Efficacy of antiangiogenic treatments is often linked to the complex interplay between tumor vascularization and oxygenation. Yet their relationship remains difficult to assess in vivo due to limitations of conventional clinical imaging techniques. We used a combination of noninvasive optoacoustic (OA) angiography and diffuse optical spectroscopy (DOS) to investigate the effects of the antiangiogenic therapy on vascular structure and oxygenation in subcutaneous xenograft model of Colo320 colon adenocarcinoma. Axitinib, a tyrosine kinase inhibitor targeting VEGF receptors, was administered into animals at 50 mg/kg, five days per week for four weeks. Raster-scan OA imaging was performed using 532 nm pulsed laser source and a wideband polyvinylidene difluoride (PVDF) detector. DOS measurements were conducted using a fiber-optic-based reflectance system. Immunohistochemical (IHC) analysis for CD31 and the hypoxia marker pimonidazole was used for validation. Axitinib treatment resulted in a thirtyfold reduction in the median tumor volume. OA imaging revealed reductions in volumetric vessel fraction and projected vessel area, while DOS showed a transient increase in blood oxygen saturation. IHC confirmed a decrease in microvessel density post-treatment and indicated larger hypoxic areas in treated tumors compared to controls at the experimental endpoint. The newly introduced approach thus facilitates experimental studies aiming at optimization of antiangiogenic treatment regimens and their subsequent combination with other treatment modalities, such as radiation therapy, where effectiveness may strongly depend on the vascular network condition and tumor oxygenation levels.

164 Background: Aberrant activation of fibroblast growth factor receptor (FGFR) pathways contributes to tumor progression in colorectal cancer (CRC), often through ligand-mediated stimulation of extracellular domains. To address this, we evaluated the preclinical activity of OM-RCA-01, a humanized monoclonal antibody selectively targeting FGFR1, and compared its efficacy with bevacizumab and chemotherapy in preclinical models. Methods: For in vitro study, SW620 and HCT116 CRC cells with confirmed FGFR1 expression were exposed to OM-RCA-01, bevacizumab, or their combination at concentrations ranging from 2×10⁻⁴ to 10⁻⁷ g/ml (prepared by serial 1:2 dilutions). Following antibody treatment, cells were stimulated with FGF2 (5 ng/ml), or VEGF (10 ng/ml), or both ligands, and proliferation was quantified. For in vivo study, SW620 cells were implanted subcutaneously into the thighs of female NU–A/A Tyrc/Tyrc Foxn1nu/Foxn1nu mice. When tumors reached ~150 mm³, animals were randomized to receive: 1) OM-RCA-01 (30 mg/kg, i.p., twice weekly for 3 weeks); 2) bevacizumab (5 mg/kg, i.p., twice weekly for 3 weeks); 3) OM-RCA-01 + bevacizumab combination; 4) 5-fluorouracil (30 mg/kg, i.p., on Days 1–3 of each week for 3 weeks); 5) triple combination, or 6) saline control. Tumor dimensions were recorded every 3 days for 4 weeks. Results: In vitro, FGF2 stimulation markedly increased proliferation of both cell lines, which was dose-dependently inhibited by OM-RCA-(IC₅₀ < 25 μg/ml). Bevacizumab had no measurable effect on either FGF2- or VEGF-driven proliferation (IC₅₀ > 100 μg/ml). However, combining bevacizumab with OM-RCA-01 under dual FGF/VEGF stimulation produced a more pronounced inhibitory effect (IC₅₀ 11.2–20 μg/ml). In vivo, all treatment regimens significantly reduced tumor burden compared with saline control (Table). OM-RCA-01 monotherapy showed robust tumor suppression (P < 0.0001), with a median tumor volume of 956.7 mm³ versus 2129.9 mm³ in controls at study endpoint. The dual-antibody approach yielded tumor/control ratios (T/C) similar to either monotherapy (47.1% vs. 52.5% vs. 44.9%). Notably, the triple combination of OM-RCA-01, bevacizumab, and 5-FU demonstrated the greatest antitumor activity, achieving the smallest median tumor size (633.7 mm³; T/C = 29.8%), consistent with a synergistic interaction. Conclusions: Targeting FGFR1 effectively inhibited CRC cell proliferation and tumor progression in preclinical models. While dual FGFR1/VEGF antibody therapy did not enhance antitumor efficacy compared with single agents, the addition of chemotherapy produced a marked improvement in therapeutic activity. Tumor growth inhibition. Vehicle OM-RCA-01 Bevacizumab OM-RCA-01 + Bevacizumab 5-FU OM-RCA-01 + Bevacizumab + 5-FU Tumor volume, median, mm 3 2129.9 956.7 1117.1 1003.8 895.6 633.7 T/C% – 44.9 52.5 47.1 42.1 29.8 TGI% – 55.1 47.6 52.9 58.0 70.3

