Evaluation of immunohistochemical expression of epithelial- mesenchymal transition markers E-cadherin, Twist and Snail in oral submucous fibrosis and their possible association with malignant transformation

Oral submucous fibrosis: pathogenesis and therapeutic approaches

Oral submucous fibrosis (OSF), characterized by excessive deposition of extracellular matrix (ECM) that causes oral mucosal tissue sclerosis, and even cancer transformation, is a chronic, progressive fibrosis disease. However, despite some advancements in recent years, no targeted antifibrotic strategies for OSF have been approved; likely because the complicated mechanisms that initiate and drive fibrosis remain to be determined. In this review, we briefly introduce the epidemiology and etiology of OSF. Then, we highlight how cell-intrinsic changes in significant structural cells can drive fibrotic response by regulating biological behaviors, secretion function, and activation of ECM-producing myofibroblasts. In addition, we also discuss the role of innate and adaptive immune cells and how they contribute to the pathogenesis of OSF. Finally, we summarize strategies to interrupt key mechanisms that cause OSF, including modulation of the ECM, inhibition of inflammation, improvement of vascular disturbance. This review will provide potential routes for developing novel anti-OSF therapeutics.

Recent Advance on Biological Activity and Toxicity of Arecoline in Edible Areca (Betel) Nut: A Review

Areca nut (Areca catechu L. AN), which is the dried, mature seed of the palm species Areca catechu L., is consumed by over 600 million individuals, predominantly in South Asia, East Africa, and certain regions of the tropical Pacific. The International Agency for Research on Cancer (IARC) has classified it as a species carcinogenic to humans and designated it as a Group 1 human carcinogen. Arecoline, which has attracted attention for its therapeutic potential in the treatment of mental illness and the relief of gastrointestinal disorders, is the main active alkaloid in the areca nut. However, in 2020, the IARC said that arecoline might be a "probable human carcinogen". Arecoline can cause various types of cellular damage, primarily leading to the destruction of cell morphology, reduced survival rates, abnormal physiological functions, and even cell apoptosis. The research on its toxic mechanisms includes several aspects, such as increased levels of reactive oxygen species, autophagy, epigenetic dysregulation, and immune dysfunction, but these research findings are scattered and lack systematic integration. This article summarizes the effect mechanisms of arecoline on the oral cavity, neurological and cardiovascular systems, and other organs, as well as embryogenesis, and provides detailed and valuable insights for the clinical practice and targeted therapy of arecoline.

Enhanced ZEB 1 stromal expression is a marker for epithelial mesenchymal transition in oral submucous fibrosis

Introduction

Oral submucous fibrosis is a progressive oral mucosal condition that is characterized by inflammation and persistent fibrosis. Epithelial Mesenchymal Transition is a crucial molecular event that contributes to tumor progression and fibrosis, with ZEB 1 and its effect on E-cadherin expression being key molecules in the process. Thera are no tissue level studies of these molecules in oral submucous fibrosis.

Objective

To evaluate the immunohistochemical expression of epithelial mesenchymal transition markers E-cadherin and ZEB1 in oral submucous fibrosis.

Methodology

A total of 30 cases of Oral submucous fibrosis (15 Early OSMF and 15 Advanced OSMF) classified based on the histopathological features were included in the study. Immunohistochemistry was done using two markers i.e. E-cadherin and ZEB1. The difference in the expression of E-Cadherin and ZEB1 among histo-pathological grades of OSMF was done by Mann-Whitney U test.

Results

A slight reduction in the E-cadherin expression was noted in Oral submucous fibrosis but marked enhanced expression of ZEB1 was seen in the connective tissue of OSMF.

Conclusion

An increase in intensity and percentage of positivity of ZEB 1 expression in connective tissue was observed in advanced cases as compared to early OSMF. This can be attributed to role of ZEB1 in mediating EMT via transdifferentiation of fibroblast into myofibroblast and thus predispose to fibrosis in OSMF.

Molecular pathways of oral submucous fibrosis and its progression to malignancy

OBJECTIVE

The review aims to comprehend various factors engaged in the alteration of molecular events resulting in Oral submucous fibrosis (OSMF) and its malignant transformation.

DESIGN

Literature pertinent to pathways involved in OSMF were explored in databases such as PubMed, Scopus and Google Scholar. The relevant literature was reviewed and critically appraised in this narrative review.

