Epigenetic control of adamantinomatous craniopharyngiomas

INTRODUCTION

Studies addressing the methylation pattern in adamantinomatous craniopharyngioma (ACP) are lacking.

OBJECTIVE

To identify methylation signatures in ACPs regarding clinical presentation and outcome.

METHODS

Clinical and pathology data were collected from 35 ACP patients (54% male; 18.1 years [2-68]). CTNNB1 mutations and methylation profile (MethylationEPIC/Array-Illumina) were analyzed in tumoral DNA. Unsupervised machine learning analysis of this comprehensive methylome sample was achieved using hierarchical clustering and multi-dimensional scaling. Statistical associations between clusters and clinical features were achieved using Fisher's test and global biological process interpretations were aided by Gene Ontology enrichment analyses.

RESULTS

Two clusters were revealed consistently by all unsupervised methods (ACP-1: n = 18; ACP-2: n = 17) with strong bootstrap statistical support. ACP-2 was enriched by CTNNB1 mutations (100% vs 56%, P = 0.0006), hypomethylated in CpG Island (CGI), non-CGI sites, and globally (P < 0.001), and associated with greater tumor size (24.1 vs 9.5cm3, P = 0.04). Enrichment analysis highlighted pathways on signaling transduction, transmembrane receptor, development of anatomical structures, cell-adhesion, cytoskeleton organization, and cytokine binding, and also cell-type specific biological processes as regulation of oligodendrocytes, keratinocyte, and epithelial cells differentiation.

CONCLUSION

Two clusters of ACP patients were consistently revealed by unsupervised machine learning methods, being one of them significantly hypomethylated, enriched by CTNNB1 mutated ACPs, and associated with increased tumor size. Enrichment analysis reinforced pathways involved in tumor proliferation and in cell-specific tumoral microenvironment.

The molecular pathogenesis of craniopharyngiomas

Research from the last 20 years has provided important insights into the molecular pathogenesis of craniopharyngiomas (CPs). Besides the well-known clinical and histological differences between the subtypes of CPs, adamantinomatous (ACP) and papillary (PCP) craniopharyngiomas, other molecular differences have been identified, further elucidating pathways related to the origin and development of such tumors. The present minireview assesses current knowledge on embryogenesis and the genetic, epigenetic, transcriptomic, and signaling pathways involved in the ACP and PCP subtypes, revealing the similarities and differences in their profiles. ACP and PCP subtypes can be identified by the presence of mutations in CTNNB1 and BRAF genes, with prevalence around 60% and 90%, respectively. Therefore, β-catenin accumulates in the nucleus-cytoplasm of cell clusters in ACPs and, in PCPs, cell immunostaining with specific antibody against the V600E-mutated protein can be seen. Distinct patterns of DNA methylation further differentiate ACPs and PCPs. In addition, research on genetic and epigenetic changes and tumor microenvironment specificities have further clarified the development and progression of the disease. No relevant transcriptional differences in ACPs have emerged between children and adults. In conclusion, ACPs and PCPs present diverse genetic signatures and each subtype is associated with specific signaling pathways. A better understanding of the pathways related to the growth of such tumors is paramount for the development of novel targeted therapeutic agents.

Integrating methylome and transcriptome signatures expands the molecular classification of the pituitary tumors

PURPOSE

To explore pituitary tumors by methylome and transcriptome signatures in a heterogeneous ethnic population.

DESIGN

Retrospective cross-sectional study.

PATIENTS AND METHODS

Clinicopathological features, methylome and transcriptome were evaluated in pituitary tumors from 77 patients (61% women, age: 12-72 years) followed due to functioning (FPT: GH-secreting n = 18, ACTH-secreting n = 14) and non-functioning pituitary tumors (NFPT, n = 45) at Ribeirao Preto Medical School, University of Sao Paulo.

RESULTS

Unsupervised hierarchical clustering analysis (UHCA) of methylome (n = 77) and transcriptome (n = 65 out of 77) revealed three clusters each: one enriched by FPT, other by NFPT, and another by ACTH-secreting and NFPT. Comparison between each omics-derived clusters identified 3,568 and 5,994 differentially methylated and expressed genes, respectively, which were associated with each other, with tumor clinical presentation, and with 2017 and 2022 WHO classifications. UHCA considering 11 transcripts related to pituitary development/differentiation also supported three clusters: POU1F1-driven somatotroph, TBX19-driven corticotroph, and NR5A1-driven gonadotroph adenomas, with rare exceptions (NR5A1 expressed in few GH-secreting and corticotroph-silent adenomas; POU1F1 in few ACTH-secreting adenomas; and TBX19 in few NFPTs).

CONCLUSIONS

This large heterogenic ethnic Brazilian cohort confirms that integrated methylome and transcriptome signatures classify FPT and NFPT, which are associated with clinical presentation and tumor invasiveness. Moreover, the cluster NFPT/ACTH-secreting adenomas raises interest regarding tumor heterogeneity, supporting the challenge raised by the 2017 and 2022 WHO definition regarding the discrepancy, in rare cases, between clinical presentation and pituitary lineage markers. Finally, making our data publicly available enables further studies to validate genes/pathways involved in pituitary tumor pathogenesis and prognosis.

