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Radioiodine-refractory thyroid cancers represent the main cause of thyroid cancer-related death. At present, targeted therapies with multikinase inhibitors represent a unique therapeutic tool, though they have limited benefit on patient survival and severe drug-associated adverse events. This review summarizes current treatment strategies for radioiodine-refractory thyroid cancer and focuses on novel approaches to redifferentiate thyroid cancer cells to restore responsiveness to radioiodine administration.We summarize and discuss recent clinical trial findings and early data from real-life experiences with multikinase-inhibiting drugs. Possible alternative strategies to traditional redifferentiation are also discussed.The current review focuses primarily on the major advancements in the knowledge of the pathophysiology of iodine transport and metabolism and the genetic and epigenetic alterations occurring in thyroid neoplasia as described using preclinical models. Results of clinical studies employing new compounds to induce thyroid cancer cell redifferentiation by acting against specific molecular targets are also discussed. Finally, we describe the current scenario emerging from such findings as well as future perspectives.

Introduction: Despite the low frequency of Covid-19-associated bacterial infections, empirical antibacterial treatment is as high as 70 to 90%. The primary goal of this study was to determine the impact of the implementation of an antimicrobial stewardship program to target Covid-19 patients (ASP-COVID). Materials and methods: Retrospective, descriptive, and analytic pre and post intervention study. Prevalence and adequacy of antibacterial treatment in hospitalized patients prior and after ASP-COVID implementation were assessed. Monthly antibiotic consumption in DDD/100 patients-day and costs related with inadequate usage were estimated. Results: One hundred and fifty three patients, 75 prior and 78 after ASP-COVID implementation, were included. No significant difference in population characteristics between both periods was observed. Moderate and severe clinical presentations were more frequent after the intervention (p=0,03). ASP implementation showed a significant reduction of antimicrobial treatment (64% vs 41%, p=0,004), with an increment of adequate usage (37,5% vs 46,8%, p=NS). Unnecessary usage was higher prior to ASP (80% vs 50%, p =0,03) and length of treatment post intervention (13,3% vs 43,7%%, p=0,02). Program implementation decreased beta lactam antibiotics + IBL and azithromycin consumption. After adjusting for severity, no significant difference was found in mortality, incidence of ICU admission nor combined antibacterial therapy with macrolides between both periods. Conclusions: ASP-COVID implementation was an effective strategy in reducing antimicrobial usage and in optimizing antibacterial treatment indications, highlighting the importance of its rapid and timely application.

Insulin resistance (IR), defined as an attenuated biological response to circulating insulin, is a fundamental defect in obesity and type 2 diabetes (T2D), and is also linked to a wide spectrum of pathological conditions, such as non-alcoholic fatty liver disease (NAFLD), cognitive impairment, endothelial dysfunction, chronic kidney disease (CKD), polycystic ovary syndrome (PCOS), and some endocrine tumors, including breast cancer. In obesity, the unbalanced production of pro- and anti-inflammatory adipocytokines can lead to the development of IR and its related metabolic complications, which are potentially reversible through weight-loss programs. The Mediterranean diet (MedDiet), characterized by high consumption of extra-virgin olive oil (EVOO), nuts, red wine, vegetables and other polyphenol-rich elements, has proved to be associated with greater improvement of IR in obese individuals, when compared to other nutritional interventions. Also, recent studies in either experimental animal models or in humans, have shown encouraging results for insulin-sensitizing nutritional supplements derived from MedDiet food sources in the modulation of pathognomonic traits of certain IR-related conditions, including polyunsaturated fatty acids from olive oil and seeds, anthocyanins from purple vegetables and fruits, resveratrol from grapes, and the EVOO-derived, oleacein. Although the pharmacological properties and clinical uses of these functional nutrients are still under investigation, the molecular mechanism(s) underlying the metabolic benefits appear to be compound-specific and, in some cases, point to a role in gene expression through an involvement of the nuclear high-mobility group A1 (HMGA1) protein.

Exposure to environmental endocrine disruptors has been associated with an increased frequency of thyroid pathology. In this study, we evaluated the effects of various concentrations of methylmercury (MeHg) on immortalized, non-tumorigenic thyroid cells (Nthy-ori-3-1). Exposure to MeHg at 2.5 and 5 &micro, M for 24 h caused a reduction in cell viability with a decrease of the cell population in sub-G0 phase, as detected by MTT and flow cytometry. Conversely, MeHg at the lower concentration of 0.1 &micro, M increased the cell viability with a rise of G2/M phase. An immunoblot analysis showed higher expression levels of phospho-ERK and not of phospho-Akt. Further enhancement of the cell growth rate was observed after a prolonged exposure of the cells up to 18 days to MeHg 0.1 &micro, M. The present findings demonstrate the toxicity of high concentrations of MeHg on thyroid cells, while showing that treatment with lower doses of Hg, as may occur after prolonged exposure to this environmental contaminant, exerts a promoting effect on thyroid cell proliferation, by acting on the ERK-mediated pro-oncogenic signal transduction pathway.

Aim of this study was to evaluate the association between body mass index (BMI) and aggressive features of differentiated thyroid cancer (DTC) in a prospective cohort. Patients with DTC were prospectively enrolled at a tertiary referral center and grouped according to their BMI. Aggressive clinic-pathological features were analyzed following the American Thyroid Association Initial Risk Stratification System score. The cohort was composed of 432 patients: 5 (1.2%) were underweight, 187 (43.3%) normal weight, 154 (35.6%) overweight, 68 (15.7%) grade 1 obese, 11 (2.5%) grade 2 obese and 7 (1.6%) grade 3 obese. No single feature of advanced thyroid cancer was more frequent in obese patients than in others. No significant correlation was found between BMI, primary tumor size (Spearman’s ρ − 0.02; p = 0.71) and ATA Initial Risk Stratification System score (ρ 0.03; p = 0.49), after adjustment for age. According to the multivariate logistic regression analysis, male gender and pre-surgical diagnosis of cancer were significant predictors of cancer with high or intermediate–high recurrence risk according to the ATA system (OR 2.06 and 2.51, respectively), while older age at diagnosis was a protective factor (OR 0.98), and BMI was not a predictor. BMI was a predictor of microscopic extrathyroidal extension only (OR 1.06). Obesity was not associated with aggressive features in this prospective, European cohort of patients with DTC.

