Upregulated expression of MMP-9 in gingival epithelial cells induced by prolonged stimulation with arecoline

Novel transcripts of EMT driving the malignant transformation of oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic, progressive, and fibrotic condition of the oral mucosa that carries an elevated risk of malignant transformation. We aimed to identify and validate novel genes associated with the regulation of epithelial-to-mesenchymal transition (EMT) in OSF. Genes regulating EMT were identified through differential gene expression analysis, using a LogFC threshold of -1 and + 1 and a padj value < 0.05, based on data from GEO datasets and the TCGA-HNSC datasets. The curated EMT genes were correlated with functional cancer states and subjected to clustering to identify candidate genes. Integration of bioinformatics and proteomics led to the discovery of the EMT genes MMP9, SPARC, and ITGA5 as novel candidates. Comprehensive pathway and immunohistochemical analyses confirmed their roles in regulating EMT in OSF, oral squamous cell carcinoma (OSCC), and OSF-associated squamous cell carcinoma (OSFSCC). The significant roles of MMP9, SPARC, and ITGA5 in fibrosis and malignancy suggest a novel mechanism in which fibrosis-associated type 2 EMT undergoes transition to type 3 EMT, driving OSF towards malignancy.

MiRNA Profiling of Areca Nut-Induced Carcinogenesis in Head and Neck Cancer

BACKGROUND

While miRNAs are increasingly recognized for their role in tumorigenesis, their involvement in head and neck cancer (HNC) remains insufficiently explored. Additionally, the carcinogenic mechanisms of areca nut, a major habitual carcinogen in Southeast Asia, are not well understood.

METHODS AND RESULTS

This study adopts a systematic approach to identify miRNA profiles associated with areca nut-induced HNC. Using miRNA microarray analysis, we identified 292 miRNAs dysregulated in areca nut-treated HNC cells, with 136 upregulated and 156 downregulated. Bioinformatic analysis of the TCGA-HNSC dataset uncovered a set of 692 miRNAs relevant to HNC development, comprising 449 overexpressed and 243 underexpressed in tumor tissues. Integrating these datasets, we defined a signature of 84 miRNAs, including 39 oncogenic miRNAs (OncomiRs) and 45 tumor-suppressive miRNAs (TsmiRs), highlighting their pivotal role in areca nut-induced carcinogenesis. MultiMiR analysis identified 740 genes cross-regulated by eight hub TsmiRs, significantly impacting key cancer-related pathways (p53, PI3K-AKT, MAPK, and Ras) and critical oncogenic processes. Moreover, we validated miR-499a-5p as a vital regulator, demonstrating its ability to mitigate areca nut-induced cancer progression by reducing cell migration, invasion, and chemoresistance.

CONCLUSIONS

Thus, this miRNA signature addresses a crucial gap in understanding the molecular underpinnings of areca nut-induced carcinogenesis and offers a promising platform for clinical applications in risk assessment, diagnosis, and prognosis of areca nut-associated malignancies.

Areca nut-induced metabolic reprogramming and M2 differentiation promote OPMD malignant transformation

BACKGROUND

Betel quid and its major ingredient, areca nut, are recognized by IARC as major risk factors in oral cancer development. Areca nut extract (ANE) exposure has been linked to OPMD progression and malignant transformation to OSCC. However, the detailed mechanism through which ANE acts on other cell types in the oral microenvironment to promote oral carcinogenesis remains elusive.

METHODS

Immunoprofiling of macrophages associated with OPMD and OSCC was carried out by immunohistochemical and immunofluorescence staining. Phosphokinase and cytokine arrays and western blotting were performed to determine the underlying mechanisms. Transwell assays were used to evaluate the migration-promoting effect of ANE. Hamster model was finally applied to confirm the in vivo effect of ANE.

RESULTS

We reported that M2 macrophages positively correlated with oral cancer progression. ANE induced M2 macrophage differentiation, CREB phosphorylation and VCAM-1 secretion and increased mitochondrial metabolism. Conditioned medium and VCAM-1 from ANE-treated macrophages promoted migration and mesenchymal phenotypes in oral precancer cells. In vivo studies showed that ANE enhanced M2 polarization and related signaling pathways in the oral buccal tissues of hamsters.

