Exosome-packaged miR-1246 contributes to bystander DNA damage by targeting LIG4

The functional regulation between extracellular vesicles and the DNA damage responses

The DNA damage response (DDR) is a crucial regulatory mechanism for the survival of organisms, and irregularity of DDR may contribute to the development of various diseases, including tumors, making it is a prominent topic in therapeutic research. Extracellular vesicles (EVs), as important mediators of intercellular communication, have been extensively studied in recent years. Notably, an increasing number of studies have revealed a strong connection between DDR and EVs. On one hand, DNA damage affects the release of EVs and their compositional content; on the other hand, EVs can dictate cell survival or death by modulating DDR in both the parental and the recipient cells. This review outlines current progress in the inter-regulatory relationship between EVs and DDR, with special emphasis on the effects of EVs derived from various sources on DDR in recipient cells. In addition, the potential applications of EVs in research and tumor therapy are discussed.

Role of exosomes in modulating non-small cell lung cancer radiosensitivity

Non-small cell lung cancer (NSCLC) constitutes a significant proportion of lung cancer cases, and despite advancements in treatment modalities, radiotherapy resistance remains a substantial hurdle in effective cancer management. Exosomes, which are small vesicles secreted by cells, have emerged as pivotal players in intercellular communication and influence various biological processes, including cancer progression and the response to therapy. This review discusses the intricate role of exosomes in the modulation of NSCLC radiosensitivity. The paper focuses on NSCLC and highlights how tumor-derived exosomes contribute to radioresistance by enhancing DNA repair, modulating immune responses, and altering the tumor microenvironment. We further explore the potential of mesenchymal stem cell-derived exosomes to overcome radiotherapy resistance and their potential as biomarkers for predicting therapeutic outcomes. Understanding the mechanisms by which exosomes affect radiotherapy can provide new avenues for enhancing treatment efficacy and improving the survival rates of patients with NSCLC.

Serum exosomal miRNA promote glioma progression by targeting SOS1 via abscopal effect of radiation

INTRODUCTION

Local exposure to ionizing radiation (IR) can induce changes in biological processes in distant tissues and organs. Exosomes are nanoscale vesicles that transport biomolecules, mediate communication between cells and tissues, and can affect the abscopal effects of radiotherapy.

METHODS

Mice were treated with 8.0 Gy doses of chest and abdomen IR, after which serum samples were taken 24 h after exposure. Their serum exosomes were then isolated via ultracentrifugation and the small RNA portions were extracted for sequencing and bioinformatic analysis. Exosomes were injected intravenously into the mice to assess their ability to cross the blood-brain barrier (BBB). Glioma cells and glioma stem cells (GSCs) were examined for malignant biological behaviors, stemness, and tumorigenic capacity after co-culturing with different groups of exosomes.

RESULTS

We found that serum exosomes crossed the BBB in mice after local IR exposure-which induced decreases in the expression of BBB tight-junction proteins and increased brain endothelial cell apoptosis. Exosomes from the exposed groups promoted malignant biological behaviors, stemness, and tumorigenic capacity in glioma cells and GSCs by upregulating the expression of SOS1. Phospho-MEK1/2 and Phospho-ERK1/2, of the MAPK signaling pathway, were found to be up-regulated in cells that were co-cultured with the exposing groups of the exosomes. Further analyses demonstrated that differentially expressed levels of miR-93-5p in mouse serum exosomes regulated the cellular expression of SOS1.

CONCLUSION

Following local IR exposure, serum exosomes cross the BBB to promote the progression of distant gliomas. Exosomal microRNAs play an important role in this process.

Exosomes: Their role in the diagnosis, progression, metastasis, and treatment of glioblastoma

Exosomes are crucial for the growth and spread of glioblastomas, an aggressive form of brain cancer. These tiny vesicles play a crucial role in the activation of signaling pathways and intercellular communication. They can also transfer a variety of biomolecules such as proteins, lipids and nucleic acids from donor to recipient cells. Exosomes can influence the immune response by regulating the activity of immune cells, and they are crucial for the growth and metastasis of glioblastoma cells. In addition, exosomes contribute to drug resistance during treatment, which is a major obstacle in the treatment of glioblastoma. By studying them, the diagnosis and prognosis of glioblastoma can be improved. Due to their high biocompatibility and lack of toxicity, they have become an attractive option for drug delivery. The development of exosomes as carriers of specific therapeutic agents could overcome some of the obstacles to effective treatment of glioblastoma. In this review, we address the potential of exosomes for the treatment of glioblastoma and show how they can be modified for this purpose.

Hypoxic regulation of extracellular vesicles: Implications for cancer therapy

Extracellular vesicles (EVs) play a pivotal role in intercellular communication and have been implicated in cancer progression. Hypoxia, a pervasive hallmark of cancer, is known to regulate EV biogenesis and function. Hypoxic EVs contain a specific set of proteins, nucleic acids, lipids, and metabolites, capable of reprogramming the biology and fate of recipient cells. Enhancing the intrinsic therapeutic efficacy of EVs can be achieved by strategically modifying their structure and contents. Moreover, the use of EVs as drug delivery vehicles holds great promise for cancer treatment. However, various hurdles must be overcome to enable their clinical application as cancer therapeutics. In this review, we aim to discuss the current knowledge on the hypoxic regulation of EVs. Additionally, we will describe the underlying mechanisms by which EVs contribute to cancer progression in hypoxia and outline the progress and limitations of hypoxia-related EV therapeutics for cancer.

