Biomedical subjects

Jiiang-Huei Jeng

Publications and source records attributed to Jiiang-Huei Jeng.

At least 19 recordsLinked to original sources

PubMed2006

Induction of necrosis and apoptosis to KB cancer cells by sanguinarine is associated with reactive oxygen species production and mitochondrial membrane depolarization.

Sanguinarine is a benzopheanthridine alkaloid present in the root of Sanguinaria canadensis L. and Chellidonium majus L. In this study, sanguinarine (2 and 3 microM) exhibited cytotoxicity to KB cancer cells by decreasing MTT reduction to 83% and 52% of control after 24-h of exposure. Sanguinarine also inhibited the colony forming capacity (>52-58%) and growth of KB cancer cells at concentrations higher than 0.5-1 microM. Short-term exposure to sanguinarine (>0.5 microM) effectively suppressed the adhesion of KB cells to collagen and fibronectin (FN). Sanguinarine (2 and 3 microM) induced evident apoptosis as indicated by an increase in sub-G0/G1 populations, which was detected after 6-h of exposure. Only a slight increase in cells arresting in S-phase and G2/M was noted. Induction of KB cell apoptosis and necrosis by sanguinarine (2 and 3 microM) was further confirmed by Annexin V-PI dual staining flow cytometry and the presence of DNA fragmentation. The cytotoxicity by sanguinarine was accompanied by an increase in production of reactive oxygen species (ROS) and depolarization of mitochondrial membrane potential as indicated by single cell flow cytometric analysis of DCF and rhodamine fluorescence. NAC (1 and 3 mM) and catalase (2000 U/ml) prevented the sanguinarine-induced ROS production and cytotoxicity, whereas dimethylthiourea (DMT) showed no marked preventive effect. These results suggest that sanguinarine has anticarcinogenic properties with induction of ROS production and mitochondrial membrane depolarization, which mediate cancer cell death.

Acetylcysteine↗

PubMed2006

Antiplatelet effect of sanguinarine is correlated to calcium mobilization, thromboxane and cAMP production.

Sanguinarine is a plant alkaloid present in the root of Sanguinaria canadensis and Poppy fumaria species. Sanguinarine has been used as an antiseptic mouth rinse and a toothpaste additive to reduce dental plaque and gingival inflammation. In this study, we investigated the antiplatelet effects of sanguinarine, aiming to extend its potential pharmacological applications. Sanguinarine inhibited platelet aggregation induced by arachidonic acid (AA), collagen, U46619 and sub-threshold concentration of thrombin (0.05 U/ml) with IC(50) concentrations of 8.3, 7.7, 8.6 and 4.4 microM, respectively. Sanguinarine (5-10 microM) inhibited 10-31% of platelet TXB(2) production, but not platelet aggregation induced by higher concentration of thrombin (0.1 U/ml). SQ29548, a thromboxane receptor antagonist, inhibited the AA-induced platelet aggregation but not TXB(2) production. Sanguinarine suppressed cyclooxygenase-1 (COX-1) activity (IC(50)=28 microM), whereas its effect on COX-2 activity was minimal. Sanguinarine (8, 10 microM) further inhibited the AA-induced Ca(2+) mobilization by 27-62%. In addition, SQ22536, an adenylate cyclase inhibitor, attenuated the inhibitory effect of sanguinarine toward AA-induced platelet Ca(2+) mobilization and aggregation. These results suggest that sanguinarine is a potent antiplatelet agent, which activates adenylate cyclase, inhibits platelet Ca(2+) mobilization, TXB(2) production as well as suppresses COX-1 enzyme activity. Sanguinarine may have therapeutic potential for treatment of cardiovascular diseases related to platelet aggregation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed2006

Toxic and metabolic effect of sodium butyrate on SAS tongue cancer cells: role of cell cycle deregulation and redox changes.

