Murine Neuroblastoma Cells Research Articles

Triterpensaponins as a novel transfection enhancer

Recent studies have shown that triterpensaponins of Saponaria officinalis L. (Caryophyllaceae) and Gypsophila paniculata L. (Caryophyllaceae) are able to augment the effect of certain toxins such as ribosome inactivating proteins (RIPs) [1]. Due to their amphiphilic properties these saponins are able to interact with the endosome and lysosome membrane and thus enhance the release of the cargo into the cytosol [2]. In order to exploit this kind of interaction, in this study DNA containing nanoparticles were formulated and characterized to be applied together with saponins. Murine neuroblastoma cells were transfected with nanoplexes, containing mammalian plasmids with green fluorescing protein (GFP), Luciferase or the RIP Saporin of Saponaria officinalis L. A transfection with saponins showed a significant increase of transfection efficiency in terms of fluorescence, luminescence or viability compared to a transfection without saponin co-application. First in-vitro cell experiments showed a 6-fold increase of luciferase expression compared to nanoparticles alone. GFP-transfection even achieved a 33-fold increase of GFP-expression. With the co-application of saponins a transfection of 52% regarding all cells could be observed, while nanoparticles just showed an efficiency of 2%. Therefore triterpensaponins hold a great potential to improve the transfection efficiency and for being used as a valuable transfection booster in pharmaceutical therapies.

Simple oxygraphic analysis for the presence of adenylate kinase 1 and 2 in normal and tumor cells.

The adenylate kinase (AK) isoforms network plays an important role in the intracellular energy transfer processes, the maintenance of energy homeostasis, and it is a major player in AMP metabolic signaling circuits in some highly-differentiated cells. For this purpose, a rapid and sensitive method was developed that enables to estimate directly and semi-quantitatively the distribution between cytosolic AK1 and mitochondrial AK2 localized in the intermembrane space, both in isolated cells and tissue samples (biopsy material). Experiments were performed on isolated rat mitochondria or permeabilized material, including undifferentiated and differentiated neuroblastoma Neuro-2a cells, HL-1 cells, isolated rat heart cardiomyocytes as well as on human breast cancer postoperative samples. In these samples, the presence of AK1 and AK2 could be detected by high-resolution respirometry due to the functional coupling of these enzymes with ATP synthesis. By eliminating extra-mitochondrial ADP with an excess of pyruvate kinase and its substrate phosphoenolpyruvate, the coupling of the AK reaction with mitochondrial ATP synthesis could be quantified for total AK and mitochondrial AK2 as a specific AK index. In contrast to the creatine kinase pathway, the AK phosphotransfer pathway is up-regulated in murine neuroblastoma and HL-1 sarcoma cells and in these malignant cells expression of AK2 is higher than AK1. Differentiated Neuro-2a neuroblastoma cells exhibited considerably higher OXPHOS capacity than undifferentiated cells, and this was associated with a remarkable decrease in their AK activity. The respirometric method also revealed a considerable difference in mitochondrial affinity for AMP between non-transformed cells and tumor cells.

The impact of species and cell type on the nanosafety profile of iron oxide nanoparticles in neural cells.

BackgroundWhile nanotechnology is advancing rapidly, nanosafety tends to lag behind since general mechanistic insights into cell-nanoparticle (NP) interactions remain rare. To tackle this issue, standardization of nanosafety assessment is imperative. In this regard, we believe that the cell type selection should not be overlooked since the applicability of cell lines could be questioned given their altered phenotype. Hence, we evaluated the impact of the cell type on in vitro nanosafety evaluations in a human and murine neuroblastoma cell line, neural progenitor cell line and in neural stem cells. Acute toxicity was evaluated for gold, silver and iron oxide (IO)NPs, and the latter were additionally subjected to a multiparametric analysis to assess sublethal effects.ResultsThe stem cells and murine neuroblastoma cell line respectively showed most and least acute cytotoxicity. Using high content imaging, we observed cell type- and species-specific responses to the IONPs on the level of reactive oxygen species production, calcium homeostasis, mitochondrial integrity and cell morphology, indicating that cellular homeostasis is impaired in distinct ways.ConclusionsOur data reveal cell type-specific toxicity profiles and demonstrate that a single cell line or toxicity end point will not provide sufficient information on in vitro nanosafety. We propose to identify a set of standard cell lines for screening purposes and to select cell types for detailed nanosafety studies based on the intended application and/or expected exposure.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-016-0220-y) contains supplementary material, which is available to authorized users.

