First Evidence of Mineralocorticoid Receptor Gene and Protein Expression in Rat and Human Thyroid Tissues and Cell Cultures.

Aldosterone (Aldo) exerts its action through binding with the mineralocorticoid receptor (MR). Clinically, a link between primary aldosteronism (PA) and thyroid diseases has been hypothesised. However, the presence and activity of MR on the thyroid have not yet been demonstrated. We investigated the gene/protein expression and activation of MR in primary thyroid cell cultures (normal rat thyroid [FRTL-5] and human papillary thyroid cancer [PTC] cell lines, BCPAP and K1) through qRT-PCR analysis, immunofluorescence, and confocal microscopy. We also studied the effects of Aldo on thyroid-specific and inflammation genes in vitro. Paired human normal and neoplastic thyroid tissues were also studied. We demonstrated both gene and protein expression and activation of MR in normal rat thyroid and human PTC lines. Incubation with Aldo induced an acute increase in IL-6 expression in both the FRTL-5 and BCPAP lines, which was antagonised by spironolactone, and an acute and late upregulation of thyroid-specific genes in FRTL-5. MR was also expressed at both gene and protein levels in normal human thyroid tissues and in PTC, with a progressive decline during neoplastic tumourigenesis, particularly in more aggressive histotypes. We present the first evidence of MR gene and protein expression in both normal and pathological thyroid cells and tissues. We have shown that MR is present and functionally activated in thyroid tissue. Binding of Aldo to MR induces the expression of inflammatory and thyroid-specific genes, and the thyroid may thus be considered a novel mineralocorticoid target tissue.

Tumor Grade and Molecular Characteristics Associated with Survival in Sporadic Medullary Thyroid Carcinoma.

Background: The International Medullary Thyroid Carcinoma Grading System (IMTCGS) divides medullary thyroid carcinoma (MTC) into two categories, high- and low-grade tumors, which has a profound impact on patient outcomes. The aim of this study was to explore the association between IMTCGS grading, clinical data, and molecular status in sporadic MTC. Methods: A retrospective cohort study was performed on consecutive sporadic MTCs from patients undergoing initial surgery between January 2000 and January 2022 at the Padua Endocrine Surgery Unit. Clinical, pathological, and follow-up data were collected, tumors were graded, and somatic mutations of RET and RAS genes were analyzed. Patient outcomes were based on Ct levels and MTC-related deaths. Survival analyses were carried out employing the Kaplan-Meier method and the log-rank test. A Cox proportional hazard regression model was employed for multivariable survival analysis with the following covariates: somatic RET mutation, MTC stage at diagnosis, sex, age at diagnosis, and IMTCGS grade. Results: We included 141 consecutive sporadic MTCs. The median follow-up was 80.0 months (interquartile ranges: 41.5-122.5 months). Seventeen patients (12.1%) died from disease-related causes. 107/141 (76.9%) were classified as low-grade tumors, 32/141 (23.1%) as high-grade. Patients carrying a RET mutation had more aggressive features and shorter disease-specific survival (DSS) (p = 0.001) and were more frequently classified high-grade than low-grade MTC (p < 0.001). At multivariable survival analysis, only IMTCGS grading was independently associated with DSS (hazard ratio 8.8 [confidence interval: 2.7-28.3], p = 0.005). RET mutations, in particular RET-M918T, were more frequent in high-grade than in low-grade MTC (68.8% vs. 29.4% mutated in RET, 46.9% vs. 12.7% mutated in RET-M918T; p < 0.001). None of the high-grade tumors was mutated in the RAS gene, but the mutation was present in 11.8% of low-grade tumors. Conclusions: IMTCGS grading was associated with DSS independently of other clinical, pathological, and molecular factors. Moreover, MTC grading was associated with RET and RAS patterns, which explains, at least in part, the molecular basis of the aggressive behavior of high-grade MTC.

Circulating miR-146a predicts glucocorticoid response in thyroid eye disease.

