RESUMEN
OBJECTIVES: Computed tomography perfusion (CTP) data are important for hyperacute stroke decision making. Available comparisons between outputs of different CTP software packages show variable outcomes. Evaluation for factors associated with agreement between the volume estimates is limited. We assessed for differences in core and penumbra volume estimates of three CTP software packages - AutoMIStar, RAPID, and Vitrea - and analyzed factors associated with agreement between the volume estimates. MATERIALS AND METHODS: Differences between software estimates of penumbra and core volumes were calculated for each patient with suspected acute ischemic stroke who underwent CTP. Exploratory hierarchical clustering and principal component analysis were performed to identify factors of decreased volume estimate agreement. Two-sample t-tests were performed, stratified by large vessel occlusion (LVO) location. RESULTS: 579 CTP studies were performed; 267 were normal, 139 artifacts, with 172 included in the final analysis. 79/172 had LVO of internal carotid artery (ICA, n = 20), M1 (n = 38) and proximal M2 (n = 21). LVO was the only factor associated with decreased software package agreement, and proximal LVO location was associated with general trend of increasing mean differences and standard deviations between software packages (range of mean differences [SD]: non-LVO, -17-6 [4-33] ml; M2, -40-13 [5-39] ml; M1, -43-26 [16-58] ml; ICA, -76-39 [22-97] ml). CONCLUSIONS: Core and penumbra volume estimates can be affected by LVO location significantly between CTP software packages.
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Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Isquemia Encefálica/diagnóstico por imagen , Perfusión , Imagen de Perfusión/métodos , Estudios Retrospectivos , Programas Informáticos , Accidente Cerebrovascular/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodosRESUMEN
OBJECTIVES: There is limited published literature on the genetic risks of chronic inflammatory related disease (eg, obesity and cardiovascular disease) among the Central Asia population. The aim is to determine potential genetic loci as risk factors for obesity for the Kazakhstani population. SETTING: Kazakhstan. PARTICIPANTS: One hundred and sixty-three Kazakhstani nationals (ethnic groups: both Russians and Kazakhs) were recruited for the cross-sectional study. Linear regression models, adjusted for confounding factors, were used to examine the genetic associations of single nucleotide polymorphisms (SNPs) in 19 genetic loci with obesity (73 obese/overweight individuals and 90 controls). RESULTS: Overall, logistic regression analyses revealed genotypes C/T in CRP (rs1205), A/C in AGTR1 (rs5186), A/G in CBS (rs234706), G/G in FUT2 (rs602662), A/G in PAI-1 (rs1799889), G/T (rs1801131) and A/G (rs1801133) in MTHFR genes significantly decrease risk of overweight/obesity. After stratification for ethnicity, rs234706 was significantly associated with overweight/obesity in both Russians and Kazakhs, while rs1800871 was significant in Kazakhs only. CONCLUSIONS: This study revealed that variations in SNPs known to be associated with cardiovascular health can also contribute to the risks of developing obesity in the population of Kazakhstan.
RESUMEN
Oxidative stress is considered an important factor that promotes cell death in response to a variety of pathophysiological conditions. This study investigated the antioxidant properties of allicin, the principle ingredient of garlic, on preventing oxidative stress-induced injury. The antioxidant capacities of allicin were measured by using 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay and hydrogen peroxide (H(2)O(2))-induced cell damage on H9c2 cardiomyoblasts. Allicin (0.3-10 µM) pre-incubation could concentration-dependently attenuate the intracellular reactive oxygen species (ROS) increase induced by H(2)O(2) on H9c2 cells. It could also protect H9c2 cells against H(2)O(2)-induced cell damage. However, the DPPH free radical scavenging activity of allicin was shown to be low. Therefore, it is believed that the protective effect of allicin on H9c2 cells could inhibit intracellular ROS production instead of scavenging extracellular H(2)O(2) or free radicals. For the observed protective effect on H9c2 cells, allicin might also be effective in reducing free radical-induced myocardial cell death in ischemic condition.
