cytochalasin-b and Neuroblastoma

We describe a simple and widely applicable method to measure cell migration in time-lapse sequences of fluorescently labeled cells in culture. Briefly, binarized cell images obtained after thresholding were cumulatively projected, and the covered areas were measured. This procedure determines the time course of the track area successively covered by the cell population. Under conditions where cell growth is negligible, a robust index of cell motility is derived from normalized plots for the displacement of cells over time. We applied this method to quantitatively examine the migration of B35 neuroblastoma cells transiently expressing GFP and to C6 glioma cells after staining with Hoechst 33258. This sensitive assay detected the influence of agents which inhibit actin polymerization (cytochalasin B) or interfere with the maintenance of cell polarity (methyl-beta-cyclodextrin) on cell migration. Thus, this assay is a versatile tool to measure quickly the migration of different cell types using different labeling strategies.

Topics: Animals; beta-Cyclodextrins; Cell Line, Tumor; Cell Movement; Cytochalasin B; Glioma; Green Fluorescent Proteins; Microscopy, Fluorescence; Neuroblastoma; Neuroglia; Neurons; Rats

Neurons are terminally post-mitotic cells that utilize their microtubule arrays for the growth and maintenance of axons and dendrites rather than for the formation of mitotic spindles. Recent studies from our laboratory suggest that the mechanisms that organize the axonal and dendritic microtubule arrays may be variations on the same mechanisms that organize the mitotic spindle in dividing cells. In particular, we have identified molecular motor proteins that serve analogous functions in the establishment of these seemingly very different microtubule arrays. In the present study, we have sought to determine whether a non-motor protein termed NuMA is also a component of both systems. NuMA is a approximately 230 kDa structural protein that is present exclusively in the nucleus during interphase. During mitosis, NuMA forms aggregates that interact with microtubules and certain motor proteins. As a result of these interactions, NuMA is thought to draw together the minus-ends of microtubules, thereby helping to organize them into a bipolar spindle. In contrast to mitotic cells, post-mitotic neurons display NuMA both in the nucleus and in the cytoplasm. NuMA appears as multiple small particles within the somatodendritic compartment of the neuron, where its levels increase during early dendritic differentiation. A partial but not complete colocalization with minus-ends of microtubules is suggested by the distribution of the particles during development and during drug treatments that alter the microtubule array. These observations provide an initial set of clues regarding a potentially important function of NuMA in the organization of microtubules within the somatodendritic compartment of the neuron.

Topics: Animals; Antigens, Nuclear; Axons; Bucladesine; Cell Cycle; Cell Cycle Proteins; Cells, Cultured; Coculture Techniques; Cytochalasin B; Dendrites; Embryo, Mammalian; HeLa Cells; Hippocampus; Humans; Kinetics; Microtubules; Neuroblastoma; Neurons; Nocodazole; Nuclear Matrix-Associated Proteins; Nuclear Proteins; Paclitaxel; Rats; Spindle Apparatus; Sympathetic Nervous System; Tumor Cells, Cultured

In SH-SY5Y human neuroblastoma cells, addition of acetylcholine or carbachol rapidly induces a transient protrusion of lamellipodia. The protrusions appear after a delay of 30 sec and persist for a period of about 5 min at the margins of cell somata and at the distal parts of cell processes. They are caused by a strikingly increased, cytochalasin B-sensitive assembly of actin at the cell periphery. They often detach from the substrate, retracting and protruding again. In retinoic acid-induced neuronally differentiated cells, this initialized protrusive activity is restricted to growth cones. d-Tubocurarine does not influence, but atropine totally inhibits the cholinergic induction of the actin-driven protrusions, suggesting that a muscarinic receptor-mediated activation of the phosphoinositol signaling pathway is involved. Depolarization by increase of the potassium concentration and ionophore-mediated Ca(2+)-influx are ineffective to trigger the protrusive and ruffling activity. An identical cytochalasin B-sensitive actin-driven response is caused by treating of the cells with the protein kinase C (PKC) activator 12-myristate-13-acetate. In this case, however, lamellar protrusions are formed after a delay of at least 3 min and are maintained for several days. Incubating the cells with the protein kinase C inhibitor bisindolylmaleide or staurosporine inhibits both the muscarinic receptor-mediated and phorbolester-mediated actin-driven response, suggesting that activated PKC plays a crucial role.

