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1.
Eur J Cancer ; 39(6): 829-37, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12651210

ABSTRACT

The identification of novel therapeutic agents for the management of malignant gliomas represents an area of active research. Here, we show that Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl; TPL), a stable nitroxide free radical, inhibits the growth of C6 glioma cells both in vitro and in vivo. Morphological features of apoptosis were apparent in C6 cells following in vitro treatment with TPL. Cell death was preceded by dose-dependent increase in p21(WAF1/CIP1) expression, without apparent stabilisation of the TP53 gene product. When C6 cells were grown as xenografts in nude mice, treatment with TPL induced a significant dose-dependent decrease in tumour growth, without signs of general or organ toxicity. Tumours from treated mice showed an increase in the number of apoptotic cells and a decrease in the rate of neo-vascularisation compared with tumours from control mice. Our findings suggest a potential use for TPL as a novel antiproliferative agent for the treatment of malignant gliomas.


Subject(s)
Central Nervous System Neoplasms/drug therapy , Cyclic N-Oxides/therapeutic use , Animals , Apoptosis , Blotting, Western , Central Nervous System Neoplasms/pathology , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/analysis , Drug Screening Assays, Antitumor , Immunohistochemistry , Mice , Neoplasm Transplantation , Rats , Spin Labels , Transplantation, Heterologous , Tumor Cells, Cultured , Tumor Suppressor Protein p53/analysis
2.
J Cell Biochem ; 82(2): 271-6, 2001.
Article in English | MEDLINE | ID: mdl-11527152

ABSTRACT

The piperidine nitroxide TEMPOL induces apoptosis in a number of tumor cell lines through free radical-dependent mechanisms. As mitochondria play a major role in apoptosis as both source and target for free radicals, the present study focuses on mitochondrial effects of TEMPOL in a human promyelocytic leukemic cell line (HL-60). On 24-h exposure to TEMPOL, the following alterations were observed: 1) decrease in both the intracellular and mitochondrial glutathione pools; 2) impairment of oxidative phosphorylation; and 3) decrease in mitochondrial membrane potential. In addition, TEMPOL was found to specifically target complex I of the respiratory chain, with minor effects on complexes II and IV, suggesting that mitochondrial effects might play a role in TEMPOL-induced oxidative stress and apoptosis, and that TEMPOL might sensitize tumor cells to the pro-apoptotic effects of cytotoxic agents.


Subject(s)
Antioxidants/pharmacology , Apoptosis/drug effects , Cyclic N-Oxides/pharmacology , HL-60 Cells/drug effects , Mitochondria/drug effects , Chromatography, High Pressure Liquid , Electron Transport Complex II , Electron Transport Complex III/antagonists & inhibitors , Electron Transport Complex IV/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Glutathione/metabolism , HL-60 Cells/cytology , Humans , Intracellular Membranes/drug effects , Membrane Potentials/drug effects , Multienzyme Complexes/antagonists & inhibitors , Neoplasm Proteins/antagonists & inhibitors , Oxidation-Reduction , Oxidative Phosphorylation/drug effects , Oxidoreductases/antagonists & inhibitors , Rotenone/pharmacology , Sodium Azide/pharmacology , Spin Labels , Succinate Dehydrogenase/antagonists & inhibitors
3.
Int J Oncol ; 18(6): 1245-9, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11351258

ABSTRACT

1-beta-D-arabinofuranosylcytosine (ara-C) is an antimetabolite used for the treatment of acute myelogenous leukemia. The ability of ara-C to kill neoplastic cells has been correlated to the induction of apoptosis. The clinical use of ara-C is limited by the development of drug resistance. Alterations in drug-induced apoptosis play a critical role in ara-C resistance. In particular, the proto-oncogene bcl-2 has been implicated in this phenomenon. To better understand the molecular basis of the role of bcl-2 in ara-C resistance, we investigated the relationship between the cytotoxic effect of ara-C, the expression levels and the subcellular localization of bcl-2 in three human leukemic cell lines (HL-60, KG1, J111). We have also evaluated the effects of ara-C on the J111 leukemic cell line (showing the lowest levels of Bcl-2 and the highest sensitivity to ara-C) overexpressing the bcl-2 oncogene. The model we developed here will allow further studies on the role of post-translational events involving bcl-2 (such as translocation and/or phosphorylation) in the cellular response to ara-C treatment.


Subject(s)
Antimetabolites, Antineoplastic/pharmacology , Cytarabine/pharmacology , HL-60 Cells/drug effects , Proto-Oncogene Proteins c-bcl-2/metabolism , Cell Survival/drug effects , DNA Fragmentation , Drug Resistance, Neoplasm , HL-60 Cells/metabolism , Humans , Isoenzymes/metabolism , Protein Kinase C/metabolism , Protein Kinase C-alpha , Proto-Oncogene Mas , Proto-Oncogene Proteins c-bcl-2/genetics , Transfection
4.
J Comp Neurol ; 229(1): 97-120, 1984 Oct 10.
Article in English | MEDLINE | ID: mdl-6490978

ABSTRACT

The major extrinsic projections to and from the visual and auditory cortical areas were examined in 4-day-old kittens using axonal transport of horseradish peroxidase (HRP) and/or tritiated proline. Six different afferent and seven different efferent systems were studied; all 13 were present by postnatal day 4 as revealed by either HRP, or autoradiography alone, or these two techniques combined. Topographical projections were found for the corticopetal pathways from the thalamus and claustrum and for the corticofugal pathways to the thalamus, claustrum, striatum, and tectum, as well as for the inter- and intrahemispheric pathways. No topographical relations were seen in projections to the cortex from the basal ganglia or the lower brainstem. The results of the present study indicate that most or all of the major extrinsic connections of the kitten's visual and auditory cortical areas are present neonatally, and that both the cells of origin and the axonal targets are arranged topographically much like those of adult cats. However, the origins of callosal projections from visual cortex are more widespread in newborn kittens than in adult cats. In addition, the laminar arrangements of the kitten's corticocortical connections differ from those of adult cats in a number of details. The results suggest that the sparing of some visual and auditory functions after neonatal lesions occurs despite the fact that the cortical areas removed have formed extrinsic connections.


Subject(s)
Auditory Cortex/anatomy & histology , Visual Cortex/anatomy & histology , Age Factors , Animals , Animals, Newborn , Basal Ganglia/anatomy & histology , Brain Stem/anatomy & histology , Cats , Neural Pathways/anatomy & histology , Superior Colliculi/anatomy & histology , Thalamic Nuclei/anatomy & histology
12.
Science ; 172(3980): 286-8, 1971 Apr 16.
Article in English | MEDLINE | ID: mdl-5548713

ABSTRACT

Unilateral ablation of the auditory cortex in the cat results in a profound deficit in attending to stimuli on the side contralateral to the lesion. The deficit is also manifested in an abnormal perception of left-right pulse pairs when the pulse which leads by a few milliseconds is contralateral to the damaged hemisphere.


Subject(s)
Auditory Cortex/physiology , Auditory Perception , Animals , Cats , Cerebral Decortication , Functional Laterality , Sound
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