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)

Adherence of cells to extracellular matrix components modulates cellular responses. Here we compared the array of tyrosine phosphorylated proteins induced by the aggregation of the high affinity receptor for IgE (Fc epsilon RI) in fibronectin-adherent and in nonadherent rat basophilic leukemia (RBL-2H3) cells. Adherence to fibronectin in the absence of Fc epsilon RI aggregation induced tyrosine phosphorylation of 105-115-kDa proteins. This phosphorylation was reversed by EDTA and by a synthetic peptide containing the sequence Arg-Gly-Asp, demonstrating a requirement for fibronectin-integrin interaction. Aggregation of Fc epsilon RI in fibronectin-adherent cells markedly enhanced the tyrosine phosphorylation of the same 105-115-kDa proteins. There were minimal differences in tyrosine phosphorylation of other proteins induced by the aggregation of Fc epsilon RI in nonadherent and in fibronectin-adherent cells. Direct activation of protein kinase C and/or increase in calcium influx induced the phosphorylation of the 105-115-kDa proteins only in fibronectin-adherent cells. The magnitude of the phosphorylation of the 105-115-kDa proteins induced by the aggregation of Fc epsilon RI in fibronectin-adherent cells was substantially greater than the sum of that due to adherence to fibronectin and the aggregation of Fc epsilon RI in nonadherent cells. Therefore, cell adherence and the aggregation of Fc epsilon RI synergistically regulate tyrosine phosphorylation of the 105-115 kDa proteins.
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PMID:Cell adherence to fibronectin and the aggregation of the high affinity immunoglobulin E receptor synergistically regulate tyrosine phosphorylation of 105-115-kDa proteins. 844 98

The 56 amino acid nucleocapsid protein (NCp10) of Moloney Murine Leukemia Virus, contains a CysX2CysX4HisX4Cys zinc finger flanked by basic residues. In vitro NCp10 promotes genomic RNA dimerization, a process most probably linked to genomic RNA packaging, and replication primer tRNA(Pro) annealing to the initiation site of reverse transcription. To characterize the amino-acid sequences involved in the various functions of NCp10, we have synthesized by solid phase method the native protein and a series of derived peptides shortened at the N- or C-terminus with or without the zinc finger domain. In the latter case, the two parts of the protein were linked by a Glycine - Glycine spacer. The in vitro studies of these peptides show that nucleic acid annealing activities of NCp10 do not require a zinc finger but are critically dependent on the presence of specific sequences located on each side of the CCHC domain and containing proline and basic residues. Thus, deletion of 11R or 49PRPQT, of the fully active 29 residue peptide 11RQGGERRRSQLDRDGGKKPRGPRGPRPQT53 leads to a complete loss of NCp10 activity. Therefore it is proposed that in NCp10, the zinc finger directs the spatial recognition of the target RNAs by the basic domains surrounding the zinc finger.
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PMID:Two short basic sequences surrounding the zinc finger of nucleocapsid protein NCp10 of Moloney murine leukemia virus are critical for RNA annealing activity. 845 Nov 85

Precise HLA typing is crucial in the selection of marrow donors for the treatment of patients with hematologic malignancy. This study was undertaken to characterize an unusual variant of HLA-A30, designated HLA-A30JS, identified in a patient with leukemia who was a candidate for unrelated donor marrow transplantation. IEF and cDNA-sequencing analyses revealed that A30JS is a novel variant differing from the IEF-defined subtype A30.1 (encoded by the A*3002 allele) by a single amino acid substitution. An unrelated marrow donor was identified who was matched with the patient for HLA-A3, B7, B18, DR2, and DR3, but mismatched within the A30 antigen family for the two distinct alleles A*3002 versus A30JS. These two alleles encode a single amino acid substitution, Arg versus Gly, at position 56 in the alpha 1 domain. Position 56 is located outside the antigen-binding cleft of the class I molecule, suggesting that this substitution may not be functionally significant. Transplantation from this donor was performed and the patient is surviving free of leukemia for more than 700 days after transplant. The maximum acute GVHD observed was scored as grade II, but immunosuppressive therapy is still required for control of chronic GVHD. This study demonstrates how the molecular characterization of a novel HLA-A allele in a patient could facilitate the selection of an unrelated donor. Lacking this information, it would not have been possible to select a donor for this patient, and thus apparently successful marrow transplant could not have occurred.
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PMID:Selection of an unrelated donor for marrow transplantation facilitated by the molecular characterization of a novel HLA-A allele. 845 35

