The role of microRNAs in nasopharyngeal carcinoma

Short 2'-O-methyl/LNA oligomers as highly-selective inhibitors of miRNA production in vitro and in vivo

MicroRNAs (miRNAs) that share identical or near-identical sequences constitute miRNA families and are predicted to act redundantly. Yet recent evidence suggests that members of the same miRNA family with high sequence similarity might have different roles and that this functional divergence might be rooted in their precursors' sequence. Current knock-down strategies such as antisense oligonucleotides (ASOs) or miRNA sponges cannot distinguish between identical or near identical miRNAs originating from different precursors to allow exploring unique functions of these miRNAs. We here develop a novel strategy based on short 2'-OMe/LNA-modified oligonucleotides to selectively target specific precursor molecules and ablate the production of individual members of miRNA families in vitro and in vivo. Leveraging the highly conserved Xenopus miR-181a family as proof-of-concept, we demonstrate that 2'-OMe/LNA-ASOs targeting the apical region of pre-miRNAs achieve precursor-selective inhibition of mature miRNA-5p production. Furthermore, we extend the applicability of our approach to the human miR-16 family, illustrating its universality in targeting precursors generating identical miRNAs. Overall, our strategy enables efficient manipulation of miRNA expression, offering a powerful tool to dissect the functions of identical or highly similar miRNAs derived from different precursors within miRNA families.

Regulatory role of miRNAs in nasopharyngeal cancer involving PTEN/PI3K/AKT, TGFβ/SMAD, RAS/MAPK, Wnt/β-catenin and pRB-E2F signaling pathways: A review

MicroRNAs (miRNA) are small and conserved noncoding RNA molecules that regulate gene expression at the posttranscriptional level. These groups of RNAs are crucial in various cellular processes, especially in mediating disease pathogenesis, particularly cancer. The dysregulation of miRNAs was reported in many cancer types, including nasopharyngeal cancer (NPC), which is a malignant tumor of the nasopharynx. In this review, miRNAs involvement in crucial signaling pathways associated with NPC such as PTEN/PI3K/AKT, TGFβ/SMAD, RAS/MAPK, Wnt/β-catenin and pRB-E2F was investigated. miRNAs could function as tumor suppressor-miR or onco-miR in NPC profoundly influenced cell cycle, apoptosis, proliferation, migration, and metastasis. This comprehensive review of current literature provided a thorough profile of miRNAs and their interplay with the aforementioned signaling pathways in NPC. Understanding these molecular interactions could remarkably impact the diagnosis, prognosis, and therapeutic strategies for NPC.

Unfolding the Complexity of Exosome-Cellular Interactions on Tumour Immunity and Their Clinical Prospects in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy situated in the posterolateral nasopharynx. NPC poses grave concerns in Southeast Asia due to its late diagnosis. Together with resistance to standard treatment combining chemo- and radiotherapy, NPC presents high metastatic rates and common recurrence. Despite advancements in immune-checkpoint inhibitors (ICIs) and cytotoxic-T-lymphocytes (CTLs)-based cellular therapy, the exhaustive T cell profile and other signs of immunosuppression within the NPC tumour microenvironment (TME) remain as concerns to immunotherapy response. Exosomes, extracellular vesicles of 30-150 nm in diameter, are increasingly studied and linked to tumourigenesis in oncology. These bilipid-membrane-bound vesicles are packaged with a variety of signalling molecules, mediating cell-cell communications. Within the TME, exosomes can originate from tumour, immune, or stromal cells. Although there are studies on tumour-derived exosomes (TEX) in NPC and their effects on tumour processes like angiogenesis, metastasis, therapeutic resistance, there is a lack of research on their involvement in immune evasion. In this review, we aim to enhance the comprehension of how NPC TEX contribute to cellular immunosuppression. Furthermore, considering the detectability of TEX in bodily fluids, we will also discuss the potential development of TEX-related biomarkers for liquid biopsy in NPC as this could facilitate early diagnosis and prognostication of the disease.

Aberrant miR-874-3p/leptin/EGFR/c-Myc signaling contributes to nasopharyngeal carcinoma pathogenesis

Background

Leptin is important in physiological and pathological functions in various cancers, however, the significance and mechanisms of leptin in nasopharyngeal carcinoma remain ambiguous.

Methods

Leptin expression was analyzed by QPCR, immunohistochemistry, Western blotting, and TCGA database. The impact of gain- or loss-of-function of leptin were determined by MTT, colony formation, wound healing, and Transwell assays in NPC cells, and by a xenograft tumor model. Leptin-modulated glucose consumption and lactate production were assessed by ELISA. Furthermore, leptin-regulated signaling pathways were examined by QPCR and Western blotting assays. The immunoprecipitation assay was conducted to determine interaction between leptin and EGFR. In addition, miR-874-3p-regulated leptin expression was evaluated using bioinformatics, QPCR, luciferase assay, AGO2-RIP assay, and Western blotting.

Results

In this study, we found that leptin was highly expressed in the sera and tumor tissues of patients with NPC, and elevated leptin expression was associated with advanced clinical features and poor prognosis. Functional assays demonstrated that leptin remarkably promoted NPC cell growth, motility, and glycolysis in vitro and in vivo. Mechanistically, leptin associated with EGFR, resulting in enhanced cell growth through the regulation of cell-cycle related markers, glycolysis-related genes, and EGFR/AKT/c-Myc signaling. Moreover, leptin potentiated the invasive capacity of NPC cells by promoting EMT. We further explored that miR-874-3p influenced leptin-mediated NPC progression. Overexpression of miR-874-3p prevented cell growth, motility, glucose consumption, and lactate production in NPC cells, whereas miR-874-3p inhibition had the opposite effects. AGO-RIP assays confirmed that Argonaute 2 (AGO2), a protein associated with miR-874-3p, regulated leptin expression in NPC cells. The rescue assays indicated that inhibition of leptin suppressed the effects of miR-874-3p inhibitor. In clinical specimens, miR-874-3p was negatively correlated with leptin.

