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J Bartholeyns

Publications and source records attributed to J Bartholeyns.

At least 37 records · Page 2Linked to original sources
PubMed1988

Control of the antitumoral activity of human macrophages produced in large amounts in view of adoptive transfer.

Purified human blood monocytes were grown in hydrophobic bags in RPMI medium containing additional amino acids, indomethacine and growth factors. Autologous serum was added after a few days of culture at 37 degrees C, 5% CO2. The antitumoral activity generated by activated monocytes against human tumor cells grown in vitro was mediated by soluble effectors in contrast to macrophages which acted by cell contact. Monocyte differentiation into macrophages was achieved after 7 days of culture and characterized by phagocytosis and expression of MAX 1 antigen and non-specific esterases. The macrophages remaining in suspension in the bags were activated by exposure to immunostimulating compounds used alone or in combination (recombinant human gamma-interferon and muramyldipeptide). Activated macrophages were cytotoxic in vitro against U 937 or ovary carcinoma tumor lines (95% cytotoxicity) at a 1/1 effector/tumor cell ratio. The antitumoral potency of activated macrophages was confirmed in vivo where adoptive transfer of one million human macrophages twice a week to nude mice bearing human ovary carcinoma caused a marked regression of the primary tumor.

Animals↗
PubMed1988

Immunotherapy of cancer: experimental approach with activated macrophages proliferating in culture.

Murine macrophages isolated from the peritoneal cavity or from the lung were continuously grown and expanded in vitro on a confluent layer of "mesothelial or endothelial" feeding cells. These cell lines could be obtained from C57B16 or BalbC mice and were nontumorogenic in nude mice. The macrophages were characterized by their capacity to phagocytose yeasts and by the presence of nonspecific esterases, of Fc receptors, and of specific antigens (MAC1 ...). In vitro, these macrophages were fully activated and were tumoricidal against different tumor cell lines. In vivo, adoptive transfer of the expanded macrophages to mice bearing EMT6 sarcoma or 3LL metastasizing carcinoma inhibited the growth of the primary tumors and the development of metastases. Local injection in the vicinity of the primary tumor and i.v. transplantation were effective. The adoptive transfer of expanded macrophages could lead to a new kind of immunotherapy of neoplastic diseases combining selective amplification with effective activation of macrophages as key effector cells.

Animals↗
PubMed1987

Growing tumors induce hypersensitivity to endotoxin and tumor necrosis factor.

Lewis lung carcinoma and EMT6 sarcoma growing as solid tumors in mice caused a gradual increase in the susceptibility of the animals to lethal toxicity of endotoxins (lipopolysaccharides [LPS]). By day 15 following inoculation of the tumors, the 50% lethal dose of LPS, which in normal mice was approximately 400 micrograms, decreased to 2 micrograms for the sarcoma-bearing mice and 0.1 microgram for the carcinoma-bearing mice. This sensitization to endotoxin was paralleled by a high sensitization to tumor necrosis factor (TNF). Human recombinant TNF given to normal mice was lethal at about 500 micrograms. It was lethal for 50% of the animals bearing EMT6 or Lewis lung carcinoma tumors in amounts of 4 and 0.01 micrograms, respectively, on day 15 following tumor inoculation. The sensitization of tumor-bearing animals to LPS and TNF was paralleled by marked granulocytosis.

Animals↗
PubMed1984

Antitumor properties of (2R,5R)-6-heptyne-2,5-diamine, a new potent enzyme-activated irreversible inhibitor of ornithine decarboxylase, in rodents.

(2R,5R)-6-Heptyne-2,5-diamine hydrochloride (MDL 72175) is a new, potent, and selective inhibitor of mammalian ornithine decarboxylase. MDL 72175 given p.o. in drinking fluid reduced by 80% the growth of EMT6 sarcoma in mice and of HTC hepatoma in rats. It prolonged the survival of mice bearing L1210 or P388 leukemias and inhibited the development of Lewis lung carcinoma in mice at doses 10- to 20-fold lower than those of alpha-difluoromethylornithine, the most widely used irreversible inhibitor of ornithine decarboxylase. MDL 72175 depleted putrescine and spermidine levels in the tumors to the same extent as did alpha-difluoromethylornithine. In the EMT6 sarcoma, MDL 72175 achieved at low doses a greater maximal antitumor effect than did alpha-difluoromethylornithine. In combination therapy, MDL 72175 plus Adriamycin gave at least additive antitumor effects on solid tumors and experimental leukemias in animals. The combination MDL 72175 plus methylglyoxal bis(guanylhydrazone) also gave additive antitumor effects on P388 leukemia, associated with an increased uptake of methylglyoxal bis(guanylhydrazone); in contrast, antagonistic effects were observed with this combination on EMT6 tumors in mice. Since MDL 72175 did not present toxicity at effective antitumor doses, this new ornithine decarboxylase inhibitor can be considered as a promising antitumor drug.

