Extracellular Vesicles in Modifying the Effects of Ionizing Radiation

Gamma irradiation-engineered macrophage-derived exosomes as potential immunomodulatory therapeutic agents

The modulation of macrophage polarization is a promising strategy for maintaining homeostasis and improving innate and adaptive immunity. Low-dose ionizing radiation has been implicated in macrophage immunomodulatory responses. However, studies on the relationship between exosomes and regulation of macrophage polarization induced by ionizing radiation are limited. Therefore, this study investigated the alterations in macrophages and exosomes induced by gamma irradiation and elucidated the underlying mechanisms. We used the mouse macrophage cell line RAW 264.7 to generate macrophages and performed western blot, quantitative reverse transcription-PCR, and gene ontology analyses to elucidate the molecular profiles of macrophage-derived exosomes under varying treatment conditions, including 10 Gy gamma irradiation. Exosomes isolated from gamma-irradiated M1 macrophages exhibited an enhanced M1 phenotype. Irradiation induced the activation of NF-κB and NLRP3 signaling in M1 macrophages, thereby promoting the expression of pro-inflammatory cytokines. Cytokine expression was also upregulated in gamma-irradiated M1 macrophage-released exosomes. Therefore, gamma irradiation has a remarkable effect on the immunomodulatory mechanisms and cytokine profiles of gamma-irradiated M1 macrophage-derived exosomes, and represents a potential immunotherapeutic modality.

Radiation-induced exosomes promote oral squamous cell carcinoma progression via enhancing SLC1A5-glutamine metabolism

BACKGROUND

Radiotherapy (RT) can drive cancer cells to enter a state of cellular senescence in which cells can secrete senescence-associated secretory phenotype (SASP) and produce small extracellular vesicles (sEVs) to interact with cells in the tumor microenvironment (TME). Tumor-derived sEVs that are taken up by recipient cells contribute to cancer cell metabolic plasticity, resistance to anticancer therapy, and adaptation to the TME. However, how radiation-induced sEVs support oral squamous cell carcinoma (OSCC) progression remains unclear.

METHODS

Beta-galactosidase staining and SASP mRNA expression analysis were used to evaluate the senescence-associated activity of OSCC cells after irradiation. Nanoparticle tracking analysis was performed to identify radiation-induced sEVs. Liquid chromatography-tandem mass spectrometry (LC-MS) was used to explore changes in the levels of proteins in radiation-induced sEVs. Cell Counting Kit-8 and colony formation assays were performed to investigate the function of radiation-induced SASP and sEVs in vitro. A xenograft tumor model was established to investigate the functions of radiation-induced sEVs and V-9302 in vivo as well as the underlying mechanisms. Bioinformatics analysis was performed to determine the relationship between glutamine metabolism and OSCC recurrence.

RESULTS

We determined that the radiation-induced SASP triggered OSCC cell proliferation. Additionally, radiation-induced sEVs exacerbated OSCC cell malignancy. LC-MS/MS and bioinformatics analyses revealed that SLC1A5, which is a cellular receptor that participates in glutamine uptake, was significantly enriched in radiation-induced sEVs. In vitro and in vivo, inhibiting SLC1A5 could block the oncogenic effects of radiation-induced sEVs in OSCC.

CONCLUSION

Radiation-induced sEVs might promote the proliferation of unirradiated cancer cells by enhancing glutamine metabolism; this might be a novel molecular mechanism underlying radiation resistance in OSCC patients.

New approach methodologies to enhance human health risk assessment of immunotoxic properties of chemicals - a PARC (Partnership for the Assessment of Risk from Chemicals) project

As a complex system governing and interconnecting numerous functions within the human body, the immune system is unsurprisingly susceptible to the impact of toxic chemicals. Toxicants can influence the immune system through a multitude of mechanisms, resulting in immunosuppression, hypersensitivity, increased risk of autoimmune diseases and cancer development. At present, the regulatory assessment of the immunotoxicity of chemicals relies heavily on rodent models and a limited number of Organisation for Economic Co-operation and Development (OECD) test guidelines, which only capture a fraction of potential toxic properties. Due to this limitation, various authorities, including the World Health Organization and the European Food Safety Authority have highlighted the need for the development of novel approaches without the use of animals for immunotoxicity testing of chemicals. In this paper, we present a concise overview of ongoing efforts dedicated to developing and standardizing methodologies for a comprehensive characterization of the immunotoxic effects of chemicals, which are performed under the EU-funded Partnership for the Assessment of Risk from Chemicals (PARC).

