MicroRNA-based molecular classification of papillary thyroid carcinoma

The role of miR-222-2p in exosomes secreted by hexavalent chromium-induced premature senescent hepatocytes as a SASP component

With the development of world industrialization, the environmental pollution of hexavalent chromium [Cr(VI)] is becoming an increasingly serious problem. In particular, the mechanisms by which long-term and low-dose exposure to Cr(VI) leading the development of related cancers are not well understood. As senescent cells gradually lose their ability to proliferate and divide, they will not be malignantly transformed. However, Senescence-associated secretory phenotype (SASP) released by senescent cells into the cellular microenvironment can act on neighboring cells. Since SASP has a bidirectional regulatory role in the malignant transformation of cells. Hence, It is very necessary to identified the composition and function of SASP which secreted by Cr(VI) induced senescent L02 hepatocytes (S-L02). Exosomes, a vesicle-like substances released extracellularly after the fusion of intracellular multivesicular bodies with cell membrane, are important components of SASP and contain a large number of microRNAs (miRNAs). By establishing Cr(VI)-induced S-L02 model, we collected the exosomes from the supernatants of S-L02 and L02 culture medium respectively, and screened out the highly expressed miRNAs in the exosomes of S-L02, namely the new SASP components. Among them, the increase of miR-222-5p was the most significant. It was validated that as SASP, miR-222-5p can inhibit the proliferation of L02 and S-L02 hepatocytes and at the same time accelerate the proliferation and migration ability of HCC cells. Further mechanistic studies revealed that miR-222-5p attenuated the regulatory effect of protein phosphatase 2A subunit B isoform R2-α (PPP2R2A) on Akt via repressing its target gene PPP2R2A, causing reduced expressions of forkhead box O3 (FOXO3a), p27 and p21, and finally increasing the proliferation of HCC cells after diminishing the negative regulation of on cell cycle. This study certainly provides valuable laboratory evidence as well as potential therapeutic targets for the prevention and further personalized treatment of Cr(VI)-associated cancers.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Unraveling the Roles of miR-204-5p and HMGA2 in Papillary Thyroid Cancer Tumorigenesis

Thyroid cancer is the most common endocrine malignant tumor with an increasing incidence rate. Although differentiated types of thyroid cancer generally present good clinical outcomes, some dedifferentiate into aggressive and lethal forms. However, the molecular mechanisms governing aggressiveness and dedifferentiation are still poorly understood. Aberrant expression of miRNAs is often correlated to tumor development, and miR-204-5p has previously been identified in papillary thyroid carcinoma as downregulated and associated with aggressiveness. This study aimed to explore its role in thyroid tumorigenesis. To address this, gain-of-function experiments were performed by transiently transfecting miR-204-5p in thyroid cancer cell lines. Then, the clinical relevance of our data was evaluated in vivo. We prove that this miRNA inhibits cell invasion by regulating several targets associated with an epithelial-mesenchymal transition, such as SNAI2, TGFBR2, SOX4 and HMGA2. HMGA2 expression is regulated by the MAPK pathway but not by the PI3K, IGF1R or TGFβ pathways, and the inhibition of cell invasion by miR-204-5p involves direct binding and repression of HMGA2. Finally, we confirmed in vivo the relationship between miR-204-5p and HMGA2 in human PTC and a corresponding mouse model. Our data suggest that HMGA2 inhibition offers promising perspectives for thyroid cancer treatment.

Expression Levels of MicroRNA-300/BCL2L11 in Papillary Thyroid Cancer and Their Clinical Diagnostic Values

INTRODUCTION

This research aims to explore the expression levels of microRNA (miRNA)-300/BCL-2-like protein 11 (BCL2L11) and their values in the clinical diagnosis of papillary thyroid cancer (PTC).

METHODS

Pathological tissues that were surgically removed for thyroid disease were selected. miR-300 and BCL2L11 expression levels in the samples were measured. Receiver operating characteristic (ROC) curves were plotted to analyze miR-300 and BCL2L11 predictive values for PTC. Upon silencing miR-300 and silencing BCL2L11 in PTC cells, the corresponding miR-300 and BCL2L11 expression levels were tested, followed by examining PTC cell activities. The targeting relationship of miR-300 and BCL2L11 was detected by the bioinformatics website and luciferase activity assay.

RESULTS

miR-300 expression levels were elevated and BCL2L11 expression levels were reduced in PTC tissues. miR-300 and BCL2L11 expression levels in PTC tissues had a correlation with TNM stage and lymph node metastasis. The results of ROC curve revealed that both miR-300 and BCL2L11 had clinical predictive values for PTC. Mechanistically, miR-300 negatively regulated BCL2L11. The functional assays unveiled that silencing miR-300 impeded PTC cell activities, and silencing BCL2L11 induced PTC cell activities. In the rescue experiment, silencing BCL2L11 reversed the impacts of silencing miR-300 on PTC cell development.

CONCLUSION

This study underlines that miR-300 expression is increased and BCL2L11 expression is declined in PTC. miR-300 and BCL2L11 both have clinical predictive values for diagnosing PTC.

Clinical expression of microRNA-144-5p and its regulatory effect on renal function in uremia

OBJECTIVE

The study commits to probing the clinical expression of microRNA-144-5p (miR-144-5p) and its modulatory effect on the renal function of uremia.

METHODS

Levels of blood urea nitrogen (BUN), β2-microglobulin (β2-MG), serum creatinine (Scr), blood calcium (Ca), phosphorus (P), and intact parathyroid hormone (iPTH) and miR-144-5p expression in serum of uremia patients were detected. The correlation among miR-144-5p expression with BUN, β2-MG, Scr, Ca, P, and iPTH levels in uremic patients was analyzed. The rats were injected with miR-144-5p agomir to detect the change of BUN, Scr, β2-MG, Scr, Ca, P, and iPTH levels in uremic rats.

RESULTS

miR-144-5p expression in uremic patients was negatively correlated with BUN, Scr, β2-MG, P, and iPTH levels, and positively correlated with free Ca concentration in blood. miR-144-5p elevation reduced BUN, Scr, β2-MG, P, and iPTH levels, and increased free Ca concentration in blood in uremic rats.

CONCLUSION

miR-144-5p is lowly expressed, and miR-144-5p has a regulatory effect on renal function in uremia.

Significance of miRNAs on the thyroid cancer progression and resistance to treatment with special attention to the role of cross-talk between signaling pathways

Thyroid cancer (TC) is the most prevalent endocrine malignant tumor. It has many types, the Papillary thyroid cancer (PTC)(most common and follicular thyroid carcinoma (FTC). Several risk factors have been associated with TC radiation exposure, autoimmunity, and genetics. Microribonucleic acids (miRNAs) are the most important genetic determinants of TC. They are small chains of nucleic acids that are able to inhibit the expression of several target genes. They could target several genes involved in TC proliferation, angiogenesis, apoptosis, development, and even resistance to therapy. Besides, they could influence the stemness of TC. Moreover, they could regulate several signaling pathways such as WNT/β-catenin, PI3K/AKT/mTOR axis, JAK/STAT, TGF- β, EGFR, and P53. Besides signaling pathways, miRNAs are also involved in the resistance of TC to major treatments such as surgery, thyroid hormone-inhibiting therapy, radioactive iodine, and adjuvant radiation. The stability and sensitivity of several miRNAs might be exploited as an approach for the usage of miRNAs as diagnostic and/or prognostic tools in TC.

Contribution of microRNA-30d to the prevention of the thyroid cancer occurrence and progression: mechanism and implications

Thyroid cancer is a major endocrine tumor and represents an emerging health problem worldwide. MicroRNAs (miRNAs) have been addressed to participate in the pathogenesis and progression of thyroid cancer. However, it remains largely unknown what functions miR-30d may exert on thyroid cancer. This study, herein, aimed to identify the functional significance and machinery of miR-30d in the progression of thyroid cancer. MiR-30b presented aberrant low expression and ubiquitin-specific protease 22 (USP22) exhibited aberrant high expression in thyroid cancer tissues and cells. The current study proposed the possible machinery that miR-30d could target and negatively regulate USP22. Additionally, USP22 could enhance the stability of SIRT1 by inducing deubiquitination which consequently contributed to FOXO3a deacetylation-induced PUMA repression. Responding to the gain- or loss-of-function of miR-30d and/or USP22, behaviors of thyroid cancer cells were altered. Accordingly, miR-30d inhibited proliferation and promoted apoptosis of thyroid cancer cells by suppressing USP22 through SIRT1/FOXO3a/PUMA axis. The effects of miR-30d and USP22-mediated SIRT1/FOXO3a/PUMA axis on thyroid tumorigenesis were finally validated in murine models. We ultimately confirmed the anti-proliferative and pro-apoptotic effect of miR-30d via suppressing USP22 through in vivo findings. Conclusively, our findings highlight that the occurrence and progression of thyroid cancer can be suppressed by miR-30d-mediated inhibition of USP22 via the SIRT1/FOXO3a/PUMA axis, which provides a attractive therapeutic target for thyroid cancer treatment.