Exosomes in Cancer Progression and Therapy Resistance: Molecular Insights and Therapeutic Opportunities

The development of therapy resistance still represents a major hurdle in treating cancers, leading to impaired treatment success and increased patient morbidity. The establishment of minimally invasive liquid biopsies is a promising approach to improving the early diagnosis, as well as therapy monitoring, of solid tumors. Because of their manifold functions in the tumor microenvironment, tumor-associated small extracellular vesicles, referred to as exosomes, have become a subject of intense research. Besides their important roles in cancer progression, metastasis, and the immune response, it has been proposed that exosomes also contribute to the acquisition and transfer of therapy resistance, mainly by delivering functional proteins and RNAs, as well as facilitating the export of active drugs or functioning as extracellular decoys. Extensive research has focused on understanding the molecular mechanisms underlying the occurrence of resistance and translating these into strategies for early detection. With this review, we want to provide an overview of the current knowledge about the (patho-)biology of exosomes, as well as state-of-the-art methods of isolation and analysis. Furthermore, we highlight the role of exosomes in tumorigenesis and cancer treatment, where they can function as therapeutic agents, biomarkers, and/or targets. By focusing on their roles in therapy resistance, we will reveal new paths of exploiting exosomes for cancer diagnosis and treatment.

Double-strand DNA break repair: molecular mechanisms and therapeutic targets

Double-strand break (DSB), a significant DNA damage brought on by ionizing radiation, acts as an initiating signal in tumor radiotherapy, causing cancer cells death. The two primary pathways for DNA DSB repair in mammalian cells are nonhomologous end joining (NHEJ) and homologous recombination (HR), which cooperate and compete with one another to achieve effective repair. The DSB repair mechanism depends on numerous regulatory variables. DSB recognition and the recruitment of DNA repair components, for instance, depend on the MRE11-RAD50-NBS1 (MRN) complex and the Ku70/80 heterodimer/DNA-PKcs (DNA-PK) complex, whose control is crucial in determining the DSB repair pathway choice and efficiency of HR and NHEJ. In-depth elucidation on the DSB repair pathway's molecular mechanisms has greatly facilitated for creation of repair proteins or pathways-specific inhibitors to advance precise cancer therapy and boost the effectiveness of cancer radiotherapy. The architectures, roles, molecular processes, and inhibitors of significant target proteins in the DSB repair pathways are reviewed in this article. The strategy and application in cancer therapy are also discussed based on the advancement of inhibitors targeted DSB damage response and repair proteins.

P53-response circRNA_0006420 aggravates lung cancer radiotherapy resistance by promoting formation of HUR/PTBP1 complex

BACKGROUND

p53 wild-type lung cancer cells can develop radiation resistance. Circular RNA (circRNA) consists of a family of transcripts with exclusive structures. circRNA is critical in tumorigenesis and is a potential biomarker or therapeutic target. It is uncertain how circRNA expression and functions are regulated post-radiation in p53 wild-type cancer cells.

METHODS

A549 or H1299 cells were divided into p53-wt and p53-KO groups by CRISPR/Cas9; both groups were subjected to 4Gy ionizing radiation (IR: p53-wt-IR and p53-KO-IR). RNA-seq, CCK8, cell cycle, and other functional and mechanism experiments were performed in vivo. p53 gene knockout mice were generated to test the cell results in vitro.

RESULTS

circRNAs were found in differential groups. circRNA_0006420 (IRSense) was upregulated in p53-wt cells but had the same expression level as p53-KO cells after radiation, indicating that p53 silencing prevents its upregulation after IR. In the presence of p53, upregulated IRSense post-radiation induces G2/M arrest by regulating DNA damage repair (DDR) pathway-related proteins. Meanwhile, upregulated IRSense post-radiation aggravates the radiation-induced epithelial-mesenchymal transition (EMT). Interestingly, in the presence of p53, it promotes IRSense/HUR/PTBP1 complex formation resulting in the promotion of the radiation-induced EMT. Moreover, c-Jun regulates the upregulation of p53 transcription after radiation treatment. For these lung cancer cells with p53, upregulated IRSense aggravates lung cancer cell proliferation and increases radiation resistance by interacting with HUR (ElAV-like protein 1) and PTBP1 (polypyrimidine tract-binding protein 1) in the nucleus.

CONCLUSIONS

Lung cancer cells retaining p53 may upregulate circRNA_0006420 (IRSense) expression post radiation to form an IRSense/HUR/PTBP1 complex leading to radiotherapy resistance. This study furthers our understanding of the roles of circRNA in regulating the effect of radiotherapy and provides novel therapeutic avenues for effective clinical lung cancer therapies.

Recent Advances in Extracellular Vesicles in Amyotrophic Lateral Sclerosis and Emergent Perspectives

Amyotrophic lateral sclerosis (ALS) is a severe and incurable neurodegenerative disease characterized by the progressive death of motor neurons, leading to paralysis and death. It is a rare disease characterized by high patient-to-patient heterogeneity, which makes its study arduous and complex. Extracellular vesicles (EVs) have emerged as important players in the development of ALS. Thus, ALS phenotype-expressing cells can spread their abnormal bioactive cargo through the secretion of EVs, even in distant tissues. Importantly, owing to their nature and composition, EVs' formation and cargo can be exploited for better comprehension of this elusive disease and identification of novel biomarkers, as well as for potential therapeutic applications, such as those based on stem cell-derived exosomes. This review highlights recent advances in the identification of the role of EVs in ALS etiopathology and how EVs can be promising new therapeutic strategies.

