Biodistribution analysis of cisplatin in liposomal form in animals with cisplatin-resistant and cisplatin-sensitive carcinoma

AIM

To analyze the relation between pharmacokinetics of cisplatin in liposomal form and antitumor efficacy toward cisplatin-resistant and cisplatin-sensitive variants of Guerin carcinoma.

METHODS

Concentration of platinum was measured by atomic absorption spectrophotometry (C115M1 "Selmi", Ukraine). Elimination constant was calculated based on the dynamics of cisplatin concentration in time period between 1 h to 24 h using nonlinear regression analysis. Area under curve (AUC24) was calculated by the trapezium method.

RESULTS

It was shown that for liposomal form of cisplatin (LCp) AUC24 in tumor practically didn't depend on the level of the tumor sensitivity, while in animals with the resistant variant (CpRGC), AUC24 for free cisplatin (FCp) decreased by 70% less (p < 0.001) as compared to the sensitive tumor strain (CpSGC). Significant decrease of elimination constant of LCp compared to FCp in blood serum of rats bearing either CpRGC or CpSGC tumors favors cisplatin accumulation in tumor tissues with low vascularization level. The dynamics of cisplatin concentration in CpRGC variant was characterized by 90% higher level in 24 h after administration of LCp as compared to FCp (p < 0.05). This fact may explain increased antitumor efficacy of LCp compared to FCp toward CpRGC variant. In the study of kidney function, AUC24 index for LCp was by 68.6% (p < 0.01) and 50.7% (p < 0.05) lower than AUC24 index for FCp in rats with CpRGC and CpSGC variants, respectively. No significant differences have been found in biodistribution of cisplatin in both pharmaceutical forms in liver and lung in CpRGC- or CpSGC-bearing rats.

CONCLUSION

The results suggest that cisplatin in liposomal form possesses higher specificity of antitumor action than free cisplatin.

The use of nanoferromagnetics to increase the cytotoxic effect of antitumor drugs

AIM

To investigate the influence of ferromagnetic nanoparticles on antitumor effect of doxorubicin and mitochondria oxidative phosphorylation.

METHODS

The study was carried out on the mice-hybrids (C57Bl/6xDBA/2) with intraperitoneally (i/p) transplantated Ehrlich ascitic carcinoma. Single i/p injection of doxorubicin (Dox), stabilized ferromagnetic nanoparticles (Fe3O4; 20-40 nm; FM) or their combination were performed 7 days after tumor transplantation. The cytotoxic effect of agents, morphology and cell cycle of tumor cells were studied 24, 48 and 72 h after Dox administration.

RESULTS

The investigations showed that ferromagnetic nanoparticles increased the cytotoxic effect of doxorubicin on Ehrlich ascsmall i, Ukrainiantic carcinoma mainly 48 h after agents' administration. The largest number of apoptotic cells was observed in group of animals in which doxorubicin was administered before ferromagnetic nanoparticles. Moreover, the ferromagnetic nanoparticles at concentration 1.45 microg Fe/ml and, particularly, 7.25 microg Fe/ml decreased mitochondria oxygen consumption in phosphorylation state that may negatively influence their living capability.

CONCLUSIONS

Obtained data point out the perspective of use of certain sized FM nanoparticles to increase the cytotoixc effect of antitumor drugs.

Olivomycin induces tumor cell apoptosis and suppresses p53-induced transcription

Olivomycin (DNA-binding antibiotic) in nanomolar concentrations induces apoptosis of human tumor cells and inhibits p53-dependent transcription of the reporter gene (basal and induced by antitumor drugs). Olivomycin aglycon induces no cytotoxicity and does not block transcription.