The transforming gene of Abelson murine leukaemia virus (v-abl) codes for a membrane-associated tyrosine-specific protein kinase (abl TPK). Analysis of the v-abl gene has shown that both the fibroblast-transforming and tyrosine-protein kinase activities reside within a minimal region encoding a protein of 43 kDa (p43v-abl), which represents the most active, isolated form of this enzyme. Since the cellular substrates for p43v-abl are yet to be identified, we synthesized by classical solution methods the octapeptide H-Gly-Asp-Thr-Tyr-Thr-Ala-His-Ala-OH, corresponding to the structural sequence of the main putative autophosphorylation site (Tyr 515) of the abl TPK, as well as some of its analogs modified in positions -2, -1, +1 and +3. The synthetic peptides were tested as substrates for the p43v-abl. The kinetic data obtained indicate that the rates of their phosphorylation vary considerably depending on the sequence of the peptide, as expected. As a rule, no significant increment of the efficiency results from each substitution in the parent sequence. While the replacement of the two charged residues, namely Asp-2 and His-7, with neutral Ala is well tolerated, the substitution with amino acids bearing opposite charges is detrimental. The correlation between secondary structure of our synthetic octapeptides and their substrate recognition by p43v-abl was studied using CD and fluorescence spectroscopy in 5 mM Tris, in 98% TFE/Tris and in 30 mM SDS solutions. The comparison of the spectroscopic data with the kinetic parameters does not confirm a close relationship between the conformational properties of these peptides and their enzymatic role.
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PMID:Synthesis and conformational studies on peptides corresponding to a putative autophosphorylation site of abl TPK. 846 52

PVC-211 murine leukemia virus (MuLV) is a neuropathogenic variant of Friend MuLV (F-MuLV) that causes a rapidly progressive neurodegenerative disease in susceptible rodents. PVC-211 MuLV, but not the parental F-MuLV, can infect rat brain capillary endothelial cells (BCEC) efficiently, and the major determinant for BCEC tropism of PVC-211 MuLV is localized within the XbaI-BamHI fragment of the viral genome containing the 5' half of the env gene. To further dissect the XbaI-BamHI region for its effects on BCEC tropism, we constructed recombinant viruses between PVC-211 MuLV and F-MuLV and tested their infectivity on a cell line established from rat BCEC. Our results indicated that Glu116-to-Gly and Glu129-to-Lys substitutions in the background of the F-MuLV envelope SU protein were sufficient for conferring BCEC tropism on the virus. Interference studies of these viruses on Rat-1 fibroblastic cells showed that the structure of the SU protein encoded by the XbaI-BamHI region also has significant effects on their affinity for the rat ecotropic MuLV receptor. These results support the possibility that structural elements I and II of the SU protein are important determinants for virus-receptor interaction.
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PMID:Effects of subtle changes in the SU protein of ecotropic murine leukemia virus on its brain capillary endothelial cell tropism and interference properties. 856 Jul 61

Monocyte chemoattractant protein-1 (MCP-1) mediates monocyte migration into tissues in inflammatory diseases and atherosclerosis. We have investigated structure-activity relationships for human MCP-1. Mutations were introduced based upon differences between MCP-1 and the structurally related but functionally distinct molecule interleukin-8 (IL-8). Mutant proteins produced using the baculovirus/insect cell expression system were purified and their ability to stimulate monocyte chemotaxis and elevation of intracellular calcium in THP-1 monocytic leukaemia cells was measured. Two regions in MCP-1 were identified as important for its biological activity. One region consists of the sequence Thr-Cys-Cys-Tyr (amino acids 10-13). Point mutations of Thr-10 to Arg and Tyr-13 to Ile greatly lowered MCP-1 activity. The second functionally important region is formed by Ser-34 and Lys-35. Insertion of a Pro between these two residues, or their substitution by the sequence Gly-Pro-His, caused nearly complete loss of MCP-1 activity. Competition binding experiments showed that the mutations that affected activity also lowered the ability to compete with wild-type MCP-1 for receptors on THP-1 cells. Point mutations at positions 8, 15, 30, 37, 38 and 68 had little effect on MCP-1 activity. The important regions that we have identified in MCP-1 correspond with previously identified functionally important regions of IL-8, suggesting that the two molecules bind to their respective receptors by similar contacts.
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PMID:Site-directed mutagenesis of monocyte chemoattractant protein-1 identifies two regions of the polypeptide essential for biological activity. 857 3

Examinations of 174 children and 188 adult patients with acute nonlymphoblastic leukemia (ANLL) demonstrated a similar structure of distribution of ANLL FAB-variants in children and adults, although the incidence of M0 and M4 blasts was somewhat higher in infants aged under 2. In patients under 15 and over 60 peroxidase activity in myeloblasts was reliably lower than in the rest patients. HLA-Dr, Thy-1, CD11a, T-CD19, Gly-A, and Eb antigens were equally incident in the cells of children and adults. The expression of CD11b, CD38, and CD10 antigens on the blasts was higher in children than in adults. An abnormal blast karyotype was detected in 81.8% children and 73.7% adults. Translocation (8;21) was observed in patients with the M2 variant, as a rule (82%), and reliably more frequently in children; t(9;22) and t(11q23) occurred in children somewhat more frequently than in adults. A group of children with primary ANLL (n = 3) was distinguished for the first time, in whose cell karyotype a deletion of chromosome 5 was found. The findings indicate that the biological characteristics of blast cells differ in children and adults. Evidently, the level of hemopoiesis involvement in ANLL is earlier in infants under 2 and subjects over 60 than in the rest patients.
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PMID:[Acute nonlymphoblastic leukemias in children and adults]. 858 69

