RESUMEN
BACKGROUND: Crassocephalum crepidioides, a plant distributed in Okinawa Islands, is known in folk medicine; however, its anticancer activity has not been investigated. The aim of this study was to determine the in vitro and in vivo antitumor activities of C. crepidioides on murine Sarcoma 180 (S-180) and related molecular mechanisms. METHODS: The antitumor effect of C. crepidioides was evaluated in S-180-cell-bearing mice. Cell growth was assessed using a colorimetric assay. Nitrite and nitrate levels were measured by colorimetry. The expression levels of inducible NO synthase (iNOS) in murine RAW264.7 macrophages was assessed by reverse transcriptase-polymerase chain reaction. Activation of iNOS promoter was detected by reporter gene. Activation of nuclear factor-κB (NF-κB) was evaluated by electrophoretic mobility shift assay. The role of NF-κB signaling was analyzed using inhibitors of NF-κB and dominant-negative mutants, and Western blot analysis. RESULTS: C. crepidioides extract delayed tumor growth in S-180-bearing mice. However, it did not inhibit S-180 cell growth in vitro. Supernatant of cultured C. crepidioides-stimulated RAW264.7 macrophages was cytotoxic to S-180 cells. This cytotoxicity was associated with nitric oxide (NO) production. NF-κB signaling pathway was crucial for the transcriptional activation of iNOS gene. Isochlorogenic acid, a component of C. crepidioides, induced NF-κB activation and iNOS expression. CONCLUSIONS: The results highlight the oncolytic and immunopotentiation properties of C. crepidioides mediated through NF-κB-induced release of NO from macrophages.
Asunto(s)
Asteraceae/química , Ácido Clorogénico/análogos & derivados , Macrófagos/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo II/metabolismo , Óxido Nítrico/biosíntesis , Fitoterapia , Sarcoma/tratamiento farmacológico , Animales , Antineoplásicos Fitogénicos/farmacología , Antineoplásicos Fitogénicos/uso terapéutico , Línea Celular , Línea Celular Tumoral , Ácido Clorogénico/farmacología , Ácido Clorogénico/uso terapéutico , Femenino , Macrófagos/metabolismo , Ratones , Ratones Endogámicos BALB C , FN-kappa B/metabolismo , Óxido Nítrico Sintasa de Tipo II/genética , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Plantas Medicinales , Sarcoma/metabolismo , Transducción de Señal/efectos de los fármacos , Activación Transcripcional/efectos de los fármacosRESUMEN
AIM: To evaluate the effects of fucoidan, a complex sulfated polysaccharide extract from marine seaweed, on hepatitis C virus (HCV) RNA load both in vitro and in vivo. METHODS: HCV-1b replicon-expressing cells were cultured in the presence of fucoidan obtained from Cladosiphon okamuranus Tokida cultivated in Okinawa, Japan, and quantified the level of HCV replication. In an open-label uncontrolled study, 15 patients with chronic hepatitis C, and HCV-related cirrhosis and hepatocellular carcinoma were treated with fucoidan (0.83 g/d) for 12 mo. The clinical symptoms, biochemical tests, and HCV RNA levels were assessed before, during, and after treatment. RESULTS: Fucoidan dose-dependently inhibited the expression of HCV replicon. At 8-10 mo of treatment with fucoidan, HCV RNA levels were significantly lower relative to the baseline. The same treatment also tended to lower serum alanine aminotransferase levels, and the latter correlated with HCV RNA levels. However, the improved laboratory tests did not translate into significant clinical improvement. Fucoidan had no serious adverse effects. CONCLUSION: Our findings suggest that fucoidan is safe and useful in the treatment of patients with HCV-related chronic liver diseases. Further controlled clinical trials are needed to confirm the present findings.
