microRNAs in oral cancer: Moving from bench to bed as next generation medicine

Identification of common salivary miRNA in oral lichen planus and oral squamous cell carcinoma: systematic review and meta-analysis

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory condition that can impact patients' quality of life. While its exact etiology remains unclear, it is associated with an increased risk of malignant transformation. Currently, the diagnosis of OLP relies on clinical examination and histopathological analysis, which can be invasive. Therefore, there is an urgent need for non-invasive and accurate diagnostic biomarkers. This systematic review and meta-analysis aims to investigate the potential of salivary microRNAs as promising candidates for OLP diagnosis. This meta-analysis seeks to identify specific microRNAs that are differentially expressed and could serve as reliable biomarkers for OLP diagnosis.

METHODS

Our strategy involved searching for pertinent keywords in multiple academic databases including Cochrane Library, Embase, LIVIVO, MEDLINE, Ovid, ProQuest, Scopus, Web of Science, Espacenet, and Google Scholar search engine. Upon identification, articles were screened and data extracted from the eligible studies. Split component synthesis method was utilized to assess specificity, sensitivity, likelihood and diagnostic odds ratios. The random-effects meta-analysis approach was used to combine study findings and develop pooled diagnostic performance metrics. Hierarchical summary receiver operating characteristic (ROC) plots were generated to determine area under the curve. Subgroup analyses concerning the type of saliva and control groups were also performed.

RESULTS

Among the fourteen studies included in our systematic review, five were eligible for meta-analysis. Salivary microRNAs showed the pooled sensitivity of 0.80 (95% Confidence Interval (95% CI): 0.68-0.88), specificity of 0.89 (95% CI: 0.82-0.94), diagnostic odds ratio of 28.45 (95% CI: 10.40-77.80), and area under the curve (AUC) of 0.93 for OLP diagnosis. Unstimulated saliva had higher sensitivity and specificity than oral swirl samples as the biomarker medium for OLP diagnosis. Meta-analysis uncovered that miR-27a, miR-137, miR-1290, miR-27b, miR-4484, miR-142, and miR-1246 had the highest diagnostic odds ratio for OLP.

CONCLUSIONS

Our systematic review and meta-analysis demonstrate that salivary microRNAs can serve as valuable biomarkers for the diagnosis of OLP. The findings highlight the exceptional accuracy of salivary microRNAs in differentiating OLP patients from healthy controls and assessing the risk of malignant transformation.

Targeted gene therapy for cancer: the impact of microRNA multipotentiality

Cancer is a life-threatening disease and its management is difficult due to its complex nature. Cancer is characterized by genomic instability and tumor-associated inflammation of the supporting stoma. With the advances in omics science, a treatment strategy for cancer has emerged, which is based on targeting cancer-driving molecules, known as targeted therapy. Gene therapy, a form of targeted therapy, is the introduction of nucleic acids into living cells to replace a defective gene, promote or repress gene expression to treat a disease. MicroRNAs (miRNAs) are non-coding RNAs (ncRNAs) that regulate gene expression and thus are involved in physiological processes like cell proliferation, differentiation, and cell death. miRNAs control the actions of many genes. They are deregulated in cancer and their abnormal expression influences genetic and epigenetic alterations inducing carcinogenesis. In this review, we will explain the role of miRNAs in normal and abnormal gene expression and their usefulness in monitoring cancer patients. Besides, we will discuss miRNA-based therapy as a method of gene therapy and its impact on the success of cancer management.

Identification of Stage-Specific microRNAs that Govern the Early Stages of Sequential Oral Oncogenesis by Strategically Bridging Human Genetics with Epigenetics and Utilizing an Animal Model

Oral squamous cell carcinoma (OSCC) is a highly prevalent and aggressive malignancy, with mortality rates reaching 60%, mainly due to its excessive diagnostic delay. MiRNAs, a class of crucial epigenetic gene-expression regulators, have emerged as potential diagnostic biomarkers, with >200 molecules exhibiting expressional dysregulation in OSCC. We had previously established an in silico methodology for the identification of the most disease-specific molecules by bridging genetics and epigenetics. Here, we identified the stage-specific miRNAs that govern the asymptomatic early stages of oral tumorigenesis by exploiting seed-matching and the reverse interplay between miRNA levels and their target genes' expression. Incorporating gene-expression data from our group's experimental hamster model of sequential oral oncogenesis, we bioinformatically detected the miRNAs that simultaneously target/regulate >75% of the genes that are characteristically upregulated or downregulated in the consecutive stages of hyperplasia, dysplasia, and early invasion, while exhibiting the opposite expressional dysregulation in OSCC-derived tissue and/or saliva specimens. We found that all stages share the downregulation of miR-34a-5p, miR124-3p, and miR-125b-5p, while miR-1-3p is under-expressed in dysplasia and early invasion. The malignant early-invasion stage is distinguished by the downregulation of miR-147a and the overexpression of miR-155-5p, miR-423-3p, and miR-34a-5p. The identification of stage-specific miRNAs may facilitate their utilization as biomarkers for presymptomatic OSCC diagnosis.

