Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.5.1.3 (dihydrofolate reductase)
5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1-Acyl- and 1,2-diacyl-1,2,4-triazolidine-3,5-diones were found to be potent cytotoxic agents in murine and human cancer cell lines, e.g. L1210, P388, Tmolt3, colon adenocarcinoma, Hela cells and glioma. In vivo activity was demonstrated at 8 mg/kg/day against Ehrlich ascites carcinoma growth. In L1210 cells, 1-acetyl-4-phenyl-1,2,4-triazolidine-3,5-dione, 41, reduced DNA synthesis significantly with moderate reduction in RNA synthesis. Enzyme sites in L1210 cells which were markedly affected were m- and r-RNA polymerase, PRPP amidotransferase, IMP dehydrogenase, dihydrofolate reductase, thymidine, TMP and TDP kinases. Kinetic studies suggest the inhibition of rate limiting enzymes in the purine pathway by 41 was responsible for its cytotoxicity. Acute toxicity studies in mice indicated 41 was safe for therapeutic use at 20, 50, and 100 mg/ky/day.
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PMID:Antineoplastic activities and cytotoxicity of 1-acyl and 1,2-diacyl-1,2,4-triazolidine-3,5-diones in murine and human tissue culture cells. 144 91

The sugar boronated thymidine nucleoside, 5' -0-[(triphenylphosphine-boryl) carbonyl]-3'-0-acetyl thymidine 1, and the boron-modified nucleoside phosphotriester, 5'-(diethylphosphite- cyanoborane)-3'-acetylthymidine 2, were successfully synthesized. Both compounds demonstrated differential activity when tested against eight cell lines, with significant cytotoxic activity against the growth of human Tmolt3 leukemia, colon adenocarcinoma, HeLa S3 uterine carcinoma, and osteosarcoma cells. In in vivo studies these agents were found to be active against the growth of Ehrlich ascites carcinoma at 8 mg/kg/day I.P. and to be marginally active against the growth of L1210 and Lewis lung cancers in mice. The mode of action of these thymidine derivatives in Tmolt3 cells was the inhibition of DNA and protein synthesis. Compound 2 was highly effective in inhibiting DNA polymerase alpha and m-RNA, r-RNA and t-RNA polymerase activities. Both compounds inhibited ribonucleoside reductase activity. The de novo purine pathway appeared to be the major site of inhibition of the agents, with IMP dehydrogenase, PRPP amido transferase, and dihydrofolate reductase activities being significantly inhibited. In the pyrimidine pathway, carbamyl phosphate synthetase and aspartate transcarbamylase activities were inhibited by 1. As expected, d[NTP] levels were significantly reduced by treatment with the agents. DNA strand scission was evident after incubating Tmolt3 cells for 24 hr with the agents.
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PMID:Antineoplastic activity of boron-containing thymidine nucleosides in Tmolt3 leukemic cells. 150 1

2,3-Dihydrophthalazine-1,4-dione derivatives demonstrated potent cytotoxicity against the growth of murine leukemia cells and human single cell suspension, i.e. Tmolt3 leukemia and HeLa-S3, as well as colon adenocarcinoma and KB nasopharynx. However, only select compounds demonstrated activity against bronchogenic lung, osteosarcoma and glioma growth. 2,3-Dihydrophthalazine-1,4-dione was active in vivo against L1210 leukemia, Lewis lung and Ehrlich ascites carcinoma growth. In L1210 cells the agents inhibited both DNA and RNA synthesis, and a few of the compounds were capable of inhibiting protein synthesis at 3 times their ED50 values. When 2,3-dihydrophthalazine-1,4-dione and N-butyl-2,3-dihydrophthalazine-1,4-dione were examined for their mode of action in the L1210 lymphoid leukemia cells, the sites of inhibition by the agents appear to be the de novo purine pathway at the enzymes IMP dehydrogenase and PRPP amido transferase. IMP dehydrogenase activity was inhibited at least 45% by 45 min at 100 microM concentration of drugs whereas the remaining enzymes that were affected by the drugs were not inhibited as early. Secondary sites were dihydrofolate reductase and thymidylate synthetase. The d(NTP) levels were also reduced specifically dATP and dCTP levels.
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PMID:The anti-neoplastic activity of 2,3-dihydrophthalazine-1,4-dione and N-butyl-2,3-dihydrophthalazine-1,4-dione in human and murine tumor cells. 162 17