Fibroblast growth factor receptor (FGFR) signaling in colorectal cancer (CRC) can be driven by ligand-dependent activation of its extracellular domains. We hypothesized that selective targeting of the extracellular II–IIIc domains using OM-RCA-01 - a humanized monoclonal antibody against FGFR1 - may offer an effective therapeutic strategy in FGFR1-expressing CRC. In vitro, SW620 cells were treated with OM-RCA-01 (2×10-4 to 1.25×10-5 g/ml, serial 1:2 dilutions), followed by FGF2 (5 ng/ml), and cell proliferation was assessed. Additionally, metastatic tumor tissue surgically resected from FGFR1-expressing CRC patients (Cell Signaling) was rinsed in PBS containing antibiotics/antimycotics, then mechanically minced. Cell culture was incubated in the presence of FGF2 (50 ng/ml), following the protocol described by Otte et al. (Sci Rep, 2019). To assess FGFR1 inhibition, OM-RCA-01 was added to the culture medium at a concentration of 30 µg/ml. DMSO was added at an equivalent dilution in control experiments. In vivo, SW620 cells with high FGFR1 expression were subcutaneously implanted into the thighs of female NU–A/A Tyrc/Tyrc Foxn1nu/Foxn1nu mice. Once tumors reached 150 mm3, animals were randomized to receive either OM-RCA-01 (30 mg/kg, intraperitoneally, twice weekly for 3 weeks) or saline control. Tumor volumes were measured every 3 days over a 4-week period. In vitro, FGF2 stimulation markedly increased proliferation, which was dose-dependently inhibited by OM-RCA-01 (EC50 = 4.3 × 10-5 g/ml). In Patient experiment 1, spheroid formation could not be established under FGFR1 inhibition, whereas robust spheroid growth was observed in the control group. In Patient 2, spheroids initially formed but ceased growing after 10 days of treatment with the FGFR1 inhibitor. In vivo, FGFR1 inhibition with OM-RCA-01 significantly suppressed tumor growth compared to control (P < 0.0001). Median tumor volume at study endpoint was 956.7 mm3 in the treatment group versus 2129.9 mm3 in vehicle. No tumors in the antibody-treated group exceeded 2000 mm3, whereas all control tumors reached this size by day 28. Selective inhibition of the FGFR1 extracellular domain with OM-RCA-01 effectively suppressed FGF2-driven proliferation in vitro, blocked patient-derived CRC spheroid growth, and significantly reduced tumor growth in vivo. These findings support OM-RCA-01 as a promising targeted therapy for FGFR1-expressing CRC. Yulia Khochenkova, Dmitry Khochenkov, Yuliya Baula, Qingqing Wang, Ilya Tsimafeyeu. Extracellular FGFR1 inhibition with OM-RCA-01 humanized antibody suppresses tumor growth in FGFR1-expressing colorectal cancer models [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2025 Oct 22-26; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2025;24(10 Suppl):Abstract nr A138.

