Thyrotropin regulates thyroid cell proliferation by up-regulating miR-23b and miR-29b that target SMAD3

Recombinant Human TSH Fails to Induce the Proliferation and Migration of Papillary Thyroid Carcinoma Cell Lines

Thyrotropin (TSH) suppression is required in the management of patients with papillary thyroid carcinoma (PTC) to improve their outcomes, inevitably causing iatrogenic thyrotoxicosis. Nevertheless, the evidence supporting this practice remains limited and weak, and in vitro studies examining the mitogenic effects of TSH in cancerous cells used supraphysiological doses of bovine TSH, which produced conflicting results. Our study explores, for the first time, the impact of human recombinant thyrotropin (rh-TSH) on human PTC cell lines (K1 and TPC-1) that were transformed to overexpress the thyrotropin receptor (TSHR). The cells were treated with escalating doses of rh-TSH under various conditions, such as the presence or absence of insulin. The expression levels of TSHR and thyroglobulin (Tg) were determined, and subsequently, the proliferation and migration of both transformed and non-transformed cells were assessed. Under the conditions employed, rh-TSH was not adequate to induce either the proliferation or the migration rate of the cells, while Tg expression was increased. Our experiments indicate that clinically relevant concentrations of rh-TSH cannot induce proliferation and migration in PTC cell lines, even after the overexpression of TSHR. Further research is warranted to dissect the underlying molecular mechanisms, and these results could translate into better management of treatment for PTC patients.

TGFβ signaling pathways in human health and disease

Transforming growth factor beta (TGFβ) is named for the function it was originally discovered to perform-transformation of normal cells into aggressively growing malignant cells. It became apparent after more than 30 years of research, however, that TGFβ is a multifaceted molecule with a myriad of different activities. TGFβs are widely expressed with almost every cell in the human body producing one or another TGFβ family member and expressing its receptors. Importantly, specific effects of this growth factor family differ in different cell types and under different physiologic and pathologic conditions. One of the more important and critical TGFβ activities is the regulation of cell fate, especially in the vasculature, that will be the focus of this review.

Genomic and epigenomic profile of thyroid cancer

Thyroid cancer is the most common malignancy of the endocrine system, and its incidence has been steadily increasing. Advances in sequencing have allowed analysis of the entire cancer genome, and has provided new information on the genetic lesions and modifications responsible for the onset, progression, dedifferentiation and metastasis of thyroid carcinomas. Moreover, integrated genomics has advanced our understanding of the development of cancer and its behavior, and has facilitated the identification of new genetic mutations and molecular pathways. The functional analysis of epigenetic modifications, such as DNA methylation, histone acetylation and non-coding RNAs, have contributed to define new regulatory mechanisms that control cell malignancy in thyroid cancer, especially aggressive forms. Here we review the most recent advances in genomics and epigenomics of thyroid cancer, which have resulted in a new classification and interpretation of the initiation and progression of thyroid tumors, providing new tools and opportunities for further investigation and for the clinical development of new treatment strategies.

MiR-29b expression is altered in crescent formation of HSPN and accelerates Ang II-induced mesangial cell activation

BACKGROUND

MicroRNA-29b (miR-29b) has been suggested to possess pro-inflammatory activity, which can partially be explained by the repression of tumor necrosis factor alpha protein three antibody (TNFAIP3). Meanwhile, it also promotes thyroid cell proliferation via Smad signaling pathways. The present study aimed to elucidate the role of miR-29b in Henoch Schönlein purpura nephritis (HSPN) and its underlying molecular mechanism in angiotensin II (Ang II)-induced human glomerular mesangial cell (HGMC) activation.

