Association of Oral Submucous Fibrosis Risk with GSTM1 and GSTT1 Gene Polymorphisms.

OBJECTIVE: To determine the association of GSTM1 and GSTT1 polymorphisms with oral submucous fibrosis (OSF). STUDY DESIGN: A case-control study. Place and Duration of the Study: Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore and Oral and Maxillofacial Surgery Department, de Montmorency, College of Dentistry/ Punjab Dental Hospital, Lahore, Pakistan, from 1st April 2019 to 31st April 2020. METHODOLOGY: OSF patients were diagnosed with different clinical staging of mouth opening by Vernier caliper with the help of a professional dentist in the Department of Oral and Maxillofacial, de Montmorency, College of Dentistry, Lahore. One hundred and eight blood samples of OSF patients and 108 samples of normal controls were collected. Genomic DNA was obtained from whole-blood extraction. Multiplex PCR amplification using GSTM1, GSTT1, and ß -Globin gene primers was performed. RESULTS: GSTM1 and GSTT1 null genotypes frequencies were found in 43.5% (47/108) and 13.9% (15/108) of controls, whereas 54.6% (59/108) and 25.9% (28/108) of OSF patients, respectively. OSF patients had a greater frequency rate of GSTM1 and GSTT1 null genotypes than controls [OR 1.56, 95% CI 0.91-2.67 (p=0.13)] and [OR 2.17, 95% CI 1.08-4.34 (p=0.04)], respectively. The GSTT1 genotype was found statistically significant with OSF (p=0.05), and risk was also determined. The cumulative effect of null genotypes of GSTM1/GSTT1 did not show any association with the controls and in OSF patients. Proportions of active and null alleles of the patient group were; 86.1%/13.9%; and in control, it was 92.6%/7.4% (OR = 2.01; CI: 0.82-4.97; p=0.18), respectively. CONCLUSION: The study determined a statistically significant association of GSTT1 gene polymorphism with OSF. KEY WORDS: Oral submucous fibrosis, GSTM1, GSTT1, Gene polymorphisms, Genetic risk.

Salivary transforming growth factor beta in oral submucous fibrosis: A diagnostic and predictive marker.

CONTEXT: Growth factors and cytokines like transforming growth factor beta (TGF-ß) play a key role in the pathogenesis of oral submucous fibrosis. AIMS: To elucidate the role of Salivary TGF-ß isoforms as a predictive and diagnostic marker for oral submucous fibrosis. SETTINGS AND DESIGN: A total of 30 OSMF and 10 control patients were included in this study, and their clinic-epidemiological data was recorded. METHODOLOGY: The expression of TGF-ß genes-TGF-ß1, TGF-ß2, TGF-ß3-was studied by a real-time polymerase chain reaction in tissue and saliva. Patients were given medicinal intervention for 12 weeks along with jaw-opening exercises. Expression of salivary TGF-ß genes was studied at 12 weeks. STATISTICAL ANALYSIS USED: SPSS software version 20. RESULT: Expression of salivary TGF beta isoforms in OSMF was more than in the control group. There was an increase in salivary TGF-ß1, ß2, ß3 expressions with increasing clinical grades of OSMF and advancing the stage of the disease. Expression of all the TGF beta isoforms was decreased after treatment with statistically significant results. Statistically significant correlations were found between the mean difference of TGF-ß1 and the mean difference between mouth opening and tongue protrusion. CONCLUSION: Salivary TGF-ß isoforms may be used in diagnosis, risk assessment, and screening of the entire population at risk of OSMF after its clinical validation. However, adequate sample size and segmental assessment of the expression of TGF-ß isoforms are needed for further evaluation.

Aberrantly downregulated FENDRR by arecoline elevates ROS and myofibroblast activation via mitigating the miR-214/MFN2 axis.