This article presents the findings of an experimental study investigating the development of the Colo 320 xenograft vasculature during both natural tumor growth and under antiangiogenic therapy (Axitinib and Alofanib), utilizing optoacoustic microscopy. The study revealed differences in vessel structure at various stages of tumor development. These results are significant for the advancement of clinical diagnostic methods for superficial neoplasms and may contribute to the development and evaluation of novel antiangiogenic therapeutics.

Objective: This study aimed to assess the expression of platelet-derived growth factor receptors alpha and beta (PDGFR!/") in primary tumor cells of patients with renal cell carcinoma (RCC). Methods: Platelet-derived growth factor receptors alpha and beta expression was analyzed in RCC specimens from 65 RCC patients (pT1a-T4NanyMany) using immunohis- tochemistry. Expression levels were quantified using the semi-quantitative H-score (HS) method, and correlations between PDGFR!/" expression and tumor characteris- tics were evaluated. The impact of PDGFR!/" expression on patient survival was also examined. Results: Platelet-derived growth factor receptor alpha was expressed in the cytoplasm and membrane of 58.5% of primary RCC cells, with an HS of 62.9 ± 8.4, significantly higher than PDGFR" expression (44.6%; 26.6 ± 5.3; P > .05). Platelet-derived growth factor receptor alpha expression correlated with tumor grade (r = 0.471; P < .0001) and the pN+ category (r = 0.280; P = .024). Platelet-derived growth factor receptor beta expression correlated with tumor grade (r = 0.286; P = .021), venous tumor thrombosis (r = 0.263; P = .034), M+ category (r = 0.305; P = .014), and adrenal metastases (r = 0.306; P = .041). Neither PDGFR! nor PDGFR" expression levels influenced patient survival. Conclusion: Platelet-derived growth factor receptor alpha was more highly expressed in RCC cells compared to PDGFR". Overexpression of PDGFR!/" was associated with higher tumor grade and advanced RCC stages, though it did not affect patient survival.

Invited for the cover of this issue are Tatiyana Serebryanskaya, Mikhail Kinzhalov and co-workers at St. Petersburg State University, the Research Institute for Physical Chemical Problems, Belarusian State University, Togliatti State University and Blokhin National Medical Research Center of Oncology. The image depicts the shield of Pallas Athena with the structure of a palladium carbene complex that protects against triple-negative breast cancer. Read the full text of the article at 10.1002/chem.202400101.

Background Fibroblast growth factor receptor 1 (FGFR1) plays a crucial role in carcinogenesis. Exploring the combination of novel humanized monoclonal anti-FGFR1 antibody OM-RCA-01 and immunotherapy was intriguing due to involvement of FGFR1 in mechanisms of resistance to checkpoint inhibitors. Methods Lung cancer A549, exhibiting distinct levels of FGFR1 expression, were cultured in basic FGF medium with OM-RCA-01 supplementation. The efficacy of antibody monotherapy was validated in a lung cancer xenograft study. To investigate whether OM-RCA-01 could enhance the efficacy of immunotherapy in vitro and in vivo, MLR/SEB assays and FGFR1/PD-L1-positive PDX model were established. Results The antibody effectively suppressed receptor phosphorylation, resulting in inhibited cell proliferation. OM-RCA-01 led to a substantial delay in tumor growth compared to non-specific IgG in a xenograft study. The median tumor volume was 1,048.5 mm3 and 2,174 mm3 in the study and vehicle groups, representing a twofold difference in favor of the anti-FGFR1 antibody. In vitro, the combination of nivolumab and OM-RCA-01 resulted in higher levels of IFNγ and IL-2 release compared with nivolumab alone. In vivo, pembrolizumab in combination with OM-RCA-01 produced a greater inhibitory effect on tumor growth compared with vehicle and pembrolizumab alone. The curve plateaued, indicating minimal tumor growth from Day 16 onwards in the combination group. The OM-RCA-01 demonstrated no toxicity, even at therapeutic doses or higher doses. Conclusions Our preclinical studies demonstrate that OM-RCA-01 exhibits robust activity with minimal toxicity. Combining an anti-FGFR1 antibody with a checkpoint inhibitor may enhance the efficacy of both drugs. However, further studies are needed to elucidate the mechanism of this interaction.