Effects of membrane properties on the binding activities of the HN and HC heavy-chain domains of botulinum neurotoxin A

Binding behaviors of the HN and the HC domains of BoNT/A were investigated individually to identify if there exist any differences in their interaction with the cell membrane. Recombinant fragments corresponding to both BoNT/A HN and HC regions were prepared (HN519–845 and HC967–1296) and their binding to synaptic proteins was verified. The binding behaviors of these heavy-chain domains were analyzed by treating the Neuro 2a, a murine neuroblastoma cell line, with compounds known to alter membrane properties. Cholesterol depletion and lipid raft inhibition increased the binding of HN519–845 to Neuro 2a cells without affecting HC967–1296-cell interaction. Sphingolipid depletion decreased the binding of cells to both HC967–1296 and HN519–845 whereas, loading exogenous GD1a, on to the Neuro 2a cells, increased the binding of both the peptides to cells. Microtubule disruption of the Neuro 2a cells by nocodazole decreased the binding of both HC967–1296 and HN519–845 to the treated cells. Inhibition of the clathrin-mediated endocytosis using dynasore, chlorpromazine or potassium (K+) depletion buffer lowered the binding of both HC967–1296 and HN519–845 to the cells, but seemed to exert a more pronounced effect on the binding of HC967–1296 than on the binding of HN519–845. Results indicate that while both the HN and HC domains are involved in the binding of the toxin to neuronal cells there are differences in their behavior which probably stem from their respective amino acid composition and structural location in the toxin three-dimensional structure along with their intended role in translocation and internalization into the cells.

Gene delivery efficiency and cytotoxicity of heterocyclic amine-modified PAMAM and PPI dendrimers

Poly-(amidoamine) (PAMAM) and poly-(propylenimine) (PPI) are the two most widely investigated dendrimers for drug and gene delivery. In order to enhance DNA transfection activity of these dendrimers, generation 3 and 4 PAMAM and generation 4 and 5 PPI were modified by partial substitution of surface primary amines with histidine, pyridine, and piperazine, which have buffering capacity properties. It was shown that higher dendrimer generations and higher grafting percentages (30% and 50% of primary amines) were associated with higher transfection activity. Pyridine was the most effective substituent for PPI, while piperazine-modified PAMAM dendrimers showed the best transfection efficiency among PAMAM-based vectors in murine neuroblastoma (Neuro-2a) cells. None of the modified carriers showed remarkable cytotoxicity in vitro. Pretreatment of cells with bafilomycin A indicated that endosomal buffering capacity is the main mechanism of endosomal escape. In conclusion, PAMAM and PPI may exhibit different gene delivery efficiency and cytotoxicity profiles with the same chemical modifications. These modified dendrimers could be considered as efficient and safe gene carriers in neuroblastoma cells in vitro.

Magnolol protects against trimethyltin-induced neuronal damage and glial activation in vitro and in vivo

Trimethyltin (TMT), an organotin with potent neurotoxic effects by selectively damaging to hippocampus, is used as a tool for creating an experimental model of neurodegeneration. In the present study, we investigated the protective effects of magnolol, a natural biphenolic compound, on TMT-induced neurodegeneration and glial activation in vitro and in vivo. In HT22 murine neuroblastoma cells, TMT induced necrotic/apoptotic cell death and oxidative stress, including intracellular reactive oxygen species (ROS), protein carbonylation, induction of heme oxygenase-1 (HO-1), and activation of all mitogen-activated protein kinases (MAPKs) family proteins. However, magnolol treatment significantly suppressed neuronal cell death by inhibiting TMT-mediated ROS generation and activation of JNK and p38 MAPKs. In BV-2 microglial cells, magnolol efficiently attenuated TMT-induced microglial activation via suppression of ROS generation and activation of JNK, p38 MAPKs, and nuclear factor-κB (NF-κB) signaling. In an in vivo mouse study, TMT induced massive neuronal damage and enhanced oxidative stress at day 2. We also observed a concomitant increase in glial cells and inducible nitric oxide synthase (iNOS) expression on the same day. These features of TMT toxicity were reversed by treatment of magnolol. We observed that p-JNK and p-p38 MAPK levels were increased in the mouse hippocampus at day 1 after TMT treatment and that magnolol blocked TMT-induced JNK and p38 MAPK activation. Magnolol administration prevented TMT-induced hippocampal neurodegeneration and glial activation, possibly through the regulation of TMT-mediated ROS generation and MAPK activation.