A study of microRNAs as new prognostic biomarkers in anal cancer patients

BACKGROUND

MicroRNA (MiR) influences the growth of cancer by regulation of mRNA for 50-60% of all genes. We present as per our knowledge the first global analysis of microRNA expression in anal cancer patients and their prognostic impact.

METHODS

Twenty-nine patients with T1-4 N0-3 M0 anal cancer treated with curative intent from September 2003 to April 2011 were included in the study. RNA was extracted from fresh frozen tissue and sequenced using NGS. Differentially expressed microRNAs were identified using the R-package DEseq2 and the endpoints were time to progression (TTP) and cancer specific survival (CSS).

RESULTS

Five microRNAs were significantly associated with 5-year progression free survival (PFS): Low expression of two microRNAs was associated with higher PFS, miR-1246 (100% vs. 55.6%, p = 0.008), and miR-135b-5p (92.9% vs. 59.3%, p = 0.041). On the other hand, high expressions of three microRNAs were associated with higher PFS, miR-148a-3p (93.3% vs. 53.6%, p = 0.025), miR-99a-5p (92.9% vs. 57.1%, p = 0.016), and let-7c-3p (92.9% vs. 57.1%, p = 0.016). Corresponding findings were documented for CSS.

INTERPRETATION

Our study identified five microRNAs as prognostic markers in anal cancer. MiR-1246 and microRNA-135b-5p were oncoMiRs (miRs with oncogene effects), while miR-148a-3p, miR- 99a-5p, and let-7c-3p acted as tumour suppressors in anal cancer patients.

Clinical value and potential circulating of miR-99a as tumor suppressor biomarker in serum of oral squamous cell carcinoma and erosive atrophic lichen planus

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is the most common type of oral neoplasms that consist of more over 90% of oral cancers. It was demonstrated that erosive atrophic oral lichen planus (OLP) has potential of malignancy transformation into OSCC. The microRNAs are non-coding regulator sequences involved in cancer process. The miR-99a involve in growth, proliferation, migration, invasion, and metastasis of tumor cells. Therefore, we evaluated miR-99a expression in serum of OSCC and erosive atrophic OLP patients in comparison to healthy control individuals to more investigate about level of miR-99a expression in potential premalignant disorder (erosive atrophic OLP) in comparison to malignant transformation form (OSCC). Gene ontology (GO) and pathway analyses were performed to better understand the importance of miR-99a in OSCC.

MATERIALS AND METHODS

In this cross-sectional study, total 90 serum samples from OSCC patients (n = 30), erosive atrophic OLP (n = 30) and healthy control individuals (n = 30) were collected, and then evaluated for miR-99a expression by qPCR. Pathway analysis and protein-protein interaction were done using STRING (v: 12.0), and (GO) terms and related genes were extracted from the GO online search tool. The statistical analysis was evaluated by Kruskal Wallis, Chi-Square, Kruskal Wallis, Spearman and Mann-Whitney tests. The p-value less than 0.05 was considered statistically significant.

RESULTS

miR-99a expression down regulated in OSCC in comparison to erosive atrophic OLP and control groups (p < 0.05). The miR-99a up regulated in grade I more than grades II and III (p < 0.05). We showed upregulation of miR-99a in early stage more than advanced stage (p < 0.05). Expression of miR-99a reduced accordance to the increasing of tumor size and lymph involvement levels (p < 0.05). The 165 determined targets were classified into three domains. The most significant enrichment in biological processes, cellular components, and molecular functions was in the cellular nitrogen compound biosynthetic process, cytosolic ribosome, and protein binding, respectively.

CONCLUSIONS

We highlighted tumor suppressive role of miR-99a in OSCC patients. It seems that miR-99a can be considered a valuable biomarker for the early diagnosis of erosive atrophic OLP before transformation.

CLINICAL RELEVANCE

Our results may help to better understand the prognostic factor for oral squamous cell carcinoma to evaluate survival and subsequent tumor development. And it may also help to understand the pathogenesis of OSCC.

