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Vol 30, No 3 (2025)
Reviews
Cancer therapies targeting the STING pathway
Abstract
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.
156-169
Targeted NGS panels in cancer: international standards and Russian solutions for personalized medicine
Abstract
A personalized approach is a priority in the diagnosis and treatment of cancer. Accurate diagnostic tests for assessing the tumor’s molecular characteristics and optimizing the treatment strategy are essential for effective personalized treatment. Multigene NGS panels simultaneously detect a variety of genetic disorders, including single nucleotide substitutions, insertions and deletions, DNA copy number variations, translocations, microsatellite instability, and tumor mutational burden. This is crucial for selecting targeted therapy and immunotherapy, assessing prognosis, and monitoring the progression of cancer. This review discusses the evolution of precision oncology in the 21st century, the possibilities and advantages of NGS in molecular oncology, the technical and analytical characteristics of various multigene NGS panels with both amplification-based and hybridization-based enrichment, and their clinical applications in molecular diagnostics. The review focuses specifically on existing Russian and international NGS technologies. It examines available Russian and international multigene NGS panels, including problems of their application in routine cancer care in Russia.
170-181
Search for New antineoplastic agents based on structural modifications of steroidal 5α-reductase, 17β-hydroxysteroid dehydrogenase, and 17α-hydroxylase/17,20-lyase inhibitors
Abstract
This review discusses recent research on optimizing the structure of existing steroidal inhibitors of three key steroidogenic enzymes (5α-reductase, 17β-hydroxysteroid dehydrogenase [17β-HSD], and 17α-hydroxylase/17,20-lyase [CYP17A1]) used as antineoplastic agents. Furthermore, the review examines the prospects for developing new antineoplastic agents based on the obtained optimized structures. The review consists of three chapters and includes the structures of 209 new compounds, as well as laboratory and preclinical data to assess their therapeutic potential. The findings indicate that modifying the structure of the assessed steroidal inhibitors as a promising approach to developing new antineoplastic agents. The review did not include research on optimizing the structure of non-steroidal 5α-reductase, 17β-HSD, and CYP17A1 inhibitors. The search was performed in six online databases: Scopus, PubMed, Web of Science, SciFinder, ScienceDirect, and Google Scholar, and focused on existing 5α-reductase, 17β-hydroxysteroid dehydrogenase, and CYP17A1 inhibitors. The initial search was conducted using relevant keywords. The clarifying search was conducted using the following keywords: производные андростана (androstane derivatives), абиратерон (abiraterone), финастерид (finasteride), противоопухолевая активность (antineoplastic activity), etc. After removing duplicates and non-full-text articles, the review included 92 publications.
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Original Study Articles
From 2D to 3D in vitro models of nasal septal squamous cell carcinoma: tumor-associated gene expression under normal conditions and after neutron exposure
Abstract
BACKGROUND: Nasal cancer is one of the most challenging cancers for dosimetric planning in radiotherapy. The RPMI-2650 cell line is the most available for modeling in this squamous cell carcinoma. However, there are few published studies on the biological effects of irradiation in RPMI-2650-based models.
AIM: The work aimed to examine changes in tumor-associated gene expression when switching from a 2D to 3D human model of nasal septal squamous cell carcinoma and assess the response of tumor cells to a single neutron exposure.
METHODS: The phenotype of RPMI-2650 cells was assessed by immunocytochemical staining. 3D spheroids were formed using ultra-low attachment plates. An NG-14 neutron generator was used for neutron exposure of 2D and 3D models. The expression of tumor-associated genes was assessed using real-time reverse transcription polymerase chain reaction.
RESULTS: The RPMI-2650 cell line had a keratin 17+ vimentin+ phenotype, which is typical of cell lines isolated from primary tumor metastases. There was a 6.9-fold increase in keratin 17 and keratin 10 gene silencing, along with an increase in the relative expression of CDH1 by 4.9 times, CD44 by 4.4 times, VIM by 12.4 times, TP63 by 3.2 times, PIK3CA by 2.7 times, TGFB1 by 3.8 times, MMP2 by 13.1 times, and TIMP2 by 35 times. CDKN2A expression increased in both 2D and 3D models 24 hours after neutron exposure (4.7 and 6.7 times, respectively). Furthermore, KRT10 and TIMP1 expression increased (5 and 4.5 times, respectively; spheroids only), as did TIMP2, TP63, and CD44 expression (6.8, 6.5, and 9.3 times, respectively; monolayer culture only). Vimentin gene expression increased 22 times in the exposed 2D model and reduced 7 times in the cancer 3D model.
CONCLUSION: Switching from 2D to 3D RPMI-2650 models was associated with decreased expression of genes encoding tumor cell resistance to therapy, with a simultaneous increase in the expression of genes responsible for progression, metastasis, and drug resistance in squamous cell carcinoma of head and neck. A single neutron exposure in a monolayer culture increased the expression of genes associated with an unfavorable outcome. In the 3D model, neutron exposure induced a more complex response, including cell cycle regulation, fibrosis, and specific cytoskeleton remodeling.
194-205
Obtaining and characterizing rhodamine B immunoconjugates
Abstract
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.
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Effect of hyaluronic acid on drug resistance in 3D in vitro models of brain tumors
Abstract
BACKGROUND: On-treatment drug resistance is a major concern in brain tumor therapy, significantly reducing the efficacy of conventional chemotherapy. Three-dimensional (3D) cell models are a powerful tool in experimental oncology for assessing drug resistance mechanisms in tumor cells, including the role of extracellular matrix-activated signaling pathways.