Safety and immunogenicity of recombinant rabies virus (ERAGS) in mice and raccoon dogs.

PurposeThe development of a genetically modified live rabies vaccine applicable to wild raccoon dogs is necessary for the eradication of rabies in Korea. Thus, we constructed a recombinant rabies virus (RABV) called the ERAGS strain, using a reverse genetic system and evaluated its safety and efficacy in mice and its safety and immunogenicity in raccoon dogs.Materials and MethodsERAGS, which has Asn194Ser and Arg333Glu substitutions in the glycoprotein, was constructed using site-directed mutagenesis. Mice were inoculated with the ERAGS strain (either 105.0 or 107.0 FAID50/mL) via intramuscular (IM) or intracranial injections and then challenged with a virulent RABV. Raccoon dogs were administered the ERAGS strain (108.0 FAID50/mL) either orally or via the IM route and the immunogenicity of the strain was evaluated using fluorescent antibody virus neutralization tests.ResultsThe ERAGS strain inoculated into murine neuroblastoma cells reached 107.8 FAID50/mL at 96-hour post-inoculation. The virus was not pathogenic and induced complete protection from virulent RABV in immunized 4- and 6-week-old mice. Korean raccoon dogs immunized with the ERAGS strain via IM or oral route were also safe from the virus and developed high titer levels (26.4-32.8 IU/mL) of virus-neutralizing antibody (VNA) at 4 weeks post-inoculation.ConclusionThe ERAGS RABV strain was effectively protective against rabies in mice and produced a high VNA titer in raccoon dogs.

Ex vivo induction of antitumor DEC-205+ CD11c+ cells in a murine neuroblastoma model by co-stimulation with doxorubicin, lipopolysaccharide and interleukin-4.

The antigen-presenting capacity of specific cells and tumor immunogenicity involved in innate cellular immunity are important for initiating an antitumor response to advanced neuroblastoma. The present study was performed to establish a method of producing antigen-presenting cells that induced an immune response to murine neuroblastoma cells through culture with neuroblastoma cells that had undergone immunogenic cell death. Immunogenic death of neuro-2a murine neuroblastoma cells was induced by exposure to doxorubicin. Mouse bone marrow cells were cultured in medium containing granulocyte-macrophage colony-stimulating factor, followed by the addition of doxorubicin-treated neuro-2a cells to the culture with or without lipopolysaccharide (LPS) and/or interleukin-4. Subsequently, cluster of differentiation (CD) 8α+ lymphocytes were co-cultured with neuro-2a cells and the adherent bone marrow cells obtained by the above procedure to evaluate CD8α+ lymphocyte proliferation and interferon-γ production. Furthermore, the surface antigen profile of adherent bone marrow cells was analyzed by flow cytometry. When adherent bone marrow cells were treated with LPS and/or interleukin-4, followed by co-culture with CD8α+ lymphocytes and neuro-2a cells, interferon-γ production by the CD8α+ cells increased in response to anti-CD3/CD28 antibody stimulation. CD11c major histocompatibility complex II (MHC II) double-positive cells were increased among adherent cells derived from cultured bone marrow cells. These cells were positive for DEC-205, but not CD8α. These findings suggest that co-culture of bone marrow-derived cells with tumor cells (that have undergone immunogenic death by exposure to doxorubicin) plus stimulation by LPS and interleukin-4 induces antigen-presenting cells that can evoke an immune response to neuroblastoma. Bone marrow-derived DEC-205+ CD11c+ MHC II+ dendritic cells are key antigen-presenting cells in the induction of an immune response following phagocytosis of doxorubicin-treated neuroblastoma cells.

