Revisiting the Historic Strontium-90 Ingestion Beagle Study Conducted at the University of California Davis: Opportunity in Archival Materials.

Strontium-90 is a radionuclide found in high concentrations in nuclear reactor waste and nuclear fallout from reactor accidents and atomic bomb explosions. In the 1950s, little was known regarding the health consequences of strontium-90 internalization. To assess the health effects of strontium-90 ingestion in infancy through adolescence, the Atomic Energy Commission and Department of Energy funded large-scale beagle studies at the University of California Davis. Conducted from 1956 to 1989, the strontium-90 ingestion study followed roughly 460 beagles throughout their lifespans after they were exposed to strontium-90 in utero (through feeding of the mother) and fed strontium-90 feed at varying doses from weaning to age 540 days. The extensive medical data and formalin-fixed paraffin-embedded tissues were transferred from UC Davis to the National Radiobiology Archive in 1992 and subsequently to the Northwestern University Radiobiology Archive in 2010. Here, we summarize the design of the strontium-90 ingestion study and give an overview of its most frequent recorded findings. As shown before, radiation-associated neoplasias (osteosarcoma, myeloproliferative syndrome and select squamous cell carcinomas) were almost exclusively observed in the highest dose groups, while the incidence of neoplasias most frequent in controls decreased as dose increased. The occurrence of congestive heart failure in each dose group, not previously assessed by UC Davis researchers, showed a non-significant increase between the controls and lower dose groups that may have been significant had sample sizes been larger. Detailed secondary analyses of these data and samples may uncover health endpoints that were not evaluated by the team that conducted the study.

Gene Expression and Early Radiation Response of Two Distinct Neuroblastoma Cell Lines.

INTRODUCTION: Neuroblastoma is one of the most common childhood cancers with one of the lowest survival rates, accounting for 15% of childhood cancer mortality. Approximately half of children treated for high-risk neuroblastoma will relapse following remission, while another 15% of patients do not respond to initial treatment. External beam radiation is infrequently used for treatment of pediatric cancer such as neuroblastoma, typically reserved for palliative care in patients with aggressive metastatic disease who fail to respond to alternative treatments. Understanding effects of radiation on neuroblastoma cells could improve efficacy of this final means of therapy to decrease tumor burden and stabilize the disease. METHODS: In this study, we found that two microRNAs with opposite functions were expressed in two neuroblastoma cell lines with marked differences in radiosensitivity. Clonogenic assays were used to evaluate the radiation responses for these 2 cell lines, designated SK-N-AS and SK-N-DZ; cells were then irradiated at doses that cause 90% cell killing based on clonogenic assay and their RNA isolated and subjected to microarray analysis. In addition, cells were transfected with pre-miRNA constructs that led to overexpression of microRNAs miR-34a and miR-1228 to determine possible microRNA regulation of radiation response. RESULTS: Statistically significant differences were detected for expression of several thousand genes when the 2 cell lines were compared with each other. In comparison, radiation exposure resulted in only minor gene expression differences of less than 2-fold at the 1 h postirradiation timepoint in both cell lines. Overexpression of miR-34a and miR-1228 in either cell line did not alter this outcome. DISCUSSION: While these two neuroblastoma cell lines are phenotypically diverse and gene expression differences between them are extensive, we observed that the regulation of gene expression in both cell lines is in a stable equilibrium at early timepoints after exposure to ionizing radiation.

Lessons learned in the practice of community-based participatory research with community partner collaboration in study design and implementation: the community scientist model.

Engagement of community participation is an innovative driver of modern research. However, to benefit the communities being studied, it is imperative to continuously evaluate ethical considerations, the relationship dynamic between researchers and community members, and the responsiveness of research teams to the needs and preferences of communities. Northwestern University's Center for Health Equity Transformation founded a community scientist program in 2018 that implemented a study using the Community-Based Participatory Research (CBPR) model. This project is an ongoing study of heavy metal exposure by geographic location in Chicago. Community scientists from various backgrounds, communities, and organizations formed an advisory panel, partnering with the cancer research team. This commentary describes lessons learned in structuring meaningful community involvement and benefit in CBPR, with a focus on three lessons learned that relate to ethics, relationships, and responsiveness. Our findings lay new groundwork for iteratively shaping best practices in CBPR.