Asunto(s)
Antivirales/uso terapéutico , Hepacivirus/efectos de los fármacos , Hepatitis C Crónica/tratamiento farmacológico , Polisacáridos/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Alanina Transaminasa/sangre , Antivirales/efectos adversos , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/virología , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Femenino , Hepacivirus/genética , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/diagnóstico , Humanos , Japón , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/virología , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/virología , Masculino , Persona de Mediana Edad , Proyectos Piloto , Polisacáridos/efectos adversos , ARN Viral/sangre , Factores de Tiempo , Resultado del Tratamiento , Carga ViralRESUMEN
Fucoidan, a sulfated polysaccharide, has significant cytotoxic activity against tumor cells; however, the mechanism(s) of this action remains poorly understood. The present study was designed to determine the in vitro and in vivo effects of fucoidan and their molecular mechanisms. Fucoidan from Cladosiphon okamuranus Tokida cultivated in Okinawa, Japan, delayed tumor growth in Sarcoma 180 (S-180)-bearing mice. However, it failed to inhibit S-180 cell growth in vitro. Activated macrophages are known to have anti-tumor effects. Murine RAW264.7 macrophages stimulated with fucoidan exerted cytotoxicity towards S-180 cells in vitro. This cytotoxicity was associated with nitric oxide (NO) production. Both cytocidal effect and NO production were significantly inhibited by L-NAME, an inhibitor of NO synthase (NOS). Furthermore, activation of nuclear factor-κB was a key step in the transcriptional activation of the inducible NOS gene. Taken together, our results indicate that the anti-tumor activity of fucoidan on S-180 cells is mediated through increased NO production by fucoidan-stimulated macrophages via nuclear factor-κB-dependent signaling pathway.
Asunto(s)
Antineoplásicos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Óxido Nítrico/metabolismo , Polisacáridos/farmacología , Animales , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , FN-kappa B/metabolismo , Óxido Nítrico Sintasa de Tipo II/biosíntesis , Óxido Nítrico Sintasa de Tipo II/genética , Regiones Promotoras Genéticas , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Distribución Aleatoria , Sarcoma 180/tratamiento farmacológico , Sarcoma 180/metabolismo , Sarcoma 180/patología , Transducción de Señal/efectos de los fármacosRESUMEN
BACKGROUND: Helicobacter pylori secretes vacuolating cytotoxin (VacA) that damages the gastric epithelium by erosion and loosening of tight junctions. VacA has also immunosuppressive effects, inhibiting interleukin (IL)-2 secretion by interference with the T cell receptor/IL-2 signaling pathway. This study investigated the effect of VacA on gene expression of T cells. MATERIALS AND METHODS: Gene expression profile of a T cell line, Jurkat, was analyzed by the cDNA microarray technique after VacA challenge. The expression of specific mRNAs was assessed by reverse transcription-polymerase chain reaction. Interleukin (IL)-8 concentrations in culture supernatants and cell surface expression of CD69 were measured by enzyme-linked immunosorbent assay and flow cytometry, respectively. We evaluated nuclear factor-kappaB (NF-kappaB) activation in Jurkat cells challenged with VacA by luciferase assay, electrophoretic mobility shift assay, and Western blot analysis. RESULTS: VacA produced two or greater fold up-regulation of expression of 60 genes. Most of these genes were associated with signal transduction, regulation of gene expression, apoptosis, and inflammation. Up-regulation of four genes (IL8, IL2RA, ICAM1, and CD69) was confirmed. The supernatants of cells incubated with VacA showed significantly higher secretion levels of IL-8 than those incubated without VacA. VacA also induced the cell surface expression of CD69. Since microarray analysis indicated NF-kappaB was involved in the transcriptional activation of the above genes, we examined NF-kappaB signaling pathway. VacA activated NF-kappaB via classical but not alternative pathway. CONCLUSIONS: VacA has two paradoxical effects on T cells, immunosuppression, and proinflammatory effects. The latter is mediated by NF-kappaB activation.
