BRAF-Activated Long Noncoding RNA Modulates Papillary Thyroid Carcinoma Cell Proliferation through Regulating Thyroid Stimulating Hormone Receptor

LncRNA PFAR facilitates the proliferation and migration of papillary thyroid carcinoma by competitively binding to miR-15a

Papillary thyroid carcinoma (PTC) is type of aggressive tumor, with a markedly declined survival rate when distant metastasis occurs. It is of great significance to develop potential biomarkers to evaluate the progression of PTC. LncRNAs are recently widely claimed with biomarker value in malignant tumors. Herein, the role of LncRNA PFAR in PTC was investigated to explore potential prognostic marker for PTC. Compared to NTHY-ORI 3-1 cells, LncRNA PFAR was found markedly upregulated in PTC cell lines. In LncRNA PFAR knockdown TPC-1 cells, markedly declined cell viability, increased apoptotic rate, enhancive number of migrated cells, and elevated migration distance were observed, accompanied by a suppressed activity of the RET/AKT/mTOR signaling. In LncRNA PFAR overexpressed BCPAP cells, signally increased cell viability, declined apoptotic rate, reduced number of migrated cells, decreased migration distance, and increased tumor volume and tumor weight in nude mice xenograft model were observed, accompanied by an activation of the RET/AKT/mTOR signaling. The binding site between LncRNA PFAR and miR-15a, as well as miR-15a and RET, was confirmed by the dual luciferase reporter assay. The FISH study revealed that LncRNA PFAR was mainly located in the cytoplasm. Furthermore, the impact of the siRNA targeting LncRNA PFAR against the growth and migration of PTC cells was abolished by the inhibitor of miR-15a or SC79, an activator of AKT/mTOR signaling. Collectively, LncRNA PFAR facilitated the proliferation and migration of PTC cells by mediating the miR-15a/RET axis.

YTHDC2 Retards Cell Proliferation and Triggers Apoptosis in Papillary Thyroid Cancer by Regulating CYLD-Mediated Inactivation of Akt Signaling

N6-Methyladenosine (m6A) mRNA methylation modification is regarded as an important mechanism involved in diverse physiological processes. YT521-B homology (YTH) domain family members are associated with the tumorigenesis of several cancers. However, the role of YTHDC2 in papillary thyroid cancer (PTC) progression remains unknown. Results showed that YTHDC1, YTHDF1, YTHDF2, and YTHDF3 showed no observable difference in thyroid cancer samples. YTHDC2 was significantly downregulated in thyroid cancer samples and cells. YTHDC2 inhibited cell proliferation in PTC cells. YTHDC2 elicited apoptosis in PTC cells, as demonstrated by the elevated expression of pro-apoptotic factors cl-caspase-3/caspase-3 and Bcl-2-associated (Bax), and the reduced anti-apoptotic B cell lymphoma-2 (Bcl-2) expression. There was a positive correlation between YTHDC2 and cylindromatosis (CYLD) expression based on GEPIA database. YTHDC2 increased CYLD expression in PTC cells. CYLD knockdown abolished the effects of YTHDC2 on PTC cell proliferation and apoptosis. Additionally, YTHDC2 inactivated the protein kinase B (Akt) pathway by increasing CYLD in PTC cells. Overall, YTHDC2 inhibited cell proliferation and induced apoptosis in PTC cells by regulating CYLD-mediated inactivation of Akt pathway.

Advances and challenges in thyroid cancer: The interplay of genetic modulators, targeted therapies, and AI-driven approaches

Thyroid cancer continues to exhibit a rising incidence globally, predominantly affecting women. Despite stable mortality rates, the unique characteristics of thyroid carcinoma warrant a distinct approach. Differentiated thyroid cancer, comprising most cases, is effectively managed through standard treatments such as thyroidectomy and radioiodine therapy. However, rarer variants, including anaplastic thyroid carcinoma, necessitate specialized interventions, often employing targeted therapies. Although these drugs focus on symptom management, they are not curative. This review delves into the fundamental modulators of thyroid cancers, encompassing genetic, epigenetic, and non-coding RNA factors while exploring their intricate interplay and influence. Epigenetic modifications directly affect the expression of causal genes, while long non-coding RNAs impact the function and expression of micro-RNAs, culminating in tumorigenesis. Additionally, this article provides a concise overview of the advantages and disadvantages associated with pharmacological and non-pharmacological therapeutic interventions in thyroid cancer. Furthermore, with technological advancements, integrating modern software and computing into healthcare and medical practices has become increasingly prevalent. Artificial intelligence and machine learning techniques hold the potential to predict treatment outcomes, analyze data, and develop personalized therapeutic approaches catering to patient specificity. In thyroid cancer, cutting-edge machine learning and deep learning technologies analyze factors such as ultrasonography results for tumor textures and biopsy samples from fine needle aspirations, paving the way for a more accurate and effective therapeutic landscape in the near future.

A review on the biological roles of LncRNA PTCSC3 in cancerous and non-cancerous disorders

Long non-coding RNA papillary thyroid carcinoma susceptibility candidate 3 (LncRNA PTCSC3) is located on human chromosome 14q13.3. PTCSC3 functions as a tumor suppressor lncRNA to regulate essential cellular processes such as apoptosis, cell proliferation, migration, invasion, angiogenesis, and epithelial-to-mesenchymal transition. PTCSC3 is also involved in the regulation of the Wnt/β-catenin signaling pathway, aerobic glycolysis, and p53 pathways. Downregulation of PTCSC3 has been associated with an increased risk of many tumors such as thyroid, gastric, laryngeal, breast, cervical, oral, lung, and glioma cancers. In addition, dysregulation of PTCSC3 has been reported in non-cancerous disorders notably osteoporosis and periodontitis. However, a number of single nucleotide polymorphisms at PTCSC3 have been linked to a higher risk of human diseases. This literature review summarizes the diagnostic, prognostic, and the clinical value of abnormal expression of PTCSC3 in cancerous and non-cancerous disorders and comprehensively analyzes potential molecular regulatory mechanism related to PTCSC3, which is expected to provide clear guidance for future PTCSC3 research.

Overexpression of ST7-AS1 Enhances Apoptosis and Inhibits Proliferation of Papillary Thyroid Carcinoma Cells Via microRNA-181b-5p-Dependent Inhibition Tripartite Motif Containing 3

Long non-coding RNAs (lncRNAs) are of great significance in the pathogenesis and progression of papillary thyroid carcinoma (PTC). LncRNA tumorigenicity 7 antisense RNA 1 (ST7-AS1) is a newly identified lncRNA serving as an oncogene or tumor suppressor in different tumors; however, the role of ST7-AS1 in PTC remains completely unknown. In this study, ST7-AS1 was mainly distributed in the cytoplasm of PTC cells and presented reduced expression in THCA tumors and PTC cell lines. Functional experiments revealed that overexpressed ST7-AS1 inhibited the viability and proliferation of PTC cells, whereas accelerated the apoptosis of PTC cells. The expression of miR-181b-5p was upregulated and it bound with ST7-AS1 in PTC cells. Moreover, TRIM3 exhibited downregulated expression level in PTC cells and ST7-AS1 elevated TRIM3 expression via harboring miR-181b-5p. Rescue experiments illuminated that knockdown of TRIM3 reversed ST7-AS1 overexpression-induced promotion on PTC cell proliferation and suppression on PTC cell apoptosis. Overall, overexpression of ST7-AS1 enhances apoptosis and represses proliferation of PTC cells via targeting the miR-181b-5p/TRIM3 axis, which may help broaden the horizon and establish the foundation to develop therapeutic strategies for PTC in the future.

Knockdown of KRAB domain-associated protein 1 suppresses the proliferation, migration and invasion of thyroid cancer cells by regulating P68/DEAD box protein 5

KRAB domain-associated protein 1 (KAP-1) has been reported to be an oncogene in diverse tumors. KAP-1 was found to have abundant existence in malignant thyroid tissues, but its role in thyroid cancer hasn’t been elucidated clearly. This study was carried out to explore the role of KAP-1 in thyroid cancer, and to clarify its molecular mechanism. The expressions of KAP-1 and P68/DEAD box protein 5 (DDX5) were assessed under the help of qRT-PCR and western blot. Then, we downregulated KAP-1 or upregulated DDX5 by cell transfection in TPC-1 cells. A series of cellular experiments on proliferation, apoptosis, migration and invasion were conducted with CCK-8, EdU, TUNEL, wound-healing and Transwell assays. Besides, the relationship between KAP-1 and DDX5 was verified by co-immunoprecipitation (Co-IP). The results showed that both of KAP-1 and DDX5 were upregulated in thyroid cancer cells. Loss-of-function experiments revealed that KAP-1 knockdown imparted suppressive effects on cell proliferation, migration and invasion, but promoted cell apoptosis. Additionally, KAP-1 was demonstrated to interact with DDX5 and positively regulate DDX5 expression. The following rescued experiments exhibited that the inhibitory effects of KAP-1 knockdown on cellular activities of thyroid cancer and Wnt/β-catenin signaling were also partly reversed by DDX5 overexpression. Moreover, activation of Wnt/β-catenin signaling retarded the anti-tumor activity of KAP-1 knockdown. In conclusion, the data in this study disclosed that KAP-1 silence helped to repress the cell proliferation, migration and invasion by degrading DDK5, so as to hinder the development of thyroid cancer.

