Mechanism of acute anthracycline cardiotoxicity in isolated rat hearts: carminomycin versus daunomycin.

Cardiotoxicity limits the use of anthracyclines which are potent anticancer agents. In the isolated rat heart, we investigated the mechanism of acute anthracycline cardiotoxicity and compared a new anthracycline, carminomycin, with daunomycin which is in established use. Daunomycin 1.75 X 10(-5) M produced a fall in cardiac output (36 +/- 2 versus 58 +/- 1 ml/min; p less than 0.01), left ventricular power production (9 +/- 0.7 versus 16 +/- 0.3 mJ/sec/g; p less than 0.01), and efficiency of heart work (3.3 +/- 0.2 versus 6.3 +/- 0.2 mJ/sec/ml O2; p less than 0.01; mean +/- S.E. 40 min after daunomycin). Carminomycin (1.75 X 10(-5) M) produced a greater fall in cardiac output than equimolar daunomycin (26 +/- 2 versus 36 +/- 2 ml/min; p less than 0.01). Daunomycin did not reduce coronary flow rate, heart rate, or oxygen consumption. From the preceding data, we inferred that, since afterload and preload were constant in this model, heart failure was due to a depressed inotropic state. Procedures that increased cytosolic calcium relieved heart failure namely, pretreatment with digoxin (62.4 micrograms), isoproterenol (10(-6) M), and increased perfusate Ca2+ (5 mM versus 2.5 mM) all prevented carminomycin-induced fall in cardiac output (41 +/- 1, 47 +/- 5, and 52 +/- 1, respectively, versus 26 +/- 2 ml/min; p less than 0.01). Acute anthracycline contractile failure was also associated with a fall in high-energy phosphate compounds which could also have contributed to the decreased inotropic state. We conclude that carminomycin is more cardiotoxic than daunomycin in equimolar concentrations and that a lowered cytosolic calcium and decreased energy stores might cause the contractile failure. The cytosolic calcium and high-energy phosphate compounds were lowered by separate mechanisms.

Comparative cardiotoxicity of doxorubicin and a morpholino anthracycline derivative (KRN8602).

The toxicities of doxorubicin (DXR) and 3'-deamino-3'-morpholino-13-deoxy-10-hydroxycarcminomycin (KRN8602) were compared in perfused rat heart preparations. In addition, their toxicities in isolated myocytes as well as their abilities to cause oxidation of intracellular reduced glutathione (GSH) were evaluated. Finally, their capacities to initiate oxygen consumption and lipid peroxidation in isolated microsomes were determined. DXR caused a dramatic decrease in left ventricular pressure in the perfused hearts and a leak of lactic acid dehydrogenase (LDH) from isolated myocytes. These effects were not observed with KRN8602 at comparable concentrations although KRN8602 caused oxidation of GSH to oxidized glutathione (GSSG) in the myocytes. Both anthracyclines caused an increase in oxygen consumption and lipid peroxidation in isolated microsomes although these effects were more pronounced with KRN8602. The results of these experiments demonstrate that, despite the high capacity to redox cycle and to generate oxygen-derived oxidants, KRN8602 exhibited no measurable cardiotoxicity. The findings are consistent with a view that, if the formation of such oxidants is central to the cardiotoxicity of DXR, these substances must be formed in cellular compartments, e.g. plasma membranes, where the morpholino derivative (KRN8602) does not accumulate.

Differential single- versus double-strand DNA breakage produced by doxorubicin and its morpholinyl analogues.

The morpholinyl analogues of doxorubicin (DOX) have previously been reported to be non-cross-resistant in multidrug resistant (MDR) cells due to a lower affinity for P-glycoprotein relative to the parent compound. In order to further investigate the mechanisms of action of these morpholinyl anthracyclines, we examined their ability to cause DNA single- and double-strand breaks (SSB, DSB) and their interactions with topoisomerases. Alkaline elution curves were determined after 2-h drug treatment at 0.5, 2 and 5 microM, while neutral elution was conducted at 5, 10 and 25 microM in a human ovarian cell line, ES-2. A pulse-field gel electrophoresis assay was used to confirm the neutral elution data under the same conditions. Further, K-SDS precipitation and topoisomerase drug inhibition assays were used to determine the effects of DOX and the morpholinyl analogues on topoisomerase (Topo) I and II. Under deproteinated elution conditions (pH 12.1), DOX, morpholinyl DOX (MRA), methoxy-morpholinyl DOX (MMDX) and morpholinyl oxaunomycin (MX2) were equipotent at causing SSB in the human ovarian carcinoma cell line, ES-2. However, neutral elution (pH 9.6) under deproteinated conditions revealed marked differences in the degree of DNA DSB. After 2-h drug exposures at 10 microM, DSBs were 3300 rad equivalents for MX2, 1500 for DOX and 400 for both MRA and MMDX in the ES-2 cell line. Pulse-field data substantiated these differences in DSBs, with breaks easily detected after MX2 and DOX treatment, but not with MRA and MMDX. DOX and MX2 thus cause DNA strand breaks selectively through interaction with Topo II, but not Topo I. In contrast, MRA and MMDX cause DNA breaks through interactions with both topoisomerases with a predominant inhibition of Topo I.

