Identification of Gene and MicroRNA Signatures for Oral Cancer Developed from Oral Leukoplakia

Molecular and Therapeutic Roles of Non-Coding RNAs in Oral Cancer-A Review

Oral cancer (OC) is among the most common malignancies in the world. Despite advances in therapy, the worst-case scenario for OC remains metastasis, with a 50% survival rate. Therefore, it is critical to comprehend the pathophysiology of the condition and to create diagnostic and treatment plans for OC. The development of high-throughput genome sequencing has revealed that over 90% of the human genome encodes non-coding transcripts, or transcripts that do not code for any proteins. This paper describes the function of these different kinds of non-coding RNAs (ncRNAs) in OC as well as their intriguing therapeutic potential. The onset and development of OC, as well as treatment resistance, are linked to dysregulated ncRNA expression. These ncRNAs' potentially significant roles in diagnosis and prognosis have been suggested by their differing expression in blood or saliva. We have outlined every promising feature of ncRNAs in the treatment of OC in this study.

Correlation of H3K9ac and H4K12ac With Cell Proliferation Marker Ki-67 in Oral Leukoplakia: An Immunohistochemical Study

This study aimed to analyze the immunohistochemical expression of H3K9ac and H4K12ac in oral leukoplakia (OL) and its association with cell proliferation marker Ki-67 and clinicopathologic data. Paraffin-embedded, formalin-fixed tissue samples from 50 OLs and 15 fragments of the normal oral mucosa (NOM) were submitted to immunohistochemical assay using the streptavidin-biotin-peroxidase method. Quantitative analysis of the antigen-antibody reaction was performed by obtaining integrated optical density (IOD) and the percentage of positive nuclei (PPN) with ImageJ software. OL samples presented higher PPN ( P =0.02) and lower IOD values ( P =0.007) for H4K12ac in comparison to NOM. The area under the receiver operating characteristic curve for PPN and IOD values of H4K12ac immunostaining were 0.70 ( P =0.02) and 0.73 ( P =0.007), respectively. No differences were found between OL and NOM for H3K9ac. Cell proliferation marker Ki-67 had a positive correlation with PPN ( P <0.0001) and IOD ( P =0.0007) for H3K9ac expression and with IOD values ( P =0.002) for H4K12ac expression. The present findings suggest that alterations in the acetylation pattern of H4K12 occur in the early stages of oral carcinogenesis and that both H3K9ac and H4K12ac might have a role in the regulation of epithelial cell proliferation of OL.

The Connection between MicroRNAs and Oral Cancer Pathogenesis: Emerging Biomarkers in Oral Cancer Management

Oral cancer is a common human malignancy that still maintains an elevated mortality rate despite scientific progress. Tumorigenesis is driven by altered gene expression patterns of proto-oncogenes and tumor-suppressor genes. MicroRNAs, a class of short non-coding RNAs involved in gene regulation, seem to play important roles in oral cancer development, progression, and tumor microenvironment modulation. As properties of microRNAs render them stable in diverse liquid biopsies, together with their differential expression signature in cancer cells, these features place microRNAs at the top of promising biomarkers for diagnostic and prognostic values. In this review, we highlight eight expression levels and functions of the most relevant microRNAs involved in oral cancer development, progression, and microenvironment sustainability. Furthermore, we emphasize the potential of using these small RNA species as non-invasive biomarkers for the early detection of oral cancerous lesions. Conclusively, we highlight the perspectives and limitations of microRNAs as novel diagnostic tools, as well as therapeutic models.

The relevance of miRNAs as promising biomarkers in lip cancer

OBJECTIVES

This study aimed to analyze the expression of miR-181b, miR-21, miR-31, and miR-345 in actinic cheilitis with and without epithelial dysplasia and lower lip squamous cell carcinomas, and to verify if the deregulated expression of these miRNAs would be indicative of malignant transformation.

MATERIALS AND METHODS

The sample was selected from formalin-fixed paraffin-embedded tissues of 19 actinic cheilitis without epithelial dysplasia, 32 actinic cheilitis with epithelial dysplasia, 42 lower lip squamous cell carcinomas, and 10 nonaltered oral mucosa of the lip. The microRNA (miR, miRNA) expression was quantified by real-time RT-PCR and the expression of the selected miRNAs among the groups of actinic cheilitis and lower lip cancer was compared by chi-square.

RESULTS

A higher expression of miR-181b, miR-31, and miR-345 was found in actinic cheilitis without epithelial dysplasia in comparison to that in actinic cheilitis with epithelial dysplasia and with lower lip cancer. There were no differences in miR-21 expression between actinic cheilitis and lower lip cancer. Hierarchical clustering analysis showed a tendency for a downregulation of miR-181b, miR-21, miR-31, and miR-345 in most patients with lower lip cancers.