5-Deaza-10-propargylfolic acid (4), an analogue of the thymidylate synthase (TS) inhibitor 10-propargyl-5,8-dideazafolic acid (PDDF, 1), was prepared via alkylation of diethyl N-[4-(propargylamino)benzoyl]-L-glutamate (7) by 2-amino-6-(bromomethyl)-4(3H)-pyrido[2,3-d]pyrimidinone (15). Bromomethyl intermediate 15 was prepared from the corresponding hydroxymethyl precursor 14 by treatment with 48% HBr. Hydroxymethyl compound 14 was obtained by deamination of reported 2,4-diaminopyrido[2,3-d]pyrimidine-6-methanol (12a) in refluxing 1 N NaOH. Both 12a and its 5-methyl-substituted analogue 12b were converted to versatile 6-bromomethyl intermediates 13a and 13b from which important antifolates may be readily derived. Alkylation of 7 by 13a,b led to 10-propargyl-5-deazaaminopterin (5) and 5-methyl-10-propargyl-5-deazaaminopterin (6). As an inhibitor of TS from H35F/F cells, 4 gave an IC50 value showing it to be approximately 6-fold less inhibitory than PDDF (90 nM for 4 vs 14 nM for PDDF). In in vitro studies, IC50 (microM) values obtained for 4 vs L1210 and S180 of 1.50 and 2.35, respectively, were similar to those obtained for PDDF (2.61 and 1.97). Against HL60 cells, 4 was about 7-fold more cytotoxic than PDDF (IC50 values 0.72 and 5.29 microM). Inclusion of thymidine did not establish TS as the site of cytotoxic action for either 4 or PDDF in the cell lines used. In in vivo tests against L1210 in mice, 4 failed to show therapeutic effect. The 2,4-diamino compounds 5 and 6 were as potent inhibitors of DHFR from L1210 cells as MTX and 7- and 35-fold, respectively, more inhibitory than MTX toward L1210 cell growth. In mediated influx into L1210 cells, 5 and 6 were transported 2.7- and 8.5-fold, respectively, more readily than MTX. Against the EO771 mammary adenocarcinoma in mice, 6 produced greater antitumor effect than MTX. A dose of 36 mg/kg per day for 5 days caused no toxic deaths while the average tumor volume among 10 mice was reduced to 8-9% of that of the control, and 20% of the test animals were rendered tumor free.
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PMID:Synthesis and antifolate evaluation of the 10-propargyl derivatives of 5-deazafolic acid, 5-deazaaminopterin, and 5-methyl-5-deazaaminopterin. 173 51

Initial and steady-state uptakes of serine and phenylalanine by human fibroblasts and human colon tumour cells were studied applying a double isotope dilution technique to perfused populations of cultivated cells retained on microcarrier beads. This new method permits the differentiation of the unidirectional transport parameters and can also distinguish between membrane-associated processes and independently intracellular events in isolated cells. High initial L-serine uptake values in colon adenocarcinoma cells became negative under steady-state conditions. To determine if the observed negative L-serine uptake was produced by the rapid efflux of intracellular L-[3H]serine, the cells were treated with methotrexate (MTX) (an inhibitor of cytosolic dihydrofolate reductase). The modified curve of L-[3H]serine uptake after MTX treatment suggests that, under these experimental conditions, net serine transport is non concentrative in colon tumour cells and could be modulated by the rate of intracellular serine metabolism; it also suggests that MTX does not directly affect serine transport in perfused human colon adenocarcinoma cells. Initial and steady-state uptakes of phenylalanine were high in both fibroblasts and tumour cells and were unaffected by MTX treatment.
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PMID:Rapid and steady-state amino acid transport in perfused human fibroblasts and colon adenocarcinoma cells: effects of methotrexate. 211 48

