RESUMEN
Patients with central obesity have impaired insulin-stimulated vasodilation and increased ET-1 (endothelin 1) vasoconstriction, which may contribute to insulin resistance and vascular damage. Apelin enhances insulin sensitivity and glucose disposal but also acts as a nitric oxide (NO)-dependent vasodilator and a counter-regulator of AT1 (angiotensin [Ang] II type 1) receptor-induced vasoconstriction. We, therefore, examined the effects of exogenous (Pyr1)apelin on NO-mediated vasodilation and Ang II- or ET-1-dependent vasoconstrictor tone in obese patients. In the absence of hyperinsulinemia, forearm blood flow responses to graded doses of acetylcholine and sodium nitroprusside were not different during saline or apelin administration (both P>0.05). During intra-arterial infusion of regular insulin, however, apelin enhanced the vasodilation induced by both acetylcholine and nitroprusside (both P<0.05). Interestingly, the vasodilator effect of concurrent blockade of AT1 (telmisartan) and AT2 (PD 123,319) receptors was blunted by apelin (3±5% versus 32±9%; P<0.05). Similarly, during apelin administration, blockade of ETA receptors (BQ-123) resulted in lower vasodilator response than during saline (23±10% versus 65±12%; P<0.05). NO synthase inhibition by L-NMMA (l-N-monometylarginine) during the concurrent blockade of either Ang II or ETA receptors resulted in similar vasoconstriction in the absence or presence of apelin (P>0.05). In conclusion, in patients with central obesity, apelin has favorable effects not only to improve insulin-stimulated endothelium-dependent and endothelium-independent vasodilator responses but also to blunt Ang II- and ET-1-dependent vasoconstriction by a mechanism not involving NO. Taken together, our results suggest that targeting the apelin system might favorably impact some hemodynamic abnormalities of insulin-resistant states like obesity.
Asunto(s)
Anexinas/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Péptidos y Proteínas de Señalización Intercelular/farmacología , Obesidad/fisiopatología , Vasodilatación/efectos de los fármacos , Acetilcolina/farmacología , Adulto , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 2 de Angiotensina II/farmacología , Apelina , Bencimidazoles/farmacología , Benzoatos/farmacología , Femenino , Antebrazo/irrigación sanguínea , Humanos , Imidazoles/farmacología , Masculino , Persona de Mediana Edad , Óxido Nítrico/metabolismo , Nitroprusiato/farmacología , Piridinas/farmacología , Flujo Sanguíneo Regional/efectos de los fármacos , Telmisartán , omega-N-Metilarginina/farmacologíaRESUMEN
Esophageal squamous cell carcinoma (ESCC) is one of the most malignant cancers in Japan. Anticancer chemotherapy has been useful for ESCC treatment. However, therapeutic options are limited. Recently, bisphosphonates (BPs), which are osteoporosis drugs, have shown anticancer effects in several cancer cell lines, but the effects against ESCC cell lines are unknown. In this study, we examined the cytotoxic effects of BPs and their mechanisms of cytotoxicity in human ESCC cell lines. A first-generation BP (etidronate), two second-generation BPs (alendronate and pamidronate), and two third-generation BPs (risedronate and zoledronate) were used in this study. All BPs, except etidronate, were cytotoxic, as indicated by increased caspase-3/7 activity and numbers of Annexin-fluorescein isothiocyanate positive cells in ESCC cell lines. From cell cycle analysis, G0/G1-phase arrest was observed upon treatment with second- and third-generation BPs. In addition, Cyclin D1 protein expression levels were decreased by second- and third-generation BP treatment. Although squalene and trans, trans-farnesol minimally affected BP cytotoxicity, treatment with geranylgeraniol inhibited BP cytotoxicity almost completely. We concluded that second- and third-generation BPs are cytotoxic to ESCC cell lines as they induce apoptosis and inhibit the cell cycle through mevalonate pathway inhibition. Therefore, BP treatment may be a beneficial therapy in ESCC patients.
