Vol 510, No 1 (2023)

The effect of PARP1 knockout in HEK293 cells on the gene expression of DNA base excision repair (BER) proteins was studied. It was shown that the expression of all differentially expressed genes (DEGs) of BER was reduced by knockout. The expression of the DNA glycosylase gene NEIL1, which is considered to be one of the common “hubs” for binding BER proteins, has changed the most. The expression of genes of auxiliary subunits of DNA polymerases δ and ε is also significantly reduced. The PARP1 gene knockout cell line obtained is an adequate cell model for studying the activity of the BER process in the absence of PARP1 and testing drugs aimed at inhibiting repair processes. It has been found for the first time that knockout of the PARP1 gene results in a significant change in the level of expression of proteins responsible for ribosome biogenesis and the functioning of the proteasome.

The development of CAR-T specific therapy made a revolution in modern oncology. Despite the pronounced therapeutic effects, this novel approach displayed several crucial limitations caused by the complications in pharmacokinetics and pharmacodynamics controls. The presence of the several severe medical complications of CAR-T therapy initiated a set of attempts aimed to regulate their activity in vivo. We propose to apply the barnase-barstar system to control the cytotoxic antitumor activity of CAR-T cells. To menage the regulation targeting effect of the system we propose to use barstar-modified CAR -T cells together with barnase-based molecules. Barnase was fused with designed ankyrin repeat proteins (DARPins) specific to tumor antigens HER2 (human epidermal growth factor receptor 2) The application of the system demonstrates the pronounced regulatory effects of CAR-T targeting.

ABSTRACT Glioblastoma multiforme (GBM) is the most aggressive malignant brain tumor. One of the reasons for the resistance of MGB to treatment is the extreme heterogeneity of the tumor and, in particular, the presence of cancer stem cells (CSCs) in the population of glioblastoma cells. In this work, we investigated the effect of conditions that reduce the proportion of CSCs in the GBM cell population on the levels of long noncoding RNAs (lincROR and MALAT1) involved in the formation of the phenotype of glioblastoma cancer stem cells. We have shown that culturing under conditions that cause a decrease in cell stemness (when fetal calf serum is added to the culture medium) affected the content of these transcripts: in the cells of most of the analyzed lines, a decrease in the level of the positive stemness regulator lincROR and an increase in the content of MALAT1 were noted.

To date, various strategies have been proposed to increase the effIciency of cancer therapy. It is known that the action of DNA repair system can determine the resistance of cancer cells to DNA-damaging chemotherapy and radiotherapy, and one of these ways to increase therapeutic efficiency is the search for inhibitors of enzymes of the DNA repair system. Inhibition of the DNA repair enzyme tyrosyl-DNA phosphodiesterase1 (Tdp1) leads to an increase in the effectiveness of the topoisomerase 1 (Top1) inhibitor, the anticancer drug topotecan. Covalent complexes Top1-DNA, which are normally short-lived and are not a threat to the cell, are stabilized under the influence of topotecan and lead to cell death. Tdp1 eliminates such stabilized complexes and thus weaken the effect of topotecan therapy. We have previously shown that the use of the usnic acid hydrazonothiazole derivative OL9-119 in combination with topotecan increased the antitumor and antimetastatic efficacy of the latter in a mouse model of Lewis lung carcinoma. In this work, it was shown that the combined use of topotecan and Tdp1 inhibitor, the hydrazonothiazole derivative of usnic acid OL9-119, leads to an increase in the DNA-damaging effect of topotecan which is used in the clinic for the treatment of cancer. The study of the proapoptotic effect of the compound OL9-119 showed that the compound itself does not induce apoptosis, but increases the proapoptotic effect of topotecan. The results of the study could be used to improve the effectiveness of anticancer therapy and/or to reduce the therapeutic dose of topotecan and, therefore, the severity of side effects.

The study investigated the effect of GABA in various concentrations and D-GB-115 at a concentration of 10^–10 mol/ml on the behavior of Paramecium caudatum. It has been shown that GABA increases motor activity and changes the movement strategy of these protozoa, and the dose-effect relationship is domed, which can be explained by the presence of two types of GABA receptors in the outer membrane of paramecia: GABA-A and GABA-B. The range of active concentrations of GABA ranges from 10^–6 to 10^–16 mol/ml. The effect of pharmacological agents interacting with the GABA system on the behavior of infusoria: nembutal and D-GB-115.

