Pathomorphological picture of the testes of mice administered antitumor antibiotics and their comparative evaluation

A single administration of the LD50 of bruneomycin, carminomycin, rubomycin or olivomycin and the use of the antibiotics for 10 days in a dose 2 times higher than the therapeutic one and amounting to 10 per cent of the LD50 induced dystrophic and destructive changes in the sexual glands of mice. The changes in the testis were more pronounced after the single use of the antibiotics. Recovery processes were observed in the testis beginning from the middle of the third week after the use of carminomycin and rubomycin and from the end of the second week after the use of olivomycin. Bruneomycin was an exception: the pronounced destructive changes in the sexual glands after its single or repeated use persisted within the observation period.     

Myeloinhibitory effect of the action of some antitumor antibiotics and its comparative assessment]

General toxic and myeloinhibitory effects of some antitumor antibiotics, such as rubomycin, olivomycin, bruneomycin and karminomycin administered intraperitoneally in a single LD50 to mice were studied. It was found that the general toxicity of bruneomycin and karminomycin was almost the same and 5 to 8 times higher than that of rubomycin and olivomycin. The use of the above antibiotics resulted in definite shifts in the blood systems of healthy mice. The most significant suppression of hemopoesis accompanied by a pronounced depression of the number of the myelocariocytes was observed after the use of olivomycin. The effect of karminomycin was characterized by suppression of erythro-, myelo- and lymphopoesis and depression of the number of the granulocytes and lymphocytes of the blood. Bruneomycin and rubomycin had a short-time myeloinhibitory effect. The erythroid cords of the bone marrow proved to be most sensitive to the inhibitory effect of the antibiotics. However, inhibition of the erythropoesis accompanied by deep reticulocytopenia did not induce the respective depression of the erythrocyte number. The lymphoid cords was in the 2nd place by its sensitivity to the antibiotics and the myeloid and megocariocytal cords were in the 3rd and the 4th places respectively. Complete reduction of hemopoesis in the animals was observed by the 10th day of the drugs use.     

Effect of carminomycin on the energy metabolism of the liver in rats]

The effect of carminomycin on the liver energetic metabolism was studied experimentally on rats in dynamics after its intraperitoneal administration in a single LD50 and the therapeutic doses for a treatment course. It was found that changes in the rat liver tissues on the part of the energetic metabolism occurred irrespective of the antibiotic dose and the administration multiplicity. Mainly they were of reversible nature: the balance of consumption and resynthesis of the phosphate macroergs was impaired, the glycolytic processes increased, shifts in the activity of the enzymes of the pentose phosphate pathway of oxydation were observed. The level of the above changes was more pronounced when carminomycin was administered in LD50. The adrenal system played an important role in the mechanism of the shifts noted.     

Development of bruneomycin and rubomycin resistance in mouse lymphadenosis tumor cells and Staphyloccus when these preparations are used separately or together

Two sublines of mouse lymphadenosis (L-5178) resistant to bruneomycin and rubomycin used alone, as well as a subline with induced resistance to the combination of these drugs were employed in the study. The studies showd that in separate use of rubomycin and bruneomycin the tumor cell resistance to the respective drug was evident at the 10th passage. After 30 passages neither bruneomycin nor rubomycin produced reliable inhibition of the tumor growth in the respective subline of lyphadenosis. When the antibiotics were used in combination, no significant decrease in sensitivity of the tumor cells to either of the drugs or their combination was observed. The experiment with Staph. aureus also showed that the rate of the resistance increase to the drug combination was lower than that to the drugs used alone. Therefore, it was shown that the combined use of bruneomycin and rubomycin provided a means for preventing to a significant extent of development of the resistance in lymphadenosis tumor cells and Staph. aureus. This may be considered as an indication for clinical trials of the above combination.     

Semisynthetic derivatives of daunorubicin and carminomycin: inhibition of DNA synthesis after intravenous administration to mice

Inhibition of DNA synthesis in the liver, kidneys, spleen and heart of mice after intravenous administration of 0.1 and 0.3 LD50 of semisynthetic derivatives of rubomycin (daunorubicin) and carminomycin was studied. The level of DNA synthesis inhibition was estimated by a decrease in incorporation of (methyl-3H) thymidine. Under the action of 13-trebutoxycarbonyl hydrazone and 14-salicyloiloxy derivatives of rubomycin and carminomycin maximum inhibition of DNA synthesis was reached later while its recovery started earlier as compared to the initial antibiotics.     

Effect of rubomycin and carminomycin on antibody formation during the immunization of mice with various antigens

The maximum immunodepressive effect of rubomycin and carminomycin was observed when the antibiotics were administered intravenously 24 hours after the immunization. The immune response induced by the sheep erythrocytes or the lipopolysaccharide was equally inhibited by rubomycin. Carminomycin in a dose of 0.5 mg/kg (0.1 of the LD50) to a larger extent inhibited the immune response stimulated by the lipopolysaccharide. Dependence of the immunodepressive effect of the antibiotics on their dose was found when the drugs were administered intravenously or orally.     

