Effect Of Daunomycin Research Articles

Evidence for the genotoxic effect of daunomycin in multipotent hematopoietic cells of mouse bone marrow: Chromatin proteins analysis

Severe bone marrow suppression and anemia are the main side effects of using chemotherapeutic agents like daunomycin. In this study the effect of daunomycin on viability and chromosomal proteins of multipotent hematopoietic cells (MHCs) of mouse bone marrow was investigated. The cells were separated from mature cells according to their adherence, incubated in the absence and presence of various concentrations of daunomycin and viability was determined by trypan blue exclusion and MTT assay. The histones and high mobility group (HMG) proteins were extracted by acid and salt, respectively and analyzed on SDS-PAGE and immunoblot. The results revealed that daunomycin exhibited time and dose dependent cytotoxicity on the cells and upon increasing the concentrations of drug, the extractability of histone and HMG proteins decreased. Agarose gel electrophoresis showed aggregation of DNA in the presence of drug. Flow cytometry analysis suggested that there are differences in type and amount of histones H2A and H2B of these cells in comparison with thymus histones. Moreover histone H3 was not subjected to trimethylation at lysine 9 and daunomycin decreased H3K9 dimethylation and H3K9 acetylation in these cells in a dose-dependent manner. From these results it is concluded that the binding of daunomycin to chromatin precedes chromatin of multipotent hematopoietic cells of bone marrow into compaction/aggregation and beside DNA, histones and HMG proteins also play an important role in this process.

An in vitreo study of the effect of daunomycin on human lens epithelial cells in culture

An in vitreo study of the effect of daunomycin on human lens epithelial cells in culture

Daunomycin inverts the long-range chirality of DNA condensed states

The effect of daunomycin upon DNA condensed states induced by poly(ethylene glycol) (PEG) was studied by circular dichroism (CD) and circular intensity differential scattering (CIDS). The CD spectra of these aggregates showed psi-type anomalies and intensities 10-100 times greater than those obtained with the dispersed DNA solutions in the absence of PEG. Increasing concentrations of daunomycin, added to the DNA solution prior to its aggregation, led, in the presence of PEG, to CD and CIDS signals which gradually decreased in magnitude and eventually inverted sign. The coincidence of the transition point of both signals and a careful characterization of the CD spectrum at the transition point clearly indicated that the inversion observed corresponds to an inversion of the handedness of the aggregates. The latter result suggests that the structure of the aggregates at the inversion point should resemble that of a nematic liquid-crystalline structure. The characteristic B-DNA spectrum obtained in this case further suggests that the packing process does not affect the secondary structure of the DNA molecules and that small changes in their local structure can induce dramatic changes in their long-range tertiary packing. The results obtained in this study represent a confirmation of a recent theory of psi-type CD in which the anomalous signals are interpreted as a manifestation of the long-range chirality of the aggregates.

Inhibition of the RNA polymerase-catalyzed synthesis of RNA by daunomycin. Effect of the inhibitor on the late steps of RNA chain initiation.

In vitro RNA synthesis from the A promoters of T7 bacteriophage by Escherichia coli RNA polymerase is strongly inhibited by daunomycin. Under the conditions of the assay for total RNA synthesis, daunomycin has no effect on the formation of the binary enzyme-template complex. The major inhibitory effect may be exerted during incorporation of the first few nucleotides into the nascent RNA chain. We report here that daunomycin has little effect on the substeps leading to the formation of abortive dinucleotide from the A promoters. A large part of the inhibitory effect of daunomycin is therefore specifically targeted toward a very small final portion of the process of initiation, which may be described as the addition of nucleotides to the initial dinucleotide (and its subsequent translocation) until a stable ternary complex has been formed. The level at which this inhibition is exerted is more precisely defined by examining the effect of daunomycin on the synthesis of the first few oligonucleotides synthesized from the A3 promoter. The major inhibitory effect of daunomycin is found to be specifically exerted during the transformation of the initial dinucleotide to the corresponding trinucleotide. The remainder of the inhibition may be evenly divided among a large number of nucleotide addition steps that transform the nascent trinucleotide to a completed RNA chain. One of the fundamental levels at which transcription is controlled is initiation. In slow-start promoters, e.g. the lac UV5 promoter, the late stages of initiation (when the enzyme has the option of either producing an abortive di- or trinucleotide or proceeding with the formation of a stable ternary complex) may be involved in this control. Inhibitors which specifically act on this stage of initiation may thus prove useful for the study of such systems, as well as transcription in general.