Identification of prognostic signature with seven LncRNAs for papillary thyroid carcinoma

PURPOSE

With the increasing incidence of thyroid cancer (TC), the prognostic risk assessment of thyroid cancer has been becoming more and more important. The aim of this study was to screen TC-related biomarkers and identify key multi-long non coding RNA (lncRNA) signature for prognostic risk assessment of papillary TC.

MATERIAL AND METHODS

The lncRNAs differentially expressed between TC tissue and adjacent normal tissue was identified by R language. Bioinformatics analysis was applied to screen the lncRNAs significantly associated with prognosis in TC patients and build the multi-lncRNA signature. The lncRNAs were annotated by co-expression and enrichment analysis to demonstrate the underlying mechanism of their effect on prognosis.

RESULTS

285 up-regulated and 174 down-regulated differently expressed lncRNAs were identified. Based on seven signature lncRNAs (AL591846.2, AC253536.3, AC004112.1, LINC00900, AC008555.1, TNRC6C-AS1, LINC01736) a prognostic risk assessment model was built. The model can segregate the patients into the high-risk and low-risk groups (P value <0.0001, CI: 0.02∼0.14). ROC analysis revealed that the area under the curve reached 0.86, indicating that this model had an excellent sensitivity and specificity. Also, the model could act as an independent prognostic indication (HR ​= ​2.90, P value ​= ​0.0094 with multivariate analysis). Annotation results further supported and enriched our understanding of the seven signature lncRNAs. Importantly, expression levels of three of the seven lncRNAs were confirmed in Gene Expression Omnibus (GEO) data.

CONCLUSIONS

This study has provided a promising method for the prognostic risk assessment in patients with TC.

Long Non-Coding RNAs Profiling Using Microarray in Papillary Thyroid Carcinoma

Long non-coding RNAs (lncRNAs) have been implicated in various cancers, including papillary thyroid carcinomas (PTCs). Genome-wide analysis (GWAS) of lncRNAs expression in PTC samples exhibited up and down regulation of lncRNAs, thus, acting as tumor promoting oncogenes or tumor suppressors in the pathogenesis of PTC by interacting with target genes. For example, lncRNAs such as HOTAIR, NEAT1, MALAT1, FAL1, HOXD-AS1, etc. are overexpressed in PTC in comparison to that of non-cancerous thyroid tissues, which stimulate the pathogenesis of PTC. On the other hand, lncRNAs such as MEG3, CASC2, PANDAR, LINC00271, NAMA, PTCSC3, etc. are down regulated in PTC tissues when compared to that of non-cancerous thyroid samples, suppressing formation of PTC. Also, several lncRNAs such as BANCR acts as oncogenic or tumor suppressor in PTC formation depending on which they are interacting with. In addition, lncRNAs expression in patients with PTC associated with clinicopathological parameters such as distance metastasis, lymph node metastasis, tumor size, pathological stage, and response to therapy. Thus, lncRNAs profiles could have the potential to be used as prognostic or predictive biomarker in patients with PTC. Therefore, we describe the microarray method to examine lncRNAs expression in PTC tissue samples, which could facilitate better management of patients with PTC. Furthermore, this method could be fabricated to examine lncRNAs expression in other biological and/or clinical samples.

LINC01087 Promotes the Proliferation, Migration, and Invasion of Thyroid Cancer Cells by Upregulating PPM1E

This study is aimed at investigating the effect and mechanism of LINC01087 on the malignant evolution of thyroid cancer cells. The expression levels of LINC01087, miR-135a-5p, and PPM1E in thyroid carcinoma tissues were detected by QRT-PCR. Cell viability was detected using the CCK-8 method. Transwell assay was used to assess the ability of cells to invade. The targeting relationship between LINC01087 and miR-135a-5p was detected by dual luciferase reporting assay. In comparison with normal thyroid tissues and cells, the expression level of LINC01087 in thyroid cancer tissues and TPC-1 and K1 cells increased, and the expression level of miR-135a-5p in thyroid cancer tissues and TPC-1 and K1 cells decreased. LINC01087 knockdown and the high expression of miR-143-3p inhibited the proliferation, invasion, and EMT processes of TPC-1 and K1 in thyroid cancer cells. LINC01087 negatively targeted miR-135a-5p. Has-miR-135a-5p inhibited the malignant evolution and EMT of thyroid cancer by targeting PPM1E. The PPM1E overexpression can reverse the inhibitory effect of LINC01087 gene knockdown on the proliferation, migration, and invasion of thyroid cancer cells. LINC01087 can promote the proliferation and apoptosis of thyroid cancer cells, and its mechanism may be related to the miR-135a-5p/PPM1E axis.

Epigenetic modification and BRAF gene mutation in thyroid carcinoma

Thyroid cancer remains the most prevailing endocrine malignancy, and a progressively increasing incidence rate has been observed in recent years, with 95% of thyroid cancer represented by differentiated thyroid carcinomas. The genetics and epigenetics of thyroid cancer are gradually increasing, and gene mutations and methylation changes play an important roles in its occurrence and development. Although the role of RAS and BRAF mutations in thyroid cancer have been partially clarified,but the pathogenesis and molecular mechanisms of thyroid cancer remain to be elucidated. Epigenetic modification refer to genetic modification that does not change the DNA sequence of a gene but causes heritable phenotypic changes in its expression. Epigenetic modification mainly includes four aspects: DNA methylation, chromatin remodelling, noncoding RNA regulation, and histone modification. This article reviews the importance of thyroid cancer epigenetic modification and BRAF gene mutation in the treatment of thyroid cancer.

LncRNA-MIAT promotes thyroid cancer progression and function as ceRNA to target EZH2 by sponging miR-150-5p

While long noncoding RNAs (lncRNAs) have been reported to play an important role in human cancer types, they remain poorly understood in papillary thyroid carcinoma (PTC). The aim of this study was to use genome-wide expression profiling to identify lncRNAs acting as competing endogenous RNAs (ceRNAs) in PTC. We constructed a ceRNA network based on our lncRNA microarray data and validated the correlation between myocardial infarction-associated transcript lncRNA (MIAT), miRNA-150-5p, and EZH2 in vitro and in vivo. We found 15 lncRNAs, 28 miRNAs, and hundreds of mRNAs involved in this ceRNA network. Splendid positive correlations were found between the MIAT and EZH2 expression in types of cancer in TCGA data. Besides, significant differences in MIAT/EZH2 expression were found among various clinicopathological features. Gain- and loss-of-function experiments revealed that MIAT inhibited cell proliferation and migration in vitro. Moreover, EZH2 was identified as a direct downstream target of miR-150-5p in PTC cells. Restoration of EZH2 expression partially abolished the biological effects of miR-150-5p. Furthermore, overexpression of MIAT was inversely correlated with miR-150-5p expression. Knockdown of MIAT produced significant behavioral alter maybe partly due to the function of the MIAT-150-5p-EZH2 network. Our findings suggest MIAT may inhibit EZH2 expression and promote PTC cell invasion via the miR-150/EZH2 pathway. Therefore, MIAT may serve as a valuable prognostic biomarker and therapeutic target for PTC.

LncRNA-MIAT promotes thyroid cancer progression and function as ceRNA to target EZH2 by sponging miR-150-5p

While long noncoding RNAs (lncRNAs) have been reported to play an important role in human cancer types, they remain poorly understood in papillary thyroid carcinoma (PTC). The aim of this study was to use genome-wide expression profiling to identify lncRNAs acting as competing endogenous RNAs (ceRNAs) in PTC. We constructed a ceRNA network based on our lncRNA microarray data and validated the correlation between myocardial infarction-associated transcript lncRNA (MIAT), miRNA-150-5p, and EZH2 in vitro and in vivo. We found 15 lncRNAs, 28 miRNAs, and hundreds of mRNAs involved in this ceRNA network. Splendid positive correlations were found between the MIAT and EZH2 expression in types of cancer in TCGA data. Besides, significant differences in MIAT/EZH2 expression were found among various clinicopathological features. Gain- and loss-of-function experiments revealed that MIAT inhibited cell proliferation and migration in vitro. Moreover, EZH2 was identified as a direct downstream target of miR-150-5p in PTC cells. Restoration of EZH2 expression partially abolished the biological effects of miR-150-5p. Furthermore, overexpression of MIAT was inversely correlated with miR-150-5p expression. Knockdown of MIAT produced significant behavioral alter maybe partly due to the function of the MIAT-150-5p-EZH2 network. Our findings suggest MIAT may inhibit EZH2 expression and promote PTC cell invasion via the miR-150/EZH2 pathway. Therefore, MIAT may serve as a valuable prognostic biomarker and therapeutic target for PTC.

