Radiation-induced Death Research Articles

Models of Patient Derived Hematopoietic Stem Cell Xenografts for Assessing Individual Human Radiosensitivity

There are different approaches to assessing the human individual radiosensitivity. In this study, individual radiosensitivity was assessed in terms of survival and recovery of human hematopoietic stem cells (HSC) after acute gamma irradiation of humanized mice. Immunodeficient NOD SCID mice were transplanted with cord blood HSC intravenously, peripheral or umbilical cord blood HSC intraosseously. The estimated D0 value for human HSCs was 1.19 Gy (95٪ CI 0.90 to 1.74), 0.99 Gy (95٪ CI 0.87 to 1.15), and 0.93 Gy (95٪ CI 0.61 to 1.91) for the three methods of obtaining humanized mice, respectively. For all three methods of mouse humanization, statistically similar models that describe the dependence of HSC survival on the acute gamma irradiation dose in the range of 0.5—1.5 Gy were obtained. Thus, intraosseous administration of peripheral blood HSCs to immunodeficient mice can be effectively used to assess the response of human HSCs to radiation exposure. Comparison of the HSC number (CD34+ cells) and their descendants (CD45+ cells) in non-irradiated and irradiated mice humanized with cells from the same donor on days 3 and 14 after irradiation makes it possible to evaluate the processes of radiation-induced death and recovery of HSCs. A coefficient calculated as the ratio of the proportion of HSCs among all human cells in the bone marrow of humanized mice on the 14th day to the proportion of HSCs on the 3rd day after irradiation was proposed to assess the response to radiation exposure. This coefficient had an inverse linear dependence on the radiation dose, differed in mice with increased and normal radiosensitivity, and increased with the use of the radioprotector cysteamine in humanized mice. We propose to use this coefficient for a comparative assessment of human radiosensitivity.

Significant Reduction of Radiation-Induced Death in Mice Treated with PrC-210 and G-CSF after Irradiation.

The search for single or combined radiation countermeasures that mitigate the development of Acute Radiation Syndrome (ARS) after radiation exposure remains a prominent goal of the U.S. government. This study was undertaken to determine whether PrC-210 and G-CSF, when administered 24-48 h postirradiation, would confer an additive or synergistic survival benefit and mitigate ARS in mice that had received an otherwise 96% lethal radiation dose. Our results show that optimum systemic doses of PrC-210 and G-CSF, when administered 24 h or later after a 96% lethal dose of whole-body irradiation, conferred: 1. strong individual survival benefits (PrC-210 44%, P = 0.003), (G-CSF 48%, P = 0.0002), 2. a profound combined 85% survival benefit (P < 0.0001) when administered together, and on day 14 postirradiation, 3. peripheral white blood cell/lymphocyte counts equal to unirradiated controls, 4. dense bone marrow cell density (>65% of unirradiated controls), 5. jejunal villi density that equaled 90% of unirradiated controls, and 6. spleen weights that equaled 93% of unirradiated controls. Our results show that PrC-210 and G-CSF given together 24 h after irradiation confer strong additive efficacy by protecting the immune system, and enabling recovery of the bone marrow, and they work synergistically to enable recovery of peripheral white blood cells in circulating blood.

MLKL regulates radiation-induced death in breast cancer cells: an interplay between apoptotic and necroptotic signals.

Resistance to caspase-dependent apoptosis is often responsible for treatments failure in cancer. Necroptosis is a type of programmed necrosis that occurs under caspase-deficient conditions that could overcome apoptosis resistance. Our purpose was to investigate the interrelationship between apoptotic and necroptotic death pathways and their influence on the response of breast cancer cells to radiotherapy in vitro. Human BC cell lines MCF-7 and MDA-MB-231 were treated with ionizing radiation, and then several markers of apoptosis, necroptosis, and survival were assessed in the presence and absence of necroptosis inhibition. MLKL knockdown was achieved by siRNA transfection. Our main findings emphasize the role of necroptosis in cellular response to radiation represented in the dose- and time-dependent elevated expression of necroptotic markers RIPK1, RIPK3, and MLKL. Knockdown of necroptotic marker MLKL by siRNA led to a significant elevation in MDA-MB-231 and MCF-7 survival with a dose modifying factor (DMF) of 1.23 and 1.61, respectively. Apoptotic markers Caspase 8 and TRADD showed transitory or delayed upregulation, indicating that apoptosis was not the main mechanism by which cells respond to radiation exposure. Apoptotic markers also showed a significant elevation following MLKL knockdown, suggesting its role either as a secondary or death alternative pathway. The result of our study emphasizes the critical role of the necroptotic pathway in regulating breast cancer cells responses to radiotherapy and suggests a promising utilization of its key modulator, MLKL, as a treatment strategy to improve the response to radiotherapy.

