allopurinol and Carcinoma--Hepatocellular

Topics: Adult; Aged; Allopurinol; Autoantibodies; Carcinoma, Hepatocellular; Diagnosis, Differential; Disease Progression; Female; Hepatitis, Autoimmune; Humans; Immunoglobulin A; Immunosuppressive Agents; Incidence; Liver; Liver Neoplasms; Male; Middle Aged; Prognosis; Risk Factors; Survival Rate

Combination treatment with low-dose thiopurine and allopurinol (AP) has successfully been used in patients with inflammatory bowel disease with a so called skewed thiopurine metabolite profile. In red blood cells in vivo, it reduces the concentration of methylated metabolites and increases the concentration of the phosphorylated ones, which is associated with improved therapeutic efficacy. This study aimed to investigate the largely unknown mechanism of AP on thiopurine metabolism in cells with an active thiopurine metabolic pathway using HepG2 and HEK293 cells. Cells were treated with 6-mercaptopurine (6MP) and AP or its metabolite oxypurinol. The expression of genes known to be associated with thiopurine metabolism, and the concentration of thiopurine metabolites were analyzed. Gene expression levels were only affected by AP in the presence of 6MP. The addition of AP to 6MP affected the expression of in total 19 genes in the two cell lines. In both cell lines the expression of the transporter SLC29A2 was reduced by the combined treatment. Six regulated genes in HepG2 cells and 8 regulated genes in HEK293 cells were connected to networks with 18 and 35 genes, respectively, present at known susceptibility loci for inflammatory bowel disease, when analyzed using a protein-protein interaction database. The genes identified as regulated as well as the disease associated interacting genes represent new candidates for further investigation in the context of combination therapy with thiopurines and AP. However, no differences in absolute metabolite concentrations were observed between 6MP+AP or 6MP+oxypurinol vs. 6MP alone in either of the two cell lines. In conclusion; the effect of AP on gene expression levels requires the presence of 6MP, at least in vitro. Previously described AP-effects on metabolite concentrations observed in red blood cells in vivo could not be reproduced in our cell lines in vitro. AP's effects in relation to thiopurine metabolism are complex. The network-identified susceptibility genes represented biological processes mainly associated with purine nucleotide biosynthetic processes, lymphocyte proliferation, NF-KB activation, JAK-STAT signaling, and apoptotic signaling at oxidative stress.

Topics: Allopurinol; Antimetabolites; Carcinoma, Hepatocellular; Drug Therapy, Combination; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Regulatory Networks; HEK293 Cells; Humans; Liver Neoplasms; Mercaptopurine; Methyltransferases; Purines

A series of pyrazolo[3,4-d]pyrimidine derivatives related to allopurinol has been synthesized and evaluated for its cytotoxicity against a panel of three cancer cell lines as well as its xanthine oxidase (XOD) inhibitory activities. Among them, compound 4 showed potent cytotoxicity with IC50 values of 25.5 and 35.2 μM against human hepatoma carcinoma cell lines, BEL-7402 and SMMC-7221, respectively. The anticancer activity of 4 was comparable to that of Tanespimycin (17-N-allylamino-17-demethoxy geldanamycin, 17-AAG) that inhibited the growth of BEL-7402 and SMMC-7221 cells at IC50 values of 12.4 and 9.85 μM, respectively. However, unlike allopurinol, which is also a strong inhibitor of XOD, compound 4 is a much weaker XOD inhibitor, suggesting that the anticancer activities of the allopurinol derivatives may not be associated with XOD inhibition. Moreover, the cytotoxicity of 4 toward normal cells is significantly lower than that of 17-AAG, making 4 a promising lead compound for further optimization of structure-activity relationships that may lead to anticancer agents of clinical utility.