BackgroundRiboflavin (vitamin B2) is one of the most important water-soluble vitamins and a coenzyme involved in many biochemical processes. It has previously been shown that adjuvant therapy with flavin mononucleotide (a water-soluble form of riboflavin) correlates with normalization of clinically relevant immune markers in patients with COVID-19, but the mechanism of this effect remains unclear. Here, the antiviral and anti-inflammatory effects of riboflavin were investigated to elucidate the molecular mechanisms underlying the riboflavin-induced effects.MethodsRiboflavin was evaluated for recombinant SARS-CoV-2 PLpro inhibition in an enzyme kinetic assay and for direct inhibition of SARS-CoV-2 replication in Vero E6 cells, as well as for anti-inflammatory activity in polysaccharide-induced inflammation models, including endothelial cells in vitro and acute lung inflammation in vivo.ResultsFor the first time, the ability of riboflavin at high concentrations (above 50 μM) to inhibit SARS-CoV-2 PLpro protease in vitro was demonstrated; however, no inhibition of viral replication in Vero E6 cells in vitro was found. At the same time, riboflavin exerted a pronounced anti-inflammatory effect in the polysaccharide-induced inflammation model, both in vitro, preventing polysaccharide-induced cell death, and in vivo, reducing inflammatory markers (IL-1β, IL-6, and TNF-α) and normalizing lung histology.ConclusionsIt is concluded that riboflavin reveals anti-inflammatory rather than antiviral activity for SARS-CoV-2 infection.General significanceRiboflavin could be suggested as a promising compound for the therapy of inflammatory diseases of broad origin.

The demand for RNA-based therapeutics is increasing globally. However, their use is hampered by the lack of safe and effective delivery vehicles. Here, we developed technologies for highly efficient delivery of RNA cargo into programmable extracellular vesicle-mimetic nanovesicles (EMNVs) by fabricating hybrid EMNV-liposomes (Hybs). Tissue targeting is endowed by highly efficient genetic platforms based on truncated CD63 (ΔCD63) or PTGFRN proteins. For the first time we reveal their efficiency in functionalizing EMNVs, resulting in >10-fold enhancement of nanoparticle internalization in vitro and >2-fold in vivo. RNA delivery using Hybs demonstrated efficiency of >85% in human and mouse cell lines. Comparative analysis of EMNVs and Hyb lysosome colocalization and stability suggested that Hybs enter the lysosomal compartment and escape over time, whereas EMNVs primarily avoid it. Finally, we used these technologies to generate liver-targeting Hybs loaded with therapeutic small interfering RNA and demonstrated the robust efficiency of this system in vitro and in vivo. These technologies can be adapted for manufacturing a wide range of next-generation vehicles for highly efficient, safe delivery of RNA into desired organs and tissues for therapeutic and prophylactic applications.

Objective: In recent years, significant progress has been achieved in the treatment of patients with colorectal cancer, but in most cases, treatment is accompanied by the development of drug resistance. Recently discovered iron-dependent cell death, ferroptosis, provides promising therapeutic targets that might aid in reducing the recurrence rates. Methods: Derivatives of 3-hydroxyquinazoline were obtained by chemical synthesis and have a purity of at least 95

