MicroRNA Deregulations in Head and Neck Squamous Cell Carcinomas

MicroRNA-98: the multifaceted regulator in human cancer progression and therapy

MicroRNA-98 (miR-98) stands as an important molecule in the intricate landscape of oncology. As a subset of microRNAs, these small non-coding RNAs have accompanied a new era in cancer research, underpinning their significant roles in tumorigenesis, metastasis, and therapeutic interventions. This review provides a comprehensive insight into the biogenesis, molecular properties, and physiological undertakings of miR-98, highlighting its double-edged role in cancer progression-acting both as a tumor promoter and suppressor. Intriguingly, miR-98 has profound implications for various aspects of cancer progression, modulating key cellular functions, including proliferation, apoptosis, and the cell cycle. Given its expression patterns, the potential of miR-98 as a diagnostic and prognostic biomarker, especially in liquid biopsies and tumor tissues, is explored, emphasizing the hurdles in translating these findings clinically. The review concludes by evaluating therapeutic avenues to modulate miR-98 expression, addressing the challenges in therapy resistance, and assessing the efficacy of miR-98 interventions. In conclusion, while miR-98's involvement in cancer showcases promising diagnostic and therapeutic avenues, future research should pivot towards understanding its role in tumor-stroma interactions, immune modulation, and metabolic regulation, thereby unlocking novel strategies for cancer management.

Salivary miRNAs as auxiliary liquid biopsy biomarkers for diagnosis in patients with oropharyngeal squamous cell carcinoma: a systematic review and meta-analysis

Objective: The healthcare system needs a novel approach to improve and diagnose early oropharyngeal squamous cell carcinoma against its low survival rate. We conduct a systematic review and a comprehensive meta-analysis for the diagnostic role of blood and salivary microRNAs (miRNAs). Methods: An unbiased and thorough literature search in PubMed yielded appropriate data from qualified articles regarding different miRNA biomarkers, method of extraction, research location, and year of publication. Stata was used to calculate the sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristic curve. Results: We included 9 studies with 399 qualified oropharyngeal squamous cell carcinoma patients, which yielded a high diagnostic accuracy of blood miRNAs in combination with salivary miRNAs with a sensitivity of 0.70 (p < 0.001), specificity of 0.75 (p = 0.26), diagnostic odds ratio of 7, and an area under the curve of 0.78. Conclusion: Combined blood- and saliva-derived miRNAs demonstrated a high diagnostic accuracy in detecting oropharyngeal squamous cell carcinoma. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024509424.

Tumor hypoxia and role of hypoxia-inducible factor in oral cancer

BACKGROUND

Head and neck cancer (HNC) is one of the most frequent malignancies in Asian males with a poor prognosis. Apart from well-known prognostic indicators, markers of tumor hypoxia can help us predict response to treatment and survival.

METHODS

A review of the literature on the present evidence and potential clinical importance of tumor hypoxia in head and neck cancer was carried out. The data obtained from the literature search is presented as a narrative review.

RESULTS

The literature shows possible associations between prognosis and low tumor oxygenation. Intermediate hypoxia biomarkers like HIF-1, GLUT-1, miRNA, and lactate, can help in predicting the response to therapy and survival as their altered expression is related to prognosis.

CONCLUSIONS

Hypoxia is common in HNC and can be detected by use of biomarkers. The tumors that show expression of hypoxia biomarkers have poor prognosis except for patients with human papilloma virus-associated or VHL-associated cancers. Therapeutic targeting of hypoxia is emerging; however, it is still in its nascent stage, with increasing clinical trials hypoxia is set to emerge as an attractive therapeutic target in HNC.

Diagnostic and Prognostic Value of miR-93 in Prostate Cancer: A Meta-Analysis and Bioinformatics Analysis

Background

Accurate and non-invasive diagnostic and prognostic markers are necessary to improve patient outcomes. MicroRNAs have been proposed as relatively non-invasive and pertinent biomarkers. miR-93 has been studied for its potential as a diagnostic and prognostic marker in prostate cancer (PCa), but findings from individual studies are inconsistent. We conducted a meta-analysis of its overall differential expression in 13 PCa studies and a bioinformatics analysis to provide a comprehensive appraisal of its diagnostic and prognostic role.

Methods

We searched all published papers on miR-93 expression in PCa up to Nov 30, 2022 using PubMed, Science Direct, Web of Science, Cochrane Central Register of Controlled Trials databases. We used RevMan software to Meta-analyze the included literature. A bioinformatics analysis of genes and pathways that might be target to the effect of the mature miR-93-5p was carried out.

Results

The pooled standardized mean difference (SMD) of miR-93 expression in PCa, its area under the curve (AUC) and hazard ratio (HR) were 1.26, 95% CI [-0.34-2.86], 0.84, 95% CI [0.76 -0.93] and 1.67, 95% CI [0.98, 2.84] respectively. Bioinformatics analysis revealed that mature miR-93-5p may regulate genes such as SMAD1, SMAD7 and MAPK and the PI3K-Akt signaling pathways.

Conclusion

miR-93 has significant diagnostic and prognostic value in PCa. These findings highlight the potential of miR-93 as a non-invasive biomarker for PCa and may contribute to earlier detection and prognostic assessment. The target genes and signaling pathways regulated by miR-93 may provide insights into the underlying molecular mechanisms of PCa.

Insight on common forms of cutaneous head and neck carcinoma (Review)

To improve the outcome and quality of life for patients with head and neck carcinoma, an increasing amount of research has been performed on the particularities of this type of cancer and its treatment methods. Starting from clinical aspects, including histology and imaging features, up-to-date studies from different parts of the world have determined new data leading to a better understanding of the mechanisms behind the disease and proposed new treatment protocols. The head and neck areas are predisposed to almost all skin neoplasms, most commonly those related to ultraviolet exposure. Squamous cell carcinoma and basal cell carcinoma account for almost 90% of non-melanoma skin cancers in this region; therefore, reviewing the literature on cutaneous carcinomas of the head and neck area and sharing particular aspects of their physiopathology are beneficial for a great number of patients.

Interplay between ceRNA and Epigenetic Control of microRNA: Modelling Approaches with Application to the Role of Estrogen in Ovarian Cancer

MicroRNAs (miRNAs) play an important role in gene regulation by degradation or translational inhibition of the targeted mRNAs. It has been experimentally shown that the way miRNAs interact with their targets can be used to explain the indirect interactions among their targets, i.e., competing endogenous RNA (ceRNA). However, whether the protein translated from the targeted mRNAs can play any role in this ceRNA network has not been explored. Here we propose a deterministic model to demonstrate that in a network of one miRNA interacting with multiple-targeted mRNAs, the competition between miRNA-targeted mRNAs is not sufficient for the significant change of those targeted mRNA levels, while dramatic changes of these miRNA-targeted mRNAs require transcriptional inhibition of miRNA by its target proteins. When applied to estrogen receptor signaling pathways, the miR-193a targets E2F6 (a target of estrogen receptor), c-KIT (a marker for cancer stemness), and PBX1 (a transcriptional activator for immunosuppressive cytokine, IL-10) in ovarian cancer, such that epigenetic silencing of miR-193a by E2F6 protein is required for the significant change of c-KIT and PBX1 mRNA level for cancer stemness and immunoevasion, respectively, in ovarian cancer carcinogenesis.

Prognostic impact of miR-34b/c DNA methylation, gene expression, and promoter polymorphism in HPV-negative oral squamous cell carcinomas

Micro RNAs (miRNAs) have a key role in gene expression regulation in cancer. The aim of the current study is to evaluate the prognostic value of miR-34b/c promoter hypermethylation, gene expression, and polymorphism in HPV-negative oral squamous cell carcinomas (OSCC). MiR-34b/c promoter hypermethylation and pre-miR-34b/c polymorphism rs4938723 were evaluated in tumor tissues of 148 patients, and miR-34b expression in 123 HPV-negative OSCC. For risk assessment, the control group was comprised of 175 healthy individuals. MiR-34b/c promoter hypermethylation was determined by methylation-specific PCR. Gene expression, genotyping and HPV screening was assessed by Q-PCR. The data from our hospital cohort indicated that miR-34b/c DNA methylation was associated with nodal status (p = 0.048), and predicted the shorter overall survival of HPV-negative OSCC patients (p = 0.008). Down-regulated miR-34b/c expression was associated with smoking (p = 0.047), alcohol use (p = 0.009), stage (p = 0.025), recurrences (p = 0.000), and a poor survival (p = 0.00029). Median values of miR-34b expression were significantly lower in advanced stages III/IV as opposed to stage I/II, p = 0.006, and in nodal positive vs negative patients (p = 0.045). TCGA data also indicated that tumors with stage I-III expressed significantly higher levels of miR-34b, compared to tumors with stage IV (p = 0.035), Low miR-34b/c expression was associated with poor survival in smokers (p = 0.001) and patients with tongue carcinomas (p = 0.00003), and TCGA analysis confirmed these findings although miR-34b expression and miR-34b/c methylation were not associated with survival outcome in the whole TCGA cohort. A significant negative miR-34b/c expression-methylation correlation was observed in our hospital cohort (p = 0.017) and in TCGA cohort. Pre-miR-34b/c polymorphism was not associated with oral cancer risk. Our findings indicate that miR-34b/c hypermethylation and low miR-34b expression could promote the progression and predict the poor prognosis for HPV-negative OSCC, which suggests miR-34b/c as a promising biomarker and therapeutic target for OSCC in the future.