The influence of radiation-induced bystander effect in osteoblasts mediated by plasma-derived extracellular vesicles (EVs)

OBJECTIVES

Head and neck tumor patients may develop post-radiotherapy diseases after radiotherapy treatment. And radiotherapy can elicit radiation-induced bystander effect, wherein extracellular vesicles (EVs) play a crucial role. For normal parts of the body that have not been directly irradiated, the effect of EVs on them needs to be further explored. This study aims to investigate the functions of plasma-derived EVs in regulating normal osteoblasts during radiation-induced bystander effects.

METHODS AND MATERIALS

Rat plasma-derived EVs were isolated and identified firstly, followed by an evaluation of their intracellular biological effects on normal osteoblasts in vitro. Transcriptome sequencing analysis and confirmations were performed to identify potential mechanisms.

RESULTS

Irradiated plasma-derived EVs were found to enhance osteoblast proliferation, migration, and cell cycle progression, concurrently suppressing the expression of osteogenesis-related genes and proteins. Furthermore, these EVs attenuated the expression of osteogenesis and oxidative stress resistance related genes, while upregulating the PI3K-AKT pathway and intracellular reactive oxygen species in osteoblasts.

CONCLUSIONS

Irradiated plasma-derived EVs could alter the biological effects in osteoblasts, which is closely associated with the levels of GPX1 and the PI3K-AKT signaling pathway. This suggests that plasma-derived EVs serve as a crucial factor contributing to radiation-induced bystander effect in osteoblasts.

Indirect effects of interference of two emerging environmental contaminants on cell health: Radiofrequency radiation and gold nanoparticles

BACKGROUND

The global need for wireless technologies is growing rapidly. So, we have been exposed to a new type of environmental pollution: radiofrequency radiation (RFR). Recent studies have shown that RFR can cause not only direct effects but also indirect or non-targeted effects such as the bystander effect (BE). In this study, we investigated the BE induced by RFR in the present of gold nanoparticles (GNP). Moreover, we studied the expression of cyclooxygenase-2 (COX-2).

METHODS

Non-toxic dose of 15-nm GNP was used to treat the Chinese Hamster Ovary (CHO) cells. After 48 h of incubation, cells were exposed to 900 MHz GSM RFR for 24 h. Then we collected the cell culture medium of these cells (conditioned culture medium, CCM) and transferred it to new cells (bystander cells). Cell deaths, DNA breaks, oxidative stress and COX-2 expression were analyzed in all groups.

RESULTS

The results showed that RFR increased metabolic death in cells treated with GNP. Inversely, the colony formation ability was reduced in bystander cells and RFR exposed cells either in the presence or absence of GNP. Also, the level of reactive oxygen species (ROS) in GNP treated cells showed a significant reduction compared to those of untreated cells. However, RFR-induced DNA breaks and the frequencies of micronuclei (MN) were not significantly affected by GNP. The expression of COX-2 mRNA increased in RFR GNP treated cells, but the difference was not significant.

CONCLUSION

Our results for the first time indicated that RFR induce indirect effects in the presence of GNP. However, the molecular mediators of these effects differ from those in the absence of GNP. Also, to our knowledge, this is the first study to show that COX-2 is not involved in the bystander effect induced by 900 MHz RFR.

Effect of radiotherapy on the DNA cargo and cellular uptake mechanisms of extracellular vesicles

In the past decades, plenty of evidence has gathered pointing to the role of extracellular vesicles (EVs) secreted by irradiated cells in the development of radiation-induced non-targeted effects. EVs are complex natural structures composed of a phospholipid bilayer which are secreted by virtually all cells and carry bioactive molecules. They can travel certain distances in the body before being taken up by recipient cells. In this review we discuss the role and fate of EVs in tumor cells and highlight the importance of DNA specimens in EVs cargo in the context of radiotherapy. The effect of EVs depends on their cargo, which reflects physiological and pathological conditions of donor cell types, but also depends on the mode of EV uptake and mechanisms involved in the route of EV internalization. While the secretion and cargo of EVs from irradiated cells has been extensively studied in recent years, their uptake is much less understood. In this review, we will focus on recent knowledge regarding the EV uptake of cancer cells and the effect of radiation in this process.

Proton Compared to X-Irradiation Induces Different Protein Profiles in Oral Cancer Cells and Their Derived Extracellular Vesicles

Extracellular vesicles (EVs) are membrane-bound particles released from cells, and their cargo can alter the function of recipient cells. EVs from X-irradiated cells have been shown to play a likely role in non-targeted effects. However, EVs derived from proton irradiated cells have not yet been studied. We aimed to investigate the proteome of EVs and their cell of origin after proton or X-irradiation. The EVs were derived from a human oral squamous cell carcinoma (OSCC) cell line exposed to 0, 4, or 8 Gy from either protons or X-rays. The EVs and irradiated OSCC cells underwent liquid chromatography-mass spectrometry for protein identification. Interestingly, we found different protein profiles both in the EVs and in the OSCC cells after proton irradiation compared to X-irradiation. In the EVs, we found that protons cause a downregulation of proteins involved in cell growth and DNA damage response compared to X-rays. In the OSCC cells, proton and X-irradiation induced dissimilar cell death pathways and distinct DNA damage repair systems. These results are of potential importance for understanding how non-targeted effects in normal tissue can be limited and for future implementation of proton therapy in the clinic.