Background. The experience of using the like-SJMB03 therapeutic program is presented. The aim of this study was to assess the potential possibility of reducing the dose of craniospinal and local radiation therapy in the standard and high-risk group patients, and to identify clinical, therapeutic, morphological and molecular-biological factors that determine disease prognosis. Materials and methods. From 2008 till 2016 years 48 patients with newly diagnosed medulloblastoma were included in the study. In most cases (85%), localization of the primary tumor site was presented by a lesion of the cerebellar vermis with spread into the 4-th ventricle cavity. Gross total or near gross total resection of the primary tumor focus (R0 status) was achieved in 32 (66.7%) cases. The presence of a metastatic disease was established in 15 (31.2%) patients. Molecular biological characteristics of tumor samples were assessed using fluorescent hybridization in situ (FISH), Sanger PCR sequencing, and Illumina Infinium Human Methylation 450/850K BeadChip. Risk group stratification was according to SJMB03 (standard risk group was defined as: R0, M0 status; high-risk group: R1M0 or R0/1M+). A distinctive feature of this protocol was a reduction of the craniospinal irradiation dose down to 36 Gy for patients with M2/M3 status (without additional irradiation of metastatic foci) and the local irradiation dose down to 54 Gy (regardless of R status). Results. In the standard risk group (R0M0), 5-year and 10-year EFS were 84.0±7.3% and 67.2±9.6%, 5-year and 10-year OS were 92.0±5.4% and 76.4±9.9%, in the high-risk group (R1M0): 5-year and 10-year EFS – 62.5±17.1% and 62.5±17.1%, 5-year and 10-year OS – 75.0±15.3% and 62.5±17.1%, in the high-risk group (R0/1M+): 5-year and 10-year EFS – 33.3±12.2% and 33.3±12.2%, 5-year and 10-year OS – 60.0±12.6% and 33.3±12.2%. Structure of events was presented by 15 disease recurrences (7 localized – 2 early, 5 late; 8 disseminated – 3 early, 5 late), 2 cases of disease progression, 2 cases of secondary tumors (in the first – osteosarcoma, in the second – glioblastoma) and 2 episodes of fatal septic complications. Most of the events were found in patients with a Group 4 tumor. Two peaks of the events were established in standard risk group (the first peak was within 2 years after the end of treatment program, mainly in the age group of 8 years and older, the second peak was within 3 years after the fifth year of observation, predominantly in the group from 3 to 7 years). CSI dose reduction down to 36 Gy for patients with M2/M3 status (without additional irradiation of metastatic foci) in the high-risk group led to a dramatic decrease of 5-year EFS. There was a trend towards a decrease in 5-year EFS and OS in patients aged 8 years and older, as well as in the presence of the C-MYC, N-MYC genes amplification, isochromosome 17q in tumor cells. Conclusion. Despite the accumulated experience, it is necessary to continue studying the relationship between age groups and the molecular biology of tumor cells in medulloblastoma.

Despite the encouraging success of checkpoint inhibitors, approximately 70% of tumors can eventually become resistant over time. The tumor microenvironment, in particular cancer-associated fibroblasts (CAFs), is one of the important mechanisms of resistance. OM-RCA-01, a anti-FGFR1 humanized antibody, and alofanib, a FGFR2 allosteric inhibitor showed promising results in previous studies. Renal cancer cells (Renca; 5×105) were implanted by subcutaneous (sc) injection into C57BL/6 mice. Additional Renca cells and human kidney CAFs (1.5×106) were premixed in Matrigel and implanted sc in second cohort of C57BL/6 mice. Treatment with ipilimumab (ipi, 200 mcl on days 7, 10, and 13) was initiated in both cohorts when tumor volumes reached 70 mm3. Treatment with OM-RCA-01 (30 mg/kg every 3 days) or IgG2a isotype control was initiated after ipi when tumor volumes reached 1,500 mm3. Prostate cancer cells (DU-145; 4×106) were implanted sc in female BALB/c mice. Treatment with human anti-LAG3 antibody (1 mg/kg, biweekly) or control was initiated when tumor volumes reached 150 mm3. Treatment with alofanib (116 mg/kg, iv daily) or control was initiated when tumor volumes reached 1,900 mm3. Tumor growth was monitored by caliper measurement every 3 days. The primary endpoint was tumor growth delay (TGD) from the initiation of immunotherapy. Treatment with OM-RCA-01 resulted in higher levels of IFNγ release by 43% and increased IL-2 secretion by 65% over control. IHC showed a significantly lower number of α-SMA/FSP/vimentin-positive CAFs in the OM-RCA-01 cohort. The table summarizes the results of in vivo studies. Table: 1073PComparison between groupsTGD, % (P-value)Ipilimumab, CAFs- vs. CAFs+ cohorts44.0 (0.027)Renal cancer, CAFs+, OM-RCA-01 vs. IgG2a96.1 (<0.001)Renal cancer, CAFs-, OM-RCA-01 vs. IgG2a74.5 (<0.001)Prostate cancer, anti-LAG3 vs. control19.4 (0.035)Prostate cancer, alofanib iv vs. control69.4 (0.012) Open table in a new tab Inhibition of FGFR1 and FGFR2 following immunotherapy resulted in a twofold suppression of tumor growth, especially in the CAFs+ cohort.