Long non-coding RNA FENDRR possesses both anti-fibrotic and anti-cancer properties, but its significance in the development of premalignant oral submucous fibrosis (OSF) remains unclear. Here, we showed that FENDRR was downregulated in OSF specimens and fibrotic buccal mucosal fibroblasts (fBMFs), and overexpression of FENDRR mitigated various myofibroblasts hallmarks, and vice versa. In the course of investigating the mechanism underlying the implication of FENDRR in myofibroblast transdifferentiation, we found that FENDRR can directly bind to miR-214 and exhibit its suppressive effect on myofibroblast activation via titrating miR-214. Moreover, we showed that mitofusin 2 (MFN2), a protein that is crucial to the fusion of mitochondria, was a direct target of miR-214. Our data suggested that FENDRR was positively correlated with MFN2 and MFN2 was required for the inhibitory property of FENDRR pertaining to myofibroblast phenotypes. Additionally, our results showed that the FENDRR/miR-214 axis participated in the arecoline-induced reactive oxygen species (ROS) accumulation and myofibroblast transdifferentiation. Building on these results, we concluded that the aberrant downregulation of FENDRR in OSF may be associated with chronic exposure to arecoline, leading to upregulation of ROS and myofibroblast activation via the miR-214-mediated suppression of MFN2.

[Oral squamous cell carcinoma in the background of oral submucous fibrosis - a systematic review]. / Skvamozno-kletochnaya kartsinoma polosti rta na fone podslizistogo fibroza polosti rta - sistematicheskii obzor.

Oral squamous cell carcinoma (OSCC) in the background of oral submucous fibrosis (OSMF) is one of the most common presentations of oral cancer among Asian population. OSCC arising in the background of OSMF (OSCC with OSMF) has been a topic of interest among researchers recently and a few studies have considered this to be a distinct clinicopathological entity. This systematic review analyses the demographic and clinicopathological variations of OSCC with OSMF from conventional OSCC to evaluate the distinctiveness of OSCC with OSMF. A comprehensive search from PubMed, Google scholar and manual search were carried out and 4 articles were retrieved and analysed systematically. Out of the total 377 OSCC with OSMF cases and 542 conventional OSCC, males were found to be predominantly affected (82.7% and 73.6%). 47% of the OSCC with OSMF cases were well differentiated squamous cell carcinomas as against 33.4% in conventional OSCC. Lymph node metastases were seen predominantly in conventional OSCC (49.1%) than OSCC with OSMF cases (40.7%). OSCC with OSMF were more prevalent in males and showed better tumour differentiation and lesser lymph node metastasis. Even though the present results inculpate OSCC with OSMF as a distinct clinicopathological entity, there is a dire need for thorough investigation.

Spatial Transcriptomic and Metabolomic Landscapes of Oral Submucous Fibrosis-Derived Oral Squamous Cell Carcinoma and its Tumor Microenvironment.

In South and Southeast Asia, the habit of chewing betel nuts is prevalent, which leads to oral submucous fibrosis (OSF). OSF is a well-established precancerous lesion, and a portion of OSF cases eventually progress to oral squamous cell carcinoma (OSCC). However, the specific molecular mechanisms underlying the malignant transformation of OSCC from OSF are poorly understood. In this study, the leading-edge techniques of Spatial Transcriptomics (ST) and Spatial Metabolomics (SM) are integrated to obtain spatial location information of cancer cells, fibroblasts, and immune cells, as well as the transcriptomic and metabolomic landscapes in OSF-derived OSCC tissues. This work reveals for the first time that some OSF-derived OSCC cells undergo partial epithelial-mesenchymal transition (pEMT) within the in situ carcinoma (ISC) region, eventually acquiring fibroblast-like phenotypes and participating in collagen deposition. Complex interactions among epithelial cells, fibroblasts, and immune cells in the tumor microenvironment are demonstrated. Most importantly, significant metabolic reprogramming in OSF-derived OSCC, including abnormal polyamine metabolism, potentially playing a pivotal role in promoting tumorigenesis and immune evasion is discovered. The ST and SM data in this study shed new light on deciphering the mechanisms of OSF-derived OSCC. The work also offers invaluable clues for the prevention and treatment of OSCC.