Ability of Indian street rabies virus isolates to induce apoptosis by in-vitro

An attempt had been made in this study to know the ability of Indian street rabies virus isolates to induce apoptosis in murine neuroblastoma cells. Thirty Indian street virus isolates were tested by fluorescent antibody technique (FAT) among which 20 samples was positive. These positive samples were used to infect murine neuroblastoma (MNA) cells. Four street rabies virus isolates and challenge virus strain (CVS) were used in this study to show their ability to induce apoptosis. Total RNA was isolated and cDNA was synthesized by using gene specific primers pertaining to Caspase-1, BAD (Proapoptotic gene) and Glycoprotein gene of rabies virus. Challenge Virus Standard has been used as control in the amplification as well as in the demonstration of apoptosis. The expression of Caspase-1, BAD and glycoprotein genes in the murine neuroblastoma cells in comparision with CVS was measured by using densitometer. Street virus isolates expressed higher levels of Caspase-1 and BAD in comparison with CVS. Further TUNEL staining method showed higher apoptotic index when compared to CVS. This study is an initial attempt to exhibit the ability of Indian rabies street virus isolates to induce apoptosis in murine neuroblastoma cells (in vitro).

Synthesis of efficient gene delivery systems by grafting pegylated alkylcarboxylate chains to PAMAM dendrimers: Evaluation of transfection efficiency and cytotoxicity in cancerous and mesenchymal stem cells.

The applications of polyamidoamine (PAMAM) dendrimers have attracted much attention in biomedicine specially non-viral gene delivery because of thier unique characteristics including hyperbranching, multivalency, and well-defined uniform globular three-dimensional structures. In the current study, in order to enhance the transfection efficiency and reduce the cytotoxicity of PAMAMs, bromoalkylcarboxylates with different chain length (2-bromoacetic, 6-bromohexanoic, 10-bromodecanoic and 16-bromohexadecanoic acids) were covalently conjugated with 10% and 30% of primary amines of generation 4 and 5 (G4 and G5) of PAMAM dendrimers to increase the hydrophobicity of the carrier. At the next stage, the alkylcarboxylate-PAMAMs were pegylaed to further modify the PAMAM structures for biological applications. Obtained results demonstrated that the prepared PAMAM derivatives had particle size around 140 nm with net-positive surface charge. None of the prepared PAMAM-based non-viral vactors exhibited significant hemolytic activity and also cytotoxicity. Meanwhile decahexanoate-PAMAM G4 [G4(16C-10%)] and decanoate-PAMAM G4 conjugated to polyethylene glycol (PEG) (G4[(10C-30%)(10C-PEG)]) showed highest transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, interestingly only the latter had improved transfection efficiency in mesenchymal stem cells (MSCs). This study proved the potential utility of alkylcarboxylate-grafted PAMAM dendrimers (G4 and G5) with or without PEG modification for efficient gene transfer into cancerous cells as well as MSCs.

Heterocyclic amine-modified polyethylenimine as gene carriers for transfection of mammalian cells

Branched polyethylenimine (PEI) is extensively used as a polycationic non-viral vector for gene delivery. Polyplexes formed with PEI are believed to be released from endocytotic vesicles by the osmotic burst mechanism in the rate-limiting step in transfection. Increasing the buffering capacity of PEI derivatives in the endosomal pH range of 4.5–7.5 should enhance transfection efficiency. In this study, PEI was derivatized by covalently attaching heterocyclic amine moieties (piperazine, pyridine and imidazole rings with pKa values from 5.23 to 6.04) through amide bonds. PEI derivatives with 50% of the primary amines on PEI exhibited increased buffering capacity, increased transfection activity and decreased cytotoxicity in murine neuroblastoma (Neuro-2a) cells. The relative effectiveness in enhancing transfection efficiency was piperazine>pyridine>histidine, but each type of amine was the most effective under a particular set of conditions. Modified vectors could significantly improve transfection efficiency in murine mesenchymal stem cells. PEI25 derivatized at 50% with histidine administered as polyplexes in the tail veins of mice resulted in remarkably enhanced luciferase gene expression in the expected organ distribution and much lower toxicity than underivatized PEI25.

Integrin α4 Enhances Metastasis and May Be Associated with Poor Prognosis in MYCN-low Neuroblastoma.

