Oral swirl samples - a robust source of microRNA protected by extracellular vesicles

Expression of microRNA-21 in saliva and tumor tissue of patients with oral squamous cell carcinoma: a predictor of cervical lymph node metastasis

OBJECTIVE

Evaluation of diagnostic accuracy of microRNA-21 (miR-21) in saliva and tumor tissue for presurgical assessment of lymph node metastasis in patients with oral squamous cell carcinoma (OSCC).

STUDY DESIGN

Unstimulated whole saliva and tumor tissue was obtained from clinically suspected patients with OSCC. A total of 130 patients diagnosed with OSCC were included as study participants. The assessment of cervical lymph node metastasis was done before surgery using imaging scans and post surgically confirmed by histopathologic examination of excised lymph nodes. miR-21 expression was evaluated using real-time polymerase chain reaction. The data was statistically analyzed for correlation analysis, cutoff values, sensitivity, and specificity. The κ statistic was applied to assess the degree of agreement between the lymph node metastasis and miR-21 expression.

RESULTS

miR-21 expression showed a statistically significant correlation with cervical lymph node metastasis with a diagnostic accuracy of 65% to 71.54% in saliva and 69% to 81.54% in tumor tissue. Very good agreement was observed between tumor tissue miR-21-3p and cervical lymph node metastasis with a specificity of 80.60% and a sensitivity of 82.40%.

CONCLUSIONS

miR-21 expression in saliva and tumor tissue of patients with OSCC showed high diagnostic accuracy for assessment of cervical lymph node metastasis. It can be used as an alternative for assessment of cervical lymph node metastasis before surgery.

The utilization of saliva as an early diagnostic tool for oral cancer: microRNA as a biomarker

Recently, dentistry presents a preventive philosophy, seeking early diagnoses and minimally traumatic treatments for patients. Cancer is known for its aggressive nature, where its signals and symptoms may only appear in advanced stages of the disease, therefore, reducing the possibility of using atraumatic treatment options and patient survival. Saliva has in its composition substances which can be used as biomarkers for disease diagnoses, one of those being microRNA. microRNAs are a group of small RNA molecules with 18-24 nucleotides which have functions such as the degradation of oncogenes transcripted mRNA. The aim of this paper is to explore all theoretical possibilities that microRNA offers as an early diagnostic tool for oral cancer. Studies show that microRNA can be directly linked with cancer gene regulation. Because microRNA is more specific to tissues and diseases than mRNA, it holds the premise of being a feasible, non-invasive, and stable biomarker for early diagnosis of oral cancer. The fact that miRNA can be found in saliva makes it an extremely affordable and feasible option as a biomarker to be used. Since it is linked to regulating functions of cancer genes, it also brings hope that in the near future, it could be used as a reliable biomarker.

Non-invasive screening of a microRNA-based dysregulation signature in oral cancer and oral potentially malignant disorders

INTRODUCTION

We have previously shown that oral swirls are a robust source of microRNA protected by extracellular vesicles, potentially useful to detect oral squamous cell carcinoma (OSCC)-associated molecular aberration.

OBJECTIVES

To study a developed dysregulation score and risk classification algorithm based upon a panel of OSCC-associated microRNA in oral swirls from individuals with OSCC and oral potentially malignant disorders (OPMDs).

MATERIALS AND METHODS

An OSCC-associated panel of 5 microRNAs (miR-24; miR-21; miR-99a; let-7c; miR-100;) was quantified by qPCR in 190 individuals with and without mucosal abnormalities, including OSCC (n = 53) and OPMDs (n = 74). Each sample was analyzed using a developed dysregulation score (dSCORE) and risk classification algorithm, allocating a LOW- or HIGH-RISK score. The influence of demographic, systemic, oral health and mucosal disease factors on the developed test was analyzed.

RESULTS

MicroRNA for analysis can be predictably isolated from oral swirls sourced from individuals with a range of demographic, systemic and oral health findings. Utilizing the presence of HIGH-RISK identified OSCC patients with 86.8% sensitivity and 81.5% specificity. Older age and female gender were associated with higher dSCOREs and higher proportions of HIGH-RISK classification amongst individuals with no mucosal abnormalities. The dSCOREs for all subgroups of OPMDs were significantly different from the OSCC group.

CONCLUSION

This is the first comparison of microRNA sourced from oral swirls from individuals with OPMDs with individuals with and without OSCC. A HIGH-RISK dysregulation signature was found to be accurate in indicating the presence of OSCC and exampled to parallel malignant transformation.

Salivary Extracellular Vesicle-Associated exRNA as Cancer Biomarker

Extracellular vesicles (EVs) secreted in biological fluids contain several transcripts of the cell of origin, which may modify the functions and phenotype of proximal and distant cells. Cancer-derived EVs may promote a favorable microenvironment for cancer growth and invasion by acting on stroma and endothelial cells and may favor metastasis formation. The transcripts contained in cancer EVs may be exploited as biomarkers. Protein and extracellular RNA (exRNA) profiling in patient bio-fluids, such as blood and urine, was performed to identify molecular features with potential diagnostic and prognostic values. EVs are concentrated in saliva, and salivary EVs are particularly enriched in exRNAs. Several studies were focused on salivary EVs for the detection of biomarkers either of non-oral or oral cancers. The present paper provides an overview of the available studies on the diagnostic potential of exRNA profiling in salivary EVs.

