János Horányi

Integrative molecular bioinformatics study of human adrenocortical tumors: microRNA, tissue-specific target prediction, and pathway analysis

MicroRNAs (miRs) are involved in the pathogenesis of several neoplasms; however, there are no data on their expression patterns and possible roles in adrenocortical tumors. Our objective was to study adrenocortical tumors by an integrative bioinformatics analysis involving miR and transcriptomics profiling, pathway analysis, and a novel, tissue-specific miR target prediction approach. Thirty-six tissue samples including normal adrenocortical tissues, benign adenomas, and adrenocortical carcinomas (ACC) were studied by simultaneous miR and mRNA profiling. A novel data-processing software was used to identify all predicted miR-mRNA interactions retrieved from PicTar, TargetScan, and miRBase. Tissue-specific target prediction was achieved by filtering out mRNAs with undetectable expression and searching for mRNA targets with inverse expression alterations as their regulatory miRs. Target sets and significant microarray data were subjected to Ingenuity Pathway Analysis. Six miRs with significantly different expression were found. miR-184 and miR-503 showed significantly higher, whereas miR-511 and miR-214 showed significantly lower expression in ACCs than in other groups. Expression of miR-210 was significantly lower in cortisol-secreting adenomas than in ACCs. By calculating the difference between dCT(miR-511) and dCT(miR-503) (delta cycle threshold), ACCs could be distinguished from benign adenomas with high sensitivity and specificity. Pathway analysis revealed the possible involvement of G2/M checkpoint damage in ACC pathogenesis. To our knowledge, this is the first report describing miR expression patterns and pathway analysis in sporadic adrenocortical tumors. miR biomarkers may be helpful for the diagnosis of adrenocortical malignancy. This tissue-specific target prediction approach may be used in other tumors too.

Analysis of circulating microRNAs in adrenocortical tumors

Differential diagnosis of adrenocortical adenoma (ACA) and carcinoma is of pivotal clinical relevance, as the prognosis and clinical management of benign and malignant adrenocortical tumors (ACTs) is entirely different. Circulating microRNAs (miRNAs) are promising biomarker candidates of malignancy in several tumors; however, there are still numerous technical problems associated with their analysis. The objective of our study was to investigate circulating miRNAs in ACTs and to evaluate their potential applicability as biomarkers of malignancy. We have also addressed technical questions including the choice of profiling and reference gene used. A total of 25 preoperative plasma samples obtained from patients with ACAs and carcinomas were studied by microarray and quantitative real-time PCR. None of the three miRNAs (hsa-miR-192, hsa-mir-197 and hsa-miR-1281) found as differentially expressed in plasma samples in our microarray screening could be validated by quantitative real-time PCR. In contrast, of the selected eight miRNAs reported in the literature as differentially expressed in ACT tissues, five (hsa-miR-100, hsa-miR-181b, hsa-miR-184, hsa-miR-210 and hsa-miR-483-5p) showed a statistically significant overexpression in adrenocortical cancer vs adenoma when normalized on hsa-miR-16 as a reference gene. Receiver operator characteristic analysis of data revealed that the combination of dCThsa-miR-210 - dCThsa-miR-181b and dCThsa-miR-100/dCThsa-miR-181b showed the highest diagnostic accuracy (area under curve 0.87 and 0.85, respectively). In conclusion, we have found significant differences in expression of circulating miRNAs between ACAs and carcinomas, but their diagnostic accuracy is not yet high enough for clinical application. Further studies on larger cohorts of patients are needed to assess the diagnostic and prognostic potential application of circulating miRNA markers.