Mesenchymal stem cell-derived exosomes attenuate DNA damage response induced by cisplatin and bleomycin

Stem cell-derived exosomes (SC-Exos) have been shown to protect cells from chemical-induced deoxyribonucleic acid (DNA) damage. However, there has been no systematic comparison of the efficacy of exosomes against different types of DNA damage. Therefore, in this study, we assessed the protective effect of exosomes derived from human embryonic stem cell-induced mesenchymal stem cells (hESC-MSC-Exos) on two types of DNA damage, namely, intra-/inter-strand crosslinks and DNA double-strand breaks induced by cisplatin (Pt) and bleomycin (BLM), respectively, in HeLa cells. The alkaline comet assay demonstrated that hESC-MSC-Exos effectively inhibited Pt- and BLM-induced DNA damage in a dose-dependent manner. When the concentration of hESC-MSC-Exos reaches 2.0 × 10⁶ and 4.0 × 10⁶ particles/mL in Pt- and BLM-treated groups, respectively, there was a significant decrease in tail DNA percentage (Pt: 20.80 ± 1.61 vs 9.40 ± 1.14, p < 0.01; BLM: 21.80 ± 1.31 vs 6.70 ± 0.60, p < 0.01), tail moment (Pt: 10.00 ± 1.21 vs 2.08 ± 0.51, p < 0.01; BLM: 12.00 ± 0.81 vs 2.00 ± 0.21, p < 0.01), and olive tail moment (Pt: 6.01 ± 0.55 vs 2.09 ± 0.25, p < 0.01; BLM: 6.03 ± 0.37 vs 1.53 ± 0.13, p < 0.01). Phospho-histone H2AX (γH2AX) immunofluorescence and western blotting showed an over 50 % decrease in γH2AX expression when the cells were pretreated with hESC-MSC-Exos. As reactive oxygen species (ROS) are important mediators of Pt- and BLM-induced DNA damage, dichloro-dihydro-fluorescein diacetate staining indicated that hESC-MSC-Exos inhibited the increase in intracellular ROS in drug-treated cells. In conclusion, our findings suggest that hESC-MSC-Exos can protect cells from the two types of DNA-damaging drugs and that reduced intracellular ROS is involved in this effect.

Cytosolic Release of Mitochondrial DNA and Associated cGAS Signaling Mediates Radiation-Induced Hematopoietic Injury of Mice

Mitochondrion is an important organelle of eukaryotic cells and a critical target of ionizing radiation (IR) outside the nucleus. The biological significance and mechanism of the non-target effect originating from mitochondria have received much attention in the field of radiation biology and protection. In this study, we investigated the effect, role, and radioprotective significance of cytosolic mitochondrial DNA (mtDNA) and its associated cGAS signaling on hematopoietic injury induced by IR in vitro culture cells and in vivo total body irradiated mice in this study. The results demonstrated that γ-ray exposure increases the release of mtDNA into the cytosol to activate cGAS signaling pathway, and the voltage-dependent anion channel (VDAC) may contribute to IR-induced mtDNA release. VDAC1 inhibitor DIDS and cGAS synthetase inhibitor can alleviate bone marrow injury and ameliorate hematopoietic suppression induced by IR via protecting hematopoietic stem cells and adjusting subtype distribution of bone marrow cells, such as attenuating the increase of the F4/80⁺ macrophage proportion in bone marrow cells. The present study provides a new mechanistic explanation for the radiation non-target effect and an alternative technical strategy for the prevention and treatment of hematopoietic acute radiation syndrome.

Molecular targets that sensitize cancer to radiation killing: From the bench to the bedside

Radiotherapy is a standard cytotoxic therapy against solid cancers. It uses ionizing radiation to kill tumor cells through damage to DNA, either directly or indirectly. Radioresistance is often associated with dysregulated DNA damage repair processes. Most radiosensitizers enhance radiation-mediated DNA damage and reduce the rate of DNA repair ultimately leading to accumulation of DNA damages, cell-cycle arrest, and cell death. Recently, agents targeting key signals in DNA damage response such as DNA repair pathways and cell-cycle have been developed. This new class of molecularly targeted radiosensitizing agents is being evaluated in preclinical and clinical studies to monitor their activity in potentiating radiation cytotoxicity of tumors and reducing normal tissue toxicity. The molecular pathways of DNA damage response are reviewed with a focus on the repair mechanisms, therapeutic targets under current clinical evaluation including ATM, ATR, CDK1, CDK4/6, CHK1, DNA-PKcs, PARP-1, Wee1, & MPS1/TTK and potential new targets (BUB1, and DNA LIG4) for radiation sensitization.

Lactobacillus rhamnosus GG ameliorates radiation-induced lung fibrosis via lncRNASNHG17/PTBP1/NICD axis modulation

Radiation-induced pulmonary fibrosis (RIPF) is a major side effect experienced for patients with thoracic cancers after radiotherapy. RIPF is poor prognosis and limited therapeutic options available in clinic. Lactobacillus rhamnosus GG (LGG) is advantaged and widely used for health promotion. However. Whether LGG is applicable for prevention of RIPF and relative underlying mechanism is poorly understood. Here, we reported a unique comprehensive analysis of the impact of LGG and its' derived lncRNA SNHG17 on radiation-induced epithelial-mesenchymal transition (EMT) in vitro and RIPF in vivo. As revealed by high-throughput sequencing, SNHG17 expression was decreased by LGG treatment in A549 cells post radiation and markedly attenuated the radiation-induced EMT progression (p < 0.01). SNHG17 overexpression correlated with poor overall survival in patients with lung cancer. Mechanistically, SNHG17 can stabilize PTBP1 expression through binding to its 3'UTR, whereas the activated PTBP1 can bind with the NICD part of Notch1 to upregulate Notch1 expression and aggravated EMT and lung fibrosis post radiation. However, SNHG17 knockdown inhibited PTBP1 and Notch1 expression and produced the opposite results. Notably, A549 cells treated with LGG also promoted cell apoptosis and increased cell G2/M arrest post radiation. Mice of RIPF treated with LGG decreased SNHG17 expression and attenuated lung fibrosis. Altogether, these data reveal that modulation of radiation-induced EMT and lung fibrosis by treatment with LGG associates with a decrease in SNHG17 expression and the inhibition of SNHG17/PTBP1/Nothch1 axis. Collectively, our results indicate that LGG exerts protective effects in RIPF and SNHG17 holds a potential marker of RIPF recovery in patients with thoracic cancers.

