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

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

Introduction

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

Methods

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

Results

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

Conclusion

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

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.

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.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

Emerging roles of the long non-coding RNA 01296/microRNA-143-3p/MSI2 axis in development of thyroid cancer

Thyroid cancer (TC) is an endocrine malignancy with rising incidence. Long non-coding RNAs (lncRNAs) can serve as diagnostic and prognostic biomarkers for TC. Thus, we studied roles of LINC01296 in TC progression. Initially, the Gene Expression Omnibus (GEO) database was used to detect the differentially expressed genes in human TC samples and the potential mechanism. Expression of LINC01296 and miR-143-3p in TC tissues and cells was measured. The transfection of TC cells was conducted with si-LINC01296, si-Musashi 2 (MSI2), mimic or inhibitor of miR-143-3p to determine their effects on TC cell proliferation, migration, invasion, apoptosis and the AKT/STAT3 signaling pathway. Finally, in vivo assay was performed to verify role of miR-143-3p in tumorigenesis of TC cells in nude mice. LINC01296 was predicted to bind to miR-143-3p to modulate MSI2 expression, thus regulating the occurrence and development of TC. LINC01296 was up-regulated, while miR-143-3p was down-regulated in TC cells and tissues. LNC01296 specifically bound to miR-143-3p and MSI2 was a target of miR-143-3p. Besides, LINC01296 silencing or miR-143-3p overexpression inhibited migration, invasion, proliferation and advanced apoptosis of TC cells. Additionally, silenced LINC01296 or overexpressed miR-143-3p reduced phosphorylated STAT3/STAT3, phosphorylated AKT/AKT, B-cell lymphoma-2 (Bcl-2) and CyclinD1 levels but elevated BCL2-associated X (Bax), Cleaved Caspase3 and Caspase3 levels. Also, tumorigenesis of TC cells in nude mice was inhibited with the silencing of LINC01296. In summary, LINC01296/miR-143-3p/MSI2 axis regulated development of TC through the AKT/STAT3 signaling pathway.

Low microRNA-622 expression predicts poor prognosis and is associated with ZEB2 in glioma

Background

MicroRNAs have been recently reported to play an important role in tumorigenesis and progression in several forms of tumors. Previous studies have shown that microRNA-622 (miR-622) was associated with glioma proliferation and invasion. However, the clinical significance of miR-622 in glioma has not been elucidated. The aim of our study was to investigate the clinical values of miR-622, as well as investigate the potential molecular mechanisms in glioma.

Materials and methods

qRT-PCR and Western blot analysis were used to analyze the expression of miR-622 and ZEB2, respectively. Kaplan–Meier analysis and Cox’s proportional hazards model were used in survival analysis. MTT assay, wound healing assay, transwell assay and flow cytometry analysis were carried out to detect the impact of miR-622 on glioma cell proliferation, migration, invasion and apoptosis.

Results

Our result indicated that miR-622 expression was greatly decreased in glioma tissues and cell lines and the downregulation of miR-622 was significantly associated with the advanced pathological grade and low Karnofsky performance score of glioma. In addition, Kaplan–Meier curves with log-rank analysis revealed a close correlation between downregulation of miR-622 expression and low overall survival rate in glioma patients. Furthermore, Cox regression analysis demonstrated that downregulated miR-622 could be considered as an independent poor prognostic indicator in glioma patients. Finally, our findings demonstrated that miR-622 overexpression remarkably suppressed glioma cell proliferation, migration and invasion, while facilitated apoptosis by suppressing ZEB2 in vitro.

Conclusion

Our study suggested that miR-622 may be identified as a valuable prognostic biomarker and a promising therapeutic target for glioma patients.

MicroRNA‑30a regulates cell proliferation, migration, invasion and apoptosis in human nasopharyngeal carcinoma via targeted regulation of ZEB2

MicroRNA-30a (miR-30a) was previously reported to serve as a tumor suppressor able to inhibit the development and progression of certain types of cancer. A number of previous studies demonstrated that zinc finger E-box binding homeobox 2 (ZEB2) may be regulated by miR-30a in clear cell renal cell carcinoma and breast cancer. However, the function of miR-30a in human nasopharyngeal carcinoma (NPC) remains unclear. The present study aimed to investigate the association between miR-30a and ZEB2 in NPC. Therefore, the expression levels of miR-30a and ZEB2 were measured in human NPC cells and tissues from patients with NPC, and the present results suggested that the expression level of miR-30a was significantly decreased in NPC tissues compared with paracancerous tissues. The direct interaction between miR-30a and the untranslated region of ZEB2 was examined using the dual-luciferase reporter assay, and ZEB2 was identified as a direct target of miR-30a. Additionally, the effects of miR-30a and ZEB2 overexpression on cell proliferation, migration, invasion and apoptosis were additionally investigated. Functional experiments identified that overexpression of miR-30a increased apoptosis and suppressed cell proliferation, cell migration and cell invasion by directly targeting ZEB2. Collectively, the present study suggested that miR-30a may serve an important role in the progression of NPC and may represent a novel target for the treatment of patients with NPC.

miR-483-5p Targets MKNK1 to Suppress Wilms' Tumor Cell Proliferation and Apoptosis In Vitro and In Vivo

Background

Wilms’ tumor (WT) is the most common type of renal tumor in children and it has high mortality rates. MicroRNAs (miRNAs) are important regulators of cellular differentiation processes that have been discovered to contribute to the development of various kinds of tumors.