C-peptide has been shown to exert several, previously unknown, biological effects. A recent cross-sectional study demonstrated an association between low C-peptide serum levels and low lumbar bone density of postmenopausal women not affected by diabetes. To date, very little research attention has been directed toward the association between C-peptide and osteoporotic fractures. To contribute toward filling this gap, we investigated the association between C-peptide and fractures in postmenopausal women. A cohort of 133 non-diabetic postmenopausal women with and without a history of fractures was evaluated in this cross-sectional investigation. Standardized interviews were performed to gather information on the patients’ fracture history. All of the participants underwent a bone mineral density assessment by DXA, radiographs, and a serum C-peptide measurement. Thirty-four women presented fractures. Bivariate analysis revealed an inverse correlation between C-peptide and fractures (r = −0.27, p = 0.002). A significant difference in mean C-peptide levels was also found between women with vs. without fractures (p = 0.01, adjusted for age, BMI and glucose). Logistic regression analysis showed that C-peptide levels, femoral and vertebral BMD were all negatively associated with fracture status (B = −1.097, ES = 0.401, p = 0.006, 95% CI 0.15–0.73; B = −15.6, SE = 4.17, p

Optimal management of patients with thyroid cancer requires the use of sensitive and specific biomarkers. For early diagnosis and effective follow-up, the currently available cytological and serum biomarkers, thyroglobulin and calcitonin, present severe limitations. Research on microRNA expression in thyroid tumors is providing new insights for the development of novel biomarkers that can be used to diagnose thyroid cancer and optimize its management. In this review, we will examine some of the methods commonly used to detect and quantify microRNA in biospecimens from patients with thyroid tumor, as well as the potential applications of these techniques for developing microRNA-based biomarkers for the diagnosis and prognostic evaluation of thyroid cancers.

Growing evidence shows that dietary composition has a marked impact on the risk of developing obesity, type 2 diabetes (T2D), cardiovascular disease (CVD), certain types of endocrine cancer and many other intertwined metabolic and reproductive disorders, all featured by insulin resistance (IR) [...]

Many reports indicate that the protective action of nutraceuticals in the Mediterranean diet, against metabolic and cardiovascular diseases, can be attributed to the action of polyphenolic components of extra-virgin olive oil (EVOO). Here, we evaluated the protective effects of oleacein, one of the most abundant secoiridoids in EVOO, on the damages/metabolic alterations caused by high-fat diet (HFD) in male C57BL/6JolaHsd mice. After 5 weeks of treatment with 20 mg/kg of oleacein, body weight, glycemia, insulinemia, serum lipids, and histologic examination of liver tissue indicated a protective action of oleacein against abdominal fat accumulation, weight gain, and liver steatosis, with improvement of insulin-dependent glucose and lipid metabolism. Both serum parameters and hepatic histologic examination were altered in mice fed with HFD. By contrast, in the animals that received oleacein, plasma glucose, cholesterol and triglyceride serum levels, and liver histology were similar to controls fed with normocaloric diet. In addition, protein levels of FAS, SREBP-1, and phospho-ERK in liver were positively modulated by oleacein, indicating an improvement in liver insulin sensitivity. In a group of obese mice, treatment with oleacein determined a light, but still significant reduction of the increase in body weight, mainly due to lesser liver steatosis enlargement, associated with reduced levels of SREBP-1 and phospho-ERK and lower levels of total serum cholesterol; in these animals, altered plasma glucose and triglyceride serum levels were not reverted by oleacein. These results indicate that HFD-related hepatic insulin resistance may be partially prevented by oral administration of oleacein, suggesting a protective role of this nutraceutical against diet-dependent metabolic alterations. Additional studies are necessary to check whether oleacein can be used as an adjuvant to improve insulin sensitivity in humans.

Effects of flavonoids extracted from Citrus reticulata (mandarin) juice on proliferation and migration of 3 human anaplastic thyroid carcinoma (ATC) cell lines were evaluated. Flavonoid components of Mandarin juice extract (MJe) were analyzed by uHPLC. Proliferation of CAL-62, C-643, and 8505C cells, measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, was significantly reduced by MJe in a concentration- and time-dependent way, with maximal effect elicited at 0.5 mg/ml concentration after 48 h. Cytofluorimetric analysis showed a block in the G2/M phase of the cell cycle, accompanied by low cell mortality owed to autophagic death. The extract caused also a reduction of cell migration, associated with decreased activity of the metalloproteinase MMP-2. These findings demonstrate that the flavonoid fraction of mandarin juice exerts in vitro antiproliferative effects on ATC cells, associated with a reduction of migration, suggesting for such a functional food a potential use as adjuvant in the treatment of thyroid cancer.

Recent studies have revealed in normal thyroid tissue the presence of the transcript of several phosphodiesterases (PDEs), enzymes responsible for the hydrolysis of cyclic nucleotides. In this work, we analyzed the expression of PDE5 in a series of human papillary thyroid carcinomas (PTCs) presenting or not BRAF V600E mutation and classified according to ATA risk criteria. Furthermore, we tested the effects of two PDE5 inhibitors (sildenafil, tadalafil) against human thyroid cancer cells. PDE5 gene and protein expression were analyzed in two different cohorts of PTCs by real-time PCR using a TaqMan micro-fluid card system and Western blot. MTT and migration assay were used to evaluate the effects of PDE5 inhibitors on proliferation and migration of TPC-1, BCPAP, and 8505C cells. In a first series of 36 PTCs, we found higher expression levels of PDE5A in tumors versus non-tumor (normal) tissues. PTCs with BRAF mutation showed higher levels of mRNA compared with those without mutation. No significant differences were detected between subgroups with low and intermediate ATA risk. Upregulation of PDE5 was also detected in tumor tissue proteins. Similar results were obtained analyzing the second cohort of 50 PTCs. Moreover, all tumor tissues with high PDE5 levels showed reduction of Thyroglobulin, TSH receptor, Thyroperoxidase, and NIS transcripts. In thyroid cancer cells in vitro, sildenafil and tadalafil determined a reduction of proliferation and cellular migration. Our findings demonstrate for the first time an overexpression of PDE5 in PTCs, and the ability of PDE5 inhibitors to block the proliferation of thyroid cancer cells in culture, therefore, suggesting that specific inhibition of PDE5 may be proposed for the treatment of these tumors.

The high consumption of olive tree products in the Mediterranean diet has been associated with a lower incidence of metabolic disorders and cardiovascular diseases. In particular, the protective effects of olive oil have been attributed to the presence of polyphenols such as oleuropein (Ole) and its derivatives. We have synthesized a peracetylated derivative of Ole (Ac-Ole) which has shownin vitroantioxidant and growth-inhibitory activity higher than the natural molecule. In this study, male C57BL/6JOlaHsd mice were fed with a standard (std), cafeteria (caf) diet, and caf diet supplemented with Ole (0.037 mmol/kg/day) and Ac-Ole (0.025 mmol/kg/day) for 15 weeks. We observed a significant reduction in the caf diet-induced body weight gain and increase of abdominal adipose tissue. Also, Ole and Ac-Ole prevented the development of hepatic steatosis. Finally, Ole and Ac-Ole determined a lower increase of HDL and LDL-cholesterol levels and corrected caf diet-induced elevation of plasma glucose concentrations by improving insulin sensitivity. The observed beneficial properties of Ole and Ac-Ole make these compounds and in particular Ac-Ole promising candidates for a potential pharmaceutic use in metabolic disorders.

