tretinoin and 3-aminobenzamide

A new synthetic drug, benzamide riboside (BR) exhibited strong oncolytic activity against leukemic cells in the 5-10 microM range. Higher BR-concentrations (20 microM) predominantly induced necrosis which correlated with DNA strand breaks and subsequent depletion of ATP- and dATP levels. Replenishment of the ATP pool by addition of adenosine prevented necrosis and favoured apoptosis. This effect was not a pecularity of BR-treatment, but was reproduced with high concentrations of all trans-retinoic acid (120 microM) and cyanide (20 mM). Glucose was also capable to suppress necrosis and to favour apoptosis of HL-60 cells, which had been treated with necrotic doses of BR and cyanide. Apoptosis eliminates unwanted cells without affecting the microenvironment, whereas necrosis causes severe inflammation of surrounding tissues due to spillage of cell fluids into the peri-cellular space. Thus, the monitoring and maintenance of cellular energy pools during therapeutic drug treatment may help to minimize nonspecific side effects and to improve attempted drug effects.

Topics: Adenosine; Adenosine Triphosphate; Antineoplastic Agents; Apoptosis; Benzamides; Comet Assay; Deoxyadenine Nucleotides; Deoxycytosine Nucleotides; Deoxyribonucleotides; DNA Damage; Dose-Response Relationship, Drug; Enzyme Inhibitors; HL-60 Cells; Humans; IMP Dehydrogenase; Necrosis; Nucleosides; Poly(ADP-ribose) Polymerase Inhibitors; Potassium Cyanide; Tretinoin

NB4 cells, a model of acute promyelocytic leukemia have been shown to undergo granulocytic differentiation in response to all trans retinoic acid (ATRA), or monocytic differentiation in response to 1alpha,25 dihydroxyvitamin D(3) (1,25 D(3)) and phorbol ester. We have shown previously that the expression of poly(ADP-ribose) polymerase (PARP) is dramatically increased during monocytic differentiation and completely down-regulated during neutrophilic differentiation. Here we show that NB4 cells simultaneously treated with ATRA and isoquinolinediol (Iso-Q), a specific PARP inhibitor, fail to differentiate into neutrophils. Nitroblue tetrazolium (NBT) dye reduction was inhibited by 48% and neutrophil formation was reduced by 75%. NB4 cells treated with ATRA and Iso-Q instead showed features of apoptosis including nuclear condensation, DNA fragmentation, and PARP cleavage yielding a 85 kDa fragment. NB4 cells treated with ATRA in combination with 1,25 D(3), a monocytic differentiation inducer, while continuing to reduce NBT also failed to mature into neutrophils or monocytes and again showed features of apoptosis. Down-regulation of Bcl-2 protein expression was evident in NB4 cells treated with ATRA and ATRA in combination with Iso-Q or 1,25 D(3), but not in cells treated with a classic chemotherapeutic agent, arabinosycytosine, suggesting that Bcl-2 down-regulation is neither necessary, nor specific for apoptosis in this model.

Topics: Apoptosis; Benzamides; Calcitriol; Cell Differentiation; Cell Division; DNA Fragmentation; Enzyme Inhibitors; Humans; Isoquinolines; Leukemia, Promyelocytic, Acute; Poly(ADP-ribose) Polymerase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Quinolines; Tretinoin

Culture and differentiation parameters of a human thyroid transformed cell line (HuT) were analyzed. Treatment with high concentrations of chemical agents namely dimethyl sulphoxide and retinoic acid, exerted a dramatic cytotoxic effect. The exposure of these cells to the lowest doses of retinoic acid as well as to 8 mM-16 mM 3-aminobenzamide a potent inhibitor of poly(ADPribose)polymerase, resulted in a delay of cell proliferation. Poly(ADPribose)polymerase activity was differently affected by retinoic acid (stimulation) and 3-aminobenzamide (inhibition).

Topics: Benzamides; Cell Cycle; Cell Division; Cell Line, Transformed; Cell Survival; Dimethyl Sulfoxide; DNA; Female; Flow Cytometry; Humans; Microscopy, Electron; Middle Aged; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Simian virus 40; Thyroid Gland; Tretinoin

The effect of various differentiation-inducers on the activity of Ca2+, phospholipid-dependent protein kinase (C-kinase) activity and endogenous protein phosphorylation by the kinase were examined in the extracts of HL-60 cells. Although all of the inducers, retinoic acid, dibutyryl cAMP, nicotinamide, dimethylsulfoxide, and 3-aminobenzamide increased the cytosolic C-kinase activity accompanied with the differentiation into mature myelocytes, only retinoic acid markedly enhanced Ca2+, phospholipid-dependent phosphorylation of 44 and 32 kDa proteins in the cytosol. These results suggest that the differentiation pathway induced by retinoic acid is different from the pathways induced by other inducers.