Asunto(s)
Apoptosis/efectos de los fármacos , Conservadores de la Densidad Ósea/farmacología , Carcinoma de Células Escamosas/patología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Difosfonatos/farmacología , Neoplasias Esofágicas/patología , Anexinas/efectos de los fármacos , Anexinas/metabolismo , Caspasa 3/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 7/efectos de los fármacos , Caspasa 7/metabolismo , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Ciclina D1/efectos de los fármacos , Ciclina D1/metabolismo , Diterpenos/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Carcinoma de Células Escamosas de Esófago , Farnesol/farmacología , Puntos de Control de la Fase G1 del Ciclo Celular/efectos de los fármacos , Humanos , Escualeno/farmacologíaRESUMEN
p21(waf 1/cip 1) (p21), best known for its ability to regulate the cell cycle, has been noted also to exert cell cycle-independent effects on apoptosis and differentiation. Inhibition of apoptosis by p21 has been reported in hematopoietic models, particularly in monocytes exposed to apoptogenic agents. The effect of p21 on survival has not hitherto been analyzed during the myeloblast to granulocyte transition. Using 32 Dc l3 murine myeloblasts, a cell line that proliferates in IL-3 and differentiates in G-CSF, we studied the effects of forced expression of p21 on cell survival. We hypothesized that exogenous p21 would suppress the modest levels of cell death associated with G-CSF-mediated differentiation of 32 Dc l3 cells. Contrary to expectations, we found that exogenous p21 enhanced apoptosis of cells removed from IL-3. The p21 overexpression led to decreased cell growth, caspase-3 activation and annexin positivity. These effects occurred only in the presence of G-CSF. These findings suggest that p21 is proapoptotic in granulopoiesis, and that this effect is masked by IL-3-mediated survival signals. Our results also indicate there are distinct and opposing effects of p21 on monocytic and granulocytic survival. Aberrantly high levels of p21 may contribute to disease processes involving excessive apoptosis of granulocyte precursors.
Asunto(s)
Apoptosis/fisiología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/farmacología , Granulocitos/fisiología , Animales , Anexinas/efectos de los fármacos , Anexinas/metabolismo , Apoptosis/efectos de los fármacos , Caspasa 3 , Caspasas/efectos de los fármacos , Caspasas/metabolismo , Ciclo Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Línea Celular , Proliferación Celular/efectos de los fármacos , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/antagonistas & inhibidores , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Regulación de la Expresión Génica , Factor Estimulante de Colonias de Granulocitos/farmacología , Granulocitos/citología , Granulocitos/efectos de los fármacos , Interleucina-3/farmacología , Ratones , Monocitos/efectos de los fármacos , Monocitos/fisiologíaRESUMEN
Recent insights in the role of ATP-binding cassette (ABC) transporters ABCG5 and ABCG8, the discovery of ezetimibe, the first approved direct cholesterol absorption inhibitor, as well as the identification of Niemann-Pick C1 Like 1 (NPC1L1) protein as sterol transporter in the gut, focused attention on sterol transport processes in the small intestine and the liver. The identification of defective structures in the ABCG5 or ABCG8 transporters in patients with the rare disease of sitosterolemia elucidated their role as sterol efflux pumps regulating at least in parts the intestinal sterol absorption and the hepatic sterol output. ABCG5 and ABCG8 themselves are regulated by cholesterol via liver X receptors (LXRs), which are also activated by oxysterols and some derivatives of plant sterols. NPC1L1 could recently be identified as a major sterol transporter for the intestinal uptake of cholesterol as well as plant sterols. Studies in NPC1L1 knockout mice indicate that this transporter is essential for the intestinal uptake of sterols and that NPC1L1 might also be involved in the mechanism of action of ezetimibe. However, studies with photoreactive cholesterol as well as with photoreactive ezetimibe analogues suggest that other processes might also be involved in the mechanism of action of ezetimibe.