A free radical scavenger role for daunomycin: Inhibition of nonenzymatic oxidation of NADH

The effect of daunomycin(Dm) on the nonenzymatic oxidation of NADH in the presence of metal ions, H 2O 2 and various ligands was examined. The results show that daunomycin inhibits the oxidation of NADH by reacting with one or more of the reaction intermediates which include OH •, HO 2 • , O 2 • and NAD •. This reaction is a reductive one involving the anthraquinone moiety of daunomycin as confirmed by control experiments by comparative UV-Vis analysis of the spectral character of daunomycin after reduction by NaBH 4. Daunomycin, once reduced, apparently does not transfer its electron to another species such as O 2 and is thus thought to play the role of free radical scavenger.

Modifiers of Radiation Action on DNA Screened by Analytical Ultracentrifugation

The effect of daunomycin, chromomycin A/sub 3/, anthramycin, cis-dichlorodiammineplatinum(II) (cisplatin), mitomycin C, and chloroquine on the frequency of radioninduced strand breaks in X-irradiated aqueous solutions of DNA was studied primarily by analytical ultracentrifugation using the sedimentation velocity method. The results show a potent radiosensitizing effect for daunomycin and chromomycin, a protective action for chloroquine and mitomycin, and a nonmodifying effect for anthramycin. Cisplatin forms a highly aggregated complex with DNA which prevents this kind of study.

Effect of Daunomycin on Myocardial Contractility and on the Action of β-Methyldigoxin

In isolated electrically driven guinea pig left atria daunomycin at concentrations of 50-200 microgram/ml reduced the contraction. In the presence of daunomycin the positive inotropic effect of beta-methyldigoxin was reduced and, at higher concentration of daunomycin, contractility was inherited.

Effect of daunomycin, adriamycin and its congener AD 32 on the activity of DNase I from bovine pancreas

Effect of daunomycin, adriamycin and its congener AD 32 on the activity of DNase I from bovine pancreas

The effect of daunomycin on cell proliferation and protein synthesis of human leukemic blast cells

The effect of daunomycin (DMC) (about 1·5 mg/kg body weight) on cytokinetic parameters and 3 H-leucine incorporation of leukemic blast cells in bone marrow and blood was studied at intervals up to 96 hr after DMC in 5 patients, 4 with AML and 1 with AUL. In all cases the MI showed a decrease 6–12 hr after DMC. The 3 H-TDR values declined at various times ( 12–96 hr after) DMC. The depression of the MI and the 3 H-TDR LI was long-lasting and pretreatment values were not yet reached by 72–96 hr after DMC. The incorporation of 3 H-leucine into human leukemic blast cells was shown to be inhibited by DMC late ( 72–96 hr) after drug administration in four out of five patients. The late decrease in leucine incorporation suggests that DMC besides an immediate direct killing effect seen from the decrease in the number of circulating blast cells in the peripheral blood also has a late inhibiting effect on LBC. The late effect suggests that protein synthesis is reduced secondary to effects on DNA and/or RNA synthesis.

Correlation between fixation of daunomycin-H 3 and antimitotic and antimetabolic activity in ascitic sarcoma 180

Daunomycin uptake and its antimitotic and antimetabolic activities have been studied in S 180 ascites cells in vivo. The uptake of the tritiated antibiotic was determined by radiochemical methods 15 min and 2 h after the i. p. administration of scalar doses. The inhibiting effects on nucleic acids biosynthesis was evaluated by determining with autoradiographic and radiochemical methods, the incorporation of 3H-thymidine and 3H-uridine 2 h after daunomycin administration. Parallel studies were carried out on the antimitotic activity. The results obtained indicate that daunomycin is already present in the cells 15 min after injection and in proportion to the dose given. Two hours after the injection the level of incorporated radioactivity is lower. Mitotic activity, measured two h after the treatment, is reduced dose proportionally and is completely absent at doses of 2 mg/kg. The incorporation of 3H-thymidine and 3H-uridine is increased in the cells treated with low doses and is reduced only at doses of 2 mg/kg or higher. In these experimental conditions DNA synthesis is reduced to greater extent than RNA synthesis. A comparison of daunomycin uptake and of nucleic acid synthesis inhibition showed a direct proportionality whereas the effect of daunomycin on mitotic activity and on nucleic acids metabolism appear to be dissociated.

