A quest for miRNA bio-marker: a track back approach from gingivo buccal cancer to two different types of precancers

Analysis of oral lichen planus severity on micro-RNA linked with malignant transformation risks

OBJECTIVE

The present study evaluated the oral tissue expression of micro-RNA (miRNAs) linked to the potential malignant evolution of oral lichen planus (OLP). Furthermore, the correlation between OLP severity and miRNAs expression was assessed, and possible predictors of miRNAs in OLP patients were identified.

METHODS

The present study enrolled 41 patients with OLP (median age 58 years) and 42 healthy controls (median age 59 years). In each patient, miRNA levels (miR-7a-3p,-7a2-3p,-7a-5p,-21-3p,-21-5p,-100-3p,-100-5p,-125b-2-3p,-125b-5p,-200b-3p,-200b-5p) were assessed and analyzed through reverse transcription polymerase chain reaction. Clinical parameters and the eventual presence of OLP symptoms, signs, and disease severity scores in each patient were reported using an anamnestic questionnaire.

RESULTS

In comparison with healthy controls, OLP patients showed significantly higher miR-7a-3p,-7a-2-3p,-21-3p, miR-21-5p and miR-100-5p levels (p < 0.05) and significantly lower miR-125b-2-3p,-125b-5p,-200b-3p, and -200b-5p levels (p < 0.05). Furthermore, OLP symptoms and signs and disease severity scores were significantly correlated and were also predictors of all analyzed miRNAs (p < 0.05).

CONCLUSIONS

In comparison with healthy subjects, OLP patients exhibited unbalanced oral miRNAs expression linked to the risk of potential malignant evolution of OLP. Furthermore, some miRNAs were correlated with OLP extent and were significant predictors of OLP symptoms, signs, and disease severity scores.

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 genomic and proteomic landscape in oral lichen planus versus oral squamous cell carcinoma: a scoping review

BACKGROUND

Oral lichen planus (OLP), a World Health Organization (WHO)-classified oral potentially malignant condition, confers a 1% risk of transformation to oral squamous cell carcinoma (OSCC). There does not appear to be a consensus understanding of the underlying molecular events. This scoping review aimed to identify critical molecular pathways and highlight gaps in existing knowledge on malignant transformation in OLP.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) guidelines, a comprehensive literature search and methodical screening identified 61 relevant studies detailing molecular differences between OLP and OSCC.

RESULTS

Molecular changes shared between OLP and OSCC included those affecting cellular proliferation (altered p53 expression, hypermethylation of p16/CDKN2A, MYC gains, increased ki-67), apoptosis (increased bcl-2 and survivin expression), extracellular matrix (ECM) remodeling (increased matrix metalloproteinase [MMP] expression), and transcriptional control (altered bmi1 and microRNA [miRNA] expression). In addition, some molecular alterations accumulated incrementally from control to OLP to OSCC or were present in higher-risk erosive variants of OLP or transformed OLP. Few studies included rigorous diagnostic inclusion criteria or unbiased discovery methods.

CONCLUSIONS

Results of this review support the potentially malignant nature of OLP and imply that molecular events associated with malignant transformation may be heterogeneous. In addition, findings in this review highlight the need for additional studies using rigorous diagnostic inclusion criteria and unbiased discovery methods to further understand this process.

Bioinformatics analysis of tumor-educated platelet microRNAs in patients with hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies that seriously threaten global health. The primary reason for its grim prognosis is the lack of sensitive tools for early diagnosis. The purpose of the present study was to apply bioinformatics analysis to explore tumor-educated platelet (TEP) microRNA (miRNA) expression and its potential diagnostic utility in HCC.

Methods: Twenty-five HCC patients and 25 healthy controls were included. RNA sequencing was utilized to screen miRNA alterations in platelets derived from HCC patients (n=5) and controls (n=5). Gene set enrichment analysis was performed to analyze the targeted mRNAs of differentially expressed miRNAs by using the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, aiming at main functions and pathways, respectively. We then verified the selected platelet miRNAs in another cohort by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) amplification.

Results: A total of 250 differentially expressed miRNAs were identified, among which 111 were down-regulated and 139 were up-regulated. The functional enrichment analysis of differentially expressed miRNAs suggested that their target genes were involved primarily in pathways related to HCC. Expression levels of miR-495-3p and miR-1293 were further validated by qRT-PCR, which yielded results consistent with the sequencing analysis. The area under the receiver operating characteristic (ROC) curve of miR-495-3p and miR-1293 as diagnostic tests for HCC were 0.76 and 0.78, respectively.