Topics: Allopurinol; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Line, Tumor; Dose-Response Relationship, Drug; Enzyme Inhibitors; Humans; Liver Neoplasms; Molecular Structure; Structure-Activity Relationship; Xanthine Oxidase

The Warburg effect has been found in a wide spectrum of human cancers, however the underlying mechanisms are still unclear. This study aims to explore the role of cellular oxidative stress in relation to glycolysis and the Warburg effect in hepatoma cells.. Various cell lines combining environmental hypoxia was used as an in vitro model to mimic tumor microenvironment in vivo. Superoxide dismutases (SOD) and xanthine oxidase (XO) gene transfection were used to produce various cellular redox levels. 2',7'-dichlorofluorescin (DCF) fluorescence and ESR spectrum were used to detect cellular reactive oxygen species (ROS).. We found that endogenous or exogenous interference with the cellular oxidative stress can sensitively regulate glycolysis and the Warburg effect in hepatoma cells. Hepatoma cells displayed a high level of free radicals compared to immortalized normal hepatocyte cells. Increasing the level of ROS stress in hepatoma cells can directly upregulate HIF-1 and activate glycolysis without requirement of a hypoxic condition. This explains the mechanism whereby aerobic glycolysis, i.e. the Warburg effect arises. Either endogenously upregulating SOD or exogenously administration with antioxidant can, through downregulating ROS level, effectively regulate energy pathways in hepatoma cells and can inhibit the growth of tumor cells and xenograft tumors.. This study suggests that the Warburg effect was related to an inherently high level of cellular ROS and HIF-1. Hepatoma cells adaptation to hypoxia for survival and rapid growth exploits oxidative stress ectopically activated glycolysis to compensate the energy supply. This specific mechanism in which tumor cells through cellular oxidative stress activate glycolysis to meet their energy metabolism requirement could be exploited to selectively kill tumor cells.

Topics: Animals; Carcinoma, Hepatocellular; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cell Survival; Data Interpretation, Statistical; Glycolysis; Humans; L-Lactate Dehydrogenase; Mice; Mice, Nude; Neoplasm Transplantation; Oxidative Stress; Reactive Oxygen Species; Superoxide Dismutase; Xanthine Oxidase

A 77-year-old-man was admitted to hospital for treatment of a huge hepatocellular carcinoma by transarterial chemoembolization. After treatment, the patient developed acute tumor lysis syndrome with hyperkalemia, hyperuricemia, hyperphosphatemia, hypocalcemia, metabolic acidosis and acute renal failure, which was successfully treated. In the treatments of solid organ tumors, acute tumor lysis syndrome is an extremely rare complication. To the best of the authors' knowledge, this patient is the third case of such a complication after transarterial chemoembolization for a hepatocellular carcinoma in the English literature.

Topics: Aged; Allopurinol; Antimetabolites; Carcinoma, Hepatocellular; Chemoembolization, Therapeutic; Humans; Length of Stay; Liver Neoplasms; Male; Radiography; Rehydration Solutions; Sodium Bicarbonate; Treatment Outcome; Tumor Lysis Syndrome

University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) solutions are the 2 most commonly used liver preservation solutions. The aim of this study was to compare cardiovascular stability, acid-base status, and potassium concentrations between patients who received grafts preserved in either UW or HTK solution in orthotopic liver transplantation (OLT).. In this retrospective study, 87 patients who underwent living donor OLT were divided into 2 groups: UW (n = 28) and HTK (n = 59). Group HTK was subdivided into group NF-HTK (n = 31; nonflushed before reperfusion) and group F-HTK (n = 28; flushed before reperfusion). We determined mean arterial pressure (MAP) and heart rate every minute for 5 minutes after reperfusion and the maximum change in these values and incidence of postreperfusion syndrome (PRS). Body temperature, cardiovascular and acid-base parameters, as well as potassium concentrations were compared at 5 minutes before and 5 and 30 minutes after reperfusion.. The maximum decreases in MAP within 5 minutes after reperfusion were significantly greater in both the NF-HTK and the F-HTK groups. The rate of PRS was significantly greater in the NF-HTK compared with the UW group. Flushing with HTK solution decreased the rate of PRS; there was no significant difference between the F-HTK and UW groups. All serial changes in body temperature, cardiovascular and acid-base parameters, as well as potassium concentrations were similar among the 3 groups.. The incidence of PRS was greater using HTK compared with UW solution during the reperfusion period. Therefore, careful hemodynamic management is advised when using HTK solution.

