Aberrant epigenetics is a hallmark of cancer, and endocrine-related tumors are no exception. Recent research has been identifying an ever-growing number of epigenetic alterations in both genomic DNA methylation and histone post-translational modification in tumors of the endocrine system. Novel microarray and ultra-deep sequencing technologies have allowed the identification of genome-wide epigenetic patterns in some tumor types such as adrenocortical, parathyroid, and breast carcinomas. However, in other cancer types, such as the multiple endocrine neoplasia syndromes and thyroid cancer, tumor information is limited to candidate genes alone. Future research should fill this gap and deepen our understanding of the functional role of these alterations in cancer, as well as defining their possible clinical uses.
Sandra Rodríguez-Rodero, Elías Delgado-Álvarez, Agustín F Fernández, Juan L Fernández-Morera, Edelmiro Menéndez-Torre, and Mario F Fraga
O Chabre, R Libé, G Assie, O Barreau, J Bertherat, X Bertagna, J-J Feige, and N Cherradi
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 six adrenocortical adenomas (ACAs), six naACCs, and six aACCs. Eight miRNAs were selected for further validation by quantitative RT-PCR (ten ACAs, nine naACCs, nine aACCs, and three normal adrenals). Serum levels of five miRNAs were measured in samples from 56 subjects (19 healthy controls (HC), 14 ACA, nine 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 HC. MiR-139-5p and miR-376a levels were significantly increased in aACC compared with naACC patients in tumor samples only. Tissue miR-483-5p was markedly upregulated in a majority of ACC compared with ACA patients or HC, 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, this study reports for the first time that circulating miR-483-5p and miR-195 are promising noninvasive biomarkers with a highly specific prognostic value for the clinical outcome of ACC patients.
T M A Kerkhofs, M H T Ettaieb, I G C Hermsen, and H R Haak
Cancer of the adrenal cortex (ACC) is a rare endocrine malignancy with limited treatment options. Patients typically present with autonomous hormonal overproduction and/or a large abdominal mass. Hormonal assays and medical imaging can be diagnostic, but urinary steroid profiling might be a more sensitive technique to assess malignancy in adrenal tumours. The stage of the disease at diagnosis is the most important prognostic factor. The current staging system needs refinement, especially to separate aggressive from indolent disease in stage IV patients and to select patients who need adjuvant treatment after complete surgical resection. Regarding the latter, assessing the proliferation index Ki-67 seems the best tool currently available. Genomic profiling is expected to become of clinical relevance in the future. Medical therapy is centred on the adrenolytic drug mitotane, which carries considerable toxicity and is not easy to manage. Its tolerability and long plasma level build-up phase may be improved by therapeutic drug monitoring based on pharmacokinetic modelling and intensive counselling of patients. Current chemotherapy regimens can offer disease stabilization in about 50% of patients, but an objective response should be expected in <25%. Research on targeted therapy and immunotherapy is difficult in this rare disease with often heavily pre-treated patients and has not yet been successful. Quality of care should be ensured by treating patients in centres with established experience in multidisciplinary oncologic care, who adhere to prevailing guidelines and state-of-the-art in diagnostic and treatment concepts. International collaboration in fundamental research and clinical trials is the key to further elucidate the pathogenesis and to improve patient care.
Bruno Ragazzon, Guillaume Assié, and Jérôme Bertherat
Transcriptome analysis has been successfully used to study the gene profile expression of adrenocortical tumors (ACT) for 7 years. The various studies reported to date have produced an abundance of new information on adrenocortical cancer (ACC), underlying the validity of this approach to study the molecular genetics and pathogenesis of these tumors. The gene expression profile of ACC clearly differs from that of benign adrenocortical adenomas (ACA). Interestingly, transcriptome analysis has the ability to establish a subclassification of ACC based on the gene expression profile. In particular, it is able to identify two groups of tumors with different outcomes (i.e. good prognosis and poor prognosis). This approach has been used to develop molecular markers for ACC diagnosis and prognostication. An IGF2 cluster of genes up-regulated in ACC has been identified. Transcriptome analysis has shown that, in comparison with ACA, IGF2 is indeed the gene most overexpressed in ACC. By contrast, genes associated with steroidogenesis are down-regulated in ACC. Genes controlling the cell cycle are dysregulated in ACC, and several are dramatically overexpressed. Analysis regarding the level of expression of Wnt/β-catenin and p53 signaling has shown alterations, in keeping with the known molecular somatic genetic defects of these pathways that are observed in ACC. This review summarizes the main findings of studies reporting ACC transcriptome analysis, demonstrating its power for ACT classification, and examines the resulting progress in understanding the pathogenesis of ACC. The potential for both ACC diagnosis and the identification of new therapeutic targets will be discussed.