The Boon-Leigh procedure, involving condensation of a 6-chloro-5-nitropyrimidine (22) with an alpha-amino ketone (20 or 21) followed by reduction of the nitro group, cyclization, and L-glutamylation, led to the formation of 11-deazahomofolate (29) and its 10-methyl derivative (30). The corresponding (6R,S)-5,6,7,8-tetrahydro (4, 5) and 7,8-dihydro (31, 32) derivatives were prepared by catalytic hydrogenation. (6S)-11-Deazatetrahydrohomofolate was prepared from 29 by enzymatic reduction. Compounds 29 and 30 had little effect (IC50 greater than 2 x 10(-5) M) on Lactobacillus casei glycinamide ribonucleotide (GAR) formyltransferase but (6R,S)-11-deazatetrahydrohomofolate (4) is a potent inhibitor of this enzyme (IC50 = 5 x 10(-8) M). It is at least 100 times more inhibitory than 33, the 6S compound, indicating that the 6R component of the mixture having the unnatural configuration at C6 (34) is responsible for the potent inhibition. Compound 4 is a much weaker inhibitor of murine (L1210) and human (MOLT-4) leukemia cell GAR formyltransferases (IC50 greater than 1 x 10(-5) M). (6R,S)-11-Deaza-10-methyltetrahydrohomofolate (5) (IC50 = 1.1 x 10(-5) is 200 times weaker than 4 against L. casei GAR formyltransferase. However, 11-deaza-10-methyldihydrohomofolate (32) is more inhibitory (IC50 = 5.5 x 10(-7) M) than 5 or 30. None of the compounds showed inhibition of L. casei aminoimidazolecarboxamide ribonucleotide (AICAR) formyltransferase, dihydrofolate reductase, or thymidylate synthase. The dihydro derivatives 31 and 32 are 5% as active as dihydrofolate as substrates for L. casei dihydrofolate reductase. Compound 4 showed moderate inhibition of the growth of L. casei, Streptococcus faecium, MOLT-4 cells, and MCF-7 human breast adenocarcinoma cells.
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PMID:Folate analogues. 31. Synthesis of the reduced derivatives of 11-deazahomofolic acid, 10-methyl-11-deazahomofolic acid, and their evaluation as inhibitors of glycinamide ribonucleotide formyltransferase. 249 18

To test the utility of the polymerase chain reaction in identifying single base mutations in a gene known to give rise to an altered enzyme and drug resistance phenotype, a human colon adenocarcinoma cell line resistant to methotrexate, with a known single base mutation (Srimatkandada et al., J. Biol. Chem. 264:3524, 1989) was examined. Poly A+ RNA was used for cDNA synthesis with reverse transcriptase, deoxynucleoside triphosphates, and 5 microM 3' primer that anneals outside the coding region of the human dihydrofolate reductase. The RNA:DNA hybrid was used as a template for the polymerase chain reaction with the addition of a 5' primer and Thermus aquaticus (Taq)I DNA polymerase. These primers flank the coding region of the human dihydrofolate reductase and define a region of 650 bases. The polymerase chain reaction was carried out for 40 cycles resulting in full length transcripts in microgram amounts clearly visible by ethidium bromide staining on agarose gels. DNA was isolated by standard methods, and double-stranded DNA was sequenced by the chain-termination method using TaqI DNA polymerase. A single point mutation was discovered at position 91 (T----C) resulting in a substitution of serine for phenylalanine at codon 31, as determined previously by classical cDNA cloning and sequencing. Sequence analysis indicated that this base transition resulted in the loss of Eco RI and Xmn I sites and the gain of a HinfI site in the cDNA, which were confirmed by restriction digests.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Detection of a single base mutation in the human dihydrofolate reductase gene from a methotrexate-resistant cell line using the polymerase chain reaction. 264 Jan 57