PERIOD 2 regulates low-dose radioprotection via PER2/pGSK3ß/ß-catenin/Per2 loop.

During evolution, humans are acclimatized to the stresses of natural radiation and circadian rhythmicity. Radiosensitivity of mammalian cells varies in the circadian period and adaptive radioprotection can be induced by pre-exposure to low-level radiation (LDR). It is unclear, however, if clock proteins participate in signaling LDR radioprotection. Herein, we demonstrate that radiosensitivity is increased in mice with the deficient Period 2 gene (Per2def) due to impaired DNA repair and mitochondrial function in progenitor bone marrow hematopoietic stem cells and monocytes. Per2 induction and radioprotection are also identified in LDR-treated Per2wt mouse cells and in human skin (HK18) and breast (MCF-10A) epithelial cells. LDR-boosted PER2 interacts with pGSK3ß(S9) which activates ß-catenin and the LEF/TCF mediated gene transcription including Per2 and genes involved in DNA repair and mitochondrial functions. This study demonstrates that PER2 plays an active role in LDR adaptive radioprotection via PER2/pGSK3ß/ß-catenin/Per2 loop, a potential target for protecting normal cells from radiation injury.

Radiation dose rate effects: what is new and what is needed?

Despite decades of research to understand the biological effects of ionising radiation, there is still much uncertainty over the role of dose rate. Motivated by a virtual workshop on the "Effects of spatial and temporal variation in dose delivery" organised in November 2020 by the Multidisciplinary Low Dose Initiative (MELODI), here, we review studies to date exploring dose rate effects, highlighting significant findings, recent advances and to provide perspective and recommendations for requirements and direction of future work. A comprehensive range of studies is considered, including molecular, cellular, animal, and human studies, with a focus on low linear-energy-transfer radiation exposure. Limits and advantages of each type of study are discussed, and a focus is made on future research needs.

Findings from international archived data: Fractionation reduces mortality risk of ionizing radiation for total doses below 4 Gray in rodents.

Ionizing radiation is omnipresent and unavoidable on Earth; nevertheless, the range of doses and modes of radiation delivery that represent health risks remain controversial. Radiation protection policy for civilians in US is set at 1 mSv per year. Average persons from contemporary populations are exposed to several hundred milliSieverts (mSv) over their lifetimes from both natural and human made sources such as radon, cosmic rays, CT-scans (20-50 mSv partial body exposure per scan), etc. Health risks associated with these and larger exposures are focus of many epidemiological studies, but uncertainties of these estimates coupled with individual and environmental variation make it is prudent to attempt to use animal models and tightly controlled experimental conditions to supplement our evaluation of radiation risk question. Data on 11,528 of rodents of both genders exposed to x-ray or gamma-ray radiation in facilities in US and Europe were used for this analysis; animal mortality data argue that fractionated radiation exposures have about 2 fold less risk per Gray than acute radiation exposures in the range of doses between 0.25 and 4 Gy.

Radiation biology workforce in the United States.

In recent decades, the principal goals of participants in the field of radiation biologists have included defining dose thresholds for cancer and non-cancer endpoints to be used by regulators, clinicians and industry, as well as informing on best practice radiation utilization and protection applications. Importantly, much of this work has required an intimate relationship between "bench" radiation biology scientists and their target audiences (such as physicists, medical practitioners and epidemiologists) in order to ensure that the requisite gaps in knowledge are adequately addressed. However, despite the growing risk for public exposure to higher-than-background levels of radiation, e.g. from long-distance travel, the increasing use of ionizing radiation during medical procedures, the threat from geopolitical instability, and so forth, there has been a dramatic decline in the number of qualified radiation biologists in the U.S. Contributing factors are thought to include the loss of applicable training programs, loss of jobs, and declining opportunities for advancement. This report was undertaken in order to begin addressing this situation since inaction may threaten the viability of radiation biology as a scientific discipline.

Development of Fe3O4 core-TiO2 shell nanocomposites and nanoconjugates as a foundation for neuroblastoma radiosensitization.