Objective: Thyroid eye disease (TED) is an immune-mediated disorder of the eye. Intravenous glucocorticoid (GC) is the first-line treatment for patients with active moderate-to-severe TED. However, the response rate is between 50% and 80%. There are still no simple and reliable markers of responsiveness to GC therapy. We aimed to explore the possible role of miR-146a and miR-21 as predictors of responsiveness to GC treatment in TED. Methods: We carried out a prospective longitudinal study on 30 consecutive adult patients with active moderate-to-severe TED and eligible for GC therapy. All patients received the standard GC treatment with methylprednisolone i.v. In cases of progressive worsening of Gorman Score for diplopia or with duction restriction <30° in at least two consecutive controls, patients also underwent orbital radiotherapy. Response to GC treatment was defined as a decrease of two or more points in the clinical activity score (CAS) or CAS <4/10 at 24 weeks. Circulating miRNAs were extracted from patients' serum and quantified by real-time PCR. Results: Twenty-three (77%) patients responded to GC. Thyroid surgery, higher CAS, greater proptosis and higher pre-treatment circulating levels of miR-146a emerged as predictive factors of responsiveness to GC. A ROC analysis revealed that miR-146a could predict responsiveness to GC with a positive predictive value of 100%. Conclusion: This is the first study investigating the role of pre-treatment circulating miR-21 and miR-146a to predict responsiveness to GC in TED. miR-146a emerged as a simple, objective, new marker of GC sensitivity that could be used to avoid ineffective administration of GC therapy to TED patients.

Effects of Handroanthus impetiginosus (Mart. ex DC.) Mattos extract on inflammatory, immune, atherogenic profile and differentiation in THP-1 cell line.

Handroanthus impetiginosus (Mart. ex DC.) Mattos is a plant from Central-South America that possesses different pharmacological activities. Plant extract was tested in THP-1 cell model, a human cell line used to study monocyte/macrophage functions. First, the plant effects on cell viability were evaluated, demonstrating no harmful consequences even at the higher concentrations (200 µg/ml). Thus, anti-inflammatory activity was investigated in gene and protein expression by RT-qPCR and ELISA methods, resulting in a reduction of pro-inflammatory cytokines after Handroanthus impetiginosus treatment. Similarly, NF-kB nuclear translocation was decreased according to confocal images and ImageStream X -analysis. Subsequently, in macrophage differentiated THP-1, CD36 mRNA and protein expression was inhibited in a concentration-dependent manner together with cell morphology changes during treatment. In addition, modified LDL-derived cholesterol uptake by THP-1 cells was reduced after plant extract incubation. Handroanthus impetiginosus showed anti-inflammatory and immunomodulating properties that may pave the way for future characterization in higher models.

Validation of miRNAs as diagnostic and prognostic biomarkers, and possible therapeutic targets in medullary thyroid cancers.

Introduction: Medullary thyroid cancer (MTC) is a rare type of neuroendocrine tumor that produces a hormone called calcitonin (CT). Thyroidectomy is the preferred treatment for MTC, as chemotherapy has been shown to have limited effectiveness. Targeted therapy approaches are currently being used for patients with advanced, metastatic MTC. Several studies have identified microRNAs, including miR-21, as playing a role in the development of MTC. Programmed cell death 4 (PDCD4) is a tumor suppressor gene that is an important target of miR-21. Our previous research has shown that high levels of miR-21 are associated with low PDCD4 nuclear scores and high CT levels. The aim of this study was to investigate the potential of this pathway as a novel therapeutic target for MTC. Methods: We used a specific process to silence miR-21 in two human MTC cell lines. We studied the effect of this anti-miRNA process alone and in combination with cabozantinib and vandetanib, two drugs used in targeted therapy for MTC. We analyzed the effect of miR-21 silencing on cell viability, PDCD4 and CT expression, phosphorylation pathways, cell migration, cell cycle, and apoptosis. Results: Silencing miR-21 alone resulted in a reduction of cell viability and an increase in PDCD4 levels at both mRNA and protein levels. It also led to a reduction in CT expression at both mRNA and secretion levels. When combined with cabozantinib and vandetanib, miR-21 silencing did not affect cell cycle or migration but was able to enhance apoptosis. Conclusion: Silencing miR-21, although not showing synergistic activity with TKIs (tyrosine kinase inhibitors), represents a potential alternative worth exploring as a therapeutic target for MTC.

The role of procalcitonin in the follow-up of medullary thyroid cancer.

