TERT promoter mutations are emerging prognostic biomarkers in multiple cancers and are found in highly aggressive thyroid cancer. Our aim is to investigate the prognostic value of these mutations for the outcome of thyroid cancer-related mortality in a large cohort of thyroid cancer patients. This was a retrospective study of 409 patients (393 with differentiated thyroid cancer) with a median age of 44 years (range 16–81 years) and median follow-up of 13 years (interquartile range 11–16 years). Analyses of associations between mutational status and various clinicopathological variables were performed. TERT promoter mutations were identified in 32 (9.8%) papillary, 11 (16.7%) follicular and seven (43.8%) poorly differentiated/anaplastic thyroid cancer patients. The presence of TERT promoter mutations was associated with factors such as increased age (P < 0.001), extrathyroidal invasion (P = 0.01), increased stage at diagnosis (P < 0.001) and dedifferentiated histological type (P = 0.001). A TERT promoter mutation was independently associated with poorer overall survival in patients with differentiated thyroid cancer (10-year survival rate, 66.2% vs 98.3% for wild type; adjusted HR, 7.18; 95% CI: 2.77–18.59) and in patients with papillary cancer (74.2% vs 99.3%; 14.20; 3.03–66.68). Concomitant TERT and BRAF mutations worsened the survival rate of patients with papillary cancer (82.6% vs 99.4% for exclusively BRAF mutation alone; 5.62; 1.85–17.09). In conclusion, the presence of TERT promoter mutations is independently associated with increased mortality in patients with differentiated thyroid cancer. The results suggest that inclusion of TERT promoter mutation analysis with conventional clinicopathological evaluation can lead to better prognostication and management for individual patients.
Tae Hyuk Kim, Young-Eun Kim, Soomin Ahn, Ji-Youn Kim, Chang-Seok Ki, Young Lyun Oh, Kyunga Kim, Jae Won Yun, Woong-Yang Park, Jun-Ho Choe, Jung-Han Kim, Jee Soo Kim, Sun Wook Kim, and Jae Hoon Chung
Alessandro Antonelli, Silvia Martina Ferrari, Poupak Fallahi, Silvia Frascerra, Simona Piaggi, Stefania Gelmini, Cristiana Lupi, Michele Minuto, Piero Berti, Salvatore Benvenga, Fulvio Basolo, Claudio Orlando, and Paolo Miccoli
In papillary thyroid carcinomas (PTCs), oncogenes activate a transcriptional program including the upregulation of CXCL10 chemokine, which stimulates proliferation and invasion. Furthermore, peroxisome proliferator-activated receptor-γ (PPARγ) activators thiazolidinediones (TZDs) modulate CXCL10 secretion in normal thyroid follicular cells (TFC), and inhibit PTC growth. Until now, no study has evaluated the effect of cytokines on CXCL10 secretion in PTCs, nor the effect of PPARγ activation. The combined effects of interferon γ (IFNγ) and tumor necrosis factor α (TNFα) stimulation on CXCL10 secretion in primary cells from PTCs and TFC were tested. Furthermore, the effect of PPARγ activation by TZDs, on CXCL10 secretion and proliferation in these cell types was studied. In primary cultures of TFC and PTCs CXCL10 production was absent under basal conditions; a similar dose-dependent secretion of CXCL10 was induced by IFNγ in both cell types. TNFα alone induced a slight but significant CXCL10 secretion only in PTCs. The stimulation with IFNγ+TNFα induced a synergistic CXCL10 release in both cell types; however, a secretion more than ten times higher was induced in PTCs. Treatment of TFC with TZDs dose-dependently suppressed IFNγ+TNFα-induced CXCL10 release, while TZDs stimulated CXCL10 secretion in PTCs. A significant antiproliferative effect by TZDs was observed only in PTCs. In conclusion, a dysregulation of CXCL10 secretion has been shown in PTCs. In fact, a CXCL10 secretion more than ten times higher has been induced by IFNγ+TNFα in PTCs with respect to TFC. Moreover, TZDs inhibited CXCL10 secretion in TFC and stimulated it in PTCs. The effect of TZDs on CXCL10 was unrelated to the significant antiproliferative effect in PTCs.
