piperidines has been researched along with Neuroblastoma* in 95 studies
1 review(s) available for piperidines and Neuroblastoma
1 trial(s) available for piperidines and Neuroblastoma
94 other study(ies) available for piperidines and Neuroblastoma
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Novel S1R agonists counteracting NMDA excitotoxicity and oxidative stress: A step forward in the discovery of neuroprotective agents.
Sigma-1 receptor (S1R) has been considered a promising therapeutic target for several neurodegenerative diseases and S1R agonists have shown neuroprotective activity against glutamate excitotoxicity and oxidative stress. Starting from a previously identified low nanomolar S1R agonist, in this work we prepared and tested novel benzylpiperidine/benzylpiperazine-based compounds designed by applying a ring opening strategy. Among them, 4-benzyl-1-(2-phenoxyethyl)piperidine 6b (S1R Ki = 0.93 nM) and 4-benzyl-1-(3-phenoxypropyl)piperidine 8b (S1R Ki = 1.1 nM) emerged as high affinity S1R ligands and showed selectivity over S2R and N-methyl-d-aspartate receptor (NMDAR). Candidate compounds behaved as potent S1R agonists being able to enhance the neurite outgrowth induced by nerve growth factor (NGF) in PC12 cell lines. In SH-SY5Y neuroblastoma cell lines they exhibited a neuroprotective effect against rotenone- and NMDA-mediated toxic insults. The neuroprotective activity of 6b and 8b was reverted by co-treatment with an S1R antagonist, PB212. Compounds 6b and 8b were tested for cytotoxicity in-vitro against three human cancer cell lines (A549, LoVo and Panc-1) and in-vivo zebrafish model, resulting in a good efficacy/safety profile, comparable or superior to the reference drug memantine. Overall, these results encourage further preclinical investigations of 6b and 8b on in-vivo models of neurodegenerative diseases. Topics: Animals; Humans; N-Methylaspartate; Neuroblastoma; Neurodegenerative Diseases; Neuroprotective Agents; Oxidative Stress; Piperidines; Receptors, sigma; Zebrafish | 2023 |
Biological response and cell death signaling pathways modulated by tetrahydroisoquinoline-based aldoximes in human cells.
The uncharged 3-hydroxy-2-pyridine aldoximes with protonatable tertiary amines are studied as antidotes in toxic organophosphates (OP) poisoning. Due to some of their specific structural features, we hypothesize that these compounds could exert diverse biological activity beyond their main scope of application. To examine this further, we performed an extensive cell-based assessment to determine their effects on human cells (SH-SY5Y, HEK293, HepG2, HK-2, myoblasts and myotubes) and possible mechanism of action. As our results indicated, aldoxime having a piperidine moiety did not induce significant toxicity up to 300 µM within 24 h, while those with a tetrahydroisoquinoline moiety, in the same concentration range, showed time-dependent effects and stimulated mitochondria-mediated activation of the intrinsic apoptosis pathway through ERK1/2 and p38-MAPK signaling and subsequent activation of initiator caspase 9 and executive caspase 3 accompanied with DNA damage as observed already after 4 h exposure. Mitochondria and fatty acid metabolism were also likely targets of 3-hydroxy-2-pyridine aldoximes with tetrahydroisoquinoline moiety, due to increased phosphorylation of acetyl-CoA carboxylase. In silico analysis predicted kinases as their most probable target class, while pharmacophores modeling additionally predicted the inhibition of a cytochrome P450cam. Overall, if the absence of significant toxicity for piperidine bearing aldoxime highlights the potential of its further studies in medical counter-measures, the observed biological activity of aldoximes with tetrahydroisoquinoline moiety could be indicative for future design of compounds either in a negative context in OP antidotes design, or in a positive one for design of compounds for the treatment of other phenomena like cell proliferating malignancies. Topics: Antidotes; Apoptosis; HEK293 Cells; Humans; Neuroblastoma; Organophosphates; Oximes; Piperidines; Pyridines; Signal Transduction; Tetrahydroisoquinolines | 2023 |
Synthesis and biological evaluation of 4-hydroxy-methylpiperidinyl-N-benzyl-acylarylhydrazone hybrids designed as novel multifunctional drug candidates for Alzheimer's disease.
The search for new drug candidates against Alzheimer's disease (AD) remains a complex challenge for medicinal chemists due to its multifactorial pathogenesis and incompletely understood physiopathology. In this context, we have explored the molecular hybridization of pharmacophore structural fragments from known bioactive molecules, aiming to obtain a novel molecular architecture in new chemical entities capable of concomitantly interacting with multiple targets in a so-called multi-target directed ligands (MTDLs) approach. This work describes the synthesis of 4-hydroxymethyl)piperidine-N-benzyl-acyl-hydrazone derivatives 5a-l, designed as novel MTDLs, showing improved multifunctional properties compared to the previously reported parent series of N-benzyl-(3-hydroxy)piperidine-acyl-hydrazone derivatives 4. The new improved derivatives were studied in silico, regarding their mode of interaction with AChE enzyme, and in vitro, for evaluation of their effects on the selective inhibition of cholinesterases, cellular antioxidant, and neuroprotective activities as their cytotoxicity in human neuroblastoma (SH-SY5Y) cells. Overall, compound PQM-181 (5 k) showed the best balanced selective and non-competitive inhibition of AChE (IC Topics: Acetylcholinesterase; Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Cholinesterase Inhibitors; Drug Design; Humans; Hydrazones; Ligands; Molecular Structure; Neuroblastoma; Neuroprotective Agents; Piperidines; Structure-Activity Relationship | 2022 |
BioID-Screening Identifies PEAK1 and SHP2 as Components of the ALK Proximitome in Neuroblastoma Cells.
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that is mutated in approximately 10% of pediatric neuroblastoma (NB). To shed light on ALK-driven signaling processes, we employed BioID-based in vivo proximity labeling to identify molecules that interact intracellularly with ALK. NB-derived SK-N-AS and SK-N-BE(2) cells expressing inducible ALK-BirA* fusion proteins were generated and stimulated with ALKAL ligands in the presence and absence of the ALK tyrosine kinase inhibitor (TKI) lorlatinib. LC/MS-MS analysis identified multiple proteins, including PEAK1 and SHP2, which were validated as ALK interactors in NB cells. Further analysis of the ALK-SHP2 interaction confirmed that the ALK-SHP2 interaction as well as SHP2-Y542 phosphorylation was dependent on ALK activation. Use of the SHP2 inhibitors, SHP099 and RMC-4550, resulted in inhibition of cell growth in ALK-driven NB cells. In addition, we noted a strong synergistic effect of combined ALK and SHP2 inhibition that was specific to ALK-driven NB cells, suggesting a potential therapeutic option for ALK-driven NB. Topics: Aminopyridines; Anaplastic Lymphoma Kinase; Animals; Cell Line, Tumor; Chromatography, Liquid; Drug Synergism; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Lactams; Neuroblastoma; PC12 Cells; Phosphorylation; Piperidines; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Protein-Tyrosine Kinases; Proteomics; Pyrazoles; Pyrimidines; Rats; Tandem Mass Spectrometry | 2021 |
Survival for high-risk neuroblastoma remains poor and treatment for relapsed disease rarely leads to long-term cures. Large sequencing studies of neuroblastoma tumors from diagnosis have not identified common targetable driver mutations other than the 10% of tumors that harbor mutations in the anaplastic lymphoma kinase ( Topics: Aminopyridines; Animals; Antineoplastic Agents; Cell Line, Tumor; Drug Resistance, Neoplasm; Drug Synergism; Genes, ras; Heterografts; Humans; Indoles; Male; MAP Kinase Signaling System; Mice, Inbred NOD; Mice, SCID; Mitogen-Activated Protein Kinase Kinases; Mutation; Neoplasm Recurrence, Local; Neuroblastoma; Piperidines; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Pyridones; Pyrimidines; Pyrimidinones; Pyrroles; Triazoles; Vemurafenib | 2020 |
Repaglinide Silences the FOXO3/Lumican Axis and Represses the Associated Metastatic Potential of Neuronal Cancer Cells.
The transcription factor FOXO3 is associated with poor outcome in high-stage neuroblastoma (NB), as it facilitates chemoprotection and tumor angiogenesis. In other tumor entities, FOXO3 stimulates metastasis formation, one of the biggest challenges in the treatment of aggressive NB. However, the impact of FOXO3 on the metastatic potential of neuronal tumor cells remains largely unknown. In the present study, we uncover the small leucine-rich proteoglycan family member lumican (LUM) as a FOXO3-regulated gene that stimulates cellular migration in NB. By a drug-library screen we identified the small molecular weight compound repaglinide (RPG) as a putative FOXO3 inhibitor. Here, we verify that RPG binds to the FOXO3-DNA-binding-domain (DBD) and thereby silences the transcriptional activity of FOXO3. Consistent with the concept that the FOXO3/LUM axis enhances the migratory capacity of aggressive NB cells, we demonstrate that stable knockdown of LUM abrogates the FOXO3-mediated increase in cellular migration. Importantly, FOXO3 inhibition by RPG represses the binding of FOXO3 to the LUM promoter, inhibits FOXO3-mediated LUM RNA and protein expression, and efficiently abrogates FOXO3-triggered cellular "wound healing" as well as spheroid-based 3D-migration. Thus, silencing the FOXO3/LUM axis by the FDA-approved compound RPG represents a promising strategy for novel therapeutic interventions in NB and other FOXO3-dependent tumors. Topics: Carbamates; Cell Line, Tumor; Cell Movement; Down-Regulation; Forkhead Box Protein O3; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Lumican; Neuroblastoma; Piperidines; Promoter Regions, Genetic; Protein Binding | 2019 |
Dual-Functioning Scaffolds for the Treatment of Spinal Cord Injury: Alginate Nanofibers Loaded with the Sigma 1 Receptor (S1R) Agonist RC-33 in Chitosan Films.
The present work proposed a novel therapeutic platform with both neuroprotective and neuroregenerative potential to be used in the treatment of spinal cord injury (SCI). A dual-functioning scaffold for the delivery of the neuroprotective S1R agonist, RC-33, to be locally implanted at the site of SCI, was developed. RC-33-loaded fibers, containing alginate (ALG) and a mixture of two different grades of poly(ethylene oxide) (PEO), were prepared by electrospinning. After ionotropic cross-linking, fibers were incorporated in chitosan (CS) films to obtain a drug delivery system more flexible, easier to handle, and characterized by a controlled degradation rate. Dialysis equilibrium studies demonstrated that ALG was able to form an interaction product with the cationic RC-33 and to control RC-33 release in the physiological medium. Fibers loaded with RC-33 at the concentration corresponding to 10% of ALG maximum binding capacity were incorporated in films based on CS at two different molecular weights-low (CSL) and medium (CSM)-solubilized in acetic (AA) or glutamic (GA) acid. CSL- based scaffolds were subjected to a degradation test in order to investigate if the different CSL salification could affect the film behavior when in contact with media that mimic SCI environment. CSL AA exhibited a slower biodegradation and a good compatibility towards human neuroblastoma cell line. Topics: Alginates; Biphenyl Compounds; Cell Line, Tumor; Chitosan; Drug Carriers; Drug Delivery Systems; Humans; Molecular Weight; Nanofibers; Neuroblastoma; Neuroprotective Agents; Piperidines; Polyethylene Glycols; Receptors, sigma; Sigma-1 Receptor; Spinal Cord Injuries | 2019 |
Combined Inhibition of ALK and HDAC Induces Synergistic Cytotoxicity in Neuroblastoma Cell Lines.
Neuroblastoma (NB) is the most common extracranial solid tumor in childhood; treatments with greater effectiveness are required for NB, especially in advanced cases. This study aimed at evaluating the combined effect of anaplastic lymphoma kinase (ALK) inhibitor alectinib and histone deacetylase inhibitor vorinostat on NB cell lines harboring wild-type or mutated ALK.. Cytotoxicity was examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide assay. Protein expression was analyzed using western blotting.. Combination treatment with alectinib and vorinostat had a synergistic effect on growth inhibition of the NB cell line with ALK R1275Q mutation. Cleavage of caspase-3 and poly-(ADP-ribose) polymerase increased, indicating enhanced caspase-dependent apoptosis. In addition, this combination reduced the protein levels of MYCN proto-oncogene and nuclear factor kappa B, both of which are important for NB tumorigenesis and progression.. Combined treatment with alectinib and vorinostat might be a novel therapeutic option for NB harboring the ALK R1275Q mutation. Topics: Anaplastic Lymphoma Kinase; Carbazoles; Cell Line, Tumor; Cell Survival; Drug Synergism; Histone Deacetylase Inhibitors; Humans; Mutation; N-Myc Proto-Oncogene Protein; Neuroblastoma; NF-kappa B; Piperidines; Protein Kinase Inhibitors; Proto-Oncogene Mas; Vorinostat | 2019 |
Heterogeneous distribution of alectinib in neuroblastoma xenografts revealed by matrix-assisted laser desorption ionization mass spectrometry imaging: a pilot study.
The penetration of the anaplastic lymphoma kinase (ALK) inhibitor alectinib in neuroblastomas and the relationship between alectinib and ALK expression are unknown. The aim of this study was to perform a quantitative investigation of the inter- and intra-tumoural distribution of alectinib in different neuroblastoma xenograft models using matrix-assisted laser desorption ionization MS imaging (MALDI-MSI).. The distribution of alectinib in NB1 (ALK amplification) and SK-N-FI (ALK wild-type) xenograft tissues was analysed using MALDI-MSI. The abundance of alectinib in tumours and intra-tumoural areas was quantified using ion signal intensities from MALDI-MSI after normalization by correlation with LC-MS/MS.. The distribution of alectinib was heterogeneous in neuroblastomas. The penetration of alectinib was not significantly different between ALK amplification and ALK wide-type tissues using both LC-MS/MS concentrations and MSI intensities. Normalization with an internal standard increased the quantitative property of MSI by adjusting for the ion suppression effect. The distribution of alectinib in different intra-tumoural areas can alternatively be quantified from MS images by correlation with LC-MS/MS.. The penetration of alectinib into tumour tissues may not be homogenous or influenced by ALK expression in the early period after single-dose administration. MALDI-MSI may prove to be a valuable pharmaceutical method for elucidating the mechanism of action of drugs by clarifying their microscopic distribution in heterogeneous tissues. Topics: Animals; Carbazoles; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neuroblastoma; Pilot Projects; Piperidines; Protein Kinase Inhibitors; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Xenograft Model Antitumor Assays | 2018 |
Vandetanib inhibits cisplatin‑resistant neuroblastoma tumor growth and invasion.
Resistance is the major cause of cisplatin treatment failure in neuroblastoma (NB). Vandetanib is widely used in the treatment of several cancers. In the present study, we aimed to determine the potential of vandetanib in cisplatin‑resistant NB therapy. Immunohistochemistry (IHC) staining was employed to detect p‑RET and CXCR4 expression in cisplatin‑resistant or ‑sensitive NB tissues from patients. Vandetanib was added to treat selected cisplatin‑resistant SH‑SY5Y cells (SH‑SY5Y‑R); this was followed by CCK8 assay, colony formation assay, and invasion assay. Furthermore, the effect of vandetanib on subcutaneous tumor growth was investigated in mice. Our results demonstrated greater expression of p‑RET and CXCR4 in cisplatin‑resistant neuroblastomas (NBs). Vandetanib significantly inhibited SH‑SY5Y‑R cell proliferation, colony formation, and invasion, while downregulating p‑RET and CXCR4 expression. Furthermore, vandetanib was as effective as high‑dose cisplatin in impairing cisplatin‑resistant NB subcutaneous tumor growth. Notably, vandetanib caused less severe liver toxicity in mice compared with high‑dose cisplatin. In summary, this study identified Vandetanib as a potential drug for cisplatin‑resistant NB treatment. Topics: Animals; Cell Line, Tumor; Cell Proliferation; Cisplatin; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Neoplasm Invasiveness; Neuroblastoma; Piperidines; Proto-Oncogene Proteins c-ret; Quinazolines; Receptors, CXCR4; Signal Transduction | 2018 |
Good clinical response to alectinib, a second generation ALK inhibitor, in refractory neuroblastoma.
Topics: Adolescent; Antineoplastic Agents; Carbazoles; Drug Resistance, Neoplasm; Female; Humans; Neoplasm Recurrence, Local; Neuroblastoma; Piperidines; Protein Kinase Inhibitors | 2018 |
Protective Effects of Donepezil Against Alcohol-Induced Toxicity in Cell Culture: Role of Caspase-3.
Ethanol (EtOH) is one of the most frequently abused drugs with heavy health, economic, and societal burdens. Although moderate to low EtOH may have some neuroprotective effects, heavy EtOH consumption associated with high blood alcohol level (BAL) can be quite detrimental. The brain is particularly vulnerable to the damaging effects of high BAL, leading to neuronal loss, cognitive, and behavioral deficits. Although the exact causes of these detriments are not fully elucidated, it is believed that damage to the cholinergic system is at least partially responsible for the cognitive impairment. Thus, high BAL may result in selective apoptotic damage to the cholinergic neurons. Donepezil (DON), a centrally acting, reversible and non-competitive acetylcholinesterase (AChE) inhibitor, approved for use in Alzheimer's disease (AD), may also attenuate EtOH-induced cognitive impairment. Cognitive effects of DON might be due to an anti-apoptotic activity as some AChE inhibitors have been shown to have this property. The aim of this study was to determine whether DON might protect against EtOH-induced toxicity and whether such protection might be apoptotically mediated. We exposed the human neuroblastoma-derived, SH-SY5Y cells to a relatively high concentration of EtOH (500 mM) for 24 h and evaluated the effects of two concentrations of DON (0.1 and 1.0 μM) on alcohol-induced toxicity and caspase-3, an apoptotic marker. We found a dose-dependent protection of DON against EtOH-induced toxicity as well as dose-dependent attenuation of EtOH-induced increases in caspase-3 levels. Thus, DON may inhibit apoptosis as well as alcohol-induced toxicity. Topics: Caspase 3; Cell Line, Tumor; Central Nervous System Depressants; Donepezil; Dose-Response Relationship, Drug; Drug Synergism; Ethanol; Humans; Indans; Neuroblastoma; Neuroprotective Agents; Piperidines | 2018 |
Bruton's tyrosine kinase potentiates ALK signaling and serves as a potential therapeutic target of neuroblastoma.
Aberrant activation of anaplastic lymphoma kinase (ALK) can cause sporadic and familial neuroblastoma. Using a proteomics approach, we identified Bruton's tyrosine kinase (BTK) as a novel ALK interaction partner, and the physical interaction was confirmed by co-immunoprecipitation. BTK is expressed in neuroblastoma cell lines and tumor tissues. Its high expression correlates with poor relapse-free survival probability of neuroblastoma patients. Mechanistically, we demonstrated that BTK potentiates ALK-mediated signaling in neuroblastoma, and increases ALK stability by reducing ALK ubiquitination. Both ALK Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Anaplastic Lymphoma Kinase; Animals; Antineoplastic Agents; Crizotinib; Humans; Mice; Mice, Nude; Neuroblastoma; Piperidines; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Signal Transduction; Xenograft Model Antitumor Assays | 2018 |
The second-generation ALK inhibitor alectinib effectively induces apoptosis in human neuroblastoma cells and inhibits tumor growth in a TH-MYCN transgenic neuroblastoma mouse model.
Activating germline mutations of anaplastic lymphoma kinase (ALK) occur in most cases of hereditary neuroblastoma (NB) and the constitutively active kinase activity of ALK promotes cell proliferation and survival in NB. Therefore, ALK kinase is a potential therapeutic target for NB. In this study, we show that the novel ALK inhibitor alectinib effectively suppressed cell proliferation and induces apoptosis in NB cell lines with either wild-type ALK or mutated ALK (F1174L and D1091N) by blocking ALK-mediated PI3K/Akt/mTOR signaling. In addition, alectinib enhanced doxorubicin-induced cytotoxicity and apoptosis in NB cells. Furthermore, alectinib induced apoptosis in an orthotopic xenograft NB mouse model. Also, in the TH-MYCN transgenic mouse model, alectinib resulted in decreased tumor growth and prolonged survival time. These results indicate that alectinib may be a promising therapeutic agent for the treatment of NB. Topics: Anaplastic Lymphoma Kinase; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carbazoles; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Doxorubicin; Female; Genetic Predisposition to Disease; Humans; Inhibitory Concentration 50; Mice, Nude; Mice, Transgenic; Mutation; N-Myc Proto-Oncogene Protein; Neuroblastoma; Phenotype; Phosphatidylinositol 3-Kinase; Piperidines; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Receptor Protein-Tyrosine Kinases; Signal Transduction; Time Factors; TOR Serine-Threonine Kinases; Tumor Burden; Xenograft Model Antitumor Assays | 2017 |
Acetamide Derivatives of Chromen-2-ones as Potent Cholinesterase Inhibitors.