Conclusion: TEP miRNAs such as miR-495-3p and miR-1293 were differentially expressed in HCC patients, and may be involved in the pathophysiology of HCC.

A Systematic Review of MicroRNA Signatures Associated with the Progression of Leukoplakia with and without Epithelial Dysplasia

Oral cancer is a significant public health issue, being the eighth most common cancer worldwide with over 300,000 cases diagnosed annually. Early diagnosis and adequate management of oral potentially malignant disorders (OPMDs) before transformation into oral squamous cell carcinoma (OSCC) is critical to reduce deaths, morbidity, and to improve overall prognosis. MicroRNAs (miRNAs) are small noncoding RNAs involved in the post-transcriptional regulation of protein expression and implicated in the control of numerous cellular pathways and impacting physiological, developmental, and pathological processes. Dysregulation of miRNAs has been reported in many cancers and has been demonstrated to play a critical role in cancer initiation, progression, apoptosis, invasion and metastasis. This systematic review provides a comprehensive summary of the prevailing literature on miRNA signatures in OPMDs, specifically leukoplakia with or without oral epithelial dysplasia, and their utility in predicting malignant transformation into OSCC. Eighteen articles describing 73 unique and differentially expressed microRNAs met the criteria for inclusion in this review. We reviewed the characteristics and methodology for each of these studies and assessed the sensitivity and specificity of the studied miRNAs in predicting malignant transformation. This systematic review highlights the significant interest in miRNAs and their tremendous potential as prognostic markers for predicting the malignant transformation of OPMDs into OSCC.

miR-1293 acts as a tumor promotor in lung adenocarcinoma via targeting phosphoglucomutase 5

Background

Lung adenocarcinoma (LUAD) is the most common histologic subtype of lung cancer. Studies have found that miR-1293 is related to the survival of LUAD patients. Unfortunately, its role in LUAD remains not fully clarified.

Methods

miR-1293 expression and its association with LUAD patients’ clinical characteristics were analyzed in TCGA database. Also, miR-1293 expression was detected in LUAD cell lines. Cell viability, migration, invasion and expression of MMP2 and MMP9 were measured in LUAD cells following transfection with miR-1293 mimic or antagomir. Phosphoglucomutase (PGM) 5 was identified to be negatively related to miR-1293 in LUAD patients in TCGA database, and their association was predicated by Targetscan software. Hence, we further verified the relationship between miR-1293 and PGM5. Additionally, the effect and mechanism of miR-1293 were validated in a xenograft mouse model.

Results

We found miR-1293 expression was elevated, but PGM5 was decreased, in LUAD patients and cell lines. Higher miR-1293 expression was positively related to LUAD patients’ pathologic stage and poor overall survival. miR-1293 mimic significantly promoted, whereas miR-1293 antagomir suppressed the viability, migration, invasion, and expression of MMP2 and MMP9 in LUAD cells. PGM5 was a target of miR-1293. Overexpression of PGM5 abrogated the effects of miR-1293 on the malignant phenotypes of LUAD cells. Administration of miR-1293 antagomir reduced tumor volume and staining of Ki-67 and MMP9, but elevated PGM5 expression in vivo.

Conclusions

miR-1293 promoted the proliferation, migration and invasion of LUAD cells via targeting PGM5, which indicated that miR-1293 might serve as a potential therapeutic target for LUAD patients.

Identification of Three Differentially Expressed miRNAs as Potential Biomarkers for Lung Adenocarcinoma Prognosis

OBJECTIVE

The aim of this study areto screen MicroRNAs (miRNAs) related to the prognosis of lung adenocarcinoma (LUAD) and to explore the possible molecular mechanisms.

METHODS

The data for a total of 535 patients with LUAD data were downloaded from The Cancer Genome Atlas (TCGA) database. The miRNAs for LUAD prognosis were screened by both Cox risk proportional regression model and Last Absolute Shrinkage and Selection Operator (LASSO) regression model. The performances of the models were verified by time-dependent Receiver Operating Characteristic (ROC) curve. The possible biological processes linked to the miRNAs' target genes were analyzed by Gene Ontology (GO), Kyoto gene and genome encyclopedia (KEGG).

RESULTS

Among 127 differentially expressed miRNAs identified from the screening analysis, there are 111 up-regulated and 16 down-regulated miRNAs. Three of them, hsa-miR-1293, hsa-miR-490 and hsa-miR- 5571, were also significantly associated with the survival of the LUAD patients. The targets of the three miRNAs are significantly enriched in systemic lupus erythematosus pathways.