Topics: Acetylcholine; Actins; Alkaloids; Carbachol; Cell Size; Culture Media; Cytochalasin B; Fluorescent Dyes; Humans; Indoles; Maleimides; Neurites; Neuroblastoma; Protein Kinase C; Receptors, Muscarinic; Receptors, Nicotinic; Signal Transduction; Staurosporine; Tetradecanoylphorbol Acetate; Time Factors; Tumor Cells, Cultured

L-Fucose is a monosaccharide normally present at low concentrations in serum and is the only levorotatory sugar utilized by mammalian systems. The metabolism of L-fucose is only partially understood. In this report, we characterize the uptake of L-fucose by four widely varying mammalian cell lines (murine neuroblastoma, bovine aortic endothelial, murine cerebral microvessel endothelial, and Madin-Darby canine kidney cells). Based on the criteria of saturability and specificity of L-fucose uptake, we conclude that L-fucose is accumulated via a specific recognition mechanism. Accumulation of L-fucose at 4 degrees C and in the presence of colchicine and cytochalasin D rules out receptor-mediated endocytosis as an uptake mechanism. Thus, the accumulation appears to be via a carrier system. Using a variety of criteria, we determined that L-fucose is not taken up by a glucose transporter system. Accumulation of L-[5,6-3H]fucose is Na(+)-independent and reduced by loading cells with L-fucose or depleting the cell of its phosphorylation capability, suggesting that the uptake of L-fucose is by passive facilitative diffusion. A significant amount of the L-fucose taken up by each of the four cell types was incorporated into protein and secreted into the medium.

Topics: Animals; Aorta; Biological Transport; Cattle; Cell Line; Cells, Cultured; Cerebrovascular Circulation; Cytochalasin B; Deoxyglucose; Diffusion; Dogs; Endothelium, Vascular; Fucose; Kidney; Kinetics; Mice; Microcirculation; Monosaccharides; Neuroblastoma; Phloretin; Phlorhizin; Tumor Cells, Cultured

The micronucleus (MN) test has been carefully characterized in four human tumour cell lines of widely differing radiosensitivity. Two radioresistant bladder carcinoma cell lines (MGH-U1 and RT112), one sensitive medulloblastoma cell line (D283MED) and a sensitive neuroblastoma cell line (HX142) were used. The number of MN per Gy of ionising radiation was 0.13 for HX142, 0.17 for D283MED, 0.21 for RT112 and 0.26 for MGH-U1. This does not rank the cell lines in the same order of radiosensitivity as clonogenic cell survival where the surviving fraction at 2 Gy (SF2) was 0.11 for HX142, 0.2 for D283MED, 0.62 for RT112 and 0.53 for MGH-U1. This discrepancy between MN formation and cell death leaves doubt as to the potential usefulness of the MN test as a rapid assay of radiosensitivity but it has potential implications for the mechanistic basis of radiosensitivity in these cells.

Topics: Cell Death; Cell Division; Cell Survival; Cytochalasin B; Humans; Medulloblastoma; Micronuclei, Chromosome-Defective; Neoplasms; Neuroblastoma; Radiation Tolerance; Tumor Cells, Cultured; Urinary Bladder Neoplasms

Our previous studies have demonstrated that the protein kinase inhibitor H-7 promotes neurite outgrowth from mouse neuroblastoma N18TG2 cells as well as from primary cerebellar cells, and also that the neurites induced by H-7 were more tolerant of colchicine (COL) than those induced by dibutyryl cAMP (dB-cAMP). In the present study, we tested the effects of H-7 and dB-cAMP on neurite growth from N18TG2 cells in the presence of COL. We found that only H-7 promoted neurite formation in the presence of COL. The percentage of cells with neurites induced by H-7 in the presence of COL (H-7 + COL) was similar to that induced by H-7 alone. The neurites induced by H-7 + COL grew straight. They were very thin (less than 1 micron in diameter) and had round varicosities, as did the neurites induced by H-7 alone. By transmission electron microscopy, the neurites induced by H-7 + COL were found to contain longitudinally arranged intermediate filaments (IF). Microtubules (MT) were not observed within the neurites. We also examined the effect of cytochalasin B (CB) on the neurites induced by H-7 + COL and by H-7 alone. The neurites induced by H-7 + COL were tolerant to CB, but those induced by H-7 were resorbed completely within 24 h after CB was applied. Neurites tolerant to CB contained longitudinally IF. Simultaneous application of CB with H-7 + COL or with H-7 alone did not induce neurite formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Colchicine; Cytochalasin B; Isoquinolines; Neurites; Neuroblastoma; Piperazines; Protein Kinase Inhibitors; Tumor Cells, Cultured

