, inhibited GH secretion. A ghrelin receptor agonist and an inverse agonist led to modest, statistically significant increases and decreases in GH secretion, respectively. GHRH hypersecretion can accompany the pituitary abnormalities seen in X-LAG syndrome. These data suggest that the pathology of X-LAG syndrome may include hypothalamic dysregulation of GHRH secretion, which is in keeping with localization of GPR101 in the hypothalamus. Therapeutic blockade of GHRH secretion could represent a way to target the marked hormonal hypersecretion and overgrowth that characterizes X-LAG syndrome.
E Ferrante, C Pellegrini, S Bondioni, E Peverelli, M Locatelli, P Gelmini, P Luciani, A Peri, G Mantovani, S Bosari, P Beck-Peccoz, A Spada, and A Lania
Somatostatin analogs currently used in the treatment of acromegaly and other neuroendocrine tumors inhibit hormone secretion and cell proliferation by binding to somatostatin receptor type (SST) 2 and 5. The antiproliferative pathways coupled to these receptors have been only partially characterized. The aim of this study was to evaluate the effect of octreotide and super selective SST2 (BIM23120) and SST5 (BIM23206) analogs on apoptotic activity and apoptotic gene expression in human somatotroph tumor cells. Eight somatotroph tumors expressing similar levels of SST2 and SST5 evaluated by real-time PCR and western blot analyses were included in the study. In cultured cells obtained from these tumors, octreotide induced a dose-dependent increase of caspase-3 activity (160 ± 20% vs basal at 10 nM) and cleaved cytokeratin 18 levels (172 ± 25% vs basal) at concentrations higher than 0.1 nM. This effect was due to SST2 activation since BIM23120 elicited comparable responses, while BIM23206 was ineffective. BIM23120-stimulated apoptosis was dependent on phosphatases, since it was abrogated by the inhibitor orthovanadate, and independent from the induction of apoptosis-related genes, such as p53, p63, p73, Bcl-2, Bax, BID, BIK, TNFSF8, and FADD. In somatotroph tumors, both BIM23120 and BIM2306 caused growth arrest as indicated by the increase in p27 and decrease in cyclin D1 expression. In conclusion, the present study showed that octreotide-induced apoptosis in human somatotroph tumor cells by activating SST2. This effect, together with the cytostatic action exerted by both SST2 and SST5 analogs, might account for the tumor shrinkage observed in acromegalic patients treated with long-acting somatostatin analogs.
María Andrea Camilletti, Alejandra Abeledo-Machado, Pablo A Perez, Erika Y Faraoni, Fernanda De Fino, Susana B Rulli, Jimena Ferraris, Daniel Pisera, Silvina Gutierrez, Peter Thomas, and Graciela Díaz-Torga
Membrane progesterone receptors are known to mediate rapid nongenomic progesterone effects in different cell types. Recent evidence revealed that mPRα is highly expressed in the rat pituitary, being primarily localized in lactotrophs, acting as an intermediary of P4-inhibitory actions on prolactin secretion. The role of mPRs in prolactinoma development remains unclear. We hypothesize that mPR agonists represent a novel tool for hyperprolactinemia treatment. To this end, pituitary expression of mPRs was studied in three animal models of prolactinoma. Expression of mPRs and nuclear receptor was significantly decreased in tumoral pituitaries compared to normal ones. However, the relative proportion of mPRα and mPRβ was highly increased in prolactinomas. Interestingly, the selective mPR agonist (Org OD 02-0) significantly inhibited PRL release in both normal and tumoral pituitary explants, displaying a more pronounced effect in tumoral tissues. As P4 also regulates PRL secretion indirectly, by acting on dopaminergic neurons, we studied mPR involvement in this effect. We found that the hypothalamus has a high expression of mPRs. Interestingly, both P4 and OrgOD 02-0 increased dopamine release in hypothalamus explants. Moreover, in an in vivo treatment, that allows both, pituitary and hypothalamus actions, the mPR agonist strongly reduced the hyperprolactinemia in transgenic females carrying prolactinoma. Finally, we also found and interesting gender difference: males express higher levels of pituitary mPRα/β, a sex that does not develop prolactinoma in these mice models. Taken together, these findings suggest mPRs activation could represent a novel tool for hyperprolactinemic patients, especially those that present resistance to dopaminergic drugs.
A Raitila, M Georgitsi, A Karhu, K Tuppurainen, M J Mäkinen, K Birkenkamp-Demtröder, K Salmenkivi, T F Ørntoft, J Arola, V Launonen, P Vahteristo, and L A Aaltonen
Germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene were recently observed in patients with pituitary adenoma predisposition (PAP). Though AIP mutation-positive individuals with prolactin-, mixed growth hormone/prolactin-, and ACTH-producing pituitary adenomas as well as non-secreting pituitary adenomas have been reported, most mutation-positive patients have had growth hormone-producing adenomas diagnosed at relatively young age. Pituitary adenomas are also component tumors of some familial endocrine neoplasia syndromes such as multiple endocrine neoplasia type 1 (MEN1) and Carney complex (CNC). Genes underlying MEN1 and CNC are rarely mutated in sporadic pituitary adenomas, but more often in other lesions contributing to these two syndromes. Thus far, the occurrence of somatic AIP mutations has not been studied in endocrine tumors other than pituitary adenomas. Here, we have analyzed 32 pituitary adenomas and 79 other tumors of the endocrine system for somatic AIP mutations by direct sequencing. No somatic mutations were identified. However, two out of nine patients with prolactin-producing adenoma were shown to harbor a Finnish founder mutation (Q14X) with a complete loss of the wild-type allele in the tumors. These results are in agreement with previous studies in that prolactin-producing adenomas are component tumors in PAP. The data also support the previous finding that somatic AIP mutations are not common in pituitary adenomas and suggest that such mutations are rare in other endocrine tumors as well.