Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aneuploidy is a frequent feature in multiple myeloma. Cytogenetic analyses have shown that a 14q+ chromosome resulting from either a t(8;14)(q24;q32) or a t(11;14)(q13;q32) was the most consistent abnormality but no specific chromosomal aberration has been identified in this disease. Bone marrow cells from 121 consecutive patients with multiple myeloma were analyzed cytogenetically by standard banding techniques including RHG, GTG and CBG banding. Cells were cultured for 24-96 h in the presence or in the absence of interleukin-6. Clonal abnormalities were detected in 41 of the 121 patients (34%). A der(16)t(1;16)(q10;p10) abnormality was identified in nine of these 41 patients (22%). Der(16) was identified at diagnosis in five patients, during disease progression in two additional patients, and at the time of a relapse in the two last cases. The t(1;15)(q10;p10) translocation was always unbalanced, resulting in a monosomy 16q in all cases. The CBG banding did not demonstrate dicentric chromosomes and the whole chromosome painting confirmed the der(16). A large number of other chromosomal abnormalities were associated with der(16), including chromosomal rearrangements involving the 8q24 band in five cases. Four of these five cases were Burkitt's-type translocations. This observation suggests that der(16)t(1;16)(q10;p10) could be one of the most frequent chromosomal abnormalities that can be identified in multiple myeloma cells.
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PMID:Der(16)t(1;16)(q10;p10) in multiple myeloma: a new non-random abnormality that is frequently associated with Burkitt's-type translocations. 786 64

The divalent cation selective ionophores A23187 and ionomycin were compared for their effects on the Ca2+ contents, nucleotide contents, and protein synthetic rates of several types of cultured cells. Both ionophores reduced amino acid incorporation by approximately 85% at low concentrations (50-300 nmol/L) in cultured mammalian cells without reducing ATP or GTP contents. At these concentrations A23187 and ionomycin each promoted substantial Ca2+ efflux, whereas at higher concentrations a large influx of the cation was observed. Ca2+ influx occurred at lower ionophore concentrations and to greater extents in C6 glioma and P3X63Ag8 myeloma than in GH3 pituitary cells. The ATP and GTP contents of the cells and their ability to adhere to growth surfaces declined sharply at ionophore concentrations producing increased Ca2+ influx. Prominent reductions of nucleotide contents occurred in EGTA-containing media that were further accentuated by extracellular Ca2+. Ionomycin produced more Ca2+ influx and nucleotide decline than comparable concentrations of A23187. The inhibition of amino acid incorporation and mobilization of cell-associated Ca2+ by ionomycin were readily reversed in GH3 cells by fatty acid-free bovine serum albumin, whereas the effects of A23187 were only partially reversed. Amino acid incorporation was further suppressed by ionophore concentrations depleting nucleotide contents. Mitochondrial uncouplers potentiated Ca2+ accumulation in response to both ionophores. At cytotoxic concentrations Lubrol PX abolished protein synthesis but did not cause Ca2+ influx. Nucleotide depletion at high ionophore concentrations is proposed to result from increased plasmalemmal Ca2+-ATPase activity and dissipation of mitochondrial proton gradients and to cause intracellular Ca2+ accumulation. Increased Ca2+ contents in response to Ca2+ ionophores are proposed as an indicator of ionophore-induced cytotoxicity.
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PMID:Translational suppression by Ca2+ ionophores: reversibility and roles of Ca2+ mobilization, Ca2+ influx, and nucleotide depletion. 873 79

