MicroRNA-17/20a functions to inhibit cell migration and can be used a prognostic marker in oral squamous cell carcinoma

Carvacrol inhibits the progression of oral submucous fibrosis via downregulation of PVT1/miR-20a-5p-mediated pyroptosis

Oral submucous fibrosis (OSF) is a precancerous condition in the oral cavity, which is closely related to the myofibroblast conversion of buccal mucosal fibroblasts (BMFs) after chronic consumption of areca nut. Emerging evidence suggests pyroptosis, a form of programmed cell death that is mediated by inflammasome, is implicated in persistent myofibroblast activation and fibrosis. Besides, numerous studies have demonstrated the effects of non-coding RNAs on pyroptosis and myofibroblast activities. Herein, we aimed to target key long non-coding RNA PVT1 with natural compound, carvacrol, to alleviate pyroptosis and myofibroblast activation in OSF. We first identified PVT1 was downregulated in the carvacrol-treated fBMFs and then demonstrated that myofibroblast features and expression of pyroptosis makers were all reduced in response to carvacrol treatment. Subsequently, we analysed the expression of PVT1 and found that PVT1 was aberrantly upregulated in OSF specimens and positively correlated with several fibrosis markers. After revealing the suppressive effects of carvacrol on myofibroblast characterisitcs and pyroptosis were mediated by repression of PVT1, we then explored the potential mechanisms. Our data showed that PVT1 may serve as a sponge of microRNA(miR)-20a to mitigate the myofibroblast activation and pyroptosis. Altogether, these findings indicated that the anti-fibrosis effects of carvacrol merit consideration and may be due to the attenuation of pyroptosis and myofibroblast activation by targeting the PVT1/miR-20a axis.

Dysregulation of exosomal miRNAs and their related genes in head and neck cancer patients

Aim: The present study aimed to figure out the potential role of exosomal microRNAs, and their targeted genes in HNC detection/diagnosis.Methods: In the present study, exosomes were extracted from the serum samples of 400 HNC patients and 400 healthy controls. Exosomes were characterized using TEM, NTA, TEM-immunogold labeling and ELISA. Quantitative PCR was used to measure the expression level of exosomal miRNA-19a, miRNA-19b and targeted genes SMAD2 and SMAD4 in HNC patients and controls.Results: The deregulation of miR-19a (p < 0.01), miR-19b (p < 0.03), SMAD2 (p < 0.04) and SMAD4 (p < 0.04) was observed in HNC patients vs controls.Conclusion: ROC curve and Kaplan-Meier analysis showed the good diagnostic/prognostic value of selected exosomal microRNAs and related genes in HNC patients.

Unraveling the role of miRNAs in the diagnosis, progression, and drug resistance of oral cancer

Oral cancer (OC) is a widely observed neoplasm on a global scale. Over time, there has been an increase in both its fatality and incidence rates. Oral cancer metastasis is a complex process that involves a number of cellular mechanisms, including invasion, migration, proliferation, and escaping from malignant tissue through either lymphatic or vascular channels. MicroRNAs (miRNAs) are a crucial class of short non-coding RNAs recognized as significant modulators of diverse cellular processes and exert a pivotal influence on the carcinogenesis pathway, functioning either as tumor suppressors or as oncogenes. It has been shown that microRNAs (miRNAs) have a role in metastasis at several stages, including epithelial-mesenchymal transition, migration, invasion, and colonization. This regulation is achieved by targeting key genes involved in these pathways by miRNAs. This paper aims to give a contemporary analysis of OC, focusing on its molecular genetics. The current literature and emerging advancements in miRNA dysregulation in OC are thoroughly examined. This project would advance OC diagnosis, prognosis, therapy, and therapeutic implications.

MicroRNAs as Potential Biomarkers of Environmental Exposure to Polycyclic Aromatic Hydrocarbons and Their Link with Inflammation and Lung Cancer

Exposure to atmospheric air pollution containing volatile organic compounds such as polycyclic aromatic hydrocarbons (PAHs) has been shown to be a risk factor in the induction of lung inflammation and the initiation and progression of lung cancer. MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules of ~20-22 nucleotides that regulate different physiological processes, and their altered expression is implicated in various pathophysiological conditions. Recent studies have shown that the regulation of gene expression of miRNAs can be affected in diseases associated with outdoor air pollution, meaning they could also be useful as biomarkers of exposure to environmental pollution. In this article, we review the published evidence on miRNAs in relation to exposure to PAH pollution and discuss the possible mechanisms that may link these compounds with the expression of miRNAs.

MiRNAs that target amyloid precursor protein processing machinery in extracellular vesicles and particles derived from oral squamous cells carcinoma

BACKGROUND

Considering that microRNAs (miRNAs), extracellular vesicles and particles (EVPs) and the amyloid precursor protein (APP) processing have been shown to be altered in oral squamous cells carcinoma (OSCC), it is possible that miRNAs that target APP processing pathways in EVPs are impacted in tumor cells. Our aim was to evaluate miRNAs that target APP itself or disintegrin and metalloproteinase domain 10 (ADAM10), which generate a trophic compound, sAPPα, in EVPs derived from OSCC cell lines, an aggressive and non-invasive, compared to normal keratinocytes.

METHODS

We used two OSCC cell lines, an aggressive human oral squamous cell carcinoma cell line (SCC09) and a less aggressive cell line (CAL27) compared with a keratinocyte lineage (HaCaT). Cells were maintained in cell media, from which we isolated EVPs. EVPs were evaluated regarding their size and concentration using Nanotracking Analysis. We measured the levels of miRNAs which had as potential downstream target APP or ADAM10, specifically miR-20a-5p, miR-103a-3p, miR-424-5p, miR-92b-3p, miR-31-5p, and miR-93-5.

RESULTS

There were no differences on size distributions and concentration of isolated EVPs. OSCC cell lines-derived EVPs miR-20a-5p, miR-92b-3p, and miR-93-5p were upregulated in comparison to HaCaT-derived EVPs; while miR-31-5p was reduced in EVPs obtained from CAL27 cells.

CONCLUSION

Our results indicate changes in miRNAs that target APP machinery processing in EVPs derived from OSCC cell lines of different aggressiveness, which may be involved with abnormal miRNA expression in OSCC tissue and/or releasing tumor suppressor miRNA.

Oral squamous cell carcinomas: state of the field and emerging directions

Oral squamous cell carcinoma (OSCC) develops on the mucosal epithelium of the oral cavity. It accounts for approximately 90% of oral malignancies and impairs appearance, pronunciation, swallowing, and flavor perception. In 2020, 377,713 OSCC cases were reported globally. According to the Global Cancer Observatory (GCO), the incidence of OSCC will rise by approximately 40% by 2040, accompanied by a growth in mortality. Persistent exposure to various risk factors, including tobacco, alcohol, betel quid (BQ), and human papillomavirus (HPV), will lead to the development of oral potentially malignant disorders (OPMDs), which are oral mucosal lesions with an increased risk of developing into OSCC. Complex and multifactorial, the oncogenesis process involves genetic alteration, epigenetic modification, and a dysregulated tumor microenvironment. Although various therapeutic interventions, such as chemotherapy, radiation, immunotherapy, and nanomedicine, have been proposed to prevent or treat OSCC and OPMDs, understanding the mechanism of malignancies will facilitate the identification of therapeutic and prognostic factors, thereby improving the efficacy of treatment for OSCC patients. This review summarizes the mechanisms involved in OSCC. Moreover, the current therapeutic interventions and prognostic methods for OSCC and OPMDs are discussed to facilitate comprehension and provide several prospective outlooks for the fields.

The Potential microRNA Prognostic Signature in HNSCCs: A Systematic Review

Head and neck squamous cell carcinomas (HNSCCs) are often diagnosed at advanced stages, incurring significant high mortality and morbidity. Several microRNAs (miRs) have been identified as pivotal players in the onset and advancement of HNSCCs, operating as either oncogenes or tumor suppressors. Distinctive miR patterns identified in tumor samples, as well as in serum, plasma, or saliva, from patients have significant clinical potential for use in the diagnosis and prognosis of HNSCCs and as potential therapeutic targets. The aim of this study was to identify previous systematic reviews with meta-analysis data and clinical trials that showed the most promising miRs in HNSCCs, enclosing them into a biomolecular signature to test the prognostic value on a cohort of HNSCC patients according to The Cancer Genome Atlas (TCGA). Three electronic databases (PubMed, Scopus, and Science Direct) and one registry (the Cochrane Library) were investigated, and a combination of keywords such as "signature microRNA OR miR" AND "HNSCC OR LSCC OR OSCC OR oral cancer" were searched. In total, 15 systematic literature reviews and 76 prognostic clinical reports were identified for the study design and inclusion process. All survival index data were extracted, and the three miRs (miR-21, miR-155, and miR-375) most investigated and presenting the largest number of patients included in the studies were selected in a molecular biosignature. The difference between high and low tissue expression levels of miR-21, miR-155, and miR-375 for OS had an HR = 1.28, with 95% CI: [0.95, 1.72]. In conclusion, the current evidence suggests that miRNAs have potential prognostic value to serve as screening tools for clinical practice in HNSCC follow-up and treatment. Further large-scale cohort studies focusing on these miRNAs are recommended to verify the clinical utility of these markers individually and/or in combination.