Effect of environmental exposures on cancer risk: Emerging role of non-coding RNA shuttled by extracellular vesicles

Environmental and lifestyle exposures have a huge impact on cancer risk; nevertheless, the biological mechanisms underlying this association remain poorly understood. Extracellular vesicles (EVs) are membrane-enclosed particles actively released by all living cells, which play a key role in intercellular communication. EVs transport a variegate cargo of biomolecules, including non-coding RNA (ncRNA), which are well-known regulators of gene expression. Once delivered to recipient cells, EV-borne ncRNAs modulate a plethora of cancer-related biological processes, including cell proliferation, differentiation, and motility. In addition, the ncRNA content of EVs can be altered in response to outer stimuli. Such changes can occur either as an active attempt to adapt to the changing environment or as an uncontrolled consequence of cell homeostasis loss. In either case, such environmentally-driven alterations in EV ncRNA might affect the complex crosstalk between malignant cells and the tumor microenvironment, thus modulating the risk of cancer initiation and progression. In this review, we summarize the current knowledge about EV ncRNAs at the interface between environmental and lifestyle determinants and cancer. In particular, we focus on the effect of smoking, air and water pollution, diet, exercise, and electromagnetic radiation. In addition, we have conducted a bioinformatic analysis to investigate the biological functions of the genes targeted by environmentally-regulated EV microRNAs. Overall, we draw a comprehensive picture of the role of EV ncRNA at the interface between external factors and cancer, which could be of great interest to the development of novel strategies for cancer prevention, diagnosis, and therapy.

Involvement of extracellular vesicles in the progression, diagnosis, treatment, and prevention of whole-body ionizing radiation-induced immune dysfunction

Acute radiation syndrome (ARS) develops after exposure to high doses of ionizing radiation and features immune suppression and organ failure. Currently, there are no diagnostics to identify the occurrence or severity of exposure and there are limited treatments and preventative strategies to mitigate ARS. Extracellular vesicles (EVs) are mediators of intercellular communication that contribute to immune dysfunction across many diseases. We investigated if EV cargo can identify whole body irradiation (WBIR) exposure and if EVs promote ARS immune dysfunction. We hypothesized that beneficial EVs derived from mesenchymal stem cells (MSC-EVs) would blunt ARS immune dysfunction and might serve as prophylactic radioprotectants. Mice received WBIR (2 or 9 Gy) with assessment of EVs at 3 and 7 days after exposure. LC-MS/MS proteomic analysis of WBIR-EVs found dose-related changes as well as candidate proteins that were increased with both doses and timepoints (34 total) such as Thromboxane-A Synthase and lymphocyte cytosolic protein 2. Suprabasin and Sarcalumenin were increased only after 9 Gy suggesting these proteins may indicate high dose/lethal exposure. Analysis of EV miRNAs identified miR-376 and miR-136, which were increased up to 200- and 60-fold respectively by both doses of WBIR and select miRNAs such as miR-1839 and miR-664 were increased only with 9 Gy. WBIR-EVs (9 Gy) were biologically active and blunted immune responses to LPS in RAW264.7 macrophages, inhibiting canonical signaling pathways associated with wound healing and phagosome formation. When given 3 days after exposure, MSC-EVs slightly modified immune gene expression changes in the spleens of mice in response to WBIR and in a combined radiation plus burn injury exposure (RCI). MSC-EVs normalized the expression of certain key immune genes such as NFκBia and Cxcr4 (WBIR), Map4k1, Ccr9 and Cxcl12 (RCI) and lowered plasma TNFα cytokine levels after RCI. When given prophylactically (24 and 3 hours before exposure), MSC-EVs prolonged survival to the 9 Gy lethal exposure. Thus, EVs are important participants in ARS. EV cargo might be used to diagnose WBIR exposure, and MSC-EVs might serve as radioprotectants to blunt the impact of toxic radiation exposure.