Investigation of miR-21-5p Key Target Genes and Pathways in Head and Neck Squamous Cell Carcinoma Based on TCGA Database and Bioinformatics Analysis

Aim: Head and neck squamous cell carcinoma (HNSCC) is the sixth most commonly diagnosed malignancy worldwide. Overexpressed of microRNA-21-5p (miR-21-5p) has been reported to be involved in the development of HNSCC. However, the role of miR-21-5p in HNSCC is still not fully elucidated. The purpose of this study was to explore the underlying molecular mechanisms of miR-21-5p in HNSCC. Methods: RT-qPCR was used to determine the differential expression levels of miR-21-5p in tissue samples of HNSCC patients. Meta-analysis was performed based on miRNA expression data collected from the Gene Expression Omnibus (GEO) database, The Cancer Genome Atlas (TCGA), and published articles to evaluate the expression of miR-21-5p in HNSCC. We investigated the biological function of miR-21-5P by gene ontology enrichment and target prediction analysis. Furthermore, RT-qPCR and IHC were conducted to verify the expression of target genes. Finally, Kaplan–Meier survival analysis was performed to assessed the prognostic value of the putative miR-21-5p target genes. Results: MiR-21-5p was significantly overexpressed in HNSCC compared to healthy tissues (P < .05) and showed potent predictive power with a summary receiver operating characteristic of 0.90. Meanwhile, the expression of miR-21-5p was significantly correlated with tumor stage, T stage and smoking in HNSCC (P < .05). A total of 71 down-regulated genes, both HNSCC-related and miR-21-p5-related, were obtained from the analytical integration. Two predicted genes (ADH7, RDH12) were down-regulated in HNSCC, and significantly negatively correlated with miR-21-5p. IHC and RT-qPCR demonstrated that the expression of ADH7 and RDH12 in HNSCC samples was significantly lower than control. And high expression of ADH7 was associated with better DFS of HNSCC patients. Conclusions: miR-21-5p may target at ADH7, RDH12 and participate in regulation of retinol metabolism, which might affect the prognosis of HNSCC. High expression of ADH7 may indicate better prognosis in HNSCC patients.

Bile reflux and hypopharyngeal cancer (Review)

Laryngopharyngeal reflux, a variant of gastroesophageal reflux disease, has been considered a risk factor in the development of hypopharyngeal cancer. Bile acids are frequently present in the gastroesophageal refluxate and their effect has been associated with inflammatory and neoplastic changes in the upper aerodigestive tract. Recent in vitro and in vivo studies have provided direct evidence of the role of acidic bile refluxate in hypopharyngeal carcinogenesis and documented the crucial role of NF-κB as a key mediator of early oncogenic molecular events in this process and also suggested a contribution of STAT3. Acidic bile can cause premalignant changes and invasive squamous cell cancer in the affected hypopharynx accompanied by DNA damage, elevated p53 expression and oncogenic mRNA and microRNA alterations, previously linked to head and neck cancer. Weakly acidic bile can also increase the risk for hypopharyngeal carcinogenesis by inducing DNA damage, exerting anti-apoptotic effects and causing precancerous lesions. The most important findings that strongly support bile reflux as an independent risk factor for hypopharyngeal cancer are presented in the current review and the underlying mechanisms are provided.

The scope of liquid biopsy in the clinical management of oral cancer

Oral squamous cell carcinoma (OSCC) is one of the most prevalent forms of head and neck cancer, and it remains a leading cause of death in developing countries. Failure to detect the disease at an early stage is the main reason for the lack of improvement in the overall survival rate over the decades. Even though tissue biopsy is considered as the gold standard for diagnosis and molecular workup, it is an invasive, expensive and time-consuming procedure. Besides, it may not indicate the genetic status of the entire tumour owing to the heterogeneity of the cancer. In this context, liquid biopsy could be quite useful as it provides a more representative picture of the circulating tumour cells, circulating tumour DNA, circulating RNA, and tumour-derived exosomes obtained from all types of body fluids. This technique provides real-time assessment of variations in the molecular profile of the whole tumour and enables the serial monitoring of the disease status. The method has many advantages, such as easy accessibility, reliability, reproducibility and the possibility for early detection of the disease. However, the concept is still in its infancy, and the research on its application in various tumours including OSCC is rapidly progressing.

miRNAs as Biomarkers for Diagnosing and Predicting Survival of Head and Neck Squamous Cell Carcinoma Patients

Simple Summary

Head and Neck Squamous Cell Carcinoma (HNSCC) is the sixth most common cancer worldwide. It arises from the epithelium of the upper aerodigestive tract. Increasing evidence suggests that there is a significant role of microRNAs in HNSCC formation and progression. The aim of this study was to explore and compare the expression of HNSCC related miRNAs in tumor vs neighboring healthy tissue of HNSCC patients with tumors located in either the oral cavity, oropharynx, or larynx. Our results demonstrated that expression of these miRNAs was significantly different not only between healthy and tumor tissues, but also among tumor locations. Further analysis indicated that microRNA expression could be used to distinguish between tumor and healthy tissues, and prognose the overall survival of patients.

Abstract

Head and Neck Squamous Cell Carcinoma (HNSCC) is the sixth most common cancer worldwide. These tumors originate from epithelial cells of the upper aerodigestive tract. HNSCC tumors in different regions can have significantly different molecular characteristics. While many microRNAs (miRNAs) have been found to be involved in the regulation of the carcinogenesis and pathogenesis of HNSCC, new HNSCC related miRNAs are still being discovered. The aim of this study was to explore potential miRNA biomarkers that can be used to diagnose HNSCC and prognose survival of HNSCC patients. For this purpose, we chose a panel of 12 miRNAs: miR-146a-5p, miR-449a, miR-126-5p, miR-34a-5p, miR-34b-5p, miR-34c-5p, miR-217-5p, miR-378c, miR-6510-3p, miR-96-5p, miR-149-5p, and miR-133a-5p. Expression of these miRNAs was measured in tumor tissue and neighboring healthy tissue collected from patients diagnosed with HNSCC (n = 79) in either the oral cavity, oropharynx, or larynx. We observed a pattern of differentially expressed miRNAs at each of these cancer locations. Our study showed that some of these miRNAs, separately or in combination, could serve as biomarkers distinguishing between healthy and tumor tissue, and their expression correlated with patients’ overall survival.

Systemic Investigation Identifying Salivary miR-196b as a Promising Biomarker for Early Detection of Head-Neck Cancer and Oral Precancer Lesions

Background: Liquid biopsy is a rapidly growing field, for it may provide a minimally invasive way to acquire pathological data for personalized medicine. This study developed a systemic strategy to discover an effective salivary biomarker for early detection of patients with head-neck squamous carcinoma (HNSC) and oral precancer lesion (OPC). Methods: A total of 10 miRNAs were examined in parallel with multiple independent cohorts. These included a training set of salivary samples from HNSC patients, the TCGA-HNSC and GSE31277 cohorts to differentiate miRNAs between tumor and normal tissues, and groups of salivary samples from healthy individuals, patients with HNSC and OPC. Results: The combined results from the salivary training set and the TCGA-HNSC cohort showed that four miRNAs (miR-148b, miR-155, miR-196b, and miR-31) consistently increased in HNSC patients. Further integration with the GSE31277 cohort, two miRNAs (miR-31 and miR-196b) maintained at high significances. Further assessment showed that salivary miR-196b was a prominent diagnostic biomarker, as it remarkably discriminated between healthy individuals and patients with HNSC (p < 0.0001, AUC = 0.767, OR = 5.64) or OPC (p < 0.0001, AUC = 0.979, OR = 459). Conclusion: Salivary miR-196b could be an excellent biomarker for diagnosing OPC and early detection of HNSC. This molecule may be used for early screening high-risk groups of HNSC.