Non-Coding RNAs in Oral Cancer: Emerging Roles and Clinical Applications

Oral cancer (OC) is among the most prevalent cancers in the world. Certain geographical areas are disproportionately affected by OC cases due to the regional differences in dietary habits, tobacco and alcohol consumption. However, conventional therapeutic methods do not yield satisfying treatment outcomes. Thus, there is an urgent need to understand the disease process and to develop diagnostic and therapeutic strategies for OC. In this review, we discuss the role of various types of ncRNAs in OC, and their promising clinical implications as prognostic or diagnostic markers and therapeutic targets. MicroRNA (miRNA), long ncRNA (lncRNA), circular RNA (circRNA), PIWI-interacting RNA (piRNA), and small nucleolar RNA (snoRNA) are the major ncRNA types whose involvement in OC are emerging. Dysregulated expression of ncRNAs, particularly miRNAs, lncRNAs, and circRNAs, are linked with the initiation, progression, as well as therapy resistance of OC via modulation in a series of cellular pathways through epigenetic, transcriptional, post-transcriptional, and translational modifications. Differential expressions of miRNAs and lncRNAs in blood, saliva or extracellular vesicles have indicated potential diagnostic and prognostic importance. In this review, we have summarized all the promising aspects of ncRNAs in the management of OC.

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.

microRNA-17 is a tumor suppressor in oral squamous cell carcinoma and is repressed by LSD1

OBJECTIVE

The effects of epigenetic modifiers have been uncovered on cellular reprogramming and, specifically, on sustaining characteristics of cancer stem cells. We here aim to investigate whether lysine-specific demethylase 1 (LSD1) affects the development of oral squamous cell carcinoma (OSCC) by sustaining the cancer stem cells from OSCC (OSCSCs).

METHODS

RT-qPCR detection was firstly conducted to screen out research gene by determining differential expression of histone demethylases and methylases in identified OSCSCs. Then, microarray analysis was carried out in cells with poor expression of LSD1.

RESULTS

OSCSCs expressed high levels of LSD1, and LSD1 inhibition reduced cell viability, migration, invasion, and sphere formation of OSCSCs. Later mechanistic studies suggested that LSD1 inhibited microRNA (miR)-17 expression through histone demethylation. miR-17 bound to KPNA2, and LSD1 downstream genes were mainly enriched in the PI3K/AKT pathway. Importantly, miR-17 inhibitor reversed the inhibitory effect of si-LSD1 on cell activity, while si-KPNA2 abolished the promotive effect of miR-17 inhibitor on cell activity both in vitro and in vivo.

CONCLUSION

Overall, LSD1 functions as a cancer stem cell supporter in OSCC by catalyzing demethylation of miR-17 and activating the downstream KPNA2/PI3K/AKT pathway, which contributes to understanding of the mechanisms associated with epigenetic regulation in OSCC.

Study of MicroRNA (miR-221-3p, miR-133a-3p, and miR-9-5p) Expressions in Oral Submucous Fibrosis and Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the common types of cancer. Its progression follows a transition from oral potentially malignant disorders (OPMDs) such as oral submucous fibrosis (OSMF). Epigenetic modifiers, especially microRNAs (miRNAs), have an appreciable role in the regulation of various carcinogenic pathways which are being used as biomarkers. miRNAs may also be helpful in the differentiation of oral submucous fibrosis from oral squamous cell carcinoma. Three miRNAs, miR-221-3p, miR133a-3p, and miR-9-5p, were found differentially expressed in many cancers in the literature search supported by our preliminary database search-based screening. The literature and our functional enrichment analysis in an earlier study have reported these miRNAs to regulate carcinogenesis at various steps. In the present study, the expression of these miRNAs was examined in 34 histopathologically confirmed OSCC, 30 OSMF, and 29 control (healthy volunteers) human samples. There was a significant downregulation of miRNA-133a-3p in OSCC compared to OSMF and controls, whereas there was up-regulation in oral submucous fibrosis compared to controls. There was no significant difference in the expression of miR-221-3p between OSCC and OSMF, but an upregulation in OSCC compared to controls. miR-9-5p was also found upregulated in both OSCC and OSMF. Further, miR-133a-3p expression was negatively correlated with age, smoking, drinking status, and AJCC staging, whereas miR-9-5p expression was only positively associated with tobacco/ areca nut chewing. The ROC plots, logistic regression model generated, and the correlation between the expression of miR-9-5p and miR-133a-3p in blood and tissue suggests that these could be used as risk stratification biomarkers.

The miR-17-92 cluster: Yin and Yang in human cancers

MicroRNAs (miRNAs) are non-coding RNAs which modulate gene expression via multiple post-transcriptional mechanisms. They are involved in a variety of biological processes, including cell proliferation, metastasis, metabolism, tumorigenesis, and apoptosis. Dysregulation of miRNA expression has been implicated in human cancers, and they may also serve as biomarkers of disease progression and prognosis. The miR-17-92 cluster is one of the most widely studied miRNA clusters, which was initially reported as an oncogene, but was later reported to exhibit tumour suppressive effects in some human cancers. This review summarizes the recent progress and context-dependant role of this cluster in various cancers. We summarize the known mechanisms which regulate miR-17-92 expression and molecular pathways that are in turn controlled by it. We discuss examples where it acts as an oncogene or a tumour suppressor along with key targets affecting hallmarks of cancer. We discuss how cellular contexts regulate the biological effects of miR-17-92. The plausible mechanisms of its paradoxical roles are explained, and mechanisms are described that may contribute to cell fate regulation by miR-17-92. Further, we discuss recently developed strategies to target miR-17-92 cluster in human cancers. MiR-17-92 may serve as a potential biomarker for prognosis and response to therapy as well as a target for cancer prevention and therapeutics.

MicroRNA-18a regulates the metastatic properties of oral squamous cell carcinoma cells via HIF-1α expression

BACKGROUND

Rapid metastasis of oral squamous cell carcinoma (OSCC) is associated with a poor prognosis and a high mortality rate. However, the molecular mechanisms underlying OSCC metastasis have not been fully elucidated. Although deregulated expression of microRNA (miRNA) has a crucial role in malignant cancer progression, the biological function of miRNA in OSCC progression remains unclear. This study aimed to investigate the function of miRNA-18a in OSCC metastatic regulation via hypoxia-inducible factor 1α (HIF-1α).

METHODS

miRNA-18a-5p (miRNA-18a) expressions in patients with OSCC (n = 39) and in OSCC cell lines (e.g., YD-10B and HSC-2 cells) were analyzed using quantitative real-time polymerase chain reaction. HIF-1α protein expressions in OSCC cells treated with miRNA-18a mimics or combined with cobalt chloride were analyzed using western blotting. The miRNA-18a expression-dependent proliferation and invasion abilities of OSCC cells were analyzed using MTT assay, EdU assay, and a Transwell® insert system.

RESULTS

miRNA-18a expression was significantly lower in OSCC tissue than in the adjacent normal tissue. In OSCC cell lines, HIF-1α expression was significantly decreased by miRNA-18a mimic treatment. Furthermore, the migration and invasion abilities of OSCC cells were significantly decreased by miRNA-18a mimics and significantly increased by the overexpression of HIF-1α under hypoxic conditions relative to those abilities in cells treated only with miRNA-18a mimics.

CONCLUSIONS

miRNA-18a negatively affects HIF-1α expression and inhibits the metastasis of OSCC, thereby suggesting its potential as a therapeutic target for antimetastatic strategies in OSCC.

