Evgeniya Sergeevna Pogodina’s research while affiliated with Ulyanovsk State University and other places

Cancer is a leading cause of death worldwide. A promising modality for cancer treatment is peptide receptor radionuclide therapy. Therapeutic radionuclide is delivered using peptide-based vectors, which can bind to specific receptors on the cancer cell surface. Bombesin receptors are one of the receptors peculiar to many types of cancer, which can be targeted by peptide vectors. Peptides have a number of advantages, but they also have one serious drawback: low stability in the internal environment. To solve the problem, it is possible to the include a therapeutic peptide in the structure of a highly stable knottin peptide. Objective. The aim of the study is to examine the stability of BBN/C1-C2 structure, created on the basis of U5-scytotoxinSth1a knottin and bombesin tropic to bombesin receptor, and the ability of this structure to bind to target receptors on the cancer cell surface. Materials and Methods. BBN/C1-C2 peptide was obtained by solid-phase peptide synthesis. Then, is underwent chromatography purification under analytical chromatography and mass spectrometry control. Stability was studied by analytical chromatography. Competitive inhibition analysis was carried out using a fluorescently labeled GRP peptide with excess BBN/C1-C2 and fluorescently labeled BBN/C1-C2 with GRP bombesin receptor inhibitor. Cancer cell line PC-3 expressing bombesin receptors and normal cell line CHO-K1 not expressing bombesin receptors were used in the work. Results. The conducted studies have shown that hybrid BBN/C1-C2 peptide based on bombesin peptide inserted into the U5-scytotoxinSth1a knottin framework between the first and second cysteine residues has a greater stability compared to the commercial radiopharmaceutical PSMA-617. BBN/C1-C2 peptide is specific to bombesin receptor: it binds to PC-3 cancer cell line with a target bombesin receptor on its surface, and does not bind to the healthy CHO-K1 cell line, without a target receptor. BBN/C1-C2 peptide shows high affinity for the bombesin receptor, since GRP prevents its binding to the PC-3 cell line.

Ischemia contributes to many pathological conditions encountered in clinical practice. Besides, subsequent reperfusion may worsen tissue damage, exacerbating injuries caused by ischemia. Shifts in the balance of calcium and sodium ions play a major role in the development of ischemia-reperfusion injury. Inhibitors of calcium and sodium ion channels located on the membrane surface can help to avoid a sharp disturbance in the ion balance. Although such inhibitors reduce cell death, their mechanisms of action differ. The aim of the study is to conduct a comparative analysis of the mechanisms of action of peptide inhibitors of calcium and sodium channels on ischemia-reperfusion damage to epithelial cells. Materials and Methods. Peptide synthesizer was used for toxin synthesis. Chromatography and mass spectrometry were used for quality control. Analysis of cell death, changes in calcium and sodium ion concentrations, and pH levels were performed using fluorescent dyes and a multimodal reader. Results. It was found that peptide inhibitors of calcium and sodium channels reduce apoptosis and necrosis levels in CHO-K1 culture under simulated ischemia/reperfusion. The calcium channel inhibitor reduces cell death by lowering calcium and sodium ion concentrations and maintaining physiological pH levels throughout the reperfusion phase. The sodium channel inhibitor reduces death by lowering calcium and increasing sodium concentrations, and by maintaining an elevated pH throughout the reperfusion phase. Conclusion. Although both calcium and sodium concentrations as well as their mutual influence play an important role in the development of ischemia-reperfusion injury, inhibition of certain channels has different effects on intracellular processes with the same result, namely reduced cell death.

Background Bombesin (BBN) is a short peptide with a high affinity for receptors that are expressed on the surface of various types of cancer cells. However, a full length BBN molecule has low in vivo stability. Background Bombesin is a short peptide with high affinity for a receptor that is expressed on the surface of various types of cancer cells. However, the full length BBN molecule has low in vivo stability. Objective In our study, we propose the use of peptide toxins, derived from animal and plant toxins, as scaffold molecules to enhance the bioavailability and stability of bombesin. These peptides possess a unique structure known as an inhibitory cystine knot. Objective In our work, as a scaffold molecule to increase the bioavailability and stability of bombesin, we propose the use of peptide toxins that are part of animal and plant poisons and have a special structure - an inhibitory cystine knot. Methods We synthesized structures in which short bombesin was incorporated into various domains of arthropod and plant toxins using solid-phase peptide synthesis. The stability under different conditions was assessed through high-performance liquid chromatography, and binding to cell cultures expressing the bombesin receptor was analyzed. Additionally, toxicity to cell cultures was evaluated using fluorescence microscopy. Results The data obtained demonstrated that placing the short peptide between the first and second cysteine residues in arachnid toxins results in increased in vitro stability and bioavailability, as well as low cytotoxicity. Conclusion Arachnid toxins with an inhibitory cystine knot can be considered as a scaffold for increasing the stability of therapeutic peptides.