Role of lncRNA BANCR in Human Cancers: An Updated Review

Being located in a gene desert region on 9q21.11-q21.12, BRAF-activated non-protein coding RNA (BANCR) is an lncRNA with 693 bp length. It has been discovered in 2012 in a research aimed at assessment of gene expression in the melanocytes in association with BRAF mutation. Increasing numbers of studies have determined its importance in the tumorigenesis through affecting cell proliferation, migration, invasion, apoptosis, and epithelial to mesenchymal transition. BANCR exerts its effects via modulating some tumor-related signaling pathways particularly MAPK and other regulatory mechanisms such as sponging miRNAs. BANCR has been up-regulated in endometrial, gastric, breast, melanoma, and retinoblastoma. Conversely, it has been down-regulated in some other cancers such as those originated from lung, bladder, and renal tissues. In some cancer types such as colorectal cancer, hepatocellular carcinoma and papillary thyroid carcinoma, there is no agreement about BANCR expression, necessitating the importance of additional functional studies in these tissues. In the present manuscript, we review the investigations related to BANCR expression changes in cancerous cell lines, clinical samples, and animal models of cancer. We also discuss the outcome of its deregulation in cancer progression, prognosis, and the underlying mechanisms of these observations.

Long noncoding RNA landscapes specific to benign and malignant thyroid neoplasms of distinct histological subtypes

The main types of thyroid neoplasms, follicular adenoma (FA), follicular thyroid carcinoma (FTC), classical and follicular variants of papillary carcinoma (clPTC and fvPTC), and anaplastic thyroid carcinoma (ATC), differ in prognosis, progression rate and metastatic behaviour. Specific patterns of lncRNAs involved in the development of clinical and morphological features can be presumed. LncRNA landscapes within distinct benign and malignant histological variants of thyroid neoplasms were not investigated. The aim of the study was to discover long noncoding RNA landscapes common and specific to major benign and malignant histological subtypes of thyroid neoplasms. LncRNA expression in FA, FTC, fvPTC, clPTC and ATC was analysed with comprehensive microarray and RNA-Seq datasets. Putative biological functions were evaluated via enrichment analysis of coexpressed coding genes. In the results, lncRNAs common and specific to FTC, clPTC, fvPTC, and ATC were identified. The discovered lncRNAs are putatively involved in L1CAM interactions, namely, pre-mRNA processing (lncRNAs specific to FTC); PCP/CE and WNT pathways (lncRNAs specific to fvPTC); extracellular matrix organization (lncRNAs specific to clPTC); and the cell cycle (lncRNAs specific to ATC). Known oncogenic and suppressor lncRNAs (RMST, CRNDE, SLC26A4-AS1, NR2F1-AS1, and LINC00511) were aberrantly expressed in thyroid carcinomas. These findings enhance the understanding of lncRNAs in the development of subtype-specific features in thyroid cancer.

Long noncoding RNA ILF3-AS1 aggravates papillary thyroid carcinoma progression via regulating the miR-4306/PLAGL2 axis

BACKGROUND

It have been proven that long non-coding RNAs (lncRNAs) serve as regulators in carcinogenesis. Interleukin enhancer binding factor 3 antisense RNA 1 (ILF3-AS1) has been illuminated as a prognostic factor in some cancers. Nevertheless, its expression pattern and possible functions in papillary thyroid carcinoma (PTC) have not been studied.

METHODS

The expression of ILF3-AS1 was measured by RT-qPCR and ISH. Colony formation assay and EdU assay were used to probe cell proliferation. TUNEL assay was used for analysis of cell apoptosis. Immunofluorescence and western blot were conducted to evaluate the expression change of E-cadherin and N-cadherin. The RNA interaction was demonstrated by mechanism experiments, including pull down assay and dual luciferase reporter assay.

RESULTS

ILF3-AS1 expression was evidently upregulated in PTC cell lines. ILF3-AS1 knockdown restrained the proliferation, migration and invasion of PTC cells. Mechanical investigation revealed that miR-4306 could interact with ILF3-AS1. PLAGL2 was a downstream target of miR-4306. The effects of ILF3-AS1 knockdown on the cellular processes were abrogated by miR-4306 downregulation or pleiomorphic adenoma gene-like 2 (PLAGL2) overexpression.

CONCLUSION

ILF3-AS1 plays tumor-promoting role in PTC via targeting miR-4306/PLAGL2 axis.

The NEAT1_2/miR-491 Axis Modulates Papillary Thyroid Cancer Invasion and Metastasis Through TGM2/NFκb/FN1 Signaling

NEAT1 (nuclear paraspeckle assembly transcript 1) is an oncogenic long non-coding RNA (lncRNA) that facilitates tumorigenesis in multiple cancers. In papillary thyroid cancer (PTC), the molecular mechanism by which NEAT1 affects invasion and metastasis remains elusive. RNA sequencing was used to discover differentially expressed NEAT1_2 downstream genes. Protein and RNA expression analyses and immunohistochemistry detected the expression of NEAT1_2, Transglutaminase 2 (TGM2), and microRNA-491 (miR-491) among PTC and non-cancerous tissues. Transwell and wound healing assays, and a mouse model of lung metastasis were used for further functional analyses. Bioinformatics was performed to predict miRNAs binding to both NEAT1_2 and TGM2. Rescue experiments and dual-luciferase reporter assays were performed. In PTC tissues, NEAT1_2 expression was markedly increased and regulated TGM2 expression. TGM2 was overexpressed in PTC, correlating positively with exthyroidal extension and lymph node metastasis. TGM2 knockdown significantly inhibited invasion and metastasis. NEAT1_2 sponged miR-491, acting as a competing endogenous RNA to regulate TGM2 expression. Fibronectin 1 (FN1) was predicted as a TGM2 target. TGM2 could transcriptionally activate FN1 by promoting nuclear factor kappa B (NFκb) p65 nuclear translocation, ultimately promoting PTC invasion/metastasis. These findings identify that NEAT1_2 sponges miR-491 to regulate TGM2 expression. TGM2 activates FN1 via NFκb to promote PTC invasion and metastasis.

Chaperone-mediated Autophagy Governs Progression of Papillary Thyroid Carcinoma via PPARγ-SDF1/CXCR4 Signaling

CONTEXT

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy. Chaperone-mediated autophagy (CMA), 1 type of autophagy, is thought to promote or suppress cancer development in different cancer types. However, the effect of CMA on PTC development and the underlying mechanisms remain unknown.

OBJECTIVE

To determine whether CMA plays implied critical roles in the development of PTC.

DESIGN

We investigated the association between CMA and PTC development in PTC tissues and normal thyroid tissues by detecting the key protein of CMA, lysosome-associated membrane protein type 2A (LAMP2A), using quantitative polymerase chain reaction (PCR) and immunohistochemistry, which were further validated in the TGCA dataset. The effect of CMA on PTC development was studied by cell proliferation, migration, and apoptosis assays. The underlying mechanisms of peroxisome proliferator-activated receptor γ (PPARγ)-stromal cell-derived factor 1 (SDF1)/ C-X-C motif chemokine receptor 4 (CXCR4) signaling were clarified by western blotting, quantitative PCR, and rescue experiments. Knockdown and tamoxifen were used to analyze the effect of estrogen receptor (ER) α on CMA.

RESULTS

Our study confirmed that CMA, indicated by LAMP2A expression, was significantly increased in PTC tumor tissues and cell lines, and was associated with tumor size and lymph node metastasis of patients. Higher CMA in PTC promoted tumor cell proliferation and migration, thereby promoting tumor growth and metastasis. These effects of CMA on PTC were exerted by decreasing PPARγ protein expression to enhance SDF1 and CXCR4 expression. Furthermore, CMA was found positively regulated by ERα signaling in PTC.

CONCLUSION

Our investigation identified CMA regulated by ERα promoting PTC tumor progression that enhanced tumor cell proliferation and migration by targeting PPARγ-SDF1/CXCR4 signaling, representing a potential target for treatment of PTC.

