Purpose: Different microRNAs (miRs) have been demonstrated to relate with the outcome of glioma patients, while the conclusions are inconsistent. We perform a meta-analysis to clarify the relationship between different miRs and prognosis of glioma.
Methods: Related studies were retrieved from PubMed, Embase, and Cochrane Library. Pooled hazard ratios (HRs) of different miRs expression for survival and 95% confidence intervals (CIs) were calculated using random-effects model.
Results: A total of 15 miRs with 4708 glioma patients were ultimately included. Increased expression of miR-15b (HR, 1.584; 95% CI, 1.199-2.092), 21 (HR, 1.591; 95% CI, 1.278-1.981), 148a (HR, 1.122; 95% CI, 1.023-1.231), 196 (HR, 1.877; 95% CI, 1.033-3.411), 210 (HR, 1.251; 95% CI, 1.010-1.550), and 221 (HR, 1.269; 95% CI, 1.054-1.527) or decreased expression of miR-106a (HR, 0.809; 95% CI, 0.655-0.998) and 124 (HR, 0.833; 95% CI, 0.729-0.952) was correlated with poor outcome of glioma patients.
Conclusions: miR-15b, 21, 148a, 196, 210, 221, 106a, and 124 are valuable biomarkers for the prognosis of glioma which might be used in clinical settings.

Background: LIM kinase 1 (LIMK1) expression levels are closely associated with microRNA (miRNA) processing. Higher levels of LIMK1 are reported during the progression of many cancers. Our study explored the interaction between LIMK1 and miR-106a in oral squamous cell carcinoma (OSCC).
Methods: Quantitative RT-PCR was performed to detect the levels of LIMK1 and miR-106a in OSCC tissues and cell lines. The rates of cell proliferation and epithelial-mesenchymal transition (EMT) were assessed to determine the biological functions of miR-106a and LIMK1 in OSCC cells. The mRNA and protein levels of LIMK1 were measured using quantitative RT-PCR and western blotting. Luciferase assays were performed to validate LIMK1 as an miR-106a target in OSCC cells.
Results: We found that the level of miR-106a significantly decreased and the expression of LIMK1 significantly increased in OSCC tissues and cell lines. There was a close association between these changes. Knockdown of LIMK1 significantly inhibited the proliferation and EMT of OSCC cells. The bioinformatics analysis predicted that LIMK1 is a potential target gene of miR-106a and the luciferase reporter assay confirmed that miR-106a could directly target LIMK1. Introduction of miR-106a to OSCC cells had similar effects to LIMK1 silencing. Overexpression of LIMK1 in OSCC cells partially reversed the inhibitory effects of the miR-106a mimic.
Conclusion: MiR-106a inhibited the cell proliferation and EMT of OSCC cells by directly decreasing LIMK1 expression.

Wilms tumor gene on the X chromosome (WTX) is a putative tumor suppressor gene in Wilms tumor, but its expression and functions in other tumors are unclear. Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in women and the second leading cause in men in the United States. We demonstrated that WTX frequently lost in CRC which was highly correlated with cell proliferation, tumor invasion and metastasis. Mechanistically, WTX loss disrupts the interaction between RhoGDIα and CDC42 by losing of the binding with RhoGDIα and triggers the activation of CDC42 and its downstream cascades, which promotes CRC development and liver metastasis. The aberrant upregulation of miR-20a/miR-106a were identified as the reason of WTX loss in CRC both in vivo and in vitro. These study defined the mechanism how miR-20a/miR-106a-mediated WTX loss regulates CRC progression and metastasis, and provided a potential therapeutic target for preventing CRC progression.

To explore the effect of miR-106a in breast cancer cell behavior and sensitivity to chemotherapeutic agents. Tumor tissue and adjacent normal tissue were derived from 40 breast cancer patients, and miR-106a expression was measured by reverse transcription-qPCR. Breast cancer cells, MDA-MB-231 and MCF-7, were treated with miRNA-106a mimic (MM) or miRNA-106a inhibitor (MI) and negative controls. Cell proliferation was measured by MTT assay. Clonogenicity was measured by colony-forming assay. Cell migration and invasion ability were measured by scratch test and transwell assay, respectively. Apoptosis was determined by flow cytometry, and chemosensitivity to cisplatin was measured by MTT assay. Finally, protein expression of p53, Bax, Bcl-2, RUNX3, and ABCG2 was quantified by western blot. miR-106a expression was significantly upregulated in human breast cancer tissue relative to adjacent normal tissue. Upregulation of miR-106a enhanced breast cancer cell proliferation, colony-forming capacity, migration, and invasion of cultured breast cancer cells. Additionally, miR-106a overexpression significantly decreased breast cancer cell apoptosis and sensitivity to cisplatin. Finally, we showed miR-106a overexpression upregulated the levels of Bcl-2 and ABCG2, and downregulated the expression of P53, Bax, and RUNX3. miR-106a promotes breast cancer cell proliferation and invasion through upregulation of Bcl-2, ABCG2, and P53, and downregulation of Bax and RUNX3.

