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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major non-glycosylated structural proteins of feline leukemia virus have been isolated, and competition immunoassays have been developed for each. These proteins include the 27,000- to 30,000-molecular-weight major internal antigen designated p30, a 15,000-molecular-weight protein (p15), an acidic protein of 12,000 molecular weight (p12), and a highly basic 10,000-molecular-weight protein (p10). Immunologically and biochemically corresponding proteins of feline and murine leukemia viruses have been identified. and, on the basis of analogy to the known sequence of a prototype type C virus of mouse origin, the map order of the gag region of the feline type C viral genome has been tentatively deduced as NH2-p15-p12-p10-COOH. The demonstration of two feline leukemia virus gag gene-coded proteins, p15 and p12, expressed in the form of an uncleaved precursor in a mink cell line nonproductively transformed by feline sarcoma virus provides indirect support for the proposed sequence.
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PMID:Feline leukemia virus: biochemical and immunological characterization of gag gene-coded structural proteins. 19 62

The major structural polypeptides, p30 of reticuloendotheliosis virus (REV) (strain T) and p27 of avian sarcoma virus B77, have been compared with regard to amino acid composition. NH2-terminal amino acid sequence, and immunological crossreactions. The amino acid composition of the two polypeptides is distinct, and a comparison of the first 30 NH2-terminal amino acids of REV p30 with that for the first 25 of B77 p27 yields only three homologous residues. In competition radioimmunoassays the polypeptides show no crossreactivity. A comparison of the amino acid composition and NH2-terminal amino acid sequence of REV p30 with those reported for several mammalian retrovirus p30s shows remarkable similarities. Both REV and mammalian p30s contain a large number of polar residues in their amino acid composition and show approximately 40% homology in the first 30 NH2-terminal amino acids. No crossreactivity could be observed, however, in competition radioimmunoassays between Rauscher murine leukemia virus p30 and that of REV. The observations reported here suggest a close evolutionary relationship between REV and the mammalian retroviruses.
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PMID:Amino-terminal amino acid sequence of the major structural polypeptides of avian retroviruses: sequence homology between reticuloendotheliosis virus p30 and p30s of mammalian retroviruses. 20 72

The gene order of the ml Moloney sarcoma virus (mlMSV) specific pP60gag (P60) was determined by direct chemical analysis of the polyprotein. P60 was cleaved with cyanogen bromide (CNBr) into eight partial and complete fragments ranging in mass from 10,000 daltons to 58,000 daltons. Peptide maps of these fragments were compared to maps of p15, p12, and three CNBr fragments of p30. The polarity of p15 and p12 in a CNBr fragment of P60 was determined by carboxypeptidase A digestion; likewise the CNBr fragments of p30 were ordered by aminopeptidase digestion. The linear arrangement of P60 CNBr fragments gave the gene order of NH2-p15-p12-p30-COOH. The m3 isolate of MSV expresses a P70 gag polyprotein. Peptide maps of 48,000-dalton CNBr fragments of m3 P70 and ml P60 were similar and suggested that both polyproteins were similar through the NH2-terminal two-thirds of p30. However, the presence of peptides unique to the 10,500-dalton COOH-terminal fragment of m1MSV p30 and not present in the p30 of either m3MSV or Moloney leukemia virus suggested that the gag gene deletion in the m1 isolate begins in the p30 reading frame.
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PMID:Chemical determination of the m1 Moloney sarcoma virus pP60gag gene order: evidence for unique peptides in the carboxy terminus of the polyprotein. 21 95