Alzheimer's disease (AD), a neurodegenerative disorder, is a serious medical issue worldwide with drastic social consequences. Inhibition of cholinesterase is one of the rational and effective approaches to retard the symptoms of AD and, hence, consistent efforts are being made to develop efficient anti-cholinesterase agents. In pursuit of this, a series of 19 acetamide derivatives of chromen-2-ones were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential. All the synthesized compounds exhibited significant anti-AChE and anti-BChE activity, with IC Topics: Acetylcholinesterase; Alzheimer Disease; Animals; Blood-Brain Barrier; Butyrylcholinesterase; Cholinesterase Inhibitors; Chromones; Donepezil; Electrophorus; Erythrocytes; Hemolysis; Humans; Indans; Inhibitory Concentration 50; Neuroblastoma; Piperidines | 2017 |
N-Benzylpiperidine Derivatives as α7 Nicotinic Receptor Antagonists.
A series of multitarget directed propargylamines, as well as other differently susbstituted piperidines have been screened as potential modulators of neuronal nicotinic acetylcholine receptors (nAChRs). Most of them showed antagonist actions on α7 nAChRs. Especially, compounds 13, 26, and 38 displayed submicromolar IC50 values on homomeric α7 nAChRs, whereas they were less effective on heteromeric α3β4 and α4β2 nAChRs (up to 20-fold higher IC50 values in the case of 13). Antagonism was concentration dependent and noncompetitive, suggesting that these compounds behave as negative allosteric modulators of nAChRs. Upon the study of a series of less complex derivatives, the N-benzylpiperidine motif, common to these compounds, was found to be the main pharmacophoric group. Thus, 2-(1-benzylpiperidin-4-yl)-ethylamine (48) showed an inhibitory potency comparable to the one of the previous compounds and also a clear preference for α7 nAChRs. In a neuroblastoma cell line, representative compounds 13 and 48 also inhibited, in a concentration-dependent manner, cytosolic Ca(2+) signals mediated by nAChRs. Finally, compounds 38 and 13 inhibited 5-HT3A serotonin receptors whereas they had no effect on α1 glycine receptors. Given the multifactorial nature of many pathologies in which nAChRs are involved, these piperidine antagonists could have a therapeutic potential in cases where cholinergic activity has to be negatively modulated. Topics: Acetylcholine; alpha7 Nicotinic Acetylcholine Receptor; Animals; Calcium; Cell Line, Tumor; Dose-Response Relationship, Drug; Inhibitory Concentration 50; Isoxazoles; Membrane Potentials; Microinjections; Neuroblastoma; Nicotinic Agonists; Nicotinic Antagonists; Oocytes; Patch-Clamp Techniques; Phenylurea Compounds; Piperidines; Receptors, Nicotinic; Receptors, Serotonin, 5-HT3; Serotonin; Xenopus laevis | 2016 |
Cyclin-Dependent Kinase Inhibitor AT7519 as a Potential Drug for MYCN-Dependent Neuroblastoma.
MYCN-dependent neuroblastomas have low cure rates with current multimodal treatment regimens and novel therapeutic drugs are therefore urgently needed. In previous preclinical studies, we have shown that targeted inhibition of cyclin-dependent kinase 2 (CDK2) resulted in specific killing of MYCN-amplified neuroblastoma cells. This study describes the in vivo preclinical evaluation of the CDK inhibitor AT7519.. Preclinical drug testing was performed using a panel of MYCN-amplified and MYCN single copy neuroblastoma cell lines and different MYCN-dependent mouse models of neuroblastoma.. AT7519 killed MYCN-amplified neuroblastoma cell lines more potently than MYCN single copy cell lines with a median LC50 value of 1.7 compared to 8.1 μmol/L (P = 0.0053) and a significantly stronger induction of apoptosis. Preclinical studies in female NMRI homozygous (nu/nu) mice with neuroblastoma patient-derived MYCN-amplified AMC711T xenografts revealed dose-dependent growth inhibition, which correlated with intratumoral AT7519 levels. CDK2 target inhibition by AT7519 was confirmed by significant reductions in levels of phosphorylated retinoblastoma (p-Rb) and nucleophosmin (p-NPM). AT7519 treatment of Th-MYCN transgenic mice resulted in improved survival and clinically significant tumor regression (average tumor size reduction of 86% at day 7 after treatment initiation). The improved efficacy of AT7519 observed in Th-MYCN mice correlated with higher tumor exposure to the drug.. This study strongly suggests that AT7519 is a promising drug for the treatment of high-risk neuroblastoma patients with MYCN amplification. Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase 2; Female; Gene Expression Regulation, Neoplastic; Humans; Mice; N-Myc Proto-Oncogene Protein; Neuroblastoma; Nuclear Proteins; Oncogene Proteins; Piperidines; Protein Kinase Inhibitors; Pyrazoles; Xenograft Model Antitumor Assays | 2015 |
Targeted inhibition of MEK1 by cobimetinib leads to differentiation and apoptosis in neuroblastoma cells.
Neuroblastoma (NB) is one of the most common childhood malignancies. Currently, high risk NB carries a poor outcome and significant treatment related toxicities and, thus has been a focus for new therapeutics research in pediatric oncology. In this study, we evaluated the effects of the MEK inhibitor cobimetinib, as a single agent and in combinations, on the growth, survival and differentiation properties against a molecularly representative panel of NB cell lines.. In vitro anti-proliferative activity of cobimetinib alone or in combination was investigated by cell viability assays and its target modulatory activity was evaluated using phospho-kinases antibody arrays and western blot analysis. To determine the effect of combination with cis-RA on differentiation and resulting enhanced cellular cytotoxicity, the expression of glial fibrillary acidic protein (GFAP) and microtubule-associated protein 2 (MAP2) expression levels were examined by immuno-fluorescence.. Our findings show that cobimetinib alone induced a concentration-dependent loss of cell viability in all NB cell lines. In addition, cobimetinib showed feedback activation of MEK1/2, and the dephosphorylation of extracellular signal-regulated kinases (ERK1/2) and c-RAF, providing information on the biological correlates of MEK inhibition in NB. Combined treatment with cis-RA, led to differentiation and enhanced sensitization of NB cells lines to cobimetinib.. Collectively, our results provide evidence that cobimetinib, in combination with cis-RA, represents a feasible option to develop novel treatment strategies for refractory NB. Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Azetidines; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cell Survival; Extracellular Signal-Regulated MAP Kinases; Glial Fibrillary Acidic Protein; Humans; Isotretinoin; MAP Kinase Kinase 1; MAP Kinase Signaling System; Microtubule-Associated Proteins; Neuroblastoma; Piperidines; Proto-Oncogene Proteins c-raf | 2015 |
Discovery of Inhibitors That Overcome the G1202R Anaplastic Lymphoma Kinase Resistance Mutation.
The treatment of patients with advanced non-small-cell lung cancer harboring chromosomal rearrangements of anaplastic lymphoma kinase (ALK) has been revolutionized by the development of crizotinib, a small-molecule inhibitor of ALK, ROS1, and MET. However, resistance to crizotinib inevitably develops through a variety of mechanisms, leading to relapse both systemically and in the central nervous system (CNS). This has motivated the development of "second-generation" ALK inhibitors, including alectinib and ceritinib, that overcome some of the mutations leading to resistance. However, most of the reported ALK inhibitors do not show inhibition of the G1202R mutant, which is one of the most common mutations. Herein, we report the development of a structural analogue of alectinib (JH-VIII-157-02) that is potent against the G1202R mutant as well as a variety of other frequently observed mutants. In addition, JH-VIII-157-02 is capable of penetrating the CNS of mice following oral dosing. Topics: Anaplastic Lymphoma Kinase; Animals; Carbazoles; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Drug Resistance, Neoplasm; Humans; Lung; Lung Neoplasms; Mice; Molecular Docking Simulation; Neuroblastoma; NIH 3T3 Cells; Piperidines; Point Mutation; Protein Kinase Inhibitors; Receptor Protein-Tyrosine Kinases | 2015 |
Liquid chromatography-tandem mass spectrometric assay for the cyclin-dependent kinase inhibitor AT7519 in mouse plasma.
A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for the cyclin-dependent kinase inhibitor AT7519 in mouse plasma was developed and validated. Plasma samples were pre-treated using protein precipitation with acetonitrile containing rucaparib as internal standard. After dilution with water, the extract was directly injected into the reversed-phase LC system. The eluate was transferred into the electrospray interface with positive ionization and the analyte was detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was validated in a 5-10,000ng/ml calibration range using double logarithmic calibration, 5ng/ml was the lower limit of quantification. Within day precisions (n=6) were 2.9-5.6%, between day (3 days; n=18) precisions 3.2-7.2%. Accuracies were between 95.9 and 99.0% for the whole calibration range. The drug was stable under all relevant analytical conditions. Finally, the assay was successfully used to determine plasma pharmacokinetics after intraperitoneal administration of AT7519 in mice with neuroblastoma xenografts. Topics: Animals; Calibration; Chromatography, Liquid; Cyclin-Dependent Kinases; Female; Indoles; Mice; Mice, Nude; Neoplasm Transplantation; Neuroblastoma; Piperidines; Protein Kinase Inhibitors; Pyrazoles; Reproducibility of Results; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry | 2014 |
Vandetanib-induced inhibition of neuroblastoma cell migration and invasion is associated with downregulation of the SDF-1/CXCR4 axis and matrix metalloproteinase 14.
Rearranged during transfection (RET) is widely expressed in neuroblastoma (NB) and partly contributes to high metastatic potential and survival of NB. The aim of the present study was to investigate whether vandetanib (a RET inhibitor) inhibits proliferation, migration and invasion of NB cells in vitro. The effects of vandetanib on the proliferation, apoptosis and cell cycle and on RET phosphorylation of SK-N-SH and SH-SY5Y cells were evaluated in vitro. The migration and invasion potential of vandetanib-treated NB cells were analyzed using Transwell cell migration and invasion assays, respectively. qPCR, western blotting and immunofluorescence were used to detect mRNA and protein levels in NB cells treated with vandetanib. Our data demonstrated that vandetanib inhibits the proliferation of SK-N-SH and SH-SY5Y cells and that this inhibition is mediated by the induction of G1 phase cell cycle arrest at lower concentrations and by apoptosis at higher concentrations. In the presence of vandetanib, the migration and invasion of two NB cell lines were markedly decreased compared with the control group (p<0.01). In addition, our data showed that the levels of C-X-C chemokine receptor type 4 (CXCR4) and matrix metalloproteinase 14 (MMP14) mRNA expression in NB cell lines treated with vandetanib were significantly lower than those in the cells that were treated with vehicle (p<0.01) and similar results were obtained for protein levels as determined by western blotting and immunofluorescence analysis. Vandetanib may inhibit the proliferation, migration and invasion of NB cells in vitro. The potential mechanisms for the inhibition of NB migration and invasion by vandetanib may partly be attributed to the ability of vandetanib to suppress the expression of CXCR4 and MMP14 in human NB cells. Topics: Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Movement; Chemokine CXCL12; Down-Regulation; Drug Screening Assays, Antitumor; G1 Phase Cell Cycle Checkpoints; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; Inhibitory Concentration 50; Matrix Metalloproteinase 14; Neoplasm Invasiveness; Neuroblastoma; Phosphorylation; Piperidines; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-ret; Quinazolines; Receptors, CXCR4 | 2014 |
Comprehensive DNA methylation analysis of human neuroblastoma cells treated with blonanserin.
Blonanserin is a second-generation antipsychotic drug for schizophrenia. The pharmacological actions of blonanserin are shown to be the antagonism of dopamine receptor 2 and serotonin receptors. However, its molecular mechanisms in brain cells have not been fully characterized. Accumulating evidence suggests that antipsychotic drugs and mood stabilizers show epigenetic effects on a wide range of genes in animal and cellular models. We performed genome-wide DNA methylation analysis targeting 479,814 CpG sites of cultured human neuroblastoma cells administered with blonanserin. We found that 3,057 CpG sites showed statistically significant changes in DNA methylation at two different doses of blonanserin (1.36 nM and 13.6 nM). These included hypermethylated CpG sites that were enriched in genes related to axonogenesis and cell morphogenesis involved in neuron differentiation. We also showed that the global effect on DNA methylome depends on the concentration of the drug. With a high dose of blonanserin, the overall methylation levels across all CpG sites significantly increased. These increases in DNA methylation were prominent in the CpG sites distant from promoter regions. We further examined DNA methylation changes in specific genes implicated for the actions of antipsychotic drugs, such as the dopamine receptor 2 (DRD2) gene and the serotonin receptor 2A (HTR2A) gene. We observed that CpG sites that were located within DRD2 and HTR2A genes were significantly hypermethylated by blonanserin. The DNA methylation changes induced by the treatment with blonanserin will be useful for understanding its pharmacological actions at the cellular level. Topics: Antipsychotic Agents; Cell Line, Tumor; CpG Islands; DNA Methylation; Dose-Response Relationship, Drug; Genome, Human; Humans; Neuroblastoma; Piperazines; Piperidines | 2014 |
Wnt signaling pathway, a potential target for Alzheimer's disease treatment, is activated by a novel multitarget compound ASS234.
Topics: Cell Line, Tumor; Enzyme Inhibitors; Gene Expression; Humans; Indoles; Neuroblastoma; Piperidines; PPAR alpha; Wnt Signaling Pathway | 2014 |
Augmenting anti-cancer natural products with a small molecule adjuvant.
Aquatic microbes produce diverse secondary metabolites with interesting biological activities. Cytotoxic metabolites have the potential to become lead compounds or drugs for cancer treatment. Many cytotoxic compounds, however, show undesirable toxicity at higher concentrations. Such undesirable activity may be reduced or eliminated by using lower doses of the cytotoxic compound in combination with another compound that modulates its activity. Here, we have examined the cytotoxicity of four microbial metabolites [ethyl N-(2-phenethyl) carbamate (NP-1), Euglenophycin, Anabaenopeptin, and Glycolipid 652] using three in vitro cell lines [human breast cancer cells (MCF-7), mouse neuroblastoma cells (N2a), and rat pituitary epithelial cells (GH4C1)]. The compounds showed variable cytotoxicity, with Euglenophycin displaying specificity for N2a cells. We have also examined the modulatory power of NP-1 on the cytotoxicity of the other three compounds and found that at a permissible concentration (125 µg/mL), NP-1 sensitized N2a and MCF-7 cells to Euglenophycin and Glycolipid 652 induced cytotoxicity. Topics: Adjuvants, Pharmaceutic; Animals; Antineoplastic Agents; Biological Products; Brain Neoplasms; Cell Line, Tumor; Glycolipids; Humans; Marine Toxins; MCF-7 Cells; Mice; Neuroblastoma; Peptides, Cyclic; Piperidines; Rats; Seawater; Thiazoles | 2014 |
Poly (ADP-Ribose) polymerase inhibitor MK-4827 together with radiation as a novel therapy for metastatic neuroblastoma.
To assess poly (ADP-ribose) polymerase (PARP) inhibitor MK-4827 together with radiation for the treatment of neuroblastoma.. Clonogenic survival assays were used to assess MK-4827, radiation and combination thereof in four neuroblastoma cell lines. In vivo efficacy was tested in a murine xenograft model of metastatic neuroblastoma. In vivo targeted inhibition and biological effects included measurement of cleaved caspase-3, γ-H2AX, and Ki 67 by immunohistochemistry (IHC) and poly-ADP-ribose by Enzyme-Linked Immunosorbent Assay.. Treatment of neuroblastoma cell lines reduced clonogenicity and resulted in additive effects with radiation. In vivo treatment with MK-4827 and radiation prolonged survival (p<0.01) compared to single modalities. In vivo superiority of MK-4827 plus radiation was further documented by significant elevations of cleaved caspase-3 and γ-H2AX in tumors from the combination group compared to single modality cohorts.. Combination of MK-4827 and radiation might provide effective therapy for children with high-risk neuroblastoma. Topics: Animals; Caspase 3; Cell Line, Tumor; Chemoradiotherapy; Enzyme Inhibitors; Female; Histones; Humans; Indazoles; Mice; Neoplasm Metastasis; Neuroblastoma; Piperidines; Poly(ADP-ribose) Polymerase Inhibitors; Radiation-Sensitizing Agents | 2013 |
Estradiol and testosterone regulate arginine-vasopressin expression in SH-SY5Y human female neuroblastoma cells through estrogen receptors-α and -β.
The expression of arginine-vasopressin (AVP) is regulated by estradiol and testosterone (T) in different neuronal populations by mechanisms that are not yet fully understood. Estrogen receptors (ERs) have been shown to participate in the regulation of AVP neurons by estradiol. In addition, there is evidence of the participation of ERβ in the regulation of AVP expression exerted by T via its metabolite 5α-dihydrotestosterone (5α-DHT) and its further conversion in the androgen metabolite and ERβ ligand 3β-diol. In this study we have explored the role of ERs in the regulation exerted by estradiol and T on AVP expression, using the human neuroblastoma cell line SH-SY5Y. Estradiol treatment increased AVP mRNA levels in SH-SY5Y cells in comparison with cells treated with vehicle. The stimulatory effect of estradiol on AVP expression was imitated by the ERα agonist 4,4',4',-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol and blocked by the ER antagonist, ICI 182,780, and the ERα antagonist 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1hpyrazoledihydrochloride. In contrast, the ERβ agonist 2,3-bis(4-hydroxyphenyl)-propionitrile reduced AVP expression, whereas the ERβ antagonist 4-[2-phenyl-5,7-bis(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-3-yl]phenol enhanced the action of estradiol on AVP expression. T increased AVP expression in SH-SY5Y cells by a mechanism that was dependent on aromatase but not on 5α-reductase activity. The T effect was not affected by blocking the androgen receptor, was not imitated by the T metabolite 5α-DHT, and was blocked by the ERα antagonist 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1hpyrazoledihydrochloride. In contrast, 5α-DHT had a similar effect as the ERβ agonists 2,3-bis(4-hydroxyphenyl)-propionitrile and 3β-diol, reducing AVP expression. These findings suggest that estradiol and T regulate AVP expression in SH-SY5Y cells through ERs, exerting a stimulatory action via ERα and an inhibitory action via ERβ. Topics: Arginine Vasopressin; Cell Line, Tumor; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Fulvestrant; Gene Expression Regulation, Neoplastic; Humans; Neuroblastoma; Nitriles; Phenols; Piperidines; Pyrazoles; Pyrimidines; Reverse Transcriptase Polymerase Chain Reaction; Testosterone | 2013 |
ZC88, a novel 4-amino piperidine analog, inhibits the growth of neuroblastoma cells through blocking hERG potassium channel.
Many studies have provided convincing evidence for hERG as an important diagnostic and prognostic factor in human cancers, as well as a useful target for antineoplastic therapy. Our previous study also revealed that knockdown of herg gene expression by shRNA interference inhibited the growth of neuroblastoma cells in vitro and in vivo. In the experiment, a novel 4-amino piperidine analog, ZC88, was examined for its effect on hERG potassium channels and its antitumor potency was observed in vitro and in vivo. The results showed that ZC88 could block hERG1 and hERG1b channels expressed in Xenopus oocytes in a concentration-dependent manner. ZC88 displayed significant antiproliferative activity in several tumor cell lines and the tumor cells with higher expression of hERG presented higher sensitivity to ZC88. The mitotic progression of tumor cells was markedly suppressed in the presence of ZC88 through arresting cells in G₀/G₁ phase. ZC88 significantly inhibited the tumor growth in nude mice at a dosage with slight influence on the cardiac QT interval. The antitumor effect of ZC88 was correlated at least partly with its blockage of hERG channels, which implicated a positive role of hERG potassium channel in tumor cell proliferation. Topics: Animals; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Ether-A-Go-Go Potassium Channels; Female; Guinea Pigs; Humans; Male; Mice; Mice, Nude; Neuroblastoma; Piperidines; Potassium Channel Blockers; Transfection; Xenograft Model Antitumor Assays; Xenopus laevis | 2013 |
Casuarinines A-J, lycodine-type alkaloids from Lycopodiastrum casuarinoides.