Topics: Acid-Base Equilibrium; Adenosine; Adult; Allopurinol; Blood Pressure; Carcinoma, Hepatocellular; Female; Glucose; Glutathione; Hemodynamics; Humans; Insulin; Liver Cirrhosis; Liver Neoplasms; Liver Transplantation; Living Donors; Male; Mannitol; Middle Aged; Organ Preservation Solutions; Portal Vein; Potassium; Potassium Chloride; Procaine; Raffinose; Reperfusion Injury; Retrospective Studies

Differential effects of superoxide and hydroxyl radical on intracellular calcium were investigated in trout hepatoma cells (RTH-149). [Ca2+]i variations were recorded using confocal imaging, fluo-3 loading, and exposure to various mixtures consisting of hypoxanthine/xanthine oxidase (HX/XO), and of sub-stimulatory concentrations of H2O2 and Cu2+ . No [Ca2+]i variation was found with HX/XO, a slight [Ca2+]i rise with a mixture of Cu2+ and HX/XO, a sustained rise with Cu2+ and H2O2, and the highest rise with Cu2+, H2O2 and HX/XO. Fluorimetric assay using dihydrorhodamine 123 revealed a correlation between the oxidizing power of a mixture and its effect on [Ca2+]i. The [Ca2+]i rise induced by Cu2+, H2O2 and HX/XO, was partially reduced in Ca2+ free medium or in the presence of SOD, converted into Ca2+ transient by verapamil, and almost abolished by the PLC inhibitor U73122 or in the presence of the hydroxyl radical quencher TEMPOL. Data indicate that Ca2+ is mobilized by hydroxyl radical but not by superoxide. The mechanism consists of PLC activation causing intracellular Ca2+ release, while Ca2+ entry potentiates Ca2+ release thus leading to sustained [Ca2+]i rise. A role of hydroxyl radicals in the oxidative switching-on of Ca2+ signaling is discussed.

Topics: Animals; Calcium Signaling; Carcinoma, Hepatocellular; Cell Line, Tumor; Estrenes; Fluorescent Dyes; Hydroxyl Radical; Hypoxanthine; Oxidants; Oxidation-Reduction; Pyrrolidinones; Rhodamines; Superoxides; Trout; Verapamil; Xanthine Oxidase

The water extracts of Cornus officinalis Sieb. et Zuce against hepatocellular carcinoma (HCC) was studied for its chemopreventive potential. Three HCC cell lines (HepG2, SK-Hep1 and PLC/PRF/5) and three leukemic cell lines (U937, K562 and Raji) were tested with XTT assay. Extracts of C. officinalis inhibited all these HCC cells and leukemic cells at a concentration of 100 microg/ml (P < 0.05) and was dose-dependent (P < 0.0001). P53 (P< 0.0001) and Ras (P = 0.001) significantly affected its activity against HCC. Extracts of C. officinalis also possessed the anti-oxidant activity through free radicals scavenging activity at a concentration of 50 microg/ml (P < 0.05). In summary, our experiment implied that C. officinalis might be a candidate for chemopreventive agent against HCC through the antioxidant and anti-neoplastic effects.

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cornus; Drugs, Chinese Herbal; Humans; K562 Cells; Lipid Peroxidation; Liver; Liver Neoplasms; U937 Cells; Xanthine Oxidase

Resveratrol, present in grapes and other plants, is a polyphenolic compound with strong antioxidative activity. In our previous studies, we found that reactive oxygen species (ROS) accelerated the invasive capacity of a rat ascites hepatoma cell line of AH109A in culture and that resveratrol and resveratrol-loaded rat sera suppressed the ROS-potentiated invasion of the hepatoma cells. To study mechanisms by which resveratrol and its in vivo metabolite(s) suppress the invasion, we estimated intracellular peroxide level and expression of hepatocyte growth factor (HGF), a known cell motility factor, in AH109A cells. Exogenously added ROS promoted the intracellular peroxide level and the expression of HGF. Resveratrol and resveratrol-loaded rat sera canceled the rise in the peroxide level and HGF expression in ROS-stimulated tumor cells. These results suggest an involvement of the antioxidative property of resveratrol and sera from rats orally given resveratrol in their suppressive effects on ROS-potentiated invasion of AH109A cells.