Type I interferons (IFNs-alpha and IFN-beta) bind to a common receptor to exert strong antiproliferative activity on a broad range of cell types, including interleukin-6 (IL-6)-dependent myeloma cells. In this study, we investigated the effect of IFN-beta pretreatment on IL-6-stimulated mitogenic signaling in the human myeloma cell line U266. IL-6 induced transient tyrosine phosphorylation of the IL-6-receptor signal-transducing subunit gp130, the gp130-associated protein tyrosine kinases Jak1,Jak2, and Tyk2, the phosphotyrosine phosphatase PTP1D/Syp, the adaptor protein Shc and the mitogen-activated protein kinase Erk2, and accumulation of GTP-bound p21ras. Prior treatment of U266 cells with IFN-beta downregulated IL-6-induced tyrosine phosphorylation of gp130, Jak2, PTP1D/Syp, Shc, and Erk2, and GTP-loading of p21ras. Further analysis indicated that treatment with IFN-beta disrupted IL-6-induced binding of PTP1D/Syp to gp130 and the adaptor protein Grb2; IFN-beta pretreatment also interfered with IL-6-induced interaction of Shc with Grb2 and a 145-kD tyrosine-phosphorylated protein. These results suggest a novel mechanism whereby type I IFNs interrupt IL-6-promoted mitogenesis of myeloma cells in part by preventing the formation of essential signaling complexes leading to p21ras activation.
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PMID:Interferon-beta interrupts interleukin-6-dependent signaling events in myeloma cells. 897

The enzyme that catalyzes the formation of GDP-L-fucose from GTP and beta-L-fucose-1-phosphate (i.e. GDP-beta-L-fucose pyrophosphorylase, GFPP) was purified about 560-fold from the cytosolic fraction of pig kidney. At this stage, there were still a number of protein bands on SDS gels, but only the 61-kDa band became specifically labeled with the photoaffinity substrate, azido-GDP-L-[32P]fucose. Several peptides from this 61-kDa band were sequenced and these sequences were used for cloning the gene. The cDNA clone yielded high levels of GFPP activity when expressed in myeloma cells and in a baculovirus system, demonstrating that the 61-kDa band is the authentic GFPP. The porcine tissue with highest specific activity for GFPP was kidney, with lung, liver, and pancreas being somewhat lower. GFPP was also found in Chinese hamster ovary, but not Madin-Darby canine kidney cells. Northern analysis showed the mRNA in human spleen, prostate, testis, ovary, small intestine, and colon. GFPP was stable at 4 (o)C in buffer containing 50 mM sucrose, with little loss of activity over a 9-day period. GTP was the best nucleoside triphosphate substrate but significant activity was also observed with ITP and to a lesser extent with ATP. The enzyme was reasonably specific for beta-L-fucose-1-P, but could also utilize alpha-D-arabinose-1-P to produce GDP-alpha-D-arabinose. The product of the reaction with GTP and alpha-L-fucose-1-P was characterized as GDP-beta-L-fucose by a variety of chemical and chromatographic methods.
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PMID:GDP-L-fucose pyrophosphorylase. Purification, cDNA cloning, and properties of the enzyme. 980 72

Ribavirin, a nucleoside, well known as a broad-spectrum antiviral agent, is extensively used in the treatment of hepatitis C infections. Ribavirin inhibits IMP DH (EC 1.1.1.205) activity and reduces cellular GTP concentration. Quercetin, a plant flavonoid, exhibits antineoplastic activity and inhibits PI 4-kinase (EC 2.7.1.67) and PIP 5-kinase (EC 2.7.1.68) activity. Ribavirin and quercetin attack the cell cycle at the G1 and G1/S boundary, respectively. Because they act on different enzyme targets and arrest the cell cycle at different phases, we tested the hypothesis that ribavirin and quercetin might be synergistic in growth inhibition and cytotoxicity. Human myeloma 8226 and human ovarian carcinoma OVCAR-5 cells were studied because in these cells IMP DH activity increased 14- and 20-fold, respectively, and PI 4- and PIP 5-kinase activities were also elevated. In growth inhibition for ribavirin and quercetin in myeloma 8,226 cells IC50s were 40 and 70 microM, respectively. In OVCAR-5 cells in growth inhibition and clonogenic assays for ribavirin IC50 and LC50 of 35 and 23 microM, respectively, were observed. When quercetin was added 24 h after ribavirin, synergistic antiproliferative action was observed in both myeloma 8,226 and OVCAR-5 cells. Synergistic action was also obtained in OVCAR-5 cells in clonogenic assay when ribavirin was combined with quercetin in the sequence described above. The mechanism of action is provided, in part at least, by the synergistic reduction of signal transduction (IP3 concentration) by ribavirin and quercetin. Ribavirin and quercetin in combination might be of interest in the treatment of myeloma and ovarian carcinoma.
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PMID:Ribavirin and quercetin synergistically downregulate signal transduction and are cytotoxic in human ovarian carcinoma cells. 1060 19