Intronic miR-6741-3p targets the oncogene SRSF3: Implications for oral squamous cell carcinoma pathogenesis

Epigenetic silencing through methylation is one of the major mechanisms for downregulation of tumor suppressor miRNAs in various malignancies. The aim of this study was to identify novel tumor suppressor miRNAs which are silenced by DNA hypermethylation and investigate the role of at least one of these in oral squamous cell carcinoma (OSCC) pathogenesis. We treated cells from an OSCC cell line SCC131 with 5-Azacytidine, a DNA methyltransferase inhibitor, to reactivate tumor suppressor miRNA genes silenced/downregulated due to DNA methylation. At 5-day post-treatment, total RNA was isolated from the 5-Azacytidine and vehicle control-treated cells. The expression of 2,459 mature miRNAs was analysed between 5-Azacytidine and control-treated OSCC cells by the microRNA microarray analysis. Of the 50 miRNAs which were found to be upregulated following 5-Azacytidine treatment, we decided to work with miR-6741-3p in details for further analysis, as it showed a mean fold expression of >4.0. The results of qRT-PCR, Western blotting, and dual-luciferase reporter assay indicated that miR-6741-3p directly targets the oncogene SRSF3 at the translational level only. The tumor-suppressive role of miR-6741-3p was established by various in vitro assays and in vivo study in NU/J athymic nude mice. Our results revealed that miR-6741-3p plays a tumor-suppressive role in OSCC pathogenesis, in part, by directly regulating SRSF3. Based on our observations, we propose that miR-6741-3p may serve as a potential biological target in tumor diagnostics, prognostic evaluation, and treatment of OSCC and perhaps other malignancies.

Evaluation of salivary transferrin in patients with oral squamous cell carcinoma

OBJECTIVES

About 94% of oral cancers are squamous cell carcinomas (OSCCs). Its occurrence is age-related due to some factors. Salivary biomarkers have good susceptibility to OSCC's early diagnosis. Moreover, since the clinical diagnosis of advanced stages of OSCC is feasible, its prognosis is very poor.

MATERIAL AND METHODS

According to inclusion and exclusion criteria, 40 OSCC patients and 40 healthy people were selected, and 5 mL of saliva were prepared from each person. The quantity of saline transferrin was computed. After that, the data were analyzed.

RESULTS

Our study results demonstrated that the mean and standard deviation of the salivary transferrin in the control group were 1.234 mL and 0.374, respectively, and in the case group, it was equal to 2.512 mL for the mean and 0.463 for the standard deviation. There was a statistically substantial difference between the mean of the salivary transferrin variable in the two study groups.

CONCLUSION

In conclusion, the mean concentration of salivary transferrin in the case group was higher than in the control group.

Identification of CT-based non-invasive radiomic biomarkers for overall survival prediction in oral cavity squamous cell carcinoma

This study addresses the limited non-invasive tools for Oral Cavity Squamous Cell Carcinoma (OSCC) survival prediction by identifying Computed Tomography (CT)-based biomarkers to improve prognosis prediction. A retrospective analysis was conducted on data from 149 OSCC patients, including CT radiomics and clinical information. An ensemble approach involving correlation analysis, score screening, and the Sparse-L1 algorithm was used to select functional features, which were then used to build Cox Proportional Hazards models (CPH). Our CPH achieved a 0.70 concordance index in testing. The model identified two CT-based radiomics features, Gradient-Neighboring-Gray-Tone-Difference-Matrix-Strength (GNS) and normalized-Wavelet-LLL-Gray-Level-Dependence-Matrix-Large-Dependence-High-Gray-Level-Emphasis (HLE), as well as stage and alcohol usage, as survival biomarkers. The GNS group with values above 14 showed a hazard ratio of 0.12 and a 3-year survival rate of about 90%. Conversely, the GNS group with values less than or equal to 14 had a 49% survival rate. For normalized HLE, the high-end group (HLE > - 0.415) had a hazard ratio of 2.41, resulting in a 3-year survival rate of 70%, while the low-end group (HLE ≤ - 0.415) had a 36% survival rate. These findings contribute to our knowledge of how radiomics can be used to predict the outcome so that treatment plans can be tailored for patients people with OSCC to improve their survival.

Identification of CT-based non-invasive Radiographic Biomarkers for Overall Survival Stratification in Oral Cavity Squamous Cell Carcinoma

This study addresses the limited non-invasive tools for Oral Cavity Squamous Cell Carcinoma OSCC survival prediction by identifying Computed Tomography (CT)-based biomarkers for improved prognosis. A retrospective analysis was conducted on data from 149 OSCC patients, including radiomics and clinical. An ensemble approach involving correlation analysis, score screening, and the Sparse-L1 algorithm was used to select functional features, which were then used to build Cox Proportional Hazards models (CPH). Our CPH achieved a 0.70 concordance index in testing. The model identified two CT-based radiomics features, Gradient-Neighboring-Gray-Tone-Difference-Matrix-Strength (GNS) and normalized-Wavelet-LLL-Gray-Level-Dependence-Matrix-Large-Dependence-High-Gray-Level-Emphasis (HLE), as well as smoking and alcohol usage, as survival biomarkers. The GNS group with values above 14 showed a hazard ratio of 0.12 and a 3-year survival rate of about 90%. Conversely, the GNS group with values less than or equal to 14 had a 49% survival rate. For normalized HLE, the high-end group (HLE > -0.415) had a hazard ratio of 2.41, resulting in a 3-year survival rate of 70%, while the low-end group (HLE <= -0.415) had a 36% survival rate. These findings contribute to our knowledge of how radiomics can be used to anticipate the outcome and tailor treatment plans from people with OSCC.