Anthraquinone-induced cell injury: acute toxicity of carminomycin, epirubicin, idarubicin and mitoxantrone in isolated cardiomyocytes.

Acute toxic effects of the antineoplastic anthraquinones carminomycin, epirubicin, idarubicin and mitoxantrone were studied in primary cultures of cardiomyocytes, which were isolated from adult rats. Both time- and concentration-dependent changes of cell structure and viability (trypan blue exclusion) following incubation of myocytes with subclinical, clinical and toxic concentrations of the anthraquinones were examined by light microscopy. The area under the decay curve of viable and rod-shaped myocytes was used to express cytotoxicity of the drugs. Mitoxantrone was found to reduce cell viability and number of rod-shaped cells to the greatest extent, followed by carminomycin, idarubicin and epirubicin. A significantly lower accumulation in cardiomyocytes was obtained with epirubicin and idarubicin compared with carminomycin. An inhibitory effect on oxygen consumption by the cells occurred already at 0.1 microM with epirubicin, whereas inhibition caused by other anthraquinones was less pronounced. Our data indicate a weak association of net accumulation and the toxicity parameter IC50 for carminomycin and idarubicin. In contrast to these results, a more significant correlation of cytotoxicity and anthraquinone lipophilicity was found, which suggests that the lipophilic character of a particular anthraquinone may be an important factor in drug-induced acute cardiotoxicity.

[Colony-forming ability of bone marrow hematopoietic cells in mice with transplanted leukemia during administration of carminomycin]. / Kolonieobrazuiushchaia sposobnost' gemopoéticheskikh kletok kostnogo mozga myshei s perevivnym leikozom pri vvedenii karminomitsina.

Effects of carminomycin on the colony-forming ability of bone marrow haemopoietic stem cells (CFUs) were compared in normal mice with steady state and actively regenerating bone marrow, and in P-388 and La leukemia-bearing mice. CFUs assays were performed 24 h after treatment of donor mice with the increasing doses of the drug. Leukemia-bearing mice received carminomycin on the 5th day after transplantation. The dose-effect curves were exponential for CFUS normal mice with both the steady state and active proliferation state of bone marrow. The maximal effect was found 24 h after injection of 0.7 mg/kg of carminomycin (ED50 for CFUS) being more pronounced in regenerating bone marrow. The dose-effect curves for leukemias were also exponential. In the case of La leukemia the killing of CFUs by carminomycin was the highest as compared with P-388 leukemia.

[Decrease in the blood toxicity of antitumor preparations during enterosorption]. / Snizhenie gematotoksichnosti protivoopukholevykh preparatov pri énterosorbtsii.

It is shown that peroral administration of activated charcoal SCN in rats with subcutaneously grafted Guerin carcinoma and Svec erythroleucosis does not hamper the antitumoural action of cyclophosphamide, methotrexate, and carminomycin and provides a protective effect on the medullar haemopoiesis.

[Effect of carminomycin on the enzyme systems of the metabolism of active forms of oxygen and on free-radical lipid oxidation in August rats with Walker carcinosarcoma 256]. / Vliianie karminomitsina na fermentnye sistemy metabolizma aktivnykh form kisloroda i svobodnoradikal'noe okislenie lipidov u krys linii August s kartsinosarkomoi Uoker 256.

The influence of carminomycin (CM) on enzymic systems of metabolism of oxygen active forms, free radical lipid peroxidation and microviscosity of membrane lipids as well as toxic and antitumour action of CM were studied in normal and tumour-bearing rats. Detected responses of the system of superoxide anion- and H2O2 metabolism reflected the role of active oxygen forms in CM toxicity. The investigation results of the lipid peroxidation fluorescent products level and microsomal lipid phase microviscosity did not suppose stimulation of lipid peroxidation as key mechanism for CM toxic effects. Problems on the prevention and treatment of anthracyclines side effects are discussed.

