TTX-Sensitive and -Resistant Na+ Currents, and mRNA for the TTX-Resistant rH1 Channel, Are Expressed in B104 Neuroblastoma Cells

1997 ◽  
Vol 77 (1) ◽  
pp. 236-246 ◽  
Author(s):  
Xiang Q. Gu ◽  
Sulayman Dib-Hajj ◽  
Marco A. Rizzo ◽  
Stephen G. Waxman

Gu, Xiang Q., Sulayman Dib-Hajj, Marco A. Rizzo, and Stephen G. Waxman. TTX-sensitive and -resistant Na+ currents, and mRNA for the TTX-resistant rH1 channel, are expressed in B104 neuroblastoma cells. J. Neurophysiol. 77: 236–246, 1997. To examine the molecular basis for membrane excitability in a neuroblastoma cell line, we used whole cell patch-clamp methods and reverse transcription-polymerase chain reaction (RT-PCR) to study Na+ currents and channels in B104 cells. We distinguished Tetrodotoxin (TTX)-sensitive and -resistant Na+ currents and detected the mRNA for the cardiac rH1 channel in B104 cells. Na+ currents could be recorded in 65% of cells. In the absence of TTX, mean peak Na+ current density was 126 ± 19 pA/pF, corresponding to a channel density of 2.7 ± 0.4/μ2 (mean ± SE). Time-to-peak (t-peak), activation (τm), and inactivation time constants (τh) for Na+ currents in B104 cells were 1.0 ± 0.04, 0.4 ± 0.06, and0.9 ± 0.04 ms at −10 mV. The peak conductance-voltage relationship had a V 1/2 of −39.8 ± 1.5 mV. V 1/2 for steady-state inactivation was −81.6 ± 1.5 mV. TTX-sensitive and -resistant components of the Na current had half-maximal inhibitions (IC50), respectively, of 1.2 nM and, minimally, 575.5 nM. The TTX-sensitive and-resistant Na+ currents were kinetically distinct; time-to-peak, τm, and τh for TTX-sensitive currents were shorter than for TTX-resistant currents. Steady-state voltage dependence of the two currents was indistinguishable. The presence of TTX-sensitive and-resistant Na+ currents, which are pharmacologically and kinetically distinct, led us to search for mRNAs known to be associated with TTX-resistant channels, in addition to the α subunit mRNAs, which have previously been shown to be expressed in these cells. Using RT-PCR and restriction enzyme mapping, we were unable to detect αSNS, but detected mRNA for rH1, which is known to encode a TTX-resistant channel, in B104 cells. B104 neuroblastoma cells thus express TTX-sensitive and -resistant Na+ currents. These appear to be encoded by neuronal-type and cardiac Na+ channel mRNAs including the RH1 transcript. This cell line may be useful for studies on the rH1 channel, which is known to be mutated in the long-QT syndrome.

1998 ◽  
Vol 79 (2) ◽  
pp. 648-658 ◽  
Author(s):  
Patrizia Tosetti ◽  
Vanni Taglietti ◽  
Mauro Toselli

Tosetti, Patrizia, Vanni Taglietti, and Mauro Toselli. Functional changes in potassium conductances of the human neuroblastoma cell line SH-SY5Y during in vitro differentiation. J. Neurophysiol. 79: 648–658, 1998. The electrophysiological properties of voltage-dependent outward currents were investigated under voltage-clamp conditions in the human neuroblastoma cell line SH-SY5Y before and after in vitro differentiation with retinoic acid, by using the whole cell variant of the patch-clamp technique. Voltage steps to depolarizing potentials from a holding level of −90 mV elicited, in both undifferentiated and differentiated cells, outward potassium currents that were blocked by tetraethylammonium, but were unaffected by 4-aminopyridine, cadmium, and by shifts of the holding potentials to −40 mV. These currents activated rapidly and inactivated slowly in a voltage-dependent manner. In undifferentiated cells the threshold for current activation was about −30 mV, with a steady-state half activation potential of 19.5 mV. Maximum conductance was 4.3 nS and mean conductance density was 0.34 mS/cm2. Steady-state half inactivation potential was −13.8 mV and ∼10% of the current was resistant to inactivation. Both activation and inactivation kinetics were voltage dependent. In differentiated cells the threshold for current activation was about −20 mV, with a half potential for steady-state activation of 37.0 mV. Maximum conductance was 15.2 nS and mean conductance density was 0.78 mS/cm2. Steady-state half inactivation potential was −9.7 mV and ∼37% of the current was resistant to inactivation. Both activation and inactivation kinetics were voltage dependent. This diversity in potassium channel properties observed between undifferentiated and differentiated cells was related to differences in cell excitability. Under current-clamp conditions, the action potential repolarization rate in differentiated cells was about threefold faster than that of the abortive action potentials elicitable in undifferentiated cells. Furthermore, during prolonged stimulation, trains of spikes could be generated in some differentiated cells but not in undifferentiated cells.