Butyrate is a metabolite produced by oral and colonic microorganism. Butyrate has been shown to reduce colon cancer, whereas its role in oral carcinogenesis is not clear. Butyrate concentration in dental plaque and saliva ranged from 0.2 to 16 mM. In this study, we found that sodium butyrate inhibited the growth of SAS tongue cancer cells by 32% and 53% at concentrations of 1 and 2mM, respectively. Low concentrations of sodium butyrate (1-8mM) induced G0/G1 cell cycle arrest of SAS cells, whereas concentrations of 4-16 mM elicited G2/M arrest and a slight increase in apoptotic cell populations. These events were concomitant with induction of intracellular reactive oxygen species (ROS) production. An elevation in p21 mRNA and protein level was noted in SAS cells by sodium butyrate. On the contrary, a decline of cyclin Bl, cdc2 and cdc25C mRNA and protein expression in SAS cells was found after exposure to sodium butyrate. In addition, no evident increase in cdc2 inhibitory phosphorylation was found in sodium butyrate-treated SAS cancer cells. Inclusion of N-acetyl-l-cysteine (NAC) (3mM), catalase (1000 U/ml) and dimethylthiourea (DMT, 5mM), and also SOD (500 U/ml) attenuated the sodium butyrate-induced ROS production in SAS cells. However, they were not able to prevent the cell cycle arrest, apoptosis and growth inhibition in SAS cells induced by 1, 2 and 16 mM of sodium butyrate. These results indicate that sodium butyrate is toxic and inhibits the tongue cancer cell growth via induction of cell cycle arrest and apoptosis. Sodium butyrate mediates these events by mechanisms additional to ROS production.

Apoptosis↗

PubMed2006

Carcinoma and dysplasia in oral leukoplakias in Taiwan: prevalence and risk factors.

OBJECTIVES: The issue of existence of malignancy within oral leukoplakia has seldom been addressed in Taiwan. The aims of this study were to investigate the prevalence of carcinoma and dysplasia within oral leukoplakia at the time of clinical diagnosis and to identify the associated risk factors in Taiwan. STUDY DESIGN: The prevalence rate of malignancy and dysplasia in 1046 oral leukoplakias at a university hospital was calculated. Univariate and multivariate analyses by the Mantel-Haenszel method and multiple logistic regression model were performed to examine risk factors associated with the presence of carcinoma and dysplasia within the lesions. RESULTS: The prevalence rate of carcinoma was 12.9%. The relative risks for the presence of malignancy in leukoplakias on the tongue/floor of mouth and with nonhomogeneous appearance were 2.72- and 28.13-fold by multivariate logistic regression analysis, when compared with those on buccal mucosa and lesions having homogeneous surface (both P < .05). In contrast, patients who both smoked and chewed betel quid had a significantly lower risk for carcinoma than the abstainers (P < .05). A synergistic effect between the 2 major risk factors of clinical appearance and lesion site was evident. Nonhomogeneous leukoplakia on tongue/floor of mouth had a 43.10-fold higher risk compared to homogeneous lesions located on buccal mucosa or other sites (P < .05). However, homogeneous leukoplakia in buccal mucosa or other sites of the oral cavity still had the possibility of having carcinoma within the lesion. The prevalence of dysplasia was 45.6% among the noncancerous leukoplakias with risk factors similar to those for carcinoma. CONCLUSIONS: Our results demonstrate that some leukoplakias contain a malignant component. Lesions with certain features are more prone to carcinoma, but no clinical attributes can bring certitude. Therefore, all oral leukoplakias should be submitted to microscopic analysis before any definite treatment or long-term follow-up.

Adult↗

PubMed2006

Prolonged exposure to arecoline arrested human KB epithelial cell growth: regulatory mechanisms of cell cycle and apoptosis.

