Gy Dose Of X-rays Research Articles

Development of tumor-specific liposomes containing quantum dots-photosensitizer conjugate used for radiotherapy

This study aims to develop a multifunctional liposomal radiosensitizer to destroy more tumor cells by using lower radiation doses compared to clinically used 6 MV X-ray doses. To achieve this aim, first Chlorine-e6 (Ce6) was covalently bound to functional groups of outer surfaces of quantum dots (QDs) through EDC/NHS reactions. Then, QDs-Ce6 conjugate loaded, nanosized, PEG-coated, and tumor-specific folic acid-modified immunoliposome dispersions were prepared by film method. Enhanced anti-proliferation activity of free and liposomal conjugate against 4T1 (murine breast cancer) cell lines was investigated at different X-ray doses (5, 10, 15, and 20 Gy). As a result, the best radiosensitizer effect was observed at a 5 Gy X-ray dose and it was found that following the X-ray irradiation, immunoliposome dispersions containing QDs-Ce6 conjugate killed 26.8 ± 1.7% more cancer cells than radiation alone.

Copper uptake in adult rainbow trout irradiated during early life stages and in non-irradiated bystander trout which swam with the irradiated fish

Purpose This investigation forms part of a wider study into the legacy effects of exposure of rainbow trout eggs 38 h after fertilization, eyed eggs, yolk sac larvae (YSL) or first feeders to a single 0.5 Gy X-ray dose, including the induction of a bystander effect, by the irradiated fish, to non-irradiated fish. Fish may be exposed to multiple environmental stressors, including waterborne metals, during their lifespan and, while there are data on how the legacy of early life stage irradiation and bystander effect induction is affected by waterborne aluminum and cadmium, there are no studies into the effects radiation or the radiation induced bystander effect on metal uptake. Therefore the aim of this investigation was to determine if the legacy of early life stage irradiation included an effect on copper uptake by adult fish and by non-irradiated bystander adult trout which swam with the irradiated fish. Methods The four early life stages mentioned above were exposed to a single 0.5 Gy X-ray dose and then maintained, for two years with no further irradiation. At two years old the irradiated fish were allowed to swim, for 2 h with non-irradiated bystander trout (also two years old). After this time copper uptake was determined using 64Cu. Results Copper uptake was increased in adult trout irradiated as eggs at 48 h after fertilization and as first feeders but eyed egg or YSL irradiation had no effect. Copper uptake was also increased in the bystander trout which swam with trout irradiated as eggs at 48 h after fertilization and as eyed eggs but there was no effect on non-irradiated adult trout which swam with trout irradiated as YSL or first feeders. Conclusions When put in context with the proteomic changes observed in these fish we propose the increased copper uptake in adult trout irradiated as eggs at 48 h after fertilization could be part of an anti-tumorigenic response and the increase in copper uptake in adult trout irradiated as first feeders could be part of a potentially protective pro-apoptotic response. Similarly we propose the increase in copper uptake in non-irradiated adult trout, induced by trout irradiated as eggs at 48 h after fertilization or as eyed eggs, was part of the universally anti-tumorigenic nature of the X-ray induced bystander effect in fish. However this was exclusive to embryonic irradiation.

Breakthrough whole body energy-specific and tissue-specific photoneutron dosimetry by novel miniature neutron dosimeter/spectrometer

Breakthrough whole body energy-specific photoneutron (PN) dosimetry was made in/out-of-field in polyethylene phantom organ surface/depths remote from isocenter of 10 × 10 cm2 field prostate cancer therapy in 18 MV X-rays Varian Clinac 2100C medical linear accelerator for PN tissue-specific second primary cancer (PN-SPC) risk estimation. A novel miniature neutron dosimeter/spectrometer with polycarbonate/10B/cadmium inserts was invented and applied. Each dosimeter determines seven tissue-specific dose equivalent (mSv)/Gy X-ray dose at each measurement point providing seven major energy-specific responses for beam thermal, albedo thermal, total thermal, total epithermal, total fast, sum of totals (thermal + epithermal) and sum of totals (thermal + epithermal + fast) PNs dose equivalents. The neutron dosimeter is simple, efficient, and unique with high spatial resolution and provides matrix of energy-specific PN dose equivalent (mSv)/Gy X-ray dose on surface and organ depths for tissue-specific PN-SPC risk estimation. The dosimeter also performs like a “miniature neutron spectrometer” and is unique for other applications in health physics in particular individual neutron dosimetry, medical physics, space flights, science and technology.

