Comparative Culturing of 3T3 Swiss J2 Mouse Embryo Fibroblasts on Modified Chitosan Matrices.

Comparative culturing of mouse embryo fibroblasts on chitosan matrices and culture plastic was carried out. During the first 2 h of culturing (lag phase), cell adhesion to chitosan and chitosan-gelatin matrices was 20-30% higher than adhesion to culture plastic (control). During the stationary phase, 80% cells adhered to chitosan matrices (vs. 60% in the control). Cell culturing on chitosan matrices was carried out without medium replacement with fresh portions. The cells remained viable within 5 days of culturing. Cell death phase was observed on day 6 of culturing on chitosan matrices: cell adhesion dropped to 50%. Culturing on culture plastic was carried out with daily medium replacement with a fresh portion. Cell death phase (50% decrease in the number of adherent cell) under these condition was observed on day 5. It seems that the observed effect was a result of contact interactions of cell integrins and chitosan ligands, modulation of transmembrane signal, eventually modifying the expression of cell genes. This effect can be required in regenerative medicine for production of primary cell culture.

[Synthesis and properties of 5-fluorouracil derivatives].

A series of N-acyl derivatives of 5-fluorouracil (5-FU) bearing residues of palmitic, p-myristoylaminobenzoic, p-oleoylaminobenzoic, and 1-adamantanecarbonic acids was synthesized. Relative rates of hydrolysis of derivatives mentioned under physiological conditions, at pH 7.2 and 37 degrees C, have shown that stability of these compounds increases with reducing of spatial accessibility of amide group at N1 in 5-FU. These substances incorporate easily into lipid bilayer; their liposomal preparations showed substantial cytostatic activity on HBL (human breast lymphoma) cells and are of interest as potential antitumor preparations. Also, a fluorescent analog, 1-[8-(3-perylenyl)octanoyl]-5-fluorouracil, destined for studies of the 5-FU derivatives behavior in cells and tissues was prepared.

[1,10-phenantroline europium complexes: their inclusion in liposomes and cytotoxicity].

For a series of 1,10-phenantroline tris-beta-diketonate europium complexes (EuC), cytotoxic activity on the HBL-100 human breast carcinoma cells was determined. Liposomal preparation of the most active EuC, V12, was also tested for cytotoxicity. Testing of this preparation in vivo on starting lethal murine model of T cell leukemic lymphoma ASF-LL showed that the inclusion of V12 in liposomes did not increase its antitumour activity in a local mode of administration.

[The influence of carbohydrate ligands on the cytotoxicity of liposomes bearing a methotrexate-diglyceride conjugate in human acute leukemia cell cultures].

The efficiency of the chemotherapeutic agent methotrexate (MTX) in tumor cells is limited by the frequent development of the drug resistance of tumor cells. We had previously shown in vitro using human acute leukemia cells with various sensitivity to MTX (T-lymphoblastic CCRF-CEM line and resistant CEM/MTX subline) that MTX incorporation into liposomes as a lipophilic prodrug, diglyceride conjugate (MTX-DG), allows for the overcoming of cell resistance due to the impaired active transmembrane transport. In this work, we have studied the profile of binding with carbohydrates of the cell lines mentioned using carbohydrate fluorescent probes (poly(acryl amide) conjugates). Lipophilic conjugates of tetrasaccharide SiaLe(x), 6'-HSO3LacNAc, and also inactive pentaol for incorporation into liposomes, have been synthesized. The cytotoxicity of MTX-DG liposomes equipped with the SiaLe(x) ligand toward the sensitive CCRF-CEM cell culture was demonstrated to be 3.5 times higher than that of MTX-DG liposomes bearing the control inactive pentaol. The activity of MTX liposomes bearing 6'-HSO3LacNAc toward resistant CEM/MTX was 1.6-fold increased. The use of carbohydrate ligands as molecular addresses for drug-carrying liposomes as a potential method of treating heterogeneous tumor tissue is discussed.

[Liposomal formulation of a methotrexate diglyceride conjugate: activity in methotrexate-resistant leukemia cultured cells].

We have recently synthesized a lipid conjugate of the anticancer agent methotrexate (MTX-DG) and showed that the conjugate is quantitatively included in the lipid bilayer of liposomes prepared by a standard extrusion technique from an 8 : 1 : 1 (mol) egg phosphatidylcholine-yeast phosphatidylinositol-MTX-DG mixture. Both the size of liposomes (126 +/- 30 nm) and the MTX-DG concentration (4.4 mM) are relevant for systemic injections in mammals. The liposomal formulation of MTX-DG was shown to overcome the resistance of tumor cells in vitro to methotrexate: the cytotoxic activities (IC50) of MTX in cultures of the human T-lymphoblastic leukemia cell line CEM-CCRF and the MTX-resistant subline CEM/MTX were 0.075 +/- 0.005 and 16.4 +/- 4.9 microM, respectively, while, in the case of liposomes loaded with MTX-DG, the IC50 values were much closer: 0.77 +/- 0.06 and 3.8 +/- 1.9 microM.

Expression of type IV collagen by Lewis pulmonary carcinoma cells.