Comparative Study of Biosynthesizing Selenium Nanoparticles by Gum Arabic and Poly Anionic Cellulose to Prevent Radiation-Induced Death in Chinese Hamster Ovary (CHO) Cells

Purpose: In premenopausal women, abdominopelvic radiotherapy may have a direct and profound effect on ovarian function. Stabilized selenium Nanoparticles (NPs) with some natural materials have been demonstrated to have high antioxidant activity and reduce radiation damage as a radioprotector. This study was done to compare the ability for the biosynthesis of selenium NPs by Gum Arabic (Se-GA) and Polyanionic Cellulose (Se-PAC) in the protection of Chinese Hamster Ovary (CHO) cells against radiation damage.&#x0D; Materials and Methods: First, Selenium Nanoparticles (SeNPs) were synthesized in the presence of GA and PAC. Then, CHO cells were cultured in-vitro and were randomly divided into six groups in different concentrations of Se-GA and Se-PAC to measure the biocompatibility of NPs. Finally, cells were treated with NPs and radiation (6MV, 2Gy), and the percentage of cell survival was determined by MTT assay. Both NPs with an average size of 20-30 nm and an absorption absorbance peak at about 300 nm using Ultraviolet-Visible (UV–Vis) spectroscopy.&#x0D; Results: According to the parametric t-test analysis, Se-GA nanoparticles with a concentration higher than 0.4 ppm significantly increased the radioprotective effect on CHO cells compared to the control group (P&lt;0.05). However, Se-PAC showed no significant increase in radioprotection in contrast to the control group (P&gt;0.05).&#x0D; Conclusion: Se-GA nanoparticles have antioxidant properties, and the radiation protection properties of Se-GA nanoparticles are significantly higher than control. Consequently, Se-GA nanoparticles showed promising results and may be able to play the role of a radioprotector.

Photoprotective effect of topical treatment with Lopezia racemosa extract against deleterious UVB irradiation effects in the skin of hairless mice.

Lopezia racemosa is known as a "mosquito flower or perlilla." It is commonly found in corn crops. In traditional Mexican medicine, this plant is used to treat stomach cancer and urinary tract infections. Likewise, compounds and extracts isolated from plants have shown cytotoxic and anti-inflammatory effects. Theobjective of this study was to evaluate the photochemoprotective effect of topical treatment with the methanolic extract of L. racemosa (MELR) as a photochemoprotective agent against the harmful effects of UV irradiation (UVR) on a bacterial model and hairless mice. The MELR components were separated and analyzed via HPLC-UV-ESI-MS. Antioxidant activity was evaluated by the ability of MERL to scavenge DPPH and ABTS free radicals and by its FRAP capacity. The toxicity of MELR was evaluated in keratinocyte cultures. The photoprotective capacity of MELR was assessed through challenge experiments using models with bacteria and hairless CD1 et/et mice; cytokines related to the damage caused by UVR were also measured. In the methanolic extract of L. racemosa, five metabolites were detected and identified: two isomers of quercetin 6-C glycoside, orientin, quercetin 3-(6″-acetylglycoside) and quercetin 3-(6″-galloylglycoside) 7-(2,3-dihydroxytetrahydro-2H-pyran-4-yl acetate). MELR exhibited DPPH and ABTS radical scavenging properties, in addition to Fe ion reducing activity. MELR showed a photoprotective effect against UVB radiation-induced death in Escherichia coli bacteria. At the histological level, topical treatment of CD-1 et/et mice with MERL reduced the damage caused by UVR. Quantification of interleukins in the blood of mice revealed that the expression of IL-12 was greater in the control group treated with ultraviolet radiation than in the group protected with MELR. The methanolic extract of L. racemosa has photochemoprotective properties.

Fludarabine Enhances Radiosensitivity by Promoting Ferroptosis in B-Cell Lymphoma.