Exosomes Derived from Human Adipose Mesenchymal Stem Cells Inhibits Fibrosis and Treats Oral Submucous Fibrosis via the miR-181a-5p/Smad2 Axis.

BACKGROUND: Oral submucous fibrosis (OSF) is a chronic disease with carcinogenic tendency that poses a non-negligible threat to human health. Exosomes derived from human adipose mesenchymal stem cells (ADSC-Exo) reduces visceral and cutaneous fibroses, but their role in OSF has received little attention. The aim of this study was to investigate the effects of ADSC-Exo on OSF and elucidate the mechanism. METHODS: In brief, ADSCs were extracted from adipose tissues and subjected to flow cytometry and induction culture. Fibroblasts were isolated from human buccal mucosa and subjected to immunofluorescence. Myofibroblasts were obtained from fibroblasts induced by arecoline and identified. Immunofluorescence assay confirmed that myofibroblasts could take up ADSC-Exo. The effects of ADSC-Exo on the proliferative and migratory capacities of myofibroblasts were examined using the Cell Counting Kit-8 and scratch assay. Real-time quantitative polymerase chain reaction (qPCR) was performed to evaluate mothers against decapentaplegic homolog 2 (Smad2), Smad3, Smad7, collagen type 1 (Col1), Col3, alpha smooth muscle actin (α-SMA), fibronectin, and vimentin. Western blotting was performed to detect phospho (p)-Smad2, Smad2, p-Smad2/3, Smad2/3, Smad7, Col1, Col3, α-SMA, fibronectin, and vimentin. Furthermore, the dual-luciferase reporter assay was performed to prove that miR-181a-5p in ADSC-Exo directly inhibited the expression of Smad2 mRNA to regulate the transforming growth factor beta (TGF-ß) pathway. We also performed qPCR and western blotting to verify the results. RESULTS: ADSC-Exo could promote the proliferation and migration of myofibroblasts, reduce the expressions of p-smad2, Smad2, p-smad2/3, Smad2/3, Col1, αSMA, fibronectin, and vimentin and elevated the levels of Smad7 and Col3. In addition, miR-181a-5p was highly expressed in ADSC-Exo and bound to the 3'-untranslated region of Smad2. ADSC-Exo enriched with miR-181a-5p reduced collagen production in myofibroblasts and modulated the TGF-ß pathway. CONCLUSIONS: ADSC-Exo promoted the proliferative and migratory capacities of myofibroblasts and inhibited collagen deposition and trans-differentiation of myofibroblasts in vitro. miR-181a-5p in exosomes targets Smad2 to regulate the TGF-ß pathway in myofibroblasts. ADSC-Exo perform antifibrotic actions through the miR-181a-5p/Smad2 axis and may be a promising clinical treatment for OSF.

Gene mutation analysis of oral submucous fibrosis cancerization in Hainan Island.

Objective: The sequencing panel composed of 61 target genes was used to explore the related mutation genes of oral squamous cell carcinoma (OSCC) and oral submucous fibrosis (OSF) cancerization, so as to provide a theoretical basis for the early diagnosis of oral submucous fibrosis cancerization, find the most important mutations in OSF cancerization, and more targeted prevention of OSF cancerization. Methods: A total of 74 clinically diagnosed samples were included, including 36 cases of OSCC and 38 cases of OSF cancer patients. DNA was extracted, and targeted gene panel sequencing technology was used to analyze the gene frequency of pathogenic mutation sites in clinical samples. Results: Gene panel sequencing analysis showed that there were 69 mutations in 18 genes in OSCC and OSF cancerous specimens. The results of gene panel sequencing were screened, and 18 mutant genes were finally screened out and their mutation frequencies in the samples were analyzed. According to the frequency of gene mutations from high to low, they were TP53, FLT4, PIK3CA, CDKN2A, FGFR4, HRAS, BRCA1, PTPN11, NF1, KMT2A, RB1, PTEN, MSH2, MLH1, KMT2D, FLCN, BRCA2, APC. The mutation frequency of FLT4 gene was significantly higher than that of OSCC group (P < 0.05). Conclusion: FLT4 gene may be related to OSF cancerization and is expected to be an early diagnostic biomarker for OSF cancerization.

