Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The immunological properties of peptidoglycan (L-PG) purified from the cell wall skeleton (L-CWS) of Listeria monocytogenes strain EGD were investigated and compared with the properties of L-CWS. L-PG consisted of alanine, glutamic acid, alpha, epsilon-diaminopimelic acid, muramic acid, and glucosamine. L-PG showed potent adjuvant activities for circulating antibody formation and development of delayed-type hypersensitivity to bacterial alpha-amylase in vivo and for the primary immune response to sheep erythrocytes in vitro, as well as L-CWS. Both L-PG and L-CWS enhanced the generation of cell-mediated cytotoxicity in allogeneic mice and activated thioglycolate-elicited peritoneal macrophages and macrophage cell line RAW 264 to kill tumor target cells in vitro. We also found that L-PG acted on normal spleen cells as a mitogen. Both L-PG and L-CWS had tumor (Meth A)-suppressive and -regressive activities in syngeneic mice. Our results suggest that the L-PG moiety retains the adjuvant and antitumor activities of L-CWS.
 ...
PMID:Adjuvant activity of purified peptidoglycan of Listeria monocytogenes in mice and guinea pigs. 681 94

The present study investigates the fate of effector T cell population against tumor-associated transplantation antigens (TATA) of X5563 plasmacytoma in syngeneic mice rendered specifically unresponsive to the TATA. In this tumor system T cell-mediated tumor-specific immunity was induced by intradermal inoculation of viable tumor cells followed by the surgical resection of the tumor (immunization procedure). The intravenous (iv) presensitization of syngeneic hosts with X-irradiated tumor cells abolished the capability of those hosts to develop the tumor-specific immunity after the above appropriate immunization procedure. Spleen cells from the pretreated mice which subsequently received the immunization procedure could not regain the tumor-neutralizing activity after enzymatic treatment with papain. Moreover, lymphoid cells from the pretreated mice could not be stimulated by the immunization procedure even after proteolytic treatment with papain or trypsin, followed by transfer into other recipient mice free of the serum suppressive factor(s). On the other hand, such enzyme treatment was capable of preventing the tolerance induction of dinitrophenyl (DNP)-primed B cells after in vitro pulsing with DNP-D-GL (copolymer of D-glutamic acid and D-lysine) for 2 hr, suggesting that the enzymatic treatment used here was adequate to remove the blocked receptor and any tolerogen. These results suggest that in X5563 plasmacytoma system, the above specific unresponsiveness induced by the iv presensitization with TATA is due to the irreversible inhibition or deletion of effector T cell clones rather than mere effector cell blockade.
 ...
PMID:The mechanism of specific suppression in effector T cell clones against tumor-associated transplantation antigens. 703 82

A nuclear antigen was purified from the 0.01 M Tris-HCl/pH8 extract of nuclei of the Burkitt tumor Namalwa cell line to electrophoretic homogeneity by DEAE cellulose chromatography, affinity chromatography, and preparative isoelectric focusing. The yield of antigens was 0.02% of the nuclear 0.01 M Tris-HCl/pH8 extract. On two-dimensional gel electrophoresis, the major antigen separated into two adjacent protein spots with molecular weights of 68,000 and an approximate pI of 6.3 (68/6.3 A and 68/6.3 B). A minor antigen had a molecular weight of 61,000 and pI of 6.0 (61/6.0). Fourteen 125I-labeled peptides were obtained from the tryptic digest of the major antigen (68/6.3 A and 68/6.3 B). The amino-acid composition analysis of the purified antigens indicated that the amino acids in the highest content were glycine (15%), glutamic acid (11.6%), and serine (9%); the ratio of acidic to basic amino acids was 1.95. In studies on nucleolytic activity, the purified antigen produced a single-stranded and then a double-stranded cleavage of PM 2 and pBR 322 DNA. This antigen is the first purified nuclear antigen that reacts with the HeLa-specific nucleolar antibodies.
 ...
PMID:Isolation and partial characterization of a nuclear antigen (68/6.3) from the Namalwa cell line (a Burkitt lymphoma). 707 18

