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

A randomized study of the effects of methionine-deprived amino acid solution (AO-90) on the metabolism of 5-FU was performed in patients with advanced gastric or colorectal cancers. Continuous intravenous hyperalimentation with either AO-90 or conventional amino acid solution (control group) in combination with 5-FU was performed for 7 days preoperatively under the fasting condition. The administration of AO-90 showed a decreased level of serum methionine and resulted in the subsequent increased tendency in the intratumorous levels of both folic acid and methylene tetrahydrofolate compared to those of the control group. In the AO-90 group, the inhibition rate of thymidilate synthase in the tumor was significantly higher than that of the control group. These results indicate that AO-90 plays an important role in the metabolism of 5-FU and seems to contribute to the increased antitumor effect of 5-FU as a biochemical modulator.
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PMID:[Methionine-deprived amino acid solution-induced biochemical modulation of 5-FU and augmentation of the antitumor activity]. 158 Jun 36

Colorectal primary carcinomas and metastases from 20 Dukes' stage C or D patients were examined for the immunohistochemical localization and contents of various fucosylated N-acetyl-lactosamine oligomers by specific monoclonal antibodies (MAbs). MAbs used were SH1, specific for Lewis X antigen; FH4, specific for dimeric Lewis X antigen; FH6, specific for sialyl-dimeric Lewis X antigen; and KH1, specific for Lewis Y-Lewis X antigen. The distribution of the carbohydrate antigens identified by these MAbs was heterogeneous within the primary tumor as well as within the metastatic lesion. Examinations of serial sections indicated that areas within an individual tumor which were stained with one MAb were not always reactive with the other MAbs, although these four MAbs identify closely related structures. The degree of MAb reactivity with carcinoma sections was classified by percentage positive carcinoma cells, and primary tumors and metastases from the same patients were compared. An equivalent or higher proportion of carcinoma cells in the metastatic lesions were reactive with MAb FH6 than in the primary colon carcinomas, but each correlation was not seen with the other MAbs. Electrophoretic separation of tumor tissue extracts followed by staining with these MAbs revealed that a component having an approximate molecular weight of 1,000,000 is the major site for the binding of MAbs, FH6, FH4, and KH1. The electrophoretic mobility of the antigenic molecule on polyacrylamide gels as shown by direct MAb bindings was slightly different from that of a major sialomucin revealed by wheat germ agglutinin in the same tissues. MAb FH6 binding to a high molecular weight component was eliminated by prior treatment of the glycoprotein with mild acid or sialidase to remove sialic acid. Simultaneously, binding of MAb SH2, specific for dimeric Lex antigen, to this component increased. An extract was prepared from a liver metastasis, and high molecular weight components were isolated by gel filtration and then fractionated by DEAE-cellulose ion exchange chromatography. A fraction eluted from DEAE-cellulose between 0.10-0.25 M sodium chloride contained most of the MAb FH6 reactivity, as shown by antibody affinity chromatography. These results support a hypothesis that high molecular weight glycoproteins produced by colorectal carcinoma tissues are heterogeneous with regard to their carbohydrate chains and their antigenic structures may change during tumor progression.
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PMID:Sialyl-dimeric Lewis-X antigen expressed on mucin-like glycoproteins in colorectal cancer metastases. 197 61

Prompted by recent disclosures concerning the potent antitumor activities of 5-deaza-5,6,7,8-tetrahydrofolic acid and 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (DDATHF), we have prepared 5-deazaisofolic acid (3a) and 5-deaza-5,6,7,8-tetrahydroisofolic acid (4a). Reductive condensation of 2,6-diamino-3,4-dihydro-4- oxopyrido[2,3-d]pyrimidine with di-tert-butyl N-(4-formylbenzoyl)-L-glutamate and subsequent deprotection with trifluoroacetic acid yielded 5-deazaisofolic acid in good yield. Catalytic hydrogenation of this analogue then gave 4a. The 9-CH3 and 9-CHO modifications of 3a and the 9-CH3 derivative of 4a were also synthesized. Each of the new analogues was evaluated with a variety of folate-requiring enzymes as well as MCF-7 cells in culture. Compound 4a had an IC50 of ca. 1 microM against MCF-7 cells and was nearly 100-fold less potent than DDATHF in this regard. The three oxidized isofolate analogues were all poor inhibitors of tumor cell growth.
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PMID:Synthesis and biological evaluation of 5-deazaisofolic acid, 5-deaza-5,6,7,8-tetrahydroisofolic acid, and their N9-substituted analogues. 199 83