Asunto(s)
Transportadoras de Casetes de Unión a ATP , Transportadoras de Casetes de Unión a ATP/fisiología , Anticolesterolemiantes/uso terapéutico , Azetidinas/farmacología , Colesterol , Lipoproteínas/fisiología , Fitosteroles/uso terapéutico , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5 , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8 , Transportadoras de Casetes de Unión a ATP/efectos de los fármacos , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Anexinas/efectos de los fármacos , Anexinas/metabolismo , Colesterol/metabolismo , Colesterol/fisiología , Ezetimiba , Humanos , Lipoproteínas/efectos de los fármacos , Lipoproteínas/metabolismo , Fitosteroles/metabolismoRESUMEN
BACKGROUND: Glucocorticoids attenuate the population of eosinophils and T lymphocytes in asthmatic airways. The decrease in airway eosinophilia is caused both by accelerated cell death and by induction of blockade of integrin adhesion. In this study, we examined the hypothesis that annexin 1 surface expression, which is upregulated by the glucocorticoid receptor, prevents integrin adhesion essential to cell migration by blocking intracellular translocation of cytosolic group IV phospholipase A2 (cPLA2). OBJECTIVE: To examine the relationship of the glucocorticoid on annexin 1 expression and the effect of blockade of annexin 1 activity on adhesion of human eosinophils in vitro. To determine the relationship between annexin 1surface expression and nuclear membrane translocation of cPLA2. METHODS: Eosinophils isolated from human peripheral blood were pretreated with fluticasone propionate (FP), and beta2-integrin adhesion was measured after stimulation with IL-5 or eotaxin. Effects of FP on cPLA2 expression, phosphorylation, and translocation were determined. The role of annexin 1 was examined by using annexin 1 blocking antibody and/or mimetic peptides. RESULTS: Fluticasone propionate decreased stimulated eosinophil adhesion and caused 4-fold increase in annexin 1 expression on the plasma membrane. Inhibition of adhesion by FP was blocked with annexin 1 blocking antibody. Annexin 1 N-terminal mimetic peptide also blocked beta2-integrin adhesion. Translocation of cPLA2 to the nuclear membrane was significantly blocked by incubation with FP. Blockade was reversed with annexin 1 blocking antibody. CONCLUSION: Blockade of beta2-integrin adhesion by glucocorticoid is regulated by annexin 1, which blocks cPLA2 translocation to nuclear membrane.
Asunto(s)
Anexinas/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Eosinófilos/efectos de los fármacos , Glucocorticoides/farmacología , Cadenas beta de Integrinas/metabolismo , Molécula 1 de Adhesión Intercelular/efectos de los fármacos , Fosfolipasas A/metabolismo , Androstadienos/farmacología , Anexinas/biosíntesis , Antiinflamatorios/farmacología , Biomarcadores , Western Blotting , Adhesión Celular/inmunología , Eosinófilos/inmunología , Eosinófilos/metabolismo , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Fluticasona , Fosfolipasas A2 Grupo IV , Humanos , Cadenas beta de Integrinas/efectos de los fármacos , Cadenas beta de Integrinas/inmunología , Molécula 1 de Adhesión Intercelular/inmunología , Molécula 1 de Adhesión Intercelular/metabolismo , Microscopía Fluorescente , Membrana Nuclear/efectos de los fármacos , Membrana Nuclear/inmunología , Membrana Nuclear/metabolismo , Fosfolipasas A2 , Fosforilación/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/inmunologíaRESUMEN