MicroRNAs in head and neck squamous cell carcinoma: a possible challenge as biomarkers, determinants for the choice of therapy and targets for personalized molecular therapies

Head and neck squamous cell carcinoma (HNSCC) are referred to a group of heterogeneous cancers that include structures of aerodigestive tract such as oral and nasal cavity, salivary glands, oropharynx, pharynx, larynx, paranasal sinuses, and local lymph nodes. HNSCC is characterized by frequent alterations of several genes such as TP53, PIK3CA, CDKN2A, NOTCH1, and MET as well as copy number increase in EGFR, CCND1, and PIK3CA. These genomic alterations play a role in terms of resistance to chemotherapy, molecular targeted therapy, and prediction of patient outcome. MicroRNAs (miRNAs) are small single-stranded noncoding RNAs which are about 19-25 nucleotides. They are involved in the tumorigenesis of HNSCC including dysregulation of cell survival, proliferation, cellular differentiation, adhesion, and invasion. The discovery of the stable presence of the miRNAs in all human body made them attractive biomarkers for diagnosis and prognosis or as targets for novel therapeutic ways, enabling personalized treatment for HNSCC. In recent times the number of papers concerning the characterization of miRNAs in the HNSCC tumorigenesis has grown a lot. In this review, we discuss the very recent studies on different aspects of miRNA dysregulation with their clinical significance and we apologize for the many past and most recent works that have not been mentioned. We also discuss miRNA-based therapy that are being tested on patients by clinical trials.

Weakly Acidic Bile Is a Risk Factor for Hypopharyngeal Carcinogenesis Evidenced by DNA Damage, Antiapoptotic Function, and Premalignant Dysplastic Lesions In Vivo

Simple Summary

The etiologic role of biliary reflux in hypopharyngeal cancer is supported by clinical data. Although, reflux episodes often occur at pH 4.0, they can also occur at weakly acidic pH (5.5–6.0). The carcinogenic effect of bile at strongly acidic pH (pH 3.0) was recently documented in vivo. Here, we provide novel in vivo evidence that a weakly acidic pH of 5.5, similarly to a strongly acidic pH of 3.0, increases the risk of bile-related hypopharyngeal neoplasia. We document that chronic exposure of hypopharyngeal mucosa to bile at pH 5.5 promotes premalignant lesions with DNA damage, NF-κB activation, and deregulated mRNA and miRNA phenotypes, including Bcl-2 and miR-451a. The oncogenic effects of bile over a wider pH range suggests that antacid therapy may be insufficient to fully modify the effects of a bile induced oncogenic effect.

Abstract

Background: There is recent in vivo discovery documenting the carcinogenic effect of bile at strongly acidic pH 3.0 in hypopharynx, while in vitro data demonstrate that weakly acidic bile (pH 5.5) has a similar oncogenic effect. Because esophageal refluxate often occurs at pH > 4.0, here we aim to determine whether weakly acidic bile is also carcinogenic in vivo. Methods: Using 32 wild-type mice C57B16J, we performed topical application of conjugated primary bile acids with or without unconjugated secondary bile acid, deoxycholic acid (DCA), at pH 5.5 and controls, to hypopharyngeal mucosa (HM) twice per day, for 15 weeks. Results: Chronic exposure of HM to weakly acidic bile, promotes premalignant lesions with microinvasion, preceded by significant DNA/RNA oxidative damage, γH2AX (double strand breaks), NF-κB and p53 expression, overexpression of Bcl-2, and elevated Tnf and Il6 mRNAs, compared to controls. Weakly acidic bile, without DCA, upregulates the “oncomirs”, miR-21 and miR-155. The presence of DCA promotes Egfr, Wnt5a, and Rela overexpression, and a significant downregulation of “tumor suppressor” miR-451a. Conclusion: Weakly acidic pH increases the risk of bile-related hypopharyngeal neoplasia. The oncogenic properties of biliary esophageal reflux on the epithelium of the upper aerodigestive tract may not be fully modified when antacid therapy is applied. We believe that due to bile content, alternative therapeutic strategies using specific inhibitors of relevant molecular pathways or receptors may be considered in patients with refractory GERD.

Insight toward the MicroRNA Profiling of Laryngeal Cancers: Biological Role and Clinical Impact

Head and neck squamous cell carcinoma (HNSCC), a heterogeneous disease arising from various anatomical locations including the larynx, is a leading cause of death worldwide. Despite advances in multimodality treatment, the overall survival rate of the disease is still largely dismal. Early and accurate diagnosis of HNSCC is urgently demanded in order to prevent cancer progression and to improve the quality of the patient's life. Recently, microRNAs (miRNAs), a family of small non-coding RNAs, have been widely reported as new robust tools for prediction, diagnosis, prognosis, and therapeutic approaches of human diseases. Abnormally expressed miRNAs are strongly associated with cancer development, resistance to chemo-/radiotherapy, and metastatic potential through targeting a large variety of genes. In this review, we summarize on the recent reports that emphasize the pivotal biological roles of miRNAs in regulating carcinogenesis of HNSCC, particularly laryngeal cancer. In more detail, we report the characterized miRNAs with an evident either oncogenic or tumor suppressive role in the cancers. In addition, we also focus on the correlation between miRNA deregulation and clinical relevance in cancer patients. On the basis of intriguing findings, the study of miRNAs will provide a new great opportunity to access better clinical management of the malignancies.

A Novel Tumor Suppressor SPINK5 Serves as an Independent Prognostic Predictor for Patients with Head and Neck Squamous Cell Carcinoma

BACKGROUND

In our previous study, serine protease inhibitor Kazal-type 5 (SPINK5), which encodes the product of serine protease inhibitor lymphoepithelial Kazal-type-related inhibitor (LEKTI) was found to be down-regulated in head and neck squamous cell carcinoma (HNSCC) using oligonucleotide microarrays. However, the function and clinical implications of SPINK5/LEKTI remain obscure in HNSCC.

METHODS

The endogenous expression level of SPINK5/LEKTI was further verified in 9 HNSCC cell lines and HNSCCs by means of reverse transcription-polymerase chain reaction, real-time PCR, Western blotting and immunohistochemistry. The biological function of SPINK5/LEKTI was investigated in vitro and in vivo experiments. Kaplan-Meier survival analysis and Cox proportional hazards regression model were used to determine the correlation between SPINK5/LEKTI expression and clinical outcome.

RESULTS

Down-regulation expression of SPINK5/LEKTI was found in six out of nine HNSCC cell lines and in 85.7% HNSCC specimens (P<0.0001). Upon silencing of SPINK5/LEKTI, the cell proliferation, plate colony formation and cell invasion of WU-HN6 cells were significantly increased, while exogenous overexpression of SPINK5/LEKTI, the proliferation, plate colony and invasion of WU-HN13 and HN30 cells were remarkably inhibited with the arrest of G1 cell cycle (P=0.0001, P=0.003, respectively). HNSCC patients with lower LEKTI levels had significantly inferior overall survival compared to those patients with higher LEKTI (P=0.0017) by Kaplan-Meier survival analysis. Univariate and multivariate Cox proportional hazards regression model analysis revealed that LEKTI expression was an independent prognostic predictor for HNSCC patients (HR=0.114, 95% CI:0.044-0.292, P<0.001).

CONCLUSION

Our results demonstrate that SPINK5/LEKTI might be a tumor suppressor in HNSCCs and serve as an independent prognostic predictor for HNSCC patients.

Regulation of Oncogenic Targets by miR-99a-3p (Passenger Strand of miR-99a-Duplex) in Head and Neck Squamous Cell Carcinoma

To identify novel oncogenic targets in head and neck squamous cell carcinoma (HNSCC), we have analyzed antitumor microRNAs (miRNAs) and their controlled molecular networks in HNSCC cells. Based on our miRNA signature in HNSCC, both strands of the miR-99a-duplex (miR-99a-5p: the guide strand, and miR-99a-3p: the passenger strand) are downregulated in cancer tissues. Moreover, low expression of miR-99a-5p and miR-99a-3p significantly predicts poor prognosis in HNSCC, and these miRNAs regulate cancer cell migration and invasion. We previously showed that passenger strands of miRNAs have antitumor functions. Here, we screened miR-99a-3p-controlled oncogenes involved in HNSCC pathogenesis. Thirty-two genes were identified as miR-99a-3p-regulated genes, and 10 genes (STAMBP, TIMP4, TMEM14C, CANX, SUV420H1, HSP90B1, PDIA3, MTHFD2, BCAT1, and SLC22A15) significantly predicted 5-year overall survival. Notably, among these genes, STAMBP, TIMP4, TMEM14C, CANX, and SUV420H1 were independent prognostic markers of HNSCC by multivariate analyses. We further investigated the oncogenic function of STAMBP in HNSCC cells using knockdown assays. Our data demonstrated that the aggressiveness of phenotypes in HNSCC cells was attenuated by siSTAMBP transfection. Moreover, aberrant STAMBP expression was detected in HNSCC clinical specimens by immunohistochemistry. This strategy may contribute to the clarification of the molecular pathogenesis of this disease.