Plant-derived nanoparticles and plant virus nanoparticles: Bioactivity, health management, and delivery potential

Natural plants have acquired an increasing attention in biomedical research. Recent studies have revealed that plant-derived nanoparticles (PDNPs), which are nano-sized membrane vesicles released by plants, are one of the important material bases for the health promotion of natural plants. A great deal of research in this field has focused on nanoparticles derived from fresh vegetables and fruits. Generally, PDNPs contain lipids, proteins, nucleic acids, and other active small molecules and exhibit unique biological regulatory activity and editability. Specifically, they have emerged as important mediators of intercellular communication, and thus, are potentially suitable for therapeutic purposes. In this review, PDNPs were extensively explored; by evaluating them systematically starting from the origin and isolation, toward their characteristics, including morphological compositions, biological functions, and delivery potentials, as well as distinguishing them from plant-derived exosomes and highlighting the limitations of the current research. Meanwhile, we elucidated the variations in PDNPs infected by pathogenic microorganisms and emphasized on the biological functions and characteristics of plant virus nanoparticles. After clarifying these problems, it is beneficial to further research on PDNPs in the future and develop their clinical application value.

Immunomodulatory effects of targeted radionuclide therapy

It is now clear that conventional radiation therapy can reinstate cell death immunogenicity. Recent preclinical data indicate that targeted radionuclide therapy that irradiate tumors at continuous low dose rate also can elicit immunostimulatory effects and represents a promising strategy to circumvent immune checkpoint inhibitor resistance. In this perspective, we discuss the accumulating preclinical and clinical data suggesting that activation of the immune system through the cGAS-STING axis and the release of extracellular vesicles by irradiated cells, participate to this antitumor immunity. This should need to be considered for adapting clinical practices to state of the art of the radiobiology and to increase targeted radionuclide therapy effectiveness.

Meet changes with constancy: Defence, antagonism, recovery, and immunity roles of extracellular vesicles in confronting SARS-CoV-2

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has wrought havoc on the world economy and people's daily lives. The inability to comprehensively control COVID-19 is due to the difficulty of early and timely diagnosis, the lack of effective therapeutic drugs, and the limited effectiveness of vaccines. The body contains billions of extracellular vesicles (EVs), which have shown remarkable potential in disease diagnosis, drug development, and vaccine carriers. Recently, increasing evidence has indicated that EVs may participate or assist the body in defence, antagonism, recovery and acquired immunity against SARS-CoV-2. On the one hand, intercepting and decrypting the general intelligence carried in circulating EVs from COVID-19 patients will provide an important hint for diagnosis and treatment; on the other hand, engineered EVs modified by gene editing in the laboratory will amplify the effectiveness of inhibiting infection, replication and destruction of ever-mutating SARS-CoV-2, facilitating tissue repair and making a better vaccine. To comprehensively understand the interaction between EVs and SARS-CoV-2, providing new insights to overcome some difficulties in the diagnosis, prevention and treatment of COVID-19, we conducted a rounded review in this area. We also explain numerous critical challenges that these tactics face before they enter the clinic, and this work will provide previous 'meet change with constancy' lessons for responding to future similar public health disasters. Extracellular vesicles (EVs) provide a 'meet changes with constancy' strategy to combat SARS-CoV-2 that spans defence, antagonism, recovery, and acquired immunity. Targets for COVID-19 diagnosis, therapy, and prevention of progression may be found by capture of the message decoding in circulating EVs. Engineered and biomimetic EVs can boost effects of the natural EVs, especially anti-SARS-CoV-2, targeted repair of damaged tissue, and improvement of vaccine efficacy.

Out-of-field effects: lessons learned from partial body exposure

Partial body exposure and inhomogeneous dose delivery are features of the majority of medical and occupational exposure situations. However, mounting evidence indicates that the effects of partial body exposure are not limited to the irradiated area but also have systemic effects that are propagated outside the irradiated field. It was the aim of the "Partial body exposure" session within the MELODI workshop 2020 to discuss recent developments and insights into this field by covering clinical, epidemiological, dosimetric as well as mechanistic aspects. Especially the impact of out-of-field effects on dysfunctions of immune cells, cardiovascular diseases and effects on the brain were debated. The presentations at the workshop acknowledged the relevance of out-of-field effects as components of the cellular and organismal radiation response. Furthermore, their importance for the understanding of radiation-induced pathologies, for the discovery of early disease biomarkers and for the identification of high-risk organs after inhomogeneous exposure was emphasized. With the rapid advancement of clinical treatment modalities, including new dose rates and distributions a better understanding of individual health risk is urgently needed. To achieve this, a deeper mechanistic understanding of out-of-field effects in close connection to improved modelling was suggested as priorities for future research. This will support the amelioration of risk models and the personalization of risk assessments for cancer and non-cancer effects after partial body irradiation.