Review of Disease-Specific microRNAs by Strategically Bridging Genetics and Epigenetics in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most prevalent human malignancies and a global health concern with a poor prognosis despite some therapeutic advances, highlighting the need for a better understanding of its molecular etiology. The genomic landscape of OSCC is well-established and recent research has focused on miRNAs, which regulate gene expression and may be useful non-invasive biomarkers or therapeutic targets. A plethora of findings regarding miRNA expression have been generated, posing challenges for the interpretation and identification of disease-specific molecules. Hence, we opted to identify the most important regulatory miRNAs by bridging genetics and epigenetics, focusing on the key genes implicated in OSCC development. Based on published reports, we have developed custom panels of fifteen major oncogenes and five major tumor suppressor genes. Following a miRNA/target gene interaction analysis and a comprehensive study of the literature, we selected the miRNA molecules which target the majority of these panels that have been reported to be downregulated or upregulated in OSCC, respectively. As a result, miR-34a-5p, miR-155-5p, miR-124-3p, miR-1-3p, and miR-16-5p appeared to be the most OSCC-specific. Their expression patterns, verified targets, and the signaling pathways affected by their dysregulation in OSCC are thoroughly discussed.

Microneedles: structure, classification, and application in oral cancer theranostics

Oral cancer is a malignant tumor that threatens the health of individuals on a global scale. Currently available clinical treatment methods, including surgery, radiotherapy, and chemotherapy, significantly impact the quality of life of patients with systemic side effects. In the treatment of oral cancer, local and efficient delivery of antineoplastic drugs or other substances (like photosensitizers) to improve the therapy effect is a potential way to optimize oral cancer treatments. As an emerging drug delivery system in recent years, microneedles (MNs) can be used for local drug delivery, offering the advantages of high efficiency, convenience, and noninvasiveness. This review briefly introduces the structures and characteristics of various types of MNs and summarizes MN preparation methods. An overview of the current research application of MNs in different cancer treatments is provided. Overall, MNs, as a means of transporting substances, demonstrate great potential in oral cancer treatments, and their promising future applications and perspectives of MNs are outlined in this review.

MiR-144/451a cluster synergistically modulates growth and metastasis of Oral Carcinoma

OBJECTIVES

MicroRNA (miRNA) clusters co-transcribe and function in a coordinated fashion mediating synergistic or antagonistic regulatory effects. MiR-144 and miR-451a are deregulated in various cancers but the combined regulatory role of miR-144/451a cluster in oral squamous cell carcinoma (OSCC) remains unexplored. In the present study, we studied the synergistic effect of miR-144/451a cluster on oral cancer progression.

MATERIALS AND METHODS

miR-144 and miR-451a expression was explored in OSCC cell lines by quantitative real-time PCR (qRT-PCR). Proliferation, wound healing, migration and invasion, spheroid formation, and colony formation assays were performed after transfection with miR-144-3p, miR-451a, miR-144-5p, and co-expressed miR-144/451a. Expression of putative target genes was analyzed using qRT-PCR and Western blotting.

RESULTS

miR-144 and miR-451a were downregulated in all cell lines. The cell viability and stemness of cancer cell lines were unaltered when treated with miRNA mimics. However, co-expressed miR-144/451a significantly reduced the migratory, invasive, and clonogenic potential of cells than individual miRNAs.

CONCLUSION

miR-144/451a cluster functions as a tumor suppressor in OSCC by inhibiting cancer cell invasion, migration, and clonogenic potential.

The paradigm of miRNA and siRNA influence in Oral-biome

Short nucleotide sequences like miRNA and siRNA have attracted a lot of interest in Oral-biome investigations. miRNA is a small class of non-coding RNA that regulates gene expression to provide effective regulation of post-transcription. On contrary, siRNA is 21-25 nucleotide dsRNA impairing gene function post-transcriptionally through inhibition of mRNA for homologous dependent gene silencing. This review highlights the application of miRNA in oral biome including oral cancer, dental implants, periodontal diseases, gingival fibroblasts, oral submucous fibrosis, radiation-induced oral mucositis, dental Pulp, and oral lichenoid disease. Moreover, we have also discussed the application of siRNA against the aforementioned disease along with the impact of miRNA and siRNA to the various pathways and molecular effectors pertaining to the dental diseases. The influence of upregulation and downregulation of molecular effector post-treatment with miRNA and siRNA and their impact on the clinical setting has been elucidated. Thus, the mentioned details on application of miRNA and siRNA will provide a novel gateway to the scholars to not only mitigate the long-lasting issue in dentistry but also develop new theragnostic approaches.