Studies on the Effect of Association of Daunomycin and X-Rays on Oberling-Guérin-Guérin Transplantable Myeloma

The effect of daunomycin and x-rays in association on the survival time of Long Evans and Wistar rats with Oberling-Guérin-Guérin transplantable myeloma is studied. No favorable results were obtained in Wistar rats, whereas in Long Evans rats the association proved more effective than one treatment alone. In Long Evans rats histoincompatibility phenomena against the tumor may be a cause of the enhanced effect of the association under study. The experimental results are discussed in relation to the use of this association in clinical treatment.

The effect of daunomycin on human cells in vivo and in vitro.

Cytogenetic and morphologic abnormalities in bone marrow and peripheral blood and biochemical changes in peripheral blood leukocytes were studied after in-vivo and in-vitro treatment with daunomycin. Seven patients with acute lymphocytic or granulocytic leukemia were studied; the total dose varied from 80 to 420 mg/m2. The highest percentage of major chromosomal aberrations (80 to 90%) appeared right after treatment in vivo. These aberrations disappeared within 1 or 2 weeks and consisted of chromatid breaks, fragments, chromatid exchanges, ring chromosomes, dicentrics or extensive fragments. Prominent morphologic abnormalities included megaloblastic transformation of both the myeloid and erythroid series and increased cytoplasmic vacuolization. Aneuploid cells lines from two patients showed less change after daunomycin treatment than did normal diploid cells. The daunomycin dose threshold in vitro was narrow: 3 pg/ml of culture caused death of the entire cell population, while 0.03 pg/ml of culture produced little chromosomal damage. The in-vitro studies on normal human lymphocytes indicate that daunomycin affects RNA and DNA synthesis and that it interferes with the cell cycle during the G2 period. This drug appears to have the unique capacity to delay the onset of mitosis in cells which have already synthesized DNA.

Daunomycin-induced chromosomal aberrations and the influence of arginine in modifying the effect of the drug

The effect of Daunomycin (Dm)—a new antibiotic—was studied on human chromosomes. Chromatid and chromosome aberrations were recorded. Chromatid exchanges appear to be in preponderance over free acentric fragments. It is suggested that Dm favors the reunion of broken ends by cross-linking DNA strands. When Dm is supplemented with arginine, the mitotic index as well as the frequency of chromosome aberrations is increased. The mechanism of action of the Daunomycin+arginine mixture is not quite clear. After 24 h of treatment, DNA synthesis was observed in cells treated with 0.02 μg Dm/ml+0.16% arginine but not cells treated with 0.02 μg Dm/ml alone. In the former treatment, rapidity of DNA synthesis was as high as in untreated cells, but the frequency of labelled cells was reduced by about two-thirds. There may exist an “all or none” relationship between Dm and DNA synthesis.

Synergic effect of daunomycin and immunization on the growth of transplantable tumors

By immunization with antigenic fractions obtained from the tumor, injected in the presence of Freund complete adjuvant, it is possible to obtain an immunological reaction against the implantation of Sarcoma 180 in albino Swiss mice. The treatment with the antibiotic Daunomycin, some days after the implantation of the tumor in immunized mice, produces an inhibiting effect on the tumor growth significantly higher than that due to the immunization or to the drug alone. The synergistic effect is more relevant with the low dosage of the antibiotic than with the higher one. This behavior may be related to the depressing activity of the drug towards lymphopoietic tissues.

ACTION OF DAUNOMYCIN ON THE NUCLEIC METABOLISM OF EHRLICH ASCITES TUMOR

The effect of Daunomycin, a new antibiotic with antitumor activity, on the metabolism of nucleic acids of Ehrlich ascites tumor cells was studied with autoradiographic techniques. Daunomycin injected intraperitoneally at the dose of 4 mg/kg body weight did not affect the uptake of tritiated thymidine, although the mitotic index of the tumor cells was decreased. The nuclear RNA synthesis, particularly the RNA fraction which is synthetised on the chromosomes, was partially inhibited.