AIM: The work aimed to assess the effect of hyaluronic acid on doxorubicin resistance in 3D in vitro models of brain tumors.
METHODS: 2D monolayer cultures were obtained from continuous cell lines of brain tumors in laboratory animals. The cell lines were derived from the unique collection of the A.P. Avtsyn Research Institute of Human Morphology of the B.V. Petrovsky Russian Research Center of Surgery. 3D spheroids were formed using ultra-low attachment plates with or without hyaluronic acid. The cytotoxicity of doxorubicin was assessed using the ССК-8 kit. Fluorimetry was used to measure doxorubicin efflux efficiency and CD44 production, whereas flow cytometry was used to assess the fraction of CD44+ cells. The expression of genes responsible for drug resistance was assessed using real-time polymerase chain reaction.
RESULTS: The IC50 of doxorubicin in 2D models was as follows: 180 nM for oligodendroglioma 51/7, 280 nM for glioblastoma 14-60-4, 500 nM for astrocytoma 10-17-2, and 2750 nM for neurinoma RGGN2. The IC50 of doxorubicin determined for 2D models had no significant effect on the viability of cells in spheroids. However, a fourfold increase in its concentration induced a cytotoxic effect, the severity of which was determined by spheroid compaction. Hyaluronic acid increased doxorubicin resistance in 3D models of brain tumors in a dose-dependent manner. This effect was associated with CD44 receptor activation and enhanced drug efflux from cells, which were mediated by changes in the expression of ABC transporter genes (Abcb1, Abcg2, Abcc1) and DNA repair genes (Mgmt, Top2a).
CONCLUSION: The findings clarify the role of hyaluronic acid and the CD44 receptor in drug resistance in brain tumors, facilitating the development of more relevant in vitro models. Furthermore, the findings have practical significance for developing drug resistance-overcoming strategies, such as targeted inhibition of ABC transporters or suppressed interactions between hyaluronic acid and its CD44 receptor.
220-233
In vitro antiproliferative activity and in vivo antitumor effect of 2,21-bis-[2-pyridinyl]methylidene hollongdione Dp-41 (2NK), a novel hollongdione derivative
Abstract
BACKGROUND: Natural tetracyclic triterpenes, such as dammarane-type triterpenes, have demonstrated diverse pharmacological activities, including significant anti-inflammatory and antitumor properties, making them promising candidates for novel antitumor agents. However, their limited bioavailability and inadequate effects have driven research into targeted structural modifications to enhance their biological activity.
AIM: This study aimed to evaluate the cytotoxic and antitumor activities of a new arylidene derivative of hollongdione: 2,21-bis-[2-pyridinyl]methylidene hollongdione.
METHODS: The cytotoxicity of the study derivative was evaluated using MTT assay. Flow cytometry was performed to assess cell cycle and apoptotic activities using ADAMII™ LS. The in vivo antitumor effect was evaluated using HCT116 human colon cancer xenograft models in Danio rerio embryos.
RESULTS: 2,21-bis-[2-pyridinyl]methylidene hollongdione Dp-41 (2NK) demonstrated cytotoxic activity in DU145 (0.70 ± 0.03 µM), HCT116 (0.99 ± 0.01 µM), Panc1 (0.20 ± 0.03 µM), and A549 (0.60 ± 0.04 µM) cell cultures. In the HCT116 human colon cancer xenograft model in Danio rerio embryos, it achieved 72% tumor growth inhibition, thus demonstrating antitumor activity.
CONCLUSION: Dp-41 (2NK) exhibited significant antiproliferative activity against prostate, colon, pancreatic, and lung cancer cell lines, as well as against HCT116 human colon cancer xenografts in Danio rerio embryos.
234-246
Biological activity of SAD-2: a novel original STING pathway activator
Abstract
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.
247-258
Association between sensitivity to L-asparaginase in human cutaneous melanoma cells and asparagine synthetase and glutamine synthetase gene expression
Abstract
BACKGROUND: L-asparaginase is an enzyme used in clinical practice for the treatment of some blood cancers. It has an antiproliferative effect in some solid tumors. To increase the efficacy of L-asparaginase, it is relevant to identify markers that predict tumor sensitivity to this enzyme. The expression of the ASNS and GLUL genes in tumor cells was previously proposed as such a marker. However, for some tumors, including melanoma, data on the association between the expression of these genes and sensitivity to L-asparaginase are absent or limited.
AIM: The work aimed to assess the association between sensitivity to L-asparaginase in melanoma cells and expression of the ASNS and GLUL genes.
METHODS: The cytotoxicity was assessed using the MTT assay in 35 cell lines. Gene expression was assessed using real-time reverse transcription polymerase chain reaction. The Spearman’s correlation coefficient was used to assess the association between expression and sensitivity.
RESULTS: The calculated IC50 for L-asparaginase in melanoma cell cultures was 0.01–199.91 IU/mL (median: 2.96 IU/mL; arithmetic mean: 16.95 IU/mL). The ASNS gene expression was 0.02–7.38 (median: 0.4; arithmetic mean: 0.98). The GLUL gene expression was 0.06–14.78 (median: 0.64; arithmetic mean: 1.41). The correlation between IC50 and ASNS expression was confirmed by the Spearman’s correlation coefficient of 0.751. There was no correlation between IC50 and GLUL expression (Spearman’s correlation coefficient: 0.077).
CONCLUSION: A positive correlation was confirmed between melanoma cell resistance to L-asparaginase and ASNS gene expression in these cells. A similar correlation for the GLUL gene was not confirmed.
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