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)

Op18 is a highly conserved major cytosolic phosphoprotein that is expressed at high levels in acute leukemia and in neuroblastoma. In this study we present evidence pointing to a role for Op18 in cellular proliferation. Blocking of Op18 mRNA translation using antisense oligonucleotides delayed entrance of mitotically stimulated normal peripheral blood lymphocytes into the S phase. Moreover treatment of HL-60 promyelocytic leukemia cells with DMSO or PMA which induced terminal differentiation resulted in a decrease in the level of Op18 RNA and protein. Inhibition of lymphoid proliferation with cyclosporin also resulted in reduced Op18 levels.
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PMID:Involvement of OP18 in cell proliferation. 193 Feb 3

Several studies have shown that neuroblastoma and retinoblastoma tumor cells often have elevated N-myc mRNA levels compared to normal adult neuronal or retinal tissues, and it has been suggested that increased expression of this protooncogene may play an important role in tumorigenesis or malignant progression in cells of neural origin. We have studied the effect of protein synthesis inhibitors on the N-myc mRNA levels in Y79 retinoblastoma and LA-N-5 neuroblastoma cells. We showed that when new RNA synthesis was inhibited by actinomycin D the levels of existing N-myc mRNA fell rapidly in both cell lines relative to total cytoplasmic RNA. The half-life for N-myc mRNA was approximately 30 min. Inhibition of protein synthesis by interfering with polypeptide elongation or by inhibiting initiation of protein synthesis increased the levels of N-myc mRNA at least 3-fold after 4 hours. Nuclear runoff transcription experiments showed that the protein synthesis inhibitors did not alter N-myc transcription rates. Combined actinomycin D treatment and treatment with protein synthesis inhibitors indicated that this increase in N-myc transcript levels was due to an increase in the N-myc mRNA lifetimes. Thus, N-myc transcript levels increased because they were more stable in protein synthesis-inhibited cells. Protein synthesis inhibition also increased c-myc mRNA levels in HL-60 human promyelocytic leukemia cells, but no increase was seen in the relatively low level of c-myc mRNA in protein synthesis-inhibited neuronal tumor cells. These results support the hypothesis that the regulation of N-myc in these neuronal and retinal tumor cells is similar to that of c-myc in other tumor types.
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PMID:Regulation of N-myc transcript stability in human neuroblastoma and retinoblastoma cells. 244 70

The venoms of the Naja species are known to be cytotoxic. This toxicity has been attributed to the presence of small nonenzymatic polypeptides of 60 amino acid residues, designated as cardiotoxins or cytotoxins. We investigated the cytotoxic potency of Naja nigricollis venom fractions and isolated another type of cytotoxic component which is even more potent than cardiotoxins. This cytotoxic compound, which was designated as nigexine, was purified to homogeneity and its amino acid sequence was determined. Nigexine is a basic phospholipase A2 consisting of a single chain of 118 amino acids. A detailed investigation of the cytotoxic effects on epithelial FL cells, C-13T neuroblastoma cells, and promyelocytic leukemia HL 60 cells revealed that nigexine not only altered cell viability but also prevented cell proliferation. This is a property that was specific to nigexine since other phospholipases A2 from various sources had no detectable cytotoxic activity. The cytotoxic activity of nigexine was not dependent on the presence of divalent cations, unlike its enzymatic activity. In particular, the cytotoxic activity of nigexine was identical in the presence or absence of either 2 mM Ca2+ or Sr2+, or 6 mM EDTA. We also present evidence based on chemical modifications that cytotoxic activity was not correlated with enzymatic activity. Thus, modification with parabromophenacyl bromide totally abolished the enzymatic activity of nigexine, which nevertheless retained 6-20% of the cytotoxicity of native nigexine. Conversely, treatment with cyanogen bromide gave a compound that retained 7% of the enzymatic activity of the parent molecule but was devoid of detectable cytotoxicity.
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PMID:Nigexine, a phospholipase A2 from cobra venom with cytotoxic properties not related to esterase activity. Purification, amino acid sequence, and biological properties. 275 14

