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)

Methotrexate analogues, in which an additional nitrogen atom is inserted between the phenyl ring and the carbonyl group of the side chain, were prepared by photochemical methods. The compounds were less inhibitory toward dihydrofolate reductase and thymidylate synthetase derived from Lactobacillus casei than was methotrexate. They were also less cytotoxic against human lymphoblastic leukemia cells (CCRF-CEM). In vivo against L-1210 leukemia in mice, the aza homologue of methotrexate showed significant antitumor activity (%ILS = 55%) compared to methotrexate (%ILS = 88%).
 ...
PMID:Methotrexate analogues. 12. Synthesis and biological properties of some aza homologues. 10 16

Folic acid analogues containing an additional nitrogen atom between the phenyl ring and the carbonyl group of the side chain were synthesized. None of the compounds showed significant inhibitory activity against human lymphoblastic leukemia cells (CCRF-CEM) in culture or against Lactobacillus casei (ATCC 7469) growth. Against L1210 leukemia in mice, the aza homologue of folic acid, 4, and the aspartic acid analogue, 14, showed no increase in life span over control animals. These compounds were more toxic in vivo than the corresponding methotrexate analogues. Compound 4 supported the growth of Streptococcus faecium (ATCC 8043), and its tetrahydro derivative supported the growth of Pediococcus cerevisiae (ATCC 8081). These results strongly suggest that 4 can substitute for folate derivatives as cofactors for serine transhydroxymethylase, thymidylate synthetase, and dihydrofolate reductase.
 ...
PMID:Synthesis of aza homologues of folic acid. 10 17

Methotrexate (MTX) inhibition of the growth of mouse or human leukemia cells in culture was partially prevented by either thymidine (dThd) or hypoxanthine. 5-Fluoro-2'-deoxyuridine (FdUrd) also decreased the growth-inhibitory potency of MTX in the presence of small concentrations of 5-formyltetrahydrofolate (citrovorum factor) and sufficient exogenous dThd to support the synthesis of thymidylate nucleotides by salvage mechanisms. In addition, citrovorum factor-induced reversal of MTX was several orders of magnitude more efficient in the presence of both FdUrd and dThd than in the presence of dThd alone or in the absence of both nucleosides. Likewise, the presence of FdUrd (3 microM) and dThd (5.6 microM) completely prevented the lethality of 0.3 mM MTX to L1210 cells in culture medium supplemented with micromolar concentrations of citrovorum factor. We propose that this protection against the cytotoxic effects of MTX by dThd, hypoxanthine, and FdUrd have a common biochemical mechanism--namely, inhibition of the de novo synthesis of thymidylate by either a direct [FdUrd; inhibition of thymidylate synthetase (thymidylate synthase; 5,10-methylenetetrahydrofolate:dUMP C-methyl-transferase, EC 2.1.1.45)] or indirect (dThd and hypoxanthine; feedback inhibition by anabolites on ribonucleotide reductase and deoxycytidylate deaminase) effect. The resultant decreased rate of loss of reduced folates due to de novo thymidylate synthesis would allow a higher degree of inhibition of dihydrofolate reductase to be endured without damage to the cell.
 ...
PMID:Role of thymidylate synthetase activity in development of methotrexate cytotoxicity. 16 May 58

Several 2,4-diaminopyrimidines which inhibit the enzyme dihydrofolate reductase are quantitated following extraction and separation on silica gel thin-layer chromatographic plates. These compounds are candidates for the treatment of brain tumors and meningeal leukemia, because they have the ability to cross the blood-brain barrier. The ultraviolet absorption of the pyrimidine ring at 275 nm is utilized to quantitate these compounds on thin-layer chromatographic plates with a scanning instrument. This method offers the advantages of speed, specificity, versatility and sensitivity, and has proven to be satisfactory for the measurement of as little as 10 ng/ml of these compounds in biological fluids.
 ...
PMID:Quantitative thin-layer chromatography of pyrimethamine and related diaminopyrimidines in body fluids and tissues. 16 16

The dihydrofolate reductase activity has been studied cytochemically in various haematological diseases. The variation between normal controls, Hodgkin's disease, myeloma, polycythaemia vera, chronic lymphocytic leukaemia and chronic myeloid leukamia was not significant, comparing the same type of cells. In acute myeloid leukaemia and acute lymphoblastic leukaemia the blast cells were weakly positive or negative. This finding is very interesting as the blast cells are capable of division. Probably the dihydrofolate reductase appears in the blast cells in some stage of mitosis. Lymphocytes stimulated by phytohaemagglutinin showed increased enzyme activity compared with normal non-stimulated lymphocytes. The "blast like" cells were more strongly positive than the blast cells of leukaemic patients. The patients with acute lymphoblastic leukaemia or acute myeloid leukaemia treated with methotrexate showed increased dihydrofolate reductase activity cytochemically.
 ...
PMID:Cytochemical demonstration of dihydrofolate reductase in leukaemia and other haematological diseases. 26 23

