Prognostic value of a two-microRNA signature for papillary thyroid cancer and a bioinformatic analysis of their possible functions

Circular RNA eukaryotic translation initiation factor 6 facilitates TPC-1 cell proliferation and invasion through the microRNA-138-5p/lipase H axis

Both circular RNA eukaryotic translation initiation factor 6 (circEIF6) and microRNA (miR)-138-5p participate in thyroid cancer (TC) progression. Nevertheless, the relationship between them remains under-explored. Hence, this research ascertained the mechanism of circEIF6 in TC via miR-138-5p. After TC tissues and cells were harvested, circEIF6, miR-138-5p, and lipase H (LIPH) levels were assessed. The binding relationships among circEIF6, miR-138-5p, and LIPH were analyzed. The impacts of circEIF6, miR-138-5p, and LIPH on the invasive and proliferative abilities of TPC-1 cells were examined by Transwell and EdU assays. Tumor xenograft in nude mice was established for in vivo validation of the impact of circEIF6. CircEIF6 expression was high in TC cells and tissues. Additionally, miR-138-5p was poor and LIPH level was high in TC tissues. Mechanistically, circEIF6 competitively bound to miR-138-5p to elevate LIPH via a competitive endogenous RNA mechanism. Silencing of circEIF6 reduced TPC-1 cell proliferative and invasive properties, which was annulled by further inhibiting miR-138-5p or overexpressing LIPH. Likewise, circEIF6 silencing repressed the growth of transplanted tumors, augmented miR-138-5p expression, and diminished LIPH expression in nude mice. Conclusively, circEIF6 silencing reduced LIPH level by competitive binding to miR-138-5p, thus subduing the proliferation and invasion of TPC-1 cells.

BRAF, TERT and HLA-G Status in the Papillary Thyroid Carcinoma: A Clinicopathological Association Study

As BRAF, TERT, HLA-G, and microRNAs have been individually associated with papillary thyroid carcinoma (PTC), we aimed to evaluate the individual and collaborative role of these markers in PTC in the same patient cohort. HLA-G and BRAF tumor expression was evaluated by immunohistochemistry. Using molecular methods, BRAFV600E and TERT promoter mutations were evaluated in thyroid fine needle aspirates. MicroRNA tumor profiling was investigated using massively parallel sequencing. We observed strong HLA-G (67.96%) while BRAF (62.43%) staining was observed in PTC specimens. BRAF overexpression was associated with poor response to therapy. The BRAFV600E (52.9%) and TERTC228T (13%) mutations were associated with extrathyroidal extension, advanced-age, and advanced-stage cancer. The TERT rs2853669 CC+TC genotypes (38%) were overrepresented in metastatic tumors. Nine modulated microRNAs targeting the BRAF, TERT, and/or HLA-G genes were observed in PTC and involved with cancer-related signaling pathways. The markers were individually associated with PTC features, emphasizing the synergistic effect of BRAFV600E and TERTC228T; however, their collaborative role on PTC outcome was not fully demonstrated. The differentially expressed miRNAs targeting the BRAF and/or HLA-G genes may explain their increased expression in the tumor milieu.

Identification of a four-miRNA signature predicts the prognosis of papillary thyroid cancer

BACKGROUND

In recently diagnosed patients with thyroid cancer, papillary thyroid cancer (PTC), as the most common histological subtype, accounts for 90% of all cases. Although PTC is known as a relatively adolescent malignant disease, there still is a high possibility of recurrence in PTC patients with a poor prognosis. Therefore, new biomarkers are necessary to guide more effective stratification of PTC patients and personalize therapy to avoid overtreatment or inadequate treatment. Accumulating evidence demonstrates that microRNAs (miRNAs) have broad application prospects as diagnostic biomarkers in cancer.

AIM

To explore novel markers consisting of miRNA-associated signatures for PTC prognostication.

METHODS

We obtained and analyzed the data of 497 PTC patients from The Cancer Genome Atlas. The patients were randomly assigned to either a training or testing cohort.

RESULTS

We discovered 237 differentially expressed miRNAs in tumorous thyroid tissues compared with normal tissues, which contained 172 up-regulated and 65 down-regulated miRNAs. The evaluation of differently expressed miRNAs was conducted using our risk score model. We then successfully generated a four-miRNA potential prognostic signature [risk score = (-0.001 × hsa-miR-181a-2-3p) + (0.003 × hsa-miR-138-5p) + (-0.018 × hsa-miR-424-3p) + (0.284 × hsa-miR-612)], which reliably distinguished patients from high and low risk with a significant difference in the overall survival (P < 0.01) and was effective in predicting the five-year disease survival rate with the area under the receiver operating characteristic curve of 0.937 and 0.812 in the training and testing cohorts, respectively. Additionally, there was a trend indicated that high-risk patients had shorter relapse-free survival, although statistical significance was not reached (P = 0.082) in our sequencing cohort.