CONCLUSION

Hsa-miR-1293, hsa-miR-490 and hsa-miR-5571 can be potentially used as novel biomarkers for the prognosis prediction of LUAD.

miR-1293 Suppresses Tumor Malignancy by Targeting Hydrocyanic Oxidase 2: Therapeutic Potential of a miR-1293/Hydrocyanic Oxidase 2 Axis in Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a common cancer, and extensive research suggests that microRNA may play an important role in the progression of RCC. The emphasis of this article was to reveal the function and mechanism of microRNA-1293(miR-1293) in the development of RCC tumors. First, the authors carried out bioinformatics analysis. The differential expression of miR-1293 in RCC tumor and normal cells was analyzed using the data from The Cancer Genome Atlas database, and Kaplan-Meier survival analysis was carried out to test the survival rate. Subsequently, the miR-1293 expression in RCC cell lines was examined by quantitative real-time PCR. Then Cell counting kit-8 and Transwell assays were executed to detect the function of miR-1293 in RCC. Bioinformatics prediction, western blotting, and dual-luciferase reporter assay were set to check the target gene of miR-1293. Finally, they conducted rescue experiments to verify whether the regulation of miR-1293 on the biological function of RCC cells was achieved by regulating hydrocyanic oxidase 2 (HAO2). Bioinformatics results showed that miR-1293 was highly expressed in RCC, and the miR-1293 high-expression group showed a lower survival rate than the miR-1293 low-expression group, which suggested that the high expression of miR-1293 was related to unfavorable prognosis in RCC. Subsequent assays evidenced that upregulation of miR-1293 expression significantly increased the cell viability and promoted cell migration and invasion in RCC. Silencing miR-1293 expression showed opposite results. Furthermore, HAO2 was confirmed to be a direct target gene of miR-1293 by dual-luciferase reporter assay, and miR-1293 negatively regulated the expression of HAO2. Moreover, rescue experiments evidenced that miR-1293 reduced the cell viability, invasion, and migration of RCC by regulating HAO2. In sum, miR-1293 can regulate the viability, invasion, and migration of RCC tumor cells by targeting HAO2, suggesting that miR-1293 can be used as a new biomarker for clinical treatment of RCC.

Validation of microRNA expression profile in Oral Lichenoid Disease through cytological samples

Background

To validate oral exfoliative cytology in the analysis of the microRNA expression profile in Oral Lichenoid Disease (OLD).

Material and Methods

The expression of 13 microRNAs identified and presented by our group in a previous study was analyzed in 26 cases, 16 diagnosed as OLD and 10 controls with no oral mucosal pathology. Cytological samples from the oral mucosa obtained using an Orcellex toothbrush were analyzed using RT-qPCR and TaqMan microRNA assays.

Results

The aberrant expression was validated for 2 microRNAs (miR-146a-5p and miR-7-1-3p) of those previously recognized in the biopsy study.

Conclusions

This is the first time that oral exfoliative cytology is validated in a study of the alterations of the expression of microRNAs in OLD. The alteration of miR-146a and miR-7 compared to controls was validated. These microRNAs are associated with both inflammatory and carcinogenic phenomena that are involved in the etiopathogenesis of this potentially malignant oral disorder.

Key words:microRNAs, lichen planus, epigenetics, cytological techniques.

Genome-wide miRNA methylome analysis in oral cancer: possible biomarkers associated with patient survival

AIM

The methylome associated with miRNA loci was investigated in oral cancer to explore tobacco specific methylation and potential biomarkers for patient survival.

METHODS

Methylome data was generated from 16 pairs of cancer-normal tissues by reduced representation bisulfite sequencing method. Differentially methylated regions were identified using the DMAP pipeline. In silico validation and Kaplan-Meier survival analyses were performed on The Cancer Genome Atlas data based on our miRNA methylome data.

RESULTS

A total of 4310 unique differentially methylated regions, mapping to 144 miRNA loci, were identified. Three distinct groups of miRNAs were differentially methylated in cancer tissues from smokers, chewers and mixed habitués. Hypermethylation of miR-503, miR-200a/b, miR-320b and miR-489 was associated with worse 5-year survival.

CONCLUSION

Differential methylation patterns in miRNA loci are associated with poor survival underscoring their potential as predictive and prognostic biomarkers in oral cancer.