Protein-nitrogen metabolism in the liver of rats intraperitoneally administered carminomycin]

It was found in the experiments with rats that in response to carminomycin administration in a single LD50 and the therapeutic doses during the treatment course the intracellular fond of the amino acids in the liver tissue increased, the autolytic processes activated, the activity of the transamination enzymes, histidine and ammonia lyases increased. The level of the residual nitrogen increased mainly at the expense of increased ammonia production and urea levels. These changes were more pronounced when the antibiotic was administered in LD50. Independent of the administration multiplicity and the antibiotic dosage they were of reversible nature and mainly disappeared by the end of the observation.     

Suppression of DNA synthesis in mice by the anthracycline antibiotics daunorubicin, carminomycin and doxorubicin

Inhibition of DNA synthesis by rubomycin (daunorubicin), carminomycin and doxorubicin in the spleen, liver, kidneys and heart was studied on mice. The antibiotics were administered intravenously in a dose of 0.3 LD50. The inhibition level was estimated by incorporation of 3H-thymidine. The time courses of DNA synthesis inhibition by daunorubicin, carminomycin and doxorubicin markedly differed, whereas the patterns of their inhibition curves for all the organs were close. The maximum inhibition of DNA synthesis by carminomycin was observed in 6 hours. After that period it gradually restored. Doxorubicin induced the maximum inhibition of DNA synthesis in 24-48 hours after its administration. Daunorubicin induced two maxima in inhibition of DNA synthesis i. e. in 6 and 48 hours. Definite correlation between the levels of DNA synthesis inhibition by the antibiotics and their toxic action was shown.     

Effect of the anthracycline group antibiotics, mitomycin C and bruneomycin, on the transduction of drug resistance in staphylococci]

The effect of various concentrations of antitumor antibiotics, such as carminomycin, rubomycin, adriamycin, mitomycin C and bruneomycin on transduction of erythromycin resistance from the donor strain 8325 P II/de of Staph, aureus to the recipient strain 8325-I in different transduction systems was studied. It was shown that the above antibiotics inhibited the transduction in the systems with constant presence of the drugs. Preliminary treatment of the recipient cells with the drugs in the subbacteriostatic doses did not decrease the transfer frequency. The preliminary treatment of the donor cells resulted in an increase in the phase titer and the transfer frequency in the "preliminary-treated donor + recipient" system.     

Role of antibiotics in the ecology of actinomycetes]

The organisms producing ristomycin, rifamycin, lincomycin, tobramycin, rubomycin carminomycin, olivomycin, bleomycin and actinomycin D were practically not sensitive to their own antibiotics in the concentrations close to those produced during the biosynthetic process. At the same time other actinomycetous species close to the above organisms were suppressed to a significant extent by their antibiotics in the same concentrations. The experimental data indicated that the antibiotics had a protective effect on the organisms producing them and played a significant role in ecology of the actinomycetes.     

Toxicity and cumulative properties of carminomycin, rubomycin and adriamycin at different times of use]

LD50 of karminomycin, rubomycin and adriamycin were determined after their single administration or 3-, 5-, 10- and 15-fold administration once a day to 540 hybrid male mice F1(C57B1 X CBA). Comparison of the cumulative indices for these antibiotics showed that after injections they were close. After 5 injections the cumulative properties were more pronounced for adriamycin. After 10 or 15 injections the cumulative properties were less pronounced for karminomycin.     

Effect of the diuretic diacarb on the antitumor activity of the antibiotics rubomycin and olivomycin]

Combined use of rubomycin and olivomycin with diacarb in treatment of rats with Pliss lymphosarcoma increased the antiblastomic activity of the antibiotics. The antitumor effect of rubomycin and olivomycin was increased by diacarb in the same degree as that of dipin, a synthetic cytostatic.     

Antiviral action of carminomycin and some of its derivatives]

Carminomycin was shown to inhibit the development of both the DNA-containing variolovaccine virus and the RNA-containing grippe virus in chick embryos. Comparison of the effects of rubomycin, carminomycin, 14-oxy-carminomycin and carminomycin complex with bovine serum albumin in experiments with chick embryos showed that the inhibitory effect of carminomycin and its derivatives on the development of the grippe virus was much higher than that of rubomycin. The carminomycin derivatives proved to be much more active in this respect than the initial antibiotic. Carminomycin and its derivatives had a therapeutic effect on mice with experimental grippe pneumonia also on their oral use.     

