[Experimental evaluation of synergism of cisplatin with L-lysine-alpha-oxidase].

Synergism effects of cisplatin and L-lysine-alpha-oxidase (LO), while sequential (no interval) administration of drugs depends on the tumor model and duration of treatment. Synergism is identified at intraperitoneal daily (during 3 days) administration of cisplatin to experimental animals in single doses of 1.5 or 3.0 mg/kg and intravenously 5-fold after 48 h administration of LO and also administered intravenously in cumulative doses of 300-600 E / kg discretely, the first dose--doubled. Synergism of cisplatin and LO is showed by significant (p < 0.05) therapeutic gain against cisplatin at such indicators as increased survival of mice with P388 tumor and increased inhibition of primary tumor melanoma B16.

[Cross-immunogenicity of various bacterial L-asparaginases].

AIM: Evaluate immune response in mice against various L-asparaginases and determine their cross-immunogenicity. MATERIALS AND METHODS: The studies were carried out in C57Bl(6j) line mice. Immunogenicity of L-asparaginases was studied: Escherichia coli type II (recombinant) (Medak, Germany) (EcA); Erwinia carotovora type II (ErA); Yersinia pseudotuberculosis type II (YpA); Rhodospirillum rubrum type I (RrA); Wollinella succinogenes type II (WsA). Immune response against the administered antigens was determined in EIA. RESULTS: Y. pseudotuberculosis L-asparaginase was the most immunogenic, E. coli--the least immunogenic. E. carotovora, R. rubrum, W. succinogenes asparaginases displayed intermediate immunogenicity. The results of cross-immunogenicity evaluation have established, that blood sera of mice, that had received YpA, showed cross-immunogenicity against all the other L-asparaginase preparations except E. carotovora. During immunization with E. coli L-asparaginase the developed antibodies also bound preparation from E. carotovora. Sera from mice immunized with W. succinogenes, E. carotovora and R. rubrum L-asparaginases had cross-reaction only with EcA and did not react with other preparations. CONCLUSION: Cross-immunogenicity of the studied L-asparaginases was determined. A sequence of administration of the studied preparation is proposed that allows to minimize L-asparaginase neutralization by cross-reacting antibodies.

[Recombinant intracellular Rhodospirillum rubrum L-asparaginase with low L-glutaminase activity and antiproliferative effect].

The recombinant producer of Rhodospirillum rubrum L-asparaginase (RrA) was received and purification procedure of RrA was developed. It was shown that RrA has following biochemical and catalytic characteristics: K(m) for L-asn 0.22 MM, pH optimum 9.2; temperature optimum 54 degrees C; pI = 5.1 +/- 0.3; L-gln activity seems to be low-to-negligible. K562, DU145 and MDA-MB-231 cellular lines displayed significant sensitivity towards the enzyme (IC50 = 1.80; 9.19 and 34.62 ME/ml, respectively. In comparison with L-asparaginases from E. coli II type (EcA) and Erwinia carotovora (EwA) cytotoxicity of RrA seems to be higher than EwA, but lower than EcA. 10-fold i.p. RrA administration (4000 ME/kg per day) in L5178y bearing mice showed T/C = 172%. The received results show that RrA belongs to I type cellular L-asparaginases with low L-gln activity and the high antiproliferative effect.

[Physicochemical properties and antiproliferative activity of recombinant Yersinia pseudotuberculosis L-asparaginase].

The physicochemical, catalytic, and antiproliferative activity of a recombinant L-asparaginase from Yersinia pseudotuberculosis (YpA) have been studied. The following results were obtained: the K(M) value for L-asparagine is 17 +/- 0.9 microM, the optimal temperature is 60 degrees C, pH is 8.0, pI is 5.4 +/- 0.3, the L-glutaminase activity is no more than 5-6% of the L-asparaginase activity, and the antiproliferative activity on the Fisher L5178y lymphadenosis cell line comprised T/C = 136% (p < 0.001) at a 15% recovery rate. The described characteristic allows one to regard YpA as an antitumor enzyme with biological features similar to the L-asparaginase of E. coli.

[Differential medium for selection of bacterial L-asparaginase producer strains].

A specific, fast, and easy method for revelation of active plate producers of L-asparaginase using differential medium on the basis of LB or M9 with 1.5% agar was developed. Each 100 ml of LB or M9 medium additionally contained 6-7 ml ofglycerol, 4 g of L-asparagine, 0.2 g of CaCO3, and diagnostic components: 3 ml of 0.2 M CuSO4 x 5H2O and 2.5 ml of 0.1 M K3Fe(CN)6, pH 7.6-7.8. The results were counted 12-20 or 24-48 h after strain growth at 37 degrees C in corresponding mediums. Red color of colonies and colored zone around them showed the ability of the strain under study to destroy asparaginic complexes. The recommended method allows revealing bacterial strains producing L-asparaginase with specific activity of not less than 0.1-3.0 MU/mg of protein.

[Hematological toxicity of some combined chemotherapy schemes involving aranoza].

Hematological toxicity of four combined chemotherapy schemes--TAr, TPAr, EPAr, and IPAr--involving aranose (Ar), cisplatin (P), etoposide (E), irinotecan (I), and topotecan (T) in therapeutic regimes has been studied on healthy mice in comparison to the treatment with Ar in a high therapeutic dose. It is established that Ar alone induces early leucopenia, mostly as a result of lymphocytopenia followed by the absolute and relative neutrophilia; the TAr treatment leads to a moderate neutropenia; whereas the ternary combinations cause a moderate lymphocytopenia. A relatively high hematological toxicity among the ternary combinations was observed for TPAr. The total number of erythrocytes and thrombocytes in the peripheral blood of mice under the action of Ar and all combinations remains on the control level. The inclusion of Ar into the indicated schemes neither modifies the spectrum of hematological toxicity nor increases its level. The observed changes in the peripheral blood were reversible and were not accompanied by any impairment in the state of mice. The obtained results allow the combinations involving P, E, I, T, and Ar to be considered as promising for further investigation.

[Pre-clinical study of combined aranosa, cisplatin and irinotecan in the treatment of experimental lung cancer].

Data are presented on evaluation of use of combinations of aranosa (Ar), irinotecan (I) and cisplatin (C) in treatment of Lewis lung carcinoma. The drugs were administered i.p. simultaneously, in single doses: irinotecan 20-100 mg/kg, single dose, cisplatin 2.5 3.0 mg/kg and aranosa 100-200 mg/kg, three doses. High synergism (IP, PAr, IPAr) and sufficient tolerance were reported. Efficiency of IPAr regimen was significantly higher while hematotoxity prognosis - comparable to those of IP.