Reported antifolate activity against leukemia L1210 by N-[14-[[(2-amino-4-hydroxy-6-quinazolinyl)methyl]-propargylamino]benzoyl]]-L-glu tamic acid through potent inhibition of thymidylate synthase (EC 2.1.1.45) prompted us to include the propargyl group in a study of the effect on folate metabolism and membrane transport of replacing the 10-methyl group of methotrexate with other groups. Along with the propyl (8a) and octyl (8b) homologues of methotrexate, the propargyl compound 8c was prepared for evaluation. Syntheses of 8a,b were achieved by a standard multistep sequence involving preparation of the side-chain precursors via tosylated intermediates and then their alkylation with 6-(bromomethyl)-2,4-pteridinediamine hydrobromide. The side-chain precursor to 8c was prepared by direct alkylation of diethyl N-(4-aminobenzoyl)-L-glutamate with propargyl bromide and was separated from unchanged amine and dipropargyl coproduct by a combination of methods, including dry-column chromatography and recrystallization. Subsequent steps leading to 8c were like those used to prepare 8a,b. Biological evaluations of the three compounds consisted of studies of their effects on enzyme inhibition [(dihydrofolate reductase (EC 1.5.1.3) and thymidylate synthase)], L1210 cell growth inhibition, cellular membrane transport with various murine cell types (L210, S180, Ehrlich, and epithelial), in vivo (mice) activity vs. L1210 leukemia and S180 ascites, and plasma clearance in mice. The in vivo results vs. S180 ascites offered evidence that 8c might have a better therapeutic index against this tumor than methotrexate, but no other result from either of these compounds suggested significant superiority over methotrexate.
 ...
PMID:10-Propargylaminopterin and alkyl homologues of methotrexate as inhibitors of folate metabolism. 710 7

The effects of amino acids on the enhanced agglutinability of bladder cells with concanavalin A induced by subcarcinogenic treatment with N-butyl-N-(4-hydroxybutyl)nitrosamine were examined. The amino acids examined were L-alanine, L-arginine, L-asparagine, L-aspartic acid, L-cysteine, L-glutamic acid, L-glutamine, L-glycine, DL- and L-histidine, L-hydroxyproline, L-isoleucine, D- and L-leucine, L-lysine, L-methionine, DL- and L-phenylalanine, L-proline, L-serine, L-threonine, DL-, D- and L-tryptophan, L-tyrosine and D- and L-valine. They were added to powdered diet at a concentration of 2.0%. L-Leucine, L-isoleucine, L-valine, DL- and D-tryptophan prolonged the period during which the bladder cells showed enhanced agglutinability with concanavalin A. Leupeptin, a protease inhibitor, and L-leucyl-L-leucine were also examined at a concentration of 0.1% because of their similar chemical structures, and were found to have the same effect. The tumor-promoting effects of DL-tryptophan and leupeptin have already been established by in vivo carcinogenesis experiments. The effects of L-leucine, L-isoleucine, L-valine, D-tryptophan and L-leucyl-L-leucine, detected by this short term assay, suggest that these compounds may also be promoters of bladder cancer in rats.
 ...
PMID:Detection of amino acids as possible promoters of bladder cancer in rats by measuring their enhancement of agglutination of bladder cells by concanavalin A. 716 May 80

Tissue polypeptide antigen (TPA) is a complex protein which has been originally identified in extracts of pooled tumors using horse antisera raised against the insolubles of human tumor cells. The antigen is now routinely detected and measured by a previously described hemagglutination inhibition assay. It has been shown by this method that the concentration of the antigen is higher in tumor tissues and in sera of cancer patients as compared to normal tissues or normal sera, respectively. In aqueous solutions, pH 2-12, TPA has a tendency to form high molecular weight aggregates. However they can be dissociated in sodium dodecyl sulfate into subunits, each appearing as a single chain peptide: B1 (Mr 4.3 x 10(4)), B2 (Mr 3.0 x 10(4)), C (Mr 1.7 x 10(4)). The subunits saturate anti-TPA serum indistinguishably from TPA. Amino acid composition of TPA and subunits is dominated by glutamic acid, aspartic acid and leucine, cysteine being absent in subunit B1. The isoelectric point of the main subunit, B1, is 4.4-4.6. Sedimentation and diffusion analyses indicate that pure subunit B1 in aqueous solution exists in distinct oligomeric states.
 ...
PMID:Biochemical properties of tissue polypeptide antigen. 740 46

N-acetylmuramyl-L-alanyl-D-isoglutamine, or muramyl dipeptide (MDP), has been shown to be the minimal structure necessary for adjuvant activity. This compound can replace whole mycobacteria in Freund's complete adjuvant. In our continuing investigation of bacterial cell wall fragments of biological and immunotherapeutic interest, the necessity of obtaining MDP analogs of varying structure has proven to be of primary importance. We have found that the published routes to MDP could be effectively shortened to four steps starting from commercially available starting materials. As an example of this scheme, synthesis of the seryl analog will be detailed. gamma-benzyl glutamic acid could be elaborated in one step to the N-tertiary butoxycarbonyl seryl-gamma-benzyl isoglutamine. Deprotection of the Boc group followed by condensation with 1-O-benzyl-4, 6-O-benzylidine N-acetyl muramic acid provided the protected MDP. Deprotection of this product by hydrogenolysis gave the final product. Physical chemical and biological data as proof of structure is presented. Utility of these compounds in the line-10 tumor system is demonstrated.
 ...
PMID:A shortened synthesis of adjuvant dipeptide (MDP). 741 3

