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Open access

Jonathan M Fussey, Robin N Beaumont, Andrew R Wood, Bijay Vaidya, Joel Smith, and Jessica Tyrrell

Evidence from observational studies suggest a positive association between serum thyroid-stimulating hormone (TSH) levels and differentiated thyroid carcinoma. However, the cause–effect relationship is poorly understood and these studies are susceptible to bias and confounding. This study aimed to investigate the causal role of TSH in both benign thyroid nodules and thyroid cancer in up to 451,025 UK Biobank participants, using a genetic technique, known as Mendelian randomization (MR). Hospital Episode Statistics and Cancer Registry databases were used to identify 462 patients with differentiated thyroid carcinoma and 2031 patients with benign nodular thyroid disease. MR methods using genetic variants associated with serum TSH were used to test causal relationships between TSH and the two disease outcomes. Mendelian randomization provided evidence of a causal link between TSH and both thyroid cancer and benign nodular thyroid disease. Two-sample MR suggested that a 1 s.d. higher genetically instrumented TSH (approximately 0.8 mIU/L) resulted in 4.96-fold higher odds of benign nodular disease (95% CI 2.46–9.99) and 2.00-fold higher odds of thyroid cancer (95% CI 1.09–3.70). Our results thus support a causal role for TSH in both benign nodular thyroid disease and thyroid cancer.

Open access

Peipei Xu, Su Zeng, Xiaotian Xia, Ziheng Ye, Meifang Li, Mingyun Chen, Tian Xia, Jingjing Xu, Qiong Jiao, Liang Liu, Lianxi Li, and Minggao Guo

Our aims were to uncover the role of Family with sequence similarity 172-member A (FAM172A) in pathogenesis of follicular thyroid carcinoma (FTC) and to evaluate its value in differential diagnosis between malignant and benign thyroid follicular lesions. FAM172A expression was evaluated by q-PCR, immunoblotting and immunohistochemistry (IHC). The ability of proliferation, migration and invasion of cells were assessed by Cell Counting Kit-8 assay (CCK8), Clone-formation and Transwell assays. Nude mouse tumorigenicity assays were used to investigate the role of FAM172A in pathogenesis of FTC in vivo. The value of FAM172A in differential diagnosis for FTC were assessed using 120 formalin-fixed paraffin-embedded (FFPE) tissues after operation and 81 fine-needle aspiration biopsy (FNAB) samples before operation. FAM172A was highly expressed in FTC tissues and FTC cell lines. Down-regulation of FAM172A inhibited the proliferation, invasion and migration of FTC cells through Erk1/2 and JNK pathways. Subcutaneous tumorigenesis in nude mice showed that knockdown of FAM172A inhibited tumor growth and progression in vivo. The FAM172A IHC scores of 3.5 had 92% sensitivity and 63% specificity to separate FTC from benign/borderline thyroid follicular lesions, and 92% sensitivity and 80% specificity to discriminate FTC from benign thyroid follicular lesions in postoperative FFPE samples. The corresponding values were 75% and 78%, and 75% and 89% in preoperative FNA samples, respectively. FAM172A plays an important role in the pathogenesis of FTC through Erk1/2 and JNK pathways. FAM172A may be a potential marker for preoperative diagnosis of FTC based on the IHC results of thyroid FNAB samples.

Open access

Andreas M Hoff, Sigrid M Kraggerud, Sharmini Alagaratnam, Kaja C G Berg, Bjarne Johannessen, Maren Høland, Gro Nilsen, Ole C Lingjærde, Peter W Andrews, Ragnhild A Lothe, and Rolf I Skotheim