The mechanism for 5-fluorouracil (5-FU) and cisplatin (CDDP) synergism was investigated in experimental tumor models in rodents in vivo. The reduced folates such as 5, 10-methylenetetrahydrofolate (CH2FH4) and tetrahydrofolate (FH4) which play a significant role in the metabolism of 5-FU were increased about 2 to 3 fold 5 in P388 and Yoshida sarcoma cells of rodents at 24 hours following intraperitoneal administration of CDDP (5 mg/kg), and tritiated 2'-deoxyuridine incorporation into DNA fraction of the CDDP-treated cells was more strongly inhibited than that of non-treated cells after incubation with 5-FU, which indicated the increased formation of a tight ternary complex between thymidylate synthase, FdUMP derived from 5-FU and elevated CH2FH4. The combination of single intraperitoneal CDDP and 6 day-continuous infusion of 5-FU and/or 7 consecutive oral administration 5-FU derivative, BOF-A2, enhanced synergistically the antitumor activity against solid Yoshida sarcomas in rats as compared to each drug alone. These data suggest that CDDP play an important role as not only an effector but also a modulator in biochemical modulation of 5-FU in cellular methionine metabolism and by resultant elevation of intracellular reduced folates.
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PMID:[Mechanism for synergistic antitumor effect in the combination of 5-fluorouracil with cisplatin in vivo tumor models: from the view of biochemical modulation of 5-fluorouracil]. 200 40

We reported previously that treatment of mice bearing MOPC-315 plasmacytoma with the drugs L-PAM (phenylalanine mustard) or 5-FU (5-fluorouracil), in combination with low doses of THF-gamma 2, was more effective in increasing their survival time than treatment with the drug alone. We show here that in the combined treatment using a single injection of 5-FU followed by multiple (8-15) injections of THF-gamma 2, the megadoses were more effective than the low doses in increasing the survival time of MOPC-315 tumor-bearing mice. On the other hand, in combination with L-PAM, both low and high doses of THF-gamma 2 were equally effective. The need for high doses of THF-gamma 2, when used in combination with 5-FU, could be due to the fact that 5-FU acts as a "non-immunomodulating" drug and has to be used at a high, immunosuppressive dose.
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PMID:Therapeutic effectiveness against MOPC-315 plasmacytoma of low or high doses of the synthetic thymic hormone THF-gamma 2 in combination with an "immunomodulating" or a "non-immunomodulating" drug. 201 63

A K562 human erythroleukemia line (designated K562.4CF) was selected for increased tetrahydrofolate cofactor transport in a growth-limiting concentration (0.4 nM) of (6R,S)-5-formyltetrahydrofolate. K562.4CF cells exhibited elevated methotrexate uptake relative to parental cells, attributable to a 10-fold increased influx Vmax. The rate of methotrexate efflux in K562.4CF cells was somewhat increased (55%) as well. The transport system in K562.4CF cells had similar and high apparent binding affinities for methotrexate and 5-formyltetrahydrofolate and a markedly reduced affinity for folic acid, properties typically associated with the "classical" methotrexate/tetrahydrofolate cofactor transporter in tumor cells. Methotrexate uptake in K562.4CF cells decreased substantially under nonselective conditions; high levels of transport were restored in 0.4 nM 5-formyltetrahydrofolate. Treatment of parental and K562.4CF cells with N-hydroxysuccinimide methotrexate inhibited methotrexate influx. N-Hydroxysuccinimide-[3H]methotrexate (700 nM) radiolabeled a broadly migrating band at Mr 76,000-85,000. Incorporation from N-hydroxysuccinimide-[3H]methotrexate into this band was increased 7-fold in K562.4CF over parental cells and was blocked by unlabeled methotrexate, (6S)-5-formyltetrahydrofolate, or, to a lesser extent, folic acid. Whereas incubation with endoglycosidase F had no effect on the electrophoretic migration of the labeled protein, treatment with endoglycosidase F and glycopeptidase F, or endo-beta-galactosidase, reduced the apparent molecular weight to Mr approximately 52,000 or approximately 58,000, respectively. These results suggest that the high-affinity transporter in K562.4CF cells is an N-linked glycoprotein containing internal beta-galactosidic linkages in, or immediately after, unbranched poly-N-acetyllactosamine sequences. Differences in the level of glycosylation may, in part, account for the disparity in the apparent sizes of the homologous folate transport proteins from human and murine cells.
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PMID:Identification of a highly glycosylated methotrexate membrane carrier in K562 human erythroleukemia cells up-regulated for tetrahydrofolate cofactor and methotrexate transport. 205 82

BALB/c mice cured of large MOPC-315 plasmacytomas by melphalan remain deficient in their spleen T-cell functions. This was manifested by impairment of the allogeneic and the antibody responses in vitro to SRBC and in decreased numbers of T-cells including their subsets CD4 and CD8. IL-2 production and specific cytotoxicity against MOPC-315 tumor cells were, on the other hand, maintained. Treatment of these cured mice by in-vivo administration of THF-gamma 2, an octapeptide from calf thymus, repaired these deficits. This was evidenced by in vitro tests with spleen cells which manifested an increased allogeneic response and elevated generation of primary antibody response, restoration of T-cell subpopulations to normal and an enhanced IL-2 production above normal levels. The potential use of THF-gamma 2 as supportive therapy in cancer treatment is suggested.
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PMID:A synthetic thymic hormone, THF-gamma 2, repairs immunodeficiency of mice cured of plasmacytoma by melphalan. 214 Oct 6