Cultured neuroblastoma, cerebral microvessel endothelial, and retinoblastoma cells were used to examine the mechanism of acute inhibition by D-glucose of myo-inositol uptake. Acute exposure of the cells to 30 mM D-glucose caused a significant decrease in Na(+)-dependent myo-inositol uptake in all three cell types. The effect of D-glucose to acutely inhibit myo-inositol uptake was dependent on the extracellular glucose concentration and was not reversed by sorbinil. 2-Deoxy-D-glucose (30 mM), 3-O-methyl-D-glucose (30 mM), and cytochalasin B (100 microM) did not acutely inhibit myo-inositol uptake. These data suggest that the hydroxyl groups on carbons 2 and 3 of D-glucose, which in a Haworth projection appear trans to each other, are important for inhibitory activity. Other monosaccharides (30 mM) having a similar 2,3-trans-diol configuration, L-glucose, D- and L-fucose, D- and L-galactose, D- and L-xylose, and D-arabinose, all to varying degrees significantly inhibited myo-inositol uptake. In all cases, the L-isomers were more potent inhibitors of myo-inositol uptake than the corresponding D-isomers. Monosaccharides (30 mM) having hydroxyl groups on carbons 2 and 3 in a cis configuration, D-mannose, L-rhamnose, D-allose, and D-ribose, did not acutely inhibit myo-inositol uptake. Replacing the hydroxyl group with a fluorine on carbons 2 or 3 of D-glucose negated its inhibitory activity of myo-inositol uptake. In contrast, replacing the hydroxyl group with a fluorine on carbon 6 of D-glucose did not block its inhibition of myo-inositol uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 3-O-Methylglucose; Animals; Biological Transport; Carbohydrate Conformation; Cell Line; Cytochalasin B; Deoxyglucose; Endothelium, Vascular; Glucose; Inositol; Kinetics; Methylglucosides; Mice; Molecular Structure; Neuroblastoma; Phlorhizin; Sodium

Inositol uptake was studied in the rat CNS neuroblastoma B50 cell line. Eadie-Hofstee analysis of the uptake pattern reveals two defined modes of inositol entry into the cell. The high-affinity uptake component requires the presence of extracellular sodium and is inhibited by phloridzin. Analysis of the uptake velocities of the high-affinity uptake component provided the following apparent kinetic parameters: Km = 13.7 microM and Vmax = 14.7 pmol/mg of protein/min (without correcting for residual diffusion) and Km = 12.9 microM and Vmax = 12.3 pmol/mg of protein/min (with correction). At physiological concentrations, the high-affinity transport process contributes approximately 70% to total uptake; the remainder is due to a low-affinity diffusion-like process. Uptake inhibition studies reveal that the uptake process is sensitive to ouabain, amiloride, and dichlorobenzamil inhibition but relatively insensitive to cytochalasin B or phloretin. When neuroblastoma B50 cells are induced to differentiate morphologically with high extracellular calcium or with dibutyryl cyclic AMP, a significant decrease in inositol uptake is observed. The dibutyryl cyclic AMP-mediated inhibition of uptake affects only the high-affinity uptake component and is noncompetitive in nature. The high extracellular calcium-mediated inhibition is less specific; it involves "disappearance" of the high-affinity process, some inhibition of the low-affinity process, and an increase of inositol efflux. The significance of these observations is discussed in the context of neuroblastoma B50 cell differentiation.

