Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1-Phenyl-2-decanolyamino-3-morpholino-1-propanol (PDMP), an effective inhibitor of UDP-glucose:ceramide glucosyltransferase, caused inhibition of cell growth in murine neuroblastoma cell lines. Metabolic labeling of glycosphingolipids with [14C]galactose in NS-20Y, Neuro2a, and N1E-115 cells showed reduced incorporation of radioactivity into gangliosides and neutral glycosphingolipids when threo-PDMP was present in the medium. Treatment of NS-20Y cells with threo-PDMP resulted in a time-dependent decrease in mass levels of gangliosides and neutral glycosphingolipids. After 24 h in the presence of 50 microM threo-PDMP, neutral glycosphingolipid mass was reduced to 32%, where glucosylceramide was the most affected (90% decrease). The ganglioside mass was reduced to 57% of the original content. Neurite outgrowth from neuroblastoma cells in serum-free medium was significantly inhibited by threo-PDMP in a dose-dependent manner. Threo-PDMP also caused retraction of neurites which had been induced to extend in serum-free medium. Pretreatment of cells with GM1 partially restored the ability of NS-20Y cells for neurite outgrowth in the medium containing threo-PDMP. These results suggest a possible role for glycosphingolipids in neurite outgrowth of murine neuroblastoma cells.
 ...
PMID:Effects of an inhibitor of glucosylceramide synthase on glycosphingolipid synthesis and neurite outgrowth in murine neuroblastoma cell lines. 183 39

Shedding of tumor cell gangliosides may contribute to tumor cell escape from host immune destruction. Thus, it would be of interest to block the shedding of these immunosuppressive molecules. To this end, we studied a ceramide analogue, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP). D-PDMP is a potent inhibitor of glucosylceramide synthase and thereby the synthesis of cellular glycosphingolipids. Exposure of LAN-5 human neuroblastoma cells to 10 microM D-PDMP for 5 days almost completely abolished the shedding of gangliosides (from 240 to 8 pmol/10(8) cells/h), whereas cellular ganglioside synthesis was reduced by 90%. A shorter (3-day) treatment of LAN-5 cells with 10 microM D-PDMP was already effective in inhibiting shedding (by 86%) even while the cellular ganglioside content was still high. Specificity was evidenced by the only minimal effect of D-PDMP on the synthesis of sphingomyelin and phosphatidylcholine. Therefore, certain pharmacological agents, such as D-PDMP, may be useful in abrogating tumor ganglioside shedding and its consequent biological effects in vivo.
 ...
PMID:Abrogation of shedding of immunosuppressive neuroblastoma gangliosides. 884 Sep 70

Gangliosides are believed to play a critical role in cellular differentiation. To test this concept, we determined the effect of inhibition of endogenous ganglioside synthesis upon neurite formation induced by retinoic acid in LAN-5 human neuroblastoma cells. Ganglioside synthesis and content of LAN-5 cells exposed for 6 days to 10 microM D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) (an inhibitor of glucosylceramide synthase) were reduced by >90%. However, these ganglioside-depleted cells were not blocked from forming neurites when exposed to 10 microM retinoic acid. Even more extensive treatment of LAN-5 cells with 20 microM D-PDMP (6 day pretreatment followed by 6 days together with 10 microM retinoic acid) still did not block the retinoic acid-induced neurite formation. An element of neuroblastoma tumor cell differentiation, neurite formation, is therefore dependent neither on an intact cellular ganglioside complement nor on new ganglioside synthesis.
 ...
PMID:Inhibition of endogenous ganglioside synthesis does not block neurite formation by retinoic acid-treated neuroblastoma cells. 899 43

Hemopoiesis is disturbed in bone marrow-involving cancers like leukemia and neuroblastoma. Shedding of gangliosides by tumor cells may contribute to this tumor-induced bone marrow suppression. We studied in vitro the inhibitory effects of murine neuroblastoma cells (Neuro-2a and C1300) and their gangliosides on hemopoiesis using normal murine hemopoietic progenitor colony-forming assays. Transwell cultured neuroblastoma cells showed a dose-dependent inhibition on hemopoiesis, indicating that a soluble factor was responsible for this effect. Furthermore, the supernatant of Neuro-2a cultured cells inhibited hemopoietic proliferation and differentiation. To determine whether the inhibitory effect was indeed due to shed gangliosides and not, for instance, caused by cytokines, the effect of DL-threo-1 -phenyl-2-decanoylamino-3-morpholino-1-propanol (DL-PDMP) on Neuro-2a cells was studied. DL-PDMP is a potent inhibitor of glucosylceramide synthase, resulting in inhibition of the synthesis and shedding of gangliosides. The initially observed inhibitory effect of supernatant of Neuro-2a cells was abrogated by culturing these cells for 3 days in the presence of 10 microM DL-PDMP. Moreover, gangliosides isolated from Neuro-2a cell membranes inhibited hemopoietic growth. To determine whether the described phenomena in vitro are a reflection of bone marrow suppression occurring in vivo, gangliosides isolated from plasma of neuroblastoma patients were tested for their effects on human hemopoietic progenitor colony-forming assays. These human neuroblastoma-derived gangliosides inhibited normal erythropoiesis (colony-forming unit-erythroid/burst-forming unit-erythroid) and myelopoiesis (colony-forming unit-granulocyte/macrophage) to a higher extent compared with gangliosides isolated from control plasma. Altogether these results suggest that gangliosides shed by neuroblastoma cells inhibit hemopoiesis and may contribute to the observed bone marrow depression in neuroblastoma patients.
 ...
PMID:Inhibition of hemopoiesis in vitro by neuroblastoma-derived gangliosides. 980 88