High expression of miR-17-5p and miR-20a-5p predicts favorable disease-specific survival in stage I-III colon cancer

In many types of cancer, microRNAs (miRs) are aberrantly expressed. The aim of this study was to explore the prognostic impact of miR-17-5p and miR-20a-5p in colon cancer. Tumor tissue from 452 stage I-III colon cancer patients was retrospectively collected and tissue microarrays constructed. miR-17-5p and miR-20a-5p expression was evaluated by in situ hybridization and analyzed using digital pathology. Cell line experiments, using HT-29 and CACO-2, were performed to assess the effect of miR-17-5p and miR-20a-5p over expression on viability, invasion and migration. In multivariate analyses, high miR-17-5p expression in tumor (HR = 0.43, CI 0.26–0.71, p < 0.001) and high expression of miR-20a-5p in tumor (HR = 0.60, CI 0.37–0.97, p = 0.037) and stroma (HR = 0.63, CI 0.42–0.95, p = 0.027) remained independent predictors of improved disease-specific survival. In cell lines, over expression of both miRs resulted in mitigated migration without any significant effect on viability or invasion. In conclusion, in stage I-III colon cancer, high expression of both miR-17-5p and miR-20a-5p are independent predictors of favorable prognosis.

Unraveling diverse roles of noncoding RNAs in various human papillomavirus negative cancers

Human papillomavirus (HPV)-negative tumors distinguish from cancers associated with HPV infection. Due to its high rate of lymph node metastasis and difficulty in inchoate discover and diagnosis, the treatment efficacy of HPV-negative cancers is unsatisfactory. Epidemiological evidence suggests that HPV-negative tumor patients have a poor prognosis, and the mortality is higher than that of cancer patients caused by HPV infection. Evidence has demonstrated that noncoding RNAs (ncRNAs) play a crucial role in regulation of physiological and developmental processes. Therefore, dysregulated ncRNAs are involved in the occurrence of diversified diseases, including cancer. In cumulative studies, ncRNAs are concerned with pathogenetic mechanisms of HPV-negative tumors via regulating gene expression and signal transduction. It is important to decipher the functions of ncRNAs in HPV-negative cancers and identify the potential biomarkers, which will bring new treatment strategies for improving outcome of cancer therapy. In this review, we demonstrated the effects of ncRNAs via regulating the development and progression of HPV- negative tumors by directly or indirectly acting on target molecules, which provide a basis for future tumor targeted therapy by targeting ncRNAs for HPV-negative cancers.

Evaluation of the Expression of miR-486-3p, miR-548-3p, miR-561-5p and miR-509-5p in Tumor Biopsies of Patients with Oral Squamous Cell Carcinoma

Background and objective: Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy. Expression patterns of microRNAs (miRNAs) can direct us in identifying valuable biomarkers for the prognosis of different neoplasms. Inappropriate regulation of miRNAs during physiological procedures can result in malignancies including OSCC. The aim of the present study was to evaluate the expression of miR-486-3p, miR-561-5p, miR-548-3p, and miR-509-5p in tissue biopsy samples with and without OSCC. Materials and methods: This case-control study was conducted on 17 healthy and 17 OSCC tissue biopsy samples. The expression of miRNAs was assessed using quantitative real-time PCR (q-RT-PCR) after RNA extraction from normal and cancer tissues and cDNA synthesis. Results: The means of miRNA-486-3p, miR-561-5p, and miR-548-3p expression were significantly different between OSCC and control groups (p < 0.001), but there was no significant difference in means of miR-509-5p expression between OSCC and control groups (p = 0.179). Conclusions: The findings of this study revealed that the expression of miR-486-3p and miR-561-5p was significantly lower in cancer samples compared to normal tissue samples. On the other hand, miR-548-3p expression increased in the OSCC group compared to the control group.

Exosome-derived microRNAs in oral squamous cell carcinomas impact disease prognosis

OBJECTIVES

microRNA (miRNA) expression patterns have provided new insight as biomarkers of prognosis as well as novel therapeutic targets for several neoplasms. However, the role of exosomal miRNA in the prognosis of oral squamous cell carcinoma (OSCC) has not yet been completely clarified. Paired primary tumor and normal oral epithelial cells from OSCC patients were obtained, and the exosomal miRNA profiles between them were compared by miRNA microarray analysis. The miRNA levels in the serum exosomes of OSCC patients were verified by real-time quantitative reverse transcription PCR (qRT-PCR) analysis. Finally, the biological functions and the potential as a prognostic marker of the selected miRNA candidates were analyzed in the OSCC cells and patients, respectively.

RESULTS

Exosomal miR-155 and miR-21 were significantly upregulated, and exosomal miR-126 was dramatically downregulated in the primary OSCC cells and the serum of OSCC patients. In the analysis of oncogenic behaviors, coculture with either miR-155-rich or miR-21-rich exosomes could promote cell proliferation and invasion accompanied with downregulation of PTEN and Bcl-6 tumor suppressors. Moreover, treatment with miR-126-rich exosomes inhibited oncogenic behaviors and oncogene EGFL7 expression in OSCC cells. Finally, exosomal miR-126 was reduced in the serum of the late-staged OSCC patients, and downregulation of blood exosomal miR-126 was associated with poor survival in OSCC patients.

CONCLUSION

Exosomal miR-155 and miR-21 are oncogenic miRNAs which suppress PTEN and Bcl-6 expression, and exosomal miR-126 acts as a tumor suppressor which downregulates EGFL7 in OSCC. Furthermore, blood exosomal miRNAs may serve as biomarkers for the diagnosis and prognosis of OSCC.

Differential Molecular Expression Patterns Associated with Metastasis in Cutaneous Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

The majority of cutaneous squamous cell carcinomas are treated by surgical removal; however, approximately 4% of tumors will metastasize. Molecular expression testing may improve accuracy in estimating the prognosis and defining the mechanisms important in the disease progression, which may impact response to therapy. Using PubMed (MEDLINE) and EMBASE, a systematic review was performed to evaluate studies published from January 2005 to August 2019 reporting tumor protein or RNA expression along with either outcomes (metastasis or death) or a comparison of primary with metastatic tumor samples. Inclusion criteria were met by 45 studies containing 81 comparisons of 44 distinct proteins and 25 microRNAs. On meta-analysis of studies analyzing primary tumor samples in terms of later outcomes, high primary tumor expression of PD-L1 (OR = 2.34, 95% confidence interval = 1.09-5.02, P = 0.030), EGFR (OR = 2.57, 95% confidence interval = 1.24-5.33, P = 0.011), and podoplanin (OR = 2.33, 95% confidence interval = 1.00-5.41, P = 0.049) conferred increased odds for metastasis. In comparison, metastatic tissue was more likely to have a high expression of PD-L1 than primary tissue (OR = 3.13, 95% confidence interval = 1.00-9.75, P = 0.049). Further studies are needed to confirm whether testing for PD-L1, EGFR, and podoplanin expression aids in cutaneous squamous cell carcinomas prognostic estimation of metastasis or death or predicts response to therapy.

Bioinformatics analysis of dysregulated exosomal microRNAs derived from oral squamous cell carcinoma cells

PURPOSE

The present study aimed to identify dysregulated exosomal miRNAs associated with diagnostic and therapeutic biomarkers in oral squamous cell carcinoma (OSCC).

METHODS

Microarray analysis was used to compare expression profiles of exosomal miRNAs in the OSCC-derived cell lines HSC-2, HSC-3, Ca9-22, and HO-1-N1 with those in human normal keratinocytes (HNOKs). The identified OSCC-related miRNAs and their potential target genes were analyzed with bioinformatic analyses, and the data were subjected to Ingenuity Pathway Analysis (IPA) to clarify functional networks and gene ontologies of the identified exosomal miRNAs secreted by OSCC cells.

RESULTS

Comparison with HNOKs detected 8 upregulated and 12 downregulated miRNAs in OSCC-secreted exosomes. The potential target mRNAs of these dysregulated miRNAs were suggested by IPA, and 6 significant genetic networks were indicated by genetic network analysis. Furthermore, 4 crucial upstream miRNAs-miR-125b-5p, miR-17-5p, miR-200b-3p, and miR-23a-3p-were identified. miR-125b-5p was a central node in the most significant network. Gene ontology analysis showed significant enrichment of genes with cancer-related functions, such as molecular mechanisms of cancer, cell cycle, and regulation of the epithelial-mesenchymal transition.

CONCLUSION

These results provide a comprehensive view of the functions of dysregulated exosomal miRNAs in OSCC, thus illuminating OSCC tumorigenesis and development.

