Differential expression profiling and functional analysis of microRNAs through stage I-III papillary thyroid carcinoma

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.

Gene targeted and immune therapies for nodal and gastrointestinal follicular lymphomas

Follicular lymphoma (FL) is the most common indolent B-cell lymphoma (BCL) globally. Recently, its incidence has increased in Europe, the United States, and Asia, with the number of gastrointestinal FL cases expected to increase. Genetic abnormalities related to t(14;18) translocation, BCL2 overexpression, NF-κB pathway-related factors, histone acetylases, and histone methyltransferases cause FL and enhance its proliferation. Meanwhile, microRNAs are commonly used in diagnosing FL and predicting patient prognosis. Many clinical trials on novel therapeutics targeting these genetic abnormalities and immunomodulatory mechanisms have been conducted, resulting in a marked improvement in therapeutic outcomes for FL. Although developing these innovative therapeutic agents targeting specific genetic mutations and immune pathways has provided hope for curative options, FL treatment has become more complex, requiring combinatorial therapeutic regimens. However, optimal treatment combinations have not yet been achieved, highlighting the importance of a complete under-standing regarding the pathogenesis of gastrointestinal FL. Accordingly, this article reviews key research on the molecular pathogenesis of nodal FL and novel therapies targeting the causative genetic mutations. Moreover, the results of clinical trials are summarized, with a particular focus on treating nodal and gastrointestinal FLs.

Large-scale transcriptomic analysis of coding and non-coding pathological biomarkers, associated with the tumor immune microenvironment of thyroid cancer and potential target therapy exploration

Papillary thyroid carcinoma (PTC) is the most prevalent endocrine malignancy with a steadily increasing global incidence in recent decades. The pathogenesis of PTC is poorly understood, and the present diagnostic protocols are deficient. Thus, identifying novel prognostic biomarkers to improve our understanding of the mechanisms of pathogenesis, diagnosis, and designing therapeutic strategies for PTC is crucial. In this study, we integrated 27 PTC transcriptomic datasets and identified overlapping differentially expressed genes (DEGs) and differentially expressed microRNAs, collectively known as thyroid tumor-enriched proteins (TTEPs), and TTEmiRs, respectively. Our integrated bioinformatics analysis revealed that TTEPs were associated with tumor stages, poor surgical outcomes, distant metastasis, and worse prognoses in PTC cohorts. In addition, TTEPs were found to be associated with tumor immune infiltrating cells and immunosuppressive phenotypes of PTC. Enrichment analysis suggested the association of TTEPs with epithelial-to-mesenchymal transition (EMT), cell-matrix remodeling, and transcriptional dysregulation, while the TTEmiRs (miR-146b-5p and miR-21-5p) were associated with the modulation of the immune response, EMT, migration, cellular proliferation, and stemness. Molecular docking simulations were performed to evaluate binding affinities between TTEPs and antrocinnamomin, antcin, and antrocin, the bioactive compounds from one of the most reputable Taiwan indigenous medicinal plants (Antrodia camphorata). Our results revealed that antcin exhibited higher binding efficacies toward FN1, ETV5, and NRCAM, whereas antrocin demonstrated the least. Among the targets, fibronectin (FN1) demonstrated high ligandability potential for the compounds whereas NRCAM demonstrated the least. Collectively, our results hinted at the potential of antcin for targeting TTEPs. In conclusion, this comprehensive bioinformatics analysis strongly suggested that TTEPs and TTEmiRs could be used as potential diagnostic biomarker signatures and be exploited as potential targets for therapeutics development.

MiR-9-3p regulates the biological functions and drug resistance of gemcitabine-treated breast cancer cells and affects tumor growth through targeting MTDH

This study explored the role of MTDH in regulating the sensitivity of breast cancer cell lines to gemcitabine (Gem) and the potential miRNAs targeting MTDH. The expression of MTDH in cancer tissues and cells was detected by immunohistochemical staining or qRT-PCR. The target genes for MTDH were predicted by bioinformatics and further confirmed by dual-luciferase reporter assay and qRT-PCR. Cancer cells were transfected with siMTDH, MTDH, miR-9-3p inhibitor, or mimics and treated by Gem, then CCK-8, colony formation assay, tube formation assay, flow cytometry, wound healing assay, and Transwell were performed to explore the effects of MTDH, miR-9-3p, and Gem on cancer cell growth, apoptosis, migration, and invasion. Expressions of VEGF, p53, cleaved caspase-3, MMP-2, MMP-9, E-Cadherin, N-Cadherin, and Vimentin were determined by Western blot. MTDH was high-expressed in cancer tissues and cells, and the cells with high-expressed MTDH were less sensitive to Gem, while silencing MTDH expression significantly promoted the effect of Gem on inducing apoptosis, inhibiting cell migration, invasion, and growth, and on regulating protein expressions of cancer cells. Moreover, miR-9-3p had a targeted binding relationship with MTDH, and overexpressed miR-9-3p greatly promoted the toxic effects of Gem on cancer cells and expressions of apoptosis-related proteins, whereas overexpressed MTDH partially reversed such effects of overexpressed miR-9-3p. The study proved that miR-9-3p regulates biological functions, drug resistance, and the growth of Gem-treated breast cancer cells through targeting MTDH.

Silencing circRNA protein kinase C iota (circ-PRKCI) suppresses cell progression and glycolysis of human papillary thyroid cancer through circ-PRKCI/miR-335/E2F3 ceRNA axis

The circular RNA PRKCI (circ-PRKCI; ID: hsa_circ_0122683) is highly expressed in human papillary thyroid cancer (PTC) tumors according to GSE93522 dataset. However, its role in PTC tumorigenesis remains to be documented. Here, quantitative real-time PCR showed that expression of circ-PRKCI was abnormally upregulated in human PTC patients' tumors and cells, and higher circ-PRKCI might predict lymph node metastasis and recurrence. Functionally, cell behaviors were measured by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay, colony formation assay, fluorescence-activated cell sorting method, scratch wound assay, transwell assay, western blotting, and assay kits for glucose and lactate. As a result, circ-PRKCI knockdown could suppress cell cycle progression of PTC cells and restrain the abilities of cell proliferation, colony formation, wound closure, invasion, glucose consumption and lactate production, accompanied with decreased levels of matrix metalloproteinase-2 (MMP2), MMP9 and Snail. Moreover, above-mentioned inhibition could be imitated by overexpressing microRNA-335-5p (miR-335). Molecularly, circ-PRKCI functioned as a sponge for miR-335 and miR-335 could further targeted E2F transcription factor-3 (E2F3), according to dual-luciferase reporter assay and RNA immunoprecipitation. However, downregulating miR-335 diminished the effects of circ-PRKCI role on cell growth, metastasis and glycolysis in PTC cells; besides, there was a counteractive effect between miR-335 upregulation and E2F3 upregulation in PTC cells as well. Furthermore, xenograft experiment revealed that silencing circ-PRKCI could retard tumor growth of PTC cells in vivo. Collectively, circ-PRKCI exerted oncogenic role in PTC by antagonizing cell progression and glycolysis via regulating miR-335/E2F3 axis, suggesting circ-PRKCI was a potential biomarker and target for PTC.