An in vitro model of Gaucher's disease in murine neuroblastoma x rat glioma NG108-15 cells was used to investigate the physiological effects of two specific inhibitors of glucosylceramide synthase, d,l-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (d,l-PDMP) and N-butyldeoxynojirimycin (NB-DNJ), which have been suggested as agents for treatment of glycolipid storage disorders. Incubation of NG108-15 cells with conduritol-B-epoxide, a covalent inhibitor of glucosylceramidase, raised the intracellular concentration of glucosylceramide (GC) by more than fourfold, indicating a glycolipid composition equivalent to that of Gaucher's cells. The level of GC was decreased, and the cells were depleted of gangliosides by postincubation with d,l-PDMP or NB-DNJ. Treatment with d,l-PDMP, but not with NB-DNJ, resulted in a dose-dependent reduction of the growth rate and eventually caused cell death in NG108-15 cells on reaching confluency. An in situ detection assay using terminal nucleotidyltransferase indicated that cell degeneration was accompanied by apoptosis. Lipid analysis by high-performance TLC revealed that on incubation with d,l-PDMP, but not with NB-DNJ, the concentration of endogenous ceramide was elevated by threefold. Ceramide elevation and apoptosis were also observed when NG108-15 cells were incubated with daunorubicin, which was previously reported to induce programmed cell death by stimulation of ceramide synthesis. Structural characterization by HPLC and subsequent laser desorption mass spectrometry revealed that the endogenous ceramide contained fatty acids with chain lengths ranging from C14:0 to C24:0. The results indicate that elevation of levels of these ceramide species by incubation with d,l-PDMP or daunorubicin induces programmed cell death in NG108-15 cells. Because ceramide accumulation and cell death were not observed on incubation with NB-DNJ, its use is suggested to be less toxic than that of d,l-PDMP for treatment of Gaucher's disease and other sphingolipid storage disorders.
 ...
PMID:Differential effects of glycolipid biosynthesis inhibitors on ceramide-induced cell death in neuroblastoma cells. 1003 75

Neuroblastoma (NB), a tumor of the sympathetic nervous system, is the most common extracranial solid tumor in children. NB-derived gangliosides inhibit the functional activity of T and natural killer cells, contribute to tumor-induced bone marrow suppression, and cause multiple alterations of hematopoiesis, resulting in pancytopenia. However, the role of gangliosides in the regulation of dendritic cell (DC) generation (dendropoiesis) has not been studied. Using murine and human NB cell lines, we demonstrated that coincubation of murine bone marrow progenitors or human CD34+ progenitor cells with NB cells resulted in a significant inhibition of dendropoiesis in vitro up to 90%. The number of DCs was assessed by FACScan determination of CD83+ or CD11c+ cells coexpressing MHC class II and CD86 molecules. In addition, inhibition of antigen-presenting properties of DCs cultured in the presence of NB cells was observed in allogeneic mixed leukocyte reaction (33,508 +/- 1,613 cpm for control DCs versus 17,428 +/- 152 cpm for NB-treated DCs; P < 0.05). Treatment of NB cells with 10 microM DL-threo-1-phenyl-2-decanolylamine-3-morpholino-1-propanol HCl, an inhibitor of glucosylceramide synthase, markedly abrogated ganglioside synthesis and was accompanied by blockade of NB ability to inhibit dendropoiesis. Furthermore, purified gangliosides added to DC cultures significantly inhibited DC generation. The percentage of CD83+ cells decreased from 51.8 +/- 6.1% in the control group to 12.9 +/- 2.7% in cultures treated with GD2 (P < 0.05). Thus, our results demonstrate that NB-derived gangliosides inhibit the generation of functionally active DCs and may play a role in tumor-induced immunosuppression and subsequent tumor escape from immune recognition and elimination.
 ...
PMID:Neuroblastoma-derived gangliosides inhibit dendritic cell generation and function. 1119 88

