Up-regulation of matrix metalloproteinase-8 by betel quid extract and arecoline and its role in 2D motility

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 Review on Role of Arecoline and Its Metabolites in the Molecular Pathogenesis of Oral Lesions with an Insight into Current Status of Its Metabolomics

Areca nut consumption is a popular habit in Southeast Asian countries. One of the important biologically active alkaloids of areca nut is arecoline, which plays a role in mediating the development of several pathologies of the primary exposure site, the oral cavity. Studies on the metabolism of arecoline revealed the formation of several metabolites which themselves might be toxic. Moreover, polymorphisms in genes encoding enzymes involved in the metabolism of arecoline might predispose an organism towards the development of oral cancer. The present review tries to accumulate all the relevant existing literature and then elucidate the molecular mechanism by which arecoline plays a role in the development of oral submucous fibrosis and oral cancer. Existing information regarding arecoline metabolism, enzymes involved in the metabolic process and biological effects of the metabolites of arecoline have also been compiled and compared to study the toxicity of metabolites with its parent compound arecoline and whether they play any role in the pathogenesis of oral cancer mediated by areca nut consumption. A repertoire of molecular targets has come up in the discussion whose expression profile is perturbed by arecoline. Construction of induction cascade from existing literature has given an idea about the process of molecular pathogenesis. The summarized and analysed data can help to determine the molecular mechanism and drug targets, which in turn could be helpful in the prevention or treatment of these pathological conditions. It also brings into light areas where further research needs to be directed.

The Role of MMP8 in Cancer: A Systematic Review

Matrix metalloproteinases (MMPs) have traditionally been considered as tumor promoting enzymes as they degrade extracellular matrix components, thus increasing the invasion of cancer cells. It has become evident, however, that MMPs can also cleave and alter the function of various non-matrix bioactive molecules, leading to both tumor promoting and suppressive effects. We applied systematic review guidelines to study MMP8 in cancer including the use of MMP8 as a prognostic factor or as a target/anti-target in cancer treatment, and its molecular mechanisms. A total of 171 articles met the inclusion criteria. The collective evidence reveals that in breast, skin and oral tongue cancer, MMP8 inhibits cancer cell invasion and proliferation, and protects patients from metastasis via cleavage of non-structural substrates. Conversely, in liver and gastric cancers, high levels of MMP8 worsen the prognosis. Expression and genetic alterations of MMP8 can be used as a prognostic factor by examination of the tumor and serum/plasma. We conclude, that MMP8 has differing effects on cancers depending on their tissue of origin. The use of MMP8 as a prognostic factor alone, or with other factors, seems to have potential. The molecular mechanisms of MMP8 in cancer further emphasize its role as an important regulator of bioactive molecules.

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 Promotes Migration of A549 Lung Cancer Cells through Activating the EGFR/Src/FAK Pathway

Arecoline is the primary alkaloid in betel nuts, which are known as a risk factor for oral submucosal fibrosis and oral cancer. Lung cancer is a severe type of carcinoma with high cell motility that is difficult to treat. However, the detailed mechanisms of the correlation between Arecoline and lung cancer are not fully understood. Here, we investigated the effect of Arecoline on migration in lung cancer cell lines and its potential mechanism through the muscarinic acetylcholine receptor 3 (mAChR3)-triggered EGFR/Src/FAK pathway. Our results indicate that different concentrations of Arecoline treatment (10 µM, 20 µM, and 40 µM) significantly increased the cell migration ability in A549 and CL1-0 cells and promoted the formation of the filamentous actin (F-actin) cytoskeleton, which is a crucial element for cell migration. However, migration of H460, CL1-5, and H520 cell lines, which have a higher migration ability, was not affected by Arecoline treatment. The EGFR/c-Src/Fak pathway, which is responsible for cell migration, was activated by Arecoline treatment, and a decreased expression level of E-cadherin, which is an epithelial marker, was observed in Arecoline-treated cell lines. Blockade of the EGFR/c-Src/Fak pathway with the inhibitors of EGFR (Gefitinib) or c-Src (Dasatinib) significantly prevented Arecoline-promoted migration in A549 cells. Gefitinib or Dasatinib treatment significantly disrupted the Arecoline-induced localization of phospho-Y576-Fak during focal adhesion in A549 cells. Interestingly, Arecoline-promoted migration in A549 cells was blocked by a specific mAChR3 inhibitor (4-DAMP) or a neutralizing antibody of matrix metalloproteinase (MMP7 or Matrilysin). Taken together, our findings suggest that mAChR3 might play an essential role in Arecoline-promoted EGFR/c-Src/Fak activation and migration in an A549 lung cancer cell line.