S G Creemers, P M van Koetsveld, F J van Kemenade, T G Papathomas, G J H Franssen, F Dogan, E M W Eekhoff, P van der Valk, W W de Herder, J A M J L Janssen, R A Feelders, and L J Hofland
Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis. Discrimination of ACCs from adrenocortical adenomas (ACAs) is challenging on both imaging and histopathological grounds. High IGF2 expression is associated with malignancy, but shows large variability. In this study, we investigate whether specific methylation patterns of IGF2 regulatory regions could serve as a valuable biomarker in distinguishing ACCs from ACAs. Pyrosequencing was used to analyse methylation percentages in DMR0, DMR2, imprinting control region (ICR) (consisting of CTCF3 and CTCF6) and the H19 promoter. Expression of IGF2 and H19 mRNA was assessed by real-time quantitative PCR. Analyses were performed in 24 ACCs, 14 ACAs and 11 normal adrenals. Using receiver operating characteristic (ROC) analysis, we evaluated which regions showed the best predictive value for diagnosis of ACC and determined the diagnostic accuracy of these regions. In ACCs, the DMR0, CTCF3, CTCF6 and the H19 promoter were positively correlated with IGF2 mRNA expression (P<0.05). Methylation in the most discriminating regions distinguished ACCs from ACAs with a sensitivity of 96%, specificity of 100% and an area under the curve (AUC) of 0.997±0.005. Our findings were validated in an independent cohort of 9 ACCs and 13 ACAs, resulting in a sensitivity of 89% and a specificity of 92%. Thus, methylation patterns of IGF2 regulatory regions can discriminate ACCs from ACAs with high diagnostic accuracy. This proposed test may become the first objective diagnostic tool to assess malignancy in adrenal tumours and facilitate the choice of therapeutic strategies in this group of patients.
Brian Harding, Manuel C Lemos, Anita A C Reed, Gerard V Walls, Jeshmi Jeyabalan, Michael R Bowl, Hilda Tateossian, Nicky Sullivan, Tertius Hough, William D Fraser, Olaf Ansorge, Michael T Cheeseman, and Rajesh V Thakker
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized in man by parathyroid, pancreatic, pituitary and adrenal tumours. The MEN1 gene encodes a 610-amino acid protein (menin) which is a tumour suppressor. To investigate the in vivo role of menin, we developed a mouse model, by deleting Men1 exons 1 and 2 and investigated this for MEN1-associated tumours and serum abnormalities. Men1 +/− mice were viable and fertile, and 220 Men1 +/− and 94 Men1 +/+ mice were studied between the ages of 3 and 21 months. Survival in Men1 +/− mice was significantly lower than in Men1 +/+ mice (<68% vs >85%, P<0.01). Men1 +/− mice developed, by 9 months of age, parathyroid hyperplasia, pancreatic tumours which were mostly insulinomas, by 12 months of age, pituitary tumours which were mostly prolactinomas, and by 15 months parathyroid adenomas and adrenal cortical tumours. Loss of heterozygosity and menin expression was demonstrated in the tumours, consistent with a tumour suppressor role for the Men1 gene. Men1 +/− mice with parathyroid neoplasms were hypercalcaemic and hypophosphataemic, with inappropriately normal serum parathyroid hormone concentrations. Pancreatic and pituitary tumours expressed chromogranin A (CgA), somatostatin receptor type 2 and vascular endothelial growth factor-A. Serum CgA concentrations in Men1 +/− mice were not elevated. Adrenocortical tumours, which immunostained for 3-β-hydroxysteroid dehydrogenase, developed in seven Men1 +/− mice, but resulted in hypercorticosteronaemia in one out of the four mice that were investigated. Thus, these Men1 +/− mice are representative of MEN1 in man, and will help in investigating molecular mechanisms and treatments for endocrine tumours.
Michaela Luconi, Monica Mangoni, Stefania Gelmini, Giada Poli, Gabriella Nesi, Michela Francalanci, Nicola Pratesi, Giulia Cantini, Adriana Lombardi, Monica Pepi, Tonino Ercolino, Mario Serio, Claudio Orlando, and Massimo Mannelli
Adrenocortical carcinoma (ACC) is a rare aggressive tumor with a poor prognosis. The lack of a specific and effective medical treatment is due to the poor knowledge of the mechanisms underlying tumor growth. Research on potential drugs able to specifically interfere with tumor proliferation is essential to develop more efficacious therapies. We evaluated for the first time the in vivo effect of rosiglitazone (RGZ), an anti-diabetic drug with in vitro anti-tumor properties, on ACC proliferation in a xenograft model obtained by s.c. injection of human ACC H295R cells in athymic mice. When the tumor size reached 5 mm, animals were allocated to 5 mg/kg RGZ- or water-treated groups. Tumor volume was measured twice a week. A significant reduction of tumor growth in RGZ versus control (control) group was observed and was already maximal following 17 day treatment (1−T/C=75.4% (43.7–93.8%)). After 31 days of treatment, mice were killed and tumor analyzed. Tumor histological evaluation revealed characteristics of invasiveness, richness in small vessels and mitotic figures in control group, while RGZ group tumors presented non infiltrating borders, few vessels, and many apoptotic bodies. Tumor immunohistochemistry showed that Ki-67 was reduced in RGZ versus control group. Quantitative real-time RT-PCR demonstrated a significant reduction in the expression of angiogenic (VEGF), vascular (CD31), proliferation (BMI-1), and anti-apoptotic (Bcl-2) genes in RGZ versus control group tumors. The same inhibitory effects were confirmed in in vitro RGZ-treated H295R. Our findings support and expand the role of RGZ in controlling ACC proliferation and angiogenesis in vivo and in vitro.