Topics: Amiloride; Animals; Biological Transport; Bucladesine; Calcium; Cell Differentiation; Cytochalasin B; Inositol; Kinetics; Neuroblastoma; Ouabain; Phloretin; Phlorhizin; Rats; Sodium; Tumor Cells, Cultured

Ionophore (A23187)-mediated calcium influx induced rapid neurite outgrowth in NB2a/d1 cells. This outgrowth was prevented by colchicine but not by cycloheximide, demonstrating a requirement for microtubule assembly but not de novo synthesis. Cytochalasin B induced rapid, colchicine-sensitive outgrowth, indicating that depolymerization of the submembrane actin network may be sufficient to allow neurite outgrowth under conditions which permitted microtubule assembly. Neurites induced by serum-deprivation or calcium influx were rapidly retracted by colchicine unless cytochalasin B was first added, indicating that the actin network may provide the retractile force which mediates neurite retraction following microtubule depolymerization. We conclude that neurite outgrowth can be initiated in NB2a/d1 cells by calcium influx, and may involve alterations in actin and microtubule dynamics.

Topics: Actins; Animals; Axons; Calcimycin; Calcium; Cell Differentiation; Colchicine; Cycloheximide; Cytochalasin B; Cytoskeleton; Mice; Microtubules; Neuroblastoma; Tubulin; Tumor Cells, Cultured

The effect in vitro of some cytoplasmic structure and function inhibitors on the different stages of rabies virus infection was investigated. Treatment of fibroblasts (CER) and human neuroblastoma cells (IMR-32) with substances acting on low pH intracellular compartments (methylamine and monensin) prevented rabies virus genome delivery in the cytosol. An early inhibition of viral infection was also obtained in the presence of B and D cytochalasins and trifluoperazine which interact with microfilament structures. Treatment with colchicine and vinblastine did not affect rabies multiplication, suggesting that microtubules are not involved in this process. However, the multiplication of prebound virions did not take place in the presence of inhibitors of oxidative phosphorylation (sodium azide and CCCP) and of glycolysis (2-deoxy-D-glucose) indicating that rabies virus replication is largely energy-dependent in both host cells examined.

Topics: Animals; Azides; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Cell Line; Colchicine; Cytochalasin B; Cytochalasin D; Deoxyglucose; Dose-Response Relationship, Drug; Fibroblasts; Humans; Methylamines; Monensin; Neuroblastoma; Rabies virus; Sodium Azide; Trifluoperazine; Tumor Cells, Cultured; Vinblastine; Virus Replication

Undifferentiated NG108-15 cells, when replated onto laminin-coated substrata, extend multipolar, highly branched neurite-like extensions up to 200 microns in length within 4 h; morphologic and pharmacologic properties of these 'rapid-onset neurites' have been described recently. The present study has extended these observations, using time lapse video recordings of their dynamic behavior and additional pharmacologic studies. Rapid-onset neurites and neuronal growth cones were shown to be regulated in an identical manner in all respects examined, including inhibition of outgrowth by cytochalasin B. Of particular interest was the observation that rapid-onset neurites in contact with laminin exhibited an extremely high rate of turnover, which was inhibited by 5'-deoxy-5'-methylthioadenosine (MTA). This system provides a uniquely favorable in vitro preparation in which neuritic plasticity can be elicited, directly observed and experimentally modulated under controlled conditions.

Topics: Adenosine; Animals; Cell Differentiation; Cells, Cultured; Cytochalasin B; Dendrites; Deoxyadenosines; Glioma; Laminin; Neuroblastoma; Thionucleosides; Time Factors; Tumor Cells, Cultured

Motility of neuroblastoma cells in the culture of cell line C-1300, clone N-18-A was investigated microcinematographically. In the course of morphological differentiation of the cells, after cytochalasin B treatment (1.8 mkg/ml for 24 hours), in some differentiated cells a special type of movement of the cytoplasmic mass together with the nucleus along elongated pseudopodia was detected. Such a type of movement has never been described. Sometimes, a shift in the nucleus position resulted in the complete change or reversion of cell polarity. The phenomenon of cell nucleus displacement relative to the cell configuration or reversion of the cell polarity can possibly play an important functional role for neural cells.