Asunto(s)
Proteínas Bacterianas/inmunología , Infecciones por Helicobacter/genética , Helicobacter pylori/inmunología , FN-kappa B/genética , Transducción de Señal , Linfocitos T/inmunología , Proteínas Bacterianas/genética , Línea Celular , Perfilación de la Expresión Génica , Infecciones por Helicobacter/inmunología , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/microbiología , Helicobacter pylori/genética , Humanos , FN-kappa B/inmunología , Linfocitos T/metabolismoRESUMEN
BACKGROUND: The inflammatory response in Helicobacter pylori-infected gastric tissue is mediated by cag pathogenicity island (PAI)-dependent activation of nuclear factor-kappaB (NF-kappaB). Phosphatidylinositol 3-kinase (PI3K)/Akt signaling is known to play a role in NF-kappaB activation, but little information is available on the relationship between H. pylori and PI3K/Akt signaling in gastric epithelial cells. We examined whether H. pylori activates Akt in gastric epithelial cells, the role of cag PAI in this process and the role of Akt in regulating H. pylori-induced NF-kappaB activation. RESULTS: Phosphorylated Akt was detected in epithelial cells of H. pylori-positive gastric tissues. Although Akt was activated in MKN45 and AGS cells by coculture with cag PAI-positive H. pylori strains, a cag PAI-negative mutant showed no activation of Akt. H. pylori also induced p65 phosphorylation. PI3K inhibitor suppressed H. pylori-induced p65 phosphorylation and NF-kappaB transactivation, as well as interleukin-8 expression. Furthermore, transfection with a dominant-negative Akt inhibited H. pylori-induced NF-kappaB transactivation. Transfection with small interference RNAs for p65 and Akt also inhibited H. pylori-induced interleukin-8 expression. CONCLUSION: The results suggest that cag PAI-positive H. pylori activates Akt in gastric epithelial cells and this may contribute to H. pylori-mediated NF-kappaB activation associated with mucosal inflammation and carcinogenesis.
Asunto(s)
Helicobacter pylori/metabolismo , FN-kappa B/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factor de Transcripción ReIA/metabolismo , Línea Celular , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiología , Regulación de la Expresión Génica , Islas Genómicas , Infecciones por Helicobacter/metabolismo , Helicobacter pylori/genética , Humanos , Interleucina-8/biosíntesis , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Interferencia de ARNRESUMEN
Interleukin-12 (IL-12) is a heterodimeric cytokine produced by antigen-presenting cells that promotes the development of T-helper lymphocyte 1 (Th1). Chronic gastritis induced by Helicobacter pylori is considered a Th1-mediated process. IL-12 levels in gastric biopsy samples of H. pylori-infected patients are higher than in those of uninfected individuals, but the cellular source of IL-12 remains elusive. IL-12 staining was detected in mucosal epithelial cells, lymphocytes, and macrophages in specimens of patients with H. pylori-positive gastritis. Therefore, we investigated IL-12 p40 mRNA induction by H. pylori in gastric epithelial cells and T cells. Although cag pathogenicity island (PAI)-positive H. pylori induced IL-12 p40 mRNA expression, an isogenic mutant of the cag PAI failed to induce it in both cell types. Supernatants from H. pylori cultures and H. pylori VacA induced IL-12 p40 mRNA expression in T cells but not in epithelial cells. The activation of the IL-12 p40 promoter by H. pylori was mediated through NF-kappaB. The transfection of IkappaB kinase and NF-kappaB-inducing kinase dominant-negative mutants inhibited H. pylori-induced IL-12 p40 activation. Inhibitors of NF-kappaB, phosphatidylinositol 3-kinase, p38 mitogen-activated protein kinase, and Hsp90 suppressed H. pylori- and VacA-induced IL-12 p40 mRNA expression. The results indicate that H. pylori induces IL-12 p40 expression by the activation of NF-kappaB, phosphatidylinositol 3-kinase, and p38 mitogen-activated protein kinase. Hsp90 is also a crucial regulator of H. pylori-induced IL-12 p40 expression. In addition to the cag PAI, VacA might be relevant in the induction of IL-12 expression and a Th1-polarized response only in T cells.