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.

ZEB1 as an indicator of tumor recurrence for areca quid chewing-associated oral squamous cell carcinomas

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the sixth most prevalent malignancy worldwide and the third most common cancer in developing nation. Most OSCC patients relapse within months after receiving treatment. Therefore, searching the biomarkers of recurrence is urgently required to improve OSCC patient survival.

METHODS

We set out to explore whether expression of ZEB1 could be triggered in oral epithelial cells (SG and FaDu) by arecoline in vitro. Control and ZEB1-knockdown arecoline-stimulated SG and FaDu were subjected to migration/invasiveness/anchorage-independent growth assay. Primary and recurrent OSCC tissues from areca quid chewers were analyzed using real-time RT-PCR analysis for ZEB1 expression.

RESULTS

Arecoline led to dose-dependent elevation of ZEB1 expression in SG and FaDu cells. Downregulation of ZEB1 by lentiviral infection significantly reversed arecoline-induced oncogenicity including migration ability, cell invasiveness, and anchorage-independent growth in SG and FaDu cells. Clinically, the level of ZEB1 expression was higher in recurrent OSCC tumor samples but lower in primary lesions.

CONCLUSIONS

Targeting ZEB1 might offer a new strategy for the treatment of OSCC patients. ZEB1 can serve as a progression and relapse marker in OSCC patients.

Genomic alterations in breast cancer patients in betel quid and non betel quid chewers

Betel Quid (BQ) chewing independently contributes to oral, hepatic and esophageal carcinomas. Strong association of breast cancer risk with BQ chewing in Northeast Indian population has been reported where this habit is prodigal. We investigated genomic alterations in breast cancer patients with and without BQ chewing exposure. Twenty six BQ chewers (BQC) and 17 non BQ chewer (NBQC) breast cancer patients from Northeast India were analyzed for genomic alterations and pathway networks using SNP array and IPA. BQC tumors showed significantly (P<0.01) higher total number of alterations, as compared with NBQC tumors, 48±17% versus 32±25 respectively. Incidence of gain in fragile sites in BQC tumors were significantly (P<0.001) higher as compared with NBQC tumors, 34 versus 23% respectively. Two chromosomal regions (7q33 and 21q22.13) were significantly (p<0.05) associated with BQC tumors while two regions (19p13.3–19p12 and 20q11.22) were significantly associated with NBQC tumors. GO terms oxidoreductase and aldo-keto reductase activity in BQC tumors in contrast to G-protein coupled receptor protein signaling pathway and cell surface receptor linked signal transduction in NBQC tumors were enriched in DAVID. One network “Drug Metabolism, Molecular Transport, Nucleic Acid Metabolism” including genes AKR1B1, AKR1B10, ETS2 etc in BQC and two networks “Molecular Transport, Nucleic Acid Metabolism, Small Molecule Biochemistry” and “Cellular Development, Embryonic Development, Organismal Development” including genes RPN2, EMR3, VAV1, NNAT and MUC16 etc were seen in NBQC. Common alterations (>30%) were seen in 27 regions. Three networks were significant in common regions with key roles of PTK2, RPN2, EMR3, VAV1, NNAT, MUC16, MYC and YWHAZ genes. These data show that breast cancer arising by environmental carcinogens exemplifies genetic alterations differing from those observed in the non exposed ones. A number of genetic changes are shared in both tumor groups considered as crucial in breast cancer progression.

Association of betel nut with carcinogenesis: revisit with a clinical perspective

Betel nut (BN), betel quid (BQ) and products derived from them are widely used as a socially endorsed masticatory product. The addictive nature of BN/BQ has resulted in its widespread usage making it the fourth most abused substance by humans. Progressively, several additives, including chewing tobacco, got added to simple BN preparations. This addictive practice has been shown to have strong etiological correlation with human susceptibility to cancer, particularly oral and oropharyngeal cancers.

The PUBMED database was searched to retrieve all relevant published studies in English on BN and BQ, and its association with oral and oropharyngeal cancers. Only complete studies directly dealing with BN/BQ induced carcinogenesis using statistically valid and acceptable sample size were analyzed. Additional relevant information available from other sources was also considered.

