Hsa-microRNA-101 suppresses migration and invasion by targeting Rac1 in thyroid cancer cells

Profile of MicroRNAs Associated with Death Due to Disease Progression in Metastatic Papillary Thyroid Carcinoma Patients

Papillary thyroid carcinoma (PTC) is the most common neoplasm of the endocrine system and has an excellent long-term prognosis, with low rates of distant metastatic disease. Although infrequent, there are cases of deaths directly related to PTC, especially in patients with metastatic disease, and the factors that could be associated with this unfavorable outcome remain a major challenge in clinical practice. Recently, research into genetic factors associated with PTC has gained ground, especially mutations in the TERT promoter and BRAF gene. However, the role of microRNAs remains poorly studied, especially in those patients who have an unfavorable outcome at follow-up. This paper aims to evaluate molecular markers related to the different pathological processes of PTC, as well as the histological characteristics of the neoplasm, and to compare this profile with prognosis and death from the disease using an analysis of patients treated for metastatic disease in a single tertiary cancer center. Evaluation of microRNA expression in paraffin-embedded tumor specimens was carried out by quantitative PCR using the TaqMan^® Low Density Array (TLDA) system. Metastatic patients who died from progression of PTC had higher expressions of miR-101-3p, miR-17-5p, and miR-191-5p when compared to patients with stable metastatic disease. These findings are of great importance but should be considered as preliminary because of the small sample.

Modulatory role of miRNAs in thyroid and breast cancer progression and insights into their therapeutic manipulation

Over the past few decades, thyroid cancer has become one of the most common types of endocrine cancer, contributing to an increase in prevalence. In the year 2020, there were 586,202 newly diagnosed cases of thyroid cancer around the world. This constituted approximately 3.0% of all patients diagnosed with cancer. The World Health Organization reported that there will be 2.3 million women receiving treatment for breast cancer in 2020, with 685,000. Despite the fact that carcinoma is one of the world's leading causes of death, there is still a paucity of information about its biology. MicroRNAs (miRNAs; miRs) are non-coding RNAs that can reduce gene expression by cleaving the 3' untranslated regions of mRNA. These factors make them a potential protein translation inhibitor. Diverse biological mechanisms implicated in the genesis of cancer are modulated by miRNA. The investigation of global miRNA expression in cancer showed regulatory activity through up regulation and down-regulation in several cancers, including thyroid cancer and breast cancer. In thyroid cancer, miRNA influences several cancers related signaling pathways through modulating MAPK, PI3K, and the RAS pathway. In breast cancer, the regulatory activity of miRNA was played through the cyclin protein family, protein kinases and their inhibitors, and other growth promoters or suppressors, which modulated cell proliferation and cell cycle progression. This article's goal is to discuss key miRNA expressions that are involved in the development of thyroid and breast cancer as well as their therapeutic manipulation for these two specific cancer types.

Induction of RAC1 protein translation and MKK7/JNK-dependent autophagy through dicer/miR-145/SOX2/miR-365a axis contributes to isorhapontigenin (ISO) inhibition of human bladder cancer invasion

Although our previous studies have identified that isorhapontigenin (ISO) is able to initiate autophagy in human bladder cancer (BC) cells by activating JNK/C-Jun/SESN2 axis and possesses an inhibitory effect on BC cell growth, association of autophagy directly with inhibition of BC invasion has never been explored. Also, upstream cascade responsible for ISO activating JNK remains unknown. Thus, we explored both important questions in the current study and discovered that ISO treatment initiated RAC1 protein translation, and its downstream kinase MKK7/JNK phosphorylation/activation, and in turn promoted autophagic responses in human BC cells. Inhibition of autophagy abolished ISO inhibition of BC invasion, revealing that autophagy inhibition was crucial for ISO inhibition of BC invasion. Consistently, knockout of RAC1 also attenuated induction of autophagy and inhibition of BC invasion by ISO treatment. Mechanistic studies showed that upregulation of RAC1 translation was due to ISO inhibition of miR-365a transcription, which reduced miR-365a binding to the 3'-UTR of RAC1 mRNA. Further study indicated that inhibition of miR-365a transcription was caused by downregulation of its transcription factor SOX2, while ISO-promoted Dicer protein translation increased miR-145 maturation, and consequently downregulating SOX2 expression. These findings not only provide a novel insight into the understanding association of autophagy induction with BC invasion inhibition by ISO, but also identify an upstream regulatory cascade, Dicer/miR145/SOX2/miR365a/RAC1, leading to MKK7/JNKs activation and autophagy induction.

MicroRNAs as the critical regulators of cell migration and invasion in thyroid cancer

Thyroid cancer (TC) is one of the most frequent endocrine malignancies that is more common among females. Tumor recurrence is one of the most important clinical manifestations in differentiated TC which is associated with different factors including age, tumor size, and histological features. Various molecular processes such as genetic or epigenetic modifications and non-coding RNAs are also involved in TC progression and metastasis. The epithelial-to-mesenchymal transition (EMT) is an important biological process during tumor invasion and migration that affects the initiation and transformation of early-stage tumors into invasive malignancies. A combination of transcription factors, growth factors, signaling pathways, and epigenetic regulations affect the thyroid cell migration and EMT process. MicroRNAs (miRNAs) are important molecular factors involved in tumor metastasis by regulation of EMT-activating signaling pathways. Various miRNAs are involved in the signaling pathways associated with TC metastasis which can be used as diagnostic and therapeutic biomarkers. Since, the miRNAs are sensitive, specific, and non-invasive, they can be suggested as efficient and optimal biomarkers of tumor invasion and metastasis. In the present review, we have summarized all of the miRNAs which have been significantly involved in thyroid tumor cells migration and invasion. We also categorized all of the reported miRNAs based on their cellular processes to clarify the molecular role of miRNAs during thyroid tumor cell migration and invasion. This review paves the way of introducing a non-invasive diagnostic and prognostic panel of miRNAs in aggressive and metastatic TC patients.