Testicular germ cell tumours (TGCTs) appear as different histological subtypes or mixtures of these. They show similar, multiple DNA copy number changes, where gain of 12p is pathognomonic. However, few high-resolution analyses have been performed and focal DNA copy number changes with corresponding candidate target genes remain poorly described for individual subtypes. We present the first high-resolution DNA copy number aberration (CNA) analysis on the subtype embryonal carcinomas (ECs), including 13 primary ECs and 5 EC cell lines. We identified recurrent gains and losses and allele-specific CNAs. Within these regions, we nominate 30 genes that may be of interest to the EC subtype. By in silico analysis of data from 150 TGCTs from The Cancer Genome Atlas (TCGA), we further investigated CNAs, RNA expression, somatic mutations and fusion transcripts of these genes. Among primary ECs, ploidy ranged between 2.3 and 5.0, and the most common aberrations were DNA copy number gains at chromosome (arm) 7, 8, 12p, and 17, losses at 4, 10, 11, and 18, replicating known TGCT genome characteristics. Gain of whole or parts of 12p was found in all samples, including a highly amplified 100 kbp segment at 12p13.31, containing SLC2A3. Gain at 7p21, encompassing ETV1, was the second most frequent aberration. In conclusion, we present novel CNAs and the genes located within these regions, where the copy number gain of SLC2A3 and ETV1 are of interest, and which copy number levels also correlate with expression in TGCTs.

Open access

Xiyuan Zhang, Fabia de Oliveira Andrade, Hansheng Zhang, Idalia Cruz, Robert Clarke, Pankaj Gaur, Vivek Verma, and Leena Hilakivi-Clarke

Over 50% of women at a childbearing age in the United States are overweight or obese, and this can adversely affect their offspring. We studied if maternal obesity-inducing high fat diet (HFD) not only increases offspring’s mammary cancer risk but also impairs response to antiestrogen tamoxifen. Female rat offspring of HFD and control diet-fed dams, in which estrogen receptor-positive (ER+) mammary tumors were induced with the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA), exhibited similar initial responses to antiestrogen tamoxifen. However, after tamoxifen therapy was completed, almost all (91%) tumors recurred in HFD offspring, compared with only 29% in control offspring. The increase in local mammary tumor recurrence in HFD offspring was linked to an increase in the markers of immunosuppression (Il17f, Tgfβ1, VEGFR2) in the tumor microenvironment (TME). Protein and mRNA levels of the major histocompatibility complex II (MHC-II), but not MHC-I, were reduced in the recurring DMBA tumors of HFD offspring. Further, infiltration of CD8+ effector T cells and granzyme B+ (GZMB+) cells were lower in their recurring tumors. To determine if maternal HFD can pre-program similar changes in the TME of allografted E0771 mammary tumors in offspring of syngeneic mice, flow cytometry analysis was performed. E0771 mammary tumor growth was significantly accelerated in the HFD offspring, and a reduction in the numbers of GZMB and non-significant reduction of interferon γ (IFNγ) secreting CD8+ T cells in the TME was seen. Thus, consumption of a HFD during pregnancy increases susceptibility of the female rat and mouse offspring to tumor immune suppression and mammary tumor growth and recurrence.

Open access

Estefania Labanca, Elba S Vazquez, Paul G Corn, Justin M Roberts, Fen Wang, Christopher J Logothetis, and Nora M Navone

Many solid tumors metastasize to bone, but only prostate cancer has bone as a single, dominant metastatic site. Recently, the FGF axis has been implicated in cancer progression in some tumors and mounting evidence indicate that it mediates prostate cancer bone metastases. The FGF axis has an important role in bone biology and mediates cell-to-cell communication. Therefore, we discuss here basic concepts of bone biology, FGF signaling axis, and FGF axis function in adult bone, to integrate these concepts in our current understanding of the role of FGF axis in bone metastases.

