RESUMO
OBJECTIVE: To assess the potential protective effects of three polyphenols oleuropein, rutin and curcumin, on joint ageing and osteoarthritis (OA) development. DESIGN: Sixty 4-week-old Dunkin-Hartley guinea pigs were randomized into four groups and received daily during 31 weeks either standard guinea pig diet (control group) or a standard guinea pig diet enriched with oleuropein (0.025%), rutin (0.5%) or rutin/curcumin (0.5%/0.25%) association. Biomarkers of OA (Coll2-1, Coll2-1NO2, Fib3-1, Fib3-2, ARGS), as well as inflammation prostaglandin E2 (PGE2) were quantified in the serum. Histological assessments of knee cartilage and synovial membrane were performed at week 4 (five young reference guinea pigs) and week 35. RESULTS: At week 35, guinea pigs in the control group spontaneously developed significant cartilage lesions with mild synovial inflammation. The histological scores of cartilage lesions and synovitis were well correlated with the increased level of serum biomarkers. Histologically, all treatments significantly reduced the cartilage degradation score (P < 0.01), but only oleuropein significantly decreased the synovial histological score (P < 0.05) and serum PGE2 levels (P < 0.01) compared to the control group. Coll2-1 was decreased by rutin and the combination of rutin/curcumin, Fib3-1 and Fib3-2 were only decreased by the rutin/curcumin mixture, while Coll2-1NO2 was significantly decreased by all treatments (P < 0.05). CONCLUSION: Oleuropein and rutin ± curcumin significantly slowed down the progression of spontaneous OA lesions in guinea pigs. While no additive effect was seen in the curcumin + rutin group, the differential effects of oleuropein and rutin on inflammatory and cartilage catabolic markers suggest an interesting combination for future studies in OA protection.
Assuntos
Curcumina/uso terapêutico , Iridoides/uso terapêutico , Osteoartrite/prevenção & controle , Rutina/uso terapêutico , Animais , Biomarcadores/sangue , Cobaias , Glucosídeos Iridoides , Masculino , Osteoartrite/sangueRESUMO
OBJECTIVE: Develop and evaluate the feasibility and validity of the Nutrition and Functionality Assessment (NFA) which identifies "target" older adults who could benefit from a personalized program following evaluation of their nutrition status and physical functionality. DESIGN: Cross-sectional study. SETTING: Community and geriatric day-care centers and university in Japan. PARTICIPANTS: 267 older adults aged 65-90. MEASUREMENTS: The "target" individuals were screened based on gait speed (0.6-1.5 m/s). Nutrition (Mini Nutrition Assessment-short form and protein intake), strength (30s chair sit-to-stand and hand-grip strength) and endurance (6-minute walk) were assessed. Physical activity was monitored using a tri-axil accelerometer for a week. Fried frailty phenotype was also assessed. RESULTS: Out of 267 individuals, 185 (69%) had gait speed between 0.6-1.5 m/s, corresponding to our "target" group from which, 184 (95%) completed the nutrition and physical functionality assessments with the physical activity monitoring. The NFA was completed in approximately 30 minutes. No adverse events directly due to the NFA were reported. NFA physical functionality and global scores were significantly related to frailty phenotype but nutrition score was not related to frailty phenotype. CONCLUSION: The study demonstrated that the NFA is a safe and feasible tool to screen target older adults and simultaneously evaluate their nutritional status and physical functionality. Validity of the NFA was partially confirmed by the significant association of the global and physical functionality scores with frailty phenotype. More studies are required to validate and maximize the applicability of the NFA in communities and institutions in Japan and elsewhere.
