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

The poor selective toxicity of chemotherapeutic anticancer drugs leads to dose-limiting side effects that compromise clinical outcome. Solid tumors recruit new blood vessels to support tumor growth, and unique epitopes expressed on tumor endothelial cells can function as targets for the anti-angiogenic therapy of cancer. An NGR peptide that targets aminopeptidase N, a marker of angiogenic endothelial cells, was coupled to the surface of liposomal doxorubicin (NGR-SL[DXR]) and was used to treat orthotopic neuroblastoma (NB) xenografts in SCID mice. Pharmacokinetic studies indicated that liposomes coupled to NGR peptide had long-circulating profiles in blood. Their uptake into NB tumor was time dependent, being at least 10 times higher than that of nontargeted liposomes (SL[DXR]) after 24 h, with DXR spreading outside the blood vessels and into the tumors. No uptake was observed into tumors of mice treated with the mismatched peptide ARA-targeted SL[DXR]. Tumor-specific DXR uptake was completely blocked when mice were coinjected with a 50-fold molar excess of the soluble NGR peptide. Adrenal tumor-bearing mice treated with 2 mg/kg/week/x3 of NGR-SL[DXR] partly outlived the control mice (P < 0.001), whereas doses > 3 mg/kg/week/x3 were toxic. Histopathological analysis of cryosections taken from treated mice revealed pronounced destruction of the tumor vasculature with a marked decreased in vessel density. Double staining of tumors with terminal deoxynucleotidyl transferase-mediated nick end labeling and antifactor VIII antibody or antihuman NB demonstrated endothelial cell apoptosis in the vasculature, as well as increased tumor cell apoptosis. Moreover, mice injected with 3 mg/kg/week/x3 of NGR-SL[DXR] displayed rapid tumor regression, as well as inhibition of metastases growth (P = 0.0002). One day after the third treatment, four of six mice showed no evidence of tumors, and the two others showed a >80% reduction in tumor mass and a >90% suppression of blood vessel density (P < 0.01). In contrast, mice treated with ARA-SL[DXR] formed large well-vascularized tumors. Finally, a metronomic administration of NGR-SL[DXR] (1 mg/kg/every other 2 days x 9) induced complete tumor eradication in all animals (P < 0.0001). Our strategy markedly enhanced the therapeutic index of DXR and enabled metronomic administration of therapeutic doses. A dual mechanism of action is proposed: indirect tumor cell kill via the destruction of tumor endothelium by NGR-targeted liposomes and direct tumor cell kill via localization of liposomal DXR to the tumor interstitial space. This combined strategy has the potential to overcome some major limitations of conventional chemotherapy.
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PMID:Vascular damage and anti-angiogenic effects of tumor vessel-targeted liposomal chemotherapy. 1461 39

The central nervous system myelin components oligodendrocyte-myelin glycoprotein, myelin-associated glycoprotein and the Nogo-66 domain of Nogo-A inhibit neurite outgrowth by binding the neuronal glycosyl-phosphatidylinositol-anchored Nogo-66 receptor (NgR) that transduces the inhibitory signal to the cell interior via a transmembrane co-receptor, p75NTR. Here, we demonstrate that human NgR expressed in human neuroblastoma cells is constitutively cleaved in a post-ER compartment to generate a lipid-raft associated C-terminal fragment that is present on the cell surface and a soluble N-terminal fragment that is released into the medium. Mass spectrometric analysis demonstrated that the N-terminal fragment terminated just after the C-terminus of the ligand-binding domain of NgR. In common with other shedding mechanisms, the release of this fragment was blocked by a hydroxamate-based inhibitor of zinc metalloproteinases, but not by inhibitors of other protease classes and up-regulated by treatment with the cellular cholesterol depleting agent methyl-beta-cyclodextrin. The N-terminal fragment bound Nogo-66 and blocked Nogo-66 binding to cell surface NgR but failed to associate with p75NTR, indicative of a role as a Nogo-66 antagonist. Furthermore, the N- and C-terminal fragments of NgR were detectable in human brain cortex and the N-terminal fragment was also present in human cerebrospinal fluid, demonstrating that NgR proteolysis occurs within the human nervous system. Our findings thus identify a potential cellular mechanism for the regulation of NgR function at the level of the receptor.
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PMID:Zinc metalloproteinase-mediated cleavage of the human Nogo-66 receptor. 1533 67