Overexpression of novel long intergenic non‑coding RNA LINC02454 is associated with a poor prognosis in papillary thyroid cancer

It has been revealed from microarray data analysis that long intergenic non-coding RNA 02454 (LINC02454) is highly expressed in papillary thyroid cancer (PTC). The aim of the present study was to explore the potential role of LINC02454 in the tumorigenesis of PTC. The mRNA expression levels of LINC02454 were assessed using data from The Cancer Genome Atlas (TCGA) and the GSE66783 cohort in thyroid cancer, and were validated using reverse transcription-quantitative PCR in 104 patients with PTC recruited in the present study. The association between the LINC02454 mRNA expression levels and the clinicopathological features of the 104 patients with PTC were also analyzed. Functional enrichment analyses were conducted on the differentially expressed genes in the high and low LINC02454 expression groups that were identified from the TCGA cohort. RNA interference, using short interfering (si)RNA against LINC02454, was used to investigate the role of LINC02454 in the biological functions of PTC cells in vitro. The expression level of LINC02454 was significantly increased in PTC tissues (P=0.0011) and was significantly associated with a larger tumor size, T stage, an advanced TNM stage and an increased lymph node metastasis (P<0.05), which was consistent with that in the TCGA and GSE66783 cohort. High expression levels of LINC02454 were observed in patients with PTC that also had BRAF mutations (P<0.001), and were significantly associated with a poorer disease-free survival in the TCGA cohort (P<0.05). Functional enrichment analysis indicated that LINC02454-related genes were significantly enriched in Gene Ontology terms, such as ‘positive regulation of cell proliferation’, ‘positive regulation of cell division’ and ‘cell adhesion’, and the following Kyoto Encyclopedia of Genes and Genomes pathways: ‘Pathways in cancer’ ‘proteoglycans in cancer’ and ‘ECM-receptor interaction’. In vitro, the knockdown of LINC02454 markedly arrested the cells in the G₀/G₁ phase of the cell cycle, and also led to an overall increase in apoptosis, as well as to an unexpected decrease in cell proliferation. LINC02454 may thus potentially function as an oncogene, which inhibits the apoptosis and enhances proliferation of PTC cells. Thus, as suggested by the findings of the present study, LINC02454 may be used as a diagnostic and prognostic biomarker for PTC in the future.

Elevated BANCR expression levels have different effects on papillary thyroid carcinoma progression depending on the presence of the BRAFV600E mutation

INTRODUCTION

The role of BRAF-activated non-protein coding RNA (BANCR) in papillary thyroid carcinoma (PTC) is controversial, its clinical significance is unclear and no study has correlated the presence of the BRAFV600E mutation in PTC with BANCR expression.

METHODS

BANCR levels in PTC and matched nonmalignant thyroid epithelial tissues from 85 patients were determined using quantitative RT-PCR. BRAFV600E was detected by mutant allele-specific PCR amplification. The results were correlated with clinicopathological characteristics of the patients.

RESULTS

The presence of BRAFV600E associates with lower relative BANCR expression (RBE) in PTC (p = 0.008). RBE is down-regulated in BRAFV600E positive PTC, while it is unchanged or up-regulated in BRAFV600E negative PTC compared to the levels in paired nonmalignant tissue (p = 0.001). At the cut-off of 31.3%, sensitivity of fold change of BANCR for the presence of BRAFV600E is 68.0% and specificity is 67.2%. In BRAFV600E positive PTC up-regulated BANCR predicts lymph node metastasis (p = 0.001), while in BRAFV600E negative PTCs high RBE predicts thyroid capsule invasion (p = 0.028).

CONCLUSIONS

Depending on the presence of BRAFV600E, elevated BANCR levels demonstrated different effects on lymphatic spreading and local PTC invasion. Therefore, BANCR could be a useful prognostic biomarker in risk stratification of PTC patients.

The Role of Long Non-Coding RNAs in Thyroid Cancer

Thyroid cancer, the most common endocrine malignancy, has become the most commonly diagnosed malignant solid tumor. Moreover, some cases have poor prognosis, and the survival period is only 3-5 months. Long noncoding RNAs (lncRNAs) are a group of functional RNA molecules more than 200 nucleotides in length that lack the ability to encode protein but participate in all aspects of gene regulation. Functionally, many lncRNAs play essential roles in epigenetic regulation at transcriptional and post-transcriptional levels via various molecular mechanisms. Recent studies have discovered important roles for lncRNAs during the complex process of carcinogenesis in thyroid cancer. In this review, we focus on lncRNAs dysregulated in thyroid cancer and summarize recently reported associations between lncRNAs and thyroid cancer in order to demonstrate the significant value of lncRNAs in diagnosis and treatment.

LncRNAs as Potential Therapeutic Targets in Thyroid Cancer

Thyroid cancer (TC) is the most common cancer of endocrine system. TC can be subdivided into 4 different entities, papillary, follicular, medullary and anaplastic thyroid cancer. Among them, anaplastic thyroid cancer has the poorest prognosis. Exploring new therapeutic approach may entail favorable prediction as well as increasing overall survival rate of patients. Long non-coding RNAs (lncRNAs), have vast implications in different cancer types. Although they are not transcribed into proteins, they can act as a harness in regulating a plethora of biological functions. They have been implicated in a decisive role in gene expression via modulation of both coding and non-coding RNAs. This article discuss the multi-facet role of lncRNA in thyroid cancer biology.

MicroRNA-384 Inhibits the Progression of Papillary Thyroid Cancer by Targeting PRKACB

Background

Growing evidence shows that dysregulation of miRNAs plays a significant role in papillary thyroid cancer (PTC) tumorigenesis and development. The abnormal expression of miR-384 has been acknowledged in the proliferation or metastasis of some cancers. However, the function and the underlying mechanism of miR-384 in PTC progression remain largely unknown.

Methods

Real-time PCR was conducted to detect miR-384 expression in 58 cases of PTC and their adjacent noncancerous tissues. MTT, soft agar assay Transwell assay, and wound-healing assay were carried out to explore the biological function of miR-384 in PTC cell lines of BCPAP and K1. Bioinformatics analysis, dual-luciferase reporter assay, western blot, and functional complementation analysis were conducted to explore the target gene of miR-384. Moreover, Spearman's correlation analysis was conducted to reveal the correlation between miR-384 and PRKACB mRNA in PTC.

Results

The expression of miR-384 decreased obviously in PTC, especially in the tumors with lymph node metastasis or larger tumor size. The ectopic upregulation of miR-384 significantly suppressed PTC progression, and the inhibition of miR-384 had the opposite effects. Moreover, PRKACB gene was confirmed as the target of miR-384.

Conclusion

The study suggests that miR-384 serves as a tumor suppressor in PTC progression by directly targeting the 3′-UTR of PRKACB gene.

LncRNAs SNHG12 and LINC00152 were associated with progression of patients with papillary thyroid carcinoma

Aim: To investigate the clinical roles of LINC00152 and SNHG12 in papillary thyroid carcinoma (PTC). Methods: LINC00152 and SNHG12 expression was sought and analysis in gene expression omnibus, The Cancer Genome Atlas and GEPIA datasets. Tumor and adjacent normal tissues were collected from 97 PTC and 44 benign thyroid nodules patients. The expression was evaluated by quantitative real-time polymerase chain reaction. The association between the expression level and clinicopathologic characteristics was analyzed by χ² test. Receiver operating characteristic curves were plotted to evaluate the diagnostic value. Results: The expression of SNHG12 and LINC00152 were significantly higher in PTC tissues than in adjacent normal tissues not only in gene expression omnibus database but the validated samples. More interesting, LINC00152 expression level was also significantly higher in PTC tissues than that in benign thyroid nodules. The upregulation of LINC00152 and SNHG12 was associated with the malignant progression of PTC. Receiver operating characteristic curve analysis also demonstrated that there was a good trend, which indicates that they may have certain diagnostic value. Conclusion: LINC00152 and SNHG12 might serve as serve as potential related molecules of PTC.

Influencers on Thyroid Cancer Onset: Molecular Genetic Basis

Thyroid cancer, a cancerous tumor or growth located within the thyroid gland, is the most common endocrine cancer. It is one of the few cancers whereby incidence rates have increased in recent years. It occurs in all age groups, from children through to seniors. Most studies are focused on dissecting its genetic basis, since our current knowledge of the genetic background of the different forms of thyroid cancer is far from complete, which poses a challenge for diagnosis and prognosis of the disease. In this review, we describe prevailing advances and update our understanding of the molecular genetics of thyroid cancer, focusing on the main genes related with the pathology, including the different noncoding RNAs associated with the disease.

The role of long non-coding RNAs in the pathogenesis of thyroid cancer

Long noncoding RNAs (lncRNAs) as prominent regulators of gene expression are involved in different layers of expression regulation. These transcripts participate in carcinogenesis of several human malignancies including thyroid cancer. Availability of high throughput techniques such as RNA sequencing and microarray has facilitated identification of lncRNAs whose dysregulation affect tumorigenesis process. Moreover, assessment of differentially expressed lncRNAs between resistant and sensitive cells has led to recognition of biomarkers for therapeutic response. One elucidated aspect of lncRNAs functions is their role in sponging miRNAs. Several miRNA-lncRNA-mRNA triplets have been recognized till now. Any of these triplets is a putative target of interfering with the evolution of cancer. In the current study, we have summarized recent data in the fields of biology of lncRNAs, their role in thyroid cancer and their potential as biomarker or treatment target.