High-risk neuroblastoma is associated with an overall survival rate of 30–50%. Neuroblastoma-expressed cell adhesion receptors of the integrin family impact cell adhesion, migration, proliferation and survival. Integrin α4 is essential for neural crest cell motility during development, is highly expressed on leukocytes, and is critical for transendothelial migration. Thus, cancer cells that express this receptor may exhibit increased metastatic potential. We show that α4 expression in human and murine neuroblastoma cell lines selectively enhances in vitro interaction with the alternatively spliced connecting segment 1 of fibronectin, as well as vascular cell adhesion molecule-1 and increases migration. Integrin α4 expression enhanced experimental metastasis in a syngeneic tumor model, reconstituting a pattern of organ involvement similar to that seen in patients. Accordingly, antagonism of integrin α4 blocked metastasis, suggesting adhesive function of the integrin is required. However, adhesive function was not sufficient, as mutants of integrin α4 that conserved the matrix-adhesive and promigratory function in vitro were compromised in their metastatic capacity in vivo. Clinically, integrin α4 is more frequently expressed in non-MYNC amplified tumors, and is selectively associated with poor prognosis in this subset of disease. These results reveal an unexpected role for integrin α4 in neuroblastoma dissemination and identify α4 as a potential prognostic indicator and therapeutic target.

Co-culture: A quick approach for isolation of street rabies virus in murine neuroblastoma cells.

Background:Laboratory detection of rabies in most cases is based on detection of the antigen by fluorescent antibody test, however, in weak positive cases confirmative laboratory diagnosis depends on widely accepted mouse inoculation test. Cell lines like neuroblastoma have been used to isolate the virus with greater success not only to target for diagnosis, but also for molecular studies that determine the epidemiology of the circulating street rabies strains and in studies that look at the efficiency of the developed monoclonal antibodies to neutralize the different rabies strains. Due to the recent issues in obtaining ethical permission for mouse experimentation, and also the passages required in the cell lines to isolate the virus, we report herewith a co-culture protocol using the murine neuroblastoma (MNA) cells, which enable quicker isolation of street rabies virus with minimum passages.Objective:This study is not to have an alternative diagnostic assay, but an approach to produce sufficient amount of rabies virus in minimum passages by a co-culture approach in MNA cells.Materials and Methods:The MNA cells are co-cultured by topping the normal cells with infected cells every 48 h and the infectivity was followed up by performing direct fluorescent-antibody test.Results:The co-culture approach results in 100% infectivity and hence the use of live mouse for experimentation could be avoided.Conclusion:Co-culture method provides an alternative for the situations with limited sample volume and for the quicker isolation of virus which warrants the wild type strains without much modification.

Acyl-coenzyme A:cholesterol acyltransferase 1 blockage enhances autophagy in the neurons of triple transgenic Alzheimer's disease mouse and reduces human P301L-tau content at the presymptomatic stage

Patients with Alzheimer's disease (AD) display amyloidopathy and tauopathy. In mouse models of AD, pharmacological inhibition using small molecule enzyme inhibitors or genetic inactivation of acyl-coenzyme A (Acyl-CoA):cholesterol acyltransferase 1 (ACAT1) diminished amyloidopathy and restored cognitive deficits. In microglia, ACAT1 blockage increases autophagosome formation and stimulates amyloid β peptide1-42 degradation. Here, we hypothesize that in neurons ACAT1 blockage augments autophagy and increases autophagy-mediated degradation of P301L-tau protein. We tested this possibility in murine neuroblastoma cells ectopically expressing human tau and in primary neurons isolated from triple transgenic AD mice that express mutant forms of amyloid precursor protein, presenilin-1, and human tau. The results show that ACAT1 blockage increases autophagosome formation and decreases P301L-tau protein content without affecting endogenous mouse tau protein content. In vivo, lacking Acat1 decreases P301L-tau protein content in the brains of young triple transgenic AD mice but not in those of old mice, where extensive hyperphosphorylations and aggregation of P301L-tau take place. These results suggest that, in addition to ameliorating amyloidopathy in both young and old AD mice, ACAT1 blockage may benefit AD by reducing tauopathy at early stage.