The amino acid composition, the COOH-terminal amino acid, and the NH2-terminal amino acid sequence of the first 55 residues of the major internal structural protein, p24, of bovine leukemia virus (BLV) were determined. The compositional data and the results of end-group analysis revealed that, although BLV p24 is chemically distinct, it more closely resembles the p30 structural proteins than the other gag gene products of mammalian retroviruses. It was found that BLV p24 shares the common NH2-terminal proline and COOH-terminal leucine but lacks the common prolylleucylarginine tripeptide and the larger conserved region found near the NH2 terminus of all mammalian type C viral p30s. Alignment of the amino acid sequence of BLV p24 with the previously determined sequence of feline leukemia virus p27 revealed a statistically significant sequence homology. A more distant relationship was found between BLV p24 and other mammalian p30s. The finding of a definite sequence homology between BLV p24 and mammalian type C virus p30s clearly establishes the origin of these contemporary viral proteins from common progenitor genes.
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PMID:Amino-terminal sequence of bovine leukemia virus major internal protein: homology with mammalian type C virus p30 structural proteins. 22 66

Translation of Rauscher murine leukemia virus (R-MuLV) 35S RNA in an mRNA-dependent cell-free protein-synthesizing system yields polypeptides identical to authentic Pr65gag, the R-MuLV gag precursor, and Pr200gag-pol, the precursor to the R-MuLV reverse transcriptase. In addition to these polypeptides, the cell-free product contains a family of polypeptides of less than 65,000 molecular weight which appear to be generated by premature termination of protein synthesis within the viral gag gene. We compared the tryptic maps of several of these less than 65,000-molecular-weight premature termination polypeptides with that of full-size Pr65gag and found a progressive loss of tryptic peptides which could be assigned to known R-MuLV gag proteins. A 40,000-molecular-weight fragment, P40gag, lacked p10 and part of p30, placing p10 at the C terminus pf Pr65gag and p30 ajacent to it. Fragments of 33,000 (P33gag) and 27,000 to 28,000 (P27/28gag) molecular weight showed a successive loss of additional p30 tryptic peptides, but no loss of either p15 or p12. An 18,000-molecular-weight fragment lost p12 but retained p15. These data suggest an R-MuLV gag gene order of NH2-p15-p12-p30-p10-COOH.
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PMID:Tryptic peptide analyses of polypeptides generated by premature termination of cell-free protein synthesis allow a determination of the Rauscher leukemia virus gag gene order. 73 99

In the first approach by total synthesis to the structure of the antitumor antibiotic septacidin, analogues have been obtained which show similar inhibition of RNA-DNA synthesis in cultured leukemia L1210 cells and similar activity against transplanted leukemia P388 in mice. In these analogues, the natural aminoheptose moiety is replaced by 4-amino-4-deoxy-and 4-amino-4,6-dideoxy-L-glucose, to retain the natural configuration of the pyranose ring. Also retained is the lipophilic fatty acid-amino acid side chain attached to the 4-amino group and glycosylation at the 6-NH2 of adenine. If the fatty acid chain was shortened from C16 to C6, if the fatty chain was shifted to the glycine unit, or if the glycine unit was omitted, activity was completely lost. However, activity was retained if the C16 chain was shortened only to C12 or if the glycine unit was extended to beta-alanine. Both active and inactive analogues were nonbinding to DNA and nonmutagenic to Salmonella strains. The synthetic approach was to start with a suitably protected sugar (L-fucose and L-galactose), construct the adenine moiety at C-1 introduce a 4-amino group, and finally attach the preformed side chain.
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PMID:Antitumor septacidin analogues. 91 94