For the first time, the regularities of the number and species diversity dynamics of wintering waterfowl in 30 cities of Russia over eight years have been analyzed. The total number increased by 35%. The species diversity in total reaches 32 species. Mallards (Anas platyrhynchos) dominate in all 30 cities. According of total characteristics, all cities were divided into seven clusters, significantly differing from each other. The geographical location and climatic characteristics of cities are the main conditions for the existence of both people and birds. The number variability of wintering birds by 93% is determined by the area of the city and the number of its population, and the number of species by 62% is determined by the longitude, the average January temperature of the city and the number of its population (p < 0.001). The number of birds and species correlate with the “age” of wintering place (p < 0.05). If the rate of the urbanization continues, the number and species diversity will continue to grow.

For the first time, different lifetime was established in representatives of three colour morphs (brown, bicolor, black) in 10 populations of the Mole Vole of the Volga region, the Urals and the Trans-Urals. With the longest life span of the species – 5 years, numerically dominant morphs in the population are able to live 1–4 years longer than the accompanying ones. Spearman’s correlation coefficient between the longest life span of morphs and their proportion in the population was R_sp = 0.81. A number of morphofunctional features of colour morphs have been identified. The results obtained have general biological significance, confirming the hypothesis of adaptive polymorphism, and allowing us to evaluate the evolutionary and ecological mechanisms of the formation of selective advantages of morphs (as probable ecomorphs), using them as a natural model of the initial stage of sympatric formation in different parts of the range.

It is established that the rule of G. Hutchinson’s idea of the ratio of body weight and size and foraging organs of similar species is not fully respected when comparing the species of shrews of the genus Sorex. The similarity of the centroid sizes of the mandible of large species S. isodon and S. araneus was revealed. By methods of geometric morphometrics, differences in the shape of the mandible, which is actively used in foraging, have been established between the species. Interspecific differences in mandibular indices reflecting trophic specialization and functional features of mandibles were found. Therefore, shrews can avoid competition even if Hutchinson’s rule is violated, and not so much due to the size, but due to the transformation of the lower jaw, its specialization, methods of capturing prey and changing the diet. Consequently, Hutchinson’s ecological rule is not mandatory, but only one of the conditions for reducing competition between closely related species.

It is known that stresses during the cultivation of agricultural plants reduce yields, and the occurrence of stressful effects leads to the release of allelotoxins by plants into the soil. It has been suggested that this factor can have a noticeable effect on the vegetation of vegetables in greenhouses, and a decrease in the concentration of allelotoxins in greenhouse substrates can improve the vegetation of plants. To verify these assumptions, the allelotoxicity of greenhouse substrates and the content of microorganisms in them under well and poorly vegetating plants of cucumbers, tomatoes and peppers were determined. It was found that there are significantly more allelotoxins and fewer prokaryotes in the substrates under poorly vegetating plants, which confirmed the assumption about the significance of the allelotoxins influence on the cultivation of vegetables in greenhouses. The introduction of humate solutions with a high sorption capacity in relation to allelotoxins into the root zone of plants makes it possible to significantly improve the vegetation of cucumbers and may be a promising direction for increasing vegetable yields in greenhouses.

The expression of RNA-binding proteins and their interaction with the spliced pre-mRNA are the key factors in determining the final isoform profile. Transmembrane protein CD44 is involved in differentiation, invasion, motility, growth and survival of tumor cells, and is also a commonly accepted marker of cancer stem cells and epithelial-mesenchymal transition. However, the functions of the isoforms of this protein differ significantly. In this paper, we developed a method based on the boosted beta regression algorithm for identification of the significant RNA-binding proteins in the splicing process by modeling the isoform ratio. The application of this method to the analysis of CD44 splicing in colorectal cancer cells revealed 20 significant RNA-binding proteins. Many of them were previously shown as EMT regulators, but for the first time presented as potential CD44 splicing factors.