MiR-203a-3p, miR-204-3p, miR-222-3p as useful diagnostic and prognostic tool for thyroid neoplasia spectrum

PURPOSE

The challenge in the diagnosis and treatment of thyroid carcinoma is to correctly classify neoplasias with overlapping features and to identify the high-risk patients among those with a less aggressive form, in order to personalize the treatment of thyroid carcinoma patients accordingly.

METHODS

MiR-203a-3p, miR-204-3p, and miR-222-3p levels were determined in 99 cases of thyroid neoplasias (77 papillary thyroid carcinomas (PTC) of diverse variants, 12 follicular thyroid adenomas (FTA) and 10 nodular goiters (NG)) along with 99 adjacent non-malignant thyroid tissues using quantitative RT-PCR. The results were evaluated in comparison with the clinicopathological features of the patients and available TCGA data.

RESULTS

Down-regulated miR-203a-3p indicates the presence of thyroid tumor (PTC or FTA) with high sensitivity (75%) and specificity (73%), while its up-regulation indicates NG. If miR-203a-3p is down-regulated, up-regulated miR-204-3p with high sensitivity (83.3%) and specificity (74.4%) indicates FTA presence, while up-regulated miR-222-3p, with high sensitivity (76.6%) and specificity (75.0%), points to PTC. The expression of miR-204-3p and miR-222-3p depends on the PTC subtype (P < 0.05). While the deregulated expression of tested miRs is associated with a long-range of unfavorable clinicopathological parameters of PTC, only abundant expression of miR-222-3p may be used as an independent predictive factor for the presence of extrathyroid invasion and advanced pTNM stage of PTC (P < 0.05).

CONCLUSION

Successive evaluation of miR-203a-3p, miR-204-3p, and miR-222-3p expression can help in the differential diagnosis of thyroid neoplasias. A high relative value of miR-222-3p expression is an independent predictive factor for the presence of extrathyroid invasion and advanced pTNM stage of PTC. The panel consisting of miR-203a-3p, miR-204-3p, and miR-222-3p could be used as a diagnostic and prognostic tool for personalizing the treatment of thyroid cancer patients.

The role of miR-200 family in the regulation of hallmarks of cancer

MiRNAs are short non-coding RNAs that regulate gene expression post-transcriptionally contributing to the development of different diseases including cancer. The miR-200 family consists of five members, miR-200a, miR-200b, miR-200c, miR-141, and miR-429. Their expression is dysregulated in cancer tissue and their level is altered in the body fluids of cancer patients. Moreover, the levels of miR-200 family members correlate with clinical parameters such as cancer patients' survival which makes them potentially useful as diagnostic and prognostic biomarkers. MiRNAs can act as either oncomiRs or tumor suppressor miRNAs depending on the target genes and their role in the regulation of key oncogenic signaling pathways. In most types of cancer, the miR-200 family acts as tumor suppressor miRNA and regulates all features of cancer. In this review, we summarized the expression pattern of the miR-200 family in different types of cancer and their potential utility as biomarkers. Moreover, we comprehensively described the role of miR-200 family members in the regulation of all hallmarks of cancer proposed by Hanahan and Weinberg with the focus on the epithelial-mesenchymal transition, invasiveness, and metastasis of tumor cells.

Expression Profile and Diagnostic Significance of MicroRNAs in Papillary Thyroid Cancer

The incidence of papillary thyroid cancer (PTC) has increased in recent years. To improve the diagnostic management of PTC, we propose the use of microRNAs (miRNAs) as a biomarker. Our aim in this study was to evaluate the miRNA expression pattern in PTC using NanoString technology. We identified ten miRNAs deregulated in PTC compared with reference tissue: miR-146b-5p, miR-221-3p, miR-221-5p, miR-34-5p, miR-551b-3p, miR-152-3p, miR-15a-5p, miR-31-5p, and miR-7-5p (FDR < 0.05; |fold change (FC)| ≥ 1.5). The gene ontology (GO) analysis of differentially expressed miRNA (DEM) target genes identified the predominant involvement of epidermal growth factor receptor (EGFR), tyrosine kinase inhibitor resistance, and pathways in cancer in PTC. The highest area under the receiver operating characteristic (ROC) curve (AUC) for DEMs was found for miR-146-5p (AUC = 0.770) expression, indicating possible clinical applicability in PTC diagnosis. The combination of four miRNAs (miR-152-3p, miR-221-3p, miR-551b-3p, and miR-7-5p) showed an AUC of 0.841. Validation by real-time quantitative polymerase chain reactions (qRT-PCRs) confirmed our findings. The introduction of an miRNA diagnostic panel based on the results of our study may help to improve therapeutic decision making for questionable cases. The use of miRNAs as biomarkers of PTC may become an aspect of personalized medicine.

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

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

Recurrence of Papillary Thyroid Cancer: A Systematic Appraisal of Risk Factors

CONTEXT

Thyroid cancer recurrence is associated with increased mortality and adverse outcomes. Recurrence risk is currently predicted using clinical tools, often restaging patients after treatment. Detailed understanding of recurrence risk at disease onset could lead to personalized and improved patient care.

OBJECTIVE

We aimed to perform a comprehensive bioinformatic and experimental analysis of 3 levels of genetic change (mRNA, microRNA, and somatic mutation) apparent in recurrent tumors and construct a new combinatorial prognostic risk model.

METHODS

We analyzed The Cancer Genome Atlas data (TCGA) to identify differentially expressed genes (mRNA/microRNA) in 46 recurrent vs 455 nonrecurrent thyroid tumors. Two exonic mutational pipelines were used to identify somatic mutations. Functional gene analysis was performed in cell-based assays in multiple thyroid cell lines. The prognostic value of genes was evaluated with TCGA datasets.

RESULTS

We identified 128 new potential biomarkers associated with recurrence, including 40 mRNAs, 39 miRNAs, and 59 genetic variants. Among differentially expressed genes, modulation of FN1, ITGα3, and MET had a significant impact on thyroid cancer cell migration. Similarly, ablation of miR-486 and miR-1179 significantly increased migration of TPC-1 and SW1736 cells. We further utilized genes with a validated functional role and identified a 5-gene risk score classifier as an independent predictor of thyroid cancer recurrence.

CONCLUSION

Our newly proposed risk model based on combinatorial mRNA and microRNA expression has potential clinical utility as a prognostic indicator of recurrence. These findings should facilitate earlier prediction of recurrence with implications for improving patient outcome by tailoring treatment to disease risk and increasing posttreatment surveillance.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Analysis of serum microRNA in exosomal vehicles of papillary thyroid cancer

PURPOSE

In this study, we investigated the profile of microRNAs (miRNAs) contained in exosomes secreted in the serum of patients with papillary thyroid cancer (PTC).

METHODS

Exosome were isolated by adding ExoQuick Exosome Precipitation Solution. Dynamic light scattering (DLS) and western blotting analysis were used to ensure the quality of exosomes. The expression levels of miRNAs were investigated using custom-designed TaqMan Advanced miRNA Array Cards in the screening cohort and using specific TaqMan Advanced MicroRNA Assays in the validation cohort.

RESULTS

We identified miR24-3p, miR146a-5p, miR181a-5p and miR382-5p with different expression levels in two different series of 56 and 58 PTC patients as compared with healthy controls. Significant differences in the expression of three PTC exosomal miRNAs, depending on the presence of lymph node metastasis, were detected in only one PTC series. When comparing the expression levels of some PTC-specific exosomal miRNAs with those of the same miRNAs circulating free of any encapsulation, we found a significant correlation for only miR24-3p, suggesting that only select miRNAs are secreted in exosomes.

CONCLUSIONS

Our findings demonstrate that four miRNAs are differently secreted in the exosomes of PTC patients, whereas no conclusive results were found to characterize PTCs with lymph node metastasis, suggesting caution in the use of circulating exosomal miRNA expression levels as lymph node metastasis biomarkers. Further investigation into the mechanisms governing miRNA secretion in tumor cells are required.

miRNA-144-5p/ITGA3 Suppressed the Tumor-Promoting Behaviors of Thyroid Cancer Cells by Downregulating ITGA3

Objective

To ascertain the mechanism of miRNA-144-5p and ITGA3 in thyroid cancer (TC).

