Olga N. Solopova

Background. One of the key components of innate immune signaling pathways, the STING (STimulator of INterferon Genes) protein, is currently a promising target for cancer immunotherapy. Activation of STING leads to the production of inflammatory cytokines, in particular type 1 interferons, which provide an antitumor immune response. The clinical potential of STING agonists is limited by their systemic toxicity due to their relatively non-specific action. One of the approaches to expand the therapeutic index of drugs is to modify the native structure of STING agonists to make them more sensitive to physiologically relevant stimuli. Another approach is to develop efficient delivery system that reduce the impact of encapsulated STING agonists on healthy tissues. Aim. Systematization and generalization the literature data on the development of delivery systems of STING agonists based on immunoconjugates, liposomes, and polymer nanoparticles. Results. The delivery systems discussed show significant potential for enhancing the efficacy of STING agonist-based immunotherapy for malignant neoplasms. As substances exhibiting therapeutically relevant activity in the nanomolar concentration range, STING agonists represent a suitable candidate as a payload of immunoconjugates. During the pharmaceutical development of such a delivery system, it is necessary to take into account the properties of its structural components, primarily the STING agonist itself. The result is almost always a unique product: a molecular construct capable of selectively delivering the STING activator to the tumor microenvironment while minimizing systemic side effects. Encapsulation of STING agonists, particularly cyclic dinucleotides, within nanoparticles serves as an effective tool for increasing their in vivo stability, improving cellular uptake, and reducing systemic toxicity. Conclusion. The development of innovative delivery systems is a critical factor for the successful clinical implementation of STING agonist-based biotherapy for malignant neoplasms. The flexibility of the structure of nanoplatforms allows for their further modification and optimization, including the improvements in manufacturing technology to obtain a stable product with specified characteristics.

Introduction. Infection of canids with canine parvovirus (CPV), especially in puppies, leads to serious damage to the gastrointestinal tract in a short period of time, up to a fatal outcome. In this regard, early and rapid diagnosis is crucial for initiating therapy and preventing the spread of infection. In this connection, immunochromatographic analysis (ICA) is the preferred method because it allows rapid detection of virus infection. In addition, this method is highly specific and does not require complex laboratory equipment, which greatly simplifies its use in comparison with other common methods for detecting canine parvovirus. The aim of this study is the development of an ICA test system for the detection of the VP2 protein of canine parvovirus. Materials and methods. Monoclonal antibodies to the recombinant VP2 protein of canine parvovirus were obtained using hybridomic technology. Colloidal gold is synthesized by the citrate method. Results. Monoclonal antibodies (MABs) against the VP2 protein of canine parvovirus were obtained and characterized, colloidal gold (AuNPs) was synthesized, the conditions for conjugation of MABs with AuNPs were selected, and the optimal ratios of the components of the test system were determined. The visual limit detection (vLOD) was 1.56 ng/mL. The developed ICA test system has shown high diagnostic efficiency in model experiments with a known concentration of VP2, as well as in sick animals with a confirmed diagnosis. Conclusion. An ICA test system has been developed to determine the VP2 protein of canine parvovirus. The resulting test system can be used as a fast and effective diagnostic tool for detecting CVP in the canine clinical specimens.

BACKGROUND: STING pathway activators with targeted delivery to tumor nodules are a promising option in cancer immunotherapy, especially as immunoconjugates. Existing compounds, such as MSA-2, are insufficiently effective as active immunoconjugate components, necessitating the development of new, more active compounds. AIM: The work aimed to examine the biological activity of the new compound SAD-2 and assess its potential as a new immunobiological drug for cancer therapy. METHODS: The work used contemporary methods of fine organic synthesis and analysis of the resulting compounds. MSA-2 was obtained from veratrole by multistage synthesis. SAD-2 was synthesized from MSA-2 by esterification with isopropyl alcohol in the presence of thionyl chloride. The antiproliferative activity of the compounds was assessed by the MTT method using colorectal cancer cell lines and human peripheral blood mononuclear cells. The induction of the interferon beta gene was assessed by real-time polymerase chain reaction using the human monocytic cell line THP-1. RESULTS: The new compound SAD-2 had 200–500 times higher antiproliferative activity according to IC50 than the existing compound MSA-2. Both MSA-2 and SAD-2 are active only in the presence of immune cells. SAD-2 showed 5–60 times higher relative induction of the IFNB1 gene than MSA-2, depending on the incubation time. CONCLUSION: SAD-2 is a promising new compound for developing immunoconjugates for targeted STING pathway activation in tumor nodules.