Ten new lycodine-type alkaloids, named casuarinines A-J (1-10), along with eight known analogues (11-18), were isolated from the whole plant of Lycopodiastrum casuarinoides . The new structures were established by spectroscopic methods and chemical transformations. Casuarinines A-D (1-4) and J (10) are common lycodine alkaloids possessing four connected six-membered rings, while tricyclic casuarinines E-H (5-8) are the piperidine ring cleavage products. In particular, casuarinine I (9) has an unprecedented five-membered tetrahydropyrrole ring instead of the piperidine ring. A plausible biosynthetic pathway to 9 is proposed. Among the compounds reported, casuarinine H (8) exhibited significant neuroprotective effect against hydrogen peroxide (H₂O₂)-induced neuronal cell damage in human neuroblastoma SH-SY5Y cells, while casuarinines C (3) and I (9) showed moderate inhibitory activity against acetylcholinesterase (AChE). Topics: Acetylcholinesterase; Alkaloids; Cholinesterase Inhibitors; Humans; Hydrogen Peroxide; Lycopodiaceae; Molecular Structure; Neuroblastoma; Neuroprotective Agents; Nuclear Magnetic Resonance, Biomolecular; Piperidines | 2013 |
5-HT2A serotonin receptor agonist DOI alleviates cytotoxicity in neuroblastoma cells: role of the ERK pathway.
Disturbances of serotonergic signaling, including the serotonin 2A (5-HT2A) receptor, have been implicated in neuropsychiatric and neurodegenerative disorders. The aim of the present study was to characterize the effect of a 5-HT2A receptor agonist on cytotoxicity in a neuronal cell line and address the involved mechanism. HTR2A mRNA and protein expression in human neuroblastoma SK-N-SH cells was confirmed. Cells were subjected to serum deprivation and cell viability was monitored continuously with xCELLigence. In a dose-response study the 5-HT2A agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) (25 nM to 5 μM) protected against serum deprivation cytotoxicity. The selective 5-HT2A receptor antagonist MDL 11,939, the general protein tyrosine kinase inhibitor genistein, and the extracellular signal-regulated kinase (ERK) pathway MEK inhibitor U0126, all attenuated DOI's protective effect. An antibody array suggested that 1 μM DOI affected phosphorylation of several tyrosine kinases. Western blot further confirmed that DOI transiently increased ERK phosphorylation, indicating its activation. Finally, protective concentrations of DOI increased cellular mitochondrial mass, an effect prevented by pretreatment with U0126. In conclusion, our results suggest that DOI protects SK-N-SH cells against serum deprivation through ERK pathway activation. They imply 5-HT2A receptor modulation as a potential target for neuroprotection. Topics: Amphetamines; Cell Line, Tumor; Cell Proliferation; Culture Media, Serum-Free; Dose-Response Relationship, Drug; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Humans; MAP Kinase Signaling System; Neuroblastoma; Organic Chemicals; Piperidines; Receptor, EphB3; Receptor, Serotonin, 5-HT2A; RNA, Messenger; Serotonin Antagonists; Serotonin Receptor Agonists; Time Factors | 2013 |
∆(9)-Tetrahydrocannabinol decreases NOP receptor density and mRNA levels in human SH-SY5Y cells.
Several studies demonstrated a cross-talk between the opioid and cannabinoid system. The NOP receptor and its endogenous ligand nociceptin/orphanin FQ represent an opioid-related functional entity that mediates some non-classical opioid effects. The relationship between cannabinoid and nociceptin/NOP system is yet poorly explored. In this study, we used the neuroblastoma SH-SY5Y cell line to investigate the effect of delta-9-tetrahydrocannabinol (∆(9)-THC) on nociceptin/NOP system. Results revealed that the exposure to ∆(9)-THC (100, 150, and 200 nM) for 24 h produces a dose-dependent NOP receptor B (max) down-regulation. Moreover, ∆(9)-THC caused a dose-dependent decrease in NOP mRNA levels. The selective cannabinoid receptor CB1 antagonist AM251 (1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide) reduces both effects, suggesting that ∆(9)-THC activation of CB1 receptor is involved in the observed effects. These data show evidence of a cross-talk between NOP and CB1 receptors, thus suggesting a possible interplay between cannabinoid and nociceptin/NOP system. Topics: Cell Line, Tumor; Dose-Response Relationship, Drug; Down-Regulation; Dronabinol; Gene Expression Regulation, Neoplastic; Humans; Neoplasm Proteins; Nerve Tissue Proteins; Neuroblastoma; Nociceptin Receptor; Piperidines; Protein Binding; Pyrazoles; Receptor, Cannabinoid, CB1; Receptors, Opioid; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Neoplasm | 2012 |
Dual inhibition of MAGL and type II topoisomerase by N-phenylmaleimides as a potential strategy to reduce neuroblastoma cell growth.
The endocannabinoid system is implicated in numerous physiopathological processes while more and more pieces of evidence wave the link between this complex machinery and cancer related phenomenon. In these lines, we confirmed the effects of 2-arachidonoylglycerol (2-AG), the main endocannabinoid, on neuroblastoma cells proliferation in vitro, and proved that some N-phenylmaleimide compounds that were previously shown as MAGL inhibitors can also inhibit type 2 topoisomerase. We also shed light on their antiproliferative effects on a neuroblastoma cell line. In order to establish a link between MAGL inhibition, topoisomerase inhibition and the effects on N1E-115 cells, we tested combinations of maleimides or known endocannabinoid metabolism inhibitors and 2-AG, the major MAGL substrate, on N1E-115 cells. However, none of the inhibitors tested, except the carbamate CAY10499, managed to increase 2-AG's effects. Even the MAGL reference inhibitor JZL184 failed to induce a stronger inhibition of proliferation. Topics: Antineoplastic Agents; Arachidonic Acids; Benzodioxoles; Cannabinoid Receptor Modulators; Carbamates; Cell Proliferation; DNA Topoisomerases, Type II; Endocannabinoids; Etoposide; Glycerides; Humans; Maleimides; Monoacylglycerol Lipases; Neuroblastoma; Oxadiazoles; Piperidines; Topoisomerase II Inhibitors; Tumor Cells, Cultured | 2012 |
Gintonin, a ginseng-derived lysophosphatidic acid receptor ligand, attenuates Alzheimer's disease-related neuropathies: involvement of non-amyloidogenic processing.
Ginseng extracts show cognition-enhancing effects in Alzheimer's disease (AD) patients. However, little is known about the active components and molecular mechanisms of how ginseng exerts its effects. Recently, we isolated a novel lysophosphatidic acid (LPA) receptor-activating ligand from ginseng, gintonin. AD is caused by amyloid-β protein (Aβ) accumulation. Aβ is derived from amyloid-β protein precursors (AβPPs) through the amyloidogenic pathway. In contrast, non-amyloidogenic pathways produce beneficial, soluble AβPPα (sAβPPα). Here, we describe our investigations of the effect of gintonin on sAβPPα release, Aβ formation, Swedish-AβPP transfection-mediated neurotoxicity in SH-SY5Y neuroblastoma cells, and Aβ-induced neuropathy in mice. Gintonin promoted sAβPPα release in a concentration- and time-dependent manner. Gintonin action was also blocked by the Ca2+ chelator BAPTA, α-secretase inhibitor TAPI-2, and protein-trafficking inhibitor brefeldin. Gintonin decreased Aβ1-42 release and attenuated Aβ1-40-induced cytotoxicity in SH-SY5Y cells. Gintonin also rescued Aβ1-40-induced cognitive dysfunction in mice. Moreover, in a transgenic mouse AD model, long-term oral administration of gintonin attenuated amyloid plaque deposition as well as short- and long-term memory impairment. In the present study, we demonstrated that gintonin mediated the promotion of non-amyloidogenic processing to stimulate sAβPPα release to restore brain function in mice with AD. Gintonin could be a useful agent for AD prevention or therapy. Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Analysis of Variance; Animals; Brain; Calcium; Calcium-Binding Proteins; Cell Survival; Disease Models, Animal; Donepezil; Dose-Response Relationship, Drug; Egtazic Acid; Enzyme Inhibitors; Glycoproteins; Humans; Indans; Isoxazoles; Ligands; Maze Learning; Memory Disorders; Metalloproteases; Mice; Mice, Transgenic; Microfilament Proteins; Mutation; Neuroblastoma; Nootropic Agents; Panax; Peptide Fragments; Phytotherapy; Piperidines; Plant Proteins; Presenilin-1; Propionates; Protein Binding; Receptors, Lysophosphatidic Acid; Signal Transduction; Time Factors; Transfection | 2012 |
Inhibition of voltage-gated K+ channels and Ca2+ channels by diphenidol.
Although diphenidol has long been deployed as an anti-emetic and anti-vertigo drug, its mechanism of action remains unclear. In particular, little is known as to how diphenidol affects neuronal ion channels. Recently, we showed that diphenidol blocked neuronal voltage-gated Na(+) channels, causing spinal blockade of motor function, proprioception and nociception in rats. In this work, we investigated whether diphenidol could also affect voltage-gated K(+) and Ca(2+) channels.. Electrophysiological experiments were performed to study ion channel activities in two neuronal cell lines, namely, neuroblastoma N2A cells and differentiated NG108-15 cells.. Diphenidol inhibited voltage-gated K(+) channels and Ca(2+) channels, but did not affect store-operated Ca(2+) channels.. Diphenidol is a non-specific inhibitor of voltage-gated ion channels in neuronal cells. Topics: Animals; Antiemetics; Calcium Channels; Cell Differentiation; Cell Line, Tumor; Electrophysiological Phenomena; Mice; Neuroblastoma; Piperidines; Potassium Channels, Voltage-Gated | 2012 |
Reciprocal potentiation of the antitumoral activities of FK866, an inhibitor of nicotinamide phosphoribosyltransferase, and etoposide or cisplatin in neuroblastoma cells.
NAD is an essential coenzyme involved in numerous metabolic pathways. Its principal role is in redox reactions, and as such it is not heavily "consumed" by cells. Yet a number of signaling pathways that bring about its consumption have recently emerged. This has brought about the hypothesis that the enzymes that lead to its biosynthesis may be targets for anticancer therapy. In particular, inhibition of the enzyme nicotinamide phosphoribosyl transferase has been shown to be an effective treatment in a number of preclinical studies, and two lead molecules [N-[4-(1-benzoyl-4-piperidinyl)butyl]-3-(3-pyridinyl)-2E-propenamide (FK866) and (E)-1-[6-(4-chlorophenoxy)hexyl]-2-cyano-3-(pyridin-4-yl)guanidine (CHS 828)] have now entered preclinical trials. Yet, the full potential of these drugs is still unclear. In the present study we have investigated the role of FK866 in neuroblastoma cell lines. We now confirm that FK866 alone in neuroblastoma cells induces autophagy, and its effects are potentiated by chloroquine and antagonized by 3-methyladenine or by down-regulating autophagy-related protein 7. Autophagy, in this model, seems to be crucial for FK866-induced cell death. On the other hand, a striking potentiation of the effects of cisplatin and etoposide is given by cotreatment of cells with ineffective concentrations of FK866 (1 nM). The effect of etoposide on DNA damage is potentiated by FK866 treatment, whereas the effect of FK866 on cytosolic NAD depletion is potentiated by etoposide. Even more strikingly, cotreatment with etoposide/cisplatin and FK866 unmasks an effect on mitochondrial NAD depletion. Topics: Acrylamides; Adenosine; Adenosine Triphosphate; Annexin A5; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Autophagy; Autophagy-Related Protein 7; Cell Death; Cell Line, Tumor; Cell Nucleus; Cell Survival; Chloroquine; Cisplatin; Comet Assay; DNA Damage; Down-Regulation; Drug Synergism; Etoposide; Humans; Immunohistochemistry; L-Lactate Dehydrogenase; Neuroblastoma; Nicotinamide Phosphoribosyltransferase; Piperidines; Ubiquitin-Activating Enzymes | 2011 |
The use of nitroxide radical-containing nanoparticles coupled with piperine to protect neuroblastoma SH-SY5Y cells from Aβ-induced oxidative stress.
The antioxidant effect and potential mechanism of nitroxide radical-containing nanoparticles (RNPs) coupled with piperine (PI) were investigated in human neuroblastoma SH-SY5Y cells. The effects of RNP/PI on SH-SY5Y cell lines was determined by WST assay for cell viability, nitroblue tetrazolium and deoxyribose assay for reactive oxygen species generation, ELISA assay for reactive oxygen species products and apoptotic cell death, and biochemical techniques for catalase and glutathione peroxidase activity. The RNP/PI significantly reduced the reactive oxygen species level and reactive oxygen species products compared with those of cells treated with RNPs alone. The RNP/PI treatment enhanced catalase and glutathione peroxidase activity. The combination of RNP/PI has been found to have an augmented antioxidant effect on an Alzheimer's model in vitro. The mechanism of the protective effect of this combination therapy was correlated in this study with its ability to reduce the generation of reactive oxygen species and prevent apoptosis via scavenging enzyme action pathways. Topics: Alkaloids; Amyloid beta-Peptides; Apoptosis; Benzodioxoles; Cell Line, Tumor; Humans; Nanoparticles; Neuroblastoma; Nitrogen Oxides; Oxidative Stress; Piperidines; Polyunsaturated Alkamides; Reactive Oxygen Species | 2011 |
A novel therapeutic combination for neuroblastoma: the vascular endothelial growth factor receptor/epidermal growth factor receptor/rearranged during transfection inhibitor vandetanib with 13-cis-retinoic acid.
High-risk cases of neuroblastoma have poor survival rates, and novel therapies are needed. Vandetanib (ZD6474, Zactima) is an inhibitor of the vascular endothelial growth factor receptor, epidermal growth factor receptor, and rearranged during transfection (RET) tyrosine kinases, which have each been implicated in neuroblastoma pathogenesis. The authors hypothesized that vandetanib combined with 13-cis-retinoic acid (CRA), a differentiating agent used in most current neuroblastoma treatment regimens, would be effective against neuroblastoma tumor models.. The authors evaluated the effects of vandetanib with and without CRA on RET phosphorylation and on the proliferation and survival of human neuroblastoma cell lines in vitro. Using a subcutaneous mouse xenograft model of human neuroblastoma, they analyzed tumors treated with CRA, vandetanib, and the combination of vandetanib plus CRA for growth, gross and histologic appearance, vascularity, and apoptosis.. Vandetanib treatment inhibited RET phosphorylation and resulted in induction of apoptosis in the majority of neuroblastoma cell lines in vitro, whereas CRA treatment induced morphologic differentiation and cell-cycle arrest. Treatment with vandetanib plus CRA resulted in more significant reduction in neuroblastoma cell viability than either alone. In a mouse xenograft model, the combination of vandetanib with CRA demonstrated significantly more growth inhibition than either alone, via both reduction in tumor vascularity and induction of apoptosis.. Vandetanib induces neuroblastoma tumor cell death in vitro and reduces tumor growth and vascularity in vivo. The combination of vandetanib with CRA was more effective in reducing tumor growth than either treatment alone. The antitumor effects of vandetanib plus CRA suggest a novel combination for use in neuroblastoma patients. Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA-Binding Proteins; ErbB Receptors; Humans; Isotretinoin; Mice; Neovascularization, Pathologic; Neuroblastoma; Phosphorylation; Piperidines; Quinazolines; Receptors, Vascular Endothelial Growth Factor; Tumor Suppressor Proteins; Xenograft Model Antitumor Assays | 2010 |
ALK, lung cancer, and personalized therapy: portent of the future?
Topics: Anaplastic Lymphoma Kinase; Antineoplastic Agents; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Crizotinib; Drug Resistance, Neoplasm; ErbB Receptors; Humans; Lung Neoplasms; Mutation; Neuroblastoma; Phosphatidylinositol 3-Kinases; Piperidines; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); Pyrazoles; Pyridines; ras Proteins; Receptor Protein-Tyrosine Kinases; Translocation, Genetic | 2010 |
Cell-produced alpha-synuclein is secreted in a calcium-dependent manner by exosomes and impacts neuronal survival.
alpha-Synuclein is central in Parkinson's disease pathogenesis. Although initially alpha-synuclein was considered a purely intracellular protein, recent data suggest that it can be detected in the plasma and CSF of humans and in the culture media of neuronal cells. To address a role of secreted alpha-synuclein in neuronal homeostasis, we have generated wild-type alpha-synuclein and beta-galactosidase inducible SH-SY5Y cells. Soluble oligomeric and monomeric species of alpha-synuclein are readily detected in the conditioned media (CM) of these cells at concentrations similar to those observed in human CSF. We have found that, in this model, alpha-synuclein is secreted by externalized vesicles in a calcium-dependent manner. Electron microscopy and liquid chromatography-mass spectrometry proteomic analysis demonstrate that these vesicles have the characteristic hallmarks of exosomes, secreted intraluminar vesicles of multivesicular bodies. Application of CM containing secreted alpha-synuclein causes cell death of recipient neuronal cells, which can be reversed after alpha-synuclein immunodepletion from the CM. High- and low-molecular-weight alpha-synuclein species, isolated from this CM, significantly decrease cell viability. Importantly, treatment of the CM with oligomer-interfering compounds before application rescues the recipient neuronal cells from the observed toxicity. Our results show for the first time that cell-produced alpha-synuclein is secreted via an exosomal, calcium-dependent mechanism and suggest that alpha-synuclein secretion serves to amplify and propagate Parkinson's disease-related pathology. Topics: alpha-Synuclein; Analysis of Variance; Animals; beta-Galactosidase; Brefeldin A; Calcium; Cell Death; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cells, Cultured; Cerebral Cortex; Chromatography, High Pressure Liquid; Culture Media, Conditioned; Cytotoxicity Tests, Immunologic; Dose-Response Relationship, Drug; Endocytosis; Exosomes; Gene Expression Regulation, Neoplastic; Humans; Hydrogen Peroxide; Immunoprecipitation; Mass Spectrometry; Microscopy, Confocal; Microscopy, Electron, Transmission; Molecular Weight; Multivesicular Bodies; Nerve Tissue Proteins; Neuroblastoma; Neurons; Peptides; Piperidines; Presenilin-1; Protein Synthesis Inhibitors; Pyrazoles; Rats; Receptors, Transferrin; Serum; Subcellular Fractions; Temperature; Transfection | 2010 |
Combination of vorinostat and flavopiridol is selectively cytotoxic to multidrug-resistant neuroblastoma cell lines with mutant TP53.
