RESUMEN
OBJECTIVE: Transforming growth factor ß1 (TGF-ß1) plays a role in repair and dentinogenesis in dental pulp. The purpose of this study was to study how TGF-ß1 affects 2 differentiation markers, Runt-related transcription factor 2 (Runx-2) and ALP, in dental pulp cells. STUDY DESIGN: Primary-cultured human dental pulp cells were treated with TGF-ß1 with or without pretreatment and coincubation with 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene (U0126, a mitogen-induced extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor), Noggin (a bone morphogenetic protein inhibitor), or 4-(5-benzol[1,3]dioxol-5-yl-4-pyrldin-2-yl-1H-imidazol-2-yl)-benzamide hydrate (SB431542, an activin receptor-like kinase (ALK) 5/Smad2/3 inhibitor). The differentiation status of pulp cells was evaluated by ALP staining and quantitative ALP activity assay. Changes in ALP and Runx-2 mRNA expression were determined by reverse-transcription polymerase chain reaction. RESULTS: Cells under the treatment of TGF-ß1 (5 and 10 ng/mL) showed a decrease in ALP activity and gene expression of ALP and Runx-2. Pretreatment by U0126 and Noggin was not effective to prevent the TGF-ß1-induced decline of ALP activity. Interestingly, SB431542 prevented the TGF-ß1-induced decline of ALP activity and ALP and Runx-2 gene expression. CONCLUSION: TGF-ß1 down-regulates Runx-2 and ALP in human dental pulp cells via ALK5/Smad2/3 signaling. These events may play important roles at specific stages of pulpal repair and dentinogenesis.
Asunto(s)
Fosfatasa Alcalina/metabolismo , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Pulpa Dental/metabolismo , Regulación hacia Abajo/fisiología , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Transducción de Señal/fisiología , Proteína Smad2/metabolismo , Proteína smad3/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Fosfatasa Alcalina/antagonistas & inhibidores , Benzamidas/farmacología , Proteínas Morfogenéticas Óseas/antagonistas & inhibidores , Butadienos/farmacología , Proteínas Portadoras/farmacología , Células Cultivadas , Subunidad alfa 1 del Factor de Unión al Sitio Principal/antagonistas & inhibidores , Pulpa Dental/citología , Pulpa Dental/enzimología , Dioxoles/farmacología , Inhibidores Enzimáticos/farmacología , Humanos , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Nitrilos/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Proteína Smad2/antagonistas & inhibidores , Proteína smad3/antagonistas & inhibidores , Factor de Crecimiento Transformador beta1/farmacologíaRESUMEN
Epidemiological studies have shown a strong association between environmental exposure to betel quid (BQ) and oral cancer. Areca nut (AN), an ingredient of BQ, contains genotoxic and mutagenic compounds. In this study, we found that AN extract (ANE) inhibited the growth of Chinese hamster ovary cells (CHO-K1) in a dose- and time-dependent manner. Intracellular reactive oxygen species (ROS) levels and micronuclei (MN) frequency were significantly increased following ANE treatment in CHO-K1 cells. Addition of catalase markedly inhibited ANE-induced MN formation, indicating that ANE-induced genotoxicity was correlated with intracellular H(2)O(2). Incubation of CHO-K1 cells with ANE (400-800 microg/ml) for 24 hr caused G2/M arrest, and prolonged exposure to ANE (800 microg/ml) significantly induced cell death. Surprisingly, ANE itself caused cytokinesis failure and subsequent increase in binucleated cell formation. Coexposure to catalase (2,000 U/ml) and ANE (800 microg/ml) reduced the generation of binucleated cells, indicating that ANE-induced cytokinesis failure was associated with oxidative stress. Following prolonged exposure to ANE, an accumulation of hyperploid/aneuploid cells concomitant with bi-, micro- or multinucleated cells was found. In summary, our results demonstrate that ANE exposure to CHO-K1 cells caused increased MN frequency, G2/M arrest, cytokinesis failure, and an accumulation of hyperploid/aneuploid cells. These events are associated with an increase in intracellular H(2)O(2) level and actin filament disorganization.