Interferons (IFNs) are a family of hormone-like secretory proteins with multiple phenotypical changes, including gene expression and morphological alterations. Earlier studies have shown that IFN-activated Tyk2 kinase physical associates with p95Vav (Vav), a proto-oncogene gene product expressed in hematopoietic cells. Since Tyk2 is a cytoplasmic kinase and Vav is believed to be localized in the nuclear compartment, here we explored the possibility of Vav redistribution in IFN-alpha-activated cells, using the U266 human myeloma cell line as a model system. Using biochemical assays and in situ confocal microscopy, we demonstrate that IFN-alpha treatment triggers a rapid (10 min) translocation of Vav from the nuclear compartment to the cytoplasm. In addition, we also show the existence of IFN-alpha-induced physical interaction between Vav and Ku80, Ku80, and Tyk2, and among Vav, Ku80, and Tyk2 in the cytoplasmic compartment of IFN-stimulated cells. The observed IFN-alpha-induced association among Vav, Ku80, and Tyk2 was dependent on cellular tyrosine kinase activity. Since recently Vav has been shown to promote the GDP/GTP exchange activity of the cytoskeleton signaling molecule small GTPase Rac1 and activates its downstream signaling, our present findings raise the possibility of involvement of the small GTPase in IFN signaling leading to its biological effects, including cytoskeleton reorganization.
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PMID:Interferon-alpha signaling promotes nucleus-to-cytoplasmic redistribution of p95Vav, and formation of a multisubunit complex involving Vav, Ku80, and Tyk2. 1067 53

Hematological disorders often have complex karyotypes with multiple markers. Proper assignment of chromosome number or aberration or both can be difficult. Specific identification of chromosomal abnormalities aids in the diagnosis and selection of treatment of patients. Fluorescence in situ hybridization (FISH) has been applied to the identification of translocations, markers, and other chromosomal abnormalities in clinical cytogenetics. However, the standard FISH technique is unable to detect the entire genome in a single experiment. This report presents the use of a cross-species comparative genomic hybridization color-banding technique (RxFISH) that permits examination of an entire karyotype at one time. Specimens from two patients, one with acute lymphocytic leukemia (ALL) and the other with multiple myeloma (MM), were studied. Metaphases were prepared by standard culture techniques. Conventional cytogenetic analysis (GTG banding) showed multiple clones in each of the cases. These clones were hyperdiploid metaphases with complex chromosomal abnormalities and multiple markers. The slides were then hybridized with FITC-, Cy-3-, and Cy-5-labeled RxFISH probes; the results were analyzed by a digital imaging system. The RxFISH color banding confirmed the hyperdiploid metaphases and identified multiple chromosomal abnormalities. In the specimen from the patient with ALL, several chromosomes, which had been classified as markers by G-banding, were found to be specific chromosomes. This study suggests that RxFISH can provide more accurate and specific identification of complex chromosomal abnormalities. RxFISH is a useful complement to the clinical cytogenetic laboratory armamentarium.
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PMID:Enhanced detection of chromosomal abnormalities with the use of RxFISH multicolor banding technique. 1074 90