RESULTS

Areca nut components influence myriad of cellular molecules such as cytokines, growth factors, myofibroblasts, non-coding RNAs and alter their expression. These aberrantly expressed molecules drive the progression of OSMF from localized inflammation to fibrosis of buccal mucosa. The oral tissue suffers from oxidative stress, hypoxia, autophagy, aberration of cell cycle and DNA damage. Apoptosis of epithelial layer results in its atrophy facilitating deeper penetration of areca nut elements. With the advance of disease, epithelial-mesenchymal transition eventuates and promotes dysplasia. The jeopardized expression of various cellular molecules, suppressed apoptosis, along with increased genetic alterations and neovascularization favors the malignant transformation.

CONCLUSION

OSMF is a progressive disorder with complex mechanism of pathogenesis initiated by inflammation of oral mucosa. Continuous habit of areca nut chewing and the resulting insult to the tissues prevents healing process and is destined to debilitating disease which affects the quality of life with a higher probability of progression to malignancy.

Is Epithelial-Mesenchymal Transition a New Roadway in the Pathogenesis of Oral Submucous Fibrosis: A Comprehensive Review

Epithelial-mesenchymal transition (EMT) collectively refers to a series of episodes that reshape polarized, intact epithelial cells into discrete motile cells that can conquer the extracellular matrix (ECM). It performs a pivotal role in embryonic development, wound healing, and tissue repair. Surprisingly, the exact mechanism can also lead to the onset of malignancy and organ fibrosis contributing to scar formation and loss of function. transforming growth factor signaling, WNT signaling, Notch signaling, Hedgehog signaling, and receptor tyrosine kinase signaling, as well as non-transcriptional changes in response to extracellular cues, such as growth factors and cytokines, hypoxia, and contact with the surrounding ECM, are responsible for the initiation of EMT.

Although the pathogenesis of oral submucous fibrosis (OSMF) is multifactorial, compelling evidence suggests that it results from collagen deregulation. EMT is one of the spotlight events in the pathogenesis of OSMF, with myofibroblasts and keratinocytes being the victim cells. EMT is an essential step in both physiological and pathological events. The importance of EMT in the malignant development of OSMF and the inflammatory reaction preceding fibrosis implies a new upcoming area of research.

This review aims to focus on the EMT events that function as a double-edged sword between wound healing and fibrosis and further discuss the mechanisms along with the molecular pathways that direct changes in gene expression essential for the same in the oral cavity. As OSMF involves a risk of malignant transformation, understanding the cellular and molecular events will open more avenues for therapeutic breakthroughs targeting EMT.

Integrated Proteomics Based on 2D Gel Electrophoresis and Mass Spectrometry with Validations: Identification of a Biomarker Compendium for Oral Submucous Fibrosis—An Indian Study

Oral Submucous Fibrosis (OSMF) is a chronic debilitating disease more frequently found in the South East Asian population. This disease poses a public health priority, as it is grouped under oral potentially malignant disorders, with malignant transformation rates of around 7 to 13%. Hence, early identification of high-risk OSMF patients is of the utmost importance to prevent malignant transformation. Proteomic expression profiling is a promising method for identifying differentially expressed proteins for disease prognosis and risk stratification in OSMF. In this study, overexpressed proteins in OSMF, OSMF transformed into oral squamous cell carcinoma (OSCC) and normal tissues were evaluated by proteomic analysis using two-dimensional electrophoresis (2DE) and mass spectrometry, which revealed 23 upregulated proteins. Validation was done using immunohistochemistry for three secretory proteins, namely 14-3-3ε (n = 130), carbonic anhydrase 1 (CA 1) (n = 125) and heat shock protein 70 (HSP 70) (n = 117), which showed significant overexpression in OSMF, OSCC compared to normal. The present study is the first of its kind in India to the best of our knowledge, assessing the altered expression of proteins in OSMF and OSMF which has undergone malignant transformation, obtaining a better knowledge of the molecular pathways involved in the disease progression. The current study shows that the biomarkers studied can be potentially useful for risk stratification of OSMF to OSCC serving as novel targets for therapeutic intervention. Clinical validation of the targets can further pave way for precision medicine to improve the quality of life in OSMF patients.