Methods

From The Cancer Genome Atlas (TCGA), RNA expression profiles were obtained for the expression analysis of miRNAs and mRNAs in TC. qRT-PCR and western blot were utilized to measure the expression of miRNA-144-5p and ITGA3 at RNA and protein levels, respectively. The association between miRNA-144-5p and ITGA3 was validated by the dual-luciferase assay. CCK-8, scratch healing, transwell, and flow cytometry assays were employed to evaluate tumor-related cell behaviors.

Results

Low-expressed miRNA-144-5p and high-expressed ITGA3 were found in TC cells relative to normal cells. miRNA-144-5p expression was positively associated with suppressive effects on proliferative, invasive, and migratory ability of TC cells while negatively associated with cell apoptosis. miRNA-144-5p inhibited ITGA3 expression in TC, and its overexpression remarkably reversed the tumor-promoting effects of overexpressed ITGA3 on the biological functions of TC.

Conclusion

It is verified in our study that cell growth of TC is inhibited by the miRNA-144-5p/ITGA3 axis, which represents an underlying target for TC. This research proposed a new insight into the strategy of TC treatment.

The Importance of miRNA in the Diagnosis and Prognosis of Papillary Thyroid Cancer

In recent years, the global incidence of thyroid cancer has been increasing. Despite the significant progress in the diagnostic tools applied for papillary thyroid cancer (PTC) diagnosis, commonly used methods require undergoing invasive diagnostic procedures, such as liquid biopsy, which still, in some cases, remains imprecise. In this case, novel screening and diagnostic biomarkers are still being evaluated using highly specialized techniques, which could increase PTC detection. Currently, a number of genes and proteins associated with PTC development are currently under investigation to assess their clinical utility. Accordingly, a literature search was undertaken to collect novel information about the diagnosis of and prognosis for PTC with a particular emphasis on the role of microRNA (miRNA) evaluation. The early identification of novel biomarkers is essential for facilitating appropriate therapeutic decisions. Moreover, the evaluation of plasma- and serum-derived miRNA measurements could be considered as equivalent thyroid cancer screening tools in the future. On the other hand, the PTC pathogenesis could be evaluated further with the use of miRNA evaluation, which may bring novel insights for potential medical target determination.

MicroRNA-Based Risk Score for Predicting Tumor Progression Following Radioactive Iodine Ablation in Well-Differentiated Thyroid Cancer Patients: A Propensity-Score Matched Analysis

Simple Summary

The three-tiered American Thyroid Association (ATA) risk stratification helps clinicians tailor decisions regarding follow-up modalities and the need for postoperative radioactive iodine (RAI) ablation and radiotherapy. However, a significant number of well-differentiated thyroid cancers (DTC) progress after treatment. Current follow-up modalities have also been proposed to detect disease relapse and recurrence but have failed to be sufficiently sensitive or specific to detect, monitor, or determine progression. Therefore, we assessed the predictive accuracy of the microRNA-based risk score in DTC with and without postoperative RAI. We confirm the prognostic role of triad biomarkers (miR-2f04, miR-221, and miR-222) with higher sensitivity and specificity for predicting disease progression than the ATA risk score. Compared to indolent tumors, a higher risk score was found in progressive samples and was associated with shorter survival. Consequently, our prognostic microRNA signature and nomogram provide a clinically practical and reliable ancillary measure to determine the prognosis of DTC patients.

Abstract

To identify molecular markers that can accurately predict aggressive tumor behavior at the time of surgery, a propensity-matching score analysis of archived specimens yielded two similar datasets of DTC patients (with and without RAI). Bioinformatically selected microRNAs were quantified by qRT-PCR. The risk score was generated using Cox regression and assessed using ROC, C-statistic, and Brier-score. A predictive Bayesian nomogram was established. External validation was performed, and causal network analysis was generated. Within the eight-year follow-up period, progression was reported in 51.5% of cases; of these, 48.6% had the T1a/b stage. Analysis showed upregulation of miR-221-3p and miR-222-3p and downregulation of miR-204-5p in 68 paired cancer tissues (p < 0.001). These three miRNAs were not differentially expressed in RAI and non-RAI groups. The ATA risk score showed poor discriminative ability (AUC = 0.518, p = 0.80). In contrast, the microRNA-based risk score showed high accuracy in predicting tumor progression in the whole cohorts (median = 1.87 vs. 0.39, AUC = 0.944) and RAI group (2.23 vs. 0.37, AUC = 0.979) at the cutoff >0.86 (92.6% accuracy, 88.6% sensitivity, 97% specificity) in the whole cohorts (C-statistics = 0.943/Brier = 0.083) and RAI subgroup (C-statistic = 0.978/Brier = 0.049). The high-score group had a three-fold increased progression risk (hazard ratio = 2.71, 95%CI = 1.86–3.96, p < 0.001) and shorter survival times (17.3 vs. 70.79 months, p < 0.001). Our prognostic microRNA signature and nomogram showed excellent predictive accuracy for progression-free survival in DTC.

miR-671-5p repressed progression of papillary thyroid carcinoma via TRIM14

The pivotal role of dysregulated miRNAs in development of papillary thyroid carcinoma has been emphasized in recent research. miR-671-5p was previously documented to function as a tumor suppressor. However, the role and mechanism of miR-671-5p in progression of papillary thyroid carcinoma remain to be further studied. Data from functional assays indicated that forced expression of miR-671-5p decreased cell viability, repressed cell proliferation, migration, and invasion in papillary thyroid carcinoma cells. In vivo study showed that miR-671-5p overexpression inhibited tumor growth, downregulated Ki67, and decreased tumor volume and weight. Tripartite motif containing 14 (TRIM14) was verified as downstream target of miR-671-5p. The expression of TRIM14 was suppressed by miR-671-5p in papillary thyroid carcinoma. Overexpression of TRIM14 increased cell viability, and promoted the proliferation, migration, and invasion of papillary thyroid carcinoma. Moreover, TRIM14 counteracted the suppressive effect of miR-671-5p overexpression on papillary thyroid carcinoma cell growth. In conclusion, miR-671-5p repressed progression of papillary thyroid carcinoma through downregulation of TRIM14, providing a promising target for therapy of papillary thyroid carcinoma.

Transcription factor SP1-induced microRNA-146b-3p facilitates the progression and metastasis of colorectal cancer via regulating FAM107A

BACKGROUND

Recent studies have provided compelling evidence regarding the association of microRNAs (miRNAs) with the progression and development of tumors. Among the miRNAs, the dysregulation of miR-146b-3p expression has been reported in several cancers, however, its effect on colorectal cancer (CRC) remains unexplored. Many studies have suggested a close correlation between the transcription factor (TF)-miRNA signal and cancer. The present study explored the effects of TF-miR-146b-3p axis on CRC and elucidated its downstream regulatory molecule.

MATERIALS AND METHODS

The expression levels of miR-146b-3p in CRC tissues and cell lines were assessed via quantitative real-time polymerase chain reaction (qRT-PCR). The impact of miR-146b-3p on CRC cell proliferation, migration, and invasion were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cell proliferation assay and transwell migration and invasion assay. Additionally, the impact of miR-146b-3p on CRC cell cycle and apoptosis was investigated using flow cytometry. The targets of miR-146b-3p, predicted by miRWalk database, were verified using a dual-luciferase reporter system. The expression levels of TFs were detected using qRT-PCR. The effects of miR-146b-3p and SP1 on FAM107A expression were assessed by performing qRT-PCR and western blotting. Chromatin Immunoprecipitation (ChIP) Assay was performed and JASPAR database was utilized to explore the regulatory relationship between the SP1 and miR-146b-3p.

RESULTS

Increased expression of miR-146b-3p in CRC tissues and cell lines correlated with poor overall survival (OS). Upregulation of miR-146b-3p expression remarkably promoted the proliferation, migration, and invasion of CRC cells and suppressed their apoptosis. Furthermore, SP1 overexpression significantly elevated the miR-146b-3p expression, decreased the FAM107A expression, and promoted the G1/S transition. The miR-146b-3p overexpression also enhanced the effects of SP1 overexpression on CRC cell proliferation, migration, and invasion, whereas miR-146b-3p knockdown led to the opposite results.

CONCLUSION

Mechanistically, miR-146b-3p functions as an oncogene by directly targeting FAM107A. Our results highlight the critical regulatory role played by SP1-induced miR-146b-3p expression in CRC development. Our results suggest that SP1/miR-146b-3p/FAM107A axis may be a potential therapeutic target for CRC.