BACKGROUND: The use of biomarkers that allow early therapeutic intervention or intensive follow-up evaluation is expected to be a powerful means for reducing breast cancer mortality. MicroRNAs (miRNAs) are known to play major roles in cancer biology including metastasis. This study aimed to develop a novel miRNA risk score to predict patient survival and metastasis in breast cancer.
METHODS: An integrated unbiased approach was applied to derive a composite risk score for prognosis based on miRNA expression in primary breast tumors in 1051 breast cancer patients from The Cancer Genome Atlas (TCGA). Further analysis of the risk score with metastasis/recurrence was performed using the TCGA data set and validated in a separate patient population using small RNA sequencing.
RESULTS: The three-miRNAs risk score (miR-19a, miR-93, and miR-106a) was developed using the TCGA cohort, which predicted poor prognosis (p = 0.0005) independently of known clinical risk factors. The prognostic value was validated in another three following independent cohorts: GSE19536 (p = 0.0009), GSE22220 (p = 0.0003), and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (p = 0.0023). The three-miRNAs risk score predicted bone recurrence in TCGA (p = 0.0052), and the findings were validated in another independent population of patients who experienced bone recurrence and age/stage-matched patients without any recurrence. The three-miRNAs risk score enriched multiple metastasis-related gene sets such as angiogenesis and epithelial mesenchymal transition in a gene-set-enrichment analysis.
CONCLUSIONS: The authors developed the novel miRNA-based risk score, which is a promising biomarker for prediction of worse survival and bone recurrence potential in breast cancer.

BACKGROUND: Gastric cancer (GC) is a common malignancy and frequent cause of cancer-related death. Long non-coding RNAs (lncRNAs) have emerged as important regulators and tissue-specific biomarkers of multiple cancers, including GC. Recent evidence has indicated that the novel lncRNA LINC01133 plays an important role in cancer progression and metastasis. However, its function and molecular mechanism in GC remain largely unknown.
METHODS: LINC01133 expression was detected in 200 GC and matched non-cancerous tissues by quantitative reverse transcription PCR. Gain- and loss-of-function experiments were conducted to investigate the biological functions of LINC01133 both in vitro and in vivo. Insights into the underlying mechanisms of competitive endogenous RNAs (ceRNAs) were determined by bioinformatics analysis, dual-luciferase reporter assays, quantitative PCR arrays, TOPFlash/FOPFlash reporter assay, luciferase assay, and rescue experiments.
RESULTS: LINC01133 was downregulated in GC tissues and cell lines, and its low expression positively correlated with GC progression and metastasis. Functionally, LINC01133 depletion promoted cell proliferation, migration, and the epithelial-mesenchymal transition (EMT) in GC cells, whereas LINC01133 overexpression resulted in the opposite effects both in vitro and in vivo. Bioinformatics analysis and luciferase assays revealed that miR-106a-3p was a direct target of LINC01133, which functioned as a ceRNA in regulating GC metastasis. Mechanistic analysis demonstrated that miR-106a-3p specifically targeted the adenomatous polyposis coli (APC) gene, and LINC01133/miR-106a-3p suppressed the EMT and metastasis by inactivating the Wnt/β-catenin pathway in an APC-dependent manner.
CONCLUSIONS: Our findings suggest that reduced expression of LINC01133 is associated with aggressive tumor phenotypes and poor patient outcomes in GC. LINC01133 inhibits GC progression and metastasis by acting as a ceRNA for miR-106a-3p to regulate APC expression and the Wnt/β-catenin pathway, suggesting that LINC01133 may serve as a potential prognostic biomarker and anti-metastatic therapeutic target for GC.

MicroRNAs (miRs) serve an essential role in tumorigenesis and are able to act as tumor suppressor genes or oncogenes. miR‑106a has been identified generally as an oncogene in multiple types of human cancer; however, its association with osteosarcoma has not previously been understood. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to detect miR‑106a expression in 18 osteosarcoma tissues compared with paired non‑cancerous adjacent tissues as well as osteosarcoma cell lines (U2OS, Saos‑2 and MG63) compared with a normal osteoblast cell line (hFOB1.19). The biological function of U2OS cells was assessed by using a Transwell cell invasion assay, MTS proliferation assay and flow cytometric analysis following the transfection with lentivirus‑mediated small interfering RNA (miR‑106a‑inhibitor). Western blotting and Luciferase reporters were used to investigate whether VNN2 was a target of miR‑106a in osteosarcoma cells. Based on the RT‑qPCR data, miR‑106a was significantly upregulated in osteosarcoma tissues and osteosarcoma cell lines compared with their control counterparts (P<0.01). The knockdown of miR‑106a resulted in cell proliferation and invasion inhibition. Furthermore, apoptosis enhancement and G2/M cell cycle arrest were detected by flow cytometry. The western blot analysis indicated that U2OS cells infected with miR‑106a‑inhibitor lentivirus had a higher VNN2 protein expression level compared with cells infected with miR‑106a‑negative control lentivirus. Luciferase reporters containing the 3'‑untranslated region sequence of VNN2 messenger RNA demonstrated VNN2 may be a target of miR‑106a. In addition, a negative correlation was confirmed between the expression of VNN2 and miR‑106a in the tumor samples. The results of the present study indicate that the knockdown of miR‑106a overexpressed VNN2 to inhibiting the proliferation, migration and invasion as well as inducing the apoptosis of human osteosarcoma cells.

YAP1, a vital effector of Hippo pathway, promotes cancer development via transcriptionally regulating a batch of target genes involved in various signaling pathways, including proliferation, apoptosis, and cell drug sensitivity. Recently, circular RNAs (circRNAs) have been shown to control gene expression post-transcriptionally and become a new layer of gene regulation. However, whether circRNAs play roles in YAP1-induced tumorigenesis is still largely elusive. Here, we identify circRNA-000425 as a new inhibitory target of YAP1, and also find that it binds to miR-17/miR-106b, and thus suppresses cancer cell growth induced by these miRNAs. circRNA-000425 is revealed as a YAP1 target through circRNA microarray analysis of RNAs extracted from cells treated with or without YAP1 siRNAs, and further confirmed by RT-q-PCR and ChIP assays. Interestingly, bioinformatics analysis, luciferase assay, and RT-q-PCR results showed that circRNA-000425 binds to miR-17 and miR-106b, but not let-7a, and rescues the inhibitory effect of miR-17/miR-106 on the expressions of both p21 and BIM. In addition, colony formation and MTT assay showed that circRNA-000425 inhibits cancer cell growth induced by miR-17. These findings reveal a mechanism by which YAP1 promotes oncogenic activities of miR-17 and miR-106b through transcriptionally inhibiting circRNA-000425 expression.