Arecoline, the main areca alkaloid in betel quid (BQ), is reported to have cytotoxic, genotoxic, and mutagenic effects in various cells. It shows strong correlation to the incidence of oral submucous fibrosis, leukoplakia, and oral cancer. To clarify the role of arecoline in BQ-induced carcinogenesis, primary human gingival keratinocyes (GK) and human KB epithelial cells were used for studying the molecular mechanisms of arecoline-mediated cell cycle deregulation for comparison. After 24 h of exposure, arecoline (0.2-0.8 mM) inhibited KB cell growth in a dose- and time-dependent manner with a reduction in cell number by 27-37 and 37-58%, respectively, as determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. Incubation of KB cells with arecoline (0.1-0.4 mM) caused late-S and G2/M phases' cell cycle arrest. Western blot analysis revealed that arecoline induced cyclin Bl, Wee 1, and phosphorylated cdc2 protein levels whereas it declined p21 protein expression in KB cancer cells. Nevertheless, arecoline induced p21, but decreased cdc2 and cyclin B1 protein levels in GK. We demonstrated that higher concentrations of arecoline (0.2-1.2 mM) induced both cell necrosis and apoptosis as detected by DNA fragmentation and Annexin V-PI staining after long-term (48 h) treatment. Our results suggest that differential regulation of S and/or G2/M cell cycle-related proteins in the GK and KB cells play a crucial role in different stages of BQ-mediated carcinogenesis.

Apoptosis↗

PubMed2006

Treatment of pulp floor and stripping perforation by mineral trioxide aggregate.

Mineral trioxide aggregate (MTA) has been widely used to repair various kinds of tooth perforations, but its use for obturation of the entire root canal has not been reported. We report two cases of tooth perforation successfully repaired with MTA. The first patient was a 78-year-old male with calcified canal and pulp floor perforation in the left maxillary first premolar. After bypass of the calcified palatal canal, both buccal and palatal canals were filled with gutta percha, and the pulp floor perforation was repaired with MTA. Clinical success with no evident radicular lesion was found at the 18-month follow-up. The second patient was a 51-year-old female with a stripping perforation in a C-shaped root canal of the right mandibular second molar detected after removal of a post. Following root canal debridement and calcium hydroxide therapy to control inflammation at the stripping perforation site, apical and furcation bone healing were observed by radiographic examination. The stripping perforation was repaired by obturation of the entire C-shaped root canal with MTA. Observation at the 9-month follow-up revealed bone healing without any clinical symptoms and signs. These cases suggest that MTA is an alternative root canal obturation material for treatment of stripping perforation in a C-shaped root canal and for repair of pulp floor perforation.

Aged↗

PubMed2006

Signaling mechanism of thrombin-induced gingival fibroblast-populated collagen gel contraction.

1.--Thrombin is activated during gingival tissue injury and inflammation. Thrombin (platelet)-rich plasma has been used for periodontal regeneration with success. Thrombin and other bacterial proteases also affect the functions of adjacent periodontal cells via stimulation of protease-activated receptors (PARs). 2.--We noted that thrombin (0.1-2 U ml(-1)), human, and frog PAR-1 agonist peptide (20-240 microM) induced the gingival fibroblast (GF)-populated collagen gel contraction within 2 h of exposure. However, PAR-2, PAR-3, and PAR-4 agonist peptide (20-240 microM) showed little effect on collagen gel contraction. U73122 (phospholipase C inhibitor) and 2-APB (IP3 antagonist) were effective in inhibition of GF contraction. 3.--Thrombin-induced GF contraction was inhibited by 5 mM EGTA (an extracellular calcium chelator) and verapamil (an L-type calcium channel blocker). In addition, W7 (10 and 25 microM, a calcium/calmodulin (CaM) inhibitor), ML-7 (50 microM, myosin light chain kinase (MLCK) inhibitor), and HA1077 (100 microM, Rho kinase inhibitor) completely inhibited the thrombin-induced collagen gel contraction. Thrombin also induced the phosphorylation of ERK1/ERK2 and elevated the Rho-GTP levels in GF. 4.--However, U0126 only partially inhibited the thrombin-induced GF contraction. Similarly, wortmannin (100 nM), LY294002 (20 microM) (two PI3K inhibitor) and genistein also showed partial inhibition. Moreover, NAC was not able to suppress the GF contraction, as supported by the slight decrease in reactive oxygen species production in GF by thrombin. 5.--Thrombin also stimulated metalloproteinase-2 (MMP-2) and MMP-3 production in GF. But addition of GM6001 or 1,10-phenanthroline, two MMP inhibitors, could not inhibit the thrombin-induced GF contraction. 6.--These results indicate that thrombin is crucial in the periodontal inflammation and wound healing by promoting GF contraction. This event is mainly mediated via PAR-1 activation, PLC activation, extracellular calcium influx via L-type calcium channel, and the calcium/CaM-MLCK and Rho kinase activation pathway.