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.

Epigenetic signature associated with thyroid cancer progression and metastasis

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

LncRNA XIST Promotes Migration and Invasion of Papillary Thyroid Cancer Cell by Modulating MiR-101-3p/CLDN1 Axis

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy in the worlds. Long non-coding RNA X-inactive specific transcript (XIST) was found to upregulate in PTC tissues and cell lines. However, the molecular mechanism underlying PTC metastasis and whether XIST plays regulatory role in PTC are still largely unknown. qRT-PCR was performed to detect the expression of lncRNA XIST and mRNAs. Western blotting was carried out to detect CLDN1, MMP2, and MMP9. Transwell assay was used to detect migration and invasion. Starbase bioinformatics prediction and luciferase assay were used to validate the relationship of miR-101-3p and XIST or CLDN1. LncRNA XIST was upregulated in PTC tissues and cells. XIST knockdown suppressed migration and invasion of PTC cells. XIST could directly bind with miR-101-3p. Overexpression of miR-101-3p suppressed migration and invasion of PTC cells. CLDN1 was the target of miR-101-3p, and overexpression of CLDN1 can reverse the inhibition of cell migration and invasion by miR-101-3p, What's more, miR-101-3p inhibition and CLDN1 overexpression can reverse the affection of sh-XIST on migration and invasion of PTC cells inhibition. XIST promotes migration and invasion of papillary thyroid cancer cell via directly regulating miR-101-3p/CLDN1 axis, which is a novel mechanistic of XIST in the regulation of PTC.

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.

miR-224-5p protects dental pulp stem cells from apoptosis by targeting Rac1

Dental pulp stem cells (DPSCs) are reported to be enriched in stem/progenitor cells, however to the best of our knowledge they have yet to be well documented and characterized. In the present study, in order to characterize DPSCs and the effect of microRNAs (miRs/miRNAs) on DPSC properties, a miRNA array was performed between dental periodontal ligament cells (DPLCs) and DPSCs. The results revealed that miR-224-5p (miR-224) was highly expressed in the DPSCs compared with that in the DPLCs. The transfection of DPSCs with an miR-224 inhibitor impaired cell viability. In addition, miR-224 inhibition significantly promoted cell apoptosis in DPSCscompared with the NC group. In silico analysis and a dual-luciferase reporter assay demonstrated that miR-224 targets the 3′-untranslated region of the Rac family small GTPase 1 (Rac1) gene. miR-224 downregulation resulted in the increased expression of Rac1 in DPSCs compared with DPLCs. Furthermore, miR-224 inhibition caused augmented mitogen-activated protein kinase 8, caspase-3, caspase-9 and Fas ligand expression in DPSC, which may be recovered by Rac1 silencing with transfection with short hairpin RNA-Rac1. Furthermore, Annexin V-fluorescein isothiocyanate/propidium iodide flow cytometry indicated that the silencing of Rac1 restored the pro-apoptotic DPSC cell number with miR-224 transfection. Therefore, the results of the present study suggested miR-224 in DPSC serves an important function in protecting cells against apoptosis by downregulating Rac1 expression, and also identified miR-224 as a novel miRNA in regulating the features of DPSC.

MicroRNA signature predicts survival in papillary thyroid carcinoma

Papillary thyroid cancer (PTC) accounts for the majority of malignant thyroid tumors. Recently, several microRNA (miRNA) expression profiling studies have used bioinformatics to suggest miRNA signatures as potential prognostic biomarkers in various malignancies. However, a prognostic miRNA biomarker has not yet been established for PTC. The aim of the present study was to identify miRNAs with prognostic value for the overall survival (OS) of patients with PTC by analyzing high-throughput miRNA data and their associated clinical characteristics downloaded from The Cancer Genome Atlas database. From our dataset, 150 differentially expressed miRNAs were identified between tumor and nontumor samples; of these miRNAs, 118 were upregulated and 32 were downregulated. Among the 150 differentially expressed miRNAs, a four miRNA signature was identified that reliably predicts OS in patients with PTC. This miRNA signature was able to classify patients into a high-risk group and a low-risk group with a significant difference in OS (P < .01). The prognostic value of the signature was validated in a testing set ( P < .01). The four miRNA signature was an independent prognostic predictor according to the multivariate analysis and demonstrated good performance in predicting 5-year disease survival with an area under the receiver operating characteristic curve area under the curve (AUC) score of 0.886. Thus, this signature may serve as a novel biomarker for predicting the survival of patients with PTC.

Overexpression of miR-101-2 in donor cells improves the early development of Holstein cow somatic cell nuclear transfer embryos

Accumulating studies have suggested that microRNA play a part in regulating multiple cellular processes, such as cell proliferation, apoptosis, the cell cycle, and embryo development. This study explored the effects of miR-101-2 on donor cell physiological status and the development of Holstein cow somatic cell nuclear transfer (SCNT) embryos in vitro. Holstein cow bovine fetal fibroblasts (BFF) overexpressing miR-101-2 were used as donor cells to perform SCNT; then, cleavage rate, blastocyst rate, inner cell mass-to-trophectoderm ratio, and the expression of some development- and apoptosis-related genes in different groups were analyzed. The miR-101-2 suppressed the expression of inhibitor of growth protein 3 (ING3) at mRNA and protein levels, expedited cell proliferation, and decreased apoptosis in BFF, suggesting that ING3, a target gene of miR-101-2, is a potential player in this process. Moreover, by utilizing donor cells overexpressing miR-101-2, the development of bovine SCNT embryos in vitro was significantly enhanced; the apoptotic rate in SCNT blastocysts was reduced, and the inner cell mass-to-trophectoderm ratio and SOX2, POU5F1, and BCL2L1 expression significantly increased, whereas BAX and ING3 expression decreased. Collectively, these findings suggest that miR-101-2 promotes BFF proliferation and vitality, reduces their apoptosis, and improves the early development of SCNT embryos.