cGAS/cGAMP/STING signal propagation in the tumor microenvironment: key role for myeloid cells in antitumor immunity

Cyclic GMP-AMP synthase (cGAS), second messenger 2'3'-cyclic GMP-AMP (cGAMP) and stimulator of interferon genes (STING) are fundamental for sensing cytoplasmic double stranded DNA. Radiotherapy treatment induces large amounts of nuclear and mitochondrial DNA damage and results in the presence of DNA fragments in the cytoplasm, activating the cGAS/STING pathway. Triggering of the cGAS/STING pathway in the tumor microenvironment (TME) results in the production of type I interferons (IFNs). Type I IFNs are crucial for an effective antitumor defense, with myeloid cells as key players. Many questions remain on how these myeloid cells are activated and in which cells (tumor versus myeloid) in the TME the signaling pathway is initiated. The significance of cGAS/STING signaling in the onco-immunology field is being recognized, emphasized by the frequent occurrence of mutations in or silencing of genes in this pathway. We here review several mechanisms of cGAS/STING signal propagation in the TME, focusing on tumor cells and myeloid cells. Cell-cell contact-dependent interactions facilitate the transfer of tumor-derived DNA and cGAMP. Alternatively, transport routes via the extracellular space such as extracellular vesicles, and channel-mediated cGAMP transfer to and from the extracellular space contribute to propagation of cGAS/STING signal mediators DNA and cGAMP. Finally, we discuss regulation of extracellular cGAMP. Altogether, we provide a comprehensive overview of cGAS/cGAMP/STING signal propagation from tumor to myeloid cells in the TME, revealing novel targets for combinatorial treatment approaches with conventional anticancer therapies like radiotherapy.

Medical management of acute radiation syndrome

Acute radiation syndrome (ARS) is a clinical syndrome involving four organ systems, resulting in the hematopoietic syndrome (HS), gastrointestinal subsyndrome (GIS), neurovascular subsyndrome (NVS) and cutaneous subsyndrome (CS). Since few healthcare providers have seen an ARS case, evidence-based recommendations are needed to guide medical management in a mass casualty scenario. The authors reviewed recommendations from evidence-based and narrative reviews by expert consultants to the World Health Organisation (WHO), a subsequent review of published HS cases, and infectious disease guidelines for management of febrile neutropenia. The WHO Consultancy applied a rigorous grading system to evaluate treatment strategies described in published ARS cases as of 2009, strategies to manage HS in unirradiated persons, results of ARS studies in animal models of ARS, and recommendations of prior expert panels. Major findings for HS were (a) no randomised controlled studies have been performed, (b) data are restricted by the lack of comparator groups, and (c) reports of countermeasures for management of injury to non-hematopoietic organs are often incomplete. Strength of recommendations ranged from strong to weak. Countermeasures of potential benefit include cytokines and for a subgroup of HS patients, hematopoietic stem cell transplantation. These recommendations did not change in a subsequent analysis of HS cases. Recommendations also included fluoroquinolones, bowel decontamination, serotonin receptor antagonists, loperamide and enteral nutrition for GIS; supportive care for NVS; and topical steroids, antihistamines and antibiotics, and surgical excision/grafting for CS. Also reviewed are critical care management guidelines, the role of mesenchymal stem cells for CS, the potential of a platelet-stimulating cytokine for HS, and the author's approach to clinical management of microbial infections associated with ARS based on published guidelines of infectious disease experts. Today's management of HS is supported by evidence-based guidelines. Management of non-HS subsyndromes is supported by a narrative review of the literature and recommendations of infectious disease societies.

Emergence of Edible Plant-Derived Nanovesicles as Functional Food Components and Nanocarriers for Therapeutics Delivery: Potentials in Human Health and Disease

Extracellular vesicles (EVs) are a highly heterogeneous population of membranous particles that are secreted by almost all types of cells across different domains of life, including plants. In recent years, studies on plant-derived nanovesicles (PDNVs) showed that they could modulate metabolic reactions of the recipient cells, affecting (patho)physiology with health benefits in a trans-kingdom manner. In addition to its bioactivity, PDNV has advantages over conventional nanocarriers, making its application promising for therapeutics delivery. Here, we discuss the characteristics of PDNV and highlight up-to-date pre-clinical and clinical evidence, focusing on therapeutic application.

