Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Beta 2-microglobulin-bound T-cell membrane components containing both human TL-like antigens and HLA(A, B, C) antigens were partially purified from Renex 30-solubilized membrane material of cells of a human T-cell-type leukemia cell line, HPB-ALL. The radioiodinated preparation was subjected to limited papain digestion; the HLA(A, B, C) antigens split, whereas a large portion of the human TL-like antigens remained intact. The antigen molecules were recovered by lentil-lectin affinity chromatography and separated by gel filtration on the basis of the induced difference in molecular size. The human TL-like-antigen preparation thus obtained was essentially free of HLA(A, B, C) antigens. The human TL-like antigens were immunospecifically precipitated and the component polypeptide, heavy and light, chains were separated by acid dissociation followed by gel filtration. The component chains were compared with the corresponding chains of HLA(A, B, C) antigens obtained similarly from the same HPB-ALL cells with respect to their fragmentation patterns on chemical or enzymatic cleavage. The results provided convincing evidence for the identity of the light chains of human TL-like antigens and HLA(A, B, C) antigens, and also evidence suggesting the presence of substantial differences in the fundamental structure of the heavy chains of human TL-like antigens and HLA(A, B, C) antigens.
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PMID:Separation and comparison of human TL-like antigens and HLA(A, B, C) antigens expressed on cultured T cells. 616 35

Partially purified IgE receptor(s) of rat basophilic leukemia cells (RBL) designated R and H and having apparent molecular weight of 45,000 and 55,000 daltons, respectively, were subjected to proteolysis with papain. Polyacrylamide gel electrophoresis of the digests in the presence of sodium dodecyl sulfate revealed a difference in the size and number of the fragments produced. These results suggest that these two receptor molecules are different with respect to amino acid composition and sequence. Whole Nonidet P-40 extracts of RBL cells were also subjected to digestions with papain, trypsin and chymotrypsin in an attempt to obtain receptor fragments still capable of binding to IgE-Sepharose. Treatment with papain produced a 38,000 dalton fragment of H but no fragments of R which retained the ability to bind to IgE. Tryptic and chymotryptic treatment produced a 41,000 dalton fragment of H with affinity for IgE. The IgE-binding site of R was either destroyed or not affected at all.
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PMID:Proteolytic fragments of the receptors for IgE. 621 Jun 30

5'-Nucleotidase activity of normal human embryonic lung fibroblasts (IMR-90) was found to be inhibited by the homogenates of seven different cell lines originated from patients with different kinds of leukemia and of fresh lymphocytes from a patient with Sezary syndrome (circulating T-cell lymphoma). About 97% of the inhibiting activity was found in the soluble fraction of RPMI 8402 cells, a cell line originated from the lymphocytes of a patient with acute lymphocytic leukemia. This inhibiting activity was not destroyed by dialysis, heating at 56 degrees C for 30 min, nor digestion with RNAase or DNAase. About 85% of the inhibiting activity was destroyed by digestion with papain at 37 degrees C for 1 h and it was destroyed completely by heating at 100 degrees C for 30 min. When the heated (56 degrees C for 30 min) soluble fraction of RPMI 8402 cells was mixed with the homogenate of IMR-90 cells, it had no effect on the activities of alkaline, neutral or acid phosphatases, nor of N-acetyl-beta-D-glucosaminidase or cytochrome c oxidase of IMR-90 cells. Preincubating the mixed samples for 1, 20 and 45 min, respectively, before adding the substrate, the heated soluble fraction of RPMI 8402 cells did not increase the percentage of inhibition for 5'-nucleotidase of the homogenate of IMR-90 cells. No inhibition of other enzyme activities was observed under similar conditions. These data suggest that the inhibiting activity is due to a protein(s) that is not a protease. The inhibiting activity was found in a single peak after the soluble fraction was fractionated by Sephadex G-100 chromatography and sedimentation centrifugation. The molecular weight of the inhibitor was found to be approx. 35,000 by comparing its retention volume and sedimentation rate with those of proteins of known molecular weight. The present study suggest that the previously reported undetectability of 5'-nucleotidase in permanent cell lines could be due to the presence of a protein inhibitor for 5'-nucleotidase in these human leukemic cell lines. It also supports the hypothesis that the increased 5'-nucleotidase activity in normal senescent cells in vitro may be a control in cellular aging that is missing from leukemic cells in vitro.
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PMID:Implications of a 5'-nucleotidase inhibitor in human leukemic cells for cellular aging and cancer. 630 89