CONCLUSION

Our results indicated a four-miRNA signature that has a robust predictive effect on the prognosis of PTC. Accordingly, we would recommend more radical therapy and closer follow-ups for high-risk groups.

microRNA-181a promotes the oncogene S100A2 and enhances papillary thyroid carcinoma growth by mediating the expression of histone demethylase KDM5C

BACKGROUND AND PURPOSE

Papillary thyroid carcinoma (PTC) is an endocrine malignancy. Increasing evidence highlights microRNAs (miRNAs) as important participants in PTC. Here, we investigated the role of miR-181a in PTC.

METHODS

A microarray-based analysis was performed to identify the differential expression of miR-181a in PTC, which was validated with RT-qPCR. Protein expression of the proliferation-related factor Ki-67 and apoptosis- and migration-related factors in PTC was assessed with immunoblot analysis. A dual-luciferase reporter gene assay was adopted to verify the relationship between miR-181a and lysine demethylase 5C (KDM5C). Chromatin immunoprecipitation (ChIP) was used to detect the level of the H3K4me3 modification on S100 calcium-binding protein A2 (S100A2). Cell viability, apoptosis, and invasion and migration abilities were evaluated by Cell Counting Kit-8 (CCK-8), flow cytometry, and transwell assays, respectively. The in vitro results were verified in in vivo nude mouse models.

RESULTS

miR-181a was highly expressed in PTC tissues and cell lines. Silencing miR-181a repressed the proliferation and migration of PTC cells. KDM5C was identified as the target gene of miR-181a and represses S100A2 expression through histone demethylation to diminish the migration and proliferation of PTC cells. miR-181a depletion suppressed tumor growth.

CONCLUSION

Collectively, these results suggest that highly expressed miR-181a promotes the proliferation of PTC cells by increasing the expression of the oncogene S100A2. This study contributes to the advancement of miR-181a-targeted therapeutics.

Low expression of TFF3 in papillary thyroid carcinoma may correlate with poor prognosis but high immune cell infiltration

Background: Papillary thyroid carcinoma (PTC) is one of the most common endocrine malignancies and has a favorable prognosis. However, optimal treatments and prognostic markers have not been clearly identified. Methods: Gene expression data from primary PTC were downloaded from the Gene Expression Omnibus database and subjected to two analyses of differentially expressed genes (DEGs), followed by intersecting individual and integrated DEGs analyses as well as gene set enrichment analysis. Analysis of data from Sequence Read Archive and The Cancer Genome Atlas, immunohistochemistry and qRT-PCR of TFF3 were performed to validate the results. Finally, the relationship between gene expression and disease-free survival as well as immune cell infiltration were investigated. Results: Six critical DEGs and several tumor-enriched signaling pathways were identified. Immunohistochemistry and qRT-PCR validated the low expression of TFF3 in PTC. TFF3 and FCGBP are coexpressed in PTC, and patients with lower gene expression had worse disease-free survival but higher immune cell infiltration. Conclusion: TFF3 was significantly underexpressed and may function with FCGBP synergistically in PTC.

miR-181a-2-3p Stimulates Gastric Cancer Progression via Targeting MYLK

Background: The abnormal expression of miRNAs facilitates tumorigenesis and development. miR-181a-2-3p is up-regulated in various cancers, yet its mechanism in gastric cancer (GC) remains elusive.

Objective: To understand mechanism of miR-181a-2-3p stimulating GC cell progression via targeting Myosin Light Chain Kinase (MYLK) expression.

Methods: Downstream genes of miRNA of interest were predicted in TargetScan and miRTarBase. qRT-PCR and western blot were applied to assess miR-181a-2-3p and MYLK expression in GC cells and normal cells. Dual-luciferase and RIP assays were completed to assess binding of miR-181a-2-3p and MYLK. Cell Counting Kit-8 (CCK-8) assay was conducted for detecting viability of AGS and SNU-1 cells, while Transwell tested migratory and invasive abilities of cells. Nude mouse transplantation tumor experiment was performed to assay tumor growth in vivo.