Ecdysterone Attenuates the Development of Radiation-Induced Oral Mucositis in Rats at Early Stage.

Oral mucositis is a common adverse reaction of radiotherapy used for head and neck cancers. Our research investigates the therapeutic effect and potential mechanisms of ecdysterone, a compound which was used as a functional food additive, isolated from the root of medicine-food herbs Achyranthes bidentata (Blume), on radiation-induced oral mucositis in rats during the early development stages of mucositis. In this study, male Sprague-Dawley rats received a single 20 Gy X-ray dose to the head and neck after placement of each animal in a specially-constructed 5-mm lead jig. At 24 h postirradiation, ecdysterone was administrated orally. Therapeutic effects of ecdysterone were investigated by observing weight changes and development of mucositis on days 5 and 10 after treatment. Determination of superoxide dismutase and malondialdehyde concentration was performed 5 days after treatment. H&E and leukocyte common antigen staining and TUNEL assays were performed 10 days after treatment. After 10 days of treatment, total protein from the tongue samples was extracted and Western blot analysis was performed to evaluate changes in protein expression. The results of this study showed that ecdysterone prevented the development of radiation-induced oral mucositis in rats during the early stages. Ecdysterone significantly attenuated radiation-induced decrease in cellular superoxide dismutase concentration and increase in malondialdehyde concentration. Ecdysterone was also linked to up-regulation of anti-apoptotic protein Bcl-2 and down-regulation of pro-apoptotic proteins Bax and cleaved caspase-3. In conclusion, these findings suggest that orally administrated ecdysterone alleviates the development of radiation-induced oral mucositis in rats with remarkable anti-oxidant and anti-apoptotic activities at early stages after irradiation.

Y2O3 Nanoparticles and X-ray Radiation-Induced Effects in Melanoma Cells.

The innovative strategy of using nanoparticles in radiotherapy has become an exciting topic due to the possibility of simultaneously improving local efficiency of radiation in tumors and real-time monitoring of the delivered doses. Yttrium oxide (Y2O3) nanoparticles (NPs) are used in material science to prepare phosphors for various applications including X-ray induced photodynamic therapy and in situ nano-dosimetry, but few available reports only addressed the effect induced in cells by combined exposure to different doses of superficial X-ray radiation and nanoparticles. Herein, we analyzed changes induced in melanoma cells by exposure to different doses of X-ray radiation and various concentrations of Y2O3 NPs. By evaluation of cell mitochondrial activity and production of intracellular reactive oxygen species (ROS), we estimated that 2, 4, and 6 Gy X-ray radiation doses are visibly altering the cells by inducing ROS production with increasing the dose while at 6 Gy the mitochondrial activity is also affected. Separately, high-concentrated solutions of 25, 50, and 100 µg/mL Y2O3 NPs were also found to affect the cells by inducing ROS production with the increase of concentration. Additionally, the colony-forming units assay evidenced a rather synergic effect of NPs and radiation. By adding the NPs to cells before irradiation, a decrease of the number of proliferating cell colonies was observed with increase of X-ray dose. DNA damage was evidenced by quantifying the γ-H2AX foci for cells treated with Y2O3 NPs and exposed to superficial X-ray radiation. Proteomic profile confirmed that a combined effect of 50 µg/mL Y2O3 NPs and 6 Gy X-ray dose induced mitochondria alterations and DNA changes in melanoma cells.

Role of blood derived cell fractions, temperature and sample transport on gene expression-based biological dosimetry

Purpose For triage purposes following a nuclear accident or a terrorist event, gene expression biomarkers in blood have been demonstrated to be good bioindicators of ionizing radiation (IR) exposure and can be used to assess the dose received by exposed individuals. Many IR-sensitive genes are regulated by the DNA damage response pathway, and modulators of this pathway could potentially affect their expression level and therefore alter accurate dose estimations. In the present study, we addressed the potential influence of temperature, sample transport conditions and the blood cell fraction analyzed on the transcriptional response of the following radiation-responsive genes: FDXR, CCNG1, MDM2, PHPT1, APOBEC3H, DDB2, SESN1, P21, PUMA, and GADD45. Materials and Methods Whole blood from healthy donors was exposed to a 2 Gy X-ray dose with a dose rate of 0.5 Gy/min (output 13 mA, 250 kV peak, 0.2 mA) and incubated for 24 h at either 37, 22, or 4 °C. For mimicking the effect of transport conditions at different temperatures, samples incubated at 37 °C for 24 h were kept at 37, 22 or 4 °C for another 24 h. Comparisons of biomarker responses to IR between white blood cells (WBCs), peripheral blood mononuclear cells (PBMCs) and whole blood were carried out after a 2 Gy X-ray exposure and incubation at 37 °C for 24 hours. Results Hypothermic conditions (22 or 4 °C) following irradiation drastically inhibited transcriptional responses to IR exposure. However, sample shipment at different temperatures did not affect gene expression level except for SESN1. The transcriptional response to IR of specific genes depended on the cell fraction used, apart from FDXR, CCNG1, and SESN1. Conclusion In conclusion, temperature during the incubation period and cell fraction but not the storing conditions during transport can influence the transcriptional response of specific genes. However, FDXR and CCNG1 showed a consistent response under all the different conditions tested demonstrating their reliability as individual biological dosimetry biomarkers.