Isolation of Cells with Morphological and Spatial Information from Oral Submucous Fibrosis Samples by Laser Capture Microdissection.

Oral submucous fibrosis (OSF) is a common type of potentially malignant disorder in the oral cavity. The atrophy of epithelium and fibrosis of the lamina propria and the submucosa are often found on histopathological slides. Epithelial dysplasia, epithelial atrophy, and senescent fibroblasts have been proposed to be associated with the malignant transformation of OSF. However, because of the heterogeneity of potentially malignant oral disorders and oral squamous cell carcinoma, it is difficult to identify the specific molecular mechanisms of malignant transformation in OSF. Here, we present a method to obtain a small number of epithelial or mesenchymal cells carrying morphological data and spatial information by laser capture microdissection on formalin-fixed paraffin-embedded tissue slides. Using a microscope, we can precisely capture microscale (~500 cells) dysplastic or atrophic epithelial tissue and fibrotic subepithelial tissue. The extracted cells can be evaluated by genome or transcriptome sequencing to acquire genomic and transcriptomic data with morphological and spatial information. This approach removes the heterogeneity of bulk OSF tissue sequencing and the interference caused by cells in non-lesioned areas, allowing for precise spatial-omics analysis of OSF tissue.

α-Mangostin Inhibits the Activation of Myofibroblasts via Downregulation of Linc-ROR-Mediated TGFB1/Smad Signaling.

Oral submucous fibrosis (OSF) is a premalignant disorder and persistent activation of myofibroblasts is implicated in this pathological progression. Increasing attention has been addressed towards non-coding RNA-regulated myofibroblasts activities and the effects of phytochemicals on non-coding RNA modulation are of great importance. In the present study, we examined the anti-fibrosis property of α-mangostin, a xanthone isolated from the pericarp of mangosteen. We found that α-mangostin exhibited inhibitory potency in myofibroblast activities and expression of fibrosis markers at the concentrations that caused neglectable damage to normal cells. Apart from the downregulation of TGF-ß1/Smad2 signaling, we found that α-mangostin attenuated the expression of long non-coding RNA LincROR as well. Our results demonstrated that the effects of α-mangostin on myofibroblast activation were reverted when LincROR was overexpressed. Additionally, we showed the expression of LincROR in OSF specimens was elevated and silencing of LincROR successfully attenuated myofibroblast characteristics and TGF-ß1/Smad2 activation. Taken together, these findings indicated that the anti-fibrosis effects of α-mangostin merit consideration and may be due to the attenuation of LincROR.

Low-dose arecoline regulates distinct core signaling pathways in oral submucous fibrosis and oral squamous cell carcinoma.

BACKGROUND: Betel nut chewing plays a role in the pathogenesis of oral submucous fibrosis (OSF) and oral squamous cell carcinoma (OSCC). As the major active ingredient of the betel nut, the effect of arecoline and its underlying mechanism to OSF and OSCC pathogenesis remain unclear. METHODS: Next-generation sequencing-based transcriptome and dRRBS analysis were performed on OSF and OSCC cells under low-dose arecoline exposure. Functional analyses were performed to compare the different roles of arecoline during OSF and OSCC pathogenesis, and key genes were identified. RESULTS: In this study, we identified that low-dose arecoline promoted cell proliferation of both NFs and OSCC cells via the acceleration of cell cycle progression, while high-dose arecoline was cytotoxic to both NFs and OSCC cells. We performed for the first time the transcriptome and methylome landscapes of NFs and OSCC cells under low-dose arecoline exposure. We found distinct transcriptome and methylome profiles mediated by low-dose arecoline in OSF and OSCC cells, as well as specific genes and signaling pathways associated with metabolic disorders induced by low-dose arecoline exposure. Additionally, low-dose arecoline displayed different functions at different stages, participating in the modulation of the extracellular matrix via Wnt signaling in NFs and epigenetic regulation in OSCC cells. After exposure to low-dose arecoline, the node roles of FMOD in NFs and histone gene clusters in OSCC cells were found. Meanwhile, some key methylated genes induced by arecoline were also identified, like PTPRM and FOXD3 in NFs, SALL3 and IRF8 in OSCC cells, indicating early molecular events mediated by arecoline during OSF and OSCC pathogenesis. CONCLUSIONS: This study elucidated the contribution of low-dose arecoline to OSF and OSCC pathogenesis and identified key molecular events that could be targeted for further functional studies and their potential as biomarkers.

