Reduced expression of THRβ in papillary thyroid carcinomas: relationship with BRAF mutation, aggressiveness and miR expression

Effective TRIAC treatment of a THRβ-mutated patient with thyroid hormone resistance

Resistance to thyroid hormone (RTH) is a rare autosomal dominant disease characterized by an alteration of thyroid hormone negative feedback, usually as a consequence of a mutation in the thyroid hormone receptor-b gene (THRβ). It is characterized by high variability of clinical manifestations, ranging from isolated abnormal thyroid function tests without symptoms to severe and impaired clinical conditions. Here we report the case of a woman who was diagnosed with RTHβ when she was 35 years old and was treated with 3,5,3-triiodiothyroacetic acid (TRIAC) because of the onset of clinical symptoms of hyperthyroidism. This therapy has been effective in controlling thyrotoxicosis for 5 years. After this time the patient developed an autoimmune hyperthyroidism, with TSH receptor autoantibodies appearance, which caused a loss of efficacy of the drug in controlling the disease. The development of different pathophysiological mechanisms of thyrotoxicosis, as in this case, could be the reason for both variability of disease manifestations and of loss of response to drug therapy.

The role of miR-139-5p in radioiodine-resistant thyroid cancer

PURPOSE

Radioiodine I-131 (RAI) is the therapy of choice for differentiated thyroid cancer (DTC). Between 5% and 15% of DTC patients become RAI refractory, due to the loss of expression/function of iodide metabolism components, especially the Na/I symporter (NIS). We searched for a miRNA profile associated with RAI-refractory DTC to identify novel biomarkers that could be potential targets for redifferentiation therapy.

METHODS

We analyzed the expression of 754 miRNAs in 26 DTC tissues: 12 responsive (R) and 14 non-responsive (NR) to RAI therapy. We identified 15 dysregulated miRNAs: 14 were upregulated, while only one (miR-139-5p) was downregulated in NR vs. R tumors. We investigated the role of miR-139-5p in iodine uptake metabolism. We overexpressed miR-139-5p in two primary and five immortalized thyroid cancer cell lines, and we analyzed the transcript and protein levels of NIS and its activation through iodine uptake assay and subcellular protein localization.

RESULTS

The finding of higher intracellular iodine levels and increased cell membrane protein localization in miR-139-5p overexpressing cells supports the role of this miRNA in the regulation of NIS function.

CONCLUSIONS

Our study provides evidence of miR-139-5p involvement in iodine uptake metabolism and suggests its possible role as a therapeutic target in restoring iodine uptake in RAI-refractory DTC.

Prospects of Testing Diurnal Profiles of Expressions of TSH-R and Circadian Clock Genes in Thyrocytes for Identification of Preoperative Biomarkers for Thyroid Carcinoma

Thyroid Nodules (TN) are frequent but mostly benign, and postoperative rate of benign TN attains the values from 70% to 90%. Therefore, there is an urgent need for identification of reliable preoperative diagnosis markers for patients with indeterminate thyroid cytology. In this study, an earlier unexplored design of research on preoperative biomarkers for thyroid malignancies was proposed. Evaluation of reported results of studies addressing the links of thyroid cancer to the circadian clockwork dysfunctions and abnormal activities of Thyroid-Stimulating Hormone (TSH) and its receptor (TSH-R) suggested diagnostic significance of such links. However, there is still a gap in studies of interrelationships between diurnal profiles of expression of circadian clock genes and TSH-R in indeterminate thyroid tissue exposed to different concentrations of TSH. These interrelationships might be investigated in future in vitro experiments on benign and malignant thyrocytes cultivated under normal and challenged TSH levels. Their design requires simultaneous measurement of diurnal profiles of expression of both circadian clock genes and TSH-R. Experimental results might help to bridge previous studies of preoperative biomarkers for thyroid carcinoma exploring diagnostic value of diurnal profiles of serum TSH levels, expression of TSH-R, and expression of circadian clock genes.