Epigenetic Modifications in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common human malignancy in the world, with high mortality and poor prognosis for patients. Among the risk factors are tobacco and alcohol intake, human papilloma virus, and also genetic and epigenetic modifications. Many studies show that epigenetic events play an important role in HNSCC development and progression, including DNA methylation, chromatin remodeling, histone posttranslational covalent modifications, and effects of non-coding RNA. Epigenetic modifications may influence silencing of tumor suppressor genes by promoter hypermethylation, regulate transcription by microRNAs and changes in chromatin structure, or induce genome instability through hypomethylation. Moreover, getting to better understand aberrant patterns of methylation may provide biomarkers for early detection and diagnosis, while knowledge about target genes of microRNAs may improve the therapy of HNSCC and extend overall survival. The aim of this review is to present recent studies which demonstrate the role of epigenetic regulation in the development of HNSCC.

Increased expression of miR-146a, miR-10b, and miR-21 in cancer stem-like gastro-spheres

BACKGROUND

Gastric cancer remains one of the leading causes of cancer-associated mortalities globally. Accumulating evidence support the presence of gastric cancer stem cells (CSCs) and their role in the pathogenesis and therapeutic challenges of gastric cancer. MicroRNAs (miRNAs) may be influenced by the cellular differentiative state and as critical regulators of the cellular fate in development and cancer, can modulate the behavior of CSCs too. Here, we aimed to investigate the expression relevance of three prognostic miRNAs (miR-21, miR-10b, and miR-146a) in CSCs of AGS and MKN-45 gastric cancer cell lines.

METHODS

Serial sphere-forming assay in serum-free culture medium was used to enrich the cellular population with stem-like properties. Gastro-spheres were characterized by evaluating the stemness gene expression, clonogenicity, and resistance to docetaxel and cisplatin in comparison with their parental cells. The expression level of miRNAs in gastro-spheres and their parental cells was measured using quantitative reverse transcription polymerase chain reaction.

RESULTS

Gastro-spheres from both cell lines exhibit stem-like properties: upregulated stemness associated genes (P < 0.05), more colonogenicity and more resistance to docetaxel (P < 0.05). MKN-45 gastro-spheres exhibited upregulated expression of miR-21 (1.8-folds), miR-10b (1.34-folds) and miR-146a (4.8-folds; P < 0.05) compared with the parental cells. AGS-derived gastro-spheres showed upregulation of miR-21 (4.7-folds; P < 0.01), miR-10b (15.2-folds; P < 0.001) and miR-146a (39.3-folds; P < 0.05).

CONCLUSION

Our data exhibited upregulation of miR-21, miR-10b, and miR-146a in the stem-like gastro-spheres; however; their function in gastric CSCs remains to be verified by further experiments.

In situ measurement of miR-138 expression in oral squamous cell carcinoma tissue supports the role of this microRNA as a tumor suppressor

BACKGROUND

Oral squamous cell carcinoma is the eighth most common cancer worldwide with a relatively high rate of metastasis (~40%). Previously, we showed that microRNA-138 serves as a functional tumor suppressor and plays an important role in oral squamous cell carcinoma metastasis. However, to date, microRNA-138 expression has not been examined in this tumor tissue. Herein, we demonstrated that microRNA-138 expression is downregulated in metastatic oral squamous cell carcinoma specimens using tissue microarray technology with in situ hybridization.

METHODS

The study included 254 oral squamous cell carcinoma patients from two centers (160 from the Chengdu center and 90 from the Guangzhou center) and four healthy volunteers.

RESULTS

Multivariate analysis showed that microRNA-138 expression was independent of tumor stage, age, gender, smoking, and alcohol consumption in oral squamous cell carcinoma patients. Interestingly, patients that expressed lower levels of microRNA-138 (determined by in situ hybridization) were more prone to regional lymph node metastasis and exhibited poorer outcomes. These findings support the role of microRNA-138 as a tumor suppressor in oral squamous cell carcinoma.

CONCLUSION

In summary, the expression level of microRNA-138 is negatively correlated with oral squamous cell carcinoma metastasis; the lower the expression of microRNA-138, the higher the rate of metastasis and the poorer the prognosis of the patients. Therefore, our study confirms that microRNA-138 serves as a tumor suppressor and plays a functional role in oral squamous cell carcinoma tumor metastasis; microRNA-138 constitutes a promising prognosis biomarker and therapeutic target for oral squamous cell carcinoma with metastasis potential.

MicroRNA-98-HMGA2-POSTN signal pathway reverses epithelial-to-mesenchymal transition in laryngeal squamous cell carcinoma

It has been widely considered that reversing epithelial-to-mesenchymal transition (EMT) is a potential access to restrain cancer progression and therapeutic resistance. Here, we aim to uncover the novel mechanisms by which we can reverse EMT and inhibit metastasis in laryngeal squamous cell carcinoma (LSCC). We show that miR-98 is significantly reduced in both LSCC specimens and cell lines. Over-expression of miR-98 inhibits the EMT-related gene expression and metastasis and invasive behavior in LSCC in vitro, as well as reduces lung metastasis in mouse model. In the mechanistically study, miR-98 directly targets HMGA2 in mediating EMT. HMGA2 knock down by si-RNA method declines several EMT-related genes expression and LSCC migration and invasion. In parallel, overexpression of HMGA2 transforms LSCC cells to acquire stem cell-like features. Furthermore, we reveal that HMGA2-mediated EMT is closely linked with the expression of POSTN that inhibits EMT, as a tumor suppressor, by gene profiling analyses. POSTN is transcriptionally repressed by HMGA2. In clinic, the HMGA2 mRNA level is negatively correlated with the miR-98 level in LSCC patient cohort. In conclusion, our study confers a powerful signal: miR-98-HMGA-POSTN in LSCC, which is able to reverse EMT and inhibit metastasis, underlining the therapeutic potential of this signal.

MiR-193a regulates chemoresistance of human osteosarcoma cells via repression of IRS2

Chemoresistance prevents curative potential of chemotherapy in most cases. MicroRNAs (miRNAs) are key players in regulating chemoresistance in osteosarcoma, which is the most common primary bone cancer. Bisulfite sequencing and quantitative real time PCR analyses showed that miR-193a expression is downregulated by DNA hypermethylation at its promoter region in a chemoresistant cell line, SJSA-1, compared to a chemosensitive cell line G-292. Introduction of a miR-193a mimic in SJSA-1 cells or an antagomir into G-292 cells confirmed the role of miR-193a in osteosarcoma chemoresistance. Bioinformatics together with biochemical assays showed that insulin receptor substrate 2 (IRS2) is a target of miR-193a. Our data concludes that miR-193a plays a role in the osteosarcoma chemoresistance and thus might serve as a useful biomarker for osteosarcoma prognosis.

miR-31-5p Is a Potential Circulating Biomarker and Therapeutic Target for Oral Cancer

MicroRNAs have been proposed as novel biomarkers for the diagnosis and treatment of many types of cancer. The levels of five candidate microRNAs (miRNAs) (miR-99a-5p, miR-31-5p, miR-138-5p, miR-21-5p, and miR-375-3p) in sera from oral cancer patients and paired tumor and normal tissues were detected by real-time qPCR. The diagnostic power of these miRNAs was analyzed by receiver operating characteristic (ROC) curves. Patient-derived xenograft (PDX) models of oral cancer were established and utilized to verify the potential therapeutic effect of miR-31-5p. Candidate miRNAs were screened from our previous studies and verified in 11 paired oral cancer and adjacent normal tissues. Only serum miR-31-5p levels were significantly different between oral cancer patients and healthy controls and between pre- and postoperative patients. Based on the logistic regression model, this panel of five miRNAs distinguished oral cancer patients from healthy control, with an area under the ROC curve (AUC) of 0.776 (sensitivity = 76.8% and specificity = 73.6%). Furthermore, a miR-31-5p mimic enhanced the proliferation of normal epithelial cells, and antagomiR-31-5p inhibited the proliferation of oral cancer cells in vitro. In vivo, antagomiR-31-5p significantly inhibited tumor growth in oral cancer PDX models. Our findings suggest that circulating miR-31-5p might act as an independent biomarker for oral cancer diagnosis and could serve as a therapeutic target for oral cancer.