BACKGROUND 5-Fluorouracil (5-FU)-based chemotherapy is a conventional therapeutic approach for the treatment of patients with colorectal cancer (CRC). However, development of 5-FU resistance frequently occurs. We explored a potential method for regulating the sensitivity to 5-FU-based chemotherapy in CRC patients. MATERIAL AND METHODS Cell viability was determined by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Gene expression levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Protein expression levels were evaluated by Western blot. TargetScan was used for the prediction of binding sites for miRNA in mRNAs. The interaction between mRNA 3'UTR and miRNA was verified by dual luciferase reporter assay. Tissue samples were obtained from 33 CRC patients who received surgery at Xingtai People's Hospital. RESULTS miR-106a level was associated with 5-FU sensitivity in CRC cells. Overexpression of miR-106a reduced 5-FU sensitivity of HCT116 and SW620 cells, and antagonist of miR-106a sensitized HCT116 and SW620 towards 5-FU. miR-106a overexpression decreased dual-specificity phosphatases 2 (DUSP2) expression at mRNA and protein levels in HCT116 and SW620 cells. Through downregulation of DUSP2, miR-106a elevation increased COX-2 expression and stemness-maintenance genes (SOX2 and OCT4). Furthermore, we predicted that miR-106a directly binds to 3'UTR of DUSP2 mRNA, which was confirmed by dual luciferase assay. Silencing of DUSP2 reversed elevated 5-FU sensitivity induced by miR-106a antagonist in HCT116 cells. A negative correlation was discovered between miR-106a and DUSP2 in tumor samples of CRC patients. CONCLUSIONS miR-106a plays an important role in mediating response to 5-FU-based chemotherapy in CRC and could serve as a potential target for CRC patients.

Prostate carcinoma contain foci of neuroendocrine transdifferentiation, resulting in an increase of androgen-independent neuroendocrine-like (NE) tumor cells, whose number significantly correlates with tumor aggressiveness and thus lower survival rate. Neuroendocrine transdifferentiation of prostate cancer cells and a potential role of miRNAs within this process are poorly understood. MicroRNAs are small non-coding RNAs which post-transcriptionally regulate gene expression. The aim of this project was to identify new genes and miRNAs involved in neuroendocrine transdifferentiation. LNCaP prostate cancer cells were differentiated to NE-like cancer cells and microarray analyses were performed. Microarray results have been validated for the eight most deregulated mRNAs and microRNAs via qRT-PCR and analyzed with different algorithms to predict new targets for deregulated microRNAs. The induced CyclinD1 gene could be validated as new target gene for the repressed miR-17 family containing miR-17, miR-20a, miR-20b, miR-106a and miR-106b via reporter gene assays and Western Blot. Functional analysis of miR-17 family shows a high influence on cell proliferation, colony forming ability and apoptosis in LNCaP cells. Our data demonstrate wide changes in mRNA and microRNA expression during neuroendocrine transdifferentiation of LNCaP cells and confirm new mRNA-miRNA interactions with potential roles in NE-transdifferentiation of prostate carcinoma.

Bladder cancers can be categorized into subtypes according to gene expression patterns. P53-like muscle-invasive bladder cancers are generally resistant to cisplatin-based chemotherapy, but exhibit heterogeneous clinical outcomes with a prognosis intermediate to that of the luminal and basal subtypes. The optimal approach to p53-like tumors remains poorly defined and better means to risk-stratify such tumors and identification of novel therapeutic targets is urgently needed. MicroRNAs (miRNAs) play a key role in cancer, both in tumorigenesis and tumor progression. In the past few years, miRNA expression signatures have been reported as prognostic biomarkers in different tumor types including bladder cancer. However, miRNA's expression does not always correlate well with its activity. We previously developed ActMiR, a computational method for explicitly inferring miRNA activities. We applied ActMiR to The Cancer Genome Atlas (TCGA) bladder cancer data set and identified the activities of miR-106b-5p and miR-532-3p as potential prognostic markers of the p53-like subtype, and validated them in three independent bladder cancer data sets. Especially, higher miR-106b-5p activity was consistently associated with better survival in these data sets. Furthermore, we experimentally validated causal relationships between miR-106-5p and its predicted target genes in p53-like cell line HT1197. HT1197 cells treated with the miR-106b-5p-specific inhibitor were more invasive while cells treated with the miR-106b-5p-specific mimic were less invasive than corresponding controls. Altogether, our results suggest that miR-106b-5p activity can categorize p53-like bladder tumors into more and less-favorable prognostic groups, which provides critical information for personalizing treatment option for p53-like bladder cancers.

