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

In vitro cleavage of Gazdar murine sarcoma virus Pr65gag, which has all of the antigenic determinants of Moloney murine leukaemia virus Pr65gag, i.e. p15, p12, p30 and p10, by the Moloney murine leukaemia virus proteolytic activity yielded a p30 whose partial NH2-terminal sequence was identical to Moloney murine leukaemia virus. Both [3H]leucine-labelled and unlabelled Pr65gag were used to generate the cleaved p30.
 ...
PMID:In vitro cleavage of Pr65gag by the Moloney murine leukaemia virus proteolytic activity yields p30 whose NH2-terminal sequence is identical to virion p30. 257 53

A cDNA encoding the Mac-2 antigen, a surface marker highly expressed by thioglycollate-elicited macrophages, has been cloned by immunoscreening of a lambda gt11-P388D1 expression library. The nucleotide sequence of the cDNA is identical to that of carbohydrate-binding protein 35, a galactose-specific lectin found in fibroblasts and highly homologous to a rat IgE-binding protein from basophilic leukemia cells. The in vitro synthesized Mac-2 protein displayed the expected carbohydrate- and IgE-binding properties. By pulse-chase analysis and subcellular fractionation studies, the Mac-2 protein was found in the cytosol but was also seen to accumulate in the extracellular medium. The latter finding was surprising in view of the fact that the cDNA did not encode a signal peptide or transmembrane domain. An alternatively spliced cDNA with the potential to encode a NH2 terminally extended Mac-2 protein with a stretch of hydrophobic amino acids at its NH2 terminus was also found, but it is not clear whether it is the source of the extracellular Mac-2. Possible functions for the Mac-2 protein based on its lectin- and IgE-binding properties are discussed.
 ...
PMID:The Mac-2 antigen is a galactose-specific lectin that binds IgE. 258 31

Three new 5,8-dideaza analogues of folic acid devoid of an amino group at position 2 have been prepared by using synthetic routes patterned after earlier methodologies. They were 2-desamino-5,8-dideazaisofolic acid, 2b, 2-desamino-10-thia-5,8-dideazafolic acid, 2c, and 2-desamino-10-oxa-5,8-dideazafolic acid, 2d. These compounds were found to be 4-6-fold more cytoxic toward L1210 leukemia cells than their 2-NH2 counterparts and to be poor inhibitors of mammalian thymidylate synthase. However, they were only 1.5-3-fold less inhibitory toward dihydrofolate reductase than the analogous compounds containing a 2-NH2 group. The known thymidylate synthase inhibitors 2-desamino-10-propargyl-5,8-dideazafolic acid and 10-propargyl-5,8-dideazafolic acid were included in this study for purposes of comparison.
 ...
PMID:Comparison of the biological effects of selected 5,8-dideazafolate analogues with their 2-desamino counterparts. 270 31

A series of 32 cationic platinum(II) complexes of the form cis-[PtA2(Am)Cl]+, where A is a monodentate (NH3 or i-PrNH2) or A2 is a bidentate (ethylenediamine or 1,2-diaminocyclohexane) amine and Am is either a heterocyclic amine based on a pyridine, pyrimidine, purine, piperidine, or a saturated amine (RNH2) ligand, was prepared and screened against in vivo murine tumor models. Each compound was tested against Sarcoma 180 ascites (S180a) in mice, with 20 members of the series showing activity (ILS greater than 50%). Antitumor activity also was demonstrated in 4 of 16 compounds tested in the L1210 murine leukemia model (ILS greater than 25%) and in 3 of 3 tested in the P388 murine leukemia model (ILS greater than 30%). The most active and potent analogues of the series were obtained when A was NH3 and Am was N1-pyridine, N1-4-methylpyridine, N1-4-bromopyridine, N1-4-chloropyridine, N3-cytosine, or N7-2'-deoxyguanosine. Complexes containing chelating and saturated amine ligands (A), as well as two trans isomers of active cis analogues (trans-[Pt(NH3)2(Am)Cl]+, where Am = N1-pyridine or N1-4-methylpyridine), were inactive in the S180a screen. All complexes were characterized by means of elemental analysis, HPLC, and 195Pt NMR spectroscopy, and the structure of one analogue, cis-[Pt(NH3)2(N3-cytosine)Cl](NO3), was determined by using single-crystal X-ray diffraction methods. While members of this series of compounds demonstrate antitumor activity in vivo, these new agents are not classical analogues of cisplatin (i.e. cis-[PtA2X2] complexes), as they contain three nitrogen donors and only one leaving group. The results of these studies suggest that further work should be conducted to better define the limits of the structure-activity relationships among platinum(II) complexes.
 ...
PMID:Chemical and biological properties of a new series of cis-diammineplatinum(II) antitumor agents containing three nitrogen donors: cis-[Pt(NH3)2(N-donor)Cl]+. 290 24