A novel bayesian multiple testing approach to deregulated miRNA discovery harnessing positional clustering

MicroRNAs (miRNAs) are small non-coding RNAs that function as regulators of gene expression. In recent years, there has been a tremendous interest among researchers to investigate the role of miRNAs in normal as well as in disease processes. To investigate the role of miRNAs in oral cancer, we analyse expression levels of miRNAs to identify miRNAs with statistically significant differential expression in cancer tissues. In this article, we propose a novel Bayesian hierarchical model of miRNA expression data. Compelling evidence has demonstrated that the transcription process of miRNAs in the human genome is a latent process instrumental for the observed expression levels. We take into account positional clustering of the miRNAs in the analysis and model the latent transcription phenomenon nonparametrically by an appropriate Gaussian process. For the purpose of testing, we employ a novel Bayesian multiple testing method where we mainly focus on utilizing the dependence structure between the hypotheses for better results, while also ensuring optimality in many respects. Indeed, our non-marginal method yielded results in accordance with the underlying scientific knowledge which are found to be missed by the very popular Benjamini-Hochberg method.

Diagnostic and prognostic relevance of salivary microRNA-21, -125a, -31 and -200a levels in patients with oral lichen planus - a short report

BACKGROUND

Oral lichen planus (OLP), a relatively common chronic inflammatory disease of the oral mucosa, is considered to be a premalignant disorder of the oral cavity. Previously, several biomarkers have been tested for their diagnostic potential. Here, we aimed to investigate the diagnostic potential of four miRNAs, miR-21, -125a, -31 and -200a, known to be involved in oral squamous cell carcinoma (OSCC) development, in the saliva of OLP patients as also their putative relation to OSCC development in these patients.

MATERIALS AND METHODS

Saliva samples from 30 patients with OLP were collected, 15 of whom were diagnosed with dysplasia upon histopathologic examination. In addition, 15 saliva samples from patients with OSCC and 15 saliva samples from healthy donors were collected. After RNA extraction, the respective miRNA levels were assessed by quantitative RT-PCR.

RESULTS

We found that the miR-21 levels were significantly increased in saliva samples derived from patients with OLP, dysplastic OLP and OSCC, compared to those from healthy controls (p = 0.012, p = 0.0017 and p < 0.0001, respectively). Conversely, significant decreases in miR-125a levels were found in the OLP, dysplastic OLP and OSCC samples, compared to those from healthy controls (p < 0.0014, p < 0.0001 and p < 0.0001, respectively). In addition, significant increases in miR-31 levels were found in samples derived from dysplastic OLP and OSCC patients, but not in those from nondysplastic OLP patients, compared to those in healthy controls (p = 0.01 and p = 0.004, respectively). Finally, we found that the miR-200a levels were significantly decreased only in samples derived from OSCC patients (p < 0.0001).

CONCLUSIONS

From our data we conclude that increased miR-21 levels in conjunction with decreased miR-125a levels in saliva of OLP patients may be indicative for a poor prognosis. Conversely, we conclude that lack of significant alterations in miR-31 and miR-200a levels in saliva of OLP patients may be indicative for absence of malignant transformation.

Characteristic miRNA expression signature and random forest survival analysis identify potential cancer-driving miRNAs in a broad range of head and neck squamous cell carcinoma subtypes

AIM

To characterize the miRNA expression profile in head and neck squamous cell carcinoma (HNSSC) accounting for a broad range of cancer subtypes and consequently identify an optimal miRNA signature with prognostic value.

BACKGROUND

HNSCC is consistently among the most common cancers worldwide. Its mortality rate is about 50% because of the characteristic aggressive behavior of these cancers and the prevalent late diagnosis. The heterogeneity of the disease has hampered the development of robust prognostic tools with broad clinical utility.

MATERIALS AND METHODS

The Cancer Genome Atlas HNSC dataset was used to analyze level 3 miRNA-Seq data from 497 HNSCC patients. Differential expression (DE) analysis was implemented using the limma package and multivariate linear model that adjusted for the confounding effects of age at diagnosis, gender, race, alcohol history, anatomic neoplasm subdivision, pathologic stage, T and N stages, and vital status. Random forest (RF) for survival analysis was implemented using the randomForestSRC package.

RESULTS

A characteristic DE miRNA signature of HNSCC, comprised of 11 upregulated (i.e., miR-196b-5p, miR-1269a, miR-196a-5p, miR-4652-3p, miR-210-3p, miR-1293, miR-615-3p, miR-503-5p, miR-455-3p, miR-205-5p, and miR-21-5p) and 9 downregulated (miR-376c-3p, miR-378c, miR-29c-3p, miR-101-3p, miR-195-5p, miR-299-5p, miR-139-5p, miR-6510-3p, miR-375) miRNAs was identified. An optimal RF survival model was built from seven variables including age at diagnosis, miR-378c, miR-6510-3p, stage N, pathologic stage, gender, and race (listed in order of variable importance).