miR-125b suppresses oral oncogenicity by targeting the anti-oxidative gene PRXL2A

Oral squamous cell carcinoma (OSCC) is a globally prevalent malignancy. The molecular mechanisms of this cancer are not well understood and acquire elucidation. Peroxiredoxin like 2A (PRXL2A) has been reported to be an antioxidant protein that protects cells from oxidative stress. Our previous study identified an association between PRXL2A upregulation in OSCC and a worse patient prognosis. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in the modulation of biological/pathological properties. The miR-125 family of genes drive pluripotent regulation across a wide variety of cancers. In this study, we identify the oncogenic eligibility of PRXL2A and clarify miR-125b as its upstream regulator. Downregulation of miR-125b can be observed in OSCC tumors. Lower miR-125b expression in tumors results in a worse patient prognosis at the relatively early stage. Reporter assays are able to validate that PRXL2A is a direct target of miR-125b. Exogenous miR-125b expression in OSCC cells results in increased oxidative stress, increased drug sensitivity, and suppressor activity that is paralleled by the knockout of PRXL2A gene. The suppressor activity of miR-125b is able to be rescued by PRXL2A, which suggests the existence of a miR-125b-PRXL2A regulatory axis that is part of OSCC pathogenesis. Nuclear factor-erythroid 2-related factor 2 (NRF2) was found to be a downstream effector of the miR-125b-PRXL2A cascade. As a whole, this study has pinpointed novel clues demonstrating that downregulation of miR-125b suppressor underlies upregulation of PRXL2A in OSCC, and this then protects the affected tumor cells from oxidative stress.

Knockdown long noncoding RNA nuclear paraspeckle assembly transcript 1 suppresses colorectal cancer through modulating miR-193a-3p/KRAS

The nuclear paraspeckle assembly transcript 1 (abbreviated as NEAT1), a nuclear sufficient long noncoding RNA (abbreviated as lncRNA), has aroused a rising concern in recent years. As uncovered by reports, the increase in NEAT1 is related to the deteriorated prognosis of lung cancer, breast cancer, hepatocellular cancer, and colorectal cancer (abbreviated as CRC). Thus far, the mechanism of NEAT1 has not been elucidated by the existing researches. The impact of knockdown of both NEAT1 and its predicted downstream miR‐193a‐3p in CRC cells was examined here to delve into their interactions and mechanisms. Additionally, the target of miR‐193a‐3p, Kirsten rat sarcoma viral oncogene homolog (abbreviated as KRAS), was also predicted by bioinformatics algorithms. Small interfering RNA and antisense oligonucleotides that inhibit NEAT1, as well as overexpression or knockdown of miR‐193a‐3p, were adequately drawn upon to confirm that NEAT1 serves as a miR‐193a‐3p sponge or competing endogenous RNA, to impact miR‐193a‐3p's further functions, including modulating KRAS proteins, both in vitro and in vivo. Generally, lncRNA NEAT1/hsa‐miR‐193a‐3p/KRAS axis was substantiated in CRC cells and could provide novel insight into both diagnostic and therapeutic advancement in CRC.

Expression levels of miR-34-family microRNAs are associated with TP53 mutation status in head and neck squamous cell carcinoma

PURPOSE

The majority of head and neck squamous cell carcinoma (HNSCC) cases in developing countries are associated with cigarette smoking and TP53 mutations. p53 is a transcription factor that activates downstream genes, including the hsa-miR-34a and hsa-miR-34b/c loci, to achieve cell-cycle arrest, senescence, and/or apoptosis. This study examined the differences in expression levels of miR-34 in HNSCC with or without TP53 mutations.

METHODS

We examined surgically resected tumor samples and normal adjacent tissues from HNSCC in oral cavity, larynx, and hypopharynx for TP53 mutations (exons 5-8) and miR-34 expression levels.

RESULTS

miR-34a, miR-34b, miR-34b*, and miR-34c are significantly up-regulated in tumors with wild-type TP53 genes (n = 23); while such up-regulation is not observed in tumors with mutant TP53 (n = 19). Although expression levels of miR-34-family miRNAs do not correlate with gender, age, or tumor staging, interestingly they are correlated with smoking status and tumor sites. miR-34b/b*/c are up-regulated in tumors from those who ever smoked or recently smoked (quit smoking less than 15 years ago); but such up-regulation was not seen in those who never smoked or quit smoking for at least 15 years. HNSCC of the oral cavity also up-regulated miR-34b/b*/c while no such overexpression was observed in HNSCC of the larynx and hypopharynx.

CONCLUSIONS

Surgically resected HNSCC samples with no TP53 mutations have elevated levels of miR-34a and miR-34b/b*/c, while those with TP53 mutations show no such up-regulation. miR-34b/b*/c expression is also correlated with smoking status and tumor sites.

The expression and biological information analysis of miR-375-3p in head and neck squamous cell carcinoma based on 1825 samples from GEO, TCGA, and peer-reviewed publications

BACKGROUND

The specific expression level and clinical significance of miR-375-3p in HNSCC had not been fully stated, as well as the overall biological function and molecular mechanisms. Therefore, we purpose to carry out a comprehensive meta-analysis to further explore the clinical significance and potential function mechanism of miR-375-3p in HNSCC.

METHODS

HNSCC-related data was gained from Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), and peer-reviewed journals. A meta-analysis was carried out to comprehensively explore the relationship between miR-375-3p expression level and clinicopathological features of HNSCC. And summary receiver operating characteristic (SROC) curve analysis was applied for evaluating disease diagnosis value of miR-375-3p. In addition, a biological pathway analysis was also performed to assess the possible molecular mechanism of miR-375-3p in HNSCC.

RESULTS

A total of 24 available records and references were added into analysis. The overall pooled meta-analysis outcome revealed a relatively lower expression level of miR-375-3p in HNSCC specimens than that in non-cancerous controls (P < 0.001). And SROC curve analysis showed that the pooled area under the SROC curve (AUC) was 0.90 (95%CI: 0.88-0.93). In addition, biological pathway analysis indicated that LAMC1, EDIL3, FN1, VEGFA, IGF2BP2, and IGF2BP3 maybe the latent target genes of miR-375-3p, which were greatly enriched in the pathways of beta3 integrin cell surface interactions and the binding of RNA via the insulin-like growth factor-2 mRNA-binding protein (IGF2BPs/IMPs/VICKZs).

CONCLUSION

MiR-375-3p expression clearly decreased in HNSCC samples compared with non-cancerous controls. Meanwhile, miR-375-3p may serve as a tumor suppressor via regulating tumor-related genes LAMC1, EDIL3, FN1, VEGFA, IGF2BP2, and IGF2BP3 in HNSCC.

Integrative analysis of dysregulated microRNAs and mRNAs in multiple recurrent synchronized renal tumors from patients with von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease is a rare auto-somal dominant syndrome that is the main cause of inherited clear-cell renal cell carcinoma (ccRCC), which generally occurs in the form of multiple recurrent synchronized tumors. Affected patients are carriers of a germline mutation in the VHL tumor suppressor gene. Somatic mutations of this gene are also found in sporadic ccRCC and numerous pan-genomic studies have reported a dysregulation of microRNA (miRNA) expression in these sporadic tumors. In order to investigate the molecular mechanisms underlying the pathogenesis of VHL-associated ccRCC, particularly in the context of multiple tumors, the present study characterized the mRNA and miRNA transcriptome through an integrative analysis compared with sporadic renal tumors. In the present study, two series of ccRCC samples were used. The first set consisted of several samples from different tumors occurring in the same patient, for two independent patients affected with VHL disease. The second set consisted of 12 VHL-associated tumors and 22 sporadic ccRCC tumors compared with a pool of normal renal tissue. For each sample series, an expression analysis of miRNAs and mRNAs was conducted using microarrays. The results indicated that multiple tumors within the kidney of a patient with VHL disease featured a similar pattern of miRNA and gene expression. In addition, the expression levels of miRNA were able to distinguish VHL-associated tumors from sporadic ccRCC, and it was identified that 103 miRNAs and 2,474 genes were differentially expressed in the ccRCC series compared with in normal renal tissue. The majority of dysregulated genes were implicated in 'immunity' and 'metabolism' pathways. Taken together, these results allow a better understanding of the occurrence of ccRCC in patients with VHL disease, by providing insights into dysregulated miRNA and mRNA. In the set of patients with VHL disease, there were few differences in miRNA and mRNA expression, thus indicating a similar molecular evolution of these synchronous tumors and suggesting that the same molecular mechanisms underlie the pathogenesis of these hereditary tumors.

