scholarly journals Influence of the centrosome on the structure of nucleated microtubules.

1985 ◽  
Vol 100 (4) ◽  
pp. 1185-1191 ◽  
Author(s):  
L Evans ◽  
T Mitchison ◽  
M Kirschner
Keyword(s):  
Lattice Structure ◽  
Neuroblastoma Cells ◽  
Nucleation Sites ◽  
Self Assembled ◽  
Brain Microtubules

The capacity of the centrosome to influence the lattice structure of nucleated microtubules was studied in vitro. Brain microtubules self-assembled to give predominantly (98%) 14-protofilament microtubules. However, under exactly the same conditions of assembly they grew off of purified centrosomes from neuroblastoma cells to give mostly (82%) 13-protofilament microtubules. Thus, the nucleation sites on the centrosome constrained the microtubule lattice to yield the number of protofilaments usually found in vivo.

In-vitro- und In-vivo-Wirkung von Schilddrüsenhormon auf das Wachstum von Neuroblastomzellen

1990 ◽  
Vol 29 (03) ◽  
pp. 120-124
Author(s):  
R. P. Baum ◽  
E. Rohrbach ◽  
G. Hör ◽  
B. Kornhuber ◽  
E. Busse
Keyword(s):  
Cell Differentiation ◽  
Neuroblastoma Cells ◽  
Control Group ◽  
Initial Value ◽  
Initial Rise ◽  
Biphasic Effect ◽  
Contrast Microscopy ◽  
Morphological Sign

The effect of triiodothyronine (T3) on the differentiation of cultured neuroblastoma (NB) cells was studied after 9 days of treatment with a dose of 10-4 M/106 cells per day. Using phase contrast microscopy, 30-50% of NB cells showed formation of neurites as a morphological sign of cellular differentiation. The initial rise of the mitosis rate was followed by a plateau. Changes in cyclic nucleotide content, in the triphosphates and in the activity of the enzyme ornithine decarboxylase (ODC) were assessed in 2 human and 2 murine cell lines to serve as biochemical parameters of the cell differentiation induced by T3. Whereas the cAMP level increased significantly (3 to 7 fold compared with its initial value), the cGMP value dropped to 30 to 50% of that of the control group. ATP and GTP increased about 200%, the ODC showed a decrease of about 50%. The present studies show a biphasic effect of T3 on neuroblastoma cells: the initial rise of mitotic activity is followed by increased cell differentiation starting from day 4 of the treatment.

Molecular iodine synergized and sensitized neuroblastoma cells to the antineoplastic effect of ATRA

2020 ◽  
Vol 27 (12) ◽  
pp. 699-710
Author(s):  
Irasema Mendieta ◽  
Gabriel Rodríguez-Gómez ◽  
Bertha Rueda-Zarazúa ◽  
Julia Rodríguez-Castelán ◽  
Winniberg Álvarez-León ◽  
...  
Keyword(s):  
Residual Disease ◽  
Neuroblastoma Cells ◽  
Survivin Expression ◽  
Body Weight Loss ◽  
Immunohistochemical Analysis ◽  
Molecular Iodine ◽  
Tyrosine Kinase Receptor ◽  
Adjuvant Effect

Neuroblastoma (NB) is the most common solid childhood tumor, and all-trans retinoic acid (ATRA) is used as a treatment to decrease minimal residual disease. Molecular iodine (I2) induces differentiation and/or apoptosis in several neoplastic cells through activation of PPARγ nuclear receptors. Here, we analyzed whether the coadministration of I2 and ATRA increases the efficacy of NB treatment. ATRA-sensitive (SH-SY5Y), partially-sensitive (SK-N-BE(2)), and non-sensitive (SK-N-AS) NB cells were used to analyze the effect of I2 and ATRA in vitro and in xenografts (Foxn1 nu/nu mice), exploring actions on cellular viability, differentiation, and molecular responses. In the SH-SY5Y cells, 200 μM I2 caused a 100-fold (0.01 µM) reduction in the antiproliferative dose of ATRA and promoted neurite extension and neural marker expression (tyrosine hydroxylase (TH) and tyrosine kinase receptor alpha (Trk-A)). In SK-N-AS, the I2 supplement sensitized these cells to 0.1 μM ATRA, increasing the ATRA-receptor (RARα) and PPARγ expression, and decreasing the Survivin expression. The I2 supplement increased the mitochondrial membrane potential in SK-N-AS suggesting the participation of mitochondrial-mediated mechanisms involved in the sensibilization to ATRA. In vivo, oral I2 supplementation (0.025%) synergized the antitumor effect of ATRA (1.5 mg/kg BW) and prevented side effects (body weight loss and diarrhea episodes). The immunohistochemical analysis showed that I2 supplementation decreased the intratumoral vasculature (CD34). We suggest that the I2 + ATRA combination should be studied in preclinical and clinical trials to evaluate its potential adjuvant effect in addition to conventional treatments.