CONCLUSIONS

The upregulation of miR-181b, miR-31, and miR-345 expression in actinic cheilitis without epithelial dysplasia and the decrease in the expression of these miRNAs in actinic cheilitis with epithelial dysplasia and in lower lip cancer are potential biomarkers of malignant progression.

CLINICAL RELEVANCE

This miRNA signature can help to identify actinic cheilitis with potential to progress to lip cancer.

BCAR1 promotes proliferation and cell growth in lung adenocarcinoma via upregulation of POLR2A

BACKGROUND

This study was designed to investigate the effects of a novel carcinogenetic molecule, p130cas (breast cancer antiestrogen resistance protein 1 or BCAR1) on proliferation and cell growth in lung adenocarcinoma. The study also aimed to identify the possible underlying signal networks of BCAR1.

METHODS

First, we evaluated proliferation, cell colony formation, apoptosis, and cell cycle after BCAR1 was knocked out (KO) using CRISPR-Cas9 technology in H1975 and H1299 human lung adenocarcinoma cells. Subsequently, BCAR1 was upregulated in 293T cells and immunoprecipitation-mass spectrometry (IP-MS) was used with bioinformatics analysis to screen for potential networks of BCAR1 interacting proteins. Ultimately, we validated the correlated expressions of BCAR1 and a selected hub gene, RNA polymerase II subunit A (POLR2A), in 54 lung adenocarcinoma tissues, as well as in H1975 and H1299 cells.

RESULTS

Cell proliferation of H1975 and H1299 was significantly inhibited following BCAR1-KO. Colony formation of H1975 cells was also significantly decreased following BCAR1-KO. IP-MS demonstrated 419 potential proteins that may interact with BCAR1. Among them, 68 genes were significantly positively correlated to BCAR1 expression, as verified by TCGA. Six hub genes were revealed by PPI String. High expression of POLR2A, MAPK3, MOV10, and XAB2 predicted poor prognosis in lung adenocarcinoma, as verified by the K-M plotter database. POLR2A and MAPK3 are involved in both catalytic activity and transferase activity. POLR2A and BCAR1 were significantly increased in lung cancer tissues as compared with matched normal tissues. High expression of POLR2A was significantly positively correlated to BCAR1 overexpression and predicted poor prognosis in 54 lung cancer cases. POLR2A expression was significantly decreased following BCAR1-KO in H1975 and H1299 cells.

CONCLUSIONS

BCAR1 promotes proliferation and cell growth, probably via upregulation of POLR2A and subsequent enhancement of catalytic and transferase activities. However, additional robust studies are required to elucidate the mechanisms involved.

Gene expression changes associated with malignant transformation of oral potentially malignant disorders

BACKGROUND

A large number of oral squamous cell carcinomas (OSCCs) are believed to be preceded by oral potentially malignant disorders (OPMD) that have an increased likelihood of malignant transformation compared to clinically normal mucosa. This study was performed to identify differentially expressed genes between OPMDs that underwent malignant transformation (MT) and those that did not, termed "non-transforming" (NT) cases.

METHODS

Total RNA was extracted from formalin-fixed paraffin-embedded tissue biopsies of 20 OPMD cases with known clinical outcomes (10 MT vs. 10 NT). Samples were assessed for quantity, quality and integrity of RNA prior to sequencing. Analysis for differential gene expression between MT and NT was performed using statistical packages in R. Genes were considered to be significantly differentially expressed if the False Discovery Rate corrected P-value was < 0.05.

RESULTS

RNA yield was variable but RNA purity was good (A260/A280 > 1.90). Analysis of RNA-Sequencing outputs revealed 41 genes (34 protein-coding; 7 non-coding) that were significantly differentially expressed between MT and NT cases. The log2 fold change for the statistically significant differentially expressed genes ranged from -2.63 to 2.48, with 23 protein-coding genes being downregulated and 11 protein-coding genes being upregulated in MT cases compared to NT cases.

CONCLUSION

Several candidate genes that may play a role in malignant transformation of OPMD have been identified. Experiments to validate these candidates are underway. It is anticipated that this work will contribute to better understanding of the etiopathogenesis of OPMD and development of novel biomarkers.