[Ultrastructural organization of carcinoma Lewis (3LL) cells during cisplatin resistance formation]

The electron-microscopic analysis of the morphological status of 3LL (Lewis) carcinoma tumour cells in the process of cisplatin resistant phenotype formation has been performed. It was shown that selection of tumour cells forming cell clones characterized by more complicated nuclear and cytoplasm organization took place. The tumour cells had the diffused nuclear chromatin; nuclear envelope had the numerous pores with expanded diaphragms. The prominent nucleoli consisted of the active centres surrounded by considerable areas of the condensed nucleolar chromatin. Cell cytoplasm contained the well-developed Goldgi complex and the numerous well-structured myelinoid formations in the form of dense-wrapped concentric membrane structures. The obtained data can morphologically confirm the hypothesis of Gately D.P. and Howel S.B., 1993, thain the process of resistant phenotype formation the tumour cells can create the cellular mechanisms to remove the drug from the cell and to correct the damages of the cellular nucleus and cytoplasm.

Total proteolytic activity and levels of the main proteinase inhibitors in blood plasma of mice bearing Lewis lung carcinoma upon development of resistance to cisplatin

The aim of the study was to evaluate the total proteolytic activity (TPA) and the content of alpha-1-proteinase inhibitor (alpha1PI) and alpha-2-macroblobulin (alpha2M) in the blood plasma of mice with Lewis lung carcinoma (LLC) upon the development of resistance to cisplatin.

METHODS

Experimental LLC model with different sensitivity to cisplatin was obtained by sequential subcutaneous transplantation of LLC cells from cisplatin-treated animals. TPA, alpha1PI and alpha2M levels were evaluated by standard biochemical methods.

RESULTS

It has been shown that the development of LLC resistance to cisplatin is accompanied by the increase of TPA activity and the level of the main proteinase inhibitor - alpha1PI. Despite the high level of alpha1PI in the resistant variant of LLC compared to parental tumor, the increase of TPA/alpha1PI ratio indicated the deficiency of that inhibitor in the blood of mice bearing cisplatin-resistant tumors, that promotes metastasis. The growth of both resistant to cisplatin LLC and sensitive variant was accompanied with the reduction of the alpha2M concentration.

CONCLUSIONS

Upon the development of resistance to cisplatin in vivo the shift in the balance between proteinases and their inhibitors toward activation of TPA simultaneously with the increased metastasis is taking place.

The role of expression of the components of proteome in the formation of molecular profile of human ovarian carcinoma A2780 cells sensitive and resistant to cisplatin

AIM

To study the expression of proteins that characterize drug resistance, proliferation and apoptosis of human ovarian carcinoma cells.

METHODS

The study was carried out on human ovarian carcinoma A2780 cells and on the A2780/DDP8 subline resistant to cisplatin. Expression of the surface and intracellular antigens (p53, Bcl-2, CD95, antigen of proliferating cells, metallothioneins, drug resistance proteins (P-glycoprotein (P-gp), glutathione-S-transferase), molecules of adhesion (E-cadherin, alpha- and beta-catenins) was studied by immunocytochemical method.

RESULTS

It has been shown that the formation of the resistance to cisplatin in A2780/DDP8 cells is accompanied by the increase of expression of glutathione-S-transferase and Bcl-2, by the decrease of expression of CD95-antigene and proliferation potential of the cells, by appearance of EGF receptors and elevation of expression level of E-cadherin, alpha- and beta-catenins, proving the enhancement of adhesive properties of tumor cells.

CONCLUSION

Antiapoptotic program seems to be the leading mechanism of the development of the resistance to cisplatin in A2780/DDP8 cells and is realized via high expression of Bcl-2. During the development of drug resistance of A2780/DDP cells, the program of glutathione detoxification is functionally replacing the decrease of the content of metallothioneins.

