Immunocompetent Mice As a Model for Preclinical Studies of mRNA Vaccine Immunogenicity.

Conducting preclinical studies of mRNA vaccines is complicated by the lack of relevant animal models of the human immune system. Immunocompetent mice are widely used in biomedical research. However, critical differences in the genetics and immune system of mice and humans prevent the study of unique human immune responses in mice. Within the framework of this work, the possibility of modeling the cytotoxic T-cell response to mRNA vaccines encoding the S-protein of the SARS-CoV-2 virus was investigated. High-affinity peptides from S-protein were analyzed for the most frequent allelic variants of human MHC-I, two immunocompetent mouse lines (C57BL/6, BALB/c) and an outbred mouse model of IRC. The results of computer modeling have shown that mouse models can be used in preclinical studies of mRNA vaccines against SARS-CoV-2. Mouse MHC-I is able to present virus peptides that are highly affine for human MHC-I. Moreover, the immunogenicity of some of them has already been confirmed by examining blood samples from patients who have had COVID-19.

Intracellular Gemcitabine Monophosphate Levels Predict Chemotherapy Efficacy in Gemcitabine-Treated Patients with Bladder Cancer.

Gemcitabine monophosphate (dFdCMP), one of the intracellular forms of phosphorylated gemcitabine, determines its antitumor activity. A pharmaco-molecular model for determining relative gemcitabine monophosphate level based on the assessment of the activity of ENT1 and ENT2 channels as well as dCK and CDA enzymes in tumor tissue was developed. Relative gemcitabine monophosphate level is a more relevant predictive factor of gemcitabine resistance of bladder cancer as compared with the expression of individual markers related to dFdCMP formation.

Riboflavin photoactivation by upconversion nanoparticles for cancer treatment.

Riboflavin (Rf) is a vitamin and endogenous photosensitizer capable to generate reactive oxygen species (ROS) under UV-blue irradiation and kill cancer cells, which are characterized by the enhanced uptake of Rf. We confirmed its phototoxicity on human breast adenocarcinoma cells SK-BR-3 preincubated with 30-µM Rf and irradiated with ultraviolet light, and proved that such Rf concentrations (60 µM) are attainable in vivo in tumour site by systemic intravascular injection. In order to extend the Rf photosensitization depth in cancer tissue to 6 mm in depth, we purpose-designed core/shell upconversion nanoparticles (UCNPs, NaYF4:Yb3+:Tm3+/NaYF4) capable to convert 2% of the deeply-penetrating excitation at 975 nm to ultraviolet-blue power. This power was expended to photosensitise Rf and kill SK-BR-3 cells preincubated with UCNPs and Rf, where the UCNP-Rf energy transfer was photon-mediated with ~14% Förster process contribution. SK-BR-3 xenograft regression in mice was observed for 50 days, following the Rf-UCNPs peritumoural injection and near-infrared light photodynamic treatment of the lesions.

[CLINICAL CASE OF DIROFILARIASIS.]

The paper describes a case of the rare localization of a pregnant Dirofilaria female in a man's genitalia. Patient T born in 1973 was infected in the Krasnoyarsk Territory presumably in the summer of 2012. A migratory mass appeared under the skin of the chest at the beginning of 2016. A dense mass was located beneath the skin in the penis by early April. Histological specimens from the removed tumor, entered the specialized Clinical Diagnostic Laboratory for parasitic diseases. The specimens exhibited transverse and oblique sections of Dirofilaria spp. The body cavity contained nematodes - multiple microfilariae. However, routine studies and PCR could not reveal the microfilariae in the blood.

Antiangiogenic Activity of Alofanib, an Allosteric Inhibitor of Fibroblast Growth Factor Receptor 2.

Alofanib is a potential allosteric inhibitor of FGFR2 used in oncology. The inhibitor blocks the extracellular part of the receptor and prevents its binding with the ligand. Alofanib suppressed proliferation of endothelial cells, their migration activity, and ability to form vessellike structures in vitro and significantly decreased the number of microvessels in Matrigel implant and in ovarian cancer (SKOV-3) xenograft in vivo. The results indicate that Alofanib can inhibit angiogenesis.