Antibodies specific for membrane-associated antigens of human osteosarcoma cells were isolated from sera of 12 patients with osteosarcoma (OS). Affinity columns were prepared by coupling purified membrane antigens from cultured human OS cell lines (TE-85 or LM) to CBrN-activated Sepharose 4B. The antigens were prepared by discontinuous sucrose gradient ultracentrifugation, papain digestion, and DEAE column chromatography. Diluted serum was passed over the affinity columns, and the adsorbed proteins were eluted with 2.5 M MgCl2 (pH 6.5). Immunodiffusion, indirect immunofluorescence, and complement fixation were used to assay antibody activity in the eluate. Specific anti-OS activity was found in the immunoglobulin (Ig) fraction isolated from the sera of the 12 OS patients, as confirmed by blocking experiments. No anti-OS antibody activity was found in sera from healthy individuals or patients with breast carcinoma, clear cell liposarcoma, or leukemia in this study. The anti-OS activity of the isolated Ig from OS patients was abolished after absorption with cultured human OS cells from lines LM, TE-85, or G292 but not after absorption with cells from lines WI-38 (embryonic lung), TE-32 (rhabdomyosarcoma), CAMA-1 or SW527 (breast carcinoma), or M-14 (melanoma). Absorption with rabbit antihuman IgG but not with rabbit antihuman IgM immunobeads completely eliminated the antibody activity.
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PMID:Osteosarcoma patients: isolation of serum antibodies by affinity chromatography. 679 43

The cells of the B lymphocytic leukaemia (L2C) of strain 2 guinea-pigs have IgM on their surfaces but produce insufficient monoclonal IgM in vivo to be detectable by conventional serum electrophoresis. A radioimmunoassay, using anti-idiotypic antibody raised against the surface IgM of these cells, has been used to estimate levels of extracellular IgM produced both in vitro and in vivo. Analyses of the contributions to such IgM from the cell surface and from an export pathway have been made by examining the effect of prior removal of surface Fab mu by papain, and by following the fate of radio-iodinated surface IgM. Results suggest that the extracellular IgM arises predominantly from an export pathway, being exported in both pentameric and monomeric forms. Only a minute contribution, possibly in the form of vesicle-bound monomeric IgM, appears to derive from the cell surface. Radioimmunoassay was used to monitor the increasing levels of this leukaemic cell product during the course of the disease. Idiotypic IgM was detectable when the body load of neoplastic cells was approximately 4% of that detectable by an increased white cell count in the blood.
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PMID:Immunoglobulin produced by guinea-pig leukaemic B lymphocytes: its source and use as a monitor of tumour load. 696 18

Xenoantiserum to human malignant melanoma was prepared by immunizing rabbits with melanoma associated antigens (MAA) solubilized from melanoma cell membrane by limited papain digestion. The antiserum was absorbed extensively with red cells, leukemia cells and cultured lymphoid cell lines, and was assayed for its reactivity with different human cell types by the indirect membrane immunofluorescence and radioimmunoprecipitation techniques. The data obtained suggest that there are at least two different MAA on human melanoma cells. The first is melanoma-group specific and can be detected commonly on different melanoma cell lines. The second is oncofetal and is shared by melanoma, carcinoma, and fetal cells tested thus far. Immunoprecipitated material from melanoma cell membrane that had been radioiodinated with lactoperoxidase and solubilized with a non-ionic detergent was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed two major peaks with estimated molecular weights of 90,000 and 120,000 daltons. The 90,000 molecular weight component appears to be oncofetal, as it disappeared when the antiserum was absorbed with either melanoma or carcinoma cell lines.
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PMID:Surface antigenic characteristics of human melanoma cells defined by xenoantiserum raised against papain-solubilized melanoma-associated antigens. 702 33

Regulation of the expression of major histocompatibility complex (MHC) class I heavy chains not associated with beta 2-microglobulin (beta 2m) on freshly isolated and in vitro cultured human B and T leukemia cells was analyzed. These beta 2m-free class I heavy chains originate from surface beta 2m-associated MHC class I molecules and are expressed as integral membrane glycoproteins on activated, but not resting, cells. We found that the levels of beta 2m-free class I heavy chains can be regulated by proteolytic cleavage and release into the medium of soluble molecules containing the extracellular domains. The release is mediated by a Zn(2+)-dependent, membrane-bound metalloprotease that does not cleave HLA-DR, CD4, and CD71 surface receptors and can be activated by phorbol myristate acetate. Specific cleavage by the metalloprotease occurs at a site close to the papain cleavage site in the alpha 3 domain of class I heavy chains. This site is not accessible to the metalloprotease in beta 2m-associated MHC class I molecules. The dissociation of beta 2m-associated MHC class I molecules and subsequent cleavage of beta 2m-free class I heavy chains may be partially responsible for controlling the levels of MHC class I molecules on the surface of activated cells.
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PMID:Soluble beta 2-microglobulin-free class I heavy chains are released from the surface of activated and leukemia cells by a metalloprotease. 812 26

