RESUMEN
Anticancer effects of a common lipid-lowering drug, fenofibrate, have been described in the literature for a quite some time; however, fenofibrate has not been used as a direct anticancer therapy. We have previously reported that fenofibrate in its unprocessed form (ester) accumulates in the mitochondria, inhibits mitochondrial respiration, and triggers a severe energy deficit and extensive glioblastoma cell death. However, fenofibrate does not cross the blood brain barrier and is quickly processed by blood and tissue esterases to form the PPARα agonist fenofibric acid, which is practically ineffective effective in triggering cancer cell death. To address these issues, we have made several chemical modifications in fenofibrate structure to increase its stability, water solubility, tissue penetration, and ultimately anticancer potential. Our data show that, in comparison to fenofibrate, four new compounds designated here as PP1, PP2, PP3, and PP4 have improved anticancer activity in vitro. Like fenofibrate, the compounds block mitochondrial respiration and trigger massive glioblastoma cell death in vitro. In addition, one of the lead compounds, PP1, has improved water solubility and is significantly more stable when exposed to human blood in comparison to fenofibrate. Importantly, mice bearing large intracranial glioblastoma tumors demonstrated extensive areas of tumor cell death within the tumor mass following oral administration of PP1, and the treated mice did not show any major signs of distress, and accumulated PP1 at therapeutically relevant concentrations in several tissues, including brain and intracranial tumors.
RESUMEN
Fenofibrate, a well-known normolipidemic drug, has been shown to exert strong anticancer effects against tumors of neuroectodermal origin including glioblastoma. Although some pharmacokinetic studies were performed in the past, data are still needed about the detailed subcellular and tissue distribution of fenofibrate (FF) and its active metabolite, fenofibric acid (FA), especially in respect to the treatment of intracranial tumors. We used high performance liquid chromatography (HPLC) to elucidate the intracellular, tissue and body fluid distribution of FF and FA after oral administration of the drug to mice bearing intracranial glioblastoma. Following the treatment, FF was quickly cleaved to FA by blood esterases and FA was detected in the blood, urine, liver, kidney, spleen and lungs. We have also detected small amounts of FA in the brains of two out of six mice, but not in the brain tumor tissue. The lack of FF and FA in the intracranial tumors prompted us to develop a new method for intracranial delivery of FF. We have prepared and tested in vitro biodegradable poly-lactic-co-glycolic acid (PLGA) polymer wafers containing FF, which could ultimately be inserted into the brain cavity following resection of the brain tumor. HPLC-based analysis demonstrated a slow and constant diffusion of FF from the wafer, and the released FF abolished clonogenic growth of glioblastoma cells. On the intracellular level, FF and FA were both present in the cytosolic fraction. Surprisingly, we also detected FF, but not FA in the cell membrane fraction. Electron paramagnetic resonance spectroscopy applied to spin-labeled phospholipid model-membranes revealed broadening of lipid phase transitions and decrease of membrane polarity induced by fenofibrate. Our results indicate that the membrane-bound FF could contribute to its exceptional anticancer potential in comparison to other lipid-lowering drugs, and advocate for intracranial delivery of FF in the combined pharmacotherapy against glioblastoma.
Asunto(s)
Plásticos Biodegradables/farmacocinética , Neoplasias Encefálicas/tratamiento farmacológico , Encéfalo/metabolismo , Portadores de Fármacos/farmacocinética , Fenofibrato/análogos & derivados , Glioblastoma/tratamiento farmacológico , Animales , Encéfalo/efectos de los fármacos , Línea Celular Tumoral , Femenino , Fenofibrato/farmacocinética , Fenofibrato/farmacología , Humanos , Ácido Láctico/farmacocinética , Ratones , Ratones Desnudos , Ácido Poliglicólico/farmacocinética , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Polímeros/farmacocinética , Distribución TisularRESUMEN
Micro RNAs (miRNAs) are post-transcriptional modulators of gene expression that regulate the stability and translation of their target messenger RNAs (mRNAs). Here we report that the levels of a human brain-enriched miRNA-125b are up-regulated in interleukin-6 (IL-6)-stressed normal human astrocytes (NHA), a treatment known to induce astrogliosis. In vitro, anti-miRNA-125b added exogenously to IL-6-stressed NHA cultures attenuated both glial cell proliferation and increased the expression of the cyclin-dependent kinase inhibitor 2A (CDKN2A), a miRNA-125b target and negative regulator of cell growth. A strong positive correlation between miRNA-125b abundance and the glial cell markers glial fibrillary acidic protein (GFAP) and vimentin, and CDKN2A down-regulation was noted in advanced Alzheimer's disease (AD) and in Down's syndrome (DS) brain, chronic neurological disorders associated with astrogliosis. The results suggest that miRNA-125b up-regulation contributes to astrogliosis and to defects in the cell cycle that are characteristic of degenerating brain tissues.