Mitochondrial toxicity of triclosan on mammalian cells

Effects of triclosan (5-chloro-2′-(2,4-dichlorophenoxy)phenol) on mammalian cells were investigated using human peripheral blood mono nuclear cells (PBMC), keratinocytes (HaCaT), porcine spermatozoa and kidney tubular epithelial cells (PK-15), murine pancreatic islets (MIN-6) and neuroblastoma cells (MNA) as targets. We show that triclosan (1–10μgml−1) depolarised the mitochondria, upshifted the rate of glucose consumption in PMBC, HaCaT, PK-15 and MNA, and subsequently induced metabolic acidosis. Triclosan induced a regression of insulin producing pancreatic islets into tiny pycnotic cells and necrotic death. Short exposure to low concentrations of triclosan (30min, ≤1μg/ml) paralyzed the high amplitude tail beating and progressive motility of spermatozoa, within 30min exposure, depolarized the spermatozoan mitochondria and hyperpolarised the acrosome region of the sperm head and the flagellar fibrous sheath (distal part of the flagellum). Experiments with isolated rat liver mitochondria showed that triclosan impaired oxidative phosphorylation, downshifted ATP synthesis, uncoupled respiration and provoked excessive oxygen uptake. These exposure concentrations are 100–1000 fold lower that those permitted in consumer goods. The mitochondriotoxic mechanism of triclosan differs from that of valinomycin, cereulide and the enniatins by not involving potassium ionophoric activity.

TM-06 * MYC AND MYCN DISRUPTION OF THE MOLECULAR CLOCK IN CANCER CELLS

Cancer cells are known to have a metabolic advantage, but it is not known whether the circadian clock, which couples metabolic and cell cycles, restrains cancer cell metabolism and growth. We report that the deregulated expression of the MYC or MYCN oncogene disrupts the molecular clock by inducing NR1D1 (Rev-erbα) to diminish expression and dampen oscillation of ARNTL (Bmal1) that could be rescued by knockdown of Rev-erb. The expression of Rev-erbα is highly correlated with MYC expression in human B cell lymphoma, human T-cell acute lymphoblastic leukemia, murine hepatocellular carcinoma cells and human neuroblastoma cells. MYC or MYCN directly upregulates Rev-erbα expression by binding to its promoter. Suppression of Rev-erbα diminished hepatocellular cancer cell growth, illustrating Rev-erbα's role in MYC-induced tumorigenesis. Furthermore, Rev-erbα expression is a predictor of poor clinical outcome for human neuroblastoma and correlates with MYCN expression. Our results demonstrate an unsuspected link between oncogenic transformation and circadian arrhythmia, which may be metabolically advantageous for cancer cells. Having observed that Myc and N-Myc disrupt circadian rhythm in tumor cells, suggesting a therapeutic opportunity could exist in the window between circadian regulation of the ebb-and-flow of normal cell metabolism and the sustained, not oscillate non-circadian cancer metabolism. The understanding of these basic mechanisms from our work should lead to better cancer treatment strategies that reduce side effects and increase effectiveness.

Centrosome-declustering drugs mediate a two-pronged attack on interphase and mitosis in supercentrosomal cancer cells.

Classical anti-mitotic drugs have failed to translate their preclinical efficacy into clinical response in human trials. Their clinical failure has challenged the notion that tumor cells divide frequently at rates comparable to those of cancer cells in vitro and in xenograft models. Given the preponderance of interphase cells in clinical tumors, we asked whether targeting amplified centrosomes, which cancer cells carefully preserve in a tightly clustered conformation throughout interphase, presents a superior chemotherapeutic strategy that sabotages interphase-specific cellular activities, such as migration. Herein we have utilized supercentrosomal N1E-115 murine neuroblastoma cells as a test-bed to study interphase centrosome declustering induced by putative declustering agents, such as Reduced-9-bromonoscapine (RedBr-Nos), Griseofulvin and PJ-34. We found tight ‘supercentrosomal' clusters in the interphase and mitosis of ~80% of patients' tumor cells with excess centrosomes. RedBr-Nos was the strongest declustering agent with a declustering index of 0.36 and completely dispersed interphase centrosome clusters in N1E-115 cells. Interphase centrosome declustering caused inhibition of neurite formation, impairment of cell polarization and Golgi organization, disrupted cellular protrusions and focal adhesion contacts—factors that are crucial prerequisites for directional migration. Thus our data illustrate an interphase-specific potential anti-migratory role of centrosome-declustering agents in addition to their previously acknowledged ability to induce spindle multipolarity and mitotic catastrophe. Centrosome-declustering agents counter centrosome clustering to inhibit directional cell migration in interphase cells and set up multipolar mitotic catastrophe, suggesting that disbanding the nuclear–centrosome–Golgi axis is a potential anti-metastasis strategy.