Immunophenotyping Reveals No Significant Perturbation to PBMC Subsets When Co-cultured With Colorectal Adenocarcinoma Caco-2 Cells Exposed to X-Rays.

In vitro co-culture models between tumor cells and peripheral blood mononuclear cells (PBMCs) allow studying the interplay between these cell populations, potentially gaining insight into the in vivo response of the immune system to the presence of the tumor, as well as to possible other agents as radiation used for therapeutic purposes. However, great care is needed in the experimental optimization of models and choice of conditions, as some setups might offer a limited possibility to capture subtle immune perturbations. A co-culture model of PBMCs from healthy donors and colorectal adenocarcinoma Caco-2 cells was successfully adopted in a previous work to measure effects on Caco-2 and modulation of signaling when these latter are irradiated. We here tested if the same experimental setting allows to measure perturbations to the main PBMC subsets: we performed immunophenotyping by means of flow cytometry and quantified helper and cytotoxic T cells, NK cells, and B cells, when PBMCs are cultured alone (control), in presence of non-irradiated Caco-2 cells or when these latter are exposed to a 10 Gy X-ray dose from a conventional radiotherapy accelerator. To measure a baseline response in all experimental conditions, PBMCs were not further stimulated, but only followed in their time-evolution up to 72 h post-irradiation of Caco-2 and assembly of the co-culture. In this time interval PBMCs maintain a high viability (measured via the MTT assay). Caco-2 viability (MTT) is slightly affected by the presence of PBMCs and by the high radiation dose, confirming their radioresistance. Immunophenotyping results indicate a large inter-individual variability for different population subsets already at the control level. We analyzed relative population changes and we detected only a small but significant perturbation to cytotoxic T cells. We conclude that this model, as it is, is not adequate for the measurements of subtler immune perturbations (if any, not washed-out by inter-individual differences). For this purpose, the model needs to be modified and further optimized e.g., including a pre-treatment strategy for PBMCs. We also performed a pooled analysis of all experimental observations with principal component analysis, suggesting the potential of this tool to identify subpopulations of similarly-responding donors.

Radioactivity induced in new-generation cardiac implantable electronic devices during high-energy X-ray irradiation

This study provides the first insight into the problem of the induced radioactivity of the construction materials of the new-generation cardiac implantable electronic devices (CIEDs). Its aim was to identify nuclear reactions and the resulting radioisotopes induced in the CIEDs by high-energy X-ray therapeutic beams generated by medical linear accelerators. The presented results allow to verify the rightness of choice of materials for investigated CIEDs. Such analysis is currently available only for the older types of the CIEDs, but not for those of the new generation. Gamma spectrometry measurements have been performed using a high-purity germanium detector (HPGe). The identification and activities of the generated radioisotopes were obtained from the measured spectra of gamma - rays from decays of the produced unstable radioisotopes. 21 radioisotopes originating from 24 nuclear reactions were identified. For all considered models of CIEDs the highest activities are from the tin isomer 117mSn. The induced activities were relatively small, not exceeding 3.1 Bq per a 1 Gy X-ray dose to a target volume.

Rosiglitazone Protects Endothelial Cells From Irradiation-Induced Mitochondrial Dysfunction.