Seaweed and Iodine Intakes and SLC5A5 rs77277498 in Relation to Thyroid Cancer

BACKGRUOUND

This study aims to elucidate the associations among dietary seaweed (gim and miyeok/dashima) and iodine intakes, the rs77277498 polymorphism of the SLC5A5 gene codifying the sodium/iodine symporter, and thyroid cancer risk in a Korean population.

METHODS

We conducted a case-control study of 117 thyroid cancer cases and 173 controls who participated in the Cancer Screenee Cohort between 2002 and 2014 at the National Cancer Center, Korea. The amount of seaweed and iodine consumption (g/day) was estimated using the residual energy adjustment method. We calculated odds ratios (ORs) and their 95% confidence intervals (CIs) using a multivariable logistic regression model for the separate and combined effect of dietary iodine-based intake and SLC5A5 polymorphism (rs77277498, C>G) on thyroid cancer.

RESULTS

Dietary gim and iodine intakes were inversely associated with thyroid cancer, with ORs of 0.50 (95% CI, 0.30 to 0.83) and 0.57 (95% CI, 0.35 to 0.95), respectively, whereas the associations for dietary miyeok/dashima and total seaweed intakes were not significant. However, compared with individuals carrying the C/C genotype of the rs77277498 polymorphism with a low intake of all dietary factors, those carrying the G allele with a high intake had a lower risk of thyroid cancer, with ORs of 0.25 (95% CI, 0.10 to 0.56), 0.31 (95% CI, 0.12 to 0.77), 0.26 (95% CI, 0.10 to 0.62), and 0.30 (95% CI, 0.12 to 0.73) for the consumption of gim, miyeok/dashima, total seaweed, and iodine, respectively.

CONCLUSION

In summary, our results supported the evidence of the protective effects of dietary gim and iodine intake against thyroid cancer risk, and this association can be strengthened by SLC5A5 rs77277498 genotypes.

Identification of Exosomal microRNAs and Their Targets in Papillary Thyroid Cancer Cells

The release of molecules in exosomal cargoes is involved in tumor development and progression. We compared the profiles of exosomal microRNAs released by two thyroid cancer cell lines (TPC-1 and K1) with that of non-tumorigenic thyroid cells (Nthy-ori-3-1), and we explored the network of miRNA–target interaction. After extraction and characterization of exosomes, expression levels of microRNAs were investigated using custom TaqMan Advanced array cards, and compared with those expressed in the total cell extracts. The functional enrichment and network-based analysis of the miRNAs’ targets was also performed. Five microRNAs (miR-21-5p, miR-31-5p, miR-221-3p, miR-222-3p, and let-7i-3p) were significantly deregulated in the exosomes of tumor cells vs. non-tumorigenic cells, and three of them (miR-31-5p, miR-222-3p, and let-7i-3p) in the more aggressive K1 compared to TPC-1 cells. The network analysis of the five miRNAs identified some genes as targets of more than one miRNAs. These findings permitted the identification of exosomal microRNAs secreted by aggressive PTC cells, and indicated that their main targets are regulators of the tumor microenvironment. A deeper analysis of the functional role of the targets of exosomal miRNAs will provide further information on novel targets of molecular treatments for these neoplasms.

MicroRNAs in Papillary Thyroid Cancer: What Is New in Diagnosis and Treatment

Introduction

Papillary thyroid cancer (PTC) accounts for up to 80% of thyroid malignancies. New diagnostic and therapeutic options are suggested including innovative molecular methods. MicroRNAs (miRNAs) are nonprotein coding single-stranded RNAs that regulate many cell processes. The aim of the present study is to review the deregulated miRNAs associated with PTCs.

Methods

A bibliographic research was conducted, resulting in 272 articles referred to miRNAs and PTC. Regarding our exclusion criteria, 183 articles were finally included in our review.