As p53 loss of function (LOF) confers high-level drug resistance in neuroblastoma, p53-independent therapies might have superior activity in recurrent neuroblastoma. We tested the activity of vorinostat, a histone deacetylase inhibitor, and flavopiridol, a pan-Cdk inhibitor, in a panel of multidrug-resistant neuroblastoma cell lines that included lines with wild-type (wt) and transcriptionally active TP53 (n = 3), mutated (mt), and LOF TP53 (n = 4) or p14(ARF) deletion (n = 1). The combination of vorinostat and flavopiridol was synergistic and significantly more cytotoxic (P < 0.001) in cell lines with p53-LOF and in the clones stably transfected with dominant-negative p53 plasmids. Cell cycle analysis by flow cytometry showed prominent cell-cycle arrest in G(2)/M (37%) for a cell line with wt TP53 (SK-N-RA) at 16 to 20 hours, while cells with mt TP53 (CHLA-90) slipped into sub-G(1) at 6 to 24 hours (25%-40% specific cell death). The morphological hallmarks of mitotic cell death, including defective spindle formation and abnormal cytokinesis, were detected by confocal microscopy after the treatment with vorinostat + flavopiridol combination in CHLA-90. The combination caused reduction in the expression of G(2)/M proteins (cyclin B1, Mad2, MPM2) in 2 cell lines with mt TP53 but not in those with wt TP53. Plk1 expression was reduced in all treated lines. Small interfering RNA knockdown of Mad2 and cyclin B1 or Plk1 synergistically reduced the clonogenicity of CHLA-90 cells. The combination of HDAC inhibitor and flavopiridol may be a unique approach to treating neuroblastomas with p53 LOF, one that evokes induction of mitotic failure. Topics: Biomarkers, Tumor; Cell Death; Cell Line, Tumor; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Synergism; Flavonoids; G2 Phase; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Mitosis; Mutant Proteins; Mutation; Neuroblastoma; Piperidines; Protein Kinase Inhibitors; Tumor Suppressor Protein p53; Vorinostat | 2010 |
Additive protective effects of donepezil and nicotine against salsolinol-induced cytotoxicity in SH-SY5Y cells.
Although the etiology of Parkinson's disease (PD) remains elusive, a number of toxins including elevated salsolinol, an endogenous metabolite of dopamine may contribute to its pathology. It was reported recently that nicotine may have protective effects against salsolinol-induced toxicity in human neuroblastoma derived SH-SY5Y cells and that these effects of nicotine are mediated by nicotinic receptors. Donepezil (Aricept) is a reversible non-competitive acetylcholinesterase inhibitor that is approved for use in mild to moderate Alzheimer's disease. The increase in acetylcholine concentrations is believed to be the major contributory factor in donepezil's therapeutic efficacy. However, cholinesterase inhibitors may also directly interact with nicotinic receptors and possess neuroprotective properties. In this study, we sought to determine whether donepezil may have protective effects against salsolinol-induced toxicity in SH-SY5Y cells and whether the combination of donepezil and nicotine may result in additive protection. Moreover, it was of interest to elucidate the role of nicotinic receptors as well as cell cycle and apoptosis in mechanism of action of these compounds. SH-SY5Y cells were exposed to 0.6 mM salsolinol with and without various drug pretreatments for 48 h. Nicotine (50 muM) resulted in approximately 54% protection and donepezil (5 muM) resulted in approximately 40% protection, and the combination of the two resulted in an additive (approximately 93%) protection against salsolinol-induced toxicity. Salsolinol caused an arrest of the cells in G(1)-phase of cell cycle and an increase in apoptotic indices that were blocked by the combination of donepezil and nicotine. Mecamylamine, a non-selective nicotinic receptor antagonist completely blocked the effects of nicotine and partially attenuated the effects of donepezil. A combination of atropine, a muscarinic receptor antagonist and mecamylamine completely blocked the effects of donepezil, indicating involvement of both nicotinic and muscarinic receptors in donepezil's actions. The findings suggest a therapeutic potential for the combination of donepezil and nicotine in PD. Topics: Analysis of Variance; Annexin A5; Apoptosis; Atropine; Cell Cycle; Cell Line, Tumor; Cell Survival; Cholinesterase Inhibitors; Donepezil; Dose-Response Relationship, Drug; Drug Combinations; Drug Interactions; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Indans; Mecamylamine; Neuroblastoma; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Piperidines; Propidium; Salsoline Alkaloids | 2009 |
Attenuation of methamphetamine-induced effects through the antagonism of sigma (sigma) receptors: Evidence from in vivo and in vitro studies.
Methamphetamine (METH) and many other abused substances interact with sigma receptors. sigma receptors are found on dopaminergic neurons and can modulate dopaminergic neurotransmission. Antisense knock down of sigma receptors also mitigates METH-induced stimulant effects, suggesting that these proteins are viable medication development targets for treating psychostimulant abuse. In the present study, AC927, a sigma receptor antagonist, was evaluated for its ability to attenuate METH-induced effects in vivo and in vitro. Radioligand binding studies showed that AC927 had preferential affinity for sigma receptors compared to 29 other receptors, transporters and ion channels. Pretreatment of male, Swiss Webster mice with AC927 significantly attenuated METH-induced locomotor stimulation, striatal dopamine depletions, striatal dopamine transporter reductions, and hyperthermia. When the neurotoxicity of METH was further examined in vitro under temperature-controlled conditions, co-incubation with AC927 mitigated METH-induced cytotoxicity. Together, the results demonstrate that AC927 protects against METH-induced effects, and suggests a new strategy for treating psychostimulant abuse. Topics: Animals; Behavior, Animal; Body Temperature; Brain; Cell Line, Tumor; Cell Shape; Cytokines; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopamine Uptake Inhibitors; Dose-Response Relationship, Drug; Male; Methamphetamine; Mice; Motor Activity; Neuroblastoma; Oxalates; Piperidines; Protein Binding; Radioligand Assay; Random Allocation; Rats; Rats, Sprague-Dawley; Receptors, sigma; Time Factors | 2008 |
Constitutive activity at the cannabinoid CB1 receptor is required for behavioral response to noxious chemical stimulation of TRPV1: antinociceptive actions of CB1 inverse agonists.
The potential modulation of TRPV1 nociceptive activity by the CB(1) receptor was investigated here using CB(1) wild-type (WT) and knock-out (KO) mice as well as selective CB(1) inverse agonists. No significant differences were detected in baseline thermal thresholds of ICR, CB(1)WT or CB(1)KO mice. Intraplantar capsaicin produced dose- and time-related paw flinch responses in ICR and CB(1)WT mice and induced plasma extravasation yet minimal responses were seen in CB(1)KO animals with no apparent differences in TRPV1 channel expression. Capsaicin-evoked CGRP release from spinal cord tissue and capsaicin-evoked action potentials on isolated skin-nerve preparation were significantly decreased in CB(1)KO mice. Pretreatment with intraplantar galanin and bradykinin, compounds known to sensitize TRPV1 receptors, restored capsaicin-induced flinching in CB(1)KO mice. The possibility that constitutive activity at the CB(1) receptor is required to maintain the TRPV1 receptor in a "sensitized" state was tested using CB(1) inverse agonists. The CB(1) inverse agonists elicited concentration-related inhibition of capsaicin-induced calcium influx in F-11 cells and produced dose-related inhibition of capsaicin-induced flinching in ICR mice. These data suggest that constitutive activity at the CB(1) receptor maintains the TRPV1 channel in a sensitized state responsive to noxious chemical stimuli. Treatment with CB(1) inverse agonists may promote desensitization of the channel resulting in antinociceptive actions against chemical stimulus modalities. These studies propose possible therapeutic exploitation of a novel mechanism providing pain relief by CB(1) inverse agonists. Topics: Analysis of Variance; Animals; Behavior, Animal; Bradykinin; Calcitonin Gene-Related Peptide; Calcium; Capsaicin; Cell Line, Tumor; Dose-Response Relationship, Drug; Galanin; Gene Expression Regulation; Male; Mice; Mice, Inbred ICR; Mice, Knockout; Morphine; Narcotics; Nerve Fibers, Unmyelinated; Neuroblastoma; Pain; Pain Measurement; Pain Threshold; Piperidines; Pyrazoles; Rats; Reaction Time; Receptor, Cannabinoid, CB1; Rimonabant; Stimulation, Chemical; Sulfonamides; TRPV Cation Channels | 2008 |
Cannabinoid receptor-mediated translocation of NO-sensitive guanylyl cyclase and production of cyclic GMP in neuronal cells.
Cannabinoid agonists regulate NO and cyclic AMP production in N18TG2 neuroblastoma cells, leading to the hypothesis that neuronal cyclic GMP production could be regulated by CB(1) cannabinoid receptors. NO (nitric oxide)-sensitive guanylyl cyclase (GC) is a heterodimeric cytosolic protein that mediates the down-stream effects of NO. Genes of proteins in the cyclic GMP pathway (alpha(1), alpha(2), and beta(1) subunits of NO-sensitive GC and PKG1, but not PKG2) were expressed in N18TG2 cells, as was the CB(1) but not the CB(2) cannabinoid receptor. Stimulation of N18TG2 cells by cannabinoid agonists CP55940 and WIN55212-2 increased cyclic GMP levels in an ODQ-sensitive manner. GC-beta(1) in membrane fractions was increased after 5 or 20 min stimulation, and was significantly depleted in the cytosol by 1h. The cytosolic pool of GC-beta(1) was replenished after 48 h of continued cannabinoid drug treatment. Translocation of GC-beta(1) from the cytosol was blocked by the CB(1) antagonist rimonabant (SR141716) and by the Gi/o inactivator pertussis toxin, indicating that the CB(1) receptor and Gi/o proteins are required for translocation. Long-term treatment with rimonabant or pertussis toxin reduced the amount of GC-beta(1) in the cytosolic pool. We conclude that CB(1) receptors stimulate cyclic GMP production and that intracellular translocation of GC from cytosol to the membranes is intrinsic to the mechanism and may be a tonically active or endocannabinoid-regulated process. Topics: Animals; Cannabinoids; Cell Line, Tumor; Cyclic GMP; Drug Interactions; Enzyme Inhibitors; Gene Expression; Guanylate Cyclase; Mice; Neuroblastoma; Nitric Oxide; Pertussis Toxin; Piperidines; Protein Transport; Pyrazoles; Receptor, Cannabinoid, CB1; Rimonabant; Time Factors | 2008 |
Potent antitumor effects of ZD6474 on neuroblastoma via dual targeting of tumor cells and tumor endothelium.
Among children with relapsed or refractory neuroblastoma, the prognosis is poor and novel therapeutic strategies are needed to improve long-term survival. As with other solid tumors, high vascular density within neuroblastoma is associated with advanced disease, and therapeutic regimens directed against the tumor vasculature may provide clinical benefit. The receptor tyrosine kinase RET is widely expressed in neuroblastoma and is known to activate key signal transduction pathways involved in tumor cell survival and progression including Ras/mitogen-activated protein kinase and phosphatidylinositol 3-kinase/Akt. We investigated the effect of dual targeting of tumor cells and tumor endothelium with ZD6474, a small-molecule tyrosine kinase inhibitor of vascular endothelial growth factor (VEGF) receptor 2, epidermal growth factor receptor, and RET. ZD6474 inhibited the phosphorylation of RET in neuroblastoma cells and had a direct effect on tumor cell viability in seven neuroblastoma cell lines. In a human neuroblastoma xenograft model, ZD6474 inhibited tumor growth by 85% compared with treatment with vehicle alone. In contrast, no significant inhibition of tumor growth was observed after treatment with bevacizumab, an antihuman VEGF monoclonal antibody, or the epidermal growth factor receptor inhibitor erlotinib, either alone or in combination. Immunohistochemical analysis showed that ZD6474 treatment led to an increase in endothelial cell apoptosis along with inhibition of VEGF receptor-2 activation on tumor endothelium. In conclusion, dual targeting of tumor cells, potentially through RET inhibition, and tumor vasculature with ZD6474 leads to potent antitumor effects. This approach merits further investigation for patients with neuroblastoma. Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Proliferation; Cell Survival; Drug Delivery Systems; Endothelium; ErbB Receptors; Humans; Male; Mice; Mice, Nude; Neuroblastoma; Phosphorylation; Piperidines; Proto-Oncogene Proteins c-ret; Quinazolines; Tumor Cells, Cultured; Vascular Endothelial Growth Factor Receptor-2; Xenograft Model Antitumor Assays | 2008 |
Neurosteroids alter glutamate-induced changes in neurite morphology of NG108-15 cells.
Activation of the NMDA receptor leads to increased intracellular Ca2+ levels ([Ca2+]i) which induces outgrowth of and morphologic changes in the neurites of the NG108-15 cell line. This effect can be blocked by antagonists for this glutamate receptor subtype (e.g. ifenprodil or AP5). We have previously shown that nanomolar concentrations of various neurosteroids modulate ifenprodil binding to the NMDA receptor. To investigate whether this interaction affects the functioning of the receptor, we studied the effect of 24 and 48 h of pregnenolone sulphate (PS) or pregnanolone sulphate (3alpha5betaS) on glutamate-stimulated NG108-15 cells. Unexpectedly, the neurosteroids themselves had an inhibitory effect on glutamate-induced changes in neurite patterns. This effect was comparable to that of ifenprodil or AP5. Moreover, the effect of combined treatment with 3alpha5betaS and ifenprodil on neurite morphology indicated a functional interaction between the substances. Interestingly, PS induced cell detachment over time, an effect that was further enhanced by ifenprodil. Cell detachment was also seen after 48 h of treatment with 3alpha5betaS; however, the effect was blocked by ifenprodil and weaker than that of PS. The interaction with the NR2B-selective antagonist ifenprodil indicates that this NMDA receptor subunit may be involved in neurosteroid-induced NG108-15 cell detachment. Topics: 2-Amino-5-phosphonovalerate; Cell Adhesion; Cell Line, Tumor; Excitatory Amino Acid Agonists; Glioma; Glutamic Acid; Humans; Hybrid Cells; Neurites; Neuroblastoma; Piperidines; Pregnenolone; Receptors, N-Methyl-D-Aspartate; Steroids | 2007 |
Cleft-type cyclophanes confer neuroprotection against excitatory neurotoxicity in vitro and in vivo through inhibition of NMDA receptors.
The cleft-type cyclophanes (ACCn, DNCn and TsDCn) were found to strongly inhibit macroscopic currents at heteromeric NMDA receptors (NR1/NR2) but not AMPA receptors expressed in Xenopus oocytes at voltage-clamp recording. The inhibition by cleft-type cyclophanes was voltage-dependent, because the inhibition was larger at -100 mV than at -20 mV. Mutations at NR1 N650, located in the vestibule of the channel pore, reduced the inhibition by DNCn and TsDCn, suggesting that the residue (N650) interacts with these cleft-type cyclophanes. Cell toxicity of TsDCn on SH-SY5Y cells was slightly weaker than that of memantine. The neuroprotective effects of cleft-type cyclophanes against cell damage caused by NMDA were investigated in cultured rat hippocampal neurons. Addition of 10 microM DNCn or TsDCn into the medium ablated the neurotoxicity induced by NMDA, and a similar effect was also observed with memantine. The neuroprotective effects of cleft-type cyclophanes were then assayed on NMDA-induced seizures in mice. Intracerebroventricular injection of TsDCn (5 mg/mouse) decreased the seizure induced by intraperitoneal injection of NMDA (115 mg/kg) in mice. The results demonstrate that these cleft-type cyclophanes interact directly with the extracellular mouth of the NMDA channel pore and exhibit neuroprotective effects on NMDA-induced excitatory toxicity in primary cultured neurons and mice. Topics: Animals; Cell Line, Tumor; Ethers, Cyclic; Female; Hippocampus; Larva; Mice; N-Methylaspartate; Neuroblastoma; Neurons; Neuroprotective Agents; Neurotoxins; Piperidines; Rats; Receptors, N-Methyl-D-Aspartate; Seizures; Xenopus | 2007 |
The NK1 receptor is involved in the antitumoural action of L-733,060 and in the mitogenic action of substance P on neuroblastoma and glioma cell lines.
We have carried out an in vitro study to investigate the ability of substance P to activate cell growth and the NK1 receptor antagonist L-733,060 to inhibit cell growth in the SKN-BE(2) neuroblastoma and GAMG glioma cell lines. A coulter counter was used to determine viable cell numbers, followed by application of the tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)2-(4-sulfophenyl)-2H-tetrazolium], inner salt, colorimetric method to evaluate cell viability in this cytotoxicity assay. Nanomolar concentrations of substance P increased, and micromolar concentrations of L-733,060 inhibited the growth of both cell lines studied, with and without previous administration of substance P. In addition, we have demonstrated by immunoblot analysis that NK1 receptors are present in both cancer cell lines studied here. Thus, this study demonstrates that substance P acts as a mitogen in the SKN-BE(2) neuroblastoma and GAMG glioma cell lines, and that the antitumoural action of L-733,060 on both human cell lines occurs through the NK1 receptor. This action suggests that the NK1 receptor is a new and promising target in the treatment of human neuroblastoma and glioma. Topics: Antineoplastic Agents; Brain Neoplasms; Cell Division; Cell Line, Tumor; Glioma; Humans; Mitogens; Neuroblastoma; Piperidines; Receptors, Neurokinin-1; Substance P | 2005 |
Unequal neuroprotection afforded by the acetylcholinesterase inhibitors galantamine, donepezil, and rivastigmine in SH-SY5Y neuroblastoma cells: role of nicotinic receptors.
Donepezil, rivastigmine, and galantamine are three drugs with acetylcholinesterase (AChE)-inhibiting activity that are currently being used to treat patients suffering from Alzheimer's disease. We have studied the neuroprotective effects of these drugs, in comparison with nicotine, on cell death caused by beta-amyloid (Abeta) and okadaic acid, two models that are relevant to Alzheimer's pathology, in the human neuroblastoma cell line SH-SY5Y. Galantamine and donepezil showed a U-shaped neuroprotective curve against okadaic acid toxicity; maximum protection was achieved at 0.3 microM galantamine and at 1 microM donepezil; at higher concentrations, protection was diminished. Rivastigmine showed a concentration-dependent effect; maximum protection was achieved at 3 microM. When apoptosis was induced by Abeta25-35, galantamine, donepezil, and rivastigmine showed maximum protection at the same concentrations: 0.3, 1, and 3 microM, respectively. Nicotine also afforded protection against Abeta- and okadaic acid-induced toxicity. The neuroprotective effects of galantamine, donepezil, and nicotine were reversed by the alpha7 nicotinic antagonist methyllycaconitine but not by the alpha4beta2 nicotinic antagonist dihydro-beta-erythroidine. The phosphoinositide 3-kinase (PI3K)-Akt blocker 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) reversed the protective effects of galantamine, donepezil, and nicotine but not that of rivastigmine. In contrast, the bcl-2 antagonist ethyl[2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)]-4H-chromene-3-carboxylate (HA 14-1) reversed the protective effects of the three AChE inhibitors and that of nicotine. Our results show that galantamine, donepezil, and rivastigmine afford neuroprotection through a mechanism that is likely unrelated to AChE inhibition. Such neuroprotection seemed to be linked to alpha7 nicotinic receptors and the PI3K-Akt pathway in the case of galantamine and donepezil but not for rivastigmine. Topics: Aconitine; Amyloid beta-Peptides; Apoptosis; Benzopyrans; Cell Culture Techniques; Cell Line, Tumor; Cholinesterase Inhibitors; Chromones; Donepezil; Dose-Response Relationship, Drug; Enzyme Inhibitors; Galantamine; Humans; Indans; L-Lactate Dehydrogenase; Morpholines; Neuroblastoma; Neuroprotective Agents; Nicotine; Nitriles; Okadaic Acid; Phenylcarbamates; Phosphatidylinositol 3-Kinases; Piperidines; Proto-Oncogene Proteins c-bcl-2; Receptors, Nicotinic; Rivastigmine | 2005 |
Antitumoural action of L-733,060 on neuroblastoma and glioma cell lines.
We have performed an in vitro study of the growth-inhibitory capacity of the potent and long-acting NK1 receptor antagonist L-733,060, at concentrations ranging from 2.5 microM to 20 microM, against the neuroblastoma cell line SKN-BE(2) and 10 microM to 25 microM for glioma cell line GAMG. Coulter counter was used to determine viable cell numbers, followed by application of the tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)2-(4-sulfophenyl)-2H-tetrazolium], inner salt colorimetric method to evaluate cell viability in this cytotoxicity assay. L-733,060 inhibited the growth of the two cell lines studied in a dose-dependent manner. The IC 50 values were 11.6 microM (30h) and 10.2 microM (72h) for SKN-BE(2); and 21.3 microM (48h) and 19.9 microM (96h) for GAMG. These findings indicate that the NK1 receptor antagonist L-733,060 acts as a broad-spectrum antitumoural agent. This new action, reported here for the first time, suggests that the NK1 receptor antagonist L-733,060 could be a promising therapeutic drug for the treatment of human neuroblastoma and human glioma. Topics: Antineoplastic Agents; Brain Neoplasms; Cell Division; Cell Line, Tumor; Dose-Response Relationship, Drug; Glioma; Humans; Neuroblastoma; Neurokinin-1 Receptor Antagonists; Piperidines; Receptors, Neurokinin-1; Substance P | 2004 |
Acetylcholinesterase inhibitors increase ADAM10 activity by promoting its trafficking in neuroblastoma cell lines.