Ischemia–reperfusion injury (IRI) is a common phenomenon that develops both from natural causes and during major operations. Many intracellular processes mediated by calcium ions are involved in the development of IRI. Currently, chemical calcium channel blockers are used but they have a number of limitations. In this article, we study the effect of the omega-hexatoxin-Hv1a peptide toxin, an alternative to chemical calcium channel blockers, on the mechanisms of IRI development in epithelial cell culture. The toxin was produced using solid phase peptide synthesis. IRI was caused by deprivation of glucose, serum and oxygen. The data obtained demonstrate that the omega-hexatoxin-Hv1a toxin in nanomolar concentrations is able to prevent the development of apoptosis and necrosis in epithelial cells by reducing the concentration of calcium, sodium and potassium ions, as well as by delaying rapid normalization of the pH level, affecting the mitochondrial potential and oxidative stress. This toxin can be used as an alternative to chemical calcium channel blockers for preventing tissue and organ IRI due to its low-dose requirement and high bioavailability.

Ischemic and reperfusion injury is a critical condition, as it is necessary to control cell death and maintain tissue function. Restoration of nutrient and oxygen flow causes secondary damage to ischemic cells and is called reperfusion injury. Reperfusion injury causes, on the one hand, fluctuations in ion concentration inside cells, in particular sodium ions, due to changes in the conductivity of voltage-dependent ion channels, and, on the other hand, activation of the antioxidant system as a response to oxidative stress, in which the key role is given to reactive oxygen species and nitric oxide. Thus, the effect of ion channel inhibitors on the progression of oxidative stress, apoptosis and necrosis during reperfusion is of particular interest. The aim of the study is to examine the impact of sodium channels on oxidative stress under ischemic and reperfusion injury and sodium channel blockers action. Materials and Methods. The authors studied the influence of the synthesized peptide toxin, an inhibitor of voltage-gated sodium channels, under modelled ischemia/reperfusion in CHO-K1 culture on the level of apoptosis, necrosis, and oxidative stress (concentration of reactive oxygen species, nitric oxide, and glutathione) using fluorescent dyes and fluorescence microplate reader. Results. Data obtained indicate a decreased level of apoptosis and necrosis, and a control level of nitric oxide under toxin at a nanomolar concentration. At the same time, the concentrations of reactive oxygen species and glutathione did not change. Thus, the inhibitor toxin acted as a protective agent by preventing a decrease in the nitric oxide concentration, which favorably affected the survival of the cell culture during reperfusion after ischemia.

The H/ACA snoRNA family is involved in pseudouridine biogenesis. It prevents genetic changes in cells and makes them more stable due to ribosomal RNA characteristics. Therefore, the study of H/ACA snoRNA expression in cell lines with chromosomal disorders after irradiation is of particular interest. The purpose of the study is to analyze the effect of chromosomal disorders on H/ACA snoRNA expression in radioresistant K562 and radiosensitive HL-60 cell lines after radiation exposure. Materials and Methods. K562 and HL-60 cell lines were exposed to radiation (4 Gy). H/ACA snoRNA expression was analyzed by NGS sequencing (1, 4, and 24 hours after irradiation). Results. The authors revealed differences in H/ACA snoRNA expression by chromosomes in the studied cell lines, as well as the impact of chromosomal abnormalities on H/ACA snoRNA expression after radiation exposure. Changes in the copy number of normal chromosomes lead to minor changes in H/ACA snoRNA expression. Marker chromosomes disrupt H/ACA snoRNA expression. Thus, is becomes impossible to use H/ACA snoRNAs located in abnormal chromosomes as radioresistance markers. Moreover, marker chromosomes decrease the number of H/ACA snoRNAs expressed in K562, despite the greater amount of genetic material.