MiR-30a and miR-200c differentiate cholangiocarcinomas from gastrointestinal cancer liver metastases

Prior studies have demonstrated the utility of microRNA assays for predicting some cancer tissue origins, but these assays need to be further optimized for predicting the tissue origins of adenocarcinomas of the liver. We performed microRNA profiling on 195 frozen primary tumor samples using 14 types of tumors that were either adenocarcinomas or differentiated from adenocarcinomas. The 1-nearest neighbor method predicted tissue-of-origin in 33 samples of a test set, with an accuracy of 93.9% at feature selection p values ranging from 10-4 to 10-10. According to binary decision tree analyses, the overexpression of miR-30a and the underexpression of miR-200 family members (miR-200c and miR-141) differentiated intrahepatic cholangiocarcinomas from extrahepatic adenocarcinomas. When binary decision tree analyses were performed using the test set, the prediction accuracy was 84.8%. The overexpression of miR-30a and the reduced expressions of miR-200c, miR-141, and miR-425 could distinguish intrahepatic cholangiocarcinomas from liver metastases from the gastrointestinal tract.

Mapping the Molecular Basis and Markers of Papillary Thyroid Carcinoma Progression and Metastasis Using Global Transcriptome and microRNA Profiling

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer (TC). In a subgroup of patients with PTC, the disease progresses to an invasive stage or in some cases to distant organ metastasis. At present, there is an unmet clinical and diagnostic need for early identification of patients with PTC who are at risk of disease progression or metastasis. In this study, we report several molecular leads and potential biomarker candidates of PTC metastasis for further translational research. The study design was based on comparisons of PTC in three different groups using cross-sectional sampling: Group 1, PTC localized to the thyroid (n = 20); Group 2, PTC with extrathyroidal progression (n = 22); and Group 3, PTC with distant organ metastasis (n = 20). Global transcriptome and microRNAs (miRNA) analyses were conducted using an initial screening set comprising nine formalin-fixed paraffin-embedded PTC samples obtained from three independent patients per study group. The findings were subsequently validated by quantitative real-time polymerase chain reaction (qRT-PCR) using the abovementioned independent patient sample set (n = 62). Comparative analyses of differentially expressed miRNAs showed that miR-193-3p, miR-182-5p, and miR-3607-3p were novel miRNAs associated with PTC metastasis. These potential miRNA biomarkers were associated with TC metastasis and miRNA-target gene associations, which may provide important clinicopathological information on metastasis. Our findings provide new molecular leads for further translational biomarker research, which could facilitate the identification of patients at risk of PTC disease progression or metastasis.

A three plasma microRNA signature for papillary thyroid carcinoma diagnosis in Chinese patients

Whether plasma miRNAs could be used as novel non-invasive biomarkers in diagnosing papillary thyroid carcinoma (PTC) remains unknown. In this study, we designed a four-phase study to identify differentially expressed plasma miRNAs in Chinese PTC patients. Exiqon panel was initially utilized to conduct plasma miRNA profile (3 PTC pools VS. 1 healthy control (HC) pool; each 10 samples were pooled as 1 sample). The dysregulated miRNAs were then analyzed in the training (30 PTC VS. 30 HCs), testing (57 PTC VS. 54 HCs) and external validation phases (33 PTC VS. 30HCs). The identified miRNAs were further affirmed in benign nodules (2 nodular goiter (NG) pool VS. 1 HC pool). We also verified the expression of identified miRNAs in 17 matched malignant and normal tissue samples, NG plasma samples (29 PTC VS. 29 NG) and plasma exosomes (25 PTC VS. 25 HCs). Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic value of the identified miRNAs. As a result, the screening phase demonstrated 30 dysregulated plasma miRNAs in PTC patients compared with HCs. After multiphase experiment processes, miR-346, miR-10a-5p and miR-34a-5p were found significantly elevated in PTC plasma samples relative to HCs. The areas under the ROC curve (AUC) of the three-miRNA panel for the training, testing and validation phases were 0.926, 0.811 and 0.816, separately. The panel could also differentiate PTC from NG with the AUC of 0.877. MiR-346 and miR-34a-5p but not miR-10a-5p were up-regulated in PTC tissues. And the three miRNAs showed consistently up-regulation in PTC plasma exosomes. In conclusion, our study established a three-miRNA panel in plasma with considerable clinical value in discriminating PTC from HC or NG.

MicroRNA-146b-3p Promotes Cell Metastasis by Directly Targeting NF2 in Human Papillary Thyroid Cancer

Background: MiR-146b has been reported to be overexpressed in papillary thyroid cancer (PTC) tissues and associated with aggressive PTC. MiR-146b is regarded as a relevant diagnostic marker for this type of cancer. MiR-146b-5p has been confirmed to increase cell proliferation by repressing SMAD4. However, detailed functional analysis of another mature form of miR-146b, miR-146b-3p, has not been carried out. This study aimed to identify the differential expression of miR-146b-5p and miR-146b-3p in more aggressive PTC associated with lymph node metastasis, and further elucidate the contribution and mechanism of miR-146b-3p in the process of PTC metastasis. Methods: Expression of miR-146b-5p and miR-146b-3p was assessed in formalin-fixed paraffin-embedded tissue samples from PTC patients, and the relationship with lymph node metastasis was analyzed. A variety of PTC cells, including BHP10-3, BHP10-3SC_mice, and K1 cells, were cultured and treated with miR-146b-5p or miR-146b-3p mimics/inhibitors. The cell migration and invasion abilities were characterized by the real-time cell analyzer assay and Transwell™ assay. PTC xenograft models were used to examine the effect of miR-146b-3p on PTC metastatic ability in vivo. Direct downstream targets of miR-146b-3p were analyzed by luciferase reporter assay and Western blotting. The mechanism by which miR-146b-3p affects cell metastasis was further characterized by co-transfection with merlin, the protein product of the NF2 gene. Results: MiR-146b-5p and miR-146b-3p expression was significantly higher in thyroid cancer tissues and cell lines than in normal thyroid tissue and cells. Moreover, expression of miR-146b-5p and miR-146b-3p was further increased in thyroid metastatic nodes than in thyroid cancer. After overexpression of miR-146b-5p or miR-146b-3p in BHP10-3 or K1 cells, PTC migration and invasion were increased. Notably, miR-146b-3p increased cell migration and invasion more obviously than did miR-146b-5p. Overexpression of miR-146b-3p also significantly promoted PTC tumor metastasis in vivo. Luciferase reporter assay results revealed that NF2 is a downstream target of miR-146b-3p in PTC cells, as miR-146b-3p bound directly to the 3' untranslated region of NF2, thus reducing protein levels of NF2. Overexpression of merlin reversed the enhanced aggressive effects of miR-146b-3p. Conclusions: Overexpression of miR-146b-5p and miR-146b-3p is associated with PTC metastasis. MiR-146b-3p enhances cell invasion and metastasis more obviously than miR-146b-5p through the suppression of the NF2 gene. These findings suggest a potential diagnostic and therapeutic value of these miRNAs in PTC metastasis.