CONCLUSION

Our study provides novel mechanisms for areca nut-induced oral carcinogenesis, demonstrating that areca nut promotes M2 macrophage differentiation and secretion of oncogenic cytokines that critically activate malignant transformation of oral premalignant cells.

Doxycycline versus Curcumin for Inhibition of Matrix Metalloproteinase Expression and Activity Following Chemically Induced Inflammation in Corneal Cells

Purpose

Sulfur mustard (SM) is a potent blistering agent. This alkylating chemical agent has extremely toxic effects on the eye. MMP-2 and MMP-9 are the two most important matrix metalloproteinase enzymes involved in the pathology of chemical eye injuries. Curcumin is regarded as a natural anti-inflammatory agent. This study aims to compare the anti-inflammatory effects of curcumin versus doxycycline on chemically induced corneal injuries.

Methods

The HCE-2 cell line was used as a model for corneal cells. The effective concentrations of 2-chloroethyl ethyl sulfide (CEES) - as an analog of SM - doxycycline, and curcumin were determined using the MTT assay. The gene expression of MMP-2, MMP-9, and tissue inhibitors of metalloproteinase (TIMP-1) was evaluated by the real-time PCR method. Also, the activity of MMP-2 and MMP-9 enzymes was determined by zymography.

Results

The expression of the MMP-2 and MMP-9 genes increased 5- and 3.3-fold after exposure to CEES, respectively. Following the treatment with curcumin and doxycycline, MMP-2 expression decreased significantly. Also, after treatment with curcumin and doxycycline, the MMP-9 expression decreased 2.5- and 1.6-fold, respectively. The reduction in activity was 32% for MMP-2 and 56% for MMP-9 after treatment with curcumin. The corresponding values were 12% and 40% following doxycycline treatment. There was no significant difference between the effects of curcumin and doxycycline on reducing MMP-2 expression, but the difference was statistically significant in the case of MMP-9.

Conclusion

Doxycycline and curcumin can inhibit MMP expression and activity in chemically exposed corneal cells. Curcumin has a greater ability than doxycycline to inhibit MMP-2 and MMP-9 enzymes; however, the difference is statistically significant only in the case of MMP-9. After further validation, these substances can be introduced as anti- inflammatory agents to treat corneal chemical burns.

Association of Matrix Metalloproteinase-9 Genotypes With Nasopharyngeal Carcinoma Risk

BACKGROUND/AIM

The up-regulation of matrix metalloproteinase-9 (MMP-9) expression is a characteristic feature observed across various malignancies, including nasopharyngeal carcinoma (NPC). Nevertheless, the influence of MMP-9 genotype in the context of NPC remains underexplored. This study examined the implications of MMP-9 promoter rs3918242 genotypes on the susceptibility to NPC in Taiwan.

MATERIALS AND METHODS

In a cohort comprising 208 NPC cases and 416 healthy controls, genotyping of MMP-9 rs3918242 was conducted utilizing polymerase chain reaction-restriction fragment length polymorphism methodology.

RESULTS

Individuals harbouring the variant CT or TT genotype of MMP-9 rs3918242 did not demonstrate a discernible alteration in NPC risk when compared to wild-type CC carriers [odds ratio (OR)=0.83 and 0.79, with 95% confidence intervals (95%CI)=0.56-1.24 and 0.27-2.29; p=0.4205 and 0.8675, respectively]. Moreover, the presence of the variant T allele did not confer a modified risk of NPC (OR=0.84, 95%CI=0.60-1.19, p=0.3761). Intriguingly, a protective effect associated with the MMP-9 rs3918242 CT genotype against NPC risk was discerned among individuals abstaining from betel quid chewing behaviour (OR=0.51, 95%CI=0.30-0.87, p=0.0166). Notably, no significant association was established between the MMP-9 rs3918242 CT or TT genotype and NPC risk among individuals with or without smoking or alcohol consumption habits.