[Genotoxic and mutagenic activity of antineoplastic anthracyclines and their aglycones: study in two test-systems]. / Genotoksicheskaia i mutagennaia aktivnost' protivoopukholevykh antratsiklinov i ikh aglikonov: izuchenie v test-sistemakh.

Mutagenic (Ames tests) and genotoxic (SOS chromotest) activities of highly-efficient natural anthracycline monosaccharides possessing antitumor activity-daunorubicin (also known as daunomycin or rubomycin), doxorubicin (adriamycin), and carminomycin-were studied. At the same time, the hypothesis was tested that intercalation of the antibiotic moiety into the helix of cell DNA, which was mediated by the saccharide amino group, played a crucial role in genotoxicity of these anthracyclines. The hydrolysis products of these antibiotics (the corresponding aglycones) and aclacynomycin A (an anthracycline trisaccharide), as well as aclavinone (its derivative aglycone), were studied. All these compounds lacked the saccharide amino group necessary for intercalation. It was found that all anthracycline monosaccharides studied had a strong mutagenic effect on strain TA98 and a moderate effect on strain TA100 of Salmonella typhimurium. Aclacynomycin A was found to have no mutagenic effect on any strain. Lack of the glycoside amino group did not necessarily result in loss of mutagenic activity in the derivative aglycones of anthracycline monosaccharides: they exhibited moderate mutagenic activity in strain TA98 and low but significant activity in strain TA100. The S9 microsomal fraction did not alter the mutagenic activity of either anthracycline monosaccharides or their aglycones; however, it dramatically increased the mutagenic activity of aclavinone: correspondence between positive responses in Ames tests and the SOS chromotest was found. Apparently, the mutagenic activity of the substances studied in bacterial cells was mediated by inducing the SOS-repair process. If the compound contained the amino glycoside moiety, functional and structural precursors of the SOS response were formed via intercalation of the reagents into the DNA duplex; if the substance did not contain this moiety, the precursors were formed via ionic interaction.

[Distribution and acute toxicity of a new morpholinoanthracycline, MX2, in normal rat brain after intra-arterial injection].

Intra-arterial infusion chemotherapy has been applied for the treatment of malignant brain tumors to increase the distribution of the drug into the tumor. MX2, a new morpholinoanthracycline, is a lipophilic compound, and has a strong antineoplastic effect against human and rat glioma cells. In this report, the acute toxicity and distribution of MX2 after intracarotid injection were studied using female Wistar rats weighing 150 g. To test the acute toxicity, various doses ranging 1.5 to 6 mg/kg was administered. All rats died within 4 days when received more than 3 mg/kg of intra-arterial or intravenous MX2. No rats died if the dose was reduced to less than 2 mg/kg. For the purpose to examine distribution in the brain, rats which received 2 mg/kg of intra-carotid MX2 were killed 5 to 120 min. after injection. The level of MX2 in the ipsilateral brain tissue reached to the maximum 5 min. after injection, and then rapidly decreased. The maximum concentration of MX2 in the ipsilateral brain was 25-fold higher than that in the contralateral brain, and 20-fold higher than that after intravenous injection of the same dose. The AUC (area under the curve) in the ipsilateral brain after intra-carotid injection was 8.0-fold higher than that in the contralateral brain, and 7.3-fold higher than that after intravenous injection of the same dose. These results indicate that intra-carotid administration can increase the distribution of MX2 in the normal brain.

[Late effects of the hematotoxic action of antineoplastic antibiotics of the anthracycline group]. / Otdalennye éffekty gematotoksicheskogo deistviia protivoopukholevykh antibiotikov gruppy antratsikinov.

The morphological and functional states of hemopoiesis at late periods (up to 6 months) after using daunorubicin, carminomycin and doxorubicin, antitumor antibiotics of the anthracycline group in doses of 1/10 LD50 for 10 days were studied on 764 noninbred rats and 240 BALB/c mice. On various compensatory-functional models of hemopoiesis strain there was shown persisting inhibition of hematopoietic tissue functional activity and limited reserve reactions of granulocyto- and erythropoiesis 3 and to a lesser extent 6 months after the cytostatic action.