The objective of this study is to investigate the impact of fludarabine, a signal transducer and activator of transcription-1 (STAT1) inhibitor, on the radiosensitivity of B-cell lymphoma (BCL) and to explore the underlying mechanisms. Radiotherapy is one of the primary treatments for BCL, and STAT1 plays a critical role in the transcription of cell proliferation-related genes, which are associated with radiotherapy and ferroptosis. This study aims to determine whether fludarabine can enhance the radiosensitivity of BCL and to elucidate the molecular pathways involved. Various in vitro methodologies, including CCK-8 assays, clonogenic formation assays, immunohistochemistry, immunofluorescence, flow cytometry, qRT-PCR, and Western blot analyses, were employed in B-cell lymphoma cell models to thoroughly investigate the effects of fludarabine on radiosensitivity. Subsequently, the obtained results were further validated through invivo animal models and by examining human diffuse large B-cell lymphoma (DLBCL) cancer samples. Our findings demonstrate that the combination of fludarabine and irradiation synergistically inhibits cell viability and colony formation, while inducing apoptosis and ferroptosis in B-cell lymphoma cell lines Raji and Su-DHL-10. Moreover, fludarabine was found to enhance the ferroptosis induced by radiation, thereby synergistically impeding the growth of BCL. In vivo experiments confirmed these findings, revealing that the intraperitoneal injection of fludarabine significantly enhanced the inhibitory effects of radiation on Raji cell xenograft models, leading to an increased percentage of ferroptosis compared to models without fludarabine. Additionally, the administration of liproxstatin-1, a ferroptosis inhibitor, attenuated the inhibition of xenograft growth caused by the combination of fludarabine and irradiation. Furthermore, our analysis of clinical data revealed that increased co-expression of STAT1 and GPX4 is associated with poor overall survival in patients with diffuse large B-cell lymphoma. These results highlight the potential of fludarabine to enhance radiosensitivity and ferroptosis induction as a promising therapeutic strategy for BCL. Our results demonstrated that fludarabine promoted radiation-induced BCL death through the ferroptosis pathway. We have identified a previously unrecognized mechanism in the fludarabine and radiation combination, indicating that it is necessary to conduct prospective clinical trials to verify this new treatment regimen in BCL.

Mechanical and structural properties of rat and human lymphocytes after the exposure of the whole blood to X-rays in vitro

Objective. By the means of atomic force microscopy to determine the changes in the parameters of the structural and mechanical properties of peripheral blood lymphocytes induced by the irradiation of whole blood by X-rays and identifying the possibility of assessing a state and radiation-induced lymphocyte death programs by analyzing a set of such parameters.Materials and methods. Whole blood of rats and humans was irradiated with X-rays (1–100 Gy) in vitro. Lymphocytes were isolated from the blood after a day of storage, placed on glass slides, fixed with glutaraldehyde and dried. The study of structural and mechanical properties was carried out with the help of atomic force microscope Bruker Bioscope Resolve in Peak Force QNM mode in air. For the sets of AFM parameters, which included elastic modulus, adhesion force, cell surface roughness and cell sizes, a k-mean clustering of data was carried out for the studied experimental groups.Results. The X-ray irradiation of the blood caused changes in the structural and mechanical properties of lymphocytes measured by AFM at the nanoscale. Clustering analysis of the sets of AFM parameters revealed clusters with similar structure in each experimental group (humans, 6and 16-month rats). The studied four clusters were associated with cell states and cell death programs: non-activated cells, activated cells with increased stiffness, apoptotic cells with reduced stiffness, and cells dying via programs other than apoptotic ones with increased stiffness. Each cluster (cell type) with a specific set of AFM parameters was represented differently in the blood lymphocyte population, depending on the dose of X-rays.Conclusion. The set of ACM parameters of lymphocytes including elastic modulus, adhesion force, roughness, and cell sizes, can be helpful for automatically determining the state and death program of lymphocytes after the local irradiation of humans with the involvement of peripheral blood (for example, after radio-therapeutic causes).

Estimating the risk of cancer incidence and radiation-induced cancer death of children patients undergoing digital radiology X-ray examinations