LINC01410/miR-3619-5p/FOXM1 Feedback Loop Regulates Papillary Thyroid Carcinoma Cell Proliferation and Apoptosis

Backgrounds: Thyroid cancer (TC) is a prevalent type of cancer in endocrine system. Past decades have seen the rising mortality and morbidity of TC. Long noncoding RNAs are renowned modulators of cancer onset and progression as validated by mounting studies. Long intergenic non-protein coding RNA 1410 (LINC01410) has been suggested as tumor-promoting gene in colon cancer and gastric cancer, but its role in TC is elusive. This study investigated the impact and mechanism of LINC01410 in TC. Materials and Methods: RT-qPCR and western blot were used to detect gene expression levels. Cell counting kit-8 (CCK-8) and ethynyl-2'-deoxyuridine (EdU) assays were used to determine proliferation. Caspase-3 activity assay was used to examine apoptosis. Intermolecular interaction was investigated by luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay. Results: We confirmed the elevation of LINC01410 expression in TC cells. Loss-of-function experiments indicated that LINC01410 knockdown suppressed proliferation and facilitated apoptosis in TC. Mechanism research illustrated that LINC01410 positively regulated forkhead box M1 (FOXM1) expression through targeting miR-3619-5p, and that FOXM1 in turn transcriptionally activated LINC01410. Rescue experiments validated that LINC01410 regulated TC proliferation and apoptosis through miR-3619-5p/FOXM1. Conclusions: This study demonstrated that LINC01410/miR-3619-5p/FOXM1 positive feedback loop regulated cell proliferation and apoptosis in TC, shedding a light on the molecular target identification and promising treatment improvement in TC.

Long noncoding RNAs in thyroid cancer

PURPOSE OF REVIEW

Our understanding of the molecular pathology events involved in thyroid cancer initiation and progression and its subtypes has markedly improved as a result of multiomic studies. Recently, long noncoding RNA (lncRNA) have been shown to have a role in cancer initiation and progression and have also been studied in thyroid cancer.

RECENT FINDINGS

lncRNA are dysregulated in thyroid cancer. lncRNA have tumor suppressive and oncogenic function in thyroid cancer cells and play a role in some of the established genetic drivers of thyroid cancer initiation and progression. Lastly, some lncRNA are associated with clinicopathologic features of thyroid cancer and circulating blood lncRNA could potentially detect the presence of thyroid cancer.

SUMMARY

We highlight the possible clinical utility of analyzing lncRNAs as biomarkers for thyroid cancer diagnosis and prognosis and their association with common genetic changes associated with thyroid cancer.

Long non-coding RNA NR2F1-AS1 promoted proliferation and migration yet suppressed apoptosis of thyroid cancer cells through regulating miRNA-338-3p/CCND1 axis

Thyroid cancer (TC) is a prevalent endocrine malignant cancer whose pathogenic mechanism remains unclear. The aim of the study was to investigate the roles of long non‐coding RNA (lncRNA) NR2F1‐AS1/miRNA‐338‐3P/CCND1 axis in TC progression. Differentially expressed lncRNAs and mRNAs in TC tissues were screened out and visualized by R program. Relative expression of NR2F1‐AS1, miRNA‐338‐3p and cyclin D1 (CCND1) was determined by quantitative real time polymerase chain reaction. In addition, Western blot analysis was adopted for evaluation of protein expression of CCND1. Targeted relationships between NR2F1‐AS1 and miRNA‐338‐3p, as well as miRNA‐338‐3p and CCND1 were predicted using bioinformatics analysis and validated by dual‐luciferase reporter gene assay. Besides, tumour xenograft assay was adopted for verification of the role of NR2F1‐AS1 in TC in vivo. NR2F1‐AS1 and CCND1 were overexpressed, whereas miRNA‐338‐3p was down‐regulated in TC tissues and cell lines. Down‐regulation of NR2F1‐AS1 and CCND1 suppressed proliferation and migration of TC cells yet greatly enhanced cell apoptotic rate. Silence of NR2F1‐AS1 significantly suppressed TC tumorigenesis in vivo. NR2F1‐AS1 sponged miRNA‐338‐3p to up‐regulate CCND1 expression to promote TC progression. Our study demonstrated that up‐regulation of NR2F1‐AS1 accelerated TC progression through regulating miRNA‐338‐3P/CCND1 axis.

Long non-coding RNA H19 knockdown inhibits the cell viability and promotes apoptosis of thyroid cancer cells through regulating the PI3K/AKT pathway

Certain long non-coding (lnc)RNAs have been reported to serve important roles in the genesis and progression of thyroid cancer (TC). Recent studies have demonstrated that the expression of lncRNA H19 is upregulated in TC tissues; however, knowledge of the associated molecular mechanisms is limited. Therefore, the present study aimed to clarify the roles of H19 in TC. The mRNA expression of lncRNA H19 in TC tissues was determined using reverse transcription-quantitative polymerase chain reaction analysis, and the effects of H19 knockdown on cell viability and apoptosis in vitro were assessed using MTT and flow cytometric assays, respectively. Finally, the signaling pathways involved in the effects of H19 were examined. The results indicated that H19 was upregulated in TC tissues. Silencing of H19 inhibited the cell viability and promoted apoptosis of FTC-133 and TPC-1 TC cells, accompanied by an increased expression of B-cell lymphoma 2 (Bcl-2)-associated X protein and caspase 3, and repressed expression of Bcl-2. The results of western blot analysis suggested that the levels of phosphorylated phosphoinositide-3 kinase (PI3K) and phosphorylated AKT were attenuated by H19 silencing. These results suggest that lncRNA H19 exerts an oncogenic function in TC, in part through the PI3K/AKT pathway.

A novel lncRNA n384546 promotes thyroid papillary cancer progression and metastasis by acting as a competing endogenous RNA of miR-145-5p to regulate AKT3

Long noncoding RNAs (lncRNAs) are emerging as important regulators in the development of cancer cells. However, the role and mechanisms of most lncRNAs in papillary thyroid carcinoma (PTC) remain unknown. In this study, we investigated lncRNA expression profiles of PTC using RNA-seq in two groups of PTC tissues and adjacent normal tissues, and validated by real-time PCR analysis in another 53 pairs of tissues. We identified a novel lncRNA, n384546, which is highly expressed in PTC tissues and cell lines. n384546 expression was associated with clinicopathological features of PTC patients, such as tumor size, lymph node metastasis, and TNM stage. Functionally, knockdown of n384546 inhibited PTC cell proliferation, invasion, and migration both in vitro and in vivo. In addition, we identified miR-145-5p as a key miRNA target of n384546 using online bioinformatics tools. Anti-miR-145 could partially reverse the effects of n384546 knockdown. Furthermore, we found that n384546 could regulate the expression of AKT3 by sponging miR-145-5p, which was confirmed using an in vitro luciferase assay. In conclusion, we validated n384546 as a novel oncogenic lncRNA in PTC and determined that the n384546/miR-145-5p/AKT3 pathway contributes to PTC progression, which might be used as potential therapeutic targets for PTC patients.

Long noncoding RNA RP11-547D24.1 regulates proliferation and migration in papillary thyroid carcinoma: Identification and validation of a novel long noncoding RNA through integrated analysis of TCGA database

Long noncoding RNAs (lncRNAs) are known to be key regulators of numerous biological processes, and substantial evidence supports that abnormal lncRNA expression plays a significant role in tumorigenesis and tumor progression. However, the mechanism by which lncRNAs function in thyroid carcinoma are still unclear. To investigate the role of lncRNAs in the tumorigenesis of papillary thyroid carcinoma (PTC), we analyzed lncRNA data in The Cancer Genome Atlas RNA‐Seq database. A comparison of lncRNAs in cancerous thyroid tissues and normal tissues revealed hundreds of differentially expressed lncRNAs. Of 7589 lncRNAs identified in 561 thyroid cancer cases (503 cancerous tissues and 58 normal tissues), the expression levels of 144 were found to be aberrant (|log2 fold change| >2 and adjusted P < 0.05). The top 10 lncRNAs with the most significant differences were LINC01977, RP11‐363E7.4, RP3‐483K16.4, RP11‐547D24.1, RUNDC3A‐AS1, AC093609.1, CTD‐2008L17.2, HAGLROS, UNC5B‐AS1, and LINC01354. In addition, CTD‐2008L17.2, HAGLROS, AC093609.1, UNC5B‐AS1, and RUNDC3A‐AS1 were shown to play vital roles in determining the histological cancer type. Furthermore, RP11‐547D24.1 and UNC5B‐AS1 could distinguish patients with different stages of PTC. The lncRNA RP11‐547D24.1 was validated by loss‐of‐function assays, revealing that downregulation of this lncRNA regulates thyroid tumor cell proliferation and apoptosis, invasion, and migration. This study demonstrates the potential for using lncRNAs to interpret the pathogenesis and development of PTC.

LncRNA ENST00000539653 acts as an oncogenic factor via MAPK signalling in papillary thyroid cancer

Background

Papillary thyroid cancer (PTC) is the most frequent type of thyroid malignancy. In this study, we investigated the mechanisms whereby long non-coding RNAs (lncRNAs) are associated with PTC pathogenesis.