Topics: Animals; Cell Line; Cell Movement; Cell Nucleus; Cell Transformation, Neoplastic; Cytochalasin B; Cytoplasm; Mice; Neuroblastoma; Pseudopodia; Tumor Cells, Cultured

Identification of hexose transporter sites by cytochalasin B binding was conducted with a centrifugation assay. The determination of KD and Bmax values by LIGAND computer analysis provided binding data that are similar in primary astrocytes (238 nM and 14 pmol/mg protein) and neuroblastoma cells (179 nM and 13.6 pmol/mg protein). In contrast, only an insignificant number of transporter sites was detectable in C6 glioma cells, irrespective of whether membrane fractions were obtained by a two-phase polymer system or by a latex phagocytosis technique yielding inside-out plasma membranes. The latter membrane preparation was utilized to identify and quantitate the transporter molecules at the inner membrane surface of primary astrocytes, i.e., 160 nM (KD) and 5.8 pmol/mg protein (Bmax), respectively.

Topics: Animals; Astrocytes; Binding, Competitive; Cell Line; Cell Membrane; Cytochalasin B; Glioma; Kinetics; Monosaccharide Transport Proteins; Neuroblastoma; Neurons

Neuroblastoma and glioma cells were grown in the presence of [3H]galactose, and the incorporation of 3H into gangliosides and the transport of newly synthesized gangliosides to the cell surface were examined under different experimental conditions. A variety of drugs, including inhibitors of protein synthesis and energy metabolism, modulators of the cytoskeleton and the ionophore monensin, had no effect on the transport of newly synthesized GD1a in neuroblastoma cells. Only low temperature effectively blocked translocation to the plasma membrane. Monensin, however, had marked effects on the biosynthesis of gangliosides and neutral glycosphingolipids. Whereas incorporation of 3H into complex glycosphingolipids was reduced, labeling of glucosylceramide was increased in cells exposed to monensin. In addition, biosynthesis of the latter glycolipid was less susceptible to low temperatures than that of more complex ones. Previous studies have implicated the Golgi apparatus as the predominant site of glycosylation of gangliosides. As monensin has been reported to interfere with the Golgi apparatus, our results indicate that glucosylceramide may be synthesized at a site that is separate from the site where further glycosylation occurs. Once synthesis of a ganglioside is completed, transport of the molecule to the cell surface proceeds under conditions of cytoskeletal disruption, energy depletion and ionic inbalance , but not low temperature.

Topics: Animals; Biological Transport; Cells, Cultured; Colchicine; Cycloheximide; Cytochalasin B; Glioma; Glycosphingolipids; Golgi Apparatus; Ionophores; Mice; Monensin; Neuroblastoma; Puromycin; Rats; Temperature; Vinblastine

These studies demonstrate that while microtubules are essential for BBG-mediated neurite initiation and elongation, they are not involved in microfilament-dependent ganglioside-mediated surface activity. Microfilaments may be more directly altered by exogenous gangliosides than microtubules since they are the major structural elements of microvilli and are required for neurite branching. Our studies suggest that normal neuritogenesis requires a delicately balanced interaction between various cytoskeletal elements. Since there is a close relationship between membrane-associated lipid molecules and submembranous cytoskeletal elements, the incorporation of gangliosides into membranes may alter this balance and result in neurite formation. The use of gangliosides to enhance neurite production provides a unique model for the study of nerve development. We have shown that bovine brain gangliosides stimulate an immediate sequence of surface-related changes as well as microtubule and microfilament dependent neurite formation in Neuro-2a cells. However, the precise molecular events by which gangliosides enhance neuritogenesis await further study.

Topics: Animals; Axons; Brain; Cattle; Cell Line; Cytochalasin B; Demecolcine; Gangliosides; Mice; Microscopy, Electron; Microscopy, Electron, Scanning; Microvilli; Neuroblastoma; Neurons

The action of cytochalasin B (CB) on the differentiation of cultured neuroblastoma cells has been studied. CB treatment (1.8 micrograms/ml for 3 days) blocked cytokinesis, leading to the multinucleation of neuroblastoma cells. The replacement of medium with CB by standard medium without CB led to the improvement of cell spreading on the substrate and to the appearance of 43.7 +/- 4.1% of morphologically differentiated cells. 4.7 +/- 0.6% of differentiated cells formed in CB-untreated control cultures. Thus, incubation with CB followed by the agent removal from the medium induced the differentiation of neuroblastoma cells. A possible role of multinucleation in this process is discussed.