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Depuradores de Radicales Libres/farmacología , Peróxido de Hidrógeno/toxicidad , Mioblastos Cardíacos/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Ácidos Sulfínicos/farmacología , Animales , Compuestos de Bifenilo , Línea Celular , Disulfuros , Oxidantes/toxicidad , Estrés Oxidativo , Picratos , RatasRESUMEN
Ethanol has been commonly used as a vehicle for drug discovery purpose in vitro. The human breast cancer MCF-7 estrogen dependent cell line is a common in vitro model used for hormonal therapy study. However, special precaution is suggested when ethanol is used in pharmacological tests as solvent in order to evaluate the biological activity of potential drugs especially concerning about the MCF-7. Ethanol was shown to stimulate the proliferation of this estrogen receptor positive cell line. Here, we have further demonstrated that the dose responsive stimulatory effect of ethanol on the MCF-7 cells after pre-incubating the breast carcinoma cells with phenol red-free medium and stripped fetal bovine serum. Our findings open a discussion for the evaluation of ethanol as solvent for drug discovery and screening when using MCF-7 cells as a testing model.
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Proliferación Celular/efectos de los fármacos , Portadores de Fármacos/farmacología , Etanol/farmacología , Células MCF-7/efectos de los fármacos , Humanos , Receptores de Estrógenos/metabolismo , Solventes/farmacologíaRESUMEN
CONTEXT: The poor prognostic outcome of breast cancer is largely due to its resistance to cancer therapies. Development of therapeutic agents that can inhibit growth and induce apoptosis in breast cancer cells can help solve the problem. Emodin is an active anthraquinone that has been reported to have diverse biological effects. OBJECTIVE: In this study, the anticancer effects of emodin on growth inhibition, apoptosis induction and the expression of apoptosis-related genes in MCF-7 cells were investigated. MATERIALS AND METHODS: Growth inhibition induced by emodin was investigated by the MTS assay and the colony formation assay; while emodin-induced apoptosis was determined by the COMET assay and DNA fragmentation detection. Emodin (35 µM)-induced alterations in the expression of apoptotic-related genes were detected by using real-time PCR. RESULTS: Emodin had significant growth inhibitory effects on MCF-7 cells with IC50 = 7.22 µg/ml (â¼30 µM). It also exerted a concentration-dependant inhibitory effect on the colony-forming ability of MCF-7 cells with IC50 = 7.60 µg/ml (â¼30 µM). Hallmarks of apoptosis, such as single-strand DNA breakage and DNA fragmentation, were observed in emodin-treated MCF-7 cells. The gene expression of Fas ligand (FASL) was up-regulated (p < 0.01) but those of MCL1, CCND1 and C-MYC were down-regulated (p < 0.05) in emodin-treated MCF-7 cells. DISCUSSION AND CONCLUSION: This study indicated that emodin could induce growth inhibition and apoptosis in MCF-7 cells through the modulation of the expression of apoptosis-related genes. The growth inhibitory effects of emodin might involve both the intrinsic and the extrinsic apoptotic pathways and cell cycle arrest.
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Antineoplásicos Fitogénicos/farmacología , Proteínas Reguladoras de la Apoptosis/metabolismo , Neoplasias de la Mama/tratamiento farmacológico , Carcinoma/tratamiento farmacológico , Emodina/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/genética , Catárticos/farmacología , Proliferación Celular/efectos de los fármacos , Ciclina D1/antagonistas & inhibidores , Ciclina D1/genética , Ciclina D1/metabolismo , Roturas del ADN de Cadena Simple/efectos de los fármacos , Fragmentación del ADN , Proteína Ligando Fas/biosíntesis , Proteína Ligando Fas/genética , Proteína Ligando Fas/metabolismo , Femenino , Humanos , Concentración 50 Inhibidora , Células MCF-7 , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/antagonistas & inhibidores , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Células Madre Neoplásicas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-myc/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismoRESUMEN
Hypercholesterolemia is a major risk factor for the development of cardiovascular disease and nonalcoholic fatty liver disease. Natural compounds have been proved to be useful in lowering serum cholesterol to slow down the progression of cardiovascular disease and nonalcoholic fatty liver disease. In the present study, the hypocholesterolemic and hepatoprotective effects of the dietary consumption of chlorogenic acid were investigated by monitoring plasma lipid profile (total cholesterol, triglycerides, high-density lipoprotein and low-density lipoprotein) in Sprague-Dawley rats fed with a normal diet, a high-cholesterol diet or a high-cholesterol diet supplemented with chlorogenic acid (1 or 10 mg/kg/day p.o.) for 28 days. Chlorogenic acid markedly altered the increased plasma total cholesterol and low-density lipoprotein but decreased high-density lipoprotein induced by a hypercholesterolemic diet with a dose-dependent improvement on both atherogenic index and cardiac risk factor. Lipid depositions in liver were attenuated significantly in hypercholesterolemic animals supplemented with chlorogenic acid. It is postulated that hypocholesterolemic effect is the primary beneficial effect given by chlorogenic acid, which leads to other secondary beneficial effects such as atheroscleroprotective, cardioprotective and hepatoprotective functions. The hypocholesterolemic functions of chlorogenic acid are probably due to the increase in fatty acids unitization in liver via the up-regulation of peroxisome proliferation-activated receptor α mRNA.