Topics: Animals; Carcinoma, Hepatocellular; Free Radical Scavengers; Gene Expression; Hepatocyte Growth Factor; Hypoxanthine; Liver Neoplasms; Male; Neoplasm Invasiveness; Rats; Reactive Oxygen Species; Resveratrol; Stilbenes; Tumor Cells, Cultured; Xanthine Oxidase

The aim of this study was to investigate the level and the form of xanthine oxidoreductase (XOR) in severely diseased human livers, to ascertain whether the modifications of the enzyme activity reported in experimental pathology also occur in human liver disease.. Total, dehydrogenase, and oxidase activities of XOR were measured in samples of human liver removed for transplantation or partial hepatectomy. Samples included four groups: 1) histologically normal liver tissue, adjacent to metastases from extrahepatic tumors (controls), 2) liver with virus-related cirrhosis; 3) liver with virus-negative cirrhosis, and 4) hepatocellular carcinoma tissue (HCC).. The level of total XOR was significantly higher in liver with virus-related cirrhosis, but not in virus-negative cirrhosis, than in controls. In virus-positive cirrhosis, the total XOR activity correlated positively with the level of ALT. The percentage of XOR oxidase activity in cirrhotic liver, regardless of virus infection, correlated positively with aspartate amino-transferase, bilirubin concentration, and partial thromboplastin time, and negatively with prothrombin time. The activity of XOR was significantly lower in HCC than in control tissue or in a nonneoplastic area of the same liver.. Consistent with previous reports in experimental pathology, the level of XOR was increased in cirrhotic liver, in association with viral infection. This increment correlated with ALT, suggesting a relationship between XOR activity and the extent of liver injury caused by viral replication. The percentage of oxidase activity seems to be correlated with tissue damage and consequent liver impairment. The low XOR activity observed in HCC is consistent with reported experimental pathology.

Topics: Adult; Aged; Analysis of Variance; Biomarkers; Carcinoma, Hepatocellular; Female; Humans; Liver Cirrhosis; Liver Neoplasms; Male; Middle Aged; Xanthine Dehydrogenase; Xanthine Oxidase

Resveratrol, found in grapes, is a phytoalexin with antioxidative activity. The compound (100 and 200 microM) inhibited the proliferation of hepatoma cells, although this phytoalexin exerted little influence up to 50 microM. Resveratrol, however, suppressed the invasion of the hepatoma cells even at a concentration of 25 microM. Sera from rats orally given resveratrol restrained only the invasion of AH109A cells. Resveratrol and resveratrol-loaded rat serum suppressed reactive oxygen species-potentiated invasive capacity. These results suggest that the anti-invasive activity of resveratrol is independent of the anti-proliferative activity, and that the antioxidative property of resveratrol may be involved in its anti-invasive action.

Topics: Animals; Antineoplastic Agents; Antioxidants; Carcinoma, Hepatocellular; Cell Division; Hypoxanthine; Liver Neoplasms; Neoplasm Invasiveness; Rats; Resveratrol; Stilbenes; Tumor Cells, Cultured; Xanthine Oxidase

Tumour necrosis factor alpha (TNF-alpha) at 20 ng/ml induced apoptosis in human hepatoma cells in vitro. The effect of TNF-alpha-induced apoptosis was exacerbated by the hypoxanthine-xanthine oxidase (HX/XO) system and cycloheximide (CHX), but alleviated by superoxide dismutase (SOD), suggesting that TNF-alpha-induced apoptosis may be due to oxidative stress, and independent of protein synthesis. TNF-alpha elevated free Ca(2+)concentration, triggered lipid peroxidation and decreased the expression of bcl-2 protein. The findings suggest that TNF-alpha-induced apoptosis may be involved in stimulating Ca(2+)-dependent endonuclease activity and increasing membrane lipid peroxidation. Bcl-2 may play a pivotal role in serving as a Ca(2+)regulator or antioxidant, preventing lipid peroxidation in the process.