Background and PurposeUp to 50–60% of all cancer patients receive radiotherapy as part of their treatment strategy. However, the mechanisms accounting for increased vascular risks after irradiation are not completely understood. Mitochondrial dysfunction has been identified as a potential cause of radiation-induced atherosclerosis.Materials and MethodsAssays for apoptosis, cellular metabolism, mitochondrial DNA content, functionality and morphology were used to compare the response of endothelial cells to a single 2 Gy dose of X-rays under basal conditions or after pharmacological treatments that either reduced (EtBr) or increased (rosiglitazone) mitochondrial content.ResultsExposure to ionizing radiation caused a persistent reduction in mitochondrial content of endothelial cells. Pharmacological reduction of mitochondrial DNA content rendered endothelial cells more vulnerable to radiation-induced apoptosis, whereas rosiglitazone treatment increased oxidative metabolism and redox state and decreased the levels of apoptosis after irradiation.ConclusionPre-existing mitochondrial damage sensitizes endothelial cells to ionizing radiation-induced mitochondrial dysfunction. Rosiglitazone protects endothelial cells from the detrimental effects of radiation exposure on mitochondrial metabolism and oxidative stress. Thus, our findings indicate that rosiglitazone may have potential value as prophylactic for radiation-induced atherosclerosis.

Impact of the PrC-210 Radioprotector Molecule on Cancer Deaths in p53-Deficient Mice.

Radiation-induced cancer is an ongoing and significant problem, with sources that include clinics worldwide in which 3.1 billion radiology exams are performed each year, as well as a variety of other scenarios such as space travel and nuclear cleanup. These radiation exposures are typically anticipated, and the exposure is typically well below 1 Gy. When radiation-induced (actually ROS-induced) DNA mutation is prevented, then so too are downstream radiation-induced cancers. Currently, there is no protection available against the effects of such <1 Gy radiation exposures. In this study, we address whether the new PrC-210 ROS-scavenger is effective in protecting p53-deficient (p53-/-) mice against X-ray-induced accelerated tumor mortality; this is the most sensitive radiation tumorigenesis model currently known. Six-day-old p53-/- pups received a single intraperitoneal PrC-210 dose [0.5 maximum tolerated dose (MTD)] or vehicle, and 25 min later, pups received 4.0 Gy X-ray irradiation. At 5 min postirradiation, blood was collected to quantify white blood cell c-H2AX foci. Over the next 250 days, tumor-associated deaths were recorded. Findings revealed that when administered 25 min before 4 Gy X-ray irradiation, PrC-210 reduced DNA damage (c-H2AX foci) by 40%, and in a notable coincidence, caused a 40% shift in tumor latency/incidence, and the 0.5 MTD PrC210 dose had no discernible toxicities in these p53-/- mice. Essentially, the moles of PrC-210 thiol within a single 0.5 MTD PrC-210 dose suppressed the moles of ROS generated by 40% of the 4 Gy X-ray dose administered to p53-/- pups, and in doing so, eliminated the lifetime leukemia/lymphoma risk normally residing "downstream" of that 40% of the 4 Gy dose. In conclusion: 1. PrC-210 is readily tolerated by the 6-day-old p53-/- mice, with no discernible lifetime toxicities; 2. PrC-210 does not cause the nausea, emesis or hypotension that preclude clinical use of earlier aminothiols; and 3. PrC-210 significantly increased survival after 4 Gy irradiation in the p53-/- mouse model.

Lowering iron level protects against bone loss in focally irradiated and contralateral femurs through distinct mechanisms.

Radiation therapy leads to increased risk of late-onset fragility and bone fracture due to the loss of bone mass. On the other hand, iron overloading causes osteoporosis by enhancing bone resorption. It has been shown that total body irradiation increases iron level, but whether the systemic bone loss is related to the changes in iron level and hepcidin regulation following bone irradiation remains unknown. To investigate the potential link between them, we first created an animal model of radiation-induced systemic bone loss by targeting the mid-shaft femur with a single 2 Gy dose of X-rays. We found that mid-shaft femur focal irradiation led to structural deterioration in the distal region of the trabecular bone with increased osteoclasts surface and expressions of bone resorption markers in both irradiated and contralateral femurs relative to non-irradiated controls. Following irradiation, reduced hepcidin activity of the liver contributed to elevated iron levels in the serum and liver. By injecting hepcidin or deferoxamine (an iron chelator) to reduce iron level, deterioration of trabecular bone microarchitecture in irradiated mice was abrogated. The ability of iron chelation to inhibit radiation-induced osteoclast differentiation was observed in vitro as well. We further showed that ionizing radiation (IR) directly stimulated osteoclast differentiation and bone resorption in bone marrow cells isolated not from contralateral femurs but from directly irradiated femurs. These results suggest that increased iron levels after focal radiation is at least one of the main reasons for systemic bone loss. Furthermore, bone loss in directly irradiated bones is not only due to the elevated iron level, but also from increased osteoclast differentiation. In contrast, the bone loss in the contralateral femurs is mainly due to the elevated iron level induced by IR alone. These novel findings provide proof-of-principle evidence for the use of iron chelation or hepcidin as therapeutic treatments for IR-induced osteoporosis.