METHODS

We evaluated miR-29b expression in 35 HSPN renal tissues based on crescent formation, glomerular sclerosis, interstitial fibrosis, thrombosis formation and capillary loop necrosis. Meanwhile, HGMCs were cultured, treated with Ang II and then transfected with LV-hsa-miR-29b-1 to induce miR-29b overexpression or LV-hsa-miR-29b-3p-inhibition to inhibit miR-29b expression. Finally, we examined the effects of miR-29b on cell proliferation and release of inflammatory mediators.

RESULTS

We observed that miR-29b expression was significantly higher in the crescent group than in the no crescent group. MiR-29b overexpression induced the release of intercellular adhesion molecule-1, interleukin-1β (IL-1β), IL-6, IL-8, the increase of CyclinA2, CyclinD1, and cell proliferation. It also could inhibit the expressions of TNFAIP3 and NF-kappa-B-repressing factor (NKRF). Correspondingly, miR-29b inhibition produced the opposite effects and increased the expression of TNFAIP3 and NKRF.

CONCLUSION

MiR-29b expression is altered in crescent formation of HSPN and accelerates Ang II-induced mesangial cell proliferation and release of inflammatory mediators.

The Effect of Inflammation on the Formation of Thyroid Nodules

BACKGROUND

Some studies have demonstrated that inflammation is highly associated with the prevalence of thyroid nodules (TNs). However, more confounders, such as metabolic diseases, should be adjusted.

METHODS

A clinical study collecting 2722 subjects was conducted to confirm the association between inflammation and TNs. The underlying mechanism was investigated in combination with bioinformatics analysis.

RESULTS

In the clinical study, propensity score matching was used to match metabolic parameters and other confounders, and it is observed that subjects with high inflammation had a higher prevalence of TNs and thyroid-stimulating hormone (TSH) than those with low inflammation. After further matching TNs, it is found that inflammation was positively associated with TSH, which was also demonstrated in a population without TNs. In bioinformatics study, inflammation did not promote TNs formation directly. Instead, it inhibited the synthesis of thyroid hormone, which might be the cause of the elevated TSH coexisting with inflammation.

CONCLUSION

Inflammation promotes the development of TNs disease, probably due to its indirect effect through inhibiting the synthesis of thyroid hormone, which results in the elevation of TSH.

10‑Hydroxycamptothecin induces apoptosis in human fibroblasts by regulating miRNA‑23b‑3p expression

10-Hydroxycamptothecin (HCPT) effectively controls epidural fibrosis, but the exact underlying mechanisms remain ambiguous. Abnormal microRNA (miR)-23b-3p expression has been detected in various types of fibrotic tissues that are present in different diseases. The aim of the present study was to elucidate the mechanisms through which HCPT induces fibroblast apoptosis. Reverse transcription-quantitative polymerase chain reactions were performed on six traumatic scar samples and matched normal skin samples; traumatic scar formation was revealed to be significantly inversely associated with miR-23b-3p expression. In addition, the miR-23b-3p expression level in human fibroblasts was examined following HCPT treatment. The effects of HCPT and miR-23b-3p on fibroblast apoptosis were assessed using terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling, flow cytometry and western blot analysis. The results demonstrated that HCPT treatment notably increased miR-23b-3p expression levels and accelerated fibroblast apoptosis. Therefore, upregulation of miR-23b-3p expression was demonstrated to promote fibroblast apoptosis, consistently with the effects of HCPT. The results of the present study indicated that HCPT may induce fibroblast apoptosis by regulating miR-23b-3p expression.

A Mechanism Exploration of Metabolic Syndrome Causing Nodular Thyroid Disease

BACKGROUND

Metabolic syndrome (MS) and its components have been demonstrated to facilitate the prevalence of thyroid nodules (TNs). The underlying pathogenesis needs to be elucidated.

METHODS

A total of 2722 subjects, who underwent health checkup in our institute from December 2014 to November 2018, were retrospectively and randomly collected. After exclusion, 2068 subjects were chosen, and their anthropic and clinical data were collected.