This systematic review attempts to put in perspective the consequences of this widespread habit of BN/BQ mastication, practiced by approximately 10% of the world population, on oral cancer with a clinical perspective. BN/BQ mastication seems to be significantly associated with susceptibility to oral and oropharyngeal cancers. Addition of tobacco to BN has been found to only marginally increase the cancer risk. Despite the widespread usage of BN/BQ and its strong association with human susceptibility to cancer, no serious strategy seems to exist to control this habit. The review, therefore, also looks at various preventive efforts being made by governments and highlights the multifaceted intervention strategies required to mitigate and/or control the habit of BN/BQ mastication.

Downregulation of Ches1 and other novel genes in oral cancer cells chronically exposed to areca nut extract

BACKGROUND

This study was undertaken to identify the genes in response to areca nut extract, a potential carcinogen of oral cancer.

METHODS

Two oral cancer sublines chronically treated with areca nut extract were established. Methods such as microarray and immunohistochemistry were used to screen and validate the genes' altered expressions in areca nut extract-sublines or in cancer tissues.

RESULTS

A total of 35 genes were differentially expressed in both sublines. Several functional pathways were significantly altered. Six genes were confirmed over 2-fold of changes, including Ches1. Functional analyses showed that overexpression of Ches1 suppressed cell growth and arrested cells in the G2/M phase. Consistently, this gene has reduced expression in 52% of oral cancer tissues, which was significantly correlated with the areca nut chewing habit of patients (p = .04).

CONCLUSION

We identified 35 candidates and validated 6 genes that may be associated with areca nut-induced oral cancer. Loss of Ches1 may be attributed to areca nut extract-induced oral carcinogenesis.

Possible mechanism of betel-quid-extract-induced expression of matrix metalloproteinase-2

BACKGROUND/PURPOSE

Betel quid extract (BQE) has been demonstrated to induce matrix metalloproteinase (MMP)-2 expression. This study aimed to establish the possible mechanism involved in this event.

METHODS

Western blotting, reverse-transcription polymerase chain reaction, and gelatin zymography were used to study the expression level of MMP-2. LY294002, PD98059, U0126, N-acetyl-L-cysteine, SB203580, SP600125, and Bay 11-7082 were used to pretreat OECM-1 cells before BQE treatment and MMP-2 detection.

RESULTS

OECM-1 cells were subjected to short-term (10 minutes) or long-term (24 hours) BQE treatment (designated as SBT and LBT, respectively), and we found that both treatments increased MMP-2 protein and extracellular signal-regulated kinase (ERK) phosphorylation levels in a concentration- and time-dependent manner. LBT also increased MMP-2 mRNA level. LBT-induced MMP-2 secretion was not inhibited by PD98059 (up to 50 μM) when ERK was effectively blocked, but was attenuated by LY294002 (0-10 μM) in a concentration-dependent manner. This LBT effect was inhibited strongly by SB203580 (10 μM), SP600125 (10 μM), and Bay 11-7082 (10 μM) and mildly by N-acetyl-L-cysteine (5 mM), but not by U0126 (10 μM).

CONCLUSION

Both SBT and LBT upregulate MMP-2 expression, and LBT-induced MMP-2 expression might be mediated by phosphoinositide 3-kinase, p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, and nuclear factor-κB, and to a lesser extent, by reactive oxygen species, rather than by ERK.

Oral squamous cell cancer: early detection and the role of alcohol and smoking

Objective

Oral squamous cell carcinoma has a remarkable incidence worldwide and a fairly onerous prognosis, encouraging further research on factors that might modify disease outcome.

Data sources

A web-based search for all types of articles published was initiated using Medline/Pub Med, with the key words such as oral cancer, alcohol consumption, genetic polymorphisms, tobacco smoking and prevention. The search was restricted to articles published in English, with no publication date restriction (last update 2010).

Review Methods

In this review article, we approach the factors for a cytologic diagnosis during OSCC development and the markers used in modern diagnostic technologies as well. We also reviewed available studies of the combined effects of alcohol drinking and genetic polymorphisms on alcohol-related cancer risk.

Results

The interaction of smoking and alcohol significantly increases the risk for aero-digestive cancers. The interaction between smoking and alcohol consumption seems to be responsible for a significant amount of disease.