The Footprint of Exosomes in the Radiation-Induced Bystander Effects

Radiation therapy is widely used as the primary treatment option for several cancer types. However, radiation therapy is a nonspecific method and associated with significant challenges such as radioresistance and non-targeted effects. The radiation-induced non-targeted effects on nonirradiated cells nearby are known as bystander effects, while effects far from the ionising radiation-exposed cells are known as abscopal effects. These effects are presented as a consequence of intercellular communications. Therefore, a better understanding of the involved intercellular signals may bring promising new strategies for radiation risk assessment and potential targets for developing novel radiotherapy strategies. Recent studies indicate that radiation-derived extracellular vesicles, particularly exosomes, play a vital role in intercellular communications and may result in radioresistance and non-targeted effects. This review describes exosome biology, intercellular interactions, and response to different environmental stressors and diseases, and focuses on their role as functional mediators in inducing radiation-induced bystander effect (RIBE).

The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment

The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

The Physical Chemistry and Chemical Physics Section (PCCP Section) is one of the youngest among the sections of the International Journal of Molecular Sciences (IJMS)—the year 2021 will only mark three years since its inception [...]

Internalized Nanoceria Modify the Radiation-Sensitivity Profile of MDA MB231 Breast Carcinoma Cells

Owing to its unique redox properties, cerium oxide (nanoceria) nanoparticles have been shown to confer either radiosensitization or radioprotection to human cells. We investigated nanoceria's ability to modify cellular health and reactive oxygen species (ROS) at various absorbed doses (Gray) of ionizing radiation in MDA-MB231 breast carcinoma cells. We used transmission electron microscopy to visualize the uptake and compartmental localization of nanoceria within cells at various treatment concentrations. The effects on apoptosis and other cellular health parameters were assessed using confocal fluorescence imaging and flow cytometry without and with various absorbed doses of ionizing radiation, along with intracellular ROS levels. Our results showed that nanoceria were taken up into cells mainly by macropinocytosis and segregated into concentration-dependent large aggregates in macropinosomes. Confocal imaging and flow cytometry data showed an overall decrease in apoptotic cell populations in proportion to increasing nanoparticle concentrations. This increase in cellular health was observed with a corresponding reduction in ROS at all tested absorbed doses. Moreover, this effect appeared pronounced at lower doses compared to unirradiated or untreated populations. In conclusion, internalized nanoceria confers radioprotection with a corresponding decrease in ROS in MDA-MB231 cells, and this property confers significant perils and opportunities when utilized in the context of radiotherapy.

Molecular Mechanisms of Mesenchymal Stem Cell-Based Therapy in Acute Kidney Injury

Acute kidney injury (AKI) causes a lot of harm to human health but is treated by only supportive therapy in most cases. Recent evidence shows that mesenchymal stem cells (MSCs) benefit kidney regeneration through releasing paracrine factors and extracellular vesicles (EVs) to the recipient kidney cells and are considered to be promising cellular therapy for AKI. To develop more efficient, precise therapies for AKI, we review the therapeutic mechanism of MSCs and MSC-derived EVs in AKI and look for a better understanding of molecular signaling and cellular communication between donor MSCs and recipient kidney cells. We also review recent clinical trials of MSC-EVs in AKI. This review summarizes the molecular mechanisms of MSCs' therapeutic effects on kidney regeneration, expecting to comprehensively facilitate future clinical application for treating AKI.

Functional intersections between extracellular vesicles and oncolytic therapies

Minimally invasive focal therapies for nonviral oncolysis are a cornerstone of cancer therapeutics. Our ability to optimally deploy oncolytic therapies and identify synergistic combination approaches requires a deeper understanding of elicited biological responses. Extracellular vesicles (EV), which orchestrate a variety of pathophysiological processes and have a critical role in the evolution of primary and disseminated tumors, are now known to be potently modulated by oncolytic focal therapies, such as radiotherapy, photodynamic therapy (PDT), and therapeutic ultrasound (TUS). In this review, we summarize the diverse impacts of the aforementioned therapeutic modalities on EV biology, and highlight the most recent advances in EV-based drug delivery systems leveraging these modalities.

Radiation-induced liver injury and hepatocyte senescence

Radiation-induced liver injury (RILI) is a major complication of radiotherapy during treatment for liver cancer and other upper abdominal malignant tumors that has poor pharmacological therapeutic options. A series of pathological changes can be induced by radiation. However, the underlying mechanism of RILI remains unclear. Radiation can induce cell damage via direct energy deposition or reactive free radical generation. Cellular senescence can be observed due to the DNA damage response (DDR) caused by radiation. The senescence-associated secretory phenotype (SASP) secreted from senescent cells can cause chronic inflammation and aggravate liver dysfunction for a long time. Oxidative stress further activates the signaling pathway of the inflammatory response and affects cellular metabolism. miRNAs clearly have differential expression after radiation treatment and take part in RILI development. This review aims to systematically profile the overall mechanism of RILI and the effects of radiation on hepatocyte senescence, laying foundations for the development of new therapies.