BACKGROUND: MicroRNAs are classes of endogenous noncoding RNAs that play a substantial role in tumor processes through regulating the targets at posttranscriptional level. However, little is known about the upstream transcription regulatory mechanism although it is a prerequisite for investigation of its aberrant expression and function.
AIMS: This report evaluates miR-106a's direct transcriptional factor from upstream level to in depth elucidate their communication in gastric cancer development.
METHODS: Gastric cancer tissues were collected to analyze the miR-106a expression using real-time PCR methods. The combination of Kruppel (or Krüppel)-like factor 4 (KLF4) to miR-106a promoter was testified through bioinformatics followed by construction of luciferase reporter plasmid and chromatin immunoprecipitation assay. Functional experiments and mouse models for evaluating cell growth and metastasis were conducted to observe the biological effect of KLF4 on miR-106a. The interplay between KLF4 and miR-106a was tested with Wnt activator and confirmed in clinical specimens.
RESULTS: The up-regulated miR-106a linked to gastric cancer metastasis and epithelial-mesenchymal transition. UCSC and JASPAR predicted the promoter sequence of miR-106a and its binding site with transcriptional factor KLF4. Construction of reporter gene further verified their direct combination at upstream level. Moreover, the inhibitory effect of KLF4 on the phenotype of gastric cancer cells could be restored by miR-106a. CHIR-induced experiment and clinical specimens confirmed the negative regulation of KLF4 on miR-106a.
CONCLUSIONS: Our findings provide novel direct insights into molecular mechanisms for interaction of KLF4 and miR-106a at upstream level and new ways for clinical application of KLF4-miR-106a axis in advanced gastric cancer metastasis.

BACKGROUND: Invasive cervical cancer (ICC) is caused by high-risk human papillomavirus types (HR-HPVs) and is usually preceded by a long phase of intraepithelial neoplasia (CIN). Before invasion, (epi) genetic changes, potentially applicable as molecular markers within cervical screening, occur in HPV host cells. Epigenetic alterations, such as dysregulation of microRNA (miRNA) expression, are frequently observed in ICC. The mechanisms and role of miRNA dysregulation in cervical carcinogenesis are still largely unknown.
METHODS: We provide an overview of the studies investigating miRNA expression in relation to ICC progression, highlighting their common outcomes and their weaknesses/strengths. To achieve this, we systematically searched through Pubmed database all articles between January 2010 and December 2017.
RESULTS: From the 24 studies retrieved, miR-29a and miR-21 are the most frequently down- and up-regulated in ICC progression, respectively. Microarray-based studies show a small overlap, with miR-10a, miR-20b, miR-9, miR-16 and miR-106 found repeatedly dysregulated. miR-34a, miR-125 and miR-375 were also found dysregulated in cervical exfoliated cells in relation to cancer progression.
CONCLUSIONS: The pivotal role of miRNAs in ICC progression and initial development is becoming more and more relevant. Available studies are essentially based on convenience material, entailing possible selection bias, and frequently of small size: all these points still represent a limitation to a wide comprehension of miRNAs relevant for ICC. The targeted approach instead of a genome-wide investigation still precludes the identification of all the relevant miRNAs in the process. The implementation of deep sequencing on large scale population-based studies will help to discover and validate the relation between altered miRNA expression and CC progression for the identification of biomarkers. Optimally, once explored on a miRNome scale, small specific miRNA signatures maybe used in the context of screening.

Recurrence of high-grade prostate cancer after radiotherapy is a significant clinical problem, resulting in increased morbidity and reduced patient survival. The molecular mechanisms of radiation resistance are being elucidated through the study of microRNA (miR) that negatively regulate gene expression. We performed bioinformatics analyses of The Cancer Genome Atlas (TCGA) dataset to evaluate the association between miR-106a and its putative target lipopolysaccharide-induced TNF-α factor (LITAF) in prostate cancer. We characterized the function of miR-106a through in vitro and in vivo experiments and employed transcriptomic analysis, western blotting, and 3'UTR luciferase assays to establish LITAF as a bona fide target of miR-106a. Using our well-characterized radiation-resistant cell lines, we identified that miR-106a was overexpressed in radiation-resistant cells compared to parental cells. In the TCGA, miR-106a was significantly elevated in high-grade human prostate tumors relative to intermediate- and low-grade specimens. An inverse correlation was seen with its target, LITAF. Furthermore, high miR-106a and low LITAF expression predict for biochemical recurrence at 5 years after radical prostatectomy. miR-106a overexpression conferred radioresistance by increasing proliferation and reducing senescence, and this was phenocopied by knockdown of LITAF. For the first time, we describe a role for miRNA in upregulating ATM expression. LITAF, not previously attributed to radiation response, mediates this interaction. This route of cancer radioresistance can be overcome using the specific ATM kinase inhibitor, KU-55933. Our research provides the first report of miR-106a and LITAF in prostate cancer radiation resistance and high-grade disease, and presents a viable therapeutic strategy that may ultimately improve patient outcomes.

BACKGROUND: Recently, accumulating evidences have revealed that microRNA-106 (miR-106) may serve as a non-invasive and cost-effective biomarker in gastric cancer (GC) detection. However, inconsistent results have prevented its application to clinical practice.
METHODS: As a result of this, a comprehensive meta-analysis was conducted to evaluate the diagnostic performance of miR-106 alone and miR-106-related combination markers for GC detection. Meanwhile, an integrative bioinformatics analysis was performed to explore the function of miR-106 at the systems biology level.
RESULTS: The results in our work showed that sensitivity of 0.71 (95% CI 0.65-0.76) and specificity of 0.82 (0.72-0.88), with the under area AUC (area under the curve) value of 0.80 (0.76-0.83) for miR-106 alone. Prospectively, miR-106-related combination markers improved the combined sensitivity, specificity and AUC, describing the discriminatory ability of 0.78 (0.65-0.87), 0.83 (0.77-0.89) and 0.88 (0.85-0.90) in the present analysis. Furthermore, targets of miR-106 were obtained and enriched by gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, revealing their associations with the occurrence and development of GC. Hub genes and significant modules were identified from the protein-protein interaction networks constructed by miR-106 targets and found closely associated with the initiation and progression of GC again.
CONCLUSIONS: Our comprehensive and integrative analysis revealed that miR-106 may be suitable as a diagnostic biomarker for GC while microRNA combination biomarkers may provide a new alternative for clinical application. However, it is necessary to conduct large-scale population-based studies and biological experiments to further investigate the diagnostic value of miR-106.