Phytochemicals in thyroid cancer: analysis of the preclinical studies

PURPOSE

In the search for novel effective compounds to use in thyroid cancer (TC) unresponsive to current treatment, attention has recently focused on plant-derived compounds with anticancer activity. In this review, we discuss the preclinical studies demonstrating phytochemical activity against thyroid cancer cells.

RESULTS/CONCLUSIONS

In particular, we describe their antiproliferative properties or ability to re-induce iodine retention, thus supporting their potential use as single agents or adjuvants in radioiodine-resistant thyroid cancer treatment.

The Role of Snail-1 in Thyroid Cancer-What We Know So Far

Thyroid carcinomas, despite the usually indolent behaviour and relatively good overall prognosis, show a high tendency to gain invasive phenotype and metastasise in some cases. However, due to a relatively slow progression, the exact mechanisms governing the metastatic process of thyroid carcinomas, including the epithelial-to-mesenchymal transition (EMT), are poorly described. One of the best-known regulators of cancer invasiveness is Snail-1-a zinc-finger transcription factor that plays a key role as an EMT inducer. More and more attention is being paid to the role of Snail with regard to thyroid cancer development. Apart from the obvious implications in the EMT process, Snail-1 plays an important role in the regulation of chemoresistance of the thyroid cells and cancer stem cell (CSC) formation, and it also interacts with miRNA specific to the thyroid gland. The aim of this review was to summarise the knowledge on Snail-1, especially in the context of thyroid oncogenesis.

Emerging roles and mechanisms of microRNA‑222‑3p in human cancer (Review)

MicroRNAs (miRNAs/miRs) are a class of small non‑coding RNAs that maintain the precise balance of various physiological processes through regulating the function of target mRNAs. Dysregulation of miRNAs is closely associated with various types of human cancer. miR‑222‑3p is considered a canonical factor affecting the expression and signal transduction of multiple genes involved in tumor occurrence and progression. miR‑222‑3p in human biofluids, such as urine and plasma, may be a potential biomarker for the early diagnosis of tumors. In addition, miR‑222‑3p acts as a prognostic factor for the survival of patients with cancer. The present review first summarizes and discusses the role of miR‑222‑3p as a biomarker for diverse types of cancers, and then focuses on its essential roles in tumorigenesis, progression, metastasis and chemoresistance. Finally, the current understanding of the regulatory mechanisms of miR‑222‑3p at the molecular level are summarized. Overall, the current evidence highlights the crucial role of miR‑222‑3p in cancer diagnosis, prognosis and treatment.

LINC01816 promotes the migration, invasion and epithelial‑mesenchymal transition of thyroid carcinoma cells by sponging miR‑34c‑5p and regulating CRABP2 expression levels

Thyroid carcinoma (THCA) is a common type of endocrine system cancer and its current clinical treatment method is surgical resection. Long non-coding RNAs (lncRNAs) have been revealed to serve important roles in a variety of complex human diseases. Therefore, determining the association between lncRNAs and diseases may provide novel insight into disease-related lncRNAs, with the aim of improving disease treatments and diagnoses. Long intergenic non-protein coding RNA 1816 (LINC01816) was identified to be associated with the survival of patients with colorectal cancer using the IDHI-MIRW method. The present study aimed to investigate the role and molecular mechanism of LINC01816 in THCA. Analysis of datasets from The Cancer Genome Atlas database revealed that the upregulation of LINC01816 expression levels was associated with a variety of cancer types. Reverse transcription-quantitative PCR analysis demonstrated that compared with the normal thyroid tissues, the expression levels of LINC01816 were upregulated in THCA tissues. The results of wound healing and Transwell assays, and western blotting demonstrated that the overexpression of LINC01816 could strengthen the invasive and migratory abilities of THCA cells and enhance epithelial-mesenchymal transition progression. Analysis using the starBase website and dual-luciferase reporter assays identified that microRNA (miR)-34c-5p was a target of LINC01816. The overexpression of miR-34c-5p could inhibit the invasive and migratory abilities of THCA cells, in addition to inhibiting the cellular retinoic acid binding protein 2 (CRABP2) overexpression-induced effects on invasion, migration and EMT processes. In conclusion, the findings of the present study indicated that LINC01816 may be capable of sponging miR-34c-5p to upregulate CRABP2 expression levels, which subsequently promoted the invasion, migration and EMT of THCA cells. Therefore, targeting the LINC01816/miR-34c-5p/CRABP2 pathway may be an effective therapeutic approach for patients with THCA.

Epigenetic signature associated with thyroid cancer progression and metastasis

Thyroid cancer is not among the top cancers in terms of diagnosis or mortality but it still ranks fifth among the cancers diagnosed in women. Infact, women are more likely to be diagnosed with thyroid cancer than the males. The burden of thyroid cancer has dramatically increased in last two decades in China and, in the United States, it is the most diagnosed cancer in young adults under the age of twenty-nine. All these factors make it worthwhile to fully understand the pathogenesis of thyroid cancer. Towards this end, microRNAs (miRNAs) have constantly emerged as the non-coding RNAs of interest in various thyroid cancer subtypes on which there have been numerous investigations over the last decade and half. This comprehensive review takes a look at the current knowledge on the topic with cataloging of miRNAs known so far, particularly related to their utility as epigenetic signatures of thyroid cancer progression and metastasis. Such information could be of immense use for the eventual development of miRNAs as therapeutic targets or even therapeutic agents for thyroid cancer therapy.

Selective Use of Radioactive Iodine Therapy for Papillary Thyroid Cancers With Low or Lower-Intermediate Recurrence Risk

CONTEXT

Current guidelines recommend a selective use of radioiodine treatment (RAI) for papillary thyroid cancer (PTC).

OBJECTIVE

This work aimed to determine how policy changes affect the use of RAI and the short-term outcomes of patients.

METHODS

A retrospective analysis of longitudinal data was conducted in an academic referral center of patients with nonaggressive PTC variants; no extrathyroidal invasion or limited to soft tissues, no distant metastases, and 5 or fewer central-compartment cervical lymph node metastases. In cohort 1, standard treatments were total thyroidectomy and RAI (May 2005-June 2011); in cohort 2 decisions on RAI were deferred for approximately 12 months after surgery (July 2011-December 2018). Propensity score matching was used to adjust for sex, age, tumor size, lymph node status, and extrathyroidal extension. Intervention included immediate RAI or deferred choice. Main outcome measures were responses to initial treatment during 3 or more years of follow-up.

RESULTS

In cohort 1, RAI was performed in 50 of 116 patients (51.7%), whereas in cohort 2, it was far less frequent: immediately in 10 of 156 (6.4%), and in 3 more patients after the first follow-up data. The frequencies of structural incomplete response were low (1%-3%), and there were no differences between the 2 cohorts at any follow-up visit. Cohort 2 patients had higher rates of "gray-zone responses" (biochemical incomplete or indeterminate response).

CONCLUSION

Selective use of RAI increases the rate of patients with "uncertain" status during early follow-up. The rate of structural incomplete responses remains low regardless of whether RAI is used immediately. Patients should be made aware of the advantages and drawbacks of omitting RAI.

Anti-oncogenic effects of SOX2 silencing on hepatocellular carcinoma achieved by upregulating miR-222-5p-dependent CYLD via the long noncoding RNA CCAT1

In this study, we determined the involvement of SOX2 and its downstream signaling molecules in hepatocellular carcinoma (HCC) progression. We carried out lentiviral transfection in HepG2 cells to determine the roles of SOX2, CCAT1, EGFR, miR-222-5p, and CYLD in HepG2 cells. We first determined the interaction between SOX2 and CCAT1 and that between miR-222-5p and CYLD and their effect on tumor growth in vivo was analyzed in HCC-xenograft bearing nude mice xenografts. SOX2 and CCAT1 were highly expressed in HCC tissues and HepG2 cells. SOX2 bound to the regulatory site of CCAT1. Silencing of SOX2 or CCAT1 inhibited HepG2 cell proliferation, migration, and invasion as well as decreased the expression of CCAT1 and EGFR. CCAT1 silencing reduced EGFR expression, but EGFR expression was increased in HCC tissues and HepG2 cells, which promoted proliferation, migration, and invasion in vitro. EGFR upregulated miR-222-5p, leading to downregulation of CYLD. miR-222-5p inhibition or CYLD overexpression repressed cell functions in HepG2 cells. SOX2 silencing decreased CCAT1, EGFR, and miR-222-5p expression but increased CYLD expression. Loss of SOX2 also reduced the growth rate of tumor xenografts. In summary, SOX2-mediated HCC progression through an axis involving CCAT1, EGFR, and miR-222-5p upregulation and CYLD downregulation.