Conclusions

Leptin may serve as a novel prognostic factor and potential therapeutic target for patients with NPC. In addition, a newly discovered regulatory axis of leptin/EGFR/AKT/c-Myc can provide a novel therapeutic strategy for NPC.

The role of altered microRNA expression in premalignant and malignant head and neck lesions with epithelial origin

Background and Aims

The premalignant lesions of the oral cavity carry a risk of transformation to malignancy. Hence, early diagnosis followed by timely intervention remarkably affects the prognosis of patients. During tumorigenesis, particular microRNAs (miRNAs) show altered expressions and because of their post transcriptionally regulatory role could provide favorable diagnostic, therapeutic, or prognostic values in head and neck cancers.

Methods

In this review, we have demonstrated diagnostic, prognostic, and potential therapeutic roles of some miRNAs associated with oral premalignant and malignant lesions based on previous validate studies.

Results

It is previously documented that dysregulation of miRNAs contributes to cancer development and progression. MiRNAs could be tumor suppressors that normally suppress cell proliferation, differentiation, and apoptosis or play as oncogenes that improved tumorigenesis process. Altered expression of miRNAs has also been reported in premalignant oral epithelial lesions such as leukoplakia, oral submucous fibrosis, oral lichen planus and some malignant carcinoma like oral squamous cell, verrucous, spindle cell, Merkel cell carcinoma and basal cell.

Conclusion

Some of miRNAs could be new therapeutic candidates in miRNA‐based target gene therapy. Although more investigations are required to identify the most favorable miRNA candidate, altered expression of some miRNAs could be used as biomarkers in premalignant lesions and oral cancers with high sensitivity and specificity.

Insulin receptor substrate-1 and dishevelled 2 are negatively regulated by microRNA-144 and inhibit nasopharyngeal carcinoma cell malignancy

Insulin receptor substrate-1 (IRS-1) is reported to play a critical role in the development, progression, invasion and metastasis of several types of tumors and is abnormally expressed in nasopharyngeal carcinoma (NPC). Although IRS-1 is predicted to be targeted by microRNA (miR)-144, the biological roles and potential mechanisms of miR-144 in NPC remain unclear. In the present study, the expression levels of miR-144 and IRS-1 in several NPC cell lines were first examined, and found that they were negatively correlated. Following the introduction of the miR-144 mimic, IRS-1 was downregulated at the protein level without affecting the mRNA level. The Cell Counting Kit-8 assay showed that the miR-144 mimic and siRNA targeting IRS-1 mRNA significantly decreased cell proliferation by arresting the cell cycle at the G₁/G₀ phase. The malignant behaviours of NPC cell lines, including migration, invasion and tumour formation in soft agar, were then analyzed after regulating miR-144 levels; as expected, the results showed that both the miR-144 mimic and siIRS-1 decreased these malignant behaviours. Furthermore, the downregulation of IRS-1 by miR-144 decreased the expression level of dishevelled 2 (Dvl2) protein without affecting its mRNA level, and Dvl2 overexpression abolished the inhibitory effect of the miR-144 mimic in NPC, indicating that miR-144 potentially regulates NPC by indirectly regulating Dvl2. Taken together, the present study results suggest that miR-144 acts as a tumour suppressor in NPC cell lines by regulating IRS-1 and Dvl2, which indicates that it is a potential therapeutic target for NPC treatment.

The potential of miRNA-based therapeutics in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection: A review

Since the World Health Organization (WHO) declared COVID-19, the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as a pandemic in March 2020, and more than 117 million people worldwide have been confirmed to have been infected. Scientists, medical professionals, and other stakeholders are racing against time to find and develop effective medicines for COVID-19. However, no drug with high efficacy to treat SARS-CoV-2 infection has been approved. With the increasing popularity of gene therapy, scientists have explored the utilization of small RNAs such as microRNAs (miRNAs) as therapeutics. miRNAs are non-coding RNAs with high affinity for the 3'-UTRs of targeted messenger RNAs (mRNAs). Interactions between host cells and viral genomes may induce the upregulation or downregulation of various miRNAs. Therefore, understanding the expression patterns of these miRNAs and their functions will provide insights into potential miRNA-based therapies. This review systematically summarizes the potential targets of miRNA-based therapies for SARS-CoV-2 infection and examines the viability of possible transfection methods.

A network meta-analysis for efficacies and toxicities of different therapeutic regimens in the treatment of advanced nasopharyngeal carcinoma

PURPOSE

The current study set out to compare the efficacies and toxicities (grad 3 and 4) between concurrent chemoradiotherapy (CCRT), induction chemotherapy plus radiotherapy (IC + RT), IC + CCRT, RT and CCRT + adjuvant chemotherapy (CCRT + AC) in regard to advanced nasopharyngeal carcinoma (NPC) treatment using a network meta-analysis.

METHODS

Literature retrieval was conducted using PubMed, Cochrane Library and other English databases. Eligible randomized controlled trails (RCTs) of 5 different regimens were included. The network meta-analysis combined direct and indirect comparisons to measure pooled odd ratios (OR) and the surface under the cumulative ranking curves (SUCRA).