The biochemical rationale for the potentiation of the effects of 5-FU by MTX is based on an increased PRPP level or MTX polyglutamate produced by MTX. The cytotoxic action of MTX results not only from inhibition of DHFR but also depends upon thymidylate synthetase (TS), a key enzyme in DNA synthesis. We obtained a monoclonal antibody to TS using a hydrophilic peptide consisting of 20 amino acids in the TS amino acid sequence and demonstrated by PAP that TS was detectable in poorly differentiated adenocarcinoma cells but not in well differentiated adenocarcinoma cells. Upon clinical application of sequential doses of MTX and 5-FU, the median survival durations were 318 days and 156 days for scirrhous-type gastric cancer patients and non-scirrhous-type gastric cancer patients respectively. These results suggest that immunohistochemistry with TS antibody is available as an indicator of the effect of this drug regimen.
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PMID:[The role of thymidylate synthetase in sequential dose of MTX and 5-FU in the advanced scirrhous type gastric cancer]. 283 88

A series of six 2,4-diaminoquinazoline analogues of folic acid which bear close structural resemblance to methotrexate, 1a, were synthesized by unequivocal routes. Three of these have not been described previously, while complete structural characterization of the remaining compounds is presented for the first time. Each of the compounds was a potent inhibitor of dihydrofolate reductase (DHFR) from rat liver or L1210 leukemia cells having I50 values in a range similar to that of 1a. However, a wide divergence in inhibitory activity toward the growth of human gastrointestinal adenocarcinoma or L1210 leukemia cells in vitro was observed. Compounds having a normal folate configuration at positions 9 and 10 were more inhibitory than their isomeric reversed-bridge counterparts. The N-formyl modifications were the least active of the compounds studied. Unsubstituted or N-methyl modifications competed effectively with tritiated 1a for uptake into L1210 leukemia cells, while N-formyl modifications did not. Against an L1210 cell line resistant to 1a by virtue of altered transport and overproduction of DHFR, partial but not complete cross-resistance was observed for certain analogues. Of the three compounds selected for in vivo evaluation against L1210 leukemia in mice, two had a similar level of antitumor activity to that of 1a. The compound 5,8-dideazamethopterin, 2b, however, was slightly more active than 1a but at substantially reduced dose levels.
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PMID:Chemistry and antitumor evaluation of selected classical 2,4-diaminoquinazoline analogues of folic acid. 396 85

A series of 2-amino-4-hydroxy-quinazolines was synthesized and evaluated as inhibitors of colon adenocarcinoma and the folate-dependent enzymes, thymidylate synthase and dihydrofolate reductase. Of the quinazolines tested, 5,8-dideazaisopteroylglutamate, (IAHQ), when administered at 85 mg/kg on days 2 and 10 after tumor implantation delayed the growth of colon tumor No. 38, and resulted in 6 of 20 tumor-free animals at 90 days. In contrast, methotrexate had no effect on the growth of colon tumor No. 38 at maximally tolerated doses. IAHQ was also active against human colon adenocarcinoma cells (HCT-8) in tissue culture, requiring a concentration of 5 X 10(-7) M to inhibit cell growth 50% after 72 hours continuous exposure. Since IAHQ was an effective substrate for folylpolyglutamate synthetase, we examined the effects of IAHQ and its possible tri-gamma-glutamyl metabolite, 5,8-dideazaisoPteGLu3, on thymidylate synthase and dihydrofolate reductase. Neither IAHQ nor 5,8-dideazaisoPteGlu3 stimulated significant binding of 5-fluorodeoxyuridylate to thymidylate synthase. This was consistent with the observation that IAHQ antagonized the killing of HCT-8 cells by 5-fluorouracil. 5,8 DideazaisoPteGlu3 bound more tightly to thymidylate synthase than dihydrofolate reductase as indicated by Kis of 0.09 and 0.7 microM when deoxyuridylate and dihydropteroylglutamate, respectively, were the variable substrates. Inhibition studies also revealed that binding of IAHQ and 5,8-dideazaisoPteGlu3 to thymidylate synthase is promoted and not antagonized by deoxyuridylate. The data suggests that the biochemical basis for the antitumor effects of IAHQ is the intracellular conversion of IAHQ to poly-gamma-glutamyl metabolites, which inhibit thymidylate synthase via formation of an inhibitor-deoxyuridylate-enzyme complex.
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PMID:Effects of 5,8-dideazaisopteroylglutamate and its possible tri-gamma-glutamyl metabolite (5,8-dideazaisoPteGlu3) on colon adenocarcinoma, and the folate dependent enzymes thymidylate synthase and dihydrofolate reductase. 668 93


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