BackgroundIt is generally accepted that children are more sensitive to radiation than adults and have a higher relative risk of cancer. The longer life expectancy after exposure increases the risk of developing radiation-associated malignancies. PurposeThis study aims to estimate the risk of cancer incidence and radiation-induced cancer death of children patients undergoing digital radiology X-ray examinations. Material and methodsIn this study, data were collected retrospectively from 15 radiography rooms in the major radiology centers in Mazandaran province (Iran). The information of 12 common digital radiography examinations including pelvis (in the anteroposterior projection (AP)), skull (in the two lateral projection (LAT) and posteroanterior projection (PA)), abdomen (AP), cervical vertebra (AP and LAT), chest (PA and LAT), lumbar vertebra (AP and LAT), thoracic vertebra (AP and LAT) examinations which was recorded from 10 to 15 years old patients. The Entrance Surface Air Kerma (ESAK), Entrance Skin Dose (ESD), and Organ Effective Dose (ED) were measured. Finally, the risk of cancer incidence and Risk of Exposure-Induced cancer Death (REID) values were estimated for these patients. ResultsIn total, 1800 (983 females and 817 males) patients (10–15 years old) were included in this study. Across all procedures, the lowest ED belonged to the skull (PA) examination (10.40 μSv), and the highest ED belonged to the AP abdominal imaging technique (378.46 μSv). The highest ESD was related to the lumbar spine (LAT) projection (3.62 ± 1.38 mGy) and the least to the cervical vertebra (AP) view (0.97 ± 0.21). It was also shown that the differences in cancer incidence and radiation-induced cancer death values in male and female patients were not statistically significant. ConclusionThe result showed that ESDs are influenced by various factors that affect patients' dose distributions, so through the optimization of imaging parameters, image quality can be increased and the patient dose reduced. These actions will necessarily decrease the risk of cancer incidence and radiation-induced mortality risk. Further studies are recommended to assess the workplace environment and practical training in radiology institutions, along with the quality control tests of radiology devices.

Comparison of typical radiation doses and risks using an anthropomorphic 'bone fracture' phantom for commonly performed X-ray projections in a 5-year-old.

Diagnostic reference levels (DRLs) are typical dose levels for medical imaging examinations for groups of standard-sized patients or standard phantoms for broadly defined types of equipment used as a tool to aid optimisation of protection for medical exposures. Currently, there are no paediatric DRLs for conventional radiography (i.e. general X-rays) published in Australia. The aim of this study was to establish typical radiation doses and risks that are representative of those delivered for commonly performed X-ray projections for a 5-year-old/20 kg child using a 5-year-old anthropomorphic 'bone fracture' phantom in three dedicated paediatric radiology departments in Victoria. A total of 20 projection images were acquired for a standard 5-year-old/20 kg phantom using digital radiography X-ray equipment. The air kerma-area product (KAP) measured at each centre by a KAP metre, which was calibrated to a national primary standard, was considered to represent the median value for that centre for each X-ray projection. Organ doses and effective dose were estimated using PCXMC software, and risks of radiation-induced cancer and radiation-induced death were calculated based on the BEIR VII report. The typical doses for the individual X-ray projections ranged from 3 mGy•cm2 to 86 mGy•cm2 , whilst the effective doses ranged from 0.00004 to 0.07 mSv. The radiation risks were 'minimal' to 'negligible'. The estimation of typical radiation doses and associated risks for a 5-year-old/20 kg phantom study provides reference values for guidance and is a first step in assisting optimisation at other institutions until national DRLs, based on patient data from the clinical setting, are published.

Sublethal whole-body irradiation induces permanent loss and dysfunction in pre-existing pathogen-specific memory CD8 T cell populations

Abstract The increasing use of nuclear energy sources inevitably increases the risk of accidental or deliberate radiation-exposure. However, the extent to which radiation-exposure impacts memory CD8 T cells, potent mediators of immunity to recurring intracellular infections and malignancies, remains understudied. Using P14 LCMV immune chimeric mice (P14 chimeras), we observed that sublethal (5Gy) whole body irradiation (WBI) induced a rapid decline in the number of naive (T N) and P14 circulatory memory CD8 T cells (T CIRCM) with the former being more susceptible to radiation-induced death. While T Ncell numbers rapidly recovered, the number of P14 T CIRCMcells remained low at least nine months after radiation-exposure. Additionally, the remaining P14 T CIRCMin irradiated hosts exhibited an inefficient transition to a central memory (CD62L hi) phenotype compared to non-irradiated P14 chimeras. WBI also resulted in long-lasting T-cell intrinsic deficits including diminished cytokine and chemokine production in response to antigen-stimulation along with impaired secondary expansion upon cognate Ag re-encounter. Irradiated P14 chimeras displayed significantly higher bacterial burden after challenge with L. monocytogenes expressing GP33 compared with the non-irradiated controls, likely due to radiation-induced numerical and functional impairments. Taken together, our findings suggest that sublethal radiation-exposure caused long-term numerical decline, impaired differentiation, and functional dysregulation in pre-existing T CIRCM, which rendered previously-protected hosts susceptible to re-infections. Supported by NIH Grants GM134880, AI114543, The Holden Comprehensive Cancer Center at The University of Iowa and its National Cancer Institute Award P30CA086862

First Documentation of Cell-to-Cell Peroxisome Transfer in Hematopoietic Stem and Progenitor Cells: A Method to "Relieve Stress"?