Acetylcholinesterase inhibitors (AChEIs) are the only currently available drugs for treating Alzheimer's Disease (AD). Some authors have suggested a function of AChEIs not only in the induction of AChE overproduction and alternative splicing shifts but also a possible role of these drugs in amyloid metabolism beyond their well-known symptomatic effect. Here, we investigate the mechanisms of action of the AChEI donepezil on APP (amyloid precursor protein) metabolism and on the activity/trafficking of the alpha-secretase candidate ADAM 10, in differentiated human neuroblastoma cells (SH-SY5Y). In these cells, the activity of AChE is significantly decreased after 2 h of donepezil treatment. Further, SH-SY5Y cells released significantly more sAPPalpha into the medium, whereas total APP levels in cell lysates were unchanged. Interestingly, treated cells showed increased ADAM 10 levels in membrane compartments. This effect was prevented by pretreatment with tunicamycin or brefeldin, suggesting that donepezil affects trafficking and/or maturation of ADAM 10; additionally, this pretreatment significantly decreased sAPPalpha levels. Pre-incubation with atropine decreased release of sAPPalpha significantly but did not revert ADAM 10 activity to control levels further suggesting that donepezil acts not solely through a purely receptor mediated pathway. These findings indicate that donepezil exerts multiple mechanisms involving processing and trafficking of key proteins involved in AD pathogenesis. Topics: Acetylcholinesterase; ADAM Proteins; ADAM10 Protein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Atropine; Blotting, Western; Brefeldin A; Bungarotoxins; Carbachol; Cell Differentiation; Cell Fractionation; Cell Line, Tumor; Cholinergic Agonists; Cholinesterase Inhibitors; Donepezil; Drug Interactions; Embryo, Mammalian; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Indans; Membrane Proteins; Metalloendopeptidases; Microscopy, Confocal; Muscarinic Antagonists; Neuroblastoma; Physostigmine; Piperidines; Protein Synthesis Inhibitors; Protein Transport; Tretinoin | 2004 |
Induction of apoptosis by flavopiridol in human neuroblastoma cells is enhanced under hypoxia and associated with N-myc proto-oncogene down-regulation.
Neuroblastoma is the most common extracranial solid tumor of children that arises from the sympathetic nervous system. Survival rates for neuroblastoma patients is low despite intensive therapeutic intervention, and the identification of new effective drugs remains a primary goal. The cyclin-dependent kinase inhibitor, flavopiridol, has demonstrated growth-inhibitory and cytotoxic activity against various tumor types. Our aim was to investigate flavopiridol effects on advanced-stage, N-myc proto-oncogene (MYCN)-amplified human neuroblastomas and the modulation of its activity by hypoxia, a critical determinant of tumor progression and a major challenge of therapy.. Cell viability was monitored by 3-(4,5 dimethyl-2 thiazolyl)-2,5 diphenyl-2H tetrazolium bromide (MTT) and trypan blue dye exclusion assays; DNA synthesis was assessed with the bromodeoxyuridine pulse-labeling technique; apoptosis was studied by Giemsa staining, DNA fragmentation, terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling reaction, flow cytometric determination of hypodiploid DNA content, and evaluation of caspase activity and cytochrome c (CytC) release; MYCN expression was determined by Northern and Western blotting.. Flavopiridol caused dose- and time-dependent decreases in neuroblastoma viability by inducing apoptosis, as confirmed by morphologic and biochemical criteria. Cell death was preceded by DNA synthesis inhibition and G1-G2 arrest, reversed by the pancaspase inhibitor, zVAD-fmk, and associated with caspase-3 and -2 activation and CytC increase. Moreover, flavopiridol strongly down-regulated MYCN mRNA and protein expression. Exposure to hypoxia enhanced both the extent of apoptosis and flavopiridol effects on CytC, caspase 3, and MYCN.. These results indicate that flavopiridol has growth-inhibitory and apoptotic activity against advanced-stage neuroblastomas in vitro and is worthy of further investigation for the treatment of this disease. Topics: Apoptosis; Bromodeoxyuridine; Caspases; Cell Hypoxia; Cell Survival; Cyclin-Dependent Kinases; Cytochromes c; DNA; Down-Regulation; Enzyme Activation; Enzyme Inhibitors; Flavonoids; G1 Phase; G2 Phase; Genes, myc; Growth Inhibitors; Humans; Hypoxia; In Situ Nick-End Labeling; Neuroblastoma; Piperidines; Proto-Oncogene Mas; Tetrazolium Salts; Thiazoles; Tumor Cells, Cultured | 2004 |
Block of erg current by linoleoylamide, a sleep-inducing agent, in pituitary GH3 cells.
Linoleoylamide is physiological constituent of neurons. The effects of this agent, also a sleep-inducing agent, on ion currents in pituitary GH(3) cells were investigated. Hyperpolarization-elicited K(+) currents in GH(3) cells bathed in a high-K(+), Ca(2+)-free solution were studied to determine the effects of linoleoylamide and other related compounds on the I(K(IR)) that was sensitive to inhibition by E-4031 and identified as an erg (ether-à-go-go-related-gene) current. Linoleoylamide suppressed the amplitude of I(K(IR)) in a concentration-dependent manner with an IC(50) value of 5 microM. Oleamide (20 microM) inhibited the amplitude of I(K(IR)), while neither arachidonic acid (20 microM) nor 14,15-epoxyeicosatrienoic acid (20 microM) had an effect on it. In GH(3) cells incubated with anandamide (20 microM) or arachidonic acid (20 microM), the linoleoylamide-induced inhibition of I(K(IR)) remained unaltered. In inside-out patches, arachidonic acid (20 microM) and 14,15-epoxyeicosatrienoic acid (20 microM) stimulated large-conductance Ca(2+)-activated K(+) channels; however, linoleoylamide (20 microM) had little or no effect on them. Under current-clamp mode, linoleoylamide (20 microM) increased the firing rate. In IMR-32 neuroblastoma cells, linoleoylamide also suppressed I(K(IR)). This study provides the evidence that linoleoylamide has a depressant effect on the erg current, and suggests that this effect may affect hormonal secretion. Topics: 8,11,14-Eicosatrienoic Acid; alpha-Linolenic Acid; Amides; Animals; Arachidonic Acid; Arachidonic Acids; Calcium; Calcium Channels, L-Type; Dose-Response Relationship, Drug; Endocannabinoids; Humans; Hydantoins; Imidazoles; Imidazolidines; Infant, Newborn; Linoleic Acids; Membrane Potentials; Neuroblastoma; Patch-Clamp Techniques; Piperazines; Piperidines; Pituitary Neoplasms; Polyunsaturated Alkamides; Potassium Channels; Pyridines; Tumor Cells, Cultured | 2003 |
Pharmacological characterization of AR-M1000390 at human delta opioid receptors.
We investigated the pharmacological properties of a newly synthesised delta agonist AR-M1000390, derived from SNC-80 ((+)-4-[(alpha R)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethyl-benzamide), in the neuroblastoma cell line SK-N-BE expressing only human delta-opioid receptors. Binding and functional experiments showed a weak affinity (K(i) = 106 +/- 34 nM) correlated with a weak potency (EC(50) = 111 +/- 31 nM) to inhibit the forskolin-stimulated cAMP accumulation. Sustained activation of opioid receptors in the presence of the maximal inhibitory concentration of AR-M1000390 produced a rapid and strong desensitization. In order to examine the contribution of internalization and down-regulation in the desensitization processes, binding and functional experiments were conducted in the presence or in the absence of hypertonic sucrose solution to block clathrin-dependent opioid receptor endocytosis. We observed both the inability of AR-M1000390 to down-regulate opioid receptors and the absence of any effect of sucrose on desensitization. The lack of delta-opioid receptor internalization by AR-M1000390 was further corroborated by confocal microscopy using antibodies directed either against the endogenous delta-opioid receptors or the FLAG-tagged delta-opioid receptors stably expressed in the SK-N-BE cells. These data suggest that uncoupling rather than internalization is responsible for delta-opioid receptors desensitization by AR-M1000390. Topics: Adenylyl Cyclases; Benzamides; Down-Regulation; Endocytosis; Humans; Microscopy, Confocal; Narcotic Antagonists; Neuroblastoma; Piperazines; Piperidines; Receptors, Opioid, delta; Signal Transduction; Sucrose; Tumor Cells, Cultured | 2003 |
Flavopiridol inhibits vascular endothelial growth factor production induced by hypoxia or picolinic acid in human neuroblastoma.
Human neuroblastoma (NB) tumors elaborate angiogenic peptides, and enhanced angiogenesis correlates with their aggressive behavior, metastatic spread and poor clinical outcome. Hence, inhibition of angiogenic factor production may represent a potential therapeutic target for NB treatment. There is currently little information regarding the stimuli that control NB production of angiogenic mediators. In this study, we analyzed the effects of hypoxia, a common feature of solid tumors and a major drive to tumor angiogenesis, and of PA, a tryptophan catabolite produced under inflammatory conditions and endowed with several biologic properties, on the production of the angiogenic activator VEGF by advanced-stage human NB cell lines. We demonstrate that both stimuli are potent inducers of VEGF expression and secretion. VEGF upregulation by PA involved iron chelation because iron sulfate prevented this effect whereas the iron-chelating agent DFX induced VEGF production. Conversely, the CDK inhibitor Flp completely blocked VEGF induction by hypoxia. This effect occurred as early as 3 hr after stimulation and did not require de novo protein synthesis. Moreover, Flp exerted similar inhibitory activity on VEGF induction by PA or DFX, suggesting that this compound targets an essential step in the signaling pathway that leads to VEGF expression. Our findings demonstrate that PA can modulate angiogenic factor production by tumor cells and establish the importance of Flp as an inhibitor of VEGF production by human NB. Topics: Antineoplastic Agents; Cell Hypoxia; Deferoxamine; Endothelial Growth Factors; Ferrous Compounds; Flavonoids; Gene Expression; Humans; Iron Chelating Agents; Lymphokines; Neuroblastoma; Picolinic Acids; Piperidines; RNA, Messenger; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors | 2002 |
Three vasoactive peptides, endothelin-1, adrenomedullin and urotensin-II, in human tumour cell lines of different origin: expression and effects on proliferation.
Evidence has accumulated showing that vasoactive peptides, such as endothelin-1, adrenomedullin and urotensin-II, are expressed in various kinds of tumour cells. In the present study, the expression of endothelin-1 and endothelin receptors was studied in eight human tumour cell lines: T98G (glioblastoma), IMR-32 and NB69 (neuroblastoma), BeWo (choriocarcinoma), SW-13 (adrenocortical carcinoma), DLD-1 (colonic carcinoma), HeLa (cervical carcinoma) and VMRC-RCW (renal carcinoma). Reverse transcriptase-PCR showed expression of endothelin-1 mRNA in seven out of the eight cell lines, the exception being BeWo cells. ET(A) receptor mRNA was expressed in T98G, IMR-32 and NB69 cells, but weakly in the other cells. ET(B) receptor mRNA was expressed in IMR-32, NB69 and BeWo cells, but only weakly in T98G and HeLa cells. Immunoreactive endothelin was detected in the culture media of six out of the eight cell lines, but not in that of IMR-32 or BeWo cells. Treatment of T98G cells with an anti-endothelin-1 antibody or an anti-adrenomedullin antibody for 24 h decreased cell numbers to approx. 84% and 90% of control respectively. Treatment with the ET(A) receptor antagonist BQ-610 (1 microM) significantly decreased cell number to about 90% of control, whereas the ET(B) receptor antagonist BQ-788 had no significant effect. On the other hand, exogenously added endothelin-1, adrenomedullin or urotensin-II (0.1 microM) had no significant effects on cell number. These results suggest that endothelin-1 acts as a paracrine or autocrine growth stimulator in tumours. The effect of endothelin-1 on tumour growth appears to be mediated by the ET(A) receptor. Topics: Adrenal Cortex Neoplasms; Adrenomedullin; Antibodies, Monoclonal; Cell Division; Choriocarcinoma; Colonic Neoplasms; Endothelin Receptor Antagonists; Endothelin-1; Glioblastoma; Growth Substances; HeLa Cells; Humans; Kidney Neoplasms; Neuroblastoma; Oligopeptides; Peptides; Piperidines; Receptor, Endothelin A; Receptor, Endothelin B; RNA, Messenger; Tumor Cells, Cultured; Urotensins; Vasodilator Agents | 2002 |
[Protective effects of tacrine and donepezil against staurosporine-induced apoptotic death].
To study whether tacrine and donepezil can prevent cell apoptosis induced by staurosporine in NG108-15 and Hela cell lines.. MTT assay was used to examine if staurosporine impairs cell metabolism. Phase-contrast and fluorescence microscope were used to examine cell morphological changes. DNA was isolated and electrophoretically separated on 1% agarose gel to observe if there were DNA fragments. Western blot was made to analyse protein levels of anti-apoptotic Bcl-2 and proapoptotic Bax.. NG108-15 cells treated with 0.1 mumol.L-1 staurosporine for 12-24 hours exhibited marked cell death and DNA fragmentation. Pre-treatment with 0.1 mmol.L-1 tacrine provided approximately 40% protective effect and resulted in obvious inhibition or delay of DNA fragmentation. Moreover, NG108-15 cells treated with tacrine became elongated and polarized, and showed longer processes than control cells. Pretreatment with 0.1 mmol.L-1 tacrine significantly increased the expression of Bcl-2 protein level and delayed the staurosporine-induced increase of Bax protein expression. However, donepezil did not show any protective effect on the cell impairment induced by staurosporine in NG108-15 cells. In Hela cells 0.1 mumol.L-1 staurosporine also induced significant cell injury, but pretreatment with tacrine and donepezil did not provide any obvious protective effect against this cell damage.. Donepezil did not provide obvious protective effect against apoptosis, and protective effects of tacrine might not be mediated through AChE inhibition. Protective effects of tacrine against staurosporine-induced injury might be selective to different cells. Topics: Animals; Apoptosis; Cholinesterase Inhibitors; Donepezil; Glioma; HeLa Cells; Humans; Hybrid Cells; Indans; Mice; Neuroblastoma; Piperidines; Protective Agents; Rats; Staurosporine; Tacrine | 2002 |
The cannabinoid agonist DALN positively modulates L-type voltage-dependent calcium-channels in N18TG2 neuroblastoma cells.
The present study demonstrates a novel stimulatory effect of a cannabinoid agonist on calcium channels. DALN (1 nM) potentiated 45Ca(2+)-uptake by N18TG2 neuroblastoma cells, an effect that was abolished by the specific CB1 receptor antagonist SR141716A. The stimulation of 45Ca(2+)-uptake by DALN was resistant to pertussis toxin (PTX), suggesting that Gi/Go GTP-binding proteins did not mediate this effect. Furthermore, PTX unmasked a stimulatory effect of a high concentration of DALN (1 microM), which by itself failed to stimulate calcium uptake in naive cells. The stimulatory effect of DALN on calcium entry to the cells was blocked by nicardipine but not by omega-conotoxin GVIA, indicating the entry of calcium through L-type voltage-dependent calcium channels. Blocking cAMP-dependent protein kinase (PKA) by H-89 completely eliminated the elevation in calcium uptake, while blocking protein kinase C (PKC) by chelerythrine and calphostine-C only partially attenuated the stimulation. Blocking calmodulin by W-7 revealed a similar partial inhibition of the stimulatory effect of DALN. Hence, we suggest a cannabinoid-specific, PTX-insensitive, stimulatory effect on L-type voltage-dependent calcium channels, which is mediated by PKA and modulated by PKC and calmodulin. Topics: Adenylyl Cyclases; Analgesics; Animals; Calcium; Calcium Channels, L-Type; Calcium Signaling; Calmodulin; Cannabinoids; Central Nervous System; Cyclic AMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Enzyme Inhibitors; Humans; Membrane Potentials; Neuroblastoma; Pertussis Toxin; Phenanthridines; Piperidines; Protein Kinase C; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Rimonabant; Sodium Channels; Tumor Cells, Cultured; Virulence Factors, Bordetella | 2002 |
Endothelin-1 activates ET(A) receptors to increase intracellular calcium in model sensory neurons.
Endothelin-1 (ET-1) induces endothelin-A (ETA) receptor-mediated pain and selective excitation of nociceptors. Here we studied ET-1-induced changes in intracellular calcium (Ca2+in) in Fura-2 loaded mouse neuroblastoma-rat dorsal root ganglion hybrid cells (ND7/104). ET-1 (1-400 nM) induced concentration-dependent, transient increases in Ca2+in, probably of intracellular source. Responses to repeated application declined with increasing ET-1 concentration, implying receptor desensitization. Treatment of cells with the selective ETA receptor antagonist, BQ-123, produced a dose-dependent inhibition of the response that was 20% of ET-1 alone (IC50 = 20 nM, KI = 7 nM). No inhibition of the calcium response was observed with the selective ETB antagonist, BQ-788 (10-1000 nM). These results demonstrate that ET-1 induces dose- and ETA receptor-dependent release of Ca2+in in nociceptor-like neurons, and permit further examination of the pathways that underlie ET-1-induced pain signaling. Topics: Animals; Antihypertensive Agents; Calcium; Calcium Channels; Calcium Signaling; Cell Line, Transformed; Dose-Response Relationship, Drug; Endothelin Receptor Antagonists; Endothelin-1; Fluorescent Dyes; Fluorometry; Fura-2; Ganglia, Spinal; Intracellular Fluid; Mice; Models, Biological; Neuroblastoma; Neurons, Afferent; Nociceptors; Oligopeptides; Pain; Peptides, Cyclic; Piperidines; Rats; Receptor, Endothelin A; Receptors, Endothelin | 2001 |
Chronic ethanol increases the cannabinoid receptor agonist anandamide and its precursor N-arachidonoylphosphatidylethanolamine in SK-N-SH cells.
In an earlier study, we demonstrated that chronic ethanol (EtOH) exposure down-regulated the cannabinoid receptors (CB1) in mouse brain synaptic plasma membrane. In the present study, we investigated the effect of chronic EtOH on the formation of anandamide (AnNH), an endogenous cannabimimetic compound, and its precursor N-arachidonoylphosphatidylethanolamine (N-ArPE) in SK-N-SH cells that were prelabeled with [3H]arachidonic acid. The results indicate that exposure of SK-N-SH cells to EtOH (100 mM) for 72 h significantly increased levels of [3H]AnNH and [3H]N-ArPE (p < 0.05) (1.43-fold for [3H]AnNH and 1.65-fold for [3H]N-ArPE). Exposure of SK-N-SH cells to EtOH (100 mM, 24 h) inhibited initially the formation of [3H]AnNH at 24 h, followed by a progressive increase, reaching a statistical significance level at 72 h (p < 0.05). [3H]N-ArPE increased gradually to a statistically significant level after 48 and 72 h (p < 0.05). Incubation with exogenous ethanolamine (7 mM) and EtOH (100 mM, 72 h) did not result in an additive increase in the formation of [3H]AnNH. The formation of [3H]AnNH and [3H]N-ArPE by EtOH was enhanced by the Ca2+ ionophore A23187 or by the depolarizing agent veratridine and the K+ channel blocker 4-aminopyridine. Further, the EtOH-induced formation of [3H]AnNH and [3H]N-ArPE was inhibited by exogenous AnNH, whereas only [3H]AnNH formation was inhibited by the CB1 receptor antagonist SR141716A and pertussis toxin, suggesting that the CB1 receptor and G(i/o) protein mediated the regulation of AnNH levels. The observed increase in the levels of these lipids in SK-N-SH cells may be a mechanism for neuronal adaptation and may serve as a compensatory mechanism to counteract the continuous presence of EtOH. The present observation taken together with our previous results indicate the involvement of the endocannabinoid system in mediating some of the pharmacological actions of EtOH and may constitute part of a common brain pathway mediating reinforcement of drugs of abuse including EtOH. Topics: Arachidonic Acid; Arachidonic Acids; Binding, Competitive; Calcium; Cannabinoid Receptor Modulators; Cannabinoids; Cell Survival; Central Nervous System Depressants; Endocannabinoids; Ethanol; GTP-Binding Proteins; Humans; Neuroblastoma; Pertussis Toxin; Phosphatidylethanolamines; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Rimonabant; Tritium; Tumor Cells, Cultured; Virulence Factors, Bordetella | 1999 |
Binding of [3H]U-101958 to sigma1 receptor-like sites in human cerebellum and neuroblastoma cells.