[Recombinant fragment of pigment epithelium-derived factor (44-77) prevents pathological corneal neovascularization].

Pigment epithelium-derived factor (PEDF), a 50 kDa secreted glycoprotein, is among the most potent endogenous inhibitors of angiogenesis. PEDF-derived fragment (44-77) possesses antiangiogenic properties of the full-sized protein and is a potential drug candidate for the treatment of ocular neovascular diseases. In this study we propose an efficient scalable biotechnological method for the production of PEDF (44-77) as part of a fusion protein with SspDnaB intein. The fusion protein was obtained in bacterial E. coli cells in the form of inclusion bodies, solubilized and subjected to autocatalytic cleavage with the release of PEDF (44-77) (yield, 77%). The target peptide was separated from the intein using tangential ultrafiltration. The final purification of PEDF (44-77) was performed by reversed-phase HPLC. The yield of the target peptide (purity, 99%) was 65 mg per 1 liter of culture. Antiangiogenic activity of the obtained peptide was studied in vitro using murine endothelial cells SVEC-4-10. PEDF (44-77) suppressed proliferation of endothelial cells by 53% and inhibited endothelial cell tube formation at the concentration of 1 nM. The ability of the recombinant PEDF (44-77) to block initial stages of angiogenesis was demonstrated using the model of rabbit corneal neovascularization.

[pAkt expression in cervical intraepithelial neoplasia (CIN) and in microinvasive cervical cancer].

The study objective was an immunohistochemical evaluation of pAkt expression in 81 CIN and microinvasive cervical cancer tissue samples and 10 samples of relatively "normal" cervical epithelium of HPV-infected women. PAkt expression showed significant up-regulation in CIN2, CIN3 and microinvasive cancer in compare to CIN1 and "normal" epithelium. The rate of pAkt- positive cells increased progressively by cervical neoplasia grade advancement reaching 7 +/- 5% in CIN2, 15 +/- 13% in CIN3 and 17 +/- 15% in microinvasive cancer. The rate of pAkt-positive cases in general was 1,7-fold higher in CIN3 (41%) than in CIN2 (24%). pAkt expression in conjunction with other markers may be used in immunohistochemical studies for individual CIN outcome prognosis and prospectively in immunocytochemical tests for CIN grade diagnostics improvement before using invasive methods. To elaborate multicomponent system of markers with their indexation there is a need for further investigations with greater number of cases.

[Ki-67 expression, thymidine phosphorylase and PTEN in intraepithelial cervical carcinoma].

Expression of Ki-67, thymidine phosphorylase (TP) and PTEN were assessed in various grades of cervical intraepithelial neoplasia (CIN) in order to evaluate their potentials of predicting the gravity of possible damage to the epithelium as well as pro- or regression of CIN. Ki-67 and TP levels were shown to correlate directly with CIN grade. It was suggested that a small number of cases of Ki-67 and TP expression absence (15%), exclusively in CIN3 samples, be due to imminent progression to invasive cancer. Both separately and in combination, Ki-67 and TP expression indices should be regarded as having a potential as markers for cervical carcinoma diagnosis, grade and clinical course.

[Use of an enzyme immunoassay test system with cystic Echinococcus antigen to diagnose echinococcosis alveolaris (multilocularis) (alveococcosis)].

Twenty-three serum samples from 12 patients with Echinococcus alveolaris collected 1 to 12 years after surgery and 1--13 courses of specific therapy were used to evaluate the diagnostic effectiveness of an enzyme immunoassay (EIA) test system with cystic Echinococcus antigen. The findings enable the EIA test system with cystic Echinococcus antigen to be recommended for the diagnosis of Echinococcosis alveolaris and for the monitoring of its treatment results.

[Crohn's disease: genetic aspects].