Application of distinct technologies of cancer genome analysis has provided important information for the molecular characterization of several human neoplasia, including follicular cell-derived thyroid carcinoma. Among them, comparative genomic hybridization (CGH)-based procedures have been extensively applied to evaluate genomic imbalances present in these tumours, obtaining data leading to an increase in the understanding of their complexity and diversity. In this review, after a brief overview of the most commonly used CGH-based technichs, we will describe the major results deriving from the most influential studies in the literature which used this approach to investigate the genomic aberrations of thyroid cancer cells. In most studies a small number of patients have been analyzed. Deletions and duplications at different chromosomal regions were detected in all investigated cohorts. A higher number of genomic imbalances has been detected in anaplastic or poorly differentiated thyroid carcinomas compared to well differentiated ones. Limitations in the interpretation of the results, as well the potential impact in the clinical practice are discussed. Though a quite heterogeneous picture arises from results so far available, CGH array, combined with other methodologies as well as an accurate clinical management, may offer novel opportunities for a better stratification of thyroid cancer patients.

SummaryIntroduction A relationship between vestibular disorders and thyroid autoimmunity independently from thyroid function has been postulated. Aim To shed more light on the actual relationship between vestibular lesions and Hashimoto's thyroiditis (HT) regardless of thyroid function. Methods Forty-seven patients with HT (89·4% F; aged 48·3 ± 12·7 years), 21 with multinodular goitre (MNG; 57·1% F; 54·1 ± 9·8 years) and 30 healthy volunteers (56·7% F; 50·7 ± 13·9 years) were enrolled. Inclusion criteria were the presence of normal thyroid function tests and no clinical history of vestibular dysfunction. Each subject was submitted to complete vestibular evaluation [Caloric Test, Vestibular evoked myogenic potentials (VEMPs), Head Shaking Test (HST)]. Results 52·2% of HT patients showed an alteration of VEMPs and 44·7% of caloric test (P

Oleacein is one of the most abundant polyphenolic compounds of olive oil, which has been shown to play a protective role against several metabolic abnormalities, including dyslipidemia, insulin resistance, and glucose intolerance. Herein, we investigated the effects of oleacein on certain markers of adipogenesis and insulin-resistance in vitro, in 3T3-L1 adipocytes, and in vivo in high-fat diet (HFD)-fed mice. During the differentiation process of 3T3-L1 preadipocytes into adipocytes, oleacein strongly inhibited lipid accumulation, and decreased protein levels of peroxisome proliferator-activated receptor gamma (PPAR&gamma, ) and fatty acid synthase (FAS), while increasing Adiponectin levels. In vivo, treatment with oleacein of C57BL/6JOlaHsd mice fed with HFD for 5 and 13 weeks prevented the increase in adipocyte size and reduced the inflammatory infiltration of macrophages and lymphocytes in adipose tissue. These effects were accompanied by changes in the expression of adipose tissue-specific regulatory elements such as PPAR&gamma, FAS, sterol regulatory element-binding transcription factor-1 (SREBP-1), and Adiponectin, while the expression of insulin-sensitive muscle/fat glucose transporter Glut-4 was restored in HFD-fed mice treated with oleacein. Collectively, our findings indicate that protection against HFD-induced adiposity by oleacein in mice is mediated by the modulation of regulators of adipogenesis. Protection against HFD-induced obesity is effective in improving peripheral insulin sensitivity.

Mouse models can provide useful information to understand molecular mechanisms of human tumorigenesis. In this study, the conditional thyroid mutagenesis of Pten and Ras genes in the mouse, which induces very aggressive follicular carcinomas (FTCs), has been used to identify genes differentially expressed among human normal thyroid tissue (NT), follicular adenoma (FA), and FTC. Global gene expression of mouse FTC was compared with that of mouse normal thyroids: 911 genes were found deregulated ± 2-fold in FTC samples. Then the expression of 45 deregulated genes in mouse tumors was investigated by quantitative RT-PCR in a first cohort of human NT, FA, and FTC (discovery group). Five genes were found significantly down-regulated in FA and FTC compared with NT. However, 17 genes were found differentially expressed between FA and FTC: 5 and 12 genes were overexpressed and underexpressed in FTC vs FA, respectively. Finally, 7 gene products, selected from results obtained in the discovery group, were investigated in a second cohort of human tumors (validation group) by immunohistochemistry. Four proteins showed significant differences between FA and FTC (peroxisomal proliferator-activated receptor-γ, serum deprivation response protein, osteoglycin, and dipeptidase 1). Altogether our data indicate that the establishment of an enriched panel of molecular biomarkers using data coming from mouse thyroid tumors and validated in human specimens may help to set up a more valid platform to further improve diagnosis and prognosis of thyroid malignancies.

Objective: The aim of this review was to analyze the existing literature concerning the relationship between Hashimoto thyroiditis (HT) and vestibular dysfunction. Methods: We used electronic databases (PubMed, EMBASE, Cochrane Library) to search and collect all published articles about the association between HT and vestibular disorders. Results: Several observational and retrospective studies have postulated a relationship between thyroid autoimmunity and vestibular disorders. In most cases, an appropriate control group was lacking, and the impact of thyroid functional status could not precisely be established. In recent years, two well-designed prospective studies have provided convincing evidence that the association is not random. One article reported that patients with Meniere disease (MD) had a significantly higher prevalence of positive anti-thyroid autoantibody as compared to healthy controls. Moreover, more than half of MD patients had either positive anti-thyroid or non–organ-specific autoantibody titers, compared to less than 30% of both patients with unilateral vestibular paresis without cochlear involvement and healthy controls. Another study found that patients with benign paroxysmal positional vertigo (BPPV) had significantly higher serum thyroid-stimulating hormone and antithyroid autoantibody levels than healthy controls. Additionally, almost one-fifth of euthyroid patients with HT had signs of BPPV. Conclusion: The published results indicate that patients with MD or BPPV are potential candidates to also develop HT. Thus, in HT patients, the presence of even slight symptoms or signs potentially related to vestibular lesions should be carefully investigated. Abbreviations: AITD = autoimmune thyroid disease; BPPV = benign paroxysmal positional vertigo; EH = endolymphatic hydrops; HT = Hashimoto thyroiditis; L-T4 = L-thyroxine; MD = Meniere disease; PS = Pendred syndrome; Tg = thyroglobulin; TPO = thyroid peroxidase; TSH = thyroid-stimulating hormone

Context: Trends toward more conservative management of papillary thyroid cancer (PTC) diminish the primacy of serum thyroglobulin (Tg) assays as a posttreatment surveillance tool. Objective: To identify thyroid tumor-associated microRNAs (miRNAs) in the serum with potential for development as unique biomarkers of PTC recurrence. Methods: We measured expression of 754 miRNAs in serum samples collected from 11 patients with PTC before and 30 days after thyroidectomy. Major candidates were then re-evaluated by absolute quantitative polymerase chain reaction analysis in an independent cohort of patients with PTC (n = 44) or benign nodules and 20 healthy controls (HCs). The 2 miRNAs most significantly associated with thyroid tumors were then assessed in matched serum samples (before and 30 days and 1 to 2 years after surgery) from the 20 PTC patients with complete follow-up datasets and results correlated with American Thyroid Association (ATA) responses to therapy. Results: Eight miRNAs (miR-221-3p, miR-222-3p, miR-146a-5p, miR-24-3p, miR-146b-5p, miR-191-5p, miR-103a-3p, and miR-28-3p) displayed levels in prethyroidectomy serum samples from patients with PTC that significantly exceeded those measured after thyroidectomy and those found in samples from HCs. The 2 most promising candidates—miR-146a-5p and miR-221-3p —were further analyzed in the 20 PTC patients mentioned earlier. Serum levels of both miRNAs after 1 to 2 years of follow-up were consistent with ATA responses to therapy in all patients, including 2 with structural evidence of disease whose Tg assays remained negative (, Precis: Analysis of miRNA levels in pre- and postoperative serum samples from PTC patients reveals possible associations between postoperative changes in miR-146a-5p and miR-221-3p and clinical outcome.