David J Gross, Gabriel Munter, Menachem Bitan, Tali Siegal, Alberto Gabizon, Ronny Weitzen, Ofer Merimsky, Aliza Ackerstein, Asher Salmon, Avishai Sella, and Shimon Slavin
Group-author : The Israel Glivec in Solid Tumors Study Group
Imatinib mesylate (IM), a small molecule that is a selective inhibitor of the ABL, platelet derived growth factor receptor (PDGFR-R) and stem cell ligand receptor (c-kit) tyrosine kinases (TK). IM was also found to inhibit the TK activity of BCR/ABL fusion protein produced in chronic myelogenous leukemia, with marked clinical activity against the disease. Since both PDGF-R and c-kit both having a putative role in tumorigenesis, we investigated the efficacy and safety of the use of IM in patients with endocrine tumors unresponsive to conventional therapies that expressed c-kit and/or PDGF-R (within the framework of a comprehensive phase II multi-center study of IM in patients with solid tumors). IM was initiated at a dose of 400 mg/day, with possible dose escalation within 1 week to 600 mg/day and an option to raise the dose to 800 mg/day in the event of progression and in the absence of safety concerns for a period of up to 12 months. Between September 2002 and July 2003, 15 adult patients with disseminated endocrine tumors were recruited as follows: medullary thyroid carcinoma (MTC, n = 6); adrenocortical carcinoma (ACC, n = 4); malignant pheochromocytoma (pheo, n = 2); carcinoid (non-secreting, n = 2), neuroendocrine tumor (NET, n = 1). No objective responses were observed. MTC – disease progression in 4 patients, and treatment discontinuation in 2 patients due to adverse events; ACC – disease progression in 3 patients, and treatment discontinuation in 1 patient due to severe psychiatric adverse event; Pheo – disease progression in 2 patients; Carcinoid – stable disease in 1 patient (6.5 months), and disease progression in 1 patient; NET – disease progression in 1 patient. IM does not appear to be useful for treatment of malignant endocrine tumors, also causing significant toxicity in this patient population.
Nunki Hassan, Jing Ting Zhao, Anthony Glover, Bruce G Robinson, and Stan B Sidhu
Adrenocortical carcinoma (ACC) has high recurrence rates and poor prognosis with limited response to conventional cancer therapy. Recent contributions of high-throughput transcriptomic profiling identified microRNA-497 (miR-497) as significantly underexpressed, while lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) as overexpressed in ACC. miR-497 is located in the chromosomal region 17p13.1, in which there is a high frequency of loss of heterozygosity in ACC. We aim to investigate the interaction of miR-497 and MALAT1 in ACC and its functional roles in the process of tumourigenesis. In this study, we demonstrated miR-497 post-transcriptionally repressed MALAT1 while MALAT1 also competes for miR-497 binding to its molecular target, EIF4E (eukaryotic translation initiation factor 4E). We showed that overexpression of miR-497 and silencing of MALAT1 suppressed cellular proliferation and induced cell cycle arrest through downregulation of EIF4E expression. Furthermore, MALAT1 directly binds to SFPQ (splicing factor proline and glutamine rich) protein, indicating its multifaceted roles in ACC pathophysiology. This is the first study to identify the feedback axis of miR-497-MALAT1/EIF4E in ACC tumourigenesis, providing novel insights into the molecular functions of noncoding RNAs in ACC.
Roland Pfoh, Ira Kay Lacdao, and Vivian Saridakis
Deubiquitinases (DUBs) play important roles and therefore are potential drug targets in various diseases including cancer and neurodegeneration. In this review, we recapitulate structure–function studies of the most studied DUBs including USP7, USP22, CYLD, UCHL1, BAP1, A20, as well as ataxin 3 and connect them to regulatory mechanisms and their growing protein interaction networks. We then describe DUBs that have been associated with endocrine carcinogenesis with a focus on prostate, ovarian, and thyroid cancer, pheochromocytoma, and adrenocortical carcinoma. The goal is enhancing our understanding of the connection between dysregulated DUBs and cancer to permit the design of therapeutics and to establish biomarkers that could be used in diagnosis and prognosis.