Circulating MicroRNA-21 Expression as a Novel Serum Biomarker for Oral Sub-Mucous Fibrosis and Oral Squamous Cell Carcinoma

Mechanisms and markers of malignant transformation of oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic premalignant disease associated with betel quid chewing. Epidemiological studies indicate that there are approximately 5 million individuals suffering from OSF worldwide, with a concerning malignancy transformation rate of up to 4.2 %. When OSF progresses to oral squamous cell carcinoma (OSCC), the 5-year survival rate for OSCC drops to below 60 %. Therefore, early screening and diagnosis are essential for both preventing and effectively treating OSF and its potential malignant transformation. Numerous studies have shown that the malignant transformation of OSF is associated with various factors, including epigenetic reprogramming, epithelial-mesenchymal transition, hypoxia, cell cycle changes, immune regulation disturbances, and oxidative damage. This review article focuses on the unraveling the potential mechanisms underlying the malignant transformation of OSF, as well as the abnormal expression of biomarkers throughout this transformative process, with the aim of aiding early screening for carcinogenic changes in OSF. Furthermore, we discuss the significance of utilizing blood and saliva components from patients with OSF, along with optical diagnostic techniques, in the early screening of OSF malignant transformation.

Identification of a serum-based microRNA signature that detects recurrent oral squamous cell carcinoma before it is clinically evident

BACKGROUND

Survival rates for oral squamous cell carcinoma (OSCC) have remained poor for decades, a fact largely attributable to late-stage diagnoses and high recurrence rates. We report analysis of serum miRNA expression in samples from patients with high-risk oral lesions (HRL, including OSCC/carcinoma in situ lesions) and healthy non-cancer controls, with the aim of non-invasively detecting primary or recurrent disease before it is clinically evident.

METHODS

Discovery, test, and validation sets were defined from a total of 468 serum samples (305 HRL and 163 control samples). Samples were analysed using multiple qRT-PCR platforms.

RESULTS

A two-miRNA classifier comprised of miR-125b-5p and miR-342-3p was defined following discovery and test analyses. Analysis in an independent validation cohort reported sensitivity and specificity of ~74% for this classifier. Significantly, when this classifier was applied to serial serum samples taken from patients both before treatment and during post-treatment surveillance, it identified recurrence an average of 15 months prior to clinical presentation.

CONCLUSIONS

These results indicate this serum miRNA classifier is effective as a simple, non-invasive monitoring tool for earlier detection of recurrent disease when lesions are typically smaller and amenable to a wider array of treatment options to improve survival.

Sensitive SERS detection of oral squamous cell carcinoma-related miRNAs in saliva via a gold nanohexagon array coupled with hybridization chain reaction amplification

In this work, a highly specific and sensitive method for the detection of dual miRNAs was successfully developed by a hybridization chain reaction (HCR) amplification coupled with surface-enhanced Raman scattering (SERS) on Au-Ag hollow nanoparticles (Au-Ag HNPs) and a gold nanohexagon (AuNH) array. Two Raman reporter-labelled and hairpin DNA-modified Au-Ag HNPs acted as SERS probes (Au-Ag HNPs@4-MBA@HP_1-1, Au-Ag HNPs@4-MBA@HP_2-1, Au-Ag HNPs@DTNB@HP_1-2, and Au-Ag HNPs@DTNB@HP_2-2), and the hairpin DNA-modified AuNH array acted as the capture substrate. The HCR process could be triggered by the presence of target miRNAs, and long DNA hybridization chains on the substrate were formed by self-assembly rapidly, causing significant signal enhancement. Using the mentioned strategy, a low detection limit (LOD) of 6.51 aM for miR-31 and 6.52 aM for miR-21 in human saliva were obtained, showing the biosensor's remarkable sensitivity. The proposed biosensor also displays a significant specificity in detecting target miRNAs by introducing different interfering factors. This method has been successfully applied to detect and identify miR-21 and miR-31 in saliva from oral squamous cell carcinoma (OSCC) patients and healthy subjects. The results were consistent with those of the traditional test method in detecting target miRNAs, which confirmed the good accuracy of our method. Hence, the new assay method has great potential to be a valuable platform for detecting miRNAs in the early diagnosis of OSCC.