Biological role and clinical value of miR-99a-5p in head and neck squamous cell carcinoma (HNSCC): A bioinformatics-based study

MicroRNAs (miRNAs) are confirmed to be tumor promoters or suppressors in multiple squamous cell carcinomas (SCCs). miR‐99a‐5p has been demonstrated to be downregulated in cancerous tissues, but its functional role in head and neck SCC (HNSCC) and its mechanism of action have not been fully elucidated. Here, we studied the expression of miR‐99a‐5p in HNSCC and performed a clinical value assessment and then extracted mature expression data from The Cancer Genome Atlas (TCGA) and microarrays from Gene Expression Omnibus (GEO). Furthermore, biological analysis was constructed via online prediction tools. The results revealed that miR‐99a‐5p expression was markedly lower in HNSCC tissues than in normal tissues, which also showed significance in the prognosis of HNSCC. However, its diagnostic value could not be verified due to the lack of body fluid samples. Additionally, miR‐99a‐5p was expressed at higher levels in patients with low histological grade neoplasms than those with high histological grade neoplasms. The age of the patient might also be a possible clinical parameter affecting miR‐99a‐5p expression. Furthermore, miR‐99a‐5p significantly influenced HNSCC progression by regulating the PI3K‐Akt signaling pathway, in which the key target genes were upregulated in 519 HNSCC tissues compared to 44 normal tissues, as determined by the Gene Expression Profiling Interactive Analysis (GEPIA). In conclusion, our study may provide insights into the expression and mechanism of miR‐99a‐5p in HNSCC. Further studies are required to elucidate the role of miR‐99a‐5p and its potential clinical applications for HNSCC.

A Noninvasive Test for MicroRNA Expression in Oral Squamous Cell Carcinoma

MicroRNAs have recently been proposed as non-invasive biomarkers in Oral Squamous Cell Carcinoma (OSCC). The aim of this study was to analyze the expression of a panel of miRNAs in epithelial cells collected by oral brushing from OSCCs from regenerative areas after OSCC surgical resection and from their respective normal distant mucosa. Oral brushing specimens were collected from 24 healthy donors, 14 OSCC patients with specimens from tumour and normal distant mucosa, and from 13 patients who had OSCC resection, with samples from regenerative areas after OSCC resection and normal distant mucosa. Expression levels of eight targets (miR-21, miR-375, miR-345, miR-181b, miR-146a, miR-649, miR-518b, and miR-191) were evaluated by real-time Polymerase Chain Reaction (PCR). A highly significant between-group difference was found for miR-21 (F = 6.58, p < 0.001), miR-146a (F = 6.974, p < 0.001), and miR-191 (F = 17.07, p < 0.001). The major difference was observed between samples from healthy donors and from OSCC brushing, whereas no significant differences were observed between areas infiltrated by OSCC and their respective normal distant mucosa. Furthermore, altered expression of miR-146a and miR-191 was also observed in regenerative areas after OSCC resection.

CONCLUSIONS

Oral brushing could be proposed as a noninvasive method to study microRNA expression in oral mucosa in OSCC patients.

[MicroRNA-218 promotes osteosarcoma cell apoptosis by down-regulating oncogene B lymphoma mouse Moloney leukemia virus insertion region 1]

OBJECTIVE

To investigate the tumor-suppressing effect of microRNA-218 (miR-218) in osteosarcoma (OS) and explore its molecular mechanism.

METHODS

We examined the expression levels of miR-218 in 68 pairs of OS and adjacent tissue samples using qRT-PCR.Cultured human OS cell line Saos-2 was transfected with miR-218 mimics or anti-miR-218 mimics, and the cell apoptosis was assessed using CCK-8 assay, annexin V-FITC staining and Western blotting.We also analyzed the potential functional targets of miR-218 in Saos-2 cells using luciferase assay, qRT-PCR and Western blotting.

RESULTS

The expression level of miR-218 was lowered by at least 8 folds in OS tissues as compared with the adjacent tissues.In cultured Saos-2 cells, transfection with miR-218 mimics for 24, 36, and 48 h resulted in a significant reduction in the cell viability, while transfection with anti-miR-218 mimics significantly increased the cell viability.The cells transfected with miR-218 mimics showed an obviously enhanced expression of cleaved poly (ADP-ribose) polymerase (C-PARP) as compared with the cells transfected with anti-miR-218 mimics and the control cells.Flow cytometry demonstrated obviously increased apoptosis of the cells following miR-218 mimics transfection.We identified the oncogene B lymphoma mouse Moloney leukemia virus insertion region 1 (BMI-1) as a specific target of miR-218 in Saos-2 cells. BMI-1 expressions at both the mRNA and protein levels were significantly reduced in Saos-2 cells overexpressing miR-218 but increased in the cells with miR-218 knockdown as compared to the control cells.Luciferase reporter assay indicated that miR-218 directly inhibited the expression of BMI-1 via binding to its 3'-UTR in OS cells.

CONCLUSION

miR-218 can promote OS cell apoptosis and plays the role as a tumor suppressor by down-regulating BMI-1.

ZBTB7/miR-137 Autoregulatory Circuit Promotes the Progression of Renal Carcinoma

Renal carcinoma greatly threatens human health, but the involved molecular mechanisms are far from complete understanding. As a master oncogene driving the initiation of many other cancers, ZBTB7 has not been established to be associated with renal cancer. Our data revealed that ZBTB7 is highly expressed in renal carcinoma specimens and cell lines, compared with normal cells. The silencing of ZBTB7 suppressed the proliferation and invasion of renal cancer cells. ZBTB7 overexpression rendered normal cells with higher proliferation rates and invasiveness. An animal study further confirmed the role of ZBTB7 in the growth of renal carcinoma. Moreover, miR-137 was identified to negatively regulate the expression of ZBTB7, and its abundance is inversely correlated with that of ZBTB7 in renal carcinoma specimens and cell lines. ZBTB7 overexpression may be induced by miR-137 downregulation. Interestingly, ZBTB7 can also suppress miR-137 expression by binding to its recognition site within the miR-137 promoter region. Taken together, we identified an autoregulatory loop consisting of ZBTB7 and miR-137 in gastric cancers, and targeting this pathway may be an effective strategy for renal carcinoma cancer therapy.

Involvement of aberrantly expressed microRNAs in the pathogenesis of head and neck squamous cell carcinoma

MicroRNAs (miRNAs) are small noncoding RNAs that act as fine-tuners of the post-transcriptional control of protein-coding or noncoding RNAs by repressing translation or cleaving RNA transcripts in a sequence-dependent manner in cells. Accumulating evidence have been indicated that aberrantly expressed miRNAs are deeply involved in human pathogenesis, including cancers. Surprisingly, these small, single-stranded RNAs (18-23 nucleotides) have been shown to function as antitumor or oncogenic RNAs in several types of cancer cells. A single miRNA has regulating hundreds or thousands of different mRNAs, and individual mRNA has been regulated by multiple different miRNAs in normal cells. Therefore, tightly controlled RNA networks can be disrupted by dysregulated of miRNAs in cancer cells. Investigation of novel miRNA-mediated RNA networks in cancer cells could provide new insights in the field of cancer research. In this review, we focus on head and neck squamous cell carcinoma (HNSCC) and discuss current findings of the involvement of aberrantly expressed miRNAs in the pathogenesis of HNSCC.

