Search Results (2,376)

Background: Irradiation (IR) targets cancer cells, but also the tumor microenvironment, including the tumor’s blood vessels. In addition to tumor endothelial cell (TEC) apoptosis, IR can lead to TEC activation, potentially increasing immune cell infiltration. However, the changes underlying the IR-induced activation of endothelial cells (ECs) are poorly understood. This study investigated dose- and time-dependent molecular and functional responses of murine and human EC lines to IR in vitro and TECs in vivo in murine tumor models of colorectal carcinoma. Methods: HUVEC, EA.hy926, and Hulec5a, as well as murine bEND.3, 2H11, and SVEC4-10 EC lines, were irradiated with single doses of 2–10 Gy. EC proliferation and survival after IR were assessed by staining all nuclei (Hoechst 33342) and dead cells (propidium iodide) every 24 h for 5 days using the Cytation 1 Cell Imaging Multi-Mode Reader. RNA sequencing analysis of HUVECs irradiated with 2 Gy and 5 Gy at 24 h and 72 h after IR was conducted, focusing on processes related to EC activation. To validate the RNA sequencing results, immunofluorescence staining for proteins related to EC activation, including Stimulator of Interferon Response cGAMP Interactor 1 (STING), Nuclear factor kappa B (NF-κβ), and Vascular cell adhesion molecule 1 (VCAM-1), was performed. To validate the in vitro results, the response of TEC in vivo was analyzed using publicly available RNA sequencing data of TECs isolated from MC38 colon carcinoma irradiated with a single dose of 15 Gy. Finally, murine CT26 colon carcinoma tumors were immunofluorescently stained for STING and NF-κβ 24 and 48 h after IR with a clinically relevant fractionated regimen of 5 × 5 Gy. Results: Doses of 2, 4, 6, 8, and 10 Gy led to a dose-dependent decrease in proliferation and increased death of ECs. RNA sequencing analysis showed that the effects on the transcriptome of HUVECs were most pronounced 72 h after IR with 5 Gy, with 1014 genes (661 down-regulated and 353 up-regulated) being significantly differentially expressed. Irradiation with 5 Gy resulted in HUVEC activation, with up-regulation of the immune system and extracellular matrix genes, such as STING1 (log₂FC = 0.81) and SELE (log₂FC = 1.09), respectively; and down-regulation of cell cycle markers. Furthermore, IR led to the up-regulation of immune response- and extracellular matrix (ECM)-associated signaling pathways, including NF-κβ signaling and ECM–receptor interaction, which was also observed in the transcriptome of irradiated murine TECs in vivo. This was confirmed at the protein level with higher expressions of the EC activation-associated proteins STING, NF-κβ, and VCAM-1 in irradiated HUVECs and irradiated TECs in vivo. Conclusions: IR induces changes in ECs and TECs, supporting their activation in dose- and time-dependent manners, potentially contributing to the anti-tumor immune response, which may potentially increase the infiltration of immune cells into the tumor and thus, improve the overall efficacy of RT, especially in combination with immune checkpoint inhibitors. Full article

Ionizing radiation can damage DNA, leading to mutations, and is a risk factor for cancer. Based on the assumption that all radiation exposure poses a risk in linear proportion to its dose, ionizing radiation is considered a non-threshold carcinogen. However, most epidemiological studies have had insufficient statistical power to detect excess cancer risks from low-dose radiation exposure. Therefore, research is needed to identify radiation signatures that distinguish radiation-induced cancers from spontaneously developed cancers. In rodent cancer models, interstitial chromosomal deletions of specific tumor-suppressor gene loci are characteristically found in cancers from irradiated animals. In humans, a high frequency of small deletions and chromosome rearrangements, such as large deletions, inversions, and translocations, has also been reported in second cancers that develop in patients who received radiotherapy and in thyroid cancers diagnosed in residents after the Chornobyl accident. These genomic alterations are likely to be generated as a consequence of the processing of radiation-induced DNA double-strand breaks. Particularly, chromosome rearrangements that occur at loci directly linked to tumor formation after ionizing-radiation exposure are potentially useful as biomarkers and as therapeutic targets for radiation-induced cancer. Here we provide an overview of the radiation-induced mutational signatures observed in animal and human cancers. Full article