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Anticolesterolemiantes/farmacología , Ácido Clorogénico/farmacología , Hígado Graso/tratamiento farmacológico , Hipercolesterolemia/tratamiento farmacológico , PPAR alfa/metabolismo , Animales , Colesterol en la Dieta/efectos adversos , LDL-Colesterol/sangre , Dieta , Metabolismo de los Lípidos , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Enfermedad del Hígado Graso no Alcohólico , PPAR alfa/genética , Ratas , Ratas Sprague-Dawley , Regulación hacia ArribaRESUMEN
Cardiovascular disease (CVD) is a category of chronic noncommunicable diseases causing high global mortality and has been a heavy social burden in many countries. In the search of chemicals that arise from natural food source, allicin is one such ingredient from garlic that was discovered with the potential to provide beneficial effects to the cardiovascular system. From the pharmacokinetic studies, allicin is known to be hydrophobic and can be readily absorbed through the cell membrane without inducing any damage to the phospholipid bilayer and then rapidly metabolized to exert pharmacological effects that are important to the cardiovascular system. It was found to provide cardio-protective effects by inducing vasorelaxation and alleviating various pathological conditions of CVD, including cardiac hypertrophy, angiogenesis, platelet aggregation, hyperlipidemia and hyperglycemia. Allicin was also discovered to further protect the cardiovascular system by enhancing the antioxidant status by lowering the level of reactive oxygen species and stimulating the production of glutathione. Other pharmacological benefits such as anticancer and antimicrobial activities were also discussed. It is concluded that allicin can be potentially developed into a health product for the cardiovascular system.
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Antioxidantes/farmacología , Cardiotónicos/farmacología , Enfermedades Cardiovasculares/prevención & control , Ácidos Sulfínicos/farmacología , Inhibidores de la Angiogénesis/farmacología , Animales , Disulfuros , Depuradores de Radicales Libres/farmacología , Ajo/química , Humanos , Hiperglucemia/prevención & control , Hiperlipidemias/prevención & control , Inhibidores de Agregación Plaquetaria/farmacología , Ácidos Sulfínicos/farmacocinética , Vasodilatadores/farmacologíaRESUMEN
An extract of Curcuma longa was tested in hypercholesterolemic rats to investigate its potential therapeutic effect on vascular conditions. Four experimental groups were used: normal diet (ND) control group, high cholesterol diet (HCD) group, and HCD subgroups supplemented with turmeric extract at 100 or 300 mg/kg of body weight (HCD100Tur and HCD300Tur groups, respectively). Turmeric extract was fed orally to animals, and dietary treatments lasted for 28 days. Hypercholesterolemia developed in the HCD, HCD100Tur, and HCD300Tur rats. Segments of the thoracic aorta were isolated, and an organ bath experiment was used to assess the vasorelaxation capability among all rats. Rats fed only HCD showed a marked decrease in acetylcholine-induced vasorelaxation compared with ND control rats. The HCD100Tur and HCD300Tur rats showed significant improvement in vasorelaxation compared with HCD rats. When vasorelaxation was induced by high concentrations of sodium nitroprusside, no differences in vasorelaxation were observed among the four groups of rats. A mechanistic study showed that HCD100Tur and HCD300Tur rats had significantly higher levels of the antioxidant enzymes superoxide dismutase and glutathione peroxidase than HCD rats. The transcript levels of heat shock protein 70 (hsp70), bcl2, bax-α, caspase (casp3), and glyceraldehyde 3-phosphate dehydrogenase in aortic tissues indicated that hypercholesterolemia significantly increased the expression of bax-α and casp3 but down-regulated bcl2 expression compared with the control group. Turmeric increased the expression of hsp70 and bcl2 but greatly reduced casp3 expression, indicating that turmeric improves vasorelaxation of the aorta in hypercholesterolemic rats by increasing antioxidant enzyme activities and likely suppressing apoptosis.