MicroRNA-101 Targets CXCL12-Mediated Akt and Snail Signaling Pathways to Inhibit Cellular Proliferation and Invasion in Papillary Thyroid Carcinoma

Escalating evidence suggests that microRNA-101 (miR-101) is implicated in the development and progression of various cancers, including papillary thyroid carcinoma (PTC). However, the biological function and molecular mechanisms of miR-101 in PTC are still unclear. In this study, we demonstrated that miR-101 expression was significantly decreased in PTC tissues and cell lines. Clinically, a low level of miR-101 was positively associated with advanced histological stages and lymph node and distant metastases. The expression of CXCL12 was negatively correlated with miR-101 level in PTC. CXCL12 was validated as a direct target of miR-101 in PTC cells. Functional experiments proved that miR-101 markedly reduced the proliferation, apoptosis escape, migration, and invasion of PTC cells. Moreover, CXCL12 restoration rescued the suppressive effects of miR-101 on PTC cells by activating Akt- and EMT-associated signaling pathways. Overall, miR-101 exerts oncostatic effects on PTC by downregulating CXCL12 and repressing its downstream Akt and Snail signaling pathways, suggesting that miR-101/CXCL12/Akt or Snail axis may serve as a potential therapeutic target for PTC.

MicroRNA-224 enhances the osteoblastic differentiation of hMSCs via Rac1

Osteogenesis is the differentiation of mesenchymal stem cells (MSCs) into osteoblasts. MicroRNAs (miRNAs) are short noncoding RNAs that target specific genes to mediate translational activities. In this study, we investigated how miR-224 regulates the osteoblastic differentiation of human MSCs (hMSCs) as well as the underlying mechanism. The results revealed the upregulation of miR-224 during hMSC differentiation. In vitro experiments showed that the downregulation of miR-224 suppressed the differentiation of hMSCs into osteoblasts. However, upregulation of miR-224 was concomitant with increased expression of relevant genes and augmented activity of alkaline phosphatase. Furthermore, the results indicated that Rac1 acted as the bona fide target of miR-224 and that Rac1 depletion promoted osteogenic differentiation in miR-224-silenced hMSCs. In addition, we found that both JAK/STAT3 and Wnt/β-catenin pathways were repressed by Rac1 depletion using quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and immunofluorescence. Our data indicate a novel molecular mechanism in relation to hMSCs differentiation into osteoblasts, which may facilitate bone anabolism via miR-224. SIGNIFICANCE OF THE STUDY: In this study, we mainly explored the effects of miR-224 on hMSCs differentiation into osteoblasts. We find that induced miR-224 expression in hMSCs is considered closely associated with specific osteogenesis-related genes, alkaline phosphatase activity, and matrix mineralization, indicating that miR-224 may serve as a promising biomarker for osteogenic differentiation. Our data indicate a novel molecular mechanism in relation to hMSCs differentiation into osteoblasts, which may facilitate bone anabolism via miR-224.

MiR-101: a potential therapeutic target of cancers

MicroRNAs (miRNAs) are small noncoding RNAs that could regulate gene expressions transcriptionally or post-transcriptionally through binding to 3' untranslated region (3'UTR) of target messenger RNAs (mRNAs), which were identified to be associated with tumorigenesis in various neoplasms. Among them, miR-101, encoded by two precursor transcripts (miR-101-1 and miR-101-2), was recognized to serve as a tumor suppressor via targeting critical oncogenes or anti-oncogenes. Additionally, studies have shown that miR-101 was participated in multiple cancer-related biological processes, including proliferation, apoptosis, angiogenesis, drug resistance, invasion and metastasis. In this review, we aim to summarize the function of miR-101 in different biological processes by figuring out the underlying target gene networks and explore its potential role as a biomarker in diverse neoplasms, which will provide a brand-new insight in molecular targeting cancer treatment.

Prognostic implications of decreased microRNA-101-3p expression in patients with non-small cell lung cancer

To investigate the expression level of microRNA-101-3p (miR-101-3p) and its possible association with progression, prognosis and chemotherapy in patients with non-small cell lung cancer (NSCLC), the Gene Expression Omnibus (GEO) database was used. Quantitative polymerase chain reaction was used to verify the expression in 327 NSCLC and 42 adjacent normal lung tissues, of which 42 viable tissues were paired with nearby normal lung tissues. Based on the Cox regression model, univariate and multivariate analyses were used to address the factors that had effects on overall survival (OS) and disease-free survival (DFS) rate. Data from the GEO database demonstrated that the miR-101-3p expression in NSCLC was downregulated, compared with normal lung cancer. Survival analysis through univariate and multivariate models indicated that the miR-101-3p expression level was a crucial risk factor for OS and DFS in patients with NSCLC. A number of clinical parameters were determined to be associated with miR-101-3p expression, including tumor diameter, lymph node metastasis and tumor-node-metastasis stage. Adjuvant chemotherapy with high expression of miR-101-3p was determined to increase OS and DFS in patients with NSCLC, compared with patients with de novo or low expression of miR-101-3p. The present results demonstrated that miR-101-3p expression levels were associated with NSCLC progression and prognosis, which indicated that miR-101-3p may serve as a biomarker for patients with NSCLC who have received adjuvant chemotherapy.