Exposure of erythrocytes to the Ca2+ ionophore ionomycin has recently been shown to induce cell shrinkage, cell membrane blebbing, and breakdown of phosphatidylserine asymmetry, all features typical of apoptosis of nucleated cells. Although breakdown of phosphatidylserine asymmetry is thought to result from activation of a Ca2+-sensitive scramblase, the mechanism and role of cell shrinkage have not been explored. The present study was performed to test whether ionomycin-induced activation of Ca2+-sensitive Gardos K+ channels and subsequent cell shrinkage participate in ionomycin-induced breakdown of phosphatidylserine asymmetry of human erythrocytes. According to on-cell patch-clamp experiments, ionomycin (1 microM) induces activation of inwardly rectifying K+-selective channels in the erythrocyte membrane. Fluorescence-activated cell sorter analysis reveals that ionomycin leads to a significant decrease of forward scatter, reflecting cell volume, an effect blunted by an increase of extracellular K+ concentration to 25 mM and exposure to the Gardos K+ channel blockers charybdotoxin (230 nM) and clotrimazole (5 microM). As reflected by annexin binding, breakdown of phosphatidylserine asymmetry is triggered by ionomycin, an effect again blunted, but not abolished, by an increase of extracellular K+ concentration and exposure to charybdotoxin (230 nM) and clotrimazole (5 microM). Similar to ionomycin, glucose depletion leads (within 55 h) to annexin binding of erythrocytes, an effect again partially reversed by an increase of extracellular K+ concentration and exposure to charybdotoxin. K-562 human erythroleukemia cells similarly respond to ionomycin with cell shrinkage and annexin binding, effects blunted by antisense, but not sense, oligonucleotides against the small-conductance Ca2+-activated K+ channel isoform hSK4 (KCNN4). The experiments disclose a novel functional role of Ca2+-sensitive K+ channels in erythrocytes, i.e., their participation in regulation of erythrocyte apoptosis.
Asunto(s)
Apoptosis/fisiología , Eritrocitos/patología , Ionomicina/farmacología , Ionóforos/farmacología , Canales de Potasio Calcio-Activados/fisiología , Anexinas/efectos de los fármacos , Anexinas/metabolismo , Apoptosis/efectos de los fármacos , Calcio/química , Calcio/metabolismo , Células Cultivadas , Eritrocitos/efectos de los fármacos , Eritrocitos/metabolismo , Citometría de Flujo , Humanos , Canales de Potasio de Conductancia Intermedia Activados por el Calcio , Células K562 , Oligodesoxirribonucleótidos Antisentido , Técnicas de Placa-Clamp , Fosfatidilserinas/metabolismo , Potasio/química , Potasio/metabolismo , Canales de Potasio/genéticaAsunto(s)
Antineoplásicos Hormonales/uso terapéutico , Glucocorticoides/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/metabolismo , Antagonistas de Andrógenos/metabolismo , Antagonistas de Andrógenos/farmacología , Antagonistas de Andrógenos/uso terapéutico , Anexinas/efectos de los fármacos , Anexinas/metabolismo , Antineoplásicos Hormonales/farmacología , Apoptosis/efectos de los fármacos , División Celular/efectos de los fármacos , Ensayos Clínicos como Asunto , Ensayos Clínicos Fase II como Asunto , Ensayos Clínicos Fase III como Asunto , Glucocorticoides/farmacología , Humanos , Masculino , Neoplasias Hormono-Dependientes/tratamiento farmacológico , Neoplasias Hormono-Dependientes/metabolismo , Neoplasias Hormono-Dependientes/fisiopatología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/fisiopatología , Estudios Retrospectivos , Transcripción Genética/efectos de los fármacos , Factor de Crecimiento Transformador beta/efectos de los fármacos , Factor de Crecimiento Transformador beta/metabolismo , Resultado del Tratamiento , Células Tumorales CultivadasRESUMEN
Several lines of evidence suggest that annexins, a family of phospholipid-binding proteins, play a role in cellular trafficking. Five annexins (I, II, V, VI, VII) were detected in rat adipose cells. They were primarily associated with the plasma membrane in a calcium-dependent manner. None of them redistributed with insulin treatment of the cells, in contrast to the glucose transporter GLUT4, which moved from intracellular membranes to the plasma membrane. Although the actual function of annexins in adipose cells remains to be determined, our data indicate that insulin-stimulated GLUT4 trafficking does not rely on a change in subcellular location of any of the five annexins detected so far in these cells.