Two human cell lysosomal membrane glycoproteins of approximately 120 kDa, hLAMP-1 and hLAMP-2, were identified by use of monoclonal antibodies prepared against U937 myelomonocytic leukemia cells or blood mononuclear cells. The two glycoproteins were purified by antibody affinity chromatography and each was found to be a major constituent of human spleen cells, representing approximately 0.05% of the total detergent-extractable protein. Both molecules were highly glycosylated, being synthesized as polypeptides of 40 to 45 kDa and cotranslationally modified by the addition of Asn-linked oligosaccharides. NH2-terminal sequence analysis indicated that each was approximately 50% identical to the corresponding mLAMP-1 or mLAMP-2 of mouse cells. Electron microscopic studies of human blood monocytes, HL-60, and U937 cells demonstrated that the principal location of these glycoproteins was intracellular, in vacuoles and lysosomal structures but not in the peroxidase-positive granules of monocytes. Transport of the proteins between organelles was evidenced by their marked accumulation in the membranes of phagolysosomes. A fraction of each glycoprotein was also detected on the plasma membrane of U937 and HL-60 cells but not on a variety of other tissue culture cells. This cell-surface expression may be differentiation related, since the proteins were not detected in the plasma membrane of normal blood monocytes and their expression on U937 and HL-60 cells was reduced when the cells were treated with differentiating agents. Cell-surface expression of both glycoproteins was markedly increased in blood monocytes but not in U937 cells after exposure to the lysosomotropic reagent methylamine HCl, indicating differences in LAMP-associated membrane flow in these cell types.
 ...
PMID:Purification and characterization of human lysosomal membrane glycoproteins. 291 82

Dipyridamole restores sensitivity to Adriamycin (ADR) in drug-resistant cells. In an effort to elucidate the relationship between activity and chemical structure of dipyridamole, the ability to enhance the growth inhibitory effect of ADR, in multidrug-resistant (MDR) P388 murine leukemia cells, was determined for 43 derivatives and related compounds. Since both substituted pyrimidopyrimidines and pteridines enhanced the growth-inhibitory effect of ADR in drug resistant cells, the core skeleton may not be directly involved and rather serve as a carrier for the substituents connected with this activity. The exact positions of the active substituents on the core skeleton did not seem to be critical for exertion of the activity. Activity was dependent on the presence of 3 tertiary amine groups. However, not all tertiary amines showed the same potency which might be related to the degree of basicity and/or the spatial structure of these groups. The most active derivatives carried piperidine and pyrrolidine groups while derivatives with thiomorpholine, 3-hydroxypiperidine or dimethylamine groups had low activity. Activity was also dependent on the presence of a substituent with partial electronegative charges as found in a diethanolamine group. However, this function could be carried out, with even higher efficiency, by a substituent containing 6 pi electrons.
 ...
PMID:Circumvention of adriamycin resistance by dipyridamole analogues: a structure-activity relationship study. 292 78

We report the complete 8714-nucleotide sequence of the integrated bovine leukemia virus genome and deduce the following genomic organization: 5' LTR-gag-pol-env-pXBL-3' LTR, where LTR represents a long terminal repeat and pXBL represents a region containing unidentified open reading frames. This genomic structure is similar to that of human T-cell leukemia virus. The LTR contains a putative splice donor site in the R region. The gag gene encodes a precursor protein with the form NH2-p15-p24-p12-COOH. The NH2- and COOH-terminal regions of the pol product show stronger homologies with those of avian, rather than murine, type C retrovirus, and its structure is identical to that of avian virus. The env gene encodes a surface glycoprotein (gp51) and a transmembrane protein (gp30). In contrast to the pol product, the gp30 shows stronger sequence homology with a murine, rather than avian homologue, indicating the chimeric nature of the bovine leukemia virus genome. Comparisons of the best conserved pol sequences and overall genomic organizations between several major oncoviruses allow us to propose that bovine leukemia and human T-cell leukemia viruses constitute a group, designated as type "E," of Oncovirinae.
 ...
PMID:Complete nucleotide sequence of the genome of bovine leukemia virus: its evolutionary relationship to other retroviruses. 298 8