1976 ◽  
Vol 154 (1) ◽  
pp. 57-64 ◽  
Author(s):  
R A Mathews ◽  
T C Johnson ◽  
J E Hudson

A kinetic analysis of the appearance of 14C-labelled proteins in the surface membranes isolated from exponentially growing neuroblastoma cells (N2a) showed that the total membrane proteins reached a steady-state specific radioactivity in 18-20 h. However, examination of individual protein bands resolved by sodium dodecyl sulphate-urea-polyacrylamide-gel electrophoresis illustrated that differences in the kinetics of specific surface-membrane proteins could be detected. Although most of the protein bands reached a steady-state specific radioactivity at a time similar to that for total membrane proteins, at least two bands (mol. wt. 180000 and 130000) attained the steady-state within 8-10 h. It was shown by the use of dual-labelling techniques that these two protein bands turned over in the surface membranes of neuroblastoma N2a cells at least 180 and 150% faster than the total membrane protein. These two proteins were glycosylated and located on the outer surface of the cells, since they were labelled with radioactive carbohydrates and readily removed by treatment of the intact neuroblastoma cell with proteinases.


2011 ◽  
Vol 436 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Richard B. Parsons ◽  
Shylesh Aravindan ◽  
Anusha Kadampeswaran ◽  
Emily A. Evans ◽  
Kanwaljeet K. Sandhu ◽  
...  

NNMT (nicotinamide N-methyltransferase, E.C. 2.1.1.1) catalyses the N-methylation of nicotinamide to 1-methylnicotinamide. NNMT expression is significantly elevated in a number of cancers, and we have previously demonstrated that NNMT expression is significantly increased in the brains of patients who have died of Parkinson's disease. To investigate the cellular effects of NNMT overexpression, we overexpressed NNMT in the SH-SY5Y cell line, a tumour-derived human dopaminergic neuroblastoma cell line with no endogenous expression of NNMT. NNMT expression significantly decreased SH-SY5Y cell death, which correlated with increased intracellular ATP content, ATP/ADP ratio and Complex I activity, and a reduction in the degradation of the NDUFS3 [NADH dehydrogenase (ubiquinone) iron–sulfur protein 3] subunit of Complex I. These effects were replicated by incubation of SH-SY5Y cells with 1-methylnicotinamide, suggesting that 1-methylnicotinamide mediates the cellular effects of NNMT. Both NNMT expression and 1-methylnicotinamide protected SH-SY5Y cells from the toxicity of the Complex I inhibitors MPP+ (1-methyl-4-phenylpyridinium ion) and rotenone by reversing their effects upon ATP synthesis, the ATP/ADP ratio, Complex I activity and the NDUFS3 subunit. The results of the present study raise the possibility that the increase in NNMT expression that we observed in vivo may be a stress response of the cell to the underlying pathogenic process. Furthermore, the results of the present study also raise the possibility of using inhibitors of NNMT for the treatment of cancer.


1987 ◽  
Vol 248 (3) ◽  
pp. 691-696 ◽  
Author(s):  
W T Matten ◽  
P F Maness

A kinetic analysis of the tyrosine-specific protein kinase of pp60c-src from the C1300 mouse neuroblastoma cell line Neuro-2A and pp60c-src expressed in fibroblasts was carried out to determine the nature of the increased specific activity of the neuroblastoma enzyme. In immune-complex kinase assays with ATP-Mn2+ and the tyrosine-containing peptide angiotensin I as phosphoacceptor substrate, pp60c-src from the neuroblastoma cell line was characterized by a maximum velocity (Vmax.) that was 7-15-fold greater than the Vmax. of pp60c-src from fibroblasts. The neuroblastoma enzyme exhibited Km values for ATP (16 +/- 3 microM) and angiotensin I (6.8 +/- 2.6 mM) that were similar to Km values for ATP (25 +/- 3 microM) and angiotensin I (6.5 +/- 1.7 mM) of pp60c-src from fibroblasts. pp60v-src expressed in Rous-sarcoma-virus-transformed cells exhibited an ATP Km value (25 +/- 4 microM) and an angiotensin I Km value (6.6 +/- 0.5 mM) that approximated the values determined for pp60c-src in neuroblastoma cells and fibroblasts. These results indicate that the pp60c-src kinase from neuroblastoma cells has a higher turnover number than pp60c-src kinase from fibroblasts, and that the neural form of the enzyme would be expected to exhibit increased catalytic activity at the saturating concentrations of ATP that are found intracellularly.