ODP354 Telomeres Length and Wnt/beta-catenin Pathway in Adamantinomatous Craniopharyngiomas

Objectives

To evaluate how telomeres length behaves in adamantinomtous craniopharyngioma (aCP) and if it contributes to the pathogenesis of aCPs with and without CTNNB1 mutations. Design: Retrospective cross-sectional study enrolling 42 aCPpatients from two tertiary institutions.

Methods

Clinicopathological features were retrieved from patient's charts. Fresh frozen tumors were used for RNA and DNA analyses. Telomere length was evaluated by qPCR (T/S ratio). Somatic mutations in TERT promoter (TERTp) and CTNNB1 were detected by Sanger and/or whole-exome sequencing. We performed RNA-Seq to identify differentially expressed genes in aCPs presenting with shorter or longer telomere lengths.

Results

Mutations in CTNNB1 were detected in 29 (69%) tumors. There was higher frequency of CTNNB1mutations in aCPs from patients diagnosed under the age of 15 years (85% vs 15%; p=0. 04) and a trend to recurrent disease (76% vs 24%; p=0.1). No mutation was detected in the TERTp region. The telomeres were shorter in CTNNB1-mutated aCPs (0.441, IQR: 0.297-0.597 vs 0.607, IQR: 0.445-0.778; p=0. 04) but it was neither associated with clinicopathological features nor with recurrence. RNAseq identified a total of 387 differentially expressed genes, generating two clusters, being one enriched for short telomere and CTNNB1-mutated aCPs.

Conclusions

CTNNB1 mutations are more frequent in children and adolescents and appear to associate with progressive disease. CTNNB1-mutated aCPs have shorter telomeres. This is the first evidence for a relationship between the Wnt/beta-catenin pathway and telomere biology in the pathogenesis of aCPs.

Presentation: No date and time listed

Telomere length and Wnt/β-catenin pathway in adamantinomatous craniopharyngiomas

OBJECTIVES

To evaluate how telomere length behaves in adamantinomtous craniopharyngioma (aCP) and if it contributes to the pathogenesis of aCPs with and without CTNNB1 mutations.

DESIGN

Retrospective cross-sectional study enrolling 42 aCP patients from 2 tertiary institutions.

METHODS

Clinicopathological features were retrieved from the patient's charts. Fresh frozen tumors were used for RNA and DNA analyses. Telomere length was evaluated by qPCR (T/S ratio). Somatic mutations in TERT promoter (TERTp) and CTNNB1 were detected by Sanger and/or whole-exome sequencing. We performed RNA-Seq to identify differentially expressed genes in aCPs presenting with shorter or longer telomere lengths.

RESULTS

Mutations in CTNNB1 were detected in 29 (69%) tumors. There was higher frequency of CTNNB1 mutations in aCPs from patients diagnosed under the age of 15 years (85% vs 15%; P = 0.04) and a trend to recurrent disease (76% vs 24%; P = 0.1). No mutation was detected in the TERTp region. The telomeres were shorter in CTNNB1-mutated aCPs (0.441, IQR: 0.297-0.597vs 0.607, IQR: 0.445-0.778; P = 0.04), but it was neither associated with clinicopathological features nor with recurrence. RNAseq identified a total of 387 differentially expressed genes, generating two clusters, being one enriched for short telomeres and CTNNB1-mutated aCPs.

CONCLUSIONS: CTNNB1

mutations are more frequent in children and adolescents and appear to associate with progressive disease. CTNNB1-mutated aCPs have shorter telomeres, demonstrating a relationship between the Wnt/β-catenin pathway and telomere biology in the pathogenesis of aCPs.

PI3K inhibition by BKM120 results in anti-proliferative effects on corticotroph tumor cells

PURPOSE

Cushing's disease is associated with significant morbidity; thus, additional tumor-directed drugs with the potential to exert antineoplastic effects on corticotroph adenoma cells are desired. The phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) pathway, which plays regulatory role in cell survival and proliferation, is activated in pituitary adenomas. The present study evaluated the effects of BKM120 (Buparlisib), an oral PI3K inhibitor, on cell viability, apoptosis, cell cycle phase distribution, and ACTH production in mouse corticotroph tumor cells.

METHODS

AtT-20/D16v-F2 mouse pituitary corticotroph tumor cells were treated with increasing concentrations of BKM120 or vehicle. Cell viability was measured using an MTS-based assay. Apoptosis was evaluated by Annexin V staining. Cell cycle analysis was performed by propidium iodide DNA staining and flow cytometry. Gene expression of cell cycle regulators (Cdkn1b, Ccnd1, Ccne1, Cdk2, Cdk4, Myc, and Rb1) was assessed by qPCR. Protein expression of p27, total and phosphorylated Akt was assessed by Western blot. ACTH levels were measured in the culture supernatants by chemiluminescent immunometric assay.