TWIST1/miR-584/TUSC2 pathway induces resistance to apoptosis in thyroid cancer cells

TWIST1, a transcription factor, plays a pivotal role in cancer initiation and progression. Anaplastic thyroid carcinoma (ATC) is one of the deadliest human malignancies; TWIST1 is overexpressed in ATC and increases thyroid cancer cell survival, migration and invasion. The molecular mechanisms underlying the effects of TWIST1 are partially known. Here, using miRNome profiling of papillary thyroid cancer cells (TPC-1) ectopically expressing TWIST1, we identified miR-584. We showed that TWIST1 directly binds miR-584 using chromatin immunoprecipitation. Importantly, miR-584 was up-regulated in human ATC compared to papillary thyroid carcinoma (PTC) and normal thyroid samples. Overexpression of miR-584 in TPC cells induced resistance to apoptosis, whereas stable transfection of anti-miR-584 in TPC-TWIST1 and 8505C cells increased the sensitivity to apoptosis. Using bioinformatics programs, we identified TUSC2 (tumor suppressor candidate 2) as a novel target of miR-584. TUSC2 mRNA and protein levels were decreased in TPC miR-584 and increased in TPC-TWIST1 anti-miR-584 cells. Luciferase assays demonstrated direct targeting. Restored expression of TUSC2 rescued the inhibition of apoptosis induced by miR-584. Finally, qRT-PCR and immunohistochemical analysis showed that TUSC2 was down-regulated in ATC and PTC samples compared to normal thyroids. In conclusion, our study identified a novel TWIST1/miR-584/TUSC2 pathway that plays a role in resistance to apoptosis of thyroid cancer cells.

Role of microRNAs in endocrine cancer metastasis

The deregulation of transcription and processing of microRNAs (miRNAs), as well as their function, has been involved in the pathogenesis of several human diseases, including cancer. Despite advances in therapeutic approaches, cancer still represents one of the major health problems worldwide. Cancer metastasis is an aggravating factor in tumor progression, related to increased treatment complexity and a worse prognosis. After more than one decade of extensive studies of miRNAs, the fundamental role of these molecules in cancer progression and metastasis is beginning to be elucidated. Recent evidences have demonstrated a significant role of miRNAs on the metastatic cascade, acting either as pro-metastatic or anti-metastatic. They are involved in distinct steps of metastasis including epithelial-to-mesenchymal transition, migration/invasion, anoikis survival, and distant organ colonization. Studies on the roles of miRNAs in cancer have focused mainly on two fronts: the establishment of a miRNA signature for different tumors, which may aid in early diagnosis using these miRNAs as markers, and functional studies of specific miRNAs, determining their targets, function and regulation. Functional miRNA studies on endocrine cancers are still scarce and represent an important area of research, since some tumors, although not frequent, present a high mortality rate. Among the endocrine tumors, thyroid cancer is the most common and best studied. Several miRNAs show lowered expression in endocrine cancers (i.e. miR-200s, miR-126, miR-7, miR-29a, miR-30a, miR-137, miR-206, miR-101, miR-613, miR-539, miR-205, miR-9, miR-195), while others are commonly overexpressed (i.e. miR-21, miR-183, miR-31, miR-let7b, miR-584, miR-146b, miR-221, miR-222, miR-25, miR-595). Additionally, some miRNAs were found in serum exosomes (miR-151, miR-145, miR-31), potentially serving as diagnostic tools. In this review, we summarize studies concerning the discovery and functions of miRNAs and their regulatory roles in endocrine cancer metastasis, which may contribute for the finding of novel therapeutic targets. The review focus on miRNAs with at least some identified targets, with established functions and, if possible, upstream regulation.

Therapeutic effects of adenovirus-mediated CD and NIS expression combined with Na131I/5-FC on human thyroid cancer

Thyroid cancer is the most common type of malignant endocrine tumor diagnosed. Previous studies have indicated that gene therapy is the most promising and effective therapeutic method for thyroid cancer. Therefore, in the present study, Na¹³¹I/5-fluorocytosine (5-FC) treatment was combined with cytosine deaminase (CD, encoded by the CDA gene) and sodium iodide symporter (NIS, encoded by the SLC5A5 gene) to act together as a therapeutic tool for thyroid cancer. The present study explored the combined cytotoxic effects of adenovirus-mediated CD and NIS under the control of the progression elevated gene-3 (PEG-3) promoter (Ad-PEG-3-CD-NIS) with Na¹³¹I/5-FC against the human thyroid cancer TT cell line in vitro. The PEG-3 fragment was obtained by polymerase chain reaction (PCR) using rat genomic DNA as the template, and then Ad-PEG-3-CDA-SLC5A5 was constructed using XbaI. TT cells were transfected by recombinant adenovirus. The method of reverse transcription-quantitative PCR was performed to test the expression of CD and NIS at the level of transcription. The morphological change was assessed by fluorescence microscopy and investigated by western blot analysis. An MTT assay was used to determine the number of living cells inhibited by single or combination therapies on TT cells. The results indicated that the PEG-3 was successfully cloned, and was also positively regulated in 293 cells. CDA and SLC5A5 genes were highly expressed in TT cells. Na¹³¹I combined with 5-FC significantly decreased the human thyroid cancer cells. In conclusion, combination therapy of Ad-PEG3-CDA-SLC5A5 and Na¹³¹I/5-FC induces significantly more apoptotic characteristics than either single treatment with Ad-PEG-3-CDA-SLC5A5 or Na¹³¹I/5-FC, and low doses of Ad-PEG-3-CDA-SLC5A5 enhanced the cytotoxic effects.

Let-7a inhibits migration, invasion and tumor growth by targeting AKT2 in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy. Increasing evidence showed that microRNAs (miRNAs) play an important role in the PTC progression. In our study, the result showed that let-7a is significantly downregulated in PTC tissues and thyroid cancer cell lines. Overexpression of let-7a suppressed PTC cell proliferation, migration and invasion. Interestingly, we found that AKT2 was a direct target of let-7a and the expression levels of AKT2 were also observed to inversely correlate with let-7a expression in PTC tissues. Furthermore, enhancing AKT2 expression partially reversed the inhibitory effects of let-7a in PTC. Taken together, these findings suggest that let-7a acts as a novel suppressor by targeting the AKT2 gene and might be a candidate target for the development of novel therapeutic strategies to treat papillary thyroid carcinoma.