RESULTS

A total of eight eligible RCTs were enrolled into this network meta-analysis after initial exclusion. With respect to hematologic toxicity, CCRT + AC exhibited higher toxicity in patients with advanced NPC in terms of anemia and leukopenia/neutropenia compared to RT. As for anemia, the toxicity of IC + CCRT was higher than those with advanced NPC. In addition, CCRT exhibited higher toxicity than RT in relation to leukopenia/neutropenia. Non-hematologic toxicity in regard to nausea/vomiting suggested that CCRT, IC + CCRT and CCRT + AC presented with higher levels of toxicity in patients with advanced NPC, in contrast to RT. Lastly, RT was found to be less toxic but with higher five-year overall survival (OS) rate in patients with advanced NPC, while CCRT, IC + CCRT and CCRT + AC were more toxic in patients with advanced NPC.

CONCLUSION

Among the five therapeutic regimens, the survival rate of IC + RT was similar to that of CCRT, and the toxicity SUCRA value of IC + RT was lower than that of CCRT. Together, our findings indicate that IC + RT may be a potentially acceptable treatment alternative to CCRT for advanced NPC, and is worthy of further investigation.

Diagnostic and Prognostic Indications of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a disease that is highly associated with the latent infection of Epstein–Barr virus. The absence of obvious clinical signs at the early stage of the disease has made early diagnosis practically impossible, thereby promoting the establishment and progression of the disease. To enhance the stride for a reliable and less invasive tool for the diagnosis and prognosis of NPC, we synopsize biomarkers belonging to the two most implicated biological domains (oncogenes and tumor suppressors) in NPC disease. Since no single biomarker is sufficient for diagnosis and prognosis, coupled with the fact that the known established methods such as methylation-specific polymerase chain reaction (PCR), multiplex methylation-specific PCR, microarray assays, etc., can only accommodate a few biomarkers, we propose a 10-biomarker panel (KIT, LMP1, PIKC3A, miR-141, and miR-18a/b (oncogenic) and p16, RASSF1A, DAP-kinase, miR-9, and miR-26a (tumor suppressors)) based on their diagnostic and prognostic values. This marker set could be explored in a multilevel or single unified assay for the diagnosis and prognosis of NPC. If carefully harnessed and standardized, it is hoped that the proposed marker set would help transform the diagnostic and prognostic realm of NPC, and ultimately, help prevent the life-threatening late-stage NPC disease.

MicroRNAs: Biogenesis, Functions and Potential Biomarkers for Early Screening, Prognosis and Therapeutic Molecular Monitoring of Nasopharyngeal Carcinoma

According to reports published, the aberrant expression of microRNAs (miRNAs), a class of 19–25 nucleotide-long small non-coding RNAs, is responsible for human cancers, including nasopharyngeal cancer (NPC). The dysregulation of miRNAs that act either as a tumor suppressor or oncogene, leading to a wide range of NPC pathogenesis pathways, includes the proliferation, invasion, migration as well as the metastasis of NPC cells. This article reviews and highlights recent advances in the studies of miRNAs in NPC, with a specific demonstration of the functions of miRNA, especially circulating miRNAs, in the pathway of NPC pathogenesis. Additionally, the possible use of miRNAs as early screening and prognostic biomarkers and for therapeutic molecular monitoring has been extensively studied.

MIR106A-5p upregulation suppresses autophagy and accelerates malignant phenotype in nasopharyngeal carcinoma

Dysregulated microRNAs (miRNAs) are involved in carcinoma progression, metastasis, and poor prognosis. We demonstrated that in nasopharyngeal carcinoma (NPC), transactivated MIR106A-5p promotes a malignant phenotype by functioning as a macroautophagy/autophagy suppressor by targeting BTG3 (BTG anti-proliferation factor 3) and activating autophagy-regulating MAPK signaling. MIR106A-5p expression was markedly increased in NPC cases based on quantitative real-time PCR, miRNA microarray, and TCGA database analysis findings. Moreover, MIR106A-5p was correlated with advanced stage, recurrence, and poor clinical outcomes in NPC patients. In addition to three-dimensional cell culture assays, zebrafish and BALB/c mouse tumor models revealed that overexpressed MIR106A-5p targeted BTG3 and accelerated the NPC malignant phenotype by inhibiting autophagy. BTG3 promoted autophagy, and its expression was correlated with poor prognosis in NPC. Attenuation of autophagy, mediated by the MIR106A-5p-BTG3 axis, occurred because of MAPK pathway activation. MIR106A-5p overexpression in NPC was due to increased transactivation by EGR1 and SOX9. Our findings may lead to novel insights into the pathogenesis of NPC.

Abbreviations: ACTB: actin beta; ATG: autophagy-related; ATG5: autophagy related 5; BLI: bioluminescence; BTG3: BTG anti-proliferation factor 3; CASP3: caspase 3; ChIP: chromatin immunoprecipitation; CQ: chloroquine; Ct: threshold cycle; DAPI: 4ʹ,6-diamidino-2-phenylindole; DiL: 1,1ʹ-dioctadecyl-3,3,3ʹ,3ʹ-tetramethylindocarbocyanine perchlorate; EBSS: Earle’s balanced salt solution; EGR1: early growth response 1; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GEO: Gene Expression Omnibus; GFP: green fluorescent protein; IF: immunofluorescence; IHC: immunohistochemistry; ISH: in situ hybridization; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MIR106A-5p: microRNA 106a-5p; miRNAs: microRNAs; MKI67: marker of proliferation ki-67; mRNA: messenger RNA; MTOR: mechanistic target of rapamycin kinase; NPC: nasopharyngeal carcinoma; qRT-PCR: quantitative real-time PCR; siRNA: small interfering RNA; SOX9: SRY-box transcription factor 9; SQSTM1: sequestosome 1; TCGA: The Cancer Genome Atlas; WB: western blot.

