Arecoline induced cell cycle arrest, apoptosis, and cytotoxicity to human endothelial cells

The Value of the Nutritional Indicators in Predicting Free Flap Failure From a Multicentre Database

OBJECTIVE

Nutritional and inflammatory statuses have been associated with complications in microvascular-free flaps during head and neck surgeries. This study aimed to evaluate the potential of nutritional indicators in predicting postoperative free flap complications.

STUDY DESIGN

We conducted a 20-year retrospective, case-control study within a defined cohort.

SETTING

The study involved head and neck cancer patients from the Chang Gung Research Database who underwent simultaneous tumor ablation and free flap wound reconstruction between January 1, 2001, and December 31, 2019.

METHODS

We employed logistic regression and stratified analysis to assess the risk of free flap complications and the subsequent need for flap revision or redo in relation to nutritional indicators and other clinical variables.

RESULTS

Of the 8066 patients analyzed, 687 (8.5%) experienced free flap complications. Among these, 197 (2.4%) had free flap failures necessitating a redo of either a free flap or a pedicled flap. Beyond comorbidities such as chronic obstructive pulmonary disease, end-stage renal disease, and a history of prior radiotherapy, every 10-unit decrease in the preoperative prognostic nutritional index (PNI) was consistently associated with an increased risk of both free flap complications and failure. The covariate-adjusted odds ratios were 1.90 (95% confidence interval [CI]: 1.42-2.54) and 1.89 (95% CI: 1.13-3.17), respectively.

CONCLUSION

A lower preoperative PNI suggests a higher likelihood of microvascular free flap complications in head and neck surgeries. Further randomized controlled trial designs are required to establish causality.

Comprehensive insights into areca nut: active components and omics technologies for bioactivity evaluation and quality control

Areca nut (AN), the fruit or seed of Areca catechu Linn, has many uses, including chewing and medicinal purposes. It has sparked worries about health due to the presence of alkaloids. Chewing AN may have a variety of negative consequences; however, the medicinal use of AN has no notable adverse effects. To completely understand and effectively use AN, researchers have investigated its chemical makeup or biological activity, analyzed the variations between different AN species and different periods, and improved extraction and processing procedures. Today, an increasing number of researchers are exploring the underlying reasons for AN variations, as well as the molecular mechanisms of biosynthesis of chemical components, to comprehend and change AN at the genetic level. This review presents an overview of the clinical study, pharmacology, and detection of the main bioactive components in AN, and the main factors influencing their content, delving into the omics applications in AN research. On the basis of the discussions and summaries, this review identifies current research gaps and proposes future directions for investigation.

Areca nut and oral cancer

INTRODUCTION

The association between areca nut consumption and oral cancer has been a subject of increasing concern in global public health.

GLOBAL PERSPECTIVE

Areca nut, often chewed in various forms such as betel quid, is deeply rooted in cultural practices across Asia and other parts of the world. Epidemiological studies consistently reveal a significant correlation between areca nut use and the incidence of oral cancer, emphasizing the need for targeted preventive measures. The complex interplay of areca nut's bioactive compounds, particularly arecoline, with cellular processes, contributes to the initiation and progression of oral carcinogenesis. Mechanistic insights into the genotoxic and cytotoxic effects of its components underscore the urgency for comprehensive public health interventions.

PUBLIC HEALTH

Efforts to address this public health challenge involve multidisciplinary approaches, encompassing education, policy implementation, and behavioral interventions. Understanding the socio-cultural factors influencing areca nut consumption is pivotal for designing effective awareness campaigns and cessation programs.

CONCLUSION

As oral cancer remains a significant global health burden, unraveling the nuanced relationship between areca nut and its role in oral carcinogenesis is crucial for advancing preventive strategies and mitigating the impact of this modifiable risk factor.

Stromal thrombospondin 1 suppresses angiogenesis in oral submucous fibrosis

A decline in mucosal vascularity is a histological hallmark of oral submucous fibrosis (OSF), a premalignant disease that is largely induced by betel quid chewing. However, the lack of available models has challenged studies of angiogenesis in OSF. Here, we found that the expression of thrombospondin 1 (THBS1), an endogenous angiostatic protein, was elevated in the stroma of tissues with OSF. Using a fibroblast-attached organoid (FAO) model, the overexpression of THBS1 in OSF was stably recapitulated in vitro. In the FAO model, treatment with arecoline, a major pathogenic component in areca nuts, enhanced the secretion of transforming growth factor (TGF)-β1 by epithelial cells, which then promoted the expression of THBS1 in fibroblasts. Furthermore, human umbilical vein endothelial cells (HUVECs) were incorporated into the FAO to mimic the vascularized component. Overexpression of THBS1 in fibroblasts drastically suppressed the sprouting ability of endothelial cells in vascularized FAOs (vFAOs). Consistently, treatment with arecoline reduced the expression of CD31 in vFAOs, and this effect was attenuated when the endothelial cells were preincubated with neutralizing antibody of CD36, a receptor of THBS1. Finally, in an arecoline-induced rat OSF model, THBS1 inhibition alleviated collagen deposition and the decline in vascularity in vivo. Overall, we exploited an assembled organoid model to study OSF pathogenesis and provide a rationale for targeting THBS1.

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.

Oxidative Stress Enzyme as Markers in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma Patients

Oxidative stress is a recognized factor that poses a significant risk for the development of Oral Squamous Cell Carcinoma (OSCC) and Oral Submucous Fibrosis (OSMF), as it leads to the generation of Reactive Oxygen Species. In recent years, there has been significant research on the enzymes MDA (malondialdehyde) and SOD (superoxide dismutase), investigating their potential role in the development of OPMD and OSCC. These enzymes have emerged as promising biomarkers due to their ability to provide a less invasive, cost-effective, and objective diagnostic method. Furthermore, they can be used to monitor disease progression and assess the effectiveness of therapy. The aim of this study was to assess the levels of MDA and SOD in the serum of patients diagnosed with OSCC and OSMF. Study group comprised of 60 patients, out of which 20 cases of clinically diagnosed OSCC patients and 20 cases of OSMF and 20 cases pf control comprising of healthy patients were recruited. Estimation MDA and SOD was done by ELISA. The statistical analysis was done using SPSS analysis. When comparing the levels of MDA and SOD between the OSCC and OSMF groups and the control group, statistically significant findings indicated elevated levels of malondialdehyde and reduced levels of superoxide dismutase in both the OSCC and OSMF groups. In this study, the assessment of lipid peroxidation through MDA levels revealed elevated concentrations in both the OSCC and OSMF groups when compared to the control group. Specifically, the order of MDA levels was observed as OSCC > OSMF > Control. Conversely, antioxidant enzyme levels, such as SOD, exhibited decreased concentrations in the OSCC and OSMF groups compared to the control group, with the order of SOD levels being Control > OSMF > OSCC. Consequently, the findings suggest that MDA and SOD can be considered potential biomarkers for identifying and monitoring OSCC and OSMF diseases.

Correlation Between Clinical and Histopathological Stagings of Oral Submucous Fibrosis: A Clinicopathological Cognizance of 238 Cases From South India

Background  This paper aims to descriptively present the clinico-demographic and pathological profile of 238 cases of oral submucous fibrosis (OSMF) with emphasis on the correlation between clinical and histopathological classification systems and the incidence of malignant transformation. Methods A total of 7098 oral biopsies were retrospectively retrieved over a period of 13 years, out of which 238 cases of OSMF were included in the present study. Data were analyzed for age, gender, habits, clinical symptoms, functional staging, histological staging, type and nature of epithelium, signet-ring cell changes, presence/absence of dysplasia or transformation squamous cell carcinoma, and treatment. Results Clinically and histologically, most cases were moderately advanced. Men outnumbered women. The prevalence of dysplasia was found to be 23.94% and the malignant transformation rate was estimated to be 13.8%. There was a significant correlation between clinical staging with age and histological grading. No correlation was found between histological staging and the age of the patients. Conclusions OSMF is a habit-related progressive chronic oral condition with a high malignant transformation rate. Multimodal treatment with auxiliary physiotherapy helps in the improvement of the clinical symptoms.