Topics: Animals; Cell Differentiation; Cells, Cultured; Cytochalasin B; Mice; Neoplasms, Experimental; Neuroblastoma

1. The changes of voltage-gated ion channels in the mouse oocyte after fertilization were investigated under voltage clamp.2. About 60 min after introduction of sperm suspension into the fertilization medium, the amplitude of inward current through Ca(2+)-channels increased, which occurred at anaphase during the second meiotic division. The peak amplitude of the maximum inward current per unit membrane capacity of the oocytes at metaphase was 20+/-3 muA/muF in 50 mM-Sr medium. It was 28+/-8 muA/muF at anaphase, and 32+/-5 muA/muF at telophase. The kinetic properties as well as selectivity among Ca, Sr and Mn ions were not altered after fertilization.3. The outward surge current which was found at the higher membrane potential over +50 mV also increased in amplitude after fertilization, simultaneously with the increase in amplitude of inward current through Ca(2+)-channels. The means and the standard deviations of the surge current per unit membrane capacity at 120 mV were 31+/-8 muA/muF at metaphase, and 48+/-7 muA/muF at telophase. The kinetic properties of the outward surge current were not altered after fertilization.4. Application of colcemid (10(-7) mole/l.) or cytochalasin B (2 x 10(-5) mole/l.) did not prevent the increase in amplitude of both inward current through Ca channels and the outward surge current.5. The membrane currents in N-18 mouse neuroblastoma cells in logarithmic growth phase were examined under voltage clamp. The N-18 neuroblastoma cells possessed the Ca inward current and the delayed outward current. The kinetic properties and the steady-state inactivation of Ca(2+)-channels in N-18 neuroblastoma cells were compared with those in mouse oocytes. It was concluded that they could be regarded as identical between the mouse oocyte and the N-18 neuroblastoma cell.

Topics: Animals; Calcium; Cell Division; Cells, Cultured; Cytochalasin B; Female; Fertilization in Vitro; Ion Channels; Manganese; Membrane Potentials; Mice; Neoplasms, Experimental; Neuroblastoma; Oocytes; Ovum; Strontium

Methylmercury was taken up preferentially by mouse glioma and mouse neuroblastoma cells relative to inorganic mercury. Methylmercury uptake was depressed by lowering the cellular ATP level or the incubation temperature, while the uptake of inorganic mercury was not affected by these treatments. When the cells were treated with reagents such as cytochalasin B, colchicine and vinblastine which are known to affect membrane permeability, changes in permeability to methylmercury caused by these reagents were markedly different from those to inorganic mercury. Inorganic mercury above 2 x 10(-5)M caused the release of 2-deoxyglucose trapped in the cells and the amount of inorganic mercury taken up by the cells increased markedly at higher concentrations. Inorganic mercury thus appeared to move into the cells after disrupting the membrane barrier, while methylmercury can penetrate the cells without any noticeable damage to the barrier.

Topics: Animals; Cells, Cultured; Colchicine; Cytochalasin B; Deoxyglucose; Glioma; Mercury; Methylmercury Compounds; Mice; Neoplasms, Experimental; Neuroblastoma; Vinblastine

When neuroblastoma cells bearing neurites are incubated with colchicine or Nocodazole, the cytoplasmic microtubules are depolymerized and concomitantly the neurites retract. We report here that cytochalasin separates the two effects of these drugs: it quantitatively inhibits neurite retraction but does not inhibit microtubule assembly. The neurites that remain contain intermediate filaments and actin but are devoid of microtubules. Depletion of cellular ATP also blocks neurite retraction induced by colchicine or Nocodazole, but some assembled microtubules persist under these conditions. The results suggest that neurite retraction is an active cell process.

Topics: Actins; Animals; Antineoplastic Agents; Benzimidazoles; Carbamates; Cell Line; Colchicine; Cytochalasin B; Cytochalasin D; Cytochalasins; Fluorescent Antibody Technique; Mice; Microscopy, Electron; Microtubules; Neoplasms, Experimental; Neuroblastoma; Nocodazole; Tubulin

The site of plasminogen activator release by differentiated neuroblastoma clonal cell lines was determined with a fibrin overlay assay. Release of plasminogen activator was seen at the growth cone in 72 percent of the cells bearing neurites. For 21 percent of these cells the growth cone was the predominant or exclusive site of this enzyme activity. Selective release of protease at the "trailblazing" tip of the neurite may be important in neuron migration and neurite growth in vivo.