A comprehensive study of smoking-specific microRNA alterations in head and neck squamous cell carcinoma

OBJECTIVE

While tobacco smoking is a well-known risk factor for head and neck squamous cell carcinoma (HNSCC), the molecular mechanisms underlying tobacco-induced HNSCC remain unclear. This study sought to comprehensively identify microRNA (miRNA) alterations and evaluate their clinical relevance in smoking-induced HNSCC pathogenesis and progression.

MATERIALS AND METHODS

Using small RNA-sequencing data and clinical data from 145 HNSCC patients, we performed a series of differential expression and correlation analyses to identify a panel of tobacco-dysregulated miRNAs associated with key clinical characteristics in HNSCC. We then examined the expression patterns of these miRNAs in normal epithelial cell lines following exposure to cigarette smoke extract.

RESULTS

Our analyses revealed distinct panels of miRNAs to be dysregulated with smoking status and associated with additional clinical features, including tumor stage, metastasis, anatomic site, and patient survival. The differential expression of key miRNAs, including miR-101, miR-181b, miR-486, and miR-1301, was verified in cigarette-treated epithelial cell lines, suggesting their potential roles in the early development of smoking-related HNSCCs.

CONCLUSION

Specific alterations in miRNA expression may be traced to tobacco use and are associated with important HNSCC clinical characteristics. Future studies of these miRNAs may be valuable for furthering the understanding and targeted treatment of smoking-associated HNSCC.

miR-200b inhibits CD133+ glioma cells by targeting the AKT pathway

MicroRNA-200b (miR-200b) is a tumor suppressor in multiple tumor types, including gastric cancer, breast cancer, ovarian cancer and glioma. The biological significance of a known normal and cancer stem cell marker, CD133, remains elusive. The aim of the present study was to identify the function and mechinism of miR-200b in suppressing CD133⁺ glioma cells. CD133⁺ glioma cells were sorted by flow cytometry. The expression of miR-200b, Ki67, GAP43, GFAP and CD133 were tested by reverse transcription-quantitative polymerase chain reaction. The binding of miR-200b to prominin 1 (PROM1) was certificated by luciferase reporter assay. Cell proliferation was analyzed by bromodeoxyuridine staining. The protein level of CD133, p-AKT, AKT and Notch1 was detected by western blot analysis. Analysis of glioma samples revealed that CD133 expression is negatively associated with miR-200b. PROM1, which is the gene that codes CD133, was certified to be a target of miR-200b. miR-200b expression inhibited the stemness properties and division of the CD133⁺ glioma cells. Our results identified a miR-200b/CD133/PI3K/Akt signaling axis, exploring the fundamental role of miR-200b and CD133 in glioma stem cell behavior.

Dynamic monitoring of circulating microRNAs as a predictive biomarker for the diagnosis and recurrence of papillary thyroid carcinoma

Circulating microRNAs (miRNAs/miRs) are considered to be potential biomarkers for numerous types of cancer. However, previous investigations into the expression of miRNAs in the serum of patients with papillary thyroid carcinoma (PTC) to predict diagnosis, prognosis and recurrence have reported conflicting results, and the role of miRNAs remains unclear. The present study dynamically assessed the circulating miRNA profile in patients with PTC and determined whether miRNAs in the serum could be used as biomarkers for the diagnosis, prognosis and recurrence of PTC. The expression levels of 3 reportedly upregulated miRNAs (miR-222, miR-221 and miR-146b) were analyzed using reverse transcription-quantitative polymerase chain reaction in 106 patients with PTC, 35 patients with benign thyroid nodules (BTN) and 40 paired controls. Patients with either newly diagnosed PTC or BTN who were undergoing thyroidectomies were recruited for a dynamic analysis of preoperative and postoperative serum miRNA levels. The results indicated that the expression levels of serum miR-222, miR-221 and miR-146b were significantly increased in patients with newly diagnosed PTC compared with controls and patients with BTN. Receiver operating characteristic curve analysis indicated that these miRNAs had a high diagnostic sensitivity and specificity for PTC prior to surgery. The expression of these three miRNAs in serum was significantly associated with poorer prognostic variables, including extrathyroidal invasion, metastatic lymph nodes and high-risk or advanced tumor node metastasis stage. More notably, the present study identified 2.36-, 2.69- and 5.39-fold reductions in the serum levels of miR-222, miR-221 and miR-146b, respectively, subsequent to patients undergoing a thyroidectomy. In addition, miR-222, miR-221 and miR-146b were overexpressed in the PTC with recurrence group compared with the PTC without recurrence group. Collectively, dynamic monitoring of circulating miRNAs may serve as a non-invasive biomarker for the diagnosis of PTC and the postoperative monitoring of its progression and recurrence.

miRNA dysregulation and the risk of metastasis and invasion in papillary thyroid cancer: a systematic review and meta-analysis

Thyroid cancer (TC) is the most common endocrine malignancy, with an incidence continuing to grow every year. Although thyroid cancer as a whole is generally indolent and relatively easy to treat, some subtypes carry a higher rate of metastasis and cancer-related mortality. A growing number of studies have focused on the dysregulation of miRNAs in TC. However, differences in methods make comparison of gene profiling data difficult. A meta-analysis of published studies comparing miRNA expression data of invasive thyroid carcinoma with paired non-invasive tumors or normal tissues was performed by searching the literature for “invasion”, “thyroid cancer”, and “miRNA”. This revealed 29 dysregulated miRNAs associated with TC in 16 articles; the presence of invasion was confirmed in each respective article by laboratory research or patient follow-up. Among these miRNAs, miRNA-146b, miRNA-221, and miRNA-222 were analyzed further due to their higher frequencies across multiple studies. Of these studies, 6 were included in the meta-analysis, as they compared invasive PTC with paired normal tissues or non-invasive PTC.