Assuntos
Avaliação Geriátrica , Avaliação Nutricional , Desempenho Físico Funcional , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Humanos , JapãoRESUMO
PURPOSE: To develop a metabolically competent, human immortalized corneal epithelial cell line for use in toxicity and inflammation studies. METHODS: Primary corneal epithelial cells (P-CEPI) were immortalized by a recombinant simian virus (SV)40 T antigen retroviral vector defective for viral replication. The cells were grown in serum-free medium with the addition of bovine pituitary extract, cloned at passage 15 and one of the best-growing clones, CEPI-17-CL4, was extensively characterized for differentiation and metabolic characteristics of the human corneal epithelium. Methods used were immunostaining, reverse transcription-polymerase chain reaction (RT-PCR), northern blot analysis, and enzyme assays. RESULTS: The CEPI-17-CL4 cells showed a typical cobblestone morphology, grew to more than 200 passages and expressed the SV40 T antigen in the nucleus of every cell. Immunofluorescence staining for CEPI-17-CL4 cells was strongly positive for keratins (K)8, K18, and K19 and vimentin; weakly positive for K3, K13, and K17; and negative for K4, K7, and K14. Expression of cytokines (interleukin [IL]-1alpha, IL-1beta, IL-6, IL-8, tumor necrosis factor-alpha, and IL-ra), growth factors (transforming growth factor [TGF]-alpha, epidermal growth factors [EGF], EGF receptor [EGFR], TGF-beta1, TGF-beta2, and platelet-derived growth factor-beta) and cytochrome P450 enzymes (1A1, 2C, 2E1, and 3A5) was similar in CEPI-17-CL4 cells and human corneal epithelial samples obtained in biopsy. The CEPI-17-CL4 cells were metabolically competent for enzymes glutathione S-transferase, quinone reductase, aflatoxin aldehyde reductase, glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase. CONCLUSIONS: The CEPI-17-CL4 cells are truly immortal and express an extensive array of cytokines, growth factors, and metabolic enzymes that resemble the original tissue. These characteristics, which remain stable up to high passage, will allow reproducible, mechanistic studies on toxicity, inflammation, and wound healing.
Assuntos
Linhagem Celular Transformada , Epitélio Corneano/citologia , Epitélio Corneano/metabolismo , Citocinas/metabolismo , Epitélio Corneano/enzimologia , Epitélio Corneano/fisiologia , Olho/efeitos dos fármacos , Substâncias de Crescimento/metabolismo , Humanos , Ceratite/patologia , Ceratite/fisiopatologia , Fenótipo , Testes de ToxicidadeRESUMO
PURPOSE: To investigate the epithelial nature of primary and SV40 virus-immortalized human corneal epithelial (CEPI) cells and to study a variety of functional responses to some key inflammatory agents (bradykinin [BK], histamine, and platelet-activating factor [PAF]) and their antagonists in these cells. METHODS: Primary CEPI (P-CEPI) and clone 4 of the SV40 virus-immortalized (CEPI-17-CL4) cells were analyzed for their interaction with several monoclonal antibodies selective for various cytokeratins to define their immunocytochemical characteristics and phenotypic traits. Both cell types were tested for their ability to respond to BK, histamine, and PAF and their antagonists, using the production of [3H]inositol phosphates ([3H]IPs) as an index of receptor activation. The ability of BK, PAF, and histamine to stimulate cytokine release and the induction of mRNA for matrix metalloproteinase-1 (MMP-1) were also studied using enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction techniques, respectively. RESULTS: P-CEPI and CEPI-17-CL4 cells were both shown to possess the epithelial cell cytokeratins labeled with AE1 and AE3 antibodies. The potencies (EC50s) of BK, histamine, and PAF were similar for stimulating [3H]IPs production in P-CEPI and CEPI-17-CL4 cells: BK = 2.27 to 2.99 nM, PAF = 17.1 to 18.26 nM, and histamine = 1.65 to 5.74 microM (all n = 3 to 6). Both cell types also responded similarly to receptor-selective antagonists for BK, PAF, and histamine (Hoe-140: Ki = 10.1 to 11.9 nM; PCA-4248: Ki = 315 to 421 nM; triprolidine: Ki = 0.8 to 4.76 nM; all n = 5 to 10). Histamine (100 microM) and interleukin-1alpha (IL-1alpha, 10 ng/ml) significantly stimulated IL-6 and granulocyte macrophage colony-stimulating factor release, and histamine, BK, and PAF stimulated the mRNA for MMP-1 in these cells. CONCLUSIONS: These studies have shown that the primary and immortalized human corneal epithelial cells express functional BK (a B2 subtype), histamine (an H1 subtype), and PAF receptors and exhibit very similar immunocytochemical, signal transduction, and pharmacological properties. Therefore, the CEPI-17-CL4 cells (currently at passage 220) appear to provide a useful representative in vitro model system to study the physiological and pathologic aspects of the human corneal epithelium.