Cell to cell communication is key to survival. Recently it has been demonstrated that intercellular transfer of mitochondria occurs and can aid in marrow recovery after irradiation. Peroxisomes are a single membrane bound organelle responsible for various functions including lipid metabolism and protecting the cell from oxidative damage by reactive oxygen species (ROS). We have created the first mouse model in which peroxisomes can be tracked in living tissues using GFP tagged with a peroxisome targeting signal sequence (PTS), under the control of the Rosa promoter. Such GFP-PTS animals showed widespread peroxisomal GFP expression in all organs including hematopoietic stem and progenitor cells (HSPC) such as LSK-SLAM. Marrow stroma cell lines were established from GFP-PTS animals. In vitro peroxisome transfer from stroma to HSPC showed a transfer rate of up to 0.5 %, which could be achieved only when cell-to-cell contact took place; the use of transwells inhibited transfer. When HSPCs were simulated to proliferate, peroxisome transfer dropped by 50.1% (p<0.0001). The ability of HSPC to take up peroxisomes in vivo was tested in a model of hematopoietic cell transplant (HCT). Using GFP-PTS mice as recipients with wild-type (WT) marrow donors, we found that after busulfan or radiation (9 Gy) conditioning, peroxisome transfer could occur into WT adoptively HSPC within 48 hours after HCT at a rate of 1%. At 3 months post HCT, bone marrow mononuclear cells (BMMC) and Lin-SCA1+CKIT+ (LSK) were 100% donor and maintained GFP+peroxisomes at a frequency of 0.9% which were transferred from surrounding niche/stroma cells. To test HSPC to HSPC peroxisome transfer, sublethal conditioning (4.5 Gy) of WT was used to generate mixed chimerism models with marrow from GFP-PTS mice used as donor. Total peripheral or marrow engraftment was 45-55% donor as expected at 3 months post-HCT. WT BMMC could take up peroxisomes at a 0.9% frequency, while LSK had a significantly higher peroxisome uptake of 3.9% (p=0.02) indicating greater efficiency. Results were similar if GFP-PTS+ animals were recipients in a sublethal transplant setting. Remarkably, we could also demonstrate that peroxisome transfer can occur between GFP-PTS donor hematopoietic cells and WT cells in the liver, spleen, thymus, and brain after HCT. The genetic deletion of peroxisomes (via pex1 knockout) in animals resulted in ROS levels 10.3-fold over that of wild-type in PBMC, BMMC, and LSK (p<0.0001) as assessed by CellROX assay. Such animals had a severe defect in growth, had normal hematopoiesis, and increased radiation sensitivity indicating the importance of peroxisomes in reducing oxidative stress. To test the hypothesis that peroxisome transfer is utilized in situations of increased oxidative stress, pex1 KO stroma lines were exposed to increasing doses of radiation followed by incubation with GFP-PTS+ BMMC. Radiation treatment enhanced peroxisome transfer 5.1-fold over no-irradiated control (p<0.01), and cells receiving donor peroxisomes had greater viability (84% vs 68% viable, p<0.01) and reduced levels oxidative stress 24.8% compared to cell not receiving peroxisomes (p=0.03). The entire system was reproduced in a zebrafish model expressing GFP-PTS. Sublethally irradiated WT zebrafish engrafted donor GFP-PTS+ marrow at 50% and showed a significantly high rate of peroxisome uptake of into WT HSPS of 30% at 3 months post-HCT, suggesting some species may perform peroxisome transfer at much greater rates than others. In conclusion, we have demonstrated, for the first time, that peroxisome transfer can occur between a wide variety of cell types in vitro and in vivo, and HSPC-to-HSPC peroxisome transfer seems to be the most robust. The ability of peroxisome transfer to rescue cells from radiation-induced ROS and death was demonstrated in vitro while in vivo experiments are proceeding. There may be other far-reaching effects in terms of altering cellular metabolism occurring as a result of peroxisome transfer remaining to be discovered.