1991 ◽  
Vol 19 (1) ◽  
pp. 39-40
Author(s):  
Dario Cova ◽  
Pietro Fumagalli ◽  
Angela Santagostino

The aim of our research was the in vitro evaluation of the neurotoxic effects of three EBDCs (Nabam, Zineb and Maneb) and ETU on SK-N-BE human neuroblastoma cells as a model for neurotoxicity in humans. The EC50 value was used as an index of the toxicities of these compounds. Since Zineb and Maneb contain zinc and manganese as cations, respectively, in order to determine the contributions of these metals, the EC50s of zinc chloride and manganese chloride were also evaluated. Nabam, Zineb and Maneb had EC50 values ranging from 1μM to 30μM; the EC50s of manganese and zinc in this human cell line were found to be of the same order of magnitude as those of the EBDC fungicides. These in vitro effects are discussed in relation to the possible use of neuronal cell lines for detecting the neurotoxicities of these compounds.


1984 ◽  
Vol 4 (11) ◽  
pp. 2370-2380 ◽  
Author(s):  
R W Michitsch ◽  
K T Montgomery ◽  
P W Melera

Screening of a partial cDNA library prepared from the human neuroblastoma cell line BE(2)-C with genomic DNA probes containing sequences representative of the amplified domain of that cell line allowed us to identify cloned transcripts from an active gene within the domain. The gene BE(2)-C-59 is amplified ca. 150-fold and encodes a 3.0- and a 1.5-kilobase RNA transcript, both of which are overproduced in BE(2)-C cells. A survey of a large variety of human tumor cell types indicated that this gene is amplified to varying degrees in all neuroblastoma cell lines and a retinoblastoma cell line that exhibit obvious cytological manifestations of DNA sequence amplification, i.e., homogeneously staining regions and double-minute chromosomes. The BE(2)-C-59 gene is not amplified, however, in other nonrelated tumor types, even those containing amplified DNA. Although the functional significance of this specific gene amplification in neuroblastoma cells remains unknown, an indication that it may relate to the malignant phenotype of these cells follows from the remainder of our data which show that the amplified BE(2)-C-59 gene shares partial homology with both the second and third exons, but not the first exon, of the human c-myc oncogene.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Christian Garcia ◽  
Jared Smith ◽  
Peter Malicky ◽  
Fletcher White

Background and Hypothesis: The pathogenesis of neuroblastoma remains elusive. In order to further understand the pathogenesis, it is necessary to identify molecular and cellular mechanisms of the cancer. One protein of interest is high-mobility group box 1 protein (HMGB1). HMGB1 has been implicated in cancer including tumor growth, invasion, angiogenesis, metastasis, relapse and therapeutic resistance. HMGB1 isoforms signals via different receptors including the chemokine receptor, CXCR4, receptor for advanced glycation end products (RAGE), and the prominent inflammation-associated receptor, toll-like receptor 4 (TLR4). To gain insight into the possible impact of HMGB1 on the SH-SY5Y neuroblastoma cell line, we determined the degree to which CXCR4, TLR4 and RAGE are present on SH-SY5Y cells. We hypothesize that the presence of these receptors in SH-SY5Y cells may mediate proliferation of neuroblastoma cells and other types of cancer. Experimental Design or Project Methods: The SH-SY5Y cell line (ATCC® CRL-2266™) was derived from a metastatic bone tumor in a 4 year old female. Cells were lysed in lysis buffer, electrophoresed on a 10% SDS-PAGE, and blotted onto PVDF membrane. After blocking, the membranes were incubated with primary antibodies against the receptor protein overnight at 4 °C, and then with HRP-conjugated secondary antibodies for 1h. Protein bands were visualized with a SuperSignal West Pico Chemiluminescent Substrate. Results: To be finalized Conclusion and Potential Impact: Investigating SH-SY5Y cell line for the presence of these inflammation-associated receptors could potentially serve as a model to better understand the role of these receptors in cancer research.