IRF4 as a novel target involved in malignant transformation of oral submucous fibrosis into oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) in the context of oral submucous fibrosis (OSF) has a high incidence owing to undefined pathogenesis. Identifying key genes and exploring the underlying molecular mechanisms involved in the conversion of OSF into OSCC are in urgent need. Differentially expressed genes (DEGs) between OSCC and OSF were dug from GEO databases and a total of 170 DEGs were acquired. Functional association of DEGs were analyzed by GO and KEGG. Protein-protein interactions (PPIs) analysis was carried out and candidate biomarkers were identified by Gene co-expression analysis and Cox analyses. Hub genes were confirmed by qRT-PCR in tissues and cell lines, of which we found that IRF4 mRNA was successively up-regulated from Normal to OSF and then to OSCC and associated with immune infiltrating levels. In addition, Immunohistochemical (IHC) and Immunofluorescence (IF) assays were conducted to validate the consistent upregulation of IRF4 and the oncogene role of IRF4 in OSF and OSCC at translation level. IRF4 may be indicative biomarker in transformation of OSF into OSCC. High IRF4 expression contribute to increased immune infiltration of OSCC and may provide a novel diagnostic marker for OSCC patients translated from OSF.

XIST/let-7i/HMGA1 axis maintains myofibroblasts activities in oral submucous fibrosis.

Long non-coding RNA XIST promotes the development of various types of head and neck cancers, but its role in the progression of precancerous oral submucous fibrosis (OSF) has not been determined yet. As such, we aimed to examine whether XIST implicates in the regulation of myofibroblast activation. Our results showed that the expression of XIST was upregulated in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs), and the silencing of XIST downregulated several myofibroblasts features. We demonstrated that elevation of let-7i after inhibition of XIST may lead to reduced myofibroblast activation. On the contrary, overexpression of high mobility group AT-Hook 1 (HMGA1) following the suppression of let-7i may result in enhanced myofibroblast activities. Moreover, we showed that the suppressive effect of silencing of XIST on myofibroblasts hallmarks was reversed by let-7i inhibition or HMGA1 overexpression, suggesting the pro-fibrotic property of XIST was mediated by downregulation of let-7i and upregulation of HMGA1. These findings revealed that myofibroblast activation of fBMFs may attribute to the alteration of the XIST/let-7i/HMGA1 axis. Therapeutic approaches to target this axis may serve as a promising direction to ameliorate the malignant progression of OSF.

Bioinformatics analysis of miRNA and its associated genes to identify potential biomarkers of oral submucous fibrosis and oral malignancy.

