Human Normal Thyroid Tissue Research Articles

Papillary Thyroid Carcinoma and Cushing’s Disease: A Rare Association With Multiple Endocrine Neoplasia Type 1

Introduction: Multiple Endocrine Neoplasia type 1 (MEN1) is characterized by tumours of the parathyroid glands, neuroendocrine pancreatic tumour (PNET), and anterior pituitary. Studies suggest that MEN1 gen is not etiologically related to the oncogenesis of the papillary thyroid carcinoma (PTC). Expression of menin is preserved in human normal thyroid tissue and THc. Papillary thyroid carcinoma (PTC) combined with multiple endocrine neoplasia type 1 is a rare association. Cushing Syndrome (CS) is another rare associated condition with MEN-1. In patients with MEN1, CS can result from pituitary, adrenal, or other endocrine tumours. In large series of MEN-1 CS has low frequency (0.5%) or not described. Clinical Case: A.M.F.A, 49 years, female. In 2007, cytological study of thyroid nodules resulted in PTC, underwent total thyroidectomy. Anatomopathological (AP) confirmed PTC. She was followed with an excellent response to therapy. In 2018, abdominal ultrasound due to epigastric pain showed pancreatic lesion. MRI confirmed lesion in the head and body of the pancreas of 8.2cm. She underwent total gastroduodenopacreatectomy (TGDP), AP showed a well-differentiated PNET (KI67: 2%). Before TGDP, tests for MEN-1 were collected: IGF-1 of 450 ng/ml (RV for age: 90-249 ng/ml); calcium: 1,46 nmol/l (RV: 1,12-1,40), PTH: 91,7 pg/ml (RV: 15-65), prolactin 13,3 ng/ml (RV: 5-23), gastrin 22pg/ml (RV 13-115), and late night salivary cortisol (LNSC): 8,3 nmol/l (RV <7,6). Pituitary MRI showed a 0.5cm intrasellar nodule. Genetic study revealed c654 + 1G>T mutation in heterozygosity. O3 family members had the same mutation. To investigate hypercortisolism, it was made basal ACTH (56,1 pg/ml (VR 46 pg/ml), urine free cortisol (UFC) of 261,0 mcg/24h, 1mg DST of 15,2 mcg/dl (RV <1,8), basal cortisol of 16,5 mcg/dl and 8mg DST of 13,7 mcg/dl (not 50% suppressing of basal value). Another measurement of IGF-1 (after the PNET surgery) was normal. A petrosal venous sinus catheterization (PVSC) was made, which was compatible with Cushing’s disease (CD). She had brittle hair, facial plethora, proximal muscle weakness and easily bruising, without other clinical CS aspects. Treatment with ketoconazole was initiated and she was referred to transesphenoidal surgery. Conclusion: Patient had two rare presentation of MEN1, first manifestation was PTC. PNET and CD was diagnosed 11 years late during clinical follow up. In this patient, MEN1 syndrome may have predisposed the patient to developing PTC. Currently, little is known about the prevalence of THc in MEN1 and it is unclear whether tumorigenesis is related. Further studies and additional case reports are required to clarify this connection. Also, we observed IGF-1 value normalized after TGDP, so it could be caused by a functional PNET. Rare causes of acromegaly are excess secretion of GH-releasing hormone (GHRH) by hypothalamic tumours, and ectopic GHRH or GH secretion by NET.

MiR-150 Inhibits Cell Growth In Vitro and In Vivo by Restraining the RAB11A/WNT/β-Catenin Pathway in Thyroid Cancer.