MicroRNAs as Modulators of Oral Tumorigenesis-A Focused Review

Oral cancers constitute the majority of head and neck tumors, with a relatively high incidence and poor survival rate in developing countries. While the five-year survival rates of the oral cancer patients have increased to 65%, the overall survival for advanced stages has been at 27% for the past ten years, emphasizing the necessity for further understanding the etiology of the disease, diagnosis, and formulating possible novel treatment regimens. MicroRNAs (miRNAs), a family of small non-coding RNA, have emerged as master modulators of gene expression in various cellular and biological process. Aberrant expression of these dynamic molecules has been associated with many human diseases, including oral cancers. The deregulated miRNAs have been shown to control various oncogenic processes, including sustaining proliferative signaling, evading growth suppressors, resisting cell death activating invasion and metastasis, and inducing angiogenesis. Hence, the aberrant expression of miRNAs associated with oral cancers, makes them potential candidates for the investigation of functional markers, which will aid in the differential diagnosis, prognosis, and development of novel therapeutic regimens. This review presents a holistic insight into our understanding of the role of miRNAs in regulating various hallmarks of oral tumorigenesis.

Aberrant Expression of microRNA Clusters in Head and Neck Cancer Development and Progression: Current and Future Translational Impacts

MicroRNAs are small non-coding RNAs known to negative regulate endogenous genes. Some microRNAs have high sequence conservation and localize as clusters in the genome. Their coordination is regulated by simple genetic and epigenetic events mechanism. In cells, single microRNAs can regulate multiple genes and microRNA clusters contain multiple microRNAs. MicroRNAs can be differentially expressed and act as oncogenic or tumor suppressor microRNAs, which are based on the roles of microRNA-regulated genes. It is vital to understand their effects, regulation, and various biological functions under both normal and disease conditions. Head and neck squamous cell carcinomas are some of the leading causes of cancer-related deaths worldwide and are regulated by many factors, including the dysregulation of microRNAs and their clusters. In disease stages, microRNA clusters can potentially control every field of oncogenic function, including growth, proliferation, apoptosis, migration, and intercellular commutation. Furthermore, microRNA clusters are regulated by genetic mutations or translocations, transcription factors, and epigenetic modifications. Additionally, microRNA clusters harbor the potential to act therapeutically against cancer in the future. Here, we review recent advances in microRNA cluster research, especially relative to head and neck cancers, and discuss their regulation and biological functions under pathological conditions as well as translational applications.

Blood-based circulating microRNAs as potential biomarkers for predicting the prognosis of head and neck cancer-a systematic review

OBJECTIVE

The aim of the present study was to systematically review the role of circulating miRNAs as potential prognostic biomarkers in head and neck cancer patients.

MATERIALS AND METHODS

PubMed, EMBASE, Scopus, Web of Science, and gray literature from January 1990 up to and including September 2019 were searched. The study selection was performed by two independent reviewers according to eligibility criteria.

RESULTS

A total of 13 studies that met the eligibility criteria were included. Significant number of studies were executed majorly in China and predominant number of them were case-control in nature. A total of 22 different miRNAs were found to be concomitant with very poor prognosis in cancers of the head and neck region. Of these, eighteen miRNAs (miR-375, miR-1234, miR-103, miR-638, miR-200b-3p, miR-191-5p, miR-24-3p, miR-572, miR-483-5p, miR-20a, miR-22, miR-29a, miR-29b, mir-let-7c, miR-17, miR-374b-5p, miR-425-5p, and miR-196a) were upregulated and four miRNAs (miR-9, miR-29c, miR-223, and miR-187∗) were downregulated. The hazard ratio (HR) ranged from twofold to fivefold.

CONCLUSION

Based on the results, circulating miRNA may assist in the prediction of prognosis of head and neck cancer. Further multi-center randomized controlled clinical trials with large sample size are required to validate the results of the present review.

CLINICAL RELEVANCE

Decoding the circulating miRNA profile could aid in accurate prognostication of head and neck cancer.

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.

The roles of microRNAs in the stemness of oral cancer cells

Oral cancer (OC), which is the most common form of head and neck cancers, has one of the lowest (~50%) overall 5-year survival rates. The main reasons for this high mortality rate are diagnosis of OC in advanced stages in most patients and spread to distant organs via lymph node metastasis. Many studies have shown that a small population of cells within the tumor plays vital roles in the initiation, progression, and metastasis of the tumor, resistance to chemotherapeutic agents, and recurrence. These cells, identified as cancer stem cells (CSCs), are the main reasons for the failure of current treatment modalities. Deregulated expressions of microRNAs are closely related to tumor prognosis, metastasis and drug resistance. In addition, microRNAs play important roles in regulating the functions of CSCs. Until now, the roles of microRNAs in the acquisition and maintenance of OC stemness have not been elucidated in detail yet. Here in this review, we summarized significant findings and the latest literature to better understand the involvement of CSCs in association with dysregulated microRNAs in oral carcinogenesis. Possible roles of these microRNAs in acquisition and maintenance of CSCs features during OC pathogenesis were summarized.

Evaluating the role of microRNAs alterations in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) accounts for nearly 90 percent of oral cavity malignancies and is one of the most widespread oral cancers in the world. The microRNAs (miRNAs or miRs) have an important role in cellular processes comprising cell cycle, differentiation, and also apoptosis. MiRNAs are also implicated in the progression of cancers, including OSCC, through a variety of signaling pathways. One of the most significant signaling pathways in OSCC is the PI3K / Akt pathway that has been illustrated to be under the tight regulation of miRNAs. Deregulation or activation of the PI3K / Akt pathway due to mutations has been revealed to be implicated in the development of oral cancer. According to studies, more than 47% of HNSCC and around 38% of OSCC samples indicate at least one molecular alteration in this signaling pathway. The potential of miRNAs for their use as therapeutic tools in the diagnosis as well as treatment of numerous diseases have been confirmed. In the current review, we summarize miRNAs and their possible mechanisms as well as their functions in OSCC advancement and progression.

Advanced diagnostic aids for oral cancer

Oral cancer, a universal malady, has become a stumbling block over the years due to its significant morbidity and mortality rates. The greater morbidity associated with this deadly disease is attributed to delay in its diagnosis / its presentation in advanced stage. Being multifactorial, Oral squamous cell carcinoma (OSCC) is the outcome of genetic and epigenetic instability. However, in many instances, oral cancer is preceded by precursor lesions named as oral potentially malignant disorders (OPMDs), the early detection of which makes it beneficial for patients with the possible increase in the productive longevity. Many diagnostic tools / aids have been explored with the aim of early detection of oral precancer and cancer. The basic chair-side procedures or relatively advanced aids come with a set of limitations along with subjectivity as one of the setbacks. The advent and exploitation of molecular techniques in the field of health diagnostics, is demanding the molecular typing of the OPMDs and also of oral cancer. The saga of various diagnostic aids for OSCC has witnessed the so-called latest trends such as lab-on-chip, microfluidics, nano diagnostics, liquid biopsy, omics technology and synthetic biology in early detection of oral precancer and cancer. Oral cancer being multifactorial in origin with the chief participation of altered genetics and epigenetics would demand high-end diagnostics for designing personalized therapy. Hence, the present paper highlights the role of various advanced diagnostic aids including 'omics' technology and synthetic biology in oral precancer and cancer.

Laminin 332 in cancer: When the extracellular matrix turns signals from cell anchorage to cell movement

Laminin 332 is crucial in the biology of epithelia. This large extracellular matrix protein consists of the heterotrimeric assembly of three subunits - α3, β3, and γ2 - and its multifunctionality relies on a number of extracellular proteolytic processing events. Laminin 332 is central to normal epithelium homeostasis by sustaining cell adhesion, polarity, proliferation, and differentiation. It also supports a major function in epithelial tissue formation, repair, and regeneration by buttressing cell migration and survival and basement membrane assembly. Interest in this protein increased after the discovery that its expression is perturbed in tumor cells, cancer-associated fibroblasts, and the tumor microenvironment. This review summarizes current knowledge regarding the established involvement of the laminin 332 γ2 chain in tumor invasiveness and discusses the role of its α3 and β3 subunits.

Lauric Acid Modulates Cancer-Associated microRNA Expression and Inhibits the Growth of the Cancer Cell

BACKGROUND

microRNAs are known to regulate various protein-coding gene expression posttranscriptionally. Fatty acids are cell membrane constituents and are also known to influence the biological activities of the cells like signal transduction, growth and differentiation of the cells, apoptosis induction, and other physiological functions. In our experiments, we used lauric acid to analyse its effects on human cancerous cell lines.