BACKGROUND: MicroRNAs are a group of non-coding RNA that controls the gene expression. The interaction between miRNA and mRNA is thought to be dynamic. Oral cancer "The cancer of mouth" is quite prevailing in developing countries. miRNA has been found associated with oral cancer targeting tumor growth, cell proliferation, metastasis, invasion. The significant association of miRNA with genes could be used as a remarkable tool for diagnosis as well as prognostic analysis of oral cancer. AIM: The aim of the present study is to evaluate common upregulated and downregulated miRNAs in oral submucous fibrosis (OSMF) and oral malignancy (OM) patients that can be used as diagnostic biomarkers, and to find out their interactions with target genes to establish associated networks in cancer pathways. METHODS AND RESULTS: Using miRDeep2 and DESeq analysis, the upregulated and downregulated miRNA in OSMF (Oral Submucous Fibrosis) and OM (Oral Malignancies) samples were compared to GEO (Gene Expression Omnibus) control dataset. There were 50 common downregulated miRNAs and 13 common upregulated miRNAs in OSMF and OM samples. miRNet analysis of common upregulated miRNA and common downregulated miRNA identified 1295 and 5954 genes, respectively connected with cancer pathways. From analysis of Hub genes, HRAS, STAT3, TP53, MYC, PTEN, CTNNB1, CCND1, JUN, VEGFA, KRAS were found associated with downregulated miRNA and VEGFA, TP53, MDM2, PTEN, MYC, ERBB2, CDKN1A, HSP90AA1, CCND1, AKTI were found associated with upregulated miRNA. The gene enrichment analysis of these hub genes were associated with cell communication, metabolic process, cell proliferation, and cellular component organization. Hub Genes linked with upregulated miRNA had an enrichment ratio of 11.828, whereas hub genes linked with downregulated miRNA had an enrichment ratio of 45.912. CONCLUSION: We identified common deregulated miRNAs between OSMF and OM patients, which were further analyzed to find out associations with the genes correlated to cancer pathways. The hub genes identified in this study were found to have a significant impact on tumor growth and carcinogenesis. Also, the enrichment of these genes has revealed that the genes are associated with cellular communication, metabolic processes and various biological regulation. These deregulated miRNAs can be used to make a panel of biomarkers to diagnose oral cancer from blood even before its onset.

Association of MICA gene Exon-5 polymorphism in oral submucous fibrosis.

OBJECTIVE: The present study was conducted to explore the allele frequencies of MICA gene Exon-5 transmembrane and to measure the circulatory MICA levels in various histologic grades of patients with oral submucous fibrosis (OSF) compared to healthy individuals. STUDY DESIGN: We enrolled a total of 595 patients for this cross-sectional study and divided them into 2 groups: healthy controls (n = 320) and patients with OSF (n = 275). Further, patients with OSF were subdivided based on their histologic gradings. The genomic DNA was extracted followed by a polymerase chain reaction and genotyping using the ABI Prism DNA Sequencer (ThermoFisher Scientific, Inc., Waltham, MA, USA). RESULTS: Our study showed that the A5 allele of the MICA gene in the Exon-5 region conferred significant risk for patients with OSF. With reference to the histologic gradings of OSF, we found that the MICA gene conferred statistically significant risk among patients with grade III OSF. On the other hand, the A8 allele of MICA gene in the Exon-5 region conferred significant protection among the overall OSF cohort and in the grade III of histologic grade. Finally, the circulatory human MICA levels were found to have a stepwise increase from grade I toward grade III in patients with OSF. CONCLUSION: Our results suggested that the A5 allele in MICA might confer risk for the progression of OSF among the South Indian ethnic population.

CC group of chemokines and associated gene expression of transcription factors: Deciphering immuno-pathogenetic aspect of oral submucous fibrosis.

BACKGROUND: Oral submucous fibrosis (OSMF) is a chronic disease with significantly increasing malignant transformation rate. To date the pathogenesis of OSMF has been considered to be associated with areca nut constituents and their action on fibroblasts. However, fibrosis is also associated with immunological factors such as chemokines. In-depth analysis of such factors is the need of the hour in OSMF to better understand the pathogenesis so that effective therapeutic strategies can be developed in the future. MATERIALS AND METHOD: Clinically diagnosed cases of OSMF (n=21) and healthy individuals (n=10) were enrolled in the present study. Chemokines such as CCL2, CCL3, CCL4, CCL5, CCL11, CCL17, CCL28, CXCL1, CXCL5, CXCL8, CXCL9, CXCL10, and CXCL11 were assessed using the chemokine bead array in conjunction with the flow cytometry, along with real-time PCR (RT-PCR). The transcription factors CREB, NF-κB and NFAT5 were also studied for their expressions. The analysis of pg/ml (picogram/milliliter) values was done by using LEGENDplex™ Data Analysis Software. RESULTS: The results obtained demonstrated early phase transient increase in CXCL-11, CCL20, CXCL9, CCL3, CCL2, CXCL10 and CXCL8. However, the expression of CCL3, CXCL10 and CXCL8 was higher in the late stage as compared to the early stage. The relative gene expression of CREB, NF-κB, NFAT5 were upregulated in the late stage of OSMF when compared to normal. CONCLUSION: Distinctive sets of chemokine expression during the early and late stages of OSMF suggest a unique pattern of disease progression playing an important role in the pathogenesis.