A Review of Radiation-Induced Alterations of Multi-Omic Profiles, Radiation Injury Biomarkers, and Countermeasures

Increasing utilization of nuclear power enhances the risks associated with industrial accidents, occupational hazards, and the threat of nuclear terrorism. Exposure to ionizing radiation interferes with genomic stability and gene expression resulting in the disruption of normal metabolic processes in cells and organs by inducing complex biological responses. Exposure to high-dose radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, cerebrovascular, and many other organ-specific injuries. Altered genomic variations, gene expression, metabolite concentrations, and microbiota profiles in blood plasma or tissue samples reflect the whole-body radiation injuries. Hence, multi-omic profiles obtained from high-resolution omics platforms offer a holistic approach for identifying reliable biomarkers to predict the radiation injury of organs and tissues resulting from radiation exposures. In this review, we performed a literature search to systematically catalog the radiation-induced alterations from multi-omic studies and radiation countermeasures. We covered radiation-induced changes in the genomic, transcriptomic, proteomic, metabolomic, lipidomic, and microbiome profiles. Furthermore, we have covered promising multi-omic biomarkers, FDA-approved countermeasure drugs, and other radiation countermeasures that include radioprotectors and radiomitigators. This review presents an overview of radiation-induced alterations of multi-omics profiles and biomarkers, and associated radiation countermeasures.

Effect of chronic intermittent ethanol vapor exposure on RNA content of brain-derived extracellular vesicles

Extracellular vesicles (EVs) are important players in normal biological function and disease pathogenesis. Of the many biomolecules packaged into EVs, coding and noncoding RNA transcripts are of particular interest for their ability to significantly alter cellular and molecular processes. Here we investigate how chronic ethanol exposure impacts EV RNA cargo and the functional outcomes of these changes. Following chronic intermittent ethanol (CIE) vapor exposure, EVs were isolated from male and female C57BL/6J mouse brain. Total RNA from EVs was analyzed by lncRNA/mRNA microarray to survey changes in RNA cargo following vapor exposure. Differential expression analysis of microarray data revealed a number of lncRNA and mRNA types differentially expressed in CIE compared to control EVs. Weighted gene co-expression network analysis identified multiple male and female specific modules related to neuroinflammation, cell death, demyelination, and synapse organization. To functionally test these changes, whole-cell voltage-clamp recordings were used to assess synaptic transmission. Incubation of nucleus accumbens brain slices with EVs led to a reduction in spontaneous excitatory postsynaptic current amplitude, although no changes in synaptic transmission were observed between control and CIE EV administration. These results indicate that CIE vapor exposure significantly changes the RNA cargo of brain-derived EVs, which have the ability to impact neuronal function.

Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation

The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.

The emerging role of exosomes in radiotherapy

Presently, more than half of cancer patients receive radiotherapy to cure localized cancer, palliate symptoms, or control the progression of cancer. However, radioresistance and radiation-induced bystander effects (RIBEs) are still challenging problems in cancer treatment. Exosomes, as a kind of extracellular vesicle, have a significant function in mediating and regulating intercellular signaling pathways. An increasing number of studies have shown that radiotherapy can increase exosome secretion and alter exosome cargo. Furthermore, radiation-induced exosomes are involved in the mechanism of radioresistance and RIBEs. Therefore, exosomes hold great promise for clinical application in radiotherapy. In this review, we not only focus on the influence of radiation on exosome biogenesis, secretion and cargoes but also on the mechanism of radiation-induced exosomes in radioresistance and RIBEs, which may expand our insight into the cooperative function of exosomes in radiotherapy.

Exosomes and mimics as novel delivery platform for cancer therapy

Exosomes are nano-sized biological extracellular vesicles transmitting information between cells and constituting a new intercellular communication mode. Exosomes have many advantages as an ideal drug delivery nanocarrier, including good biocompatibility, permeability, low toxicity, and low immunogenicity. Recently, exosomes have been used to deliver chemotherapeutic agents, natural drugs, nucleic acid drugs, and other antitumor drugs to treat many types of tumors. Due to the limited production of exosomes, synthetic exosome-mimics have been developed as an ideal platform for drug delivery. This review summarizes recent advances in the application of exosomes and exosome-mimics delivering therapeutic drugs in treating cancers.

The Neuroprotective Effects of Exosomes Derived from TSG101-Overexpressing Human Neural Stem Cells in a Stroke Model

Although tissue-type plasminogen activator was approved by the FDA for early reperfusion of occluded vessels, there is a need for an effective neuroprotective drug for stroke patients. In this study, we established tumor susceptibility gene (TSG)101-overexpressing human neural stem cells (F3.TSG) and investigated whether they showed enhanced secretion of exosomes and whether treatment with exosomes during reperfusion alleviated ischemia-reperfusion-mediated brain damage. F3.TSG cells secreted higher amounts of exosomes than the parental F3 cells. In N2A cells subjected to oxygen–glucose deprivation (OGD), treatment with exosomes or coculture with F3.TSG cells significantly attenuated lactate dehydrogenase release, the mRNA expression of proinflammatory factors, and the protein expression of DNA-damage-related proteins. In a middle cerebral artery occlusion (MCAO) rat model, treatment with exosomes, F3 cells, or F3.TSG cells after 2 h of occlusion followed by reperfusion reduced the infarction volume and suppressed inflammatory cytokines, DNA-damage-related proteins, and glial fibrillary acidic protein, and upregulated several neurotrophic factors. Thus, TSG101-overexpressing neural stem cells showed enhanced exosome secretion; exosome treatment protected against MCAO-induced brain damage via anti-inflammatory activities, DNA damage pathway inhibition, and growth/trophic factor induction. Therefore, exosomes and F3.TSG cells can affect neuroprotection and functional recovery in acute stroke patients.