Diagnostic performance of salivary cortisol and serum osteocalcin measurements in patients with overt and subclinical Cushing's syndrome

OBJECTIVE The cut-off value for salivary cortisol measurement for the diagnosis of Cushings syndrome (CS) may depend both on the severity of the disease and the composition of control group. Therefore, we examined the utility of midnight salivary cortisol measurements in patients who were evaluated for signs and symptoms of CS or because they had adrenal incidentalomas. Because serum osteocalcin (OC) is considered as a sensitive marker of hypercortisolism, we also investigated whether OC could have a role in the diagnosis of CS. PATIENTS AND METHODS Each of the 151 patients was included into one of the following groups: (A) overt CS (n=23), (B) subclinical CS (n=18), (C) inactive adrenal adenomas (n=40), (D) patients without HPA disturbances (n=70). Patients (C+D) were used as controls. Serum, salivary and urinary cortisol, and OC were measured by electrochemiluminescence immunoassay. RESULTS Group A had suppressed OC as compared to both group B and group (C+D). Serum and salivary cortisol concentrations showed strong negative correlations with OC in patients with overt CS. The areas under the curves of salivary and serum cortisol at 24:00 h (0.9790 and 0.9940, respectively) serum cortisol after low dose dexamethasone test (0.9930) and OC (0.9220) obtained from ROC analysis for the diagnosis of overt CS were not statistically different. CONCLUSION This study confirms the usefulness of midnight salivary cortisol measurements in the diagnosis of overt CS in the everyday endocrinological praxis. Our results suggest that OC may have a role in the diagnosis of overt CS.

Novel mutation of the CYP17 gene in two unrelated patients with combined 17α-hydroxylase/17,20-lyase deficiency: Demonstration of absent enzyme activity by expressing the mutant CYP17 gene and by three-dimensional modeling

The CYP17 gene, located on chromosome 10q24-q25, encodes the cytochrome P450c17 enzyme. Mutations of this gene cause the 17alpha-hydroxylase/17,20-lyase deficiency, which is a rare, autosomal recessive form of congenital adrenal hyperplasia. Approximately 50 different mutations of the CYP17 gene have been described, of which some mutations have been identified in certain ethnic groups. In this study, we present the clinical history, hormonal findings and mutational analysis of two patients from unrelated families, who were evaluated for hypertension, hypokalemia and sexual infantilism. In the first patient, who was a 37-year-old female, additional studies showed a large myelolipoma in the left adrenal gland, and a smaller tumor in the right adrenal gland. In the second patient, who was a 31-year-old phenotypic female, clinical work-up revealed a 46,XY kariotype, absence of ovaries and presence of testes located in the inner opening of both inguinal canals. Analysis of the CYP17 gene by polymerase chain reaction amplification and direct sequencing demonstrated a novel homozygous mutation of codon 440 from CGC (Arg) to TGC (Cys) in both patients. The effect of this novel mutation on 17alpha-hydroxylase/17,20-lyase activity was assessed by in vitro studies on the mutant and wild-type P450c17 generated by site-directed mutagenesis and transfected in nonsteroidogenic COS-1 cells. These studies showed that the mutant P450c17 protein was produced in transfected COS-1 cells, but it had negligible 17alpha-hydroxylase and 17,20-lyase activities. In addition, three-dimensional computerized modeling of the heme-binding site of the P450c17 enzyme indicated that replacement of Arg by Cys at amino acid position 440 predicts a loss of the catalytic activity of the enzyme, as the mutant enzyme containing Cys440 fails to form a hydrogen bond with the propionate group of heme, which renders the mutant enzyme unable to stabilize the proper position of heme. Based on these findings we conclude that expressing the CYP17 gene with functional analysis, combined with three-dimensional computerized modeling of the heme-binding site of the protein provide feasible tools for molecular characterizing of functional consequences of the novel CYP17 mutation on enzyme function.