The effect of morphine and cocaine on the transport of hydrolyzed nitrogen mustard (NH2-OH) and choline by peripheral blood cells of normal subjects and patients with chronic lymphocytic leukemia, acute lymphoblastic leukemia, and acute myeloblastic leukemia was determined. Transport of HN2-OH by lymphocytes from normal individuals and patients with chronic lymphocytic leukemia was stimulated by morphine and cocaine and, in each case, the effect was statistically significant (P less than 0.05 or greater). However, choline transport by normal lymphocytes was not altered by cocaine and was only slightly stimulated by morphine; choline transport by lymphocytes from patients with chronic lymphocytic leukemia was not stimulated by either morphine or cocaine. HN2-OH and choline transport by cells from patients with either acute lymphoblastic or myeloblastic leukemia was stimulated to a comparable degree by both drugs. Stimulation of HN2-OH transport by morphine and cocaine was greater in normal lymphocytes than in acute leukemic cells and the differences were highly significant (p less than 0.001). Conversely, stimulation of choline transport was more marked in acute leukemic cells than in normal lymphocytes, and these differences were also highly significant (p less than 0.001). It was previously shown that transport of nitrogen mustard by normal and leukemic human cells was biphasic in nature, consisting of a choline-independent component at "high" drug concentrations and a choline-dependent system at "low" substrate concentrations. The preferential stimulation of the low-dose, choline-dependent system by morphine and cocaine in acute leukemic cells relative to that observed in normal lymphocytes suggests a possible mechanism of increasing the therapeutic index of nitrogen mustard.
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PMID:Drug-induced stimulation of transport of hydrolyzed nitrogen mustard and choline by normal and leukemic human cells in vitro. 106 33

Four quinazoline analogs of isofolic acid were synthesized including 5-methyl-5,8-deazaisofolic acid (8a), 5,8-deazaisofolic acid (8c), as well as their 4-NH2 counterparts 8b and 8d. None of these showed significant activity against L1210 leukemia in mice at dose levels where amethopterin provided significant prolongation in survival.
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PMID:Synthesis of quinazoline analogs of isofolic acid. 115 82

It has become apparent that a number of genes disrupted by chromosomal rearrangements during leukaemogenesis encode protein factors involved in transcriptional regulation (20-25) and PML may be another such gene. The replacement of the NH2-terminal transactivation domain in RAR alpha by the PML putative DNA binding and transactivation domains in the PML/RARA fusion produces a novel chimeric protein which may act to block normal myeloid differentiation through disregulation of the genes normally regulated by either or both of the normal proteins.
Leukemia 1992
PMID:A previously uncharacterized gene, PML, is fused to the retinoic acid receptor alpha gene in acute promyelocytic leukaemia. 131 62

The biological activity of a series of dinuclear bis(platinum) complexes of formula [(cis-PtX2-(NH3)]2(NH2(CH2)nNH2)] (X = Cl, n = 4-9, compounds 6-11; X2 = malonate, n = 5 or 6, compounds 12 and 13) is described in selected murine leukemia, murine solid tumor, and human tumor cell lines and in murine leukemia cell lines rendered resistant to cisplatin (cis-[Pt(NH3)2Cl2]). The bis(platinum) compounds showed greater activity in vitro against murine tumor cell lines resistant to either cisplatin or DACH ([Pt(DACH)Cl2]). The resistance factor is dependent on chain length of the diamine, and the structural feature of a dinuclear complex is of general use in reducing cross-resistance with cisplatin. In vivo [(cis-PtCl2(NH3)]2(NH2(CH2)5NH2)] (7) showed a % T/C of 204 against murine L1210 leukemia resistant to cisplatin compared to a % T/C of 104 for cisplatin itself at optimal doses. The complex [(Pt(mal)(NH3)]2(NH2(CH2)6NH2)] (13) was highly active in the colon 26 tumor line with 3/10 tumor-free survivors (dose of 186 mg/kg, ip D1,5,9); however, 13 was subject to substantial cross-resistance in the cisplatin resistant L1210 leukemia (% T/C 139 versus % T/C of 223 in the sensitive line). In four selected human tumor lines in vitro, compounds 6-11 were uniformly more potent than cisplatin. In the corresponding xenografts, compound 7 showed greater activity in the HCT-8 (coloadenocarcinoma) and H23 (nonsmall cell lung), but diminished potency in AH125 and H520 (both nonsmall cell lung) lines in comparison to cisplatin. Retention of activity against cisplatin-resistant cell lines and a different spectrum of activity compared to cisplatin in some human tumor cell lines suggest that this class of complexes is mechanistically different from mononuclear complexes and worthy of further development toward clinical trials.
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PMID:Anticancer activity in murine and human tumor cell lines of bis(platinum) complexes incorporating straight-chain aliphatic diamine linker groups. 133 74


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