OBJECTIVE

Our objective was to speculate the miRNA expression profile in lauric acid treated and untreated cancerous cell lines and further study the metabolic pathways of the targeted tumour suppressor and oncogenes.

METHODS

The KB cells and HepG2 cells were treated with lauric acid and miRNA was isolated and the expression of tumour suppressor and oncogenic miRNA was measured by quantitative PCR. The untreated cells were used as control. The metabolic pathways of the target tumour suppressor and oncogenes were examined by GeneMANIA software.

RESULTS

Interestingly, the lauric acid treatment suppresses the expression of oncogenic miRNA and significantly upregulated the expression of some tumour suppressor miRNAs. GeneMANIA metabolic pathway revealed that the upregulated tumour suppressor miRNAs regulate several cancer-associated pathways such as DNA damage, signal transduction p53 class mediator, stem cell differentiation, cell growth, cell cycle phase transition, apoptotic signalling pathway, cellular response to stress and radiation, etc. whereas oncogenic miRNAs regulate the cancer-associated pathway like cell cycle phase transition, apoptotic signalling pathway, cell growth, response to oxidative stress, immune response activating cell surface protein signalling pathway, cyclin-dependent protein kinase activity, epidermal growth factor receptor signalling pathways, etc. Conclusion: In our study, we found that lauric acid works as an anticancer agent by altering the expression of miRNAs.

Circulating MicroRNAs as Prognostic Molecular Biomarkers in Human Head and Neck Cancer: A Systematic Review and Meta-Analysis

Background

Circulating microRNAs (miRNAs) are potential molecular biomarkers for cancer detection; however, little is known about their prognostic role in head and neck cancer. This current study is aimed at evaluating the role of novel miRNAs in the survival of head and neck cancer patients.

Materials and Methods

We performed a systematic literature search using online databases for articles published between December 2006 and February 2019. A meta-analysis was conducted to assess the correlation between miRNA expressions and overall survival (OS) among the selected head and neck cancer studies. After multilevel screening by reviewers, meta-analysis was performed using hazard ratios (HR) and associated 95% confidence interval (CI) of survival to calculate a pooled effect size.

Result

A total of 1577 patients across 13 studies were included in the literature review, with 18 miRNAs upregulated and 4 miRNAs downregulated predicting a poor overall survival. The forest plot generated using cumulated survival data resulted in a pooled HR value of 2.943 (95% CI: 2.394-3.618) indicating a strong association of dysregulated miRNA expression with a poor outcome. Only 2 miRNAs—low levels of miR-9 and high levels of miR-483-5p—were observed in two studies, both showing a significant association with overall cancer survival.

Conclusion

To our knowledge, this is the first comprehensive systematic review and meta-analysis that examines the prognostic role of circulating miRNAs from blood in head and neck cancer patients. The combined effect estimates a HR across multiple studies and also supports the previous individual findings that an alteration in miRNA expression is highly associated with poor prognosis. This has the potential to use serum and/or plasma miRNAs as biomarkers and become novel tools for predicting the prognosis of head and neck cancer patients in the near future.

Cluster miRNAs and cancer: Diagnostic, prognostic and therapeutic opportunities

MiRNAs are class of noncoding RNA important for gene expression regulation in many plants, animals and viruses. MiRNA clusters contain a set of two or more miRNA encoding genes, transcribed together as polycistronic miRNAs. Currently, there are approximately 159 miRNA clusters reported in the human genome consisting of miRNAs ranging from two or more miRNA genes. A large proportion of clustered miRNAs resides in and around the fragile sites or cancer associated genomic hotspots and plays an important role in carcinogenesis. Altered expression of miRNA cluster can be pro-tumorigenic or anti-tumorigenic and can be targeted for clinical management of cancer. Over the past few years, manipulation of miRNA clusters expression is attempted for experimental purpose as well as for diagnostic, prognostic and therapeutic applications in cancer. Re-expression of miRNAs by epigenetic therapy, genome editing such as clustered regulatory interspaced short palindromic repeats (CRISPR) and miRNA mowers showed promising results in cancer therapy. In this review, we focused on the potential of miRNA clusters as a biomarker for diagnosis, prognosis, targeted therapy as well as strategies for modulating their expression in a therapeutic context. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Processing > Processing of Small RNAs RNA in Disease and Development > RNA in Disease Regulatory RNAs/RNAi/Riboswitches > Biogenesis of Effector Small RNAs.

Prognostic Value of miRNAs in Head and Neck Cancers: A Comprehensive Systematic and Meta-Analysis

Head and Neck Cancer (HNC) is the sixth most common type of cancer across the globe, with more than 300,000 deaths each year, globally. However, there are currently no standardised molecular markers that assist in determining HNC prognosis. The literature for this systematic review and meta-analysis were sourced from multiple bibliographic databases. This review followed PRISMA guidelines. The Hazard Ratio (HR) was selected as the effect size metric to independently assess overall survival (OS), disease-free survival (DFS), and prognosis. Subgroup analysis was performed for individual highly represented miRNA. A total of 6843 patients across 50 studies were included in the systematic review and 34 studies were included in the meta-analysis. Studies across 12 countries were assessed, with China representing 36.7% of all included studies. The analysis of the survival endpoints of OS and DFS were conducted separately, with the overall pooled effect size (HR) for each being 1.825 (95% CI 1.527–2.181; p < 0.05) and 2.596 (95% CI 1.917–3.515; p < 0.05), respectively. Subgroup analysis was conducted for impact of miR-21, 200b, 155, 18a, 34c-5p, 125b, 20a and 375 on OS, and miR-21 and 34a on DFS. The pooled results were found to be statistically significant for both OS and DFS. The meta-analysis indicated that miRNA alterations can account for an 82.5% decrease in OS probability and a 159.6% decrease in DFS probability. These results indicate that miRNAs have potential clinical value as prognostic biomarkers in HNC, with miR-21, 125b, 34c-5p and 18a, in particular, showing great potential as prognostic molecular markers. Further large scale cohort studies focusing on these miRNAs are recommended to verify the clinical utility of these markers individually and/or in combination.

Silencing of LINC01116 suppresses the development of oral squamous cell carcinoma by up-regulating microRNA-136 to inhibit FN1

Background

Oral squamous cell carcinoma (OSCC), one of the most common cancers worldwide with a high mortality rate, is accompanied by poor prognosis, highlighting the significance of early diagnosis and effective treatment. Long non-coding RNAs (lncRNAs) have been linked with the development and progression of various cancers. In this study, aberrantly expressed lncRNA LINC01116, microRNA-136 (miR-136), and fibronectin1 (FN1) were identified in OSCC using a microarray analysis. Therefore, this study aimed to investigate the role of LINC01116/miR-136/FN1 regulatory axis in OSCC.

Methods

The gain-of-function and loss-of-function experiments in vitro were performed to alter the expression of LINC01116 and miR-136 in OSCC cells to elucidate their effects on cellular processes, including epithelial-mesenchymal transition (EMT), viability, invasion, and migration. In addition, the interaction among LINC01116, miR-136, and FN1 was identified. Additionally, the tumorigenicity and lymph node metastasis (LNM) affected by LINC01116 were observed through xenograft tumor in nude mice.

Results

LINC01116 and FN1 were abundant in both OSCC tissues and cells, while miR-136 was poorly expressed. LINC01116 could competitively bind to miR-136, which targets and negatively regulates FN1. Moreover, in response to LINC01116 silencing or miR-136 over-expression, OSCC cells exhibited diminished EMT process and inhibited cell viability, invasion, and migration in vitro, coupling with impaired tumorigenicity and LNM in vivo.

Conclusion

The fundamental findings in this study collectively demonstrate that LINC01116 silencing may inhibit the progression of OSCC via the miR-136-mediated FN1 inhibition, highlighting a promising therapeutic strategy for OSCC treatment.

MicroRNA Dysregulation in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the second most frequent cancer in humans and it can be locally invasive and metastatic to distant sites. MicroRNAs (miRNAs or miRs) are endogenous, small, non-coding RNAs of 19–25 nucleotides in length, that are involved in regulating gene expression at a post-transcriptional level. MicroRNAs have been implicated in diverse biological functions and diseases. In cancer, miRNAs can proceed either as oncogenic miRNAs (onco-miRs) or as tumor suppressor miRNAs (oncosuppressor-miRs), depending on the pathway in which they are involved. Dysregulation of miRNA expression has been shown in most of the tumors evaluated. MiRNA dysregulation is known to be involved in the development of cutaneous squamous cell carcinoma (CSCC). In this review, we focus on the recent evidence about the role of miRNAs in the development of CSCC and in the prognosis of this form of skin cancer.