Results

A remarkably large number of miRNAs have been found to be deregulated during PTC manifestation in the literature. The deregulated miRNAs are detected in tissue samples, serum/plasma, and FNA samples of patients with PTC. These miRNAs are related to several molecular pathways, involving genes and proteins responsible for important biological processes. MiRNA deregulation is associated with tumor aggressiveness, including larger tumor size, multifocality, extrathyroidal extension, lymphovascular invasion, lymph node and distant metastasis, and advanced tumor node metastasis stage.

Conclusion

MiRNAs are proposed as new diagnostic and therapeutic tools regarding PTC. They could be essential biomarkers for PTC diagnosis applied in serum and FNA samples, while their contribution to prognosis is of great importance.

The role of FOSL1 in stem-like cell reprogramming processes

Cancer stem-like cells (CSCs) have self-renewal abilities responsible for cancer progression, therapy resistance, and metastatic growth. The glioblastoma stem-like cells are the most studied among CSC populations. A recent study identified four transcription factors (SOX2, SALL2, OLIG2, and POU3F2) as the minimal core sufficient to reprogram differentiated glioblastoma (GBM) cells into stem-like cells. Transcriptomic data of GBM tissues and cell lines from two different datasets were then analyzed by the SWItch Miner (SWIM), a network-based software, and FOSL1 was identified as a putative regulator of the previously identified minimal core. Herein, we selected NTERA-2 and HEK293T cells to perform an in vitro study to investigate the role of FOSL1 in the reprogramming mechanisms. We transfected the two cell lines with a constitutive FOSL1 cDNA plasmid. We demonstrated that FOSL1 directly regulates the four transcription factors binding their promoter regions, is involved in the deregulation of several stemness markers, and reduces the cells' ability to generate aggregates increasing the extracellular matrix component FN1. Although further experiments are necessary, our data suggest that FOSL1 reprograms the stemness by regulating the core of the four transcription factors.

A review on the mechanism of iodide metabolic dysfunction in differentiated thyroid cancer

The incidence of differentiated thyroid cancer (DTC) has been increasing rapidly worldwide, and the risk factors remain unclear. With the growing number of patients with DTC, the related issues have been gradually highlighted. ¹³¹Iodide (¹³¹I) is an important treatment for DTC and has the potential to reduce the risk of recurrence. ¹³¹I is also an effective treatment for distant metastases of thyroid carcinoma. However, iodide metabolism dysfunction in metastatic foci causes patients to lose the opportunity of ¹³¹I treatment. This article reviews the related mechanisms of iodide metabolism dysfunction in DTC cells and summarizes the clinical transformation progression.

Follow-up of differentiated thyroid cancer - what should (and what should not) be done

The treatment paradigm for thyroid cancer has shifted from a one-size-fits-all approach to more personalized protocols that range from active surveillance to total thyroidectomy followed by radioiodine remnant ablation. Accurate surveillance tools are available, but follow-up protocols vary widely between centres and clinicians, owing to the lack of clear, straightforward recommendations on the instruments and assessment schedule that health-care professionals should adopt. For most patients (that is, those who have had an excellent response to the initial treatment and have a low or intermediate risk of tumour recurrence), an infrequent assessment schedule is sufficient (such as a yearly determination of serum levels of TSH and thyroglobulin). Select patients will benefit from second-line imaging and more frequent assessments. This Review discusses the strengths and weaknesses of the surveillance tools and follow-up strategies that clinicians use as a function of the initial treatment and each patient's risk of recurrence.

MiRNA-221/222 in thyroid cancer: A meta-analysis

OBJECTIVES

A meta-analysis was performed to observe whether a difference in miRNA-221/222 expression exists in thyroid cancer with normal thyroid or BTLs (benign thyroid lesions) and, under this premise, assess its diagnostic efficacy for thyroid cancer.

METHODS

Systematic electronic literature searches were conducted to include PubMed, the Cochrane Central Register of Controlled Trials, and Web of Science. The combined fold change (FC) was calculated, and pooled estimates of sensitivity, specificity, diagnostic odds ratio (DOR) and summary receiver operating characteristic (SROC) curves were calculated.