In Vivo Short-Term Topical Application of BAY 11-7082 Prevents the Acidic Bile-Induced mRNA and miRNA Oncogenic Phenotypes in Exposed Murine Hypopharyngeal Mucosa

PURPOSE: Bile-containing gastroesophageal reflux may promote cancer at extraesophageal sites. Acidic bile can accelerate NF-κB activation and molecular events, linked to premalignant changes in murine hypopharyngeal mucosa (HM). We hypothesize that short-term in vivo topical application of NF-κB inhibitor BAY 11-7082 can prevent acidic bile–induced early preneoplastic molecular events, suggesting its potential role in disease prevention. EXPERIMENTAL DESIGN: We topically exposed HM (C57Bl/6j wild-type) to a mixture of bile acids at pH 3.0 with and without BAY 11-7082 3 times/day for 7 days. We used immunofluorescence, Western blotting, immunohistochemistry, quantitative polymerase chain reaction, and polymerase chain reaction microarrays to identify NF-κB activation and its associated oncogenic mRNA and miRNA phenotypes, in murine hypopharyngeal cells in vitro and in murine HM in vivo. RESULTS: Short-term exposure of HM to acidic bile is a potent stimulus accelerating the expression of NF-κB signaling (70 out of 84 genes) and oncogenic molecules. Topical application of BAY 11-7082 sufficiently blocks the effect of acidic bile. BAY 11-7082 eliminates NF-κB activation in regenerating basal cells of acidic bile–treated HM and prevents overexpression of molecules central to head and neck cancer, including bcl-2, STAT3, EGFR, TNF-α, and WNT5A. NF-κB inhibitor reverses the upregulated “oncomirs” miR-155 and miR-192 and the downregulated “tumor suppressors” miR-451a and miR-375 phenotypes in HM affected by acidic bile. CONCLUSION: There is novel evidence that acidic bile–induced NF-κB–related oncogenic mRNA and miRNA phenotypes are generated after short-term 7-day mucosal exposure and that topical mucosal application of BAY 11-7082 can prevent the acidic bile–induced molecular alterations associated with unregulated cell growth and proliferation of hypopharyngeal cells.

MicroRNA meta-signature of oral cancer: evidence from a meta-analysis

AIM

It was the aim of the study to identify commonly deregulated miRNAs in oral cancer patients by performing a meta-analysis of previously published miRNA expression profiles in cancer and matched normal non-cancerous tissue in such patients.

MATERIAL AND METHODS

Meta-analysis included seven independent studies analyzed by a vote-counting method followed by bioinformatic enrichment analysis.

RESULTS

Amongst seven independent studies included in the meta-analysis, 20 miRNAs were found to be deregulated in oral cancer when compared with non-cancerous tissue. Eleven miRNAs were consistently up-regulated in three or more studies (miR-21-5p, miR-31-5p, miR-135b-5p, miR-31-3p, miR-93-5p, miR-34b-5p, miR-424-5p, miR-18a-5p, miR-455-3p, miR-450a-5p, miR-21-3p), and nine were down-regulated (miR-139-5p, miR-30a-3p, miR-376c-3p, miR-885-5p, miR-375, miR-486-5p, miR-411-5p, miR-133a-3p, miR-30a-5p). The meta-signature of identified miRNAs was functionally characterized by KEGG enrichment analysis. Twenty-four KEGG pathways were significantly enriched, and TGF-beta signaling was the most enriched signaling pathway. The highest number of meta-signature miRNAs was involved in the sphingolipid signaling pathway. Natural killer cell-mediated cytotoxicity was the pathway with most genes regulated by identified miRNAs. The rest of the enriched pathways in our miRNA list describe different malignancies and signaling.

CONCLUSIONS

The identified miRNA meta-signature might be considered as a potential battery of biomarkers when distinguishing oral cancer tissue from normal, non-cancerous tissue. Further mechanistic studies are warranted in order to confirm and fully elucidate the role of deregulated miRNAs in oral cancer.

The clinical value of miR-193a-3p in non-small cell lung cancer and its potential molecular mechanism explored in silico using RNA-sequencing and microarray data

miR‐193a‐3p is a tumor‐related miRNA playing an essential role in tumorigenesis and progression of non‐small cell lung cancer (NSCLC). The objective of the present study was to investigate the relationship between miR‐193a‐3p expression and clinical value and to further explore the potential signaling of miR‐193a‐3p in the carcinogenesis of NSCLC. RNA‐sequencing and microarray data were collected from the databases GEO, ArrayExpress and The Cancer Genome Atlas (TCGA). Furthermore, in silico assessments were performed to analyze the prospective pathways and networks of the target genes of miR‐193a‐3p. In total, 453 cases of NSCLC patients and 476 normal controls were included in blood samples, while 920 cases of NSCLC patients and 406 normal controls were included in tissue samples. The pooled positive likelihood ratio, the pooled negative likelihood ratio and the pooled diagnostic odds ratio were calculated to reflect the diagnostic value of miR‐193a‐3p in blood and tissue samples. Moreover, the areas under the curve of the summary receiver operating characteristic curve of blood and tissue were 0.64 and 0.79, respectively. In addition, we found a lower level of miR‐193a in NSCLC tissues than in non‐cancerous controls based on TCGA. A gene ontology (GO) enrichment analysis demonstrated that miR‐193a‐3p could be related to key signaling pathways in NSCLC. Also, several vital pathways were illustrated by KEGG. Lower expression of miR‐193a‐3p in tissue samples of NSCLC may be associated with tumorigenesis and be a predictor of deterioration of NSCLC patients, and pathway analysis revealed crucial signaling pathways correlated with the incidence and progress of NSCLC.

miR-486-3p, miR-139-5p, and miR-21 as Biomarkers for the Detection of Oral Tongue Squamous Cell Carcinoma

Oral tongue squamous cell carcinoma (TSCC) is a complex disease with extensive genetic and epigenetic defects, including microRNA deregulation. The aims of the present study were to test the feasibility of performing the microRNA profiling analysis on archived TSCC specimens and to assess the potential diagnostic utility of the identified microRNA biomarkers for the detection of TSCC. TaqMan array-based microRNA profiling analysis was performed on 10 archived TSCC samples and their matching normal tissues. A panel of 12 differentially expressed microRNAs was identified. Eight of these differentially expressed microRNAs were validated in an independent sample set. A random forest (RF) classification model was built with miR-486-3p, miR-139-5p, and miR-21, and it was able to detect TSCC with a sensitivity of 100% and a specificity of 86.7% (overall error rate = 6.7%). As such, this study demonstrated the utility of the archived clinical specimens for microRNA biomarker discovery. The feasibility of using microRNA biomarkers (miR-486-3p, miR-139-5p, and miR-21) for the detection of TSCC was confirmed.

Role of non-coding RNAs in head and neck squamous cell carcinoma: A narrative review

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with high recurrence, metastasis, and poor treatment outcome. Recent studies have reported that non-coding RNA (ncRNA) might play critical role in regulating different types of cancer. MicroRNAs (miRs) are short ncRNAs (20-25 nucleotides) responsible for post-transcriptional regulation of gene expression and may have a role in oncogenesis by acting as oncomiRs or tumor suppressor miRs. Long non-coding RNAs (lncRNAs) are heterogenous group of ncRNAs more than 200 nucleotides long, can act in cis and/or in trans, and have been also implicated in carcinogenesis. These molecules have been suggested to be promising candidates as diagnostic and prognostic biomarkers and for development of novel therapeutic approaches. In this review, we have summarized recent findings on role of these ncRNAs in HPV-negative (HPV-ve) and HPV-positive (HPV+ve) HNSCC. The available literature supports differential expression of both microRNAs and long non-coding RNAs, which include oncogenic ncRNAs (miR-21, miR-31, miR-155, miR-211, HOTAIR, and MALAT1) and tumor suppressor ncRNAs (let7d, miR-17, miR-375, miR-139, and MEG3) in HPV+ve HNSCC tumors as compared to HPV-ve tumors and they have distinct role in the pathophysiology of these two types of HNSCCs.

Deregulation of selected microRNAs in sinonasal carcinoma: Value of miR-21 as prognostic biomarker in sinonasal squamous cell carcinoma

BACKGROUND

Tumors occurring in the sinonasal area are characterized by unfavorable outcome due to difficult diagnosis, treatment, and prognosis of the disease corresponding with the anatomic complexity of the area.

METHODS

We used quantitative real-time polymerase chain reaction (PCR) to compare relative expression of miR-21, miR-141, and miR-200c in 70 formalin-fixed, paraffin-embedded samples of sinonasal carcinoma tissue (majority of squamous cell carcinoma [SCC] samples) with 17 control samples of sinonasal tissue.

RESULTS

Our data showed significant upregulation of miR-21 in sinonasal cancer tissue. Expression levels of miR-141 and miR-200c were below detectable levels in both sinonasal cancer samples and healthy tissue. Kaplan-Meier analysis with log-rank survival showed that patients with SCC with high expression of miR-21 (highest quartile) had impaired survival close to reaching statistical significance (P = .0630).