Background: Stereotactic ablative radiotherapy (SABR) is increasingly used in the treatment of localized and metastatic renal cell carcinoma (RCC), a malignancy traditionally considered radioresistant. Beyond direct cytotoxicity, SABR may promote immunogenic cell death and modulate the tumor immune microenvironment, though the underlying mechanisms remain incompletely understood. Objectives and Methods: This study examined the immunomodulatory effects of two high-dose irradiation regimens (8 Gy and 3 × 8 Gy) in an in vitro model using two RCC cell lines (ACHN, Caki-2) and peripheral blood mononuclear cells (PBMCs) from healthy donors. Results: The 3 × 8 Gy regimen more effectively reduced tumor cell viability and proliferation, particularly in ACHN cells, suggesting differential radiosensitivity. Both regimens induced secretion of IL-6, IL-8, TGF-β, and VEGF, with levels varying by cell line and dose. Caki-2 cells exhibited a cytokine profile consistent with a pro-inflammatory and potentially immunosuppressive phenotype. Conditioned media from irradiated cells were used to stimulate PBMCs, revealing divergent responses. Media from 3 × 8 Gy-irradiated ACHN cells enhanced PBMC proliferation and increased CD8⁺ T cells and CD11c⁺ monocytes, along with IFN-γ, IL-2, and TNF-α secretion, suggesting immunostimulatory effects. Conversely, media from Caki-2 cells had minimal impact on PBMC proliferation and increased TGF-β levels. Conclusions: These results indicate that high-dose irradiation can differentially modulate immune responses in RCC cell lines, depending on tumor intrinsic properties and irradiation regimen. Further in vivo studies are warranted to validate these findings and support development of SABR immunotherapy combinations guided by predictive immune biomarkers. Full article

Stereotactic body radiation therapy (SBRT) for lung tumors near the chest wall often causes significant chest wall pain (CWP), negatively impacting patients’ quality of life. The mechanisms behind SBRT-induced CWP remain unclear and may involve multiple factors. We investigated crosstalk between radiation-activated osteoclasts and sensory neurons, focusing on osteoclast-derived factors in CWP. Using murine pre-osteoclast cell line Raw264.7, we induced differentiation with Receptor Activator of Nuclear Factor kappa-beta Ligand (RANKL), followed by 10 Gy gamma-irradiation. Conditioned media (C.M) from irradiated osteoclasts was used to treat sensory neuronal cultures from mouse dorsal root ganglia. Neuronal cultures were also exposed to 10 Gy radiation, with and without osteoclast co-culture. Osteoclast markers and pain-associated neuropeptides were analyzed using RT-qPCR and histochemical staining. Osteoclasts differentiation and activity were inhibited using osteoprotegerin (OPG) and risedronate. High-dose radiation significantly increased the size of tartrate-resistant-acid-phosphatase (TRAP)-positive osteoclasts (1.36-fold) and activity biomarkers (Ctsk, 1.35-fold, Mmp9, 1.76-fold). Neurons treated with C.M from irradiated osteoclasts showed ~1.5-fold increase in Calca (calcitonin gene-related peptide) and Tac1 (substance P) expression, which was mitigated by osteoclast inhibitors. These findings suggest that radiation enhances osteoclast activity and promotes pain signaling. Osteoclast inhibitors may represent a therapeutic strategy to reduce CWP and improve quality of life. Full article

Lanthanide-doped inorganic luminescent materials have been extensively studied and applied in X-ray detection and imaging, anti-counterfeiting, and optical information storage. However, many reported rare-earth-based luminescent materials show only single-mode optical responses, which limits their applications in complex scenarios. Here, we report a novel Na₃KMg₇(PO₄)₆:Eu phosphor synthesized by a simple high-temperature solid-state method. The multi-color luminescence of Eu²⁺ and Eu³⁺ ions in a single matrix of Na₃KMg₇(PO₄)₆:Eu, known as radio-photoluminescence, is achieved through X-ray-induced ion reduction. It demonstrated a good linear response (R² = 0.9897) and stable signal storage (storage days > 50 days) over a wide range of X-ray doses (maximum dose > 200 Gy). In addition, after X-ray irradiation, this material exhibits photochromic properties ranging from white to brown in a bright field and shows remarkable bleaching and recovery capabilities under 254 nm ultraviolet light or thermal stimulation. This dual-modal luminescent phosphor Na₃KMg₇(PO₄)₆:Eu, which combines photochromism and radio-photoluminescence, presents a dual-mode X-ray detection and imaging strategy and offers a comprehensive and novel solution for applications in anti-counterfeiting and optical information encryption. Full article