Alkynes↗
PubMed1984

Involvement of histamine in growth of mouse and rat tumors: antitumoral properties of monofluoromethylhistidine, an enzyme-activated irreversible inhibitor of histidine decarboxylase.

The present study suggests that newly synthesized histamine is involved in the development of some animal tumors (e.g., Lewis lung carcinoma in mice and Morris hepatoma in rats). A marked induction of histidine decarboxylase (HDC) and an increase in the histamine concentration were observed in the tumors approximately 1 week after inoculation, and there were parallel increases in ornithine decarboxylase activity and the concentrations of polyamines. The H2 receptor antagonist, cimetidine, significantly reduced tumor growth in the animal models while the H1 receptor antagonist, dexchlorpheniramine, had no effect, suggesting that histamine could act via H2 receptor sites. Extensive depletion of tumor histamine induced by local injection of Compound 48/80 did not result in a significant cytostatic effect. Monofluoromethylhistidine (MFMH), an enzyme-activated irreversible inhibitor of HDC, retarded the growth of hepatoma tissue culture cells grown in culture, and when infused s.c. at 60 mg/kg/day it greatly inhibited the development of tumors induced i.m. by hepatoma tissue culture cells in Buffalo rats. MFMH also had pronounced antitumoral effects on EMT6 sarcomas and Lewis lung carcinomas in mice, which were associated with inhibition of HDC and depletion of the histamine content of the tumors. These cytostatic effects were clearly enhanced when MFMH was combined in therapy with the specific ornithine decarboxylase inhibitor, DL-alpha-difluoromethylornithine. The antitumoral effects of the combination were associated with marked decreases in the tumor histamine and putrescine contents. It is proposed that nascent histamine, like newly synthesized putrescine and spermidine, plays a role in the rapid proliferation of animal tumors. Inhibition of HDC by essentially nontoxic drugs such as MFMH could represent a novel approach to the control of neoplastic growth.

Animals↗
PubMed1983

Subcellular distribution of ornithine decarboxylase in rat liver and accessibility of the enzyme to alpha-difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase.

The subcellular localisation of ornithine decarboxylase and of its synthetic irreversible inhibitor, alpha-difluoromethylornithine, was investigated in control rat livers and in livers of animals in which the enzyme was induced by partial hepatectomy or by treatment with dexamethasone. Ornithine decarboxylase activity was distributed in normal rat liver between the nuclear (40%, mainly nucleolar) and the cytosolic (43%) fractions. Cytosolic liver ornithine decarboxylase was markedly induced after partial hepatectomy or treatment with dexamethasone, whereas the enzyme associated with the nuclear fraction was not induced by these procedures. The irreversible inhibitor was found only in the cytosol fraction and was totally absent from the nuclear fraction.

Animals↗
PubMed1983

Treatment of metastatic Lewis lung carcinoma with DL-alpha-difluoromethylornithine.

The effects of DL-alpha-difluoromethylornithine (DFMO), a specific, irreversible inhibitor of ornithine decarboxylase (ODC), on tumors induced in the muscle of C57BL mice by Lewis lung (LL) carcinoma cells and on the development of lung metastases have been investigated. ODC activity and putrescine, spermidine and spermine concentrations were increased both during the early phase of development of the primary LL tumor and in the lung coinciding with the development of metastases. Oral treatment with DFMO (2% aqueous solution as sole drinking fluid, equivalent to 4 g DFMO/kg/day) decreased markedly the ODC activity and the putrescine and spermidine concentrations of the primary tumor, and stimulated S-adenosyl-L-methionine decarboxylase activity. ODC activity and putrescine and spermidine concentrations were similarly markedly reduced in the metastatic lung by DFMO treatment. By comparison with untreated controls, DFMO treatment from day 1 after inoculation resulted in an 81% decrease in tumor size and a 92% reduction of lung metastases by day 20 and prolonged the mean survival time from 20.2 to 28.8 days. The same treatment regimen started 8 days after tumor inoculation resulted in a 52% inhibition of tumor growth and an 82% reduction of lung metastases, and prolonged the mean survival time to 24.9 days. The clear antitumoral effects obtained with DFMO on this animal metastatic cancer indicate its potential value in the treatment of metastases in humans.

