An immunohistochemical study of p53 expressions in oral submucous fibrosis

Computational analysis of phytocompounds in Centella asiatica for its antifibrotic and drug-likeness properties - Herb to drug study

Oral submucous fibrosis (OSMF) is a potentially malignant disorder with no permanent cure that affects the quality of life due to trismus. Computational pharmacology has accelerated the discovery of drug candidates for the treatment of incurable diseases. The present study aimed to screen the compounds of the miracle herb Centella asiatica with drug-likeness properties based on the absorption, distribution, metabolism, and excretion (ADME) properties. The pharmacological actions of these screened compounds against OSMF were identified by network pharmacology, gene ontology, pathway enrichment analysis, molecular docking, and simulation. Fifteen drug-like ligands were identified after virtual screening viz; asiatic acid, kaempferol, quercetin, luteolin, apigenin, bayogenin, gallic acid, isothankunic acid, madecassic acid, madasiatic acid, arjunolic acid, terminolic acid, catechin, epicatechin, and nobiletin. 850 potential targets were predicted for the ligands, which were analyzed against 354 proteins associated with OSMF. Compound pathway analysis and disease pathway analysis identified 53 common proteins. The GO enrichment analysis identified 472 biological process terms, 76 molecular function terms, and 44 cellular component terms. Pathway enrichment analysis predicted 142 KEGG pathways, 35 Biocarta pathways, and 236 Reactome pathways for the target proteins. The analysis revealed that the herb targets crucial events of fibrosis such as inflammation, oxidative stress, apoptosis, collagen deposition, and epithelial-mesenchymal transition. The common 53 proteins were used for protein-protein interaction (PPI) network analysis, which revealed 4 key proteins interacting with the phytocompounds viz; transforming growth factor-β1 (TGF-β1), mothers against decapentaplegic-3 (SMAD-3), mitogen-activated protein kinase-1 (MAPK-1) and proto-oncogene tyrosine-protein kinase (SRC). Molecular docking revealed that all ligands had a good binding affinity to the target proteins. Bayogenin had the highest binding affinity towards MAPK-1 (-9.7 kcal/mol), followed by isothankunic acid towards SRC protein (-9.3 kcal/mol). Madasiatic acid had the highest binding affinity to SMAD-3 (-7.6 kcal/mol) and TGF-β1 (-7.1 kcal/mol). Molecular dynamics simulation demonstrated stable ligand protein interactions of bayogenin and MAPK complex, isothankunic acid and SRC complex. This in silico study is the first to identify potential phytochemicals present in Centella asiatica and their target molecules, which might be responsible for reversing 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.

Senescent Fibroblast in Oral Submucous Fibrosis Aids in Disease Progression and Malignant Transformation

Aim

To study the role of senescent fibroblasts (SFs) and its secretory phenotypes promoting fibrosis and malignancy in oral submucous fibrosis (OSMF).

Material Methods

A total of 20 cases of OSMF and 20 normal oral mucosal tissues were taken for the study. The tissue sections were stained for IHC-immunohistochemistry with senescent cell marker p^16INK4a. The supernatant solution of the transport medium was studied for leached out senescent associated secretory proteins (SASP): matrix metalloproteinases 9 (MMP9), interleukins 6 (IL6), vascular endothelial growth factor (VEGF). Tissues were studied for malignant transformation with p53 and Ki67. Fibrosis in the OSMF was tested with lysyloxidase (LOX). The Statistical Package for the Social Sciences (SSPS) statistical software was used to analyze the data.

Results

IHC staining for p^16INK4ashowed positivity in the connective tissue of OSMF cases which was statistically significant. Antibody assay using enzyme-linked immunosorbent assay (ELISA) showed elevated levels of secretoproteins IL6, MMP9, VEGF in OSMF cases. LOX enzyme levels were also significantly increased in OSMF cases. Proliferative markers Ki67 and p53 were positive in IHC staining in the epithelium of OSMF.

Conclusion

This study confirms the presence of SF and its secreto phenotypes in OSMF and showed increased LOX expression which is implicated in fibrosis. These findings suggest that SF may contribute to fibrosis in OSMF. The study also confirms the malignant transformation of the overlying epithelium as shown by p53 and Ki67 positivity.

Clinicopathological Correlation of Cyclooxygenase 2 Expression in Oral Submucous Fibrosis: An Immunohistochemical Study

Background:

Oral submucous fibrosis (OSMF) has a high prevalence in Southeast Asia with increased malignant transformation rates. Numerous biomarkers are currently being investigated to predict the disease prognosis and for early detection of malignant changes.

Materials and Methods:

A prospective study was conducted comprising 40 subjects with clinically and biopsy-proven OSMF being included in the study as experimental group (n = 28) and patients with no tobacco/betel nut habit, who underwent surgical removal of third molar, being included as control group (n = 12). About 5-μm sections from formalin-fixed paraffin-embedded tissue blocks were obtained for immunohistochemical (IHC) study. The expression of cyclooxygenase 2 (COX 2) was evaluated in the experimental group and compared in morphologically normal oral epithelium. The intensity of stain was assessed at different levels of epithelium (basal, stratum spinosum, superficial level) and connective tissue.

Results:

Based on IHC expression of COX 2, all the patients of the control group were negative for COX 2, and among the OSMF group, 19 patients (67.9%) were positive and 9 patients (32.1%) were found to be negative for COX 2. The association of COX2 expression on comparison of controls with OSMF was found to be statistically significant (χ² =21.955; P = 0.000). On comparison of immune expression of COX 2 in different clinical stages based on functional staging, we found significant association of COX 2 expression with the stage of OSMF (χ² = 7.368; P = 0.025).

Conclusion:

The significant expression of COX 2 in different clinical stages of OSMF when compared with normal shows the role of COX 2 in the pathogenesis of OSMF and could serve as a potent biomarker for assessing the disease progression.