Irradiation of rainbow trout at early life stages results in a proteomic legacy in adult gills. Part A; proteomic responses in the irradiated fish and in non-irradiated bystander fish

Exposure to a single 0.5 Gy X-ray dose of eggs at 48 h after fertilisation (48 h egg), eyed eggs, yolk sac larvae (YSL) and first feeders induces a legacy effect in adult rainbow trout. This includes the transmission of a bystander effect to non-irradiated adult trout which had swam with the irradiated fish. The aim of this study was to investigate this legacy by analysing the gill proteome of these irradiated and bystander fish. Irradiation at all of the early life stages resulted in changes to proteins which play a key role in development but are also known to be anti-tumorigenic and anti-oxidant: upregulation of haemoglobin subunit beta (48 h egg), haemoglobin, serum albumin 1 precursor (eyed eggs), clathrin heavy chain 1 isoform X10 (eyed eggs and first feeders), and actin-related protein 2/3 complex subunit 4 (first feeders), downregulation of pyruvate dehydrogenase, histone 1 (48 h egg), triosephosphate isomerase (TPI), collagen alpha-1(1) chain like proteins (YSL), pyruvate kinase PKM-like protein (YSL and first feeders), ubiquitin-40S ribosomal proteins S27 and eukaryotic translation initiation factor 4 A isoform 1B (first feeders). However irradiation of YSL and first feeders (post hatching early life stages) also induced proteomic changes which have a complex relationship with tumorigenesis or cancer progression; downregulation of alpha-1-antiprotease-like protein precursor, vigilin isoform X2 and nucleoside diphosphate kinase (YSL) and upregulation of hyperosmotic glycine rich protein (first feeders). In bystander fish some proteomic changes were similar to those induced by irradiation: upregulation of haemoglobin subunit beta (48 h egg), haemoglobin (eyed eggs), actin-related protein 2/3 complex subunit 4, hyperosmotic glycine rich protein (first feeders), and downregulation of alpha-1-antiprotease-like protein, vigilin isoform X2, nucleoside diphosphate kinase (YSL), pyruvate kinase PKM-like protein and ubiquitin-40S ribosomal protein S27a-like (first feeders). Other proteomic changes were unique to bystander fish; downregulation of TPI, ubiquitin-40S ribosomal protein S2 (eyed egg), cofilin-2, cold-inducible RNA-binding protein B-like isoform X3 (YSL) and superoxide dismutase (first feeder), and upregulation of haemoglobin subunit alpha, collagen 1a1 precursor, apolipoprotein A-1-1 and A-1–2 precursor (first feeders). These bystander effect proteomic changes have been shown to be overwhelmingly anti-tumorigenic or protective of the fish gill.

Biological Entanglement-Like Effect After Communication of Fish Prior to X-Ray Exposure.

The phenomenon by which irradiated organisms including cells in vitro communicate with unirradiated neighbors is well established in biology as the radiation-induced bystander effect (RIBE). Generally, the purpose of this communication is thought to be protective and adaptive, reflecting a highly conserved evolutionary mechanism enabling rapid adjustment to stressors in the environment. Stressors known to induce the effect were recently shown to include chemicals and even pathological agents. The mechanism is unknown but our group has evidence that physical signals such as biophotons acting on cellular photoreceptors may be implicated. This raises the question of whether quantum biological processes may occur as have been demonstrated in plant photosynthesis. To test this hypothesis, we decided to see whether any form of entanglement was operational in the system. Fish from 2 completely separate locations were allowed to meet for 2 hours either before or after which fish from 1 location only (group A fish) were irradiated. The results confirm RIBE signal production in both skin and gill of fish, meeting both before and after irradiation of group A fish. The proteomic analysis revealed that direct irradiation resulted in pro-tumorigenic proteomic responses in rainbow trout. However, communication from these irradiated fish, both before and after they had been exposed to a 0.5 Gy X-ray dose, resulted in largely beneficial proteomic responses in completely nonirradiated trout. The results suggest that some form of anticipation of a stressor may occur leading to a preconditioning effect or temporally displaced awareness after the fish become entangled.

Differential Impact of Single-Dose Fe Ion and X-Ray Irradiation on Endothelial Cell Transcriptomic and Proteomic Responses.