CONCLUSIONS

The joint differential miRNA expression and survival analysis controlling for multiple confounding covariates implemented in this study allowed for the identification of a previously undetected prognostic miRNA signature characteristic of a broad range of HNSCC.

Assessing miRNAs profile expression as a risk stratification biomarker in oral potentially malignant disorders: A systematic review

OBJECTIVES

This paper aims to systematically review current findings on altered expression of miRNAs in OPMDs and whether they can be used as risk stratification biomarkers.

METHODS

Studies were collated after searching three different electronic databases: PubMed, Embase, Medline. Additional searches were carried out through cross checking the bibliographies of selected articles. After a thorough selection process made by two of the authors, 40 articles met the inclusion criteria and were included in the review. Studies were assessed and analysed in terms of how the candidate miRNA biomarkers were differentially expressed and validated.

RESULTS

The included studies examined the expression of miRNAs from human specimens (blood serum/plasma, saliva, tissue) as diagnostic or prognostic biomarkers in patients with OPMDs, some of which have been utilised as risk stratification biomarkers for malignant transformation and have showed promising findings.

CONCLUSION

The current evidence to support or refute the prognostic utility of miRNAs in predicting cancer progression in OPMDs is equivocal. Further longitudinal prospective studies with solid study design are warranted.

Rapid Decrease in KRT14 and TP53 mRNA Expression in the Buccal Mucosa of Patients Receiving Total-Body Irradiation for Allogeneic Stem Cell Transplantation

The only curative treatment option for relapsed patients with acute myeloid leukemia (AML) is allogeneic stem cell transplantation. Depletion of hematopoietic stem cells and leukemic blast cells is achieved through the systemic administration of DNA damaging agents, including total-body irradiation (TBI) prior to transplantation. Since other tissues are radiosensitive, the identification of biomarkers could facilitate the management of additional toxicities. Buccal keratinocytes are readily accessible and could provide a source of cells for RNA analysis. In this study, we obtained miRNAs and mRNAs from daily buccal swabs collected from patients undergoing allogeneic stem cell transplantation. Unexpectedly, there was no prominent p53-induced mRNA or miRNA response in these samples, despite the fact that the p53 pathway is a well-characterized radiation-inducible response. Instead, the expression of mRNAs encoding p53 and cytokeratin 14 (TP53 and KRT14, respectively) decreased precipitously within hours of the first radiation treatment. These patients went on to develop oral mucositis, however, it is unclear whether TP53 and/or KRT14 expression are predictive of this adverse event. Larger scale analysis of buccal epithelial samples from patients undergoing allogeneic stem cell transplantation appears to be warranted.

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

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

Analysis of the whole transcriptome from gingivo-buccal squamous cell carcinoma reveals deregulated immune landscape and suggests targets for immunotherapy

Background

Gingivo-buccal squamous cell carcinoma (GBSCC) is one of the most common oral cavity cancers in India with less than 50% patients surviving past 5 years. Here, we report a whole transcriptome profile on a batch of GBSCC tumours with diverse tobacco usage habits. The study provides an entire landscape of altered expression with an emphasis on searching for targets with therapeutic potential.

Methods

Whole transcriptomes of 12 GBSCC tumours and adjacent normal tissues were sequenced and analysed to explore differential expression of genes. Expression changes were further compared with those in TCGA head and neck cohort (n = 263) data base and validated in an independent set of 10GBSCC samples.

Results

Differentially expressed genes (n = 2176) were used to cluster the patients based on their tobacco habits, resulting in 3 subgroups. Immune response was observed to be significantly aberrant, along with cell adhesion and lipid metabolism processes. Different modes of immune evasion were seen across 12 tumours with up-regulation or consistent expression of CD47, unlike other immune evasion genes such as PDL1, FUT4, CTLA4 and BTLA which were downregulated in a few samples. Variation in infiltrating immune cell signatures across tumours also indicates heterogeneity in immune evasion strategies. A few actionable genes such as ITGA4, TGFB1 and PTGS1/COX1 were over expressed in most samples.

Conclusion

This study found expression deregulation of key immune evasion genes, such as CD47 and PDL1, and reasserts their potential as effective immunotherapeutic targets for GBSCC, which requires further clinical studies. Present findings reiterate the idea of using transcriptome profiling to guide precision therapeutic strategies.

The role of microRNAs in oral lichenoid disorders. Systematic review

Background

Certain changes in the microRNA expression are considered to be associated with chronic inflammatory processes and with the malignant transformation of oral potentially malignant disorders. The purpose of this systematic review is to update the existing data on the aberrant microRNA expression profiles identified in oral lichenoid disease (OLD).