The potential of circulating exosomal RNA biomarkers in cancer

INTRODUCTION

There are great potentials of using exosomal RNAs (exoRNA) as biomarkers in cancers. The isolation of exoRNA requires the use of ultracentrifugation to isolate cell-free RNA followed by detection using real-time PCR, microarray, next-generation sequencing, or Nanostring nCounter system. The use of exoRNA enrichment panels has largely increased the detection sensitivity and specificity when compared to traditional diagnostic tests. Moreover, using exoRNA as biomarkers can assist the early detection of chemo and radioresistance cancer, and in turn opens up the possibility of personalized treatment to patients. Finally, exoRNA can be detected at an early stage of cancer recurrence to improve the survival rate.

AREAS COVERED

In this review, the authors summarized the detection methods of exoRNA as well as its potential as a biomarker in cancer diagnosis and chemo and radioresistance.

EXPERT OPINION

The application of exoRNAs in clinical diagnosis is still in its infancy. Further researches on extracellular vesicles isolation, detection protocols, exoRNA classes and subclasses, and the regulatory biological pathways have to be performed before exoRNA can be applied translationally.

LncRNA DLX6-AS1 increases the expression of HIF-1α and promotes the malignant phenotypes of nasopharyngeal carcinoma cells via targeting MiR-199a-5p

OBJECTIVE

To investigate the expression of long-chain noncoding growth stasis specific protein 6 antisense RNA1 (lncRNA DLX6-AS1) in nasopharyngeal carcinoma (NPC) tissues and cells, and its regulatory effect on malignant phenotypes of NPC cells.

METHODS

The expressions of DLX6-AS1, miR-199a-5p, and HIF-1α mRNA in NPC issues and cells were detected by qRT-PCR. The proliferation, metastasis, and invasion of cells were monitored via MTT and transwell assay. The interactions between DLX6-AS1 and miR-199a-5p, miR-199a-5p and HIF-1α were verified by luciferase activity assay. Western blot was performed to determine the regulatory effect of DLX6-AS1 and miR-199a-5p on HIF-1α protein.

RESULTS

The expression of lncRNA DLX6-AS1 was up-regulated in NPC tissues and cells. The proliferation, migration, and invasion of NPC were enhanced by overexpressed DLX6-AS1 but inhibited by DLX6-AS1 knockdown. In addition, DLX6-AS1 can be used as a kind of ceRNA to regulate miR-199a-5p and, thereby modulating the expression of HIF-1α.

CONCLUSION

We found that DLX6-AS1 was a cancer-promoting lncRNA to facilitate the progression of NPC, and its underlying mechanism was suppressing miR-199a-5p expression. This study can provide novel clues for the treatment of NPC.

Association Between LMP-1, LMP-2, and miR-155 Expression as Potential Biomarker in Nasopharyngeal Carcinoma Patients: A Case/Control Study in Vietnam

Background: Epstein-Barr virus (EBV) infection and microRNA-155 (miR-155) are considered etiological factors that contribute to nasopharyngeal carcinoma (NPC). The regulation of miR-155 expression induced by EBV infection has been reported to be important in NPC tumorigenesis. Aims: This study was designed to explore the relationships among the expression levels of miR-155, LMP-1 (latent membrane protein-1), and LMP-2 (latent membrane protein-2) in tumor and nontumor specimens of Vietnamese NPC patients. The study was also designed to investigate the association between miR-155 expression and LMP-1 and LMP-2 expression in Vietnamese NPC patients. Materials and Methods: Ninety-three NPC biopsy samples and 100 noncancerous swab specimens were collected from patients and analyzed by real-time reverse transcriptase polymerase chain reaction. Results: LMP-1, LMP2, and miR-155 were significantly upregulated in 76.34%, 67.74%, and 75.27% of NPC samples, respectively, with decreased expression observed in the control group (p < 0.0001). Moreover, the statistical analysis showed that there was a close association between LMP-1 and LMP-2 expression and miR-155 expression in the NPC samples. Conclusion: miR-155 expression was upregulated and significantly associated with the expression of LMP-1 and LMP-2, in Vietnamese NPC cases.

LINC00958 Promotes The Malignancy Of Nasopharyngeal Carcinoma By Sponging microRNA-625 And Thus Upregulating NUAK1

Purpose

The aberrant expression of long noncoding RNAs (lncRNAs) indicates progression of various diseases. LINC00958 has been well studied in several types of human cancer; however, the expression profile, functions, and potential mechanism of action of this lncRNA in nasopharyngeal carcinoma (NPC) remain largely unclear and still need to be elucidated. In the present study, we aimed to measure LINC00958 expression in NPC, determine its clinical value, and explore its roles in NPC progression as well as the mechanisms behind these processes.

Methods

The expression profile of LINC00958 in NPC was evaluated by reverse-transcription quantitative polymerase chain reaction (RT-qPCR). A series of functional assays, including the Cell Counting Kit-8 assay, flow cytometry, a Transwell assay, and an in vivo nude mouse model, were utilized to determine the participation of LINC00958 in the malignancy of NPC.

Results

LINC00958 was found to be upregulated in NPC tissue specimens and cell lines. The LINC00958 overexpression significantly correlated with tumor size, lymph node status, TNM stage, and worse overall survival among NPC patients. Downregulation of LINC00958 suppressed NPC cell proliferation, migration, and invasion and induced apoptosis in vitro. Additionally, the LINC00958 knockdown impaired tumor growth in vivo. Mechanistically, LINC00958 was found to serve as a molecular sponge of microRNA-625 (miR-625), thereby upregulating NUAK family SNF1-like kinase 1 (NUAK1) in NPC cells. Lastly, rescue experiments validated the involvement of the miR-625–NUAK1 axis in LINC00958-mediated biological functions in NPC.

Conclusion

Our results demonstrated that LINC00958 works as an oncogene in NPC and plays a key role in the malignant phenotype of NPC cells by sponging miR-625 and increasing NUAK1 expression. The LINC00958–miR-625–NUAK1 pathway might be a target for anticancer therapy in patients with NPC.