Synthetic retinoids such as fenretinide [N-(4-hydroxyphenyl)retinamide] induce apoptosis of neuroblastoma cells, act synergistically with chemotherapeutic drugs, and may provide opportunities for novel approaches to neuroblastoma therapy. Fenretinide-induced cell death of neuroblastoma cells is caspase dependent and results in the release of cytochrome c from mitochondria independently of changes in permeability transition. This is mediated by a signaling pathway characterized by the generation of reactive oxygen species (ROS) via 12-lipoxygenase (12-LOX), and an oxidative-stress-dependent induction of the transcription factor, GADD153 and the BCL2-related protein BAK. Upstream events of fenretinide-induced signaling involve increased levels of ceramide as a result of increased sphingomyelinase activity, and the subsequent metabolism of ceramide to gangliosides via glucosylceramide synthase and GD3 synthase. These gangliosides may be involved in the regulation of 12-LOX leading to oxidative stress and apoptosis via the induction of GADD153 and BAK. The targeting of sphingomyelinases or downstream effectors such as 12-LOX or GADD153 may present novel approaches for the development of more effective and selective drugs for neuroblastoma therapy.
 ...
PMID:Molecular mechanisms of fenretinide-induced apoptosis of neuroblastoma cells. 1565 Feb 34

Fenretinide is thought to induce apoptosis via increases in ceramide levels but the mechanisms of ceramide generation and the link between ceramide and subsequent apoptosis in neuroblastoma cells is unclear. In SH-SY5Y neuroblastoma cells, evidence suggests that acid sphingomyelinase activity is essential for the induction of ceramide and apoptosis in response to fenretinide. Downstream of ceramide, apoptosis in response to fenretinide is mediated by increased glucosylceramide synthase activity resulting in increased levels of gangliosides GD3 and GD2 via GD3 synthase. GD3 is a key signalling intermediate leading to apoptosis via the activation of 12-Lipoxygenase, and the parallel induction of GD2 suggests that fenretinide might enhance the response of neuroblastoma to therapy with anti-GD2 antibodies.
 ...
PMID:The role of gangliosides in fenretinide-induced apoptosis of neuroblastoma. 1590 65

The sphingolipid ceramide has been recognized as an important mediator in the apoptotic machinery, and its efficient conversion to glucosylceramide has been associated with multidrug resistance. Therefore, inhibitors of glucosylceramide synthase are explored as tools for treatment of cancer. In this study, we used D,L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol to sensitize Neuro-2a murine neuroblastoma cells to the microtubule-stabilizing agent paclitaxel. This treatment resulted in a synergistic inhibition of viable cell number increase, which was based on a novel mechanism: (a) After a transient mitotic arrest, cells proceeded through an aberrant cell cycle resulting in hyperploidy. Apoptosis also occurred but to a very limited extent. (b) Hyperploidy was not abrogated by blocking de novo sphingolipid biosynthesis using ISP-1, ruling out involvement of ceramide as a mediator. (c) Cyclin-dependent kinase 1 and 2 activities were synergistically decreased on treatment. In conclusion, instead of inducing apoptosis through ceramide accumulation, D,L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol by itself affects cell cycle-related proteins in paclitaxel-arrested Neuro-2a cells resulting in aberrant cell cycle progression leading to hyperploidy.
 ...
PMID:PDMP sensitizes neuroblastoma to paclitaxel by inducing aberrant cell cycle progression leading to hyperploidy. 1654 73

Previous studies have indicated a role for glucosylceramide synthase (GCS) in multidrug resistance (MDR), either related to turnover of ceramide (Cer) or generation of gangliosides, which modulate apoptosis and/or the activity of ABC transporters. This study challenges the hypothesis that gangliosides modulate the activity of ABC transporters and was performed in two human neuroblastoma cell lines, expressing either functional P-glycoprotein (Pgp) or multidrug resistance-related protein 1 (MRP1). Two inhibitors of GCS, D,L-threo-1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol (t-PPPP) and N-butyldeoxynojirimycin (NB-dNJ), very efficiently depleted ganglioside content in two human neuroblastoma cell lines. This was established by three different assays: equilibrium radiolabeling, cholera toxin binding, and mass analysis. Fluorescence-activated cell sorting (FACS) analysis showed that ganglioside depletion only slightly and in the opposite direction affected Pgp- and MRP1-mediated efflux activity. Moreover, both effects were marginal compared with those of well-established inhibitors of either MRP1 (i.e., MK571) or Pgp (i.e., GF120918). t-PPPP slightly enhanced cellular sensitivity to vincristine, as determined by 3-[4,5-dimethylthiazol-2-yl]2,5-diphenyl tetrazolium bromide analysis, in both neuroblastoma cell lines, whereas NB-dNJ was without effect. MRP1 expression and its localization in detergent-resistant membranes were not affected by ganglioside depletion. Together, these results show that gangliosides are not relevant to ABC transporter-mediated MDR in neuroblastoma cells.
 ...
PMID:Gangliosides do not affect ABC transporter function in human neuroblastoma cells. 1654 52


1 2 Next >>