Marked Increase in CYP24A1 Gene Expression in Human Papillary Thyroid Cancer

The active metabolite of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25-D3) inhibits cell growth and induces cell differentiation and apoptosis in numerous tumors, such as colon, breast, and prostate cancers (1–3). However, the anticancer effect of 1,25-D3 cannot always be seen in a clinical setting. In case of colon cancers, a marked increase in the expression of the 1,25D3 inactivating enzyme, the 24-hydroxylase (CYP24A1), has been observed (4). The role of 1,25-D3 in the development of thyroid carcinomas has not yet been established. However, Sharma et al. (5) observed the correlation of high baseline CYP24A1 and relatively low stimulation after calcitriol treatment (compared with sensitive cells) with lack of growth inhibition in numerous thyroid cancer cell lines. We have also examined the gene expression of the inactivating CYP24A1 and the activating 1-alpha-hydroxylase (CYP27B1) enzyme in human thyroid cancers. To date, gene expression analysis of thyroid samples (both normal and papillary tumor tissue of the same patient) was carried out in six unrelated, consecutive, Hungarian, Caucasian patients at our Thyroid Clinic. All surgically removed thyroid tissue samples underwent histological examination, and papillary tumor was identified in all cases. The study was approved by the Regional Committee of Science and Research Ethics, Semmelweis University (SOTE-TUKEB 1160-0/20101018EKU), and all patients gave written informed consent. Total RNA was isolated from each sample with Roche High Pure Total RNA Isolation kit. Five hundred nanograms of total RNA was reverse-transcribed to cDNA. The expression differences of selected genes were analyzed by Taqman probe-based quantitative real-time reverse transcriptase– polymerase chain reaction. Relative quantification was carried out from collected data (threshold cycle numbers) by Applied Biosystems 7500 System SDS software 1.3. CYP24A1 mRNA expression was markedly increased in all but one papillary cancer compared with that of normal thyroid tissue, sometimes reaching 300-fold elevation (Supplementary Fig. S1; Supplementary Data are available online at www.liebertonline.com/thy). No significant alteration was seen in CYP27B1 gene activity between neoplastic and normal tissues. There was no significant difference in serum 25-OHvitamin D3 concentrations among patients (mean: 28.03 ng/ mL, range: 22.7–31.9 ng/mL). In this letter, we report marked increases in the 1,25-D3neutralizing CYP24A1 gene expression in human papillary thyroid cancer. The tumor cell growth-inhibiting role of vitamin D3 has been extensively studied in different malignancies (1–3). The interest in the association of vitamin-D3 serum levels with various cancer incidences has dramatically increased. However, only very limited data are available on the relationship between serum vitamin D3 concentrations and malignant thyroid conditions (6,7). The pilot study of Laney et al. showed levels of vitamin D and rates of vitamin D deficiency to be similar between patients with thyroid nodules, thyroid cancer in remission, and active thyroid cancer (8). However, the results of Stepien et al. revealed significantly lower calcitriol concentrations in patients with papillary, follicular, and anaplastic thyroid cancers (7). This finding could be attributable to higher CYP24A1 levels cleaving calcitriol, as there were no differences in serum 25-OH-vitamin D3. Earlier, calcitriol had also been shown to attenuate thyrotropinstimulated growth and iodide uptake by rat thyroid cells (FRTL-5) (9,10). Papillary cancer is the most common thyroid malignancy. The role of vitamin D3 in the prevention or development of this disorder has to be yet determined. The increase in CYP24A1 expression in this cancer type could be a ‘‘protective’’ mechanism against the well-known anticancer effect of calcitriol. The observation of Sharma et al. (5) regarding increased expression of CYP24A1 in thyroid cancer cell lines corroborates this notion. One of the cell lines they used was human papillary thyroid carcinoma cell line, whereas the other ones showed the features of human anaplastic thyroid carcinoma. Also, the most resistant cell lines to calcitriol had the highest baseline levels of CYP24A1. In our study at this stage, the number of examined tumor tissues does not allow drawing of statistically significant conclusion about the correlation of tumor histopathological stage or aggressiveness with CYP24A1 levels. Khadzkou et al. demonstrated enhanced 1-alphahydroxylase expression but concluded that this elevation did not show large differences in CYP27B1 expression in papillary thyroid cancer and its metastasis compared with normal