Material/Methods

The Wilms’ tumor tissues and adjacent tissues were obtained from 28 patients to quantity miR-483-5p expression level. The miR-483-5p mimics and scrambles were transfected into the human kidney WT cell line GHINK-1 to evaluate the effect of miR-483-5p on Wilms’ tumor cell proliferation and apoptosis in vitro. A total of 18 female BALB/c nu/nu mice were used to further confirm how miR-483-5p affects Wilms’ tumor in vivo.

Results

In the present study, miR-483-5p was identified to be downregulated in Wilms’ tumor tissues compared with the normal adjacent tissues. Additionally, low expression of mir-483-5p was significantly correlated with unfavorable histology subtypes, lymphatic metastasis, and late clinical stage (stage III and IV). Overexpression of miR-483-5p inhibited the proliferation and colony formation of GHINK-1 (Wilms’ tumor) cells compared with the control group due to enhanced cell apoptosis. Furthermore, miR-483-5p upregulated the protein expression level of caspase-3. Finally, MAP kinase-interacting serine/threonine-protein kinase 1 was identified as a direct target of miR-483-5p, which was confirmed by luciferase reporter assay and Western blotting.

Conclusions

MiR-483-5p suppressed WT cell proliferation via inducing apoptosis through targeting MKNK1. This may provide novel insights into the mechanisms underlying WT and a potential therapeutic candidate for the treatment of WT in the future.

miR‑498 inhibits the growth and metastasis of liver cancer by targeting ZEB2

MicroRNAs (miRNAs) play critical roles in the growth, metastasis and therapeutic resistance of liver cancer. Accumulating evidence suggests that miR-498 is aberrantly expressed in several human malignancies. However, the role and underlying mechanism of miR-498 in liver cancer remain unclear. In the present study, we investigated the potential roles and clinical value of miR-498 in liver cancer. We found that the miR-498 expression level was significantly lower in liver cancer patient tissues than that in healthy control tissues. The expression of miR-498 was also decreased in liver cancer cell lines compared to that noted in a normal human normal liver cell line. miR-498 overexpression markedly inhibited liver cancer cell proliferation, migration and invasion. miR-498 overexpression induced cell cycle arrest and apoptosis while it suppressed epithelial-mesenchymal transition (EMT) in liver cancer cells. Bioinformatic analysis and luciferase reporter assay further identified zinc finger E-box binding homeobox 2 (ZEB2) as a novel target of miR-498. Furthermore, ZEB2 knockdown recapitulated the inhibitory effects of miR-498 overexpression in liver cancer cells. ZEB2 overexpression rescued the inhibition of liver cancer cell proliferation, migration, and invasion by miR-498, indicating that ZEB2 acts as a downstream effector of miR-498 in liver cancer cells. Thus, we demonstrated that miR-498 suppresses the growth and metastasis of liver cancer cells, partly at least, by directly targeting ZEB2, suggesting that miR-498 may serve as a potential biomarker for the diagnosis and therapy of liver cancer.

MicroRNA‑3666 suppresses the growth and migration of glioblastoma cells by targeting KDM2A

MicroRNAs (miRNAs) are acknowledged as essential regulators in human cancer types, including glioblastoma (GBM). However, the functions of microRNA-3666 (miR-3666) in GBM remain unclear. In the present study, it was identified that the expression of miR-3666 was significantly downregulated in GBM tissues compared with adjacent normal tissues by reverse transcription-quantitative polymerase chain reaction. Additionally, miR-3666 was downregulated in GBM cell lines. Furthermore, it was observed that the miR-3666 expression level in patients with GBM was associated with prognosis. With functional experiments, it was identified that overexpression of miR-3666 significantly inhibited the proliferation, migration and invasion of GBM cells in vitro by Cell Counting kit-8 and Transwell assays. Ectopic expression of miR-3666 significantly arrested GBM cells in the G₀ phase by fluorescence activated cell sorting. In terms of the underlying mechanism, it was identified that lysine-specific demethylase 2A (KDM2A) is a direct target of miR-3666 in GBM cells. Overexpression of miR-3666 significantly decreased the expression of KDM2A in GBM cells. Furthermore, it was observed that knockdown of KDM2A significantly suppressed the proliferation, migration and invasion of GBM cells. Collectively, the present results demonstrated that the miR-3666/KDM2A axis serves an important role in the progression of GBM, which provides novel insight into the development of therapeutic strategies for GBM treatment.

PKM2 functions as a potential oncogene and is a crucial target of miR-148a and miR-326 in thyroid tumorigenesis

In this study, we investigated the biological function of pyruvate kinase M2 (PKM2) and its regulation by deregulated microRNAs (miRNAs) in thyroid cancer (TC). The mRNA and protein expression of PKM2 was examined by quantitative reverse transcription PCR and western blot. The biological role of PKM2 was demonstrated through small interfering RNA-mediated knockdown experiments. The regulation of PKM2 by miR-148a and miR-326 was confirmed by western blot, dual luciferase activity assays, and rescue experiments. PKM2 was overexpressed in TC tissues and cell lines. The knockdown of PKM2 in TC cells suppressed cell proliferation, reduced colony formation, and inhibited cell invasion and migration significantly. Luciferase reporter assays revealed that PKM2 is a direct target of two tumor-suppressive miRNAs, miR-148a and miR-326. Re-expressed PKM2 rescued the anticancer effects of miR-148a. Taken together, these data strongly suggest that, apart from gene amplification and mutation, the activation of PKM2 in TC is partly due to the down-regulation of the tumor-suppressive miRNAs miR-148a and miR-326. Thus, PKM2 is overexpressed and plays an oncogenic role in thyroid carcinogenesis.