MicroRNA-20b-5p (miR-20b-5p) is part of the miR-106a/363 cluster and a member of the cancer-related miR-17 family. miR-20b-5p regulates important transcription factors, including hypoxia-inducible factor 1 (HIF1) and signal transducer and activator of transcription 3 (STAT3). Recently, the dysregulation of miR-20b-5p expression has been observed in many B-cell lymphomas and T-cell leukemias. In this research study, we examined the putative prognostic value of miR-20b-5p in CLL. Therefore, total RNA was isolated from peripheral blood mononuclear cells (PBMCs) collected from 88 CLL patients; next, total RNA was polyadenylated and first-strand cDNA was synthesized, using an oligo-dT-adapter primer. miR-20b-5p expression was quantified using an in-house-developed real-time quantitative PCR assay. Kaplan-Meier OS analysis and bootstrap univariate Cox regression showed that high miR-20b-5p expression predicts better OS for CLL patients (p < 0.001). Interestingly, miR-20b-5p overexpression retains its favorable prognostic role in CLL patients of intermediate risk or stratified according to established prognostic factors [CD38 expression and mutational status of the immunoglobulin heavy chain variable (IGHV) region]. In conclusion, miR-20b-5p is a potential independent molecular biomarker of favorable prognosis in CLL.

By routinely and systematically being able to perform quantitative stem-loop reverse transcriptase (RT) followed by TaqMan® minor-groove binding (MGB) probe, real-time quantitative PCR analysis on exfoliated enriched colonocytes in stool, using human (Homo sapiens, hsa) micro(mi)RNAs to monitor changes of their expression at various stages of colorectal (CRC) progression, this method allows for the reliable and quantitative diagnostic screening of colon cancer (CC). Although the expression of some miRNA genes tested in tissue shows less variability in normal or cancerous patients than in stool, the noninvasive stool by itself is well suited for CC screening. An miRNA approach using stool promises to offer more sensitivity and specificity than currently used genomic, methylomic, or proteomic methods for CC screening.To present an application of employing miRNAs as diagnostic markers for CC screening, we carried out global microarray expression studies on stool colonocytes isolated by paramagnetic beads, using Affymetrix GeneChip miRNA 3.0 Array, to select a panel of miRNAs for subsequent focused semiquantitative PCR analysis studies. We then conducted a stem-loop RT-TaqMan® MGB probes, followed by a modified real-time qPCR expression study on 20 selected miRNAs for subsequent validation of the extracted immunocaptured total small RNA isolated from stool colonocytes. Results showed 12 miRNAs (miR-7, miR-17, miR-20a, miR-21, miR-92a, miR-96, miR-106a, miR-134, miR-183, miR-196a, miR-199a-3p, and miR214) to have an increased expression in stool of CC patients, and that later TNM stages exhibited more increased expressions than adenomas, while 8 miRNAs (miR-9, miR-29b, miR-127-5p, miR-138, miR-143, miR-146a, miR-222, and miR-938) showed decreased expressions in stool of CC patients, which becomes more pronounced as the cancer progresses from early to late TNM stages (0-IV).

PURPOSE: Novel noninvasive biomarkers with high sensitivity and specificity for the diagnosis of breast cancer (BC) are urgently needed in clinics. The aim of this study was to explore whether miRNAs from the miR-106a-363 cluster can be detected in the circulation of BC patients and whether these miRNAs can serve as potential diagnostic biomarkers.
METHODS: The expression of 12 miRNAs from the miR-106a-363 cluster was evaluated using qRT-PCR in 400 plasma samples (from 200 BC patients and 200 healthy controls (HCs)) and 406 serum samples (from 204 BC patients and 202 HCs) via a three-phase study. The identified miRNAs were further examined in tissues (32 paired breast tissues), plasma exosomes (from 32 BC patients and 32 HCs), and serum exosomes (from 32 BC patients and 32 HCs).
RESULTS: Upregulated levels of four plasma miRNAs (miR-106a-3p, miR-106a-5p, miR-20b-5p, and miR-92a-2-5p) and four serum miRNAs (miR-106a-5p, miR-19b-3p, miR-20b-5p, and miR-92a-3p) were identified and validated in BC. A plasma 4-miRNA panel and a serum 4-miRNA panel were constructed to discriminate BC patients from HCs. The areas under the receiver-operating characteristic curves of the plasma panel were 0.880, 0.902, and 0.858, and those of the serum panel were 0.910, 0.974, and 0.949 for the training, testing, and external validation phases, respectively. Two overlapping miRNAs (miR-106a-5p and miR-20b-5p) were consistently upregulated in BC tissues. Except for the expression of the plasma-derived exosomal miR-20b-5p, the expression patterns of exosomal miRNAs were concordant between plasma and serum, indicating the potential use of exosomal miRNAs as biomarkers.
CONCLUSION: We identified four plasma miRNAs and four serum miRNAs from the miR-106a-363 cluster as promising novel biomarkers for the diagnosis of BC.