Magnetic resonance techniques are powerful, nondestructive, non-invasive tools with broad applications in radiation dosimetry. Electron paramagnetic resonance (EPR) enables direct quantification of dose-dependent radiation-induced paramagnetic defects, while nuclear magnetic resonance (NMR) reflects the influence of such defects through changes in line width and nuclear spin relaxation. To date, these methods have typically been applied independently. Their combined use to probe radiation damage in the same material offers new opportunities for comprehensive characterization and preferred dosimetry techniques. In this work, we apply both EPR and NMR to investigate radiation damage in lithium carbonate (Li₂CO₃). A detailed EPR analysis of γ-irradiated samples shows that the concentration of paramagnetic defects increases with dose, following two distinct linear regimes: 10–100 Gy and 100–1000 Gy. A gradual decay of the EPR signal was observed over 40 days, even under cold storage. In contrast, ⁷Li NMR spectra and spin–lattice relaxation times in Li₂CO₃ exhibit negligible sensitivity to radiation doses up to 1000 Gy, while ¹H NMR results remain inconclusive. Possible mechanisms underlying these contrasting behaviors are discussed. Full article

Ultrahigh dose rate (UHDR) radiotherapy, also known as FLASH radiotherapy (FLASH-RT), has shown potential for increasing tumor control while sparing normal tissue. In parallel, gold nanoparticles (GNPs) have been extensively explored as radiosensitizers due to their high atomic number and ability to enhance the generation of reactive oxygen species (ROS) through water radiolysis. In this study, we investigate the synergistic effects of UHDR electron beams and GNP-mediated radiosensitization using Monte Carlo (MC) simulations based on the Geant4-DNA code. A spherical water phantom with embedded GNPs of varying sizes (5–100 nm) was irradiated using pulsed electron beams (100 keV and 1 MeV) at dose rates of 60, 100, and 150 Gy/s. The chemical yield of ROS near the GNPs was quantified and compared to an equivalent water nanoparticle model, and the yield enhancement factor (YEF) was used to evaluate radiosensitization. Results demonstrated that YEF increased with smaller GNP sizes and at lower UHDR, particularly for 1 MeV electrons. A maximum YEF of 1.25 was observed at 30 nm from the GNP surface for 5 nm particles at 60 Gy/s. The elevated ROS concentration near GNPs under FLASH conditions is expected to intensify DNA damage, especially double-strand breaks, due to increased hydroxyl radical interactions within nanometric distances of critical biomolecular targets. These findings highlight the significance of nanoparticle size and beam parameters in optimizing ROS production for FLASH-RT. The results provide a computational basis for future experimental investigations into the combined use of GNPs and UHDR beams in nanoparticle-enhanced radiotherapy. Full article

Isoegomaketone [(E)-1-(furan-3-yl)-4-methylpent-2-en-1-one; 1] is abundant in the essential oil of Perilla species and exhibits various biological activities, such as anticancer and anti-inflammatory effects. In order to discover compounds with reduced toxicity or enhanced biological activity through structural modification of natural product-derived components, isoegomaketone was irradiated with an electron beam at five different doses, and (±)-8-methoxy-perilla ketone (2) was obtained with the highest yield of 3.8% (w/w) at 80 kGy. Its structure was identified by one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy and high-resolution chemical ionization mass spectrometry. Compound 2 inhibited nitric oxide production and inducible nitric oxide synthase mRNA expression in a dose-dependent manner in lipopolysaccharide-stimulated RAW 264.7 cells. It also dose-dependently suppressed the mRNA expression of pro-inflammatory mediators such as IL-1β, IFN-β, and MCP-1, while having no significant effect on IL-6 mRNA levels. Furthermore, ELISA analysis demonstrated that 2 reduced MCP-1 protein expression but did not affect the protein level of TNF-α or IL-6. This study provides a reference for the structural analysis of compounds related to 2 by presenting NMR data acquired with chloroform-d, and is the first to report the anti-inflammatory properties of 2. Full article