The four‑microRNA signature identified by bioinformatics analysis predicts the prognosis of nasopharyngeal carcinoma patients

The aim of the present study was to identify microRNAs (miRNAs) that predict the prognosis of patients with nasopharyngeal carcinoma by integrated bioinformatics analysis. First, the original microarray dataset GSE32960, including 312 nasopharyngeal carcinomas and 18 normal samples, was downloaded from the Gene Expression Omnibus database. In addition, 46 differentially expressed miRNAs (DEMs) were screened. Then, four miRNAs, including hsa-miR-142-3p, hsa-miR-150, hsa-miR-29b, and hsa-miR-29c, were obtained as prognostic markers by combining univariate Cox regression analysis with weighted gene coexpression network analysis (WGCNA). Subsequently, the risk score of 312 NPC patients from the signature of miRNAs was calculated, and patients were divided into high-risk or low-risk groups. Notably, compared with patients with low-risk scores, high-risk groups had shorter disease-free survival (DFS), overall survival (OS), and distant metastasis-free survival (DMFS). Receiver operating characteristic curve (ROC) analysis indicated that the risk score was a very effective prognostic factor. Moreover, the Search Tool for the Database for Annotation, Visualization, and Integrated Discovery (DAVID), Cytoscape, starBase, and Retrieval of Interacting Genes database (STRING) were used to establish the miRNA-mRNA correlation network and the protein-protein interaction (PPI) network. In addition, the shared genes superimposing 888 protein-coding genes targeted by four hub miRNAs and 1,601 upregulated differentially expressed mRNAs accounted for 127 and were used for subsequent gene functional enrichment analysis. In particular, biological pathway analysis indicated that these genes mainly participate in some vital pathways related to cancer pathogenesis, such as the focal adhesion, PI3K/Akt, p53, and mTOR signalling pathways. In summary, the identification of NPC patients with a four-miRNA signature may increase the prognostic value and provide reference information for precision medicine.

Multi-parameters of Magnetic Resonance Imaging to Estimate Ischemia-Reperfusion Injury after Stroke in Hyperglycemic Rats

The aim of the study is to verify the effect of hyperglycemia on ischemia-reperfusion injury and to explore the feasibility of noninvasive observation of ischemic-reperfusion injury in hyperglycemic ischemic stroke by MRI technique. According to the duration of ischemia and blood glucose levels, 40 rats were divided into hyperglycemic ischemic 2-hr (H-I2h), hyperglycemic ischemic 6-hr (H-I6h), non- hyperglycemic ischemic 2-hr (NH-I2h), and non- hyperglycemic ischemic 6-hr (NH-I6h) groups. T2W imaging, DW imaging, T2 mapping, T2* mapping, DCE, and T1 mapping after enhancement sequences were acquired before reperfusion and approximately 3-hr after reperfusion. ADC, T1, T2, T2*, and Ktrans values of ischemic lesion were obtained in different groups. After reperfusion, the variation of ADC values showed no significant difference between groups with diabetes and groups without diabetes and between different recanalization time-points (2-hr vs 6-hr). After reperfusion, T2, T2*, and Ktrans values increased in different degrees in all four groups. Only the T1 value decreased in all groups. The change of all parameters in groups with hyperglycemia was more obvious than that in groups without hyperglycemia and was more obvious in groups with H-I6h versus those with H-I2h. This study confirms that hyperglycemia aggravates ischemia-reperfusion injury and may be an important risk factor for the prognosis of ischemic stroke. The Ktrans values should be noninvasive imaging indicators to monitor blood brain barrier permeability and ischemic-reperfusion injury in ischemic stroke.

Systematic review and meta-analysis of prognostic microRNA biomarkers for survival outcome in nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal cancer (NPC), despite being one of the most malignant head and neck carcinomas (HNC), lacks comprehensive prognostic biomarkers that predict patient survival. Therefore, this systematic review and meta-analysis is aimed to evaluate the potential prognostic value of miRNAs as prognostic biomarkers in NPC.

METHODS

PRISMA guidelines were used to conduct this systematic review and meta-analysis study. Permutations of multiple "search key-words" were used for the search strategy, which was limited to articles published between January 2012 and March 2018. The retrieved articles were meticulously searched with multi-level screening by two reviewers and confirmed by other reviewers. Meta-analysis was performed using Hazard Ratios (HR) and associated 95% Confidence Interval (CI) of survival obtained from previously published studies. Publication bias was assessed by Egger's bias indicator test and funnel plot symmetry.

RESULTS

A total of 5069 patients across 21 studies were considered eligible for inclusion in the systematic review, with 65 miRNAs being evaluated in the subsequent meta-analysis. Most articles included in this study originated from China and one study from North Africa. The forest plot was generated using cumulated survival data, resulting in a pooled HR value of 1.196 (95% CI: 0.893-1.601) indicating that the upregulated miRNAs increased the likelihood of death of NPC patients by 19%.

CONCLUSION

To our knowledge, this is the first meta-analysis that examines the prognostic effectiveness of miRNAs as biomarkers in NPC patients. We noted that the combined effect estimate of HR across multiple studies indicated that increased miRNA expression in NPC potentially leads to poor overall survival. However, further large-scale prospective studies on the clinical significance of the miRNAs, with sizable cohorts are necessary in order to obtain conclusive results.