Rapidly analyzing of ingredients during chewing and processing of areca nut using feature-based molecular networking

As a traditional herbal medicine and food in China and many other Asian countries, the areca nut (Areca catechu L.) is not only widely used for the treatment of various diseases, but also popular as a chewing hobby. However, as a first-class carcinogen designated by IARC, clinical studies have shown that long-term chewing of areca nut is associated with oral mucosal diseases and even oral cancer. Moreover, the incidence of these diseases varies regionally, suggesting that it may be related to edible methods in different regions. In this study, UPLC-Q-TOF-MSE was combined with feature-based molecular networking to systematically characterise the chemical ingredients of areca nut. Based on these results, the ingredients of different edible parts and edible methods was rapidly compared. The compositional changes during the production process were also analysed. The obtained results provide a foundation for the scientific utilisation of areca nut.

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.

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.

A biomaterial-based therapy using a sodium hyaluronate/bioglass composite hydrogel for the treatment of oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic, inflammatory and potentially malignant oral disorder. Its pathophysiology is extremely complex, including excessive collagen deposition, massive inflammatory infiltration, and capillary atrophy. However, the existing clinical treatment methods do not fully take into account all the pathophysiological processes of OSF, so they are generally low effective and have many side effects. In the present study, we developed an injectable sodium hyaluronate/45S5 bioglass composite hydrogel (BG/HA), which significantly relieved mucosal pallor and restricted mouth opening in OSF rats without any obvious side effects. The core mechanism of BG/HA in the treatment of OSF is the release of biologically active silicate ions, which inhibit collagen deposition and inflammation, and promote angiogenesis and epithelial regeneration. Most interestingly, silicate ions can overall regulate the physiological environment of OSF by down-regulating α-smooth muscle actin (α-SMA) and CD68 and up-regulating CD31 expression, as well as regulating the expression of pro-fibrotic factors [transforming growth factor-β1 (TGF-β1), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α) and tissue inhibitors of metalloproteinase-1 (TIMP-1)] and anti-fibrotic factors [interleukin-1β (IL-1β)] in macrophage. In conclusion, our study shows that BG/HA has great potential in the clinical treatment of OSF, which provides an important theoretical basis for the subsequent development of new anti-fibrotic clinical preparations. STATEMENT OF SIGNIFICANCE: : Oral submucous fibrosis (OSF) is a chronic, inflammatory and potentially malignant mucosal disease with significant impact on the quality of patients' life. However, the existing clinical treatments have limited efficacy and many side effects. There is an urgent need for development of specific drugs for OSF treatment. In the present study, bioglass (BG) composited with sodium hyaluronate solution (HA) was used to treat OSF in an arecoline-induced rat model. BG/HA can significantly inhibit collagen deposition, regulate inflammatory response, promote angiogenesis and repair damaged mucosal epithelial cells, and thereby mitigate the development of fibrosis in vivo.

In Vitro Characterization of Inhibitors for Lung A549 and Leukemia K562 Cell Lines from Fungal Transformation of Arecoline Supported by In Silico Docking to M3-mAChR and ADME Prediction

The search for anticancer drugs is of continuous interest. Arecoline is an alkaloid with anticancer activity. Herein, the metabolism of arecoline through fungal transformation was investigated for the discovery of potential anticancer drugs with higher activity and selectivity. Compounds 1–5 were isolated, and their structures were fully elucidated using various spectroscopic analyses, including 1D and 2D NMR, ESIMS, and HRESIMS. This is the first report for the isolation of compounds 1 and 2. An MTT assay was performed to determine the cytotoxic activity of arecoline and its metabolites in vitro using non-small-cell lung cancer A549 and leukemia K562 cell lines compared to staurosporine and doxorubicin as positive controls. For the non-small-cell lung A549 cell line, arecoline hydrobromide, staurosporine, and doxorubicin resulted in IC50 values of 11.73 ± 0.71 µM, 10.47 ± 0.64 µM, and 5.05 ± 0.13 µM, respectively, while compounds 1, 3, and 5 exhibited IC50 values of 3.08 ± 0.19 µM, 7.33 ± 0.45 µM, and 3.29 ± 0.20 µM, respectively. For the leukemia K562 cell line, the IC50 values of arecoline hydrobromide, staurosporine, and doxorubicin were 15.3 ± 1.08 µM, 5.07 ± 0.36 µM, and 6.94 ± 0.21 µM, respectively, while the IC50 values of compounds 1, 3 and 5 were 1.56 ± 0.11 µM, 3.33 ± 0.24 µM, and 2.15 ± 0.15 µM, respectively. The selectivity index value of these compounds was higher than 3. These results indicated that compounds 1, 3, and 5 are very strong cytotoxic agents with higher activity than the positive controls and good selectivity toward the tested cancer cell lines. Cell cycle arrest was then studied by flow cytometry to investigate the apoptotic mechanism. Docking simulation revealed that most compounds possessed good binding poses and favorable protein-ligand interactions with muscarinic acetylcholine receptor M3-mAChR protein. In silico study of pharmacokinetics using SwissADME predicted compounds 1–5 to be drug-like with a high probability of good oral bioavailability.

Hydrogen sulfide prevents arecoline-induced neurotoxicity via promoting leptin/leptin receptor signaling pathway

Arecoline, a major alkaloid of the areca nut, has potential toxicity to the nervous system. Our previous study reveals that the neurotoxicity of arecoline involves in inhibited endogenous hydrogen sulfide (H₂ S) generation. Therefore, the present study investigated whether exogenous H₂ S protects against arecoline-induced neurotoxicity and further explore the underlying mechanisms focusing on leptin/leptin receptor signaling pathway. The cell viability was measured by CCK-8 kit. The apoptosis were detected by Hoechst 33258 and Annexin V/PI (propidium iodide) staining. The protein expressions were determined by Western blot analysis. Our results demonstrated that NaHS, an exogenous H₂ S donor, significantly increases the cell viability, decreases apoptosis ratio, and reduces caspase-3 activity as well as Bax/Bcl-2 ratio in PC12 cells exposed to arecoline, indicating the protection of H₂ S against arecoline-induced cytotoxicity and apoptosis. Also, NaHS attenuated arecoline-induced endoplasmic reticulum (ER) stress, as evidenced by the decreases in the expressions of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and Cleaved caspase-12. Meanwhile, NaHS promoted leptin/leptin receptor signaling pathway in arecoline-exposed PC12 cells, as illustrated by upregulations of leptin and leptin receptor expressions. Furthermore, leptin tA, an antagonist of leptin receptor, obviously abolished the inhibitory effects of NaHS on arecoline-induced cytotoxicity, apoptosis, and ER stress in arecoline-exposed PC12 cells. Taken together, these results suggested that H₂ S prevents arecoline-induced neurotoxicity via enhancing the leptin/leptin receptor signaling pathway.