CDKL1 promotes the chemoresistance of human oral squamous cell carcinoma cells to hydroxycamptothecin

CDKL1 is a cyclin-dependent kinase-like kinase that is highly expressed in diverse types of cancer cells. However, the role of CDKL1 in the chemoresistance of oral squamous cell carcinoma (OSCC) remains largely undefined. Here, we explored the role of CDKL1 in the chemoresistance of the human OSCC cell line CAL27 to hydroxycamptothecin (HCPT). Real-time quantitative polymerase chain reaction and western blotting revealed that exposure of CAL27 cells to HCPT led to a marked increase in the expression of CDKL1 at the mRNA and protein levels. Knockdown of CDKL1 significantly suppressed cell proliferation and induced cell cycle G0/G1 phase arrest in CAL27 cells based on the results of MTT and flow cytometry assays, respectively. CAL27 cells displayed attenuated biological activity of the cell population. After treatment with HCPT, whereas CDKL1 overexpression increased the resistance to HCPT of the remaining cells. Moreover, the western blot showed that the expression of cleaved-caspase 3 and phosphorylated ataxia telangiectasia mutated proteins was upregulated by HCPT treatment in CAL27 cells. Furthermore, CDKL1 overexpression partially reversed the inhibitory effects of HCPT in CAL27 cells. These results suggest that CDKL1 overexpression decreased the chemosensitivity of OSCC cells to HCPT, indicating a potential strategic approach for reversing the HCPT resistance in human OSCC.

Liquid biopsy: miRNA as a potential biomarker in oral cancer

Oral cancer is one of the leading cancers in South-Asian countries. Despite the easy access of the oral cavity, the detection and five year survival rates of OSCC patients are dismal. Identification of non-invasive biomarkers to determine the progression and recurrence of OSCC could be of immense help to patients. Recent studies on oral cancer suggest the importance of non-invasive biomarker development. Micro-RNAs (miRNAs) are one of the important components of the cell-free nucleic acids available in different body fluids. Here, we have reviewed the current understanding of circulating miRNAs as non-invasive biomarkers in different body fluids of oral cancer patients. A number of circulating miRNAs are found to be common in the body fluids of OSCC patients, while many of these are study specific, the possible sources of this variability could be due to differences in sample processing, assay procedure, clinical stage of the disease, oral habit and environmental factors. The prognostic and therapeutic significance of these circulating miRNAs are suggested by several studies. Mir-371, mir-150, mir-21 and mir-7d were found to be potential prognostic markers, while mir-134, mir-146a, mir-338 and mir-371 were associated with metastases. The prognostic markers, mir-21 and mir-7d were also found to be significantly correlated with resistance to chemotherapy, while mir-375, mir-196 and mir-125b were significantly correlated with sensitivity to radiotherapy. Despite the promising roles of circulating miRNAs, challenges still remain in unravelling the exact regulation of these miRNAs before using them for targeted therapy.

Differential expression of snoRNAs in oral squamous cell carcinomas: new potential diagnostic markers

BACKGROUND

Small nucleolar RNAs (snoRNAs) are small non-coding RNA sequences whose most studied function is ribosome biogenesis. The altered expression of snoRNA is observed in tumoral processes such as breast cancer and multiple myeloma. However, we have not found any references to snoRNAs in oral squamous cell carcinomas (OSCC) in the literature at the time this article was written.

MATERIAL AND METHODS

We have analyzed snoRNA expression in frozen OSCC tissue samples and have compared them to healthy controls. RNA was extracted from a total of eight OSCC samples and eight control samples, measuring the differential expression of small RNAs with the Affymetrix® miRNA 4.1 Array Plate microarray platform.

RESULTS

Results were analyzed using the Transcriptome Analysis Console 3.0 (TAC) software. We obtained a total of 16 deregulated snoRNAs of which one was over expressed and 15 were under expressed. SnoRNAs expression was altered in OSCC and could serve as a diagnostic marker.

MiR-20a, a novel promising biomarker to predict prognosis in human cancer: a meta-analysis

Background

Recently, microRNA-20a (miR-20a) has been reported to influence the clinical features and may have prognostic value in human cancers. The present meta-analysis assessed the prognostic role of miR-20a in various carcinomas.

Methods

Literature searches of seven electronic databases were performed for eligible articles of the prognostic role of miR-20a in human cancers. Hazard ratios (HR) for overall survival (OS), disease free survival (DFS), progression-free survival (PFS) as well as their 95% confidence intervals (95%CIs) were used to assess the influence of miR-20a expression on patient prognosis. Odds ratio (OR) and 95%CIs were applied to evaluate the correlation between miR-20a expression and clinicopathological characteristics.

Results

Based on the OS analyzed by log rank tests, there was a significant association between miR-20a levels and OS by fixed effects model. By subgroup analyses, the significance was also observed in the studies of specimen derived from blood and gastrointestinal cancer group. The independent prognostic role of miR-20a expression for the OS was observed significantly by fixed effects model. In addition, we observed significant association between miR-20a expression levels and DFS of log rank tests, DFS of cox regression. Significant relation of gender/differentiation and the expression level of miR-20a was identified.

Conclusions

Base on the findings, the elevated miR-20a expression level is related to poor prognosis of gastrointestinal cancer patients. As for other types of carcinomas, the results are still not stable and more studies are required to further identify miR-20a prognostic values. In addition, miR-20a expression level is relatively higher in women than that in men, and increased miR-20a expression level is linked to poor tumor differentiation.

Change of Circulating and Tissue-Based miR-20a in Human Cancers and Associated Prognostic Implication: A Systematic Review and Meta-Analysis

Background

Previous literatures have investigated the change of miR-20a expression level in the progression of multiple cancers and its influence on patients' survival outcome, but results of now-available evidence are inconsistent.

Objective

To elucidate the prognostic value of circulating and tissue-based miR-20a for patients with various cancers.

Methods

A systematic search and review of eligible publications were carried out in three electronic databases including the Cochrane Library, PubMed, and Embase, and the methodological quality of included studies was assessed according to Newcastle-Ottawa Scale (NOS). Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for overall survival (OS), recurrence-free survival (RFS), disease-free survival (DFS), and progressive-free survival (PFS) of each study were pooled using a random effect model.

Results

In total, 24 studies involving 4186 samples of multiple cancers published in 20 articles were included in the statistical analysis. As for circulating miR-20a, five kinds of cancers containing gastric cancer, lymphoma, glioblastoma, prostate cancer, and non-small-cell lung cancer reported upregulated level in patients compared with normal healthy control, and overexpressed circulating miR-20a could confer an unfavorable factor for OS (HR = 1.71, 95% CIs: 1.43 -2.04, p < 0.01) and DFS (HR = 1.90, 95% CIs: 1.45-2.49, p < 0.01). As for tissue-based samples, 6 kinds of malignancies including colorectal cancer, salivary adenoid cystic carcinoma, gallbladder carcinoma, colon cancer, gastrointestinal cancer, and alveolar rhabdomyosarcoma revealed upregulated miR-20a expression level compared with paired nontumorous tissue, of which high expression of miR-20a was significantly associated with poor OS (HR = 2.74, 95% CIs: 1.38-5.42, p < 0.01) and DFS (HR = 2.68, 95% CIs: 1.32-5.45, p < 0.01); meanwhile, other 5 tumors containing breast cancer, cutaneous squamous cell carcinoma, hepatocellular carcinoma, oral squamous cell carcinoma, and epithelial ovarian cancer demonstrated downregulated miR-20a expression level compared with benign tissue, of which low miR-20a expression was significantly related to shorter OS (HR = 3.48, 95% CIs: 2.00-6.06, p < 0.01) and PFS/RFS (HR = 4.05, 95% CIs: 2.89-5.66, p < 0.01).

Conclusion

Change of circulating and tissue-based miR-20a expression possesses vital prognostic implication for human cancers. Augmented expression of circulating miR-20a predicts poor survival outcome for patients with cancers. Tissue-based miR-20a level may be upregulated or downregulated depending on cancer types; in the former condition, high expression of tissue miR-20a is a risk factor for unfavorable prognosis and in the latter condition low expression of tissue miR-20a is associated with shorter survival.