MicroRNA-146b-5p as an oncomiR promotes papillary thyroid carcinoma development by targeting CCDC6

The microRNA-146b-5p (miR-146b-5p) is known to be involved in the development of papillary thyroid cancer (PTC); however, the underlying mechanism is unclear. Here we have investigated the biological functions and underlying molecular mechanisms of miR-146b-5p in PTC. The expression of miR-146b-5p was assessed in 92 pairs of PTC and adjacent normal tissues and showed correlation with the clinicopathological status such as the tumour size. Effects of miR-146b-5p and its direct target, coiled-coil domain containing 6 (CCDC6), on cell proliferation, migration, invasion, and cell cycle were evaluated through gain- and loss-of-function studies in vitro and in vivo. The expression of CCDC6 was further examined in 187 PTC cases and was found to be correlated with the clinicopathological status. Overexpression of miR-146b-5p was observed in PTC tissues that correlated with advanced PTC. miR-146b-5p promoted cell proliferation, migration, invasion, and cell cycle progression in vitro, whereas CCDC6 reversed this effect. miR-146b-5p promoted PTC growth in a subcutaneous mouse model in vivo, whereas overexpression of CCDC6 exerted the opposite effect. In conclusion, miR-146b-5p expression correlated with advanced PTC and promoted PTC development by targeting CCDC6 in vitro and in vivo; it could, therefore, serve as a promising target for PTC treatment.

A potential biomarker hsa-miR-200a-5p distinguishing between benign thyroid tumors with papillary hyperplasia and papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common endocrine cancer with a significantly increase of the incidence recently. Several cytokines, such as thyroid peroxidase (TPO), cluster of differentiation 56 (CD56), Galectin-3, mesothelial cell (MC), cytokeratin 19 (CK19) and BRAF (B-raf) were recommended to be tested by immunohistochemistry (IHC) for a definitive diagnosis, but were still limited in clinical use because of their relative lower sensitivity and specificity. MicroRNA (miRNA), as a new molecular biomarkers, however, has not been reported yet so far. To address this, hsa-miR-200a-5p, a miRNA, was selected and detected in PTC patients by in situ hybrization with benign thyroid tumor with papillary hyperplasia as a control, and the differential expression of hsa-miR-200a-5p between fresh PTC tissues and control was detected by qRT-PCR. Expressive levels of cytokines of TPO, CD56, Galectin-3, MC, CK19 and B-raf were also detected by immunohistochemistry. The correlation was analyzed by SPSS software using Spearman methods. As expected, the hsa-miR-200a-5p expressive level was significantly increased in PTC patients, compared to that of control, and was consistent with that of TPO, CD56, Galectin-3, MC, CK19 and B-raf. In addition, expression of hsa-miR-200a-5p showed negative correlation to that of TPO (rs = - 0.734; **: P < 0.01) and CD56 (rs = - 0.570; **: P < 0.01), but positive correlation to that of Galectin-3 (rs = 0.601; **: P < 0.01), MC (rs = 0.508; **: P < 0.01), CK19 (rs = 0.712; **: P < 0.01) and B-raf (rs = 0.378; **: P < 0.01). PTC and papillary benign thyroid papillary hyperplasia are difficult to distinguish in morphology, so requiring immunohistochemistry to further differentiate the diagnosis, however, for the existing clinical common diagnostic marker for immunohistochemistry, the sensitivity and accuracy are low, it is easy to miss diagnosis. Therefore, there is an urgent need for a rapid and sensitive molecular marker. So miR-200a-5p can be used to assist in the diagnosis of PTC at the molecular level, and as a biomarker, can be effectively used to distinguish between PTC and benign thyroid tumor with papillary hyperplasia.

Competing endogenous RNA regulatory network in papillary thyroid carcinoma

The present study aimed to screen all types of RNAs involved in the development of papillary thyroid carcinoma (PTC). RNA-sequencing data of PTC and normal samples were used for screening differentially expressed (DE) microRNAs (DE-miRNAs), long non-coding RNAs (DE-lncRNAs) and genes (DEGs). Subsequently, lncRNA-miRNA, miRNA-gene (that is, miRNA-mRNA) and gene-gene interaction pairs were extracted and used to construct regulatory networks. Feature genes in the miRNA-mRNA network were identified by topological analysis and recursive feature elimination analysis. A support vector machine (SVM) classifier was built using 15 feature genes, and its classification effect was validated using two microarray data sets that were downloaded from the Gene Expression Omnibus (GEO) database. In addition, Gene Ontology function and Kyoto Encyclopedia Genes and Genomes pathway enrichment analyses were conducted for genes identified in the ceRNA network. A total of 506 samples, including 447 tumor samples and 59 normal samples, were obtained from The Cancer Genome Atlas (TCGA); 16 DE-lncRNAs, 917 DEGs and 30 DE-miRNAs were screened. The miRNA-mRNA regulatory network comprised 353 nodes and 577 interactions. From these data, 15 feature genes with high predictive precision (>95%) were extracted from the network and were used to form an SVM classifier with an accuracy of 96.05% (486/506) for PTC samples downloaded from TCGA, and accuracies of 96.81 and 98.46% for GEO downloaded data sets. The ceRNA regulatory network comprised 596 lines (or interactions) and 365 nodes. Genes in the ceRNA network were significantly enriched in ‘neuron development’, ‘differentiation’, ‘neuroactive ligand-receptor interaction’, ‘metabolism of xenobiotics by cytochrome P450’, ‘drug metabolism’ and ‘cytokine-cytokine receptor interaction’ pathways. Hox transcript antisense RNA, miRNA-206 and kallikrein-related peptidase 10 were nodes in the ceRNA regulatory network of the selected feature gene, and they may serve import roles in the development of PTC.

Down-regulation of 14q32-encoded miRNAs and tumor suppressor role for miR-654-3p in papillary thyroid cancer

Papillary thyroid carcinoma (PTC) is the most prevalent malignant neoplasia of the thyroid gland. A fraction of PTC cases show loss of differentiation and aggressive behavior, with radioiodine therapy resistance and metastasis. Although microRNAs (miRNAs) emerged as promising molecular markers for PTC, their role in the loss of differentiation observed during PTC progression remains to be fully understood. We performed the large-scale analysis of miRNA expression during PTC progression in BRAFT1799A-transgenic animals (Tg-Braf) and thyroid cancer cell lines and identified the marked downregulation of several miRNAs from the region 14q32. Data from The Cancer Genome Atlas (TCGA) confirmed the global downregulation of miRNAs from the 14q32 region in human PTC. The regulatory network potentially suppressed by these miRNAs suggests that key cancer-related biological processes such as cell proliferation, adhesion, migration and angiogenesis. Among the downregulated miRNAs, we observed that miR-654-3p levels decrease with long-term PTC progression in Tg-Braf mice and inversely correlate with EMT. The in vitro restoration of miR-654-3p decreased cell proliferation and migration and induced reprogramming of metastasis-related genes, suggesting a tumor suppressor role for this miRNA. In conclusion, we show global downregulation of 14q32-encoded miRNAs in an in vivo model of PTC progression. The potential circuitry in which these miRNAs are involved suggests that these miRNAs could play a key role in the pathophysiology of PTC and therefore be relevant for the development of new therapeutic strategies.