Liquid biopsy in the assessment of microRNAs in oral squamous cell carcinoma: A systematic review

Background

The identification of non-invasive biomarkers from biological fluids collected by liquid biopsy provides new horizons for individualized therapeutic strategies and improves clinical decision-making in OSCC patients. Circulating microRNAs have emerged as biomarkers that may reflect not only the existence of cancer, but also the dynamic, malignant potential, and drug resistance of tumors. The aim of the systematic review is to evaluate and summarize the results of the published studies regarding the use of microRNAs as biomarkers for OSCC.

Material and Methods

A literature search was conducted on PubMed, Scopus, Web of Science, and Cochrane databases till November 2020. A total of 34 studies met the inclusion criteria and were therefore subjected to quality assessment. Each study was subjected to data extraction including; patient characteristics, type of fluid sample (whole blood, plasma, serum, or saliva), molecular analysis method, specific dysregulated microRNA, and microRNA expression pattern.

Results

The analysis showed that 57 microRNAs of liquid biopsy samples of four different fluids (whole blood, serum, plasma, and saliva) were analyzed. The prognostic and therapeutic significance of these microRNAs were suggested by several studies; where 41 microRNAs were upregulated while 16 were downregulated.

Conclusions

Scientific evidence supports the interest in the use of microRNAs in the diagnosis and prognosis in OSCC patients; however, further studies in a larger cohort of patients are mandatory to introduce liquid biopsy in the routine clinical practice for the OSCC management. Key words:Biomarkers, liquid biopsy, microRNA, oral squamous cell carcinoma, systematic review.

Expression of Salivary miRNA 21 in Oral Submucous Fibrosis (OSMF): An Observational Study

Objective:

To observe the expression patterns of salivary mRNA 21 in different stages and grades of OSMF and also in habitual areca nut chewers without OSMF.

Subjects and Methods

The study consisted of a total of 185 samples, where 61 patients had chewing habits (chewing gutkha and other forms of areca nut) and had OSMF (Group 1). 61 patients had chewing habits but did not have OSMF (Group 2), and 63 were normal healthy patients (control group) without any chewing habits (Group 3). Unstimulated saliva samples were collected from patients following the standard operating procedures. miRNA 21 was isolated and purified from saliva samples using the miRNeasy Mini Kit, Qiagen. The primers for miRNA relative quantification analysis were designed using the Primer Express software of Applied Biosystems. Quantification of all the samples was carried out using SYBR chemistry in an Applied Biosystems Real-Time PCR.

Results

There was no statistically significant difference between the demographic characteristics of patients. There was a statistically significant difference between the expressions of miRNA 21 amongst the three groups noted in Kruskal Wallis test. (<0.001*) A post hoc test was perfomed to confirm the statistical difference between patients within all three groups. There was no statistically significant difference noted between the OSMF group and patients with chewing habits group (G1 vs. G2 p: 0.10), but there was a significant difference when compared with normal patients. (G1 vs. G3 p: <0.001*) and (G2 vs. G3 <0.001*)

Conclusion

This study concludes that miRNA 21 is overexpressed in OSMF and chewing habit patients. But the expression levels were not significantly associated with the severity of the disease process. A long term and large scale studies are required to assess its application as a diagnostic profibrotic marker in OSMF.

