Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of several methylputrescines on the activity of insulin-induced ornithine decarboxylase (ODC) was examined in H-35 hepatoma cells. The induction involved both protein and m-RNA synthesis. Actinomycin D inhibited ODC activity when given up to 1 h after insulin treatment. When added to the medium 2 h or 3 h after the insulin, the activity was increased 100% and 80% respectively. Insulin-induced ODC from H-35 cells had a biphasic half-life, a shorter one of 46 min and a longer one of 90 min. 1-Methylputrescine and 2-methylputrescine were found to be competitive inhibitors of the ODC from H-35 cells with Ki values of 2.8 and 0.1 mM respectively. Putrescine itself was found to have a Ki = 2.4 mM. N-Methylputrescine was a very poor inhibitor of the cell free ODC while 1,4-dimethylputrescine did not show any inhibitory effect. When cellular ODC activity was measured, the four methylputrescines assayed as well as putrescine entirely abolished its activity in the H-35 cells when given at a 1 mM concentration together with insulin. 1-Methylputrescine and 1,4-dimethylputrescine abolished 60% of the activity at a 0.1 microM concentration. All the methylputrescines given at 0.1 mM concentrations decreased the putrescine content of the stimulated cells to the levels found in quiescent cells, but only 1-methyl and 2-methylputrescines decreased spermidine and spermine content. 1,4-Dimethyl and 1-methylputrescines showed a strong inhibition of ODC synthesis, while the other diamines were less inhibitory. At concentrations that abolished ODC activity, 1,4-dimethylputrescine decreased 70% of the total immunoreactive ODC bands, while 1-methyl and 2-methylputrescine decreased them by 50%, and N-methylputrescine and putrescine decreased them by 20%. The lack of decrease in immuno-reactive ODC with the latter two compounds was mainly due to the appearance of immunoreactive degradation products of ODC of low molecular weight. Putrescine and N-methylputrescine affected protein synthesis to a small extent in stimulated cells, while 1-methylputrescine decreased it to the level of non-stimulated cells. Insulin (1 microM concentration) stimulated DNA synthesis in the cells, and this stimulation was doubled in the presence of 2-methylputrescine or putrescine. It can be concluded that, among the methylputrescines assayed, 2-methylputrescine was the best inhibitor of cell-free ODC activity, while 1,4-dimethylputrescine and 1-methylputrescine were the best inhibitors of cellular ODC activity.
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PMID:Modulation of insulin induced ornithine decarboxylase by putrescine and methylputrescines in H-35 hepatoma cells. 205 98

Antitumor effect of TNF has been demonstrated to be increased with some kinds of anticancer agents. We reported antitumor effect of hepatic endogenous TNF induced with gamma-IFN and OK-432 for hepatocellular carcinoma (HCC). To increase antitumor effect of transcatheter arterial embolization (TAE), hepatic arterial chemoembolization was performed with a mixture of gamma-IFN, OK-432 and gelatin sponge following a mixture of Doxorubicin and iodized oil (LPO) on the first time. Serum alpha-fetoprotein decreased from 18,903 ng/ml to 470 ng/ml but elevated three months after these procedures. Following the above procedure, hepatic arterial embolization with a mixture of gelatin sponge and Actinomycin D as an inhibitor of RNA was given the second time. Serum alpha-fetoprotein decreased under 5 ng/ml and computed tomography revealed decreased tumor size and low density area following this second procedure. Hepatic arterial chemoembolization with a mixture of hepatic induction of endogenous TNF and anticancer agents may well be beneficial for survival of patient with HCC.
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PMID:[Chemoembolization combined with hepatic arterial induction of endogenous TNF and anticancer agents for hepatocellular carcinoma--a case report]. 216 47