1-Benzyl-4-[N-(3-isopropoxy-2-pyridinyl)-N-methyl]-amino-piperidine ([3H]U-101958), a dopamine D4 receptor ligand, was found to bind to a large sigma1 receptor-like component in human cerebellum and SK-N-MC neuroblastoma cells with high affinity (2-4 nM Kd). By contrast, binding to dopamine D4 receptors represented 10% or less of the sigma1 receptor-like site. Considering that U-101958 has been characterized as either a dopamine D4 receptor agonist or antagonist, depending on the system under study, the observation that U-101958 also binds to sigma1 receptor-like sites is important for accurate interpretation of the pharmacological actions of this compound. [3H]U-101958 may be a useful radioligand for sigma1 rather than dopamine D4 receptor sites. Topics: Aminopyridines; Binding, Competitive; Cerebellum; Culture Techniques; Dopamine Agents; Humans; Neuroblastoma; Piperidines; Radioligand Assay; Receptors, Dopamine D2; Receptors, Dopamine D4; Receptors, sigma; Reverse Transcriptase Polymerase Chain Reaction; Sigma-1 Receptor | 1999 |
BIRICODAR (VX-710; Incel): an effective chemosensitizer in neuroblastoma.
Clinical studies have suggested that both MDR1 and MRP may play a significant role in the chemosensitivity and outcome of neuroblastoma. To clarify the nature of multidrug resistance (MDR) in this tumour a series of six neuroblastoma cell lines have been characterized with regard to P-glycoprotein, MRP and LRP expression using immunocytochemistry and expression of MDR1, MRP, LRP and topoisomerase II genes using reverse transcription polymerase chain reaction (RT-PCR). By RT-PCR, all lines expressed MRP, five expressed LRP and four expressed MDR1, but protein levels of each of these were variable. Chemosensitization to a range of MDR-associated drugs (vincristine, doxorubicin, etoposide, taxotere, topotecan) and non-MDR-associated drugs (cisplatin, melphalan) by three modulating agents, cyclosporin A, PSC 833 and the novel Biricodar (VX-710; Incel), was evaluated using a colourimetric cytotoxicity assay (MTS). Alteration of daunorubicin efflux by these agents was evaluated using FACS analysis. Clonogenic assay was used to study the influence of these chemosensitizers on vincristine cytotoxicity. Marked sensitization to vincristine was observed in MDR1-positive lines, and a similar but less consistent effect was seen with taxotere, doxorubicin and etoposide. With MRP-positive, MDR-negative lines, only VX-710 caused consistent sensitization. These data confirm MDR1 and MRP expression as contributory factors in chemoresistance in neuroblastoma and indicate that VX-710 may be a useful modulator of both mechanisms and worthy of clinical evaluation in this tumour. Topics: Antigens, Neoplasm; Antineoplastic Agents, Phytogenic; ATP Binding Cassette Transporter, Subfamily B, Member 1; DNA Topoisomerases, Type II; DNA-Binding Proteins; Drug Interactions; Drug Resistance, Multiple; Humans; Isoenzymes; Neuroblastoma; Piperidines; Pyridines; Reverse Transcriptase Polymerase Chain Reaction; Ribosomal Proteins; Tumor Cells, Cultured; Tumor Stem Cell Assay; Vincristine | 1999 |
D4 dopamine receptor-mediated phospholipid methylation and its implications for mental illnesses such as schizophrenia.
Previous studies have shown D2-like dopamine receptor involvement in the regulation of phospholipid methylation (PLM), while others have documented impaired methionine and folate metabolism in schizophrenia. Utilizing [14C]formate labeling in cultured neuroblastoma cell lines, we now show that D4 dopamine receptors (D4R) mediate the stimulatory effect of dopamine (DA) on PLM. The effect of DA was potently blocked by highly D4R-selective antagonists and stimulated by the D4R-selective agonist CP-226269. DA-stimulated PLM was dependent upon the activity of methionine cycle enzymes, but DA failed to increase PLM in [3H]methionine labeling studies, indicating that a methionine residue in the D4R might be involved in mediating PLM. A direct role for MET313, located on transmembrane helix No. 6 immediately adjacent to phospholipid headgroups, was further suggested from adenosylation, site-directed mutagenesis and GTP-binding results. A comparison of PLM in lymphocytes from schizophrenia patients vs control samples showed a four-fold lower activity in the schizophrenia group. These findings reveal a novel mechanism by which the D4R can regulate membrane composition. Abnormalities in D4R-mediated PLM may be important in psychiatric illnesses such as schizophrenia. Topics: Amino Acid Sequence; Aminopyridines; Animals; Benzazepines; Binding Sites; Carbon Radioisotopes; CHO Cells; Clozapine; Cricetinae; Dopamine Agonists; Dopamine Antagonists; Dopamine D2 Receptor Antagonists; Formates; Guanosine 5'-O-(3-Thiotriphosphate); Humans; Methionine; Mutagenesis, Site-Directed; Neuroblastoma; Phospholipids; Phosphorylation; Piperidines; Psychotic Disorders; Pyridines; Pyrroles; Raclopride; Receptors, Dopamine D2; Receptors, Dopamine D4; Recombinant Proteins; S-Adenosylmethionine; Salicylamides; Schizophrenia; Transfection; Tumor Cells, Cultured | 1999 |
Separation of M-like current and ERG current in NG108-15 cells.
Differentiated NG108-15 neuroblastoma x glioma hybrid cells were whole-cell voltage-clamped. Hyperpolarizing pulses, superimposed on a depolarized holding potential (-30 or -20 mV), elicited deactivation currents which consisted of two components, distinguishable by fitting with two exponential functions. Linopirdine [DuP 996, 3,3-bis(4-pyridinylmethyl)-1-phenylindolin-2-one), a neurotransmitter-release enhancer known as potent and selective blocker of the M-current of rat sympathetic neurons, in concentrations of 5 or 10 microM selectively inhibited the fast component (IC50 = 14.7 microM). The slow component was less sensitive to linopirdine (IC50>20 microM). The class III antiarrhythmics [(4-methylsulphonyl)amido]benzenesulphonamide (WAY-123.398) and 1-[2-(6-methyl-2-pyrydinil)ethyl]-4-(4-methylsulphonylaminobenz oyl) piperidine (E-4031), selective inhibitors of the inwardly rectifying ERG (ether-à-go-go-related gene) potassium channel, inhibited predominantly the slow component (IC50 = 38 nM for E-4031). The time constant of the WAY-123.398-sensitive current resembled the time constant of the slow component in size and voltage dependence. Inwardly rectifying ERG currents, recorded in K+ -rich bath at strongly negative pulse potentials, resembled the slow component of the deactivation current in their low sensitivity to linopirdine (28% inhibition at 50 microM). The size of the slow component varied greatly between cells. Accordingly, varied the effect of WAY-123.398 on deactivation current and holding current. RNA transcripts for the following members of the ether-à-go-go gene (EAG) K+ channel family were found in differentiated NG108-15 cells: ERG1, ERG2, EAGI, EAG-like (ELK)1, ELK2; ERG3 was only present in non-differentiated cells. In addition, RNA transcripts for KCNQ2 and KCNQ3 were found in differentiated and non-differentiated cells. We conclude that the fast component of the deactivation current is M-like current and the slow component is deactivating ERG current. The molecular correlates are probably KCNQ2/KCNQ3 and ERG1/ERG2, respectively. Topics: Animals; Benzimidazoles; Bradykinin; Cation Transport Proteins; Ether-A-Go-Go Potassium Channels; Indoles; KCNQ2 Potassium Channel; KCNQ3 Potassium Channel; Membrane Transport Proteins; Mice; Neuroblastoma; Piperidines; Potassium Channels; Potassium Channels, Voltage-Gated; Pyridines; Rats; Sulfanilamides; Sympathetic Nervous System; Tumor Cells, Cultured | 1999 |
Inactivation of the ERG current in NG108-15 cells.
Differentiated NG108-15 neuroblastoma x glioma hybrid cells were whole-cell voltage clamped. The rate of inactivation of ERG (ether-à-go-go related gene) potassium channels was measured with a three-pulse protocol. Contamination with delayed rectifier current at positive potentials was avoided by using the selective ERG channel blocker E-4031. The curve relating time constant of inactivation tau to membrane potential V could be fitted by a Gauss curve. In a bath with 40 mM K(+), the curve peaked at V = -36 mV. Lowering [K(+)](o) decreased tau. At V = -20 mV, the average tau was 25.4 ms in 40 mM K(+), 20.6 ms in 6.5 mM K(+), and 15.0 ms in 0 mM K(+). This resembles the relation between tau and [K(+)](o) in ERG channels expressed in Xenopus oocytes. Topics: Animals; Electric Conductivity; Glioma; Hybrid Cells; Ion Channel Gating; Mice; Neuroblastoma; Normal Distribution; Patch-Clamp Techniques; Piperidines; Potassium Channel Blockers; Potassium Channels; Pyridines; Rats; Tumor Cells, Cultured | 1999 |
Regulation of delta opioid receptors by delta9-tetrahydrocannabinol in NG108-15 hybrid cells.
In this study we employed the neuroblastoma x glioma NG 108-15 cell line as a model for investigating the effects of long-term activation of cannabinoid receptors on delta opioid receptor desensitization, down-regulation and gene expression. Exposure of NG 108-15 cells to (-)-delta9-tetrahydrocannabinol (delta9-THC) reduced opioid receptor binding, evaluated in intact cells, by approximately 40-45% in cells exposed for 24 h to 50 and 100 nM delta9-THC and by approximately 25% in cells exposed to 10 nM delta9-THC. Lower doses of delta9-THC (0.1 and 1 nM) or a shorter exposure time to the cannabinoid (6 h) were not effective. Down-regulation of 6 opioid receptors was not observed in cells exposed for 24 h to pertussis toxin (PTX) and then treated for 24 h with 100 nM delta9-THC. In cells that were exposed for 24 h to the cannabinoid, the ability of delta9-THC and of the delta opioid receptor agonist [D-Ser2, Leu5, Thr6]enkephalin to inhibit forskolin-stimulated cAMP accumulation was significantly attenuated. Prolonged exposure of NG 108-15 cells to 100 nM delta9-THC produced a significant elevation of steady-state levels of delta opioid receptor mRNA. This effect was not observed in cells pretreated with PTX. The selective cannabinoid receptor antagonist SR 141716A blocked the effects elicited by delta9-THC on delta opioid receptor desensitization, down-regulation and gene expression; thus indicating that these are mediated via activation of cannabinoid receptors. These data demonstrate the existence, in NG 108-15 cells, of a complex cross-talk between the cannabinoid and opioid receptors on prolonged exposure to delta9-THC triggered by changes in signaling through Gi and/or G0-coupled receptors. Topics: Animals; Colforsin; Dose-Response Relationship, Drug; Dronabinol; Enkephalin, Leucine; Glioma; Mice; Neuroblastoma; Piperidines; Pyrazoles; Rats; Receptors, Opioid, delta; Rimonabant; RNA, Messenger; Tumor Cells, Cultured | 1998 |
Sulfonylureas blockade of neural and cardiac HERG channels.
The human ether-a-go-go-related gene (herg) encodes a K+ current (I(HERG)) which plays a fundamental role in heart excitability and in neurons by contributing to action potential repolarization and to spike-frequency adaptation, respectively. In this paper we show that I(HERG), recorded in neuroblastoma cells and guinea-pig ventricular myocytes, was reversibly inhibited by the K(ATP) channel blocker glibenclamide (IC50 = 74 microM). The voltage and use dependence of glibenclamide blockade were also evaluated. Another sulfonylurea, glimepiride, had less effective results in blocking I(HERG). The findings of this study are relevant to the interpretation of glibenclamide effects on cellular electrophysiology and suggest that oral antidiabetic therapy with sulfonylureas may contribute to iatrogenic QT prolongation and related arrhythmias. Topics: Action Potentials; Animals; Cation Transport Proteins; Chromans; DNA-Binding Proteins; Dose-Response Relationship, Drug; ERG1 Potassium Channel; Ether-A-Go-Go Potassium Channels; Glyburide; Guinea Pigs; Humans; Inhibitory Concentration 50; Mice; Myocardium; Neuroblastoma; Neurons; Nisoldipine; Piperidines; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Voltage-Gated; Pyridines; Rats; Sulfonamides; Sulfonylurea Compounds; Trans-Activators; Transcriptional Regulator ERG; Tumor Cells, Cultured | 1998 |
Isolation and expression of a mouse CB1 cannabinoid receptor gene. Comparison of binding properties with those of native CB1 receptors in mouse brain and N18TG2 neuroblastoma cells.
The predominant animal model in which the pharmacology of cannabinoids is studied is the mouse. Nonetheless, the structure and functional expression of the mouse cannabinoid receptor (CB1) gene have not been reported. We have cloned and expressed the gene for the mouse CB1 receptor and compared its properties with those of native mouse CB1 receptors in brain and N18TG2 neuroblastoma cells. The mouse CB1 gene was isolated from a mouse 129 strain genomic library. Sequence analysis of a 6-kb BamHI fragment of the mouse CB1 genomic clone indicates 95% nucleic acid identity between mouse and rat (99.5% amino acid identity) and 90% nucleic acid identity (97% amino acid identity) between mouse and human. Examination of the 5' untranslated sequence of the mouse CB1 genomic clone revealed a splice junction site approximately 60 bp upstream from the translation start site, indicating the possibility of splice variants of the CB1 receptors. The coding region of the mouse CB1 receptor was stably expressed in 293 cells, and binding by [3H]SR 141716A and [3H]CP-55,940 was determined. The Bmax and Kd values obtained with [3H]SR 141716A (921 +/- 58 fmol/mg and 0.73 +/- 0.13 nM, respectively) were similar to those of native mouse CB1 receptors in brain (Bmax of 1.81 +/- 0.44 pmol/mg, Kd of 0.16 +/- 0.01 nM) and N18TG2 cells (Bmax of 197 +/- 29 fmol/mg, Kd of 0.182 +/- 0.08 nM). The mouse CB1 receptor genomic clone will be a useful tool for studying the function and regulation of the CB1 receptor in mice. Topics: Animals; Base Sequence; Binding Sites; Brain; Humans; Mice; Molecular Sequence Data; Neuroblastoma; Piperidines; Pyrazoles; Rats; Receptors, Cannabinoid; Receptors, Drug; Rimonabant; Structure-Activity Relationship; Tumor Cells, Cultured | 1997 |
Inhibition of M3 muscarinic acetylcholine receptor-mediated Ca2+ influx and intracellular Ca2+ mobilization in neuroblastoma cells by the Ca2+/calmodulin-dependent protein kinase inhibitor 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-trosyl]-4-phenylpipe
The role of Ca2+/calmodulin-dependent protein kinase (CaM kinase; EC 2.7.1.123) in the generation of Ca2+ signals by muscarinic acetylcholine receptors (mAChR) was studied. Changes in intracellular Ca2+ concentrations ([Ca2+]i) induced by mAChR activation were monitored in SK-N-SH human neuroblastoma cells using the dye Fura-2. SK-N-SH cells express M3 mAChR, as well as CaM kinase types II and IV, which are specifically inhibited by the CaM kinase antagonist KN-62 (1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazi ne). Carbamylcholine (100 microM) elicited an initial transient peak in [Ca2+]i due to mobilization of Ca2+ from internal stores, followed by a sustained elevation in [Ca2+]i that depended on the influx of extracellular Ca2+ and which was inhibited by EGTA and Ni2+. These mAChR-induced Ca2+ signals were diminished to an equal extent by preincubating the cells with 0.01 to 100 microM KN-62. KN-62 inhibited mAChR-induced Ca2+ influx and mobilization from internal stores by about 25-30%, producing a half-maximal effect at approximately 1 microM. In contrast, KN-62 (25 microM) almost completely abolished carbamylcholine-stimulated entry of divalent cations through Mn2+-permeant channels, as revealed by Mn2+ quenching of Fura-2 fluorescence. KN-62 also almost completely abolished Ca2+ influx induced by depolarization of the cells with 25 mM K+ (IC50 = 3 microM). These results suggest that CaM kinases regulate both the mobilization of intracellular Ca2+ and the stimulation of Ca2+ influx that are induced by mAChR activation, and indicate that the mAChR-induced influx of Ca2+ occurs through Ca2+ channels other than, or in addition to, the voltage-gated calcium channels or Mn2+-permeant channels which are inhibited by KN-62. Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Calcium; Calcium-Calmodulin-Dependent Protein Kinases; Carbachol; Enzyme Inhibitors; Humans; Neuroblastoma; Piperidines; Receptor, Muscarinic M3; Receptors, Muscarinic; Signal Transduction; Tumor Cells, Cultured | 1997 |
A HERG-like K+ channel in rat F-11 DRG cell line: pharmacological identification and biophysical characterization.
1. The relationships between the K+ inward rectifier current present in neuroblastoma cells (IIR) and the current encoded by the human ether-á-go-go-related gene (HERG), IHERG, and the rapidly activating repolarizing cardiac current IK(r), were investigated in a rat dorsal root ganglion (DRG) x mouse neuroblastoma hybrid cell line (F-11) using pharmacological and biophysical treatments. 2. IIR shared the pharmacological features described for IK(r), including the sensitivity to the antiarrhythmic drugs E4301 and WAY-123,398, whilst responding to Cs+, Ba2+ and La3+ in a similar way to IHERG. 3. The voltage-dependent gating properties of IIR were similar to those of IK(r) and IHERG, although IIR outward currents were negligible in comparison. 4. In high K+ extracellular solutions devoid of divalent cations, IIR deactivation kinetics were removed resulting in long-lasting currents apparently activated in hyperpolarization, with a marked (2.7-fold) increase in conductance, as recorded from the instantaneous linear current-voltage relationship at -120 mV. Re-addition of Ca2+ restored the original closure of the channel whereas re-addition of Mg2+ reduced the peak current. 5. The IIR described here, the heart IK(r) and the IHERG could be successfully predicted by a unique kinetic model where the voltage dependencies of the activation/inactivation gates were properly voltage shifted. On the whole, IIR seems to be the first example of a HERG-type current constitutively expressed and operating in mammalian cells of the neuronal lineage. Topics: Animals; Anti-Arrhythmia Agents; Benzimidazoles; Brain Neoplasms; Cation Transport Proteins; Cations, Divalent; DNA-Binding Proteins; Electrophysiology; ERG1 Potassium Channel; Ether-A-Go-Go Potassium Channels; Ganglia, Spinal; Hybrid Cells; Ion Channel Gating; Kinetics; Membrane Potentials; Mice; Models, Biological; Neuroblastoma; Patch-Clamp Techniques; Piperidines; Potassium Channels; Potassium Channels, Voltage-Gated; Pyridines; Rats; Sulfanilamides; Trans-Activators | 1996 |
2-Arachidonoylglycerol, a putative endogenous cannabinoid receptor ligand, induces rapid, transient elevation of intracellular free Ca2+ in neuroblastoma x glioma hybrid NG108-15 cells.