Breast cancer extracellular vesicles-derived miR-1290 activates astrocytes in the brain metastatic microenvironment via the FOXA2→CNTF axis to promote progression of brain metastases

Mechanisms underlying breast cancer brain metastasis (BCBM) are still unclear. In this study, we observed that extracellular vesicles (EVs) secreted from breast cancer cells with increased expression of tGLI1, a BCBM-promoting transcription factor, strongly activated astrocytes. EV-derived microRNA/miRNA microarray revealed tGLI1-positive breast cancer cells highly secreted miR-1290 and miR-1246 encapsulated in EVs. Genetic knockin/knockout studies established a direct link between tGLI1 and both miRNAs. Datamining and analysis of patient samples revealed that BCBM patients had more circulating EV-miRs-1290/1246 than those without metastasis. Ectopic expression of miR-1290 or miR-1246 strongly activated astrocytes whereas their inhibitors abrogated the effect. Conditioned media from miR-1290- or miR-1246-overexpressing astrocytes promoted mammospheres. Furthermore, miRs-1290/1246 suppressed expression of FOXA2 transcription repressor, leading to CNTF cytokine secretion and subsequent activation of astrocytes. Finally, we conducted a mouse study to demonstrate that astrocytes overexpressing miR-1290, but not miR-1246, enhanced intracranial colonization and growth of breast cancer cells. Collectively, our findings demonstrate, for the first time, that breast cancer EV-derived miR-1290 and miR-1246 activate astrocytes in the brain metastatic microenvironment and that EV-derived miR-1290 promotes progression of brain metastases through the novel EV-miR-1290→FOXA2→CNTF signaling axis.

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 intercellular communications mediating radiation-induced bystander effects and their relevance to environmental, occupational, and therapeutic exposures

PURPOSE

The assumption that traversal of the cell nucleus by ionizing radiation is a prerequisite to induce genetic damage, or other important biological responses, has been challenged by studies showing that oxidative alterations extend beyond the irradiated cells and occur also in neighboring bystander cells. Cells and tissues outside the radiation field experience significant biochemical and phenotypic changes that are often similar to those observed in the irradiated cells and tissues. With relevance to the assessment of long-term health risks of occupational, environmental and clinical exposures, measurable genetic, epigenetic, and metabolic changes have been also detected in the progeny of bystander cells. How the oxidative damage spreads from the irradiated cells to their neighboring bystander cells has been under intense investigation. Following a brief summary of the trends in radiobiology leading to this paradigm shift in the field, we review key findings of bystander effects induced by low and high doses of various types of radiation that differ in their biophysical characteristics. While notable mechanistic insights continue to emerge, here the focus is on the many means of intercellular communication that mediate these effects, namely junctional channels, secreted molecules and extracellular vesicles, and immune pathways.

CONCLUSIONS

The insights gained by studying radiation bystander effects are leading to a basic understanding of the intercellular communications that occur under mild and severe oxidative stress in both normal and cancerous tissues. Understanding the mechanisms underlying these communications will likely contribute to reducing the uncertainty of predicting adverse health effects following exposure to low dose/low fluence ionizing radiation, guide novel interventions that mitigate adverse out-of-field effects, and contribute to better outcomes of radiotherapeutic treatments of cancer. In this review, we highlight novel routes of intercellular communication for investigation, and raise the rationale for reconsidering classification of bystander responses, abscopal effects, and expression of genomic instability as non-targeted effects of radiation.

The Role of MicroRNA in DNA Damage Response

DNA is essential for the development and function of organisms. A number of factors affect DNA integrity and cause DNA damages, such as ultraviolet light, ionizing radiation and hydrogen peroxide. DNA damages activate a series of intracellular reactions, called DNA damage response, which play a crucial role in the pathogenesis of cancers and other diseases. MiRNA is a type of evolutionarily conserved non-coding RNA and affects the expression of target genes by post-transcriptional regulation. Increasing evidences suggested that the expression of some miRNAs was changed in tumor cases. MiRNAs may participate in DNA damage response and affect genomic stability via influencing the processes of cell cycle, DNA damage repair and apoptosis, thus ultimately impact on tumorigenesis. Therefore, the role of miRNA in DNA damage response is reviewed, to provide a theoretical basis for the mechanism of miRNAs' effects on DNA damage response and for the research of new therapies for diseases.

Potential role of PRKCSH in lung cancer: bioinformatics analysis and a case study of Nano ZnO

PRKCSH, also known as glucosidase II beta, functions as a contributor to lung tumorigenesis by regulating the cell cycle in a p53-dependent manner under severe environmental stress. However, the prognostic value and molecular mechanisms by which the level of PRKCSH is significantly increased in cancer cells are not clearly understood. Here, we first generated a biological profile of PRKCSH expression changes in cancers by analysing bioinformatic data from cancer databases. We found that higher PRKCSH expression was correlated with a poorer prognosis and greater infiltration of most immune cell types in patients with lung cancer. In particular, PRKCSH expression showed significant negative correlations with the level of STAT6 (r = -0.31, p < 0.001) in lung cancer tissues. We further found that PRKCSH deficiency promoted G2/M arrest in response to zinc oxide nanoparticle (Nano ZnO) treatment in A549 cells. With regard to the mechanism, PRKCSH deficiency may induce STAT6 translocation to the nucleus to activate p53 expression through binding to the p53 promoter region from -365 bp to +126 bp. Eventually, activated p53 contributed to Nano-ZnO-induced G2/M arrest in lung cancer cells. Taken together, our data provide new insights into immunotherapy target choices and the prognostic value of PRKCSH. Since the G2/M cell cycle checkpoint is crucial for lung cancer prognosis, targeting PRKCSH expression to suppress the activation of the STAT6/p53 pathway is a potential therapeutic strategy for managing lung cancer.

Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair

The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.

