[show abstract][hide abstract] ABSTRACT: Context: Inactivating germline mutations of the probable tumor suppressor gene Armadillo Repeat Containing 5 (ARMC5) have recently been identified as a genetic cause of macronodular adrenal hyperplasia (MAH). Objective: We searched for ARMC5 mutations in a large cohort of patients with MAH. The clinical phenotype of patients with and without ARMC5 mutations was compared. Methods: Blood DNA from 34 MAH patients was genotyped using Sanger sequencing. Diurnal serum cortisol measurements, plasma ACTH levels, urinary steroids, 6-day Liddle's test, adrenal computed tomography, and weight of adrenal glands at adrenalectomy were assessed. Results: Germline ARMC5 mutations were found in 15 out of 34 patients (44.1%). In silico analysis of the mutations indicated that 7 (20.6%) predicted major implications for gene function. Late-night cortisol levels were higher in patients with ARMC5 damaging mutations compared to those without and/or with non-pathogenic mutations (14.5±5.6 vs. 6.7±4.3, p<0.001). All patients carrying a pathogenic ARMC5 mutation had clinical Cushing's syndrome (7/7, 100%) compared to 14/27 (52%) of those without or with mutations that were predicted to be benign (p=0.029). Repeated measures analysis showed overall higher urinary 17-hydroxycorticosteroids and serum cortisol values in the patients with ARMC5 damaging mutations during the 6 day Liddle's test (p=0.0002). Conclusions: ARMC5 mutations are implicated in clinically severe Cushing's syndrome associated with MAH. Knowledge of a patient's ARMC5 status has important clinical implications for the diagnosis of Cushing's syndrome and genetic counseling of patients and their families.
The Journal of clinical endocrinology and metabolism 03/2014; · 6.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: Objective
Silent corticotroph adenomas (SCAs) present as non-functional pituitary tumours in routine preoperative evaluation. The objective of this study was to evaluate the diagnostic accuracy of MRI T2-weighted sequences for detecting the corticotroph subtype preoperatively. DesignThe preoperative T2-weighted MRI sequences were retrospectively evaluated in patients with SCA and two control groups: clinically manifest corticotroph macroadenomas (CSMs) and, non-functional gonadotroph macroadenomas (NFGMs). All were selected from a registry of 1,096 patients in whom transsphenoidal surgery was performed in the same tertiary reference centre. T2-weighted MRI sequences were independently classified by one senior endocrinologist and one senior radiologist who were blinded to the clinical and histological features. Patients17 patients with SCA, 14 with CSM and 60 with NFGM MeasurementsPituitary MRI including T2-weighted sequences. Two aspects were retained: multiple microcysts (MMs) and the absence of microcysts. Hormonal data included plasma prolactin, IGF-1, testosterone or oestradiol, LH, FT4, TSH, morning plasma cortisol and an ACTH-stimulation test, when available. ResultsMMs were present in 76% (13/17) of SCAs, 21% (3/14) of CSMs and 5% (3/60) of NFGMs. The presence of MMs in clinically non-functioning macroadenomas had a sensitivity of 76% and a specificity of 95% for predicting SCA. Conclusion
The presence of MMs in T2-weighted MRI is a good diagnostic tool to suggest the corticotroph subtype in an apparently non-functional pituitary tumour.This article is protected by copyright. All rights reserved.
[show abstract][hide abstract] ABSTRACT: Background Corticotropin-independent Cushing's syndrome is caused by tumors or hyperplasia of the adrenal cortex. The molecular pathogenesis of cortisol-producing adrenal adenomas is not well understood. Methods We performed exome sequencing of tumor-tissue specimens from 10 patients with cortisol-producing adrenal adenomas and evaluated recurrent mutations in candidate genes in an additional 171 patients with adrenocortical tumors. We also performed genomewide copy-number analysis in 35 patients with cortisol-secreting bilateral adrenal hyperplasias. We studied the effects of these genetic defects both clinically and in vitro. Results Exome sequencing revealed somatic mutations in PRKACA, which encodes the catalytic subunit of cyclic AMP-dependent protein kinase (protein kinase A [PKA]), in 8 of 10 adenomas (c.617A→C in 7 and c.595_596insCAC in 1). Overall, PRKACA somatic mutations were identified in 22 of 59 unilateral adenomas (37%) from patients with overt Cushing's syndrome; these mutations were not detectable in 40 patients with subclinical hypercortisolism or in 82 patients with other adrenal tumors. Among 35 patients with cortisol-producing hyperplasias, 5 (including 2 first-degree relatives) carried a germline copy-number gain (duplication) of the genomic region on chromosome 19 that includes PRKACA. In vitro studies showed impaired inhibition of both PKA catalytic subunit mutants by the PKA regulatory subunit, whereas cells from patients with germline chromosomal gains showed increased protein levels of the PKA catalytic subunit; in both instances, basal PKA activity was increased. Conclusions Genetic alterations of the catalytic subunit of PKA were found to be associated with human disease. Germline duplications of this gene resulted in bilateral adrenal hyperplasias, whereas somatic PRKACA mutations resulted in unilateral cortisol-producing adrenal adenomas. (Funded by the European Commission Seventh Framework Program and others.).