An increased incidence of obesity is registered worldwide, and its association with insulin resistance and type 2 diabetes is closely related with increased morbidity and mortality for cardiovascular diseases. A major clinical problem in the management of obesity is the non-adherence or low adherence of patients to a hypo-caloric dietetic restriction. In this study we evaluated in obese mice the effects on insulin sensitivity of shifting from high-calorie foods to normal diet. Male C57BL/6JolaHsd mice (n=20) were fed with high fat diet for a 24 weeks period. Afterwards, body weight, energy and food intake were measured in all animals, together with parameters of insulin sensitivity by homeostatic model assessment of insulin resistance and plasma glucose levels in response to insulin administration. Moreover, in half of these mice, Glut4 mRNA levels were measured in muscle at the end of the high fat treatment, whereas the rest of the animals (n=10) were shifted to normocaloric diet for 10 weeks, after which the same analyses were carried out. A significant reduction of body weight was found after the transition from high to normal fat diet, and this decrease correlated well with an improvement in insulin sensitivity. In fact, we found a reduction in serum insulin levels and the recovery of insulin responsiveness in terms of glucose disposal measured by insulin tolerance test and Glut4 mRNA and protein expression. These results indicate that obesity related insulin resistance may be rescued by shifting from high fat diet to normocaloric diet.

Testicular cancer is the most frequent cancer in young men. The large majority of patients have a good prognosis, but in a small group of tumors, the current treatments are not effective. Radioiodine is routinely used in the treatment of thyroid cancer and is currently investigated as a potential therapeutic tool even for extra-thyroid tumors able to concentrate this radioisotope. Expression of Na+/I− symporter (NIS (SLC5A5)), the glycoprotein responsible for iodide transport, has been demonstrated in normal testicular tissue. In this study, we analyzed NIS expression in a large series of testicular carcinomas. Our retrospective series included 107 patients operated for testicular tumors: 98 typical seminomas, six embryonal carcinomas, one mixed embryonal choriocarcinoma, and two Leydig cells tumors. Expression and regulation of NIS mRNA and protein levels were also investigated in human embryonal testicular carcinoma cells (NTERA) by real-time RT-PCR and western blotting respectively. Immunohistochemical analysis showed the presence of NIS in the large majority of seminomas (90/98) and embryonal carcinomas (5/7) of the testis but not in Leydig cell carcinomas. Expression of NIS protein was significantly associated with lymphovascular invasion. In NTERA cells treated with the histone deacetylase inhibitors SAHA and valproic acid, a significant increase in NIS mRNA (about 60- and 30-fold vs control, PP

Comprehension of the regulatory mechanism involved in the sodium iodide symporter (NIS) expression is of great relevance for thyroid cancer. In fact, restoration of NIS expression would be a strategy to treat undifferentiated thyroid cancer. Previous in vitro findings suggest that the cyclic AMP-response element (CRE) modulator (CREM) is involved in control of NIS expression. In this work, we examined the expression of CREM in a series of thyroid cancer tissues and its action on NIS promoter in human thyroid cancer cells.Expression of mRNA levels for CREM, PAX8 and NIS was measured by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in 6 normal thyroid tissues, 22 papillary, 12 follicular and 4 anaplastic thyroid cancers. The effect of CREM on transcriptional activity of the NIS promoter was investigated by transient transfection of human thyroid cell lines.Compared to normal tissues, NIS and PAX8 mRNA levels were significantly reduced in all types of thyroid cancer. As expected, the maximal decrease was detected in anaplastic thyroid cancer. Conversely, CREM mRNA levels were increased in all types of thyroid cancer, reaching statistical significance for follicular and anaplastic thyroid carcinoma (p=0.0157 and 0.0045, respectively). Transfection experiments showed an inhibitory effect of CREM on NIS promoter activity in various thyroid cancer cell lines.These data demonstrate that CREM expression is increased in thyroid cancer tissue and may play a role in the downregulation of NIS expression in thyroid cancer acting at the transcriptional level.

Background: Agents capable of increasing radioiodine concentration by stimulating the sodium/iodide symporter (NIS) expression have been extensively investigated for the treatment of certain well-differentiated breast cancers. Aim: In this study, we analyzed the regulation of the NIS and lactoperoxidase (LPO) gene expression in 4 different human breast cancer cell lines, representative of different histotypes of breast cancer. Methods: MCF-7, T-47D, MDA-MB231, and HCC-1937 (the latter carrying the BRCA-1 mutation) were exposed to different stimulators and the levels of NIS and LPO mRNA measured by a quantitative RT-PCR. Results: AII-trans-Retinoic Acid (RA), Dexamethasone (DEX), Trichostatin A (TSA), and Sodium Butyrate (NaB) induced the expression of NIS mRNA in MCF-7 and T-47D cell lines, whereas HCC-1937 and MBA-MB231 were slightly responsive only to the histone-deacetylase inhibitors TSA and NaB. Minor stimulatory effects were detected on LPO mRNA in MCF-7 and T-47D treated with TSA and NaB or RA only in MCF-7, while no effect was detectable in the other two cell lines. Conclusions: These data indicate that retinoic acid, alone or in combination with DEX, as well as HDAC-inhibitors are very promising agents for a radioiodine-based therapy in a large spectrum of breast cancers, including neoplasms from both basal and ductal cells, especially for the well-differentiated estrogen-dependent tumors. Other molecules or other drug combinations should be tested to extend the same strategy to the less differentiated and more aggressive tumor cells, including those carrying the BRCA mutation.

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.

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.

Context: RET mutation analysis provides useful information on the clinical outcome of medullary thyroid carcinomas (MTCs) and the risk of disease in the family members. Objective: The objective of this study was to document genotype-phenotype relationships in an Italian family with a novel RET mutation. Design/Setting: RET gene alterations were investigated in a patient with unifocal MTC and her relatives. The identified mutation was subjected to in vitro functional testing. Patients: Patients included a female proband who developed MTC at age 60, her five children, and three grandchildren. Main Outcome Measures: DNA extracted from the blood and the proband’s tumor were analyzed for RET alterations. The transforming potential and mitogenic properties of the identified mutation were investigated. Results: A novel heterozygous germline RET mutation at codon 777 (AAC→AGC, N→S) (RET/N777S) was identified in the proband and three of her relatives. Two of the latter presented thyroid nodules, but none had MTC o...