Low concentrations of 2-arachidonoylglycerol were found to induce rapid, transient elevation of intracellular free Ca2+ in NG108-15 cells (EC50 was 150 nM). Free arachidonic acid, 2-palmitoylglycerol, 2-oleoylglycerol, 2-linoleoylglycerol and 2-docosahexaenoylglycerol were inactive. Anandamide acted as a partial agonist. Importantly, desensitization was observed upon sequential challenge with 2-arachidonoylglycerol. Furthermore, cross-desensitization was observed between 2-arachidonoylglycerol and WIN 55212-2, a cannabinoid receptor agonist. Pretreatment of the cells with SR141716A, a cannabinoid receptor antagonist, abolished the activities of both 2-arachidonoylglycerol and WIN 55212-2. These results strongly suggest that 2-arachidonoylglycerol and WIN 55212-2 bind to a common cannabinoid receptor to elicit cellular responses and that 2-arachidonoylglycerol has some physiological role in nervous tissues. Topics: Arachidonic Acids; Benzoxazines; Calcium; Cannabinoids; Dose-Response Relationship, Drug; Drug Interactions; Endocannabinoids; Glioma; Glycerides; Hybrid Cells; Ligands; Morpholines; Naphthalenes; Neuroblastoma; Neurons; Piperidines; Platelet Activating Factor; Polyunsaturated Alkamides; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Rimonabant | 1996 |
Pharmacological evidence for neurokinin receptors in murine neuroblastoma C1300 cells.
We found that neurokinin A (NKA) and neurokinin B (NKB) induce an increase in the concentration of intracellular free Ca2+ ([Ca2+]i) in murine neuroblastoma C1300 cells (EC50: NKA 87 +/- 13 nM, NKB 97 +/- 15 nM). Substance P (SP) also caused a transient Ca2+ increase, although the potency of SP was much less than that of NKA and NKB. The increase in [Ca2+]i induced by NKA and NKB was inhibited by SR 48,968, a selective antagonist for NK2, and [beta Ala8]NKA(4-10), a selective agonist for NK2, did not stimulate the increase in [Ca2+]i. NKA- and NKB-induced Ca2+ mobilization was not inhibited by CP-96,345 and [Trp7, beta Ala8]NKA(4-10), selective antagonists for NK1 and NK3, respectively. These results suggested that C1300 cells express endogenous NK2 neurokinin receptors that have different features from known NK2 receptors. Topics: Animals; Benzamides; Calcium; Cell Line; Kinetics; Mice; Neuroblastoma; Neurokinin A; Neurokinin B; Piperidines; Receptors, Tachykinin; Substance P; Tumor Cells, Cultured | 1995 |
Inhibition of N-type Ca2+ channel currents in human neuroblastoma (SH-SY5Y) cells by muscarine via stimulation of M3 receptors.
The effects of muscarine on whole-cell Ca2+ channel currents in SH-SY5Y cells were studied using conventional and perforated-patch-clamp techniques, with 10 mM Ba2+ as charge carrier. Muscarine (10-300 microM) caused concentration-dependent inhibitions of Ca2+ channel currents which were only reversible when perforated-patch recordings were used. Inhibition of currents was associated with slowing of activation kinetics in approximately 50% of cells. In the presence of 5 microM nifedipine, muscarine was still able to inhibit currents, but after pre-exposure of cells to 1 microM omega-conotoxin GVIA the inhibitory effects of muscarine were almost completely lost. In the presence of 100 microM muscarine, Bay K 8644 (5 microM) was still able to enhance current amplitudes. Pre-treatment of cells with pertussis toxin (250 ng/ml for 16-24 hr) or inclusion of 1 mM GDP-beta-S in the patch-pipette prevented the inhibitory actions of muscarine. Hexahydrosiladifenidol (0.1-1 microM) antagonized the actions of muscarine (calculated pA2 7.1) but the presence of 10 microM pirenzipine or 0.1 microM methoctramine in the bath solution did not alter the degree of current inhibition caused by 100 microM muscarine. In summary, these results indicate that muscarine in SH-SY5Y cells causes inhibition of N-type Ca2+ channels via a M3 receptor coupled to a pertussis toxin-sensitive G-protein. Topics: Brain Neoplasms; Calcium Channel Blockers; GTP-Binding Proteins; Humans; Muscarine; Muscarinic Agonists; Neuroblastoma; Parasympatholytics; Patch-Clamp Techniques; Pertussis Toxin; Piperidines; Receptors, Muscarinic; Tumor Cells, Cultured; Virulence Factors, Bordetella | 1995 |
5-HT3 receptor antagonism by anpirtoline, a mixed 5-HT1 receptor agonist/5-HT3 receptor antagonist.
1. The aim of this study was to provide evidence that anpirtoline, which is an agonist at 5-HT1B and 5-HT1D receptors and also displays submicromolar affinity for 5-HT1A recognition sites, in addition, acts as an antagonist at 5-HT3 receptors. 2. In radioligand binding studies on rat brain cortical membranes, anpirtoline inhibited specific binding of [3H]-(S)-zacopride to 5-HT3 receptor recognition sites (pKi: 7.53). 3. In N1E-115 neuroblastoma cells in which [14C]-guanidinium was used as a tool to measure cation influx through the 5-HT3 receptor channel, the 5-HT-induced influx was concentration-dependently inhibited by anpirtoline. In this respect, anpirtoline mimicked other 5-HT3 receptor antagonists; the rank order of potency was ondansetron > anpirtoline > metoclopramide. 4. The concentration-response curve for 5-HT as a stimulator of [14C]-guanidinium influx was shifted to the right by anpirtoline (apparent pA2: 7.78). 5. In urethane-anaesthetized rats, anpirtoline inhibited (at lower potency than zacopride and tropisetron) the 5-HT- or phenylbiguanide-induced bradycardia (Bezold-Jarisch reflex), but did not induce this reflex by itself. 6. Intravenous infusion of cisplatin in the domestic pig caused a consistent emetic response which was antagonized by anpirtoline. 7. It is concluded that anpirtoline, which was previously characterized as a 5-HT1 receptor agonist also proved to be a 5-HT3 receptor antagonist in several experimental models and, hence, exhibits a unique pattern of properties at different 5-HT receptors. Topics: Animals; Antidepressive Agents; Antiemetics; Brain Neoplasms; Cisplatin; Entorhinal Cortex; In Vitro Techniques; Male; Mice; Neuroblastoma; Piperidines; Pyridines; Radioligand Assay; Rats; Rats, Sprague-Dawley; Reflex; Serotonin; Serotonin Antagonists; Serotonin Receptor Agonists; Swine; Tumor Cells, Cultured | 1995 |
[3H]BIMU-1, a 5-hydroxytryptamine3 receptor ligand in NG-108 cells, selectively labels sigma-2 binding sites in guinea pig hippocampus.
The binding of [3H]endo-N-(8-methyl-8-azabicyclo[3.2.1.]oct-3-yl)- 2,3-dihydro-3-ethyl-2-oxo-1H-benzimidazole-1-carboxamide hydrochloride ([3H]BIMU-1) a benzimidazolone with high affinity for 5-hydroxytryptamine (5-HT)3 and 4 5-HT3 and 5-HT4 receptors, was characterized in NG-108 cells and guinea pig hippocampus. Specific, heat-sensitive, binding of [3H]BIMU-1 was detected in both NG-108 cells and guinea pig hippocampus. In NG-108 cell membranes, a portion of the specific binding was displaced by 5-HT3 receptor ligands with affinities and specificity consistent with the labeling of 5-HT3 receptors. The residual specific binding was insensitive to serotonin (Ki > 1 mM) but was displaced by haloperidol (Ki of 50 nM). In guinea pig hippocampal membranes [3H]BIMU-1 binding was insensitive to serotonin but was displaced by haloperidol, and 1,3-di-o-tolyl-guanidine with affinities appropriate for the labeling of a sigma binding site (Ki of 6.3 and 31 nM, respectively). The affinity profile of ligands displacing [3H] BIMU-1 binding in guinea pig hippocampus was consistent with the selective labeling of a sigma-2 binding site because the sigma-1 selective benzomorphans, (+)-pentazocine and (+)-N-allylnormetazocine, only weakly displaced the binding (Ki greater than 1 microM). The affinity of BIMU-1 for sigma-2 binding sites (Ki = 32 nM) was 200-fold greater than that for sigma-1 binding sites (Ki = 6.3 microM), dopamine (D1 and D2), other serotonin (5-HT1A, 5-HT2A, 5-HT2C) and muscarinic (M1, M2, M3 and M4) receptors (Ki > 10 microM). The distribution of haloperidol-sensitive [3H]BIMU-1 binding was also consistent with the labeling of sigma-2 binding sites. These data suggest that [3H]BIMU-1 selectively labels sigma-2 binding sites in guinea pig hippocampus. [3H]BIMU-1, under appropriate experimental conditions, is thus the first sigma-2 binding site radioligand to be characterized. Topics: Animals; Autoradiography; Benzimidazoles; Binding Sites; Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Guinea Pigs; Hippocampus; Male; Membranes; Mice; Neuroblastoma; Piperidines; Rats; Receptors, Serotonin; Receptors, sigma; Sensitivity and Specificity; Tritium; Tumor Cells, Cultured | 1993 |
Comparison of pyrrolidinyl and piperidinyl benzamides for their anticonvulsant activity and inhibitory action on sodium channel.
1. A pair of benzamide analogues containing a pyrrolidinyl or piperidinyl group was examined for their anticonvulsant activity against the electroshock-induced seizures in mice and the ability to block the voltage-gated Na channel in N1E-115 cells, in comparison with the prototype compound, U-54494A, (+/-)-cis-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-ben zam ide , a potent anticonvulsant and a Na channel blocker. 2. The pyrrolidinyl benzamide (U-49524E) was found to be effective against the electroshock-induced seizures (ED50 = 35 mg kg-1, i.p.) whereas the benzamide with a piperidinyl moiety (U-49132E) was inactive (ED50 greater than 100 mg kg-1). 3. Using whole-cell patch clamp techniques we found that U-49132E was several times less potent, with an IC50 of 396 microM as compared to 118 microM for U-49524E at the holding potential of -80 mV, and was much slower in blocking Na channels with a half-time of 10.7 +/- 1.1 min vs. 2.2 +/- 0.4 min for its counterpart. 4. Qualitatively, their general modes of interaction with Na channels were similar to each other and to that of U-54494A in that they interacted with the resting and slowly-inactivated states of the channels and exhibited a use-dependent inhibition because of a slow recovery from the inactivated state in the presence of the drugs. 5. Comparison of their physicochemical properties, shows the less potent and slowly acting U-49132E is more hydrophobic and bulkier than U-49524E, but has the same pKa. This suggests that the drugs approach the Na channel through a narrow and hydrophilic pathway.6. Overall, this study underscores the importance of inhibiting the Na channel to the anticonvulsant activity of the benzamide compounds. Topics: Animals; Anticonvulsants; Cyclohexanes; Injections, Intraperitoneal; Male; Mice; Neuroblastoma; Piperidines; Pyrrolidines; Seizures; Sodium; Sodium Channels; Tumor Cells, Cultured | 1992 |
Muscarinic receptor subtypes in human neuroblastoma cell lines SH-SY5Y and IMR-32 as determined by receptor binding, Ca++ mobilization and northern blotting.
Muscarinic receptor subtypes in neuroblastoma cell lines IMR-32 and SH-SY5Y were determined with receptor binding, Ca++ mobilization and Northern blotting. Displacement of [3H]NMS with pirenzepine in IMR-32 cells revealed apparent binding sites with Kd values of 5 (41%) and 237 nM (59%). With 4-diphenylacetoxy-N-metylpiperidine metiodid, a similar proportion of apparent high- and low-affinity binding was obtained: 36 (Kd = 0.26 nM) and 64% (Kd = 6.3 nM), respectively. In SH-SY5Y cells, two different affinities with apparent Kd of 40 (24%) and 460 nM (76%) could be distinguished with pirenzepine, even though the Kd of the apparent high-affinity site varied markedly (variation = 8.7-96.8 nM). Inhibition of carbachol-induced Ca++ mobilization displayed high sensitivity to 4-diphenylacetoxy-N-methylpiperidine metiodid in both cell lines. IMR-32 cells displayed high sensitivity to pirenzepine, whereas the sensitivity varied between different batches of SH-SY5Y cells. DNA fragments (approximately 1000 base pairs) from SH-SY5Y DNA amplified with polymerase chain reaction were used as probes for muscarinic receptor mRNA. Northern blotting with the Hm1-specific probe gave a stronger signal for SH-SY5Y than for IMR-32, whereas the result obtained with the Hm2-probe was the opposite. Also, the Hm3 mRNA was detected in SH-SY5Y cells. The Hm4 and Hm5 transcripts were not detected in either of these cell lines. Topics: Blotting, Northern; Calcium; Humans; N-Methylscopolamine; Neuroblastoma; Phosphatidylinositols; Piperidines; Pirenzepine; Radioligand Assay; Receptors, Muscarinic; RNA, Messenger; Scopolamine Derivatives; Tumor Cells, Cultured | 1992 |
Sabeluzole, a memory-enhancing molecule, increases fast axonal transport in neuronal cell cultures.
Morphological rearrangements, such as synapse number changes, have been observed in the adult mammalian brain after various experimental paradigms of learning and behavioral experience. The role of axonal transport in the physical translocation of material during this form of brain plasticity has not been fully appreciated. We show here by quantitative video microscopy that sabeluzole (R58735), a new memory-enhancing drug in humans, effectively increases fast axonal transport in rat neuronal cell cultures. Long-term incubation (24 hr) with sabeluzole in the concentration range between 0.1 and 1 microM increases both velocity and jump length of saltatory movements maximally by 20-30% in embryonic hippocampal neurons. Acute treatment only increases the velocity by 15-20%. Furthermore, the inhibition of axonal transport by 0.1 mM vanadate in N4 neuroblastoma cells is reversed by 1 microM sabeluzole. Observations on the kinesin-induced microtubule mobility in a reconstituted system show a 10% enhancement by sabeluzole at an optimal concentration of 2 microM, but no increase in kinesin ATPase activity. To our knowledge, this is the first pharmacological compound shown to increase fast axonal transport. The mechanism of fast axonal transport enhancement is discussed as a rationale for new therapeutic treatment in neuropathology. Topics: Animals; Axonal Transport; Cell Line; Cells, Cultured; Embryo, Mammalian; Hippocampus; Kinesins; Memory; Microtubules; Neurites; Neuroblastoma; Neurons; Piperidines; Rats; Thiazoles | 1992 |
Stereoselective interaction of procyclidine, hexahydro-difenidol, hexbutinol and oxyphencyclimine, and of related antagonists, with four muscarinic receptors.
We investigated the binding properties of the (R)- and (S)-enantiomers of the muscarinic antagonists trihexyphenidyl, procyclidine, hexahydro-difenidol, p-fluoro-hexahydro-difenidol, hexbutinol, p-fluoro-hexbutinol, and their corresponding methiodides at muscarinic M1, M2, M3 and M4 receptor subtypes. In addition, binding properties of the (R)- and (S)-enantiomers of oxyphencyclimine were studied. The (R)- enantiomers (eutomers) of all the compounds had a greater affinity than the (S)-isomers for the four muscarinic receptor subtypes. The binding patterns of the (R)- and (S)-enantiomers were generally different. We did not observe any general correlation between the potency of the high-affinity enantiomer and the affinity ratio (eudismic ratio) of the two enantiomers. The results are discussed in terms of a 'four subsites' binding model. Topics: Alkynes; Animals; Corpus Striatum; Heart; Humans; In Vitro Techniques; Male; N-Methylscopolamine; Neuroblastoma; Pancreas; Parasympatholytics; Piperidines; Procyclidine; Pyrimidines; Rats; Rats, Inbred Strains; Receptors, Muscarinic; Scopolamine Derivatives; Stereoisomerism; Tritium | 1992 |
Apparent noncompetitive antagonism of muscarinic receptor mediated Ca2+ mobilization by some muscarinic antagonists.
Ca2+ mobilizations in SH-SY5Y and IMR-32 human neuroblastoma cell lines were measured using the fluorescent Ca2+ indicator fura-2. A variety of antagonists (atropine, pirenzepine, 4-DAMP and N-methyl-scopolamine) inhibited carbamyl choline-induced transient Ca2+ mobilization both in a competitive and a noncompetitive manner. The apparent noncompetitive inhibition constants were lower in IMR-32 than in SH-SY5Y cells even when the competitive inhibition constants were similar. This may relate to the previously reported differential expression of muscarinic receptor subtypes in these cell lines. Topics: Atropine; Calcium; Fura-2; Humans; Kinetics; Muscarinic Antagonists; N-Methylscopolamine; Neuroblastoma; Parasympatholytics; Piperidines; Pirenzepine; Receptors, Muscarinic; Scopolamine Derivatives; Spectrometry, Fluorescence; Tumor Cells, Cultured | 1992 |
Binding properties of nine 4-diphenyl-acetoxy-N-methyl-piperidine (4-DAMP) analogues to M1, M2, M3 and putative M4 muscarinic receptor subtypes.
1. We compared the binding properties of 4-diphenyl-acetoxy-N-methyl-piperidine methiodide (4-DAMP) and nine analogues of this compound on muscarinic receptors of human neuroblastoma NB-OK1 cells (M1 subtype), rat heart (M2 subtype), rat pancreas (M3 subtype) and to the putative M4 subtype in striatum. 2. The requirements for high affinity binding were somewhat different for the four receptor subtypes. In general, the requirements of M3 receptors were more stringent than for M1, M2 or putative M4 receptors. 3. The abilities of the compounds to discriminate muscarinic receptor subtypes were not correlated with their affinities at any subtype. 4. The temperature-dependence of binding of 4-DAMP analogues to M2 receptors varied with the drug structure. In particular, the increased affinity of the alpha-methyl derivative of 4-DAMP could be ascribed to van der Waals interactions. 5. The affinities of most 4-DAMP analogues for M2 and M3 receptors were similar to their pharmacological potencies on atrial and ileum preparations, respectively. 6. At concentrations above 1 microM, all 4-DAMP analogues as well as atropine, reduced the [3H]-N-methyl scopolamine ([3H]-NMS) dissociation rate from cardiac muscarinic receptors, with no obvious structure-activity relationship. Topics: Allosteric Regulation; Animals; Corpus Striatum; In Vitro Techniques; Male; Myocardium; N-Methylscopolamine; Neuroblastoma; Pancreas; Piperidines; Radioligand Assay; Rats; Rats, Inbred Strains; Receptors, Muscarinic; Scopolamine Derivatives; Structure-Activity Relationship; Temperature; Tumor Cells, Cultured | 1992 |
Study of the muscarinic receptor subtypes in N1E 115 mouse neuroblastoma cells.
Muscarinic receptors in N1E 115 mouse neuroblastoma cells were characterized by competition binding experiments using three agonists and five antagonists, including 4-DAMP and AF-DX 116, and by studying the effect of agonist stimulation on the cellular cAMP and cGMP content. The results of the binding studies with the antagonists suggest that only one single homogeneous binding site of the M1 muscarinic receptor subtype is present. For the binding with the agonists, two binding sites were detected, one with high affinity for the ligand (between 53 and 77% of the total binding sites depending on the agonist) and one with low affinity. In contrast to the results obtained with the binding experiments using antagonists, the study of the cellular cyclic nucleotide response upon carbachol stimulation suggested the presence of both the M1 and M2 subtypes as there was an increase in cyclic GMP concentration while at the same time, the prostaglandin-stimulated synthesis of cyclic AMP was inhibited. Considering both binding and functional data we suggest that in N1E 115 cells a majority of M1 and a minority of M2 muscarinic receptors are present; there is no evidence for the presence of M3 muscarinic receptors. Topics: Animals; Carbachol; Cyclic AMP; Cyclic GMP; Indicators and Reagents; Ligands; Mice; Neuroblastoma; Parasympatholytics; Piperidines; Pirenzepine; Quinuclidinyl Benzilate; Receptors, Muscarinic; Tumor Cells, Cultured | 1991 |
The human sigma site, which resembles that in NCB20 cells, may correspond to a low-affinity site in guinea pig brain.