New England Journal of Medicine 02/2014; · 51.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pan-genomic analyses of genetic and epigenetic alterations and gene expression profiles are providing important new insights into the pathogenesis and molecular classification of cancers. The technologies and methods used for these studies are rapidly diversifying and improving. The use of such methodologies for the analysis of adrenocortical tumours has revealed clear transcriptomic (mRNA and microRNA expression profiles), epigenomic (DNA methylation profiles) and genomic (DNA mutations and chromosomal alterations) differences between benign and malignant tumours. Interestingly, genomic studies of adrenal cancers have also identified subtypes of malignant tumours, which demonstrate distinct patterns of molecular alterations and are associated with different clinical outcomes. These discoveries have created the opportunity for classifying adrenocortical tumours on the basis of molecular analyses. Following these genomic studies, efforts to develop new molecular tools that improve diagnosis and prognostication of patients with adrenocortical tumours have also been made. This Review describes the progress that has been made towards classification of adrenocortical tumours to date based on key genomic approaches. In addition, the potential for the development and use of various molecular tools to personalize the management of patients with adrenocortical tumours is discussed.
[show abstract][hide abstract] ABSTRACT: Background: The use of ketoconazole has been recently questioned after warnings from the European Medicine Agencies and the Food and Drug Administration due to potential hepatotoxicity. However, ketoconazole is frequently used as a drug to lower circulating cortisol levels. Several pharmacological agents have recently been approved for the treatment of Cushing's disease (CD) despite limited efficacy and significant side effects. Ketoconazole has been used worldwide for more than 30 years in CD but in the absence of large scale study, its efficacy and tolerance are still under debate. Patients and methods: We conducted a French retrospective, multicenter study reviewing data from patients treated by ketoconazole as a single agent for CD, with the aim of clarifying efficacy and tolerance in order to better determine the benefits/risk balance. Results: Data from 200 patients were included in this study. At the last follow-up, 49.3% of patients had normal urinary free cortisol (UFC) levels, 25.6% had at least a 50% decrease, and 25.4% had unchanged UFC levels. The median final dose of ketoconazole was 600 mg/day. Forty patients (20%) received ketoconazole as a pre-surgical treatment; 40-50% of these patients showed improvement of hypertension, hypokalemia and diabetes, and 48.7% had normal UFC before surgery. Overall, 41 patients (20.5%) stopped the treatment due to poor tolerance. Mild (< 5N) and major (>5N) increases in liver enzymes were observed in 13.5 % and 2.5% of patients respectively. No fatal hepatitis was observed. Conclusions: Ketoconazole is an effective drug with acceptable side effects. It should be used under close liver enzyme monitoring. Hepatotoxicity is usually mild and resolutive after drug withdrawal.
The Journal of clinical endocrinology and metabolism 01/2014; · 6.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: adrenocortical carcinoma (ACC) is a rare disease with a poor overall outcome. Transcriptome analysis identified two groups of ACCs with different prognosis. In aggressive ACCs, somatic mutations of the tumor suppressor gene TP53 and the proto-oncogene β-catenin are detected in 50% of cases. For the remaining aggressive ACCs and for the group with a better prognosis, molecular alterations are unknown.
to identify new molecular actors driving adrenal tumorigenesis.
analysis by mass-array of 374 mutations among 32 common oncogenes or tumor suppressor genes was performed on the tumoral DNA of 26 ACCs, using Sequenom® OncoCarta™ Panels.