BACKGROUND: Neuroblastoma is the most common extracranial solid malignancy in childhood which, despite the current progress in radiotherapy and chemotherapy protocols, still has a high mortality rate in high risk tumors. Nanomedicine offers exciting and unexploited opportunities to overcome the shortcomings of conventional medicine. The photocatalytic properties of Fe3O4 core-TiO2 shell nanocomposites and their potential for cell specific targeting suggest that nanoconstructs produced using Fe3O4 core-TiO2 shell nanocomposites could be used to enhance radiation effects in neuroblastoma. In this study, we evaluated bare, metaiodobenzylguanidine (MIBG) and 3,4-Dihydroxyphenylacetic acid (DOPAC) coated Fe3O4@TiO2 as potential radiosensitizers for neuroblastoma in vitro. RESULTS: The uptake of bare and MIBG coated nanocomposites modestly sensitized neuroblastoma cells to ionizing radiation. Conversely, cells exposed to DOPAC coated nanocomposites exhibited a five-fold enhanced sensitivity to radiation, increased numbers of radiation induced DNA double-strand breaks, and apoptotic cell death. The addition of a peptide mimic of the epidermal growth factor (EGF) to nanoconjugates coated with MIBG altered their intracellular distribution. Cryo X-ray fluorescence microscopy tomography of frozen hydrated cells treated with these nanoconjugates revealed cytoplasmic as well as nuclear distribution of the nanoconstructs. CONCLUSIONS: The intracellular distribution pattern of different nanoconjugates used in this study was different for different nanoconjugate surface molecules. Cells exposed to DOPAC covered nanoconjugates showed the smallest nanoconjugate uptake, with the most prominent pattern of large intracellular aggregates. Interestingly, cells treated with this nanoconjugate also showed the most pronounced radiosensitization effect in combination with the external beam x-ray irradiation. Further studies are necessary to evaluate mechanistic basis for this increased radiosensitization effect. Preliminary studies with the nanoparticles carrying an EGF mimicking peptide showed that this approach to targeting could perhaps be combined with a different approach to radiosensitization - use of nanoconjugates in combination with the radioactive iodine. Much additional work will be necessary in order to evaluate possible benefits of targeted nanoconjugates carrying radionuclides. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12645-021-00081-z.

Use of X-Ray Fluorescence Microscopy for Studies on Research Models of Hepatocellular Carcinoma.

Introduction: TheraSphere® microspheres containing yttrium 90Y are among many radioembolization agents used clinically to reduce liver tumor burden, and their effects on cancer volume reduction are well-established. At the same time, concerns about off target tissue injury often limit their use. Deeper investigation into tissue distribution and long-term impact of these microspheres could inform us about additional ways to use them in practice. Methods: Healthy rat liver and rabbit liver tumor samples from animals treated with TheraSpheres were sectioned and their elemental maps were generated by X-ray fluorescence microscopy (XFM) at the Advanced Photon Source (APS) synchrotron at Argonne National Laboratory (ANL). Results: Elemental imaging allowed us to identify the presence and distribution of TheraSpheres in animal tissues without the need for additional sample manipulation or staining. Ionizing radiation produced by 90Y radioactive contaminants present in these microspheres makes processing TheraSphere treated samples complex. Accumulation of microspheres in macrophages was observed. Conclusions: This is the first study that used XFM to evaluate the location of microspheres and radionuclides in animal liver and tumor samples introduced through radioembolization. XFM has shown promise in expanding our understanding of radioembolization and could be used for investigation of human patient samples in the future.

Development of Multi-Scale X-ray Fluorescence Tomography for Examination of Nanocomposite-Treated Biological Samples.

Research in cancer nanotechnology is entering its third decade, and the need to study interactions between nanomaterials and cells remains urgent. Heterogeneity of nanoparticle uptake by different cells and subcellular compartments represent the greatest obstacles to a full understanding of the entire spectrum of nanomaterials' effects. In this work, we used flow cytometry to evaluate changes in cell cycle associated with non-targeted nanocomposite uptake by individual cells and cell populations. Analogous single cell and cell population changes in nanocomposite uptake were explored by X-ray fluorescence microscopy (XFM). Very few nanoparticles are visible by optical imaging without labeling, but labeling increases nanoparticle complexity and the risk of modified cellular uptake. XFM can be used to evaluate heterogeneity of nanocomposite uptake by directly imaging the metal atoms present in the metal-oxide nanocomposites under investigation. While XFM mapping has been performed iteratively in 2D with the same sample at different resolutions, this study is the first example of serial tomographic imaging at two different resolutions. A cluster of cells exposed to non-targeted nanocomposites was imaged with a micron-sized beam in 3D. Next, the sample was sectioned for immunohistochemistry as well as a high resolution "zoomed in" X-ray fluorescence (XRF) tomography with 80 nm beam spot size. Multiscale XRF tomography will revolutionize our ability to explore cell-to-cell differences in nanomaterial uptake.