We report a case of a male patient thyroidectomized for follicular thyroid carcinoma and presenting extremely elevated serum thyrotropin levels under L-T4 suppressive therapy. Administration of L-T3 in increasing amounts resulted in a significant decrease of serum TSH levels. The nature of the possible molecular defects underlying this unusual condition and pitfalls arising from the failure of L-T4 therapy to inhibit TSH secretion in a patient in post-surgical follow-up for follicular carcinoma are discussed.

Pax proteins are transcriptional regulators that control a variety of developmental decisions in vertebrates. During development, the paired-box gene 8 (PAX8) is expressed in the thyroid, kidney, and several areas of the central nervous system. It is also expressed in the adult thyroid gland, in which it mediates TSH-induced modulation of the expression of important genes, such as those encoding thyroglobulin, thyroperoxidase, and the sodium/iodide symporter (NIS). Thus far, placental expression of PAX8 has been described only in mice. In the present study, we show that PAX8 is also expressed in the human placenta at term. In an in vitro model of placental cancer, the JAR choriocarcinoma cell line, human chorionic gonadotropin (hCG) increased levels of PAX8 mRNA and protein, and gel retardation assays indicated that the up-regulation of PAX8 protein expression is associated with an increase in its DNA-binding activity. The effects of hCG were mimicked by forskolin, indicating that they are cAMP dependent. Levels of mRNA for the Wilms' tumor 1 (WT1) and NIS genes were increased in JAR cells by hCG treatment, whereas overexpression of PAX8 increased only levels of WT1 mRNA. In cells transfected with PAX8-specific small interfering RNA, the stimulatory effects of hCG on WT1 mRNA levels were abolished, but hormonal enhancement of NIS mRNA levels was unchanged. These findings indicate that, in JAR cells, hCG activates a cAMP-dependent pathway that can up-regulate WT1 expression through PAX8.

Sodium/iodide symporter (NIS) expression has recently been described in human breast cancer, with emphasis on its potential exploitation for the treatment of these tumors with radioiodine. In this study, we analyzed the regulation of NIS expression and function in the MCF-7 human breast cancer cell line. Cell exposure to insulin, IGF-I, IGF-II, or prolactin induced significant increases in 125I uptake and the expression of both NIS mRNA and NIS protein. The latter increases were evident after 6 and 12 h of hormonal stimulation, respectively. In immunocytochemistry studies, NIS was detected mainly in the plasma membrane of MCF-7 cells. A low but significant increase in iodide uptake was produced by treatment with activators of the adenylyl cyclase (cAMP) or protein kinase C pathways. Our study demonstrates that: 1) MCF-7 breast cancer cells are capable of active iodide transport that can be stimulated by insulin, IGF-I, IGF-II, or prolactin; 2) both NIS transcript and protein are expressed in these cells, and this expression is also hormonally stimulated; and 3) MCF-7 iodide transport and NIS expression may be influenced by the activation of cAMP or protein kinase C-dependent signaling. These findings increase our understanding of the molecular mechanisms that regulate NIS expression in breast cancer cells, information that is fundamental for future research aimed at the development of targeted radioiodide treatment for this type of cancer.

Hyperfunctioning thyroid nodules are characterized by the presence of spontaneous somatic mutations responsible for constitutive activation of the cAMP pathway. However, alterations affecting other elements of the cAMP signaling system may counteract the effects of the mutations. In this study, the expression of the adenylyl cyclase (AC) types III and VI was investigated by Western blot in 18 hyperfunctioning thyroid nodules; in 12 samples, we also assessed the presence of TSH receptor (TSHR) or gsp mutations and levels of AC VI and III mRNA. We found that the expression of nodular AC VI (but not AC III) was significantly lower (85.1% of normal, P=0.014) than the expression of both adenylyl cycles types of perinodular tissue from the same patients. Slightly, but not significant differences were detected in nodules with or without mutations and AC protein levels generally showed correlation with the levels of the transcripts detected by RT-PCR. In addition, AC III and AC VI expression levels within a given nodule were characterized by a significant positive correlation. These findings indicate that a diminished expression of AC type VI may be part of the mechanisms occurring in the hyperfunctioning nodules, independently of the presence of TSHR or gsp mutations, which influence the resulting phenotype.

Apurinic/apyrimidinic endonuclease APE/Ref-1 is a multifunctional protein provided with DNA repair, transcription-factor regulation and anti-apoptotic activities. We have previously reported that, in thyroid cells, TSH regulates both the synthesis and nuclear translocation of APE/Ref-1. We have also shown that nuclear levels of this protein are reduced both in thyroid carcinoma tissues and cell lines. In the present study, APE/Ref-1 expression and cellular localization were analysed by Western blot in hyperfunctioning thyroid nodules from patients with toxic adenoma and/or toxic multinodular goiter. The total content of APE/Ref-1 protein was increased in the majority of the hyperfunctioning tissues with respect to normal adjacent tissue. There was also an increase in the nuclear levels of APE/Ref-1, suggesting enhanced cytoplasm-to-nucleus translocation of the protein in addition to its increased rate of synthesis. These results demonstrate that the phenomenon of nuclear translocation of APE/Ref-1 hypothesized on the basis of cell culture experiments does actually occur in vivo. Together with previous observations in thyroid carcinomas and tumoral cell lines, our findings suggest a two-stage model of APE/Ref-1 behaviour during malignant thyrocyte transformation: an early stage characterized by simple hyperplasia and upregulation of APE/Ref-1 in the nuclear compartment of the cell and a later stage in which nuclear levels of the protein drop to below-normal levels as the cell becomes progressively undifferentiated.

Homeobox genes are involved in neoplastic transformation of both epithelial and hemopoietic tissues. The divergent homeobox gene HEX is expressed in the anterior visceral endoderm during early mouse development and in some adult tissues of endodermal origin, including liver and thyroid. Whereas a role in leukemyogenesis has been proposed already, few data are available on the involvement of HEX in human epithelial tumors. Herein, we analyzed HEX expression and subcellular localization in a series of 55 human thyroid tumors and in several tumoral cell lines. HEX mRNA was detected by RT-PCR either in normal tissues or in thyroid adenomas and differentiated (papillary and follicular) carcinomas. HEX mRNA was also expressed in most undifferentiated carcinomas. Subcellular localization of HEX protein was investigated by immunohistochemistry. In normal tissues and adenomas, HEX protein was present both in nucleus and cytoplasm. In contrast, both differentiated and undifferentiated carcinomas, as well as the tumoral cell lines investigated, showed HEX protein only in the cytoplasm. These findings suggest that regulation of HEX entry in the nucleus of thyrocytes may represent a critical step during human thyroid tumorigenesis. (J Clin Endocrinol Metab 87: 1376 –1383, 2002)