The effects of lycobetaine (LBT) on DNA single strand break and chromatin conformation were examined by in-situ nick translation method. It was found that LBT did not cause DNA single strand break. After 2-h incubation of murine hepatoma cells with 1-50 micrograms/ml LBT in vitro, the chromatin transcription activity was inhibited gradually. This effect was time- and dose-dependent. Actinomycin D produced a similar effect; 10-hydroxycamptothecin not only caused DNA single strand break, but also altered chromatin conformation; homoharringtonine had no marked influence on either. By molecular hybridization technique, it was found that the effect of LBT on individual genes was somewhat different. After 2-h incubation of the cells with LBT, the sensitivities of c-myc, N-ras, and beta 2-microglobulin genes to DNase I were decreased from 75 +/- 6, 66 +/- 4, 70 +/- 8% to 28 +/- 8, 25 +/- 5, 28 +/- 7%, respectively, while that of c-myb and beta-globin genes (8 + 6%, 6 + 5%) did not change obviously.
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PMID:Effects of lycobetaine on chromatin structure and activity of murine hepatoma cells. 228 45

Kinetics of tyrosine aminotransferase (TAT) mRNA synthesis in Morris rat hepatoma cell lines 7777 and 8994 after dexamethasone treatment (10(-7) M) was studied by molecular hybridization of the RNA with cloned fragments of TAT gene from rat liver cells. It was demonstrated that initiation of TAT gene transcription increased 20 minutes after glucocorticoid treatment. The level of TAT mRNA was not induced by dexamethasone in rat hepatoma cell line 8994. Actinomycin D prevented the deinduction of TAT by stabilization of TAT mRNA.
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PMID:[Regulation of the transcription of the tyrosine aminotransferase gene by glucocorticoids in Morris hepatoma 7777 and 8994 cells]. 289 90

Both phenolic and nonphenolic ring deiodinase activities in monkey hepatocarcinoma cells (NCLP-6E) were increased by addition of serum in a concentration-dependent manner: the stimulatory effect of serum was evident at a concentration as low as 1.5%, and was maximal at 5%. Lineweaver-Burk analysis showed that the increases in the deiodinase activities are due to the increase in Vmax, but not in Km. The addition of cycloheximide at concentrations ranging from 0.1 to 50 micrograms/ml inhibited the stimulatory effect of serum on phenolic ring deiodinase activity progressively. On the other hand, nonphenolic ring deiodinase activity was increased as much as 4-fold by the addition of 0.5-5 micrograms/ml cycloheximide together with 0.5% serum; a high concentration of the drug, 50 micrograms/ml, however, did not elicit such an increase. Actinomycin D at 5 micrograms/ml completely abolished the increase in nonphenolic ring deiodinase activity by serum or cycloheximide. In addition, actinomycin D inhibited the increase in phenolic ring deiodinase activity by serum in a dose-dependent manner at concentrations ranging from 0.05 to 5 micrograms/ml. It is concluded that phenolic and nonphenolic ring deiodinases are regulated by different mechanisms in monkey hepatocarcinoma cells (NCLP-6E).
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PMID:Effects of cycloheximide on inverse regulation of phenolic and nonphenolic ring deiodinases in monkey hepatocarcinoma cells. 391 92

We have found that rat hepatoma cells (R-Y121B) retain alkaline phosphatase activity, and that this enzyme activity is increased by cycloheximide. Actinomycin D also increased the enzyme activity. This increase due to actinomycin D was partially inhibited by cycloheximide. The characteristics of alkaline phosphatase of the cells treated or untreated with cycloheximide or actinomycin D were similar to each other; they were heat labile and the enzyme reaction was strongly inhibited by L-homoarginine, but weakly by L-phenylalanine. The increase in alkaline phosphatase activity with cycloheximide has been termed a 'superactivation' of alkaline phosphatase.
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PMID:'Superactivation' of alkaline phosphatase activity by cycloheximide in rat hepatoma cell cultures. 614 96