MicroRNAs in Transforming Growth Factor-Beta Signaling Pathway Associated With Fibrosis Involving Different Systems of the Human Body

Fibrosis, a major cause of morbidity and mortality, is a histopathological manifestation of many chronic inflammatory diseases affecting different systems of the human body. Two types of transforming growth factor beta (TGF-β) signaling pathways regulate fibrosis: the canonical TGF-β signaling pathway, represented by SMAD-2 and SMAD-3, and the noncanonical pathway, which functions without SMAD-2/3 participation and currently includes TGF-β/mitogen-activated protein kinases, TGF-β/SMAD-1/5, TGF-β/phosphatidylinositol-3-kinase/Akt, TGF-β/Janus kinase/signal transducer and activator of transcription protein-3, and TGF-β/rho-associated coiled-coil containing kinase signaling pathways. MicroRNA (miRNA), a type of non-coding single-stranded small RNA, comprises approximately 22 nucleotides encoded by endogenous genes, which can regulate physiological and pathological processes in fibrotic diseases, particularly affecting organs such as the liver, the kidney, the lungs, and the heart. The aim of this review is to introduce the characteristics of the canonical and non-canonical TGF-β signaling pathways and to classify miRNAs with regulatory effects on these two pathways based on the influenced organ. Further, we aim to summarize the limitations of the current research of the mechanisms of fibrosis, provide insights into possible future research directions, and propose therapeutic options for fibrosis.

[Prognostic value of plasma miR-1290 expression in patients with oral squamous cell carcinoma]

OBJECTIVE

To investigate the prognostic value of plasma miR-1290 in patients with oral squamous cell carcinoma (OSCC).

METHODS

Seventy patients with OSCC admitted to Danzhou People's Hospital from January 2014 to December 2018 were included in this study. Real-time fluorescence quantitative polymerase chain reaction (PCR) was used to detect the expression of miR-1290 in these patients. The optimal cut-off value of plasma miR-1290 expression was determined by the ROC curve method, and patients with OSCC were divided into the high (n=31) and low (n=39) miR-1290-expressing groups. The clinicopathological features of the two groups were compared, and survival curves were drawn using the Kaplan-Meier method. Risk factors affecting the poor prognosis of patients were analyzed using univariate and multivariate COX regression models.

RESULTS

The expression level of plasma miR-1290 in the OSCC group was significantly lower than that in the control group (0.65±0.14 vs. 2.06±0.90; t=13.912, P<0.001). The low expression of plasma miR-1290 appeared to be related to the clinical stage, differentiation degree, tumor diameter, and lymph node metastasis of OSCC (P<0.05). Survival analysis showed that the overall survival rate and the progression-free survival rate of the low-miR-1290 group were significantly lower than that of the high-miR-1290 group (P<0.01). Multivariate COX regression analysis showed that clinical stage, lymph node metastasis, and plasma miR-1290<1.14 were independent risk factors for the poor prognosis of patients with OSCC (P<0.05).

CONCLUSIONS

The expression level of plasma miR-1290 in patients with OSCC significantly decreased, and the low expression of miR-1290 is related to the short survival time of OSCC patients. Thus, miR-1290 may be a potential marker predicting the poor prognosis of OSCC.

Cell-Free microRNAs as Potential Oral Cancer Biomarkers: From Diagnosis to Therapy

Oral cavity cancer is the most frequent malignancy of the head and neck. Unfortunately, despite educational interventions for prevention and early diagnosis, oral cancer patients are often diagnosed in advanced stages associated with poor prognosis and life expectancy. Therefore, there is an urgent need to find noninvasive biomarkers to improve early detection of this tumor. Liquid biopsy has emerged as a valuable tool in medical oncology which provides new horizons for improving clinical decision making. Notably, cell-free microRNAs (miRNAs), a class of short non-coding RNAs, are emerging as novel noninvasive cancer biomarkers. Here, we provide an overview of the potential clinical application of cell-free miRNAs as diagnostic, prognostic, and therapeutic biomarkers in oral cancer.