Antonino Belfiore*, Diego Russo2, Riccardo Vigneri3 and Sebastiano Filetti*§ *Dipartimento di Medicina Sperimentale e Clinica `G. Salvatore' and 2Dipartimento di Scienze Farmacobiologiche, University of Catanzaro `Magna Graecia', 88100 Catanzaro, Italy, 3Istituto di Medicina Interna, Malattie Endocrine e del Metabolismo, University of Catania, Ospedale Garibaldi, Catania, Italy and §Dipartimento di Scienze Cliniche, UniversitaA `La Sapienza', Roma, Italy

OBJECTIVE: To investigate the molecular mechanisms underlying the influence of alteration of iodine trapping on the prognosis of metastatic papillary thyroid carcinomas, focusing on the expression of the Na+/I(-) symporter (NIS). DESIGN: We evaluated the expression of the NIS gene in a series of 11 enlarged neck lymph-node metastases of papillary thyroid carcinomas, including four patients in whom an enlarged lymph node represented the first sign of the tumoral disease. Nine lymph nodes, either reactive or metastatic for non-thyroid tumors, were also investigated. METHODS: Expression of the NIS gene was evaluated by RT-PCR in material obtained by fine-needle aspiration biopsy. RESULTS: The NIS gene was expressed in eight (73%) of 11 differentiated thyroid cancer metastatic lymph nodes examined. Five of these metastatic lymph nodes were positive at the post-treatment total-body iodine-131 scan; in the other three, the total-body scan showed no uptake in the metastatic tissues, indicating an alteration downstream to the NIS mRNA synthesis causing the loss of iodide uptake. As expected, when the NIS mRNA expression was absent, total-body (131)I scan showed no uptake in the metastatic lymph nodes. CONCLUSIONS: Our study demonstrates that NIS gene expression may be absent in metastatic differentiated thyroid carcinomas and that different mechanisms, other than loss of NIS transcription, may also be involved in the loss of iodide uptake in metastatic thyroid cells. Study of NIS gene expression in the metastatic lymph nodes, therefore, may provide useful information in the management of patients with thyroid carcinoma.

Resistance to TSH is a syndrome due to reduced responsiveness of the thyroid gland to biologically active TSH. Inactivating mutations of the TSH receptor (TSH-R) have been detected in several cases of resistance to TSH, both partial and complete, sporadic and familial. In this study, we describe a family with the presence of resistance to TSH responsible for euthyroid hyperthyrotropinemia in two siblings from consanguineous parents. By direct sequencing of the TSH receptor gene, we identified a new mutation responsible for the substitution of an arginine with a cysteine at position 310, in the extracellular domain of the TSH-R. The mutation was homozygous in two brothers; heterozygous in both parents, an uncle, and an unaffected brother; and absent in the other unaffected brother. When stably transfected in Chinese hamster ovary cells, the Cys310 mutant TSH-R showed loss of response to TSH in terms of cAMP stimulation. However, a constitutive activity in terms of basal cAMP production was detected in the Cys310 mutant, compared with the wild-type TSH-R. Our data suggest that such a Cys310 TSH-R mutant may determine both the TSH resistance and the clinical euthyroidism detected in this family.

Expression of the Na+/I− symporter (NIS) gene was investigated by RT-PCR in a selected series of 26 primary thyroid carcinomas (19 papillary, 5 follicular, and 2 anaplastic). Fifteen follicular adenomas (11 “cold ” and 4 “hot” adenomas) were also studied. Five of 19 papillary thyroid cancer did not express NIS messenger ribonucleic acid (mRNA). In all but 1 follicular cancer, NIS transcript was fully detected. In anaplastic tissue, NIS mRNA was only barely detected in 1 case. All of the follicular thyroid adenomas except 1 expressed the NIS gene. In contrast, all tumors studied excluding the anaplastic histotype fully expressed thyroglobulin and thyroid peroxidase mRNA transcripts. In 2 patients, a lower expression (3- to 5-fold) of NIS mRNA was found in metastasis by dot blot analysis compared with those in both normal and primary neoplastic thyroid tissue. Four of 8 differentiated thyroid cancer patients selected for the presence of metastases with negative posttherapy 131I total body scan showed the lack of NIS gene expression in their primary cancer. This defect, at least in these cases, is a somatic and intrinsic lesion of the primary cancer cells and is not due to a dedifferentiation process in the metastatic tissue. The early detection of the loss of NIS gene expression in the primary cancer, therefore, may provide useful information for the management of differentiated thyroid cancer patients.

Medullary thyroid carcinoma (MTC) management requires determination of the sporadic or familial nature of the disease. RET proto-oncogene mutation analysis in the tumor tissue obtained at surgery and in the peripheral blood identifies somatic vs. germinal mutations. We now report a case of MTC in which a RET somatic mutation at codon 918 was detected in fine-needle aspiration specimens obtained from both the thyroid nodule and two enlarged neck lymph nodes but not in peripheral blood. Therefore, a diagnosis of sporadic MTC was made before surgery. Thus, this approach, by excluding preoperatively multiple endocrine neoplasia disease, permitted immediate thyroidectomy without search for pheochromocytoma. PCR-based genetic analysis in fine-needle aspiration biopsy specimens, therefore, preoperatively identifies genetic abnormalities at an early and easily manageable stage and may well contribute to the management strategy of MTC.

Thyroid carcinomas, even when well differentiated, usually appear as hypofunctioning at scintigraphy. We report a case of an aggressive insular thyroid carcinoma presenting as an autonomously functioning thyroid nodule and causing severe thyrotoxicosis. The tumor was metastatic to a cervical lymph node and both lungs. An activating mutation of the TSH receptor gene in both the primary tumor and the lymph node metastasis was found, due to a base substitution at codon 633 (normal guanine at position 1896 replaced by cytosine CAC for GAC causing aspartic acid substitution by histidine). Other known oncogenes (gsp, ras, PTC/ret, trk, met, and p53) were not involved. This is the first description of an activating TSH receptor mutation in a thyroid hyperfunctioning carcinoma in which an aggressive malignant phenotype coexisted with activation of the cAMP cascade and differentiated thyroid functions.

The presence of the sodium/iodide symporter (NIS) is the prerequisite for the use of the radioiodine in the treatment of thyroid cancer. Thus, stimulators of NIS expression and function are currently investigated in cellular models of various human malignancies, also including extrathyroid cancers. In this study, we analyzed the effects of the histone deacetylase inhibitors (HDACi), suberoylanilide hydroxamic acid (SAHA) and valproic acid (VPA), on NIS expression and function in rat Leydig testicular carcinoma cells (LC540). LC540 cells were exposed to SAHA 3 μM and VPA 3 mM (alone and in combination), and cell viability evaluated by MTT assay and cell counting, NIS mRNA and protein levels by using, respectively, real-time RT-PCR and western blotting. NIS function was evaluated by iodide uptake assay. We found that both HDACi were able to stimulate the transcription of NIS gene, but not its protein expression, while the association of SAHA and VPA increased both NIS transcript and protein levels, resulting in significant sixfold enhancement of radioiodine uptake capacity of LC540 cells. These data demonstrate the presence of an epigenetic control of NIS expression in Leydig tumor cells, suggesting the possibility to use the combination of these two HDACi for a radioiodine-based treatment of these malignancies.