Miat and interacting protein Metadherin maintain a stem-like niche to promote medulloblastoma tumorigenesis and treatment resistance

Long noncoding RNAs (lncRNAs) play essential roles in the development and progression of many cancers. However, the contributions of lncRNAs to medulloblastoma (MB) remain poorly understood. Here, we identify Miat as an lncRNA enriched in the sonic hedgehog group of MB that is required for maintenance of a treatment-resistant stem-like phenotype in the disease. Loss of Miat results in the differentiation of tumor-initiating, stem-like MB cells and enforces the differentiation of tumorigenic stem-like MB cells into a nontumorigenic state. Miat expression in stem-like MB cells also facilitates treatment resistance by down-regulating p53 signaling and impairing radiation-induced cell death, which can be reversed by therapeutic inhibition of Miat using antisense oligonucleotides. Mechanistically, the RNA binding protein Metadherin (Mtdh), previously linked to resistance to cytotoxic therapy in cancer, binds to Miat in stem-like MB cells. Like the loss of Miat, the loss of Mtdh reduces tumorigenicity and increases sensitivity to radiation-induced death in stem-like MB cells. Moreover, Miat and Mtdh function to regulate the biogenesis of several microRNAs and facilitate tumorigenesis and treatment resistance. Taken together, these data reveal an essential role for the lncRNA Miat in sustaining a treatment-resistant pool of tumorigenic stem-like MB cells.

Typical median effective radiation doses using an anthropomorphic bone fracture phantom for initial radiographic skeletal surveys in the investigation of suspected physical abuse

BackgroundA series of 31 radiographs is recommended by the Royal College of Radiologists (RCR) when investigating suspected physical abuse (SPA).ObjectiveTo determine the radiation dose delivered for skeletal surveys performed for SPA in Victorian radiology departments based on their local protocols.Materials and methodsA 5-year-old paediatric bone fracture phantom was radiographed at five radiology sites using both the RCR recommended protocol and, where applicable, the local departmental SPA protocol. The radiation doses were measured and recorded. These were scaled down to estimate the effective radiation doses for a 2-year-old child at each site and the associated radiation risks estimated.ResultsThe median effective dose for all radiographic projections in the RCR skeletal survey radiographic series was 0.09 mSv. The estimated risk of radiation-induced cancer and radiation-induced death from cancer for 2-year-old children is classified as “very low,” with girls having a higher risk than boys.ConclusionThe median effective radiation dose for the RCR skeletal survey for imaging in SPA was 0.09 mSv resulting in a “very low” additional risk of radiation-induced cancer. The authors will now aim to ascertain whether whole-body CT skeletal survey can replace the radiographic series for imaging in SPA while maintaining a comparable radiation dose.

Significant Reduction of Total-Body Irradiation-Induced Death in Mice Treated with PrC-210 24 Hours Postirradiation.

The search for radiation countermeasures that can serve as: i. a pre-exposure agent to protect against subsequent irradiation, and/or ii. a post-exposure agent to mitigate the development of Acute Radiation Syndrome after radiation exposure, remains a prominent goal of the U.S. Government. This study was undertaken to determine whether PrC-210, when administered once, 24 h postirradiation, would provide a survival benefit and would mitigate Acute Radiation Syndrome in mice that had received an otherwise 95-100% lethal radiation dose. Our results show that a single intraperitoneal dose of PrC-210 (0.3-0.4 MTD, 151-201 ug/gm body weight) administered 24 h postirradiation, conferred: i. a 45% survival advantage (P = 0.002) in outbred ICR mice and a 25% survival advantage (P = 0.037) in inbred C57Bl/6 mice, ii. a significant increase in body weight in surviving mice (P = 0.012), iii. a discernible protection of intestinal structure by MRI imaging of live mice, iv. visibly denser jejunal villi and surface epithelium and v. visible bone marrow population in PrC-210-treated mice versus saline controls. The ability of PrC-210 to suppress 100% of radiation-induced death when administered minutes before irradiation, or roughly half of this effect (45%) when administered 24 h postirradiation is noteworthy. Determining the multiple paths by which PrC-210 protection is conferred is a process; the results in this report showing protection of two of the major systems central to Acute Radiation Syndrome damage, is a good first step. This was the first study of PrC-210 administered postirradiation; it conferred substantial survival benefit and suppression of Acute Radiation Syndrome. This outcome supports the continued development of PrC-210 to protect humans exposed to ionizing radiation.

Amomum subulatum mitigates total body irradiation-induced oxidative stress and its associated inflammatory response by enhancing the antioxidant status and regulating the pro-inflammatory cytokines