New derivatives of carminomycin and rubomycin

For preparing new semisynthetic analogs of anthracycline antibiotics, hydrolysis of 13-dimethylketals of 14-bromrubomycin and 14-brom-arminomycin in solution of diluted hydrochloric acid was studied. It was shown that such hydrolysis yielded 14-chlorrubomycin and 14-chlorcarminomycin. Conditions for separating the mixture of 14-chlor- and 14-bromrubomycins and the mixture of 14-chlor- and 14-bromcarminomycins by HPLC were developed. Interaction of 14-chlorine derivatives of rubomycin and carminomycin with potassium formate in the presence of the crown ether yielded 14-formyloxy derivatives of rubomycin and carminomycin. Interaction of rubomycin and carminomycin with formic acid in the presence of N-oxysuccinimide and dicyclohexylcarbodiimide resulted in formation of N-formyl derivatives of rubomycin and carminomycin.     

Inhibition of synthesis of nucleic acids, proteins and respiration in isolated thymocytes by anthracyclines

The effect of anthracycline antibiotics such as carminomycin, daunomycin (rubomycin) and adriamycin on respiration and synthesis of nucleic acids and protein was studied comparatively. The anthracyclines inhibited the processes. By their efficacy in that respect they could be arranged in the following order: carminomycin greater than rubomycin greater than adriamycin. Thus, 50 per cent inhibition of nucleic acid synthesis in the thymocytes required 0.027, 0.044 and 0,173 mM of carminomycin, rubomycin and adriamycin respectively. Protein synthesis and respiration in the thymocytes were less sensitive to the effect of the anthracyclines than synthesis of nucleic acids. The study results were compared with the literature data on the effect of the compounds on respiration and synthesis of nucleic acids and protein in tumour and bacterial cells.     

Experience with using carminomycin in oncological clinical practice]

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.     

Interaction with DNA of semisynthetic carminomycin and rubomycin derivatives

The apparent binding constants and the effect of semisynthetic derivatives of carminomycin and rubomycin (anthracycline antibiotics) on DNA fusion were studied. The following semisynthetic derivatives were used. 13-dihydrocarminomycin, 14-hydroxycarminomycin, 13-(4-methylpiperazinyl) imine carminomycin, 13-benzoylhydrazone carminomycin (carminazone), 13-tret-butoxycarbonyl hydrazone rubomycin, 13-(4-methylpiperazinyl) imine rubomycin, 14-(1-hydroxyl-2,2,6,6-tetramethylpiperidyl-4)-acetoxyrubomycin (spin-labeled rubomycin). The above derivatives slightly differed from the initial antibiotics by their affinity to DNA. The binding constants of methylpiperazinyl imines was 2-3 times higher than those of the respective antibiotics.     

Development of resistance in Fisher lymphadenosis cells to dipin and bruneomycin when these preparations are used separately and in combination]

It was shown that dipin and bruneomycin resistant tumor cells appeared in mice with transplanted lymphadenosis after 10 passages on single use of the drugs. When the drugs were used in combination, no lymphadenosis cells resistant either to bruneomycin, or to dipin and their combination were found. The combined use of the drugs prevented development of resistance to them in the lymphadenosis cells at least during 10 passages on mice. The data on the possible prevention of the resistance development in the mouse lymphadenosis cells by means of combined use of low doses of dipin and bruneomycin provided an assumption that it is expedient to test the combination in clinics.     

Oxidation of anthracycline antibiotics

The quantum-chemical estimation of the highest occupied molecular orbital energy for the aglycons of carminomycin, rubomycin, adriamycin and aclacinomycin A in the neutral and ionized states was performed with a semiempirical method. It was shown that the aglycon ionization amplified the electron donor properties of the antibiotics. On the basis of the difference in the absorption spectra of the neutral and ionized chromophores their ionization constants were determined spectrophotometrically. For comparison of the electron donor properties of the anthracyclines at the physiological pH value the reaction of their oxidation with potassium ferricyanide accompanied by decoloration of the solutions was studied. On the basis of the quantum-chemical and experimental data it was concluded that the electron donor properties amplified as follows: aclacinomycin A less than adriamycin-rubomycin less than carminomycin. At the same time their acute toxicity increased (a decrease in the LD50). Therefore, the toxicity of the anthracycline antibiotics could be also due to formation of the radicals with high reactivity on the monoelectronic oxidation.     

Blood coagulation system in oncological patients treated with rubomycin, adriamycin and carminomycin]

Systems of blood coagulation in patients treated with antibiotics of the anthracycline group were studied. Rubomycin was used in the treatment of patients with acute leukemia Adriamycin and carminomycin were used in the treatment of patients with solid tumors. The antibiotics affected the process of blood coagulation mainly through their cytostatic effect on thrombocytopoesis. Thrombocytopenia induced deficit of thrombocytal factors participating in the process of blood coagulation which resulted in hypocoagulation and hemorrhagic complications. The plasmic factors did not significantly change during the antibiotic therapy. A tendency to decrease in the levels of prothrombine, fibrinase and fibrinogen was noted which was possible due to an inhibitory effect of the antibiotics on the function of the reticuloendothelial tissue cells or indirectly to suppression of the tumor process. More pronounced changes in the system of blood coagulation of patients treated with rubomycin were probably associated with inferiority of the thrombocytal apparatus of the patients with acute leukemia treated with the antibiotic.