Results: miR-181a-2-3p was notably increased in human GC cell lines, while MYLK was remarkably down-regulated. RIP and dual-luciferase assay disclosed that miR-181a-2-3p targeted MYLK and repressed MYLK. Forced miR-181a-2-3p expression fostered GC cell proliferation, invasion, migration, and fostered tumor growth in vivo. Promoting effect of miR-181a-2-3p on GC cells was reversed when miR-181a-2-3p and MYLK were simultaneously overexpressed.

Conclusion: miR-181a-2-3p facilitated GC cell progression by targeting MYLK, and it may be a pivotal prognostic biomarker in investigating molecular mechanism of GC.

A 6 transcription factors-associated nomogram predicts the recurrence-free survival of thyroid papillary carcinoma

Various researches demonstrated that transcription factors (TFs) played a crucial role in the progression and prognosis of cancer. However, few studies indicated that TFs were independent biomarkers for the prognosis of thyroid papillary carcinoma (TPC). Our aim was to establish and validate a novel TF signature for the prediction of TPC patients' recurrence-free survival (RFS) from The Cancer Genome Atlas (TCGA) database to improve the prediction of survival in TPC patients.The genes expression data and corresponding clinical information for TPC were obtained from TCGA database. In total, 722 TFs and 545 TPC patients with eligible clinical information were determined to build a novel TF signature. All TFs were included in a univariate Cox regression model. Then, the least absolute shrinkage and selection operator Cox regression model was employed to identify candidate TFs relevant to TPC patients' RFS. Finally, multivariate Cox regression was conducted via the candidate TFs for the selection of the TF signatures in the RFS assessment of TPC patients.We identified 6 TFs that were related to TPC patients' RFS. Receiver operating characteristic analysis was performed in training, validation, and whole datasets, we verified the high capacity of the 6-TF panel for predicting TPC patients' RFS (AUC at 1, 3, and 5 years were 0.880, 0.934, and 0.868, respectively, in training dataset; 0.760, 0.737, and 0.726, respectively, in validation dataset; and 0.777, 0.776, and 0.761, respectively, in entire dataset). The result of Kaplan-Meier analysis suggested that the TPC patients with low scores had longer RFS than the TPC patients with high score (P = .003). A similar outcome was displayed in the validation dataset (P = .001) and the entire dataset (P = 2e-05). In addition, a nomogram was conducted through risk score, cancer status, C-index, receiver operating characteristic, and the calibration plots analysis implied good value and clinical utility of the nomogram.We constructed and validated a novel 6-TF signature-based nomogram for predicting the RFS of TPC patients.

miR-1301-3p suppresses tumor growth by downregulating PCNA in thyroid papillary cancer

OBJECTIVE

Thyroid carcinoma is the most common endocrine tumor, and thyroid papillary carcinoma is the most common form. Although thyroid papillary carcinoma presents a good prognosis, some patients still exhibit recurrence or distant metastasis. miR-1301-3p has been found involved in the occurrence and development of some special tumors. Our study aims to investigate the miR-1301-3p expression in thyroid papillary carcinoma, to explore its biological function, and to provide a potential marker for diagnosis and treatment of thyroid papillary carcinoma.

MATERIALS AND METHODS

The tissue samples from 70 patients with PTC (n = 35) and benign tumors (n = 35) were collected respectively. miR-1301-3p expression were detected by qPCR. Diagnostic value of miR-1301-3p was analyzed by ROC curve. CCK-8 assays and flow cytometry were performed to detect the effect of miR-1301-3p on TPC-1 function. PCNA expression of protein was detected by WB.

RESULTS

Compared with the normal group, the expression of miR-1301-3p was obviously decreased in both benign group and PTC group. With the higher T and N grades, the lower expression of miR-1301-3p. ROC curve analysis showed that the diagnostic values of miR-1301-3p for benign tumor and PTC were 0.766 and 0.881, respectively. Vitro experiments showed that miR-1301-3p was decreased in TPC-1 cells, then, upregulated miR-1301-3p blocked the TPC-1 cell cycle in G1/S phase, and inhibited the proliferation. PCNA expression was significantly increased in TPC-1 cells and significantly decreased after upregulation of miR-1301-3p.

CONCLUSION

The present study showed that the expression of miR-1301-3p in PTC was significantly decreased, which was related to T and N grade. Upregulation of miR-1301-3p could inhibit cell proliferation and cell migration. miR-1301-3p may serve as a potential biomarker for the early diagnosis and treatment of PTC.