Paramagnetic Mn8Fe4-co-Polystyrene Nanobeads as a Potential T1-T2 Multimodal Magnetic Resonance Imaging Contrast Agent with In Vivo Studies.

In developing a cluster-nanocarrier design, as a magnetic resonance imaging contrast agent, we have investigated the enhanced relaxivity of a manganese and iron-oxo cluster grafted within a porous polystyrene nanobead with increased relaxivity due to a higher surface area. The synthesis of the cluster-nanocarrier for the cluster Mn8Fe4O12(O2CC6H4CH═CH2)16(H2O)4, cross-linked with polystyrene (the nanocarrier), under miniemulsion conditions is described. By including a branched hydrophobe, iso-octane, the resulting nanobeads are porous and ∼70 nm in diameter. The increased surface area of the nanobeads compared to nonporous nanobeads leads to an enhancement in relaxivity; r1 increases from 3.8 to 5.2 ± 0.1 mM-1 s-1, and r2 increases from 11.9 to 50.1 ± 4.8 mM-1 s-1, at 9.4 teslas, strengthening the potential for T1 and T2 imaging. Several metrics were used to assess stability, and the porosity produced no reduction in metal stability. Synchrotron X-ray fluorescence microscopy was used to demonstrate that the nanobeads remain intact in vivo. In depth, physicochemical characteristics were determined, including extensive pharmacokinetics, in vivo imaging, and systemic biodistribution analysis.

Analyses of cancer incidence and other morbidities in neutron irradiated B6CF1 mice.

The Department of Energy conduced ten large-scale neutron irradiation experiments at Argonne National Laboratory between 1972 and 1989. Using a new approach to utilize experimental controls to determine whether a cross comparison between experiments was appropriate, we amalgamated data on neutron exposures to discover that fractionation significantly improved overall survival. A more detailed investigation showed that fractionation only had a significant impact on the death hazard for animals that died from solid tumors, but did not significantly impact any other causes of death. Additionally, we compared the effects of sex, age first irradiated, and radiation fractionation on neutron irradiated mice versus cobalt 60 gamma irradiated mice and found that solid tumors were the most common cause of death in neutron irradiated mice, while lymphomas were the dominant cause of death in gamma irradiated mice. Most animals in this study were irradiated before 150 days of age but a subset of mice was first exposed to gamma or neutron irradiation over 500 days of age. Advanced age played a significant role in decreasing the death hazard for neutron irradiated mice, but not for gamma irradiated mice. Mice that were 500 days old before their first exposures to neutrons began dying later than both sham irradiated or gamma irradiated mice.

A first-in-human phase 0 clinical study of RNA interference-based spherical nucleic acids in patients with recurrent glioblastoma.

Glioblastoma (GBM) is one of the most difficult cancers to effectively treat, in part because of the lack of precision therapies and limited therapeutic access to intracranial tumor sites due to the presence of the blood-brain and blood-tumor barriers. We have developed a precision medicine approach for GBM treatment that involves the use of brain-penetrant RNA interference-based spherical nucleic acids (SNAs), which consist of gold nanoparticle cores covalently conjugated with radially oriented and densely packed small interfering RNA (siRNA) oligonucleotides. On the basis of previous preclinical evaluation, we conducted toxicology and toxicokinetic studies in nonhuman primates and a single-arm, open-label phase 0 first-in-human trial (NCT03020017) to determine safety, pharmacokinetics, intratumoral accumulation and gene-suppressive activity of systemically administered SNAs carrying siRNA specific for the GBM oncogene Bcl2Like12 (Bcl2L12). Patients with recurrent GBM were treated with intravenous administration of siBcl2L12-SNAs (drug moniker: NU-0129), at a dose corresponding to 1/50th of the no-observed-adverse-event level, followed by tumor resection. Safety assessment revealed no grade 4 or 5 treatment-related toxicities. Inductively coupled plasma mass spectrometry, x-ray fluorescence microscopy, and silver staining of resected GBM tissue demonstrated that intravenously administered SNAs reached patient tumors, with gold enrichment observed in the tumor-associated endothelium, macrophages, and tumor cells. NU-0129 uptake into glioma cells correlated with a reduction in tumor-associated Bcl2L12 protein expression, as indicated by comparison of matched primary tumor and NU-0129-treated recurrent tumor. Our results establish SNA nanoconjugates as a potential brain-penetrant precision medicine approach for the systemic treatment of GBM.