PI3K-PKB-mTOR hyperactivation in relation to nasopharyngeal carcinoma progression and prognosis

Nasopharyngeal carcinoma (NPC) has a unique and complex etiology, which is not completely understood. The aim of this study is to investigate the expression patterns of phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB), and mammalian target of rapamycin (mTOR) proteins in patients with NPC and their relationship with NPC progression and prognosis. Between January 2008 and March 2010, PI3K, PKB, and mTOR protein expressions were detected using immunohistochemistry among 119 patients with NPC and 30 healthy people. A 5-year follow-up was conducted for all patients. Correlations of PI3K, PKB, and mTOR proteins with the clinicopathological features and prognosis of NPC were evaluated using Spearman's rank correlation coefficient and Kaplan-Meier curve. Cox's regression analysis was performed to analyze the risk factors for the prognosis of NPC. First, PI3K, PKB, and mTOR were highly expressed in patients with NPC. The expressions of PI3K, PKB, and mTOR proteins were associated with T stage, N stage, clinical stage, relapse, and distant metastasis. Meanwhile, PI3K is positively correlated with PKB and PKB is positively correlated with mTOR in NPC. Higher PI3K, PKB, and mTOR protein expressions were related to a shorter survival time and a lower survival rate in NPC. Cox regression analysis revealed that age, T stage, N stage, PI3K, PKB, and mTOR were independent risk factors for NPC patient survival. Altogether, our data suggest that overexpression of PI3K, PKB, and mTOR proteins is an important indicator of poor survival in NPC. In addition, inhibition of PI3K-PKB-mTOR signaling may also contribute to the development of new therapeutic strategies for NPC.

MicroRNA-663b promotes cell proliferation and epithelial mesenchymal transition by directly targeting SMAD7 in nasopharyngeal carcinoma

MicroRNAs (miRs) serve important roles in the development of various types of human cancer, including nasopharyngeal carcinoma (NPC). In the present study, the expression levels of miR-663b in NPC were investigated and its role and underlying mechanisms were examined. Reverse transcription-quantitative polymerase chain reaction was performed to assess miR-663b expression levels in NPC tissues and C666-1 cells. TargetScan was applied to predict the putative targets of miR-663b and the dual luciferase reporter assay was used to confirm the predictions. To investigate the role of miR-663b in NPC, the NPC C666-1 cell line was transfected with miR-663b mimics, miR-663b inhibitors or negative control. The Cell Counting kit-8 assay was performed for cell proliferation detection and western blot analysis was applied to determine the expression levels of epithelial mesenchymal transition (EMT)-associated proteins. Results indicated that when compared with the adjacent normal tissues and the normal nasopharyngeal epithelial cells, miR-663b expression levels were significantly upregulated in the NPC tissues and the NPC cells (P<0.01). Notably, SMAD7 is a target gene of miR-663b and may be inhibited by miR-663b. Results indicated that NPC cell proliferation was significantly promoted by miR-663b mimics and significantly inhibited by miR-663b inhibitors (P<0.05 and P<0.01). In addition, the results indicated that, when compared with the negative control group the expression levels of E-cadherin were significantly decreased, whereas the expression levels of N-cadherin, Vimentin and matrix metalloproteinase-9 were significantly increased in the cells of the miR-663b mimics group (P<0.05 and P<0.01). However, cells in the miR-663b inhibitors group exhibited the opposite effects. In conclusion, the results of the present study indicated that miR-663b functions as a tumor promoter in NPC via promoting NPC cell proliferation and EMT by directly targeting SMAD7.

Exosomes in Nasopharyngeal Carcinoma

Exosomes are nanosized (30-100nm) membrane microvesicles secreted through a complex cellular process. Exosomes contain a variety of bioactive molecules, such as proteins, microRNAs(miRNAs or miRs) and long non-coding RNAs (lncRNAs), playing an important role in the cell-to-cell substance transportation and signal transduction. Nasopharyngeal carcinoma-related exosomes (NPC-Exo) have been identified in circulating blood and contribute to tumor cell proliferation, angiopoiesis, and immune tolerance through remodeling of tumor microenvironment (TME). Nasopharyngeal carcinoma-related exosomes may also induce epithelial-mesenchymal transition (EMT), thus promoting tumor metastasis and chemoradioresistance. Clinically, the exosomes may serve as novel biomarkers for diagnosis and targeted therapies of nasopharyngeal carcinoma. This review article updates the understanding of exosomes in nasopharyngeal carcinoma(NPC).

The expression of microRNA-324-3p as a tumor suppressor in nasopharyngeal carcinoma and its clinical significance

Objective

This study aimed to determine the expression, clinical significance, and possible biologic function of microRNA-324-3p in nasopharyngeal carcinoma (NPC) tissues.

Methods

In total, 54 NPC and 35 control tissues were collected. The correlation between miR-324-3p expression and the clinicopathologic characteristics was analyzed. A dual-luciferase reporter gene assay was employed to examine the predicted target gene of miR-324-3p. The miR-324-3p expression level in 5–8F cells was determined with quantitative reverse transcription-polymerase chain reaction following the transfection of miR-324-3p mimics and inhibitors. Cell proliferation and the percentage of apoptosis were measured with MTT and flow cytometry. Cell invasion ability was assessed by Transwell invasion assay.

Results

Our results showed that miR-324-3p was downregulated in the NPC tissues. The expression level of miR-324-3p in poorly differentiated NPC was significantly reduced in comparison with that in well/moderately differentiated NPC. The expression level in clinical stages III/IV was lower than that in clinical stages I/II. Moreover, the expression level of miR-324-3p was significantly lower in NPC patients with lymph node metastasis than that in NPC patients without lymph node metastasis. NPC patients with higher levels of miR-324-3p expression also demonstrated a longer survival time. Predictions from bioinformatics indicated the Hedgehog pathway transcription gene GLI3 as the target gene of miR-324-3p, and the dual- luciferase reporter assay showed that miR-324-3p is directly combined with the 3′-untranslated region of GLI3. The overexpression of miR-324-3p suppressed cell proliferation and invasion, and it enhanced apoptosis in 5–8F cells.