MicroRNA-26a regulates ANXA1, rather than DAL-1, in the development of lung cancer

The aim of the present study was to investigate the expression and role of microRNA-26a (miR-26a) in lung cancer, and to verify whether differentially expressed in adenocarcinoma of the lung (DAL-1) is the target protein of miR-26a. mRNA expression levels of miR-26a and DAL-1 were detected using reverse transcription-quantitative polymerase chain reaction. Protein expression levels of DAL-1 and annexin A1 (ANXA1) were evaluated by western blot analysis. Cell Counting Kit-8, Transwell and wound scratch healing assays were used to characterize the function of miR-26a in lung cancer cells. The association of DAL-1 with miR-26a or ANXA1 was determined by dual-luciferase reporter or two-dimensional gel electrophoresis assays. miR-26a revealed decreased expression levels in lung cancer tissues compared with normal lung tissues, and decreased expression levels in lung cancer cells compared with 16HBE cells. Inhibition of miR-26a promoted lung cancer cell growth, migration and invasion. The DAL-1 protein exhibited downregulated expression levels in lung cancer tissues. DAL-1 was not the direct target gene of miR-26a. The two-dimensional gel electrophoresis assay confirmed that DAL-1 and ANXA1 were associated proteins. Expression levels of the ANXA1 protein were increased following DAL-1 gene silencing. The altered expression level of miR-26a affected the expression of ANXA1, and not of DAL-1. miR-26a demonstrated decreased expression levels in lung cancer cells, and it has an important effect on the biological function of lung cancer cells. However, DAL-1 was not a target gene of miR-26a. As a DAL-1 associated protein, ANXA1 was regulated by miR-26a.

miRNA expression and function in thyroid carcinomas: a comparative and critical analysis and a model for other cancers

As in many cancer types, miRNA expression profiles and functions have become an important field of research on non-medullary thyroid carcinomas, the most common endocrine cancers. This could lead to the establishment of new diagnostic tests and new cancer therapies. However, different studies showed important variations in their research strategies and results. In addition, the action of miRNAs is poorly considered as a whole because of the use of underlying dogmatic truncated concepts. These lead to discrepancies and limits rarely considered. Recently, this field has been enlarged by new miRNA functional and expression studies. Moreover, studies using next generation sequencing give a new view of general miRNA differential expression profiles of papillary thyroid carcinoma. We analyzed in detail this literature from both physiological and differential expression points of view. Based on explicit examples, we reviewed the progresses but also the discrepancies and limits trying to provide a critical approach of where this literature may lead. We also provide recommendations for future studies. The conclusions of this systematic analysis could be extended to other cancer types.

miR-451a is underexpressed and targets AKT/mTOR pathway in papillary thyroid carcinoma

Papillary Thyroid Carcinoma (PTC) is the most frequent thyroid cancer. Although several PTC-specific miRNA profiles have been reported, only few upregulated miRNAs are broadly recognized, while less consistent data are available about downregulated miRNAs. In this study we investigated miRNA deregulation in PTC by miRNA microarray, analysis of a public dataset from The Cancer Genome Atlas (TCGA), literature review and meta-analysis based on a univocal miRNA identifier derived from miRBase v21. A list of 18 miRNAs differentially expressed between PTC and normal thyroid was identified and validated in the TCGA dataset. Furthermore, we compared our signature with miRNA profiles derived from 15 studies selected from literature. Then, to select possibly functionally relevant miRNA, we integrated our miRNA signature with those from two in vitro cell models based on the PTC-driving oncogene RET/PTC1. Through this strategy, we identified commonly deregulated miRNAs, including miR-451a, which emerged also by our meta-analysis as the most frequently reported downregulated miRNA. We showed that lower expression of miR-451a correlates with aggressive clinical-pathological features of PTC as tall cell variant, advanced stage and extrathyroid extension. In addition, we demonstrated that ectopic expression of miR-451a impairs proliferation and migration of two PTC-derived cell lines, reduces the protein levels of its recognized targets MIF, c-MYC and AKT1 and attenuates AKT/mTOR pathway activation.

Overall, our study provide both an updated overview of miRNA deregulation in PTC and the first functional evidence that miR-451a exerts tumor suppressor functions in this neoplasia.

MicroRNA-146b: A Novel Biomarker and Therapeutic Target for Human Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) is the most common tumor subtype of thyroid cancer. However, not all PTCs are responsive to current surgical and radioiodine treatment. The well-established clinical prognostic factors include tumor size, lymph node/distal metastasis, and extrathyroidal invasion. The RET/PTC-RAS-BRAF linear molecular signaling cascade is known to mediate PTC pathogenesis. However, whether presence of BRAF mutation, the most common genetic alteration in PTC, can affect PTC behavior and prognosis is controversial. MicroRNAs (miRNAs) have been labeled as promising molecular prognostic markers in several tumor types. Our recent studies demonstrated that microRNA-146b (miR-146b) deregulation is associated with PTC aggressiveness and prognosis. Here we summarize the current knowledge related to the functional roles, regulated target genes, and clinical applications of miR-146b in PTC and discuss how these studies provide insights into the key role of miR-146b as an oncogenic regulator promoting cellular transformation as well as a prognosis marker for tumor recurrence in PTC. In conjunction with the current perspectives on miRNAs in a wide variety of human cancers, this review will hopefully translate these updated findings on miR-146b into more comprehensive diagnostic or prognostic information regarding treatment in PTC patients before surgical intervention and follow up strategies.

miR-21a-5p Contributes to Porcine Hemagglutinating Encephalomyelitis Virus Proliferation via Targeting CASK-Interactive Protein1 In vivo and vitro

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurovirulent coronavirus that can cause nervous symptoms in piglets with muscle tremors, hind limb paralysis, and nystagmus. Whether some factors affect virus replication and proliferation had not been fully understood in the course of nerve damage caused by PHEV infection. In recent years, some reports suggested that miRNA might play a key regulatory role in viral infection. In this study, we found the miR-21a-5p is notably up-regulated in the brains of mice and N2a cells infected with PHEV, and it down-regulated the expression of CASK-interactive protein1 (Caskin1) by directly targeting the 3′-UTR of Caskin1 using a Dual-Luciferase reporter assay. The over-expression of miR-21a-5p or Caskin1 knockdown in the host significantly contributes to PHEV proliferation. Conversely, the silencing of miR-21a-5p by miR-21a-5p inhibitors suppressed the virus proliferation. Taken together, our results indicate that Caskin1 is the direct target gene of miR-21a-5p, and it is advantageous to virus proliferation by down-regulating Caskin1. These findings may help in the development of strategies for therapeutic applications.