Material and Methods

A search in PubMed-Medline and Scopus was performed on the English literature published between 2010 and August 2016 using the following keywords: oral lichenoid disease, oral lichen planus and microRNA.

Results

Originally, 25 articles were considered, of which 12 case-control articles were selected according to the inclusion/exclusion criteria.

Conclusions

OLD seems to have altered microRNA expression profile. Certain altered microRNAs (146a, 155) may be useful as biomarkers for this disorder. More studies including larger number of cases are needed in order to study further on the biological processes and on the regulation pathways of these altered microRNAs.

Key words:microRNAs, oral lichenoid disease, oral lichen planus.

microRNAs: Emerging players in oral cancers and inflammatory disorders

Association of oral diseases and disorders with altered microRNA profiles is firmly recognized. These evidences support the potential use of microRNAs as therapeutic tools for diagnosis, prognosis, and treatment of various diseases. In this review, we highlight the association of altered microRNA signatures in oral cancers and oral inflammatory diseases. Advances in our ability to detect microRNAs in human sera and saliva further highlight their clinical value as potential biomarkers. We have discussed key mechanisms underlying microRNA dysregulation in pathological conditions. The use of microRNAs in diagnostics and their potential therapeutic value in the treatment of oral diseases are reviewed.

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

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

Expression deregulation of mir31 and CXCL12 in two types of oral precancers and cancer: importance in progression of precancer and cancer

Oral cancer generally progresses from precancerous lesions such as leukoplakia (LK), lichen planus (LP) and oral submucous fibrosis (OSMF). Since few of these precancers progress to cancers; it is worth to identify biological molecules that may play important roles in progression. Here, expression deregulation of 7 miRNAs (mir204, mir31, mir31*, mir133a, mir7, mir206 and mir1293) and their possible target genes in 23 cancers, 18 LK, 12 LP, 23 OSMF tissues compared to 20 healthy tissues was determined by qPCR method. Expression of mir7, mir31, mir31* and mir1293 was upregulated and that of mir133a, mir204 and mir206 was downregulated in cancer. Expression of most of these miRNAs was also upregulated in LK and LP tissues but not in OSMF. Expression deregulation of some of the target genes was also determined in cancer, LK and LP tissues. Significant upregulation of mir31 and downregulation of its target gene, CXCL12, in cancer, LK and LP tissues suggest their importance in progression of precancer to cancer. Expression upregulation of mir31 was also validated using GEO data sets. Although sample size is low, novelty of this work lies in studying expression deregulation of miRNAs and target genes in oral cancer and three types of precancerous lesions.

Genomewide miRNA profiling of oral lichenoid disorders and oral squamous cell carcinoma

OBJECTIVE

To dissect the aberrant microRNA profile of oral lichenoid disorders (OLD) by analyzing the larger set of OLD samples tested so far.

MATERIALS AND METHODS

MicroRNA expression profiles were assessed using TLDA card in 32 samples (16 OLD, 8 OSCC, and 8 control). The findings were validated using RT-qPCR in an independent cohort of 91 samples.

RESULTS

We identified 20 differentially expressed microRNAs in OLD, of which several are functionally related to cell proliferation, response to organic substances, or immune processes. Further validation of the top-ranked microRNAs revealed that they were all aberrantly expressed in OLD.

CONCLUSION

We have identified a new microRNA signature associated with OLD that may provide a meaningful basis for better understanding the physiopathology of the disease. In addition, we validated seven microRNAs whose expression was shown to be higher in OLD tissue in comparison with the control and OSCC tissues.

MicroRNAs-208b-3p, 204-5p, 129-2-3p and 3065-5p as predictive markers of oral leukoplakia that progress to cancer

Leukoplakia is the most common precursor lesion of oral squamous cell carcinoma (OSCC). Currently, the risk of progression to OSCC is assessed based on histopathologic examination alone. However, this method fails to identify the subset of microscopically innocuous leukoplakia that ultimately transforms to OSCC. The aim of this study was to determine if microRNAs (miRNAs) can be utilized to identify non- and low-grade dysplastic oral lesions at risk for cancer progression. A retrospective study of genome-wide miRNA expression level analyses was performed in the training cohort (n=20) using deep sequencing formalin-fixed paraffin embedded incisional biopsy tissues from patients with oral leukoplakic lesions diagnosed with non- or low-grade dysplasia and known clinical outcome. The promising miRNA candidates were then evaluated in the validation cohort (n=80) using quantitative real-time PCR (qRT-PCR). Four promising miRNAs-208b-3p, 204-5p, 129-2-3p and 3065-5p were identified. Combining these four miRNAs as a panel with age and histologic diagnosis (p<0.004), our final model had a predictive value for the area under the receiver operating characteristic (ROC) curve (AUC) of 0.792, sensitivity of 76.9% and specificity of 73.7% to accurately identify non- and low-grade dysplastic lesions at risk of cancer progression, which is a significant improvement over histopathologic examination alone (AUC of 0.645). While further investigation is needed, discovery of predictive markers that can accurately identify histologically innocuous oral lesions at high risk for progression to OSSC will significantly improve clinical outcome by means of early intervention.