Assuntos
Bradicinina/farmacologia , Epitélio Corneano/fisiologia , Antagonistas dos Receptores Histamínicos/farmacologia , Histamina/farmacologia , Fator de Ativação de Plaquetas/farmacologia , Receptores de Superfície Celular , Receptores Acoplados a Proteínas G , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bradicinina/antagonistas & inibidores , Linhagem Celular Transformada/citologia , Linhagem Celular Transformada/efeitos dos fármacos , Linhagem Celular Transformada/metabolismo , Células Cultivadas , Criança , Pré-Escolar , Colagenases/biossíntese , Citocinas/metabolismo , Primers do DNA/química , Ensaio de Imunoadsorção Enzimática , Epitélio Corneano/citologia , Epitélio Corneano/efeitos dos fármacos , Humanos , Fosfatos de Inositol/metabolismo , Queratinas/metabolismo , Metaloproteinase 1 da Matriz , Pessoa de Meia-Idade , Fator de Ativação de Plaquetas/antagonistas & inibidores , Glicoproteínas da Membrana de Plaquetas/metabolismo , RNA Mensageiro/metabolismo , Receptores da Bradicinina/metabolismo , Receptores Histamínicos H1/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Natural polyphenols found in rosemary have not only potent antioxidant activities but also anticarcinogenic properties. We have studied some of the molecular mechanisms involved in their chemopreventive action using in vitro human liver and bronchial cell models. Rosemary extract, or its active components, carnosol or carnosic acid are potent inhibitors of DNA adduct formation induced by benzo(a)pyrene or aflatoxin B1. At least two mechanisms are involved in the anticarcinogenic action of rosemary extract: (i) inhibition of the metabolic activation of procarcinogens catalysed by the phase I cytochrome P450 enzymes; (ii) induction of the detoxification pathway catalysed by the phase II enzymes such as glutathione S-transferase.
Assuntos
Brônquios/enzimologia , Citocromo P-450 CYP1A2/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Fígado/enzimologia , Oxigenases de Função Mista/metabolismo , Especiarias , Aflatoxina B1/farmacologia , Western Blotting , Brônquios/efeitos dos fármacos , Células Cultivadas , Citocromo P-450 CYP3A , Adutos de DNA/biossíntese , Adutos de DNA/efeitos dos fármacos , Glutationa Transferase/metabolismo , Humanos , Fígado/efeitos dos fármacos , Mutagênicos/farmacologia , Extratos Vegetais/farmacologiaRESUMO
OBJECTIVE: To evaluate the plasma kinetics in man of epicatechin from black chocolate. DESIGN: An intervention study with 8 volunteers. Each served as his own control. Theobromine was used as control marker of the chocolate intake. SETTING: Metabolic Unit, Nestle Research Center, Vers-chez-les-Blanc, Switzerland. SUBJECTS: Eight healthy male volunteers (4 smokers and 4 non-smokers) were enrolled in this study. They abstained from foods rich in polyphenols (coffee, tea, wine, fruit juice, cocoa products) for 24 h prior to the test until its completion. INTERVENTION: Volunteers ate 40 g and 80 g of black chocolate (Nestle Noir) together with bread with a one-week interval. Blood samples were drawn every hour during the first 4h and a last one at 8 h after chocolate consumption. Plasma samples were analysed for epicatechin and theobromine content by HPLC. RESULTS: Plasma concentrations of epicatechin and theobromine increased markedly after chocolate consumption (P = 0.002 and P= 0.001, respectively), reaching a maximum between 2 and 3 h. The maximal concentration and area under the curve of plasma kinetics of both substrates correlated very well with the dose of chocolate. CONCLUSIONS: Epicatechin is absorbed from chocolate and is rapidly eliminated from plasma. Attainable plasma values are 0.7 micromol/l from 80g of black chocolate.