RESULTS

Treatment with BKM120 decreased AtT-20/D16v-F2 cell viability, induced a G0/G1 cell cycle arrest, reduced the phosphorylation of Akt at Serine 473, and increased p27 expression. Furthermore, BKM120 treatment diminished ACTH levels in the cell culture supernatants.

CONCLUSION

In vitro inhibition of PI3K/AKT pathway by BKM120 resulted in anti-proliferative effects on corticotroph tumor cells, decreasing cell viability and ACTH production. These encouraging findings shape the path for further experiments with the inhibition of PI3K/AKT pathway in Cushing's disease.

Generalized and tissue specific glucocorticoid resistance

Glucocorticoids (GCs) are steroid hormones that influence several physiologic functions and are among the most frequently prescribed drugs worldwide. Resistance to GCs has been observed in the context of the familial generalized GC resistance (Chrousos' syndrome) or tissue specific GC resistance in chronic inflammatory states. In this review, we have summarized the major factors that influence individual glucocorticoid sensitivity/resistance. The fine-tuning of GC action is determined in a tissue-specific fashion that includes the combination of different GC receptor promoters, translation initiation sites, splice isoforms, interacting proteins, post-translational modifications, and alternative mechanisms of signal transduction.

Clostridium difficile toxins or infection induce upregulation of adenosine receptors and IL-6 with early pro-inflammatory and late anti-inflammatory pattern

Clostridium difficile causes intestinal inflammation, which increases adenosine. We compared the expression of adenosine receptors (AR) subtypes A1, A2A, A2B, and A3 in HCT-8, IEC-6 cells, and isolated intestinal epithelial cells, challenged or not with Clostridium difficile toxin A and B (TcdA and TcdB) or infection (CDI). In HCT-8, TcdB induced an early A2BR expression at 6 h and a late A2AR expression at 6 and 24 h. In addition, both TcdA and TcdB increased IL-6 expression at all time-points (peak at 6 h) and PSB603, an A2BR antagonist, decreased IL-6 expression and production. In isolated cecum epithelial cells, TcdA induced an early expression of A2BR at 2s and 6 h, followed by a late expression of A2AR at 6 and 24 h and of A1R at 24 h. In CDI, A2AR and A2BR expressions were increased at day 3, but not at day 7. ARs play a role in regulating inflammation during CDI by inducing an early pro-inflammatory and a late anti-inflammatory response. The timing of interventions with AR antagonist or agonists may be of relevance in treatment of CDI.

A Brazilian regional basic diet-induced chronic malnutrition drives liver inflammation with higher ApoA-I activity in C57BL6J mice

Malnutrition is still considered endemic in many developing countries. Malnutrition-enteric infections may cause lasting deleterious effects on lipid metabolism, especially in children living in poor settings. The regional basic diet (RBD), produced to mimic the Brazilian northeastern dietary characteristics (rich in carbohydrate and low in protein) has been used in experimental malnutrition models, but few studies have explored the effect of chronic RBD on liver function, a central organ involved in cholesterol metabolism. This study aimed to investigate whether RBD leads to liver inflammatory changes and altered reverse cholesterol metabolism in C57BL6/J mice compared to the control group, receiving a standard chow diet. To evaluate liver inflammation, ionized calcium-binding adapter protein-1 (IBA-1) positive cell counting, interleukin (IL)-1β immunohistochemistry, and tumor necrosis factor (TNF)-α and IL-10 transcription levels were analyzed. In addition, we assessed reverse cholesterol transport by measuring liver apolipoprotein (Apo)E, ApoA-I, and lecithin-cholesterol acyltransferase (LCAT) by RT-PCR. Furthermore, serum alanine aminotransferase (ALT) was measured to assess liver function. RBD markedly impaired body weight gain compared with the control group (P<0.05). Higher hepatic TNF-α (P<0.0001) and IL-10 (P=0.001) mRNA levels were found in RBD-challenged mice, although without detectable non-alcoholic fatty liver disease. Marked IBA-1 immunolabeling and increased number of positive-IBA-1 cells were found in the undernourished group. No statistical difference in serum ALT was found. There was also a significant increase in ApoA mRNA expression in the undernourished group, but not ApoE and LCAT, compared with the control. Altogether our findings suggested that chronic RBD-induced malnutrition leads to liver inflammation with increased ApoA-I activity.