Oral squamous cell carcinoma: microRNA expression profiling and integrative analyses for elucidation of tumourigenesis mechanism

Background

The advantages and utility of microRNAs (miRNAs) as diagnostic and prognostic cancer markers is at the vanguard in recent years. In this study, we attempted to identify and validate the differential expression of miRNAs in oral squamous cell carcinoma (OSCC), to correlate their expression with the clinico-pathological profile of tumours and to identify the signaling pathways through which the aberrantly expressed miRNAs effect tumourigenesis.

Methods

miRCURY LNA™ array with probes specific to 1168 miRNAs and TaqMan assays specific for 10 miRNAs was employed to evaluate and validate miRNA expression in a discovery cohort (n = 29) and validation cohort (n = 61) of primary OSCC tissue specimens, respectively. A computational pipeline with sequential integration of data from miRTarBase, CytoScape, UniProtKB and DIANA-miRPath was utilized to map the target genes of deregulated miRNAs and associated molecular pathways.

Results

Microarray profiling identified 46 miRNAs that were differentially expressed in OSCC. Unsupervised clustering demonstrated a high degree of molecular heterogeneity across the tumour samples as the clusters did not represent any of their clinico-pathological characteristics. The differential expression of 10 miRNAs were validated by RT-qPCR (let-7a, let-7d, let-7f and miR-16 were downregulated while miR-29b, miR-142-3p, miR-144, miR-203, and miR-223 were upregulated in OSCC; the expression of miR-1275 was variable in tumours, with high levels associated to regional lymph node invasion; additionally, miR-223 exhibited an association with advanced tumour stage/size). In silico analyses of the experimentally confirmed target genes of miRNAs revamp the relationship of upregulated miRNAs with tumour suppressor genes and of downregulated miRNAs with oncogenes. Further, the differentially expressed miRNAs may play a role by simultaneously activating genes of PI3K/Akt signaling on one hand and by repressing genes of p53 signaling pathway on the other.

Conclusions

The identified differentially expressed miRNAs and signaling pathways deregulated in OSCC have implications for the development of novel therapeutic strategies. To the best of our knowledge, this is the first report to show the association of miR-1275 with nodal invasion and the upregulation of miR-144 in OSCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0512-8) contains supplementary material, which is available to authorized users.

MicroRNAs in oral lichen planus and potential miRNA-mRNA pathogenesis with essential cytokines: a review

Oral lichen planus (OLP) is a potentially premalignant condition with unknown pathogenesis. Immune and inflammatory factors are thought to play important roles in the development of OLP, and cytokines, such as interferon (IFN)-γ and tumor necrosis factor (TNF)-α, can act as critical players in the immunopathogenesis of OLP. MicroRNAs (miRNAs) are closely correlated with cytokines in various inflammation-related diseases. In patients with OLP, miRNA-146a and miRNA-155 are increased in peripheral blood mononuclear cells, and numerous miRNAs have been shown to exhibit altered expression profiles in lesions. Although the microRNA-messenger RNA (miRNA-mRNA) network is thought to be involved in the development of OLP, in-depth studies are lacking. Here, we summarize current data on the mechanisms of action of miRNAs regulating typical cytokines in OLP, including interleukin (IL)-10, IL-17, IL-22, IFN-γ, and TNF-α, to study the genetic basis of the pathogenesis of OLP and to provide prospects of therapy.

microRNA-21 and microRNA-375 from oral cytology as biomarkers for oral tongue cancer detection

OBJECTIVE

We previously performed a meta-analysis of microRNA profiling studies on head and neck/oral cancer (HNOC), and identified 11 consistently dysregulated microRNAs in HNOC. Here, we evaluate the diagnostic values of these microRNAs in oral tongue squamous cell carcinoma (OTSCC) using oral cytology samples.