Assuntos
Cacau/metabolismo , Catequina/farmacocinética , Adulto , Área Sob a Curva , Catequina/sangue , Cromatografia Líquida de Alta Pressão , Meia-Vida , Humanos , Masculino , Teobromina/sangue , Teobromina/farmacocinéticaRESUMO
The coffee-specific diterpenes cafestol and kahweol (C + K) have been reported to be anticarcinogenic in several animal models. Proposed mechanisms involve a co-ordinated modulation of several enzymes responsible for carcinogen detoxification, thus preventing reactive agents interacting with critical target sites. To address the human relevance of the chemoprotective effects of C + K against aflatoxin B(1) (AFB1) genotoxicity observed in rat liver, and to compare the mechanisms of protection involved in both species, animal and human hepatic in vitro test systems were applied. In rat primary hepatocytes, C + K reduced the expression of cytochrome P450 CYP 2C11 and CYP 3A2, the key enzymes responsible for AFB1 activation to the genotoxic metabolite aflatoxin B1-8,9 epoxide (AFBO). In addition, these diterpenes induced significantly GST Yc2, the most efficient rat GST subunit involved in AFBO detoxification. These effects of C + K resulted in a marked dose-dependent inhibition of AFB1-DNA binding in this rat in vitro culture system. Their relevance in humans was addressed using liver epithelial cell lines (THLE) stably transfected to express AFB1 metabolising cytochrome P450s. In these cells, C + K also produced a significant inhibition of AFB1-DNA adducts formation linked with an induction of the human glutathione S-transferase GST-mu. Altogether, these results suggest that C + K may have chemoprotective activity against AFB1 genotoxicity in both rats and humans.
Assuntos
Aflatoxina B1/toxicidade , Café/química , Sistema Enzimático do Citocromo P-450/metabolismo , Diterpenos/farmacologia , Fígado/efeitos dos fármacos , Animais , Western Blotting , Células Cultivadas , Quimioprevenção , Sistema Enzimático do Citocromo P-450/genética , Adutos de DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Humanos , Fígado/citologia , Fígado/enzimologia , Ratos , Ratos Sprague-DawleyRESUMO
Human and mouse liver microsomes and membranes isolated from Escherichia coli, which expressed cytochrome P450 (CYP) 1A2, 3A4, 2C9 or 2D6, were used to investigate CYP-mediated metabolism of five selected dietary flavonoids. In human and mouse liver microsomes kaempferol, apigenin and naringenin were hydroxylated at the 3'-position to yield their corresponding analogs quercetin, luteolin and eriodictyol, whereas hesperetin and tamarixetin were demethylated at the 4'-position to yield eriodictyol and quercetin, respectively. Microsomal flavonoid metabolism was potently inhibited by the CYP1A2 inhibitors, fluvoxamine and -naphthoflavone. Recombinant CYP1A2 was capable of metabolizing all five investigated flavonoids. CYP3A4 recombinant protein did not catalyze hesperetin demethylation, but showed similar metabolic profiles for the remaining compounds, as did human microsomes and recombinant CYP1A2, although the reaction rates in general were lower as compared to CYP1A2. CYP2C9 catalyzed the 4'-demethylation of tamarixetin, whereas CYP2D6 did not seem to play any role in the metabolism of the selected flavonoids. The major involvement in flavonoid metabolism of human CYP1A2, which mediates the formation of metabolites with different biochemical properties as compared to the parent compound and furthermore is known to be expressed very differently among individuals, raises the important question of whether individual differences in the CYP enzyme activity might affect the beneficial outcome of dietary flavonoids, rendering some individuals more or less refractory to the health-promoting potential of dietary flavonoids.
Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Flavonoides/metabolismo , Animais , Biotransformação , Inibidores das Enzimas do Citocromo P-450 , Dieta , Inibidores Enzimáticos/farmacologia , Feminino , Análise de Alimentos , Humanos , Técnicas In Vitro , Cinética , Membranas/enzimologia , Camundongos , Camundongos Endogâmicos C57BL , Microssomos Hepáticos/enzimologia , Proteínas Recombinantes/metabolismo , Especificidade da EspécieRESUMO
Comparisons were made between the Intelligent Prosthesis (IP), Mauch and pneumatic swing phase control damping systems on the same prosthesis worn by a high level trans-femoral amputee. Speeds self selected by corridor walking (4.4-5.5 kmh-1) proved not to be sustainable for treadmill walking. Comfortable speeds were attained when the subject walked on a treadmill at 2.0, 2.6 and 3.2 kmh-1 in two tests for each prosthesis type. Oxygen uptake (VO2), cadence and heart rate were measured over 5 minute walks interspersed with rest periods. Spearman's correlation was used to test for differences between prosthesis types at each speed. At the two slower speeds no significant difference was found, but at the higher speed of 3.2 kmh-1, the IP was associated with a significantly lower VO2 (p < 0.05). A two way analysis of variance with replication (ANOVA) demonstrated a significant difference between VO2 for different limb types (p = 0.015). A square law function was fitted to the mean VO2 for each prosthesis type by the method of least squares regression. ANOVA demonstrated a significant difference between velocity coefficients for the different prosthesis types (p < 0.05). Cadence was almost constant during the period of each walk, varying by 1 step min-1 at most. However the test-retest differences in cadence were considerable. It is concluded that there was little difference in energy expenditure between prosthesis types at slower speeds, but at higher speeds (==> 3.2km h-1) the IP gave a lower oxygen uptake by about 10%.
Assuntos
Amputados/reabilitação , Membros Artificiais/normas , Metabolismo Energético , Terapia Assistida por Computador/normas , Caminhada/fisiologia , Adulto , Análise de Variância , Teste de Esforço , Humanos , Perna (Membro) , Masculino , Microcomputadores , Consumo de OxigênioRESUMO
In this study we investigated the effect of supplementing the diet of the growing male rat with different levels of calcium (from low to higher than recommended intakes at constant Ca/P ratio), on multiple factors (bone mass, strength, size, geometry, material properties, turnover) influencing bone strength during the bone accrual period. Rats, age 28days were supplemented for 4weeks with high Ca (1.2%), adequate Ca (0.5%) or low Ca level (0.2%). Bone metabolism and structural parameters were measured. No changes in body weight or food intake were observed among the groups. As anticipated, compared to the adequate Ca intake, low-Ca intake had a detrimental impact on bone growth (33.63 vs. 33.68mm), bone strength (-19.7% for failure load), bone architecture (-58% for BV/TV) and peak bone mass accrual (-29% for BMD) due to the hormonal disruption implied in Ca metabolism. In contrast, novel, surprising results were observed in that higher than adequate Ca intake resulted in improved peak bone strength (106 vs. 184N/mm for the stiffness and 61 vs. 89N for the failure load) and bone material properties (467 vs. 514mPa for tissue hardness) but these effects were not accompanied by changes in bone mass, size, microarchitecture or bone turnover. Hormonal factors, IGF-I and bone modeling were also evaluated. Compared to the adequate level of Ca, IGF-I level was significantly lower in the low-Ca intake group and significantly higher in the high-Ca intake group. No detrimental effects of high Ca were observed on bone modeling (assessed by histomorphometry and bone markers), at least in this short-term intervention. In conclusion, the decrease in failure load in the low calcium group can be explained by the change in bone geometry and bone mass parameters. Thus, improvements in mechanical properties can be explained by the improved quality of intrinsic bone tissue as shown by nanoindentation. These results suggest that supplemental Ca may be beneficial for the attainment of peak bone strength and that multiple factors linked to bone mass and strength should be taken into account when setting dietary levels of adequate mineral intake to support optimal peak bone mass acquisition.