Peripheral clock system circadian abnormalities in Cushing's disease

In Cushing's syndrome, the cortisol rhythm is impaired and can be associated with the disruption in the rhythmic expression of clock genes. In this study, we evaluated the expression of CLOCK, BMAL1, CRY1, CRY2, PER1, PER2, PER3 genes in peripheral blood leukocytes of healthy individuals (n = 13) and Cushing's disease (CD) patients (n = 12). Participants underwent salivary cortisol measurement at 0900 h and 2300 h. Peripheral blood samples were obtained at 0900 h, 1300 h, 1700 h, and 2300 h for assessing clock gene expression by qPCR. Gene expression circadian variations were evaluated by the Cosinor method. In healthy controls, a circadian variation in the expression of CLOCK, BMAL1, CRY1, PER2, and PER3 was observed, whereas the expression of PER1 and CRY2 followed no specific pattern. The expression of PER2 and PER3 in healthy leukocytes presented a late afternoon acrophase, similarly to CLOCK, whereas CRY1 showed night acrophase, similarly to BMAL1. In CD patients, the circadian variation in the expression of clock genes was lost, along with the abolition of cortisol circadian rhythm. However, CRY2 exhibited a circadian variation with acrophase during the dark phase in patients. In conclusion, our data suggest that Cushing's disease, which is characterized by hypercortisolism, is associated with abnormalities in the circadian pattern of clock genes. Higher expression of CRY2 at night outlines its putative role in the cortisol circadian rhythm disruption.

USP8 Mutations and Cell Cycle Regulation in Corticotroph Adenomas

Corticotroph adenomas frequently harbor somatic USP8 mutations. These adenomas also commonly exhibit underexpression of P27, a cell cycle regulator. The present study aimed to determine the influence of USP8 mutations on clinical features of Cushing's disease and to elucidate the relationship between USP8 mutations and P27 underexpression in these tumors. Retrospective study with 32 patients with Cushing's disease was followed at the Ribeirao Preto Medical School University Hospital. We evaluated the patients' clinical data, the USP8 mutation status and the gene expression of cell cycle regulators P27/CDKN1B, CCNE1, CCND1, CDK2, CDK4, and CDK6 in tumor tissue in addition to the protein expression of P27/CDKN1B. We observed somatic mutations in the exon 14 of USP8 in 31.3% of the patients. Larger tumor size was observed in patients harboring USP8 mutations (p=0.04), with similar rates of remission, age of presentation, salivary cortisol at 23:00 h and after 1 mg dexamethasone, ACTH levels, and early postoperative plasma cortisol. We observed no differences regarding the gene or protein expression of the cell cycle regulators according to USP8 mutation status. In this Brazilian series, the observed frequency of USP8 somatic mutations was similar to that reported in European ancestry populations. Although it was reasonable that USP8 mutations could contribute to cell cycle dysregulation and P27 underexpression in corticotroph adenomas, our data did not confirm this hypothesis. It is possible that increased deubiquitinase activity observed in mutated USP8 might influence other pathways related to cell growth and proliferation.

Phenotypic diversity and glucocorticoid sensitivity in patients with familial partial lipodystrophy type 2

Familial partial lipodystrophy type 2 (FPLD2) is characterized by insulin resistance, adipose atrophy of the extremities and central obesity. Due to the resemblance with Cushing's syndrome, we hypothesized a putative role of glucocorticoid in the pathogenesis of metabolic abnormalities in FPLD2.

OBJECTIVE

To evaluate the phenotypic heterogeneity and glucocorticoid sensitivity in FPLD2 patients exhibiting the p.R482W or p.R644C LMNA mutations.

DESIGN, PATIENTS AND MEASUREMENTS

Prospective study with FPLD2 patients (n = 24) and controls (n = 24), who underwent anthropometric, body composition, metabolic profile and adipokines/cytokine plasma measurements. Plasma and salivary cortisol were measured in basal conditions and after 0.25, 0.5 and 1.0 mg of dexamethasone (DEX) given at 23:00 hours. Glucocorticoid receptor (GR) and 11βHSD isoforms expression were assessed by qPCR.

RESULTS

Familial partial lipodystrophy type 2 individuals presented increased waist and neck circumferences, decreased hip circumference, peripheral skinfold thickness and fat mass. Patients presented increased HOMA-IR, triglycerides, TNF-α, IL-1β, IL-6 and IL-10, and decreased adiponectin and leptin plasma levels. FPLD2 patients showed decreased ability to suppress the HPA axis compared with controls after 0.5 mg DEX. The phenotype was more pronounced in patients harbouring the p.R482W LMNA mutation. GRβ overexpression in PBMC was observed in female patients compared with female controls.

CONCLUSIONS

Familial partial lipodystrophy type 2 patients exhibited anthropometric, clinical and biochemical phenotypic heterogeneity related to LMNA mutation sites and to gender. LMNA mutations affecting both lamin A and lamin C lead to more severe phenotype. FPLD2 patients also showed blunted HPA axis response to DEX, probably due to the association of increased levels of proinflammatory cytokines with GRβ overexpression leading to a more severe phenotype in female.

Corrigendum: Transcriptome Analysis Showed a Differential Signature Between Invasive and Non-invasive Corticotrophinomas

[This corrects the article DOI: 10.3389/fendo.2017.00055.].