Author(s):  
Joanna Lazniewska ◽  
Katarzyna Milowska ◽  
Nadia Katir ◽  
Abdelkim Kadib ◽  
Maria Bryszewska ◽  
...  

AbstractDendrimers containing viologen (derivatives of 4,4′-bipyridyl) units in their structure have been demonstrated to exhibit antiviral activity against human immunodeficiency virus (HIV-1). It has also recently been revealed that novel dendrimers with both viologen units and phosphorus groups in their structure show different antimicrobial, cytotoxic and hemotoxic properties, and have the ability to influence the activity of cholinesterases and to inhibit α-synuclein fibrillation. Since the influence of viologen-phosphorus structures on basic cellular processes had not been investigated, we examined the impact of such macromolecules on the murine neuroblastoma cell line (N2a). We selected three water-soluble viologen-phosphorus (VPD) dendrimers, which differ in their core structure, number of viologen units and number and type of surface groups, and analyzed several aspects of the cellular response. These included cell viability, generation of reactive oxygen species (ROS), alterations in mitochondrial activity, morphological modifications, and the induction of apoptosis and necrosis. The MTT assay results suggest that all of the tested dendrimers are only slightly cytotoxic. Although some changes in ROS formation and mitochondrial function were detected, the three compounds did not induce apoptosis or necrosis. In light of these results, we can assume that the tested VPD are relatively safe for mouse neuroblastoma cells. Although more research on their safety is needed, VPD seem to be promising nanoparticles for further biomedical investigation.


2021 ◽  
Author(s):  
Hyun Sik Kim ◽  
Young Han Park ◽  
Mi Jung Kwon ◽  
Joon Ho Song ◽  
In Bok Chang

Abstract PurposeThe anti-tumor effect of the beta-adrenergic receptor antagonist propranolol in breast cancer is well known; however, its activity in glioblastoma is not well-evaluated. The Notch-Hes pathway is known to regulate cell differentiation, proliferation, and apoptosis. We investigated the effect of propranolol to human glioblastoma cell lines, and the role of Notch and Hes signaling in this process.MethodsWe performed immunohistochemical staining on 31 surgically resected primary human glioblastoma tissues. We also used glioblastoma cell lines of U87-MG, LN229, and neuroblastoma cell line of SH-SY5Y in this study. The effect of propranolol and isoproterenol on cell proliferation was evaluated using the MTT assay (absorbance 570nm). The impact of propranolol on gene expression (Notch and Hes) was evaluated using real-time (RT) PCR, whereas protein levels of Notch1 and Hes1 were measured using western blotting (WB), simultaneously. Small interfering RNA (siRNA) was used to suppress the Notch gene to investigate its role in the proliferation of glioblastoma.ResultsPropranolol and isoproterenol caused a dose-dependent decrease in cell proliferation (MTT assay). RT-PCR showed an increase in Notch1 and Hes1 expression by propranolol, whereas WB demonstrated increase in Notch1 protein, but a decrease in Hes1 by propranolol. The proliferation of U87-MG and LN229 was not significantly suppressed after transfection with Notch siRNA.ConclusionThese results demonstrated that propranolol suppressed the proliferation of glioblastoma cell lines and neuroblastoma cell line, and Hes1 was more closely involved than Notch1 was in glioblastoma proliferation.


1984 ◽  
Vol 4 (11) ◽  
pp. 2370-2380
Author(s):  
R W Michitsch ◽  
K T Montgomery ◽  
P W Melera

Screening of a partial cDNA library prepared from the human neuroblastoma cell line BE(2)-C with genomic DNA probes containing sequences representative of the amplified domain of that cell line allowed us to identify cloned transcripts from an active gene within the domain. The gene BE(2)-C-59 is amplified ca. 150-fold and encodes a 3.0- and a 1.5-kilobase RNA transcript, both of which are overproduced in BE(2)-C cells. A survey of a large variety of human tumor cell types indicated that this gene is amplified to varying degrees in all neuroblastoma cell lines and a retinoblastoma cell line that exhibit obvious cytological manifestations of DNA sequence amplification, i.e., homogeneously staining regions and double-minute chromosomes. The BE(2)-C-59 gene is not amplified, however, in other nonrelated tumor types, even those containing amplified DNA. Although the functional significance of this specific gene amplification in neuroblastoma cells remains unknown, an indication that it may relate to the malignant phenotype of these cells follows from the remainder of our data which show that the amplified BE(2)-C-59 gene shares partial homology with both the second and third exons, but not the first exon, of the human c-myc oncogene.


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