Photobiomodulation (PBM) consists of applying low-level laser light to biological tissues, leading to modulation of cellular functions. PBM has recently gained much attention in the field of regenerative dentistry thanks to its powerful effect on tissue repair and regeneration. Dental pulp mesenchymal stem/stromal cells (DP-MSCs) represent the ideal targets in regenerative dentistry due to their ability to stimulate the regeneration of mineralized and soft tissues and the paracrine factors that they produce. Although there have been several studies evaluating the influence of PBM on DP-MSCs’ regenerative capacity, the results are conflicting, and there are few studies on the influence of PBM on the paracrine factors released by DP-MSCs. Therefore, the aim of this study was to investigate the effect of PBM, using different energy doses of laser irradiation, on the osteogenic capacity of DP-MSCs, focusing on changes in gene expression, mineralizing ability, and release of pro-osteogenic factors. DP-MSCs were irradiated in vitro and differentiated into an osteogenic phenotype. A cell viability assay, alizarin red staining, and TEM analysis were carried out to evaluate the effect of PBM on cell activity, morphology, and mineralization ability. The expression of the main osteogenesis-related markers Runx2, Col1A1, ALP, and BMP was measured to evaluate the influence of PBM on the ability of DP-MSCs to differentiate toward an osteogenic phenotype. The release of IL-6 and IL-8, which are mainly involved in bone remodeling processes, was investigated in the cell medium following PBM irradiation. The results showed a high level of cell viability, suggesting a lack of phototoxicity under the tested conditions. Furthermore, PBM had a significant effect on mineral deposition, IL-6 and IL-8 release, and expression of osteogenic markers. TEM analysis showed intracellular modifications linked mainly to mitochondria, the endoplasmic reticulum, and autophagic vesicles after PBM treatment. These findings demonstrated that the impact of PBM on the osteogenic potential of DP-MSCs is energy dose-dependent, supporting its potential as an effective strategy in regenerative dentistry, particularly for enhancing bone remodeling. Full article

Background and Objectives: Total body irradiation (TBI) remains a cornerstone of conditioning for allogeneic haematopoietic stem-cell transplantation (HSCT). Whereas early research debated the need for irradiation, contemporary investigations focus on optimising dose, fractionation and delivery techniques. Material and Methods: We synthesised six decades of evidence, spanning from single-fraction cobalt treatments to modern helical tomotherapy and intensity-modulated total-marrow/lymphoid irradiation (TMI/TMLI). To complement the literature, we reported our institutional experience on 77 paediatric and adult recipients treated with conventional extended-source-to-skin-distance TBI at the University Hospital Policlinico “G. Rodolico–San Marco” between 2015 and 2025. Results: According to literature data, fractionated myeloablative schedules, typically 12 Gy in 6 fractions, provide superior overall survival and lower rates of severe graft-versus-host disease (GVHD) compared with historical single-dose regimens. Conversely, reduced-intensity protocols of 2–4 Gy broaden HSCT eligibility for older or comorbid patients with acceptable toxicity. Conformal planning reliably decreases mean lung dose without compromising engraftment, and early-phase trials are testing selective escalation to 16–20 Gy or omission of TBI in molecularly favourable cases. With regard to our institutional retrospective series, 92% of patients completed a 12-Gy regimen with only transient grade 1–2 nausea, fatigue or hypotension; all transplanted patients engrafted, and no grade ≥ 3 radiation pneumonitis occurred. Conclusions: Collectively, the published evidence and our experience support TBI as an irreplaceable component of HSCT conditioning and suggest that coupling it with advanced imaging, organ-sparing dosimetry and molecular response monitoring can deliver safer, more personalised therapy in the coming decade. Full article

Ionizing radiation is a well-known environmental stressor capable of generating excessive reactive oxygen species (ROS), leading to oxidative damage in sensitive tissues, including the reproductive system. While oxidative stress is increasingly implicated in male reproductive dysfunction, the long-term effects of low-dose-rate (LDR) radiation on testicular structure and oxidative status remain underexplored. In this study, mice were exposed to continuous LDR radiation (0.39, 1.29, and 3.46 mGy/h) for 21 days to assess testicular histopathology and oxidative status. Although testis weight did not significantly differ among groups, histological analysis revealed basal membrane disruption and reduced spermatogenic cell populations in irradiated groups. Masson’s Trichrome and Sirius Red staining demonstrated dose-dependent collagen deposition, indicating progressive testicular fibrosis. TUNEL assays confirmed increased germ cell apoptosis in the mid- and high-dose-rate groups. ROS levels were significantly elevated only in the highest-dose group, suggesting a threshold-dependent oxidative stress response. These findings indicate that chronic LDR radiation induces testicular damage primarily through apoptosis and fibrosis, with oxidative stress potentially contributing at higher exposure levels. Full article

In this study, the key lithographic performance of PMMA 950K resist was evaluated by exposure to a 30 keV focused gallium (Ga⁺) ion beam. The sensitivity and contrast of PMMA 950K were directly compared with those of electron exposure under identical development conditions. It was found that the sensitivity of PMMA 950K to Ga⁺ ions for 50 nm films reaches a value of about 0.4 μC/cm², which is more than 250 times higher than its sensitivity to electron exposure. A method for evaluating the resist contrast during ion exposure is proposed in this work, taking into account the highly non-uniform dose distribution across the resist depth; it yielded a contrast value of γ = 2.6, which is consistent with the result obtained with electron exposure (γ = 2.8). In addition, a pronounced dependence of the resist sensitivity on the resist thickness was found: with an increase in thickness from 10 nm to 60 nm the sensitivity decreases by an order of magnitude. The obtained results form a reliable methodological basis for characterizing the behavior of polymer resists under ion irradiation and provide valuable recommendations for optimizing lithography with a focused beam of Ga⁺ ions when creating nanostructures for microelectronics, photonics, and quantum technologies. Full article