A novel panel of clinically relevant miRNAs signature accurately differentiates oral cancer from normal mucosa

INTRODUCTION

Although a considerable body of knowledge has been accumulated regarding the early diagnosis and treatment of oral squamous cell carcinoma (OSCC), its survival rates have not improved over the last decades. Thus, deciphering the molecular mechanisms governing oral cancer will support the development of even better diagnostic and therapeutic strategies. Previous studies have linked aberrantly expressed microRNAs (miRNAs) with the development of OSCC.

METHODS

We combined bioinformatical and molecular methods to identify miRNAs with possible clinical significance as biomarkers in OSCC. A set of 10 miRNAs were selected via an in silico approach by analysing the 3'untranslated regions (3'UTRs) of cancer-related mRNAs such as FLRT2, NTRK3, and SLC8A1, TFCP2L1 and etc. RT-qPCR was used to compare the expression of in silico identified miRNAs in OSCC and normal tissues (n=32).

RESULTS

Among the screened miRNAs, miR-21-5p (p < 0.0001), miR-93-5p (p < 0.0197), miR-146b-5p (p <0.0012), miR-155-5p (p < 0.0001), miR-182-5p (p < 0.0001) were significantly overexpressed, whereas miR-133b (p < 0.05) was significantly downregulated in OSCC tissues, a scenario confirmed in two additional OSCC validation cohorts: Regina Elena National Cancer Institute (IRE cohort, N=74) and The Cancer Genome Atlas Data Portal (TCGA cohort, N=354). Initial stage tumors (T1, T2) expressed significantly higher levels of miR-133b (p < 0.0004) compared to more advanced ones (T3, T4). Also, we identified miR-93-5p (p < 0.0003), miR-133b (p < 0.0017) and miR-155-5p (p < 0.0004) as correlated with HPV-induced OSCC. The high expression of these 6 miRNAs as a signature predicted shorter disease-free survival (DFS) and could efficiently distinguish OSCC cases from healthy controls with areas under the curve (AUC) of 0.91 with sensitivity and specificity of 0.98 and 0.6, respectively. Further target identification analysis revealed enrichment of genes involved in FOXO, longevity, glycan biosynthesis and p53 cancer-related signaling pathways. Also, the selected targets were underexpressed in OSCC tissues and showed clinical significance related to overall survival (OS) and DFS.

DISCUSSION

Our results demonstrate that a novel panel consisting of miR-21-5p, miR-93-5p, miR-133b, miR-146b-5p, miR-155-5p and miR-182-5p could be used as OSCC-specific molecular signature with diagnostic and prognostic significance related to OS and DFS.

Younus P, Venugopal A, Suresh Babu HW, Ajay E, Sanjana M, Arul N, Balachandar V. A new insight into the diverse facets of microRNA-31 in oral squamous cell carcinoma

Background

Micro-RNAs (miRNAs) have been reported as an emerging biomarker in many cancer types. They are used as diagnostic and prognostic biomarkers and could be considered therapeutic targets in treating the same.

Main body

Studies have proven that miRNAs play an essential role in molecular cancer pathophysiology, including oral squamous cell carcinoma. Distinct expression profiles of different miRNAs have been demonstrated in oral squamous cell carcinoma. Among the miRNAs, the miR-31 has strong potential as a unique biomarker in head and neck squamous cell carcinoma, and the increased expression was correlated to a poor clinical outcome with a likely contribution to oral carcinogenesis.

Short conclusion

The recent research on different aspects of miR-31 as a biomarker and also its potential application in the development of therapy for oral squamous cell carcinoma has been focused in this review.

Graphical abstract

Identification of Potential miRNA-mRNA Regulatory Network in the Development of Oral Cancer

Background

Oral cancer is a difficult question in modern medical system, and there are few effective strategies to completely heal these diseases. This research investigated the miRNA-mRNA network in oral cancer development via bioinformatics excavation.

Methods

GSE28100 and GSE23558 in the GEO database were selected for bioinformatics analysis. The datasets were analyzed with GEO2R to obtain the related matrix files. The hot plot and heatmap of the matrix files were drawn with R language. The MiRDIP database was applied to predict and screen the targets of miRNAs. The DEGs in the matrix files were analyzed with the DAVID database and visualized with R language for enrichment analysis. The PPI-network of the DEGs was established with the STRING database and Cytoscape. Besides, the miRNA-mRNA was visualized by Cytoscape.

Results

35 genes were identified as the DEGs in GES28100. 1651 genes were identified as the DEGs in GSE23558. 143 common genes in the targets of miRNAs in GSE28100 and the DEGs in GSE the targets of DEGs in GES28100 and common genes were enriched in the PI3K/AKT pathway, MAPK pathway, etc. The DEGs in GSE28100 and GSE23558 were involved in the regulations of transcription from RNA polymerase II promoter and DNA transcription. The DEGs in GSE28100 and GSE23558 were established with the miRNA-mRNA network.