The paper deals with the topical problem of modern gastroenterology and coloproctology--the influence of genetic factors on the development and course of Crohn's disease (CD). It presents the data of foreign authors and the results of Russia 's first study evaluating the effect of the major polymorphic variants of the NOD2/CARD15 gene predisposing to CD on the risk, course, and other features of CD.

p53 hot-spot mutants increase tumor vascularization via ROS-mediated activation of the HIF1/VEGF-A pathway.

The function of p53 tumor suppressor is often altered in various human tumors predominantly through missense-mutations resulting in accumulation of mutant proteins. We revealed that expression of p53 proteins with amino-acid substitutions at codons 175 (R175H), 248 (R248W), and 273 (R273H), representing the hot-spots of mutations in various human tumors, increased the number of vessels in HCT116 human colon carcinoma xenografts and, as a result, accelerated their growth. Stimulation of tumor angiogenesis was connected with about 2-fold increase in intracellular level of reactive oxygen species (ROS). Antioxidant N-acetyl-l-aspartate (NAC) decreased vessels number in tumors formed by cells with inactivated p53 and inhibited their growth. Effect of ROS on angiogenesis in tumors expressing hot-spot p53 mutants was correlated with their ability to increase a content of HIF1 transcriptional factor responsible for up-regulation of VEGF-A mRNAs.

[Effect of Coriolus hirsutus laccase on atrazine adsorption and desorption by different types of soil ].

Study of adsorption-desorption behavior of herbicide atrazine in soils of different geographical zones in the presence of Coriolus hirsutus laccase was performed. Laccase was shown to significantly increase adsorption coefficient and to facilitate irreversible adsorption of atrazine to soil. Supposably, laccase catalyzes oxidative binding of atrazine to soil.

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 3. Inhibitory effect of SkQ1 on tumor development from p53-deficient cells.

It was proposed that increased level of mitochondrial reactive oxygen species (ROS), mediating execution of the aging program of an organism, could also be critical for neoplastic transformation and tumorigenesis. This proposal was addressed using new mitochondria-targeted antioxidant SkQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) that scavenges ROS in mitochondria at nanomolar concentrations. We found that diet supplementation with SkQ1 (5 nmol/kg per day) suppressed spontaneous development of tumors (predominantly lymphomas) in p53(-/-) mice. The same dose of SkQ1 inhibited the growth of human colon carcinoma HCT116/p53(-/-) xenografts in athymic mice. Growth of tumor xenografts of human HPV-16-associated cervical carcinoma SiHa was affected by SkQ1 only slightly, but survival of tumor-bearing animals was increased. It was also shown that SkQ1 inhibited the tumor cell proliferation, which was demonstrated for HCT116 p53(-/-) and SiHa cells in culture. Moreover, SkQ1 induced differentiation of various tumor cells in vitro. Coordinated SkQ1-initiated changes in cell shape, cytoskeleton organization, and E-cadherin-positive intercellular contacts were observed in epithelial tumor cells. In Ras- and SV40-transformed fibroblasts, SkQ1 was found to initiate reversal of morphological transformation of a malignant type, restoring actin stress fibers and focal adhesion contacts. SkQ1 suppressed angiogenesis in Matrigel implants, indicating that mitochondrial ROS could be important for tumor angiogenesis. This effect, however, was less pronounced in HCT116/p53(-/-) tumor xenografts. We have also shown that SkQ1 and related positively charged antioxidants are substrates of the P-glycoprotein multidrug resistance pump. The lower anti-tumor effect and decreased intracellular accumulation of SkQ1, found in the case of HCT116 xenografts bearing mutant forms of p53, could be related to a higher level of P-glycoprotein. The effects of traditional antioxidant N-acetyl-L-cysteine (NAC) on tumor growth and tumor cell phenotype were similar to the effects of SkQ1 but more than 1,000,000 times higher doses of NAC than those of SkQ1 were required. Extremely high efficiency of SkQ1, related to its accumulation in the mitochondrial membrane, indicates that mitochondrial ROS production is critical for tumorigenesis at least in some animal models.

Effects of prenatal and neonatal cadmium intoxication on the intensity of lipid peroxidation and activity of glutathione system in progeny of albino rats.