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Aorta Torácica/efectos de los fármacos , Curcuma/química , Hipercolesterolemia/tratamiento farmacológico , Extractos Vegetales/administración & dosificación , Vasodilatación/efectos de los fármacos , Animales , Aorta Torácica/metabolismo , Aorta Torácica/fisiopatología , Caspasa 3/genética , Caspasa 3/metabolismo , Expresión Génica/efectos de los fármacos , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP70 de Choque Térmico/metabolismo , Humanos , Hipercolesterolemia/genética , Hipercolesterolemia/metabolismo , Hipercolesterolemia/fisiopatología , Técnicas In Vitro , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
The anticancer effects of traditional Chinese medicine (TCM) have attracted the attention of the public vis-à-vis existing cancer therapies with various side effects. Lycium barbarum fruit, commonly known as Gou Qi Zi in China, is a potential anticancer agent/adjuvant. Its major active ingredients, L. barbarum polysaccharides (LBP), scopoletin and 2-O-ß-D-glucopyranosyl-L-ascorbic acid (AA-2ßG), are found to have apoptotic and antiproliferative effects on cancer cell lines. Moreover, LBP also contributes to body's immunomodulatory effects and enhances effects of other cancer therapies. It is not known whether there are any undesirable effects. Further studies on its pharmacological mechanisms and toxicology could facilitate a safe usage of this TCM herb.
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Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Frutas/química , Factores Inmunológicos/farmacología , Factores Inmunológicos/uso terapéutico , Lycium/química , Preparaciones de Plantas/farmacología , Preparaciones de Plantas/uso terapéutico , Animales , Medicamentos Herbarios Chinos/farmacología , Medicamentos Herbarios Chinos/uso terapéutico , HumanosRESUMEN
CONTEXT: Grifola frondosa (Polyporaceae), maitake, is a widely consumed edible mushroom in some Asian countries. The fruit bodies and mycelia of maitake have shown different bioactive compounds with anticancer and other therapeutic properties. OBJECTIVE: This study evaluated three chemically modified maitake polysaccharide-peptides' (MPSP) adjuvant effect (in vivo) and anticancer activity (in vitro growth inhibitory effect) compared with crude MPSP from G. frondosa. MATERIALS AND METHODS: We investigated the possibility of enhancing the adjuvant effect and anticancer effect of crude MPSP by using simple chemical modification methods to convert crude MPSP to phosphorylated, acetylated or esterified MPSPs. The adjuvant effect and growth inhibitory effect were evaluated by C6 cell inoculated rat model with cyclophosphamide (CPA) treatment and in vitro cell viability assay, respectively. RESULTS: All four tested MPSPs showed significant adjuvant effect to CPA treatment on rats inoculated with C6 cancer cells. In addition, an obvious growth inhibitory effect was observed in C6 cancer cells but not in normal brain cells treated with various forms of MPSPs. Only phosphorylation could significantly (p < 0.05) improve the adjuvant effect (in vivo) and growth inhibitory effect. A same rank order (phosphorylated MPSP > esterified MPSP ≥ acetylated MPSP ≥ crude MPSP) of efficacy was observed in both the in vivo and in vitro assays. DISCUSSION AND CONCLUSION: This study showed chemical phosphorylation could markedly enhance both adjuvant effects and growth inhibitory effects. This study demonstrated the feasibility of enhancing the efficacy of MPSP by using a simple chemical modification method, and this provides a foundation for future study in this area.