Home and Away: The Role of Non-Coding RNA in Intracellular and Intercellular DNA Damage Response

Non-coding RNA (ncRNA) has recently emerged as a vital component of the DNA damage response (DDR), which was previously believed to be solely regulated by proteins. Many species of ncRNA can directly or indirectly influence DDR and enhance DNA repair, particularly in response to double-strand DNA breaks, which may hold therapeutic potential in the context of cancer. These include long non-coding RNA (lncRNA), microRNA, damage-induced lncRNA, DNA damage response small RNA, and DNA:RNA hybrid structures, which can be categorised as cis or trans based on the location of their synthesis relative to DNA damage sites. Mechanisms of RNA-dependent DDR include the recruitment or scaffolding of repair factors at DNA break sites, the regulation of repair factor expression, and the stabilisation of repair intermediates. DDR can also be communicated intercellularly via exosomes, leading to bystander responses in healthy neighbour cells to generate a population-wide response to damage. Many microRNA species have been directly implicated in the propagation of bystander DNA damage, autophagy, and radioresistance, which may prove significant for enhancing cancer treatment via radiotherapy. Here, we review recent developments centred around ncRNA and their contributions to intracellular and intercellular DDR mechanisms.

Targeted and Non-Targeted Mechanisms for Killing Hypoxic Tumour Cells-Are There New Avenues for Treatment?

PURPOSE

A major issue in radiotherapy is the relative resistance of hypoxic cells to radiation. Historic approaches to this problem include the use of oxygen mimetic compounds to sensitize tumour cells, which were unsuccessful. This review looks at modern approaches aimed at increasing the efficacy of targeting and radiosensitizing hypoxic tumour microenvironments relative to normal tissues and asks the question of whether non-targeted effects in radiobiology may provide a new "target". Novel techniques involve the integration of recent technological advancements such as nanotechnology, cell manipulation, and medical imaging. Particularly, the major areas of research discussed in this review include tumour hypoxia imaging through PET imaging to guide carbogen breathing, gold nanoparticles, macrophage-mediated drug delivery systems used for hypoxia-activate prodrugs, and autophagy inhibitors. Furthermore, this review outlines several features of these methods, including the mechanisms of action to induce radiosensitization, the increased accuracy in targeting hypoxic tumour microenvironments relative to normal tissue, preclinical/clinical trials, and future considerations.

CONCLUSIONS

This review suggests that the four novel tumour hypoxia therapeutics demonstrate compelling evidence that these techniques can serve as powerful tools to increase targeting efficacy and radiosensitizing hypoxic tumour microenvironments relative to normal tissue. Each technique uses a different way to manipulate the therapeutic ratio, which we have labelled "oxygenate, target, use, and digest". In addition, by focusing on emerging non-targeted and out-of-field effects, new umbrella targets are identified, which instead of sensitizing hypoxic cells, seek to reduce the radiosensitivity of normal tissues.

Different co-culture models reveal the pivotal role of TBBPA-promoted M2 macrophage polarization in the deterioration of endometrial cancer

Tetrabromobisphenol A (TBBPA), an emerging organic pollutant widely detected in human samples, has a positive correlation with the development of endometrial cancer (EC), but its underlying mechanisms have not yet been fully elucidated. Tumor-associated macrophages (TAM), one of the most vital components in tumor microenvironment (TME), play regulatory roles in the progression of EC. Consequently, this study mainly focuses on the macrophage polarization in TME to unveil the influence of TBBPA on the progression of EC and involved mechanisms. Primarily, low doses of TBBPA treatment up-regulated M2-like phenotype biomarkers in macrophage. The data from in vitro co-culture models suggested TBBPA-driven M2 macrophage polarization was responsible for the EC deterioration. Results from in vivo study further confirmed the malignant proliferation of EC promoted by TBBPA. Mechanistically, TBBPA-mediated miR-19a bound to the 3'-UTR regions of SOCS1, resulting in down-regulation of SOCS1 followed by the phosphorylation of JAK and STAT6. The present study not only revealed for the first time the molecular mechanism of TBBPA-induced EC's deterioration based on macrophage polarization, but also established co-culture models, thus providing a further evaluation method for the exploration of environmental pollutants-induced tumor effects from the role of TME.

It takes a village: microbiota, parainflammation, paligenosis and bystander effects in colorectal cancer initiation

Sporadic colorectal cancer (CRC) is a leading cause of worldwide cancer mortality. It arises from a complex milieu of host and environmental factors, including genetic and epigenetic changes in colon epithelial cells that undergo mutation, selection, clonal expansion, and transformation. The gut microbiota has recently gained increasing recognition as an additional important factor contributing to CRC. Several gut bacteria are known to initiate CRC in animal models and have been associated with human CRC. In this Review, we discuss the factors that contribute to CRC and the role of the gut microbiota, focusing on a recently described mechanism for cancer initiation, the so-called microbiota-induced bystander effect (MIBE). In this cancer mechanism, microbiota-driven parainflammation is believed to act as a source of endogenous mutation, epigenetic change and induced pluripotency, leading to the cancerous transformation of colon epithelial cells. This theory links the gut microbiota to key risk factors and common histologic features of sporadic CRC. MIBE is analogous to the well-characterized radiation-induced bystander effect. Both phenomena drive DNA damage, chromosomal instability, stress response signaling, altered gene expression, epigenetic modification and cellular proliferation in bystander cells. Myeloid-derived cells are important effectors in both phenomena. A better understanding of the interactions between the gut microbiota and mucosal immune effector cells that generate bystander effects can potentially identify triggers for parainflammation, and gain new insights into CRC prevention.