High-molecular-mass alkaline phosphatase (H-Mr AP) was detected in sera from children with solid tumors without liver metastases. H-Mr AP activities were determined by a liquid chromatographic and an electrophoretic method. In 5 out of 10 cases with solid tumors--Ewing sarcoma (n = 2), neuroblastoma (n = 2), and rhabdoid tumor (n = 1)--H-Mr AP activities ranged from 3.1-40.4 U/L and 3.1-16% of total serum AP activity. In sera of patients with leukemia (n = 18) H-Mr AP was not detectable. After the treatment of the sera with papain and phosphatidylinositol-specific phospholipase C, which release membrane-associated AP from membrane particles, H-Mr AP was no longer detectable. These results indicate that H-Mr AP in the sera of patients with solid tumors may derive from increasing cell shedding of the tumor cells with elevated levels of membrane fragments in serum, which is a well known phenomenon in liver tumors. H-Mr AP was not more detectable in the serum after successful tumor treatment. These data suggest that H-Mr AP was produced by the tumors and that this parameter may be a serological marker for some solid tumors even in the presence of normal total AP serum activity.
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PMID:High-molecular-mass or macromolecular alkaline phosphatase in sera of children with solid tumors. 815 5

We studied the role of proteases in apoptosis using a cell-free system prepared from a human leukemia cell line. HL60 cells are p53 null and extremely sensitive to a variety of apoptotic stimuli including DNA damage induced by the topoisomerase I inhibitor, camptothecin. We measured DNA fragmentation induced in isolated nuclei by cytosolic extracts using a filter elution assay. Cytosol from camptothecin-treated HL60 cells induced internucleosomal DNA fragmentation in nuclei from untreated cells. This fragmentation was suppressed by serine protease inhibitors. Serine proteases (trypsin, endoproteinase Glu-C, chymotrypsin A, and proteinase K) and papain by themselves induced DNA fragmentation in naive nuclei. This effect was enhanced in the presence of cytosol from untreated cells. Cysteine protease inhibitors (E-64, leupeptin, Ac-YVAD-CHO [ICE inhibitor]) did not affect camptothecin-induced DNA fragmentation. The apopain/Yama inhibitor, Ac-DEVD-CHO, and the proteasome inhibitor, MG-132, were also inactive both in the cell-free system and in whole cells. Interleukin-1 beta converting enzyme (ICE) or human immunodeficiency virus protease failed to induce DNA fragmentation in naive nuclei. Together, these results suggest that DNA damage activates serine protease(s) which in turn activate(s) nuclear endonuclease(s) during apoptosis in HL60 cells.
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PMID:DNA fragmentation induced by protease activation in p53-null human leukemia HL60 cells undergoing apoptosis following treatment with the topoisomerase I inhibitor camptothecin: cell-free system studies. 880 33

Oncostatin M (OSM) is structurally and functionally similar to leukaemia inhibitory factor (LIF), interleukin 6 (IL-6), interleukin 11 (IL-11) and ciliary neurotrophic factor (CNTF). We have previously shown that LIF stimulates proteoglycan release and suppresses proteoglycan synthesis in pig and goat cartilage explants. The aim of this study was to determine whether OSM and related cytokines influence proteoglycan metabolism in pig cartilage explants. Slices of pig articular cartilage were incubated for 6 days in serum free DMEM with or without cytokines. The total proteoglycan content in papain digested cartilage explants and medium was determined by the 1,9 dimethylmethylene blue method. Cytokine activity was assessed by determining the percentage release of total proteoglycan. To evaluate proteoglycan synthesis, cartilage was cultured for 48 h under the same conditions and in the final 6 h the tissue was cultured in sulphate free DMEM containing 35SO4. The radioactivity in the medium and tissue was determined in cetylpyridinium chloride precipitates. Biosynthetic activity was expressed as DPM per mg wet weight of cartilage. Dose dependent stimulation of proteoglycan release and suppression of proteoglycan synthesis were observed with rhOSM. IL-6, IL-11 and CNTF also inhibited proteoglycan synthesis in a dose dependent manner but the degree of inhibition was less than that for OSM and these cytokines had no significant effect on proteoglycan release. New biological effects have been identified for OSM and the related cytokines CNTF and IL-11. All three of these cytokines, like LIF and IL-6, suppress proteoglycan synthesis in pig cartilage explants. This common effect suggests that the gp130 subunit of the receptors for these cytokines may represent a common signalling pathway whereby proteoglycan synthesis is regulated. Whilst OSM and LIF stimulate proteoglycan catabolism; IL-6 IL-11 and OSM do not. Thus these effects are not always coupled and activation of gp130 alone may not be a sufficient signal for proteoglycan catabolism.
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PMID:Oncostatin M (OSM) stimulates resorption and inhibits synthesis of proteoglycan in porcine articular cartilage explants. 881 47


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