The fundamental function of ribonucleic acids is to transfer genetic information from DNA to protein during translation process, however, this is not the only way connecting active RNA sequences with essential biological processes. Up until now, many RNA subclasses of different size, structure, and biological function were identified. Among them, there are non-coding single-stranded microRNAs (miRNAs). This subclass comprises RNAs of 19-25 nucleotides in length that modulate the activity of well-defined coding RNAs and play a crucial role in many physiological and pathological processes. miRNA genes are located both in exons, introns, and also within non-translated regions. Several miRNAs that are transcribed from the adjacent miRNA genes are called cluster. One of the largest ones is miR-17-92 cluster known as OncomiR-1 due to its strong link to oncogenesis. Six miRNAs from the OncomiR-1 have been shown to play important roles in various physiological cellular processes but also through inhibition of cell death in many cancer-relevant processes. Due to the origin and similarity of the sequence, miR-17-92 cluster and paralogs, miR-106b-25 and miR-106a-363 clusters were defined. Here we discuss the oncogenic function of those miRNA subgroups found in many types of cancers, including brain tumors.

BACKGROUND/AIM: To date, the combination of gastroscopy with biopsy remains the only test validated for screening gastric cancer (GC). Currently, analysis of circulating microRNAs (miRNAs or miRs) is providing interesting information on GC prognosis, but since these molecules are shared by several types of cancer, its clinical use could be questionable and difficult. MicroRNAs in gastric juice (GJ) could represent a cogent alternative to screening GC by biopsy.
MATERIALS AND METHODS: We investigated the pertinent literature dealing with GC GJ microRNAs through four popular search engines (PubMed, Science Direct, Scopus and Google Scholar).
RESULTS: As of 2017, only four studies had been published and were all from Chinese experience. MiR-421, miR-129, miR-21, miR-106a and miR-133a were the five molecules studied in the GJ of the enrolled patients.
CONCLUSION: The GJ miRNA test is reliable and reproducible. The discussed GJ miRNAs appear to be new potential biomarkers for the screening of GC.

PURPOSE: lncRNA H19 has been considered as an oncogenic lncRNA in many human tumours. In the present study, we identify the role and molecular mechanism of lncRNA H19 in melanoma.
METHOD: QRT-PCR was used to detect the expression of lncRNA H19 and E2F3 was detected in melanoma tissues. Cell counting kit-8 (CCK8), representative metabolites analysis was used to explore the biological function of lncRNA H19, miR-106a-5p and E2F3 in melanoma cells. Bioinformatics, luciferase reporter assays, MS2-RIP and RNA pull-down assay was used to demonstrate the molecular mechanism of lncRNA H19 in melanoma. We further test the function of lncRNA H19 in vivo though Xenograft tumour assay.
RESULTS: We found that lncRNA H19 was increased in melanoma tissue, and lncRNA H19 was correlated with poor prognosis of melanoma patients. miR-106a-5p acts as a tumour suppressor in melanoma by targeting E2F3. E2F3 affects the melanoma cell glucose metabolism and growth. We also demonstrated that lncRNA H19 may function as the sponge of miR-106a-5p to up-regulate E2F3 expression, and consequently promote the glucose metabolism and growth of melanoma.
CONCLUSIONS: This result elucidates a new mechanism for lncRNA H19 in melanoma development and provides a survival indicator and potential therapeutic target for melanoma patients.

HIF-2α knockdown inhibits proliferation, arrests the cell cycle, and promotes apoptosis and autophagy under hypoxic conditions in cervical cancer. However, the upstream regulatory mechanism of HIF-2α expression is unclear. MicroRNAs (miRNAs) degrade target mRNAs by binding to the 3'-untranslated region of mRNAs. In this study, we investigated the role of miRNAs in the regulation of HIF-2α expression in cervical cancer under hypoxic conditions. miRNAs regulating HIF-2α expression were predicted using TargetScan and miRanda and were determined in cervical cancer under hypoxic conditions by qRT-PCR. Additionally, the targeted regulation of HIF-2α by miR-519d-3p was evaluated by Western blot and luciferase reporter assays. Effects of miR-519d-3p and HIF-2α on cell proliferation, cell cycle, and apoptosis were analyzed by CCK-8 and flow cytometry assays, respectively. miR-106a-5p, miR-17-5p, miR-519d-3p, miR-526b-3p, and miR-20b-5p are potentially regulatory miRNAs that bound to the HIF-2α 3'-untranslated region as per TargetScan and miRanda predictions. Expression of the five miRNAs was inhibited in HeLa cells under hypoxic conditions compared to normoxic conditions, and the expression of miR-519d-3p was lower than that of other miRNAs. Luciferase reporter assays showed that HIF-2α was a target of miR-519d-3p. Additionally, miR-519d-3p overexpression inhibited cell proliferation, arrested the cell cycle transition from the G1 stage to the S stage, and promoted cell apoptosis under hypoxic conditions in cervical cancer. HIF-2α overexpression partially reversed the effect of miR-519d-3p. In conclusion, miR-519d-3p overexpression suppressed proliferation, inhibited the cell cycle, and promoted apoptosis of HeLa cells by targeting HIF-2α under hypoxic conditions.