[Study of toxicity and antineoplastic activity of 14-substituted derivatives of rubomycin and carminomycin]. / Izuchenie toksichnosti i protivoopukholevoi aktivnosti 14-zameshchennykh proizvodnykh rubomitsina i karminomitsina.

Toxicity and antitumor activity of five derivatives of rubomycin and carminomycin were studied in animals. The derivatives were prepared by modification of the methyl C-14 group. These were the following: 14-chlorrubomycin, 14-chlorcarminomycin, 14-salicyloyloxyrubomycin, 14-salicyloyloxycarminomycin and 14-quinaldinoyloxyrubomycin. The chemotherapeutic study revealed that, in their activity, all the compounds were inferior to the starting antibiotics. Unlike the other derivatives, 14-chlorcarminomycin induced a significant inhibition of leukemia P-388 development (the average lifespan of the mice amounted to 165 per cent as compared to the control). However, in the magnitude of its effect, the derivative was inferior to carminomycin.

[The cytotoxicity of mevalonate, lovastatin and carminomycin with respect to MOLT-4 human malignant T-lymphoblasts in vitro]. / Tsitotoksichnost' mevalonata, lovastatina i karminomitsina v otnoshenii chelovecheskikh zlokachestvennykh T-limfoblastov MOLT-4 in vitro.

It was shown in vitro that high concentrations of lovastatin, a competitive inhibitor of hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase inhibited human malignant cells MOLT-4. The activity of lovastatin in doses of 50-250 microM was dose-dependent. Addition of mevalonate in a concentration of 3 mM to the growth medium completely prevented the cytotoxic effect of 100 microM of lovastatin. At the same time, exogenous mevalonate did not decrease the cytotoxicity of the anthracycline antibiotic carminomycin. Moreover, in a high concentration (7 mM) mevalonate slowly but significantly inhibited the growth of the malignant target cells and the effect was added to the cytotoxic effect of carminomycin low concentrations (0.08 to 0.175 microgram/ml). The results and the literature data suggested that combination of mevalonate, HMG-CoA reductase inhibitors and anthracyclines could be useful in tumor chemotherapy. The suggestion needs further investigation.

[Experience with using carminomycin in oncological clinical practice]. / Opyt klinicheskogo primeneniia karminomitsina v onkologicheskoi praktike.

Carminomycin is an original antitumor antibiotic from the anthracycline group isolated at the Institute of New Antibiotics (USSR) in 1973. Pharmacological investigation of carminomycin revealed its satisfactory absorption from the gastrointestinal tract which proved to be a distinguishing property of the antibiotic as compared to other anthracyclines such as adriamycin and rubomycin. The clinical trials of carminomycin showed that it was mainly active against soft tissue sarcoma and breast cancer, lymphosarcoma, neuroblastoma, Wilms' tumor and Ewing's sarcoma in children, as well as acute leukemia. Various regimens for the antibiotic administration were applied: short-term, single and long-term. Suppression of hemopoiesis was considered as a limiting toxic effect. By the data available carminomycin had lower cardiotoxicity as compared with rubomycin and adriamycin. Development of oral carminomycin is believed promising.

[Thiol-dependent protective systems in alimentary prevention of the toxic effect of carminomycin]. / Tiolzavisimye zashchitnye sistemy pri alimentarnoi profilaktike toksicheskogo deistviia karminomitsina.

The state of the thiol-dependent systems i.e. concentration of the SH-groups, activity of glutathione reductase and glutathione-S-transferase, carminomycin antitumor and toxic effects was studied under conditions of tumor growth and carminomycin therapy with the use of prophylactic rations (PR) aimed at stimulating the cell thiol-dependent and antioxidant systems for decreasing the drug toxic action. It was shown that addition of sulfur-containing amino acids, selenium and vitamin E to the ration of healthy and tumor-bearing rats (Walker carcinosarcoma 256) induced a decrease in the level of the SH-groups in the liver just likely promoting efficient extrahepatic usage of glutathione. After administration of carminomycin a long with the PR use, the liver showed the thiol-preserving capacity evidenced by a decrease or complete elimination of the above effect of the ration. The use of PR resulted in a marked increase in the glutathione-S-transferase activity in cytosol and to a lesser extent in the liver microsomes. A regulating effect of the PR on the activity of glutathione reductase was observed: its inhibition in the healthy animals and stimulation after carminomycin administration in the heart of the healthy animals and the liver of the tumor-bearing animals.