In several recent reviews, we have suggested that the mechanism of action of retinoids in controlling cell differentiation is related to their effects on the expression of oncogenes and peptide growth factors. It is currently believed that oncogenes control metabolic pathways that involve peptide growth factors and their receptors, as well as postreceptor signaling mechanisms. Retinoids, therefore, have been valuable probes to study the function of oncogenes and peptide growth factors. In several tumor cells, including human promyelocytic leukemia, human and murine neuroblastoma, and murine teratocarcinoma, retinoic acid induces terminal differentiation, accompanied by suppression of the expression of either the c-myc or the N-myc gene. Many studies have indicated that retinoic acid can markedly increase the number of cellular receptors for epidermal growth factor, which is partially encoded by another oncogene, erb-B. We have shown that retinoic acid greatly inhibits the anchorage-independent growth of a rat fibroblast cell line that has been transfected with the c-myc gene, particularly when these cells are stimulated by the combination of platelet-derived growth factor and transforming growth factor-beta. At present, the mechanisms by which retinoids control oncogene and growth factor expression are unknown. A wide range of new compounds, including the retinoidal benzoic acid derivatives, are now available to study these mechanisms, and will necessitate the identification of a high-affinity receptor for retinoids and the elucidation of the interaction of this receptor with the genome of the cell. The recent synthesis of new terephthalic acid anilides and chalcone carboxylic acid derivatives, which have retinoid-like activity, offers a particularly useful approach to this problem.
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PMID:Mechanism of action of retinoids. 302 29

The ret transforming gene was activated by recombination between two unlinked segments of human DNA, most likely during transfection of NIH 3T3 cells. To further define this transforming gene, we isolated and sequenced ret cDNA clones. The nucleotide sequence indicates that the active ret transforming gene encodes a fusion protein with a carboxy-terminal domain which is 40 to 50% homologous to members of the tyrosine kinase gene family. This tyrosine kinase domain is preceded by a hydrophobic sequence characteristic of a transmembrane domain. Transcription of the ret tyrosine kinase sequence was detected in the SK-N-SH neuroblastoma, HL-60 promyelocytic leukemia, and THP-1 monocytic leukemia cell lines, but not in 25 other human tumor cell lines surveyed. The ret tyrosine kinase may thus represent a cell surface receptor which is expressed in a restricted range of human cells.
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PMID:ret transforming gene encodes a fusion protein homologous to tyrosine kinases. 303 15

Platelet aggregating activity of the NCG human neuroblastoma cell line was compared with that of the HL-60 human promyelocytic leukemia cell line. NCG, in intact cell suspensions and ultracentrifuged pellets, induced platelet aggregation most significantly in heparinized platelet rich plasma (PRP) containing 2.5 units/ml of heparin, but not in the presence of higher concentrations of heparin or 5 mM ethylenediamine-tetraacetate or in citrated PRP. NCG induced platelet aggregation was also inhibited by hirudin or (2R,4R)-4-methyl-1-[N2-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfon yl)-L- arginyl]-2-piperidinecarboxylic acid (MD 805) in the same manner as that of tissue thromboplastin induced platelet aggregation. HL-60 cells did not induce platelet aggregation in our heparinized PRP assay systems; however, after treatment with neuraminidase HL-60 cells became active in aggregating platelets in either heparinized or citrated PRP. NCG demonstrated high procoagulant activity by either intact cell suspensions or ultracentrifuged pellets. The procoagulant activity of NCG was reduced in Factor VII deficient human plasma as it was in the results obtained by tissue thromboplastin. These results suggest that NCG induces platelet aggregation via thrombin generated through procoagulant activity which is shed in association with microvesicles demonstrated in the ultracentrifuged pellets. This type of platelet aggregating activity found in NCG is significantly different from that of HL-60.
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PMID:Platelet aggregating activity mediated by thrombin generation in the NCG human neuroblastoma cell line. 382 2

The anticonvulsant drug 1-methyl-1-cyclohexanecarboxylic acid ( MCCA ) has been shown to cause maturation of murine neuroblastoma cells in vitro at concentrations that are pharmacologically achievable. HL-60 human promyelocytic leukemia cells cultured with this drug underwent a dose-dependent decrease in growth. Similarly, neutrophilic differentiation, based on morphologic criteria and the acquisition of the ability to reduce nitroblue tetrazolium and phagocytose yeast, was observed. Valproic acid, a clinically available anticonvulsant that is chemically related to MCCA , likewise inhibited growth and promoted maturation of HL-60 cells, although only at concentrations above the recommended therapeutic blood levels. MCCA was additive in its ability to induce differentiation of HL-60 with retinoic acid, another compound that induces differentiation at pharmacologic concentrations. MCCA , or similar branched-chain fatty acids, may be useful in the treatment of human leukemia, particularly in combination with other differentiation-inducing drugs.
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PMID:Induction of neutrophilic differentiation of human promyelocytic leukemic cells by branched-chain carboxylic acid anticonvulsant drugs. 642 13