CONCLUSION

Our results suggest that miR-21 upregulation is involved in tumorigenesis of sinonasal carcinoma and that it is associated with poor prognosis. Thus, miR-21 could be used as a valuable prognostic biomarker.

miR-137 acts as a tumor suppressor via inhibiting CXCL12 in human glioblastoma

Up to date, miR-137 has been demonstrated as a tumor suppressor in many kinds of human malignancies. In the present study, we conducted transfection, western blot and RT-PCR to explore the role of miR-137 in the development of human glioblastoma (GBM). Here, we found that miR-137 expression was obviously down-regulated in GBM tissues and cells rather than matched non-tumor tissues and NHA cells. However, the expression of C-X-C motif ligand 12 (CXCL12) mRNA and protein were up-regulated in GBM tissues and cells. In vitro, miR-137 mimics inhibited GBM cell proliferation, migration and invasion, and the 3′-untranslated regions (3′-UTR) of CXCL12 were a direct target of miR-137. In addition, miR-137 mimics also inhibited the expression of EGFR, Bcl-2 and MMP2/9 proteins, but increased the expression of Bax protein. Notably, CXCL12 over-expression attenuated miR-137-inhibited cell proliferation and invasion, while CXCL12 siRNAs promoted miR-137 inhibition effects. In vivo, miR-137 mimics also suppressed tumor growth in nude mice xenograft model. In conclusion, miR-137 serves as a tumor suppressor by inhibition of CXCL12 in human GBM. Thus, miR-137-CXCL12 can be recommended as a useful and effective target for treatment of GBM.

MiR-223-3p inhibits angiogenesis and promotes resistance to cetuximab in head and neck squamous cell carcinoma

MicroRNAs (miRs) participate in tumor growth and dissemination by regulating expression of various target genes. MiR-223-3p is suspected of being involved in head and neck squamous cell carcinoma (HNSCC) growth although its precise role has not been elucidated. In this study, we showed that miR-223-3p is present in biopsies of HNSCC patients and that its presence is correlated with high neutrophil infiltrate. We found that overexpression of miR-223-3p slightly increased proliferation of the CAL27 squamous carcinoma cell line both in vitro and in vivo. Moreover, miR-223-3p induced CAL27 apoptosis in an orthotopic xenograft mouse model, counteracting the proliferative effect and resulting in no impact on overall tumor growth. We analyzed the effect of miR-223-3p overexpression on signaling pathways and showed that it induced pERK2, pAKT and AKT, consistent with an increase in cell proliferation. In addition, we found that miR-223-3p reduced the STAT3 level correlating with increased cell apoptosis and inhibited vasculature formation. In HNSCC tissues, miR-223-3p expression was inversely correlated to CD31, highlighting the relationship between miR-223 and vessel formation. Finally, we studied the effect of miR-223-3p on response to selected anticancer agents and showed that cells expressing miR-223-3p are more resistant to drugs, notably cetuximab.

In conclusion, our study is the first to show the antiangiogenic properties of miR-223-3p in HNSCC patients and to question whether expression levels of miR-223-3p can be evaluated as an indicator of eligibility for non-treatment of HNSCC patients with cetuximab.

Comparison of microRNA profiles between benign and malignant salivary gland tumors in tissue, blood and saliva samples: a prospective, case-control study

Introduction

Salivary gland tumors (SGTs) are rare head and neck malignancies consisting of a spectrum of tumors with different biological behaviors.

Objective

In this study we aimed to find out differential expression of microRNA profiles between benign and malignant SGTs.

Methods

We investigated the possible role of 95 microRNAs in the 20 patients with salivary gland tumors with comparison of 17 patients without malignancy or salivary gland diseases. Sixteen of the tumors were benign (seven pleomorphic adenomas, nine Warthin tumors), four of them were malignant (two squamous cell carcinomas, one high grade mucoepidermoid carcinoma, one adenocarcinoma). Serum and saliva samples were collected from both patients and control group. Tissue samples of tumor masses were also collected from patient group.

Results

Among studied microRNAs miR-21, miR-23a, miR-27a, miR-223, miR-125b, miR-126, miR-146a, miR-30e were down regulated in the benign group compared to control group in the serum samples (p-values are 0.04, 0.00005, 0.00005, 0.0022, 0.031, 0.00008, 0.044, and 0.0007, respectively). When tissue samples were studied miR-21, miR-31, miR-199a-5p, miR-146b, miR-345 were up-regulated in the malignant group compared to benign group (p values are 0.006, 0.02, 0.013, 0.013, 0.041, respectively). miR-30e showed statistically significant up-regulation in malignant tumor group's plasma samples compared to benign group (p = 0.034). There was no statistically significant difference in saliva samples between groups.

Conclusion

Our results showed that different microRNAs may play role in salivary tumor pathogenesis according to biological behavior. Although there was no difference in saliva samples between groups, according to tissue and serum samples miR-21 and 30e may have an important role; since they were down-regulated in benign tumors whereas up-regulated in malignant ones.

MicroRNA-137 chemosensitizes colon cancer cells to the chemotherapeutic drug oxaliplatin (OXA) by targeting YBX1

The mechanisms underlying oxaliplatin (OXA) resistance in colon cancer cells are not fully understood. MicroRNAs (miRNAs) play important roles in tumorigenesis and drug resistance. However, the relationship between miRNA and OXA resistance in colon cancer cells has not been previously explored. In this study, we utilized microRNA microarray analysis and real-time PCR to verify that miR-93, miR-191, miR-137, miR-181 and miR-491-3p were significantly down-regulated and that miR-96, miR-21, miR-22, miR-15b and miR-92 were up-regulated in both HCT-15/OXA and SW480/OXA cell lines. Blocking miR-137 caused a significant inhibition of OXA-induced cytotoxicity, therefore, miR-137 was chosen for further research. An in vitro cell viability assay showed that knockdown of miR-137 in HCT-15 and SW480 cells caused a marked inhibition of OXA-induced cytotoxicity. Moreover, we found that miR-137 was involved in repression of YBX1 expression through targeting its 3'-untranslated region. Furthermore, down-regulation of miR-137 conferred OXA resistance in parental cells, while over-expression of miR-137 sensitized resistant cells to OXA, which was partly rescued by YBX1 siRNA. The results of this study may aid the development of therapeutic strategies to overcome colon cancer cell resistance to OXA.

Snail-Modulated MicroRNA 493 Forms a Negative Feedback Loop with the Insulin-Like Growth Factor 1 Receptor Pathway and Blocks Tumorigenesis

In this study, we have identified one microRNA, microRNA 493 (miR-493), which could simultaneously and directly regulate multiple genes downstream of the insulin-like growth factor 1 receptor (IGF1R) pathway, including IGF1R, by binding with complementary sequences in the 3' untranslated region (UTR) of mRNAs of IGF1R, insulin receptor substrate 1 (IRS1), and mitogen-activated protein kinase 1 (MAPK1), thereby potentiating their inhibitory function at multiple levels in development and progression of cancers. This binding was further confirmed by pulldown of miR with AGO-2 antibody. Further, results from head and neck samples showed that miR-493 levels were significantly downregulated in tumors, with a concomitant increase in the expression of IGF1R and key downstream effectors. Functional studies from miR-493 overexpression cells and nude-mouse models revealed the tumor suppressor functions of miR-493. Regulation studies revealed that Snail binds to the miR-493 promoter and represses it. We found the existence of a dynamic negative feedback loop in the regulation of IGF1R and miR-493 mediated via Snail. Our study showed that nicotine treatment significantly decreases the levels of miR-493-with a concomitant increase in the levels of Snail-an indication of progression of cells toward tumorigenesis, reestablishing the role of tobacco as a major risk factor for head and neck cancers and elucidating the mechanism behind nicotine-mediated tumorigenesis.

MiR-375 suppresses invasion and metastasis by direct targeting of SHOX2 in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the most common histological type in China. MicroRNAs are endogenously expressed in mammals and play a significant role in tumor invasion and metastasis by targeting potential downstream genes. In the present study, microarray analysis showed that miR-375 expression was distinctly downregulated in ESCC compared with that in normal esophageal epithelium tissues. Then, luciferase reporter assay showed that SHOX2 was the direct downstream target of miR-375 and this interaction was confirmed by the rescue experiments. Quantitative polymerase chain reaction results also showed that SHOX2 expression was upregulated in ESCC cells and tissues. Further analysis showed that SHOX2 induced proliferation, invasion, and metastasis of ESCC both in vivo and in vitro. Moreover, the interaction between miR-375 and SHOX2 affected the epithelial-to-mesenchymal transition. We conclude that miR-375 may suppress invasion and metastasis of ESCC by directly targeting SHOX2. The miR-375/SHOX2 axis may be a novel therapeutic target for ESCC.