Age-related effects of methionine-enriched diet on plasma homocysteine concentration and methylation of hepatic DNA in rats

In the present study we determined the age-related effect of methionine-enriched diet, a model of hyperhomocysteinemia, on the level of plasma homocysteine and hepatic global DNA methylation in rats. Feeding methionine diet to middle-aged rats for only 14 days resulted in a significant increase in plasma homocysteine level and DNA hypomethylation. In contrast, feeding the methionine-containing diet for 2 weeks to juvenile or post-pubertal animals did not alter the level of plasma homocysteine or hepatic DNA methylation. Supplementation of the methionine-enriched diet with vitamins B6, B12 and folic acid prevented both hepatic DNA hypomethylation and an increase of plasma homocysteine concentration in the middle-aged rats. These findings indicate that the elevated level of plasma homocysteine may be indicative of much broader and deeper alterations in intracellular methylation dysfunction, and suggest that dietary enrichment with B-vitamins is essential for the metabolism of homocysteine, especially in adult animals.

The SEIRA spectroscopy data of nucleic acids and phospholipids from sensitive- and drug-resistant rat tumours

It is known that tumour progression towards drug resistance is one of the main factors resulting in the failure of cancer treatment. As tumour progression is based on the genetic instability, the study of the structure of nucleic acid from tumour cells is of great importance both for basic knowledge and for biomedical application. We applied surface enhanced infrared absorption spectroscopy (SEIRA) of nucleic acids on gold substrate and essentially increased the sensitivity of IR spectroscopy. We observed numerous changes in infrared spectra of DNA from sensitive and resistant cells that reflect drastic changes in molecular structure of DNA from tumour cells. The DNA from resistant cancer cells could be characterised as rigid structure, the structure of DNA from sensitive cancer strain seems to be flexible and after application of anticancer drugs drastically changes and approaches to the structure of helix forms. The molecular structure of lipids from resistant and sensitive cancers after application of anti-tumour drugs is also modified. Thus, we observed a disordering in the lipid chain packing from resistant cells after application of cisplatin and, in some cases, formation of phospholipid-Pt complex.

[Use of WOBE-MUGOS E for prevention and correction of experimental doxorubicin side-effects]

Examined in treating rats with Guerin's carcinoma with doxorubicin was the possibility that the polyenzymic drug preparation wobe-mugos E had hepatoprotective, cardioprotective and myeloprotective effects. In intramuscular administration wobe-mugos E has not been found to stimulate the tumour growth, it exhibited a manifest hepatoprotective and myeloprotective actions with respect to adverse reactions of doxorubicin but failed to diminish cardiotoxicity of the latter. The protective effect of the above polyenzymic drug was of a dose-dependent character.

[Lyposomal form of doxorubicin hydrochloride lypodox in the treatment of lymphogranulomatosis and non-Hodgkin's lymphomas]

The article focuses on the possibility of our employing the drug preparation lypodox, a lyposomal form of doxorubicini hydrochloridum, of the Byolek firm, in treating of Hodgkin's disease and non-Hodgkin's lymphomas. A comparative analysis was performed of efficacy and ill effects of lyposomal and free forms of doxorubicini hydrochloridum. It has been shown that by clinical effectiveness the drug preparation lypodox, doxorubicini hydrochloridum in a lyposomal form, is superior to doxorubicini hydrochloridum in a free form in resistant and aggressive forms of Hodgkin's disease and non-Hodgkin's lymphomas. Side reactions developing in the wake of lypodox administration do not threaten the life and health of patients; these do not preclude us from employing the drug in a clinical setting.

[Influence of tumor drug resistance phenotype on the dynamics of cisplatin-induced changes of rat peripheral lymphocyte chromatin structure in Guerin's carcinoma]

The correlation between the tumor drug sensitivity and the degree of lymphocyte interphase nuclei chromatin damages induced by cisplatin in rats was found using sensitive and resistant to cisplatin variants of Guerin's carcinoma. Increased optical density of lymphocyte chromatin in first minutes after cisplatin injection both in rats without Guerin's carcinoma and with sensitive to cisplatin variants of this tumor was observed. Lymphocyte chromatin structure remains unchanged in rats with cisplatin resistant carcinoma. Normal blood cells are suppose to change their sensitiveness to cisplatin under the humoral influence of the growing tumor in according with its phenotype.