scholarly journals Effect of ethanol and cocaine on [11C]MPC-6827 uptake in SH-SY5Y cells

2021 ◽  
Author(s):  
Naresh Damuka ◽  
Miranda Orr ◽  
Paul W. Czoty ◽  
Jeffrey L. Weiner ◽  
Thomas J. Martin ◽  
...  
Keyword(s):  
Mechanism Of Action ◽  
Ex Vivo ◽  
Neuroblastoma Cells ◽  
Proper Function ◽  
Brain Functions ◽  
Biodistribution Studies ◽  
Positron Emission ◽  
Vitro Binding

AbstractMicrotubules (MTs) are structural units in the cytoskeleton. In brain cells they are responsible for axonal transport, information processing, and signaling mechanisms. Proper function of these processes is critical for healthy brain functions. Alcohol and substance use disorders (AUD/SUDs) affects the function and organization of MTs in the brain, making them a potential neuroimaging marker to study the resulting impairment of overall neurobehavioral and cognitive processes. Our lab reported the first brain-penetrant MT-tracking Positron Emission Tomography (PET) ligand [11C]MPC-6827 and demonstrated its in vivo utility in rodents and non-human primates. To further explore the in vivo imaging potential of [11C]MPC-6827, we need to investigate its mechanism of action. Here, we report preliminary in vitro binding results in SH-SY5Y neuroblastoma cells exposed to ethanol (EtOH) or cocaine in combination with multiple agents that alter MT stability. EtOH and cocaine treatments increased MT stability and decreased free tubulin monomers. Our initial cell-binding assay demonstrated that [11C]MPC-6827 may have high affinity to free/unbound tubulin units. Consistent with this mechanism of action, we observed lower [11C]MPC-6827 uptake in SH-SY5Y cells after EtOH and cocaine treatments (e.g., fewer free tubulin units). We are currently performing in vivo PET imaging and ex vivo biodistribution studies in rodent and nonhuman primate models of AUD and SUDs and Alzheimer's disease.

Self-assembled drug delivery systems. Part 6: In vitro/in vivo studies of anticancer N-octadecanoyl gemcitabine nanoassemblies

2012 ◽  
Vol 430 (1-2) ◽  
pp. 276-281 ◽  
Author(s):  
Yiguang Jin ◽  
Yanju Lian ◽  
Lina Du ◽  
Shuangmiao Wang ◽  
Chang Su ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
In Vivo Studies ◽  
Self Assembled

scholarly journals Anti-GD2 IgA kills tumors by neutrophils without antibody-associated pain in the preclinical treatment of high-risk neuroblastoma

2021 ◽  
Vol 9 (10) ◽  
pp. e003163
Author(s):  
Mitchell Evers ◽  
Marjolein Stip ◽  
Kaylee Keller ◽  
Hanneke Willemen ◽  
Maaike Nederend ◽  
...  
Keyword(s):  
High Risk ◽  
Sensory Neurons ◽  
Complement System ◽  
Severe Pain ◽  
Neuroblastoma Cells ◽  
Antibody Therapy ◽  
Preclinical Treatment ◽  
The Complement System

BackgroundThe addition of monoclonal antibody therapy against GD2 to the treatment of high-risk neuroblastoma led to improved responses in patients. Nevertheless, administration of GD2 antibodies against neuroblastoma is associated with therapy-limiting neuropathic pain. This severe pain is evoked at least partially through complement activation on GD2-expressing sensory neurons.MethodsTo reduce pain while maintaining antitumor activity, we have reformatted the approved GD2 antibody ch14.18 into the IgA1 isotype. This novel reformatted IgA is unable to activate the complement system but efficiently activates leukocytes through the FcαRI (CD89).ResultsIgA GD2 did not activate the complement system in vitro nor induced pain in mice. Importantly, neutrophil-mediated killing of neuroblastoma cells is enhanced with IgA in comparison to IgG, resulting in efficient tumoricidal capacity of the antibody in vitro and in vivo.ConclusionsOur results indicate that employing IgA GD2 as a novel isotype has two major benefits: it halts antibody-induced excruciating pain and improves neutrophil-mediated lysis of neuroblastoma. Thus, we postulate that patients with high-risk neuroblastoma would strongly benefit from IgA GD2 therapy.