Impact of the Canonical Wnt Pathway Activation on the Pathogenesis and Prognosis of Adamantinomatous Craniopharyngiomas

CTNNB1 mutations and abnormal β-catenin distribution are associated with the pathogenesis of adamantinomatous craniopharyngioma (aCP). We evaluated the expression of the canonical Wnt pathway components in aCPs and its association with CTNNB1 mutations and tumor progression. Tumor samples from 14 aCP patients and normal anterior pituitary samples from eight individuals without pituitary disease were studied. Gene expression of Wnt pathway activator (WNT4), inhibitors (SFRP1, DKK3, AXIN1, and APC), transcriptional activator (TCF7), target genes (MYC, WISP2, and, CDH1), and Wnt modulator (TP53) was evaluated by qPCR. β-Catenin, MYC, and WISP2 expression was determined by immunohistochemistry (IHC). The transcription levels of all genes studied, except APC, were higher in aCPs as compared to controls and TCF7 mRNA levels correlated with CTNNB1 mutation. CDH1 mRNA was overexpressed in tumor samples of patients with disease progression in comparison to those with stable disease. β-Catenin was positive and aberrantly distributed in 11 out of 14 tumor samples. Stronger β-catenin immunostaining associated positively with tumor progression. MYC positive staining was found in 10 out of 14 cases, whereas all aCPs were negative for WISP2. Wnt pathway genes were overexpressed in aCPs harboring CTNNB1 mutations and in patients with progressive disease. Recurrence was associated with stronger staining for β-catenin. These data suggest that Wnt pathway activation contributes to the pathogenesis and prognosis of aCPs.

Postnatal Ontogeny of the Circadian Expression of the Adrenal Clock Genes and Corticosterone Rhythm in Male Rats

The postnatal synchronization of the circadian variation of the adrenal clock genes in mammals remains unknown. We evaluated the postnatal ontogeny of daily variation of clock genes (Clock/Bmal1/Per1/Per2/Per3/Cry1/Cry2/Rorα/Rev-Erbα) and steroidogenesis-related genes (Star and Mc2r) in rat adrenals and its relationship with the emergence of plasma corticosterone rhythm using cosinor analysis. Plasma corticosterone circadian rhythm was detected from postnatal day (P)1, with morning acrophase, between zeitgeber time (ZT)0 and ZT2. From P14, there was a nocturnal acrophase of corticosterone at ZT20, which was associated with pups' eye opening. From P3 there was a circadian variation of the mRNA expression of Bmal1, Per2, Per3, and Cry1 genes with morning acrophase, whereas Rev-Erbα had nocturnal acrophase. From P14, Bmal1, Per2, Per3, and Cry1 acrophases advanced by approximately 10 hours, as compared with early neonatal days, becoming vespertine-nocturnal. In all postnatal ages, Per2 and Cry1 circadian profiles were synchronized in phase with the circadian rhythm of plasma corticosterone, whereas Bmal1 was in antiphase. An adult-like Star circadian rhythm profile was observed only from P21. In conclusion, our original data demonstrated a progressive postnatal maturation of the circadian variation of the adrenal clock genes in synchrony with the development of the corticosterone circadian rhythm in rats.

HPA axis dysregulation, NR3C1 polymorphisms and glucocorticoid receptor isoforms imbalance in metabolic syndrome

CONTEXT

Metabolic syndrome (MetS) shares several similarities with hypercortisolism.

OBJECTIVES

To evaluate hypothalamic-pituitary-adrenal (HPA) axis sensitivity to dexamethasone (DEX), NR3C1 single nucleotide polymorphisms (SNPs), and expression of glucocorticoid receptor (GR) isoforms and cytokines in peripheral immune cells of MetS patients and controls.

DESIGN

Prospective study with 40 MetS patients and 40 controls was conducted at the Ribeirão Preto Medical School University Hospital.

METHODS

Plasma and salivary cortisol were measured in basal conditions and after 0.25, 0.5, and 1 mg of DEX given at 2300 h. In addition, p.N363S (rs6195), p.ER22/23EK (rs6189-6190), and BclI (rs41423247) SNPs were evaluated by quantitative polymerase chain reaction allelic discrimination. Exons 3 to 9 and exon/intron boundaries of NR3C1 were sequenced. GR isoforms and cytokines (IL1B, IL2, IL4, IL6, IL8, IL10, IFNγ, TNFα) expression were assessed by quantitative polymerase chain reaction.

RESULTS

Plasma and salivary cortisol (nmol/L) after 1-mg DEX were higher in MetS patients compared with controls (PF: 70.2 ± 17.3 vs 37.9 ± 2.6, P = .02, and SF: 4.9 ± 1.7 vs 2.2 ± 0.3, P < .0001). After all DEX doses, a lower number of MetS patients suppressed plasma and salivary cortisol compared with controls. The BclI genotypic frequencies (%) differed between patients (CC:56/CG:44) and controls (CC:50/CG:32.5/GG:17.5) (P = .03). The GRβ was overexpressed (fold = 100.0; P = .002) and IL4 (fold = -265.0; P < .0001) was underexpressed in MetS.