Impact of p53, HIF1a, Ki-67, CA-9, and GLUT1 Expression on Treatment Outcomes in Locally Advanced Cervical Cancer Patients Treated With Definitive Chemoradiation Therapy.

PURPOSE/OBJECTIVE: The objective of this study was to assess the association between pretreatment p53, hypoxia inducible factor 1a (HIF1a), Ki-67, carbonic anhydrase-9 (CA-9), and glucose transporter 1 (GLUT1) expression in locally advanced cervical cancer patients treated definitively with concurrent chemoradiation therapy (CRT) and treatment outcomes including overall survival (OS), progression-free survival (PFS), local-regional control (LC), and distant metastases-free survival (DMFS). PATIENTS AND METHODS: Twenty-eight patients treated definitively and consecutively for cervical cancer with CRT had p53, HIF1a, Ki-67, CA-9, and GLUT1 protein expression assessed and scored semiquantitatively by 3 pathologists, blinded to the treatment outcomes. Outcomes were stratified by p53 (H-score: <15 vs. ≥15), HIF1a (H-score: <95 vs. ≥95), Ki-67 (labeling index <41% vs. ≥41%), CA-9 (H-score: <15 vs. ≥15), and GLUT1 (H-score: <175 vs. ≥175) expression. OS, PFS, LC, and DMFS rates were calculated using the Kaplan-Meier method, and differences between groups were evaluated by the log-rank test. RESULTS: Notable clinical characteristics of the cohort included median age of 51 years (range: 32 to 74 y), FIGO stage IIB disease (57.2%), clinical node-negative disease (64.3%), squamous cell carcinoma (89.3%), and adenocarcinoma (10.7%). Treatment outcomes included 5-year OS (57.2%), PFS (48.1%), LC (72.1%), and DMFS (62.9%). For HIF1a H-score <95 and ≥95, the 5-year OS (52.0% and 68.4%, P=0.58), PFS (53.0% and 40.9%, P=0.75), LC (71.6% and 68.2%, P=0.92), and DMFS (59.7% and 52.0%, P=0.91) were not significantly different. For Ki-67 labeling index <41% and ≥41%, the 5-year OS (44.9% and 66.6%, P=0.35), PFS (38.9% and 55.4%, P=0.53), LC (57.7% and 85.7%, P=0.22), and DMFS (67.3% and 61.0%, P=0.94) were not significantly different. For CA-9 H-score <15 and ≥15, the 5-year OS (54.4% and 66.7%, P=0.39), PFS (57.3% and 40.0%, P=0.87), LC (70.0% and 70.0%, P=0.95), and DMFS (70.0% and 46.7%, P=0.94) were not significantly different. For GLUT1 H-score <175 and ≥175, the 5-year OS (43.6% and 43.6%, P=0.32), PFS (55.6% and 49.5%, P=0.72), LC (72.9% and 71.5%, P=0.97), and DMFS (62.5% and 59.6%, P=0.76) were not significantly different. For p53, H-score <15 and ≥15, the 5-year OS (62% and 53%), PFS (63% and 30.3%), LC (87.5% and 52%), and DMFS (79.6% and 41.6%). CONCLUSIONS: In this study population, HIF1a, Ki-67, CA-9, and GLUT1 expression did not predict treatment response or outcomes in locally advanced cervical cancer patients treated definitively with CRT. There was a nonstatistically significant trend towards worse outcomes with p53 expression.

Effects of low dose and low dose rate low linear energy transfer radiation on animals - review of recent studies relevant for carcinogenesis.