MATERIALS AND METHODS

The levels of 11 microRNAs were assessed in 39 oral cytology samples (19 OTSCC and 20 normal subjects), and 10 paired OTSCC and adjacent normal tissues. The predictive power of these microRNAs was analyzed by receiver operating characteristic curve (ROC) and random forest (RF) model. A classification and regression trees (CART) model was generated using miR-21 and miR-375, and further validated using both independent oral cytology validation sample set (14 OTSCC and 11 normal subjects) and tissue validation sample set (12 paired OTSCC and adjacent normal tissues).

RESULTS

Differential expression of miR-21, miR-100, miR-125b and miR-375 was validated in oral cytology training sample set. Based on the RF model, the combination of miR-21 and miR-375 was selected which provide best prediction of OTSCC. A CART model was constructed using miR-21 and miR-375, and was tested in both oral cytology and tissue validation sample sets. A sensitivity of 100% and specificity of 64% was achieved in distinguishing OTSCC from normal in the oral cytology validation set, and a sensitivity of 83% and specificity of 83% was achieved in the tissue validation set.

CONCLUSION

The utility of microRNA from oral cytology samples as biomarkers for OTSCC detection is successfully demonstrated in this study.

Similar Squamous Cell Carcinoma Epithelium microRNA Expression in Never Smokers and Ever Smokers

The incidence of oral tumors in patients who never used mutagenic agents such as tobacco is increasing. In an effort to better understand these tumors we studied microRNA (miRNA) expression in tumor epithelium of never tobacco users, tumor epithelium of ever tobacco users, and nonpathological control oral epithelium. A comparison of levels among 372 miRNAs in 12 never tobacco users with oral squamous cell carcinoma (OSCC) versus 10 healthy controls was made using the reverse transcription quantitative polymerase chain reaction. A similar analysis was done with 8 ever tobacco users with OSCC. These comparisons revealed miR-10b-5p, miR-196a-5p, and miR-31-5p as enriched in the tumor epithelium in OSCC of both never and ever tobacco users. Examination of The Cancer Genome Atlas (TCGA) project miRNA data on 305 OSCCs and 30 controls revealed 100% of those miRNAs enriched in never smoker OSCCs in this patient group were also enriched in ever smoker OSCCs. Nonsupervised clustering of TCGA OSCCs was suggestive of two or four subgroups of tumors based on miRNA levels with limited evidence for differences in tobacco exposure among the groups. Results from both patient groups together stress the importance of miR196a-5p in OSCC malignancy in both never and ever smokers, and emphasize the overall similarity of miRNA expression in OSCCs in these two risk groups. It implies that there may be great similarity in etiology of OSCC in never and ever smokers and that classifying OSCC based on tobacco exposure may not be helpful in the clinic.

MiR-221 increases osteosarcoma cell proliferation, invasion and migration partly through the downregulation of PTEN

Increasing evidence has demonstrated that microRNAs (miRNAs or miRs) are involved in cancer initiation and progression. Previous studies have indicated that miR-221 is one of the most consistently overexpressed miRNAs in multiple types of cancer. However, the role of miR-221 in osteosarcoma carcinogenesis and progression is not yet fully understood. Thus, the aim of the present study was to examine the expression of miR-221 in osteosarcoma and to determine the effects of miR-221 on the biological behavior of osteosarcoma cells. RT-qPCR revealed that the expression of miR-221 was significantly upregulated in the osteosarcoma tissues and osteosarcoma cell lines (p<0.05). In order to explore the role of miR-221 in osteosarcoma, the expression of miR-221 in the human osteosarcoma cell line MG‑63 was upregulated or downregulated by transfection with miR-221 mimic or miR-221 inhibitor, respectively. The results from RT-qPCR revealed that we had successfully generated MG‑63 cells in which miR-221 was either overexpressed or depleted. To investigate the effects of miR-221 on osteosarcoma cell proliferation, invasion and migration, a tetrazolium-based colorimetric assay, propidium iodide (PI) staining, a transwell migration assay and a wound healing assay were used in the present study. The results revealed that the proliferation, invasion and migration ability of the MG‑63 cells in which miR-221 was overexpressed was enhanced, and the proliferation, invasion and migration ability of the MG‑63 cells in which miR-221 was depleted was suppressed. The correlation between miR-221 and phosphatase and tensin homolog (PTEN) expression was investigated by RT-qPCR and western blot analysis. The results revealed that the downregulation of miR-221 significantly increased the expression of PTEN, whereas the upregulation of miR-221 significantly reduced the expression of PTEN. Taken together, our results suggest that miR-221 enhances the proliferation, invasion and migration ability of osteosarcoma cells partly by suppressing PTEN.