Prodrugs of mitomycin C (MMC) based on soluble poly-[N-(2-hydroxyethyl)-L-glutamine] (pHEG) polymers have been evaluated as tumour-targeted drugs. These materials are designed to exploit the enhanced permeability of tumour vasculature, combining a passive tumour tropism with decreased systemic liberation of free MMC. A tri- or tetrapeptide linkage (e.g. Gly-Phe-Ala-Leu) between pHEG and the aziridine nitrogen of MMC can combine good hydrolytic stability with rapid cleavage by lysosomal enzymes, releasing free MMC. The conjugates showed decreased systemic toxicity and could be administered to mice at a total MMC dose of 15 mg/kg i.v., compared with just 6 mg/kg for free MMC. Conjugates also showed better activity against animal models of established tumours, achieving up to 77% increased life span (ILS) against solid P388 leukaemia, compared with only 23% for free MMC, and up to 121% ILS against solid C26 colorectal carcinoma, compared with no activity for the free drug. Improving the therapeutic index of anticancer drugs by combining tumour tropism with decreased systemic toxicity is a versatile approach that should produce a new generation of improved anticancer agents.
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PMID:Polymeric prodrugs of mitomycin C designed for tumour tropism and sustained activation. 876 29

Myelopeptide-2 (MP-2) Leu-Val-Val-Tyr-Pro-Trp originally isolated from the supernatant of porcine bone marrow cell culture was examined for its capacity to restore the mitogen responsiveness of human T lymphocytes inhibited by conditioned media from HL-60 leukemia cells (HL-60 CM). MP-2 added to phytohemagglutinin (PHA)-stimulated T lymphocytes together with HL-60 CM abolished the suppression of T-lymphocyte proliferative response in a dose-dependent manner. Another bone marrow hexapeptide Phe-Leu-Gly-Phe-Pro-Thr, MP-1, did not display this action in that experimental system. MP-2 was also effective being added after T-lymphocyte exposure to HL-60 CM which suggests its recovery but not protective effect on T-lymphocytes treated with tumor cell products. Flow cytometry analysis revealed HL-60 CM influence on the expression of CD3 and CD4 T-cell surface antigens. It decreased the content of CD3- and CD4-positive cells and induced the appearance of T lymphocytes with reduced density of CD3 and CD4 antigens. MP-2 was able to restore the T-cell phenotype altered by HL-60 CM. MP-2 seems to be promising in anti-tumor therapy.
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PMID:The bone marrow peptide (myelopeptide-2) abolishes induced by human leukemia HL-60 cell suppression of T lymphocytes. 880 11

The water-soluble conjugates of mitomycin C (MMC) with N-succinyl-chitosan (N-Suc-chitosan) and glycol-chitosan (Gly-chitosan), named N-Suc-chitosan-glu-MMC and Gly-chitosan-glu-MMC, respectively, were characterized mainly by the plasma concentration-time profiles of MMC after intraperitoneal administration and their in vivo antitumor effect against P388 leukemia and Sarcoma 180. Before in vivo evaluation, polymer-drug binding characteristics were checked by gel-chromatography. Gel-chromatographs proposed the covalent binding of 1a-(4-carboxybutyryl)-MMC (glu-MMC) with both the polymer supports. The plasma concentration of MMC showed that each conjugate released MMC in vivo at a similar rate. Kinetic analysis suggested that the in vivo drug release should be considerably faster than the in vitro release in the buffer, pH 7.4, alone. In the treatment against P388 leukemia inoculated intraperitoneally, Gly-chitosan-glu-MMC showed the highest increase in life span (ILS) at 10 mg MMC eq/kg. It was lethally toxic at the dose of 20 mg MMC eq/kg, while N-Suc-chitosan-glu-MMC gave the highest ILS value at this dose. Each conjugate exhibited a little larger ILS value than MMC. For the Sarcoma 180 solid tumor inoculated subcutaneously, the polymer characteristics affected the antitumor effect. Namely, with the intravenous injection, Gly-chitosan-glu-MMC hardly exhibited any tumor growth inhibition, but N-Suc-chitosan-glu-MMC showed significant tumor growth suppression. As to the intratumoral administration, the tendency to suppress tumor growth was observed in MMC and both the conjugates.
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PMID:In vivo drug release and antitumor characteristics of water-soluble conjugates of mitomycin C with glycol-chitosan and N-succinyl-chitosan. 888 36


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