Muhammad Yasir Asghar, Tero Viitanen, Kati Kemppainen, and Kid Törnquist
Anaplastic thyroid cancer (ATC) is the most aggressive form of human thyroid cancer, lacking any effective treatment. Sphingosine 1-phosphate (S1P) receptors and human ether-a′-go-go-related gene (HERG (KCNH2)) potassium channels are important modulators of cell migration. In this study, we have shown that the S1P1–3 receptors are expressed in C643 and THJ-16T human ATC cell lines, both at mRNA and protein level. S1P inhibited migration of these cells and of follicular FTC-133 thyroid cancer cells. Using the S1P1,3 inhibitor VPC-23019, the S1P2 inhibitor JTE-013, and the S1P2 receptor siRNA, we showed that the effect was mediated through S1P2. Treatment of the cells with the Rho inhibitor C3 transferase abolished the effect of S1P on migration. S1P attenuated Rac activity, and inhibiting Rac decreased migration. Sphingosine kinase inhibitor enhanced basal migration of cells, and addition of exogenous S1P inhibited migration. C643 cells expressed a nonconducting HERG protein, and S1P decreased HERG protein expression. The HERG blocker E-4031 decreased migration. Interestingly, downregulating HERG protein with siRNA decreased the basal migration. In experiments using HEK cells overexpressing HERG, we showed that S1P decreased channel protein expression and current and that S1P attenuated migration of the cells. We conclude that S1P attenuates migration of C643 ATC cells by activating S1P2 and the Rho pathway. The attenuated migration is also, in part, dependent on a S1P-induced decrease of HERG protein.
Kensey Bergdorf, Donna C Ferguson, Mitra Mehrad, Kim Ely, Thomas Stricker, and Vivian L Weiss
The prevalence of thyroid carcinoma is increasing and represents the most common endocrine malignancy, with papillary thyroid carcinoma (PTC) being the most frequent subtype. The genetic alterations identified in PTCs fail to distinguish tumors with different clinical behaviors, such as extra-thyroidal extension and lymph node metastasis. We hypothesize that the immune microenvironment may play a critical role in tumor invasion and metastasis. Computational immunogenomic analysis was performed on 568 PTC samples in The Cancer Genome Atlas using CIBERSORT, TIMER and TIDE deconvolution analytic tools for characterizing immune cell composition. Immune cell infiltrates were correlated with histologic type, mutational type, tumor pathologic T stage and lymph node N stage. Dendritic cells (DCs) are highly associated with more locally advanced tumor T stage (T3/T4, odds ratio (OR) = 2.6, CI = 1.4–4.5, P = 5.4 × 10−4). Increased dendritic cells (OR = 3.4, CI = 1.9–6.3, P = 5.5 × 10−5) and neutrophils (OR = 10.5, CI = 2.7–44, P = 8.7 × 10−4) significantly correlate with lymph node metastasis. In addition, dendritic cells positively correlate with tall cell morphology (OR = 4.5, CI = 1.6–13, P = 4.9 × 10−3) and neutrophils negatively correlate with follicular morphology (OR = 1.3 × 10−3, CI = 5.3 × 10−5–0.031, P = 4.1 × 10−5). TIDE analysis indicates an immune-exclusive phenotype that may be mediated by increased galectin-3 found in PTCs. Thus, characterization of the PTC immune microenvironment using three computational platforms shows that specific immune cells correlate with mutational type, histologic type, local tumor extent and lymph node metastasis. Immunologic evaluation of PTCs may provide a better indication of biologic behavior, resulting in the improved diagnosis and treatment of thyroid cancer.
Xiulong Xu, Helen Ding, Geetha Rao, Shalini Arora, Constantine P Saclarides, Joseph Esparaz, Paolo Gattuso, Carmen C Solorzano, and Richard A Prinz
The sonic hedgehog (SHH) pathway is activated in several types of malignancy and plays an important role in tumor cell proliferation and tumorigenesis. SHH binding to a 12-pass transmembrane receptor, Patched (PTCH), leads to freeing of Smoothened (SMO) and subsequent activation of GLI transcription factors. In the present study, we analyzed the expression of SHH, PTCH, SMO, and GLI1 in 31 follicular thyroid adenomas (FTA), 8 anaplastic thyroid carcinomas (ATC), and 51 papillary thyroid carcinomas (PTC) by immunohistochemical staining. More than 65% of FTA, PTC, and ATC specimens stained positive for SHH, PTCH, SMO, and GLI. However, the expression of the genes encoding these four molecules did not correlate with any clinicopathologic parameters, including the age, gender, the status of BRAF gene mutation, tumor stage, local invasion, and metastasis. Three thyroid tumor cell lines (KAT-18, WRO82, and SW1736) all expressed the genes encoding these four molecules. 5-Bromo-2-deoxyuridine labeling and MTT cell proliferation assays revealed that cyclopamine (CP), an inhibitor of the SHH pathway, was able to inhibit the proliferation of KAT-18 and WRO82 cells more effectively than SW1736 cells. CP led to the arrest of cell cycle or apoptosis. Knockdown of SHH and GLI expression by miRNA constructs that target SHH or GLI mRNA in KAT-18 and SW1736 cells led to the inhibition of cell proliferation. Our results suggest that the SHH pathway is widely activated in thyroid neoplasms and may have potential as an early marker of thyroid cancer or as a potential therapeutic target for thyroid cancer treatment.