BackgroundEmerging evidence has shown that downregulation or upregulation of microRNAs (miRNAs) plays an important role in the development and progression of thyroid cancer (TC). However, the potential role of miR-150 and its biological function in TC remains largely unclear.Material/MethodsReal-time polymerase chain reaction (RT-qPCR) was employed to detect the expression level of miR-150 and RAB11A in human TC tissue and human normal thyroid tissue. MTT assay, colony formation assay, flow cytometry cell cycle, and apoptosis assay were used to investigate the role of miR-150 and RAB11A on the malignant phenotypes in vitro. Nude mouse xenograft assay and western blot assay was used to verify the function of miR-150 in vivo. Western blot assay and immunofluorescence assay were used to detect the activation of WNT/β-catenin pathway mediated by miR-150 and RAB11A. EGFP reporter assay, RT-qPCR assay, and western blot assay were used to validate the regulation relationship.ResultsThis study demonstrated that miR-150 expression in human TC tissues was markedly downregulated. Moreover, overexpression of miR-150 markedly inhibited cell proliferation via inducing the cell cycle arrest and promoting cell apoptosis by directly targeting RAB11A in vitro and suppressing tumor growth in vivo. However, overexpression of RAB11A promoted cell malignant phenotypes. In addition, miR-150 restrained the RAB11A mediated WNT/β-catenin activation in TC cells.ConclusionsmiR-150 may function as a suppressor gene in TC cells by inhibiting the RAB11A/WNT/β-catenin pathway.

Molecular Differences Between Human Thyroid Follicular Adenoma and Carcinoma Revealed by Analysis of a Murine Model of Thyroid Cancer

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.

Notch Signaling Is Involved in Expression of Thyrocyte Differentiation Markers and Is Down-Regulated in Thyroid Tumors

Notch genes encode receptors for a signaling pathway that regulates cell growth and differentiation in various contexts, but the role of Notch signaling in thyroid follicular cells has never been fully published. The objective of the study was to characterize the expression of Notch pathway components in thyroid follicular cells and Notch signaling activities in normal and transformed thyrocytes. DESIGN/SETTING AND PATIENTS: Expression of Notch pathway components and key markers of thyrocyte differentiation was analyzed in murine and human thyroid tissues (normal and tumoral) by quantitative RT-PCR and immunohistochemistry. The effects of Notch overexpression in human thyroid cancer cells and FTRL-5 cells were explored with analysis of gene expression, proliferation assays, and experiments involving transfection of a luciferase reporter construct containing human NIS promoter regions. Notch receptors are expressed during the development of murine thyrocytes, and their expression levels parallel those of thyroid differentiation markers. Notch signaling characterized also normal adult thyrocytes and is regulated by TSH. Notch pathway components are variably expressed in human normal thyroid tissue and thyroid tumors, but expression levels are clearly reduced in undifferentiated tumors. Overexpression of Notch-1 in thyroid cancer cells restores differentiation, reduces cell growth rates, and stimulates NIS expression via a direct action on the NIS promoter. Notch signaling is involved in the determination of thyroid cell fate and is a direct regulator of thyroid-specific gene expression. Its deregulation may contribute to the loss of differentiation associated with thyroid tumorigenesis.

Cloning and expression of human adenylyl cyclase type VI in normal thyroid tissues

The adenylyl cyclase type VI gene expressed in human normal thyroid tissue was cloned and sequenced. The cDNA sequence (6463 nt) is susceptible to code for a 1168 aa protein. Northern blots using specific probes showed that the expression of adenylyl cyclase type VI gene was significantly higher in one hyperfunctioning thyroid tumor than in normal thyroid tissue, in one follicular cold adenoma or in one papillary carcinoma.

Preferential induction of RET/PTC1 rearrangement by X-ray irradiation.