RESULTS

After matching age, gender, uric acid (UA), and creatinine (Cr) by propensity score matching (PSM), subjects with MS had higher prevalence of TNs than those without MS, as well as higher thyroid-stimulating hormone (TSH) and inflammatory levels, indicated by the higher white blood cell (WBC), lymphocyte (LY), and monocyte/high-density lipoprotein (Mo/HDL). After matching age, gender, UA, Cr, TSH, free triiodothyronine (FT3), thyroxine (FT4), WBC, NE, LY, Mo, NE/LY, LY/Mo, and Mo/HDL by PSM, no significant difference of the prevalence of TNs was found between MS and non-MS groups. Step logistic regression suggested glucose intolerance (GI), among all the components of MS, was an independent impact factor of TNs and was considered to contribute most to the formation of TNs. The prevalence of TNs was higher in the GI group after matching age, gender, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood sugar (FBS), UA, Cr, triglyceride (TG), cholesterol (CHOL), HDL, and low-density lipoprotein (LDL).

CONCLUSIONS

Patients with MS have a higher prevalence of TNs, probably due to the elevated TSH and inflammatory levels in vivo. Among the components of MS, glucose intolerance contributes most to the development of TNs.

miRNA-Directed Regulation of the Main Signaling Pathways in Thyroid Cancer

In the last two decades, great strides have been made in the study of microRNAs in development and in diseases such as cancer, as reflected in the exponential increase in the number of reviews on this topic including those on undifferentiated and well-differentiated thyroid cancer. Nevertheless, few reviews have focused on understanding the functional significance of the most up- or down-regulated miRNAs in thyroid cancer for the main signaling pathways hyperactivated in this tumor type. The aim of this review is to discuss the major miRNAs targeting proteins of the MAPK, PI3K, and TGFβ pathways, to define their mechanisms of action through the 3'UTR regions of their target genes, and to describe how they affect thyroid tumorigenesis through their actions on cell proliferation, migration, and invasion. Given the importance of miRNAs in cancer as diagnostic, prognostic and therapeutic candidates, a better understanding of this cross-talk might shed new light on the biomedical treatment of thyroid cancer.

MicroRNAs in thyroid development, function and tumorigenesis

MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression that modulate the vast majority of cellular processes. During development, the correct timing and expression of miRNAs in the tissue differentiation is essential for organogenesis and functionality. In thyroid gland, DICER and miRNAs are necessary for accurately establishing thyroid follicles and hormone synthesis. Moreover, DICER1 mutations and miRNA deregulation observed in human goiter influence thyroid tumorigenesis. The thyroid malignant transformation by MAPK oncogenes is accompanied by global miRNA changes, with a marked reduction of "tumor-suppressor" miRNAs and activation of oncogenic miRNAs. Loss of thyroid cell differentiation/function, and consequently iodine trapping impairment, is an important clinical characteristic of radioiodine-refractory thyroid cancer. However, few studies have addressed the direct role of miRNAs in thyroid gland physiology. Here, we focus on what we have learned in the thyroid follicular cell differentiation and function as revealed by cell and animal models and miRNA modulation in thyroid tumorigenesis.

Regulation and biological roles of the multifaceted miRNA-23b (MIR23B)

MicroRNAs (miRNAs) are important short endogenous non-coding RNAs that have critical biological roles by acting as post-transcriptional regulators of gene expression. Chromosomal region 9q22.32 encodes the miR-23b/27b/24-1 cluster and produces miR-23b, which is a pleiotropic modulator in many developmental processes and pathological conditions. Expression of miR-23b is actively suppressed and induced in response to many different stimuli. We discuss the biological functions and transcriptional regulation of this multifaceted miRNA in different tumor types, during development, upon viral infection, as well as in various clinical disorders, immune responses, as well as cardiovascular and thyroid functions. The combined body of work suggests that miR-23b expression is modulated by a diverse array of stimuli in cells from different lineages and participates in multiple gene regulatory feedback loops. Elevation of miR-23b levels appears to instruct cells to limit their proliferative and migratory potential, while promoting the acquisition of specialized phenotypes or protection from invading viruses and parasites. In contrast, loss of miR-23b can deregulate normal tissue homeostasis by removing constraints on cell cycle progression and cell motility. Collectively, the findings on miR-23b indicate that it is a very potent post-transcriptional regulator of growth and differentiation during development, multiple cancers and other biological processes. Understanding the regulation and activity of miR-23b has significant diagnostic value in many biological disorders and may identify cellular pathways that are amenable to therapeutic intervention.