RESULTS

Twenty-seven articles were included in this meta-analysis. The combined FC of miRNA-221/222 were 13.85 and 13.75 in thyroid cancer with normal control. For miRNA-221/222, the pooled sensitivity was 0.79 (95% CI = 0.73-0.85), specificity was 0.84 (95% CI = 0.76-0.90) and AUC (area under the curve) value was 0.88 (0.85-0.91). For miRNA-221, the pooled sensitivity was 0.82 (95% CI = 0.76-0.86) and specificity was 0.84 (95%CI = 0.74-0.91). For miRNA-222, the pooled sensitivity was 0.78 (95%CI = 0.68-0.85) and specificity was 0.83 (95% CI = 0.70-0.92).

CONCLUSION

Differences in expression levels of miRNA-221/222 can provide clues for exploring the etiology of thyroid cancer. In addition, miRNA-221/222 were promising molecular biomarkers that may significantly improve the diagnostic accuracy of thyroid cancer.

Overexpressing modified human TRβ1 suppresses the proliferation of breast cancer MDA-MB-468 cells

A number of studies have indicated that thyroid hormone receptor β1 (TRβ1) functions as a tumor suppressor. TRs mediate transcriptional responses through a highly conserved DNA-binding domain (DBD). A novel rat TRβ isoform (rTRβΔ) was previously identified, in which a novel exon, N (108 bp), is located between exons 3 and 4 within the DBD; this exon represents the only difference between rTRβΔ and rTRβ1. In vitro, rTRβΔ exhibits a stronger tumor-suppressive capacity than rTRβ1, and further analysis revealed a high level of conservation between the rat and human DBD sequences. In the present study, an artificially modified human TRβ1 (m-hTRβ1) was constructed via the introduction of the 108-bp sequence into the corresponding position of the wild-type human TRβ1 (wt-hTRβ1) DBD. An electrophoretic mobility shift assay and transfection experiments confirmed that m-hTRβ1 is functional. Overexpression of m-hTRβ1 inhibits the proliferation of MDA-MB-468 cells in the presence of triiodothyronine by promoting apoptosis, which may be associated with the upregulation of Caspase-3 and Bak gene expression and the activation of the Caspase-3 protein. In addition, the pro-apoptotic effect of m-hTRβ1 was stronger, compared with wt-hTRβ1. These results indicated that m-hTRβ1 may act as a tumor suppressor in MDA-MB-468 cells. These data provided a novel insight into gene therapy for breast cancer.

Overexpression of modified human TRβ1 suppresses the growth of hepatocarcinoma SK-hep1 cells in vitro and in xenograft models

Association studies suggest that TRβ1 functions as a tumor suppressor. Thyroid hormone receptors (TRs) mediate transcriptional responses through a highly conserved DNA-binding domain (DBD). We previously constructed an artificially modified human TRβ1 (m-TRβ1) via the introduction of a 108-bp exon sequence into the corresponding position of the wild-type human TRβ1 (TRβ1) DBD. Studies confirmed that m-TRβ1 was functional and could inhibit the proliferation of breast cancer MDA-MB-468 cells in vitro. To understand the role of m-TRβ1 in liver tumor development, we adopted a gain-of-function approach by stably expressing TRβ (m-TRβ1 and TRβ1) genes in a human hepatocarcinoma cell line, SK-hep1 (without endogenous TRβ), and then evaluated the effects of the expressed TRβ on cancer cell proliferation, migration, and tumor growth in cell-based studies and xenograft models. In the presence of 3,5,3-l-triiodothyronine (T3), the expression of TRβ in SK-hep1 cells inhibited cancer cell proliferation and impeded tumor cell migration through the up-regulation of 4-1BB, Caspase-3, and Bak gene expression; down-regulation of Bcl-2 gene expression; and activation of the Caspase-3 protein. TRβ expression in SK-hep1 led to less tumor growth in xenograft models. Additionally, the anti-tumor effect of m-TRβ1 was stronger than that of TRβ1. These data indicate that m-TRβ1 can act as a tumor suppressor in hepatocarcinoma and its role was significantly better than that of TRβ1.