Topics: Animals; Cell Differentiation; Cell Line; Cell Movement; Cytochalasin B; Fibroblasts; Mice; Neuroblastoma; Neurons; Plasminogen Activators; Secretory Rate

Topics: Animals; Antigens; Cell Adhesion; Cell Survival; Clone Cells; Cytochalasin B; Cytotoxicity, Immunologic; Edetic Acid; In Vitro Techniques; Lymphocytes; Male; Mice; Neuroblastoma; Rosette Formation; Temperature

The release of acetylcholinesterase from neurons was studied using cultured chick-embryo spinal-cord cells. Cells dissociated from 12-day-old chick-embryo spinal cords were grown in culture for 10-12 days. Numerous well differentiated spinal neurons were found after 7-10 days in culture. Acetylcholinesterase activity per dish increased by 60-fold from days 2-12. Acetylcholinesterase was released into the surrounding media by the cells when they were incubated either in the standard culture medium or the serum-free medium. Acetylcholinesterase release was significantly reduced when protein synthesis and microtubules were disrupted by cycloheximide and colchicine, respectively. Histochemical localization of acetylcholinesterase indicated that the synthesis and relase of acetylcholinesterase are attributable to neurons. Cultured chick-embryo brain and neuroblastoma cells also released acetylcholinesterase into the media. These results are discussed with regard to possible physiological roles for acetylcholinesterase secretion from neurons.

Topics: Acetylcholinesterase; Animals; Brain; Cells, Cultured; Chick Embryo; Colchicine; Cycloheximide; Cytochalasin B; Neuroblastoma; Spinal Cord

Sodium butyrate produces reversible changes in morphology, growth rate, and enzyme activities of several mammalian cell types in culture. Some of these changes are similar to those produced by agents which increase the intracellular level of adenosine 3',5'-cyclic monophosphate (cAMP) or by analogs of cAMP. Sodium butyrate increases the intracellular level of cAMP by about two fold in neuroblastoma cells; therefore, some of the effects of sodium butyrate on these cells may in part be mediated by cAMP. Sodium butyrate appears to have properties of a good chemotherapeutic agent for neuroblastoma tumors because the treatment of neuroblastoma cells in culture causes cell death and "differentiation"; however, it is either innocuous or produces reversible morphological and biochemical alterations in other cell types.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Acetylcholinesterase; Adenylate Kinase; Anti-Bacterial Agents; Bucladesine; Butyrates; Caproates; Cell Differentiation; Cell Division; Cell Line; Cell Transformation, Neoplastic; Cells, Cultured; Cyclic AMP; Cytochalasin B; DNA; HeLa Cells; Humans; Neuroblastoma; Parabens; Propionates; Proteins; RNA; Transferases; Tyrosine 3-Monooxygenase; Vinblastine

At 2 degrees, murine C1300 neuroblastoma cells bound NGF-coated sheep erythrocytes and formed rosettes. When the temperature was raised to 37 degrees, the neuroblastoma cells underwent a rapid transformation characterized by microtubule formation, which occurred under the membrane surface close to the points of contact with the attached red cells. Cytoplasmic processes filled wit- microtubules were then emitted by the cell body and surrounded the red cells. Within 20 to 30 min, the attached erythrocytes were phagocytized. Interiorization of membrane-bound erythrocytes-antibody-complement complexes by neuroblasto-a cells could be similarly induced at 37 degrees. In both cases, the extent of phagocytosis was decreased when microtubule formation was blocked with colchicine or vinblastine. Complete inhibition was obtained only by pretreatment of cells with cytochalasin B, a strong inhibitor of microfilament contraction. The role played by the microtubules and the microfilaments in promoting the phagocytosis of the attached erythrocytes is discussed.

Topics: Animals; Binding Sites; Cell Membrane; Clone Cells; Colchicine; Complement System Proteins; Cytochalasin B; Cytoplasm; Erythrocytes; Immune Adherence Reaction; Mice; Microtubules; Neoplasms, Experimental; Nerve Growth Factors; Neuroblastoma; Phagocytosis; Sheep; Temperature; Vinblastine

Topics: Animals; Axons; Bucladesine; Cell Differentiation; Cell Division; Cell Line; Cell Nucleus; Clone Cells; Cytochalasin B; Mice; Neuroblastoma; Stimulation, Chemical; Ultracentrifugation