Assuntos
Osso e Ossos/fisiologia , Cálcio da Dieta/farmacologia , Crescimento e Desenvolvimento/efeitos dos fármacos , Absorciometria de Fóton , Animais , Fenômenos Biomecânicos/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea/efeitos dos fármacos , Osso e Ossos/anatomia & histologia , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/efeitos dos fármacos , Calcificação Fisiológica/efeitos dos fármacos , Cálcio/metabolismo , Fêmur/anatomia & histologia , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Fêmur/fisiologia , Imageamento Tridimensional , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ratos Sprague-Dawley , Tíbia/anatomia & histologia , Tíbia/diagnóstico por imagem , Tíbia/efeitos dos fármacos , Tíbia/fisiologia , Suporte de Carga , Microtomografia por Raio-XAssuntos
Envelhecimento , Síndromes de Imunodeficiência , Estado Nutricional , Osteoporose , Sarcopenia , Idoso , Animais , Osso e Ossos/patologia , Humanos , Sistema Imunitário/patologia , Síndromes de Imunodeficiência/dietoterapia , Músculo Esquelético/patologia , Osteoporose/dietoterapia , Sarcopenia/dietoterapiaRESUMO
Papillomaviruses are tissue specific and replicate in differentiating keratinocytes. We are interested in the question of tissue specificity at the level of transcription. We used extracts from human keratinocytes and human fibroblasts at low passage number and from HeLa cells to look for factors binding to the E6 promoter of human papillomavirus type 18 (HPV-18) DNA by footprint and gel mobility shift experiments. We found a factor present in HeLa and keratinocyte extracts but not in fibroblast extracts which bound about 160 base pairs upstream from the start of E6. The binding site included the sequence TGACTAAG, which resembles the consensus binding site for the AP-1 family of proteins. Synthetic oligonucleotides containing this binding site specifically competed with factor binding to HPV-18 DNA, as did the AP-1 sequence of simian virus 40. They also inhibited transcription from the E6 promoter in vitro in extracts from HeLa cells. Thus, the presence of this keratinocyte-specific factor seems to be important for HPV-18 transcription.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Queratinócitos/metabolismo , Papillomaviridae/genética , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo , Transcrição Gênica , Replicação Viral , Sequência de Bases , Ligação Competitiva , Núcleo Celular/metabolismo , Fibroblastos/metabolismo , Células HeLa/metabolismo , Humanos , Dados de Sequência Molecular , Sondas de Oligonucleotídeos , Papillomaviridae/fisiologia , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-jun , Vírus 40 dos Símios/genéticaRESUMO
Human papillomaviruses (HPV) replicate in keratinocyte but not fibroblast cells. Several factors, including AP1 (Jun/Fos), contribute to the cell-type specific transcription of HPV genes. The binding of AP1 upstream of the HPV type 18 early gene E6 is essential for transcription of the early genes. Here we show that AP1 levels are low in early passage human fibroblast extracts. In contrast, human keratinocyte extracts contain high levels of AP1. In agreement with this, in vivo an AP1-dependent promoter is more active in keratinocytes than in fibroblasts. Pulse chase experiments indicated that Jun and Fos are relatively stable in human keratinocyte cells after serum induction, whereas in early passage human fibroblasts they are rapidly broken down. Nuclear extracts of these fibroblasts contain a cysteine proteinase which can degrade AP1. Furthermore, the activity of a cathepsin B-like cysteine proteinase is elevated in these human fibroblast extracts relative to other cell types. Interestingly, after several passages in culture the fibroblasts lose this proteinase activity and the amount of AP1 increases. Taken together, these results suggest that the quantitative difference in AP1 proteins between human keratinocytes and fibroblasts is due to a difference in protein stability. The cathepsin B-like cysteine proteinase is a candidate for a role in the unusually rapid breakdown of AP1 in early passage human fibroblast cells. Low levels of AP1 in the fibroblasts correlate with the low activity of AP1-dependent promoters, like that of HPV-18, in these cells.