Conclusion

miR-324-3p can act as a tumor suppressor in NPC cells by the negative regula- tion of GLI3 gene.

The long noncoding RNA FOXCUT promotes proliferation and migration by targeting FOXC1 in nasopharyngeal carcinoma

Long noncoding RNAs play an important role in various biological processes, including tumorigenesis. FOXC1 (Forkhead box C1) is a member of the Forkhead box family of transcription factors and plays a crucial role in nasopharyngeal carcinoma. In this study, a novel long noncoding RNA (FOXCUT) located upstream of FOXC1 was investigated in 42 nasopharyngeal carcinoma patients. Our analysis revealed that the expression levels of FOXCUT and FOXC1 in nasopharyngeal carcinoma tissues were significantly higher than those observed in chronic nasopharyngitis tissues and that FOXCUT expression was positively correlated with FOXC1 expression. Additionally, knockdown of FOXCUT significantly inhibited proliferation and migration of nasopharyngeal carcinoma cell lines and resulted in downregulated expression of the matrix metalloproteinase 7 and matrix metalloproteinase 9, as well as vascular endothelial growth factor A and β-catenin. Our findings suggested that FOXCUT expression contributed to the development and progression of nasopharyngeal carcinoma by targeting FOXC1 and that FOXCUT might be useful as a potential nasopharyngeal carcinoma biomarker and therapeutic target.

MicroRNA-148b suppresses proliferation, migration, and invasion of nasopharyngeal carcinoma cells by targeting metastasis-associated gene 2

PURPOSE

MicroRNAs (miRNAs) play important roles in tumorigenesis and metastasis by regulating genes expression. MiRNA-148b (miR-148b) had been reported to inhibit tumor progression in some kinds of cancers, but the functions of miR-148b in nasopharyngeal carcinoma (NPC) remain largely unknown. The aim of this study was to investigate the functional role of miR-148b in NPC.

METHODS

Expression of miR-148b in NPC tissues and cell lines was detected by quantitative reverse transcription polymerase chain reaction. MiR-148b was overexpressed in CNE2 and C666-1 cells by miR-148b mimic transfection. The effects of miR-148b on cell proliferation, migration, and invasion were determined by colony formation assays, cell viability assays, and transwell assays. The target gene of miR-148b was investigated by luciferase assays, and the rescue experiment was performed.

RESULTS

MiR-148b was downregulated in NPC tissues and cell lines. Ectopic miR-148b expression significantly inhibited proliferation, migration, and invasion of CNE2 and C666-1 cells. We identified that metastasis-associated gene 2 (MTA2) is a direct target of miR-148b. Rescue experiment demonstrated that the tumor-suppressive effects of miR-148b on C666-1 cell were partly reversed by restoration of MTA2 expression. Moreover, miR-148b expression was negatively related to mRNA level of MTA2 in NPC tissues.

CONCLUSION

Our findings elucidate that miR-148b negatively regulates the growth, migration, and invasion of NPC cells, at least in part, by targeting MTA2. The present study indicates that miR-148b is a potential therapeutic agent for NPC.

miR-185-3p regulates the invasion and metastasis of nasopharyngeal carcinoma by targeting WNT2B in vitro

MicroRNAs (miRs) have been recognised as important regulators of malignant behaviour in different types of human cancer, including nasopharyngeal carcinoma (NPC). A previous study by our group revealed that miR-185-3p regulates the radioresistance of NPC cells. The present study aimed to investigate the effect of miR-185-3p on NPC invasion and metastasis. Human NPC CNE-2 and 5-8F cell lines were transfected with a miR-185-3p mimic and miR-185-3p inhibitor, respectively, and their effects on the invasion and metastasis of these cells was assessed using a wound healing assay and Matrigel invasion assay. The target gene of miR-185-3p, Wnt family member 2B (WNT2B) was silenced in 5-8F cells using siRNA in order to investigate its function in NPC. Data from the present study demonstrated that the expression of miR-185-3p was the highest in 5-8F and lowest in CNE-2 cells out of a range of NPC cell lines. Following the transfection of miR-185-3p mimic into CNE-2 cells, the wound healing and Matrigel invasion assays indicated that the migration and invasion ability of CNE-2 cells was significantly reduced compared with the negative control group. In addition, the inhibition of miR-185-3p in 5-8F cells significantly increased the capacity for migration and invasion. Furthermore, silencing WNT2B expression resulted in a significant reduction in the invasion and metastasis in 5-8F cells. The inhibition of miR-185-3p, which promotes invasion and metastasis, could be reversed through the silencing of WNT2B in 5-8F cells. The results of the present study indicate that miR-185-3p mediates the invasion and metastasis of NPC by targeting WNT2B in vitro.

MicroRNA‑152 inhibits cell proliferation, migration and invasion by directly targeting MAFB in nasopharyngeal carcinoma

Aberrant expression of microRNAs (miRs) has been reported to be involved in nasopharyngeal carcinoma (NPC) carcinogenesis and development. The expression and functions of miR‑152 have previously been studied in several types of cancer. However, to the best of our knowledge, no previous studies have investigated the effects of miR‑152 on NPC. The present study aimed to explore the expression, functions and molecular mechanisms of miR‑152 in NPC. The expression levels of miR‑152 were detected in NPC tissues and cell lines using quantitative polymerase chain reaction (qPCR). Cell proliferation, migration and invasion were measured by MTT, cell migration and invasion assays, respectively. Dual‑luciferase reporter assay was used to determine whether V‑maf avian musculoaponeurotic fibrosarcoma oncogene homolog B (MAFB) was a direct target gene of miR‑152. qPCR and western blotting were used to detect the mRNA and protein expression levels of MAFB. In addition, functional assays were performed to explore the effects of endogenous MAFB on NPC. The results of the present study demonstrated that miR‑152 was significantly downregulated in NPC tissues and cell lines. Furthermore, ectopic expression of miR‑152 suppressed cell proliferation, migration and invasion of NPC cells. Dual‑luciferase reporter assay demonstrated that MAFB was a direct target gene of miR‑152, and qPCR and western blotting indicated that miR‑152 negatively regulated MAFB expression at the mRNA and protein level. Knockdown of MAFB expression markedly suppressed NPC cell proliferation, migration and invasion. These findings suggested that miR‑152 may target MAFB to regulate NPC initiation and progression; therefore, it may be investigated as a target for the treatment of NPC.

