Adriamycin induced changes in translocation of sodium ions in transporting epithelial cells

Response to adriamycin of transplasma membrane electron transport in adriamycin-resistant and nonresistant HL-60 cells

Adriamycin, 10(-8) - 10(-5) M, inhibited transplasma membrane electron transport of uninduced HL-60 cells susceptible to adriamycin and not in uninduced HL-60 cells resistant to adriamycin as measured by reduction of external ascorbate free radical. Electron flow across the plasma membrane was measured with the intact living cells by means of a simple assay procedure whereby the transported electrons were captured by ascorbate free radical to slow the rate of chemical oxidation of ascorbate. The response to adriamycin was rapid with maximum inhibition in less than 1 min. Preincubation was not required and the inhibition presumably was not mediated through effects on DNA replication or transcription. Except at the highest concentration tested of 10 microM, both transplasma membrane electron transport and growth were unaffected by adriamycin with a line of HeLa cells resistant to the drug. The findings provide evidence, using a physiological acceptor, ascorbate free radical, for a direct inhibition of transmembrane electron transport of HL-60 cells by adriamycin that correlates closely with adriamycin inhibition of cell growth. The lack of response with resistant cells suggests an alternative mechanism for adriamycin resistance not necessarily based on transport control.

Inhibition of transplasma membrane electron transport by transferrin-adriamycin conjugates

Transplasma membrane electron transport from HeLa cells, measured by reduction of ferricyanide or diferric transferrin in the presence of bathophenanthroline disulfonate, is inhibited by low concentrations of adriamycin and adriamycin conjugated to diferric transferrin. Inhibition with the conjugate is observed at one-tenth the concentration required for adriamycin inhibition. The inhibitory action of the conjugate appears to be at the plasma membrane since (a) the conjugate does not transfer adriamycin to the nucleus, (b) the inhibition is observed within three minutes of addition to cells, and (c) the inhibition is observed with NADH dehydrogenase and oxidase activities of isolated plasma membranes. Cytostatic effects of the compounds on HeLa cells show the same concentration dependence as for enzyme inhibition. The adriamycin-ferric transferrin conjugate provides a more effective tool for inhibition of the plasma membrane electron transport than is given by the free drug.

Cell surface actions of adriamycin

Adriamycin has a vast range of reported actions on the structural and functional properties of cells. This review summarizes the literature on the ability of the drug to modulate the cell surface membrane and attempts to address the question of how such actions could be linked to cytotoxicity. In addition, we consider the use of polymer immobilization of adriamycin to separate intracellular from plasma membrane effects of the drug, and show how this approach has been helpful in interpreting the pharmacology of adriamycin. Finally, a range of biophysical and spectroscopic approaches to defining the molecular details of adriamycin-bilayer interactions is surveyed, and the results used to discuss a model for how this antineoplastic agent binds to membranes.

Interaction of anthracyclinic antibiotics with cytoskeletal components of cultured carcinoma cells (CG5)

The effects of doxorubicin (adriamycin, ADR) and daunorubicin (daunomycin, DAU), two anthracyclinic antibiotics, on a human breast carcinoma cell line (CG5) were studied by cytochemical and morphological methods. Both ADR and DAU were capable of inducing the multinucleation and spreading phenomena, associated with a decrease of the cell growth rate. DAU appeared to be more effective than ADR at the tested concentrations (10(-5), 5 x 10(-5) mM), in affecting the cell growth as well as in inducing multinucleation. As revealed by scanning electron microscopy, spreading and multinucleation were accompanied by a remarkable redistribution of surface structures. Moreover, a dose- and time-dependent rearrangement of the underlying cytoskeletal components was clearly detected. In addition, both ADR and DAU at 5 x 10(-5) mM seemed to favor the rebuilding of microtubules after treatment with colcemid, while a higher dose (10(-4) mM) exerted the opposite effect. Furthermore, both anthracyclines prevented the action of the antimicrotubular agent. When recovered after treatment with cytochalasin B, in presence of ADR (or DAU) (5 x 10(-5), 10(-4) mM), cells showed a microfilament pattern rearranged differently as compared to that of cells recovered in anthracycline-free medium. The results reported here strongly suggest the involvement of actin and tubulin in CG5 cell response to ADR and DAU treatments. Thus, the cytoskeletal apparatus is confirmed as another target involved in the mechanism of action of anthracyclines.