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Antineoplásicos/farmacología , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Grifola , Proteoglicanos/farmacología , Acetilación , Animales , Antineoplásicos/síntesis química , Antineoplásicos/aislamiento & purificación , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Esterificación , Glioma/patología , Grifola/química , Masculino , Estructura Molecular , Fosforilación , Proteoglicanos/síntesis química , Proteoglicanos/aislamiento & purificación , Ratas , Ratas Sprague-Dawley , Relación Estructura-ActividadRESUMEN
UNLABELLED: The extract of Curcuma longa, better known as turmeric, was orally administered to experimental rats that were fed a high-cholesterol diet to investigate whether it could regulate plasma lipids and cholesterol levels and possibly improve hepatic conditions. With turmeric supplements, rats showed a significant decrease in total plasma cholesterol and low-density lipoprotein cholesterol but an increase in high-density lipoprotein cholesterol when compared with rats that were fed a high-cholesterol diet alone. Fatty liver developed in hypercholesterolemic rats with the high-cholesterol diet treatment, and this condition was markedly improved when rats were provided with turmeric supplements at 100 mg/kg or 300 mg/kg of body mass. The turmeric treatment resulted in a significant decrease in the total amount of hepatic lipid. Histological staining of liver tissues with Sudan III and hematoxylin showed that rats fed with a high-cholesterol diet alone had more and larger granular fat bodies than rats having turmeric extract supplementation in their high-cholesterol diet. Reverse-transcription polymerase chain reaction was used to assess the expression levels of enzymes involved in fat metabolism and cellular homeostasis in experimental rat livers. The results showed that rats fed a high-cholesterol diet supplemented with turmeric extract had a significant increase in the expression of cholesterol 7 α-hydroxylase, hemeoxygenase 1, and low-density lipoprotein receptors but a significant decrease in 3-hydroxy-3-methyl-glutaryl-CoA reductase level when compared with rats fed a normal or high-cholesterol diet, showing that turmeric prevents hypercholesterolemia and the formation of fatty liver by the modulation of expressions of enzymes that are important to cholesterol metabolism. PRACTICAL APPLICATION: Turmeric may be considered a functional food for regulating plasma cholesterol levels and preventing the development of fatty liver in people who frequently consume a high-cholesterol diet.
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Anticolesterolemiantes/uso terapéutico , Curcuma/química , Hígado Graso/tratamiento farmacológico , Regulación de la Expresión Génica/efectos de los fármacos , Hipercolesterolemia/prevención & control , Hígado/enzimología , Extractos Vegetales/uso terapéutico , Animales , Anticolesterolemiantes/administración & dosificación , Anticolesterolemiantes/farmacología , Colesterol 7-alfa-Hidroxilasa/genética , Colesterol 7-alfa-Hidroxilasa/metabolismo , Relación Dosis-Respuesta a Droga , Hígado Graso/sangre , Hígado Graso/metabolismo , Hígado Graso/patología , Hemo Oxigenasa (Desciclizante)/genética , Hemo Oxigenasa (Desciclizante)/metabolismo , Hidroximetilglutaril-CoA Reductasas/genética , Hidroximetilglutaril-CoA Reductasas/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Masculino , Extractos Vegetales/administración & dosificación , Extractos Vegetales/farmacología , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Receptores de LDL/genética , Receptores de LDL/metabolismo , Rizoma/químicaRESUMEN
Primary astrocyte cultures are the most commonly used in vitro model for neurobiological studies. We speculated that different protocols might induce differences not only in the percentage of astrocytes but also in their biological characteristics. In this study, we investigated the effects of four major protocols on the purity of astrocytes, cell viability, expression of glial fibrillary acidic protein (GFAP) and bystin of cultured astrocytes using MTT assay, immunocytochemical staining, and Western blot analysis. We demonstrated that the purity of astrocytes (98.9%) generated by the subculture (SC) procedure is significantly higher than those generated by primary culture (PC), shaken once culture (SK-1) or shaken twice culture (SK-2). We also showed that expressions of GFAP and bystin in astrocytes that are purified by the SK-2 or SK-1 procedures are significantly higher than those in astrocytes prepared by PC or SC. In addition, astrocytes cultured by SK-2 or SK-1 have a higher level of cell viabilities at most time points after ischemia compared with astrocytes cultured by PC or SC. These suggested that physical stimulation induced by "shaken" or culture operation might be able to activate astrocytes and implied that different procedures induce differences not only in the purity but also in the biological characteristics of astrocytes, such as the percentage of activated astrocytes, GFAP, and bystin expressions and responses to ischemia. A more detailed analysis about the effect of "culture protocol factor" on the biological characteristics of astrocytes is absolutely needed.