Garcilaso Riesco-Eizaguirre and Pilar Santisteban
Well-differentiated thyroid cancer has in general terms a very good outcome. It has a very slow growth rate and, although it metastasises at a relatively high frequency, it has very high survival rates. Whereas the prevalence of nodular thyroid disease worldwide is high, malignant conversion from benign thyroid nodules is rare. Treatment of thyroid cancer is usually successful, but we still do not have effective therapies for patients with invasive or metastatic thyroid cancer if the disease does not concentrate radioiodine and it is not surgically resectable. On the other hand, from the same thyroid cell, one of the most aggressive human tumours can arise – undifferentiated or anaplastic thyroid carcinoma – leading to death in a few months. What features of this malignancy account for such paradoxical behaviour? The most common type of thyroid cancer – papillary thyroid carcinoma – stands out among solid tumours because many of the tumour-initiating events have been identified. All of them function in a single pathway – the RTK/RAS/RAF/MAPK pathway – and obey an ‘exclusivity principle’: one and only one component of the pathway is mutated in a single tumour. This highlights the requirement of this signal transduction pathway for the transformation to thyroid cancer and paves the way to targeted therapies against a tumour with a mutation in a known gene or any gene upstream of the target. However, it is also interesting to underscore the differences among the tumours arising from the different mutations. Studies in vitro and in vivo, including genomic profiling and genetically engineered mouse models, have clearly shown that each oncoprotein exerts its own oncogenic drive, conferring a distinct biological behaviour on thyroid tumours. In this review, we attempt to summarise the most recent advances in thyroid follicular cell-derived cancers research and their potential clinical impact that may change the management of thyroid cancer in the near future.
Margarida M Moura, Branca M Cavaco, and Valeriano Leite
Medullary thyroid carcinoma (MTC) is a rare malignancy originating from the calcitonin-secreting parafollicular thyroid C cells. Approximately 75% of cases are sporadic. Rearranged during transfection (RET) proto-oncogene plays a crucial role in MTC development. Besides RET, other oncogenes commonly involved in the pathogenesis of human cancers have also been investigated in MTC. The family of human RAS genes includes the highly homologous HRAS, KRAS, and NRAS genes that encode three distinct proteins. Activating mutations in specific hotspots of the RAS genes are found in about 30% of all human cancers. In thyroid neoplasias, RAS gene point mutations, mainly in NRAS, are detected in benign and malignant tumors arising from the follicular epithelium. However, recent reports have also described RAS mutations in MTC, namely in HRAS and KRAS. Overall, the prevalence of RAS mutations in sporadic MTC varies between 0–43.3%, occurring usually in tumors with WT RET and rarely in those harboring a RET mutation, suggesting that activation of these proto-oncogenes represents alternative genetic events in sporadic MTC tumorigenesis. Thus, the assessment of RAS mutation status can be useful to define therapeutic strategies in RET WT MTC. MTC patients with RAS mutations have an intermediate risk for aggressive cancer, between those with RET mutations in exons 15 and 16, which are associated with the worst prognosis, and cases with other RET mutations, which have the most indolent course of the disease. Recent results from exome sequencing indicate that, besides mutations in RET, HRAS, and KRAS, no other recurrent driver mutations are present in MTC.