MicroRNA dysregulation is a common feature of cancer and due to the promiscuity of microRNA binding this can result in a wide array of genes whose expression is altered. miR-106b is an oncomiR overexpressed in cholangiocarcinoma and its upregulation in this and other cancers often leads to repression of anti-tumorigenic targets. The goal of this study was to identify the miR-106b-regulated gene landscape in cholangiocarcinoma cells using a genome-wide, unbiased mRNA analysis. Through RNA-Seq we found 112 mRNAs significantly repressed by miR-106b. The majority of these genes contain the specific miR-106b seed-binding site. We have validated 11 genes from this set at the mRNA level and demonstrated regulation by miR-106b of 7 proteins. Combined analysis of our miR-106b-regulated mRNA data set plus published reports indicate that miR-106b binding is anchored by G:C pairing in and near the seed. Novel targets Kruppel-like factor 2 (KLF2) and KLF6 were verified both at the mRNA and at the protein level. Further investigation showed regulation of four other KLF family members by miR-106b. We have discovered coordinated repression of multiple members of the KLF family by miR-106b that may play a role in cholangiocarcinoma tumor biology.

MicroRNA-106a-5p (MiR-106a-5p), a small non-coding RNA, has been reported to be downregulated in astrocytoma, osteosarcoma and colorectal cancer. However, the expression levels and biological function in renal cell carcinoma (RCC) have not been studied yet. In this study, we found that the miR-106a-5p was significantly downregulated in RCC tissues and cell lines, and that overexpression of miR-106a-5p led to decreased cell metastasis ability in a xenograft model. Inhibition of miR-106a-5p in RCC cell lines altered the cell migration, invasion and wound healing abilities. Mechanistic studies demonstrated that miR-106a-5p directly bound to the 3'-UTR of the PAK5 mRNA and mediated a decrease in the protein expression of PAK5. We further proved that PAK5 protein levels were negatively correlated with the miR-106a-5p expression in both patient samples and xenograft model. In epigenetics, methylation specific PCR experiments indicated that the upstream gene promoter of miR-106a-5p was hypermethylated in RCC, which might be responsible for its downregulation. Our findings suggested that miR-106a-5p might be a potential gene therapy target for the treatment of RCC metastasis.

Purpose Children with acute myeloid leukemia (AML) whose disease is refractory to standard induction chemotherapy therapy or who experience relapse after initial response have dismal outcomes. We sought to comprehensively profile pediatric AML microRNA (miRNA) samples to identify dysregulated genes and assess the utility of miRNAs for improved outcome prediction. Patients and Methods To identify miRNA biomarkers that are associated with treatment failure, we performed a comprehensive sequence-based characterization of the pediatric AML miRNA landscape. miRNA sequencing was performed on 1,362 samples-1,303 primary, 22 refractory, and 37 relapse samples. One hundred sixty-four matched samples-127 primary and 37 relapse samples-were analyzed by using RNA sequencing. Results By using penalized lasso Cox proportional hazards regression, we identified 36 miRNAs the expression levels at diagnosis of which were highly associated with event-free survival. Combined expression of the 36 miRNAs was used to create a novel miRNA-based risk classification scheme (AMLmiR36). This new miRNA-based risk classifier identifies those patients who are at high risk (hazard ratio, 2.830; P ≤ .001) or low risk (hazard ratio, 0.323; P ≤ .001) of experiencing treatment failure, independent of conventional karyotype or mutation status. The performance of AMLmiR36 was independently assessed by using 878 patients from two different clinical trials (AAML0531 and AAML1031). Our analysis also revealed that miR-106a-363 was abundantly expressed in relapse and refractory samples, and several candidate targets of miR-106a-5p were involved in oxidative phosphorylation, a process that is suppressed in treatment-resistant leukemic cells. Conclusion To assess the utility of miRNAs for outcome prediction in patients with pediatric AML, we designed and validated a miRNA-based risk classification scheme. We also hypothesized that the abundant expression of miR-106a could increase treatment resistance via modulation of genes that are involved in oxidative phosphorylation.

Epigenetics have been demonstrated to play a pivotal role in the progression of multiple cancers. Our previous study has demonstrated that microvesicles (MVs) derived from K562 cells could malignantly transform normal hematopoietic cells. The aim of this section was to elucidate the epigenetic effects of RNA in K562-MVs. We altered some epigenetic RNAs (miR-106a-5p, miR-106b-5p and lincPOU3F3) in K562-MVs and followed the process of transformation. Global DNA methylation and DNA methyltransferase (DNMT) levels were observed respectively. Our findings revealed that increased miR-106a/b in K562-MVs accelerated the transformation process (8.33±0.94 vs. 13.29±1.28 days; P<0.01) whereas decreased lincPOU3F3 delayed the transformation (17.83±0.29 days; P<0.05). The targets of miR-106a/b and lincPOU3F3 in the recipient cells were DNMT3a and DNMT3b. We found that lincPOU3F3 directly increased the DNMT3a/b while miR-106a/b only in part by targeting RB. However, global DNA methylation and special gene methylation was altered due to the concurrent regulation of DNMT3a and DNMT3b. Consequently, we demonstrated that tumor-derived MVs represent a notable intercellular epigenetic communication between cancer cells and recipient cells.