Methods

Microarray analysis was used to determine differentially expressed lncRNAs between paired PTC tissues and normal adjacent thyroid tissues. Quantitative RT-PCR was used for validation in 86 PTC cases. Small interfering RNA (siRNA) transfection assays were then performed to assess how a novel lncRNA affected key proliferation and cell death pathways in IHH4 PTC cells.

Results

We identified 1878 differentially expressed lncRNAs versus matched control samples (fold change ≥2.0, P < 0.05), of which 429 were upregulated and 1449 were downregulated. ENST00000539653.1 (ENS-653), one of the top hits in this microarray, was selected for further study. Higher ENS-653 expression was observed in PTC tissue samples versus adjacent normal tissues, and was associated with a larger tumor size and a more advanced clinical stage. In the Cancer Genome Atlas (TCGA) PTC cohort, higher ENS-653 expression was correlated with more frequent BRAF (V600E) mutation and poorer disease-free survival. Furthermore, ENS-653 downregulation reduced the proliferation of PTC cells and led to G1-S arrest, but had no impact on apoptosis. ENS-653 downregulation also inactivated ERK1/2 and ERK5, causing partial MAPK cascade suppression.

Conclusion

ENS-653 exhibits oncogenic properties in PTC, and could be a diagnostic and/or prognostic PTC biomarker, in addition to possibly being a future target for therapy.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5533-4) contains supplementary material, which is available to authorized users.

Molecular aberrations and signaling cascades implicated in the pathogenesis of anaplastic thyroid cancer

Anaplastic Thyroid Cancer (ATC) accounts for >40% thyroid cancer-related deaths and has a dismal prognosis. In the past decade, significant efforts have been made towards understanding the pathogenesis of this disease and developing novel therapeutics. Unfortunately, effective treatment is still lacking and a more thorough understanding of ATC pathogenesis may provide new opportunities to improve ATC therapeutics. This review provides insights into ATC clinical presentation and pathology, and the putative role of genetic aberrations and alterations in molecular signaling pathways in ATC pathogenesis. We reviewed prevalent mutations, chromosomal abnormalities and fusions, epigenetic alterations and dysregulations in ATC, and highlighted several signaling cascades which appeared to be integral to ATC pathogenesis. Moreover, these features offer insights into de-differentiated, aggressive and drug-resistant phenotype of ATC, and thus may help in exploring potential new molecular targets for developing novel therapeutics.

CircRNA circRNA_102171 promotes papillary thyroid cancer progression through modulating CTNNBIP1-dependent activation of β-catenin pathway

Background

As a type of recently discovered noncoding RNA, circular RNAs (circRNAs) exert pivot biological functions in diverse cancers. However, the role of circRNA_102171 in papillary thyroid cancer (PTC) has not been investigated. Our study was focused on the functional investigation toward circRNA_102171 in PTC progression. And we also aimed to reveal its potential molecular mechanism.

Methods

The expression pattern of circRNA_102171 was determined using quantitative polymerase chain reaction (qPCR) in PTC samples and cell lines. Cell proliferation was examined utilizing CCK8, colony formation and EdU incorporation assays. Apoptosis was analyzed by Annexin V/PI staining and FACS detection. Cell migration and invasion was measured using Transwell assay. Tumor growth in vivo was determined through a xenograft assay. RNA-pulldown, RNA-IP (RIP) and RNA-EMSA were used to analyze the interaction between circRNA_102171 and CTNNBIP1.

Results

CircRNA_102171 expression was upregulated in tumor tissues and cell lines. CircRNA_102171 silencing suppressed PTC cell proliferation, migration and invasion while promoting apoptosis. CircRNA_102171 knockdown inhibited PTC growth in vivo. CircRNA_102171 interacted with CTNNBIP1 to block its interaction with the β-catenin/TCF3/TCF4/LEF1 complex, leading to activation of Wnt/β-catenin pathway.

Conclusions

CircRNA_102171 overexpression promotes PTC progression through activating Wnt/β-catenin pathway in a CTNNBIP1-dependent way.

LncRNA BISPR promotes the progression of thyroid papillary carcinoma by regulating miR-21-5p

Our study attempted to verify the effect of lncRNA BST2 interferon-stimulated positive regulator (BISPR) on cell viability, propagation and invasiveness of thyroid papillary carcinoma (TPC) and the interactive relationship between BISPR and miR-21-5p. Microarray analyzed the aberrant expression lncRNA BISPR in TPC. BISPR and miR-21-5p as well as B-cell lymphoma-2 (Bcl-2) expressions in TPC cells were determined by quantitative polymerase chain reaction (qRT-PCR) and Western blot. Cell counting kit-8 (CCK-8) assay, dual luciferase reporter assay, and transwell assay were conducted to manifest cell viability, propagation, and invasiveness of TPC cells. Flow cytometry was performed to determine the apoptosis and cell cycle of TPC cells. Mouse xenograft model was built to testify the effect of BISPR on tumor growth. BISPR in TPC tissues was over-expressed. BISPR knockdown restrained the propagation and invasiveness and enhanced the iodine uptake of TPC cells. The tumor-forming rate reduced after BISPR knockdown. In addition, miR-21-5p was lowly expressed in cancer tissues. BISPR promoted the development of TPC cells by inhibiting miR-21-5p expression. Bcl-2 was suppressed by miR-21-5p and sh-BISPR. BISPR, which was over-expressed in TPC, improved TPC cell viability, propagation, and invasiveness. MiR-21-5p was lowly expressed in TPC which inhibited Bcl-2 expression. BISPR stimulated propagation and invasiveness of TPC cells by depressing miR-21-5p.

Long non-coding RNAs in thyroid cancer: Biological functions and clinical significance

Thyroid cancer is the most common endocrine malignant tumor with rapidly increasing incidence in recent decades. Although the majority of thyroid cancers are relatively indolent, some cases still have a risk of developing into more aggressive and lethal forms of thyroid cancers. Similar to other malignancies, thyroid tumorigenesis is a multistep process involving the accumulation of a large number of genetic and epigenetic alterations. Thus, determination of the mechanisms of tumorigenesis is an urgent need for thyroid cancer treatment. Long noncoding RNAs (LncRNAs) have recently been demonstrated to participate in cancer progression. However, their role and molecular mechanism in thyroid cancer remain largely unclear. In this review, we focus on the dysregulation of lncRNAs in thyroid cancer, summarize the latest findings regarding the functions and mechanism of lncRNAs in thyroid cancer, and discuss their potential clinical significance in diagnosis and prognosis of thyroid cancer.

Long Noncoding RNA LINC003121 Inhibits Proliferation and Invasion of Thyroid Cancer Cells by Suppression of the Phosphatidylinositol-3-Kinase (PI3K)/Akt Signaling Pathway

BACKGROUND The aim of this study was to explore the potential effects of long noncoding RNA (lncRNA) LINC003121 on thyroid cancer (TC) cell proliferation and invasion and to explore their possible mechanisms with the involvement of the PI3K/Akt signaling pathway. MATERIAL AND METHODS We enrolled 211 thyroid cancer tissues and 70 adjacent normal tissues in this study. TC cell lines K1, SW579, and 8505C and the human thyroid follicular cell line Nthy-ori3-1 were selected and assigned into blank, control vectors, LINC00312 vectors, si-control, and si-LINC00312 groups. Quantitative real-time PCR was used to determine the levels of LINC003121 and Western blotting was used to detect the protein expression of MMP-9, PI3K, t-Akt, and p-Akt. Cell proliferation was assessed by CCK8 assay and EdU incorporation assay, and cell invasion was assessed by Transwell assay. RESULTS The expression of LINC00312 was significantly decreased in TC tissues and cell lines. In an in vitro experiment, si-LINC00312 significantly promoted the invasion and proliferation of TC cells. Conversely, overexpression of LINC00312 decreased cell proliferation and invasion in vitro, and decreased tumorigenicity in TC xenograft models in nude mice. LINC00312-mediated tumor suppression in TC cells may occur via suppression of activation of the PI3K/Akt signaling pathway and expression of MMP-9, and the role of MMP-9 expression induced by overexpressed LINC00312 or si-LINC00312 could be weakened by LY294002 (PI3K inhibitor). CONCLUSIONS LINC00312 can act as a tumor-suppressor in TC by attenuating the PI3K/Akt signaling pathway, and LINC00312 could be a novel diagnosis biomarker and a promising therapeutic target for TC patients.