Open access

Kate M Warde, Erik Schoenmakers, Eduardo Ribes Martinez, Yi Jan Lim, Maeve Leonard, Sarah J Lawless, Paula O’Shea, Krishna V Chatterjee, Mark Gurnell, Constanze Hantel, and Michael Conall Dennedy

Adrenocortical carcinoma (ACC) is a rare aggressive malignancy with a poor outcome largely due to limited treatment options. Here, we propose a novel therapeutic approach through modulating intracellular free cholesterol via the liver X receptor alpha (LXRα) in combination with current first-line pharmacotherapy, mitotane. H295R and MUC-1 ACC cell lines were pretreated with LXRα inhibitors in combination with mitotane. In H295R, mitotane (20, 40 and 50 µM) induced dose-dependent cell death; however, in MUC-1, this only occurred at a supratherapeutic concentration (200 µM). LXRα inhibition potentiated mitotane-induced cytotoxicity in both cell lines. This was confirmed through use of the CompuSyn model which showed moderate pharmacological synergism and was indicative of apoptotic cell death via an increase in annexinV and cleaved-caspase 3 expression. Inhibition of LXRα was confirmed through downregulation of cholesterol efflux pumps ABCA1 and ABCG1; however, combination treatment with mitotane attenuated this effect. Intracellular free-cholesterol levels were associated with increased cytotoxicity in H295R (r 2 = 0.5210) and MUC-1 (r 2 = 0.9299) cells. While both cell lines exhibited similar levels of free cholesterol at baseline, H295R were cholesterol ester rich, whereas MUC-1 were cholesterol ester poor. We highlight the importance of LXRα mediated cholesterol metabolism in the management of ACC, drawing attention to its role in the therapeutics of mitotane sensitive tumours. We also demonstrate significant differences in cholesterol storage between mitotane sensitive and resistant disease.

Open access

James F Powers, Brent Cochran, James D Baleja, Hadley D Sikes, Andrew D Pattison, Xue Zhang, Inna Lomakin, Annette Shepard-Barry, Karel Pacak, Sun Jin Moon, Troy F Langford, Kassi Taylor Stein, Richard W Tothill, Yingbin Ouyang, and Arthur S Tischler

Tumors caused by loss-of-function mutations in genes encoding TCA cycle enzymes have been recently discovered and are now of great interest. Mutations in succinate dehydrogenase (SDH) subunits cause pheochromocytoma/paraganglioma (PCPG) and syndromically associated tumors, which differ phenotypically and clinically from more common SDH-intact tumors of the same types. Consequences of SDH deficiency include rewired metabolism, pseudohypoxic signaling and altered redox balance. PCPG with SDHB mutations are particularly aggressive, and development of treatments has been hampered by lack of valid experimental models. Attempts to develop mouse models have been unsuccessful. Using a new strategy, we developed a xenograft and cell line model of SDH-deficient pheochromocytoma from rats with a heterozygous germline Sdhb mutation. The genome, transcriptome and metabolome of this model, called RS0, closely resemble those of SDHB-mutated human PCPGs, making it the most valid model now available. Strategies employed to develop RS0 may be broadly applicable to other SDH-deficient tumors.

Open access

Johan O Paulsson, Na Wang, Jiwei Gao, Adam Stenman, Jan Zedenius, Ninni Mu, Weng-Onn Lui, Catharina Larsson, and C Christofer Juhlin

Mutations in the miRNA enzyme gene DICER1 have been reported in several endocrine malignancies and is associated with the rare tumour-predisposing DICER1 syndrome. DICER1 mutations have been reported in subsets of follicular thyroid carcinoma (FTC), but the role of DICER1 in follicular thyroid tumorigenesis has not been extensively studied. In this study, we investigate the role of DICER1 in 168 follicular thyroid tumours and in an FTC cell line. We found rare DICER1 mutations in paediatric FTC cases and a general DICER1 down-regulation in FTCs visualized both on mRNA and protein level, especially pronounced in Hürthle cell carcinoma (HuCC). The down-regulation was also evident in follicular thyroid adenomas (FTAs), suggesting a potential early step in tumorigenesis. The expression of DICER1 was lower in FTCs of older patients in which TERT promoter mutations are more frequent. In FTCs, DICER1 down-regulation was not caused by gene copy number loss but significantly correlated to expression of the transcription factor GABPA in clinical cases. GABPA was found to bind to the DICER1 promoter and regulate DICER1 expression in vitro, as GABPA depletion in FTC cell lines reduced DICER1 expression. This in turn stimulated cell proliferation and affected the miRNA machinery, evident by altered miRNA expression. To conclude, we show that GABPA directly regulates DICER1 in FTC, acting as a tumour suppressor and displaying down-regulation in clinical samples. We also show reduced expression of DICER1 in benign and malignant follicular thyroid tumours, suggesting a potentially early tumorigenic role of this gene aberrancy.