Induction, by adriamycin and mitomycin C, of modifications in lipid composition, size distribution, membrane fluidity and permeability of cultured RDM4 lymphoma cells

Adriamycin and mitomycin C were previously found to modulate the sensitivity of lymphoma cells to lysis by certain effectors of immunity and this modulation was dependent on drug concentration. In the present studies, RDM4 lymphoma cells were treated with different concentrations of the two drugs for 24 h in culture. These treatments resulted in changes in the lipid composition, membrane fluidity, cell size distribution, and permeability to 51CrO4, Trypan blue, Acridine orange and trimethylaminodiphenylhexatriene (TMA-DPH) of the cells. Changes in some of these parameters, as a function of drug concentration, resulted in dose-response curves which were bell-like shaped, hence paradoxical similarities between non-drug-treated cells and cells treated with higher drug concentrations were observed.

Effect of adriamycin on experimental proliferative vitreoretinopathy in the rabbit

The cell injection model of proliferative vitreoretinopathy (PVR) in the rabbit was used to study the therapeutic value of intravitreal adriamycin (doxorubicin). Adriamycin in a dose of 10 nmol per eye, if injected at the same time as the cells, controls PVR. At the cell doses used, PVR is not affected if there is a time interval between cell and drug injection. Because of retinal toxicity, as evidenced by electroretinographic and histopathologic changes, the beneficial effects of adriamycin on membrane formation cannot be exploited at this time.

Investigations of the action of the antitumour drug adriamycin on tumour cell membrane functions--I

The membrane potential of L1210 murine leukemia cells was assessed by use of the tritiated lipophilic cation probe triphenylmethylphosphonium bromide. The potassium equilibrium potential of the cells was found to be -71 +/- 7 mV. The resting membrane potential was partly dissipated by the protonophore m-chlorocarbonylcyanidephenylhydrazone (10 microM), but was unaffected by ouabain (1 mM) and apparently by the calcium ionophore A23187 (2.5 microM). Monensin (20 microM) caused a hyperpolarization which, since it was blocked by ouabain, was presumed to be brought about by activation of the Na+K+-ATPase via an elevated cytoplasmic Na+ concentration. Adriamycin at concentrations as high as 5 X 10(-4) M brought about no change in the resting potential of the cells. Also, cytotoxic concentrations of adriamycin, unlike ouabain, had no effect on rubidium-86 transport into L1210 cells, nor upon a monensin-induced increased in rubidium-86 uptake. The results suggest that although adriamycin is capable of interaction with the plasma membrane, and may exert its cytotoxicity at this locus, changes in ion flux mediated by Na+K+-ATPase or those capable of changing the membrane potential do not appear to be implicated in its mechanism of action.

The binding of actinomycin D and Adriamycin to supercoiled DNA, single-stranded DNA and polynucleotides

The effect of actinomycin D and adriamycin on synthetic polynucleotides, single-stranded viral DNA and supercoiled DNA has been studied employing the fluorescent probe, terbium. Marked displacement of the probe was observed when any deoxyribose-containing polynucleotide was pretreated with either drug. With supercoiled DNA, an unwinding of the supercoil was observed at very low drug concentrations (at approx. 1:500 molar ratio of drug:DNA) prior to the displacement of the terbium. This unwinding was visualized by agarose gel electrophoresis at molar ratios of approx. 1:200. The effect was more apparent and occurred at lower drug: DNA ratios with actinomycin D than with adriamycin. Unlike cis-dichlorodiammine platinum(II), actinomycin D did not protect pBR322 DNA from cleavage at its BamHI site. The hydrolysis of phi chi 174 DNA by a series of G-C-specific restriction nucleases (including HhaI, HpaII and HaeIII) was also not affected by prior treatment of the DNA with actinomycin D.