BACKGROUND: Monoclonal antibody (mAb)–drug immunoconjugates are a promising option in cancer immunotherapy. However, developing effective techniques of their synthesis remains relevant, especially when a small molecule has no mAb binding sites. AIM: The work aimed to synthesize immunoconjugates based on two modified rhodamine B molecules and four mAbs, and to examine their molecular and functional properties. METHODS: mAbs were conjugated to Rod-SMCC via reduced disulfide groups of immunoglobulin G (IgG). Rod-piperazine was added to oxidized IgG oligosaccharides. The synthesis was assessed using spectrophotometry. The activity of the resulting conjugates was assessed using enzyme-linked immunosorbent assay. The molecular heterogeneity of the resulting conjugates was assessed using high-performance chromatography. RESULTS: Rod-SMCC produced conjugates with all examined antibodies via thiol groups, with maximum saturation for each antibody. The maximum incorporation rate of approximately 10.96 ± 1.3 mol Rod per 1 mol IgG was observed for ICO 204, with approximately 5.19 ± 1.75 for trastuzumab. These Rod incorporation rates decreased after additional fractionation of the resulting immunoconjugates on a separating gel, amounting to 7.94 ± 1.8 for ICO 204 and 3.32 ± 1.2 for trastuzumab. The antigen-binding activity of ICO 204 immunoconjugates was comparable to that of native antibodies. The incorporation of Rod in immunoconjugates depended on the mAb fractionation technique. Acid elution during mAb fractionation on protein G decreased the incorporation of Rod in immunoconjugates. Rod-piperazine produced immunoconjugates with ICO 204 and trastuzumab via oxidized carbohydrate residues of antibodies. The maximum incorporation rate of rhodamine B in ICO 204 was 2.3 ± 0.3 mol per 1 mol IgG, with 0.2 ± 0.12 for trastuzumab. CONCLUSION: Chemical synthesis was used to produce two derivatives of Rod, which initially had no IgG binding sites. These compounds were used to synthesize model immunoconjugates with high Rod incorporation rates while maintaining antigen-binding activity. This work demonstrated that immunoconjugates can be produced using pharmaceutical substances with carboxyl groups that are unsuitable for such synthesis. Furthermore, it was shown that immunoconjugates can be synthesized through carboxyl group modification of pharmaceutical substances using piperazine and SMCC.

Modern oncology needs to develop and implement antineoplastic agents that provide sustained remission without serious side effects. Immunotherapy and targeted therapy agents that activate innate immunity may address this issue. The stimulator of interferon genes (STING), an intracellular protein, mediates the synthesis of type I interferons, which have antiviral, antitumor, and antiproliferative properties. The multifaceted effects of interferons may be beneficial in cancer therapy. However, potential side effects of systemic interferon therapy underlie the need for the methods of stimulating them locally in the tumor nodule by targeting the STING pathway. STING is directly activated by the cyclic dinucleotide cGAMP. It is synthesized by the cyclic GMP-AMP synthase (cGAS) from adenosine triphosphate and guanosine triphosphate. However, cGAMP cannot be used as a therapeutic agent because it is unstable and only persists in the cell for a short period of time before being hydrolyzed. Therefore, researchers all over the world are working to synthesize new activators of the STING pathway. In cancer therapy, using STING activators as part of an immunoconjugate for targeted delivery to the tumor nodule is considered more effective. A monoclonal antibody against a tumor-specific antigen is the second component of the immunoconjugate. Given the high risk of tumor cell resistance to cytostatic drugs commonly used in current clinical practice, an immunoconjugate with a STING activator may provide advantages over existing therapies. Several immunoconjugates have already been tested in preclinical studies and are considered promising for drug development. However, further research is needed to study the properties of new compounds and improve their efficacy and tolerability. The search was performed in PubMed, eLIBRARY.RU, Google Scholar, NCBI ClinicalTrials, and PubChem and included publications from June to August 2025. The following search terms were used: STING protein, cGAS protein, cGAS-STING pathway, IFN-β, interferon-based treatment, type I IFN induction, antibody-drug conjugate, STING activation, STING agonist, and HER2-targeted therapies.

Background. Ferroptosis is a type of non-apoptotic iron-dependent form of regulated cell death. Ferroportin is the only exporter of iron from cells, however, the involvement of ferroportin in cell ferroptosisis poorly understood. Activation or blocking of ferroptosis pathways may provide a therapeutic strategy for the treatment of a number of diseases. Control of ferroportin expression will make it possible to select a more effective tumor therapy. Obtaining monoclonal antibodies to human ferroportin will help to further study its role in ferroptosis of tumor cells.Aim. Obtaining and characterization of monoclonal antibodies to human ferroportin.Materials and methods. Mouse monoclonal antibodies against a synthetic peptide corresponding to the ferroportin protein region were obtained using hybridomic technology. The peptide was synthesized by the method of solid-phase automatic synthesis.Results. A 15-membered peptide with the sequence ELKQLNLHKDTEPKP (ELK) was selected and synthesized. Conjugates of the synthetic peptide with carrier proteins were obtained. 4 stable hybridomic clones were obtained, and samples of monoclonal antibodies were obtained. The samples were successfully tested using methods of flow cytometry, enzyme immunoassay, and polyacrylamide gel electrophoresis.Conclusion. Four antibodies against ferroportin binding the ELK peptide were obtained and characterized. The antibodies can be used in further studies of iron transport in tumor cells.