four mutations were identified, two previously known β-catenin mutations and one alteration in two other genes: Janus Kinase 3 (JAK3) and retinoblastoma gene (RB1). The JAK3 alteration was found in leukocyte DNA and therefore considered as a polymorphism and not a somatic event. The full RB1 tumor suppressor gene was subsequently sequenced in a cohort of 49 ACCs (26 ACCs from the "OncoCarta cohort" and 23 other ACCs): three somatic mutations were identified, all in the poor outcome ACC group. By immunohistochemistry, a loss of the retinoblastoma protein (pRb) was found exclusively in aggressive ACCs in 27% of cases (7 out of 26), three of them with an inactivating RB1 mutation. Among the seven pRb negative ACCs, five had an allele loss at the RB1 locus.
parallel analysis of somatic mutations among known cancer genes allowed us to identify RB1 as a new actor in aggressive ACCs. These results suggest a prognostic significance of pRb expression loss in ACCs.
European Journal of Endocrinology 12/2013; · 3.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Background Corticotropin-independent macronodular adrenal hyperplasia may be an incidental finding or it may be identified during evaluation for Cushing's syndrome. Reports of familial cases and the involvement of both adrenal glands suggest a genetic origin of this condition. Methods We genotyped blood and tumor DNA obtained from 33 patients with corticotropin-independent macronodular adrenal hyperplasia (12 men and 21 women who were 30 to 73 years of age), using single-nucleotide polymorphism arrays, microsatellite markers, and whole-genome and Sanger sequencing. The effects of armadillo repeat containing 5 (ARMC5) inactivation and overexpression were tested in cell-culture models. Results The most frequent somatic chromosome alteration was loss of heterozygosity at 16p (in 8 of 33 patients for whom data were available [24%]). The most frequent mutation identified by means of whole-genome sequencing was in ARMC5, located at 16p11.2. ARMC5 mutations were detected in tumors obtained from 18 of 33 patients (55%). In all cases, both alleles of ARMC5 carried mutations: one germline and the other somatic. In 4 patients with a germline ARMC5 mutation, different nodules from the affected adrenals harbored different secondary ARMC5 alterations. Transcriptome-based classification of corticotropin-independent macronodular adrenal hyperplasia indicated that ARMC5 mutations influenced gene expression, since all cases with mutations clustered together. ARMC5 inactivation decreased steroidogenesis in vitro, and its overexpression altered cell survival. Conclusions Some cases of corticotropin-independent macronodular adrenal hyperplasia appear to be genetic, most often with inactivating mutations of ARMC5, a putative tumor-suppressor gene. Genetic testing for this condition, which often has a long and insidious prediagnostic course, might result in earlier identification and better management. (Funded by Agence Nationale de la Recherche and others.).
New England Journal of Medicine 11/2013; 369(22):2105-2114. · 51.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Background Bilateral macronodular adrenal hyperplasia is a rare cause of primary adrenal Cushing's syndrome. In this form of hyperplasia, hypersecretion of cortisol suppresses the release of corticotropin by pituitary corticotrophs, which results in low plasma corticotropin levels. Thus, the disease has been termed corticotropin-independent macronodular adrenal hyperplasia. We examined the abnormal production of corticotropin in these hyperplastic adrenal glands. Methods We obtained specimens of hyperplastic macronodular adrenal tissue from 30 patients with primary adrenal disease. The corticotropin precursor proopiomelanocortin and corticotropin expression were assessed by means of a polymerase-chain-reaction assay and immunohistochemical analysis. The production of corticotropin and cortisol was assessed in 11 specimens with the use of incubated explants and cell cultures coupled with hormone assays. Corticotropin levels were measured in adrenal and peripheral venous blood samples from 2 patients. Results The expression of proopiomelanocortin messenger RNA (mRNA) was detected in all samples of hyperplastic adrenal tissue. Corticotropin was detected in steroidogenic cells arranged in clusters that were disseminated throughout the adrenal specimens. Adrenal corticotropin levels were higher in adrenal venous blood samples than in peripheral venous samples, a finding that was consistent with local production of the peptide within the hyperplastic adrenals. The release of adrenal corticotropin was stimulated by ligands of aberrant membrane receptors but not by corticotropin-releasing hormone or dexamethasone. A semiquantitative score for corticotropin immunostaining in the samples correlated with basal plasma cortisol levels. Corticotropin-receptor antagonists significantly inhibited in vitro cortisol secretion. Conclusions Cortisol secretion by the adrenals in patients with macronodular hyperplasia and Cushing's syndrome appears to be regulated by corticotropin, which is produced by a subpopulation of steroidogenic cells in the hyperplastic adrenals. Thus, the hypercortisolism associated with bilateral macronodular adrenal hyperplasia appears to be corticotropin-dependent. (Funded by the Agence Nationale de la Recherche and others.).