Salivary MicroRNAs for Early Detection of Head and Neck Squamous Cell Carcinoma: A Case-Control Study in the High Altitude Mestizo Ecuadorian Population

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer with the highest incidence worldwide. HNSCC is often diagnosed at advanced stages, incurring significant high mortality and morbidity. The use of saliva, as a noninvasive tool for the diagnosis of cancer, has recently increased. Salivary microRNAs (miRNAs) have emerged as a promising molecular tool for early diagnosis of HNSCC. The aim was to identify the differential expression of salivary miRNAs associated with HNSCC in the high altitude mestizo Ecuadorian population. Using PCR Arrays, miR-122-5p, miR-92a-3p, miR-124-3p, miR-205-5p, and miR-146a-5p were found as the most representative ones. Subsequently, miRNAs expression was confirmed in saliva samples from 108 cases and 108 controls. miR-122-5p, miR-92a-3p, miR-124-3p, and miR-146a-5p showed significant statistical difference between cases and controls with areas under the curve (AUC) of 0.73 (p < 0.001), 0.70 (p < 0.001), 0.71 (p = 0.002), and 0.66 (p = 0.008), respectively. miRNAs were also deregulated in between HNSCC localizations. A differentiated expression of miR-122-5p between oral cancer and oropharynx cancer (AUC of 0.96 p = 0.01) was found: miR-124-3p between larynx and pharynx (AUC = 0.97, p < 0.01) and miR-146a-5p between larynx, oropharynx, and oral cavity (AUC = 0.96, p = 0.01). Moreover, miR-122-5p, miR-124-3p, miR-205-5p, and miR-146a-5p could differentiate between HPV+ and HPV- (p=0.004). Finally, the expression profiles of the five miRNAs were evaluated to discriminate HNSCC patient's tumor stages (TNM 2-4). miR-122-5p differentiates TNM 2 and 3 (p = 0.002, AUC = 0.92), miR-124-3p TNM 2, 3, and 4 (p < 0.001, AUC = 98), miR-146a-5p TNM 2 and 3 (p < 0.001, AUC = 0.97), and miR-92a-3p TNM 3 (p < 0.001, AUC = 0.99). Taken together, these findings show that altered expression of miRNAs could be used as biomarkers for HNSCC diagnosis in the high altitude mestizo Ecuadorian population.

Cell culture models of oral mucosal barriers: A review with a focus on applications, culture conditions and barrier properties

Understanding the function of oral mucosal epithelial barriers is essential for a plethora of research fields such as tumor biology, inflammation and infection diseases, microbiomics, pharmacology, drug delivery, dental and biomarker research. The barrier properties are comprised by a physical, a transport and a metabolic barrier, and all these barrier components play pivotal roles in the communication between saliva and blood. The sum of all epithelia of the oral cavity and salivary glands is defined as the blood-saliva barrier. The functionality of the barrier is regulated by its microenvironment and often altered during diseases. A huge array of cell culture models have been developed to mimic specific parts of the blood-saliva barrier, but no ultimate standard in vitro models have been established. This review provides a comprehensive overview about developed in vitro models of oral mucosal barriers, their applications, various cultivation protocols and corresponding barrier properties.

Epithelial-mesenchymal transition and microRNAs: Challenges and future perspectives in oral cancer

BACKGROUND

Head and neck cancer is the sixth most common cancer worldwide, with oral squamous cell carcinoma (OSCC) being the most representative type. OSCC is a public health problem with high morbidity and poor survival rate. Epithelial-mesenchymal transition is emerging as a hallmark in OSCC.

METHODS

In this study, we described the role of microRNAs in epithelial-mesenchymal transition regulation in OSCC based on a PubMed search using articles published in English between January 1, 2010, and January 31, 2018.

RESULTS

MicroRNA's regulatory networks seem to be a hallmark of epithelial-mesenchymal transition in OSCC pathophysiology becoming a growing challenge to design new studies and strategies from biology to clinical applications.

CONCLUSION

Therefore, we propose that targeting therapies to epithelial-mesenchymal transition-type cells, namely, coordinating microRNAs and/or hydrophobic drugs, such as conventional therapy, could be a promising strategy to improve the outcomes of patients with OSCC.

Quantifying the prognostic significance of microRNA-17/17-5P in cancers: a meta-analysis based on published studies

Objective

The aim of this study was to investigate the prognostic value of mircoRNA-17 and mircoRNA-17-5P (miR-17/17-5P) in patients with cancer.

Materials and methods

We conducted a comprehensive search on published literature following the guidelines of the meta-analysis of observational studies in epidemiology group for design, implementation, and reporting. The methodological qualities for included studies were assessed using the quality in prognosis studies. The pooled hazard ratios (HRs) with 95% CIs for overall survival (OS) and progression-free survival/recurrence-free survival/disease-free survival (PFS/RFS/DFS) were calculated to appraise the associations between miR-17/17-5P expression and cancer prognosis.

Results

A total of 21 studies involving 2099 subjects were analyzed in evidence synthesis. The results showed that high expression of miR-17 was associated with poor OS (HR=2.14; 95% CI: 1.69-2.71, P<0.001) in patients with cancer, especially in Caucasian (HR=2.23; 95% CI: 1.58-3.14, P<0.001) and digestive tract cancer (HR=1.29, 95% CI: 1.03-1.63, P=0.03), and miR-17 expression was significantly correlated with PFS/RFS in cancer patients (HR=1.69, 95% CI: 1.29-2.22, P<0.001). miR-17-5P overexpression was significantly linked with poor OS in cancer patients (HR=1.66; 95% CI: 1.31-2.09, P=0.00), especially in Asian (HR=1.81; 95% CI: 1.37-2.40, P<0.001), digestive tract cancer (HR=1.80; 95% CI: 1.29-2.50, P<0.001), and serum sample (HR=1.76; 95% CI: 1.29-2.41, P<0.001). miR-17-5P expression was significantly associated with DFS in cancer patients (HR=1.58, 95% CI: 1.07-2.35, P=0.02).

Conclusion

High expression of miR-17 and miR-17-5P are significantly associated with poor survival in patients with cancer. This indicated that miR-17/17-5P may be a novel prognostic indicator in cancer.

[Preparation of multifunctional nanoparticles targeting tongue cancer and in vitro study]

OBJECTIVE

This study aims to prepare docetaxel (DOC)-loaded multifunctional nanoparticles containing indocyanine green (ICG) and perfluorohexane (PFH) as targeted drug delivery system, which is supplemented with stromal cellderived factor-1 (SDF-1), and characterize their properties.

METHODS

Multifunctional nanoparticles were prepared by using the double emulsion method. SDF-1 was covalently conjugated to the surface of the nanoparticles through thioether bonding. Their particle size, distribution, and surface potential were determined with the Malvern measuring instrument. The conjugation of SDF-1 was evaluated by confocal laser scanning microscope. Encapsulation efficiency (ELC), drug loading capacity (DLC), and release regularity of the nanoparticles were determined by high-performance liquid chromatography (HPLC). In vitro photothermal property was recorded by a thermal imager. The in vitro imaging capacity was observed by a photoacoustic instrument and an ultrasonic diagnostic apparatus. Targeting capability was assessed by flow cytometry. The cell activity on SCC-15 cells was checked by CCK-8 method.

RESULTS

The targeted multifunctional nanoparticles showed regularly sphericity. The diameter was (502.88±17.92) nm. The zeta potential was (-11.5±3.15) mV. ELC was 54.12%±1.74%. DLC was 1.08 mg·mL-1. In vitro drug release was initially fast and subsequently slow. The photothermal characteristics were related to the concentration; the higher the concentration, the higher the temperature. Nanoparticles could detect significant photoacoustic and ultrasound signals. The in vitro targeting rate was 89.99%. No significant differences of cell viability in the SINPs groups were observed at each concentration (P>0.05). The inhibition effect of DOC-SINPs was stronger than that of SINPs whether or not in the presence of laser irradiation among the groups of 150 and 200 μg·mL-1 (P<
0.05).

CONCLUSIONS

Multifunctional nanoparticles for diagnosis and treatment were successfully prepared and displayed dualmode ultrasound/photoacoustic imaging and antitumor effects of chemotherapy and photothermal therapy.

MicroRNA-17 and the prognosis of human carcinomas: a systematic review and meta-analysis

OBJECTIVE

Although the role of microRNA-17 (miR-17) has been identified as a tumour biomarker in various studies, its prognostic value in cancers remains unclear. Therefore, we performed a systematic review and meta-analysis to analyse and summarise the relationship between the miR-17 status and clinical outcome in a variety of human cancers.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of Science and Embase from the first year of records to 15 May 2017.