Topics: Acridine Orange; Apoptosis; Calcium; Carcinoma, Hepatocellular; Cycloheximide; Flow Cytometry; Humans; Hypoxanthine; Lipid Peroxidation; Liver Neoplasms; Oxidative Stress; Protein Synthesis Inhibitors; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha; Xanthine Oxidase

Serum concentration of thiobarbituric acid (TBA) reactants in the hepatic vein were measured before and after transient dearterialization of the liver in five human subjects bearing unresectable hepatocellular carcinoma (HCC). During 1 hour of the occlusion of the hepatic artery, change in TBA reactants level was slight. However, the mean value of TBA reactants in 1 hour after the reflow increased to 1.50 +/- 0.11 nmol/ml (mean +/- S.E.) and was significantly higher (p < 0.05) than those before hepatic dearterialization (1.28 +/- 0.11 nmol/ml) and just before the release of occlusion (1.32 +/- 0.09 nmol/ml). Further, two endogeneous scavenger enzymes, superoxide dismutase (SOD) and catalase (CAT), and one of the major sources of oxygen free radicals, xanthine oxidase (XOD) were measured in human untreated HCC and the corresponding adjacent liver tissue. The results demonstrated an increase in SOD in 81.8% (9/11) of HCC, and a decrease in CAT in 72.7% (8/11) of HCC when compared with the corresponding adjacent liver tissue. The mean value of SOD in HCC was significantly higher (66.8 +/- 6.5 vs 52.8 +/- 3.8 U/mg protein; p < 0.05), and that of CAT was significantly lower (22.6 +/- 2.4 vs 36.0 +/- 6.1 U/mg protein; p < 0.05) than those in liver tissue. All of nine HCC samples had a significantly lower activity of XOD (6.4 +/- 1.9 vs 20.3 +/- 3.4 pmol/minute/mg protein; p < 0.01) than the corresponding liver tissue. There was no obvious relation between the content of SOD and CAT in HCC, or in liver tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Carcinoma, Hepatocellular; Catalase; Female; Free Radicals; Humans; Ischemia; Liver; Liver Circulation; Liver Neoplasms; Male; Middle Aged; Oxygen; Reactive Oxygen Species; Reperfusion; Superoxide Dismutase; Thiobarbiturates; Xanthine Oxidase

Topics: 5'-Nucleotidase; Adenine Phosphoribosyltransferase; Adenosine Deaminase; Carcinoma, Hepatocellular; Cell Line; Culture Media; Cytosol; Guanine Deaminase; Humans; Hypoxanthine; Hypoxanthine Phosphoribosyltransferase; Hypoxanthines; Liver; Liver Neoplasms; Purine-Nucleoside Phosphorylase; Tumor Cells, Cultured; Xanthine; Xanthine Oxidase; Xanthines

Topics: Allopurinol; Carcinoma, Hepatocellular; Culture Media, Conditioned; Humans; Hypoxanthine; Hypoxanthine Phosphoribosyltransferase; Hypoxanthines; Liver Neoplasms; Oxidation-Reduction; Purines; Tumor Cells, Cultured; Xanthine Oxidase; Xanthines