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

Background:

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

Methods:

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

Results:

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

Conclusion:

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

Downregulation of miR‑193a‑3p via targeting cyclin D1 in thyroid cancer

Thyroid cancer (TC) is a frequently occurring malignant tumor with a rising steadily incidence. microRNA (miRNA/miR)‑193a‑3p is an miRNA that is associated with tumors, playing a crucial role in the genesis and progression of various cancers. However, the expression levels of miR‑193a‑3p and its molecular mechanisms in TC remain to be elucidated. The present study aimed to probe the expression of miR‑193a‑3p and its clinical significance in TC, including its underlying molecular mechanisms. Microarray and RNA sequencing data gathered from three major databases, specifically Gene Expression Omnibus (GEO), ArrayExpress and The Cancer Genome Atlas (TCGA) databases, and the relevant data from the literature were used to examine miR‑193a‑3p expression. Meta‑analysis was also conducted to evaluate the association between clinicopathological parameters and miR‑193a‑3p in 510 TC and 59 normal samples from the TCGA database. miRWalk 3.0, and the TCGA and GEO databases were used to predict the candidate target genes of miR‑193a‑3p. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and protein‑protein interaction network enrichment analyses were conducted by using the predicted candidate target genes to investigate the underlying carcinogenic mechanisms. A dual luciferase assay was performed to validate the targeting regulatory association between the most important hub gene cyclin D1 (CCND1) and miR‑193a‑3p. miR‑193a‑3p expression was considerably downregulated in TC compared with in the non‑cancer controls (P<0.001). The area under the curve of the summary receiver operating characteristic was 0.80. Downregulation of miR‑193a‑3p was also significantly associated with age, sex and metastasis (P=0.020, 0.044 and 0.048, respectively). Bioinformatics analysis indicated that a low miR‑193a‑3p expression may augment CCND1 expression to affect the biological processes of TC. In addition, CCND1, as a straightforward target, was validated through a dual luciferase assay. miR‑193a‑3p and CCND1 may serve as prognostic biomarkers of TC. Finally, miR‑193a‑3p may possess a crucial role in the genesis and progression of TC by altering the CCND1 expression.

The role of microRNAs in the pathogenesis of thyroid cancer

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

Differential MicroRNA-Signatures in Thyroid Cancer Subtypes

Thyroid cancer is one of the most common endocrine cancers, with an increasing trend in the last few decades. Although papillary thyroid cancer is the most frequent subtype compared with follicular or anaplastic thyroid cancer, it can dedifferentiate to a more aggressive phenotype, and the recurrence rate is high. The cells of follicular adenomas and follicular carcinomas appear identical in cytology, making the preoperative diagnosis difficult. On the other hand, anaplastic thyroid cancer poses a significant clinical challenge due to its aggressive nature with no effective therapeutic options. In the past several years, the roles of genetic alterations of thyroid tumors have been documented, with a remarkable correlation between genotype and phenotype, indicating that distinct molecular changes are associated with a multistep tumorigenic process. Besides mRNA expression profiles, small noncoding microRNA (miRNA) expression also showed critical functions for cell differentiation, proliferation, angiogenesis, and resistance to apoptosis and finally activating invasion and metastasis in cancer. Several high-throughput sequencing studies demonstrate that miRNA expression signatures contribute clinically relevant information including types of thyroid cancer, tumor grade, and prognosis. This review summarizes recent findings on miRNA signatures in thyroid cancer subtypes.

LINC00311 promotes cancer stem-like properties by targeting miR-330-5p/TLR4 pathway in human papillary thyroid cancer

Growing evidence has suggested that long noncoding RNAs (lncRNAs) play an essential role in the progression of papillary thyroid cancer (PTC). LncRNA LINC00311 was found to be able to regulate many cellular process in several diseases. However, the function and regulatory mechanism of LINC00311 remains unclear in PTC. In the present study, the results showed that the expression of LINC00311 was upregulated in PTC tissues and cells. Furthermore, knockdown of LINC00311 dramatically suppressed spheroid formation, proliferation, migration, and invasion in PTC cells in vitro. Mechanistic investigations revealed that LINC00311 was negatively correlated with the expression of miR‐330‐5p, meanwhile, TLR4 was a direct target of miR‐330‐5p. In addition, rescue assays further determined that LINC00311 contributed to the progression of PTC through regulating TLR4 expression. Taken together, these findings indicated that LINC00311 could promote cancer stem‐like properties by targeting miR‐330‐5p/TLR4 pathway in PTC.