The Nogo-66 receptor (NgR) plays a pivotal role in the inhibition of neuroregeneration as the receptor for multiple neurite outgrowth inhibitors such as Nogo-A. We have previously shown that NgR undergoes zinc metalloproteinase-mediated ectodomain shedding in neuroblastoma cells. Here, we demonstrate that the NgR-related protein NgR homologue-1 is released from neuroblastoma cells as a full-length ectodomain (NgRH1-ecto) and an N-terminal fragment (NTF-NgRH1) containing the leucine-rich repeat region of the protein. Inhibitors of the major protease classes failed to block the release of NgRH1-ecto, suggesting that this occurs via a protease-independent mechanism, presumably by a phospholipase-like enzyme. The release of NTF-NgRH1 was blocked by a hydroxamate-based zinc metalloproteinase inhibitor and tissue inhibitor of metalloproteinases-2 and -3, but not -1, implicating the involvement of membrane-type matrix metalloproteinases in this process. Our findings thus highlight the parallels between the ectodomain shedding of NgRH1 and that previously described for NgR.
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PMID:Ectodomain shedding of human Nogo-66 receptor homologue-1 by zinc metalloproteinases. 1562 37

The poor selectivity of chemotherapeutic drugs for neoplastic cells may lead to dose-limiting side effects that compromise clinical outcomes. Moreover, heterogeneous tumor perfusion and vascular permeability, and increased interstitial pressure, could represent critical barriers that limit the penetration of drugs into neoplastic cells distant from tumor vessels and, consequently, the effectiveness of chemotherapy. We have recently developed two strategies for increasing the local concentration of chemotherapeutic drugs in tumors and their therapeutic index, based on tumor vascular targeting. First, we have found that vascular targeting with minute amounts of tumor necrosis factor alpha (TNF-alpha), an inflammatory cytokine able to increase vascular permeability, alters tumor barriers and increases the penetration of chemotherapeutic drugs in subcutaneous tumors in mouse models. Targeted delivery of TNF-alpha to tumor vessels was achieved by coupling this cytokine with cyclic CNGRC peptide, an aminopeptidase N (CD13) ligand that targets the tumor neovasculature. Second, we have observed that encapsulation of doxorubicin into liposomes able to home to tumor vessels markedly improves drug uptake by neuroblastoma tumors, in an orthotopic xenograft model, and its therapeutic index. Targeted delivery of liposomes was achieved by coupling linear GNGRG peptide to the surface of liposomal doxorubicin. Vascular targeting, either indirectly with NGR-TNF-alpha or directly with NGR-targeted liposomes, could be a novel strategy for increasing the therapeutic index of chemotherapeutic drugs.
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PMID:Tumor vascular targeting with tumor necrosis factor alpha and chemotherapeutic drugs. 1565 Feb 36

Pathophysiologic hypotheses for Alzheimer's disease (AD) are centered on the role of the amyloid plaque Abeta peptide and the mechanism of its derivation from the amyloid precursor protein (APP). As part of the disease process, an aberrant axonal sprouting response is known to occur near Abeta deposits. A Nogo to Nogo-66 receptor (NgR) pathway contributes to determining the ability of adult CNS axons to extend after traumatic injuries. Here, we consider the potential role of NgR mechanisms in AD. Both Nogo and NgR are mislocalized in AD brain samples. APP physically associates with the NgR. Overexpression of NgR decreases Abeta production in neuroblastoma culture, and targeted disruption of NgR expression increases transgenic mouse brain Abeta levels, Abeta plaque deposition, and dystrophic neurites. Infusion of a soluble NgR fragment reduces Abeta levels, amyloid plaque deposits, and dystrophic neurites in a mouse transgenic AD model. Changes in NgR level produce parallel changes in secreted APPalpha and Abeta, implicating NgR as a blocker of secretase processing of APP. The NgR provides a novel site for modifying the course of AD and highlights the role of axonal dysfunction in the disease.
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PMID:Alzheimer precursor protein interaction with the Nogo-66 receptor reduces amyloid-beta plaque deposition. 1645 62