The NO-releasing compounds 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1), sodium nitroprusside (SNP) and S-nitroso-N-acetyl-DL-penicillamine (SNAP) mediated a rapid loss of viability of Fu5 rat hepatoma cells. SIN-1 in addition to NO also released the superoxide anion radical (O2-.). Its cytotoxicity, however, was not affected by superoxide dismutase. In contrast, the H2O2-converting enzyme catalase significantly, but not completely, diminished cell damage, indicating participation of H2O2 in the tumoricidal activity of SIN-1. Glucose oxidase (5 m-units/ml), producing similar amounts of H2O2 to 5 mM SIN-1, had no effect on cell viability. When 5 m-units/ml glucose oxidase was added to incubations with 5 mM SNP, which alone initiated cell injury of about 40%, cell damage was significantly increased up to 95%. Similar results were observed with 1 mM SNAP and 20 m-units/ml xanthine oxidase, which mediated cytotoxicity of about 90% when both compounds were added together, compared with 35% and 55% cell injury, respectively, induced by the single compounds. The results indicate that a co-operative action with H2O2 enhances the tumoricidal activity of NO in Fu5 cells. No evidence for an interplay of NO with O2-. in cytotoxicity, e.g. via the peroxynitrite anion (ONOO-), was found.

Topics: Animals; Carcinoma, Hepatocellular; Catalase; Cell Line; Cell Survival; Glucose Oxidase; Hydrogen Peroxide; Kinetics; Liver Neoplasms; Molsidomine; Nitric Oxide; Nitroprusside; Penicillamine; Rats; S-Nitroso-N-Acetylpenicillamine; Superoxide Dismutase; Superoxides; Tumor Cells, Cultured; Vasodilator Agents; Xanthine Oxidase

Topics: Adenoma, Bile Duct; Adenosine; Adult; Allopurinol; Bile Duct Neoplasms; Carcinoma, Hepatocellular; Colonic Neoplasms; Duodenal Neoplasms; Duodenum; Female; Glutathione; Humans; Insulin; Intestine, Small; Liver Neoplasms; Liver Transplantation; Male; Middle Aged; Organ Preservation; Organ Preservation Solutions; Pancreas Transplantation; Pancreatic Neoplasms; Raffinose; Solutions

Topics: Allopurinol; Biopsy, Needle; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Glycogen Storage Disease; Hemangiosarcoma; Hemochromatosis; Hepatitis, Alcoholic; Hepatitis, Chronic; Humans; Leprosy; Liver; Liver Cirrhosis, Biliary; Liver Diseases; Liver Neoplasms; Peliosis Hepatis

Injection s.c. of purine 3-oxide into Wistar rats resulted in the appearance of sarcomas and fibromas at the interscapular site of administration, carcinomas in the liver, and a high incidence of s.c. fibromas in the hip at a distance from the site of injection. A small number of liver tumors but not tumors at the injection site appeared in rats to which the parent compound, purine, was administered. Oxidation of purine 3-oxide by xanthine oxidase was found to occur in two steps to yield the potent oncogen 3-hydroxyxanthine. A similar process may occur in vivo since a protein preparation from rat s.c. tissue has similar oxidizing activity.

Topics: Animals; Carcinogens; Carcinoma, Hepatocellular; Connective Tissue; Cyclic N-Oxides; Fibroma; Hypoxanthines; Injections, Subcutaneous; Liver Neoplasms; Male; Neoplasms, Experimental; Purines; Rats; Soft Tissue Neoplasms; Xanthine Oxidase

Cells from a rat hepatoma grown in culture were found to activate methyldopa to intermediates which are bound irreversibly to cellular proteins. The binding reaction was not inhibited by superoxide dismutase or allopurinol, but was strongly inhibited by ascorbic acid and glutathione. Methyldopa, paracetamol and furosemide were not mutagenic in the Salmonella/mammalian-microsome mutagenicity test.

Topics: Acetaminophen; Allopurinol; Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Cells, Cultured; Deferoxamine; Dimethylnitrosamine; Edetic Acid; Furosemide; Glutathione; Liver Neoplasms; Maleates; Methyldopa; Neoplasms, Experimental; Protein Binding; Rats; Superoxide Dismutase; Time Factors; Xanthines

Topics: Adenine Phosphoribosyltransferase; Animals; Carcinoma, Hepatocellular; Cell Division; Female; Guanine Deaminase; Hypoxanthine Phosphoribosyltransferase; Liver; Liver Neoplasms; Liver Regeneration; Male; Neoplasms, Experimental; Purine-Nucleoside Phosphorylase; Purines; Rats; Rats, Inbred ACI; Rats, Inbred BUF; Time Factors; Xanthine Oxidase