Improvement of autophagic flux mediates the protection of hydrogen sulfide against arecoline-elicited neurotoxicity in PC12 cells

Arecoline, the most abundant alkaloid of the areca nut, induces toxicity to neurons. Hydrogen sulfide (H₂S) is an endogenous gas with neuroprotective effects. We recently found that arecoline reduced endogenous H₂S content in PC12 cells. In addition, exogenously administration of H₂S alleviated the neurotoxicity of arecoline on PC12 cells. Increasing evidence has demonstrated the neuroprotective role of improvement of autophagic flux. Therefore, the aim of the present work is to explore whether improvement of autophagic flux mediates the protection of H₂S against arecoline-caused neurotoxicity. Transmission electron microscope (TEM) for observation of ultrastructural morphology. Western blotting was used to detect protein expression of the related markers. Functional analysis contained LDH release assay, Hoechst 33,258 nuclear staining and flow cytometry were used to detect cytotoxicity and apoptosis. In the present work, we found that arecoline disrupted autophagy flux in PC12 cells as evidenced by accumulation of autophagic vacuoles, increase in LC3II/LC3I, and upregulation of p62 expression in PC12 cells. Notably, we found that sodium hydrosulfide (NaHS), the donor of H₂S improved arecoline-blocked autophagy flux in PC12 cells. Furthermore, we found that blocking autophagic flux by chloroquine (CQ), the inhibitor of autophagy flux, antagonized the inhibitory role of NaHS in arecoline-induced cytotoxicity apoptosis and endoplasmic reticulum (ER) stress. In conclusion, H₂S improves arecoline-caused disruption of autophagic flux to exert its protection against the neurotoxicity of arecoline.

Malondialdehyde, an Oxidative Stress Marker in Oral Squamous Cell Carcinoma-A Systematic Review and Meta-Analysis

Objective: To qualitative and quantitatively review published literature assessing the oxidative stress marker malondialdehyde (MDA) in oral squamous cell carcinoma (OSCC). Methodology: Pubmed (MeSH), Science Direct, Scopus, Web of Science, Willey Online Library, Cochrane, and Cross Reference were searched for studies assessing MDA levels in OSCC samples. Results: From the 1008 articles identified, 849 were excluded based on title and abstract screening due to duplication and irrelevance to the topic of interest. Full-text assessment of the remaining 159 articles led to the inclusion of only 46 articles that satisfied the selection criteria. Of these, only 26 studies had data compatible for quantitative analysis. The MDA levels in OSCC groups are significantly increased (p < 0.00001) in plasma, serum, and saliva samples in the majority of the studies evaluated. In contrast, MDA levels in OSCC tissue samples are significantly attenuated (p < 0.00001) compared to healthy controls, supported by fewer studies. Conclusions: The augmented MDA levels in plasma, serum, and saliva samples of the OSCC reflect the heightened oxidative stress level accurately. Further studies are required to understand the attenuated MDA levels in the tissue samples of OSCC. Correlation analysis between MDA levels with established clinicopathological prognostic markers could aid in formulating oxidative stress-based prognostication and treatment planning.

A Meta-Analysis in Assessing Oxidative Stress Using Malondialdehyde in Oral Submucous Fibrosis

Objective This study aimed to evaluate the oxidative stress (OS) marker Malondialdehyde (MDA) in oral submucous fibrosis with available literature.

Materials and Methods We conducted a literature search electronically in PubMed (MeSH), Science Direct, Scopus, and Google Scholar using specific keywords.

Results A systematic search in PubMed, Science Direct, and Google Scholar identified 334 articles. Of these, four were duplicate reports, and three were animal studies. After reading the abstracts of the collected articles, 288 articles were excluded for the following reasons: low quality, not relevant to the research question, or did not meet the inclusion criteria. The remaining 46 articles were chosen for full-text assessment. Finally, the present qualitative synthesis included 23 articles for evaluation. The selected studies in MDA analysis in a random-effects model showed higher heterogeneity (Q = 477.636, p < 0.001, I ² = 95.394%). The standard difference in mean MDA concentration between oral submucous fibrosis (OSMF) and healthy subjects was estimated as 2.73 nmol/mL (95% confidence interval: 2.08–3.38).

Conclusion The selected studies showed significantly higher MDA levels in various biological samples of patients with OSMF. Therefore, further studies are needed to estimate oxidative stress levels by using different biomarkers in OSMF to direct future therapy.

Genetic and Proteinic Linkage of MAO and COMT with Oral Potentially Malignant Disorders and Cancers of the Oral Cavity and Pharynx

Simple Summary

The prevention and treatment of cancers of the oral cavity and pharynx are currently important issues for national health. Currently, the incidence of oral cavity and pharynx cancers is globally the highest in Taiwanese men. Regarding the occurrence of oral cavity and pharynx cancers and oral potentially malignant disorders (OPMD), no report has ascertained how betel quid (BQ) can induce the expression of monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). We aimed to explore the role and clinical significance of specific markers of BQ exposure and human susceptibility to MAO and COMT. Our findings highlight the association of MAO and COMT biomarkers to risks of oral and pharyngeal cancers and OPMD. These novel findings will provide important strategies for disease prevention, early clinical diagnosis, and treatment effectiveness, and will offer a strong foundation to reduce BQ-related cancers of the oral cavity and pharynx and OPMD.

Abstract

Betel quid (BQ), a group I human carcinogen, strongly contributes to an increased risk of oral potentially malignant disorders (OPMD) and cancers of the oral cavity and pharynx. This study was conducted to discover whether monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) variants play a potential role in the risk assessment of oral cavity and pharynx cancers and OPMD, particularly among BQ users. We applied a case–control study to confirm the polymorphism of MAO and COMT using single-nucleotide polymorphisms. We used qRT-PCR, Western blotting, and immunohistochemistry (IHC) to determine MAO and COMT expression. Carriers of the MAOA rs6323 G-allele, MAOB rs6324 G-allele, and COMT rs4633 C/C-genotype had a prominently increased risk of oral cavity and pharynx cancers (AOR = 56.99; p < 0.001). Compared to adjacent noncancerous tissues, a significant downregulation of MAO and COMT expression was exhibited in cancerous tissues (p < 0.01). Furthermore, in different cell models, MAO and COMT expression was significantly downregulated with an increased dose of arecoline (p < 0.01). In personalized preventive medicine for oral and pharyngeal cancers, our findings are the first to demonstrate the potential role of lower MAO and COMT expression levels, with the risk polymorphisms utilized as clinical biomarkers.

Triphala extract negates arecoline-induced senescence in oral mucosal epithelial cells in vitro

Background

Arecoline found in areca nut causes oral submucous fibrosis. Triphala is an Ayurvedic medicinal preparation used to improve overall physical wellness that has also been shown to improve oral health.

Objectives

To assess the activity of Triphala extract on arecoline-induced senescence in oral mucosal epithelial cells in vitro.

Materials and methods

Oral mucosal epithelial cells were isolated and cultured in vitro. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to assess the viability of treated cells, while senescence was assessed by senescence-associated-β-galactosidase staining. Cell surface marker expression was analyzed by flow cytometry. Finally, real-time quantitative polymerase chain reaction was performed to examine gene expression levels.

Results

Triphala extract (5 µg/mL) reversed the cell senescence activity of arecoline, as evidenced by reduced β-galactosidase activity, increased Ki-67 marker expression, and reduced expression of senescence-related genes p16 and p21.

Conclusion

Triphala extract helped to reduce the pathological effects of arecoline-induced pathogenesis.

Clinical relevance.