Ionizing radiation is a well known risk factor of thyroid cancer development, but the mechanism of radiation induced carcinogenesis is not clear. The RET/PTC oncogene, an activated form of the RET proto-oncogene, is frequently observed in papillary thyroid carcinoma (PTC); RET/PTC1, -2 and -3 are known to be the three major forms. High frequencies of RET/PTC rearrangements have been observed in radiation-associated PTC, such as those appearing post-Chernobyl or post-radiotherapy, but the rearrangement types differ between these two populations. We investigated whether a specific type of RET/PTC rearrangement was induced by X-rays in vivo and in vitro. In human normal thyroid tissues transplanted in scid mice, the RET/PTC1 rearrangement was predominantly detected throughout the observation period (up to 60 days) after X-ray exposure of 50 Gy. On the other hand, RET/PTC3 was detected only 7 days after X-irradiation, and no transcript of RET/PTC2 was detected. These results are supported by the results of an in vitro study. The RET/PTC1 rearrangement was preferentially induced in a dose-dependent manner by X-rays within a high dose range (10, 50 and 100 Gy) in four cell lines. On the other hand, RET/PTC3 was induced at a much lower frequency, and no induction of RET/PTC2 was observed. These results suggest that the preferential induction of the RET/PTC1 rearrangement may play an important role in the early steps of thyroid carcinogenesis induced by acute X-irradiation.

Effects of long-term, high-dose bovine thyrotropin administration on human thyroid tissues from patients with graves' disease and normal subjects xenografted into nude mice.

We have attempted to determine whether the administration of thyrotropin would have any different functional or histological effects on Graves' tissue as opposed to human normal thyroid tissue in an in vivo situation (i.e., after xenograft into nude athymic mice). A dosage of 0.03 units per mouse of bovine thyroid-stimulating hormone (b-TSH) was injected intraperitoneally daily for 6 consecutive weeks into xenografted mice. The parameters measured included the free T4 index and thyroid autoantibodies during the course of b-TSH injections. Tritiated (3H)-thymidine incorporation into thyroid epithelial cells (TECs) and TEC HLA-DR expression were measured in the thyroid tissue at the time of human surgery and at sacrifice; in addition, light-microscopical observations were made at those times. Although there was a decline in free T4 index values during the course of the study, there was light-microscopical evidence suggestive of hyperplasia in both types of xenografted thyroid tissue. The TSH appeared to result in thyrocyte down-regulation, possibly of receptor or postreceptor origin. The administration of the b-TSH seemed to induce TEC HLA-DR expression in this study. Because these results differ from the effects of TSH on TEC in vitro with respect to TEC HLA-DR expression, it may be postulated that there are other factors liberated in vivo in the nude mice that interact with the TEC and TSH and initiate the TEC HLA-DR expression. We conclude that there are no significant differences between the responses of Graves' tissue and the normal human thyroid tissue in these studies.

Measurement of thyroid cell surface antibodies by radioassay using human cultured thyroid cells.

The present report describes a sensitive and quantitative binding radioassay for measurement of thyroid cell surface antibodies (TCSAb). Enzyme-dispersed thyroid cells from surgical specimens of human normal thyroid tissue were used after 7 days of culture. 125I-labelled Graves' IgG was shown to bind to cultured thyroid cells. The binding was time-and temperature-dependent and increased linearly with the number of thyroid cells. Evidence for specificity was provided by the lack of binding of radioiodinated Graves' IgG to human fibroblasts and by the negligible binding of 125I-labelled normal IgG to thyroid cells. A dose-dependent inhibition of binding of 125I-labelled Graves' igG to thyroid cells was produced by the addition of graded amounts of the unlabelled original Graves' IgG preparation, but not by normal IgG. Assays for TCSAb were performed on IgG preparations from patients with and without thyroid autoimmune disorders using the original Graves' IgG preparation as reference standard. Results were expressed in terms of arbitrary units/100 microgram IgG, 1 unit corresponding to the minimum amount of the standard IgG producing a significant inhibition of binding. Negative tests were found in most normal subjects (15/18) while low TCSAb levels (less than or equal to 1.8 U/100 microgram IgG) were detected in 3 cases. Increased TCSAb levels were found in the majority of the patients wit Graves' disease (14/21), in most of the patients with idiopathic myxedema (9/10) and in all of those with Hashimoto's thyroiditis (10/10).