Neuroblastoma, the most common solid tumor of infancy derived from the sympathetic nervous system, continues to present a formidable clinical challenge. Sterically stabilized immunoliposomes (SIL) have been shown to enhance the selective localization of entrapped drugs to solid tumors, with improvements in therapeutic indices. We showed that SIL loaded with doxorubicin (DXR) and targeted to the disialoganglioside receptor GD(2) [aGD(2)-SIL(DXR)] led to a selective inhibition of the metastatic growth of experimental models of human neuroblastoma. By coupling NGR peptides that target the angiogenic endothelial cell marker aminopeptidase N to the surface of DXR-loaded liposomes [NGR-SL(DXR)], we obtained tumor regression, pronounced destruction of the tumor vasculature, and prolonged survival of orthotopic neuroblastoma xenografts. Here, we showed good liposome stability, long circulation times, and enhanced time-dependent tumor accumulation of both the carrier and the drug. Antivascular effects against animal models of lung and ovarian cancer were shown for formulations of NGR-SL(DXR). In the chick embryo chorioallantoic assay, NGR-SL(DXR) substantially reduced the angiogenic potential of various neuroblastoma xenografts, with synergistic inhibition observed for the combination of NGR-SL(DXR) with aGD(2)-SIL(DXR). A significant improvement in antitumor effects was seen in neuroblastoma-bearing animal models when treated with the combined formulations compared with control mice or mice treated with either tumor- or vascular-targeted liposomal formulations, administered separately. The combined treatment resulted in a dramatic inhibition of tumor endothelial cell density. Long-term survivors were obtained only in animals treated with the combined tumor- and vascular-targeted formulations, confirming the pivotal role of combination therapies in treating aggressive metastatic neuroblastoma.
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PMID:Targeting liposomal chemotherapy via both tumor cell-specific and tumor vasculature-specific ligands potentiates therapeutic efficacy. 1704 71

Nogo-66 receptor 1 (NgR1) is a glycosylphosphatidylinositol-anchored receptor for myelin-associated inhibitors that restricts plasticity and axonal regrowth in the CNS. NgR1 is cleaved from the cell surface of SH-SY5Y neuroblastoma cells in a metalloproteinase-dependent manner; however, the mechanism and physiological consequence of NgR1 shedding have not been explored. We now demonstrate that NgR1 is shed from multiple populations of primary neurons. Through a loss-of-function approach, we found that membrane-type matrix metalloproteinase-3 (MT3-MMP) regulates endogenous NgR1 shedding in primary neurons. Neuronal knockdown of MT3-MMP resulted in the accumulation of NgR1 at the cell surface and reduced the accumulation of the NgR1 cleavage fragment in medium conditioned by cortical neurons. Recombinant MT1-, MT2-, MT3-, and MT5-MMPs promoted NgR1 shedding from the surface of primary neurons, and this treatment rendered neurons resistant to myelin-associated inhibitors. Introduction of a cleavage-resistant form of NgR1 reconstitutes the neuronal response to these inhibitors, demonstrating that specific metalloproteinases attenuate neuronal responses to myelin in an NgR1-dependent manner.
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PMID:Membrane-type matrix metalloproteinase-3 regulates neuronal responsiveness to myelin through Nogo-66 receptor 1 cleavage. 2176 85

Neuroblastoma is an embryonal tumor originating from the simpatico-adrenal lineage of the neural crest. It approximately accounts for about 15% of all pediatric oncology deaths. Despite advances in multimodal therapy, metastatic neuroblastoma tumors at diagnosis remain a clinical challenge. Retinoids are a class of compounds known to induce both terminal differentiation and apoptosis/necrosis of neuroblastoma cells. Among them, fenretinide (HPR) has been considered one of the most promising anti-tumor agent but it is partially efficacious due to both poor aqueous solubility and rapid metabolism. Here, we have developed a novel HPR formulation, by which the drug was encapsulated into sterically stabilized nanoliposomes (NL[HPR]) according to the Reverse Phase Evaporation method. This procedure led to a higher structural integrity of liposomes in organic fluids for a longer period of time, in comparison with our previous liposomal formulation developed by the film method. Moreover, NL[HPR] were further coupled with NGR peptides for targeting the tumor endothelial cell marker, aminopeptidase N (NGR-NL[HPR]). Orthotopically xenografted neuroblastoma-bearing mice treated with NGR-NL[HPR] lived statistically longer than mice untreated or treated with free HPR (NGR-NL[HPR] vs both control and HPR: P<0.0001). Also, NL[HPR] resulted in a statistically improved survival (NL[HPR] vs both control and HPR: P<0.001) but to a less extent if compared with that obtained with NGR-NL[HPR] (NGR-NL[HPR] vs NL[HPR]: P<0.01). Staining of tumor sections with antibodies specific for neuroblastoma and for either pericytes or endothelial cells evidenced that HPR reduced neuroblastoma growth through both anti-tumor and anti-angiogenic effects, mainly when delivered by NGR-NL[HPR]. Indeed, in this group of mice a marked reduction of tumor progression, of intra-tumoral vessel counts and VEGF expression, together with a marked down-modulation of matrix metalloproteinases MMP2 and MMP9, was observed. In conclusion, the use of this novel targeted delivery system for the apoptotic and antiangiogenic drug, fenretinide, could be considered as an adjuvant tool in the future treatment of neuroblastoma patients.
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PMID:Enhanced anti-tumor and anti-angiogenic efficacy of a novel liposomal fenretinide on human neuroblastoma. 2379 18