Background and Purpose: Radiotherapy is an essential tool for cancer treatment. In order to spare normal tissues and to reduce the risk of normal tissue complications, particle therapy is a method of choice. Although a large part of healthy tissues can be spared due to improved depth dose characteristics, little is known about the biological and molecular mechanisms altered after particle irradiation in healthy tissues. Elucidation of these effects is also required in the context of long term space flights, as particle radiation is the main contributor to the radiation effects observed in space. Endothelial cells (EC), forming the inner layer of all vascular structures, are especially sensitive to irradiation and, if damaged, contribute to radiation-induced cardiovascular disease.Materials and Methods: Transcriptomics, proteomics and cytokine analyses were used to compare the response of ECs irradiated or not with a single 2 Gy dose of X-rays or Fe ions measured one and 7 days post-irradiation. To support the observed inflammatory effects, monocyte adhesion on ECs was also assessed.Results: Experimental data indicate time- and radiation quality-dependent changes of the EC response to irradiation. The irradiation impact was more pronounced and longer lasting for Fe ions than for X-rays. Both radiation qualities decreased the expression of genes involved in cell-cell adhesion and enhanced the expression of proteins involved in caveolar mediated endocytosis signaling. Endothelial inflammation and adhesiveness were increased with X-rays, but decreased after Fe ion exposure.Conclusions: Fe ions induce pro-atherosclerotic processes in ECs that are different in nature and kinetics than those induced by X-rays, highlighting radiation quality-dependent differences which can be linked to the induction and progression of cardiovascular diseases (CVD). Our findings give a better understanding of the underlying processes triggered by particle irradiation in ECs, a crucial aspect for the development of protective measures for cancer patients undergoing particle therapy and for astronauts in space.

Comparative analysis of the effects of a sphingosine kinase inhibitor to temozolomide and radiation treatment on glioblastoma cell lines

ABSTRACTGlioblastoma multiforme (GBM) exhibits high resistance to the standard treatment of temozolomide (TMZ) combined with radiotherapy, due to its remarkable cell heterogeneity. Accordingly, there is a need to target alternative molecules enhancing specific GBM autocrine or paracrine mechanisms and amplifying the effect of standard treatment. Sphingosine 1-phosphate (S1P) is such a lipid target molecule with an important role in cell invasion and proliferation. Sphingosine kinase inhibitors (SKI) prevent S1P formation and induce increased production of reactive oxygen species (ROS), which may potentiate radiation cytotoxicity. We analyzed the effect of SKI singular versus combined treatments with TMZ and radiation on 2 human GBM cell lines characterized by a lack of MGMT expression and low or high expression of the anti-oxidant enzyme, glutathione peroxidase 1 (GPx1). Effects were drug concentration-, cell line-dependent and partly ROS-mediated. Clonogenic survival assay demonstrates that SKI was more effective than TMZ in increasing the sensitivity of U87 cells, which express low GPx1 amount, to a 2 Gy X-ray dose. Addition of both SKI and TMZ drastically decreased U87 cells survival compared with the combination temozolomide/radiation. SKI less effectively than TMZ sensitized LN229 cells to the 2 Gy X-ray dose. Its combination to TMZ in absence of irradiation was as efficient as TMZ combination with X-ray. We provide first evidence for SKI as an alternative or complementary treatment to TMZ, and for efficient combinations of low doses of drugs and X-ray. These may help as novel bi-modal and tri-modal therapies to contend with GBM heterogeneity.

Induction of Non-Targeted Stress Responses in Mammary Tissues by Heavy Ions.