Mir-29b Mediates the Neural Tube versus Neural Crest Fate Decision during Embryonic Stem Cell Neural Differentiation

During gastrulation, the neuroectoderm cells form the neural tube and neural crest. The nervous system contains significantly more microRNAs than other tissues, but the role of microRNAs in controlling the differentiation of neuroectodermal cells into neural tube epithelial (NTE) cells and neural crest cells (NCCs) remains unknown. Using embryonic stem cell (ESC) neural differentiation systems, we found that miR-29b was upregulated in NTE cells and downregulated in NCCs. MiR-29b promoted the differentiation of ESCs into NTE cells and inhibited their differentiation into NCCs. Accordingly, the inhibition of miR-29b significantly inhibited the differentiation of NTE cells. A mechanistic study revealed that miR-29b targets DNA methyltransferase 3a (Dnmt3a) to regulate neural differentiation. Moreover, miR-29b mediated the function of Pou3f1, a critical neural transcription factor. Therefore, our study showed that the Pou3f1-miR-29b-Dnmt3a regulatory axis was active at the initial stage of neural differentiation and regulated the determination of cell fate.

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MiR-29b promoted NTE differentiation and inhibited NCC differentiation from ESCs

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MiR-29b targeted Dnmt3a to regulate neural differentiation

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MiR-29b mediated the function of Pou3f1

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The Pou3f1-miR-29b-Dnmt3a axis regulated the cell fate determination

Suppressive effect of microRNA-29b on hepatic stellate cell activation and its crosstalk with TGF-β1/Smad3

The microRNA (miR)‐29 family is closely associated with fibrotic processes by virtue of its low expression in many tissues during organ fibrosis. The present study investigated whether miR‐29b overexpression suppressed hepatic stellate cell (HSC) activation and its interactions with transforming growth factor (TGF)‐β1/mothers against decapentaplegic homolog 3 (Smad3), a classical signal transduction pathway contributing to the activation of HSCs. The results showed that transfection of LX‐2 (human HSC) cells with miR‐29b mimic or pSUPER‐Smad3 silencing (si)RNA resulted in significantly increased expression of miR‐29b and decreased expression of Smad3. miR‐29b overexpression inhibited proliferation of LX‐2 cells 24 h after transfection. Both miR‐29b overexpression and Smad3 silencing antagonized the effects of TGF‐β1 on the expression of α‐smooth muscle actin (α‐SMA) and collagen type I (col‐1). Furthermore, infection with miR‐29b mimics suppressed Smad3 and TGF‐β1 expression, suggesting that miR‐29b inhibited LX‐2 activation mediated by both Smad3 and TGF‐β1. Nevertheless, primary miR‐29a/b1, miR‐29b2/c and mature miR‐29b were downregulated by TGF‐β1 and stimulated by Smad3 silencing, suggesting that TGF‐β1/Smad3 signalling pathway regulate not just mature miR‐29b but also its transcription. In summary, our results show overwhelming evidence corroborating the suppressive effect of miR‐29b on TGF‐β1‐induced LX‐2 cell activation. The results also revealed the existence of crosstalk between miR‐29b and TGF‐β1/Smad3 during LX‐2 activation, suggesting a feedback loop between miR‐29b and TGF‐β1/Smad3 signalling that promotes liver fibrosis. Copyright © 2016 The Authors. Cell Biochemistry and Function published by John Wiley & Sons, Ltd.