The findings from several studies have suggested that circulating miRNAs are imbalanced with the genesis of gastric cancer (GC). Both normal and cancer cells can generate and secrete exosomes, which are nanosized membrane vesicles that can transport microRNAs and proteins. Emerging evidence indicates that the exosomes secreted by cancer cells can be released into the circulatory system. In this study, we investigated whether circulating exosomal miRNAs can be used to discriminate individuals with GC from healthy controls (NCs). Based on the quantitative reverse transcription polymerase chain reaction (qRT-PCR), four miRNAs (miR-19b-3p, miR-17-5p, miR-30a-5p, and miR-106a-5p) related to GC pathogenesis were identified in serum-circulating exosomes from a cohort of 20 healthy controls and 20 individuals with GC in the initial screening phase. The distinguished miRNAs were further validated in the training (90 GC vs. 90 NCs) and blinded phases 20 GC vs. 20 NCs), and the area under receiver operating characteristic (ROC) curves of these miRNAs were analyzed. We found that miR-19b and miR-106a were markedly overexpressed in individuals with GC compared to NCs (P < 0.0001). Besides, the ROC analyses yielded the AUC values of 0.786 for miR-106a-5p, 0.769 for miR-19b-3p and combined ROC analysis revealed the highest AUC value of 0.814 in discriminating GC patients from NCs. Furthermore, based on the model developed from the data, a signature composed of the 2 miRNAs (miR-19b-3p and miR-106a-5p) correctly discriminated 19 out of 20 GC serum samples (95% sensitivity) and 18 out of 20 normal samples (90% specificity) in the blinded phase. Moreover, the validated miRNAs were related to GC lymphatic metastasis (P < 0.01) and expressed at higher levels in stages III and IV compared to I and II stages (P < 0.05). These results suggest that serum exosomal miR-19b-3p and miR-106a-5p are novel potential biomarkers for detecting GC.

Previous study has identified the aberrant expression of LINC00657, a long non-coding RNA (lncRNA), in human breast cancer. However, the expression pattern, biological function and underlying mechanism of LINC00657 in human hepatocellular carcinoma (HCC) remain obscure. The expression levels of LINC00657 in HCC tissues and cell lines were determined by quantitative real-time PCR. CCK-8 assay, cell colony formation assay, cell cycle analysis, Transwell assay were performed to determine whether LINC00657 could affect HCC progression. Luciferase reporter assay was used to assess the target of LINC00657. Expressions of the relevant proteins were analyzed by Western blot. Herein, we found that LINC00657 was downregulated in HCC tissue specimens as well as in malignant HCC cell lines. LINC00657 overexpression inhibited the proliferation, migration and invasion of HCC cells, while LINC00657 depletion promoted both cell viability and cell invasion in vitro. We also found that LINC00657 could inhibit tumor growth in vivo. Further experiments demonstrated that down-regulated LINC00657 increased the expression of miR-106a-5p. miR-106a-5p decreased the abundances of PTEN protein, while had no impact on PTEN mRNA. Moreover, we identified that both LINC00657 and PTEN mRNA were targets of miR-106a-5p by using dual-luciferase reporter assay. Our results provide the new evidence supporting the tumor-suppressive role of LINC00657 in HCC, suggesting that LINC00657 might play a role in HCC and can be a novel therapeutic target for treating HCC.

Earlier diagnosis and longitudinal monitoring of diffuse low-grade gliomas (DLGG) increase overall survival by maximizing surgery efficacy and optimizing time for an adjuvant treatment when resection is incomplete. Presently, only imaging permits the non-invasive detection and monitoring of DLGG, but it lacks sensitivity. Measure of circulating microRNAs levels could represent a non-invasive alternative. We hypothesized that slow-growing DLGG induce overtime a systemic reaction impacting blood cells microRNA profiles, while the intact blood-brain barrier restricts the passage of tumor microRNAs into bloodstream. In 15 DLGG patients and 15 healthy controls, expression levels of 758 microRNAs were measured by the TaqMan OpenArray RT-qPCR platform, on preoperative whole blood, containing both cell-free and blood cells microRNAs. Normalized data were computed by a Student t test with a p value threshold allowing a 10% rate of false positive. Statistical analysis retained fifteen microRNAs, all overexpressed in patients. MiR-20a, miR-106a, miR-20b, and miR-93 belong to clusters genetically related. As miR-223 and miR-let7e, they target the transcription factor STAT3. MicroRNA expression levels were not correlated to preoperative tumor volume. A signature composed of miR-93, miR-590-3p, and miR-454 enabled to nearly perfectly separate patients from controls. Our study performed on a homogeneous cohort was designed accordingly to DLGG particularities and provided the first microRNAs signature proposal. Functional convergence on STAT3 and overexpression of miR-223, factors respectively involved in myeloid-derived suppressor cells and granulocytes, argued for a systemic peripheral response. Overexpressed microRNAs and tumor volume were uncorrelated, making a tumor origin elusive.

Long non-coding RNAs (lncRNAs) are aberrantly expressed in various cancers. Fer-1-like protein 4 (FER1L4), one of lncRNAs, plays a role as tumor suppressor in various human cancers and can be regulated by microRNA. However, the role and function of FER1L4 in human hepatocellular carcinoma (HCC) remains unknown. The aim of the present study was to annotate the role of FER1L4 and its clinical value in HCC. In the present study, we found that FER1L4 was lowly expressed in HCC tissue specimens as well as in malignant HCC cell lines, while the situation is opposite in miR-106a-5p. We found that down-regulated FER1L4 increased the expression of miR-106a-5p significantly and there was a reciprocal repression between FER1L4 and miR-106a-5p. Moreover, we identified FER1L4 as a target of miR-106a-5p by using dual-luciferase reporter assay. Knockdown of FER1L4 promoted the malignancy of HCC cells, including proliferation, migration, and invasion, and inhibited cell apoptosis. We also found that FER1L4 functions as a tumor suppressor in vivo. Together, these results suggest that FER1L4 could exert a tumor suppressive impact on HCC, which at least, in part, through suppressing miR-106a-5p expression. FER1L4, as well as miR-106a-5p, can predict the clinical prognosis of HCC alone or combined, which may be a novel therapeutic target for treating HCC.