PurposeSide effects related to radiation exposures are based primarily on the assumption that the detrimental effects of radiation occur in directly irradiated cells. However, several studies have reported over the years of radiation-induced non-targeted/ abscopal effects in vivo that challenge this paradigm. There is evidence that Cyclooxygenase-2 (COX2) plays an important role in modulating non-targeted effects, including DNA damages in vitro and mutagenesis in vivo. While most reports on radiation-induced non-targeted response utilize x-rays, there is little information available for heavy ions.Methods and MaterialsAdult female transgenic gpt delta mice were exposed to an equitoxic dose of either carbon or argon particles using the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS) in Japan. The mice were stratified into 4 groups of 5 animals each: Control; animals irradiated under full shielding (Sham-irradiated); animals receiving whole body irradiation (WBIR); and animals receiving partial body irradiation (PBIR) to the lower abdomen with a 1 x 1 cm2 field. The doses used in the carbon ion group (4.5 Gy) and in argon particle group (1.5 Gy) have a relative biological effectiveness equivalent to a 5 Gy dose of x-rays. 24 hours after irradiation, breast tissues in and out of the irradiated field were harvested for analysis. Induction of COX2, 8-hydroxydeoxyguanosine (8-OHdG), phosphorylated histone H2AX (γ-H2AX), and apoptosis-related cysteine protease-3 (Caspase-3) antibodies were examined in the four categories of breast tissues using immunohistochemical techniques. Analysis was performed by measuring the intensity of more than 20 individual microscopic fields and comparing the relative fold difference.ResultsIn the carbon ion group, the relative fold increase in COX2 expression was 1.01 in sham-irradiated group (p > 0.05), 3.07 in PBIR (p < 0.05) and 2.50 in WBIR (p < 0.05), respectively, when compared with controls. The relative fold increase in 8-OHdG expression was 1.29 in sham-irradiated (p > 0.05), 11.31 in PBIR (p < 0.05) and 11.79 in WBIR (p < 0.05), respectively, when compared with controls. A similar increase in γ-H2AX expression was found in that, compared to controls, the increase was 1.41 fold in sham-irradiated (p > 0.05), 8.41 in PBIR (p < 0.05) and 10.59 in WBIR (p < 0.05). Results for the argon particle therapy group showed a similar magnitude of changes in the various biological endpoints examined. There was no statistical significance observed in Caspase-3 expression among the 4 groups.ConclusionsOur data show that both carbon and argon ions induced non-targeted, out of field induction of COX2 and DNA damages in breast tissues. These effects may pose new challenges to evaluate the risks associated with radiation exposure and understanding radiation-induced side effects.

Tissue-specific effects of acute aluminium exposure on the radiation-induced bystander effect in rainbow trout (Oncorhynchus mykiss, Walbaum)

Purpose: To investigate if aluminium (Al) modifies the rainbow trout response to radiation exposure and/or the induction of a radiation-induced bystander effect.Methods: Rainbow trout were exposed to 100 or 200 μg l−1 Al (for 3 h), a 0.5 Gy X-ray dose or Al followed immediately by irradiation. The exposed fish were then swum with completely untreated bystander fish. A human reporter cell clonogenic assay was used to determine whether Al exposure modified the effects of irradiation on the skin and gills from directly exposed fish and also the radiation-induced bystander effect in untreated fish.Results: Al exposure did not modify the response to direct irradiation by the skin, or the gill. Al did not modify the bystander effect in the skin. However Al did modify the bystander effect in the gill. Gills of bystander fish swum with fish exposed to 200 μg l−1 Al, followed by irradiation, caused a greater reduction in HPV-G cell survival than was caused by irradiation only. Interestingly Al exposure only also caused a bystander effect (reduced HPV-G survival) in the gill.Conclusion: This study shows that, in a multiple stressor scenario, the communication of radiation-induced stress signals is modified on a tissue-specific basis by acute Al exposure. Aside from the implications this has for radiological protection this response may also have potential for environmental monitoring where detection of the bystander effect could act as an indicator of radiation exposure when direct exposure responses are not evident.

Irradiación subletal de fibroblastos murinos 3T3 con rayos X para su utilización como capa celular alimentadora

Keratinocytes, the main cells of the epidermis, require mitotically inactive but live feeder-layer cells for their survival and proliferation. We evaluated four X-ray irradiation doses on 3T3 murine fibroblasts for feeder-layer production. Each dose effect was evaluated by cell counting and cellular viability determination (MTT), cell adhesion (plating efficiency) and cell migration (scratch wound healing). Mitotic arrest was suggested by nuclear staining (GIEMSA). We determined that an 80 Gy X-ray dose generated enough cell damage to cause mitotic arrest yet keeping metabolically active cells up to 25 days.

Abstract A57: Differential tumor cell expression of VEGF isoforms impacts on the tumor microenvironment, metastasis and radiation response in a mouse fibrosarcoma model