Arecoline found in the areca nut causes oral pathological conditions including oral submucous fibrosis. Our results showed that Triphala counteracted the adverse effects of arecoline, in particular, negating senescence in oral mucosal epithelial cells. As a translational effect, Triphala treatment could restore normal epithelial thickness in oral submucous fibrosis, thus reducing the clinical severity of the disease. This reestablishment of oral homeostasis would help to improve oral health-related quality of life in patients with oral submucous fibrosis.

Suppression of miR-886-3p mediated by arecoline (ARE) contributes to the progression of oral squamous cell carcinoma

Previous studies have reported that as the main extract of areca nut, arecoline (ARE) causes DNA damage and in turn contributes to the carcinogenesis of oral epithelial cells. It has been reported that ARE can inhibit the expression of miR-886-3p. In the current study, we aimed to explore the expression and biological functions of miR-886-3p in oral squamous cell carcinoma (OSCC). Herein, we demonstrated that in OSCC cells treated with ARE, the expression level of miR-886-3p was negatively correlated with the concentration of ARE. Compared with adjacent tissue, the expression level of miR-886-3p in OSCC tissue was remarkably downregulated. Transfection of miR-886-3p mimics markedly decreased viability, migration and invasion of OSCC cells. These experimental data implied that miR-886-3p suppression mediated by ARE took part in the proliferation and metastasis of OSCC. This study can help elucidate the mechanism by which areca nut chewing contributes to the malignant transformation of oral epithelial cells.

Egr-1 mediates low-dose arecoline induced human oral mucosa fibroblast proliferation via transactivation of Wnt5a expression

Background

Arecoline is an alkaloid natural product found in the areca nut that can induce oral submucous fibrosis and subsequent development of cancer. However, numerous studies have shown that arecoline may inhibit fibroblast proliferation and prevent collagen synthesis.

Results

High doses of arecoline (> 32 μg/ml) could inhibit human oral fibroblast proliferation, while low doses of arecoline (< 16 μg/ml) could promote the proliferation of human oral fibroblasts. Wnt5a was found to be both sufficient and necessary for the promotion of fibroblast proliferation. Egr-1 could mediate the expression of Wnt5a in fibroblasts, while NF-κB, FOXO1, Smad2, and Smad3 did not. Treatment with siRNAs specific to Egr-1, Egr inhibitors, or Wnt5a antibody treatment could all inhibit arecoline-induced Wnt5a upregulation and fibroblast proliferation.

Conclusions

Egr-1 mediates the effect of low dose arecoline treatment on human oral mucosa fibroblast proliferation by transactivating the expression of Wnt5a. Therefore, Egr inhibitors and Wnt5a antibodies are potential therapies for treatment of oral submucosal fibrosis and oral cancer.

Oxidative-protective effect of nuclear receptor coactivator 7 on arecoline-induced endothelial-to-mesenchymal transition

OBJECTIVE

Overproduction of reactive oxygen species (ROS) has been implicated in inflammatory activities and tumorigenesis in oral submucous fibrosis (OSF). Nuclear receptor coactivator 7 (NCOA7) is capable of regulating cellular responses to ROS. The aim of this study was to investigate the expression of NCOA7 in endothelial cells and the role of NCOA7 in areca nut-induced endothelial-to-mesenchymal transition (EndMT).

STUDY DESIGN

Immunohistochemistry and immunofluorescence were used to detect the expression of NCOA7 in endothelia. Human umbilical vein endothelial cells (HUVECs) were treated with various dosages of arecoline (0, 5, 10, 20 μg/mL); then NCOA7 expression, the correlation of NCOA7 with EndMT, and the potential signaling were analyzed by using small interfering RNA (siRNA) transfection, reverse transcription polymerase chain reaction, Western blotting, and flow cytometry.

RESULTS

NCOA7 was significantly elevated in OSF tissues, as detected with immunohistochemistry and immunofluorescence. After arecoline treatment, NCOA7 expression and EndMT were induced in HUVECs. Transfection of HUVECs with si-NCOA7, which reduced 73% of NCOA7 expression, aggravated the arecoline-induced EndMT process. Inhibition of ROS markedly, but not completely, reverses this arecoline-induced EndMT in si-NCOA7 cells.

CONCLUSIONS

This study highlights NCOA7 as a potential target for therapeutic intervention to mediate EndMT via ROS species production.

Arecoline induces epithelial mesenchymal transition in HK2 cells by upregulating the ERK-mediated signaling pathway

Arecoline, a component of betel nuts, is a known carcinogen that causes oral cancers among those who chew betel nuts. Betel nut chewing is also associated with an increased risk of chronic kidney disease (CKD), but the role of arecoline in this association is unclear. This in vitro study investigates the effects of arecoline on cultured human kidney (HK2) cells. We observed that arecoline had no effect on cell viability but increased cell migration in a dose-dependent manner. Western blot analysis showed that arecoline treatment caused a dose-dependent decrease in E-cadherin expression and dose-dependent increases in N-cadherin, vimentin, α-SMA, and collagen expression; reverse transcriptase-polymerase chain reaction analysis revealed dose-dependent increases in α-SMA and collagen mRNA. Arecoline treatment upregulated the expression of phosphorylated extracellular signal-regulated kinase through epithelial mesenchymal transition and renal fibrosis in HK2 cells. These findings demonstrate that arecoline plays a role in inducing the epithelial mesenchymal transition and fibrogenesis in renal tubule cells and suggest that arecoline promotes the progression of CKD.

Metformin protects against mouse oocyte apoptosis defects induced by arecoline

OBJECTIVES

Arecoline is the main bioactive substance extracted from Areca catechu L, which has cell, neural and genetic toxicity. The function of arecoline in reproductive system has not been well explored.

MATERIALS AND METHODS

To investigate the toxic effects of arecoline on oocyte development, immunofluorescence staining, qPCR, Western blotting, sperm binding assays and in vitro fertilization were performed to evaluate oocyte meiosis competence and embryo development.

RESULTS

Our data revealed that arecoline exposure disrupts actin filament dynamics, spindle assembly and kinetochore-microtubule attachment stability in mouse oocytes, leading to aneuploidy and oocyte meiosis arrest. In addition, arecoline treatment disturbs the distribution of mitochondria, reduces ATP production and increases the level of oxidative stress, which ultimately induces oocyte apoptosis. Supplementation with metformin, a medicine for type 2 diabetes in the clinic, partially alleviates these damages.

CONCLUSIONS

Metformin has a protective effect on arecoline-induced mouse oocytes apoptosis.

Betel Nut Use in Vanuatu: Investigating Opportunities to Reduce Harms to Health

Background: Betel nut chewing is a public health concern in the Asia-Pacific region and is an emerging issue in Vanuatu. Despite the significant health risks associated with betel nut chewing, few interventions have been undertaken to reduce its harm. Objectives: To investigate betel nut use in Vanuatu and to identify opportunities to reduce its harm and possible interventions, framing the responses using the World Health Organization's MPOWER tobacco control model. Method: Qualitative research design, in the form of semi-structured interviews with ten participants with expertise in health, agriculture, education or non-communicable disease in Port Vila, Vanuatu during June 2017. Recorded interviews were transcribed verbatim, and a general inductive approach was used to identify key themes. Results: Participants reported a recent increase in betel nut use in Vanuatu due to the influence from Papua New Guinea and the Solomon Islands. To reduce the harm of betel nut use in Vanuatu, participants suggested policies and strategies that aligned with the MPOWER framework that could be adopted for betel nut control, including restricting cultivation and sale of betel nut in Vanuatu and using radio and existing community networks to reach people with messages about the dangers of betel nut use. Conclusion: Betel nut use may be growing in popularity in Vanuatu, where there are potential policy options to minimize harm. The MPOWER model for tobacco control may be a useful framework to help the Vanuatu government to deliver a comprehensive approach to reducing harm from betel nut use.