Expression of MicroRNAs in Thyroid Carcinoma

MicroRNA (miRNA) are negative regulators of gene expression and subsequent protein production. This method of action translates into regulatory control over cellular processes, including development, signaling, metabolism, and apoptosis. A broad range of miRNA are shown to have abnormal expressions in thyroid cancers which could explain the pathology of tumor oncogenesis and disease progression. A review is conducted of the current research on miRNA dysregulation in thyroid cancers, including papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), anaplastic thyroid cancer (ATC), and medullary thyroid carcinoma (MTC). Dysregulated miRNA and their associated regulatory pathways are identified and their oncogenic and pathological significance are discussed.

MiR-101 Targets the EZH2/Wnt/β-Catenin the Pathway to Promote the Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells

Mounting evidence indicates that microRNAs (miRNAs) are involved in multiple processes of osteogenic differentiation. MicroRNA-101 (miR-101), identified as a tumor suppressor, has been implicated in the pathogenesis of several types of cancer. However, the expression of miR-101 and its roles in the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) remain unclear. We found that the miR-101 expression level was significantly increased during the osteogenic differentiation of hBMSCs. MiR-101 depletion suppressed osteogenic differentiation, whereas the overexpression of miR-101 was sufficient to promote this process. We further demonstrated that enhancer of zeste homolog 2 (EZH2) was a target gene of miR-101. EZH2 overexpression and depletion reversed the promoting or suppressing effect of osteogenic differentiation of hBMSCs, respectively, caused by miR-101. In addition, we showed that miR-101 overexpression promoted the expression of Wnt genes, resulting in the activation of the Wnt/β-catenin signaling pathway by targeting EZH2, while the activity of β-catenin and the Wnt/β-catenin signaling pathway was inhibited by ICG-001, a β-Catenin inhibitor, which reversed the promoting effect of miR-101. Finally, miR-101 also promotes in vivo bone formation by hBMSCs. Collectively, these data suggest that miR-101 is induced by osteogenic stimuli and promotes osteogenic differentiation at least partly by targeting the EZH2/Wnt/β-Catenin signaling pathway.

MiR-101 targets USP22 to inhibit the tumorigenesis of papillary thyroid carcinoma

Increasing evidence suggests that microRNA-101 (miR-101) is involved in the progression of various human cancers, including papillary thyroid carcinoma (PTC). However, the biological functions of miR-101 and underlying molecular mechanisms in PTC remain largely unknown. In this study, we demonstrated that miR-101 underexpression in PTC tissue was associated with lymph node metastasis and poor prognosis of PTC patients. MiR-101 reduced PTC cell proliferation, apoptosis resistance, and invasion. Ubiquitin-specific protease 22 (USP22) was confirmed as a direct target of miR-101. USP22 restoration attenuated the inhibitory effects of miR-101 on PTC malignant traits in vitro. In vivo, miR-101 overexpression or USP22 depletion reduced the tumorigenesis of PTC. Overall, our findings provide new insight into the mechanism of PTC inhibition by miR-101, suggesting the potential of miR-101 as a therapeutic target in PTC patients.

Inhibition of the Rac1-WAVE2-Arp2/3 signaling pathway promotes radiosensitivity via downregulation of cofilin-1 in U251 human glioma cells

The Ras-related C3 botulinum toxin substrate 1 (Rac1)-WASP-family verprolin-homologous protein-2 (WAVE2)-actin-related protein 2/3 (Arp2/3) signaling pathway has been identified to be involved in cell migration and invasion in various types of cancer cell. Cofilin‑1 (CFL‑1), which is regulated by the Rac1‑WAVE2‑Arp2/3 signaling pathway, may promote radioresistance in glioma. Therefore, the present study aimed to investigate the potential role of the Rac1‑WAVE2‑Arp2/3 signaling pathway in radioresistance in U251 human glioma cells and elucidate its affect on CFL‑1 expression. Western blot analysis was performed to evaluate the protein expression of CFL‑1. In the present study, Rac1 was inhibited by NSC 23766, WAVE2 was inhibited by transfection with short hairpin (sh)RNA‑WAVE2 using Lipofectamine™ 2000 and Arp2/3 was inhibited by CK‑666. Cell viability was measured using the 3‑(4,5‑dimethylthiazol‑2‑yl)-2,5‑diphenyltetrazolium bromide assay, the cell migration ability was examined by a wound‑healing assay, and the cell invasion ability was assessed using a Transwell culture chamber system. The results showed that inhibition of the Rac1‑WAVE2‑Arp2/3 signaling pathway using NSC 23766, shRNA‑WAVE2 or CK‑666 reduced the cell viability, migration and invasion abilities in U251 human glioma cells, concordant with a reduced expression of CFL‑1. Furthermore, the expression of CFL‑1 was significantly increased in radioresistant U251 glioma cells when compared with normal U251 human glioma cells. These findings indicate that inhibition of the Rac1‑WAVE2‑Arp2/3 signaling pathway may promote radiosensitivity, which may partially result from the downregulation of CFL‑1 in U251 human glioma cells.

MECHANISMS IN ENDOCRINOLOGY: MicroRNA in diagnostics and therapy of thyroid cancer

MicroRNAs, short non-coding regulators of the gene expression, are subjects of numerous investigations assessing their potential use in the diagnostics and management of human diseases. In this review, we focus on studies that analyze the utility of microRNAs as novel diagnostic and therapeutic tools in follicular cell-derived thyroid carcinomas. This very interesting and promising field brings new insight into future strategies for personalized medicine.

miR-4299 mediates the invasive properties and tumorigenicity of human follicular thyroid carcinoma by targeting ST6GALNAC4

Altered sialylation is closely associated with tumor progression and invasiveness. Micro-RNAs endogenous regulators of gene expression have been implicated in human thyroid carcinoma invasiveness. The objective of this study is to examine the alterations of miR-4299 and ST6GALNAC family in human follicular thyroid carcinoma during metastatic process. qRT-PCR showed the differential expressional profiles of miR-4299 and ST6GALNAC family in three kinds of thyroid cell lines (FTC-133,FTC-238, Nthy-ori 3-1) and clinical tissue specimens(malignant and borderline). The altered expression levels of ST6GALNAC4 were corresponding to invasive phenotypes of FTC-133 and FTC-238 cells both in vitro and in vivo. Further date indicated that miR-4299 regulated tumor progression and invasiveness by directly targeting ST6GALNAC4. This study implies the potential therapeutic application of miR-4299 and ST6GALNAC4 in modulating the invasion and tumorigenicity of follicular thyroid carcinoma cell.