We previously reported the isolation of the novel human DENN gene, which is differentially expressed in normal and neoplastic cells. DENN is identical to MADD (mitogen-activated protein kinase-activating death domain), which interacts with tumor necrosis factor receptor 1 through their death domains. DENN is also homologous to Rab3 GEP, a rat Rab3 GDP/GTP exchange protein. Real-time reverse transcription-polymerase chain reaction analysis showed that DENN expression in cancer cell lines was 26-50 times that in normal cells. The Jurkat human leukemia, PLC/PRF/5 human hepatoma, and NS-1 mouse myeloma cell lines as well as the MRC-5 human fetal lung and Vero monkey kidney cell lines were treated successfully with four separate DENN-targeted antisense oligodeoxynucleotides (ODNs) to abrogate DENN expression. Quantitative assessment of cell viability and apoptosis by flow cytometry via fluorescein diacetate and propidium iodide membrane-integrity tests, terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate-biotin nick end-labeling, and annexin V assays showed that antisense silencing of DENN resulted in markedly more pronounced cell death in cancer cells compared with nonmalignant cells. Antisense-treated cell lines exhibited extensive loss of DNA content, forming distinct sub-G(1) peaks, while cell proliferation diminished significantly. Ultrastructural features of programmed cell death in cells subjected to antisense ODNs were authenticated by electron microscopy. In contrast, transfection of cell lines with a plasmid construct to achieve DENN overexpression augmented cellular proliferation and could reverse the apoptotic effect of antisense and staurosporine treatment. Our findings suggest that DENN is intimately involved in anti-apoptotic and cell-survival processes.
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PMID:Induction of marked apoptosis in mammalian cancer cell lines by antisense DNA treatment to abolish expression of DENN (differentially expressed in normal and neoplastic cells). 1241 May 63

Ras is a major signaling molecule activated by interleukin-6. There have been no published reports, however, that specifically examine the kinetics and percentage of Ras activation in response to IL-6. Model cell lines were used to study activation of N- and K-ras induced by IL-6. All of the myeloma cell lines we tested express both N-ras and K-ras, but not H-ras. GTP-bound Ras was measured and the percentage of the total Ras pool that was activated in response to IL-6 was calculated. IL-6 is able to transiently activate both N- and K-ras in the ANBL6 cell line. In addition, increasing concentrations of IL-6 are able to activate increasing levels of both N- and K-ras. One ng/ml of IL-6 is able to activate approximately 10% of the N-ras pool and 18% of the K-ras pool. The amount of Ras-GTP in the cells correlates with the level of proliferation at low levels, but proliferation plateaus when higher levels of Ras-GTP are present. Protection from dexamethasone-induced apoptosis correlates with IL-6 concentration and Ras activation. However, IL-6 enhances apoptosis induced by doxorubicin. Interestingly, the ANBL6 cell line transfected with an N-ras12 or a K-ras12 gene is protected from doxorubicin-induced apoptosis.
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PMID:Activation of N-ras and K-ras induced by interleukin-6 in a myeloma cell line: implications for disease progression and therapeutic response. 1248 30

Multiple myeloma (MM) is an incurable plasma cell malignancy. To investigate biochemical lesions associated with MM, we constructed an expression cDNA library from the OPM-2 human myeloma line. A highly transforming H-Ras mutant was identified by transfection analysis using NIH 3T3 cells. DNA sequencing demonstrated a single-point mutation at position 117 located in the guanine nucleotide-binding site resulting in a lysine-to-glutamic acid substitution. This mutant, H-Ras (K117E), was found to be constitutively activated in terms of GTP binding. We compared the biological effects of H-Ras (K117E) and H-Ras (G12V) in 32D murine hematopoietic progenitor cells. Whereas both Ras proteins are constitutively activated, 32D cells expressing H-Ras (G12V) are still dependent on IL-3 for survival and proliferation while cells carrying H-Ras (K117E) become IL-3 independent. Similar experiments conducted with the B9 line, an IL-6-dependent hybridoma, also demonstrated that B9/H-Ras (K117E) became IL-6-independent. Expression of H-Ras (K117E) in the human IL-6-dependent ANBL-6 myeloma line resulted in enhanced proliferation at suboptimal concentrations of IL-6. These observations suggest that H-Ras mutations at the binding site for the GTP nucleotide ring structure may also represent activating lesions and have additional biological effects when compared to previously described Ras mutants.
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PMID:An unusual H-Ras mutant isolated from a human multiple myeloma line leads to transformation and factor-independent cell growth. 1256 57


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