The role of microRNAs in different types of thyroid carcinoma: a comprehensive analysis to find new miRNA supplementary therapies

The most common endocrine malignancy is thyroid cancer, and researchers have made a great deal of progress in deciphering its molecular mechanisms in the recent years. Many of molecular changes observed in thyroid cancer can be used as biomarkers for diagnosis, prognosis, and therapeutic targets for treatment. MicroRNAs (miRNAs) are important parts in biological and metabolic pathways such as regulation of developmental stages, signal transduction, cell maintenance, and differentiation. Therefore, their dysregulation can expose individuals to malignancies. It has been proved that miRNA expression is dysregulated in different types of tumors, like thyroid cancers, and can be the cause of tumor initiation and progression. In this paper, we have reviewed the available data on miRNA dysregulation in different thyroid tumors including papillary, follicular, anaplastic, and medullary thyroid carcinomas aiming to introduce the last updates in miRNAs-thyroid cancer relation.

Effects of nutraceuticals on anaplastic thyroid cancer cells

PURPOSE

The anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer with a high mortality rate. Since nutraceuticals may exert beneficial effects on tumor biology, here, effects of four of these compounds [resveratrol, genistein, curcumin and epigallocatechin-3-gallate (EGCG)] on ATC cell lines were investigated.

METHODS

Two ATC-derived cell lines were used: SW1736 and 8505C. Cell viability and in vitro aggressiveness was tested by MTT and soft agar assays. Apoptosis was investigated by Western Blot, using an anti-cleaved-PARP antibody. mRNA and miRNA levels were quantified by real-time PCR.

RESULTS

All tested nutraceuticals caused in both cell lines decrease of cell viability and increase of apoptosis. In contrast, only curcumin reduced in vitro aggressiveness in both SW1736 and 8505C cell lines, while genistein and EGCG determined a reduction of colony formation only in 8505C cells. Effects on genes related to the thyroid-differentiated phenotype were also tested: resveratrol and genistein administration determined the increment of almost all tested mRNAs in both cell lines. Instead curcumin and EGCG treatments had opposite effects in the two cell lines, causing the increment of almost all the mRNAs in 8505C cells and their reduction in SW1736. Finally, effects of nutraceuticals on levels of several miRNAs, known as important in thyroid cancer progression (hsa-miR-221, hsa-miR-222, hsa-miR-21, hsa-miR-146b, hsa-miR-204), were tested. Curcumin induced a strong and significant reduction of all miR analyzed, except for has-miR-204, in both cell lines.

CONCLUSIONS

Altogether, our results clearly indicate the anti-cancer proprieties of curcumin, suggesting the promising use of this nutraceutical in ATC treatment. Resveratrol, genistein and EGCG have heterogeneous effects on molecular features of ATC cells.

The Role of the NIS (SLC5A5) Gene in Papillary Thyroid Cancer: A Systematic Review

Papillary thyroid cancer (PTC) is the most common thyroid malignancy. Genetic and epigenetic alterations play a decisive role in the onset of several human neoplasms. Mutations and polymorphisms are two frequent genetic alterations. Located on chromosome 19 (19p13.11), the NIS SLC5A5 (solute carrier family 5 member 5) gene encodes a highly specialized and efficient 80-90 kDa transmembrane glycoprotein that mediates active transport of iodide from the bloodstream into the follicular cells. Given the highly significant role of NIS in the physiology and the cancer pathogenesis process, this paper's objective is to provide a comprehensive assessment of the associations between NIS gene and protein with papillary thyroid cancer.