New England Journal of Medicine 11/2013; 369(22):2115-2125. · 51.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: One of the key messages of recent Salpea and Stratakis work is to underline the clinical similarities shared by these syndromes that could be explained by a defect in the same signaling pathway, i.e. activation of the cAMP pathway. That being said, we would like to emphasize that hepatopancreato-biliary lesions are one additional feature shared both by Carney complex and McCune Albright syndrome.
Molecular and Cellular Endocrinology 10/2013; · 4.04 Impact Factor
[show abstract][hide abstract] ABSTRACT: Point mutations of the PRKAR1A gene are a genetic cause of Carney complex (CNC) and primary pigmented nodular adrenocortical disease (PPNAD), but in 30% of the patients no mutation is detected.
Set up a routine-based technique for systematic detection of large deletions or duplications of this gene and functionally characterize these mutations.
Multiplex Ligation-dependent Probe Amplification (MLPA) of the 12 exons of the PRKAR1A gene was validated and used to detect large rearrangements in 13 typical CNC and 39 confirmed or putative PPNAD without any mutations of the gene. An in-frame deletion, was characterized by Western blot and BRET technique for its interaction with the catalytic subunit.
MLPA allowed identification of exon 3-6 deletion in three patients of a family with typical CNC. The truncated protein is expressed, but rapidly degraded, and does not interact with the protein kinase A catalytic subunit.
MLPA is a powerful technique that may be used following the lack of mutations detected by direct sequencing in patients with bona fide CNC or PPNAD. We report here one such new deletion, as an example. However, these gene defects are not a frequent cause of CNC or PPNAD.
European Journal of Endocrinology 10/2013; · 3.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Carney complex (CNC) is a hereditary disease associating cardiac myxoma, spotty skin pigmentation and endocrine overactivity. CNC is caused by inactivating mutations in the PRKAR1A gene encoding PKA type I alpha regulatory subunit (RIα). Although PKA activity is enhanced in CNC, the mechanisms linking PKA dysregulation to endocrine tumorigenesis are poorly understood. In this study, we used FRET-based sensors for cAMP and PKA activity to define the role of RIα in the spatiotemporal organization of the cAMP/PKA pathway. RIα knockdown in HEK293 cells increased basal as well as forskolin or prostaglandin E1 (PGE1)-stimulated total cellular PKA activity as reported by western blots of endogenous PKA targets and the FRET-based global PKA activity reporter, AKAR3. Using variants of AKAR3 targeted to subcellular compartments, we identified similar increases in the response to PGE1 in the cytoplasm and at the outer mitochondrial membrane. In contrast, at the plasma membrane, the response to PGE1 was decreased along with an increase in basal FRET ratio. These results were confirmed by western blot analysis of basal and PGE1-induced phosphorylation of membrane-associated vasodilator-stimulated phosphoprotein. Similar differences were observed between the cytoplasm and the plasma membrane in human adrenal cells carrying a RIα inactivating mutation. RIα inactivation also increased cAMP in the cytoplasm, at the outer mitochondrial membrane and at the plasma membrane, as reported by targeted versions of the cAMP indicator Epac1-camps. These results show that RIα inactivation leads to multiple, compartment-specific alterations of the cAMP/PKA pathway revealing new aspects of signaling dysregulation in tumorigenesis.
Human Molecular Genetics 10/2013; · 7.69 Impact Factor
[show abstract][hide abstract] ABSTRACT: Primary aldosteronism is the main cause of secondary hypertension, resulting from adrenal aldosterone producing adenomas (APA) or bilateral hyperplasia. Here we show that constitutive activation of WNT/β-catenin signalling is the most frequent molecular alteration found in 70% of APA. We provide evidence that decreased expression of the WNT inhibitor SFRP2 may be contributing to deregulated WNT signalling and APA development in patients. This is supported by the demonstration that mice with genetic ablation of Sfrp2 have increased aldosterone production and ectopic differentiation of zona glomerulosa cells. We further show that β-catenin plays an essential role in the control of basal and Angiotensin II-induced aldosterone secretion, by activating AT1R, CYP21 and CYP11B2 transcription. This relies on both LEF/TCF-dependent activation of AT1R and CYP21 regulatory regions and indirect activation of CYP21 and CYP11B2 promoters, through increased expression of the nuclear receptors NURR1 and NUR77. Altogether these data show that aberrant WNT/β-catenin activation is associated with APA development and suggest that WNT pathway may be a good therapeutic target in primary aldosteronism.