Conclusion

Published scientific data show promising pathways for the future development of more effective prognosis. There is a clear need for new prognostic indicators, which could be used in diagnostics and, therefore a better selection of the most effective treatment can be achieved.

The role of matrix metalloproteinases in regulating neuronal and nonneuronal cell invasion into PEGylated fibrinogen hydrogels

Injured peripheral nerve tissue could benefit from biomaterial nerve guidance conduits (NGCs) that are designed to promote neuronal regeneration. Nerve regeneration is a complex multi-step process that involves the remodeling of the ECM surrounding the regenerating neural tissue. Hydrogel biomaterials have been used as provisional matrices to regulate this regeneration process by providing the desired physical properties and controllable degradation characteristics. The purpose of this investigation was to understand the mechanism by which nerve cells penetrate into a hydrogel made from PEGylated fibrinogen. In this context, the dorsal root ganglion (DRG) assay was used as an in vitro model to study the cellular invasion behavior of both neural and nonneuronal cells. Our hypothesis stipulated that DRG cells employ matrix metalloproteinases (MMPs) in order to degrade the dense hydrogel matrix and penetrate the biomaterial. Three dimensional (3D) DRG-hydrogel constructs were cultured with MMP inhibitors (MMPi) and the effect of the inhibitors on DRG cell outgrowth was investigated. We also examined the effect of inhibitors on two dimensional (2D) DRG cell outgrowth on PEGylated fibrinogen hydrogels and on tissue culture polystyrene (TCP). Our results demonstrate that DRG cell outgrowth into and onto PEGylated fibrinogen hydrogels was inhibited by MMPi and that the outgrowth characteristics was dependent on the type of inhibitor and its concentration. MMP-3i and MMP-8i decreased both neuronal and nonneuronal outgrowth, where MMP-3i had a stronger inhibitory effect on nonneuronal cells. MMP-2/9i, on the other hand, affected the neuronal outgrowth much more than the others. We concluded that MMPs play a central role in the process of DRG cell penetration into PEGylated fibrinogen hydrogels and may also regulate the adhesion, migration and elongation of neuronal cells on the surface of these hydrogel biomaterials.

Recent advances in Oral Oncology 2007: epidemiology, aetiopathogenesis, diagnosis and prognostication

This paper provides a synopsis of the main papers on epidemiology, diagnosis and prognosis of oral and oropharyngeal squamous cell carcinoma (OSCC) and head and neck SCC (HNSCC) published in 2007 in Oral Oncology - an international interdisciplinary journal which publishes high quality original research, clinical trials and review articles, and all other scientific articles relating to the aetiopathogenesis, epidemiology, prevention, clinical features, diagnosis, treatment and management of patients with neoplasms in the head and neck, and orofacial disease in patients with malignant disease.

Upregulation of matrix metalloproteinase-1 (MMP-1) expression in oral carcinomas of betel quid (BQ) users: roles of BQ ingredients in the acceleration of tumour cell motility through MMP-1

Matrix metalloproteinases (MMPs) are commonly expressed in carcinomas including oral squamous cell carcinomas (OSCCs). On the other hand, some evidences suggested that ingredients of betel quid (BQ) inhibit the activity and/or expression of some MMPs thought to be the pathogenesis of oral submucous fibrosis. This study was to analyse whether MMP-1 expression is inhibited in OSCC specimens from BQ users and in cell lines survived from the challenge of BQ ingredients. We found that MMP-1 mRNA was expressed in all the tested 27 OSCC. Levels of MMP-1 mRNA and protein were significantly elevated in the tested five OSCC specimens than in their adjacent tissues (P<0.001 and 0.05, respectively). Esophageal carcinoma (CE81T/VGH) and OSCC (OECM-1) cell lines survived from the cytotoxic BQ extract (BQE) and arecoline selection process were found to express higher MMP-1 mRNA and protein levels, or to exhibit a significant acceleration of two-dimensional (2D) motility than their non-selected parental cells. The enhanced motility was further demonstrated to be specifically and significantly inhibited by the MMP-1 neutralizing antibody and/or by the transfection of an MMP-1 specific antisense oligodeoxynucleotide. These results suggest that in some carcinomas of the upper aerodigestive tract, BQ usage may upregulate MMP-1 expression in the survived tumour cells, and increase their mobility in an MMP-1-dependent manner.