Overexpression of miR-127 Predicts Poor Prognosis and Contributes to the Progression of Papillary Thyroid Cancer by Targeting REPIN1

Papillary thyroid cancer (PTC) is a major kind of thyroid cancer with increasing recurrence and metastasis. MiR-127 has been demonstrated to play roles in many cancers with dysregulation. However, the function of miR-127 is still unknown. This study aimed to explore a novel biomarker for the progression and prognosis of PTC. A set of 118 patients with PTC were collected from the Affiliated Hospital of Qingdao University. qRT-PCR was used to detect the expression of miR-127 in PTC tissues and cells. The association between miR-127 expression and the clinicopathological features of patients were evaluated by the χ² test, and the prognostic value of miR-127 was evaluated by Kaplan-Meier analysis and Cox regression analysis. The effect of miR-127 on cell proliferation, migration, and invasion of PTC was analyzed by CCK-8 and transwell assay. miR-127 was found to be upregulated in PTC tissues and cells correlated with the TNM stage and poor prognosis of PTC patients. MiR-127 and the TNM stage were considered as two independent prognostic indicators for PTC. Moreover, overexpression of miR-127 significantly enhanced cell proliferation, migration, and invasion of PTC by targeting REPIN1. miR-127 may be involved in the progression of PTC, which provides a new therapeutic strategy for PTC.

Molecular analysis of fine-needle aspiration cytology in thyroid disease: where are we?

PURPOSE OF REVIEW

The prevalence of thyroid nodules in the general population is high but only about 5% are malignant lesions. Cytology is usually appropriate to rule out malignancy in sonographically suspicious nodules but in many cases, reports are indeterminate. Molecular testing is a more recent approach to rule out malignancy and guide subsequent management.

RECENT FINDINGS

Although several different molecular testing approaches have proven useful in reducing unnecessary surgery, there are still several remaining issues, such as the possible occurrence of RAS mutations (which are difficult to interpret in clinical management) and the role of molecular analysis in specific histotypes, such as Hürthle cell carcinomas. Furthermore, conclusive evidence is lacking regarding the cost-effectiveness and appropriateness of surgical options following molecular tests.

SUMMARY

To be useful in clinical practice, molecular tests should be applied to appropriate candidates. In truly uncertain thyroid nodules in which diagnostic surgery may be considered, molecular testing may change the clinical approach and 'save' a number of thyroids.

A comprehensive expression profile of tRNA-derived fragments in papillary thyroid cancer

Background

The incidence of thyroid cancer has been on a rise. Papillary thyroid cancer (PTC) is the most common type of malignant thyroid tumor and accounts for approximately 85% of thyroid cancer cases. Although the genetic background of PTC has been studied extensively, relatively little is known about the role of small noncoding RNAs (sncRNAs) in PTC. tRNA‐derived fragments (tRFs) represent a newly discovered class of sncRNAs that exist in many species and play key roles in various biological processes.

Methods

In this study, we used high‐throughput next‐generation sequencing technology to analyze the expression of tRFs in samples from PTC tissues and normal tissues. We selected four tRFs to perform qPCR to determine the expression levels of these molecules and make bioinformatic predictions.

Results

We identified 53 unique tRFs and transfer RNA halves (tsRNAs). The 10 most upregulated tRFs and tsRNAs were tRF‐39‐I6D3887S1RMH5MI2, tRF‐21‐2E489B3RB, tRF‐18‐JMRPFQDY, tRF‐17‐202L2YF, tRF‐17‐VBY9PYJ, tRF‐18‐YRRHQFD2, tRF‐21‐WE884U1DD, tRF‐41‐EX2Z10I9BZBZOS4YB, tRF‐39‐HPDEXK7S1RNS9MI2, and tRF‐20‐1SS2P46I. The 10 most downregulated tRFs and tsRNAs were tRF‐31‐HQ9M739P8WQ0B, tRF‐43‐5YXENDBP1IUUK7VZV, tRF‐38‐RZYQHQ9M739P8WD8, tRF‐25‐9M739P8WQ0, tRF‐33‐V6Z3M8ZLSSXUD6, tRF‐27‐MY73H3RXPLM, tRF‐26‐DBNIB9I1KQ0, tRF‐38‐Z9HMI8W47W1R7HX, tRF‐40‐Z6V6Z3M8ZLSSXUOL, and tRF‐39‐YQHQ9M739P8WQ0EB. qPCR verification of cell lines and tissue samples yielded results consistent with the sequencing analysis. As tRF‐39 expression showed the maximum difference between PTC cells and normal cells, we chose this tRF to predict targets and perform functional tRF and tsRNA enrichment analysis.

Conclusion

In this study, we provided a comprehensive catalog of tRFs involved in PTC and assessed the abnormal expression of these fragments. Through qPCR verification, tRF‐39‐0VL8K87SIRMM12E2 was found to be the most significantly upregulated tRF. Further tRF and enrichment analysis revealed that tRF‐39 was mostly enriched in the “metabolic pathways.” These preliminary findings can be used as the basis for further research studies based on the functional role of tRFs in patients with PTC.

Extracellular MicroRNAs as Intercellular Mediators and Noninvasive Biomarkers of Cancer

Simple Summary

There are an extensive number of publications regarding the role of endogenous miRNAs as regulators of gene expression in cancer. However, extracellular miRNAs have emerged as a novel mechanism of cell-to-cell communication in normal conditions and disease and have drawn a large amount of interest as regulators of gene expression and as potential non-invasive biomarkers in cancer. Despite this high interest and the abundance of research on the biology and role of extracellular miRNAs in cancer, they are not yet completely understood. The aim of this review is to highlight the relevant biological characteristics of extracellular miRNAs that enable them to function as intercellular mediators of gene expression regulation and provide the recently published evidence of the specific role of extracellular miRNAs in tumor development and progression.

Abstract

MicroRNAs (miRNAs) are released by different types of cells through highly regulated mechanisms under normal and pathological conditions. These extracellular miRNAs can be delivered into recipient cells for functional purposes, acting as cell-to-cell signaling mediators. It has been discovered that cancer cells release miRNAs into their surroundings, targeting normal cells or other cancer cells, presumably to promote tumor development and progression. These extracellular miRNAs are associated with oncogenic mechanisms and, because they can be quantified in blood and other bodily fluids, may be suitable noninvasive biomarkers for cancer detection. This review summarizes recent evidence of the role of extracellular miRNAs as intercellular mediators, with an emphasis on their role in the mechanisms of tumor development and progression and their potential value as biomarkers in solid tumors. It also highlights the biological characteristics of extracellular miRNAs that enable them to function as regulators of gene expression, such as biogenesis, gene silencing mechanisms, subcellular compartmentalization, and the functions and mechanisms of release.

An 8 miRNA-Based Risk Score System for Predicting the Prognosis of Patients With Papillary Thyroid Cancer

Background:

Dysregulation of microRNAs (miRNAs) in papillary thyroid cancer (PTC) might influence prognosis of PTC. This study is aimed to develop a risk score system for predicting prognosis of PTC.

Methods:

The miRNA and gene expression profiles of PTC were obtained from The Cancer Genome Atlas database. PTC samples were randomly separated into training set (n = 248) and validation set (n = 248). The differentially expressed miRNAs (DE-miRNAs) in the training set were screened using limma package. The independent prognosis-associated DE-miRNAs were identified for building a risk score system. Risk score of PTC samples in the training set was calculated and samples were divided into high risk group and low risk group. Kaplan-Meier curves and receiver operating characteristic (ROC) curve were used to assess the accuracy of the risk score system in the training set, validation set and entire set. Finally, a miRNA-gene regulatory network was visualized by Cytoscape software, followed by enrichment analysis.

Results:

Totally, 162 DE-miRNAs between tumor and control groups in the training set were identified. An 8 independent prognosis-associated DE-miRNAs, (including miR-1179, miR-133b, miR-3194, miR-3912, miR-548j, miR-6720, miR-6734, and miR-6843) based risk score system was developed. The area under ROC curve in the training set, validation set and entire set was all above 0.93. A miRNA-gene regulatory network involving the 8 DE-miRNAs were built and functional enrichment analysis suggested the genes in the network were significantly enriched into 13 pathways, including calcium signaling pathway and hedgehog signaling pathway.

Conclusion:

The risk score system developed this study might be used for predicting the prognosis of PTC. Besides, the 8 miRNAs might affect the prognosis of PTC via hedgehog signaling pathway and calcium signaling pathway.