Establishment of a miRNA-mRNA regulatory network in metastatic renal cell carcinoma and screening of potential therapeutic targets

This study aimed to screen effective diagnosis or treatment biomarkers for renal cell carcinoma, especially for metastatic renal cell carcinoma (mRCC) based on microRNA (miRNA) and messenger RNA (mRNA) genechip, and their regulatory network. The differential expressions of miRNAs and mRNAs were examined by miRNA and mRNA gene-chip analyses, respectively, in patients with either localized renal cell carcinoma (lRCC) or mRCC, and a miRNA-mRNA regulatory network was established. Subsequently, the regulation of selected mRNAs by miRNAs was validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and dual-luciferase reporter gene assay. Thirty-one up-regulated miRNAs, 196 down-regulated miRNAs, 214 up-regulated mRNAs, and 156 down-regulated mRNAs were identified in patients with mRCC. In total, 1315 miRNA-mRNA pairs, involving 34 miRNAs and 225 mRNAs, were established. The expression profiles of four up-regulated miRNAs, hsa-miR-139-5p, hsa-miR-140-3p, hsa-miR-151a-3p, and hsa-miR-204-5p, and four down-regulated miRNAs, hsa-miR-409-3p, hsa-miR-671-3p, hsa-miR-1203, and hsa-miR-1290, were consistent with the results from the miRNA gene-chip analysis. The expression profiles of NEU2, MASP1, MCL1, ARHGAP11A, HOXA1, and CLDN8 were consistent with the results from the mRNA gene-chip analysis. In vitro, hsa-miR-140-3p bound to the 3' untranslated region (3'-UTR) of the MASP1 mRNA and down-regulated its expression. Similarly, hsa-miR-151a-3p, hsa-miR-671-3p, and hsa-miR-1290 bound to the 3'-UTRs of the MCL1, HOXA1, and HOXA1 mRNAs, respectively, and down-regulated their expressions. However, binding by hsa-miR-140-3p, hsa-miR-671-3p, or hsa-miR-1290 did not down-regulate the expressions of NEU2, ARHGAP11A, and CLDN8, respectively. This study provides a significant reference of investigating the pathogenesis of mRCC and the subsequent screening of potential therapeutic targets.

Cancer stem cells as a potential therapeutic target in thyroid carcinoma

A number of studies have indicated that tumor growth and proliferation is dependent on a small subset of cells, defined as cancer stem cells (CSCs). CSCs have the capability to self-renew, and are involved with cancer propagation, relapse and metastatic dissemination. CSCs have been isolated from numerous tissues, including normal and cancerous thyroid tissue. A regulatory network of signaling pathways and microRNAs (miRNAs) control the properties of CSCs. Differentiated thyroid carcinoma is the most common type of endocrine cancer, with an increasing incidence. Anaplastic thyroid carcinoma is the most rare type of endocrine cancer; however, it also exhibits the highest mortality rate among thyroid malignancies, with an extremely short survival time. Thyroid CSCs are invasive and highly resistant to conventional therapies, including radiotherapy and chemotherapy, which results in disease relapse even when the primary lesion has been eradicated. Therefore, targeting thyroid CSCs may represent an effective treatment strategy against aggressive neoplasms, including recurrent and radioresistant tumors. The present review summarizes the current literature regarding thyroid CSCs and discusses therapeutic strategies that target these cells, with a focus on the function of self-renewal pathways and miRNAs. Elucidation of the mechanisms that regulate CSC growth and survival may improve novel therapeutic approaches for treatment-resistant thyroid cancers.

Candidate microRNAs as biomarkers of thyroid carcinoma: a systematic review, meta-analysis, and experimental validation

Thyroid cancer is one of the most common carcinomas of the endocrine system with an increasing incidence. A growing number of studies have focused on the diagnostic and prognostic values of dysregulated microRNAs (miRNAs) in thyroid carcinoma. However, differences in the measurement platforms, variations in lab protocols, and small sample sizes can make gene profiling data incomparable. A meta-review of the published studies that compared miRNA expression data of thyroid carcinoma and paired normal tissues was performed to identify potential miRNA biomarkers of thyroid carcinoma with the vote-counting strategy. Two hundred and thirty-six aberrantly expressed miRNAs were reported in 19 microRNA expression profiling studies. Among them, 138 miRNAs were reported in at least two studies. We also provided a meta-signature of differentially expressed miRNAs between individual histological types of thyroid carcinoma and normal tissues. The experimental validation with qRT-PCR analysis verified that the profiles identified with the meta-review approach could effectively discriminate papillary thyroid carcinoma tissues from paired noncancer tissues. The meta-review of miRNA expression profiling studies of thyroid carcinoma would provide information on candidate miRNAs that could potentially be used as biomarkers in thyroid carcinoma.

Analysis of Serum microRNA Profile by Solexa Sequencing in Women With Endometriosis

OBJECTIVES

The potential roles of serum microRNAs (miRNAs), as biomarkers, in noninvasive diagnosis of endometriosis have been reported by microarray analysis. However, microarray analysis cannot perform well in outcome accuracy and repeatability and is not suitable to be used for exploring new targets. Here, Solexa sequencing, a wide and precise method, was adopted to further analyze the serum miRNAs profile in endometriosis, which may offer more evidence to apply serum miRNAs as biomarkers in diagnosis of endometriosis.

MATERIALS AND METHODS

Serum samples were collected from 30 patients with minimal-mild endometriosis and 20 women without endometriosis as control. Expression of serum miRNAs was measured by Solexa sequencing and validated by quantitative real-time polymerase chain reaction (qPCR).

RESULTS

Solexa sequencing showed 93.63% clean readouts for all small RNAs in the serum of patients with endometriosis and controls. A total of 108 miRNAs were found to be differentially expressed in the serum of patients with endometriosis by deep sequencing, compared to controls. Among them, 98 miRNAs were significantly downregulated, while 10 miRNAs were significantly upregulated. Only 21 of 98 significantly downregulated miRNAs, and none of significantly upregulated miRNAs were reported in published literatures, which may be due to the differences in samples and analytical methods. The Solexa sequencing results were consequently validated by qPCR in additional samples. Some miRNAs were identified to be promising diagnostic markers of endometriosis. The functional annotation of target genes revealed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that a majority of differential miRNAs might be involved in endometriosis.

CONCLUSION

Circulating miRNAs may be useful as detection biomarkers for the early diagnosis of minimal-mild endometriosis.