Conclusion

This research identified miR-15b-5p, miR-199a-3p, miR-21-5p, miR-424-5p, and miR-454-3p as the biomarker of oral cancer and established the miRNA-mRNA network in oral progression.

Promising Biomarkers in Head and Neck Cancer: The Most Clinically Important miRNAs

Head and neck cancers (HNCs) comprise a heterogeneous group of tumors that extend from the oral cavity to the upper gastrointestinal tract. The principal etiologic factors for oral tumors include tobacco smoking and alcohol consumption, while human papillomavirus (HPV) infections have been accused of a high incidence of pharyngeal tumors. Accordingly, HPV detection has been extensively used to categorize carcinomas of the head and neck. The diverse nature of HNC highlights the necessity for novel, sensitive, and precise biomarkers for the prompt diagnosis of the disease, its successful monitoring, and the timely prognosis of patient clinical outcomes. In this context, the identification of certain microRNAs (miRNAs) and/or the detection of alterations in their expression patterns, in a variety of somatic fluids and tissues, could serve as valuable biomarkers for precision oncology. In the present review, we summarize some of the most frequently studied miRNAs (including miR-21, -375, -99, -34a, -200, -31, -125a/b, -196a/b, -9, -181a, -155, -146a, -23a, -16, -29, and let-7), their role as biomarkers, and their implication in HNC pathogenesis. Moreover, we designate the potential of given miRNAs and miRNA signatures as novel diagnostic and prognostic tools for successful patient stratification. Finally, we discuss the currently ongoing clinical trials that aim to identify the diagnostic, prognostic, or therapeutic utility of miRNAs in HNC.

The Prognostic Role of miR-31 in Head and Neck Squamous Cell Carcinoma: Systematic Review and Meta-Analysis with Trial Sequential Analysis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with high recurrence, metastasis, and poor treatment outcome. Prognostic survival biomarkers can be a valid tool for assessing a patient's life expectancy and directing therapy toward specific targets. Recent studies have reported microRNA (miR) might play a critical role in regulating different types of cancer. The main miR used as a diagnostic and prognostic biomarker and reported in the scientific literature for HNSCC is miR-21. Other miRs have been investigated to a lesser extent (miR-99a, miR-99b, miR-100, miR-143, miR-155, miR-7, miR-424, miR-183), but among these, the one that has attracted major interest is the miR-31.

METHODS

The systematic review was conducted following the PRISMA guidelines using electronic databases, such as PubMed, Scopus, and the Cochrane Central Register of Controlled Trials, with the use of combinations of keywords, such as miR-31 AND HNSCC, microRNA AND HNSCC, and miR-31. The meta-analysis was performed using the RevMan 5.41 software (Cochrane Collaboration, Copenhagen, Denmark).

RESULTS

This search produced 721 records, which, after the elimination of duplicates and the application of the inclusion and exclusion criteria, led to 4 articles. The meta-analysis was conducted by applying fixed-effects models, given the low rate of heterogeneity (I2 = 40%). The results of the meta-analysis report an aggregate hazard ratio (HR) for the overall survival (OS), between the highest and lowest miR-31 expression, of 1.59, with the relative intervals of confidence (1.22 2.07). Heterogeneity was evaluated through Chi2 = 5.04 df = 3 (p = 0.17) and the Higgins index I2 = 40; testing for the overall effect was Z = 3.44 (p = 0.00006). The forest plot shows us a worsening HR value of OS, in relation to the elevated expression of miR-31.

CONCLUSIONS

In conclusion, the data resulting from the current meta-analysis suggest that miR-31 is associated with the prognosis of patients with HNSCC and that elevated miR-31 expression could predict a poor prognosis in patients with this type of neoplasm.

Identification of key miRNAs and targeted genes involved in the progression of oral squamous cell carcinoma

Background/purpose

Oral squamous cell carcinoma (OSCC) is one of the most common types of head and neck squamous cell carcinoma. Accurate biomarkers are needed for early diagnosis and prognosis of OSCC. MicroRNAs (miRNAs) have shown great values in different types of cancers including OSCC. However, most of the miRNAs involved in the development of OSCC remain uncovered. This study aimed to identify hub miRNAs and mRNAs in OSCC.

Materials and methods

We explored the roles of key miRNAs, target genes and their relationships in OSCC using an integrated bioinformatics approach. Initially, Two OSCC microarray datasets from the Gene Expression Omnibus database were obtained to analyze miRNA expression. MiRNA-targeted mRNAs were acquired, and gene ontology/kyoto encyclopedia of genes and genomes analyses were performed. Thereafter, we constructed a protein–protein interaction (PPI) network to identify hub genes and a miRNA-mRNA interaction network was used to identify key miRNAs. Furthermore, differential gene expression and Kaplan–Meier Plotter survival analysis was performed to evaluate their potential clinical application values.