BRAF-Oncogene-Induced Senescence and the Role of Thyroid-Stimulating Hormone Signaling in the Progression of Papillary Thyroid Carcinoma

Oncogene-induced senescence (OIS) explains the phenomenon of cellular senescence triggered by the action of oncogenes. It is a mechanism adopted by a cell to inhibit progression of benign tumors into malignancy, occurs in premalignant lesions, and is almost never present in malignant lesions. BRAF mutations occur in about 40-45% of all papillary thyroid carcinomas (PTCs) and of which 99.7% is the BRAFV600E mutation. A unique phenotype of the BRAFV600E mutation is the upregulation of the thyroid-stimulating hormone receptor (TSHR) on thyrocyte membranes. Despite the overexpression of the receptor, BRAFV600E cells undergo cell cycle arrest leading to OIS via a negative feedback signaling mechanism. A simultaneous increase in serum thyroid-stimulating hormone (TSH) in response to hypothyroidism (common in autoimmune diseases such as Hashimoto's thyroiditis) would cause senescent tumor cells to overcome OIS and proceed towards malignancy, hence showing the importance of TSH/TSHR signaling in the development of PTCs. Increase in TSH/TSHR signaling triggers an increase in levels of downstream enzymes such as manganese superoxide dismutase (MnSOD) and dual-specific phosphatase 6 (DUSP6) which eventually results in the production of oncogenic proteins such as c-Myc. Therefore, the detection of these genetic alterations as effective biomarkers for premalignant lesions of PTC is important in clinical settings and techniques such as polymerase chain reaction-mediated restriction fragment length polymorphism (PCR-RFLP) and real-time PCR can be used to detect the BRAFV600E point mutation and overexpression of TSHR, MnSOD, and DUSP6, respectively.

Association of PDCD1 gene markers with susceptibility to thyroid cancer

PURPOSE

PD-1 receptor is a co-signaling molecule with an important role in regulation of T-lymphocyte activity. Correlation between PD-1 gene (PDCD1) polymorphisms and some immune-related diseases has been reported before. In current study, we aimed to investigate the association of PD-1 polymorphisms at positions +7146 G/A (PD-1.3) and +7785 C/T (PD-1.5), as well as the emerged haplotypes with susceptibility to thyroid carcinoma.

METHODS

One hundred five patients with confirmed thyroid cancer and 160 healthy individuals as control group were enrolled. Genotypes were identified using PCR-RFLP and nested PCR-RFLP methods. Results were analyzed by Arlequin and SPSS software packages.

RESULTS

Analysis revealed a significant increase in the frequency of PD-1.5 mutant T allele and heterozygous CT genotype in patients with thyroid cancer in comparison with controls [79 (37.7%) vs. 71 (22.2%), and 51 (48.6%) vs. 51 (31.9%), p = 0.0001 and p = 0.009, receptively]. CC genotype at this position observed to be significantly higher among controls than the patients [99 (61.9%) vs. 40 (38.1%), p = 0.0002]. There were no significant differences in the frequencies of genotypes and alleles at locus PD-1.3 between patients and control group. Despite this, GT haplotype emerged from both positions (PD-1.3 G and PD-1.5 T) has also been observed with significant increased frequency between patients and controls [70 (36.8%) vs. 71 (22.2%), p = 0.0005].

CONCLUSION

As the first study to investigate two mentioned polymorphisms in thyroid cancer, current study confirmed the association of PD-1.5 C/T polymorphism and a haplotype resulted from both loci, PD-1.3 and PD-1.5, with susceptibility of Iranians to thyroid cancer.