In vitro studies were made on four synthetic polymeric derivatives of the antitumor agent methotrexate (MTX): 1) divinylether-maleic anhydride-MTX (DIVEMA-MTX), 2) poly-L-lysine-MTX (PL-MTX), 3) polyethyleneimine-MTX (PEI-MTX), and 4) carboxymethyl cellulose-MTX (CMC-MTX). They were tested for their ability to inhibit tetrahydrofolate dehydrogenase (dihydrofolate reductase). Their growth inhibition of murine L5178Y leukemia cells was also studied. 1wo of these polymers, DIVEMA-MTX and PEI-MTX, had similar or only slightly reduced activity compared to equivalent concentrations of MTX, whereas PL-MTX and CMC-MTX had significantly higher (1--3 logs) minimal inhibitory concentrations.
 ...
PMID:In vitro inhibitory effects of polymer-linked methotrexate derivatives on tetrahydrofolate dehydrogenase and murine L5178Y cells. 28 2

The interrelated enzymic reactions of folate metabolism are presented and key tetrahydrofolate-producing reactions are emphasized. As observed with the methotrexate (MTX)-resistant mutant strain Streptococcus faecium var. durans/Ak, the regulatory roles of serine and purines in controlling their own synthesis by the repression of enzymes required for co-factor synthesis are reviewed. Positive induction of the dihydrofolate reductase activity of this mutant by folate and the antagonism of the folate effect by purines and thymine are discussed. A protective agent of the reductase-active protein, MTX is viewed also as a "positive" inducer of dihydrofolate reductase. Preliminary studies with L1210 leukemia-bearing mice and the murine leukemia ERLD in vitro suggest that citrovorum factor (CF) also triggers a positive induction of the reductase of the small intestine and of ERLD cells without apparently influencing the reductase level of L1210 in vivo. The possibility that control mechanisms, by which MTX and CF indirectly regulate enzyme synthesis in drug-stressed, CF-rescued cells, contribute to the success of high-dose MTX-CF rescue therapy is introduced.
 ...
PMID:Regulatory control of tetrahydrofolate coenzymes in folate auxotrophs. 30 76

A series of 8-alkyl-7,8,-dihydromethotrexate analogues was prepared by direct alkylation of 7,8-dihydromethotrexate, after pilot studies were performed with simpler pteridines. These compounds are tested for in vitro inhibitory activity against Lactobacillus casei and as enzyme inhibitors against dihydrofolate reductase and thymidylate synthetase derived from this organism. All of the analogues were less inhibitory toward dihydrofolate reductase than was methotrexate but were more inhibitory toward thymidylate synthetase. The analogues were also evaluated for in vitro inhibitory activity against the CCRF-CEM human lymphoblastic leukemia cells. In vivo against the L-1210 leukemia in mice, several of the analogues exhibited some antileukemic activity.
 ...
PMID:Methotrexate analogues. 9. Synthesis and biological properties of some 8-alkyl-7,8-dihydro analogues. 40 42

Analogues of methotrexate (MTX) were prepared by alkylation of side-chain precursors with 6-(bromomethyl)-2,4-pteridinediamine followed, where necessary, by saponification of the intermediate esters and, in two cases, by electrophilic substitution reactions in the pyridine ring portion of 3-deazamethotrexate. Effects of the various modifications on their ability to inhibit dihydrofolate reductase, cytotoxicity, and activity against L1210 leukemia in mice were examined in light of recent findings concerning active transport of MTX and related compounds and the binding features of the MTX-dihydrofolate reductase complex.
 ...
PMID:Analogues of methotrexate. 44 85

Several Mannich bases derived from conjugated styryl ketones were shown to have potent cytotoxicity toward murine leukemia L-1210 cells and Walker 256 carcinosarcoma cells in culture. The most cytotoxic derivative, (E)-1-(3,4-dichlorophenyl)-4-dimethylaminomethyl-1-nonen-3-one hydrochloride, profoundly inhibited the incorporation of tritiated leucine into protein(s) and tritiated deoxythymidine into DNA at concentrations of 0.79-1.32 muM in L-1210 cells. At higher concentrations, incorporation of triated uridine into RNA and tritiated deoxyuridine into DNA was inhibited to a lesser degree. This compound failed to inhibit the enzymes thymidylate synthetase or dihydrofolate reductase up to a concentration of 10-4 M and was ineffective in retarding the growth of the Walker 256 carcinosarcoma in rats.
 ...
PMID:Evaluation of 1-(3,4-dichlorophenyl)-4-dimethylaminomethyl-1-nonen-3-one hydrochloride effect on nucleic acid and protein syntheses using murine leukemia L-1210 cells. 51 84


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