Hypoxia-induced hsa-miR-101 promotes glycolysis by targeting TIGAR mRNA in clear cell renal cell carcinoma

Increasing evidence suggests that microRNAs (miRNAs) are essential in carcinogenesis, therefore, the present study investigated the role of hsa‑miR‑101 in renal tumorigenesis and cancer development. On identification of its expression pattern, it may serve as a diagnostic biomarker for clear cell renal cell carcinoma (ccRCC). In the present study, 10 pairs of ccRCC and noncancerous tissue samples were obtained to examine whether the expression of hsa‑miR‑101 is linked to cancer. The data obtained were validated using reverse transcription‑quantitative polymerase chain reaction analysis. The levels of hsa‑miR‑101 were examined following exposure to hypoxia in ACHN and HK‑2 cells. As a predicted target, the mRNA and protein levels of TP53‑induced glycolysis and apoptosis regulator (TIGAR) were then assessed. A pcDNA‑GFP‑miR‑101 plasmid was stably transfected into ACHN and HK‑2 cells, following which the effects of hsa‑miR‑101 on the expression of TIGAR and inhibition of glycolysis were investigated. The present study also examined the association between the level of hsa‑miR‑101 and kidney tumors. It was identified that the expression level was significantly higher in the ccRCC tissues, compared with that in the corresponding noncancerous tissues. The expression values for the upregulated miRNA ranged between 4.6‑ and 67.9‑fold. On demonstrating the functional link between hypoxia and the expression of miRNAs changes in the expression of hsa‑miR‑101 were examined following hypoxia exposure in kidney tumor and non‑tumor cell lines. It was shown that hypoxia exposure significantly induced hsa‑miR‑101. The hypoxia‑induced upregulation of hsa‑miR‑101 repressed the activity of TIGAR by targeting TIGAR mRNA and promoting glycolysis. The results showed that the upregulation of hsa‑miR‑101 in ccRCC was induced by hypoxia. Its expression deceased the protein expression of TIGAR and promoted glycolysis. This regulatory pathway may represent a novel mechanism of carcinogenesis and requires further investigation.

The potent tumor suppressor miR-497 inhibits cancer phenotypes in nasopharyngeal carcinoma by targeting ANLN and HSPA4L

Nasopharyngeal carcinoma (NPC) is a malignancy with poor prognosis that is endemic to Southeast Asia. We profiled microRNAs (miRNAs) of NPCs using microarrays and confirmed the results by quantitative RT-PCR. The results revealed that seven miRNAs were significantly up-regulated, and six miRNAs were down-regulated, in NPC tissues relative to noncancerous nasopharyngeal epithelia (NNE). Expression of miR-497 was also significantly reduced in the plasma of NPC patients relative to the plasma of noncancerous control patients. The concordant down-regulation of miR-497 in tissues and plasma suggested that miR-497 could be used as a diagnostic biomarker for NPC. Functional analyses of the effect of miR-497 on cancer phenotypes revealed that transfection of miR-497 mimic into NPC cells suppressed cell growth and migration and induced apoptosis. Subcutaneous xenografts of transfected cells in nude mice demonstrated that miR-497 significantly inhibited tumor growth. Two potential targets of miR-497, ANLN (anillin, actin-binding protein) and HSPA4L (heat shock 70 kDa protein 4–like), both of which were overexpressed in NPC tissues, were negatively regulated by miR-497 mimic in NPC cell lines. Silencing of ANLN and HSPA4L suppressed cell proliferation and migration and induced apoptosis in NPC cells. Our findings indicate that miR-497 is a potent tumor suppressor that inhibits cancer phenotypes by targeting ANLN and HSPA4L in NPC.

Increased Serum Level of MicroRNA-663 Is Correlated with Poor Prognosis of Patients with Nasopharyngeal Carcinoma

MicroRNAs (miRs) play crucial roles in the carcinogenesis and malignant progression of human cancers including nasopharyngeal carcinoma (NPC). In this study, we aimed to investigate the association of serum miR-663 levels with the clinical factors and prognosis of NPC patients. Real-time PCR was performed to examine the amount of miR-663 in serum in NPC patients and healthy controls. Our data showed that the amount of miR-663 in serum was significantly higher in NPC patients than in healthy controls. Moreover, the serum levels of miR-663 were significantly correlated with the grade, lymph node metastasis, and clinical stage of NPC. Furthermore, higher serum miR-663 levels were closely associated with worse 5-year overall survival (OS) and relapse-free survival (RFS) of patients with NPC, and the serum level of miR-663 was found to be an independent predicator for the prognosis of NPC. In addition, after receiving chemoradiotherapy, the serum levels of miR-663 were significantly reduced in NPC patients. In summary, miR-663 was upregulated in the serum of NPC patients, which was downregulated after chemoradiotherapy, and its increased levels were closely associated with malignant progression and poor prognosis in NPC patients. Therefore, the amount of miR-663 in serum may become a potential predicator for the clinical outcome of NPC patients.