Human Molecular Genetics 10/2013; · 7.69 Impact Factor
[show abstract][hide abstract] ABSTRACT: Context:Adrenocortical cancer (ACC) is a rare cancer with poor prognosis and scant treatment options. In ACC, no personalized approach has emerged but no extensive molecular screening has been performed to date.Objective:The objective of the study was to evaluate the presence of a large number of potentially targetable molecular events in a large cohort of advanced ACC.Design, Setting, and Participants:We used hot spot gene sequencing (Ion Torrent, 40 patients) and comparative genomic hybridization (CGH; 28 patients; a subset of the entire cohort) in adult stage III-IV ACC samples to screen for mutations and copy number abnormalities of potential interest for therapeutic use in 46 and 130 genes, respectively.Results:At least one copy number alteration or mutation was found in 19 patients (47.5%). The most frequent mutations were detected on TP53, ATM, and CTNNB1 [6 of 40 (15%), 5 of 40 (12.5%), and 4 of 40 (10%), respectively]. The most frequent copy number alterations identified were: amplification of the CDK4 oncogene (5 of 28; 17.9%) and deletion of the CDKN2A (4 of 28; 14.3%) and CDKN2B (3 of 28; 10.7%) tumor suppressor genes. Amplifications of FGFR1, FGF9, or FRS2 were discovered in three subjects (10.7%). Associated alterations were: deletions of CDKN2A, CDKN2B with ATM mutations, and TP53 mutations with CTNNB1 mutations.Conclusions:No simple targetable molecular event emerged. Drugs targeting the cell cycle could be the most relevant new therapeutic approach for patients with advanced ACC. Inhibitors of the fibroblast growth factor receptor pathway could also be a therapeutic option in a subset of patients, whereas other targeted therapies should be considered on a case-by-case basis.
The Journal of clinical endocrinology and metabolism 08/2013; · 6.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: In a previous 15-day, Phase II study of patients with de novo or persistent/recurrent Cushing's disease (core study), treatment with pasireotide 600 μg sc bid reduced urinary free cortisol (UFC) levels in 76 % of patients and normalized UFC in 17 %. The objective of this study was to evaluate the efficacy and safety of extended treatment with pasireotide. This was a planned, open-ended, single-arm, multicenter extension study (primary endpoint: 6 months). Patients aged ≥18 years with Cushing's disease who completed the core study could enter the extension if they achieved UFC normalization at core study end and/or obtained significant clinical benefit. Of the 38 patients who completed the core study, 19 entered the extension and 18 were included in the efficacy analyses (three responders, 11 reducers, four non-reducers in the core study). At data cut-off, median treatment duration in the extension was 9.7 months (range: 2 months to 4.8 years). At extension month 6, 56 % of the 18 patients had lower UFC than at core baseline and 22 % had normalized UFC. Of the four patients who remained on study drug at month 24, one had normalized UFC. Reductions in serum cortisol, plasma adrenocorticotropic hormone, body weight and diastolic blood pressure were observed. The most common adverse events were mild-to-moderate gastrointestinal disorders and hyperglycemia. Pasireotide offers a tumor-directed medical therapy that may be effective for the extended treatment of some patients with Cushing's disease.