Neuroblastoma (NB) is the most common extracranial solid tumor in children, accounting for about 8% of childhood cancers. Despite aggressive treatment, patients suffering from high-risk NB have very poor 5-year overall survival rate, due to relapsed and/or treatment-resistant tumors. A further increase in therapeutic dose intensity is not feasible, because it will lead to prohibitive short-term and long-term toxicities. New approaches with targeted therapies may improve efficacy and decrease toxicity. The use of drug delivery systems allows site specific delivery of higher payload of active agents associated with lower systemic toxicity compared to the use of conventional ("free") drugs. The possibility of imparting selectivity to the carriers to the cancer foci through the use of a targeting moiety (e.g., a peptide or an antibody) further enhances drug efficacy and safety. We have recently developed two strategies for increasing local concentration of anti-cancer agents, such as CpG-containing oligonucleotides, small interfering RNAs, and chemotherapeutics in NB. For doing that, we have used the monoclonal antibody anti-disialoganglioside (GD2), able to specifically recognize the NB tumor and the peptides containing NGR and CPRECES motifs, that selectively bind to the aminopeptidase N-expressing endothelial and the aminopeptidase A-expressing perivascular tumor cells, respectively. The review will focus on the use of tumor- and tumor vasculature-targeted nanocarriers to improve tumor targeting, uptake, and penetration of drugs in preclinical models of human NB.
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PMID:Nanocarrier-mediated targeting of tumor and tumor vascular cells improves uptake and penetration of drugs into neuroblastoma. 2393 62

Neuroblastoma is a childhood cancer with poor long-term prognosis in advanced stages. A major aim in neuroblastoma therapy is to develop targeted drug delivery systems to ameliorate drug therapeutic index and efficacy. In this study, a novel bortezomib (BTZ) liposomal formulation was set-up and characterized. Since BTZ is freely permeable across the lipidic bilayer, an amino-lactose (LM) was synthesized as complexing agent to entrap BTZ inside the internal aqueous compartment of stealth liposomes. High encapsulation efficiency was achieved by a loading method based on the formation of boronic esters between the boronic acid moiety of BTZ and the hydroxyl groups of LM. Next, NGR peptides were linked to the liposome surface as a targeting-ligand for the tumor endothelial cell marker, aminopeptidase N. Liposomes were characterized for size, Z-potential, polydispersity index, drug content, and release. Lyophilization in the presence of cryoprotectants (trehalose, sucrose) was also examined in terms of particle size changes and drug leakage. BTZ was successfully loaded into non-targeted (SL[LM-BTZ]) and targeted (NGR-SL[LM-BTZ]) liposomes with an entrapment efficiency of about 68% and 57%, respectively. These nanoparticles were suitable for intravenous administration, presenting an average diameter of 170nm and narrow polydispersity. Therefore, orthotopic NB-bearing mice were treated with 1.0 or 1.5mg/kg of BTZ, either in free form or encapsulated into liposomes. BTZ loaded liposomes showed a significant reduction of drug systemic adverse effects with respect to free drug, even at the highest dose tested. Moreover, mice treated with 1.5mg/kg of NGR-SL[LM-BTZ] lived statistically longer than untreated mice (P=0.0018) and SL[LM-BTZ]-treated mice (P=0.0256). Our results demonstrate that the novel vascular targeted BTZ formulation is endowed with high therapeutic index and low toxicity, providing a new tool for future applications in neuroblastoma clinical studies.
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PMID:Tumor vascular targeted liposomal-bortezomib minimizes side effects and increases therapeutic activity in human neuroblastoma. 2603 42


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