Asunto(s)
Actinas/metabolismo , Areca/química , Citocinesis/efectos de los fármacos , Micronúcleos con Defecto Cromosómico/inducido químicamente , Extractos Vegetales/toxicidad , Especies Reactivas de Oxígeno/metabolismo , Animales , Células CHO , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Cricetinae , Cricetulus , Peróxido de Hidrógeno/metabolismo , Extractos Vegetales/químicaRESUMEN
Transforming growth factor beta (TGF-beta) may regulate the biological activities of dental pulp cells. We found that human dental pulp cells expressed TGF-beta1, TGF-beta2, and a little amount of TGF-beta3 messenger RNA (mRNA). The exposure of pulp cells to TGF-beta2 induced the phosphorylation of Smad2/3, Smad1/5/8, and extracellular regulated-kinase 1/2 (ERK1/2) as observed by Western blotting. Exposure to TGF-beta2 decreased the alkaline phosphatase (ALP) mRNA expression and enzyme activity. Pretreatment of pulp cells with SB431542 (an inhibitor of TGF-beta ALK-4, ALK-5, and ALK-7 receptors) but not U0126 (a MEK1 inhibitor) prevented the inhibition of viable cell number, ALP activity, and mRNA expression by TGF-beta2 in dental pulp cells. These results suggest that TGF-beta may affect the growth and differentiation of dental pulp cells via an autocrine fashion by activation of the ALK/Smad2/3-signal transduction pathways. TGF-beta2 possibly regulates the differentiation of pulp cell at specific stages synergistically with other factors.
Asunto(s)
Pulpa Dental/metabolismo , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Proteínas Smad Reguladas por Receptores/metabolismo , Factor de Crecimiento Transformador beta2/fisiología , Fosfatasa Alcalina/metabolismo , Benzamidas/farmacología , Diferenciación Celular , Proliferación Celular , Pulpa Dental/citología , Dioxoles/farmacología , Inhibidores Enzimáticos/farmacología , Quinasas MAP Reguladas por Señal Extracelular/fisiología , Humanos , Quinasas Quinasa Quinasa PAM/fisiología , Isoformas de Proteínas , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/antagonistas & inhibidores , Factor de Crecimiento Transformador beta1/biosíntesis , Factor de Crecimiento Transformador beta2/biosíntesisRESUMEN
The cementodentinal tear is rarely detected by noninvasive procedures owing to its clinical picture simulating a root fracture or a periodontal or endodontic lesion. We present a case of complex cementodentinal tears in a 79-year-old woman who presented a repeated swelling at the labial mucosa of the left maxillary central incisor for 6 months. Periapical radiographs demonstrated a vertical radiolucent fracture line extending from the root apex along the mesial aspect of the root to near the middle portion of the root of the left maxillary central incisor. Because endodontic re-treatment failed to cure the disease, periapical surgery was performed, and 2 fractured U-shaped root fragments around the apical root surface were removed. Histologic examination showed that the 2 fractured root fragments were composed mainly of the dentin covered by a thin layer of the cementum and overlying periodontal ligament tissue, suggesting cementodentinal tears. A swelling recurred 8 months after the initial operation. Therefore, a second periapical surgery was performed. Although no obvious fracture line was observed around the root surface, the second surgery did not cure the disease, either. A persistent small swelling was noted at the alveolar mucosa of the affected tooth during the follow-up. We conclude that although a cementodentinal tear can be detected by a careful radiographic examination, its clinical outcome is not predictable by surgical removal only.
Asunto(s)
Incisivo/patología , Periodontitis Periapical/etiología , Ápice del Diente/lesiones , Fracturas de los Dientes/complicaciones , Anciano , Apicectomía , Cemento Dental/lesiones , Fístula Dental/etiología , Fístula Dental/cirugía , Dentina/lesiones , Femenino , Humanos , Maxilar , Periodontitis Periapical/cirugía , Fracturas de los Dientes/cirugíaRESUMEN
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.
Asunto(s)
Butiratos/farmacología , Ciclo Celular/efectos de los fármacos , Depuradores de Radicales Libres/farmacología , Especies Reactivas de Oxígeno/metabolismo , Neoplasias de la Lengua , Apoptosis/efectos de los fármacos , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Expresión Génica/efectos de los fármacos , Humanos , Oxidación-Reducción , Neoplasias de la Lengua/metabolismo , Neoplasias de la Lengua/patologíaRESUMEN
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.