MicroRNA-based molecular classification of papillary thyroid carcinoma

MicroRNA (miRNA) expression is dysregulated in many human malignancies, and a growing number of studies are focused on their potential use as tumor biomarkers. To identify a miRNA signature for papillary thyroid carcinomas (PTC), we investigated miRNA expression profiles in two independent cohorts of PTCs, which included major histological subtypes [classical-type (PTC‑CT), follicular-variant (PTC‑FV), and tall-cell variant (PTC‑TCV)] and cases with low or intermediate risk of recurrence. Using TaqMan® Array Human MicroRNA A+B Cards v3.0, we first performed microRNA profiling of normal and neoplastic thyroid tissues from 29 PTC patients. Promising candidates were then investigated in a second, independent cohort of 76 PTCs using Custom TaqMan® Array MicroRNA Cards. We identified a molecular signature of 11 miRNAs that were significantly upregulated (miR‑146b-5p, miR‑146b-3p, miR‑221-3p, miR‑222‑5p, miR‑222‑3p) or downregulated (miR‑1179, miR‑486‑5p, miR‑204-5p, miR‑7-2-3p, miR‑144-5p, miR‑140-3p) in PTC tissues vs. normal thyroid tissue. Upregulation of miR‑146b-5p and miR‑222‑3p was also significantly associated with an increased risk of recurrence. Higher than normal expression of miR‑146b-5p and miR‑146b-3p characterized PTC‑CT and PTC‑TCV but not PTC‑FV, whereas miR‑21-5p was significantly upregulated only in PTC‑TCV. When PTC‑FV were subclassified as encapsulated (PTC‑EFV) or infiltrative (PTC‑IFV), miR‑204-5p was downregulated in all histological subtypes except PTC‑EFV, which displayed expression levels similar to those of normal thyroid tissues. These findings provide new insights into the molecular classification of PTC, showing that different miRNA expression profiles are associated with different histological types of PTC and different risks of recurrence.

Key genes and pathways predicted in papillary thyroid carcinoma based on bioinformatics analysis

PURPOSE

The aim of this study was to predict the key genes and pathways associated with papillary thyroid carcinoma (PTC).

METHODS

Based on the microarray data of GSE3467 from Gene Expression Omnibus database, we identified the differentially expressed genes (DEGs) between 9 PTC samples and 9 normal controls. With the identified DEGs, functional enrichment analyses were performed. Additionally, a protein-protein interaction network was constructed to screened out some key gene nodes. These key nodes were then performed clustering analysis and pathway enrichment analysis. Furthermore, human PTC-associated network was constructed based on these key genes to investigate the potential relationships between genes and PTC.

RESULTS

A total of 651 up-regulated and 692 down-regulated DEGs were identified in PTC samples compared with controls. The up-regulated DEGs, such as complement component 3 (C3), were mainly enriched in hsa04610:Complement and coagulation cascades. The down-regulated DEGs, including paired box 8 (PAX8), peroxisome proliferator-activated receptor gamma (PPARG), and cadherin 1, type 1 were found enriched in hsa05216:Thyroid cancer. Total 33 DEGs were considered as key genes, such as PAX8, PPARG and Jun proto-oncogene (JUN). Disease-associated network analysis found that 15 key genes such as JUN, PPARG and matrix metallopeptidase 9 (MMP9) were involved in this network.

CONCLUSIONS

DEGs of C3, PPARG, PAX8, JUN and MMP9 were differentially expressed in PTC samples and may be used as potential biomarkers in the diagnosis and treatment of PTC. Additionally, pathways of complement and coagulation cascades and thyroid cancer may also play important roles in the development of PTC.

Fibronectin-1 expression is increased in aggressive thyroid cancer and favors the migration and invasion of cancer cells

In this study we analyzed the expression levels of markers of epithelial-to-mesenchymal transition (EMT) in several papillary thyroid carcinomas (PTCs) and the relation with tumor genotypes and clinicopathological characteristics. The role of fibronectin-1 (FN1) was investigated by analyzing the effects of FN1 silencing in two human thyroid cancer cell lines. Most of EMT markers were significantly over-expressed in a group of 36 PTCs. In particular, FN1 mRNA levels were higher in tumor vs non-tumor tissue (117.3, p < 0.001) and also in aggressive and BRAF(V600E) samples. Similar results were observed (and confirmed at the protein level) when FN1 expression was analyzed in a validation group of 50 PTCs and six lymph node (LN) metastases. Silencing of FN1 in TPC-1 and BCPAP thyroid cancer cells significantly reduced proliferation, adhesion, migration, and invasion in both cell lines. Collectively, our data indicate that FN1 overexpression is an important determinant of thyroid cancer aggressiveness.