An indispensable tool: Exosomes play a role in therapy for radiation damage

Radiotherapy is one of the three main treatments for tumors. Almost 70% of tumor patients undergo radiotherapy at different periods. Although radiotherapy can enhance the local control rate of tumors and patients' quality of life, normal tissues often show radiation damage following radiotherapy. In recent years, several studies have shown that exosomes could be biomarkers for diseases and be involved in the treatment of radiation damage. Exosomes are nanoscale vesicles containing complex miRNAs and proteins. They can regulate the inflammatory response, enhance the regeneration effect of damaged tissue, and promote the repair of damaged tissues and cells, extending their survival time. In addition, their functions are achieved by paracrine signaling. In this review, we discuss the potential of exosomes as biomarkers and introduce the impact of exosomes on radiation damage in different organs and the hematopoietic system in detail.

Small Extracellular Vesicles: A Novel Avenue for Cancer Management

Extracellular vesicles are small membrane particles derived from various cell types. EVs are broadly classified as ectosomes or small extracellular vesicles, depending on their biogenesis and cargoes. Numerous studies have shown that EVs regulate multiple physiological and pathophysiological processes. The roles of small extracellular vesicles in cancer growth and metastasis remain to be fully elucidated. As endogenous products, small extracellular vesicles are an ideal drug delivery platform for anticancer agents. However, several aspects of small extracellular vesicle biology remain unclear, hindering the clinical implementation of small extracellular vesicles as biomarkers or anticancer agents. In this review, we summarize the utility of cancer-related small extracellular vesicles as biomarkers to detect early-stage cancers and predict treatment outcomes. We also review findings from preclinical and clinical studies of small extracellular vesicle-based cancer therapies and summarize interventional clinical trials registered in the United States Food and Drug Administration and the Chinese Clinical Trials Registry. Finally, we discuss the main challenges limiting the clinical implementation of small extracellular vesicles and recommend possible approaches to address these challenges.

Exosome-mediated cellular crosstalk within the tumor microenvironment upon irradiation

Radiotherapy is one of the most effective treatment methods for various solid tumors. Bidirectional signal transduction between cancer cells and stromal cells within the irradiated microenvironment is important in cancer development and treatment responsiveness. Exosomes, initially considered as “garbage bins” for unwanted from cells, are now understood to perform a variety of functions in interactions within the tumor microenvironment. Exosome-mediated regulation processes are rebuilt under the irradiation stimuli, because the exosome production, uptake, and contents are markedly modified by irradiation. In turn, irradiation-modified exosomes may modulate the cell response to irradiation through feedback regulation. Here, we review current knowledge and discuss the roles of exosome-mediated interactions between cells under radiotherapy conditions.

Radiation Can Regulate the Expression of miRNAs Associated with Osteogenesis and Oxidation in Exosomes from Peripheral Blood Plasma

Objectives

Radiotherapy is a common therapy in head and neck tumors, which may cause a side effect radiation bone injury (RBI). Furthermore, it has been investigated that microRNA (miRNA) expression levels were altered after radiotherapy. Exosomes play a role in bone formation as miRNA containers, while radiation affects exosomes composition, secretion, and function. So, our objective is to explore changes in miRNA levels during bone formation after radiotherapy and identify the differentially expressed miRNAs (DE-miRs) in plasma exosomes during the process of osteogenesis related to irradiation.

Materials and Methods

In this study, we analyzed nine samples from three rabbits exposed twice to radiation (15 Gy each) and detected DE-miRs from irradiated plasma exosomes during the process of osteogenesis by RNA sequencing. Further, we identified DE-miRs with significant differences and predicted their target genes via the bioinformatics analysis tools Targetscan v7.2 and miRPathDB v2.0. Finally, we identified radiation-responsive miRNAs and predicted their target genes during osteogenesis.

Results

Taken together, we have identified some DE-miRs in irradiated plasma exosomes, which were involved in several vital signaling pathways related to bone physiology, such as the Wnt pathway, MAPK cascade, and calcium modulating pathway.

Conclusions

We have found that plasma exosomes are one of the ways by which radiation can affect bone metabolism and regeneration. However, the specific mechanisms of how these plasma exosomal miRNAs mediate the osteogenesis pathways must be further investigated. Clinical Relevance. Radiotherapy may cause radiation bone injury, and miRNA expression levels in rabbit plasma exosomes are altered after radiotherapy. High-throughput RNA sequencing can identify the differentially expressed miRNAs in irradiated plasma exosomes during the process of osteogenesis. These findings make sense to develop novel therapeutic strategies for treating radiation-induced bone injury disorders.

Transcriptomic and metabolomic profiling reveal the p53-dependent benzeneacetic acid attenuation of silica-induced epithelial-mesenchymal transition in human bronchial epithelial cells

BACKGROUND

Silica exposure underlies the development of silicosis, one of the most serious occupational hazards worldwide. We aimed to explore the interaction of the silica-induced epithelial-mesenchymal transition (EMT)-related transcripts with the cellular metabolism regulated by p53.

METHODS

We knocked out p53 using CRISPR/Cas9 in the human bronchial epithelial (HBE) cell line. The transcriptomic and metabolomic analyses and integrative omics were conducted using microarrays, GC-MS, and MetaboAnalyst, respectively.

RESULTS

Fifty-two mRNAs showed significantly altered expression in the HBE p53-KO cells post-silica exposure. A total of 42 metabolites were putatively involved in p53-dependent silica-mediated HBE cell dysfunction. Through integrated data analysis, we obtained five significant p53-dependent metabolic pathways including phenylalanine, glyoxylate, dicarboxylate, and linoleic acid metabolism, and the citrate cycle. Through metabolite screening, we further identified that benzeneacetic acid, a key regulation metabolite in the phenylalanine metabolic pathway, attenuated the silica-induced EMT in HBE cells in a p53-dependent manner. Interestingly, despite the extensive p53-related published literature, the clinical translation of these studies remains unsubstantial.

CONCLUSIONS

Our study offers new insights into the molecular mechanisms by which epithelial cells respond to silica exposure and provide fresh perspective and direction for future clinical biomarker research and potential clinically sustainable and translatable role of p53.