Autonomously functioning thyroid nodules (AFTN) are known to receive an increased blood influx necessary to sustain their high rate of growth and hormone production. Here, we investigated the expression of hematic and lymphatic vases in a series of 20 AFTN compared with the contralateral non-tumor tissues of the same patients, and the transcript levels of proteins involved in the control of vascular proliferation, including the vascular endothelial growth factor (VEGF) and platelet-derived growth factors (PDGF) and their receptors and the endothelial nitric oxide synthase (eNOS). In parallel, the expression of the differentiation markers sodium/iodide symporter (NIS), thyroperoxidase (TPO), thyroglobulin (Tg), and TSH receptor (TSHR) was also investigated. The data were further analyzed comparing subgroups of tumors with or without mutations in the TSHR gene. Analysis by means of CD31 and D2-40 immunostaining showed in AFTN an increased number of hematic, but not lymphatic, vessels in parallel with an enhanced proliferation rate shown by increased Ki67 staining. Quantitative RT-PCR analysis revealed an increase of VEGF, VEGFR1 and 2, PDGF-A, PDGF-B, and eNOS expression in tumor versus normal tissues. Also, higher transcript levels of NIS, TPO, and Tg were detected. Comparison of the two subgroups of samples revealed only few differences in the expression of the genes examined. In conclusion, these data demonstrate an increased expression of angiogenesis-related factors associated with an enhanced proliferation of hematic, but not lymphatic, vessels in AFTNs. In this context, the presence of TSHR mutations may only slightly influence the expression of pro-angiogenic growth factors.

SummaryContext Germline mutations in four genes (RET, VHL, SDHB and SDHD) are detected in about 17% of patients with apparently sporadic pheochromocytoma. Thus, genetic screening of all patients with this disease is suggested for a rational diagnostic approach and management. Objective To report the clinical, biochemical and genetic analysis of three unrelated patients affected by pheochromocytoma. Design and patients All the coding regions and exon–intron boundaries of RET, VHL, SDHB and SDHD genes were sequenced in three unrelated patients with intra-adrenal pheochromocytoma: a 17-year-old girl, a 15-year-old boy and a 73-year-old man. The family history of all three cases was negative for von Hippel–Lindau lesions or other types of endocrine tumours. Structural modelling of the VHL protein was then performed. Results We identified a novel germline VHL gene point mutation, a G to A nucleotide substitution in exon 3, leading to an aspartate to asparagine amino acid change in codon 197 (D197N). No mutations were found in RET, SDHB and SDHD genes. Structural modelling of the VHL protein suggests that the D197N mutation could have a functional role. Conclusions Our study expands the number of VHL gene known mutations and indicates the usefulness of performing the genetic analysis in all patients with apparently sporadic pheochromocytoma.

Sunitinib is a multikinase inhibitor approved for use in some human solid malignancies, including renal clear cell and gastrointestinal stromal cancer, and under investigation for many other neoplasias. In many preclinical cancer models sunitinib has shown anti-angiogenic and antitumor effects, acting mainly by inhibiting the activity of pro-angiogenic growth factor receptors. However, a percentage of tumors develop resistance to this treatment. The aim of this study was to identify novel potential molecular targets for the non- responsive tumors. The effects of sunitinib were investigated in xenograft tumors obtained by injecting HEK293 cells into NOD-SCID mice, focusing on the activity of growth-regulating pathways involved in tumorigenesis. During 11 days of oral administration of sunitinib (40 mg/kg/day), the growth of tumors was monitored by measuring the mass volume by a caliper. At the end of the treatment, tumor specimens were histologically examined for microvessel density (MVD) and presence of necrosis, and the phosphorylation of ERK and Akt was analyzed in protein extracts by Western blotting. Moreover, the mRNA levels of VEGF and its receptor genes were measured by quantitative RT-PCR. Treatment with sunitinib elicited a clear reduction of the tumor growth, associated with a reduction of MVD, correlated with an increased number of necrotic cells. In contrast, the levels of phosphorylated Akt and ERK proteins were similar in treated and non-treated animals. The VEGF and VEGFR-1 and 2 transcripts were not affected by sunitinib treatment. In conclusion, these findings confirm the anti-angiogenic action as the major effect of sunitinib against tumor growth. In contrast, other important growth regulatory pathways involved in malignant trans-formation, such as the ERK-MAPK and Akt/mTOR pathways are not affected by such a treatment, suggesting the use of specific inhibitors of these pathways as valid candidates for combinatorial therapies in sunitinib-resistant malignancies.

Intrathyroidal medullary thyroid carcinoma (MTC) can generally be cured by surgery, but distant metastases are often already present at diagnosis.Currently, there is no effective treatment for metastatic MTC. In these cases, consensus treatment guidelines explicitly recommend new experimental drugs. Several kinase inhibitors are now being tested for treatment of MTC in clinical trials and XL184, an oral, small-molecule multi-kinase inhibitor, seems to be one of the most promising of these compounds.We review preliminary data on the safety and efficacy of XL184 in metastatic MTC based on an extensive search of the literature, which included published articles, abstracts and website information. In particular,the review focuses on the rationale for using XL184 in advanced MTC. The compound has been specifically designed to target multiple signaling pathways,and this is expected to produce synergistic antitumor effects superior to those achieved by single-kinase inhibition. Preliminary results from the Phase I study of XL184 seem to support this hypothesis.Multiple receptor tyrosine kinases (RTKs) are concomitantly activated in the same tumor. The blockade of a single RTK may engage compensatory signaling that maintains cell growth. Targeting multiple kinases might overcome both intrinsic and acquired resistance to antitumoral drugs.

Administration of radioiodine (I(131)) is currently exploited for both diagnostic and therapeutic treatment of thyroid cancer. Few data are available on the sodium/iodide symporter (NIS) expression in human testis, a particular important prerequisite to predict radioiodine accumulation in the gonads of males with thyroid cancer exposed to such a treatment. In this study, we analyzed the expression of NIS in mouse, rat and human normal testis in different stages of development. By using a quantitative RT-PCR, Western blot and immunohistochemical analysis, NIS mRNA and protein were measured in both fetal and adult testicular tissues. NIS transcript was detected in both fetal and adult testis, although its expression levels were approximately 10-fold less than in thyroid gland. Western blot analysis and immunohistochemistry showed the presence of NIS protein in germinal and Leydig cells, but not in Sertoli cells with prevalent expression in the cytosol compartment of the cells. Our study demonstrates that NIS transcript and protein are expressed in normal testis. Further studies will demonstrate whether it may act as the transporter of radioiodine in normal testis of male patients with thyroid cancer.