Calcium↗

PubMed2006

Abnormal gastroesophageal flap valve is highly associated with gastroesophageal reflux disease among subjects undergoing routine endoscopy in Taiwan.

OBJECTIVE: Gastroesophageal flap valve (GEFV) grade predicts severe gastroesophageal reflux disease in Caucasians, but its role in other populations is unclear. This study evaluated the significance of endoscopic grading of the GEFV in Taiwanese subjects. METHODS: Five hundred and six consecutive patients undergoing routine check-ups at the National Taiwan University Hospital were enrolled. Symptoms of upper gastrointestinal disease and endoscopic severity of esophageal mucosal injury were correlated to GEFV grades according to the Hill classification. RESULTS: The frequency of abnormal valves (Hill grades III or IV) was 27.3%. Of these, 42.7% had erosive esophagitis (EE). The majority of patients with EE were classified as Los Angeles grades A and B (79.7 and 16.9%, respectively). The prevalence of EE, hiatal hernia and, to a lesser degree, non-erosive reflux disease, increased with altered GEFV. Patients with abnormal valves were younger and more likely to be male, overweight, and to have atypical and extraesophageal symptoms. CONCLUSIONS: Taiwanese patients with abnormal GEFVs share similar characteristics and risk factors with the patients who have EE. Endoscopic grading of the GEFV is highly associated with GERD, and in particular EE, in subjects undergoing routine endoscopy.

Esophagitis↗

PubMed2005

Univariate and multivariate analysis of prognostic significance of betel quid chewing in squamous cell carcinoma of buccal mucosa in Taiwan.

BACKGROUND AND OBJECTIVES: While betel quid (BQ) chewing is clearly the most avoidable risk factor of squamous cell carcinoma of buccal mucosa (BMSCC), little is known about the influence of this habit on the prognosis of BMSCC. METHODS: We surveyed 280 patients with BMSCC who were treated during an 8-year period in a cohort study to assess the independent predictive value of pretreatment BQ chewing habit on the prognosis by univariate and multivariate analysis. RESULTS: We found by univariate analysis that sex, age, clinical stage, smoking, and BQ chewing significantly affected the patients' prognosis and only age, clinical stage, and BQ chewing had significant influence on prognosis by multivariate analysis (P < 0.05). Further analysis revealed that the prognostic effect of BQ chewing changed in a dose- and time-dependent manner. The risk of death was 31.4-fold higher in heavy user (duration >30 years, daily consumption >30 quids, age of start <20 years old) when compared to those who chewed BQ to a milder degree (duration <10 years, daily consumption <15 quids, age of start > or =20 years old ) (P < 0.001). CONCLUSIONS: Pretreatment BQ chewing habit worsens the prognosis of BMSCC in Taiwan. BQ chewing is a prognostic indicator that can be used in conjunction with clinical staging to help plan the treatment for the patients.

Adult↗

PubMed2005

Inhibition of cyclooxygenase activity, platelet aggregation and thromboxane B2 production by two environmental toxicants: m- and o-cresol.