Adenosylmethionine Decarboxylase↗
PubMed1982

Effects of cross-linked dimers of ribonuclease A or of lysozyme on the processing of endocytosed peroxidase by hepatoma cells.

Cross-linked dimers of ribonuclease, added at a concentration of 0.05 mg/ml to the culture medium of hepatoma (HTC) cells, were previously shown to inhibit intracellular degradation of peroxidase taken up by endocytosis. Intracellular localization showed that endocytosed peroxidase does not reach lysosomes in dimer-treated cells. The present study shows that preloading of lysosomes with fluorescent anti-peroxidase IgG, obtained by exposing HTC cells for 48 h to 0.1 mg of antibody/ml, restores intracellular degradation of endocytosed peroxidase. Moreover, accumulation of peroxidase into lysosomes, which no longer occurs in dimer-treated cells, occurs again under these conditions. We conclude that inhibition of transfer of peroxidase from phagosomes to lysosomes is most likely to be the alteration resulting from the exposure of the cells to ribonuclease dimer, rather than inhibition of fusion between phagosomes and lysosomes. The dimer of another basic protein, lysozyme added at a concentration of 0.2 mg/ml to the culture medium, is shown to induce the same type of effects as does the dimer of ribonuclease; the half-life of endocytosed peroxidase increased from 5 to 15 h after 2 h exposure of HTC cells to dimerized lysozyme. The effect of both dimers on intracellular protein processing can be reversed by addition of 100 mm-galactose to the culture medium, up to 5 h after pretreatment of the cells. The dimers of ribonuclease A or of lysozyme have thus probably the same mechanism of action. Evidence that the two dimers share the same binding sites on the cells is presented.

Animals↗
PubMed1982

Effect of alpha-monofluoromethyl histidine, an irreversible inhibitor of histidine decarboxylase, on gestation in mice.

Chronic administration of alpha-monofluoromethyl histidine, a specific inhibitor of histidine decarboxylase, to pregnant mice blocked histidine decarboxylase activity and markedly depleted histamine levels in 18-day-old foetuses and in newborn mice. Such treatment had no effect on implantation or embryonic development or parturition suggesting that de novo synthesis of histamine is not a significant factor in these processes in the mouse.

Animals↗
PubMed1981

Effects of alpha-difluoromethylornithine alone and combined with adriamycin or vindesine on L1210 leukemia in mice, EMT6 solid tumors in mice, and solid tumors induced by injection of hepatoma tissue culture cells in rats.

The effects of alpha-difluoromethylornithine (DFMO; RMI 71782) in combination with vindesine or Adriamycin were investigated in three different animal tumor models. When given in a concentration of 2% in drinking water to C57BL/6 X DBA/2 F1 mice inoculated i.p. with L1210 leukemia cells, DFMO prolonged the survival time 1,2-fold. Treatment with vindesine (0.1 mg/kg/week i.p. or Adriamycin (2.5 mg/kg/week i.p.) increased the mean survival time 1.4- and 2.3-fold, respectively. DFMO with vindesine doubled survival time, while DFMO with Adriamycin increased it 3.5-fold and yielded 30% long-term survivors. The growth of solid tumors induced in Buffalo rats by i.m. injection of hepatoma tissue culture cells was inhibited 65% after 2 weeks of DFMO treatment. Similar inhibition of growth could be achieved by weekly i.p. injections of vindesine (0.2 mg/kg) or Adriamycin (2.5 mg/kg). When the same doses of these drugs were administered in combination with DFMO, the growth of this hepatoma was completely arrested. Combined treatment of BALB/c mice bearing s.c. solid EMT6 tumors with DFMO and adriamycin or vindesine also resulted in enhanced inhibition of tumor growth compared to single-drug therapy. These results indicate that combination of DFMO with vindesine or Adriamycin is an effective approach to the treatment of several animal cancers.

Animals↗
PubMed1981

Enhanced urinary excretion of N1-acetylspermidine and the presence of tumors.