Results

Four upregulated, two downregulated miRNAs and 608 target genes of the differentially expressed miRNAs were identified. The PPI and miRNA-mRNA interaction networks highlighted 10 hub genes and two key miRNAs, and pathway analyses showed their correlative involvement in tumorigenesis-related processes. Of these miRNAs and genes, miR-125b, β-actin, vinculin and histone deacetylase 1 were correlated with overall survival (P < 0.05).

Conclusion

These findings indicate that miR-21 and miR-125b, associated with the 10 hub genes, jointly participate in OSCC tumorigenesis, offering insight into the molecular mechanisms underlying OSCC as potential targets for early diagnosis, treatment and prognosis.

Network Pharmacology Identifies Therapeutic Targets and the Mechanisms of Glutathione Action in Ferroptosis Occurring in Oral Cancer

Oral cancer (OC) is one of the most pernicious cancers with increasing incidence and mortality worldwide. Surgery is the primary approach for the treatment of early-stage OC, which reduces the quality of life of the patients. Therefore, there is an urgent need to discover novel treatments for OC. Targeting ferroptosis to induce cell death through the modulation of lipid oxidation has been used as a new approach to treat many cancers. Glutathione (GSH) is a coenzyme factor of GSH peroxidase 4, and it carries potential applicability in treating OC. By using network pharmacology and molecular docking followed by systematic bioinformatic analysis, we aimed to study GSH-targeting ferroptosis to treat OC. We identified 14 core molecular targets, namely, EGFR, PTGS2, HIF1A, VEGFA, TFRC, SLC2A1, CAV1, CDKN2A, SLC3A2, IFNG, NOX4, DDIT4, CA9, and DUSP1, involved in ferroptosis that were targeted by GSH for OC treatment. Functional characterization of these molecular targets showed their importance in the control of cell apoptosis, cell proliferation, and immune responses through various kinase activities such as the mitogen-activated protein kinase activity (e.g., ERK1 and ERK2 cascades) and modulation of TOR signaling (e.g., the HIF-1 signaling pathway). Molecular docking further revealed the direct binding of GSH with EGFR, PTGS2, and HIF1A proteins. These findings provide a novel insight into the targets of GSH in ferroptosis as well as possible molecular mechanisms involved, suggesting the possible use of GSH as a combined therapy for treating OC.

MicroRNA31 and MMP-1 contribute to the differentiated pathway of invasion -with enhanced epithelial-to-mesenchymal transition- in squamous cell carcinoma of the skin

Epithelial to mesenchymal transition (EMT) is an important mechanism of invasion in cutaneous squamous cell carcinomas (cSCCs) and has been found to be enhanced in tumors originated from actinic keratosis with transformation limited to the basal epithelial layer -differentiated pathway-, compared to cases with invasion subsequent to complete epidermal transformation -classical pathway-. Several microRNAs and proteins can contribute to EMT modulation in cSCCs. MicroRNA21 and microRNA31 are involved in posttranscriptional regulation of protein expression and could play a relevant role in EMT and cSCC progression. Throughout the EMT process upregulation of matrix metalloproteinases (MMPs) enhances invasiveness and MMP-1 and MMP-3 contribute to local invasion, angiogenesis and metastasis in cSCCs. Additionally, cSCC development is associated with PTEN loss and NF-κB, NOTCH-1 and p63 activation. The aim of this work is to identify differences in the expression of those molecules between both pathways of cSCCs development. Eight tissue microarrays from 80 consecutive cSCCs were analyzed using LNA-based miRNA in situ hybridization for miRNA21 and miRNA31 evaluation, and immunohistochemistry for MMP-1, MMP-3, PTEN, NOTCH-1, NF-κB, p63 and CD31. Significantly higher expression of miRNA31 (p < 0.0001) and MMP-1 (p = 0.0072) and angiogenesis (p = 0.0199) were found in the differentiated pathway, whereas PTEN loss (p = 0.0430) was more marked in the classical pathway. No significant differences were found for the other markers. Our findings support a contribution of miRNA31 and MMP-1 in the differentiated pathway, associated to EMT and increased microvascularization. The greater PTEN loss in the classical pathway indicate that its relevance in cSCC is not EMT-related.

HPV16 E6 enhances the radiosensitivity in HPV-positive human head and neck squamous cell carcinoma by regulating the miR-27a-3p/SMG1 axis

Background

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common malignant cancer type worldwide. Radiosensitivity has been shown to be significantly increased in patients with human papillomavirus (HPV)-positive HNSCC compared with HPV-negative patients. However, the clinical significance of HPV and its regulatory mechanisms in HNSCC are largely unknown. The aim of our study was to explore the regulatory mechanism of miR-27a-3p in the radiosensitivity of HPV-positive HNSCC cells.