scholarly journals Evaluation of Quinacrine Treatment for Prion Diseases

2003 ◽  
Vol 77 (15) ◽  
pp. 8462-8469 ◽  
Author(s):  
A. Barret ◽  
F. Tagliavini ◽  
G. Forloni ◽  
C. Bate ◽  
M. Salmona ◽  
...  
Keyword(s):  
Prion Protein ◽  
De Novo ◽  
Neuroblastoma Cells ◽  
Animal Origin ◽  
Detectable Effect ◽  
Spongiform Encephalopathy ◽  
Protease Resistance ◽  
New Variant

ABSTRACT Based on in vitro observations in scrapie-infected neuroblastoma cells, quinacrine has recently been proposed as a treatment for Creutzfeldt-Jakob disease (CJD), including a new variant CJD which is linked to contamination of food by the bovine spongiform encephalopathy (BSE) agent. The present study investigated possible mechanisms of action of quinacrine on prions. The ability of quinacrine to interact with and to reduce the protease resistance of PrP peptide aggregates and PrPres of human and animal origin were analyzed, together with its ability to inhibit the in vitro conversion of the normal prion protein (PrPc) to the abnormal form (PrPres). Furthermore, the efficiencies of quinacrine and chlorpromazine, another tricyclic compound, were examined in different in vitro models and in an experimental murine model of BSE. Quinacrine efficiently hampered de novo generation of fibrillogenic prion protein and PrPres accumulation in ScN2a cells. However, it was unable to affect the protease resistance of preexisting PrP fibrils and PrPres from brain homogenates, and a “curing” effect was obtained in ScGT1 cells only after lengthy treatment. In vivo, no detectable effect was observed in the animal model used, consistent with other recent studies and preliminary observations in humans. Despite its ability to cross the blood-brain barrier, the use of quinacrine for the treatment of CJD is questionable, at least as a monotherapy. The multistep experimental approach employed here could be used to test new therapeutic regimes before their use in human trials.

Adrenomedullin: angiogenesis and gene therapy

2005 ◽  
Vol 288 (6) ◽  
pp. R1432-R1437 ◽  
Author(s):  
Noritoshi Nagaya ◽  
Hidezo Mori ◽  
Shinsuke Murakami ◽  
Kenji Kangawa ◽  
Soichiro Kitamura
Keyword(s):  
Gene Transfer ◽  
Cell Biology ◽  
Therapeutic Potential ◽  
Lattice Structure ◽  
Rabbit Model ◽  
Mitogen Activated Protein Kinase ◽  
Tissue Ischemia ◽  
Hypoxic Conditions

Adrenomedullin (AM) is a potent, long-lasting vasodilator peptide that was originally isolated from human pheochromocytoma. AM signaling is of particular significance in endothelial cell biology since the peptide protects cells from apoptosis, promotes angiogenesis, and affects vascular tone and permeability. The angiogenic effect of AM is mediated by activation of Akt, mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2, and focal adhesion kinase in endothelial cells. Both AM and its receptor, calcitonin receptor-like receptor, are upregulated through a hypoxia-inducible factor-1-dependent pathway under hypoxic conditions. Thus AM signaling plays an important role in the regulation of angiogenesis in hypoxic conditions. Recently, we have developed a nonviral vector, gelatin. Positively charged gelatin holds negatively charged plasmid DNA in its lattice structure. DNA-gelatin complexes can delay gene degradation, leading to efficient gene transfer. Administration of AM DNA-gelatin complexes induces potent angiogenic effects in a rabbit model of hindlimb ischemia. Thus gelatin-mediated AM gene transfer may be a new therapeutic strategy for the treatment of tissue ischemia. Endothelial progenitor cells (EPCs) play an important role in endothelial regeneration. Interestingly, EPCs phagocytose ionically linked DNA-gelatin complexes in coculture, which allows nonviral gene transfer into EPCs. AM gene transfer into EPCs inhibits cell apoptosis and induces proliferation and migration, suggesting that AM gene transfer strengthens the therapeutic potential of EPCs. Intravenous administration of AM gene-modified EPCs regenerate pulmonary endothelium, resulting in improvement of pulmonary hypertension. These results suggest that in vivo and in vitro transfer of AM gene using gelatin may be applicable for intractable cardiovascular disease.