Abstract We aimed to determine the influence of differential tumor cell expression of vascular endothelial growth factor A (VEGF) isoforms on lung metastasis and response to radiotherapy. We hypothesized that vascular and other adaptations of the tumor microenvironment, in response to tumor cell expression of individual VEGF isoforms, would impact on tumor progression and treatment response. Mouse fibrosarcoma cells that exclusively express either VEGF120, 164 or 188 (fs120, fs164 and fs188 cells respectively) and cells expressing all three isoforms (fsWT) were grown as sub-cutaneous implants in SCID mice. Tumor sections were stained for vascularity (CD31), oxygenation status (pimonidazole protein adducts), activated fibroblasts/pericytes (FAPalpha/alpha-sma), necrosis (H&amp;E), apoptosis (TUNEL) and extra-cellular matrix proteins (collagen-1, laminin, fibronectin). Interstitial fluid pressure (IFP) was measured by the ‘wick-in-needle’ technique. Parallel single VEGF isoform-expressing cell lines were generated to stably express luciferase2 and mStrawberry (LS) for analysis of lung metastasis from sub-cutaneous implants. Luminescence was measured in lung tissue lysates, using an IVIS Lumina II optical imaging system. Sub-cutaneous tumors were irradiated with a single or fractionated 20 Gy dose of X-rays and tumor volume response measured. All tumors were well-vascularized but IFP was lower in untreated fs188 tumors than in fs120 tumors, consistent with a lower vascular permeability, as previously reported. Fs188 tumors were also significantly less hypoxic (P &amp;lt; 0.05) than fs120 tumors (approximately 20 versus 30% pimonidazole staining). Perivascular alpha-SMA was most prevalent in fs188 and fsWT tumors. FAPalpha was lowest in fs120 tumours. Lungs from fs120-LS and fs164-LS but not fs188-LS and fsWT-LS tumor-bearing mice were significantly more luminescent than control lungs (910 ± 283 and 1107 ± 401 versus 8 ± 3 luminescence units respectively). Laminin staining was significantly greater in the more metastatic tumor types (fs120 and fs164) but no other matrix protein showed any correlation. Fs188 tumors were significantly more sensitive to both single and fractionated radiotherapy (growth and necrosis end-points) than fs120 tumors, despite similar radio-sensitivities of the cells irradiated in vitro. However, TUNEL staining in CD31+ cells was greater in fs120 tumors than in fs188 tumors, suggesting that fs120-associated vasculature was more radio-sensitive than fs188-associated vasculature. Results showed that tumor cell expression of individual VEGF isoforms had a profound effect on the tumor microenvironment. The more metastatic fs120 tumors had relatively high IFP and hypoxia, factors known to influence tumor progression. Less pericyte investiture in fs120 and fs164 tumors could also facilitate tumor cell escape into the circulation for these more metastatic types, which may also relate to high levels of laminin in the extra-cellular matrix. The radio-sensitivity of fs188 tumors is most likely explained by relatively low hypoxia, as oxygen is a classic radio-sensitizer. The fact that blood vessels in the fs120 tumors were actually more sensitive that those in fs188 tumors suggests that the response of blood vessels has only a minor influence on the overall tumor response to radio-therapy. These results suggest the potential for differential VEGF isoform expression (or down-stream consequences of expression) as prognostic and predictive tumor bio-markers. This work was supported by a Programme Grant from Cancer Research UK. Citation Format: William R. English, Sarah Jane Lunt, Matthew Fisher, Jack E. Hurrell, Diane V. Lefley, Debayan Mukherjee, Rachel Daniel, Scott K. Lyons, Chryso Kanthou, Gillian M. Tozer. Differential tumor cell expression of VEGF isoforms impacts on the tumor microenvironment, metastasis and radiation response in a mouse fibrosarcoma model. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr A57. doi:10.1158/1538-7445.CHTME14-A57

X-ray dose delivered during a longitudinal micro-CT study has no adverse effect on cardiac and pulmonary tissue in C57BL/6 mice

Micro-computed tomography (micro-CT) offers numerous advantages for small animal imaging, including the ability to monitor the same animals throughout a longitudinal study. However, concerns are often raised regarding the effects of X-ray dose accumulated over the course of the experiment. To scan C57BL/6 mice multiple times per week for 6 weeks, in order to determine the effect of the cumulative dose on pulmonary and cardiac tissue at the end of the study. C57BL/6 male mice were split into two groups (irradiated group = 10, control group = 10). The irradiated group was scanned (80 kVp/50 mA) three times weekly for 6 weeks, resulting in a weekly dose of 0.84 Gy, and a total study dose of 5.04 Gy. The control group was scanned on the final week. Scans from week 6 were reconstructed and the lungs and heart were analyzed. Overall, there was no significant difference in lung volume or lung density or in left ventricular volume or ejection fraction between the control group and the irradiated group. Histological samples taken from excised lung and myocardial tissue also showed no evidence of inflammation or fibrosis in the irradiated group. This study demonstrated that a 5 Gy X-ray dose accumulated over 6 weeks during a longitudinal micro-CT study had no significant effects on the pulmonary and myocardial tissue of C57BL/6 mice. As a result, the many advantages of micro-CT imaging, including rapid acquisition of high-resolution, isotropic images in free-breathing mice, can be taken advantage of in longitudinal studies without concern for negative dose-related effects.