Methods

E6-overexpressing and E6-knockdown HNSCC cell lines were generated and the transfection efficiencies were evaluated by quantitative real-time PCR (RT-qPCR) and western blotting. The expression of miR-27a-3p and DiGeorge syndrome critical region 8 (DGCR8) was examined by RT-qPCR after transfection with E6 overexpressing plasmid or E6 siRNA. The effects of miR-27a-3p on the radiosensitivity of HNSCC cells were explored by a colony formation and TUNEL staining assays. Bioinformatic tools and luciferase reporter assays were used to identify that SMG1 is the direct target of miR-27a-3p. Furthermore, the effect of E6 overexpression on the regulation of the miR-27a-3p/SMG1 axis was investigated.

Results

In our study, we found overexpression of HPV E6 upregulated the expression of DGCR8 and miR-27a-3p in HNSCC cells. We next confirmed that DGCR8 positively regulated the expression of miR-27a-3p in HNSCC cells. The luciferase reporter gene results verified that miR-27a-3p targeted the 3’UTR of SMG1 mRNA. MiR-27a-3p mimics transfection resulted in a decrease in SMG1 expression and miR-27a-3p inhibitor transfection increased SMG1 expression. Apoptotic activity of HNSCC cells was significantly increased in miR-27a-3p mimics HNSCC cells compared with control HNSCC cells. After treatment with 4 Gy irradiation, UM-SCC47 cells transfected with miR-27a-3p inhibitor or SMG1 overexpressing plasmid formed more colonies than the corresponding control cells. Furthermore, the rescue experiments demonstrated that HPV16 E6 improved the radiosensitivity of HNSCC cells by targeting miR-27a-3p/SMG1.

Conclusion

Our study demonstrated that HPV16 E6 activated the DGCR8/miR-27a-3p/SMG1 axis to enhance the radiosensitivity. Our findings might provide a novel therapeutic target to improve the response of HNSCC to radiotherapy.

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.

The Inflammatory Profile of the Tumor Microenvironment, Orchestrated by Cyclooxygenase-2, Promotes Epithelial-Mesenchymal Transition

The tumor microenvironment (TME) corresponds to a complex and dynamic interconnection between the extracellular matrix and malignant cells and their surrounding stroma composed of immune and mesenchymal cells. The TME has constant cellular communication through cytokines that sustain an inflammatory profile, which favors tumor progression, angiogenesis, cell invasion, and metastasis. Although the epithelial-mesenchymal transition (EMT) represents a relevant metastasis-initiating event that promotes an invasive phenotype in malignant epithelial cells, its relationship with the inflammatory profile of the TME is poorly understood. Previous evidence strongly suggests that cyclooxygenase-2 (COX-2) overexpression, a pro-inflammatory enzyme related to chronic unresolved inflammation, is associated with common EMT-signaling pathways. This review article summarizes how COX-2 overexpression, within the context of the TME, orchestrates the EMT process and promotes initial metastatic-related events.

MicroRNAs in oral cancer: Biomarkers with clinical potential

Oral cancer is the sixteenth most common cancer globally, with a relatively poor five-year survival rate of 50%. Thus it is imperative to understand the biology of oral cancer and examine alternative prognostic and therapeutic targets for oral cancer. MicroRNAs (miRNAs) are small non-coding RNAs mediating gene expression at the post-transcriptional level through mRNA degradation or translational repression. miRNAs play an essential role in cancer development and oncogenic cell processes. miRNA deregulation is observed in oral cancer and associated with prognosis. However, the role of miRNAs and their clinical implications in oral cancer is not clear. The current review highlights the miRNA profile of oral cancer and discusses the diagnostic, prognostic and potential therapeutic targets with clinical implications. miRNAs mediate activation or suppression of signalling pathways associated with oral cancer. Hence, a panel of select deregulated miRNAs may indicate clinicopathological features, personalised treatment outcome and provide novel lead profiles of oral cancer. The translational applications of miRNAs may lead to better management and survival of oral cancer patients. The compiled data provides a platform for consideration of miRNA signatures as potential biomarkers for early oral cancer diagnosis, prognosis and as novel molecular therapies.

CircRNAs: A New Chapter in Oral Squamous Cell Carcinoma Biology

With the rapid development of bioinformatics and gene sequencing technologies, understanding of circular RNAs (circRNAs) has been extended, and numerous studies have identified the key regulator role of circRNAs in a variety of diseases, especially in cancer. Recently, accumulated studies of oral squamous cell carcinoma (OSCC) have discovered the great potential of circRNAs, which can serve as prognostic or diagnostic biomarkers and affect the development and therapy of OSCC. In this review, we detail the new progress of circRNA research for OSCC in order to provide new strategies for clinical diagnosis and treatment.