CONCLUSION

Presence of the variant CT or TT genotype at MMP-9 rs3918242 did not appear to substantially contribute to an elevated risk of NPC. Notably, a protective effect against NPC risk was observed in individuals carrying the CT genotype, particularly in those abstaining from betel quid chewing.

The Wound Environment Agent-based Model (WEABM): a digital twin platform for characterization and complex therapeutic discovery for volumetric muscle loss

Volumetric Muscle Loss (VML) injuries are characterized by significant loss of muscle mass, usually due to trauma or surgical resection, often with a residual open wound in clinical settings and subsequent loss of limb function due to the replacement of the lost muscle mass with non-functional scar. Being able to regrow functional muscle in VML injuries is a complex control problem that needs to override robust, evolutionarily conserved healing processes aimed at rapidly closing the defect in lieu of restoration of function. We propose that discovering and implementing this complex control can be accomplished by the development of a Medical Digital Twin of VML. Digital Twins (DTs) are the subject of a recent report from the National Academies of Science, Engineering and Medicine (NASEM), which provides guidance as to the definition, capabilities and research challenges associated with the development and implementation of DTs. Specifically, DTs are defined as dynamic computational models that can be personalized to an individual real world "twin" and are connected to that twin via an ongoing data link. DTs can be used to provide control on the real-world twin that is, by the ongoing data connection, adaptive. We have developed an anatomic scale cell-level agent-based model of VML termed the Wound Environment Agent Based Model (WEABM) that can serve as the computational specification for a DT of VML. Simulations of the WEABM provided fundamental insights into the biology of VML, and we used the WEABM in our previously developed pipeline for simulation-based Deep Reinforcement Learning (DRL) to train an artificial intelligence (AI) to implement a robust generalizable control policy aimed at increasing the healing of VML with functional muscle. The insights into VML obtained include: 1) a competition between fibrosis and myogenesis due to spatial constraints on available edges of intact myofibrils to initiate the myoblast differentiation process, 2) the need to biologically "close" the wound from atmospheric/environmental exposure, which represents an ongoing inflammatory stimulus that promotes fibrosis and 3) that selective, multimodal and adaptive local mediator-level control can shift the trajectory of healing away from a highly evolutionarily beneficial imperative to close the wound via fibrosis. Control discovery with the WEABM identified the following design principles: 1) multimodal adaptive tissue-level mediator control to mitigate pro-inflammation as well as the pro-fibrotic aspects of compensatory anti-inflammation, 2) tissue-level mediator manipulation to promote myogenesis, 3) the use of an engineered extracellular matrix (ECM) to functionally close the wound and 4) the administration of an anti-fibrotic agent focused on the collagen-producing function of fibroblasts and myofibroblasts. The WEABM-trained DRL AI integrates these control modalities and provides design specifications for a potential device that can implement the required wound sensing and intervention delivery capabilities needed. The proposed cyber-physical system integrates the control AI with a physical sense-and-actuate device that meets the tenets of DTs put forth in the NASEM report and can serve as an example schema for the future development of Medical DTs.

Systematic Review of Roles of Arecoline and Arecoline N-Oxide in Oral Cancer and Strategies to Block Carcinogenesis