Cresol is a well-known environmental pollutant, toluene metabolite, uremic toxicant and accidental poisoning product. Formocresol, a preparation of formalin and cresol, is also used as a root canal medicament and for pulpotomy of primary teeth. However, little is known about its effect on cardiovascular system. In this study, m-cresol inhibited the AA-induced platelet aggregation by 43-97% at concentrations ranging from 0.25 to 1 mM. Collagen-induced platelet aggregation was also inhibited by 0.25-1 mM of m-cresol by 47-98%. Accordingly, o-cresol (0.1-0.5 mM) also inhibited the AA-induced platelet aggregation by 46-96% and the collagen-induced platelet aggregation by 35-88% at concentrations of 0.1-1 mM. AA- and collagen-induced platelet thromboxane B(2) (TXB(2)) production was inhibited by even 0.1 mM of m-cresol with 88 and 54% of inhibition, respectively. The o-cresol (0.1 mM) also inhibited the AA- and collagen-induced platelet TXB(2) production with 91 and 97% respectively. Although m- and o-cresol (<1 mM) showed little effect on thrombin-induced platelet aggregation, they effectively inhibited the thrombin-induced platelet TXB(2) production. The m-cresol (2 and 5 mM) inhibited the COX-1 activity by 55-99%, but showed little effect on COX-2 enzyme activity. Moreover, o-cresol (0.5 and 1 mM) inhibited the COX-1 activity by 40-95%. COX-2 enzyme activity was inhibited by 68% at a concentration of 5 mM o-cresol. These results indicate that acute cresol-poisoning, direct root canal medication with formocresol or long-term occupational exposure to cresol and toluene may potentially suppress blood clot formation and lead to tissue hemorrhage via inhibition of platelet aggregation, TXB(2) production and COX enzyme activity.

Animals↗

PubMed2005

Tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces cell proliferation in normal human bronchial epithelial cells through NFkappaB activation and cyclin D1 up-regulation.

Cigarette smoke contains several carcinogens known to initiate and promote tumorigenesis as well as metastasis. Nicotine is one of the major components of the cigarette smoke and the 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a tobacco-specific carcinogen. Here, we demonstrated that NNK stimulated cell proliferation in normal human bronchial epithelial cells (NHBE) and small airway epithelial cells (SAEC). Cells exposed to NNK resulted in an increase in the level of cyclin D1 protein (as early as 3-6 h). Increased phosphorylation of the Rb Ser(795) was detected at 6-15 h after NNK treatment and thereby promoted cells entering into the S phase (at 15-21 h). The increased cyclin D1 protein level was induced through activation of the transcription factor, nuclear factor kB (NFkappaB), in the NHBE cells. Treatment of the NHBE cells with PD98059, an ERK1/2 (extracellular signal-regulated protein kinase)-specific inhibitor, specifically suppressed the NNK-induced IkappaBalpha phosphorylation at position 32 of the serine residue, suggesting that the ERK1/2 kinase was involved in the IkappaBalpha phosphorylation induced by NFkappaB activation. To determine whether the NNK-induced NFkappaB activation and cyclin D1 induction were also observed in vivo, A/J mice were treated with NNK (9.1 mg) for 20 weeks and the results showed a significant induction of cyclin D1 and NFkappaB translocation determined by immunoblotting analyses. We further demonstrated that the nicotine acetylcholine receptor (nAchR), which contains the alpha3-subunit, was the major target mediating NNK-induced cyclin D1 expression in the NHBE cells. In summary, our findings demonstrate for the first time that NNK could stimulate normal human bronchial cell proliferation through activation of the NFkappaB, which in turn up-regulated the cyclin D1 expression.

Bronchi↗

PubMed2005

Long-term effect of pulsed Nd:YAG laser irradiation on cultured human periodontal fibroblasts.