ObjectiveTyrosine kinase inhibitors (TKIs) are evaluated for treatment of radioiodine refractory thyroid cancer. Their effects in this setting are based on blockade of proangiogenic signaling mediated by receptors for vascular endothelial growth factors (VEGFs) and platelet-derived growth factors (PDGF). Most TKIs also block other cancer-relevant kinases, such as B-type Raf kinase (BRAF), which are constitutively activated in approximately half of papillary thyroid carcinomas (PTCs), but the impact of these effects is not clear.DesignThe aim of our study was to investigate the impact of BRAFV600E on proangiogenic gene expression and microvascular features of PTCs.MethodsmRNA levels for VEGFA, VEGF receptors, and coreceptors (VEGFRs 1, 2, and 3, neuropilin-1), and PDGF receptor β (PDGFRβ or PDGFRB) were measured with real-time PCR in BRAFV600E (n=55) and wild-type BRAF (BRAF-wt; n=35) PTCs. VEGF and VEGFR protein expression and microvessel densities (MVD) and lymphatic vessel densities (LVDs) were assessed by immunohistochemistry in 22 of the 90 PTCs (including 11 BRAFV600E cases). Angiogenic gene expression was also studied in vitro after induction/silencing of the BRAFV600E mutation in thyrocyte lines.ResultsTranscript levels of proangiogenic factors were significantly lower in BRAFV600E PTCs versus BRAF-wt PTCs (PVEGFA mRNA levels in thyroid cell lines decreased when BRAFV600E mutation was induced (P=0.01) and increased when it was silenced (P=0.01).ConclusionsCompared with BRAF-wt PTCs, those harboring BRAFV600E exhibit downregulated VEGFA, VEGFR, and PDGFRβ expression, suggesting that the presence of BRAF mutation does not imply a stronger prediction of response to drugs targeting VEGF and PDGFB signaling pathways.

Levothyroxine (L-T4)-based suppression of thyrotropin (TSH) secretion is widely used to prevent the growth of benign thyroid nodules, although the effectiveness of this approach has been demonstrated only in a subset of patients. In this study, we analyzed the in vivo effects of L-T4-mediated TSH suppression on elements of insulin/IGF-1-dependent growth-regulating pathways in tissues from patients with benign thyroid nodules. Nodular and non-nodular tissue specimens were collected from 63 patients undergoing thyroidectomy. 32 had received preoperative TSH suppressive therapy with TSH levels consistently below 0.5 mU/l (L-T4 group). TSH suppression had not been used in the other 31, and their TSH levels were normal (0.8-4 mU/l (control group). Quantitative RT-PCR was used to measure mRNA levels for TSH receptor, IGF1, IGF-1 receptor, insulin receptor, insulin receptor substrate 1 in nodular and non-nodular tissues from the 2 groups. Akt and phosphorylated Akt protein levels were detected by Western blot. Mean levels of mRNA for all genes tested were similar in the 2 groups, in both nodular and non-nodular tissues. The 2 groups were also similar in terms of phosphorylated Akt protein levels (measured by densitometric scan in 10 randomly selected nodules from each group). This is the first demonstration based on the study of human thyroid tissues that TSH suppression does not affect the expression of components of the insulin/IGF-1-dependent signaling pathways regulating thyrocyte growth. This may explain the lack of effectiveness of TSH-suppressive therapy in a substantial percentage of benign thyroid nodules.

Context In multiple endocrine neoplasia (MEN), rearranged during transfection (RET), gene testing has been extensively exploited to characterize tumour aggressiveness and optimize the diagnostic and clinical management. Objective To report the underlying genetic alterations in an unusual case of MEN type 2 (MEN-2A). Design and patient Occult medullary thyroid carcinoma (MTC) was diagnosed in a 44-year-old man who had presented with unilateral phaeochromcytoma. DNA extracted from the blood and tumour tissues was analysed for mutations in RET. The transforming potential and mitogenic properties of the identified RET mutation were investigated. Results The patient carried a novel heterozygous germ-line RET mutation in exon 5 (Val292Met, GTG>ATG) (V292M/RET) with no evidence of additional somatic alterations. The mutation maps to the third cadherin-like domain of RET, which is usually not included in RET screening. Interestingly, MTC with concomitant phaeochromcytoma has never been associated with a RET mutation involving the extracellular cadherin-like domain. V292M/RET was absent in the only two relatives examined. In vitro assays indicate that the mutant has low-grade transforming potential. Conclusions Complete characterization and classification of all novel RET mutations are essential for extending genetic analysis in clinical practice. Our findings suggest that: (i) in all MEN-2 patients negative for RET hot-spot mutations, testing should be extended to all coding regions of the gene and (ii) the newly identified V292M/RET mutation is characterized by relatively weak in vitro transforming ability.

Nucleophosmin (NPM) is a protein that contributes to several cell functions. Depending on the context, it can act as an oncogene or tumor suppressor. No data are available on NPM expression in thyroid cells. In this work, we analyzed both NPM mRNA and protein levels in a series of human thyroid tumor tissues and cell lines. By using immunohistochemistry, NPM overexpression was detected in papillary, follicular, undifferentiated thyroid cancer, and also in follicular benign adenomas, indicating it as an early event during thyroid tumorigenesis. In contrast, various levels of NPM mRNA levels as detected by quantitative RT-PCR were observed in tumor tissues, suggesting a dissociation between protein and transcript expression. The same behavior was observed in the normal thyroid FRTL5 cell lines. In these cells, a positive correlation between NPM protein levels, but not mRNA, and proliferation state was detected. By using thyroid tumor cell lines, we demonstrated that such a post-mRNA regulation may depend on NPM binding to p-Akt, whose levels were found to be increased in the tumor cells, in parallel with reduction of PTEN. In conclusion, our present data demonstrate for the first time that nucleophosmin is overexpressed in thyroid tumors, as an early event of thyroid tumorigenesis. It seems as a result of a dysregulation occurring at protein and not transcriptional level related to an increase of p-Akt levels of transformed thyrocytes.

Pretreatment of cultured human thyroid cells with trypsin decreased the cAMP response to bovine TSH (bTSH) (by 50-60%). In striking contrast, in trypsin treated cells the cAMP stimulation by both human TSH (hTSH) and thyroid-stimulating antibodies (TSab) was unimpaired, indicating a similar behavior for these two stimulators. The effect of trypsin on inhibiting cAMP stimulation by bTSH was: 1) dose dependent; 2) present at a trypsin concentration as low as 3.3 mg/L; 3) fully reversible within 24 h after removal of the enzyme. In accordance with the altered biological activity in human thyroid cells exposed to trypsin the binding of labeled bTSH was reduced (about 40%). On the contrary, in the same cells, the binding of labeled human TSH was enhanced (about 3-fold). The cAMP response to cholera toxin and forskolin was unaffected in trypsin treated cells, indicating that the tryptic treatment did not alter any other component of the adenylate cyclase complex. The medium obtained from trypsin-treated human thyroid cells was able to neutralize the biological activity of bTSH but not that of hTSH or TSab. Our study demonstrates that in human thyroid cells: 1) trypsin impaires bovine, but not human TSH or TSab biological activity; 2) bovine and human TSH may bind to different components of the TSH receptor.