Betel quid and areca nut are complex mixture carcinogens, but little is known about whether their derived single-agent arecoline or arecoline N-oxide (ANO) is carcinogenic, and the underlying mechanisms remain unclear. In this systematic review, we analyzed recent studies on the roles of arecoline and ANO in cancer and strategies to block carcinogenesis. In the oral cavity, flavin-containing monooxygenase 3 oxidizes arecoline to ANO, and both alkaloids conjugate with N-acetylcysteine to form mercapturic acid compounds, which are excreted in urine, reducing arecoline and ANO toxicity. However, detoxification may not be complete. Arecoline and ANO upregulated protein expression in oral cancer tissue from areca nut users compared to expression levels in adjacent normal tissue, suggesting a causal relationship between these compounds and oral cancer. Sublingual fibrosis, hyperplasia, and oral leukoplakia were diagnosed in mice subjected to oral mucosal smearing of ANO. ANO is more cytotoxic and genotoxic than arecoline. During carcinogenesis and metastasis, these compounds increase the expression of epithelial-mesenchymal transition (EMT) inducers such as reactive oxygen species, transforming growth factor-β1, Notch receptor-1, and inflammatory cytokines, and they activate EMT-related proteins. Arecoline-induced epigenetic markers such as sirtuin-1 hypermethylation, low protein expression of miR-22, and miR-886-3-p accelerate oral cancer progression. Antioxidants and targeted inhibitors of the EMT inducers used reduce the risk of oral cancer development and progression. Our review findings substantiate the association of arecoline and ANO with oral cancer. Both of these single compounds are likely carcinogenic to humans, and their mechanisms and pathways of carcinogenesis are useful indicators for cancer therapy and prognosis.

Carcinogenic Effects of Areca Nut and Its Metabolites: A Review of the Experimental Evidence

Oral cancers (OC) are among the most frequent malignancies encountered in Southeast Asia, primarily due to the prevalent habit of betel quid (BQ) and smokeless tobacco use in this region. Areca nut (AN), the primary ingredient in BQ, contains several alkaloids, including arecoline, arecaidine, guvacoline, and guvacine. These have been associated with both the AN abuse liability and carcinogenicity. Additionally, variations in AN alkaloid levels could lead to differences in the addictiveness and carcinogenic potential across various AN-containing products. Recent studies based on animal models and in vitro experiments show cellular and molecular effects induced by AN. These comprise promoting epithelial-mesenchymal transition, autophagy initiation, tissue hypoxia, genotoxicity, cytotoxicity, and cell death. Further, clinical research endorses these undesired harmful effects in humans. Oral submucosal fibrosis, a potentially malignant disease of the oral cavity, is predominantly reported from the geographical areas of the globe where AN is habitually chewed. OC in chronic AN users presents a more aggressive phenotype, such as resistance to anti-cancer drugs. The available evidence on the carcinogenicity of AN based on the findings reported in the recently published experimental studies is discussed in the present review.

In Vitro Culture Expansion and Characterization of Buccal Mucosal Epithelial Cells for Tissue Engineering Applications in Urethral Stricture After Transportation Using a Thermoreversible Gelation Polymer

Introduction: The transportation of tissues from hospitals to clinical laboratories for cell therapy is an essential component of regenerative medicine. Previously, we used laboratory-cultured mucosal cells from buccal epithelium expanded and encapsulated using a scaffold-hybrid approach to the urethral stricture (BEES-HAUS) procedure. In this study, to improve the outcomes, we compared the thermoreversible gelation polymer (TGP) transportation procedure with conventional culture methods, and reported its advantages. Methods: Human buccal mucosal tissues in Phase I of the study were transported in Euro-Collins solution (ECS) and the cells obtained were cultured in two-dimensional (2D) Dulbecco's modified Eagle's medium (DMEM), CnT-Prime epithelial 2D differentiation medium (CnT-PR), and a three-dimensional (3D)-TGP scaffold. In Phase II, tissues were transported in a TGP cocktail and the ECS. The cells were cultured in 2D-DMEM and 3D-TGP, quantified, and characterized by immunohistochemistry. Results: The cells in 3D-TGP culture maintained epithelial morphology in a better manner compared with 2D-DMEM, in which they developed fibroblast-like morphology. The TGP-transported cells grew rapidly. Immunohistochemical analysis results for AE1/AE3, EGFR, integrin-β1, p63, and p75 were intensely positive in 3D-TGP. Conclusion: The TGP-based cocktail used in human buccal tissue transportation yielded cells with better morphology maintenance. The TGP scaffold provides an optimal in vitro environment wherein epithelial cells better maintain their native phenotype compared to those cultured through conventional methods. These results suggest using TGP for the transportation and culture of human buccal tissues for clinical applications. In addition, the use of a TGP-based cocktail for the transport of other tissues for regenerative medicine applications is worth further analysis.