BACKGROUND AND OBJECTIVES: The purpose of this study was to investigate the long-term effect of Nd:YAG laser irradiation on cultured human periodontal fibroblasts (hPF). STUDY DESIGN/MATERIALS AND METHODS: The cultured hPF were irradiated by pulsed Nd:YAG laser. The power delivery was 50 mJ x 10 pps (pulse per second) with irradiation duration 60, 120, 180, or 240 seconds. The viability and collagen content of laser-irradiated hPF were assessed on day 5 after laser treatment. Light microscope and transmission electron microscope (TEM) were used to observe cytomorphological change. The irradiated hPF cultured in mineralizing medium for 28 days were examined by alizarin red S and Von Kossa stain. RESULTS: The cellular viability and collagen content of hPF decreased after Nd:YAG laser irradiation. Cell damage was noted with retraction of cellular processes, loss of normal architecture, and lysis of some cells. However, survived hPF proliferated and migrated to the cell-debris-associated deposits. The electron-dense cytoplasm and amorphous organelles in laser-damaged cells was revealed by TEM. In vitro mineralization was demonstrated in the long-term laser-irradiated hPF cultured in mineralizing medium. CONCLUSION: Nd:YAG laser irradiation induced partial loss of cellular viability and collagen content. The co-existence of viable cells and progressive degeneration of laser-damaged cells was associated with the in vitro mineralization of hPF.

Calcification, Physiologic↗

PubMed2005

Stimulation of glutathione depletion, ROS production and cell cycle arrest of dental pulp cells and gingival epithelial cells by HEMA.

2-Hydroxy-ethyl methacrylate (HEMA) is the major component released from resin-modified glass ionomer cements and dental adhesives. Human tissues mainly affected by HEMA are oral epithelium and dental pulp. We treated human gingival epithelial S-G cells and pulp fibroblasts (HPF) with various concentrations of HEMA, to evaluate its effects on cell growth, cell cycle progression, intracellular glutathione (GSH) level and reactive oxygen species (ROS) production. HEMA-induced growth inhibition in HPF and S-G cells in a dose-dependent manner, which may be partially explained by induction of cell cycle perturbation. G(2)/M phase arrest was noted after exposure of HPF to 5 and 10mm of HEMA, concomitant with glutathione depletion and ROS production. S-phase arrest occurred in S-G cells when treated with 2.5 and 5mm, while at 10mm a sub-G(0)/G(1) peak was noted, indicating the potential induction of apoptosis. GSH depletion was marked in S-G cells only at concentrations of 5 and 10mm, but excessive ROS production was noted at concentration of 1mm and rose with dose increase between 1 and 5mm, then lessened at 10mm. This suggested that the increase of ROS in S-G cells was not mainly caused by GSH depletion. These results helped to define the mechanism of the cytotoxicity caused by HEMA.

Apoptosis↗

PubMed2005

Higher expressions of p53 and proliferating cell nuclear antigen (PCNA) in atrophic oral lichen planus and patients with areca quid chewing.

OBJECTIVE: The aim of the study was to examine the expressions of p53 and proliferating cell nuclear antigen (PCNA) in oral lichen planus (OLP) in relation to its clinical behavior and the patients' oral habits. STUDY DESIGN: Immunohistochemical study was carried out to investigate the expressions of p53 and PCNA in 56 OLP specimens. The results were correlated with the clinical behavior of the disease and the patients' oral habits. The expression rates were further compared with those of normal oral mucosa (NOM), epithelial hyperkeratosis (EH), epithelial dysplasia (ED), and squamous cell carcinoma (SCC). RESULTS: The staining rate of p53 (28.6%) and PCNA labeling index (LI) (27.6 +/- 8.8%) in OLP were similar to those in EH ( P = .868, .074, respectively), but higher than those of NOM and lower than those of ED and SCC (all P < .05). In OLP, no significant correlations were found between p53 or PCNA expression and the patients' age, gender, lesion duration, location, size, number of site, presence of pain, presence of local irritant, and the habits of alcohol drinking and cigarette smoking (all P > .05). In addition, the mean PCNA LI of p53+ cases was close to that of p53- cases (P = .38). However, the staining rate of p53 in OLP was higher in areca quid (AQ) chewers compared to abstainers (P = .001), and the mean PCNA LI in atrophic cases was higher than that in hypertrophic cases (P = .029). Interestingly, the staining rate of p53 and mean PCNA LI were significantly increased in AQ chewers with atrophic OLP (100%, 36.7% +/- 9.0%, respectively), which were similar to those in ED and SCC (all P > .05). CONCLUSIONS: Although this study could not confirm the precancerous nature of OLP by the relatively low p53 and PCNA expression, the results do suggest that atrophic form OLP and patients with AQ chewing habit may have a higher disease activity in view of higher expression rates of p53 and PCNA in the lesions.