Predicting the Presence of Oral Squamous Cell Carcinoma Using Commonly Dysregulated MicroRNA in Oral Swirls

Oral swirls are a noninvasive, rapidly collected source of salivary microRNA (miRNA) potentially useful in the early detection of disease states, particularly oral squamous cell carcinoma (OSCC). The aim of this study was to predict the presence of OSCC using a panel of OSCC-related dysregulated miRNA found in oral swirls, identified jointly in data from formalin-fixed paraffin-embedded (FFPE) and fresh-frozen specimens. Next-generation sequencing (NGS) was used to determine miRNA fold changes in FFPE OSCC specimens relative to histologically normal epithelium. These data were placed with NGS of fresh-frozen tissue data of The Cancer Genome Atlas database to select a panel of commonly dysregulated miRNA. This panel was then analyzed by RT-qPCR in RNA extracted from oral swirls collected from 30 patients with OSCC and 30 controls. Upregulation of miR-31 and miR-21 and downregulation of miR-99a, let-7c, miR-125b, and miR-100 were found between OSCC and controls in both FFPE and fresh-frozen samples. These miRNAs were studied in a training set of 15 OSCC versus 15 control oral swirls to develop a dysregulation score [AUC, 0.95; 95% confidence interval (CI), 0.88-1.03] and classification tree. A test cohort of 15 OSCC versus 15 control oral swirls yielded a dysregulation score AUC of 0.86 (95% CI, 0.79-1.00) with the classification tree identifying 100% (15/15) of OSCC and 67% (10/15) of controls. This study debuts the use of OSCC-associated miRNA, commonly dysregulated in both FFPE and frozen specimens, in oral swirls to indicate the presence of OSCC with high accuracy. Cancer Prev Res; 11(8); 491-502. ©2018 AACR.

Salivary extracellular vesicle-associated miRNAs as potential biomarkers in oral squamous cell carcinoma

BACKGROUND

Several studies in the past have investigated the expression of micro RNAs (miRNAs) in saliva as potential biomarkers. Since miRNAs associated with extracellular vesicles (EVs) are known to be protected from enzymatic degradation, we evaluated whether salivary EVs from patients with oral squamous cell carcinoma (OSCC) were enriched with specific subsets of miRNAs.

METHODS

OSCC patients and controls were matched with regards to age, gender and risk factors. Total RNA was extracted from salivary EVs and the differential expression of miRNAs was evaluated by qRT-PCR array and qRT-PCR. The discrimination power of up-regulated miRNAs as biomarkers in OSCC patients versus controls was evaluated by the Receiver Operating Characteristic (ROC) curves.

RESULTS

A preliminary qRT-PCR array was performed on samples from 5 OSCC patients and 5 healthy controls whereby a subset of miRNAs were identified that were differentially expressed. On the basis of these results, a cohort of additional 16 patients and 6 controls were analyzed to further confirm the miRNAs that were up-regulated or selectively expressed in the previous pilot study. The following miRNAs: miR-302b-3p and miR-517b-3p were expressed only in EVs from OSCC patients and miR-512-3p and miR-412-3p were up-regulated in salivary EVs from OSCC patients compared to controls with the ROC curve showing a good discrimination power for OSCC diagnosis. The Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway analysis suggested the possible involvement of the miRNAs identified in pathways activated in OSCC.

CONCLUSIONS

In this work, we suggest that salivary EVs isolated by a simple charge-based precipitation technique can be exploited as a non-invasive source of miRNAs for OSCC diagnosis. Moreover, we have identified a subset of miRNAs selectively enriched in EVs of OSCC patients that could be potential biomarkers.

Extracellular vesicles from oral squamous carcinoma cells display pro- and anti-angiogenic properties

BACKGROUND

A new intercellular communication mode established by neoplastic cells and tumor microenvironment components is based on extracellular vesicles (EVs). However, the biological effects of the EVs released by tumor cells on angiogenesis are not completely understood. Here, we aimed to understand the biological effects of EVs isolated from two cell lines of oral squamous cell carcinoma (OSCC) (SCC15 and HSC3) on endothelial cell tubulogenesis.

METHODS

OSCC-derived EVs were isolated with a polymer-based precipitation method, quantified using nanoparticle tracking analysis and verified for EV markers by dot blot. Functional assays were performed to assess the angiogenic potential of the OSCC-derived EVs.

RESULTS

The results showed that EVs derived from both cell lines displayed typical spherical-shaped morphology and expressed the EV markers CD63 and Annexin II. Although the average particle concentration and size were quite similar, SCC15-derived EVs promoted a pronounced tubular formation associated with significant migration and apoptosis rates of the endothelial cells, whereas EVs derived from HSC3 cells inhibited significantly endothelial cell tubulogenesis and proliferation.

CONCLUSION

The findings of this study reveal that EVs derived from different OSCC cell lines by a polymer-based precipitation method promote pro- or anti-angiogenic effects.