Ability to organize microtubules in taxol-treated mitotic PtK2 cells goes with the SPN antigen and not with the centrosome

1992 ◽  
Vol 102 (1) ◽  
pp. 91-102 ◽  
Author(s):  
M. Kallajoki ◽  
K. Weber ◽  
M. Osborn
Keyword(s):  
Plasma Membrane ◽  
Hela Cells ◽  
Nuclear Matrix ◽  
Essential Role ◽  
Soluble Form ◽  
Microtubule Nucleation ◽  
Brain Microtubules ◽  
Mitotic Cells

The SPN antigen plays an essential role in mitosis, since microinjection of antibodies causes mitotic arrest. Here we show, by examination of the relative locations of SPN antigen, the centrosomal 5051 antigen and tubulin in normal mitotic, and in taxol-treated mitotic cells, that the SPN antigen is involved in organizing the microtubules of the spindle. The 210 kDa protein defined as SPN antigen relocates from the nuclear matrix to the centrosome at prophase, remains associated with the poles at metaphase and anaphase, and dissociates from the centrosomes in telophase. In taxol-treated mitotic cells, SPN staining shows a striking redistribution while 5051 antigen remains associated with centrosomes. SPN antigen is seen at the plasma membrane end of the rearranged microtubules. SPN antigen is always at the center of the multiple microtubule asters (5 to 20 per cell) induced by taxol, whereas 5051 again remains associated with the centrosomal complex (1 to 2 foci per cell). Microtubule nucleation is associated with the SPN antigen rather than with the 5051 antigen. Microinjection of SPN-3 antibody into taxol-treated mitotic PtK2 cells causes disruption of the asters as judged by tubulin staining of the same cells. Finally, SPN antigen extracted in soluble form from synchronized mitotic HeLa cells binds to, and sediments with, pig brain microtubules stabilized by taxol. This association of SPN antigen with microtubules is partially dissociated by 0.5 M NaCl but not by 5 mM ATP. Thus SPN antigen binds to microtubules in vitro and seems to act as a microtubular minus-end organizer in mitotic cells in vivo.

scholarly journals Characterization of Anchorless Human PrP With Q227X Stop Mutation Linked to Gerstmann-Sträussler-Scheinker Syndrome In Vivo and In Vitro

2020 ◽  
Vol 58 (1) ◽  
pp. 21-33
Author(s):  
Pingping Shen ◽  
Johnny Dang ◽  
Zerui Wang ◽  
Weiguanliu Zhang ◽  
Jue Yuan ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Neuroblastoma Cells ◽  
Cellular Prion Protein ◽  
Wild Type ◽  
Gpi Anchor ◽  
Two Dimensional Gel Electrophoresis ◽  
Molecular Weights ◽  
Prion Propagation

AbstractAlteration in cellular prion protein (PrPC) localization on the cell surface through mediation of the glycosylphosphatidylinositol (GPI) anchor has been reported to dramatically affect the formation and infectivity of its pathological isoform (PrPSc). A patient with Gerstmann-Sträussler-Scheinker (GSS) syndrome was previously found to have a nonsense heterozygous PrP-Q227X mutation resulting in an anchorless PrP. However, the allelic origin of this anchorless PrPSc and cellular trafficking of PrPQ227X remain to be determined. Here, we show that PrPSc in the brain of this GSS patient is mainly composed of the mutant but not wild-type PrP (PrPWt), suggesting pathological PrPQ227X is incapable of recruiting PrPWt in vivo. This mutant anchorless protein, however, is able to recruit PrPWt from humanized transgenic mouse brain but not from autopsied human brain homogenates to produce a protease-resistant PrPSc-like form in vitro by protein misfolding cyclic amplification (PMCA). To further investigate the characteristics of this mutation, constructs expressing human PrPQ227X or PrPWt were transfected into neuroblastoma cells (M17). Fractionation of the M17 cells demonstrated that most PrPWt is recovered in the cell lysate fraction, while most of the mutant PrPQ227X is recovered in the medium fraction, consistent with the results obtained by immunofluorescence microscopy. Two-dimensional gel-electrophoresis and Western blotting showed that cellular PrPQ227X spots clustered at molecular weights of 22–25 kDa with an isoelectric point (pI) of 3.5–5.5, whereas protein spots from the medium are at 18–26 kDa with a pI of 7–10. Our findings suggest that the role of GPI anchor in prion propagation between the anchorless mutant PrP and wild-type PrP relies on the cellular distribution of the protein.

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