Investigating Betel Nut Use, Antecedents and Consequences: A Review of Literature

Background: Betel nut use is a public health issue in the Asia-Pacific region that is often neglected. To control betel nut use, understanding of the adverse effects of betel nut use and evidence-based policies and strategies is necessary. Objectives: This narrative review aims to characterize the current situation on betel nut use at a global level regarding the epidemiology, pharmacology and toxicology, health effects, treatment options, policies and strategies. Methods: We found 139 existing literature published between 1970-2019 on the Web of Science database and other technical documents to collate the most relevant information on betel nut use. Data were categorized into appropriate themes. Results: The literature demonstrates that there is a lack of up to date statistics on betel nut use. There is limited research on the effect of policies and strategies to control betel nut use. Conclusion: Betel nut-chewing countries should focus on understanding which populations chew betel nut and implement appropriate policies, educational and cessation programs to help control betel nut use.

Chemistry, metabolism and pharmacology of carcinogenic alkaloids present in areca nut and factors affecting their concentration

Areca Nut (AN), the seed of tropical palm tree Areca catechu, is a widely chewed natural product with estimated 600 million users across the world. Various AN products, thriving in the market, portray 'Areca nut' or 'Supari' as mouth freshener and safe alternative to smokeless tobacco. Unfortunately, AN is identified as a Group 1 human carcinogen by International Agency for Research on Cancer (IARC). Wide variation in the level of alkaloids, broadly ranging from 2 to 10 mg/gm dry weight, is observed in diverse variety of AN sold worldwide. For the first time, various factors influencing the formation of carcinogenic alkaloids in AN at various stages, including during the growth, processing, and storage of the nut, are discussed. Current review illustrates the mechanism of cancer induction by areca alkaloids in humans and also compiles dose-dependent pharmacology and toxicology data of arecoline, the most potent carcinogenic alkaloid in AN. Careful monitoring of the arecoline content in AN can potentially be used as a tool in product surveillance studies to identify the variations in characteristics of various AN sample sold worldwide. The article will help to generate public awareness and sensitize the government bodies to initiate campaigns against AN use and addiction.

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.

Arecoline-regulated ataxia telangiectasia mutated expression level in oral cancer progression

BACKGROUND

Ataxia telangiectasia mutated (ATM) regulates DNA repair and cell cycle. The present study analyzed arecoline-induced ATM expression during oral cancer progression.

METHODS

In vitro studies were performed using oral squamous cell carcinoma (OSCC) cell lines treated with arecoline to analyze cell response and ATM regulation. in vivo studies were performed using immunohistochemistry to detect ATM expression in normal, oral potentially malignant disorder (OPMD), and OSCC tissues.

RESULTS

Low-dose arecoline induced cell proliferation, ATM promoter activity, and DNA repair. High-dose arecoline induced cell cycle arrest, apoptosis, and DNA damage. ATM was overexpressed in OPMD tissues but was downregulated in OSCC tissues. ATM expression level was associated with the risk of developing dysplasia, buccal-OSCC, and with OSCC survival rate.

CONCLUSION

High ATM expression helps DNA repair mechanisms to maintain the cells in the OPMD stage, but low ATM expression causes DNA damage accumulation to increase cell malignancy.

Habit History in Oral Submucous Fibrosis: Have We Over Emphasized?

Aim: Correlation of habit duration and frequency with clinical grading and histopathologic grouping of oral submucous fibrosis (OSMF). Materials and methods: 48 patients with OSMF were included in the study. Detailed history of each patient, clinical profile and habit history were recorded. Biopsy was performed for histopathological correlation. All the findings were correlated with Kerr et al and Khanna and Andrade classification. Statistical Analysis: Kruskal-wallis test was performed to assess the correlation between the study findings. Results: Out of 48 OSMF cases majority were males. Maximum cases were in clinically and histopathologically respectively. Mouth opening was directly proportional with histopathological grouping as per Khanna et al. No correlation between frequency and habit duration with respect to different stages or severity of the OSMF was noted. Conclusion: Disease staging of OSMF clinically and histopathologically is not directly impacted by habit duration and frequency. Rather than habit centered history and management accordingly, more focus should be given to genetics and susceptibility of patient for OSMF development and progression.

CYP450-mediated mitochondrial ROS production involved in arecoline N-oxide-induced oxidative damage in liver cell lines

BACKGROUND

IARC has classified the betel nut as a human environmental carcinogen. Previous studies have found that arecoline (AR) is the major alkaloid present in the saliva of betel quid chewers. Saliva contains a large content of AR which has been further shown to cause mutation of oral mucosa cells, resulting in oral cancer. Whereas, to date, there are only few studies reported the hepatotoxicity associated with arecoline and betel nut chewing. Therefore, the main purpose of this study was to determine the toxic effects of AR and its oxidative metabolite, arecoline N-oxide (ARNO), in normal liver cell lines.

METHODS

The cytotoxic, genotoxic, and mutagenic effects were detected by crystal violet staining, alkaline comet assay, and Salmonella mutagenicity test, respectively. Measurement of intracellular reactive oxygen species (ROS) generation was determined using the H2-DCFDA assay.

RESULTS

Our results demonstrated that ARNO exerted higher cytotoxicity, DNA damage, and mutagenicity than its parent compound arecoline in liver cells. Antioxidants, such as N-acetylcysteine, Trolox, and penicillamine, strongly protected liver cells from ARNO-induced DNA damage and ROS production. Furthermore, co-treatment with Mito-TEMPO also effectively blocked ARNO-induced ROS production in liver cells. Besides antioxidants, co-treatment with 1-aminobenzotriazole and methimazole nearly completely suppressed ARNO-induced ROS production in liver cells.

CONCLUSIONS

Our data suggest that arecoline ingested from the habit of chewing betel quid can be primarily oxidized to ARNO, thereby enhancing its toxicity through increased ROS production. Considering the excellent protective effects of both mitochondria-targeted antioxidant and CYP450 inhibitor on ARNO-induced ROS production in liver cells, mitochondria CYP450-mediated metabolism of ARNO may be a key mechanism. Collectively, our results provide novel cellular evidence for the positive connection between habitual betel quid chewing and the risk for liver damage.

Evaluation of the toxic potential of arecoline toward the third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9

Arecoline is the key component of areca nut and has been suggested as a carcinogenic agent. In the present study, the third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9 were allowed to feed on a diet having 5, 10, 20, 40 and 80 μM arecoline for 24 h. After the completion of 24 h, the larvae were subjected to ONPG assay, X-gal staining, trypan blue exclusion test, oxidative stress markers, and apoptotic and comet assays. A dose-dependent increase in the β-galactosidase activity, tissue damage, glutathione-S-transferase (GST) activity, lipid peroxidation assay, monoamine oxidase (MAO), caspase-9 and 3, protein carbonyl content (PCC), apoptotic index, and DNA damage and decrease in glutathione (GSH) content, delta aminolevulinic acid dehydrogenase (δ-ALA-D), and acetylcholinesterase (AChE) activity were observed in the larvae exposed to 20, 40 and 80 μM arecoline. The results suggest that arecoline is toxic at 20, 40, and 80 μM toward the third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9 . Arecoline did not show any toxic effects at 5 and 10 μM.

Betel nut chewing and the risk of chronic kidney disease: evidence from a meta-analysis

PURPOSE

To investigate and quantify the potential association between betel nut chewing and the risk of chronic kidney disease (CKD).