Open access

Emanuel Christ, Kwadwo Antwi, Melpomeni Fani, and Damian Wild

Receptors for the incretin glucagon-like peptide-1 (GLP-1R) have been found overexpressed in selected types of human tumors and may, therefore, play an increasingly important role in endocrine gastrointestinal tumor management. In particular, virtually all benign insulinomas express GLP-1R in high density. Targeting GLP-1R with indium-111, technetium-99m or gallium-68-labeled exendin-4 offers a new approach that permits the successful localization of small benign insulinomas. It is likely that this new non-invasive technique has the potential to replace the invasive localization of insulinomas by selective arterial stimulation and venous sampling. In contrast to benign insulinomas, malignant insulin-secreting neuroendocrine tumors express GLP-1R in only one-third of the cases, while they more often express the somatostatin subtype 2 receptors. Importantly, one of the two receptors appears to be always overexpressed. In special cases of endogenous hyperinsulinemic hypoglycemia (EHH), that is, in the context of MEN-1 or adult nesidioblastosis GLP-1R imaging is useful whereas in postprandial hypoglycemia in the context of bariatric surgery, GLP-1R imaging is probably not helpful. This review focuses on the potential use of GLP-1R imaging in the differential diagnosis of EHH.

Open access

K E Lines, P Filippakopoulos, M Stevenson, S Müller, H E Lockstone, B Wright, S Knapp, D Buck, C Bountra, and R V Thakker

Medical treatments for corticotrophinomas are limited, and we therefore investigated the effects of epigenetic modulators, a new class of anti-tumour drugs, on the murine adrenocorticotropic hormone (ACTH)-secreting corticotrophinoma cell line AtT20. We found that AtT20 cells express members of the bromo and extra-terminal (BET) protein family, which bind acetylated histones, and therefore, studied the anti-proliferative and pro-apoptotic effects of two BET inhibitors, referred to as (+)-JQ1 (JQ1) and PFI-1, using CellTiter Blue and Caspase Glo assays, respectively. JQ1 and PFI-1 significantly decreased proliferation by 95% (P < 0.0005) and 43% (P < 0.0005), respectively, but only JQ1 significantly increased apoptosis by >50-fold (P < 0.0005), when compared to untreated control cells. The anti-proliferative effects of JQ1 and PFI-1 remained for 96 h after removal of the respective compound. JQ1, but not PFI-1, affected the cell cycle, as assessed by propidium iodide staining and flow cytometry, and resulted in a higher number of AtT20 cells in the sub G1 phase. RNA-sequence analysis, which was confirmed by qRT-PCR and Western blot analyses, revealed that JQ1 treatment significantly altered expression of genes involved in apoptosis, such as NFκB, and the somatostatin receptor 2 (SSTR2) anti-proliferative signalling pathway, including SSTR2. JQ1 treatment also significantly reduced transcription and protein expression of the ACTH precursor pro-opiomelanocortin (POMC) and ACTH secretion by AtT20 cells. Thus, JQ1 treatment has anti-proliferative and pro-apoptotic effects on AtT20 cells and reduces ACTH secretion, thereby indicating that BET inhibition may provide a novel approach for treatment of corticotrophinomas.