Topics: Amidophosphoribosyltransferase; Animals; Carcinoma, Hepatocellular; Cell Division; Cell Transformation, Neoplastic; Female; Genes; IMP Dehydrogenase; Inosine Monophosphate; Inosine Nucleotides; Ligases; Liver; Liver Neoplasms; Liver Regeneration; Lyases; Male; Models, Biological; Neoplasms, Experimental; Pregnancy; Purines; Rats; Urate Oxidase; Xanthine Oxidase

The behavior of the rate-limiting enzyme of purine catabolism, xanthine oxidase (EC 1.2.3.2); was examined in normal liver, in 17 hepatomas of different growth rates, and in rapidly growing differentiating and regenerating liver. Xanthine oxidase activity was measured in the supernatant fluid prepared by centrifugation of 5% homogenates at 100,000 X g for 30 min. There was no uricase activity in the supernatant fluid. The affinity of xanthine oxidase to xanthine was similar in normal liver and in slow- and rapidly growing hepatomas (Km=6 to 8 muM), and theoptimum pH was 8.0; at pH 7.4, the activity was 80% of that at the pH optimum. A standard assay was worked out for the liver and hepatoma systems; the enzyme activity was linear during 60-min incubation and proportionate with amounts of protein added over a range of 0.5 to 3.0 mg. Xanthine oxidase specific activity was 9 times higher in small intestine than in liver. Activities in lung, spleen, kidney, heart, testes, and thymus were 67, 59, 21, 19, 8, and 8%, and in skeletal muscle, brain, and bone marrow activities were 5% of that of the liver. In regenerating liver, xanthine oxidase activity was not changed from that of the liver of sham-operated controls up to 96 hr after operation. The activity of the average differentiating liver cell was less than 5% of that of adult liver during the first week after birth. At postnatal ages of 18, 25, 30 and 40 days, the activity rose to 18, 46, 76, and 94%, respectively, of that of the adult liver. In starvation, hepatic xanthine oxidase activity per cell was preferentially depleted as compared to the decline in protein concentration. Upon refeeding, the enzymatic activity was restored more slowly than the protein content. Since xanthine oxidase activity was decreased in all examined hepatomas, including the slowest-growing, well-differentiated neoplasms, the altered activity of this enzyme appears to be.linked with neoplastic transformatiobosyl 1-pyrophosphate amidotransferase (EC 2.4.2.14), was increassed in the hepatomas, the reprogramming of gene expression results in an imbalance that favors the synthetic over the catabolic potential. This enzymatic imbalance should confer selective advantages to the cancer cells.

Topics: Animals; Carcinoma, Hepatocellular; Cell Differentiation; Cell Division; Cell Transformation, Neoplastic; Female; Genes; Intestine, Small; Kinetics; Liver; Liver Neoplasms; Liver Regeneration; Male; Neoplasms, Experimental; Pregnancy; Purines; Rats; Rats, Inbred ACI; Rats, Inbred Strains; Starvation; Xanthine Oxidase

Xanthine oxidase was decreased 2- to 10-fold in all examined rat hepatomas irrespective of the malignancy; growth rate and degrees of histological differentiation of the neoplasms. The affinity to substrate (KM=6-8 muM) and the pH optimum (8.0) of the liver and hepatoma enzymes were the same. The reprogramming of gene expression, as manifested in the decreased activity of this key purine metabolizing enzyme, appears to be specific to neoplastic transformation. Since glutamine PRPP amidotransferase activity was increased but the opposing enzyme, xanthine oxidase, was decreased in all the hepatomas, the reprogramming of gene expression results in an imbalance that favors synthesis against catabolism. This enzymatic imbalance should confer selective advantages to the cancer cells.