Bioresource collection of the N. N. Blokhin National Medical Research Center of Oncology is a unique structured biobank that combines different types of primary and subsidiary samples and ensures its comprehensive characterization, including both generally accepted indicators and specific types of research. Samples of paraffin blocks, frozen material, blood and its derivatives are deposited in the clinical department of the center. The research institute of the center has collected commercial and unique human cell lines and transplantable strains obtained from clinical material, as well as cells from laboratory animals, mainly of mouse origin. The provided cell lines undergo multi- stage quality control, including confirmation of authenticity, assessment of viability and determination of optimal cultivation conditions, analysis of interspecific and intraspecific contamination, study of tumorigenicity and reproducibility in athymic Balb/ c-nude mice, etc. In addition, the Bioresource Collection has hybridoma clones that produce antibodies to a wide range of targets. The Center provides the opportunity to conduct preclinical research using samples from the Bioresource Collection to obtain scientific and regulatory data on the antiproliferative activity of new agents or methods for cancer treatment.

The evolutionary conserved DNA-sensing cGAS-STING innate immunity pathway represents one of the most important cytosolic DNA-sensing systems that is activated in response to viral invasion and/or damage to the integrity of the nuclear envelope. The key outcome of this pathway is the production of interferon, which subsequently stimulates the transcription of hundreds of genes. In oncology, the situation is complex because this pathway may serve either anti- or pro-oncogenic roles, depending on context. The prevailing understanding is that when the innate immune response is activated by sensing cytosolic DNA, such as DNA released from ruptured micronuclei, it results in the production of interferon, which attracts cytotoxic cells to destroy tumors. However, in tumor cells that have adjusted to significant chromosomal instability, particularly in relapsed, treatment-resistant cancers, the cGAS–STING pathway often supports cancer progression, fostering the epithelial-to-mesenchymal transition (EMT). Here, we review this intricate pathway in terms of its association with cancer progression, giving special attention to pancreatic ductal adenocarcinoma and gliomas. As the development of new cGAS–STING-modulating small molecules and immunotherapies such as oncolytic viruses involves serious challenges, we highlight several recent fundamental discoveries, such as the proton-channeling function of STING. These discoveries may serve as guiding lights for potential pharmacological advancements.

In this study, a lateral flow immunoassay (LFIA) was developed to detect okadaic acid (OA) belonging to the diarrheic shellfish poisoning group of aquatic toxins. Newly obtained anti-OA monoclonal antibodies and bimetallic core@shell Au@Pt nanoparticles were used in the indirect format of the LFIA. Peroxidase-mimicking nanozyme properties of Au@Pt enabled using them to enhance band coloration on the test strips and, consequently, for increasing the LFIA sensitivity. The instrumental limit of detection (LOD), the working range of detectable concentrations, and the visual cutoff of the assay were 0.5, 0.8–6.8, and 10 ng/mL, respectively. The assay duration was 20 min. The rapid and simple sample preparation procedure was applied for seawater, river water, and fish samples. The total duration of the sample pretreatment and LFIA was 25/40 min for water/fish samples, ensuring testing rapidity. The developed test system provides sensitive control of raw materials and food products and can be used to detect OA at all stages of the food industry «from sea to fork» chains.

Aquatic toxins are a group of toxic compounds produced by several types of freshwater and marine algae and cyanobacteria and transported through the food chains of water bodies. Potential contamination of aquaculture products (raw and processed fish and seafood) with aquatic toxins requires the use of efficient screening methods for their control. In this study, a multiplex immunochromatographic test system for the simultaneous detection of three aquatic toxins—phycotoxins domoic acid (DA) and okadaic acid (OA), and cyanotoxin microcystin-LR (MC-LR)—is for the first time developed. For this, a competitive indirect immunochromatographic analysis (ICA) based on gold-labeled secondary antibodies was carried out. The LODs/cutoffs/working ranges of the ICA were 0.05/0.3/0.07–0.29, 1.3/100/3.2–58.2, and 0.1/2.0/0.2–1.1 ng/mL for MC-LR, DA, and OA, respectively. The assay duration was 18 min. The developed test system was used to analyze water samples from natural sources (salt and fresh water) and fish samples. For sample preparation of water, simple dilution with a buffer was proposed; for fish samples, methanol–water extraction was utilized. It was demonstrated that the triple LFIA specifically detected target aquatic toxins with recoveries of 85.0–121.5%. The developed multiplex LFIA can be considered a promising analytical solution for the rapid, easy, and sensitive control of water and food safety. Graphical abstract