CONCLUSION

MetS patients exhibited decreased HPA sensitivity to glucocorticoid feedback. Moreover, the BclI polymorphism lower frequency, GRβ overexpression, and IL4 underexpression might underlie the molecular mechanism of glucocorticoid resistance in MetS. Thus, HPA axis dysregulation might contribute to MetS pathogenesis.

Transcriptome Analysis Showed a Differential Signature between Invasive and Non-invasive Corticotrophinomas

ACTH-dependent hypercortisolism caused by a pituitary adenoma [Cushing's disease (CD)] is the most common cause of endogenous Cushing's syndrome. CD is often associated with several morbidities, including hypertension, diabetes, osteoporosis/bone fractures, secondary infections, and increased cardiovascular mortality. While the majority (≈80%) of the corticotrophinomas visible on pituitary magnetic resonance imaging are microadenomas (MICs, <10 mm of diameter), some tumors are macroadenomas (MACs, ≥10 mm) with increased growth potential and invasiveness, exceptionally exhibiting malignant demeanor. In addition, larger and invasive MACs are associated with a significant increased risk of local complications, such as hypopituitarism and visual defects. Given the clinical and molecular heterogeneity of corticotrophinomas, the aim of this study was to investigate the pattern of genetic differential expression between MIC and MAC, including the invasiveness grade as a criterion for categorizing these tumors. In this study, were included tumor samples from patients with clinical, laboratorial, radiological, and histopathological diagnosis of hypercortisolism due to an ACTH-producing pituitary adenoma. Differential gene expression was studied using an Affymetrix microarray platform in 12 corticotrophinomas, classified as non-invasive MIC (n = 4) and MAC (n = 5), and invasive MAC (n = 3), according to modified Hardy criteria. Somatic mutations in USP8 were also investigated, but none of the patients exhibited USP8 variants. Differential expression analysis demonstrated that non-invasive MIC and MAC have a similar genetic signature, while invasive MACs exhibited a differential expression profile. Among the genes differentially expressed, we highlighted CCND2, ZNF676, DAPK1, and TIMP2, and their differential expression was validated through quantitative real-time PCR in another cohort of 15 non-invasive and 3 invasive cortocotrophinomas. We also identified potential biological pathways associated with growth and invasiveness, TGF-β and G protein signaling pathways, DNA damage response pathway, and pathways associated with focal adhesion. Our study revealed a differential pattern of genetic signature in a subgroup of MAC, supporting a genetic influence on corticotrophinomas in patients with CD.

P27/CDKN1B Translational Regulators in Pituitary Tumorigenesis

In pituitary tumors, P27(CDKN1B) is underexpressed. We aimed to clarify whether translational regulation underlies this phenomenon. This study evaluated the expression of P27/CDKN1B, its targets (CCNE1, CDK2) and translational regulators (DKC1, RPS13, miR221, miR222) and screened for DKC1 variants in sporadic pituitary adenomas. Samples were obtained during transsphenoidal surgery from 48 patients with pituitary adenomas: 10 ACTH-, 17 GH-secreting, and 21 nonfunctioning (NFPA). The control group comprised 7 normal pituitaries (NP) obtained during autopsies. Gene expression was assessed by RT-PCR and protein expression by immunohistochemistry. The 15 exons of DKC1 were sequenced. P27 protein underexpression was observed in all adenomas subtypes (p=0.001). CCNE1 mRNA (p=0.01) overexpression, but not protein, was observed in NFPA. No differential gene expression among groups was observed in CDKN1B regulators RPS13 (p=0.23) and DKC1 (p=0.34). The expression of miR221 and miR222 was similar among tumors and NP. Frequent DKC1 variants (SNPs) were found in exon 14 and in the 3'-UTR in similar frequency to NCBI-dsSNP databases. We also observed rare DKC1 variants in 11% of the studied tumor samples, indicating a high prevalence in pituitary adenomas, however, in silico studies failed to indicate deleterious effects. The high frequency of DKC1 variants may influence, in some extent, pituitary tumors development, without clear role in its tumorigenesis. Our data reinforce the P27 underexpression in pituitary adenomas and provide further evidence of the post-translational machinery involvement, although this phenomenon cannot be explained either by mis-expression of P27 translational regulators - DKC1, RPS13, miR221, miR222 - or directly by DKC1 mutations.

Telomere length and telomerase expression in pituitary tumors

PURPOSE

Telomere dysfunction and telomerase activation underlie cancer transformation. This study aims to investigate the contribution of telomere biology to pituitary tumor behavior.

SUBJECTS AND METHODS

Samples from 50 patients with pituitary tumors (11 ACTH-secreting, 18 GH-secreting, and 21 non-secreting tumors) and 7 subjects without pituitary lesions were collected. The expressions of telomerase essential components TERT and TERC and tumor telomere content were measured by quantitative PCR techniques.