METHODS

We searched five online databases including PubMed, EMBASE, ISI Web of Science, Wanfang and CNKI to identify observational studies that published prior to May, 1, 2017. The primary outcome was the association between betel nut chewing and CKD expressed as odds ratio (OR) and the corresponding 95% confidence interval (95%CI) after adjustment for other covariates. Meta-analysis was performed using RevMan 5.3 software; the leave-one-out sensitivity analysis was used to confirm the stability of drawn conclusion.

RESULTS

Five studies comprising a total of 10,562 CKD patients and 34,038 subjects without CKD that analyzed the relationship between betel nut chewing and CKD were included in our study; all the included studies were performed in Taiwan. After the adjustment for covariates, the combined adjusted ORs showed that betel nut used had 1.44 times higher risk to develop CKD compared with non-chewers (OR 1.44, 95%CI 1.08-1.92).

CONCLUSIONS

Betel nut chewing could significantly increase the risk of CKD, indicating that betel nut chewing may exist as an independent risk factor for CKD. Further investigation should be warranted.

7-Ketocholesterol induces ATM/ATR, Chk1/Chk2, PI3K/Akt signalings, cytotoxicity and IL-8 production in endothelial cells

Cardiovascular diseases (atherosclerosis, stroke, myocardiac infarction etc.) are the major systemic diseases of elder peoples in the world. This is possibly due to increased levels of oxidized low-density lipoproteins (oxLDLs) such as 7-ketocholesterol (7-KC) and lysophosphatidylcholine (LPC) that damage vascular endothelial cells, induce inflammatory responses, to elevate the risk of cardiovascular diseases, Alzheimer's disease, and age-related macular degeneration. However the toxic effects of 7-KC on endothelial cells are not known. In this study, 7-KC showed cytotoxicity to endothelial cells at concentrations higher than 10 µg/ml. 7-KC stimulated ATM/Chk2, ATR-Chk1 and p53 signaling pathways in endothelial cells. 7-KC also induced G0/G1 cell cycle arrest and apoptosis with an inhibition of Cyclin dependent kinase 1 (Cdk1) and cyclin B1 expression. Secretion and expression of IL-8 in endothelial cells were stimulated by 7-KC. 7-KC further induced intracellular ROS production as shown by increase in DCF fluorescence and Akt phosphorylation. LY294002 attenuated the 7-KC-induced apoptosis and IL-8 mRNA expression of endothelial cells. These results indicate that oxLDLs such as 7-KC may contribute to the pathogenesis of atherosclerosis, thrombosis and cardiovascular diseases by induction of endothelial damage, apoptosis and inflammatory responses. These events are associated with ROS production, activation of ATM/Chk2, ATR/Chk1, p53 and PI3K/Akt signaling pathways.

Thioctic acid in oral submucous fibrosis (India's disease) - A better tomorrow

Oral submucous fibrosis (OSMF), because of its common occurrence in Indian population is known as India's disease. Regardless of diagnostic and therapeutic developments, oral potentially malignant disorders (PMD) and cancers are disseminating at a distressing rate. There is this prerequisite for unrelenting determination to find out apt treatment options so that malignant transformation may be prevented and more so the prevailing morbidity and mortality. Considering the frequency with which oral submucous fibrosis undergoes malignant transformation with free radicals playing a major part, the role of antioxidants in general and thioctic acid also known as alpha lipoic acid (ALA) in particular need to be studied in these individuals. Previous few studies indicated the use of alpha lipoic acid in oral submucous fibrosis patients leading to improvement in signs and symptoms. So, it led us to set forth and propose probable role of thioctic acid in improving symptoms in these patients. As oral submucous fibrosis poses as a threat with its various signs and symptoms and as a potentially malignant disorder as well as considering the role of free radicals in malignant transformation, we proposed the possible mechanisms behind the commonest signs and symptoms in oral submucous fibrosis and role of alpha lipoic acid in managing these signs and symptoms.

Defining a global research and policy agenda for betel quid and areca nut

Betel quid and areca nut are known risk factors for many oral and oesophageal cancers, and their use is highly prevalent in the Asia-Pacific region. Additionally, betel quid and areca nut are associated with health effects on the cardiovascular, nervous, gastrointestinal, metabolic, respiratory, and reproductive systems. Unlike tobacco, for which the WHO Framework Convention on Tobacco Control provides evidence-based policies for reducing tobacco use, no global policy exists for the control of betel quid and areca nut use. Multidisciplinary research is needed to address this neglected global public health emergency and to mobilise efforts to control betel quid and areca nut use. In addition, future research is needed to advance our understanding of the basic biology, mechanisms, and epidemiology of betel quid and areca nut use, to advance possible prevention and cessation programmes for betel quid and areca nut users, and to design evidence-based screening and early diagnosis programmes to address the growing burden of cancers that are associated with use.

Lysophosphatidylcholine induces cytotoxicity/apoptosis and IL-8 production of human endothelial cells: Related mechanisms

Increased levels of oxidized low-density lipoprotein oxLDL) are shown to elevate the risk of cardiovascular diseases such as atherosclerosis, thrombosis, stroke, and myocardial infarction. This is possibly due to the toxic effects of oxLDLs on vascular cells. Various oxLDLs including lysophosphatidylcholine (LPC) and 7-ketocholesterol injure vascular endothelial cells and stimulate inflammatory reaction. However the toxicity of LPC on endothelial cells is not clear. In this study, human endothelial cells were exposed to LPC. Cytotoxicity was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Propidium iodide (PI) staining or PI/Annexin V dual staining flow cytometry were used to determine cell cycle progression and apoptosis. Reactive oxygen species (ROS) level was analyzed by DCFH-DA labeling flow cytometry. RNA and protein expression of endothelial cells was studied by reverse transcriptase-polymerase chain reaction and western blotting. IL-8 secretion was measured by enzyme-linked immunosorbant assay. LPC showed cytotoxicity to endothelial cells (>50 µg/ml). LPC induced cell cycle arrest and apoptosis with concomitant inhibition of cdc2 and cyclin B1 expression. LPC stimulated intracellular ROS production and ATM/Chk2, ATR/Chk1 and Akt activation. IL-8 expression and secretion in endothelial cells were induced by LPC. LPC-induced apoptosis, and IL-8 expression/secretion was attenuated by LY294002, a PI3K/Akt inhibitor. These results reveal that LPC is involved in the pathogenesis of atherosclerosis and vascular diseases by stimulation of inflammation and injury to endothelial cells. These events are related to ROS, ATM/Chk2, ATR/Chk2 and PI3K/Akt signaling. Understanding the toxic mechanisms of LPC is useful for future prevention and treatment atherosclerosis.

[Epidemiological investigation of chewing fresh or dried betel nut and oral mucosal disease]

OBJECTIVE

This study was conducted to investigate the effect of chewing fresh or dried betel nut on the inci-dence and canceration of oral mucosa disease in Haikou City in Hainan Province.

METHODS

Through a survey questionnaire, clinical examination, and regular follow-up, we collected clinical data from 1 722 cases and divided them into two groups, among which 704 of the afflicted people chew dried betel nut, whereas the other 1 018 chew fresh betel nut. The data were 
statistically analyzed using different variables which included age, number, time of onset of the disease, and the cancerous condition associated with common oral mucosa disease, including oral submucous fibrosis (OSF), oral leukoplakia (OLK), and oral Lichen planus (OLP).