Asunto(s)
Gastritis/inmunología , Regulación de la Expresión Génica , Infecciones por Helicobacter/inmunología , Helicobacter pylori/patogenicidad , Subunidad p40 de la Interleucina-12/metabolismo , Animales , Biopsia , Línea Celular , Células Epiteliales/inmunología , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Mucosa Gástrica/citología , Mucosa Gástrica/inmunología , Mucosa Gástrica/microbiología , Mucosa Gástrica/patología , Gastritis/microbiología , Gastritis/patología , Islas Genómicas , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Helicobacter pylori/inmunología , Humanos , Subunidad p40 de la Interleucina-12/genética , Células Jurkat/citología , Células Jurkat/inmunología , Células Jurkat/microbiología , Macrófagos/citología , Macrófagos/inmunología , Macrófagos/microbiología , Ratones , FN-kappa B/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
BACKGROUND: Legionella pneumophila is a facultative intracellular bacterium, capable of replicating within the phagosomes of macrophages and monocytes, but little is known about its interaction with human lung epithelial cells. We investigated the effect of L. pneumophila on the expression of interleukin-8 (IL-8) in human A549 alveolar and NCI-H292 tracheal epithelial cell lines. RESULTS: Infection of L. pneumophila strain, but not heat-killed strain, resulted in upregulation of IL-8. IL-8 mRNA expression was induced immediately after the infection and its signal became gradually stronger until 24 h after infection. On the other hand, IL-8 expression in A549 cells infected with L. pneumophila lacking a functional type IV secretion system was transient. The IL-8 expression was slightly induced at 16 h and increased at 24 h after infection with flagellin-deficient Legionella. Activation of the IL-8 promoter by L. pneumophila infection occurred through the action of nuclear factor-kappaB (NF-kappaB). Transfection of dominant negative mutants of NF-kappaB-inducing kinase, IkappaB kinase and IkappaB inhibited L. pneumophila-mediated activation of IL-8 promoter. Treatment with hsp90 inhibitor suppressed L. pneumophila-induced IL-8 mRNA due to deactivation of NF-kappaB. CONCLUSION: Collectively, these results suggest that L. pneumophila induces activation of NF-kappaB through an intracellular signaling pathway that involves NF-kappaB-inducing kinase and IkappaB kinase, leading to IL-8 gene transcription, and that hsp90 acts as a crucial regulator in L. pneumophila-induced IL-8 expression, presumably contributing to immune response in L. pneumophila. The presence of flagellin and a type IV secretion system are critical for Legionella to induce IL-8 expression in lung epithelial cells.
Asunto(s)
Células Epiteliales/inmunología , Interleucina-8/genética , Interleucina-8/inmunología , Legionella pneumophila/inmunología , Pulmón/inmunología , Benzoquinonas/farmacología , Línea Celular Tumoral , Ensayo de Cambio de Movilidad Electroforética , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Regulación de la Expresión Génica , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Humanos , Lactamas Macrocíclicas/farmacología , Legionella pneumophila/crecimiento & desarrollo , Pulmón/metabolismo , Pulmón/microbiología , FN-kappa B/metabolismo , Fosforilación , Regiones Promotoras Genéticas , Proteínas Serina-Treonina Quinasas/metabolismo , Transcripción Genética , Transfección , Quinasa de Factor Nuclear kappa BRESUMEN
CCL20 attracts immature dendritic cells and memory T cells and plays a role on mucosal surfaces in inflammation. However, whether Helicobacter pylori infection induces CCL20 in human gastric epithelial cells remains to be determined. The aim of this study was to analyze the molecular mechanism of H. pylori-induced CCL20 expression. Expression of CCL20 mRNA was assessed by reverse transcription-PCR. Five normal and five H. pylori-infected gastric tissue samples were stained immunohistochemically for CCL20. A luciferase assay was used to monitor activation of the CCL20 gene promoter, and an electrophoretic mobility shift assay was used to explore the binding of transcription factors to this promoter. The CCL20 expression in epithelial cells of H. pylori-positive tissues was higher than that in H. pylori-negative tissues. H. pylori induced CCL20 expression in gastric epithelial cell lines, and the induction was dependent on an intact cag pathogenicity island. Activation of the CCL20 promoter by H. pylori occurred through the action of NF-kappaB. Transfection of IkappaB kinase and NF-kappaB-inducing kinase dominant negative mutants inhibited H. pylori-mediated activation of CCL20. Treatment with an inhibitor of Hsp90 suppressed H. pylori-induced CCL20 mRNA due to deactivation of NF-kappaB. Collectively, these results suggest that H. pylori activates NF-kappaB through an intracellular signaling pathway that involves IkappaB kinase and NF-kappaB-inducing kinase, leading to CCL20 gene transcription, and that Hsp90 is a crucial regulator of H. pylori-induced CCL20 expression, presumably contributing to the immune response in H. pylori.