Epigenetic Modifications in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common human malignancy in the world, with high mortality and poor prognosis for patients. Among the risk factors are tobacco and alcohol intake, human papilloma virus, and also genetic and epigenetic modifications. Many studies show that epigenetic events play an important role in HNSCC development and progression, including DNA methylation, chromatin remodeling, histone posttranslational covalent modifications, and effects of non-coding RNA. Epigenetic modifications may influence silencing of tumor suppressor genes by promoter hypermethylation, regulate transcription by microRNAs and changes in chromatin structure, or induce genome instability through hypomethylation. Moreover, getting to better understand aberrant patterns of methylation may provide biomarkers for early detection and diagnosis, while knowledge about target genes of microRNAs may improve the therapy of HNSCC and extend overall survival. The aim of this review is to present recent studies which demonstrate the role of epigenetic regulation in the development of HNSCC.

miRNA-21 promotes cell proliferation and invasion via VHL/PI3K/AKT in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the main kind of thyroid carcinoma, most of which are diagnosed in women. MiR-21 has been reported to be upregulated in multiple cancers to effect tumor growth. However, the role of miR-21 in PTC development remains unclear. In this present study, miR-21 and VHL expressions in PTC tissues and cells were evaluated by RT-qPCR and/or western blot. MTT assay and transwell assay were employed to assess cell proliferative and invasive abilities, respectively. Luciferase reporter assay was carried out to identify the target of miR-21and explore its roles in PTC. MiR-21 was upregulated in PTC tissues and cells. Ectopic of miR-21 expression promoted cell proliferative and invasive abilities, while knockdown miR-21 suppressed these in TPC-1 and BCPAP cells. Overexpression of miR-21 predicted poor prognosis in PTC. What is more, luciferase reporter assays showed miR-21 can directly target VHL in PTC cells. Knockdown of miR-21 expression inhibited TPC-1 and BCPAP cell invasion-mediated EMT and proliferation through the PI3K/AKT pathway. In addition, VHL reverses partial function of miR-21 on PTC cell proliferation and invasion. MiR-21 can inhibit cell proliferation and invasion by regulated VHL in PTC cells. The newly identified miR-21/VHL axis might provide a novel insight into the pathogenesis and therapy of PTC.

Investigation of the Prognostic Role of Carbonic Anhydrase 9 (CAIX) of the Cellular mRNA/Protein Level or Soluble CAIX Protein in Patients with Oral Squamous Cell Carcinoma

Carbonic anhydrase 9 (CAIX) is an important protein that stabilizes the extracellular pH value and is transcriptionally regulated by hypoxia-inducible factor 1 (HIF1), but more stable than HIF1α. Here we show a comparative study that examines the prognostic value of CA9 mRNA, CAIX protein of tumor cells and secreted CAIX protein for oral squamous cell carcinoma (OSCC) patients. Tumor samples from 72 OSCC patients and 24 samples of normal tissue were analyzed for CA9 mRNA levels. A total of 158 OSCC samples were stained for CAIX by immunohistochemistry and 89 blood serum samples were analyzed by ELISA for soluble CAIX protein content. Survival analyses were performed by Kaplan–Meier and Cox’s regression analysis to estimate the prognostic effect of CA9/CAIX in OSCC patients. The CA9 mRNA and CAIX protein levels of tumor cells correlated with each other, but not with those of the secreted CAIX protein level of the blood of patients. ROC curves showed a significant (p < 0.001) higher mRNA-level of CA9 in OSCC samples than in adjacent normal tissue. Cox’s regression analysis revealed an increased risk (i) of death for patients with a high CA9 mRNA level (RR = 2.2; p = 0.02), (ii) of locoregional recurrence (RR = 3.2; p = 0.036) at higher CA9 mRNA levels and (iii) of death at high CAIX protein level in their tumors (RR = 1.7; p = 0.066) and especially for patients with advanced T4-tumors (RR = 2.0; p = 0.04). However, the secreted CAIX protein level was only as a trend associated with prognosis in OSCC (RR = 2.2; p = 0.066). CA9/CAIX is an independent prognostic factor for OSCC patients and therefore a potential therapeutic target.