Asunto(s)
Astrocitos/metabolismo , MicroARNs/biosíntesis , Actinas/metabolismo , Astrocitos/citología , Astrocitos/efectos de los fármacos , Proliferación Celular , Células Cultivadas , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Proteína Ácida Fibrilar de la Glía/metabolismo , Humanos , Interleucina-6/farmacología , MicroARNs/farmacología , Regulación hacia Arriba , Vimentina/metabolismoRESUMEN
High density micro-RNA (miRNA) arrays, fluorescent-reporter miRNA assay and Northern miRNA dot-blot analysis show that a brain-enriched miRNA-128 is significantly down-regulated in glioblastoma multiforme (GBM) and in GBM cell lines when compared to age-matched controls. The down-regulation of miRNA-128 was found to inversely correlate with WHO tumor grade. Three bioinformatics-verified miRNA-128 targets, angiopoietin-related growth factor protein 5 (ARP5; ANGPTL6), a transcription suppressor that promotes stem cell renewal and inhibits the expression of known tumor suppressor genes involved in senescence and differentiation, Bmi-1, and a transcription factor critical for the control of cell-cycle progression, E2F-3a, were found to be up-regulated. Addition of exogenous miRNA-128 to CRL-1690 and CRL-2610 GBM cell lines (a) restored 'homeostatic' ARP5 (ANGPTL6), Bmi-1 and E2F-3a expression, and (b) significantly decreased the proliferation of CRL-1690 and CRL-2610 cell lines. Our data suggests that down-regulation of miRNA-128 may contribute to glioma and GBM, in part, by coordinately up-regulating ARP5 (ANGPTL6), Bmi-1 and E2F-3a, resulting in the proliferation of undifferentiated GBM cells.
Asunto(s)
Angiopoyetinas/metabolismo , Neoplasias Encefálicas/patología , Encéfalo/patología , Proliferación Celular , Regulación hacia Abajo/fisiología , Factor de Transcripción E2F3/metabolismo , Glioblastoma/patología , MicroARNs/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Represoras/metabolismo , Adulto , Proteína 6 similar a la Angiopoyetina , Proteínas Similares a la Angiopoyetina , Angiopoyetinas/genética , Proliferación Celular/efectos de los fármacos , Biología Computacional/métodos , Regulación hacia Abajo/efectos de los fármacos , Factor de Transcripción E2F3/genética , Femenino , Humanos , Masculino , MicroARNs/genética , MicroARNs/farmacología , Persona de Mediana Edad , Proteínas Nucleares/genética , Complejo Represivo Polycomb 1 , Proteínas Proto-Oncogénicas/genética , ARN Mensajero/metabolismo , Proteínas Represoras/genética , Transfección/métodosRESUMEN
Glioblastoma multiforme (GBM) represents a class of malignant gliomas which rapidly proliferate, invade and destroy surrounding brain tissues. This study examined micro-RNA (miRNA) speciation and miRNA effects on gene expression in six ATCC glioma and GBM cell lines and in 14 glioma and GBM samples obtained from human brain biopsy. We observed selective up-regulation of miRNA-221 and down-regulation of a miRNA-221 messenger RNA target encoding the survivin-1 homolog BIRC1, a neuronal inhibitor of apoptosis protein (NIAP) and marker for neurodegeneration. The expression of BIRC5 (survivin-1) and caspase-3 were found to be significantly up-regulated, particularly in stage IV GBM. These studies suggest that the abundance and speciation of the BIRC family of neural cell fate regulators are differentially regulated in glioma and GBM, and may contribute to progressive changes in apoptotic signaling and altered neural cell cycling functions.
Asunto(s)
Caspasa 3/metabolismo , Regulación Neoplásica de la Expresión Génica/fisiología , Glioblastoma/metabolismo , MicroARNs/metabolismo , Proteína Inhibidora de la Apoptosis Neuronal/metabolismo , Adulto , Análisis de Varianza , Biopsia/métodos , Femenino , Glioblastoma/genética , Glioma/genética , Glioma/metabolismo , Humanos , Proteínas Inhibidoras de la Apoptosis , Masculino , MicroARNs/genética , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Persona de Mediana Edad , Proteína Inhibidora de la Apoptosis Neuronal/genética , ARN Mensajero/metabolismo , SurvivinRESUMEN
EEG monitoring was carried out by an EEG technician during 100 consecutive carotid endarterectomies in a community hospital. The technician's rating of the EEGs correlated with an inhouse electroencephalographer's interpretation and with historical published data. We conclude that intraoperative EEG monitoring during carotid endarterectomies can adequately be carried out by a competent EEG technician provided adequate physician backup and supervision are available.