Study of the expression of type IV collagen by Lewis pulmonary carcinoma cells (PLMG-T, PLMG-M1, PLMG-M2) showed that these cells produce type IV collagen. The expression of type IV collagen in PLMG-T and PLMG-M2 cells approximately 2-fold surpassed that in PLMG-M1 cells. The number of active cells (synthesizing type IV collagen) in PLMG-M1 culture was 1.6 and 2.2 times lower than in PLMG-M2 and PLMG-T cultures, respectively. It was found that cell culture medium modulated expression of type IV collagen and this effect was mediated via cell receptors.

Phenotypic characteristics of lewis lung carcinoma cells.

We studied adhesive properties and physiological activity in vivo of cells from Lewis lung carcinoma and its metastases. These cells differed in tumorogenic activity and metastatic potential in the syngeneic system. In vivo non-metastasizing cells are characterized by a lower content of surface lectins to tetrasaccharides SiaLex [Neu5Aca2-3Galb1-4(Fuca1-3) GlcNAcb] and SiaLea [Neu5Aca2-3Galb1-3(Fuca1-4)GlcNAcb] and trisaccharide HSO3Lex [HSO32-3Galb1-4(Fuca1-3)GlcNAcb] compared to cells forming metastases in the syngeneic system. Metastatic cells with low tumorogenic activity weakly expressed lectins to disaccharide ligands 6-SiaLac [Neu5Aca2-6Galb1-4Glc], 6-HSO3LacNAc, and A-di [GalNAca 1-3Galb] and trisaccharides H-type 1 [Fuca1-2Galb1-3GlcNAc and Lex [Fuca1-3(Galb 1-4)GlcNAc] compared to cells that initiated tumor formation in the syngeneic system (similarly to transplanted tumors). We hypothesized that cell receptors to these carbohydrate determinates are involved in the development and growth of primary tumors, while lectins to SiaLex, SiaLea, and HSO3Lex play a role in the progress of tumor process and metastasizing.

[Transportation of cytotoxic liposomes to malignant cells using a carbohydrate determinant]. / Transportirovka tsitotoksicheskikh liposom k zlokachestvennym kletkam s pomoshch'iu uglevodnykh determinant.

A method of the synthesis of lipophilic glycoconjugates (vectors) on the basis of polyethyleneglycol-containing detergent was proposed. It has been shown by flow cytofluorometry that fluorescent labeled liposomes equipped with beta-galactosyl conjugate are bound human leukosis HL-60 cells more effectively than liposomes embedded with the beta-glucosyl conjugate or vector-free liposomes. A new lipid derivative of antitumor drug rubomycin (daunorubicin), N-(rac-1,2-dioleoylglycero-3-oxalyl)rubomycin (RubDG) has been synthesized. Liposomes loaded with RubDG and equipped with galactosyl vector showed higher cytotoxic activity in vitro against HL-60 cells than analogous unvectored liposomes or liposomes bearing glucosyl conjugate.

Antiproliferative activity of ceramides isolated from normal human ovary and ovarian tumor.

Ceramides modulate cell growth, differentiation and apoptosis. We have previously demonstrated that human epithelial ovarian tumors contain dihydroceramides that are absent from normal ovary. Dihydroceramides differ in their biological effects from ceramides; therefore antiproliferative activity of ceramides isolated from normal human ovary and ovarian tumors was studied. Ceramides (3 microM) of normal ovary are more potent inhibitors of [3H]thymidine incorporation into human ovarian carcinoma cells (CaOv) than ceramides of ovarian tumors. Effects of various pools of tumor ceramides were similar regardless of significant differences in the contents of sphingenine and sphinganine. It is suggested that antiproliferative activity of ceramides depends not only on the sphingoid base structure but also on the fatty acid structure.

[The marine bacterium Alteromonas piscicida--a producer of enzymes with thrombolytic action]. / Morskaia bakteriia Alteromonas piscicida--produtsent fermentov tromboliticheskogo deistviia.

The ability of marine bacteria A. piscicida to produce exoproteases that were able to lyse human blood clots has been studied. Optimal conditions for biosynthesis of these enzymes have been found. The enzyme has been partially purified. In concentration of 1 mg/ml it has activity corresponding to that of 500 micrograms/l plasmine and 100 micrograms/ml trypsine. The enzyme activity was completely inhibited after incubation in human blood plasma.

[Biological activity of a polar lipid of Clostridium butyricum spores]. / Biologicheskaia aktivnost' poliarnogo lipida spor Clostridium butyricum.

A fraction of polar lipids was isolated from spores of the anaerobic bacterium Clostridium butyricum 35/11 exerting a noticeable radioprotective effect. The main biological activity of spore extracts was associated with this fraction. The fraction of polar lipids inhibited autolysis of the bacterial cell walls. The fraction was found to contain a phenolic glycolipid and a peptide component. The bacteriostatic and radiotherapeutic properties of the fraction are presumed to be due to its membranotropic activity.

[Superoxide dismutase in Clostridium butyricum spores]. / Superoksiddismutaza c sporakh Clostridium butyricum.

Superoxide dismutase was found for the first time in the spores of the anaerobic bacterium Clostridium butyricum. The prosthetic group of the enzyme was shown to contain iron. The enzyme was demonstrated to be highly thermostable.