Aberrant expression of DUSP4 is a specific phenomenon in betel quid-related oral cancer

Oral cancer due to betel quid chewing habit is very common in South Asian countries. We attempted to detect the presence of a novel gene in epithelial cells stimulated with arecoline, a main component of betel quid. Human gingival epithelial progenitors were cultured and treated with a 3-day alternating regimen with/without 50 μg/ml arecoline for 1 month. DNA microarray and methylation arrays were analyzed to identify the candidate genes. Immunohistochemical staining was performed in the tissue samples. Genome-wide analyses, quantitative reverse transcription PCR and quantitative methylation-specific PCR revealed DUSP4 as the most significant and promising gene. The methylation levels of DUSP4 were significantly higher in the betel quid-related oral squamous cell carcinoma (OSCC) than those in the non-related OSCC and controls (Mann-Whitney U test, p < 0.05). The number of DUSP4 immunopositive cells in betel quid-related OSCC was significantly higher than those from the non-chewing patients and the controls (p < 0.05). Hypermethylation of DUSP4 may be considered as a specific event in betel quid-related oral cancer.

BactericidalActivity of Crevicular Polymorphonuclear Neutrophils in Chronic Periodontitis Patients and Healthy Subjects under the Influence of Areca Nut Extract: An In Vitro Study

Arecanutchewing is an established risk factor for oral submucous fibrosis (OSMF), but its role in periodontal disease has not yet been defined. Thisstudy aimed to assess the effect of areca nut extracts (ANE) on the bactericidal activity of crevicular polymorphonuclear neutrophils (cPMNs) in healthy subjects and chronic periodontitis (CP) patients. An in vitro study was designed with an equal number of (n = 30) gingival crevicular fluid (GCF) samples collected from CP patients and healthy subjects. Bactericidal activity and hydrogen peroxide (H2O2) assays were performed with the GCF samples pre-treated with extracts of two varieties of areca nut: ripe and tender. Simultaneously, controls were also carried out with Hank’s balanced salt solution (HBSS) and catechin. Independent t-test and one-way analysis of variance (ANOVA), along with post-hoc analysis, were employed for statistical analysis. In both study groups, a significant reduction (p < 0.01)in the bactericidal activity was noted when the samples treated with the ripe areca nut (rANE) were compared with the tender variant (tANE). Similarly, H2O2 levels were significantly reduced (p < 0.001) in the rANE in contrast to tANE for both study groups. The above results were significant within the group but were found to be non-significant between the study groups, except when it was treated with HBSS (p < 0.001). In the present study, it was found that there was a reduction in the bactericidal activity and H2O2 production of cPMNs in both healthy subjects and CP patients in the presence of areca nut extract. Moreover, the effect of rANE on cPMNs was more detrimental than tANE.

Network-based identification of signature genes KLF6 and SPOCK1 associated with oral submucous fibrosis

The molecular mechanism of oral submucous fibrosis (OSF) is yet to be fully elucidated. The identification of reliable signature genes to screen patients with a high risk of OSF and to provide oral cancer surveillance is therefore required. The present study produced a filtering criterion based on network characteristics and principal component analysis, and identified the genes that were involved in OSF prognosis. Two gene expression datasets were analyzed using meta-analysis, the results of which revealed 1,176 biologically significant genes. A co-expression network was subsequently constructed and weighted gene modules were detected. The pathway and functional enrichment analyses of the present study allowed for the identification of modules 1 and 2, and their respective genes, SPARC (osteonectin), cwcv and kazal like domain proteoglycan 1 (SPOCK1) and kruppel like factor 6 (KLF6), which were involved in the occurrence of OSF. The results revealed that both genes had a prominent role in epithelial to mesenchymal transition during OSF progression. The genes identified in the present study require further exploration and validation within clinical settings to determine their roles in OSF.

