[An expedient synthesis of fluorescent labeled ceramide-1-phosphate analogues].

A synthesis for fluorescent analogs of ceramide-1-phosphate bearing 9-anthrylvinyl or 4,4-difluoro-3a,4a- diaza-s-indacene-8-yl (Me4-BODIPY) fluorophore at o-position of fatty acid residue was carried out. The key stage of the synthesis is hydrolysis of corresponding sphingomyelins catalyzed by phospholipase D from Streptomyces chromofuscus; the enzymatic yield has been raised to 50-70% by appliance of organic solvent in the incubation medium.

[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.

[New 4,4-difluoro-3alpha,4alpha-diaza-s-indacene (BODIPY) labeled sphingolipids for membrane studies].

The synthesis of a series of new fluorescence labeled sphingolipids containing 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3alpha,4alpha-diaza-s-indacene-8-yl (Me4-BODIPY-8) group at omega-position of a fatty acyl residue is described. The obtained probes were used in studies of biological and model membrane systems.

[Synthesis and characteristics of new fluorescent probes based on cardiolipin].

New fluorescent lipid probes, cardiolipin derivatives AV12-CL and B7-CL, bearing the residues of 12-(9-anthryl)-11E-dodecenoic and 7-(4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacen-8-yl)heptanoic acid, respectively, have been synthesized by acylation of 1-lysocardiolipin, which had been obtained from bovine heart cardiolipin by enzymatic hydrolysis with bacterial lipase. The resulting probes are intended for the study of protein-anionic phospholipid interactions.

[Identification of a new carbohydrate-binding site of influenza virus].

It has recently been shown that the influenza virus can specifically bind the residue of a nonsialylated sulfated oligosaccharide Gal(6SO(3)H)beta1-4GlcNAcbeta (6'SLacNAc). To identify by photoaffinity labeling the virion component that binds 6'SLacNAc, we synthesized a carbohydrate probe containing a (125)I labeled diazocyclopentadien-2-yl carbonyl group as an aglycone. According to the electrophoretic data, the labeled areas corresponded to a large hemagglutinin subunit, a nucleocapsid protein, and neuraminidase (NA). Probing in the presence of an excess of 6'SLacNAcbeta-OCH(2)CH(2)NHAc glycoside resulted in redistribution of the labeling intensity, with the maximum inhibition being observed for NA. The data obtained indicate that NA is a viral 6'SLacNAc-binding protein.

[Depth-dependent investigation of the apolar zone of lipid membranes using a series of fluorescent probes, Me4-BODIPY-8-labeled phosphatidylcholines].

A series of lipid probes, phosphatidylcholines labeled with Me4-BODIPY-8 (4,4-difluoro-1,3,5,7- tetramethyl-4-bora-3a,4a-diaza-s-indacen-8-yl) fluorophore attached to the end of an acyl residue at different distances from the polar head, were used as depth-dependent probes for the apolar zone of model membrane systems, large unilamellar vesicles (LUVs). Data on the anisotropy of probe fluorescence demonstrated different mobility profiles for the fluorophore microenvironment in LUVs of different composition at various temperatures, which indicates a high sensitivity of these probes as tools for studying membrane systems. An interesting anomaly was observed for LUVs from dimiristoylphosphatidylcholine (DMPC) or from a DMPC-cholesterol mixture: the anisotropy of the fluorophore located near the bilayer center is larger than that of the fluorophore located further from the center; i.e., the mobility of the microenvironment is lower in the first case. This anomaly is supposed to result from the penetration of the unlabeled long chain of the probes into the opposite bilayer leaflet. Such a possibility should be taken into account in constructing fluorescent probes and interpreting the results.

[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.

[Synthesis of a lipid derivative of the antitumor agent methotrexate]. / Sintez lipidnogo proizvodnogo protivoopukholevogo preparata metotreksata.