Asunto(s)
Isquemia Encefálica/fisiopatología , Electroencefalografía , Endarterectomía Carotidea , Monitoreo Intraoperatorio , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
Cranioplasty represents a formidable challenge for neuro-surgeons, with a significant morbidity from both early and late wound infections. Polymethylmethacrylate (PMMA) is one of the most widely used materials in this setting. Despite the advantages of this material, such as ease of handling and inert biochemical properties, it is still a foreign body that is prone to infection. We present an animal model using a gentamicin-impregnated PMMA patch to assess the neurotoxicity as well as the efficacy of using this as an alternative material to lessen the infectious morbidity in this clinical setting. In part two of our experiment, we used a PMMA patch of similar weight and surface area in a physiological saline solution to determine the rate of gentamicin elution from the patch. The results obtained appear promising with no evidence of neurotoxicity and warrant further study to assess the clinical efficacy of PMMA in this setting.
Asunto(s)
Cementos para Huesos , Gentamicinas/efectos adversos , Metilmetacrilatos/administración & dosificación , Enfermedades del Sistema Nervioso/inducido químicamente , Cráneo/cirugía , Animales , Disponibilidad Biológica , Perros , Gentamicinas/administración & dosificaciónRESUMEN
Direct surgical attack on intracranial malformations of great complexity may be facilitated by complete cardiocirculatory arrest under hypothermia. To improve the technical aspects of this procedure and to determine the optimum depth of hypothermia, the duration of arrest that can be tolerated, and the role of barbiturate brain protection, we conducted an experimental study on 11 baboons. Arrest lasted for 45 or 90 minutes at a brain temperature of 12 degrees C. The animals were assessed by clinical, neuroradiological and necropsy examination. All 4 animals subjected to 45 minutes arrest made a good clinical recovery while 3 of the 7 subjected to 90 minutes arrest presented thromboembolic complications. Strict heparinization in the last 2 animals solved these problems. The findings of this study may help to make the procedure safer for clinical use.
Asunto(s)
Conducta Animal , Encéfalo/fisiopatología , Paro Cardíaco/fisiopatología , Hipotermia Inducida , Actividad Motora , Animales , Temperatura Corporal , Encéfalo/fisiología , Cognición , Electroencefalografía , Masculino , Papio , Factores de TiempoRESUMEN
Recurrent stenosis of the carotid arteries after a carotid endarterectomy for atherosclerosis can occur as a result of myointimal hyperplasia. This condition was treated by percutaneous transluminal angioplasty. Excellent dilatation of the vessel lumen was documented after balloon dilatation. A 6-month follow-up angiographic study, however, demonstrated recurrent high-grade stenosis at the same level in both carotid arteries. Presumably, the failure of percutaneous transluminal angioplasty and the treatment of myointimal hyperplasia of the internal carotid artery results in the same condition after the original endarterectomy, that is, additional myointimal hyperplasia.
Asunto(s)
Angioplastia de Balón , Enfermedades de las Arterias Carótidas/terapia , Enfermedades de las Arterias Carótidas/diagnóstico por imagen , Enfermedades de las Arterias Carótidas/patología , Arteria Carótida Interna/patología , Angiografía Cerebral , Humanos , Hiperplasia , Masculino , Persona de Mediana EdadRESUMEN
Patients with malignant gliomas are at increased risk for deep vein thrombophlebitis (DVT) and pulmonary embolism (PE). Difficult anticoagulation in cancer patients undergoing surgery, chemotherapy, or radiotherapy limit the choices of therapy for DVT. Interruption of the inferior vena cava with a Greenfield filter is a safe method of treating patients who have malignant gliomas and DVT with PE. We studied 23 patients treated for malignant gliomas; 16 were men and seven were women, with a mean age of 51 years (range, 26 to 78). Five patients had DVT shown by noninvasive blood flow studies, and four subsequently had PE, as demonstrated by ventilation perfusion lung scan; in one patient PE was diagnosed at autopsy. Of the 23 patients, four with postoperative craniotomy had DVT and all four had PE. Two of the five patients who received preoperative chemotherapy had DVT and three had PE. All patients with PE had a Greenfield filter placed in the inferior vena cava via the internal jugular vein without adverse sequelae.
Asunto(s)
Neoplasias Encefálicas/complicaciones , Glioma/complicaciones , Embolia Pulmonar/etiología , Tromboflebitis/etiología , Adulto , Anciano , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/terapia , Terapia Combinada , Craneotomía , Femenino , Filtración/instrumentación , Glioma/mortalidad , Glioma/terapia , Humanos , Masculino , Persona de Mediana Edad , Embolia Pulmonar/mortalidad , Embolia Pulmonar/prevención & control , Tromboflebitis/mortalidad , Tromboflebitis/prevención & controlRESUMEN
A case of eosinophilic granuloma of the cervical spine is described. Cervical radiography and computed tomography demonstrated destruction of pedicles and posterior portions of the neural arch. Vertebral body heights were essentially preserved and the importance of this finding is underscored. Computed tomography played an important role in evaluating the extent of this disease.