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Astrocitos/citología , Astrocitos/metabolismo , Moléculas de Adhesión Celular/biosíntesis , Técnicas de Cultivo de Célula/métodos , Proteína Ácida Fibrilar de la Glía/biosíntesis , Animales , Animales Recién Nacidos , Western Blotting , Supervivencia Celular , Células Cultivadas/citología , Células Cultivadas/metabolismo , Inmunohistoquímica , Ratones , Ratones Endogámicos ICRRESUMEN
BACKGROUND AND PURPOSE: The present study was designed to determine how ginsenoside Rg1, an active ingredient in ginseng root, exerts its oestrogenic effects. We hypothesize that Rg1 may exert oestrogen-like actions in MCF-7 cells by activating the mitogen-activated protein kinase (MAPK) pathway in a ligand-independent manner. EXPERIMENTAL APPROACH: MCF-7 cells were co-incubated with the MAPK inhibitor PD98059 to determine whether the stimulant effects of Rg1 on cell proliferation, the induction of IGF-IR and pS2, the functional transactivation of oestrogen receptor-alpha (ERalpha), as well as ERalpha phosphorylation are dependent on MAPK. The time-dependent responses of mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated protein kinase (ERK) to Rg1 in MCF-7 cells were studied. The responses of MEK phosphorylation to Rg1 in oestrogen receptor (ER)-negative HEK293 cells were also determined. The effects of Rg1 on cell proliferation and IGF-IR protein expression were studied in the presence of tyrosine kinase inhibitor genistein to elucidate the involvement of tyrosine kinase in mediating these effects. KEY RESULTS: The oestrogenic effects of Rg1 in MCF-7 cells were abolished in the presence of PD98059. Rg1 could induce MEK protein expression and the phosphorylation level of MEK and ERK significantly in a time- and dose-dependent manner. Rg1 activated MEK phosphorylation in ER-negative HEK293 cells in a time- and dose-dependent manner. Rg1 induction of cell proliferation and IGF-IR protein expression was abolished by co-treatment with genistein. CONCLUSIONS AND IMPLICATIONS: Taken together, these results show that the MAPK pathway is involved in mediating the oestrogen-like actions of Rg1 in MCF-7 cells and suggest that Rg1 may activate ERalpha via MEK/ERK in a ligand-independent manner.
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Estrógenos/farmacología , Ginsenósidos/farmacología , Sistema de Señalización de MAP Quinasas/fisiología , Neoplasias de la Mama , Línea Celular , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Activación Enzimática , Receptor alfa de Estrógeno/agonistas , Receptor alfa de Estrógeno/metabolismo , Femenino , Flavonoides/farmacología , Genisteína/farmacología , Humanos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Fosforilación , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Receptor IGF Tipo 1/biosíntesisRESUMEN
Ginsenoside Rg1, an active ingredient commonly found in ginseng root, was previously demonstrated to be a phytoestrogen that exerted estrogen-like activity without direct interaction with estrogen receptors (ERs) in human breast cancer (MCF-7) cells. The present study was designed to determine the molecular mechanism by which Rg1 exerted estrogenic effects. Co-incubation of MCF-7 cells with 1 microM of ER antagonist ICI182780 abolished the inductive effects of Rg1 on pS2 expression as well as ERE-luciferase activity, suggesting that the estrogenic effects of Rg1 were mediated through the endogenous ERs. To evaluate the relative involvement of ERalpha and ERbeta in mediating the actions of Rg1, ER-negative human embryonic kidney (HEK293) cells were co-transfected with the ERE-luciferase reporter construct and either ERalpha or ERbeta construct. The results showed that Rg1 could activate ERE-luciferase activity via the ERalpha-mediated pathway in a dose-dependent manner (10(-14) to 10(-6)M); whereas, the activation of ERbeta-mediated ERE-luciferase activity by Rg1 only occur at high concentration (10(-6)M). Furthermore, the results showed that 1pM Rg1 could rapidly induce phosphorylation of the AF-1 domain of ERalpha at serine 118 residue within the first 5 min of incubation, suggesting that Rg1 activates ERalpha in a ligand-independent manner. Taken together, our results indicate that Rg1 preferentially activates ERalpha via phosphorylation of AF-1 domain in the absence of receptor binding. This study is the first to provide evidence that ginsenoside Rg1 exerts estrogen-like actions via ligand-independent activation of ERalpha pathway.