The Prognostic Value of MicroRNAs in Thyroid Cancers-A Systematic Review and Meta-Analysis

Thyroid cancer (TC) includes various phenotypes, from indolent to highly aggressive cancer. The limitations of the current prognostication systems to predict the recurrence risk and the variability in expression of the genes involved in the thyroid carcinogenesis uncover the need for new prognostic biomarkers by taking into account potential epigenetic differences. We aimed to summarize the current knowledge regarding the prognostic impact of microRNAs (miRNAs) in TC. A literature search was conducted in PubMed, Embase, Scopus, and Web of Science databases. Both upregulated and downregulated miRNAs are significantly correlated with worse overall survival (hazard ratio (HR) = 5.94, 95% CI: 2.73-12.90, p < 0.001; HR = 0.51, 95% CI: 0.26-0.96, p = 0.048) disease/recurrence-free survival (HR = 1.58, 95% CI: 1.08-2.32, p = 0.003; HR = 0.37, 95%, CI: 0.24-0.60, p < 0.001). Sensitivity analysis revealed a significant association between the higher expression of miR-146b, miR-221, and miR-222 and the recurrence of papillary TC (OR = 9.11, 95% CI 3.00 to 27.52; p < 0.001; OR = 3.88, 95% CI 1.34 to 11.19, p < 0.001; OR = 6.56, 95% CI 2.75 to 15.64, p < 0.001). This research identified that miR-146b, miR-221, and miR-222 could serve as potential prognostic biomarkers in TC, particularly in PTC. Further studies are needed to strengthen these findings and sustain its clinical applicability.

Reciprocal Dysregulation of MiR-146b and MiR-451 Contributes in Malignant Phenotype of Follicular Thyroid Tumor

Over the last few years, incidental thyroid nodules are being diagnosed with increasing frequency with the use of highly sensitive imaging techniques. The ultrasound thyroid gland examination, followed by the fine-needle aspiration cytology is the standard diagnostic approach. However, in cases of the follicular nature of nodules, cytological diagnosis is not enough. Analysis of miRNAs in the biopsy presents a promising approach. Increasing our knowledge of miRNA's role in follicular carcinogenesis, and development of the appropriate the miRNA analytical technologies are required to implement miRNA-based tests in clinical practice. We used material from follicular thyroid nodes (n.84), grouped in accordance with their invasive properties. The invasion-associated miRNAs expression alterations were assayed. Expression data were confirmed by highly sensitive two-tailed RT-qPCR. Reciprocally dysregulated miRNAs pair concentration ratios were explored as a diagnostic parameter using receiver operation curve (ROC) analysis. A new bioinformatics method (MiRImpact) was applied to evaluate the biological significance of the observed expression alterations. Coupled experimental and computational approaches identified reciprocal dysregulation of miR-146b and miR-451 as important attributes of follicular cell malignant transformation and follicular thyroid cancer progression. Thus, evaluation of combined dysregulation of miRNAs relevant to invasion and metastasis can help to distinguish truly malignant follicular thyroid cancer from indolent follicular adenoma.

Molecular Markers Guiding Thyroid Cancer Management

The incidence of thyroid cancer is rapidly increasing, mostly due to the overdiagnosis and overtreatment of differentiated thyroid cancer (TC). The increasing use of potent preclinical models, high throughput molecular technologies, and gene expression microarrays have provided a deeper understanding of molecular characteristics in cancer. Hence, molecular markers have become a potent tool also in TC management to distinguish benign from malignant lesions, predict aggressive biology, prognosis, recurrence, as well as for identification of novel therapeutic targets. In differentiated TC, molecular markers are mainly used as an adjunct to guide management of indeterminate nodules on fine needle aspiration biopsies. In contrast, in advanced thyroid cancer, molecular markers enable targeted treatments of affected signalling pathways. Identification of the driver mutation of targetable kinases in advanced TC can select treatment with mutation targeted tyrosine kinase inhibitors (TKI) to slow growth and reverse adverse effects of the mutations, when traditional treatments fail. This review will outline the molecular landscape and discuss the impact of molecular markers on diagnosis, surveillance and treatment of differentiated, poorly differentiated and anaplastic follicular TC.

Analytical validation of a novel targeted next-generation sequencing assay for mutation detection in thyroid nodule aspirates and tissue

PURPOSE

The identification of somatic mutations in cancer specimens enables detection of molecular markers for personalized treatment. We recently developed a novel molecular assay and evaluated its clinical performance as an ancillary molecular method for indeterminate thyroid nodule cytology. Herein we describe the analytical validation of the novel targeted next-generation sequencing (NGS) assay in thyroid samples from different sources.

METHODS

We present validation data of a novel NGS-based panel on 463 thyroid samples, including 310 fine-needle aspiration (FNA) specimens from different sources (FNA collected in preservative solution, liquid-based, and stained smears), 10 fresh frozen, and 143 formalin-fixed paraffin-embedded (FFPE) thyroid tissue specimens. Sequencing performance in the different samples was evaluated along with reproducibility, repeatability, minimum nucleic acid input to detect variants, and analytical sensitivity of the assay.

RESULTS

All thyroid samples achieved high sequencing performance, with a mean base coverage depth ranging from 2228 × (in liquid-based FNA) to 3661 × (in FNA stained smears), and coverage uniformity ranging from 86% (in FFPE) to 95% (in FNA collected in preservative solution), with all target regions covered above the minimum depth required to call a variant (500×). The minimum nucleic acid input was 1 ng. Analytic sensitivity for mutation detection was 2-5% mutant allele frequency.

CONCLUSIONS

This validation study of a novel NGS-based assay for thyroid nodules demonstrated that the assay can be reliably used on multiple thyroid sample types, including FNA from different sources and FF and FFPE thyroid samples, thus providing a robust and reliable assay to genotype thyroid nodules, which may improve thyroid cancer diagnosis and care.

Downregulation of miR-140 is Correlated with Poor Prognosis and Progression of Thyroid Cancer

BACKGROUND

The incidence of thyroid cancer is increasing rapidly and there is an urgent need to explore novel therapeutic targets for thyroid cancer. MiR-140 has been reported to affect the progression of various cancers, which makes it possible to play a role in thyroid cancer. This study aimed to investigate the expression and role of miR-140 in thyroid cancer.

METHODS

The expression of miR-140 was investigated by reverse transcription-quantitative polymerase chain reaction (qRT-PCR) in thyroid cancer tissues and cell lines. The prognostic value of miR- 140 in thyroid cancer was evaluated by Kaplan-Meier survival and Cox regression. Moreover, the effects of miR-140 on cell proliferation, migration, and invasion of thyroid cancer were investigated by CCK-8 and Transwell assay.

RESULTS

MiR-140 was downregulated in thyroid cancer tissues and cells, which correlated with TNM stage and lymph node metastasis of patients. Patients with low miR-140 expression had a shorter survival time compared with that in patients with high miR-140 expression. Furthermore, miR-140 acts as an independent factor for the prognosis of thyroid cancer. Overexpression of miR-140 inhibited cell proliferation, migration, and invasion of thyroid cancer.

CONCLUSION

MiR-140 can serve as a potential prognostic factor for patients with thyroid cancer and suppress the progression of thyroid cancer, which provides new insight for the therapeutic target for thyroid cancer.

The role of microRNAs in the pathogenesis of thyroid cancer

Thyroid cancer is the most frequent type of cancers originating from the endocrine system. Early diagnosis leads to good clinical outcome in differentiated types of thyroid cancer. Yet, there are few treatment options for patients with medullary or anaplastic thyroid cancer. Thus, identification of molecular markers that explain the pathologic process during evolution of this cancer has practical significance. MicroRNAs (miRNAs) have been shown to influence the activity of thyroid cancer-related signaling pathways such as MAPK pathway and RET gene. These small transcripts not only can differentiate malignant tissues from non-malignant tissues, but also have differential expression in different stages of thyroid cancer. Assessment of serum levels of miRNAs is a practical noninvasive method for follow-up of patients after thyroidectomy. Moreover, the therapeutic effects of a number of miRNAs have been verified in xenograft models of thyroid cancer. In the current review, we summarize the data regarding the role of miRNAs in thyroid cancer.

Knockdown of the long noncoding RNA XIST suppresses glioma progression by upregulating miR-204-5p

Background: Gliomas are the most prevalent primary malignant tumors of the central nervous system. Our previous study showed that miR-204-5p is a tumor suppressor gene in glioma. Bioinformatic analyses suggest that long noncoding RNA (lncRNA) X-inactive specific transcript (XIST) is a potential target gene of miR-204-5p.