We have studied the urinary excretion of free and acetylated polyamines in hepatoma-bearing Buffalo rats during the period of linear growth of the tumor mass. The excretion of nonconjugated polyamines was unchanged. N1-Acetylspermidine excretion did not parallel the linear increase in tumor mass but increased exponentially. Enhancement of N8-acetylspermidine excretion above control levels was observed only at a time when the average tumor mass was 35 +/- 9 (S.D.) g. shortly before the period when necrosis is usually observed. These data taken together with the analysis of urinary acetylpolyamines in rats bearing mammary tumors and in two melanoma patients show that the determination of the N1-acetylspermidine/N8-acetylspermidine ratio in urine may be of only limited value as an indicator for the presence of tumors.

Animals↗
PubMed1979

Characterization of subcellular components in synchronized hepatoma cells as a function of the cell cycle.

The specific activity and subcellular distribution of marker enzymes for the main subcellular components were analysed in homogenates of synchronized hepatoma cells (Morris 7288c), obtained by selective detachment at mitosis combined with a metaphase block with Colcemid. Markers for lysosomes, mitochondrial outer membrane, plasma membrane and cytosol are synthesized throughout the cycle at the same rate as the bulk of cellular protein. Larger variations are observed for a Golgi marker; after a decrease around mitosis, the specific activity of galactosyltransferase increases steadily from middle G(1)-phase on, and at the end of G(2)-phase it is nearly twice that observed at the beginning of G(1)-phase. Our results show that synthesis of cytochrome oxidase may occur preferentially in G(2)-phase. Large modifications of the density distribution of lysosomes are observed during the cell cycle; the median equilibrium density of lysosomal markers decreases in G(1)-phase, and some increase in soluble activity occurs at the same time. Reverse changes occur progressively during S- and G(2)-phases. At mitosis, Golgi galactosyltransferase shows a more dispersed distribution, and modifications in the density distribution of endoplasmic-reticulum NADPH-cytochrome c reductase are observed. The latter can be most easily explained by a detachment of ribosomes from endoplasmic-reticulum membranes. No significant modifications occur in mitochondrial and plasma-membrane markers.

Animals↗
PubMed1979

Inhibition of the discharge of endocytosed protein from phagosomes into lysosomes in hepatoma cells exposed to dimerized ribonuclease A.

The mechanism of the cytostatic action of dimerized ribonuclease A toward cultured hepatoma cells was investigated. A decrease in mitotic index, modifications of adsorptive properties of the pericellular membrane and inhibition of the degradation of two different proteins taken up by endocytosis are the first cell functions to be affected by the dimer. This effect on protein digestion is not due to an inhibition of proteolytic enzymes. The intracellular localization of exogenous protein and of ribonuclease dimer was studied by cell fractionation. When proteins (horseradish peroxidase or rabbit immunoglobulin G) are taken up by control hepatoma cells, they are first associated with phagosomes equilibrating at a lower density than lysosomes; their density distribution gradually becomes similar to that of lysosomes. When cells are pre-exposed to ribonuclease dimer, this modification of the density distribution as a function of time no longer occurs, although these proteins are still intracellular, as indicated by fractionation by differential centrifugation. During the first hour after addition of ribonuclease dimer, kinetic studies show an increased fixation of peroxidase to the cell membrane. Protein release into the culture medium is also increased. These results can be explained either by an absence of fusion between phagosomes and lysosomes, or by an inhibition of the discharge of peroxidase adsorbed to the phagosomal membrane after fusion.

Animals↗
PubMed1977

Purification of rat liver particulate neutral ribonuclease and comparison of properties with pancreas and serum ribonucleases.

Rat liver particulate neutral ribonuclease (EC 3.1.4.22) was extensively purified (up to 40000-fold). It is shown to be an endonuclease, specific for pyrimidine bases, hydrolysing 5'-phosphate ester bonds. The enzyme specificity, Km, pH optimum, stability in acid medium and thermal stability at high temperature are the same as those of rat pancreatic and serum ribonucleases. Like pancreatic and serum neutral ribonucleases, the hepatic enzyme is sensitive to the liver natural inhibitor. This inhibitor was purified 8000-fold; its association with ribonuclease follows zero-order kinetics. These identical properties for ribonuclease of rat liver, pancreas and serum support the hypothesis [Bartholeyns, Peeters-Joris & Baudhuin (1975) Eur. J. Biochem. 60, 385-393] of an extrahepatic origin for the liver enzyme, the plasma ribonuclease of pancreatic origin being taken up by endocytosis in the liver. Neutral ribonuclease activity was detected in all rat organs investigated; its distribution among tissues is different from the distribution of the natural ribonuclear inhibitor.

Animals↗