Classical antifolate inhibitors of thymidylate synthase (TS) often require the reduced folate uptake system in order to exert their antitumor effects. In addition, these analogues are polyglutamylated via the enzyme folylpoly-gamma-glutamate synthetase (FPGS), which prevents analogue efflux from the cell and usually increases their inhibitory potency against TS. Impaired function of the reduced folate uptake system and that of FPGS are potential sources of resistance to such antifolates. We designed and synthesized a classical 6-5 ring-fused analogue N-[4-[(2-amino-6-methyl-3,4-dihydro-4-oxo-7H-pyrrolo[2,3- d]pyrimidin-5-yl)thio]-benzoyl]-L-glutamic acid (5) and a nonclassical 6-5 ring-fused analogue 2-amino-6-methyl-5-(pyridin-4-ylthio)-3,4-dihydro-4-oxo-7H-pyrrolo [2,3- d]pyrimidine (6) as TS inhibitors and antitumor agents. The syntheses of analogues 5 and 6 were achieved via the oxidative addition of the sodium salt of ethyl 4-mercaptobenzoate or 4-mercaptopyridine to 2-(pivaloylamino)-6-methyl-3,4-dihydro-4-oxo-7H-pyrrolo[2,3-d]pyri midine (17) in the presence of iodine. For the synthesis of 5 the ester obtained from the reaction was deprotected and coupled with diethyl L-glutamate followed by saponification. Compound 5 was a potent inhibitor of human and bacterial TS with IC50 values of 42 and 21 nM, respectively. Compound 6 was 10-fold less potent than 5 against human TS but more than 4700-fold less potent than 5 against Lactobacillus casei TS. The classical analogue 5 was neither a substrate nor an inhibitor of human FPGS derived from CCRF-CEM cells. Compound 5 was cytotoxic to CCRF-CEM and FaDu tumor cell lines as well as to an FPGS-deficient subline of CCRF-CEM. Thymidine protection studies established that TS was the primary target of 5.
 ...
PMID:5-Arylthio-substituted 2-amino-4-oxo-6-methylpyrrolo[2,3-d]pyrimidine antifolates as thymidylate synthase inhibitors and antitumor agents. 747 77

Peptides that are bound by the murine class I MHC molecule H-2Kk have been isolated and sequenced. The initial step in the fractionation was affinity column isolation of the peptide-class I complex from either RDM-4 or x5563 tumor cell lines. Acid denaturation of the complex followed by HPLC fractionation of the peptides allowed us to sequence individual peptides, as well as pools of peptides. To date, a total of 10 sequences have been characterized, and all were 8 mers. The sequences were variable except for glutamic acid in the second position (P2) and isoleucine in the eighth (P8), which were highly conserved. To further study peptide binding to H-2Kk, a competitive binding assay consisting of the immobilized histocompatibility protein and a biotinylated self-peptide for signal generation was developed. A complete set of single-alanine variants for this one self-peptide was tested in the assay, demonstrating that substitution at P2 and P8 markedly decreased the affinity for the class I molecule; alanine at position 3 had an intermediate effect on binding. A comparison of the identified self-peptides for binding to H-2Kk showed that they differed in affinity by more than one order of magnitude. Influenza virus nucleoprotein peptide, SDY EGR LI, associated with the plate-bound class I molecule, and the resulting MHC-peptide complex could trigger TNF release by influenza-primed CTLs. This result demonstrated the functional activity of the plate-bound H-2Kk-peptide complex.
 ...
PMID:Characterization of peptide binding to the murine MHC class I H-2Kk molecule. Sequencing of the bound peptides and direct binding of synthetic peptides to isolated class I molecules. 752 49

Resistance to anti-cancer drugs has proved to be a major barrier in the clinical management of neoplastic disease. We have investigated the mechanistic basis for resistance to folate-based thymidylate synthase (TS) inhibitors using two cell lines selected for resistance to ZD1694 (N-(5-[N-(3,4-dihydro-2-methyl-4-oxoquinazolin-6-ylmethyl)-N -methylamino]-2 - thenoyl)-L-glutamic acid), a drug currently in phase III clinical trial. The degree of resistance was > 20,000 for the human lymphoblastoid cell line W1L2:R and approximately 14 for the ovarian carcinoma cell line CH1:R. In both cases resistance was associated with increased TS activity. The W1L2:R cell line had an approximately 100-fold increase in TS gene copy number and mRNA levels and a 500- to 1000-fold increase in enzyme levels determined using quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Southern and Western blotting. The CH1:R cell line had an approximately 2- to 2.5-fold increase in TS gene copy number, mRNA and protein levels. In both cell lines the fold resistance determined was significantly higher than the fold increase in target enzyme DNA, mRNA or protein levels. Small changes in TS levels may therefore translate to clinically significant alterations in drug sensitivity.
 ...
PMID:Molecular characterisation of two cell lines selected for resistance to the folate-based thymidylate synthase inhibitor, ZD1694. 753 19


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