T3/TRs axis in hepatocellular carcinoma: new concepts for an old pair

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, and its burden is expected to further increase in the next years. Chronic inflammation, induced by multiple viruses or metabolic alterations, and epigenetic and genetic modifications, cooperate in cancer development via a combination of common and distinct aetiology-specific pathways. In spite of the advances of classical therapies, the prognosis of this neoplasm has not considerably improved over the past few years. The advent of targeted therapies and the approval of the systemic treatment of advanced HCC with the kinase inhibitor sorafenib have provided some hope for the future. However, the benefits obtained from this treatment are still disappointing, as it extends the median life expectancy of patients by only few months. It is thus mandatory to find alternative effective treatments. Although the role played by thyroid hormones (THs) and their nuclear receptors (TRs) in human cancer is still unclear, mounting evidence indicates that they behave as oncosuppressors in HCC. However, the molecular mechanisms by which they exert this effect and the consequence of their activation following ligand binding on HCC progression remain elusive. In this review, we re-evaluate the existing evidence of the role of TH/TRs in HCC development; we will also discuss how TR alterations could affect fundamental biological processes, such as hepatocyte proliferation and differentiation, and consequently HCC progression. Finally, we will discuss if and how TRs can be foreseen as therapeutic targets in HCC and whether selective TR modulation by TH analogues may hold promise for HCC treatment.

Molecular profiles of cancer stem-like cell populations in aggressive thyroid cancers

A substantial proportion of patients with advanced thyroid carcinoma fail to respond to or at some point become refractory to conventional therapies. This resistance and the phenomena of thyroid cancer progression and metastasis themselves are thought to be related to tumor-cell sub-populations with stem-like properties. We isolated thyrospheres from four advanced thyroid carcinomas that were resistant to radioiodine therapy and analyzed their molecular profiles. ALDH activity and proteomic profile of main stem cell markers were used to assess stem cell properties. The TaqMan Low Density Array approach was used to evaluate the expression of several genes involved in the EMT process. The phosphorylation status of tyrosine kinase receptors (RTKs) was analyzed to identify potential markers for targeted therapies. We then investigated the effects of the EMT-inhibitor crizotinib on both cell proliferation and phosphorylation status of RTK targets. The cancer stem-like properties of a subset of cells from primary cultures of each tumor were demonstrated. A wide variability among thyrospheres arising from the four thyroid cancers in terms of ALDH activity, stem cell marker expression, and phosphoproteome profiling was present. Dysregulated expression of genes involved in the EMT was observed in all four thyrosphere lines. Treatment with crizotinib was ineffective in cancer stem-like cells, suggesting the presence of a mechanism of resistance in thyrospheres. Collectively, our data indicate that thyroid cancer stem-like populations vary markedly from tumor to tumor and require detailed molecular and biological characterization if they are to be used as the basis of "personalized" treatment of aggressive disease.

Expression of PAX8 Target Genes in Papillary Thyroid Carcinoma

PAX8 is a thyroid-specific transcription factor whose expression is dysregulated in thyroid cancer. A recent study using a conditional knock-out mouse model identified 58 putative PAX8 target genes. In the present study, we evaluated the expression of 11 of these genes in normal and tumoral thyroid tissues from patients with papillary thyroid cancer (PTC). ATP1B1, GPC3, KCNIP3, and PRLR transcript levels in tumor tissues were significantly lower in PTCs than in NT, whereas LCN2, LGALS1 and SCD1 expression was upregulated in PTC compared with NT. Principal component analysis of the expression of the most markedly dysregulated PAX8 target genes was able to discriminate between PTC and NT. Immunohistochemistry was used to assess levels of proteins encoded by the two most dyregulated PAX8 target genes, LCN2 and GPC3. Interestingly, GPC3 was detectable in all of the NT samples but none of the PTC samples. Collectively, these findings point to significant PTC-associated dysregulation of several PAX8 target genes, supporting the notion that PAX8-regulated molecular cascades play important roles during thyroid tumorigenesis.