Background: Hepatocellular carcinoma (HCC) remains a global health challenge with limited therapeutic efficacy. Photodynamic therapy (PDT) using 5,10,15-triethoxycarbonyl P(V) corrole (1-P) shows promise, but its molecular mechanisms and regulatory factors, particularly the role of SIRT1, are poorly understood. Methods: The effects of 1-P combined with red light irradiation (625 nm) on HCC cells (HepG2, PLC/PRF5, MHCC97H) were evaluated via MTT, clonogenic assays, flow cytometry (apoptosis, mitochondrial membrane potential, ROS), and Western blotting (p53, Bax, Bcl-2, cleaved caspase-3, SIRT1). SIRT1-overexpressing cells and xenograft mouse models were used to validate its regulatory role. Results: 1-P with irradiation dose-dependently inhibited cell viability (IC50: 0.965–1.478 μM), suppressed clonogenicity, induced apoptosis (up to 68.8%), reduced mitochondrial membrane potential, and elevated ROS. Mechanistically, 1-P upregulated Bax/p53/cleaved caspase-3 and downregulated Bcl-2/SIRT1. SIRT1 overexpression rescued 1-P-induced apoptosis (30–50% reduction), restored mitochondrial function, and attenuated ROS accumulation. In vivo, 1-P significantly inhibited tumor growth in mice, but SIRT1 overexpression diminished this effect (p < 0.05). Conclusions: 1-P exerts potent photodynamic anticancer effects via mitochondrial dysfunction, oxidative stress, and apoptosis induction. SIRT1 is a critical modulator of 1-P activity, highlighting its potential as a therapeutic target to enhance PDT efficacy in HCC. Full article

Quartz is a widely used mineral in dosimetric and geochronological applications due to its stable luminescence properties under ionizing radiation. This study presents an artificial neural network (ANN)-based approach to predict the optically stimulated luminescence (OSL) decay curves of quartz extracted from Mediterranean beach sand samples in Turkey. Experimental OSL signals were obtained from quartz samples irradiated with beta doses ranging from 0.1 Gy to 1034.9 Gy. The dataset was used to train ANN models with three different learning algorithms: Levenberg–Marquardt (LM), Bayesian Regularization (BR), and Scaled Conjugate Gradient (SCG). Forty-seven decay curves were used for training and three for testing. The ANN models were evaluated based on regression accuracy, training–validation–test performance, and their predictive capability for low, medium, and high doses (1 Gy, 72.4 Gy, 465.7 Gy). The results showed that BR achieved the highest overall regression (R = 0.99994) followed by LM (R = 0.99964) and SCG (R = 0.99820), confirming the superior generalization and fits across all dose ranges. LM performs optimally at low-to-moderate doses, and SCG delivers balanced yet slightly noisier predictions. The proposed ANN-based method offers a robust and effective alternative to conventional kinetic modeling approaches for analyzing OSL decay behavior and holds considerable potential for advancing luminescence-based retrospective dosimetry and OSL dating applications. Full article

In a recent multicenter analysis of 454 patients undergoing post-prostatectomy salvage radiotherapy, the open surgical approach, as opposed to minimally invasive surgery, emerged, unexpectedly, as the strongest predictor of acute gastrointestinal and genitourinary toxicity. Patients treated with laparoscopic or robotic prostatectomy experienced significantly lower rates of ≥grade 2 toxicity compared to those who had undergone open retropubic surgery, irrespective of total dose, treatment margins, or radiation delivery platform. This finding, which to our knowledge has not been previously reported, raises the hypothesis that surgical technique leaves a lasting biological imprint on irradiated tissues. Drawing on current knowledge in radiobiology, cytokine signaling, wound healing, and pelvic dosimetry, we explore potential mechanisms by which open surgery may create a more hypoxic, inflamed, and fibrotic microenvironment, thereby amplifying radiation damage. We further discuss how target volume margins may biologically interact with this tissue state to increase normal tissue exposure. This Perspective aims to provide a conceptual framework for understanding this unexpected association, highlighting its clinical relevance for individualizing margins, counselling high-risk patients, and designing future studies at the interface of surgery and radiation oncology. This paper does not introduce additional patients or statistical models; instead, it offers an in-depth clinical and mechanistic interpretation of previously published ICAROS findings. Full article