Methods: We analyzed the expression of XIST and miR-204-5p in glioma tissues and the correlation with glioma grade. A series of in vitro experiments were carried out to elucidate the role of XIST in glioma progression. A mouse xenograft model was established to detect whether knockdown of XIST can inhibit glioma growth. A luciferase assay was performed to determine whether XIST can bind to miR-204-5p and the binding specificity. Cells stably expressing shXIST or shNC were transfected with anti-miR-204-5p or anti-miR-204-5p-NC to evaluate whether XIST mediates the tumor-suppressive effects of miR-204-5p.

Results: XIST was upregulated in glioma tissues compared with normal brain tissues (NBTs), while miR-204-5p expression was significantly decreased in glioma tissues compared with NBTs. Both XIST and miR-204-5p expression levels were clearly related to glioma grade, and the expression of XIST was obviously negatively correlated with miR-204-5p expression. Knockdown of XIST inhibited glioma cell proliferation, migration, and invasion, promoted apoptosis of glioma cells, inhibited tumor growth and increased the survival time in nude mice. miR-204-5p could directly bind to XIST and negatively regulate XIST expression. XIST mediated glioma progression by targeting miR-204-5p in glioma cells. XIST crosstalk with miR-204-5p regulated Bcl-2 expression to promote apoptosis.

Conclusion: Our results provide evidence that XIST, miR-204-5p and Bcl-2 form a regulatory axis that controls glioma progression and can serve as a potential therapeutic target for glioma.

Performance of a dual-component molecular assay in cytologically indeterminate thyroid nodules

PURPOSE

Deciding whether patients with a cytologically indeterminate thyroid nodule should be referred for surgery or for active surveillance is an important challenge for clinicians. The aim of this study was to evaluate the performance of a novel dual-component molecular assay as an ancillary molecular method for resolving indeterminate thyroid nodule cytology.

METHODS

We selected 156 thyroid nodules from those that had undergone fine-needle aspiration processed by liquid-based cytology and surgical resection between June 2016 and December 2017. The sample set included 63 nodules cytologically classified as indeterminate, and 93 other nodules randomly selected from those with non-diagnostic, benign, suspicious, or malignant cytology. Nucleic acids from each nodule were subjected to next-generation sequencing analysis for mutation detection in 23 genes and to digital polymerase chain reaction (PCR) evaluation for miR-146b-5p expression levels.

RESULTS

Used alone, mutation analysis in the indeterminate subset (cancer prevalence: 22.5%) displayed high sensitivity (89%) and NPV (96%). In contrast, the miR-146b-5p assay offered high specificity (93%) and PPV (93%). Combined use of both analyses improved panel performance by eliminating false-negative results.

CONCLUSIONS

These preliminary data suggest that a dual-component molecular test can increase the diagnostic accuracy of thyroid cytology alone by reducing the number of nodules that will be classified as indeterminate and increasing those that can be reliably classified as benign. If these findings are confirmed, this test can be considered for use in clinical practice and is expected to reduce diagnostic surgery and health care costs, and to improve patient quality of life.

miR-26b-5p Inhibits the Proliferation, Migration and Invasion of Human Papillary Thyroid Cancer in a β-Catenin-Dependent Manner

Background

miR-26b-5p is reported to be involved in the progression of multiple cancers, but its function and mechanism in human papillary thyroid cancer (PTC) remain unknown. We aimed to uncover the function and mechanism of miR-26b-5p in PTC.

Methods

We performed qRT-PCR to detect the differences in miR-26b-5p expression between normal tissue and PTC. In vitro, we established cell lines stably overexpressing miR-26b-5p and investigated the function and underlying mechanism of miR-26b-5p in PTC.

Results

miR-26b-5p was downregulated in PTC compared with normal tissue. miR-26b-5p was correlated with the clinical stage. miR-26b-5p inhibited the proliferation, invasion and migration of PTC cell lines. We next detected EMT and proliferation markers. miR-26b-5p was shown to exert its function in a β-catenin-dependent manner.

Conclusion

Taken together, our results showed that miR-26b-5p inhibits proliferation, migration, invasion and EMT by degrading β-catenin.

Plasma Exosomal miR-146b-5p and miR-222-3p are Potential Biomarkers for Lymph Node Metastasis in Papillary Thyroid Carcinomas

Background

Lymph node metastasis (LNM) is associated with increased risk of recurrence and poor prognosis in papillary thyroid cancer (PTC). Novel non-invasive biomarkers for the prediction of LNM in PTC patients are still urgently needed. In this study, the relationship between the expression of plasma exosomal microRNAs (miRNAs) and LNM was analyzed. Further, we aimed to explore if exosomal miRNAs can serve as indicators of LNM in PTC patients.

Methods

A total of 64 PTC patients who underwent total thyroidectomy and neck dissection from June 2018 to July 2018 in West China Hospital were enrolled in this study. Plasma exosomes were isolated by exoRNeasy Serum/Plasma Maxi Kit. The levels of selected exosomal miRNAs were detected by real-time quantitative PCR (qRT-PCR). Cox proportional hazard analyses and receiver operating characteristic (ROC) curves were conducted to evaluate the predictive efficiency. Furthermore, PTC cell lines with transfection of miRNA mimics/inhibitors were used to verify the functions of exosomal miRNAs.

Results

49 PTC patients with LNM and 15 without LNM were included in the present study. Exosomal miR-146b-5p and miR-222-3p were both significantly upregulated in patients with LNM (P values were 0.008 and 0.015, respectively). ROC analyses revealed that the areas under the curves (AUCs) of miR-146b-5p and miR-222-3p for LNM prediction were 0.811 and 0.834, respectively. Moreover, the AUC increased to 0.895 when the two miRNAs used together. Wound healing assays and transwell assays showed that miR-146b-5p and miR-222-3p significantly enhanced the migration and invasion ability of PTC cells in vitro.

Conclusion

Plasma exosomal miR-146b-5p and miR-222-3p could serve as potential biomarkers for LNM in PTC.

Exosomes as Mediators of Cell-to-Cell Communication in Thyroid Disease

Exosomes are a type of extracellular vehicle, formed by budding cell membranes, containing proteins, DNA, and RNA. Concentrated cargoes from parent cells are enveloped in exosomes, which are cell specific and may have functions in the recipient cell, reflecting a novel physiological and pathological mechanism in disease development. As a transmitter, exosomes shuttle to different cells or tissues and mediate communications among these organelles. To date, several studies have demonstrated that exosomes play crucial roles in disease pathogenesis and development, such as breast and prostate cancer. However, studies investigating connections between exosomes and thyroid disease are limited. In this review, recent research advances on exosomes in thyroid cancer and Graves' disease are reviewed. These studies suggest that exosomes are involved in thyroid disease and appear as impressive potentials in thyroid therapeutic areas.

Update on Fundamental Mechanisms of Thyroid Cancer

The incidence of thyroid cancer (TC) has increased worldwide over the past four decades. TC is divided into three main histological types: differentiated (papillary and follicular TC), undifferentiated (poorly differentiated and anaplastic TC), and medullary TC, arising from TC cells. This review discusses the molecular mechanisms associated to the pathogenesis of different types of TC and their clinical relevance. In the last years, progresses in the genetic characterization of TC have provided molecular markers for diagnosis, risk stratification, and treatment targets. Recently, papillary TC, the most frequent form of TC, has been reclassified into two molecular subtypes, named BRAF-like and RAS-like, associated to a different range of cancer risks. Similarly, the genetic characterization of follicular TC has been proposed to complement the new histopathological classification in order to estimate the prognosis. New analyses characterized a comprehensive molecular profile of medullary TC, raising the role of RET mutations. More recent evidences suggested that immune microenvironment associated to TC may play a critical role in tumor invasion, with potential immunotherapeutic implications in advanced and metastatic TC. Several types of ancillary approaches have been developed to improve the diagnostic value of fine needle aspiration biopsies in indeterminate thyroid nodules. Finally, liquid biopsy, as a non-invasive diagnostic tool for body fluid genotyping, brings a new prospective of disease and therapy monitoring. Despite all these novelties, much work remains to be done to fully understand the pathogenesis and biological behaviors of the different types of TC and to transfer this knowledge in clinical practice.