DNA hypermethylation of sirtuin 1 (SIRT1) caused by betel quid chewing-a possible predictive biomarker for malignant transformation

BACKGROUND

DNA hypermethylation of tumor suppressor genes is observed in precancerous lesions and oral cancer of individuals with the habits of betel quid (BQ) chewing. SIRT1 has been identified as playing a role in the maintenance of epithelial integrity, and its alteration is often related to carcinogenesis. However, the methylation and transcription status of SIRT1 in patients with BQ chewing-related oral cancer has not been investigated. We examined the methylation status of SIRT1 in paraffin-embedded tissue samples of oral squamous cell carcinoma (OSCC) obtained from BQ chewing and non-chewing patients and in tissue samples from healthy control subjects. In addition, we examined whether the hypermethylation of SIRT1 followed by its transcriptional downregulation in the human gingival epithelial cells could be caused by arecoline, a major component of BQ. Furthermore, we investigated the methylation status of SIRT1 in smear samples of macroscopically healthy buccal mucosa from subjects with a habit of BQ chewing.

RESULTS

SIRT1 was significantly hypermethylated in tissue samples of OSCC from BQ chewers and non-chewers than in oral mucosa from healthy control subjects. Results also showed that the hypermethylation level of SIRT1 was significantly higher in OSCC of patients with BQ chewing habits than in those of non-chewing habits (p < 0.05). Our in vitro model showed that hypermethylation is followed by downregulation of the transcriptional level of SIRT1 (p < 0.05). The methylation levels of SIRT1 in the smear samples obtained from BQ chewing individuals were significantly higher than those in the samples obtained from individuals that did not chew BQ. The duration of BQ chewing habits was correlated positively to the frequency of SIRT1 hypermethylation (p < 0.05).

CONCLUSIONS

Our results suggest that DNA hypermethylation of SIRT1 is involved in the occurrence of oral cancer in BQ chewing patients and that hypermethylation in the oral mucosa of BQ chewers could be a predictive marker for the occurrence of malignant transformation. This is the first report that showed DNA hypermethylation in clinically healthy oral epithelium of BQ chewers. Our study shows evidence that DNA hypermethylation may be an early event of oral carcinogenesis prior to observable clinical changes.

Multifaceted Mechanisms of Areca Nuts in Oral Carcinogenesis: the Molecular Pathology from Precancerous Condition to Malignant Transformation

Oral cancer is one of the most frequent malignant diseases worldwide, and areca nut is a primary carcinogen causing this cancer in Southeast Asia. It has been widely reported that areca nut induced several cytotoxic effects in oral cells, including ROS generation, inflammation, tissue hypoxia, DNA damage, and cell invasion. Recently, through chronic exposure model, more extensive pathological effects due to areca nut have been found. These include the induction of autophagy, promotion of epithelial- mesenchymal transition, and facilitation of cancer stemness conversion. Clinical findings support these adverse effects. Oral submucosal fibrosis, a premalignant condition, is prevalent in the area with habitual chewing of areca nuts. Consistently, oral cancer patients with habitual chewing areca nut exhibit more aggressive phenotypes, including resistance to chemo-radiotherapy. In this review, we comprehensively discuss and concisely summarize the up-to-date molecular and cellular mechanisms by which areca nuts contribute to malignant transformation. This review may provide critical information regarding clinical applications in risk assessment, disease prevention, diagnosis, and personalized therapeutics for areca nut-induced oral malignancy.

Sirtuin 1 and oral cancer

The sirtuins (SIRTs) are a family of highly conserved histone deacetylases (HDACs) consisting of seven members (SIRT1-SIRT7). Over the past few decades, SIRT1 has been the most extensively studied and garnered tremendous attention in the scientific community due to its emerging role in cancer biology. However, its biological role in the regulation of oral cancer is not yet fully understood. Owing to contradictory findings regarding the role of SIRT1 in oral cancer, debate about it continues. The present study discusses the biological roles and potential therapeutic implications of SIRT1 in precancerous oral lesions and oral cancer.