Objective: Calcitonin (Ct) represents the most important biochemical marker of medullary thyroid cancer (MTC), but has certain limits. We analyzed the performance of procalcitonin (ProCt) in follow-up MTC patients. Methods: In this monocentric and retrospective study, we consecutively obtained ProCt and Ct values from all MTC patients that we visited during the period from April 2021 to May 2022. Patients were defined as having structural evidence of disease (29/90, 32.2%) irrespective of Ct values or, in its absence, as not evident disease (NED) if Ct was ≤10 ng/L (47/90, 52.2%), or minimal residual disease if Ct was >10 ng/L (14/90, 15.6%). Results: Ct and ProCt values were highly correlated (r = 0.883, P < 0.01). Median ProCt values differed between NED, minimal residual disease, and structural disease, being 0.04 ng/mL, 0.26 ng/mL, and 1.98 ng/mL, respectively (P < 0.01). ProCt was undetectable (<0.04 ng/mL) in 40/47 (85.1%) of NED patients, in 3/14 (21.4%) patients with minimal residual disease and in none of the patients with a structural disease (P < 0.01). Among the 11 patients with detectable but ≤10 ng/L Ct and undetectable ProCt values, none had a structural disease. The most accurate cut-off of ProCt to distinguish between the presence or absence of a structural disease was >0.12 ng/mL (P < 0.01, area under the curve: 0.963), with the following sensitivity, specificity, positive predictive value, and negative predictive value (NPV): 100%, 83.61%, 74.4%, and 100.0%. Conclusions: ProCt and Ct have a high correlation in MTC follow-up. ProCt may be useful as an adjunct to Ct, especially for its NPV concerning the structural disease.

The GIP/GIPR axis in medullary thyroid cancer: clinical and molecular findings.

The improper expression of glucose-dependent insulinotropic polypeptide receptor (GIPR) and the GIP/GIPR axis activation has been increasingly recognized in endocrine tumors, with a potential diagnostic and prognostic value. A high tumor-to-normal tissue ratio (T/N ratio) of GIPR was reported both in humans' and in rats' medullary thyroid cancer (MTC), suggesting a direct link between the neoplastic transformation and the mechanism of receptor overexpression. In this study, we evaluated the potential diagnostic and prognostic significance of GIPR expression in a large cohort of MTC patients by correlating GIPR mRNA steady-state levels to clinical phenotypes. The molecular effect of GIP/GIPR axis stimulation in MTC-derived cells was also determined. We detected GIPR expression in ~80% of tumor specimens, especially in sporadic, larger, advanced-stage cancers with higher Ki-67 values. GIPR stimulation induced cAMP elevation in MTC-derived cells and a small but significant fluctuation in Ca2+, both likely associated with increased calcitonin secretion. On the contrary, the effects on PI3K-Akt and MAPK-ERK1/2 signaling pathways were marginal. To conclude, our data confirm the high T/N GIPR ratio in MTC tumors and suggest that it may represent an index for the degree of advancement of the malignant process. We have also observed a functional coupling between GIP/GIPR axis and calcitonin secretion in MTC models. However, the molecular mechanisms underlying this process and the possible implication of GIP/GIPR axis activation in MTC diagnosis and prognosis need further evaluation.

Overexpression of miR-375 and L-type Amino Acid Transporter 1 in Pheochromocytoma and Their Molecular and Functional Implications.

Pheochromocytoma (Pheo) is a tumor derived from chromaffin cells. It can be studied using 18F-dihydroxyphenylalanine (DOPA)-positron emission tomography (PET) due to its overexpression of L-type amino acid transporters (LAT1 and LAT2). The oncogenic pathways involved are still poorly understood. This study examined the relationship between 18F-DOPA-PET uptake and LAT1 expression, and we explored the role of miR-375 and putative target genes. A consecutive series of 58 Pheo patients were retrospectively analyzed, performing 18F-DOPA-PET in 32/58 patients. Real-time quantitative PCR was used to assess the expression of LAT1, LAT2, phenylethanolamine N-methyltransferase (PNMT), miR-375, and the major components of the Hippo and Wingless/Integrated pathways. Principal germline mutations associated with hereditary Pheo were also studied. Pheo tissues had significantly higher LAT1, LAT2, and PNMT mRNA levels than normal adrenal tissues. MiR-375 was strongly overexpressed. Yes-associated protein 1 and tankyrase 1 were upregulated, while beta-catenin, axin2, monocarboxylate transporter 8, and Frizzled 8 were downregulated. A positive relationship was found between 18F-DOPA-PET SUV mean and LAT1 gene expression and for 24 h-urinary norepinephrine and LAT1. This is the first experimental evidence of 18F-DOPA uptake correlating with LAT1 overexpression. We also demonstrated miR-375 overexpression and downregulated (Wnt) signaling and identified the Hippo pathway as a new potentially oncogenic feature of Pheo.