A lipophilic methotrexate prodrug capable of incorporation into membranes of carrier liposomes was synthesized. The conjugate consists of a lipophilic rac-1,2-dioleoylglycerol anchor connected to methotrexate through beta(Ala)-N-carbonylmethylene linker, which should be located in the polar region of the lipid bilayer. The ester bond between the hydrophilic linker and the antitumor agent can be hydrolyzed by intracellular esterases. The liposomal formulation of the prodrug exhibited a cytotoxic activity in vitro. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.

[Fluorescent properties of 9-anthracenecarboxamides]. / Fluorestsentnye svoistva amidov 9-antratsenkarbonovoi kisloty.

A number of new 9-anthracenecarboxamides are synthesized in order to create new fluorescent probes for studying biological systems. The parameters of their fluorescence in organic solvents of various polarities are investigated, and possible mechanisms of internal quenching of fluorescence of these compounds are discussed. One of the compounds, 4-ethoxycarbonylphenylamide of 9-anthracenecarboxylic acid, is shown to be a promising basis for the development of a new fluorescent probe. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.

[Synthesis of photoreactive neoglycolipid probes--instruments for studying membrane lectins]. / Sintez fotoreaktivnykh neoglikolipidnykh zondov--instrumentov dlia izucheniia membrannykh lektinov.

A method for the synthesis of photoaffinity neoglycolipid probes with a highly efficient carbene-generating diazocyclopentadien-2-ylcarbonyl (Dcp) label, which can be radioiodinated under standard oxidation conditions, was developed. The probes are intended for incorporation into the lipid bilayer. They are lipophilic glycoconjugates on the basis of an amphiphilic aglycone built up from a diacylglycerol and a polyethylene glycol spacer (with a polymerization degree of 9-16) bearing the Dcp label at the terminal unit. The location of the label in the aglycone provides the possibility of one-step preparation of a wide range of probes using various carbohydrate synthons. We have synthesized photoaffinity neoglycoconjugates containing the oligosaccharides: sialyl LewisX tetrasaccharide and A trisaccharide, which is specific to some tumor cells. A probe containing an inactive pentaol (aminodeoxyglucitol) was also synthesized to detect nonspecific binding. The Dcp label is bound to the probe molecule by ester bond; its lability under alkaline conditions facilitates the analysis of cross-linked products after photoaffinity labeling. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.

[Synthesis and properties of fluorescently-labelled triglyceride, derivative of the antineoplastic agent sarcolysin]. / Sintez i svoistva fluorestsentnomechenogo triglitserida, proizvodnogo proteivoopukholevogo agenta sarkolizina.

A new fluorescent probe, a 3-perylenoyl derivative of the lipophilized antitumor drug merphalan (sarcolysine), was synthesized. The probe is suitable for studying intracellular traffic and metabolism of merphalan and its derivatives. The perylenoyl fluorescence is partially quenched by the merphalan chromophore, which broadens the probe potentialities. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.

[Synthesis and characteristics of fluorescent BODIPY-labeled gangliosides]. / Sintez i svoistva fluorestsentnykh BODIPY-mechenykh gangliozidov.

A series of new fluorescent-labeled gangliosides bearing the residues of acids labeled by 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) in the polar or/and apolar moiety were synthesized. These are ganglioside GM1 labeled with the residue of 4,4-difluoro-4-bora-3a,4a-diaza-5,7-dimethyl-s-indacenyl-3-propanoic BODIPY-FL-propanoic) and -indacenyl-5-pentanoic (BODIPY-FL-pentanoic) acid in the oligosaccharide moiety of the molecule, and ganglioside GD1a labeled with two residues of BODIPY-FL-pentanoic acid in the oligosaccharide moiety and also with the residue of BODIPY-FL-pentanoic acid and the residue of 4,4-difluoro-4-bora-3a,4a-diaza-5-octyl-s-indacenyl-5-pentanoic acid in the ceramide part of the molecule. Some spectral characteristics and the behavior in the model membrane systems of the synthesized probes were studied. In their emission spectra, the BODIPY-labeled gangliosides included into phosphatidylcholine liposomes at high concentrations (> 1 mol %) exhibit a long-wavelength maximum (at approximately 630 nm) in addition to the usual maximum (at 510-515 nm).