Comprehensive analysis of microRNAs and their target genes in oral submucous fibrosis.

The objective of the study is to understand the role of experimentally validated microRNAs (miRNAs) contributing to the acquisition of oncogenic phenotype in oral submucous fibrosis (OSF) by computational analysis. A comprehensive review was carried out to corroborate and summarize altered miRNA expression in OSF by retrieving relevant publications querying MEDLINE, Web of Science, Embase, and Scopus. The association between the miRNA-mRNA was performed using miRTarBase 8.0. The visualization of the miRNA-mRNA interaction was plotted using Cytoscape. MIENTURNET was used for the pathway analysis. Enrichment analysis was carried out for elucidating the hierarchical functions of miRNAs related to the acquisition of biological processes involved in the development of cancer. Thirteen miRNAs (hsa-miR-499a, hsa-miR-200b, hsa-miR-200c, hsa-miR-1246, hsa-miR-31, hsa-miR-10b, hsa-miR-21, hsa-miR-203, hsa-miR-455, hsa-miR-760, hsa-miR-623, hsa-miR-610, and hsa-miR-509-3-5p) were found to be deregulated in OSF. A total of 371 experimentally validated genes were shown to be interacting with the OSF-associated miRNAs. The targets of antifibrotic and profibrotic miRNAs were enriched in the cancer-related pathways. Dysregulated miRNA and its target genes illustrate the physiological role of miRNAs in fibrosis. Understanding the miRNA-mediated fibrotic signaling and targetting the specific miRNA-target gene interaction might provide relevant cues to ameliorate the fibrotic disease.

Global and promoter specific hypermethylation of tumor suppressor genes P16, SOCS1, and SHP1 in oral squamous cell carcinoma and oral submucous fibrosis.

ABSTRACTS: Aberrant methylation pattern leads to altered gene expression, that is, involved in the transformation of various cancers, including oral squamous cell carcinoma (OSCC). In the present study, an attempt has been made to examine the association of global and promoter-specific methylation of tumor suppressor genes in patients with OSCC and oral submucous fibrosis (OSMF). Promoter-specific methylation of tumor suppressor genes P16, SOCS1, and SHP1 had been studied earlier for their aberrant methylation patterns in other cancers; however, these studies were mainly conducted in-vitro or in animal models, and as such, only a few studies are available on human samples. In the present study evaluation of promoter-specific methylation of genes P16, SOCS1, and SHP1 in 76 patients' blood and tissue samples was done and compared with methylation of 35 healthy control samples using qPCR. Further, these samples were analyzed for global methylation patterns using ELISA. The results have shown a significant decreasing trend of promoter methylation (OSCC > OSMF > Controls); the methylation indices (MI) were significantly higher in OSCC than in the controls. The median MI of three genes for OSCC were P16MI (0.96), SHP1MI (0.79), and SOCS1 (0.80). Similarly, median MIs for OSMF were P16MI (0.18), SHP1 MI (0.19), and SOCS1 MI (0.5) against controls with MI (0) for each of the three genes. The global methylation %mC values were 1.9, 0.5, and 0.1, respectively. The values of MI and %mC were found to correlate with various risk factors such as tobacco, smoking, and alcohol consumption, which are positively involved in OSMF pathogenesis followed by oral cancer progression. Further, the methylation trend in tissue was reflected in blood samples, proving a window for methylation load to be used as a lesser invasive biomarker. The sensitivity and specificity of methylation load were also found reasonable. Therefore, the current study suggests that there may be a role of global and promoter-specific methylation load in the transition of OSMF to OSCC.

Comparative Somatic Variant Analysis of a Rare Case with Concurrent Oral Leukoplakia and Oral Submucosal Fibrosis.