Serum miR-375 for Diagnostic and Prognostic Purposes in Medullary Thyroid Carcinoma.

Purpose: Having previously demonstrated that tissue miR-375 expression in medullary thyroid carcinoma (MTC) tissues is linked to prognosis, the aim of this study was to assess the diagnostic and prognostic value of circulating miR-375 levels in MTC patients. Methods: A series of 68 patients with MTC was retrospectively retrieved and assessed in terms of their clinicopathological characteristics. MiR-375 levels were measured in all patients' presurgical blood samples. Both serum and tissue levels were tested prior to surgery in a subgroup of 57 patients. Serum miR-375 levels were also measured in serum from 49 patients with non-C-cell thyroid nodular diseases (non-CTN), 14 patients with pheochromocytoma, and 19 healthy controls. Results: Circulating miR-375 levels were 101 times higher in the serum of patients with MTC than in all other patients and controls, with no overlap (P < 0.01). No correlation emerged between serum and tissue miR-375 levels. Serum miR-375 levels were higher in MTC patients with N0 than in those with N1 disease (P = 0.01), and also in patients who were biochemically cured than in those who were not (P = 0.02). In the whole series of patients and controls, calcitonin (CT) and serum miR-375 levels were correlated at diagnosis (R2 = 0.40, P < 0.01), but in a U-shaped manner: a positive correlation was found with low CT levels, then the correlation turns negative as CT rises (in MTC patients). A negative correlation was indeed found in MTC patients between serum miR-375 and CT (R2 = -0.10, P = 0.01). On ROC curve analysis, a cut-off of 2.1 for serum miR-375 proved capable of distinguishing between MTC patients and the other patients and controls with a 92.6% sensitivity and a 97.6% specificity (AUC: 0.978, P < 0.01). Conclusions: Serum miR-375 levels can serve as a marker in the diagnosis of MTC, with a remarkable specificity. Serum miR-375 also proved a novel marker of prognosis in this disease. Further in vitro experiments to corroborate our results are currently underway.

Changing Dietary Habits in Veneto Region over Two Decades: Still a Long Road to Go to Reach an Iodine-Sufficient Status.

Background: Fifteen years after a nationwide voluntary iodine prophylaxis program was introduced, the aims of the present study were: (a) to obtain an up-to-date assessment of dietary iodine intake in the Veneto region, Italy; and (b) to assess dietary and socioeconomic factors that might influence iodine status. Methods: Urinary iodine concentration (UIC) was obtained in 747 school students (median age 13 years; range: 11-16 years). Results: The median UIC was 111 µg/L, with 56% of samples ≥ 100 µg/L, but 26% were < 50 µg/L, more frequently females. Iodized salt was used by 82% of the students. The median UIC was higher among users of iodized salt than among non-users, 117.0 ug/L versus 90 ug/L (p = 0.01). The median UIC was higher in regular consumers of cow's milk than in occasional consumers, 132.0 µg/L versus 96.0 µg/L (p < 0.01). A regular intake of milk and/or the use of iodized salt sufficed to reach an adequate median UIC, although satisfying only with the combined use. A trend towards higher UIC values emerged in regular consumers of cheese and yogurt. Conclusion: Iodine status has improved (median UIC 111.0 µg/L), but it is still not adequate as 26% had a UIC < 50 µg/L in the resident population of the Veneto region. A more widespread use of iodized salt but also milk and milk product consumption may have been one of the key factors in achieving this partial improvement.