Free radical-induced oxidative damage and associated inflammatory responses play a crucial role in cancer radiotherapy (RT) mediated normal tissue toxicities. Supplementation of antioxidants or inflammation modulators may alleviate RT toxicity, thereby improving clinical outcomes. Amomum subulatum is a dietary spice rich in biologically active phytochemicals. The present study investigates radiation dose-modifying factor (DMF) and radioprotective efficacy of methanolic extract of Amomum subulatum dry fruits (MEAS) in mice exposed to different doses of total body irradiation (TBI). Administration of MEAS resulted in a DMF of 1.25 Gy, ascertaining its radioprotective efficacy. MEAS reversed X-ray-induced redox imbalance by enhancing antioxidant defense mechanisms. MEAS prevented TBI-induced hematopoietic damages by significantly (P<.01) enhancing bone marrow cellularity, total white blood cell count, and hemoglobin level. MEAS prevented p53-mediated apoptotic death of intestinal cells and increased the expression of cytoprotective genes Nrf2 (nuclear factor-erythroid factor 2-related factor 2) and HO-1 (heme oxygenase-1). Expression of apoptosis regulating genes revealed that MEAS reduced radiation-induced apoptotic death of intestinal cells. Treatment with MEAS also reduced inflammatory responses via reversing TBI-induced elevation in serum pro-inflammatory cytokine (TNF-α, IL-1β, IL-6) levels. Tissue histopathology further confirmed the protective effect of MEAS against TBI-induced inflammatory responses, suggesting the potential of MEAS in modulating inflammation. These effects might perhaps be attributed to the synergistic effect of biologically active polyphenols with antioxidant, anti-inflammatory, and Nrf2 activating potential in MEAS. Our findings demonstrated the radioprotective efficacy of MEAS, suggesting the possible nutraceutical application of Amomum subulatum in modulating oxidative stress and inflammation.

Radiosensitization of PC3 Prostate Cancer Cells by 5-Thiocyanato-2'-deoxyuridine.

Simple SummaryRadiation therapy is one of the main treatments for cancer. However, the success of treatment by radiation therapy is largely dependent on tumor radiosensitivity. To improve therapeutic outcomes, radiation therapy should be combined with the use of a radiosensitizer which enables irradiation at lower doses with higher efficacies. 5-Thiocyanato-2′-deoxyuridine has been reported as a potential radiosensitizer of DNA damage based on advanced radiation chemical studies. In this paper, for the first time, we demonstrate the radiosensitizing properties of this modified nucleoside at the cellular level. The tested analogue increases the sensitivity of prostate cancer cells to ionizing radiation which is, at least partially, related to an increase in the number of DNA double-strand breaks and cell cycle regulation.Purpose: The radiosensitizing properties of uracil analogs modified in the C5 position are very interesting in the context of their effectiveness and safety in radiation therapy. Recently, radiation chemical studies have confirmed that 5-thiocyanato-2′-deoxyuridine (SCNdU) undergoes dissociation induced by an excess electron attachment and established this nucleoside as a potential radiosensitizer. In this paper, we verify the sensitizing properties of SCNdU at the cellular level and prove that it can effectively enhance ionizing radiation-induced cellular death. Methods and Materials: Prostate cancer cells were treated with SCNdU and irradiated with X rays. The cytotoxicity of SCNdU was determined by MTT test. Cell proliferation was assessed using a clonogenic assay. Cell cycle analyses, DNA damage, and cell death analyses were performed by flow cytometry. Results: SCNdU treatment significantly suppressed the proliferation and increased the radiosensitivity of prostate cancer cells. The radiosensitizing effect expressed by the dose enhancement factor is equal to 1.69. Simultaneous exposure of cells to SCNdU and radiation causes an increase in the fraction of the most radiosensitive G2/M phase, enhancement of the histone H2A.X phosphorylation level, and apoptosis induction. Finally, SCNdU turned out to be marginally cytotoxic in the absence of ionizing radiation. Conclusions: Our findings indicate that SCNdU treatment enhances the radiosensitivity of prostate cancer cells in a manner associated with the cell cycle regulation, double strand formation, and a slight induction of apoptosis.

Evaluation of Sinapic Acid to Ameliorate Ionizing Radiation Induced Peripheral Blood Mononuclear Cell Death

Introduction: The UV radiation is known as a potential environmental carcinogen which causes damages of macromolecules like DNA, RNA, lipid, and protein inside the cell and eventually causes cell death. Persons who chronically exposed to UV radiation due to occupational or environmental exposure have a potential risk to develop cancer of the skin and internal organs. Polyphenols have a promising role in scavenging reactive oxygen species developed in our body due to a variety of exposure including radiation. In the present study, we are therefore evaluating the role of sinapic acid (SA), a polyphenol, in scavenging UV radiation-induced generation of reactive oxygen species and eventual cell death. We have studied the biological activity of SA as a potential antioxidant on human peripheral blood mononuclear cells taken from human volunteers. Methods : Graded concentration of SA in different solvent mediums was applied to UV exposed peripheral blood mononuclear cells for evaluating the best effective delivery system and concentration against UV radiation. Result: After series of experiments, we have observed that even at 10 µM concentration, SA is effective against UV induced cellular death. Conclusion: Finally, from this work we are inviting lots of works in this field to establish this molecule as a medicine to reduce radiation-induced cellular death.