PATZ1 is a target of miR-29b that is induced by Ha-Ras oncogene in rat thyroid cells

The regulatory transcriptional factor PATZ1 is constantly downregulated in human thyroid cancer where it acts as a tumour suppressor by targeting p53-dependent genes involved in Epithelial-Mesenchymal Transition and cell migration. The aim of the present work was to elucidate the upstream signalling mechanisms regulating PATZ1 expression in thyroid cancer cells. The bioinformatics search for microRNAs able to potentially target PATZ1 led to the identification of several miRNAs. Among them we focused on the miR-29b since it was found upregulated in rat thyroid differentiated cells transformed by the Ha-Ras oncogene towards a high proliferating and high migratory phenotype resembling that of anaplastic carcinomas. Functional assays confirmed PATZ1 as a target of miR-29b, and, consistently, an inverse correlation between miR-29b and PATZ1 protein levels was found upon induction of Ha-Ras oncogene expression in these cells. Interestingly, restoration of PATZ1 expression in rat thyroid cells stably expressing the Ha-Ras oncogene decreased cell proliferation and migration, indicating a key role of PATZ1 in Ras-driven thyroid transformation. Together, these results suggest a novel mechanism regulating PATZ1 expression based on the upregulation of miR-29b expression induced by Ras oncogene.

Effects and mechanism of miR-23b on glucose-mediated epithelial-to-mesenchymal transition in diabetic nephropathy

MicroRNAs (miRNAs) play important roles in epithelial-to-mesenchymal transition (EMT). Moreover, hyperglycaemia induces damage to renal tubular epithelial cells, which may lead to EMT in diabetic nephropathy. However, the effects of miRNAs on EMT in diabetic nephropathy are poorly understood. In the present study, we found that the level of microRNA-23b (miR-23b) was significantly decreased in high glucose (HG)-induced human kidney proximal tubular epithelial cells (HK2) and in kidney tissues of db/db mice. Overexpression of miR-23b attenuated HG-induced EMT, whereas knockdown of miR-23b induced normal glucose (NG)-mediated EMT in HK2 cells. Mechanistically, miR-23b suppressed EMT in diabetic nephropathy by targeting high mobility group A2 (HMGA2), thereby repressing PI3K-AKT signalling pathway activation. Additionally, HMGA2 knockdown or inhibition of the PI3K-AKT signalling pathway with LY294002 mimicked the effects of miR-23b overexpression on HG-mediated EMT, whereas HMGA2 overexpression or activation of the PI3K-AKT signalling pathway with BpV prevented the effects of miR-23b on HG-mediated EMT. We also confirmed that overexpression of miR-23b alleviated EMT, decreased the expression levels of EMT-related genes, ameliorated renal morphology, glycogen accumulation, fibrotic responses and improved renal functions in db/db mice. Taken together, we showed for the first time that miR-23b acts as a suppressor of EMT in diabetic nephropathy through repressing PI3K-AKT signalling pathway activation by targeting HMGA2, which maybe a potential therapeutic target for diabetes-induced renal dysfunction.

miR-130b-3p Upregulation Contributes to the Development of Thyroid Adenomas Targeting CCDC6 Gene

We have previously studied the function of microRNAs (miRNAs) in thyroid cells using the differentiated rat thyroid PC Cl 3 cells that need thyrotropin (TSH) for their growth. The miRNA expression profile examination allowed the detection of a set of miRNAs downregulated and upregulated by TSH. Here, we first demonstrated that upregulation of miR-130b-3p occurs through a protein kinase A-cAMP-responsive element binding protein (CREB)-dependent mechanism. Then, we analyzed its expression in human thyroid follicular adenomas, where a constitutive CREB activation is frequently present. miR-130b-3p results in upregulation with a high fold-change in most thyroid follicular adenomas. Then, we identified CCDC6, coding for a protein that interacts with CREB1 leading to the transcriptional repression of CREB1 target genes, as a target of this miRNA. The targeting of CCDC6 by miR-130b-3p likely accounts for the mechanism by which its upregulation contributes to the development of thyroid adenomas increasing CREB1 activity.