Topics: Age Factors; Animals; Carcinoma, Hepatocellular; Liver; Liver Neoplasms; Liver Regeneration; Male; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Rats, Inbred Strains; Xanthine Oxidase

Mitochondria from beef heart, Morris hepatoma 3924A and Ehrlich ascites tumor (Lettré mutant) have been studied with respect to hydrogen peroxidase and superoxide radical formation and the presence of superoxide dismutase activity (EC 1.15.1.1, superoxide:superoxide oxidoreductase). The generation of superoxide radicals and hydrogen peroxide occurs at the level of the membrane, being present also in mitochondrial fragments. Hepatoma and ascites mitochondria have little or no superoxide dismutase activity. Superoxide radicals appear to be precursors of hydrogen peroxide formation, the reaction being catalyzed by superoxide dismutase.

Topics: Animals; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Cattle; Free Radicals; Hydrogen Peroxide; Hydrogen-Ion Concentration; Kinetics; Liver Neoplasms; Mice; Mitochondria; Mitochondria, Muscle; Myocardium; Neoplasms, Experimental; Organ Specificity; Rats; Superoxide Dismutase; Superoxides; Xanthine Oxidase

Topics: Allopurinol; Animals; Carbon Radioisotopes; Carcinoma, Hepatocellular; Cells, Cultured; Clone Cells; Culture Media; Cycloheximide; Glycine; Growth; Hypoxanthines; In Vitro Techniques; Indicators and Reagents; Kinetics; Liver Neoplasms; Male; Pentosyltransferases; Purines; Pyrazoles; Pyrimidines; Rats; Ribonucleotides; Tritium; Xanthine Oxidase

Topics: Age Factors; Animals; Aspartate Carbamoyltransferase; Carcinoma, Hepatocellular; Crosses, Genetic; Deoxyribonucleases; Female; Fructose; Fructose-Bisphosphatase; Glucose-6-Phosphatase; Liver; Liver Neoplasms; Male; Mice; Mice, Inbred C3H; Mice, Inbred Strains; Ribonucleases; Rodent Diseases; Xanthine Oxidase

Sequential studies on levels of glycogen and lactic acid as well as activities of glucose-6-phosphatase, fructose-1, 6-diphosphatase aldolase, aspartic and ornithine transcarbamylase, arginase and xanthine oxidase were carried out in liver and tumour tissue of mice fed with 0.03% thioacetamide in normal stock diet. It was observed that significant decrease in glycogen content and activities of gluconeogenic enzymes was apparent at the age of 4 months, i.e. 2 months after thioacetamide treatment. Alterations in the other parameters studied were observed later, i.e. at the age of 9 months. Maximum changes were observed in the hepatomas, i.e. at the age of 17 months.

Topics: Amides; Animals; Arginase; Carcinoma, Hepatocellular; Fructose-Bisphosphatase; Fructose-Bisphosphate Aldolase; Glucose-6-Phosphatase; Lactates; Liver; Liver Glycogen; Liver Neoplasms; Male; Mice; Neoplasms, Experimental; Ornithine Carbamoyltransferase; Sulfhydryl Compounds; Transferases; Xanthine Oxidase

Activities of glucose-6-phosphatase, fructose 1,6-diphosphatase, ornithine transcarbamylase, arginase and xanthine oxidase were measured in thioacetamide induced primary hepatoma and its tumour cell suspension. It was observed that the percentage decrease in the activities of all the enzymes in tumour cell suspension was far more than that observed in tumour tissue. However, in these studies no qualitative difference was observed between the parenchymal cells and the tumour cells.

Topics: Amides; Animals; Arginase; Carcinoma, Hepatocellular; Fructose-Bisphosphatase; Glucose-6-Phosphatase; In Vitro Techniques; Liver; Liver Neoplasms; Male; Mice; Neoplasms, Experimental; Ornithine Carbamoyltransferase; Sulfhydryl Compounds; Xanthine Oxidase

Topics: Allantoin; Allopurinol; Animals; Body Weight; Carbon Isotopes; Carcinoma, Hepatocellular; Diet; Enzymes; Growth; Hypoxanthines; In Vitro Techniques; Kidney; Liver; Liver Neoplasms; Male; Neoplasms, Experimental; Nucleosides; Rats; Spleen; Xanthine Oxidase; Xanthines