SERPINB3 (SCCA1) inhibits cathepsin L and lysoptosis, protecting cervical cancer cells from chemoradiation

The endogenous lysosomal cysteine protease inhibitor SERPINB3 (squamous cell carcinoma antigen 1, SCCA1) is elevated in patients with cervical cancer and other malignancies. High serum SERPINB3 is prognostic for recurrence and death following chemoradiation therapy. Cervical cancer cells genetically lacking SERPINB3 are more sensitive to ionizing radiation (IR), suggesting this protease inhibitor plays a role in therapeutic response. Here we demonstrate that SERPINB3-deficient cells have enhanced sensitivity to IR-induced cell death. Knock out of SERPINB3 sensitizes cells to a greater extent than cisplatin, the current standard of care. IR in SERPINB3 deficient cervical carcinoma cells induces predominantly necrotic cell death, with biochemical and cellular features of lysoptosis. Rescue with wild-type SERPINB3 or a reactive site loop mutant indicates that protease inhibitory activity is required to protect cervical tumor cells from radiation-induced death. Transcriptomics analysis of primary cervix tumor samples and genetic knock out demonstrates a role for the lysosomal protease cathepsin L in radiation-induced cell death in SERPINB3 knock-out cells. These data support targeting of SERPINB3 and lysoptosis to treat radioresistant cervical cancers.

Evaluation of Sinapic Acid to Ameliorate Ionizing Radiation Induced Peripheral Blood Mononuclear Cell Death

Introduction: The UV radiation is known as a potential environmental carcinogen which causes damages of macromolecules like DNA, RNA, lipid, and protein inside the cell and eventually causes cell death. Persons who chronically exposed to UV radiation due to occupational or environmental exposure have a potential risk to develop cancer of the skin and internal organs. Polyphenols have a promising role in scavenging reactive oxygen species developed in our body due to a variety of exposure including radiation. In the present study, we are therefore evaluating the role of sinapic acid (SA), a polyphenol, in scavenging UV radiation-induced generation of reactive oxygen species and eventual cell death. We have studied the biological activity of SA as a potential antioxidant on human peripheral blood mononuclear cells taken from human volunteers. Methods : Graded concentration of SA in different solvent mediums was applied to UV exposed peripheral blood mononuclear cells for evaluating the best effective delivery system and concentration against UV radiation. Result: After series of experiments, we have observed that even at 10 µM concentration, SA is effective against UV induced cellular death. Conclusion: Finally, from this work we are inviting lots of works in this field to establish this molecule as a medicine to reduce radiation-induced cellular death.

Radiosensitization of calreticulin-overexpressing human glioma cell line by the polyphenolic acetate 7, 8-diacetoxy-4-methylcoumarin.

Calreticulin (CRT), an endoplasmic reticulum-resident protein generally overexpressed in cancer cells, is associated with radiation resistance. CRT shows higher transacetylase activity, as shown by us earlier, in the presence of the polyphenolic acetates (like 7, 8-diacetoxy-4-methylcoumarin, DAMC) and modifies the activity of a number of proteins, thereby influencing cell signaling. To investigate the relationship between CRT expression and radiation response in a human glioma cell line and to evaluate the radiomodifying effects of DAMC. Studies were carried out in an established human glioma cell line (BMG-1) and its isogenic clone overexpressing CRT (CROE, CRT-overexpressing cells) by analyzing clonogenic survival, cell proliferation, micronuclei analysis, and protein levels by Western blotting as parameters of responses. CRT overexpression conferred resistance against radiation-induced cell death in CROE cells (D37 =7.35 Gy, D10 =12.6Gy and D0 =7.25 Gy) as compared to BMG-1 cells (D37 =5.70 Gy, D10 =9.2Gy and D0 =5.6Gy). A lower level of radiation-induced micronuclei formation observed in CROE cells suggested that reduced induction and/or enhanced DNA repair partly contributed to the enhanced radioresistance. Consistent with this suggestion, we noted that CRT-mediated radioresistance was coupled with enhanced grp78 level and reduced P53 activation-mediated prodeath signaling, while no changes were noted in acetylation of histone H4. DAMC-enhanced radiation-induced delayed (secondary) apoptosis, which was higher in CROE cells. CRT overexpression confers resistance against radiation-induced death of human glioma cells, which can be overcome by the polyphenolic acetate DAMC.