Oral leukoplakia (OL) and oral submucosal fibrosis (OSMF) are precancerous conditions with common etiologies but with different risks for oral cancer (OC) progression. In rare cases, both conditions occur in the same patient and provide an opportunity for understanding the common and distinctive variants upon exposure of genetically identical normal cells to the same carcinogen(s). We performed exome sequencing of a patient with OL (hyperplasia, but no dysplasia) and OSMF (grade II) in the opposite cheeks using blood DNA as the reference genome. The overall somatic variant burden was higher in OSMF than OL, but opposite in the case of copy number alterations. OL-specific variants were enriched in genes associated with DNA repair, cell division/cell cycle checkpoint pathways, whereas in OSMF, extracellular matrix-receptor interaction was mainly affected. The proportions of variants in cancer driver genes and cancer driver mutations were similar in both cases indicating no difference in the potential risk associated with the two conditions at the stages sampled. Future studies on rare cases similar to the one described in this report will help in understanding the molecular basis of differences associated with OL and OSMF and shared processes accompanying OC progression.

Identification of a BRAF/PA28γ/MEK1 signaling axis and its role in epithelial-mesenchymal transition in oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a chronic and insidious oral potentially malignant disorder associated with a 4-17% risk of oral squamous cell carcinoma (OSCC). Our previous study found that proteasomal activator 28 gamma (PA28γ) is frequently overexpressed in oral squamous cell carcinoma and negatively correlated with poor patient prognosis. However, the role of PA28γ in the occurrence and development of OSF remains unclear. Here, we screened PA28γ-related genes and investigated their function in OSF. We demonstrated that the expression of PA28γ was positively associated with MEK1 and gradually elevated from normal to progressive stages of OSF tissue. Arecoline, a pathogenic component of OSF, could upregulate the protein levels of PA28γ and phosphorylated MEK1 and contribute to epithelial to mesenchymal transition (EMT) in epithelial cells. Notably, PA28γ could interact with MEK1 and upregulate its phosphorylation level. Furthermore, arecoline upregulated BRAF, which can interact with PA28γ and upregulate its protein level. Additionally, BRAF, PA28γ, and MEK1 could form protein complexes and then enhance the MEK1/ERK signaling pathways. The concrete mechanism of the protein stability of PA28γ is that BRAF mediates its degradation by inhibiting its ubiquitination. These findings underscore the instrumental role of PA28γ in the BRAF/MEK1 pathway and enhanced EMT through MEK1/ERK activation in OSF.

Low LINC02147 expression promotes the malignant progression of oral submucous fibrosis.

BACKGROUND: Key lncRNAs associated with the malignant progression of oral submucous fibrosis (OSF) to oral squamous cell carcinoma (OSCC) were identified. METHODS: Key lncRNAs with sequential changes from normal oral mucosa (NOM) to OSF to OSCC were identified based on the GEO database. Kaplan-Meier analysis was used to screen lncRNAs related to OSCC prognosis. Cox regression analysis was used to validate the independent prognostic value. qPCR was used to confirm the expression of the candidate lncRNAs. Gene set enrichment analysis (GSEA), nucleocytoplasmic separation assay, fluorescence in situ hybridization, RNA knockdown, western blot, and cell viability assay were performed to investigate the biological functions of the candidate lncRNA. A nomogram was constructed to quantitatively predict OSCC prognosis based on TCGA. RESULTS: Bioinformatics methods indicated that LINC02147 was sequentially downregulated from NOM to OSF to OSCC, as confirmed by clinical tissues and cells. Meanwhile, low LINC02147 expression, as an independent prognostic factor, predicted a poor prognosis for OSCC. GSEA and in vitro studies suggested that low LINC02147 expression promoted OSF malignant progression by promoting cell proliferation and differentiation. A LINC02147 signature-based nomogram successfully quantified each indicator's contribution to the overall survival of OSCC. CONCLUSIONS: Low LINC02147 expression promoted OSF malignant progression and predicted poor OSCC prognosis.