Parathyroid surgical failures with misleading falls of intraoperative parathyroid hormone levels

According to earlier reports, a decrease below 50% of baseline of intraoperative PTH levels measured 5 min after resection of the parathyroid adenoma predicts a cure of hyperparathyroidism. To reveal previously unrecognized pitfalls of intraoperative PTH measurements, we reviewed surgical failures in our series of parathyroidectomies combined with intraoperative PTH sampling. PTH measurements were performed in 251 patients with primary hyperparathyroidism (PHPT) between November 1999 and December 2002. PHPT due to parathyroid hyperplasia were found in 8 cases, double parathyroid adenomas in 6 cases, parathyroid carcinoma in 1 case and single parathyroid adenomas in 236 cases, all confirmed by histological examination. Of the 236 cases of single adenomas, initial surgery failed to cure PHPT in 4 patients. In 3 patients a false-positive decrease of intraoperative PTH (from 269 to 40 pg/ml, from 211 to 27 pg/ml, and from 140 to 59 pg/ml) was observed, whereas in the fourth patient a truenegative decrease of intraoperative PTH (from 758 to 401 pg/ml) was mistakenly interpreted as indication for a cure of PHPT. In each of the 4 patients in whom initial surgery failed the intervention included thyroid surgery and reoperative parathyroid surgery resulted in a permanent cure of PHPT. These observations support the possibility that thyroid surgery may compromise the blood supply of parathyroid adenomas resulting in a misleading drop of intraoperative PTH levels. Therefore, a careful evaluation of intraoperative PTH levels and, perhaps, other intraoperative aids such as histological evaluation of frozen sections are recommended when parathyroid surgery is combined with simultaneous thyroid intervention

Functional genomics approaches for the study of sporadic adrenal tumor pathogenesis: Clinical implications

Although sporadic adrenal tumors are frequently encountered in the general population their pathogenesis is not well elucidated. The advent of functional genomics/bioinformatics tools enabling large scale comprehensive genome expression profiling should contribute to significant progress in this field. Some studies have already been published describing gene expression profiles of benign and malignant adrenocortical tumors and phaeochromocytomas. Several genes coding for growth factors and their receptors, enzymes involved in steroid hormone biosynthesis, genes related to the regulation of cell cycle, cell proliferation, adhesion and intracellular metabolism have been found to be up- or downregulated in various tumors. Some alterations in gene expression appear so specific for certain tumor types that their application in diagnosis, determination of prognosis and the choice of therapy can be envisaged. In this short review, the authors will present a synopsis of these recent findings that seem to open new perspectives in adrenal tumor pathogenesis, with emphasis on changes in steroidogenic enzyme expression profiles and highlighting possible clinical implications.

Expression of glucocorticoid receptor isoforms in human adrenocortical adenomas

INTRODUCTION Glucocorticoid receptor (GR) is expressed in the normal human adrenal gland, however, no study has been performed to evaluate the separate expression of alpha- and beta-isoforms (GRalpha and GRbeta) in normal human adrenals and in adrenocortical adenomas. EXPERIMENTAL GRalpha and GRbeta mRNA expression was examined by quantitative real-time PCR in 31 adrenal tissues including 19 non-functioning adenomas (NFA), 6 cortisol-producing adenomas (CPA) and 6 normal adrenocortical tissues. In addition, the presence and cellular localization of GRalpha and GRbeta proteins in adrenal tissues were studied by immunohistochemistry. RESULTS Compared to normal adrenocortical tissues, both GRalpha and GRbeta mRNAs were significantly increased in CPA but not in NFA. Using anti-GRalpha antibody a strong nuclear staining was observed in NFA and CPA, and a less remarkable immunoreactivity was detected in some nuclei of normal adrenocortical cells. GRbeta immunostaining was absent in normal adrenal tissues and NFA, while a strong cytoplasmic and nuclear immunoreaction was found in CPA. CONCLUSIONS Altered expression of GRalpha and GRbeta in CPA raises their possible role in the pathophysiology of these adrenal tumors, although further studies are needed to elucidate the potential significance of these findings.