Cyclooxygenase-2, a Potential Therapeutic Target, Is Regulated by miR-101 in Esophageal Squamous Cell Carcinoma

BACKGROUND & AIMS

Cyclooxygenase-2 (COX-2) is known to promote the carcinogenesis of esophageal squamous cell carcinoma (ESCC). There are no reports on whether microRNAs (miRNAs) regulate COX-2 expression in ESCC. This study investigated the effect of miR-101 on ESCC through modulating COX-2 expression in ESCC.

METHODS

Real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify miR-101 expression in ESCC clinical tissues and cell lines. The effects of miR-101 on ESCC progression were evaluated by cell counting kit-8 (CCK8), transwell migration and invasion assays, as well as by flow cytometry. The COX-2 and PEG2 levels were determined by western blot and enzyme-linked immunosorbent assays (ELISA). The luciferase reporter assay was used to verify COX-2 as a direct target of miR-101. The anti-tumor activity of miR-101 in vivo was investigated in a xenograft nude mouse model of ESCC.

RESULTS

Downregulation of miR-101 was confirmed through comparison of 30 pairs of ESCC tumor and adjacent normal tissues (P < 0.001), as well as in 11 ESCC cell lines and a human immortalized esophageal cell line (P < 0.001). Transfection of miR-101 in ESCC cell lines significantly suppressed cell proliferation, migration, and invasion (all P < 0.001). The antitumor effect of miR-101 was verified in a xenograft model. Furthermore, COX-2 was shown to be a target of miR-101.

CONCLUSIONS

Overexpression of miR-101 in ESCC inhibits proliferation and metastasis. Therefore, the miR-101/COX-2 pathway might be a therapeutic target in ESCC.

Association between microRNA polymorphisms and papillary thyroid cancer susceptibility

OBJECTIVES

Papillary thyroid cancer (PTC) is the most common subtype of thyroid cancer, which accounts for 80-90% of all thyroid cancer cases. Though the pathological mechanism hasn't been fully understood, it is reported that both environmental and genetic factor may contribute to the PTC susceptibility. MicroRNAs (miRNAs) are small non-coding RNA molecules which function as the suppressors to participate in a variety of biological processes. Accumulating evidence suggests that polymorphisms of miRNAs were associated with the tumorigenesis of various cancers, including PTC. In this article, we focus on the association between four common microRNA polymorphisms (miR-146a, miR-608, miR-933, and miR-149) and PTC risk in a Han Chinese population.

METHODS

In this case-control study, we recruited 1,398 participants in total, including 369 PTC patients, 278 patients with thyroid benign nodules (BN) and 751 normal controls. The miRNAs polymorphisms were genotyped and analyzed by using MALDI-TOF mass spectrometry. The odd ratios and their 95% confidence interval (95% CI) were calculated to evaluate the association between miRNAs polymorphisms and PTC risk. Furthermore, a meta-analysis based on previous studies was conducted to comprehensively assess the diagnostic performance of miR-146a in the PTC diagnosis.

RESULTS

The miR-146a polymorphisms were shown to be significantly correlated with elevated risk of PTC under the heterozygous, homozygous, dominant and allelic models by comparing the genotype distribution between PTC cases and healthy controls, as well as between PTC cases and BN cases. However, the result of meta-analysis showed no significant association between miR-146a polymorphisms and PTC risk.

CONCLUSIONS

Our study indicated that the miR-146a polymorphism was significantly associated with PTC risk. In contrast, meta-analysis revealed no evidence of association between miR-146a variants and PTC risk. Further studies are required to elucidate the role of miR-146a in the etiology of PTC.

MicroRNA-101 inhibits the migration and invasion of intrahepatic cholangiocarcinoma cells via direct suppression of vascular endothelial growth factor-C

MicroRNAs (miRs) have important roles in the pathogenesis of human malignancy. It has previously been suggested that deregulation of miR‑101 is associated with the progression of intrahepatic cholangiocarcinoma (ICC); however, the exact role of miR‑101 in the regulation of ICC metastasis remains largely unknown. The present study demonstrated that the expression levels of miR‑101 were significantly decreased in ICC tissue, as compared with matched adjacent normal tissue. Furthermore, miR‑101 was downregulated in the ICC‑9810 human ICC cell line, as compared with in the normal human intrahepatic biliary epithelial cell (HIBEC) line. Vascular endothelial growth factor (VEGF)‑C was identified as a target gene of miR‑101 in ICC‑9810 cells. The expression of VEGF‑C was negatively regulated by miR‑101 at the post‑transcriptional level in ICC‑9810 cells. Further investigation demonstrated that overexpression of miR‑101 markedly suppressed the migration and invasion of ICC‑9810 cells, and these effects were similar to those observed following VEGF‑C knockdown. Conversely, restoration of VEGF‑C reversed the inhibitory effects of miR‑101 overexpression on ICC‑9810 cell migration and invasion, thus suggesting that miR‑101 may suppress ICC‑9810 cell migration and invasion, at least partly via inhibition of VEGF‑C. It was also demonstrated that the mRNA and protein expression levels of VEGF‑C were frequently upregulated in ICC tissue and cells, and its expression level was inversely correlated with that of miR‑101 in ICC tissue. In conclusion, the present study identified important roles for miR‑101 and VEGF‑C in ICC, suggesting that miR‑101/VEGF‑C signaling may be a promising diagnostic and/or therapeutic target for ICC.