Adolescent↗

PubMed2004

Effects of root-end filling materials and eugenol on mitochondrial dehydrogenase activity and cytotoxicity to human periodontal ligament fibroblasts.

Various root-end filling materials have been used to prevent the entry of root-canal pathogens into periapical regions. Five root-end filling materials were compared regarding the cytotoxicity, apoptosis, and mitochondrial dehydrogenase (MDH) activities of human periodontal ligament (PDL) fibroblasts, with the use of a novel transwell culture system. Exposure to IRM (a ZnO eugenol-based intermediate restorative material), a 2-ethoxybenzoic acid cement (Super EBA), and amalgam for 3 days inhibited the MDH activity of PDL fibroblasts as indicated by decrease in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction by 97%, 95%, and 51%, respectively. Evident suppression of MTT reduction by amalgam and glass ionomer cement (GIC) was noted after 5 days of exposure, with 73% and 46% of inhibition, respectively. Mineral trioxide aggregates (MTA) showed little effect on MDH activity. IRM and Super EBA were cytotoxic to PDL fibroblasts as indicated by a trypan blue dye exclusion technique. GIC and amalgam showed mild cytotoxicity. IRM, GIC, and amalgam further induced apoptosis of PDL cells, as revealed by the presence of sub-G0/G1 DNA content in flow cytometric histogram. Twenty-four-hour exposure to IRM and Super EBA elevated the MDH activities to 156% and 117%, correspondingly, of that of control. Eugenol, a phenolic ingredient in Super EBA and IRM, also increases MDH activity of PDL fibroblasts by 45% and 51%, at concentrations of 0.5 and 1 mM. However, at concentrations higher than 0.5 mM, eugenol decreased the number of viable PDL fibroblasts. These results suggest that MTA is a biocompatible root-end filling material, followed by self-curing Fuji II GIC and amalgam. IRM and Super EBA ingredients induced marked cytotoxicity and transiently stimulate MDH activities, which is possibly due to their content of eugenol and induction of cellular adaptive response.

Alkaline Phosphatase↗

PubMed2004

The induction of prostaglandin E2 production, interleukin-6 production, cell cycle arrest, and cytotoxicity in primary oral keratinocytes and KB cancer cells by areca nut ingredients is differentially regulated by MEK/ERK activation.

There are about 200-600 million betel quid (BQ) chewers in the world. BQ chewing is one of the major risk factor of hepatocarcinoma, oropharyngeal, and esophagus cancers in Taiwan, India, and Southeast Asian countries. Thus, the precise molecular mechanisms deserve investigation. We used cultured primary keratinocytes and KB cells, RT-PCR, flow cytometry, Western blotting, and ELISA to evaluate whether alterations in early gene expression is crucial in the carcinogenic processes of BQ. We observed the induction of c-Fos mRNA expression in human gingival keratinocyte (GK) and KB carcinoma cells by areca nut (AN) extract and arecoline. A maximal increment in c-fos gene expression was shown at about 30 min after challenge. AN extract (100-800 microg/ml) and arecoline (0.1-0.8 mM) also stimulated ERK1/ERK2 phosphorylation with a maximal stimulation at 5-10 min of exposure. Pretreatment by U0126 (30 microM), a MEK inhibitor, markedly inhibited the c-Fos, cyclooxygenase-2 (COX-2), and IL-6 mRNA expression of the KB epithelial cells. In addition, U0126 and PD98059 (50 microM) also decreased AN extract- and arecoline-associated PGE2 and IL-6 production in GK and KB cells. However, U0126 by itself arrested the cells in G0/G1 phase, but was not able to prevent AN- and arecoline-induced cell death or apoptosis. In contrast, U0126 enhanced the AN-induced apoptosis of KB cells. AN ingredients thus play a significant role in the pathogenesis of oropharyngeal cancer by activation of MEK1/ERK/c-Fos pathway, which promotes keratinocyte inflammation, cell survival, and affects cell cycle progression.