Differences in the expression of histamine-related genes and proteins in normal human adrenal cortex and adrenocortical tumors

Histamine is involved in the pathogenesis of several tumors; however, there are no data on its possible involvement in human adrenocortical tumorigenesis. The expression of genes and proteins involved in the biosynthesis (histidine decarboxylase, HDC), action (histamine receptors: HRH1–HRH4), and metabolism of histamine is largely unknown both in the normal human adrenal cortex and in adrenocortical tumors. In this study, we examined the expression of histamine-related genes and proteins and histamine content in normal adrenal cortex, benign adrenocortical adenomas, and malignant adrenocortical cancer (ACC). Fifteen normal adrenals and 43 tumors were studied. mRNA expression was examined by real time RT-PCR. Western-blotting and immunohistochemistry were used for the study of proteins. Tissue histamine content was determined by enzyme-linked immunosorbent assay. We found that all proteins involved in histamine biosynthesis and action are present both in the normal adrenal cortex and in the tumors studied. HDC expression and histamine content was highest in the normal tissues and lower in benign tumors, whereas it was significantly less in ACCs. HRH3 expression was significantly higher in ACC samples than in the other groups. Adrenocortical tumorigenesis might, thus, be characterized by reduced histamine biosynthesis; furthermore, different adrenocortical tumor subtypes may show unique histamine receptor expression profiles.

Comparative study of somatic oncogene mutations in normal thyroid tissues and thyroid neoplasms

Az elmult evekben tobb munkacsoportnak sikerult olyan szomatikus mutaciokat (BRAF, NRAS, HRAS, KRAS genekben) es genatrendeződeseket (RET/PTC, PAX8/PPAR-gamma) azonositani, amelyek osszefuggest mutatnak a pajzsmirigydaganatok kialakulasaval. Jelen vizsgalatban 11 szemely 22 (11 koros es 11 betegsegmentes) intraoperativ pajzsmirigy-szovetmintait elemeztek. A RAS gencsalad es a BRAF genek szomatikus egypontos nukleotid polimorfizmusait LigthCycler olvadaspontanalizis-modszerrel, mig a genatrendeződeseket valos idejű polimeraz lancreakcio modszerevel vizsgaltak. A daganatos mintakban 3 BRAF-, 2 NRAS-, 1 HRAS-mutaciot, valamint 1 RET/PTC1 atrendeződest talaltak. Az eredmenyek megerősitik a nemzetkozi adatokat, miszerint ezek az egypontos nukleotidpolimorfizmusok es genatrendeződesek megtalalhatok a daganatos pajzsmirigyszovetekben. Valoszinűsithető, hogy ezen genetikai vizsgalatokkal kiegeszult citologiai vizsgalat segitheti a malignus gobok azonositasat, illetve elkepzelhető, hogy prognosztikai faktorkent el...It is established that numerous somatic oncogene mutation (BRAF, NRAS, HRAS, KRAS) and gene translocations (RET/PTC, PAX8/PPAR-gamma) are associated with the development of thyroid cancer. In this study 22 intraoperative thyroid tissue samples (11 pathologic and 11 normal) were examined. Somatic single nucleotide polymorphisms were analyzed by LigthCycler melting method, while translocations were identified by real-time polymerase chain reaction technique. In tumorous sample 3 BRAF, 2 NRAS and one HRAS mutations were found, as well as one RET/PTC1 translocation. Results confirm international data showing that these oncogene mutations and translocations are linked to thyroid cancer. Cytological examination completed with genetic data may support the diagnosis of thyroid malignancies. In addition, genetic alterations may indicate malignant transformation and may become prognostic factors in future.