Shlnc-EC6 regulates murine erythroid enucleation by Rac1-PIP5K pathway

Long noncoding RNAs (LncRNAs) are longer than 200 nucleotide noncoding RNAs without apparent functional coding capacity that function as regulators of cell growth and development. In recent years, increasing evidence implicates the involvement of LncRNAs in erythropoiesis. shlnc-EC6 is a LncRNA associated with erythroid differentiation but the mechanism remains undefined. In this study, we found that knockdown of shlnc-EC6 in purified mouse fetal liver erythroid progenitor and hematopoietic stem cells (FLEPHSCs) significantly blocked erythroid enucleation. We also showed that Rac1 was negatively regulated by shlnc-EC6 at the posttranscriptional level via specific binding to sites within the 3'UTR of Rac1 mRNA. Moreover, we found that knockdown of shlnc-EC6 led to upregulation of Rac1, followed by the activation of the downstream protein PIP5K, and subsequently resulted in the inhibition of enucleation in cultured mouse fetal erythroblasts. Thus, our findings suggest that shlnc-EC6 acts as a novel modulator to regulate mouse erythropoiesis via Rac1/PIP5K signaling pathway.

MicroRNA-145 inhibits human papillary cancer TPC1 cell proliferation by targeting DUSP6

MicroRNAs (miRNAs) are small, non-coding RNAs that modulate gene expression by negatively regulating the stability or translational efficiency of their target mRNAs. The aim of this study was to investigate the expression of microRNA-145 (miR-145) in human papillary thyroid cancer and its potential function. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to determine the expression level of miR-145 in ten papillary thyroid cancer and adjacent normal specimens. The function of miR-145 overexpression on the proliferation of human TPC1 thyroid cancer cells was conducted by MTT assays and by colony-formation assays. Western blot was used to validate the impact of miR-145 on the protein expression of the target gene. Luciferase reporter assays were employed to validate a putative target of miR-145. MiR-145 expression was relatively decreased in papillary thyroid cancer specimens compared with adjacent normal tissues (P<0.05). MTT assays and colony-formation assays showed that overexpression of miR-145 suppressed TPC1 cell growth. Luciferase assays using a reporter carrying a putative miR-145 target site in the 3' untranslated region of DUSP6 revealed that miR-145 directly targets DUSP6. Overexpression of miR-145 led to downregulation of DUSP6 at protein level as assessed by Western blot. Targeted knockdown of DUSP6 by siRNA significantly inhibited the proliferation of TPC1 cells. The overexpression of miR-145 inhibited TPC1 cellular growth by targeting DUSP6; this finding implies a better understanding of initiation and progression of papillary thyroid cancer.

Upregulation of miR-494 Inhibits Cell Growth and Invasion and Induces Cell Apoptosis by Targeting Cleft Lip and Palate Transmembrane 1-Like in Esophageal Squamous Cell Carcinoma

BACKGROUND

Potential target genes of microRNA (miR)-494 have been reported in many types of cancers. However, the role of miR-494 in esophageal squamous cell carcinoma (ESCC) remains unknown.

AIM

This study focused on the expression and biological function of miR-494 in ESCC.

METHODS

Using bioinformatics analyses, we found that cleft lip and palate transmembrane 1-like (CLPTM1L) was a potential target of miR-494. We performed quantitative real-time (qRT) PCR assays in 37 ESCC tumor tissues to determine the expression of miR-494 and CLPTM1L mRNA, and we analyzed the correlation between both of these factors and clinical characteristics. The cell counting kit-8 and colony formation assays were used to evaluate the effects of miR-494 expression on the proliferation of ESCC cells. The transwell migration assay and flow cytometric apoptosis assay were performed to study the influence of miR-494 on the invasion and apoptosis of ESCC cells. Western blotting, luciferase assays, and CLPTM1L knockdown experiments were used to determine whether CLPTM1L was a target of miR-494.

RESULTS

The qRT-PCR assays showed significant downregulation of miR-494 (P < 0.05) and upregulation of CLPTM1L mRNA (P < 0.05), both of which were significantly associated with lymph node metastases (P < 0.05). High expression of miR-494 inhibited cell proliferation and invasion and promoted cell apoptosis (P < 0.05). The results also showed that CLPTM1L was a target of miR-494.

CONCLUSION

These results show that the expression of miR-494, which can regulate cell growth, invasion and apoptosis of ESCC cells by targeting CLPTM1L, is downregulated in ESCC tumor tissues. The miR-494-CLPTM1L pathway could be further exploited to develop a new approach to treat ESCC.

MiR-101 reverses the hypomethylation of the LMO3 promoter in glioma cells

LIM-only protein 3 (LMO3), a member of the LIM-only protein group, is a new DNA methylation gene that was identified in gliomas via the MeDIP-Chip in our previous study. In this study, we found that LIM-only protein 3 (LMO3) is hypomethylated and overexpressed in glioma cells and tissues. The overexpression of LMO3 was correlated with a poor prognosis in glioma patients, and LMO3 was indirectly inhibited by the tumor suppressor miR-101, which is a potential prognosis marker of gliomas. MiR-101 decreased the expression of LMO3 by reversing the methylation status of the LMO3 promoter and by inhibiting the presence of the methylation-related histones H3K4me2 and H3K27me3 and increasing the presence of H3K9me3 and H4K20me3 on the promoter. It was determined that miR-101 decreases the occupancy of H3K27me3 by inhibiting EZH2, DNMT3A and EED and decreases the H3K9me3 occupancy on the LMO3 promoter via SUV39H1, SUV39H2, G9a and PHF8. Furthermore, miR-101 suppresses the expression of LMO3 by decreasing USF and MZF1.