Study of acute toxicity of Ukrain in rats after intravenous injection

The acute toxicity of i.v. Ukrain injection in rats was studied. The interrelation between toxicity (death of animals) and dosage was determined by nonlinear regression method. White blood count (WBC) in peripheral blood, weight of animals, and weight of major organs were determined in animals during all stages of investigation. Morphological studies of toxic changes in 40 different organs of rats were performed on macro- and microscopic levels.

Comparative in vitro study of the effects of the new antitumor drug Ukrain and several cytostatic agents on the thiol groups in the tissue of Guerin carcinoma and its resistance to cisplatin variant

A comparative in vitro study between the effects of Ukrain (a new synthetic thiophosphoric acid derivative of great celandine alkaloids) and alkylating antitumor drugs cyclophosphamid and cisplatin on total thiol content in Guerin carcinoma, Guerin/cis-DDP carcinoma, and in animal livers was carried out. It is shown that Ukrain action on thiol groups in Guerin carcinoma tissue does not differ from that of cyclophospamid and cisplatin to both of which Guerin carcinoma is very sensitive. Once tumor resistance to cisplatin has developed, cisplatin does not react with tumor thiol groups and cyclophosphamid reactions with tumor thiol groups decrease. Reactions of Ukrain with thiol groups of cisplatin resistant tumors increase. This indirectly indicates the increase of tumor sensitivity to this drug. Therefore, the cytotoxicity of Ukrain is similar to that of known antitumor drugs and can probably overcome the cisplatin resistance of the tumor.

[Thiol group content in blood serum and in tumor tissue of rats with intact and radioresistant variants of Guerin carcinoma]

Interrelation between the formation of the secondary acquired radioresistance of Guerin carcinoma cells and dynamics of content of thiol groups in the tumour tissue and blood serum of rats have been studies. It is established that the tumour tissue and normal tissues (blood serum) of rats with Guerin's carcinoma respond to the fractional radiation action and to repeated courses of radiation therapy by the reactive increase of the number of free non-protein thiol groups and by the decrease of the content of protein thiols. The use of local superhigh-frequency-hypothermia in the pattern of treatment of the Guerin carcinoma strain resistant to irradiation is accompanied by the increase of the reaction capacity of non-protein thiol groups of the tumour tissue. At the same time the level of general thiol groups in the blood serum decreases while their reactivity increases.

Different growth patterns of a cancer cell population as a function of its starting growth characteristics: analysis by mathematical modelling

The growth kinetics of a cancer cell population as a function of the total number of cells and the proportion of proliferating and resting cells at the beginning of the growth has been analysed by a mathematical model. The model takes into account the processes of cell division, death and transition from proliferation to rest and backwards. It is shown that a single cell population growing under the same environmental conditions has an extremely broad spectrum of growth patterns. The whole multiplicity of possible growth patterns has been determined by the inherent cellular growth characteristics of the population, while the growth pattern actually realized of the variety of growth curves depends on the total number of cells and the proportion of proliferating and resting cells at the initial moment of growth. The model is shown to provide a good prediction of experimentally measured kinetics of regrowth of tumour cells subcultured after various times of the growth in unfed cultures, and the kinetics of tumour cell growth after severe hypoxia. The role of cell transitions between proliferating and resting stages in the problem of growth control is discussed.

[The structural bases of the cardiotoxic action of the anti-tumor antibiotic carminomycin]

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]

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.

[Nonspecific oxidase activity in the liver of rats undergoing chemotherapy with cis-dichlorodiammineplatinum]

A combined administration of cis-dichlorodiaminoplatinum (DDP) and phenobarbital increases the activity of nonspecific oxidases, decreases the toxic effect of DDP especially its nephrotoxic action, but does not decrease the antiblastic action of DDP in rats. On the basis of experimental data the optimum regime of DDP repeated administrations is suggested.