RESULTS

1) The study found no significant difference in the prevalence of oral mucosa diseases between the dried betel nut group (n=704) and fresh betel nut group (n=1 018) among the 1 722 cases (P>0.05), but the peak age of oral mucosal disease was more advanced in the dried betel nut group (P<0.01). 2) The incidence within 5 years of OSF, OLK, OLP, and oral mucosa diseases in the dried betel nut group was significantly higher than that in the fresh betel nut group (P<0.01). 3) The incidence of cancer for oral mucosa disease in patients included in the dried betel nut group was significantly higher than that in the fresh betel nut group (P<0.01).

CONCLUSIONS

Chewing dried betel nut is more pathogenic and carcinogenic than chewing fresh betel nut. The extremely harmful components of the dried betel nut synergistically play a vital role in the occurrence and carcinogenesis of oral mucosal diseases.

Oral submucous fibrosis: A quantitative assessment of serum malondialdehyde, superoxide dismutase and correlation with clinical staging

BACKGROUND

Oral submucous fibrosis (OSMF) is a progressive disorder affecting the oral mucosa. OSMF predominantly seen in South-east Asian countries. There are some biochemicals parameters which are modify in oral submucous fibrosis; this alteration can be used as a tool for diseases progress and avert malignant transformation.

AIMS AND OBJECTIVES

The aim of this study is to evaluate the serum malondialdehyde (malondialdehyde [MDA]), and Superoxide dismutase (SOD) in oral sub mucous fibrosis cases and compare clinical stages.

MATERIALS AND METHODS

Thirty cases of clinical and histopathological established oral submucous fibrosis and thirty cases of nonsymptomatic features of oral submucous fibrosis preferred as controls. Venous blood was collected and separation of serum for estimation of MDA and SOD levels was done using an ultraviolet spectrophotometer.

STATISTICAL ANALYSIS

Data were analyzed using SPSS software using Student's t-test and Kruskal-Wallis ANOVA test.

RESULTS

Serum MDA levels were elevated when clinical staging increases, where as SOD levels were decreased when clinical stage increases when compared with control cases and it showed stastically significant.

CONCLUSION

Estimation of serum MDA and SOD in patients with OSMF, we can assess the degree of oxidative damage of the disease. This can be used as an early diagnostic tool for preventing malignant transformation of oral submucous fibrosis.

Limited mouth opening in oral submucous fibrosis: reasons, ramifications, and remedies

Limited mouth opening (LMO) in oral submucous fibrosis (OSF) has been attributed to both the submucosal and muscle fibrosis (MF). While reflectory trismus was proposed before as an auxiliary mechanism by another group, the stretch-mediated muscle damage (MSD), histopathological changes in blood vessels (such as endothelial dysfunction, endothelial hypertrophy, and endarteritis obliterans), and upregulated anaerobic isoforms of lactate dehydrogenase (LDH) have been proposed by us as complementary events leading to MF. Additionally, the amount of hypoxia-mediated upregulation of anaerobic isoforms of LDH determines the extent of MF. Radiotherapy (RT)-mediated release of reactive oxygen species causes vascular damage thereby worsening hypoxia. While the alteration in LDH levels secondary to hypoxia enhances fibrosis, RT worsens it. Oral squamous cell carcinoma occurring in the background of OSF is an absolute contraindication for RT as it augurs unfavorable prognosis. An algorithm to demonstrate this with evidence is clearly depicted. The role of HIF-1α in the progression of OSF and its malignant transformation, and the consideration of hyperbaric oxygen therapy as a therapeutic remedy in OSF are underscored.

Areca nut contributes to oral malignancy through facilitating the conversion of cancer stem cells

Oral cancer is one of the most frequent malignant diseases worldwide, and areca nut is a primary carcinogen causing this cancer in Southeast Asia. Previous studies to examine the effects of this carcinogen often used short-term and high-dose treatment of area nut extract as a research model, which do not recapitulate the conditions of patients with long-term and habitual use of this substance. To approach authentic mechanism of areca nut-induced oral carcinogenesis that occurs in human, we established four isogenic sublines of oral cells which were chronic exposed to areca nut extract. Without eliciting cytotoxicity or senescence, these four sublines cells exhibited significant increase in invasive ability, along with epithelial-mesenchymal transition. These cells also showed resistance to chemotherapeutic drug and irradiation, accompanying with the augmentation of ABCG2 protein efflux and increased ROS clearance. Moreover, these sublines possessed the characteristics of cancer stemness, as demonstrated by enriched CD24-/CD44+ and CD133+ sub-populations, enhanced spheroid cell formation, and induced expressions of pluripotent stemness regulators, including Gp96, Grp78, Slug, Sox9, Snail, and Foxc2. These stemness regulators were further shown up-regulations in oral cancer patients with areca nut-chewing habit, and were statistically correlated with CD44 expression, a stemness marker. In conclusion, our findings suggested that areca nut contributes to oral malignancy through facilitating the conversion of cancer stem cells. This study may further contribute to clinical applications in disease prevention, risk assessment or molecular therapeutics on areca nut- associated diseases.

p-Cresol affects reactive oxygen species generation, cell cycle arrest, cytotoxicity and inflammation/atherosclerosis-related modulators production in endothelial cells and mononuclear cells

Aims

Cresols are present in antiseptics, coal tar, some resins, pesticides, and industrial solvents. Cresol intoxication leads to hepatic injury due to coagulopathy as well as disturbance of hepatic circulation in fatal cases. Patients with uremia suffer from cardiovascular complications, such as atherosclerosis, thrombosis, hemolysis, and bleeding, which may be partly due to p-cresol toxicity and its effects on vascular endothelial and mononuclear cells. Given the role of reactive oxygen species (ROS) and inflammation in vascular thrombosis, the objective of this study was to evaluate the effect of p-cresol on endothelial and mononuclear cells.

Methods

EA.hy926 (EAHY) endothelial cells and U937 cells were exposed to different concentrations of p-cresol. Cytotoxicity was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5 -diphenyltetrazolium bromide (MTT) assay and trypan blue dye exclusion technique, respectively. Cell cycle distribution was analyzed by propidium iodide flow cytometry. Endothelial cell migration was studied by wound closure assay. ROS level was measured by 2′,7′-dichlorofluorescein diacetate (DCF) fluorescence flow cytometry. Prostaglandin F_2α (PGF_2α), plasminogen activator inhibitor-1 (PAI-1), soluble urokinase plasminogen activator receptor (suPAR), and uPA production were determined by Enzyme-linked immunosorbant assay (ELISA).

Results

Exposure to 100–500 µM p-cresol decreased EAHY cell number by 30–61%. P-cresol also decreased the viability of U937 mononuclear cells. The inhibition of EAHY and U937 cell growth by p-cresol was related to induction of S-phase cell cycle arrest. Closure of endothelial wounds was inhibited by p-cresol (>100 µM). P-cresol (>50 µM) also stimulated ROS production in U937 cells and EAHY cells but to a lesser extent. Moreover, p-cresol markedly stimulated PAI-1 and suPAR, but not PGF_2α, and uPA production in EAHY cells.

Conclusions

p-Cresol may contribute to atherosclerosis and thrombosis in patients with uremia and cresol intoxication possibly due to induction of ROS, endothelial/mononuclear cell damage and production of inflammation/atherosclerosis-related molecules.