microRNA-29b: an emerging player in human cancer

MicroRNAs (miRNAs) are ubiquitously expressed small, non-coding RNAs that negatively regulate gene expression at a post transcriptional/translational level. They have emerging as playing crucial roles in cancer at all stages ranging from initiation to metastasis. As a tumor suppressor miRNA, aberrant expression of microRNA-29b (miR-29b) has been detected in various types of cancer, and its disturbance is related with tumor development and progression. In this review, we summarize the latest findings with regard to the tumor suppressor signature of miR-29b and its regulatory mechanisms. Our review highlights the diverse relationships between miR-29b and its target genes in malignant tumors.

MicroRNA-23b Inhibits the Proliferation and Migration of Heat-Denatured Fibroblasts by Targeting Smad3

Background

Skin grafting with the preservation of denatured dermis is a novel strategy for the treatment of burn-injured skin. Denatured dermis has the ability to restore to the morphology and function of normal skin, but the underlying molecular mechanism is elusive. MicroRNAs (miRNA) are small noncoding RNAs and regulate normal physiology as well as disease development. In this study, we assessed the potential role of miRNA-23b (miR-23b) in the regulation of cell proliferation and migration of heat-denatured fibroblasts and identified the underlying mechanism.

Methods

The expression of miR-23b in denatured dermis and heat-denatured fibroblasts was detected by quantitative real-time polymerase chain reaction (RT-PCR). The effects of miR-23b on cell proliferation and migration of heat-denatured fibroblasts were assessed by transient transfection of miR-23b mimics and inhibitor. The target gene of miR-23b and the downstream pathway were further investigated.

Results

miR-23b was downregulated in denatured dermis and heat-denatured fibroblasts. Downregulation of miR-23b dramatically promoted the proliferation and migration of heat-denatured fibroblasts. Subsequent analyses demonstrated that Smad3 was a direct and functional target of miR-23b in heat-denatured fibroblasts, which was validated by the dual luciferase reporter assay. Moreover, immunohistochemistry analysis showed that denatured dermis from rats displayed enhanced staining of Smad3. In addition, miR-23b modulated denatured dermis by activating the Notch1 and TGF-β signaling pathways.

Conclusions

Our findings suggest that downregulation of miR-23b contributes to the recovery of denatured dermis, which may be valuable for treatment of skin burns.

MiRNA expression may account for chronic but not for acute regulation of mRNA expression in human thyroid tumor models

Background

For thyroid tumorigenesis, two main human in vitro models are available: primary cultures of human thyrocytes treated with TSH or EGF/serum as models for autonomous adenomas (AA) or papillary thyroid carcinomas (PTC) respectively, and human thyroid tumor derived cell lines. Previous works of our group have assessed properties of those models, with a special emphasis on mRNA regulations. It is often assumed that miRNA may be one of the primary events inducing these mRNA regulations.

Methods

The purpose of this study was to investigate the representativity of those models to study microRNA regulations and their relation with mRNA expression. To achieve this aim, the miRNA expressions profiles of primary cultures treated with TSH or EGF/serum and of 6 thyroid cancer cell lines were compared to the expression profiles of 35 tumor tissues obtained by microarrays.

Results

Our data on primary cultures have shown that the TSH or EGF/serum treatment did not greatly modify the microRNA expression profiles, which is contrary to what is observed for mRNA expression profiles, although they still evolved differently according to the treatment. The analysis of miRNA and mRNA expressions profiles in the cell lines has shown that they have evolved into a common, dedifferentiated phenotype, closer to ATC than to the tumors they are derived from.