LncRNA TNRC6C-AS1 regulates UNC5B in thyroid cancer to influence cell proliferation, migration, and invasion as a competing endogenous RNA of miR-129-5p

To investigate the biological functions and regulatory mechanism of lncRNA TNRC6C-AS1 in thyroid cancer (TC). TNRC6C-AS1, miR-129-5p, and UNC5B expression levels were investigated by qRT-PCR and Western blot. CCK-8 assay was conducted to determine cell proliferation, while transwell assay was for inspection of cell migration and invasion. Through bioinformatic analysis, the interactions among TNRC6C-AS1, miR-129-5p, and UNC5B were predicted. Dual luciferase reporter gene assay and RNA pull-down assay confirmed the predicted target relationships. Tumor xenograft assay was applied to inspect the effect of TNRC6C-AS1 downregulation on TC development in vivo. TNRC6C-AS1 and UNC5B were overexpressed, while miR-129-5p was underexpressed in TC tissues and cells. TNRC6C-AS1/UNC5B downregulation and miR-129-5p overexpression could suppress proliferation, migration, and invasion of TC cells as well as inhibit tumorigenesis in vivo. MiR-129-5p targeted TNRC6C-AS1 and UNC5B in TC cells; and UNC5B expression was downregulated by knocking down TNRC6C-AS1, which competitively bound with miR-129-5p. Downregulation of TNRC6C-AS1 restrained TC development by knocking down UNC5B through upregulating the expression of miR-129-5p.

Expression of BANCR promotes papillary thyroid cancer by targeting thyroid stimulating hormone receptor

Papillary thyroid carcinoma (PTC) is the most common form of non-medullary thyroid cancer, accounting for ~80% of all cases of thyroid cancer. The aim of the present study was to explore the role of BRAF-activated long noncoding RNA (BANCR) in the development of PTC. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the mRNA expression levels of BANCR, thyroid-stimulating hormone receptor (TSHR) and cyclin D1 between PTC and benign control thyroid nodule tissue samples from 60 patients were determined. Using RT-qPCR and western blot analysis, the expression levels of TSHR and cyclin D1 mRNA and protein were determined in cells transfected with BANCR-small interfering (si)RNA. An MTT assay and flow cytometry were used to analyze the effect of BANCR knockdown on the proliferation and cell cycle distribution of IHH-4 PTC cells. The expression of BANCR, TSHR and cyclin D1 was increased in the PTC group compared with the control group based on the RT-qPCR data. The transfection of IHH-4 cells with BANCR-siRNA induced the inhibition of TSHR and cyclin D1 expression compared with a transfection control. In addition, the proliferation of the IHH-4 cells transfected with BANCR-siRNA was suppressed, relative to the transfection control, and cells arrested in the G0/G1 phase, potentially due to the inhibition of the expression of cyclin D1. The data suggested that the expression of BANCR may promote the development of malignant thyroid nodules via the modulation of TSHR expression and its downstream effector, cyclin D1.

Long noncoding RNA PVT1 enhances the viability and invasion of papillary thyroid carcinoma cells by functioning as ceRNA of microRNA-30a through mediating expression of insulin like growth factor 1 receptor

OBJECTIVE

Invasion and metastasis of papillary thyroid carcinoma (PTC) significantly affects prognosis and quality of life of patients. Herein, we explored the binding relationship of long noncoding RNA PVT1 as ceRNA to microRNA-30a (miR-30a), and their effect on the development of PTC through regulating insulin like growth factor 1 receptor (IGF1R).

METHODS

PTC and adjacent normal tissues were collected, where the qRT-PCR and western blot assay were employed to evaluate the expression levels of PVT1, miR-30a and IGF1R. The correlation between PVT1 expression and clinicopathological characteristics of PTC patients was observed. PTC cell lines with the most/least significant difference from normal thyroid cells were selected and treated with siRNA PVT1 or overexpression PVT1 plasmids, miR-30a mimics or miR-30a inhibitors. Nucleus and cytoplasm segmentation was used to identify subcellular fractionation of PVT1. The binding relationship of PVT1 to miR-30a and the targeting relationship of miR-30a to IGF1R were confirmed by using bioinformatic prediction program, dual-luciferase reporter gene assay and RNA-pull down. Cell viability, cell cycle and apoptosis, invasion and migration capacities were assessed by MTT, flow cytometry, Transwell assay and scratch test, respectively. Western blot assay was employed to examine protein expression of IGF1R, apoptosis-related factors (caspase-3, cleaved capase-3) and epithelial-mesenchymal transition (EMT)-related factors (E-cadherin, Vimentin).

RESULTS

In the PTC tissues and cells, PVT1 and IGF1R were highly expressed and miR-30a was poorly expressed. PVT1 exerted its effects on PTC mainly in the cytoplasm. The PVT1 expression was correlated with TNM staging, LNM and tumor infiltration of PTC. The competitive binding of PVT1 to miR-30a enhanced expression of IGF1R. In the in vitro experiments, BCPAP and TPC-1 cells were selected. When subjected to siRNA PVT1 or miR-30a mimics, BCPAP and TPC-1 cells exhibited inhibited proliferation, cell cycle progression, invasion, migration, EMT (increased E-cadherin and reduced Vimentin) and promoted apoptosis (reduced caspase-3 and increased cleaved capase-3), and moreover, the expression of IGF1R was reduced.

CONCLUSION

This study provides evidence that long noncoding RNA PVT1 enhances the expression of IGF1R through competitive binding to miR-30a, whereby PVT1 facilitates the development of PTC.

Long non-coding RNA BRAF-regulated lncRNA 1 promotes lymph node invasion, metastasis and proliferation, and predicts poor prognosis in breast cancer

Long non-coding RNAs (lncRNAs) are primary regulators of cancer development via their involvement in almost every aspect of cell biology. Recent studies have indicated that lncRNAs serve pivotal roles in breast cancer (BC) progression; however, to the best of our knowledge, the role of the lncRNA BRAF-regulated lncRNA 1 (BANCR) in BC has not yet been elucidated. The present study revealed that BANCR was overexpressed in BC cell lines and tissues, and could promote the clinical progression of disease, including increases in tumor size, lymph node metastasis and Tumor-Node-Metastasis stage. Furthermore, high BANCR expression was demonstrated to be associated with poor overall survival rates and early recurrence of BC in patients. Additionally, univariate and multivariate COX regression analyses identified high BANCR expression as an independent risk factor of poor prognosis of patients with BC. In addition, to verify the function of BANCR in BC cell lines, BANCR expression was silenced using short hairpin RNAs in MDA-MB-231 cells and overexpressed in MDA-MB-468 cells. An MTT assay and colony formation assay indicated that BANCR knockdown could suppress the proliferation of BC cells, whereas BANCR upregulation induced the proliferation of BC cells. Furthermore, BANCR silencing also reduced the migration and invasion of BC cells, as demonstrated via transwell migration and invasion assays. Consistently, the migration and invasion of BC cells increased upon BANCR ectopic overexpression in MDA-MB-468 cells. Mechanistically, matrix metallopeptidase 2/9 and epithelial-mesenchymal transition markers may be the potential targets of BANCR in regulating BC metastasis. In conclusion, BANCR overexpression could promote the clinical progression, metastasis and proliferation of BC and indicate poor prognosis of patients with BC. BANCR may therefore be a potential prognostic marker and therapeutic target of patients with BC.

The BRAF activated non-coding RNA: A pivotal long non-coding RNA in human malignancies

Long non-coding RNAs (lncRNAs) participate in the complex network of cancer and play an important role in tumourigenesis and progression. BRAF activated non-coding RNA (BANCR), a 4-exon transcript of 693-bp, was first discovered as an oncogenic long non-coding RNA in BRAF^V600E melanomas cells in 2012 and was related to melanoma cell migration. Besides melanoma, increasing evidence has explored the potential role of BANCR in the development and progression of multiple other human malignancies, such as retinoblastoma, lung cancer, gastric cancer etc. since its discovery. The expression pattern of BANCR varies in different types of cancers, either as a tumour suppressor or as an accelerator. Functional BANCR may serve as a promising biomarker for cancer diagnosis as well as prognosis evaluation. BANCR-targeted intervention may also become a valuable novel therapeutic tool against human malignancies. This review summarized the advanced research progresses concerning the expression and role of BANCR in different human malignancies.