The effect of a synthetic thymic hormone, THF-gamma 2, on the anti-tumor activity of spleen cells was studied in mice immunized against the RPC-5 tumor. Following two courses of the THF-gamma 2 treatment, the mean RPC-5 specific cytotoxic response of immune spleen cells was significantly increased when compared to normal cells (P less than 0.001) and to untreated immune spleen cells (P less than 0.04). In addition, THF-gamma 2 treatment improved the competence of immune spleen cells in adoptive immunotherapy (AIT) when performed in combination with chemotherapy by melphalan. Recipients of spleen cells from THF-gamma 2 treated mice showed a 35% increase in survival when compared to AIT with immune cells alone. The results suggest that THF-gamma 2 treatment of donors for AIT might be applicable to cancer therapy in humans.
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PMID:THF-gamma 2, a synthetic thymic hormone, increases effectiveness of combined chemotherapy and immunotherapy against RPC-5 murine plasmacytoma. 229 55

5-Deazaacyclotetrahydrofolate is a cytotoxic tetrahydrofolate analogue which inhibits glycinamide ribonucleotide transformylase (Kelley et al., J. Med. Chem., 33: 561-567, 1990). Cultured mouse L-cells and human MCF-7 and MOLT-4 cells concentrated the drug several hundred-fold after 24 h of continuous exposure to a cytotoxic level (100-200 nM) of radiolabeled drug. High performance liquid chromatography analysis revealed that each cell type metabolized greater than or equal to 80% of the internalized drug to polyglutamated forms, which are more potent glycinamide ribonucleotide transformylase inhibitors. In L-cells, 45% of the polyglutamated metabolites were also N-formylated. The pharmacokinetics and distribution of [14C]-deazaacyclotetrahydrofolate were studied in C57BL/6 male mice. Its plasma half-life was 2.15 h. Radiolabel was concentrated to well above plasma level in the kidney, pancreas, and liver. Metabolism was examined in tumor-bearing and in normal mice. Twenty-four h after a single i.p. injection (50 mg/kg), drug equivalents were 0.6 nmol/g (83% polyglutamated) in colon-38 adenocarcinoma carried s.c., 2.4 nmol/g (100% polyglutamated) in ascitic P388 cells, and 3.7 nmol/g (76% polyglutamated and approximately 20% formylated) in mouse liver. Elimination was mostly in the urine as unmetabolized drug. Feces contained 5-deazaacyclotetrahydropteroate (parent compound less glutamate). In conclusion, 5-deazaacyclotetrahydrofolate was shown to be concentrated to well above the extracellular level and metabolized to more active polyglutamated forms by transformed cells grown in culture and in mice.
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PMID:In vivo and in vitro metabolism of 5-deazaacyclotetrahydrofolate, an acyclic tetrahydrofolate analogue. 233 16

The clinical formulation of leucovorin calcium (leucovorin, LV) is a mixture of stereoisomers [(6R,S)-5-formyltetrahydrofolate], which have been shown to differ significantly in plasma clearance and route of elimination after intravenous administration; the (6S) isomer is rapidly converted to 5-CH3 tetrahydrofolate (5-CH3 THF), and the (6R) isomer is slowly eliminated by renal excretion. The relative importance of (6S) LV and 5-CH3 THF in expanding reduced folate pools in tumor cells is unknown, but it is known that high concentrations of (6R) LV can support growth of folate-depleted cells and thus have the potential to interfere with the biological activity of the (6S) isomer. To examine the pharmacokinetics of the LV isomers and metabolites, we administered 1,000 mg of LV to five normal subjects as a 2-hour intravenous infusion and in divided oral 100-mg doses given over 24 hours. Plasma and urine samples were analyzed by reverse phase followed by chiral high-performance liquid chromatography. Following intravenous administration, peak plasma concentrations of (6R) LV, (6S) LV, and 5-CH3 THF were 148 +/- 32, 59.1 +/- 22, and 17.8 +/- 17 microM, respectively. During oral administration of LV, virtually no (6S) LV appeared in the plasma. Steady-state plasma concentrations of (6R) LV and 5-CH3 THF were approximately 1.5 +/- 0.23 and 2.8 +/- 0.41 microM, respectively. Intravenous administration of LV resulted in an area under the curve (AUC) for (6R) LV that was more than four times that of the biologically active (6S) folates, whereas oral administration produced an AUC for (6S) reduced folates [(6S) LV and 5-CH3 THF] that was approximately twice that of (6R) LV. After administration of high doses of LV intravenously, conversion of (6S) LV to 5-CH3 THF was saturable, as indicated by the prolonged (6S) LV half-life of 58 minutes and the slow (6S) LV clearance of 119.2 +/- 38 mL/min, compared with previously reported data for administration of low doses. This study illustrates that intravenous administration of LV produces equivalent AUCs of (6S) LV and 5-CH3 THF but a substantially higher AUC for (6R) LV. Oral administration over 24 hours results in an AUC of 5-CH3 THF equivalent to that obtained after intravenous dosing in the presence of only small amounts of (6R) LV. The optimal route of LV administration will ultimately be determined by ongoing studies of the cellular pharmacology of LV that will determine if high concentrations of (6R) LV interfere with the biological activity of the (6S) reduced folates.
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PMID:Clinical pharmacokinetics of high-dose leucovorin calcium after intravenous and oral administration. 238 92


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