Despite its efficacy, radiation therapy faces the challenges connected with accelerated reproduction of tumor cells and radioresistance of malignant neoplasms. The aim of the study was to analyze the impact of the gene expression level and intermolecular interaction networks on the development of tumor cell radioresistance. Materials and Methods. The authors used 4 tumor cell lines: (K562, HCT-116p53 (+/+), HCT-116p53 (–/–), and Me45. To study the cell line transcriptome. Affymetrix high-density hybridization DNA chips (HGU133A series) were used. Bioinformatic analysis of gene expression dynamics was performed using the original Gene Selector program. Intermolecular interaction networks were studied using the STRING online system. Results. After exposure to ionizing radiation at a dose of 4 Gy, the expression level of DAAM1, IFNAR2, PALLD, and STK17A genes increases in K562 cell line and decreases in HCT-116p53 (+/+), HCT-116p53 (–/–) and Me45. Numerous protein complexes of the studied genes were found with STRING online system. Thus, DAAM1, IFNAR2, PALLD, and STK17A genes influence the activity of some particles in the network of intermolecular interactions. Selected DAAM1, IFNAR2, PALLD and STK17A genes and protein-protein complexes encoded by DAAM1, TNK2, PTBP2 and DVL2; IFNAR2, STAT2, IRF9, JAK1, GNB2L1 and IFNAR1; PALLD, LPP and ACTN2 genes can be used as potential targets. Their modulation can increase the response of malignant neoplasm cells to ionizing radiation.

Prostate cancer is the most common type of cancer in males. Approximately 1.3 million cases of prostate cancer and over 400,000 deaths from the disease are diagnosed annually. The number of deaths is expected to double by 2040. Common methods of prostate cancer treatment have many disadvantages; one of them is the relapse risk. The shortcomings of traditional therapy have led to peptide-receptor radionuclide therapy. The aim of the study is to examine binding efficiency of Lu177 labeled knottins containing PSMA-tropic peptide in different domains in vitro and their biodistribution in vivo. Materials and Methods. We used prostate cancer cell (LNCaP, PC3) and ovarian fibroblast cell (CHO-K1) cultures. The peptides were synthesized using a peptide synthesizer (ResPepSL, Intavis). We studied peptide stability, their toxicity, binding to cell cultures, and biodistribution on the example of breast adenocarcinoma-bearing BALB/c mice. Chromatographic methods and radiometric techniques were used. Results. The synthesized peptides with GTIQPYPFSWGY sequence inserted into U5-cytotoxin-Sth1a node are more stable in blood plasma and saline than 177Lu-PSMA-617a, but have a similar degree of binding. Biodistribution studies in BALB/c mice show a higher binding index of the synthesized peptide if compared to 177Lu-PSMA-617. Conclusion. Modified peptides with a PSMA-tropic peptide inserted into the structure of U5-Sth1a toxin demonstrate high stability both in saline and in blood plasma, as well as good binding to cell cultures and tumors.

Melanoma is characterized by an aggressive development and a large number of metastases during diagnostics. Photodynamic therapy (PDT) is used to treat this type of cancer. However, the accumulation of photosensitizers is observed not only in malignant tumors, but also in high metabolic rate organs. Shortcomings of melanoma therapy can be eliminated using the complex effect of laser radiation and local administration of inhibitors of cellular processes. The goal. To study the complex effect of low-intensity laser radiation and potassium channel peptide inhibitor on melanoma cell survival. Materials and Methods. A875 melanoma cells were exposed to Kappa-theraphotoxin-Gr1b toxin and laser irradiation. The authors examined the level of apoptosis and necrosis in cells using fluorescence microscopy techniques. The xCELLigence system was used to assess the cytotoxic response of A875 melanoma cells. Results. The maximum number of apoptotic and necrotic cells was observed in the group of patients with A875 tumor cells exposed to a combination of Kappa-TRTX-Gr1b toxin and laser radiation (wavelength=1265 nm). This is due to the inhibition of potassium channels of intracellular cell membranes by Kappa-TRTX-Gr1b peptide, which are associated with the apoptosis. Conclusion. Selective potassium channel inhibition under pathological processes can be regarded as a significant supplement to the superficial malignant neoplasm complex therapy. The combination of toxin and irradiation will make it possible to potentiate their action and avoid the main PDT disadvantages. This approach unites the benefits of the local administration and precise exposure on the malignant tumor.

In this paper, we have studied the role of chromosomal abnormalities in the expression of small nucleolar RNAs (snoRNAs) of radioresistant (K562) and radiosensitive (HL-60) leukemia cell line. Cells were exposed to an X-ray dose of 4 Gy. SnoRNA expression was investigated using NGS sequencing. The distribution of expressed snoRNAs on chromosomes has been found to be different for two cell lines. The most significant differences in the expression of snoRNAs were found in the K562 cell line based on the analysis of the dynamics of log2fc values. The type of clustering, the number and type of snoRNAs slightly differed in the chromosomes with trisomy and monosomy and had a pronounced difference in pairs with marker chromosomes in both cell lines. In this study, we have demonstrated that chromosomal abnormalities alter the expression of snoRNA after irradiation. Trisomies and monosomies do not have such a noticeable effect on the expression of snoRNAs as the presence of marker chromosomes.