Purpose: Carcinogenic effects of radiation are often assumed to be universally understood, more often than, for example, carcinogenic effects of many different chemicals. This in turn leads to an assumption that any dose of radiation, delivered at any dose rate, poses a serious health challenge. This remains an issue of dispute and low dose radiation research is focused on understanding whether these exposures contribute to cancer incidence. This review is focused on the low linear energy transfer (low LET) radiation exposures for which the data is the most abundant in recent years. Materials and methods: Review of the literature between 2008 and today, highlighting some of the most diverse studies in low dose research. Results: Low dose and low dose rate, low LET ionizing radiation animal studies suggest that the effects of exposure very much depend on animal genotype and health status.Conclusions: Only the integration of all of the data from different models and studies will lead to a fuller understanding of low dose radiation effects. Therefore, we hope to see an increase in international archival efforts and exchange of raw data information opening the possibilities for new types of meta analyses.

Low-Dose Radiation Therapy (LDRT) for COVID-19: Benefits or Risks?

The limited impact of treatments for COVID-19 has stimulated several phase 1 clinical trials of whole-lung low-dose radiation therapy (LDRT; 0.3-1.5 Gy) that are now progressing to phase 2 randomized trials worldwide. This novel but unconventional use of radiation to treat COVID-19 prompted the National Cancer Institute, National Council on Radiation Protection and Measurements and National Institute of Allergy and Infectious Diseases to convene a workshop involving a diverse group of experts in radiation oncology, radiobiology, virology, immunology, radiation protection and public health policy. The workshop was held to discuss the mechanistic underpinnings, rationale, and preclinical and emerging clinical studies, and to develop a general framework for use in clinical studies. Without refuting or endorsing LDRT as a treatment for COVID-19, the purpose of the workshop and this review is to provide guidance to clinicians and researchers who plan to conduct preclinical and clinical studies, given the limited available evidence on its safety and efficacy.

Dual blockade of CD47 and HER2 eliminates radioresistant breast cancer cells.

Although the efficacy of cancer radiotherapy (RT) can be enhanced by targeted immunotherapy, the immunosuppressive factors induced by radiation on tumor cells remain to be identified. Here, we report that CD47-mediated anti-phagocytosis is concurrently upregulated with HER2 in radioresistant breast cancer (BC) cells and RT-treated mouse syngeneic BC. Co-expression of both receptors is more frequently detected in recurrent BC patients with poor prognosis. CD47 is upregulated preferentially in HER2-expressing cells, and blocking CD47 or HER2 reduces both receptors with diminished clonogenicity and augmented phagocytosis. CRISPR-mediated CD47 and HER2 dual knockouts not only inhibit clonogenicity but also enhance macrophage-mediated attack. Dual antibody of both receptors synergizes with RT in control of syngeneic mouse breast tumor. These results provide the evidence that aggressive behavior of radioresistant BC is caused by CD47-mediated anti-phagocytosis conjugated with HER2-prompted proliferation. Dual blockade of CD47 and HER2 is suggested to eliminate resistant cancer cells in BC radiotherapy.

A combinatorial approach of a polypharmacological adjuvant 2-deoxy-D-glucose with low dose radiation therapy to quell the cytokine storm in COVID-19 management.

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a pandemic disease and is the major cause of deaths worldwide. The clinical complexities (inflammation, cytokine storm, and multi-organ dysfunction) associated with COVID-19 poses constraints to effective management of critically ill COVID-19 patients. Low dose radiation therapy (LDRT) has been evaluated as a potential therapeutic modality for COVID-19 pneumonia. However, due to heterogeneity in disease manifestation and inter-individual variations, effective planning for LDRT is limited for this large-scale event. 2-deoxy-D-glucose (2-DG) has emerged as a polypharmacological agent for COVID-19 treatment due to its effects on the glycolytic pathway, anti-inflammatory action, and interaction with viral proteins. We suggest that 2-DG will be a potential adjuvant to enhance the efficacy of LDRT in the treatment of COVID-19 pneumonia. Withal, azido analog of 2-DG, 2-azido-2-DG can produce rapid catastrophic oxidative stress and quell the cytokine storm in critically ill COVID-19 patients.