[The structural bases of the cardiotoxic action of the anti-tumor antibiotic carminomycin]. / Strukturnye osnovy kardiotoksicheskogo deistviia protivoopukholevogo antibniotika karminomitsina.

The authors substantiate morphological and structural-functional basis of the cardiotoxic effect of the antitumor anthracycline antibiotic carminomycin after its single intraperitoneal administration in maximum tolerable doses. Results indicate that the cause of development of cardiac failure after administration of carminomycin to experimental animals in the development of an alternative and plastic cardiac failure prevalence of type I.

[The morphological aspects of the protective action of enterosorbent K(2)9 during the use of the antitumor anthracycline antibiotic carminomycin]. / Morfologicheskie aspekty protektornogo deistviia énterosorbenta K(2)9 pri primenenii protivoopukholevogo antratsiklinovogo antibiotika karminomitsina.

The authors substantiate morphologically the protector effect of K(2)9 enterosorbent during its parallel use with the antitumour anthracyclin antibiotic carminomycin. The agent was administered intraperitoneally in animals at the maximum tolerable dose. Use of the K(2)9 enterosorbent reduces the cardiotoxic effect of carminomycin.

[The influence on tumor growth and the function of the thiol-dependent systems of the liver of excess cooking fat and vitamin E in the diet. The effects of carminomycin]. / Vliianie na opukholevyi rost i sostoianie tiolzavisimykh sistem pecheni izbytka kulinarnogo zhira i vitamina E v ratsione. Effekty karminomitsina.

A study was made of the influence of excessive culinary fat in the diet containing 30% of trans-isomers and tocopherol on tumor growth, parameters of antitumor and toxic action of carminomycin, and the state of thiol-dependent defensive systems of the liver. The data obtained have evidenced a negative influence of the experimental ration on the survival of the tumor-carriers and on the condition of the normal animals. Activation of the glutathion S-transferase system attended by the exhaustion of the thiol pool in the liver was recorded. Carminomycin toxic action was not modified by the experimental diet.

[Dependence of the toxicity of the antineoplastic antibiotics rubomycin and carminomycin, on the age and sex of white mice and rats]. / Zavisimost' toksichnosti protivoopukholevykh antibiotikov rubomitsina i karminomitsina ot vozrasta i poly belykh myshei i krys

Karminomycin was more toxic with respect to 2-6 week mice than to adult animals when administered both intravenously or orally. 5-6 week rats were more stable than adult animals to the effect of karminomycin administered intravenously or orally. Significant species sensitivity to karminomycin was noted. When administered intravenously karminomycin administered intravenously was 2 times more toxic as compared to the oral use in the experiments with adult mice and 23 times more toxic in the experiments with adult rats. LD10 and LD50 of rubomycin administerean in adult animals. LD50 of karminomycin and rubomycin administered intravenously to adult female mice was somewhat lower than that for adult male mice.

[Acute toxicity of the N-acyl derivatives of carminomycin and rubomycin]. / Izuchenie ostroi toksichnosti nekotorykh N-atsil'nykh proizvodnykh karminomitsina i rubomitsina.

Synthesis of 2 new N-acyl derivatives of carminomycin and rubomycin (N-L-leucylcarminomycin and N-sarcolysylrubomycin) is described. Acute toxicity of the new and 4 known N-acyl derivatives: N-acetylcarminomycin, N,L-alanylcarminomycin, N-D-phenylalanylcarminomycin and N-D-phenylalanylrubomycin was studied on albino mice. It was shown that the N-acyl derivatives of carminomycin and rubomycin had lower acute toxicity than the initial drugs. When added to blood serum in vitro N-D-phenylalanylcarminomycin and N-D-phenylalanylrubomycin induced precipitation. The carminomycin derivatives containing the residues of L-leucine and L-alanine were less toxic than the initial antibiotic, still they had a markedly pronounced retarded toxicity.

[Preliminary results of a cooperative clinical study of the new antitumor antibiotic, carminomycin]. / Predvaritel'nye rezul'taty kooperirovannogo klinicheskogo izucheniia novogo protivoopukholevogo antibiotika karminomitsina

The clinical trials of karminomycin, a new Soviet antitumor antibiotic in treatment of different malignant tumors showed that the drug had a pronounced antitumor activity against the soft tissue sarcomas of various histogenesis, lympho- and reticulosarcoma, acute leukemia and some other neoplasms.