Differences in miRNA and mRNA Profile of Papillary Thyroid Cancer Variants

Papillary thyroid cancer (PTC) can be divided into classical variant of PTC (cPTC), follicular variant of PTC (fvPTC), and tall cell variant (tcPTC). These variants differ in their histopathology and cytology; however, their molecular background is not clearly understood. Our results shed some new light on papillary thyroid cancer biology as new direct miRNA-gene regulations are discovered. The Cancer Genome Atlas (TCGA) 466 thyroid cancer samples were studied in parallel datasets to discover potential miRNA-mRNA regulations. Additionally, miRNAs and genes differentiating PTC variants (cPTC, fvPTC, and tcPTC) were indicated. Putative miRNA regulatory pairs were discovered: hsa-miR-146b-5p with PHKB and IRAK1, hsa-miR-874-3p with ITGB4 characteristic for classic PTC samples, and hsa-miR-152-3p with TGFA characteristic for follicular variant PTC samples. MiRNA-mRNA regulations discovery opens a new perspective in understanding of PTC biology. Furthermore, our successful pipeline of miRNA-mRNA regulatory pathways discovery could serve as a universal tool to find new miRNA-mRNA regulations, also in different datasets.

Clinical pathological impacts of microRNAs in papillary thyroid carcinoma: A crucial review

MicroRNAs (miRNA) deregulation is an important event in the pathogenesis of papillary thyroid carcinoma. The alternations of miRNAs could be measured at the cancer tissue or serum so that the clinical impacts of them in papillary thyroid carcinoma could be studied. Using the approach, miRNA deregulation was reported to be associated with pathological stages in papillary thyroid carcinoma as reflected by the differences in extent of extra-thyroidal invasion, size of the tumour as well as presence of lymph nodes metastases. The most common miRNAs involved in these processes are miRNA-146, miRNA-222 and miRNA-221. Also, miRNA-222 and miRNA-146b deregulation are commonly associated with cancer recurrence in patients with papillary thyroid carcinoma. Additionally, miRNA-146, miRNA-222, and miRNA-221 are the top-regulated miRNAs involved in the pathogenesis confirmed by deep-sequencing and have their function studied in vitro. Targeting these subsets of miRNAs may be useful in management of patients with papillary thyroid carcinoma.

miR-584 Suppresses Invasion and Cell Migration of Thyroid Carcinoma by Regulating the Target Oncogene ROCK1

BACKGROUND

Uncovering the target gene of miR-584 to control thyroid carcinoma (TC) invasion and migration is of central importance in the diagnosis, treatment, and prognosis of TC. To validate whether miR-584 has a tumor-suppressive role in thyroid cancer cells by targeting ROCK1, a series of experiments were conducted to figure out the mechanism of action of miR-584.

MATERIAL AND METHODS

Migration analyses and cell proliferation assays were performed using miR-584-transfected cells. The expression levels of miR-584 in TC were detected by using real-time polymerase chain reaction (PCR). Western blot analyses were conducted to find out the relationship between the tumor suppressor miR-584 and the target oncogene ROCK1 protein expression levels. Wound healing experiments were used to examine the relationships between miR-584 and the migration of thyroid cancer K1 cells and the effects of ROCK1 knockdown on K1 cell motility.

RESULTS

Our results demonstrate that altering the miR-584 levels affects human thyroid cancer cell migration, but has no effect on cell proliferation. The relative ROCK-1 expression levels were 1 and 0.54 in the scrambled-sequence control group and the miR-584 group, respectively. K1 cells transfected with siRNA-ROCK-1 showed weaker cell migration than cells transfected with siRNA-NC (negative control); the cell motility ratios were 18% and 27%, respectively.

CONCLUSION

These results indicate that miR-584 could inhibit the expression of ROCK1, and ROCK1 knockdown would further affect the migration ability of K1 cells.

Circulating miR-25-3p and miR-451a May Be Potential Biomarkers for the Diagnosis of Papillary Thyroid Carcinoma

OBJECTIVE

There is no effective and reliable biomarker to distinguish benign thyroid nodules from papillary thyroid carcinomas (PTC). This study aimed at examining the levels of plasma miRNAs in patients with PTC or benign nodules to explore the potential miRNA biomarkers for PTC.

PATIENTS AND METHODS

Genome-wide plasma miRNA expression profiles were determined by the miRNA Microarray and the significantly higher levels of miRNAs were validated in plasma and tissues by quantitative RT-PCR. The levels of two miRNAs were further tested in seven patients before and after tumor excision and the potential values for the diagnosis of PTC were evaluated by receiver operating characteristic curve (ROC).

RESULTS

In comparison with that in the patients with benign nodules, eight significantly higher and three lower levels of plasma miRNAs were detected in the PTC patients. Further validation indicated that the levels of plasma miR-25-3p, miR-451a, miR-140-3p and let-7i were significantly higher in the PTC cases than in those with benign nodules or the healthy controls. Significantly higher levels of miR-25-3p and miR-451a were detected in the thyroid tissues from the PTC patients. The levels of plasma miR-25-3p and miR-451a in seven patients significantly decreased after tumor excision. ROC analyses revealed that the levels of plasma miR-25-3p at cut-off 1.41 and miR-451a at 1.38 had sensitivity of 92.8% and 88.9%, and specificity of 68.8% and 66.7% for distinguishing PTC from benign nodules, respectively.

CONCLUSION

Our findings suggest that the levels of plasma miR-25-3p and miR-451a may be valuable for the diagnosis of PTC.

In Situ Hybridization Analysis of miR-146b-5p and miR-21 in Thyroid Nodules: Diagnostic Implications

Some thyroid nodules such as follicular adenomas (FAs), follicular variant of papillary thyroid carcinomas (FVPTCs), and follicular thyroid carcinomas (FTCs) exhibit similar clinical presentations and gross morphologic appearances. The differential diagnosis of these lesions is sometimes difficult based on morphologic, cytologic, or clinical features alone. miR-146b-5p and miR-21 deregulation has been associated with progression and metastasis of thyroid cancers. However, the utility of in situ hybridization (ISH) to determine the cellular localization, diagnostic, and prognostic significance of miR-146b-5p and miR-21 expression in thyroid tumors has not been extensively analyzed. In order to examine the expression of miR-146b-5p and miR-21 in benign and malignant thyroid tissues and to determine if these microRNAs could be assigned to distinct histomorphological types of thyroid nodules, we analyzed miR-146b-5p and miR-21 expression in thyroid nodules on tissue microarrays (TMAs) with 193 thyroid specimens by ISH. miR-146b-5p and miR-21 expression in thyroid tissues was also analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). miR-146b-5p was highly expressed (89%) in papillary thyroid carcinomas (PTCs) and 41% of FVPTC. The expression of miR-146b-5p was not expressed in most FTCs, anaplastic thyroid carcinomas (ATCs), poorly differentiated thyroid carcinomas (PDTCs), or FAs (7, 8, 0, and 0%, respectively). MiR-21 was overexpressed in 83% of ATCs, 79 % of PTCs, 34% of FVPTCs, and 19% of PDTCs. The expression of miR-21 was not expressed in most FAs (9%) or FTCs (4%). Normal thyroid tissues and most benign goiters were negative for miR-146b-5p and miR-21. qRT-PCR analysis supported the ISH findings. PTC cases with positive expression of miR-146b-5p and miR-21 had significantly poorer disease-free survival rates. Immunohistochemical staining for HBME-1 showed positive staining in PTCs (100 %) and FVPTCs (92 %) with a subset of FTC (40%) staining positive, while all FAs were negative. Since miR-146b-5p was mainly expressed in PTC including FVPTC and was not expressed in most FTC, PDTC, or ATC, it may serve as a useful diagnostic marker for PTC. ISH is a useful method to analyze microRNA expression in formalin-fixed paraffin-embedded thyroid tissues.