RESULTS

Telomerase (TERT) expression was detected in 36% of tumors. No correlation was observed between TERT and TERC expression level and tumor size in any tumor type. There was no association between gene expression and clinical findings. Telomere content (T/S ratio) was similar between pituitary adenomas (0.39 ± 0.16) and normal pituitaries (0.47 ± 0.12; p = 0.24) and also was between the different adenoma types: ACTH-secreting (0.43 ± 0.08), GH-secreting (0.31 ± 0.12), and non-secreting (0.42 ± 0.20; p = 0.10) tumors.

CONCLUSIONS

The telomere content and expression of telomerase components are comparable between normal pituitary glands and tumor tissues, suggesting that telomere biology does not play an important role in pituitary tumor development.

A novel ADIPOQ mutation (p.M40K) impairs assembly of high-molecular-weight adiponectin and is associated with early-onset obesity and metabolic syndrome

CONTEXT

The phenotypic effects of ADIPOQ mutations early in life, prior to type 2 diabetes onset, have not been studied.

AIM

The objective of the study was to characterize the impact of a novel ADIPOQ mutation in vitro and in vivo.

DESIGN

The design of the study was ADIPOQ screening, adiponectin oligomerization, and cardiometabolic phenotype assessment.

SUBJECTS

Fourteen hypoadiponectinemic (<3 μg/mL) and 686 normoadiponectinemic young adults (23-25 y) were prospectively followed up since birth.

MAIN OUTCOME MEASURES

Human and recombinant murine mutant adiponectin oligomerization, the proband's ADIPOQ and ADIPOR1/R2 adipose tissue (AT) expression, and cardiometabolic profile were measured.

RESULTS

The heterozygous ADIPOQ p.M40K mutation was identified in one hypoadiponectinemic male (2.4 μg/mL) and three other family members. Carriers presented a marked reduction of serum high-molecular weight to total adiponectin ratio when compared with controls (9.4% ± 1% vs 56.6% ± 13%; P < .05) and family noncarriers (9.4% ± 1% vs 42% ± 0.5%; P = .05). Both mRNA and protein levels of adiponectin were increased in the AT of the proband (2.3- and 1.6-fold, respectively). However, the high-molecular weight to total adiponectin ratio of adiponectin was decreased (3.3-fold). Moreover, the expressions of ADIPOR1 and ADIPOR2 were significantly down-regulated in the AT of the proband (6- and 1.2-fold, respectively). The results were confirmed by in vitro studies on the recombinant murine homologous mutation (p.M43K). The proband's cardiometabolic phenotype progression was further characterized: born small for gestational age and adolescence-onset obesity; insulin resistance (homeostasis assessment model of insulin resistance of 4.7), and dyslipidemia at 25 years; decreased high-molecular weight adiponectin (0.24 μg/mL = 10%), hypertension (180/120 mm Hg), steatosis (fat liver = 40% ± 6%), increased carotid intima-media thickness at 31 years, and type 2 diabetes (glycosylated hemoglobin = 6.6%) at 34 years of age. Of note, all of the affected family members presented features of metabolic syndrome.

CONCLUSION

The newly identified ADIPOQ p.M40K mutation associates with severe cardiometabolic dysfunction due to the impairment of high-molecular weight adiponectin complex formation.

SAGE analysis highlights the putative role of underexpression of ribosomal proteins in GH-secreting pituitary adenomas

BACKGROUND

Although the molecular pathogenesis of pituitary adenomas has been assessed by several different techniques, it still remains partially unclear. Ribosomal proteins (RPs) have been recently related to human tumorigenesis, but they have not yet been evaluated in pituitary tumorigenesis.

OBJECTIVE

The aim of this study was to introduce serial analysis of gene expression (SAGE), a high-throughput method, in pituitary research in order to compare differential gene expression.

METHODS

Two SAGE cDNA libraries were constructed, one using a pool of mRNA obtained from five GH-secreting pituitary tumors and another from three normal pituitaries. Genes differentially expressed between the libraries were further validated by real-time PCR in 22 GH-secreting pituitary tumors and in 15 normal pituitaries.

RESULTS

Computer-generated genomic analysis tools identified 13,722 and 14,993 exclusive genes in normal and adenoma libraries respectively. Both shared 6497 genes, 2188 were underexpressed and 4309 overexpressed in tumoral library. In adenoma library, 33 genes encoding RPs were underexpressed. Among these, RPSA, RPS3, RPS14, and RPS29 were validated by real-time PCR.

CONCLUSION

We report the first SAGE library from normal pituitary tissue and GH-secreting pituitary tumor, which provide quantitative assessment of cellular transcriptome. We also validated some downregulated genes encoding RPs. Altogether, the present data suggest that the underexpression of the studied RP genes possibly collaborates directly or indirectly with other genes to modify cell cycle arrest, DNA repair, and apoptosis, leading to an environment that might have a putative role in the tumorigenesis, introducing new perspectives for further studies on molecular genesis of somatotrophinomas.