Differences in the vessel fraction, hemoglobin content and oxygenation level of tumor xenografts are revealed by optoacoustic microscopy and diffuse optical spectroscopy.

During the last 30 years, unique international experience has been accumulated in the treatment of children with medulloblastoma, especially in the age group over 3 years. Evolutionary representations about one of the most well – known international protocols – SJMB (in versions since 1996 – SJMB96, since 2003 – SJMB03, since 2012 – SJMB12) are shown in this article. Innovative criteria for stratifying patients into risk groups were established according to clinical, therapeutic, morphological and molecular-biological prognostic factors. Despite the accumulated experience, it is necessary to continue studying the relationship between age groups and the molecular biology of tumor cells for the purpose of subsequent optimization of the treatment program.

The paper demonstrates the results of a study of experimental SN-12C xenograft vascular network formation using optoacoustic microscopy. A sevenfold increase in vascularity during tumor growth from days 7 to 121 was shown. The possibility of monitoring the development of individual vessels inside the tumor node has been demonstrated. The data obtained are important for understanding the mechanisms of development of the tumor vascular system and may be useful in testing antiangiogenic therapeutic agents.

In vitro/in vivo detection of copper ions is a challenging task but one which is important in the development of new approaches to the diagnosis and treatment of cancer and hereditary diseases such as Alzheimer's, Wilson's, etc. In this paper, we present a nanopipette sensor capable of measuring Cu2+ ions with a linear range from 0.1 to 10 mu M in vitro and in vivo. Using the gold-modified nanopipette sensor with a copper chelating ligand, we evaluated the accumulation ability of the liposomal form of an anticancer Cu-containing complex at three levels of biological organization. First, we detected Cu2+ ions in a single cell model of human breast adenocarcinoma MCF-7 and in murine melanoma B16 cells. The insertion of the nanoelectrode did not result in leakage of the cell membrane. We then evaluated the distribution of the Cu-complex in MCF-7 tumor spheroids and found that the diffusion-limited accumulation was a function of the depth, typical for 3D culture. Finally, we demonstrated the use of the sensor for Cu2+ ion detection in the brain of an APP/PS1 transgenic mouse model of Alzheimer's disease and tumor-bearing mice in response to injection (2 mg kg(-1)) of the liposomal form of the anticancer Cu-containing complex. Enhanced stability and selectivity, as well as distinct copper oxidation peaks, confirmed that the developed sensor is a promising tool for testing various types of biological systems. In summary, this research has demonstrated a minimally invasive electrochemical technique with high temporal resolution that can be used for the study of metabolism of copper or copper-based drugs in vitro and in vivo.

The research is devoted to comparison of the blood vessel structure and the oxygen state of three xenografts: SN-12C, HCT-116 and Colo320. Differences in the vessel formation and the level of oxygenation are revealed by optoacoustic (OA) microscopy and diffuse optical spectroscopy (DOS) respectively. The Colo320 tumor is characterized by the highest values of vessel size and fraction. DOS showed increased content of deoxyhemoglobin that led to reduction of saturation level for Colo320 as compared to other tumors. Immunohistochemical (IHC) analysis for CD31 demonstrates the higher number of vessels in Colo320. The IHC for hypoxia was consistent with DOS results and revealed higher values of the relative hypoxic fraction in Colo320.