BRAF-activated LncRNA functions as a tumor suppressor in papillary thyroid cancer

Long non-coding RNAs (lncRNAs) participate in cancer cell tumorigenesis, cell cycle control, migration, proliferation, apoptosis, metastasis and drug resistance. The BRAF-activated non-coding RNA (BANCR) functions as both an oncogene and a tumor suppressor. Here, we investigated BANCR's role in papillary thyroid carcinoma (PTC) by assessing BANCR levels in PTC and matched normal thyroid epithelial tissues from 92 patients using qRT-PCR. We also used lentiviral vectors to establish PTC cell lines to investigate the effects of BANCR overexpression on cancer cell proliferation, apoptosis, migration and invasion. Our results indicate BANCR levels are lower in PTC tumor tissues than control tissues. Decreased BANCR levels correlate with tumor size, the presence of multifocal lesions and advanced PTC stage. BANCR overexpression reduced PTC cell proliferation and promoted apoptosis, which inhibited metastasis. It also inactivated ERK1/2 and p38, and this effect was enhanced by treatment with the MEK inhibitor U0126. Finally, BANCR overexpression dramatically inhibited tumor growth from PTC cells in xenograft mouse models. These results suggest BANCR inhibits tumorigenesis in PTC and that BANCR levels may be used as a novel prognostic marker.

lncRNA BANCR promotes EMT in PTC via the Raf/MEK/ERK signaling pathway

Thyroid cancer is one of the most common types of cancer in the endocrine system. Among all types of thyroid cancer, papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Long non-coding RNA (lncRNA) BRAF-activated non-protein-coding RNA (BANCR) is a 688-bp-long nucleotide transcript, which was first identified in melanoma. The function of BANCR in thyroid cancer remains unclear. The aim of the present study was to investigate whether BANCR is involved in the development of thyroid cancer. The results indicated that BANCR expression was increased in thyroid tumors compared with in adjacent normal tissues. Among cancer cell lines, the expression level of BANCR differed: BANCR expression in BCPAP cell lines was lower compared with that in CAL-62, WRO and FTC-133 cell lines. Overexpression of BANCR promoted the migration and invasion of BCPAP cells. Additionally, BANCR mediated epithelial-mesenchymal transition (EMT) by regulating the expression of epithelial (E)-cadherin, vimentin and neuronal (N)-cadherin. Overexpression of BANCR in BCPAP cells decreased the expression of E-cadherin and increased the expression of vimentin, N-cadherin, phospho (p)-c-Raf, p-extracellular-signal-regulated kinase (ERK)/mitogen activated protein kinase (MEK)1/2 and p-ERK1/2. Administration of U0126 inhibitor inhibited the regulation of phosphorylation levels by MEK1/2 and ERK1/2. Additionally, U0126 upregulated the expression of E-cadherin and downregulated the expression of vimentin. Taken together, the results of the present study suggest that BANCR induces EMT in PTC through the Raf/MEK/ERK signaling pathway.

Long noncoding RNAs: emerging players in thyroid cancer pathogenesis

Thyroid cancer continues to be the most common malignancy of endocrine glands. The incidence of thyroid cancer has risen significantly over the past 4 decades and has emerged as a major health issue. In recent years, significant progress has been achieved in our understanding of the molecular mechanisms of thyroid carcinogenesis, resulting in significant diagnostic, prognostic and therapeutic implications; yet, it has not reached a satisfactory level. Identifying novel molecular therapeutic targets and molecules for diagnosis and prognosis is expected to advance the overall management of this common malignancy. Long noncoding RNAs (lncRNAs) are implicated in the regulation of various key cellular genes involved in cell differentiation, proliferation, cell cycle, apoptosis, migration and invasion mainly through modulation of gene expression. Recent studies have established that lncRNAs are deregulated in thyroid cancer. In this review, we discuss extensively the tumor-suppressive (for example, LINC00271, MEG3, NAMA, PTCSC1/2/3, etc.) and oncogenic (for example, ANRIL, FAL1, H19, PVT1, etc.) roles of various lncRNAs and their possible disease associations implicated in thyroid carcinogenesis. We briefly summarize the strategies and mechanisms of lncRNA-targeting agents. We also describe the potential role of lncRNAs as prospective novel therapeutic targets, and diagnostic and prognostic markers in thyroid cancer.

Current research on head and neck cancer-associated long noncoding RNAs

Head and neck cancers (HNC) are one of the ten leading cancers worldwide, including a range of malignant tumors arising from the upper neck. Due to the complex mechanisms of HNC and lack of effective biomarkers, the 5-year survival rate of HNC has been low and the mortality rate has been high in recent decades. Long noncoding RNAs (lncRNAs), noncoding RNAs longer than 200 bps, are a focus of current cancer research, closely related to tumor biology. LncRNAs have been revealed to be aberrantly expressed in various types of HNC, and the dysregulated lncRNAs participate in HNC progression and induce malignant behavior by modulating gene expression at diverse levels. This review will focus on the functions and molecular mechanisms of dysregulated lncRNAs in HNC tumorigenesis and progression, as well as their diagnostic, therapeutic or prognostic implications in HNC.

Prognostic Role of Long Noncoding RNA BANCR in Solid Tumors: A Meta-Analysis

Accumulating studies have reported that long noncoding RNA BRAF-activated nonprotein coding RNA plays vital role in various cancers. However, the prognostic values of BRAF-activated nonprotein coding RNA in solid tumors remain controversial. Thus, we assessed the prognostic values of BRAF-activated nonprotein coding RNA by this meta-analysis. We comprehensively searched PubMed, Web of Science, Medline, China National Knowledge Infrastructure (CNKI), and the Cochrane Library at November 2016. After carefully screening, we ultimately included 14 studies in this meta-analysis. This meta-analysis brought all relevant articles into determining the association of BRAF-activated nonprotein coding RNA expression with overall survival and clinicopathologic features. The results showed that high BRAF-activated nonprotein coding RNA expression significantly shorten the overall survival of solid tumors (pooled hazard ratios 1.66, 95% confidence interval: 1.19-2.32). Moreover, high BRAF-activated nonprotein coding RNA expression was also strongly associated with advanced tumor stage (odds ratios = 2.57, 95% confidence interval: 1.14-5.79), differentiation grade (odds ratio = 1.71, 95% confidence interval: 1.26-2.31), lymph node metastasis (odds ratio = 2.67, 95% confidence interval: 1.93-3.70, P < .001), and distant metastasis (odds ratio = 2.98, 95% confidence interval: 1.76-5.07, P = .02). In conclusion, this meta-analysis demonstrated that high BRAF-activated nonprotein coding RNA expression may be a potential novel biomarker for indicating a poor prognosis and progression in human solid tumors.

MicroRNA-335 is downregulated in papillary thyroid cancer and suppresses cancer cell growth, migration and invasion by directly targeting ZEB2

MicroRNAs (miRs) are a group of short, endogenous, non-protein-coding and single-stranded RNAs that regulate gene expression by binding to the 3'-untranslated region (3'UTR) of mRNAs, which results in their degradation or translational repression. The aim of the present study was to investigate the expression and function of miR-335 in human papillary thyroid cancer (PTC). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to quantify the relative miR-335 expression levels in PTC tissues and cell lines. The effect of miR-335 on the proliferation, migration and invasion of PTC cells was assessed by an MTT assay, and transwell migration and invasion assays, respectively. Dual-luciferase reporter assays were employed to explore whether miR-335 directly targeted the 3'UTR of the potential target gene zinc finger E-box binding homeobox 2 (ZEB2). RT-qPCR and western blotting were adopted to assess the effect of miR-335 on the mRNA and protein expression of ZEB2. RT-qPCR revealed that miR-335 was downregulated in PTC tissues and cell lines. The MTT assay and transwell migration and invasion assays demonstrated that the overexpression of miR-335 significantly inhibited the proliferation, migration and invasion of PTC cells. ZEB2 was identified as a direct target of miR-335 with computational analysis, which was confirmed with a dual-luciferase reporter assay, RT-qPCR and western blotting. The knockdown of ZEB2 significantly inhibited the proliferation, migration and invasion of PTC cells, indicating that ZEB2 may be a functional target of miR-335. Taken together, these findings suggested that miR-335 functioned as a tumor suppressor and suppressed the growth and metastatic behavior of PTC cells by targeting ZEB2.

Periostin silencing suppresses the aggressive phenotype of thyroid carcinoma cells by suppressing the Akt/thyroid stimulating hormone receptor axis

Clinical evidence indicates that high periostin expression correlates with aggressive phenotype in thyroid carcinoma. However, the biological roles of periostin in thyroid carcinoma development and progression are still unclear. In this study, we explored the effects of periostin silencing on thyroid carcinoma cell growth, invasion, and tumorigenesis. We also studied the impact of periostin on the activation of phosphoinositide 3-kinase (PI3-K)/Akt signaling, which is involved in the pathogenesis of thyroid carcinoma. It was found that downregulation of periostin significantly inhibited the proliferation, colony formation, and invasion in both FTC-133 and BCPAP thyroid carcinoma cells. In vivo tumorigenic studies confirmed that periostin depletion retarded the growth of subcutaneous FTC-133 xenograft tumors, which was coupled with a significant decline in the percentage of Ki-67-positive proliferating cells. Western blot analysis demonstrated that periostin downregulation caused a marked inhibition of thyroid stimulating hormone receptor (TSHR) expression and Akt phosphorylation in FTC-133 and BCPAP cells. Co-expression of constitutively active Akt (CA-Akt) significantly reversed periostin-mediated downregulation of TSHR. Most importantly, overexpression of TSHR or CA-Akt rescued FTC-133 cells from periostin-induced growth and invasion suppression. Collectively, periostin regulates thyroid carcinoma growth and progression via the Akt/TSHR axis and represents a promising therapeutic target for this malignancy.