Apoptosis↗

PubMed2004

Protease-activated receptor-1-induced calcium signaling in gingival fibroblasts is mediated by sarcoplasmic reticulum calcium release and extracellular calcium influx.

Thrombin is a serine protease activated during injury and inflammation. Thrombin and other proteases generated by periodontal pathogens affect the behavior of periodontal cells via activation of protease-activated receptors (PARs). We noted that thrombin and PAR-1 agonist peptide stimulated intracellular calcium levels ([Ca2+]i) of gingival fibroblasts (GF). This increase of [Ca2+]i was inhibited by EGTA and verapamil. U73122 and neomycin inhibited thrombin- and PAR-1-induced [Ca2+]i. Furthermore, 2-APB (75-100 microM, inositol triphosphate [IP3] receptor antagonist), thapsigargin (1 microM), SKF-96365 (200 microM) and W7 (50 and 100 microM) also suppressed the PAR-1- and thrombin-induced [Ca2+]i. However, H7 (100, 200 microM) and ryanodine showed little effects. Blocking Ca2+ efflux from mitochondria by CGP37157 (50, 100 microM) inhibited both thrombin- and PAR-1-induced [Ca2+]i. Thrombin induced the IP3 production of GF within 30-seconds of exposure, which was inhibited by U73122. These results indicate that mitochondrial calcium efflux and calcium-calmodulin pathways are related to thrombin and PAR-1 induced [Ca2+]i in GF. Thrombin-induced [Ca2+]i of GF is mainly due to PAR-1 activation, extracellular calcium influx via L-type calcium channel, PLC activation, then IP3 binding to IP3 receptor in sarcoplasmic reticulum, which leads to intracellular calcium release and subsequently alters cell membrane capacitative calcium entry.

Boron Compounds↗

PubMed2004

Hamsters chewing betel quid or areca nut directly show a decrease in body weight and survival rates with concomitant epithelial hyperplasia of cheek pouch.

Betel quid (BQ) chewing is strongly associated with the occurrence of oral leukoplakia, oral submucous fibrosis, and oral cancer. There are about 200-600 million BQ chewers in the world. Previous animal studies support the potential carcinogenicity of BQ in different test systems. However, little animal experiment has let hamsters or rats to chew BQ directly, similar to that in humans. In the present study, we established a hamster model of chewing BQ or areca nut (AN). A total of 81 2-week-old hamsters were randomly divided into three groups: 25 for control group, 28 for BQ-chewing group, and 28 for AN-chewing group. These animals were fed with powdered diet with/without BQ or AN for 18 months. Although the consumption of BQ or AN showed some variations, hamsters fed with powdered diet could chew and grind AN or BQ into small pieces of coarse fibers during the entire experimental period. The survival rate of AN-chewing hamsters decreased significantly after 6 months of exposure. The mean survival time was 15.6 +/- 0.9 months for control animals, 13.6 +/- 0.98 months for AN-chewing animals, and 15.7 +/- 0.55 months for BQ-chewing animals. The body weight of BQ- or AN-chewing animals also decreased after 4-13 months. Hamsters fed with AN for 18 months showed hyperkeratosis in 80% and acanthosis in 50% of cheek pouches. Animals fed with BQ for 18 months also showed hyperkeratosis in 93% and acanthosis in 14% of cheek pouches. These results indicate that AN and BQ components may induce alterations in proliferation and differentiation of oral epithelial cells. Animal model of chewing BQ or AN can be useful for future tumor initiation, promotion and chemoprevention experiments simulating the condition of BQ chewing in humans.

Animals↗