Topics: Benzamides; Bucladesine; Calcium; Cell Differentiation; Cell Extracts; Cells, Cultured; Cytosol; Dimethyl Sulfoxide; Electrophoresis, Polyacrylamide Gel; Humans; Molecular Weight; Niacinamide; Phosphorylation; Protein Kinase C; Proteins; Tretinoin

We investigated the influence of the poly(ADP-ribose) polymerase inhibitor 3-aminobenzamide (ABA) on induction of phenotypic markers of granulocyte differentiation by retinoic acid and markers of macrophage differentiation by TPA in HL-60 cells. The differentiation of HL-60 cells towards the granulocyte lineage was assessed by hexose monophosphate shunt activity, proportion of cells capable of reducing NBT dye, and the appearance of recognizable neutrophils and bands. The effect of ABA and retinoic acid on NBT dye reduction and appearance of mature neutrophils and bands was synergistic, whereas the effects of these agents on hexose monophosphate shunt activity were additive. The differentiation inducing capacity of ABA in the presence of retinoic acid was dose-related. The influence of ABA on TPA-induced markers of macrophage differentiation was assessed by determining the proportion of adherent cells produced after treatment and by measuring acid phosphatase activity in the adherent cell fraction. In the presence of ABA, the number of cells adhering to plastic declined after day 2 of exposure to TPA, and acid phosphatase activity in adherent cells was inhibited fourfold (p = 0.01). The influence of ABA on the phenotypic markers of granulocyte and macrophage differentiation was detectable at concentrations that were not cytotoxic. The influence of ABA on HL-60 differentiation is similar to that previously reported for human bone marrow CFU-GM. Our data suggest that poly(ADP-ribose) polymerase plays a role in differentiation of HL-60 cells and that HL-60 might provide a useful model for evaluating control mechanisms involved in the differentiation of CFU-GM.

Topics: Acid Phosphatase; Benzamides; Cell Differentiation; Cell Line; Granulocytes; Hematopoietic Stem Cells; Humans; Isoniazid; Leukemia, Myeloid, Acute; Macrophages; Poly(ADP-ribose) Polymerase Inhibitors; Tetradecanoylphorbol Acetate; Tretinoin

Poly(ADP-ribose) synthesizing activity in mouse teratocarcinoma EC-A1 cells decreased markedly during differentiation induced by retinoic acid; the activities assayed in permeabilized cells decreased to 25% and 10% of the activity of control (uninduced cells) 2 and 3 days, respectively, after the addition of 0.1 microM retinoic acid to the culture medium. This change preceded changes in morphology and DNA synthesis, which became prominent after 4 days. The decrease in poly(ADP-ribose) synthesizing activity appeared to be caused by a diminution of the synthetase protein and not by a decrease in its catalytic activity, because the full activity disclosed by DNase I treatment decreased in parallel, albeit at about 20 times higher levels. When 8 mM 3-aminobenzamide or 10 mM nicotinamide, specific inhibitors of poly(ADP-ribose) synthetase, was added to the culture medium, the cells underwent differentiation after 7-9 days. An analogue, 3-aminobenzoic acid, which is not inhibitory to the synthetase, induced differentiation much less efficiently than did 3-aminobenzamide, and the effect of 3-aminobenzoic acid appeared to be ascribable to its potent cytotoxicity. Immunohistochemical analysis using anti-poly(ADP-ribose) antibody confirmed the marked reduction in poly(ADP-ribose) synthesizing activity in nuclei of the cells treated with retinoic acid or 3-aminobenzamide but not with 3-aminobenzoic acid. These results suggest that a decrease in poly(ADP-ribose) synthesis triggers differentiation of teratocarcinoma cells.

Topics: Aminobenzoates; Animals; Benzamides; Cell Differentiation; Cell Division; Cell Survival; Cells, Cultured; DNA Replication; Mice; NAD+ Nucleosidase; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Teratoma; Tretinoin