[New fluorescent bichromophoric probes for studying mechanisms of donor-donor energy migration (DDEM)]. / Novye fluorestsentnye bikhromofornye zondy dlia issledovaniia mekhanizmov donor-donornoi migratsii énergii (DDEM).

Three fluorescent probes were synthesized for studying the excitation energy migration between two identical fluorophores. Each probe has two identical fluorescent groups (dansyl, 7-nitrobenz-2-oxa-1,3-diazole-4-yl, or fluoresceinyl) linked by the rigid bis-(8-aminooctyl)amide of 4,4'-biphenyldicarbonic acid or flexible dotriacontanedioic acid spacer, which enables the intramolecular energy migration through the distance of 3.2-3.5 nm.

[Unusual fluorescent properties of N-9-anthroyl derivatives of aromatic amines]. / Neobychnye fluorestsentnye svoistva N-9-antroil'nykh proizvodnykh aromaticheskikh aminov.

9-Anthroyl derivatives of some aromatic amines exhibit unusual fluorescence characteristics. In solvents of low and medium polarity (hexane, chloroform, DMF, and tert-butanol), their emission maxima are shifted to longer wavelengths as compared to the spectra recorded in polar solvents (ethanol and methanol); the red shift is accompanied by an increase in the fluorescence quantum yield. Possible reasons of such an anomalous spectral shift are discussed.

[The synthesis of new photoaffinity probes on the basis of ganglioside GM1]. / Sintez novykh fotoreaktivnykh zondov na osnove gangliozida GM1.

New photoaffine probes, photoreactive derivatives of ganglioside GM1 bearing a carbene-generating diazocyclopentadien-2-ylcarbonyl group at various distances from the carbohydrate moiety in their molecules, were synthesized.

[Synthesis and properties of fluorescent labeled detergents analogues of glycocholic acid]. / Sintez i svoistva fluorestsentnomechenykh detergentov, analogov glikokholevoi kisloty.

For studying membrane processes with participation of detergents, fluorescent analogues of glycocholic acid containing p-hydroxybenzyl, 7-nitrobenz-2-oxa-1,3-diazol-4-yl, or fluorescein-5-thiocarbamoyl fluorophore in the glycyl moiety attached to glycocholic acid were synthesized. The fluorophores are in the probes near their carboxyl groups and, in membrane systems, should therefore be situated on the interface and be sensitive to phase transitions. The critical micelle concentrations were determined for the analogues and found to be close to those of cholate and glycocholate in the case of the first two compounds. We presume that the behavior of the probes in membrane systems will mimic the behavior of the bile acid salts.

[Fluorescent lipid probes: properties and application]. / Fluorestsentnye lipidnye zondy: svoistva i primenenie.

This review is devoted to fluorescent lipid probes: the characteristics of their fluorophores; the main methods of their synthesis; and the potentialities, scope, and limitations of their use in studies of biological systems (cells, membranes and their models, enzymes of lipid metabolism, etc.). Particular attention is paid to the lipid specificity of the probes, i.e., the correspondence of their physicochemical characteristics and behavior in biological systems to those of natural lipids.

[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.

[Lipid derivatives of sarcolysin, methotrexate and rubomycin]. / Lipidnye proizvodnye sarkolizina, metotreksata i rubomitsina]

To change the pharmacokinetic properties of the known antitumor agents sarcolysine, rubomycin, and methotrexate, their lipid derivatives were synthesized with the residues of rac-1,2-dioleoylglycerol and heptadecyl alcohol. An ether lipid analog, 3-sarcolysyl 2-methyl-1-octadecyl-sn-glycerol, with the lipid moiety being itself an antineoplastic agent was also obtained.