Adriamycin inhibits PTH-mediated but not PGE2-mediated stimulation of cyclic AMP formation in isolated bone cells

We have examined the effect of adriamycin, an anthracycline antibiotic which modifies plasma membrane functions, on the cyclic AMP response to PTH and PGE2 in isolated osteoblastlike cells. Adriamycin blunted the increment in bone cell cyclic AMP caused by exposure to PTH. This effect appeared rapidly (within 3 min after bone cells were exposed to adriamycin) and disappeared soon after exposure of adriamycin-treated cells to adriamycin-free incubation medium. Inhibition was evident over the entire time course of PTH action, at low as well as high PTH concentrations, and was one-half maximal at 31 microM adriamycin. It could not be attributed to alterations in cyclic AMP exodus, degradation or interference with the cyclic AMP assay, nor to impaired cell viability. Adriamycin also reduced the stimulatory effect of PTH on adenylate cyclase activity in a crude plasma membrane preparation. By contrast, adriamycin failed to modify the effects of PGE2 on cyclic AMP generation in intact bone cells, and on adenylate cyclase activity in broken cells. Moreover, concentrations of adriamycin that blunted the effect of PTH on adenylate cyclase activity did not inhibit the stimulatory effects of sodium fluoride or of GppNHp. These results suggest that adriamycin selectively alters the interaction between PTH and its receptor or impairs the transmission of information from hormone-receptor complex to adenylate cyclase (or both), perhaps by binding to specific lipid domains in the plasma membrane. Structural analogues of adriamycin, which vary in their lipophilic properties, also varied in their capacity to perturb the cyclic AMP response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adriamycin-induced changes in the surface membrane of sarcoma 180 ascites cells

Adriamycin increases (a) the rate of agglutination of Sarcoma 180 cells by concanavalin A after brief exposure of 2-3 h and (b) membrane fluidity as measured by ESR within 30 min of exposure at concentrations of the anthracycline of 10(-7)-10(-5) M. The effect of adriamycin on agglutination is not due to an increase in the number of surface receptors for concanavalin A, since the extent of binding of the lectin is not altered by adriamycin and no change occurs in the rate of occupancy of the concanavalin A binding sites by the lectin in cells treated with the antibiotic. The order parameter, a measurement of membrane fluidity, decreases in cells exposed to adriamycin and is dose-related. The results indicate that adriamycin can induce changes in the surface membrane of Sarcoma 180 cells within a brief period of exposure to a low but cytotoxic level of this agent.

The effects of adriamycin (doxorubicin HCl) on human red blood cells

We have studied the effects of adriamycin (doxorubicin HCl) on human red blood cells. The peroxidizing effect of adriamycin on the thiols of red cell constituents resulted in decreased glutathione stability, and oxidation of hemoglobin and membrane protein components 1, 2, and 3, forming large molecular weight complexes. Membrane lipids were also peroxidized. Adriamycin itself did not inhibit the enzymes of the reductions system (glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, glutathione reductase, glutathione peroxidase, catalase, superoxide dismutase) of the red cells. Because adriamycin has the potential of inhibiting ATPase, including both Na-K-dependent ATPase and ouabain insensitive ATPase, at concentrations not inhibitory to other enzymes, the net sodium content increased, and potassium content decreased after incubation of red cells with adriamycin at high concentrations. The experimental results described with adriamycin may serve as a model for the possible mechanism of cardiotoxicity observed in its clinical use, and also explain the potential hemolyzing effect on red cells. There was greater oxidizing effect on glucose-6-phosphate dehydrogenase (G-6-PD) deficient than on normal erythrocytes. It is suggested that adriamycin be used with caution in individuals with G-6-PD deficient red cells.