1,3-di(2-[5-3H]tolyl)Guanidine ([3H]DTG) was found to bind to a single saturable population of binding sites in human cerebral cortex and NCB20 cells, a second low-affinity site was apparent in guinea pig brain. Displacement studies were performed to determine the pharmacology of the [3H]DTG binding site in these 3 membrane preparations. In human cortical tissue and NCB20 cell membranes the (+)-stereoisomers of benzomorphans displaced binding with Hill coefficients close to one, displayed similar affinity and did not give the biphasic displacement curve characteristic of guinea pig membranes. The pIC50 of the low-affinity component of the sigma binding site in guinea pig brain correlates best with the affinity of drugs for the binding site in human cortex. Topics: Animals; Brain Chemistry; Cells, Cultured; Cerebral Cortex; Cricetinae; Cricetulus; Dopamine Agents; Guanidines; Guinea Pigs; Humans; Kinetics; Male; Mice; Neuroblastoma; Pentazocine; Phenazocine; Piperidines; Radioligand Assay; Receptors, Opioid; Receptors, sigma; Stereoisomerism; Tumor Cells, Cultured | 1991 |
Characteristics of 5-HT3 binding sites in NG108-15, NCB-20 neuroblastoma cells and rat cerebral cortex using [3H]-quipazine and [3H]-GR65630 binding.
1. The biochemical and pharmacological properties of 5-HT3 receptors in homogenates of NG108-15 and NCB-20 neuroblastoma cells and rat cerebral cortex have been ascertained by the use of [3H]-quipazine and [3H]-GR65630 binding. 2. In NG108-15 and NCB-20 cell homogenates, [3H]-quipazine bound to a single class of high affinity (NG108-15: Kd = 6.2 +/- 1.1 nM, n = 4; NCB-20: Kd = 3.0 +/- 0.9 nM, n = 4; means +/- s.e.means) saturable (NG108-15: Bmax = 1340 +/- 220 fmol mg-1 protein; NCB-20: Bmax = 2300 +/- 200 fmol mg-1 protein) binding sites. In rat cortical homogenates, [3H]-quipazine bound to two populations of binding sites in the absence of the 5-hydroxytryptamine (5-HT) uptake inhibitor, paroxetine (Kd1 = 1.6 +/- 0.5 nM, Bmax1 = 75 +/- 14 fmol mg-1 protein; Kd2 = 500 +/- 300 nM, Bmax2 = 1840 +/- 1040 fmol mg-1 protein, n = 3), and to a single class of high affinity binding sites (Kd = 2.0 +/- 0.5 nM, n = 3; Bmax = 73 +/- 6 fmol mg-1 protein) in the presence of paroxetine. The high affinity (nanomolar) component probably represented 5-HT3 binding sites and the low affinity component represented 5-HT uptake sites. 3. [3H]-paroxetine bound with high affinity (Kd = 0.02 +/- 0.003 nM, n = 3) to a site in rat cortical homogenates in a saturable (Bmax = 323 +/- 45 fmol mg-1 protein, n = 3) and reversible manner. Binding to this site was potently inhibited by 5-HT uptake blockers such as paroxetine and fluoxetine (pKi s = 8.6-9.9), while 5-HT3 receptor ligands exhibited only low affinity (pK; < 7). No detectable specific [3H]-paroxetine binding was observed in NG108-15 or NCB-20 cell homogenates. 4. [3H]-quipazine binding to homogenates of NG108-15, NCB-20 cells and rat cortex (in the presence of 0.1 microM paroxetine) exhibited similar pharmacological characteristics. 5-HT3 receptor antagonists competed for [3H]-quipazine binding with high nanomolar affinities in the three preparations and the rank order of affinity was: (S)-zacopride > quarternized ICS 205-930 2 granisetron > ondansetron > ICS 205-209 (R)-zacopride > quipazine > renzapride > MDL-72222 > butanopride > metoclopramide. 5. [3H]-GR65630 labelled a site in NCB-20 cell homogenates with an affinity (Kd = 0.7 + 0.1 nms n = 4) and density (B__ = 1800 + 1000 fmol mg- protein) comparable to that observed with [3H]-quipazine. Competition studies also indicated a good correlation between the pharmacology of 5-HT3 binding sites when [3H]-GR65630 and [3H]-quipazine were used in these cells. 6. In conclusion, Topics: Animals; Binding, Competitive; Cell Line; Cerebral Cortex; Imidazoles; Indoles; Kinetics; Ligands; Mice; Nervous System Neoplasms; Neuroblastoma; Paroxetine; Piperidines; Quipazine; Rats; Receptors, Serotonin; Serotonin Antagonists; Tumor Cells, Cultured | 1991 |
Electrophysiological and binding studies on intact NCB-20 cells suggest presence of a low affinity sigma receptor.
Whole cell voltage clamp studies were performed on NCB-20 cells to examine physiological responses to drugs possessing affinities for sigma receptors. Those drugs [haloperidol, alpha-(4-fluoro-phenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazinebutano l (BMY-14802), pentazocine, N-allylnormetazocine (SKF-10047), 3-(3-hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP), phencyclidine, 1-[1-(2-thienyl)cyclohexyl]piperidine (TCP), (+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclohepten-5,10-imine maleate (MK-801)] caused an apparent inward current, which was due to blockade of a tonic, outward potassium current. The rank order of drug potencies in producing this effect generally resembled the rank orders of sigma-receptor affinities for the drugs, except that a reverse stereoselectivity was observed for several drugs. [3H](+)-SKF-10047 labeled two sites in intact NCB-20 cells (Kd = 49 nM, Bmax = 1.0 pmol/mg protein and Kd = 9.6 microM, Bmax = 69 pmol/mg protein). The high affinity site was similar pharmacologically to the sigma receptor assayed in membrane fragments from NCB-20 cells. However, the low affinity site showed a slightly different profile, highlighted by a reverse stereoselectivity. The rank order of drug potencies was as follows at the low affinity site: haloperidol greater than BMY-14802 greater than (-)-pentazocine greater than (+)-pentazocine greater than (-)-SKF-10047 greater than (-)-3-PPP greater than (+)-SKF-10047 greater than (+)-3-PPP greater than phencyclidine greater than TCP greater than MK-801.(ABSTRACT TRUNCATED AT 250 WORDS) Topics: Animals; Cricetinae; Cricetulus; Hybrid Cells; Ligands; Mice; Neuroblastoma; Phenazocine; Piperidines; Potassium Channels; Receptors, Opioid; Receptors, sigma; Stereoisomerism; Tumor Cells, Cultured | 1991 |
Stereoselectivity of (R)- and (S)-hexahydro-difenidol binding to neuroblastoma M1, cardiac M2, pancreatic M3, and striatum M4 muscarinic receptors.
(R)-Hexahydro-difenidol has a higher affinity for M1 receptors in NB-OK 1 cells, pancreas M3 and striatum M4 receptors (pKi 7.9 to 8.3) than for cardiac M2 receptors (pKi 7.0). (S)-Hexahydro-difenidol, by contrast, is nonselective (pKi 5.8 to 6.1). Our goal in the present study was to evaluate the importance of the hydrophobic phenyl, and cyclohexyl rings of hexahydro-difenidol for the stereoselectivity and receptor selectivity of hexahydro-difenidol binding to the four muscarinic receptors. Our results indicated that replacement of the phenyl ring of hexahydro-difenidol by a cyclohexyl group (----dicyclidol) and of the cyclohexyl ring by a phenyl moiety (----difenidol) induced a large (4- to 80-fold) decrease in binding affinity for all muscarinic receptors. Difenidol had a significant preference for M1, M3, and M4 over M2 receptors; dicyclidol, by contrast, had a greater affinity for M1 and M4 than for M2 and M3 receptors. The binding free energy decrease due to replacement of the phenyl and the cyclohexyl groups of (R)-hexahydro-difenidol by, respectively, a cyclohexyl and a phenyl moiety was almost additive in the case of M4 (striatum) binding sites. In the case of the cardiac M2, pancreatic M3, or NB-OK 1 M1 receptors the respective binding free energies were not completely additive. These results suggest that the four (R)-hexahydro-difenidol "binding moieties" (phenyl, cyclohexyl, hydroxy, and protonated amino group) cannot simultaneously form optimal interactions with the M1, M2, and M3 muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS) Topics: Animals; Binding, Competitive; Corpus Striatum; Humans; Male; Myocardium; Neuroblastoma; Pancreas; Piperidines; Rats; Rats, Inbred Strains; Receptors, Muscarinic; Stereoisomerism | 1991 |
Hemicholinium-3 derivatives A-4 and A-5 alter choline metabolism in NB41A3 neuroblastoma cells.
A-4, A-5 and HC-3 are experimental bis tertiary and quaternary amines which have been shown to be potent inhibitors of the sodium-dependent, high affinity choline uptake system. When incubated with neuroblastoma cells, experimental compounds A-4, A-5 and HC-3 inhibit choline metabolism. Over a 24-hr incubation, A-4, A-5 and HC-3 produced a significant decrease in total choline accumulation, choline incorporation into phospholipid and free choline content. However, despite decreases in choline incorporation into phospholipid, no change occurred in content of phosphatidylcholine. Treatment of cells with A-4, A-5 and HC-3 resulted in an increase in the incorporation of S-adenosyl-methionine into phosphatidylcholine. However, the incorporation of ethanolamine or serine into phosphatidylcholine was not increased. Phosphatidylcholine turnover was decreased in cells treated with A-4 and A-5. A-4, A-5 and HC-3 produce significant decreases in choline metabolism; however, the cells are able to maintain membrane integrity by decreasing turnover of phosphatidylcholine and increasing phosphatidylcholine synthesis through the methylation pathway. These studies suggest that the biological effects of A-4 and A-5 are independent of membrane perturbations. Topics: Animals; Biphenyl Compounds; Choline; Ethanolamine; Ethanolamines; Mice; Neuroblastoma; Phosphatidylcholines; Phospholipids; Piperidines; S-Adenosylmethionine; Tumor Cells, Cultured | 1991 |
Pumiliotoxin alkaloids: a new class of sodium channel agents.
Pumiliotoxin B (PTX-B) and a variety of congeneric alkaloids and synthetic analogs stimulated sodium flux and phosphoinositide breakdown in guinea pig cerebral cortical synaptoneurosomes. The effects of PTX-B and active congeners and analogs on sodium flux in synaptoneurosomes were potentiated markedly by scorpion venom (Leiurus quinquestriatus). In neuroblastoma cells, PTX-B and active congeners had no effect on sodium flux unless synergized by alpha-scorpion toxin or scorpion venom. Certain inactive congeners, lacking hydroxyl groups in the 6-alkylidene side chain, inhibited sodium flux elicited by PTX-B, scorpion venom, or the sodium channel activator batrachotoxin. Such inhibition appeared different from inhibition by local anesthetics, since pumiliotoxins, unlike local anesthetics, had little or no effect on binding of [3H]batrachotoxinin A benzoate to sodium channels. Thus, it appears likely that some "inactive" congeners bind to the PTX-B binding site, but do not activate sodium channels. In the absence of scorpion venom the stimulation of phosphoinositide breakdown in synaptoneurosomes was consonant with the stimulatory effects of these compounds on sodium flux through voltage-dependent sodium channels. Topics: Alkaloids; Amphibian Venoms; Animals; Guinea Pigs; In Vitro Techniques; Indolizines; Neuroblastoma; Phosphatidylinositols; Piperidines; Scorpion Venoms; Sodium; Sodium Channels; Structure-Activity Relationship | 1990 |
Characterization of the effect of two 4-methyl piperidine derivatives of hemicholinium-3, A-4 and A-5, on choline transport.
A-4 and A-5 are tertiary and N-methyl quaternary 4-methylpiperidine analogs of hemicholinium-3 (HC-3). Previous work in this laboratory has shown A-4 and A-5 to be inhibitors of the sodium-dependent, high affinity choline uptake system (SDHACU). Their effects on choline transport were characterized further using neuroblastoma 41A3 cells. These cells rapidly take up choline through two separate mechanisms: a SDHACU system and a sodium-independent, low affinity uptake system (SILACU). A-4, A-5 and HC-3 decreased 5 microM choline transport in a dose-dependent fashion. The compounds were unable to decrease choline transport at 250 microM choline suggesting that they are inactive with respect to SILACU. All three compounds significantly increased the Km but not the Vmax for the SDHACU system, suggesting a competitive mechanism of inhibition. Ki values ranged from 18 to 25 microM for A-4, 20 to 26 microM for A-5 and 68 to 75 microM for HC-3. Dose-response curves for inhibition of choline transport by A-5 and HC-3 were not changed by a 24-hr pre-exposure of the cells to each inhibitor. However, after a 24-hr pre-exposure to A-4, a significantly different dose-response curve was obtained compared to the dose-response curve for A-4 in untreated cells. After a 24-hr pre-exposure, a 4-hr recovery period was sufficient to remove the effect of each compound. These data suggest that A-4 and A-5, like HC-3, inhibit the SDHACU, competitively and reversibly. Topics: Animals; Biological Transport; Biphenyl Compounds; Choline; Dose-Response Relationship, Drug; Mice; Neuroblastoma; Parasympatholytics; Piperidines; Sodium; Tumor Cells, Cultured | 1990 |
Inhibition of cyclic AMP formation in N1E-115 neuroblastoma cells is mediated by a non-cardiac M2 muscarinic receptor subtype.
The cardioselective muscarinic antagonist, AF-DX 116 [11[2-[(diethyl-amino)-methyl]-O-1-piperidinyl]-5,11-dihydro-6H-pyrido- [2,3-b][1,4]-benzodiazepine-6-one), was weak at blocking the M2 muscarinic receptor-mediated inhibition of cyclic adenosine monophosphate (cAMP) formation in mouse neuroblastoma cells (clone N1E-115). In contrast, the glandular-selective antagonists, hexahydro-sila-difenidol (HHSiD) and 4-diphenylacetoxy-N-methyl-piperidine methiodide (4-DAMP), were quite potent at inhibiting this response, being 14- and 318-fold more potent than AF-DX 116 in this regard, respectively. According to the rank order of potency of these two classes of antagonists, these data provide the first pharmacological evidence that inhibition of cAMP formation in a neuronal tissue is mediated by a non-cardiac M2 muscarinic receptor subtype. Topics: Animals; Binding, Competitive; Cyclic AMP; Mice; Muscarinic Antagonists; N-Methylscopolamine; Neuroblastoma; Piperidines; Receptors, Muscarinic; Scopolamine Derivatives; Tumor Cells, Cultured | 1989 |
Muscarinic receptor binding characteristics of a human neuroblastoma SK-N-SH and its clones SH-SY5Y and SH-EP1.
The present study examines the muscarinic receptor binding characteristics of parent human neuroblastoma (SK-N-SH) and its neuroblast (SH-SY5Y) and epithelial-like (SH-EP1) clones using [3H]methylscopolamine [( 3H]NMS). Specific [3H]NMS binding to intact SK-N-SH and SH-SY5Y cells was saturable with a Kd of 0.2 nM and Bmax of 100-150 fmol/mg protein. Specific [3H]NMS binding to whole cell preparations of SH-EP 1 could not be detected. Pharmacological analysis of the binding site both in whole cells and membranes of SK-N-SH are indicative of an homogeneous receptor population possessing low affinity for the M1-selective antagonist pirenzepine. The muscarinic receptors expressed by the neuroblast clone, SH-SY5Y were further characterized and shown to have the properties of an homogeneous M3 subtype with low affinity for the M1-selective antagonist pirenzepine and the M2-cardioselective AFDX-116 but high affinity for 4-diphenylacetoxy-N-methyl piperidine methiodide (4-DAMP). In conclusion the SH-SY5Y neuroblastoma should provide an important human neuronal cell model with which to define the regulation of post-receptor events driven by a single receptor population. Topics: Arecoline; Atropine; Carbachol; Cell Membrane; Humans; Neuroblastoma; Piperidines; Pirenzepine; Receptors, Muscarinic; Tumor Cells, Cultured | 1989 |
Pumiliotoxin B binds to a site on the voltage-dependent sodium channel that is allosterically coupled to other binding sites.
Pumiliotoxin B (PTX-B), an alkaloid that has cardiotonic and myotonic activity, increases sodium influx in guinea pig cerebral cortical synaptoneurosomes. In the presence of scorpion venom (Leiurus) or purified alpha-scorpion toxin, the PTX-B-induced sodium influx is enhanced severalfold. PTX-B alone has no effect on sodium flux in N18 neuroblastoma cells but, in the presence of alpha-scorpion toxin, stimulation of sodium influx by PTX-B reaches levels comparable to that attained with the sodium channel activator veratridine. In neuroblastoma LV9 cells, a variant mutant that lacks sodium channels, neither veratridine nor PTX-B induces sodium fluxes in either the presence or absence of alpha-scorpion toxin. In synaptoneurosomes and in N18 cells, the sodium influx induced by the combination of PTX-B and alpha-scorpion toxin is inhibited by tetrodotoxin and local anesthetics. PTX-B does not interact with two of the known toxin sites on the sodium channel, as evidenced by a lack of effect on binding of [3H]saxitoxin or [3H]batrachotoxinin A benzoate to brain synaptoneurosomes. Synergistic effects on sodium influx with alpha-scorpion toxin, beta-scorpion toxin, and brevetoxin indicate that PTX-B does not interact directly with three other toxin sites on the sodium channel. Thus, PTX-B appears to activate sodium influx by interacting with yet another site on the voltage-dependent sodium channel, a site that is coupled allosterically to sites for alpha-scorpion toxin, beta-scorpion toxin, and brevetoxin. Topics: Alkaloids; Allosteric Site; Anesthetics, Local; Animals; Binding Sites; Biological Transport; Cells, Cultured; Cerebral Cortex; Drug Interactions; Guinea Pigs; Indolizines; Ion Channels; Neuroblastoma; Piperidines; Sodium; Stimulation, Chemical; Synaptosomes; Toxins, Biological | 1988 |
Sigma receptors on NCB-20 hybrid neurotumor cells labeled with (+)[3H]SKF 10,047 and (+)[3H]3-PPP.
(+)[3H]SKF 10,047 and (+)[3H]3-PPP label a homogeneous population of sites in NCB-20 cell membranes that apparently represent benzomorphan specific binding sites previously reported for this cell line. Their drug specificity indicates that these sites are very similar to sigma receptor binding sites labeled in brain tissues by these ligands and do not represent PCP receptors. Topics: Animals; Brain; Cells, Cultured; Cricetinae; Cricetulus; Hybrid Cells; Kinetics; Neuroblastoma; Phenazocine; Phencyclidine; Piperidines; Receptors, Opioid; Receptors, Opioid, delta; Stereoisomerism | 1986 |
Differentiation between ligand trapping into intact cells and binding on muscarinic receptors.
Binding properties of [3H] dexetimide , L-quinuclidinyl[phenyl-4-3H] benzilate and [3H]methylscopolamine were compared with intact 108 CC 15 cells and membrane preparations of those. The ability of the three ligands to label specifically muscarinic receptors on membrane fractions was quite similar. By contrast, when performed with intact cells, [3H] dexetimide and L-quinuclidinyl [phenyl-4-3H]benzilate revealed higher nonspecific binding which was prevented by methylamine, suggesting a trapping of the ligands within the cells presumably in the lysosomes. To the contrary, such nonspecific 'binding' or trapping was not detectable when [3H]methylscopolamine was used as ligand, a fact which makes this ligand particularly appropriate for labelling cell surface muscarinic receptors. It is concluded that more caution is needed in binding studies when performed with intact cells; indeed, besides specific binding on receptor sites, [3H]ligand can be entrapped within the cell and can even sometimes give the illusion of specific binding. The use of lysosomal agents which do not interfere with specific receptors on membrane preparations should allow one, in most cases, to discard the possibility of a trapping phenomenon in intact cells. Topics: Animals; Biological Transport; Cell Line; Cell Membrane; Dexetimide; Glioma; Ligands; Lysosomes; N-Methylscopolamine; Neuroblastoma; Piperidines; Quinuclidines; Quinuclidinyl Benzilate; Receptors, Muscarinic; Scopolamine Derivatives | 1984 |
Reduction of nitroxide free radicals by biological materials.
Topics: Animals; Brachyura; Cell Membrane; Chemical Phenomena; Chemistry; Clone Cells; Cyclic N-Oxides; Cysteine; Electron Spin Resonance Spectroscopy; Erythrocytes; Free Radicals; Mice; Nephropidae; Neuroblastoma; Neurons; Oxidation-Reduction; Piperidines; Sulfhydryl Compounds; Sulfhydryl Reagents | 1972 |