Role of Extracellular Vesicles in Compromising Cellular Resilience to Environmental Stressors

Extracellular vesicles (EVs), like exosomes, are nanosized membrane-enveloped vesicles containing different bioactive cargo, such as proteins, lipids, mRNA, miRNA, and other small regulatory RNAs. Cell-derived EVs, including EVs originating from stem cells, may capture components from damaged cells or cells impacted by therapeutic treatments. Interestingly, EVs derived from stem cells can be preconditioned to produce and secrete EVs with different therapeutic properties, particularly with respect to heat-shock proteins and other molecular cargo contents. This behavior is consistent with stem cells that also respond differently to various microenvironments. Heat-shock proteins play roles in cellular protection and mediate cellular resistance to radiotherapy, chemotherapy, and heat shock. This review highlights the possible roles EVs play in mediating cellular plasticity and survival when exposed to different physical and chemical stressors, with a special focus on the respiratory distress due to the air pollution.

The Emerging World of Membrane Vesicles: Functional Relevance, Theranostic Avenues and Tools for Investigating Membrane Function

Lipids are essential components of cell membranes and govern various membrane functions. Lipid organization within membrane plane dictates recruitment of specific proteins and lipids into distinct nanoclusters that initiate cellular signaling while modulating protein and lipid functions. In addition, one of the most versatile function of lipids is the formation of diverse lipid membrane vesicles for regulating various cellular processes including intracellular trafficking of molecular cargo. In this review, we focus on the various kinds of membrane vesicles in eukaryotes and bacteria, their biogenesis, and their multifaceted functional roles in cellular communication, host-pathogen interactions and biotechnological applications. We elaborate on how their distinct lipid composition of membrane vesicles compared to parent cells enables early and non-invasive diagnosis of cancer and tuberculosis, while inspiring vaccine development and drug delivery platforms. Finally, we discuss the use of membrane vesicles as excellent tools for investigating membrane lateral organization and protein sorting, which is otherwise challenging but extremely crucial for normal cellular functioning. We present current limitations in this field and how the same could be addressed to propel a fundamental and technology-oriented future for extracellular membrane vesicles.

Oxidative Stress and Gene Expression Modifications Mediated by Extracellular Vesicles: An In Vivo Study of the Radiation-Induced Bystander Effect

Radiation-induced bystander effect is a biological response in nonirradiated cells receiving signals from cells exposed to ionising radiation. The aim of this in vivo study was to analyse whether extracellular vesicles (EVs) originating from irradiated mice could induce modifications in the redox status and expression of radiation-response genes in bystander mice. C57BL/6 mice were whole-body irradiated with 0.1-Gy and 2-Gy X-rays, and EVs originating from mice irradiated with the same doses were injected into naïve, bystander mice. Lipid peroxidation in the spleen and plasma reactive oxygen metabolite (ROM) levels increased 24 h after irradiation with 2 Gy. The expression of antioxidant enzyme genes and inducible nitric oxide synthase 2 (iNOS2) decreased, while cell cycle arrest-, senescence- and apoptosis-related genes were upregulated after irradiation with 2 Gy. In bystander mice, no significant alterations were observed in lipid peroxidation or in the expression of genes connected to cell cycle arrest, senescence and apoptosis. However, there was a systemic increase in the circulating ROM level after an intravenous EV injection, and EVs originating from 2-Gy-irradiated mice caused a reduced expression of antioxidant enzyme genes and iNOS2 in bystander mice. In conclusion, we showed that ionising radiation-induced alterations in the cellular antioxidant system can be transmitted in vivo in a bystander manner through EVs originating from directly irradiated animals.

Radiation Response in the Tumour Microenvironment: Predictive Biomarkers and Future Perspectives

Radiotherapy (RT) is a primary treatment modality for a number of cancers, offering potentially curative outcomes. Despite its success, tumour cells can become resistant to RT, leading to disease recurrence. Components of the tumour microenvironment (TME) likely play an integral role in managing RT success or failure including infiltrating immune cells, the tumour vasculature and stroma. Furthermore, genomic profiling of the TME could identify predictive biomarkers or gene signatures indicative of RT response. In this review, we will discuss proposed mechanisms of radioresistance within the TME, biomarkers that may predict RT outcomes, and future perspectives on radiation treatment in the era of personalised medicine.