J Lado-Abeal, R Celestino, S B Bravo, M E R Garcia-Rendueles, J de la Calzada, I Castro, P Castro, C Espadinha, F Palos, P Soares, C V Alvarez, M Sobrinho-Simões, and J Cameselle-Teijeiro
Our main objective was to search for mutations in candidate genes and for paired box gene 8–peroxisome proliferator-activated receptor gamma (PAX8–PPARγ) rearrangement in a well-differentiated angioinvasive follicular thyroid carcinoma (FTC) causing hyperthyroidism. DNA and RNA were extracted from the patient's thyroid tumor, as well as ‘normal’ thyroid tissue, and from peripheral blood lymphocytes (PBLs) of the patient, her daughter, and two siblings. Nuclear isolation was extracted from the patient's tumor, ’normal’ thyroid tissue, PBLs, and uterine leiomyoma tissue. TSH receptor (TSHR), RAS, and BRAF genes were sequenced. We searched for PAX8 – PPAR γ in thyroid, PBL, and uterine leiomyoma samples from the patient and family members. Proliferative effects of detected mutants on non-transformed human thyrocytes cultures. An activating TSHR mutation, M453T, was detected in the tumor. PAX8 (exons 1 – 8 + 10)– PPAR γ was found in all tested patient's tissues. A second rearrangement, PAX8 (exons 1 – 8)– PPAR γ, was detected in the patient's normal thyroid tissue. Under deprived medium condition, co-transfection of PAX8 – PPAR γ and TSHR – M453T dramatically increased the number of thyrocytes, an effect that it was not observed with TSHR wild-type (WT); under complete medium conditions, co-transfection of PAX8 – PPAR γ with either TSHR – M453T or TSHR – WT inhibited cell proliferation. We report a patient with hyperthyroidism due to a FTC bearing an activating TSHR mutation and PAX8 – PPAR γ rearrangements. PAX8 – PPAR γ was present as a mosaicism affecting tissues from endodermal and mesodermal origin. PAX8 – PPAR γ and TSHR – M453T inhibited or promoted thyrocyte proliferation depending on medium conditions. The activating TSHR mutation could promote in vivo FTC development in PAX8 – PPAR γ-positive thyrocytes under poor blood supply with deprivation of growth factors but restraint the tumor growth when growth factors are supplied.
Zhaoxia Zhang, Sasha Beyer, and Sissy M Jhiang
The Na+/I− symporter (NIS (SLC5A5)) is a transmembrane glycoprotein that mediates active iodide uptake into thyroid follicular cells. NIS-mediated iodide uptake in thyroid cells is the basis for targeted radionuclide imaging and treatment of differentiated thyroid carcinomas and their metastases. Furthermore, NIS is expressed in many human breast tumors but not in normal non-lactating breast tissue, suggesting that NIS-mediated radionuclide uptake may also allow the imaging and targeted therapy of breast cancer. However, functional cell surface NIS expression is often low in breast cancer, making it important to uncover signaling pathways that modulate NIS expression at multiple levels, from gene transcription to posttranslational processing and cell surface trafficking. In this study, we investigated NIS regulation in breast cancer by MAPK/extracellular signal-regulated kinase (ERK) kinase (MEK) signaling, an important cell signaling pathway involved in oncogenic transformation. We found that MEK inhibition decreased NIS protein levels in all-trans retinoic acid/hydrocortisone-treated MCF-7 cells as well as human breast cancer cells expressing exogenous NIS. The decrease in NIS protein levels by MEK inhibition was not accompanied by a decrease in NIS mRNA or a decrease in NIS mRNA export from the nucleus to the cytoplasm. NIS protein degradation upon MEK inhibition was prevented by lysosome inhibitors but not by proteasome inhibitors. Interestingly, NIS protein level was correlated with MEK/ERK activation in human breast tumors from a tissue microarray. Taken together, MEK activation appears to play an important role in maintaining NIS protein stability in human breast cancers.
Iñigo Landa, Cristina Montero-Conde, Donatella Malanga, Silvia De Gisi, Guillermo Pita, Luis-Javier Leandro-García, Lucía Inglada-Pérez, Rocío Letón, Carmela De Marco, Cristina Rodríguez-Antona, Giuseppe Viglietto, and Mercedes Robledo
The aim of this study is to assess if common genetic variants located in the CDKN1B locus, coding for the cell cycle inhibitor p27Kip1, are involved in thyroid cancer susceptibility. Based on the literature and functional predictions, we selected three polymorphisms within the CDKN1B gene (rs2066827 (T326G, V109G), rs34330 (−79C>T) and rs36228499 (−838C>A)) to perform the first case–control study in thyroid cancer involving this locus. We had 649 Spanish patients with sporadic thyroid cancer and 385 healthy representative controls available. Luciferase reporter gene assays, real-time quantitative reverse transcription-PCR and immunoblot experiments were carried out to demonstrate the putative effect of the associated variant. The polymorphism rs34330 (−79C>T) was identified as a risk factor for developing the follicular variant of papillary thyroid carcinoma (FVPTC), fitting a recessive model (odds ratio=2.12; 95% confidence interval=1.09–4.15; P value=0.023). The risk allele (T) of this single nucleotide polymorphism led to a lower transcription rate in cells transfected with a luciferase reporter driven by the polymorphic p27Kip1 promoter (P value <0.001). This effect was observed in −79TT genotype control carriers, who showed a tendency towards lower CDKN1B mRNA levels in lymphocytes, as well as at the protein level. This is the first study that identifies CDKN1B as a low-penetrance gene in thyroid cancer, and specifically in FVPTC subtype. We propose a reduced CDKN1B gene transcription depending on the genotype of the −79C>T (rs34330) variant as a novel mechanism underlying p27Kip1 downregulation.