Assuntos
Proteínas de Ligação a DNA , Fibroblastos/metabolismo , Queratinócitos/metabolismo , Proteínas Oncogênicas Virais/genética , Papillomaviridae/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Adulto , Animais , Sequência de Bases , Células Cultivadas , Cisteína Endopeptidases/metabolismo , Elementos Facilitadores Genéticos , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Gravidez , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , RNA Mensageiro/metabolismoRESUMO
Papillomaviruses are believed to play an important role in the development of genital carcinoma. Herpes simplex virus (HSV) has been proposed as a cofactor. Here we show that HSV-1 interferes with the expression of human papillomavirus (HPV-18) genes in HeLa cells by reducing the amount of papillomaviral mRNA. By 7 h after HSV-1 infection, expression was reduced by a factor of 50. Experiments with the HSV-1 mutant tsK, with cycloheximide and with u.v.-irradiated virus indicated that the reduction was not due to newly made immediate early, early or late HSV-1 gene products but rather to a component of the virion. Replication of the HSV-1 is therefore not required for the reduction of the HPV-18 mRNA. The HSV-1 strain 17+, which has only a very weak virion host shutoff function, still specifically decreased the level of the papillomaviral mRNA suggesting that either the decrease is due to a new HSV-1 function or that the HPV-18 mRNA is especially sensitive to the low residual host shutoff activity of strain 17+. Experiments with the virus 17(41-), in which the host shutoff function is inactivated by a mutation in the UL41 gene, showed clearly that it is the host shutoff function which is responsible. The papillomaviral mRNA therefore appears to be hypersensitive to the herpesvirus host shutoff function.
Assuntos
Genes Virais/genética , Papillomaviridae/genética , Simplexvirus/genética , Interferência Viral/genética , Regulação Viral da Expressão Gênica , Gliceraldeído-3-Fosfato Desidrogenases/genética , Células HeLa , Humanos , Papillomaviridae/crescimento & desenvolvimento , RNA Mensageiro/análise , RNA Viral/análise , Simplexvirus/crescimento & desenvolvimento , Proteínas Virais/genética , Vírion/genética , Vírion/crescimento & desenvolvimentoRESUMO
Infection of estrogen-responsive cells (MCF-7) with herpes simplex virus type 1 or 2 stimulates expression of the estrogen receptor message. Experiments on infection with the mutant virus, tsK, together with transfection studies implicate the virion protein, Vmw65, in the response. Cellular protein synthesis is essential for estrogen receptor mRNA expression.
Assuntos
Herpes Simples/genética , Receptores de Estrogênio/genética , Northern Blotting , Neoplasias da Mama/genética , Cicloeximida/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , RNA Mensageiro/genética , Simplexvirus , Células Tumorais Cultivadas , Proteínas Virais/fisiologiaRESUMO
Viral mRNAs from lesions containing human papillomavirus type 6 (HPV-6) have previously been mapped on the viral DNA but relatively little is known about the control of mRNA production, or whether the mapped RNA termini correspond to promoters. By analysis of run-off transcripts synthesized in vitro, primer extension and measurements of promoter activity in fragments of the viral DNA introduced into cells, we have identified three promoters in the early region of the HPV-6b genome. These are: (i) at the end of the long control region upstream of the E6 open reading frame; (ii) upstream of E7 and (iii) upstream of E1. The promoter upstream of E1 was the most active. These results contrast with results of similar assays with HPV-18, in which the strongest promoter was that controlling expression of the transforming genes E6 and E7. In addition, a novel promoter was detected close to E5a, upstream of the late genes.