Conclusions

Long-terms TSH or EGF/serum treatments do not mimic AA or PTC respectively in terms of miRNA expression as they do for mRNA, suggesting that the regulations of mRNA expression induced by these physiological agents occur independently of miRNA. The general patterns of miRNA expression in the cell lines suggest that they represent a useful model for undifferentiated thyroid cancer. Mirna probably do not mediate the rapid changes in gene expression in rapid cell biology regulation.

The miRNA23b-regulated signaling network as a key to cancer development--implications for translational research and therapeutics

A growing body of evidence indicates that microRNA23b (miR23b) is pleiotropic-it plays important roles in regulating physiological functions of cells, in regulating differentiation of cells and in regulating cellular immune responses. Our review of the literature showed that dysregulation of miR23b expression is implicated in the disruption of these cellular mechanisms and development of diseases such as cancer. MiR23b dysregulation appears to do this by modulating the expression level of candidate gene products involved in a network of signaling pathways including TGF-beta and Notch pathways that govern malignant properties of cancer cells such as motility and invasiveness. More recently, miR23b regulation of gene expression has also been associated with cancer stem cells and chemoresistance. Our review covers miR23b's role in immunity, endothelial function, differentiation, and cancer as well as its potential for translation into future cancer diagnostics and therapeutics.

Mir-23b and miR-130b expression is downregulated in pituitary adenomas

MicroRNA (miRNA) deregulation plays a critical role in tumorigenesis. miR-23b and miR-130b are induced by thyrotropin in thyroid cells in a cAMP-dependent manner. The aim of our work has been to investigate the possible role of miR-23b and miR-130b in pituitary tumorigenesis. We have analyzed their expression in a panel of pituitary adenomas (PAs) including GH and NFPA adenomas. We report that miR-23b and miR-130b are drastically reduced in GH, gonadotroph and NFPA adenomas in comparison with normal pituitary gland. Interestingly, the overexpression of miR-23b and miR-130b inhibits cell proliferation arresting the cells in the G1 and G2 phase of the cell cycle, respectively. Moreover, we demonstrate that miR-23b and miR-130b target HMGA2 and cyclin A2 (CCNA2) genes, respectively. Finally, downregulation of miR-23b and miR-130b expression is associated with increased levels of their respective targets in human PAs. These findings suggest that miR-23b and miR-130b downregulation may contribute to pituitary tumorigenesis.

MicroRNA profile of poorly differentiated thyroid carcinomas: new diagnostic and prognostic insights

The diagnosis of conventional and oncocytic poorly differentiated (oPD) thyroid carcinomas is difficult. The aim of this study is to characterise their largely unknown miRNA expression profile and to compare it with well-differentiated thyroid tumours, as well as to identify miRNAs which could potentially serve as diagnostic and prognostic markers. A total of 14 poorly differentiated (PD), 13 oPD, 72 well-differentiated thyroid carcinomas and eight normal thyroid specimens were studied for the expression of 768 miRNAs using PCR-Microarrays. MiRNA expression was different between PD and oPD thyroid carcinomas, demonstrating individual clusters on the clustering analysis. Both tumour types showed upregulation of miR-125a-5p, -15a-3p, -182, -183-3p, -222, -222-5p, and downregulation of miR-130b, -139-5p, -150, -193a-5p, -219-5p, -23b, -451, -455-3p and of miR-886-3p as compared with normal thyroid tissue. In addition, the oPD thyroid carcinomas demonstrated upregulation of miR-221 and miR-885-5p. The difference in expression was also observed between miRNA expression in PD and well-differentiated tumours. The CHAID algorithm allowed the separation of PD from well-differentiated thyroid carcinomas with 73-79% accuracy using miR-23b and miR-150 as a separator. Kaplan-Meier and multivariate analysis showed a significant association with tumour relapses (for miR-23b) and with tumour-specific death (for miR-150) in PD and oPD thyroid carcinomas. MiRNA expression is different in conventional and oPD thyroid carcinomas in comparison with well-differentiated thyroid cancers and can be used for discrimination between these tumour types. The newly identified deregulated miRNAs (miR-150, miR-23b) bear the potential to be used in a clinical setting, delivering prognostic and diagnostic informations.