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Receptor alfa de Estrógeno/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Ginsenósidos/farmacología , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Células Cultivadas , Evaluación Preclínica de Medicamentos , Estradiol/análogos & derivados , Estradiol/farmacología , Receptor alfa de Estrógeno/antagonistas & inhibidores , Fulvestrant , Genes Reporteros/efectos de los fármacos , Humanos , Factor I del Crecimiento Similar a la Insulina/farmacología , Ligandos , Luciferasas/genética , Fosforilación/efectos de los fármacos , Fitoestrógenos/farmacología , ARN Mensajero/metabolismo , Transducción de Señal/efectos de los fármacos , TransfecciónRESUMEN
The classical view of the molecular actions of estrogen is described by its interaction with the intracellular estrogen receptor (ER), the binding of hormone receptor complex to the estrogen response element (ERE) on the DNA and followed by the alterations of gene expressions. Recently it has been reported that membrane estrogen receptor (mER) exist and it is suggested to be G protein linked receptor. In this report we show that under steroid-free culture conditions supplemented with low percentage of charcoal-stripped serum, differential estrogen treatments of human breast cancer MCF7 cells induce different responses of cyclic AMP (cAMP) productions. Treating [2-(3)H]adenine-labeled MCF7 cells with 1 nM estrogen for 30 min stimulates cAMP production by measuring the ratio of [3H]cAMP:Total [3H]adenine nucleotides (ATP+ADP+cAMP), as determined by column chromatography, when compared with the control. This short-term estrogen treatment also significantly enhanced forskolin stimulated cAMP production when compared with the ratio of cAMP/Total measured in cells stimulated with forskolin alone. Pre-treating MCF7 cells with the same concentration of estrogen for 24h before the assay, on the contrary, significantly decreased the basal cAMP level and it also suppressed cAMP production stimulated with forskolin when compared with its respective value under short-term estrogen treatment. Estrogen receptor antagonist ICI 182780 abolished both the stimulatory and suppressive effect of estrogen on cAMP synthesis indicating both effects were mediated through ER. Pre-treating cells with pertussis toxin relieved the suppression of cAMP synthesis by chronic estrogen treatment. Our data suggest that estrogen exerts differential effects on the cAMP production in MCF7 cells, involving the activations Galpha(i) and Galpha(s) family of G proteins, depending on the length of time of hormone treatment.
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AMP Cíclico/biosíntesis , Estrógenos/farmacología , Línea Celular Tumoral , Colforsina/farmacología , Estradiol/análogos & derivados , Estradiol/farmacología , Antagonistas de Estrógenos/farmacología , Fulvestrant , Humanos , Líquido Intracelular/efectos de los fármacos , Líquido Intracelular/metabolismo , Toxina del Pertussis/farmacología , Factores de TiempoRESUMEN
Ginsenosides have demonstrated pharmacological effects in the central nervous, cardiovascular, and endocrine systems. We hypothesize that ginsenosides might mediate some of their actions by binding to the estrogen receptor, as they share many of the protective actions of estrogen in various physiological systems. The present study is aimed to determine whether ginsenoside Rg1 can act like an estrogen analog in stimulating human breast cancer cell growth as well as in the activation of estrogen response element-luciferase activity in HeLa cell. Rg1, but not its aglycone, stimulates [methyl-(3)H] thymidine incorporation in estrogen receptor-positive MCF-7 in a dose-dependent manner (10(-15)-10(-7) M). The stimulation of MCF-7 cell proliferation by 3 x 10(-13) M Rg1 can be blocked by 10(-6) M of the estrogen antagonist ICI 182780. Moreover, Rg1 stimulates estrogen response element-luciferase reporter gene activity in HeLa cells with an optimal dose of 3 x 10(-10) M. Such stimulation can also be blocked by 10(-6) M ICI 182780. In addition, Rg1 has no effect on [methyl-(3)H]thymidine incorporation in estrogen receptor-negative human breast cancer cells (MDA-MB-231). Furthermore, Rg1 failed to displace the specific binding of [(3)H]17 beta-estradiol to MCF-7 cell lysates, suggesting that no direct interaction of Rg1 with estrogen receptor is needed for its estrogenic action. Our results indicate that ginsenosides Rg1 has estrogen-like activity and should be classified as a novel class of potent phytoestrogen.