Oral treatment of pregnant or lactating rats with Cd(NO3)2 in a dose of 2 mg/kg increased plasma and erythrocyte levels of MDA and reduced glutathione, activities of glutathione-S-transferase, glutathione reductase, and gamma-glutamyl transferase in their 4-month-old progeny. Changes in the function of glutathione system and LPO intensity after cadmium intoxication during the neonatal were less pronounced than after prenatal exposure.

[Characterization of plant phenolic compounds by cyclic voltammetry].

Phenolic acids and flavonoids were characterized by cyclic voltammetry and total antioxidant activity in the reaction with the ABTS cation radical. Anode peak voltages (Eap) and their pH dependences were determined for the studied phenolic acids and flavonoids. The Eap and Trolox equivalent antioxidant capacity (TEAC) values were found to correlate for polyphenols, which react with the ABTS cation radical in two steps. Correlation between the half-wave potential (Ep/2) and TEAC was determined for electrochemically irreversible compounds. Mechanisms of the reaction of phenolics on the electrode involving one- and two-electron oxidation are proposed.

[Development of a novel enzyme-redox-mediator system based on a fungal laccase and ruthenium complexes].

The laccase produced by the fungus Coriolus hirsutus has been coordinatively modified with ruthenium complexes [Ru(phpy)(phen)(MeCN)2]PF6 and Ru(bpy)2CO3 under aerobic and anaerobic conditions. The amount of the complexes per enzyme molecule does not depend on the oxygen concentration, equaling 5 for [Ru(phpy)(phen)(MeCN)2]PF6 and 3 for Ru(bpy)2CO3. The pH dependence of the enzymatic activity, thermostability, and catalytical and electrocatalytical properties of the modified laccase are reported. It has been shown that, during the modification, at least one molecule of the ruthenium compound was coordinated near the T1 active center of the laccase, being directly involved in the catalysis and enhancing its efficiency.

[Laccase of the lignolytic fungus Trametes hirsuta: purification and characterization of the enzyme, and cloning and primary structure of the gene].

The main physicochemical characteristics of the major isoform of the laccase secreted by the fungu, Trametes hirsuta 072 were studied. The enzyme belongs to the group of high redox potential laccases (E(T1) = 790 +/- 5), and it oxidizes with high efficiency various substrates of phenolic nature. The gene of this isoform was cloned, and its nucleotide sequence was determined. The length of the complete gene is 2134 bp. It comprises 11 exons and 10 introns. Analysis of the amino acid sequence of T. hirsuta 072 laccase demonstrated a high homology (to 96.9%) to the other laccases secreted by fungi of the genus Trametes.

Development of differential sensitivity of CaOv ovarian adenocarcinoma cells to antitumor agents under conditions of hypoxia.

We studied the role of VEGF signal pathway in autocrine regulation of tumor cell growth and survival under conditions of hypoxia. Hypoxia-resistant CaOv/H substrain with high level of VEGF-A secretion was obtained by long-term culturing of CaOv ovarian adenocarcinoma cells with CoCl2 (hypoxia inductor). VEGF-A directly participates in autocrine regulation of CaOv cell growth, including the maintenance of cell growth under conditions of hypoxia or cytostatic treatment. On the other hand, CaOv/H cells retain high apoptotic potential and are characterized by high expression of p27Kip1 (cyclin-dependent kinase inhibitor), which attests to possible involvement of this inhibitor into the regulation of apoptotic response of cells under conditions of hypoxia.

[Thymidylate synthase, thymidine phosphorylase and dihydropyrimidine dehydrogenase expression in soft-tissue sarcoma versus capecitabine potential].

Expression of thymidylate synthase (TS), thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) can predict for clinical outcome of fluoropyrimidine-based therapy and there is every likelihood that relevant tumors will respond. High TP expression was observed in 35 (42%) patients with soft-tissue sarcoma. Seven out of 26 (27%) such patients revealed molecular phenotype prognostically favorable for capecitabine therapy. More clinical research is required to assess the efficacy of capecitabine-based therapy.