The miR-92b functions as a potential oncogene by targeting on Smad3 in glioblastomas

MicroRNAs(miR) play an important role in cell growth, differentiation, proliferation and apoptosis, which can function either as oncogenes or as tumor suppressors in their effect on tumor growth. Smad3 is often underexpressed in very diverse types of malignant tumors and has an important tumor suppressive function; however, the underlying mechanism in solid cancer including glioblastomas(GBM) is not fully explored. The aim of this study is to explore the role of miR-92b in regulation of smad3 in GBM. In our study, we found that miR-92b expression was significantly increased in GBM tissues compared with normal brain tissues by Q-RT-PCR and in situ hybridization (P<0.01). However, expression of smad3 in GBM samples was significantly reduced compared with normal brain tissues by western blot and immunohistochemistry (P<0.05). Using 3'UTR luciferase reporter gene assay, we found that miR-92b directly affected smad3 expression in GBM cells by targeting the 3'-untranslated region. Silencing of miR-92b was able to significantly inhibit the viability of GBM cells in three GBM cell lines through up-regulating the TGF-beta/smad3/p21 signaling pathway in vitro. Furthermore, the tumor growth and the weight of U87 cells in the miR-92b inhibitor group were significantly inhibited when compared with that of the control group in vivo. Our data demonstrated that miR-92b may be considered as a tumor oncogene to promote GBM cell proliferation, and thus may serve as a potentially useful target for development of miRNA-based therapies in the future.

Impact of alcohol use on thyroid function

Alcohol is one of the commonest illicit psychoactive substances consumed globally and is the world's third largest risk factor for disease and disability. It has been reported to have multiple effects on the hypothalamo-pituitary-thyroid axis and the functioning of the thyroid gland. It has been reported to cause direct suppression of thyroid function by cellular toxicity, and indirect suppression by blunting thyrotropin-releasing hormone response. It causes a decrease of peripheral thyroid hormones during chronic use and in withdrawal. Alcohol use may also confer some protective effect against thyroid nodularity, goiter, and thyroid cancer. This article presents a review of the clinically relevant effects of alcohol on the functioning of the thyroid gland and also discusses the effect of medication used in treatment of alcohol dependence on thyroid function.

Efficient tumorigenesis by mutation-induced failure to terminate microRNA-mediated adaptive hyperplasia

Seven current contending cancer theories consider different sets of critical events as sufficient for tumorigenesis. These theories, most recently the microRNA dysregulation (MRD) theory, have overlapping attributes and extensive empirical support, but also some discrepancies, and some do not address both benign and malignant tumorigenesis. By definition, the most efficient tumorigenic pathways will dominate under conditions that selectively activate those pathways. The MRD theory provides a mechanistic basis to combine elements of the current theories into a new hypothesis that: (i) tumors arise most efficiently under stress that induces and sustains either protective or regenerative states of adaptive hyperplasia (AH) that normally are epigenetically maintained unless terminated; and (ii) if dysregulated by a somatic mutation that prevents normal termination, these two AH states can generate benign and malignant tumors, respectively. This hypothesis, but not multistage cancer theory, predicts that key participating AH-stem-cell populations expand markedly when triggered by stress, particularly chronic metabolic or oxidative stress, mechanical irritation, toxic exposure, wounding, inflammation, and/or infection. This hypothesis predicts that microRNA expression patterns in benign vs. malignant tumor tissue will correlate best with those governing protective vs. regenerative AH in that tissue, and that tumors arise most efficiently inmutagen-exposed stem cells that either happen to be in, or incidentally later become recruited into, an AH state.