Feline leukemia virus contains a protease which apparently has the same specificity as murine leukemia virus protease. It cleaves in vitro the Pr65gag of Gazdar-mouse sarcoma virus into the constituent p15, p12, p30, and p10 proteins. We purified the protease and determined its NH2-terminal amino acid sequence (the first 15 residues). Alignment of this amino acid sequence with the nucleotide sequence (I. Laprevotte, A. Hampe, C. H. Sherr, and F. Galibert, J. Virol. 50:884-894, 1984) reveals that the protease is a viral-coded enzyme and is located at the 5' end of the pol gene. As previously found for murine leukemia virus (Y. Yoshinaka, I. Katoh, T. D. Copeland, and S. Oroszlan, Proc. Natl. Acad. Sci. U.S.A. 82:1618-1622, 1985), feline leukemia virus protease is synthesized through in-frame suppression of the gag amber termination codon by insertion of a glutamine in the fifth position, and the first four amino acids are derived from the gag gene.
 ...
PMID:Translational readthrough of an amber termination codon during synthesis of feline leukemia virus protease. 299 7

Bovine leukemia virus protease was purified to homogeneity and assayed by using murine leukemia virus Pr65gag, a polyprotein precursor of the viral core structural proteins, as the substrate. A chemical analysis of the protease, including an amino acid composition and NH2- and COOH-terminal amino acid sequence analysis, revealed that it has an Mr of 14,000 and is encoded by a segment of the viral RNA located between the gag gene and the putative reverse transcriptase gene. As expected from the nucleotide sequence data (Rice et al., Virology 142:357-377, 1985), the reading frame for the protease is different from both the gag and reverse transcriptase reading frames. The 5' end of the protease open reading frame extends 38 codons upstream from the codon for the NH2-terminal residue of the mature viral protease and overlaps the gag open reading frame by 7 codons. The 3' end of the protease open reading frame extends 26 codons beyond the codon for the COOH-terminal residue of the mature protease and overlaps 8 codons of the reverse transcriptase open reading frame. Several lines of evidence, such as protein mapping of the gag polyprotein precursor, the characteristic structure of the mRNA, and promotion of the synthesis of a gag polyprotein precursor by lysine tRNA in vitro, suggest that the protease could be translated by frameshift suppression of the gag termination codon. In vitro synthesized bovine leukemia virus gag-related polyproteins were cleaved by the protease into fragments which were the same size as the known components of bovine leukemia virus, suggesting that the specificity of cleavage catalyzed in vitro by the purified protease is the same as the specificity of cleavage found in the virus.
 ...
PMID:Bovine leukemia virus protease: purification, chemical analysis, and in vitro processing of gag precursor polyproteins. 300 29

A human erythroleukemia cell line, K-562 T1, was adapted to a protein-free chemically defined medium; that is, the medium does not contain any proteins such as exogenous hormones, growth factors, serum and serum albumin. The K-562 T1 cells which can proliferate in a protein-free medium are one of the model systems suitably supporting the autocrine hypothesis, which claims that cancer cells produce and respond to their own growth factors. The K-562 T1 cells were cultured in a protein-free medium at large scale and the growth factors were purified from the conditioned medium. It was found that K-562 T1 cells produce at least two growth factors; one is LGF-I (leukemia-derived growth factor-I) which can stimulate the proliferation of a wide range of human leukemia cell lines and the other is LGF-II (leukemia-derived growth factor-II), which can contribute to the growth of fibroblasts. LGF-I was purified using QAE-Sephadex, Bio Gel P-60 and Mono S FPLC. The purified protein was found to be homogenous by SDS-polyacrylamide gel electrophoresis and NH2-terminal sequence analysis. The molecular weight of LGF-I was 20,000 by SDS-polyacrylamide gel electrophoresis. The 30 NH2-terminal residues of LGF-I are the same as that of ubiquitin. Ubiquitin is a protein found in eukaryotic cells with molecular weight of 8,600. In the nucleus ubiquitin is conjugated to histone 2A to form the nuclear protein A24 which may play a role in regulation of chromatin structure, and in the cytoplasm is part of an ATP-dependent non-lysosomal proteolytic pathway. However, its physiological significance has not yet been fully resolved. Ubiquitin purified from bovine thymus did not show cell proliferating activity for any cells tested. The results suggest that LGF-I is a new autocrine growth factor with a molecular weight of 20,000 daltons, containing ubiquitin at the NH2-terminal end.
 ...
PMID:N-terminal amino acid sequence of leukemia derived growth factor (LGF) from human erythroleukemia cell culture. 303 91


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>