Assuntos
Genoma Viral , Papillomaviridae/genética , Regiões Promotoras Genéticas , Sequência de Bases , DNA Viral , Células HeLa , Humanos , Dados de Sequência Molecular , Proteínas Oncogênicas Virais/genética , Papillomaviridae/químicaRESUMO
The commonly used spice and flavouring agent, rosemary, derived from the leaves of the plant Rosmarinus officinalis L., displays antioxidant properties in foods and in biological systems. Moreover, in animal models rosemary components were found to inhibit the initiation and tumour promotion phases of carcinogenesis. In this work, we studied the mechanisms by which rosemary components block initiation of carcinogenesis by the procarcinogen benzo[a]pyrene (B[a]P) in human bronchial epithelial cells (BEAS-2B). Whole rosemary extract (6 micrograms/ml) or an equivalent concentration of its most potent antioxidant constituents, carnosol or carnosic acid, inhibited DNA adduct formation by 80% after 6 h co-incubation with 1.5 muM B[a]P. Under similar conditions, cytochrome P450 (CYP) 1A1 mRNA expression was 50% lower in the presence of rosemary components, and CYP1A1 activity was inhibited 70-90%. The observed reduction of DNA adduct formation by rosemary components may mostly result from the inhibition of the activation of benzo[a]pyrene to its ultimate metabolites. Carnosol also affected expression of the phase II enzyme glutathione-S-transferase which is known to detoxify the proximate carcinogenic metabolite of B[a]P. Treatment of BEAS-2B cells with carnosol (1 microgram/ml) for 24 h resulted in a 3- to 4-fold induction of GST pi mRNA. Moreover, expression of a second important phase II enzyme, NAD(P)H: quinone reductase, was induced by carnosol in parallel with GST pi. Therefore, rosemary components have the potential to decrease activation and increase detoxification of an important human carcinogen, identifying them as promising candidates for chemopreventive programs.
Assuntos
Anticarcinógenos/uso terapêutico , Benzo(a)pireno/antagonistas & inibidores , Benzo(a)pireno/toxicidade , Brônquios/efeitos dos fármacos , Carcinógenos/toxicidade , Adutos de DNA/biossíntese , Mutagênicos/toxicidade , Extratos Vegetais/uso terapêutico , Brônquios/enzimologia , Brônquios/metabolismo , Neoplasias Brônquicas/induzido quimicamente , Neoplasias Brônquicas/prevenção & controle , Células Cultivadas , Inibidores das Enzimas do Citocromo P-450 , Sistema Enzimático do Citocromo P-450/genética , Adutos de DNA/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Indução Enzimática , Inibidores Enzimáticos/uso terapêutico , Glutationa Transferase/biossíntese , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Magnoliopsida/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Many natural dietary phytochemicals found compounds found in fruits, vegetables, spices and tea have been shown in recent years to be protective against cancer in various animal models. In the light of the potential impact of these compounds on human health it is important to elucidate the mechanisms involved. We therefore developed and characterized relevant in vitro models using immortalized human epithelial cell lines derived from target tissues in carcinogenesis, such as lung, liver and colon. Assays were established, allowing the evaluation of the cytotoxic and genotoxic effects of various procarcinogens, including nitrosamines, mycotoxins and heterocyclic amines on these metabolically-competent human epithelial cell lines. These cellular models appeared to be a useful tool to study the capacity of certain food components to block the initiation stage of carcinogenesis. The ability of carnosol and carnosic acid from rosemary as well as the synthetic dithiolethione, oltipraz, to block the formation of DNA adducts, and their effects on the expression of phase I and phase II enzymes was investigated. We have observed that both rosemary extracts and oltipraz inhibited benzo(a)pyrene- or aflatoxin B1-induced DNA adduct formation by strongly inhibiting CYP450 activities and inducing the expression of glutathione S-transferase. These results in human cell models give some insight into the different mechanisms involved in the chemopreventive action of both natural and synthetic compounds in relation to phase I and phase II enzymes.