Vol 43, No 2 (2017)

The article reports the development of a collection of lentiviral vector constructs enabling time-efficient production and testing of different variants of chimeric antigen receptors (CAR). These artificial surface proteins make it possible to redirect the activity of immune cytotoxic T-cells towards cancer cells. Chimeric antigen receptors usually encompass four functional modules, namely, antigen recognition, flexible linker, transmembrane, and signal modules. The use of modules with different properties allows modulating the affinity and specificity of CAR interaction with target antigens, as well as intensity and quality of activation signaling, which determines the cytotoxic properties of CAR T-cells, as well as their proliferation rate and time of persistence in the organism. The proposed vector system make it possible to easily test various combinations of CAR modules while its being open to distribution allows the direct comparison of the results obtained by different scientific groups.

Microvesicles were isolated from blood plasma and total blood of healthy females and breast cancer patients by filtration and ultracentrifugation. According to flow cytometry, different subpopulations of exosomes were represented in blood of healthy donors and cancer patients at different levels with median fluorescence intensity (MFI) values in both groups arranged in the following order: CD24/СD9 > СD9/СD81 > CD9/CD63 = CD24/CD63. Concentration of exosomes in blood plasma of healthy females estimated by nanoparticle tracking analysis (NTA) did not exceed (3.71 ± 1.15) × 10⁷ particles/mL of blood and did not differ from that in plasma of breast cancer patients, which averaged (3.99 ± 1.03) × 10⁷ particles/mL of blood. Concentration of total exosomes in blood (including exosomes from plasma and blood cell surface-bound exosomes) did not depend on the presence/absence of a tumor; the values were (7.66 ± 0.7) × 10⁷ particles/mL of healthy blood and (9.4 ± 1.24) × 10⁷ particles/mL of blood from cancer patients. Comparative analysis of exosomes using 2-D electrophoresis with subsequent analysis of 2-D proteomic maps revealed proteins missing in blood or differentially expressed in healthy females and breast cancer women. The data presented provide the possibility for identification of exosomal proteomic markers and isolation of tumor-specific exosomes, which contributes to the development of breast cancer diagnostics.

A novel series of the DBP(n) fluorescent symmetric dimeric bisbenzimidazoles in which the bisbenzimidazole fragments were attached to an oligomeric linker with the 1,4-piperazine residue in its center were prepared. The DBP(n) molecules were distinguished by the number of methylene groups n (where n = 1, 2, 3, 4) in the linker. The DBP(n) synthesis was based on a condensation of the monomeric bisbenzimidazole (MB) with 1,4-piperazinedialkylcarbonic acids. The ability of the DBP(n) dimeric bisbenzimidazoles to form complexes with the double-stranded DNA was demonstrated by a complex of physicochemical methods, including spectroscopy in the visual UV-area, circular dichroism (CD), and fluorescence. The DBP(1–4) molecules were localized in the DNA minor groove by the CD method with the use of cholesteric liquid-crystalline dispersions (CLCD) of the double-stranded DNA. The DBP(n) dimeric bisbenzimidazoles were easily soluble in water, penetrated through cellular and nuclear membranes, and stained DNA in living cells distinct from the previously synthesized DB(n) series.

Second-generation (G2) polyamidoamine (PAMAM) dendrimers are branched polymers containing 16 surface primary amine groups. Due to their structural properties, these polymers can be used as universal carriers in various drug delivery systems. Amine-terminated PAMAM dendrimers are characterized by a high positive surface charge, leading to effective but nonspecific interactions with negatively charged cell plasmatic membranes. To reduce the nonspecific internalization of PAMAM dendrimers, their primary amine groups are often modified by acetic or succinic anhydrides, polyethylene glycol derivatives and other compounds. In this work, the role of primary amine groups, which are localized on the surface of doxorubicin-conjugated (Dox) dendrimers, was studied with regard to their intracellular distribution and internalization rates using SKOV3 human ovarian adenocarcinoma cells. It was demonstrated that all Dox-labeled G2-derivatives containing different numbers of acetamide groups synthesized in this work show high rates of cellular uptake at 37°С. As expected, the conjugate carrying the maximum number of primary amine groups demonstrated the highest rates of binding and endocytosis. At the same time, the G2-Dox conjugate containing the maximum number of acetamide groups showed colocalization with LAMP2, a marker of lysosomes and late endosomes, as well as the highest level of cytotoxic activity against SKOV3 cells. We conclude that second-generation PAMAM dendrimers are characterized by varied pathways of internalization and intracellular distribution due to the number of primary amine groups on their surface and, as a consequence, a different surface charge.

The antimicrobial activity and cytotoxicity of novel 1,3-bis(alkyl)-6-methyluracil derivatives containing 1,2,3- and 1,2,4-triazolium fragments in alkyl chains have been studied. The compounds have been tested for the antimicrobial activity toward some gram-positive and gram-negative bacteria and fungal cultures. The cytotoxic action has been estimated toward mammalian cells. It has been found that the basic structural factor that affects the antimicrobial activity is the nature of alkyl radicals at triazole fragments.

The synthesis of novel thiazole-based piperidinone oximes and screening of their antioxidant and antimicrobial activity are described. The obtained results revealed that the electronic effects of active substituents at C-4 terminals of phenyl rings on either side of piperidinone skeleton, as well as at 2-hydrazinyl thiazole, played a major role in development of antioxidant and antimicrobial activity. Antioxidant activity seems to be based also on radical dissipating ability of the thiazole ring. The nucleophilic character of sulfur in thiazole and lipophilic nature of piperidinone skeleton substantially influenced the observed antimicrobial activity of thiazole-based piperidinone oximes. Among the synthesized compounds, 2,6-bis(4-hydroxy-3-methoxyphenyl)-1-methylpiperidin-4-one O-(2-(2-(4-hydroxy-3-methoxybenzylidene)hydrazinyl)thiazol-4-yl) oxime exhibited excellent antioxidant activity whereas compound 2,6-bis(4-chloro phenyl)-1-methylpiperidin-4-one O-(2-(2-(4-nitrobenzylidene)hydrazinyl)thiazol-4-yl)oxime emerged as an outstanding antimicrobial agent.

A method of insect juvenile hormone III (JH-III) labeling by thermally activated tritium was developed. Purification of the labeled compound was performed on a TLC silica gel plate using a system of hexane-ethyl acetate 2: 1. The molar radioactivity of [³H]JH-III was 2.2 Ci mmol^–1. It was shown that tritium-labeled juvenile hormone can be used in the radiometric method for quantitative measurement of the activity of specific enzymes that hydrolyze juvenile hormone.

Using directed (substitution T203Y) and subsequent random mutagenesis of the monomeric cyan fluorescent protein mTurquoise2, we obtained a protein with a tryptophan-based chromophore that fluoresces in the green region of the spectrum (excitation maximum 482 nm, emission maximum 519 nm). Fluorescence of the new protein is highly stable in a wide range of pH (pK_a 4.9), more stable than all monomeric green fluorescent proteins with a tyrosine-based chromophore.