MicroRNA-181c targets Bcl-2 and regulates mitochondrial morphology in myocardial cells

Apoptosis is an important mechanism for the development of heart failure. Mitochondria are central to the execution of apoptosis in the intrinsic pathway. The main regulator of mitochondrial pathway of apoptosis is Bcl-2 family which includes pro- and anti-apoptotic proteins. MicroRNAs are small noncoding RNA molecules that regulate gene expression by inhibiting mRNA translation and/or inducing mRNA degradation. It has been proposed that microRNAs play critical roles in the cardiovascular physiology and pathogenesis of cardiovascular diseases. Our previous study has found that microRNA-181c, a miRNA expressed in the myocardial cells, plays an important role in the development of heart failure. With bioinformatics analysis, we predicted that miR-181c could target the 3' untranslated region of Bcl-2, one of the anti-apoptotic members of the Bcl-2 family. Thus, we have suggested that miR-181c was involved in regulation of Bcl-2. In this study, we investigated this hypothesis using the Dual-Luciferase Reporter Assay System. Cultured myocardial cells were transfected with the mimic or inhibitor of miR-181c. We found that the level of miR-181c was inversely correlated with the Bcl-2 protein level and that transfection of myocardial cells with the mimic or inhibitor of miR-181c resulted in significant changes in the levels of caspases, Bcl-2 and cytochrome C in these cells. The increased level of Bcl-2 caused by the decrease in miR-181c protected mitochondrial morphology from the tumour necrosis factor alpha-induced apoptosis.

Differential expression profiling of microRNAs in para-carcinoma, carcinoma and relapse human pancreatic cancer

PURPOSE

To explore the altered different expression of miRNAs and the mechanisms underlying the relapse and metastasis of pancreatic cancer.

MATERIALS AND METHODS

The most differentially expressed miRNAs were analyzed by gene ontology (GO) term analysis, Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis and protein interaction analysis. The potentially regulated target genes of the most differentially expressed miRNAs were also analyzed further by GO term analysis and KEGG pathway analysis, and quantitated by qRT-PCR.

RESULTS

In total, we found 12 miRNAs displayed at least a 30-fold increase or decrease in expression of carcinoma and relapse vs. para-carcinoma human pancreatic cancer (C/R vs. P). In addition, our study found that pancreatic cancer was related to pathways in cancer, including Jak-STAT signaling pathway, MAPK signaling pathway and PPAR signaling pathway.

CONCLUSIONS

The differential expressed miRNAs and their predicted target genes that involved in Jak-STAT signaling pathway, MAPK signaling pathway and PPAR signaling pathway indicating their potential roles in pancreatic carcinogenesis and progress.

The analysis of microRNA-34 family expression in human cancer studies comparing cancer tissues with corresponding pericarcinous tissues

Recently many studies have focused on the microRNA-34 (miR-34) family expression in various cancers; nevertheless, the controversial results of these studies still exist in identifying miR-34 members as new biomarkers of cancers. Therefore, we carried out this comprehensive meta-analysis of published studies that compared the miR-34 family expression profiles between cancer tissues and paired neighboring noncancerous tissues to systemically evaluate the findings globally and address the inconsistencies of pertinent literatures. The data included in this article were collected from Embase, PubMed and Web of Science up to December 2013. To overcome the difficulties that many raw data were unavailable and study methods were different, a vote-counting strategy was adopted to identify consistent markers in our analysis. Ultimately, a total of 23 cancers were reported in the 61 eligible studies, of which 46 studies provided fold-change value information. In the consistently reported cancer types, non-small cell lung cancer (NSCLC), glioma and nasopharyngeal carcinoma (NPC) ranked at the top with down-regulated feature. Cervical neoplasm was consistently reported to be over-expressed in the panel of each member of miR-34s. Subgroup analysis of miR-34 family expression demonstrated that colorectal cancer (CRC), gastric cancer (GC), hepatocellular carcinoma (HCC) and prostate cancer (PCa) were most frequently reported with inconsistent regulations. Our meta-analysis showed that miR-34 family members could be expected to become potential diagnostic and prognostic biomarkers in some types of human cancers. Further well-designed and larger sample studies are surely warranted to identify the role of the miR-34 family in the occurrence and development of tumors.

Expression profile and clinical significance of microRNAs in papillary thyroid carcinoma

This study screened microRNAs (miRNAs) that are abnormally expressed in papillary thyroid carcinoma (PTC) tissues to identify PTC and nodular goiter and the degree of PTC malignancy. A total of 51 thyroid tumor tissue specimens paired with adjacent normal thyroid tissues were obtained from the Department of Surgical Oncology of Hangzhou First People’s Hospital from June-December 2011. miRNA expression profiles were examined by microarrays and validated by quantitative real-time PCR (qRT-PCR). Expression levels of the miRNAs were analyzed to assess if they were associated with selected clinicopathological features. Eleven miRNAs were significantly differentially expressed between nodular goiter and PTC and between highly invasive and low invasive PTC. miR-199b-5p and miR-30a-3p were significantly differentially expressed among the three groups. miR-30a-3p, miR-122-5p, miR-136-5p, miR-146b-5p and miR-199b-5p were selected for further study by qRT-PCR and miR-146b-5p, miR-199b-5p and miR-30a-3p were different between the PTC and nodular goiter groups. miR-199b-5p was over-expressed in PTC patients with extrathyroidal invasion and cervical lymph node metastasis. In conclusion miR-146b-5p, miR-30a-3p, and miR-199b-5p may serve as biomarkers for the diagnosis of PTC and miR-199b-5p is associated with PTC invasiveness.