Some regularities of [3H]triamcinolone acetonide (TA)binding to glucocorticoid-sensitive Morris hepatoma cell nuclei were studied. It was shown that part of the hormone incorporated into the nuclei form highly stable complexes with nuclear structures that are not destroyed during nuclei lysis with 0.25% SDS. Such complex formation is not practically suppressed by a 500-fold excess of non-labeled TA. As the time of incubation of Morris hepatoma cells with the hormone rises from 10 min to 24 hours, the specific binding of TA to the nuclei decreases, while the specific radioactivity of the [3H]TA-nuclei complexes resistant to 0.25% SDS increases. The stable complexes are eluted from Sepharose 6B together with the bulk of the nuclear proteins and do not contain DNA. Actinomycin D extrudes, to some extent, the [3H]TA from the complexes having specific binding sites that are localized in the nuclei and induces the accumulation of the steroid in the firmly bound nuclear complexes resistant to 0.25% SDS. The ability to suppress hormonal induction of tyrosine aminotransferase was detected only in the antibiotics with a high affinity for the GC-pairs of DNA. i.e., actinomycin D and mitramycin. It was assumed that high concentrations of TA specifically bound to the nuclei are necessary only at initial steps of hormonal induction. At later stages, gradual dissociation of the complexes takes place and the hormone is accumulation within the composition of the SDS-resistant firmly bound complexes.
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PMID:[Interaction of triamcinolone acetonide with Morris hepatoma cells in the presence antibiotics--inhibitors of RNA synthesis]. 615 1

Previous work correlating 51chromium release with aggregate formation between neutrophils and target cells had indicated that unlike killing by lymphocytes, neutrophil-mediated antibody-dependent cellular cytotoxicity (NADCC) in the guinea-pig against hepatoma cells required that three or more neutrophils were simultaneously attached to the target cells. There was virtually no lysis when only one or two neutrophils were attached. This raised the possibility that the target cells could repair lesions inflicted by one or two cells and this was investigated using inhibitors of macromolecular synthesis. Actinomycin D, cycloheximide, puromycin and adriamycin had no effect--militating against a repair mechanism. Surprisingly, mitomycin C led to an exacerbation of NADCC. Chlorambucil, which like mitomycin C is an alkylating agent, had a similar effect though less marked. One explanation of this phenomenon which seemed likely was that the drugs were affecting the cell cycle of the target cells, i.e. that being alkylating agents they might be holding the target cells in a susceptible phase of the cycle. Experiments in which the target cells alone were preincubated with mitomycin C for varying periods of time (2-18 h) before the start of the assay, did not confirm this. However a thirty minute preincubation with mitomycin C of either the neutrophils or neutrophils plus the target cells resulted in increased cytolysis. The results indicate that the effect of mitomycin C in exacerbating NADCC is primarily on the neutrophil.
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PMID:The effect of inhibitors of macromolecular synthesis on neutrophil-mediated antibody-dependent cellular cytotoxicity: exacerbation by mitomycin C. 643 41

The present study was designed to clarify molecular mechanisms underlying inhibitory effect of dexamethasone on leukocyte infiltration in the inflammatory site. For the assay of leukocyte infiltration, two or four blebs were made s.c. on the back of rats by injecting with 2% carboxymethyl cellulose solution containing a chemoattractant, casein. Leukocyte accumulation in the bleb was inhibited considerably by local application of dexamethasone at a concentration of 0.6 X 10(-6) M. Hydrocortisone mesylate, which was reported in the study with hepatoma tissue culture cells to be a long-acting antagonist against glucocorticoid in binding to the corticoid receptor, blocked the above leukocyte inhibitory effect of dexamethasone when applied simultaneously with dexamethasone. The leukocyte infiltration was unaffected by the application of hydrocortisone mesylate alone. Treatment with androstenedione, which was reported to be inactive in the hepatoma tissue culture cells, did not interfere with the inhibitory effect of dexamethasone at all. Actinomycin D, when applied simultaneously with dexamethasone, significantly suppressed the leukocyte-inhibitory effect of dexamethasone. In contrast with those observations, the inhibitory effect of dexamethasone was not affected at all in cases that actinomycin D and hydrocortisone mesylate, respectively, were applied after the administration of dexamethasone. These results indicate essential roles of glucocorticoid receptor and gene expression for the manifestation of the inhibitory effect of dexamethasone on leukocyte infiltration in the inflammatory site.
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PMID:Mechanisms of anti-inflammatory action of dexamethasone: blockade by hydrocortisone mesylate and actinomycin D of the inhibitory effect of dexamethasone on leukocyte infiltration in inflammatory sites. 670 40