[show abstract][hide abstract] ABSTRACT: Background: Wnt/β-catenin signaling pathway activation plays an important role in adrenocortical tumorigenesis, but is only in part related to β-catenin activating somatic mutations. Recently, genetic alteration in AXIN2, a key component of the Wnt/β-catenin signaling pathway, has been described in adrenocortical tumors and specifically in adrenocortical carcinoma (ACC). Aim: To assess frequency and consequences of AXIN genes alteration on a large cohort of ACCs. Patients and methods: 49 adult sporadic ACCs, with expression data available, in addition to both ACC cell lines H295 and H295R were studied. AXIN2 exon 8 hotspot sequencing was performed on the entire cohort. AXIN1 entire coding region was studied on the 8 ACCs with nuclear β-catenin staining. Results: The previously described AXIN2 in-frame heterozygous 12bp deletion c2013_2024del12 was found in 1 of the 49 ACC studied (2%), in a tumor with pSer45del activating CTNNB1 mutation and nuclear β-catenin staining. This heterozygous deletion was also found in the patient's germline DNA, extracted from peripheral blood leukocytes. This genetic alteration was also present in H295 and H295R cell lines. The single-nucleotide polymorphism rs35415678 was found with an allele frequency similar to those found in reference populations. No correlation between AXIN2 expression, AXIN2 genetic variant or nuclear β-catenin staining was observed. No AXIN1 alterations were found in the 8 ACCs studied. Conclusions: AXIN genes do not play a major role in ACC tumorigenesis and Wnt/β- catenin signaling pathway activation. AXIN2 germline variant c2013_2024del12 is likely to be a non-pathogenic polymorphism.
Journal of endocrinological investigation 07/2013; · 1.65 Impact Factor
[show abstract][hide abstract] ABSTRACT: Adrenocortical carcinoma (ACC) is a rare cancer with poor prognosis. Local and distant recurrences occur in a subset of tumors classified as 'aggressive' ACC (aACC), as opposed to 'non-aggressive' ACC (naACC). In this study, we investigated whether tissue and serum microRNAs (miRNAs) are predictive of ACC prognosis. Tissue miRNA expression profiles were determined using microarrays in a test series of 6 adrenocortical adenomas (ACA), 6 naACC and 6 aACC. Eight miRNAs were selected for further validation by quantitative RT-PCR (10 ACA, 9 naACC, 9 aACC, and 3 normal adrenals). Serum levels of five miRNAs were measured in samples from 56 subjects (19 healthy controls, 14 ACA, 9 naACC and 14 aACC patients). MiR-195 and miR-335 levels were significantly decreased in both tumor and serum samples of ACC patients relative to ACA patients or healthy controls. MiR-139-5p and miR-376a levels were significantly increased in aACC compared to naACC patients in tumor samples only. Tissue miR-483-5p was markedly up-regulated in a majority of ACC as compared to ACA or healthy controls but most importantly, serum miR-483-5p was detected only in aACC patients. High circulating levels of miR-483-5p or low circulating levels of miR-195 were associated with both shorter recurrence-free survival (p=0.0004 and p=0.0014, respectively) and shorter overall survival (p=0.0005 and p=0.0086, respectively). In conclusion, the present study reports for the first time that circulating miR-483-5p and miR-195 are promising non-invasive biomarkers with a highly specific prognostic value for the clinical outcome of ACC patients.
Endocrine Related Cancer 06/2013; · 5.26 Impact Factor
[show abstract][hide abstract] ABSTRACT: Paragangliomas are neuroendocrine tumors frequently associated with mutations in RET, NF1, VHL, and succinate dehydrogenase (SDHx) genes. Methylome analysis of a large paraganglioma cohort identified three stable clusters, associated with distinct clinical features and mutational status. SDHx-related tumors displayed a hypermethylator phenotype, associated with downregulation of key genes involved in neuroendocrine differentiation. Succinate accumulation in SDH-deficient mouse chromaffin cells led to DNA hypermethylation by inhibition of 2-OG-dependent histone and DNA demethylases and established a migratory phenotype reversed by decitabine treatment. Epigenetic silencing was particularly severe in SDHB-mutated tumors, potentially explaining their malignancy. Finally, inactivating FH mutations were identified in the only hypermethylated tumor without SDHx mutations. These findings emphasize the interplay between the Krebs cycle, epigenomic changes, and cancer.