CD47 as a potential prognostic marker for oral leukoplakia and oral squamous cell carcinoma

Cluster of differentiation (CD)47, which acts as a negative indicator for phagocytic cells, is overexpressed on the surface of multiple human solid tumor cell types. Avoiding phagocytosis by CD47 is required for the progression of solid tumors. The present study investigated the expression of CD47 in oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC), and preliminarily explored the impact of CD47 on the proliferation of OSCC cells. A total of 56 tissue samples, including 36 cases of OLK, 10 cases of OSCC and 10 cases of normal oral mucosa (NOM) were selected to detect the expression of CD47 by immunohistochemistry. For subgroup analysis, OLK samples were divided into OLK with low-risk dysplasia (LR-OLK) and OLK with high-risk dysplasia (HR-OLK). The subcellular localization of CD47 was determined by immunofluorescence in three OSCC cell lines (Tca8113, SCC-9 and Cal-27). The effect of CD47 antibody on the proliferation of the Cal-27 cell line was analyzed using the Cell Counting kit-8 assay. CD47 expression in OLK and OSCC lesions was significantly higher than in NOM (P<0.05). Compared with LR-OLK, the expression of CD47 in HR-OLK and OSCC cells was upregulated (P=0.0327 and P=0.0048, respectively). CD47 was highly expressed in OSCC cell lines (Tca8113, Cal-27 and SCC-9) and weakly expressed in normal oral keratinocytes. The proliferation of Cal-27 cells was inhibited by CD47 antibody in a concentration and time-dependent manner. CD47 may be a reliable biomarker for predicting the progression of oral precancer and cancer, and it may serve as an important molecular target for designing a novel therapy for oral cancer.

Toward the use of precision medicine for the treatment of head and neck squamous cell carcinoma

Precision medicine is a new strategy that aims at preventing and treating human diseases by focusing on individual variations in people's genes, environment and lifestyle. Precision medicine has been used for cancer diagnosis and treatment and shows evident clinical efficacy. Rapid developments in molecular biology, genetics and sequencing technologies, as well as computational technology, has enabled the establishment of "big data", such as the Human Genome Project, which provides a basis for precision medicine. Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with a high incidence rate and low survival rate. Current therapies are often aggressive and carry considerable side effects. Much research now indicates that precision medicine can be used for HNSCC and may achieve improved results. From this perspective, we present an overview of the current status, potential strategies, and challenges of precision medicine in HNSCC. We focus on targeted therapy based on cell the surface signaling receptors epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) and human epidermal growth factor receptor-2 (HER2), and on the PI3K/AKT/mTOR, JAK/STAT3 and RAS/RAF/MEK/ERK cellular signaling pathways. Gene therapy for the treatment of HNSCC is also discussed.

Meta-Analysis of miRNAs and Their Involvement as Biomarkers in Oral Cancers

Oral Squamous Cell Carcinoma (OSCC) is one of the most common cancers worldwide. Recent studies have highlighted the role of miRNA in disease pathology, indicating its potential use as an early diagnostic marker. Dysregulated expression of miRNAs is known to affect cell growth, and these may function as tumor suppressors or oncogenes in various cancers. The main objective of this study was to characterize the extracellular miRNAs involved in oral cancer (OC) that can potentially be used as biomarkers of OC. A total of 318 miRNAs involved in oral carcinoma were shortlisted. Differentially expressed genes (DEGs) of oral carcinoma from reported experiments were identified. Common genes between lists of DEGs of OC of each miRNA were identified. These common genes are the targets of specific miRNA, which may be used as biomarkers of OC. A list of significant biomarkers for cancer was generated like CDH2 and CDK7, and functional enrichment analysis identified the role of miRNAs in major pathways like cell adhesion molecules pathway affected by cancer. We observed that at least 25 genes like ABCF3, ALDH2, CD163L1, and so forth are regulated by a maximum number of miRNAs; thereby, they can be used as biomarkers of OC.

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.

MicroRNA and target gene expression based clustering of oral cancer, precancer and normal tissues

PURPOSE

Development of oral cancer is usually preceded by precancerous lesion. Despite histopathological diagnosis, development of disease specific biomarkers continues to be a promising field of study. Expression of miRNAs and their target genes was studied in oral cancer and two types of precancer lesions to look for disease specific gene expression patterns.

METHODS

Expression of miR-26a, miR-29a, miR-34b and miR-423 and their 11 target genes were determined in 20 oral leukoplakia, 20 lichen planus and 20 cancer tissues with respect to 20 normal tissues using qPCR assay. Expression data were, then, used for cluster analysis of normal as well as disease tissues.

RESULTS

Expression of miR-26a and miR-29a was significantly down regulated in leukoplakia and cancer tissues but up regulated in lichen planus tissues. Expression of target genes such as, ADAMTS7, ATP1B1, COL4A2, CPEB3, CDK6, DNMT3a and PI3KR1 was significantly down regulated in at least two of three disease types with respect to normal tissues. Negative correlations between expression levels of miRNAs and their targets were observed in normal tissues but not in disease tissues implying altered miRNA-target interaction in disease state. Specific expression profile of miRNAs and target genes formed separate clusters of normal, lichen planus and cancer tissues.

CONCLUSION

Our results suggest that alterations in expression of selected miRNAs and target genes may play important roles in development of precancer to cancer. Expression profiles of miRNA and target genes may be useful to differentiate cancer and lichen planus from normal tissues, thereby bolstering their role in diagnostics.

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.