Differentially expressed miRNAs in cancer-stem-like cells: markers for tumor cell aggressiveness of pancreatic cancer

Pancreatic cancer (PC) is one of the most deadly cancers. The higher mortality is in part due to treatment resistance and early onset of metastasis. The existence of cancer-stem-like cells (CSLCs) has been widely accepted to be responsible for tumor aggressiveness in PC. Emerging evidence suggests that CSLCs have the capacity for increased cell growth, cell migration/invasion, metastasis, and treatment resistance, which leads to poor clinical outcome. However, the molecular role of CSLCs in tumor development and progression is poorly understood. Therefore, mechanistic understanding, and targeted killing of CSLCs may provide a newer therapeutic strategy for the treatment of PC. It has been well accepted that microRNAs (miRNAs) play critical roles during tumor development and progression through deregulation of multiple genes. Moreover, deregulated expression of miRNAs may also play a key role in the regulation of CSLC characteristics and functions. Here we show that isolated CD44(+)/CD133(+)/EpCAM(+) cells (triple-marker-positive cells) from human PC cell lines, MiaPaCa-2 and L3.6pl cells, display aggressive characteristics, such as increased cell growth, clonogenicity, cell migration, and self-renewal capacity, which is consistent with overexpression of CSLC signatures/markers. We also found deregulated expression of over 400 miRNAs, including let-7, miR-30, miR-125b, and miR-335, in CSLCs. As a proof-of-concept, knockdown of miR-125b resulted in the inhibition of tumor cell aggressiveness of CSLCs (triple-marker-positive cells), consistent with the downregulation of CD44, EpCAM, EZH2, and snail. These results clearly suggest the importance of miRNAs in the regulation of CSLC characteristics, and may serve as novel targets for therapy.

Noncoding RNAs in endocrine malignancy

Only recently has it been uncovered that the mammalian transcriptome includes a large number of noncoding RNAs (ncRNAs) that play a variety of important regulatory roles in gene expression and other biological processes. Among numerous kinds of ncRNAs, short noncoding RNAs, such as microRNAs, have been extensively investigated with regard to their biogenesis, function, and importance in carcinogenesis. Long noncoding RNAs (lncRNAs) have only recently been implicated in playing a key regulatory role in cancer biology. The deregulation of ncRNAs has been demonstrated to have important roles in the regulation and progression of cancer development. In this review, we describe the roles of both short noncoding RNAs (including microRNAs, small nuclear RNAs, and piwi-interacting RNAs) and lncRNAs in carcinogenesis and outline the possible underlying genetic mechanisms, with particular emphasis on clinical applications. The focus of our review includes studies from the literature on ncRNAs in traditional endocrine-related cancers, including thyroid, parathyroid, adrenal gland, and gastrointestinal neuroendocrine malignancies. The current and potential future applications of ncRNAs in clinical cancer research is also discussed, with emphasis on diagnosis and future treatment.

MicroRNA-21 regulates biological behaviors in papillary thyroid carcinoma by targeting programmed cell death 4

BACKGROUND

Our recent study has found that microRNA-21 (miRNA-21) was significantly upregulated in papillary thyroid carcinoma (PTC) tissues compared with nontumor tissues by using miRNA microarray chip. However, the function of miRNA-21 is unknown in PTC. The aim of this study was to investigate the roles of miRNA-21 in PTC and the mechanism of gene regulation by it.

METHODS

We transfected PTC cell line (TPC-1) with pEZX-eGFP-miRNA-21 plasmid to determine the biological functions of miRNA-21. Western blot assay was applied to investigate the correlation between miRNA-21 and programmed cell death 4 (PDCD4) expression in TPC-1 cell line.

RESULTS

Overexpression of miRNA-21 could significantly enhance proliferation and invasion and inhibit the apoptosis of TPC-1 cells. In addition, miRNA-21 and PDCD4 expression showed a significantly negative correlation in TPC-1 cells.

CONCLUSIONS

These data suggest that miRNA-21 may play an oncogenic role by directly targeting PDCD4 in the cellular processes of PTC. In addition, the findings in our present study also may represent new clues for the diagnostic and therapeutic strategies in the treatment of PTC.

MicroRNA expression profiling and functional annotation analysis of their targets in patients with type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) results from an autoimmune attack against the insulin-producing pancreatic β-cells, leading to elimination of insulin production. The exact cause of this disorder is still unclear. Although the differential expression of microRNAs (miRNAs), small non-coding RNAs that control gene expression in a post-transcriptional manner, has been identified in many diseases, including T1DM, only scarce information exists concerning miRNA expression profile in T1DM. Thus, we employed the microarray technology to examine the miRNA expression profiles displayed by peripheral blood mononuclear cells (PBMCs) from T1DM patients compared with healthy subjects. Total RNA extracted from PBMCs from 11 T1DM patients and nine healthy subjects was hybridized onto Agilent human miRNA microarray slides (V3), 8x15K, and expression data were analyzed on R statistical environment. After applying the rank products statistical test, the receiver-operating characteristic (ROC) curves were generated and the areas under the ROC curves (AUC) were calculated. To examine the functions of the differentially expressed (p-value<0.01, percentage of false-positives <0.05) miRNAs that passed the AUC cutoff value ≥ 0.90, the database miRWalk was used to predict their potential targets, which were afterwards submitted to the functional annotation tool provided by the Database for Annotation, Visualization, and Integrated Discovery (DAVID), version 6.7, using annotations from the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. We found 57 probes, corresponding to 44 different miRNAs (35 up-regulated and 9 down-regulated), that were differentially expressed in T1DM and passed the AUC threshold of 0.90. The hierarchical clustering analysis indicated the discriminatory power of those miRNAs, since they were able to clearly distinguish T1DM patients from healthy individuals. Target prediction indicated that 47 candidate genes for T1DM are potentially regulated by the differentially expressed miRNAs. After performing functional annotation analysis of the predicted targets, we observed 22 and 12 annotated KEGG pathways for the induced and repressed miRNAs, respectively. Interestingly, many pathways were enriched for the targets of both up- and down-regulated miRNAs and the majority of those pathways have been previously associated with T1DM, including many cancer-related pathways. In conclusion, our study indicated miRNAs that may be potential biomarkers of T1DM as well as provided new insights into the molecular mechanisms involved in this disorder.

MicroRNA transcriptome in swine small intestine during weaning stress

MicroRNAs (miRNAs) play important roles in intestinal diseases; however, the role of miRNAs during weaning stress is unknown. In our study, six jejunal small RNA libraries constructed from weaning piglets at 1, 4 and 7 d after weaning (libraries W1, W4 and W7, respectively) and from suckling piglets on the same days as the weaning piglets (libraries S1, S4 and S7, respectively) were sequenced using Solexa high-throughput sequencing technology. Overall, 260 known swine miRNAs and 317 novel candidate miRNA precursors were detected in the six libraries. The results revealed that 16 differentially expressed miRNAs were found between W1 and S1; 98 differentially expressed miRNAs were found between W4 and S4 (ssc-mir-146b had the largest difference); and 22 differentially expressed miRNAs were found between W7 and S7. Sequencing miRNA results were validated using RT-qPCR. Approximately 11,572 miRNA-mRNA interactions corresponding to 3,979 target genes were predicted. The biological analysis further describe that the differentially expressed miRNAs regulated small intestinal metabolisms, stressful responses and immune functions in piglets. Therefore, the small intestine miRNA transcriptome was significantly different between weaning and suckling piglets; the difference varied with the number of days after weaning.