A human neuroblastoma cell line (Paju) was resistant to 10 mM difluoromethylornithine, a concentration at which the growth of all mammalian cells normally stops. Ornithine decarboxylase from Paju was very resistant to inhibition by difluoromethylornithine in vitro (Ki = 10 microM compared to 0.5 microM for mouse kidney ornithine decarboxylase). After purification, apparently homogeneous Paju ornithine decarboxylase was inactivated with [3H]difluoromethylornithine and analyzed by polyacrylamide gel electrophoresis. Under denaturing conditions it was found to have an altered molecular structure, i.e. two nonidentical subunits of Mr = 55,000 and 60,000. Another unusual feature of Paju ornithine decarboxylase was its long half-life in vivo (T 1/2 = 8 h compared with 36 min in human HL-60 promyelocytic leukemia cells). The disappearance of immunoreactive protein was only slightly slower than the loss of catalytic activity. The long half-life of Paju ornithine decarboxylase was not shared by adenosylmethionine decarboxylase. Despite the altered structure of Paju ornithine decarboxylase, it was recognized by a specific antisera raised in rabbit against mouse kidney ornithine decarboxylase. The Paju karyotype did not contain double minute chromosomes or any large homogeneously staining region such as that seen in a mouse lymphoma cell mutant that is resistant to difluoromethylornithine and overproduces ornithine decarboxylase (McConlogue, L., and Coffino, P. (1983) J. Biol. Chem. 258, 12083-12086).
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PMID:A human neuroblastoma cell line with an altered ornithine decarboxylase. 643 32

The oncogene of the HL-60 human promyelocytic leukemia cell line has been passed serially through NIH/3T3 mouse fibroblasts. Oncogene-specific probes prepared from the resulting tertiary transfectants by molecular cloning have been used to show that loss of the transfected oncogene from NIH/3T3 cells correlates with reversion to nontransformed morphology. Analysis of cells transfected by the oncogenes of other tumors and tumor cell lines indicates that the transforming gene of the HL-60 leukemia cell line is closely related to oncogenes of a Burkitt's lymphoma, an acute myelogenous leukemia, an adenocarcinoma of the colon, a neuroblastoma, and two sarcomas. This oncogene is distantly related to the viral oncogenes of Kirsten and Harvey sarcoma viruses. It has been termed N-ras. The active N-ras oncogene coexists with altered versions of the myc oncogene in the HL-60 and AW Ramos human tumors. This suggests a multistep mechanism involving both ras and myc genes in the creation of these tumors.
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PMID:The HL-60 transforming sequence: a ras oncogene coexisting with altered myc genes in hematopoietic tumors. 668 94

Telomerase, the enzyme that maintains the ends of linear eukaryotic chromosomes, is active in human germ cells and in a majority of tumor tissues and immortalized cell lines. In contrast, most mature somatic cells and tissues contain low or undetectable telomerase activity, implying a stringent negative regulatory control mechanism. We report here that telomerase activity is dramatically inhibited during the terminal differentiation of HL-60 human promyelocytic leukemia cells to monocytic and granulocytic lineages. A loss of telomerase activity was seen in response to three different inducers of differentiation, was independent of differentiation-induced apoptosis, and occurred in the presence of unaltered expression of the RNA component of telomerase. Reduction in telomerase activity was also observed during the differentiation of murine F9 teratocarcinoma and C2C12 myoblast cells. In contrast, induced differentiation of murine p19 embryonal carcinoma and Neuro 2a neuroblastoma cells did not result in a loss of telomerase activity. These results are therefore consistent with the absence of telomerase activity in human somatic cells and the presence of telomerase activity in many somatic murine cells and tissues.
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PMID:Selective inhibition of telomerase activity during terminal differentiation of immortal cell lines. 870 26


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