Differences in receptor binding affinity of several phytocannabinoids do not explain their effects on neural cell cultures

Phytocannabinoids are potential candidates for neurodegenerative disease treatment. Nonetheless, the exact mode of action of major phytocannabinoids has to be elucidated, but both, receptor and non-receptor mediated effects are discussed. Focusing on the often presumed structure–affinity-relationship, Ki values of phytocannabinoids cannabidiol (CBD), cannabidivarin (CBDV), cannabichromene (CBC), cannabigerol (CBG), cannabinol (CBN), THC acid (THCA) and THC to human CB1 and CB2 receptors were detected by using competitive inhibition between radioligand [3H]CP-55,940 and the phytocannabinoids. The resulting Ki values to CB1 range from 23.5μM (THCA) to 14,711μM (CBDV), whereas Ki values to CB2 range from 8.5μM (THCA) to 574.2μM (CBDV). To study the relationship between binding affinity and effects on neurons, we investigated possible CB1 related cytotoxic properties in murine mesencephalic primary cell cultures and N18TG2 neuroblastoma cell line. Most of the phytocannabinoids did not affect the number of dopaminergic neurons in primary cultures, whereas propidium iodide and resazurin formation assays revealed cytotoxic properties of CBN, CBDV and CBG. However, THC showed positive effects on N18TG2 cell viability at a concentration of 10μM, whereas CBC and THCA also displayed slightly positive activities. These findings are neither linked to structural characteristics nor to the receptor binding affinity therewith pointing to another mechanism than a receptor mediated one.

A gammaherpesvirus establishes persistent infection in neuroblastoma cells.

Gammaherpesvirus (γHV) infection of the central nervous system (CNS) has been implicated in diverse neurological diseases, and murine γHV-68 (MHV-68) is known to persist in the brain after cerebral infection. The underlying molecular mechanisms of persistency of virus in the brain are poorly understood. Here, we characterized a unique pattern of MHV-68 persistent infection in neuroblastoma cells. On infection with MHV-68, both murine and human neuroblastoma cells expressed viral lytic proteins and produced virions. However, the infected cells survived productive infection and could be cultured for multiple passages without affecting their cellular growth. Latent infection as well as productive replication was established in these prolonged cultures, and lytic replication was further increased by treatment with lytic inducers. Our results provide a novel system to study persistent infection of γHVs in vitro following de novo infection and suggest application of MHV-68 as a potential gene transfer vector to the brain.

The herbal compound geniposide rescues formaldehyde-induced apoptosis in N2a neuroblastoma cells

The herbal medicine Tong Luo Jiu Nao (TLJN) contains geniposide (GP) and ginsenoside Rg1 at a molar ratio of 10:1. Rg1 is the major component of another herbal medicine, panax notoginseng saponin (PNS). TLJN has been shown to strengthen brain function in humans, and in animals it improves learning and memory. We have previously shown that TLJN reduces amyloidogenic processing in Alzheimer's disease (AD) mouse models. Together this suggests TLJN may be a potential treatment for patients with dementia. Because chronic damage of the central nervous system by formaldehyde (FA) has been presented as a risk factor for age-associated cognitive dysfunction, in the present study we investigated the protective effect of both TLJN and GP in neuron-like cells exposed to FA. FA-exposed murine N2a neuroblastoma cells were incubated with TLJN, its main ingredient GP, as well as PNS, to measure cell viability and morphology, the rate of apoptosis and expression of genes encoding Akt, FOXO3, Bcl2 and p53. The CCK-8 assay, cytoskeletal staining and flow cytometry were used to test cell viability, morphology and apoptosis, respectively. Fluorescent quantitative real-time PCR (qRT-PCR) was used to monitor changes in gene expression, and HPLC to determine the rate of FA clearance. Treatment of N2a cells with 0.09 mmol L(-1) FA for 24 h significantly reduced cell viability, changed cell morphology and promoted apoptosis. Both TLJN and GP conferred neuroprotection to FA-treated N2a cells, whereas PNS, which had to be used at lower concentrations because of its toxicity, did not. Our data demonstrate that TLJN can rescue neuronal damage caused by FA and that its main ingredient, GP, has a major role in this efficacy. This presents purified GP as a drug or lead compound for the treatment of AD.