Ionizing Radiation-Induced Extracellular Vesicle Release Promotes AKT-Associated Survival Response in SH-SY5Y Neuroblastoma Cells

Radiation therapy is one of the most effective methods of tumor eradication; however, in some forms of neuroblastoma, radiation can increase the risk of secondary neoplasms, due to the ability of irradiated cells to transmit pro-survival signals to non-irradiated cells through vesicle secretion. The aims of this study were to characterize the vesicles released by the human neuroblastoma cell line SH-SY5Y following X-ray radiations and their ability to increase invasiveness in non-irradiated SH-SY5Y cells. We first purified the extracellular vesicles released by the SH-SY5Y cells following X-rays, and then determined their total amount, dimensions, membrane protein composition, and cellular uptake. We also examined the effects of these extracellular vesicles on viability, migration, and DNA damage in recipient SH-SY5Y cells. We found that exposure to X-rays increased the release of extracellular vesicles and altered their protein composition. These vesicles were readily uptaken by non-irradiated cells, inducing an increase in viability, migration, and radio-resistance. The same results were obtained in an MYCN-amplified SK-N-BE cell line. Our study demonstrates that vesicles released from irradiated neuroblastoma cells stimulate proliferation and invasiveness that correlate with the epithelial to mesenchymal transition in non-irradiated cells. Moreover, our results suggest that, at least in neuroblastomas, targeting the extracellular vesicles may represent a novel therapeutic approach to counteract the side effects associated with radiotherapy.

Cutaneous Radiation Injuries: Models, Assessment and Treatments

Many cases of human exposures to high-dose radiation have been documented, including individuals exposed during the detonation of atomic bombs in Hiroshima and Nagasaki, nuclear power plant disasters (e.g., Chernobyl), as well as industrial and medical accidents. For many of these exposures, injuries to the skin have been present and have played a significant role in the progression of the injuries and survivability from the radiation exposure. There are also instances of radiation-induced skin complications in routine clinical radiotherapy and radiation diagnostic imaging procedures. In response to the threat of a radiological or nuclear mass casualty incident, the U.S. Department of Health and Human Services tasked the National Institute of Allergy and Infectious Diseases (NIAID) with identifying and funding early- to mid-stage medical countermeasure (MCM) development to treat radiation-induced injuries, including those to the skin. To appropriately assess the severity of radiation-induced skin injuries and determine efficacy of different approaches to mitigate/treat them, it is necessary to develop animal models that appropriately simulate what is seen in humans who have been exposed. In addition, it is important to understand the techniques that are used in other clinical indications (e.g., thermal burns, diabetic ulcers, etc.) to accurately assess the extent of skin injury and progression of healing. For these reasons, the NIAID partnered with two other U.S. Government funding and regulatory agencies, the Biomedical Advanced Research and Development Authority (BARDA) and the Food and Drug Administration (FDA), to identify state-of-the-art methods in assessment of skin injuries, explore animal models to better understand radiation-induced cutaneous damage and investigate treatment approaches. A two-day workshop was convened in May 2019 highlighting talks from 28 subject matter experts across five scientific sessions. This report provides an overview of information that was presented and the subsequent guided discussions.

Reflectance structured illumination imaging of internalized cerium oxide nanoparticles modulating dose-dependent reactive oxygen species in breast cancer cells

Cerium oxide nanoparticles have been shown to sensitize cancer cells to radiation damage. Their unique redox properties confer excellent therapeutic potential by augmenting radiation dose with reactive oxygen species mediating bystander effects. Owing to its metallic properties, cerium oxide nanoparticles can be visualized inside cells using reflected light and optical sectioning. This can be advantageous in settings requiring none or minimal sample preparation and modification. We investigated the use of reflectance imaging for the detection of unmodified nanoceria in MDA MB231 breast cancer cells along with differential interference contrast imaging and fluorescent nuclear labeling. We also performed studies to evaluate the uptake capability, cellular toxicity and redox properties of nanocaria in these cells. Our results demonstrate that reflectance structured illumination imaging can effectively localize cerium oxide nanoparticles in breast cancer cells, and when combining with differential interference contrast and fluorescent cell label imaging, effective compartmental localization of the nanoparticles can be achieved. The total number of cells taking up the nanoparticles and the amount of nanoparticle uptake increased significantly in proportion to the dose, with no adverse effects on cell survival. Moreover, significant reduction in reactive oxygen species was also observed in proportion to increasing nanoceria concentrations attesting to its ability to modulate oxidative stress. In conclusion, this work serves as a pre-clinical scientific evaluation of the effective use of reflectance structured illumination imaging of cerium oxide nanoparticles in breast cancer cells and the safe use of these nanoparticles in MDA MB231 cells for further therapeutic applications.

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Internalized cerium oxide nanoparticles are imaged with reflected light in breast cancer cells for the first time.

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Cerium oxide nanoparticles demonstrated no toxicity in MDA MB231 breast cancer cells

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Cerium oxide nanoparticles modulated free radicals in MBA MB231 cells in a dose dependent manner