OUTCOMES

The patients' survival results were pooled, and pooled HRs with 95% CIs were calculated and used for measuring the strength of association between miR-17 and the prognosis of cancers, including hepatocellular carcinoma, lung cancer, osteosarcoma, glioma, T-cell lymphoblastic lymphoma and colon cancer. Heterogeneity, publication bias and subgroup analysis were also conducted.

RESULTS

A total of 1096 patients were included in this meta-analysis from 12 articles. The results indicated that the increased expression of miR-17 played an unfavourable role in overall survival in various human carcinomas with the HR of 1.342 taking into account the publication bias. In subgroup analysis, HR of ethnicity (non-Asian HR=1.48 and Asian HR=1.40), disease (digestive system HR=1.36 and blood system cancer (HR=2.38) were significant with P<0.05. For the analysis of disease-free survival and recurrence-free survival, the increased expression of miR-17 was associated with unfavourable prognosis (HR=1.40).

CONCLUSIONS

miR-17 may be a useful biomarker in predicting the clinical outcome of human cancers, but due to the limitations of the current studies, further verification of the role of miR-17 in human malignancies is urgently needed.

PROSPERO REGISTRATION NUMBER

CRD42017065749.

Clustered miRNAs and their role in biological functions and diseases

MicroRNAs (miRNAs) are endogenous, small non-coding RNAs known to regulate expression of protein-coding genes. A large proportion of miRNAs are highly conserved, localized as clusters in the genome, transcribed together from physically adjacent miRNAs and show similar expression profiles. Since a single miRNA can target multiple genes and miRNA clusters contain multiple miRNAs, it is important to understand their regulation, effects and various biological functions. Like protein-coding genes, miRNA clusters are also regulated by genetic and epigenetic events. These clusters can potentially regulate every aspect of cellular function including growth, proliferation, differentiation, development, metabolism, infection, immunity, cell death, organellar biogenesis, messenger signalling, DNA repair and self-renewal, among others. Dysregulation of miRNA clusters leading to altered biological functions is key to the pathogenesis of many diseases including carcinogenesis. Here, we review recent advances in miRNA cluster research and discuss their regulation and biological functions in pathological conditions.

Migration/Invasion of Malignant Gliomas and Implications for Therapeutic Treatment

Malignant tumors of the central nervous system (CNS) are among cancers with the poorest prognosis, indicated by their association with tumors of high-level morbidity and mortality. Gliomas, the most common primary CNS tumors that arise from neuroglial stem or progenitor cells, have estimated annual incidence of 6.6 per 100,000 individuals in the USA, and 3.5 per 100,000 individuals in Taiwan. Tumor invasion and metastasis are the major contributors to the deaths in cancer patients. Therapeutic goals including cancer stem cells (CSC), phenotypic shifts, EZH2/AXL/TGF-β axis activation, miRNAs and exosomes are relevant to GBM metastasis to develop novel targeted therapeutics for GBM and other brain cancers. Herein, we highlight tumor metastasis in our understanding of gliomas, and illustrate novel exosome therapeutic approaches in glioma, thereby paving the way towards innovative therapies in neuro-oncology.

Hypoxia induced EMT: A review on the mechanism of tumor progression and metastasis in OSCC

Hypoxia, a condition of low oxygen tension in tissues, has emerged as a crucial factor in tumor pathophysiology. Hypoxic microenvironment gives rise to altered cellular metabolism and triggers varied molecular responses. These responses promote tumor progression and confer radiation resistance and chemo resistance to tumors. The predominant molecules that are associated with hypoxia research are the hypoxia inducible factors (HIFs). HIFs are known to regulate a large group of genes that are involved in cell survival, proliferation, motility, metabolism, pH regulation, extracellular matrix function, inflammatory cell recruitment and angiogenesis by inducing the expression of their downstream target genes. The process of epithelial to mesenchymal transition (EMT) has been associated with metastasis in cancer. Reports also suggest that hypoxia triggers EMT in several types of cancer including breast cancer, prostate cancer and oral cancer. Oral cancer is a predominant cancer in Central and South East Asia. However, in the recent times, the incidence rates of oral cancer have been increasing in Northern and Eastern Europe as well. This review articulates the role of hypoxia and the associated factors like HIFs in inducing EMT in oral cancer (OSCC).

Predictive Prognostic Value of Tissue-Based MicroRNA Expression in Oral Squamous Cell Carcinoma: A Systematic Review and Meta-analysis

Oral squamous cell carcinoma (OSCC) is a common type of cancer characterized by a low survival rate, mostly due to local recurrence and metastasis. In view of the importance of predicting tumor behavior in the choice of treatment strategies for OSCC, several studies have attempted to investigate the prognostic value of tissue biomarkers, including microRNA (miRNA). The purpose of this study was to perform a systematic review and meta-analysis to evaluate the relationship between miRNA expression and survival of OSCC patients. Studies were identified by searching on MEDLINE/PubMed, SCOPUS, Web of Science, and Google Scholar. Quality assessment of studies was performed with the Newcastle-Ottawa Scale. Data were collected from cohort studies comparing disease-free survival and overall survival in patients with high miRNA expression compared to those with low expression. A total of 15 studies featuring 1,200 OSCC samples, predominantly from Asia, met the inclusion criteria and were included in the meta-analysis. Poor prognosis correlated with upregulation of 9 miRNAs (miR-21, miR-455-5p, miiR-155-5p, miR-372, miR-373, miR-29b, miR-1246, miR-196a, and miR-181) and downregulation of 7 miRNAs (miR-204, miR-101, miR-32, miR-20a, miR-16, miR-17, and miR-125b). The pooled hazard ratio values (95% confidence interval) related to different miRNA expression for overall survival and disease-free survival were 2.65 (2.07–3.39) and 1.95 (1.28–2.98), respectively. The results of this meta-analysis revealed that the expression levels of specific miRNAs can robustly predict prognosis of OSCC patients.

MicroRNA-196a-5p is a potential prognostic marker of delayed lymph node metastasis in early-stage tongue squamous cell carcinoma

MicroRNAs (miRs) are expected to serve as prognostic tools for cancer. However, many miRs have been reported as prognostic markers of recurrence or metastasis in oral squamous cell carcinoma patients. We aimed to determine the prognostic markers in early-stage tongue squamous cell carcinoma (TSCC). Based on previous studies, we hypothesized that miR-10a, 10b, 196a-5p, 196a-3p, and 196b were prognostic markers and we retrospectively performed miR expression analyses using formalin-fixed paraffin-embedded sections of surgical specimens. Total RNA was isolated from cancer tissues and adjacent normal tissue as control, and samples were collected by laser-capture microdissection. After cDNA synthesis, reverse transcription-quantitative polymerase chain reaction was performed. Statistical analyses for patient clinicopathological characteristics, recurrence/metastasis, and survival rates were performed to discern their relationships with miR expression levels, and the 2^−ΔΔCq method was used. miR-196a-5p levels were significantly upregulated in early-stage TSCC, particularly in the lymph node metastasis (LNM) group. The LNM-free survival rate in the low miR-196a-5p ΔΔCq value regulation group was found to be lower than that in the high ΔΔCq value regulation group (P=0.0079). Receiver operating characteristic analysis of ΔΔCq values revealed that miR-196a-5p had a P-value=0.0025, area under the curve=0.740, and a cut-off value=−0.875 for distinguishing LNM. To our knowledge, this is the first study to examine LNM-related miRs in early-stage TSCC as well as miRs and ‘delayed LNM’ in head and neck cancer. miR-196a-5p upregulation may predict delayed LNM. Our data serve as a foundation for future studies to evaluate miR levels and facilitate the prediction of delayed LNM during early-stage TSCC, which prevent metastasis when combined with close follow-up and aggressive adjuvant therapy or elective neck dissection. Moreover, our data will serve as a foundation for future studies to evaluate whether miR-196a-5p can serve as a therapeutic marker for preventing metastasis.

A Looking-Glass of Non-coding RNAs in oral cancer

Oral cancer is a multifactorial pathology and is characterized by the lack of efficient treatment and accurate diagnostic tools. This is mainly due the late diagnosis; therefore, reliable biomarkers for the timely detection of the disease and patient stratification are required. Non-coding RNAs (ncRNAs) are key elements in the physiological and pathological processes of various cancers, which is also reflected in oral cancer development and progression. A better understanding of their role could give a more thorough perspective on the future treatment options for this cancer type. This review offers a glimpse into the ncRNA involvement in oral cancer, which can help the medical community tap into the world of ncRNAs and lay the ground for more powerful diagnostic, prognostic and treatment tools for oral cancer that will ultimately help build a brighter future for these patients.