1. Direct or indirect inhibitors of l-ornithine decarboxylase (EC 4.1.1.17), structurally related or unrelated to l-ornithine, including dl-alpha-difluoromethylornithine, alpha-methylornithine and 1,3-diaminopropane, used alone or in combination, decreased polyamine concentrations in rat hepatoma tissue culture (HTC) cells and increased S-adenosyl-l-methionine decarboxylase activity (EC 4.1.1.50). 2. Comparison of the catalytic properties of S-adenosyl-l-methionine from cells with elevated and normal activities revealed no apparent modification of the catalytic site as judged by affinity for the substrate, stimulation by di- and tri-amines and inhibition by methylglyoxal bis-(guanylhydrazone). 3. Actinomycin D and cycloheximide, and RNA and a proteinsynthesis inhibitor respectively, blocked the increase of S-adenosyl-l-methionine decarboxylase activity elicited by alpha-difluoromethylornithine. In polyamine-depleted cells the apparent half-life of elevated S-adenosyl-l-methionine decarboxylase activity, determined by inhibition of protein synthesis, was 2.5-fold longer than in control cells. The present results suggest that elevation of S-adenosyl-l-methionine decarboxylase activity by alpha-difluoromethylornithine is due to stabilization of the enzyme. 4. Restoration of the normal intracellular putrescine content, by addition of putrescine to the medium of polyamine-deficient cells, transiently increased S-adenosyl-l-methionine decarboxylase activity. Thereafter, intracellular conversion of putrescine into spermidine was accompanied by inactivation of the enzyme at a rate that was similar to that found on addition of spermidine itself. No relationship between total intracellular spermine content and S-adenosyl-l-methionine decarboxylase activity could be established. 5. Addition of 1mm-1,3-diaminopropane to polyamine-deficient cells did not cause a decrease in the activity of S-adenosyl-l-methionine decarboxylase, whereas addition of 1,5-diaminopentane (cadaverine) did. 1,3-Diamino-N-(3-aminopropyl)propane did not accumulate in cells treated with alpha-difluoromethylornithine and 1,3-diaminopropane, whereas addition of 1,5-diaminopentane led to the accumulation of 1,5-diamino-N-(3-aminopropyl)pentane. 1,3-Diamino-N-(3-aminopropyl)propane (10mum) was as effective as spermidine in decreasing S-adenosyl-l-methionine decarboxylase activity. Thus effectiveness of a diamine in decreasing enzyme activity is related to its capability of being converted into a closely structurally related homologue of spermidine by spermidine synthase. 6. The spermidine site of action appears to be post-translational since (a) the spermidine-induced decrease of S-adenosyl-l-methionine activity was not prevented by actinomycin D and (b) spermidine in the presence of cycloheximide led to a synergistic inactivation of the enzyme with a decay rate that progressively approached control values. Altogether these results are indirect evidence for a strict negative control of S-adenosyl-l-methionine decarboxylase by spermidine and substantiate previous findings [Mamont, Duchesne, Grove & Tardif (1978) Exp. Cell Res.115, 387-393]. Spermidine appears to act on some processes involved in denaturation and/or degradation of the enzyme protein. Putrescine appears to decrease the rate of these processes. The physiological significance of the regulatory control of S-adenosyl-l-methionine decarboxylase is discussed.
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PMID:Indirect evidence for a strict negative control of S-adenosyl-L-methionine decarboxylase by spermidine in rat hepatoma cells. 679 4


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