MiR-599 serves a suppressive role in anaplastic thyroid cancer by activating the T-cell intracellular antigen

Anaplastic thyroid cancer (ATC) has a mean survival time of 6 months and accounts for 1-2% of all thyroid tumors. Understanding the underlying molecular mechanisms of carcinogenesis and progression in ATC would contribute to the identification of novel therapeutic targets. A previous study revealed that microRNA (miR)-599 was associated with tumor initiation and development in certain types of cancer. However, the specific functions and mechanisms of miR-599 in ATC are poorly understood. The objective of the present study was to identify its expression, function and molecular mechanism in ATC. The expression levels of miR-599 in 10 pairs of surgical specimens and human ATC cell lines were examined by reverse transcription-quantitative polymerase chain reaction. Function assays illustrated that miR-599 overexpression not only suppressed KAT-18 cell viability, proliferation and metastasis in vitro and decreased tumor growth in the tumor xenograft model but also induced cell apoptosis. Furthermore, T-cell intracellular antigen (TIA1), a tumor suppressor, was confirmed as a direct target of miR-599. It was demonstrated that TIA1 silencing rescued the inhibitory effect of migration and invasion induced by the overexpression of miR-599 in KAT-18 cells. In conclusion, the present study revealed that miR-599 inhibited ATC cell growth and metastasis via activation of TIA1. Therefore miR-599 may be a novel molecular therapeutic target for ATC.

miRNA-15a regulates the proliferation and apoptosis of papillary thyroid carcinoma via regulating AKT pathway

Aim

Aberrantly expressed microRNAs (miRNAs) are involved in many diseases including cancer. The expression of miR-15a was reported to be downregulated in papillary thyroid carcinoma (PTC) compared to control tissue. However, the mechanism underlying this downregulation remains unclear.

Methods

The effects of miR-15a on the proliferation and invasion of PTC cells were evaluated by CCK-8 and transwell assays, respectively. Expression levels of AKT and rearranged during transfection (RET) in cells were assessed using Western blotting. The correlation of RET and miR-15a was validated by luciferase reporter assay. Moreover, in vivo assay was performed to demonstrate the effect of miR-15a on tumor growth.

Results

We confirmed that the expression of miR-15a was significantly lower in PTC tissue than that in normal tissue. Overexpression of miR-15a notably inhibited PTC cell proliferation and invasion via promoting apoptosis. Additionally, RET was found to be a target of miR-15a and this correlation was confirmed by dual-luciferase assay and Western blot. Furthermore, in vivo study revealed that overexpression of miR-15a inhibited tumor growth via downregulating the levels of RET and phosphorylated AKT.

Conclusion

In the present study, we demonstrated that miR-15a played an antitumor role in regulating PTC via targeting RET/AKT pathway. Therefore, miR-15a may serve as a potential molecular target for the treatment of PTC.

MiR-4500 Regulates PLXNC1 and Inhibits Papillary Thyroid Cancer Progression

Although most patients with papillary thyroid cancer (PTC) are curable, there are still a few patients showing poor outcomes and increased risk of secondary cancers after therapies. In this study, we aimed to investigate the correlation between miR-4500 and PTC and to explore its molecular functions. A total of 50 patients were included, and sonography and histological examinations were used for diagnosis. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied for detection of mRNA levels while Western blotting was used for measuring protein expression. Cell proliferation was tested using CCK-8 and colony formation assays. Caspase-3 activity and nucleosomal fragmentation assays were employed to test cell apoptosis. Cell invasive ability was measured using transwell assay. MiR-4500 target was identified using luciferase assay and RNA pull-down assay. MiR-4500 expression was significantly decreased in five PTC cell lines compared with Nthy-ori 3-1 cells and in PTC tissues compared with adjacent normal thyroid tissues, respectively. Decreased expression of miR-4500 showed lower survival rate, higher cancer stage, and lymphatic metastasis. Therefore, our results implied that miR-4500 could serve as a potential biomarker for PTC prognosis. Overexpression of miR-4500 repressed colony formation, proliferation, and invasiveness of PTC cells whereas increased cell apoptosis. We identified that PLXNC1 was a direct target of miR-4500. PLXNC1 knockdown showed similar effects on cell viability, colony formation, and cell apoptosis as overexpression of miR-4500 in PTC cells. In conclusion, miR-4500 inhibits the malignant transformation of PTC cells by directly targeting and repressing PLXNC1.

Evaluating pre- and post-operation plasma miRNAs of papillary thyroid carcinoma (PTC) patients in comparison to benign nodules

Background

Thyroid cancer is the most common endocrinology cancer that its incidence has increased in recent decades. miRNAs are new biomarkers in recent studies in the diagnosis and follow-up of these patients.

Methods

Blood and thyroid tissue samples were obtained from two groups of included patients (PTC and benign nodules), pre- and post-operation. miRNAs were extracted from these plasma samples and were measured quantitatively. After cDNA synthesis, qPCR was carried out. Then tissue samples were investigated, and their relation to miR expression was studied. These results were analyzed by paired- and independent samples t-test, and non-parametric tests.

Results

miR-222 and miR-181a declined in PTC patients before and after surgery, significantly (P < 0.001 for both groups), with no significant difference in control group before and after surgery (P = 0.61 for miR-222 and P = 0.06 for miR-181a). The difference between the two groups, pre-and post-operation, was statistically significant (P = 0.01 for miR-222 and P < 0.001 for miR-181a). Comparing case and control groups, pre- and post-operatively, yielded no significant difference, in miR-155-5p levels (P = 0.61 and P = 0.53, respectively). Comparing PTC and control groups before surgery showed a significant difference (P = 0.01), while no significant difference was observed comparing them after surgery, in miR146-a (P = 0.27). Our results depicted a higher miR-155-5p and miR-146a expression before surgery than after it (P < 0.001 in both groups, for both miRs). We found a significant relationship between miR-222 and BRAFV600E mutation and significantly higher levels of miR-181a with increasing tumor size in PTC patients.

Conclusion

miR-222 showed overexpression in all PTC cases, which is indicative of a relation between miRNA and PTC. Also, comparing miR-181 and miR-146a showed a significant difference between cancerous and benign cases. miR-155-5p as an inflammatory factor, showed no significant changes, comparing two groups.

Targeting EZH2 as a novel therapeutic strategy for sorafenib-resistant thyroid carcinoma

Thyroid carcinoma is the most common endocrine malignancy. Surgery, post‐operative selective iodine‐131 and thyroid hormone suppression were the most common methods for the therapy of thyroid carcinoma. Although most patients with differentiated thyroid carcinoma (DTC) showed positive response for these therapeutic methods, some patients still have to face the radioactive iodine (RAI)‐refractory problems. Sorafenib is an oral multikinase inhibitor for patients with advanced RAI refractory DTC. However, the side effects and drug resistance of sorafenib suggest us to develop novel drugs and strategies for the therapy of thyroid carcinoma. In this study, we firstly found that patients with sorafenib resistance showed no significant change in rapidly accelerated fibrosarcoma and VEGFR expression levels compared with sorafenib sensitive patients. Moreover, a further miRNAs screen by qRT‐PCR indicated that miR‐124‐3p and miR‐506‐3p (miR‐124/506) were remarkably reduced in sorafenib insensitive patients. With a bioinformatics prediction and functional assay validation, we revealed that enhancer of zeste homolog 2 (EZH2) was the direct target for miR‐124/506. Interestingly, we finally proved that the sorafenib resistant cells regained sensitivity for sorafenib by EZH2 intervention with miR‐124/506 overexpression or EZH2 inhibitor treatment in vitro and in vivo, which will lead to the decreased tri‐methylation at lysine 27 of histone H3 (H3K27me3) and increased acetylated lysine 27 of histone H3 (H3K27ac) levels. Therefore, we conclude that the suppression of EZH2 represents a potential target for thyroid carcinoma therapy.

Extracellular Vesicles from Thyroid Carcinoma: The New Frontier of Liquid Biopsy

The diagnostic approach to thyroid cancer is one of the most challenging issues in oncology of the endocrine system because of its high incidence (3.8% of all new cancer cases in the US) and the difficulty to distinguish benign from malignant non-functional thyroid nodules and establish the cervical lymph node involvement during staging. Routine diagnosis of thyroid nodules usually relies on a fine-needle aspirate biopsy, which is invasive and often inaccurate. Therefore, there is an urgent need to identify novel, accurate, and non-invasive diagnostic procedures. Liquid biopsy, as a non-invasive approach for the detection of diagnostic biomarkers for early tumor diagnosis, prognosis, and disease monitoring, may be of particular benefit in this context. Extracellular vesicles (EVs) are a consistent source of tumor-derived RNA due to their prevalence in circulating bodily fluids, the well-established isolation protocols, and the fact that RNA in phospholipid bilayer-enclosed vesicles is protected from blood-borne RNases. Recent results in other types of cancer, including our recent study on plasma EVs from glioblastoma patients suggest that information derived from analysis of EVs from peripheral blood plasma can be integrated in the routine diagnostic tumor approach. In this review, we will examine the diagnostic and prognostic potential of liquid biopsy to detect tumor-derived nucleic acids in circulating EVs from patients with thyroid carcinoma.