The influence of monoamine oxidase variants on the risk of betel quid-associated oral and pharyngeal cancer

Betel quid (BQ) and areca nut (AN) (major BQ ingredient) are group I human carcinogens illustrated by International Agency for Research on Cancer and are closely associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. The primary alkaloid of AN, arecoline, can be metabolized via the monoamine oxidase (MAO) gene by inducing reactive oxygen species (ROS). The aim of this study was to investigate whether the variants of the susceptible candidate MAO genes are associated with OPMDs and oral and pharyngeal cancer. A significant trend of MAO-A mRNA expression was found in in vitro studies. Using paired human tissues, we confirmed the significantly decreased expression of MAO-A and MAO-B in cancerous tissues when compared with adjacent noncancerous tissues. Moreover, we determined that MAO-A single nucleotide polymorphism variants are significantly linked with oral and pharyngeal cancer patients in comparison to OPMDs patients [rs5953210 risk G-allele, odds ratio = 1.76; 95% confidence interval = 1.02-3.01]. In conclusion, we suggested that susceptible MAO family variants associated with oral and pharyngeal cancer may be implicated in the modulation of MAO gene activity associated with ROS.

Therapeutic interventions in oral submucous fibrosis: an experimental and clinical study

INTRODUCTION

Oral submucous fibrosis (OSF) is a chronic debilitating disease and premalignant condition of the oral cavity and is a serious public health issue in India and many parts of the world. The treatment is still elusive and empirical because of poorly understood etiopathogenesis, which is believed to be multifactorial including areca nut chewing, ingestion of chillies, genetic and immunologic processes, nutritional deficiencies, and many others. The present investigations was focused to understand the possible therapeutic interventions of anti-OSF agents in arecoline induced experimental in vitro model of OSF and clinical application of these anti-OSF agents in the restoration of various grade of the disease.

MATERIALS AND METHODS

The 127 subjects were selected from patients who visited the OPD of Department of Oral and Maxillofacial Surgery, Faculty of Dental Sciences, K.G. Medical University, Lucknow. Further the subjects were divided in two groups on the basis of clinical examination. Group-1 subjects showed presence of fibrosis bands in the labial and/or buccal mucosa, loss of elasticity, difficulty to open the mouth and had a habit chewing areca-nut in some form. Group-2 subjects had no habit of chewing areca-nut, were apparently healthy with no mucosal disorder. The samples were collected and were immediately transported to Indian Institute of Toxicology Research, Lucknow, for isolation and cultivation of primary cultures of mucosal fibroblast cells. Then isolation and cultivation of oral mucosal fibroblast, identification of non-cytotoxic doses of arecoline, real time PCR, immunocytochemistry, cytokine determination in culture cells, western blot analyses, functional activity of collagenase, lysyl oxidase enzyme activity, collagen beads assay, cyclooxygenase (COX-2) expression analysis was done.

RESULTS AND CONCLUSIONS

This study, shows that the reduction of phagocytic cells was strongly related to the arecoline levels in fibroblast culture when we exposed arecoline to normal oral mucosal cells (NOMC) and cells from OSF patient. An enhancement of phagocytic cells was observed following the pre exposure of cells to 1 μM dexamethasone, a glucocorticoids, In this study, histologic evidence is presented which supports the finding that COX-2 expression is upregulated in OSF specimens compared to normal oral submucosal cells. Strong immunostaining for COX-2 was detected in arecoline exposed NOMC and cells from OSF patient. Areca nut extract up-regulates prostaglandin production, cyclooxygenase-2 mRNA and protein expression of human oral keratinocytes. The number of phagocytic cells and phagocytic activity in cultured human oral fibroblasts from OSF site was lower than the fibroblasts from the normal regions of the same person.

Expression of a splice variant of CYP26B1 in betel quid-related oral cancer

Betel quid (BQ) is a psychostimulant, an addictive substance, and a group 1 carcinogen that exhibits the potential to induce adverse health effects. Approximately, 600 million users chew a variety of BQ. Areca nut (AN) is a necessary ingredient in BQ products. Arecoline is the primary alkaloid in the AN and can be metabolized through the cytochrome P450 (CYP) superfamily by inducing reactive oxygen species (ROS) production. Full-length CYP26B1 is related to the development of oral pharyngeal cancers. We investigated whether a splice variant of CYP26B1 is associated with the occurrence of ROS related oral and pharyngeal cancer. Cytotoxicity assays were used to measure the effects of arecoline on cell viability in a dose-dependent manner. In vitro and in vivo studies were conducted to evaluate the expression of the CYP26B1 splice variant. The CYP26B1 splice variant exhibited lower expression than did full-length CYP26B1 in the human gingival fibroblast-1 and Ca9-22 cell models. Increased expression of the CYP26B1 splice variant was observed in human oral cancer tissue compared with adjacent normal tissue, and increased expression was observed in patients at a late tumor stage. Our results suggested that the CYP26B1 splice variant is associated with the occurrence of BQ-related oral cancer.

HBO: a possible supplementary therapy for oral potentially malignant disorders

Oral potentially malignant disorders (OPMDs) are chronic inflammatory diseases in which cells suffer hypoxia referring to deprivation of adequate oxygen supply. Hyperbaric oxygen treatment (HBO), which can increase oxygen tension and delivery to oxygen-deficient tissue, is a supplementary therapy to improve or cure disorders involving hypoxia. Although the applications of HBO in wound healings, acute ischemic stroke, radiation-induced soft tissue injury and cancers are extensively reported, there are only few studies on their effect in OPMDs. Not only does HBO furnish oxygen-it also possesses potent anti-inflammatory properties. At the cellular level, HBO can decrease lymphocyte proliferation and promote apoptosis of fibroblasts. At the molecular level, it can decrease expression of HIF, ICAM-1, TNF-α, TGF-β, and IFN-γ, as well as increase vascular VEGF expression and angiogenesis. Thus, we hypothesize that HBO may contribute to treat OPMDs, including oral lichen planus, oral leukoplakia, and oral submucous fibrosis both at the cellular level and the molecular level, and that it would be a safe and inexpensive therapeutic strategy.

Arecoline is cytotoxic for human endothelial cells

BACKGROUND

Oral submucous fibrosis is a pre-malignant fibrotic condition caused by areca nut use and involves reduced mucosal vascularity. Arecoline is the principal areca nut alkaloid and is cytotoxic for epithelium and fibroblasts. Endothelial cell cycle arrest is reported on exposure to arecoline, as is cytotoxicity for endothelial-lung carcinoma hybrid cells. We here describe cytotoxicity for primary human endothelial cultures from seven separate donors.

MATERIALS AND METHODS

Human umbilical vein endothelial cells were exposed to increasing concentrations of arecoline and examined by: phase-contrast microscopy, haemocytometer counts, transmission electron microscopy, lactate dehydrogenase release and the methyl-thiazol-tetrazolium assay.

RESULTS

Vacuolation and detachment of endothelium were observed at and above arecoline concentrations of 333 μg/ml or more. Ultrastructural features of cellular stress were seen after 24-h treatment with 111 μg/ml arecoline and included reduced ribosomal studding of endoplasmic reticulum, increased autophagolysosomal structures, increased vacuolation and reduced mitochondrial cristae with slight swelling. Similar changes were seen at 4 h with arecoline at 333 μg/ml or above, but with more severe mitochondrial changes including increased electron density of mitochondrial matrix and greater cristal swelling, while by 24 h, these cells were frankly necrotic. Haemocytometer counts were paralleled by both lactate dehydrogenase release and the methyl-thiazol-tetrazolium assays.

CONCLUSIONS

Arecoline is cytotoxic via necrosis for endothelium, while biochemical assays indicate no appreciable cellular leakage before death and detachment, as well as no clear effect on mitochondrial function in viable cells. Arecoline toxicity may thus contribute to reduced vascularity in oral submucous fibrosis.