Prognostic value of cardiac troponin I in patients with COPD acute exacerbation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is frequently associated with right ventricular loading and pulmonary hypertension. We aimed to evaluate a possible association between cardiac troponin I (cTnI) levels and adverse events in hospitalised patients with acute exacerbation of COPD .

METHODS

Retrospective cohort study, with analysis of admissions for acute exacerbation of COPD , with cTnI obtained in the first 48 hours of admission. A positive cTnI test was defined as 0.012 ng/ml or higher (99th percentile). Baseline and peak troponin I levels were taken as independent variables, and outcome variables included length of hospital stay, complications during hospitalisation, and in-hospital and extra-hospital mortality (evaluated 18 months post-discharge).

RESULTS

Data concerned 173 patients (105 male, 68 female), with a median age of 77 years (interquartile range of 11 years). The median baseline cTnI was 0.030 ng/ml (n=173), and the median peak cTnI was 0.040 ng/ml (n=173; absolute peak value of 1.260 ng/ml). Nearly 70% of cases had a positive cTnI at admission. Both baseline and peak cTnI correlated significantly with the need for noninvasive ventilatory support. We were not able to find significant differences in in-hospital survival associated with the two troponin groups, but overall 18-month survival was significantly higher among patients with lower values of baseline and peak cTnI.

CONCLUSIONS

In patients hospitalised for acute COPD exacerbations, elevated baseline and peak cTnI were associated with a greater need for noninvasive ventilatory support and were significant predictors of 18-month overall survival.

Determination of neutral polymorphisms (frameworks) of the human beta globin gene in beta thalassaemias by PCR/DGGE

PURPOSE

Considering the importance of type beta thalassaemias as hereditary syndromes of high significance in different populations of Mediterranean origin and, by extension, in the Brazilian population, the objective of the present study was to determine by PCR/DGGE the gene structures responsible for neutral polymorphisms (frameworks) observed in the human beta globin gene associated with the mutations responsible for type beta thalassaemias in a sample of the Brazilian population and, more specifically, of the population of the State of São Paulo.

PATIENTS AND METHODS

Thirty individuals with beta thalassaemic mutations were analyzed: 22 mutations were in codon 39 (C-->T), 5 in IVS1-110 (G-->A), 2 in IVS1-6 (T-->C) and 1 in IVS1-1 (G-->A). DNA was extracted and selective amplification was performed by PCR extending from position IVS1 nt 46 to IVS2 nt 126 (474 pb). The product was then analyzed by polyacrylamide gel electrophoresis on a denaturing 10-60% urea/formamide gradient.

RESULTS

The results demonstrated that, as expected, the mutations responsible for type beta thalassaemia observed in this population are of Mediterranean origin, with 73% distribution represented by codon 39, 17% by IVS1-110, 7% by IVS1-6 and 3% by IVS1-1. In turn, framework distribution seems to indicate a higher frequency of Fr 1-1 in codon 39 and IVS1-110, of Fr 1-3 in IVS1-6 and of Fr 1-2 in IVS1-1.

CONCLUSIONS

These results permit us to conclude that gene amplification by PCR followed by DGGE is an appropriate method for the separation of DNA molecules that differ even by a single base change and therefore can be utilized to detect the alterations observed in the human beta globin gene. This methodology shows that, using only a pair of primers, it is possible to define the frameworks that are observed in the beta globin gene.

[Management of a case of maple syrup urine disease--the use of gluco-insulinotherapy]

We report here the treatment and poor outcome of a case of Maple Syrup Urine Disease with late diagnosis and retrieval (2 and 5 months, respectively). As the proband had quite high levels of plasmatic leucine (1956 micromol/L for a normal upper limit of 77), we started immediately with a gluco-insulin therapy to produce anabolism in the infant. When leucine has fallen to 275.3 micromol/L, we instituted feeding with branched chain amino acid-free protein and high energy from carbohydrates. After reviewing briefly the clinical, biochemical and therapeutic aspects of this disorder, we comment on the great difficulties of making early diagnosis and of obtaining the specific dietetic formulas to Maple Syrup Urine Disease, in Brazil.

Frequency of the cystic fibrosis delta F 508 mutation in a population from São Paulo State, Brazil

Cystic fibrosis (CF) nonrelated patients (N = 24) from São Paulo State, Brazil, were screened for the presence of the delta F 508 mutation by PCR amplification of the deletion region with the primers C16B (5'GTTTTCCTGGATTATGCCTGGGCAC3') and C16D (5'GTTGGCATGCTTTGATGACGCTTC 3'), and by acrylamide gel electrophoresis. The allelic frequency of the delta F 508 mutation was 33% (15/48 chromosomes). The genotype distribution among the patients showed 12.5% (N = 3) of delta F 508 homozygotes, 37.5% (N = 9) of delta F heterozygotes and 50% (N = 12) of non-carriers of the mutation. The frequency observed in this study is lower than that estimated for the North American and North European population (75% to 80%) and is similar to that described in Southern Europe (25% to 50%) which is consistent with the origins of this population.