[show abstract][hide abstract] ABSTRACT: Transcription factor SOX10 plays a role in the maintenance of progenitor cell multipotency, lineage specification, and cell differentiation and is a major actor in the development of the neural crest. It has been implicated in Waardenburg syndrome (WS), a rare disorder characterized by the association between pigmentation abnormalities and deafness, but SOX10 mutations cause a variable phenotype that spreads over the initial limits of the syndrome definition. On the basis of recent findings of olfactory-bulb agenesis in WS individuals, we suspected SOX10 was also involved in Kallmann syndrome (KS). KS is defined by the association between anosmia and hypogonadotropic hypogonadism due to incomplete migration of neuroendocrine gonadotropin-releasing hormone (GnRH) cells along the olfactory, vomeronasal, and terminal nerves. Mutations in any of the nine genes identified to date account for only 30% of the KS cases. KS can be either isolated or associated with a variety of other symptoms, including deafness. This study reports SOX10 loss-of-function mutations in approximately one-third of KS individuals with deafness, indicating a substantial involvement in this clinical condition. Study of SOX10-null mutant mice revealed a developmental role of SOX10 in a subpopulation of glial cells called olfactory ensheathing cells. These mice indeed showed an almost complete absence of these cells along the olfactory nerve pathway, as well as defasciculation and misrouting of the nerve fibers, impaired migration of GnRH cells, and disorganization of the olfactory nerve layer of the olfactory bulbs.
The American Journal of Human Genetics 05/2013; 92(5):707-24. · 11.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: Context:The cortisol secretion of adrenocortical adenomas can be either subtle or overt. The mechanisms leading to the autonomous hypersecretion of cortisol are unknown.Objective:To identify the gene expression profile associated with the autonomous and excessive cortisol secretion of adrenocortical adenomas.Patients and Methods:The transcriptome of 22 unilateral adrenocortical adenomas (5 non-secreting, 6 subclinical cortisol producing, 11 cortisol producing) was studied and correlated with cortisol secretion. Phosphodiesterase 8B (PDE8B) expression was measured by Western Blot.ResultsUnsupervised clustering identified two groups of adenomas with a difference in secretion level (p=0.008). Cluster 1 included only cortisol producing adenomas (8 out of 11), while Cluster 2 was an admixture of the non-secreting, the subclinical cortisol-secreting and 3 of the 11 cortisol-secreting adenomas (Fisher exact p=0.002). This cluster was driven by genes related to cortisol secretion and to extracellular matrix.More than three thousand genes correlated with cortisol secretion. Among the positively correlated were the steroidogenic enzymes, genes involved in cholesterol metabolism and glutathione S-transferases. Among the negatively correlated genes were genes related to transcripts translation and the transcription factor GATA-6.The PDE8B, which inactivates the PKA pathway, unexpectedly showed the strongest positive correlation with cortisol secretion, confirmed by Western Blot. The PKA-activity/cAMP ratio was increased in adenomas with high PDE8B levels, suggesting counter-regulation to limit downstream activation of the pathway.Conclusion:The transcriptome of adrenocortical adenomas reveals a major association with cortisol secretion and identifies specific groups of genes implicated in steroid secretion, suggesting that cAMP signalling alterations might be frequent in cortisol secreting adenomas.
The Journal of clinical endocrinology and metabolism 03/2013; · 6.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: Adrenocortical carcinoma (ACC) is a rare and highly aggressive endocrine neoplasm, with limited therapeutic options. Activating β-catenin somatic mutations are found in ACC and have been associated with a poor clinical outcome. In fact, activation of the Wnt/β-catenin signaling pathway seems to play a major role in ACC aggressiveness, and might, thus, represent a promising therapeutic target.
Similar to patient tumor specimen the H295 cell line derived from an ACC harbors a natural activating β-catenin mutation. We herein assess the in vitro and in vivo effect of β-catenin inactivation using a doxycyclin (dox) inducible shRNA plasmid in H295R adrenocortical cancer cells line (clone named shβ).
Following dox treatment a profound reduction in β-catenin expression was detectable in shβ clones in comparison to control clones (Ctr). Accordingly, we observed a decrease in Wnt/βcatenin-dependent luciferase reporter activity as well as a decreased expression of AXIN2 representing an endogenous β-catenin target gene. Concomitantly, β-catenin silencing resulted in a decreased cell proliferation, cell cycle alterations with cell accumulation in the G1 phase and increased apoptosis in vitro. In vivo, on established tumor xenografts in athymic nude mice, 9 days of β-catenin silencing resulted in a significant reduction of CTNNB1 and AXIN2 expression. Moreover, continous β-catenin silencing, starting 3 days after tumor cell inoculation, was associated with a complete absence of tumor growth in the shβ group while tumors were present in all animals of the control group.
In summary, these experiments provide evidences that Wnt/β-catenin pathway inhibition in ACC is a promising therapeutic target.
PLoS ONE 01/2013; 8(2):e55743. · 3.73 Impact Factor