Landscape of extracellular vesicles in the tumour microenvironment: Interactions with stromal cells and with non-cell components, and impacts on metabolic reprogramming, horizontal transfer of neoplastic traits, and the emergence of therapeutic resistance

Extracellular vesicles (EVs) are increasingly recognised as a pivotal player in cell-cell communication, an attribute of EVs that derives from their ability to transport bioactive cargoes between cells, resulting in complex intercellular signalling mediated by EVs, which occurs under both physiological and pathological conditions. In the context of cancer, recent studies have demonstrated the versatile and crucial roles of EVs in the tumour microenvironment (TME). Here, we revisit EV biology, and focus on EV-mediated interactions between cancer cells and stromal cells, including fibroblasts, immune cells, endothelial cells and neurons. In addition, we focus on recent reports indicating interactions between EVs and non-cell constituents within the TME, including the extracellular matrix. We also review and summarise the intricate cancer-associated network modulated by EVs, which promotes metabolic reprogramming, horizontal transfer of neoplastic traits, and therapeutic resistance in the TME. We aim to provide a comprehensive and updated landscape of EVs in the TME, focusing on oncogenesis, cancer progression and therapeutic resistance, together with our future perspectives on the field.

Role of epigenetic mechanisms in propagating off-targeted effects following radiation based therapies - A review

Despite being an important diagnostic and treatment modality, ionizing radiation (IR) is also known to cause genotoxicity and multiple side effects leading to secondary carcinogenesis. While modern cancer radiation therapy has improved patient recovery and enhanced survival rates, the risk of radiation-related adverse effects has become a growing challenge. It is now well-accepted that IR-induced side effects are not exclusively restricted to exposed cells but also spread to distant 'bystander' cells and even to the unexposed progeny of the irradiated cells. These 'off-targeted' effects involve a plethora of molecular events depending on the type of radiation and tumor tissue background. While the mechanisms by which off-targeted effects arise remain obscure, emerging evidence based on the non-mendelian inheritance of various manifestations of them as well as their persistence for longer periods supports a contribution of epigenetic factors. This review focuses on the major epigenetic phenomena including DNA methylation, histone modifications, and small RNA mediated silencing and their versatile role in the manifestation of IR induced off-targeted effects. As short- and long-range communication vehicles respectively, the role of gap junctions and exosomes in spreading these epigenetic-alteration driven off-targeted effects is also discussed. Furthermore, this review emphasizes the possible therapeutic potentials of these epigenetic mechanisms and how beneficial outcomes could potentially be achieved by targeting various signaling molecules involved in these mechanisms.

Altered microRNA Profiles of Extracellular Vesicles Secreted by Endometrial Cells from Women with Recurrent Implantation Failure

Recurrent implantation failure (RIF) is characterized by repeated embryo transfers without pregnancy. To date, the etiology of RIF remains poorly understood. Accumulating evidence indicates a beneficial role of endometrial extracellular vesicles (EVs) during the implantation by delivering signaling molecules to embryos, especially miRNAs. However, whether EVs secreted by RIF patients' endometria have a similar miRNA expression profile of endometrial EVs of fertile women has not been investigated. Therefore, in this study, we compared the miRNA expression profiles between the endometrial EVs of RIF patients (RIF-EVs) and fertile women (FER-EVs). Endometrial tissues from fifteen RIF patients and nine fertile women were collected and digested to cells for culture. Endometrial cells were modulated by estrogen and progesterone to mimic the secretory phase, and the conditioned medium was collected for EV isolation. EVs were determined by western blotting, nanoparticle tracking analysis, and transmission electronic microscopy (TEM). Three pairs of EV samples from two groups were used for miRNA sequencing, and twelve RIF-EV samples and six FER-EV samples were used for validation using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results showed that a total of 11 miRNAs were differently expressed in the RIF-EVs. Besides, four of the differently expressed miRNAs were validated using qRT-PCR. Target genes of the differently expressed miRNAs were predicted, and the functional analysis was performed. Besides, we proved that the most significantly different miRNA, 6131, inhibited the growth and invasion of HTR8/SVneo cells. Our study suggested that the altered miRNAs in the RIF-EVs might be involved in the pathogenesis of RIF.

The p53/RMRP/miR122 signaling loop promotes epithelial-mesenchymal transition during the development of silica-induced lung fibrosis by activating the notch pathway

BACKGROUND

Understanding the roles of long noncoding RNAs (lncRNAs) in EMT would help with establishing novel avenues for further uncovering the mechanisms of lung fibrosis and identifying preventative and therapeutic targets. This study aimed to identify silica-induced specific lncRNAs and investigate the feedback loop regulation among their upstream and downstream genes.

METHODS AND MATERIALS

A microarray assay, quantitative real-time polymerase chain reaction and Western blot analysis dual-luciferase reporter gene activity and chromatin immunoprecipitation assays were used. Moreover, a silica-induced lung fibrosis mouse model was used to verify the roles of the lncRNAs.

RESULTS

Following silica exposure, both RNA component of mitochondrial RNA processing endoribonuclease (RMRP) and p53 were significantly upregulated during the EMT. The upregulation of p53 upon silica exposure activated RMRP expression, which promoted the EMT. When RMRP is overexpressed, additional RMRP acts as a sponge to bind to miR122, thus decreasing miR122 levels. Using microarrays, miR122 was identified as a potential upstream regulator of p53. This relationship was also verified using the dual-luciferase reporter gene. Hence, decreased miR122 levels result in an increase in p53 activity. More importantly, RMRP promotes the transcription of Notch 1, which, in turn, results in Notch pathway activation. We show that the p53/RMRP/miR122 pathway creates a positive feedback loop that promotes EMT progress by activating the Notch signaling pathway.

CONCLUSION

Our data indicated that p53/RMRP/miR122 feedback loop might contribute to the EMT development by activating Notch pathway, which provides new sight into understanding of the complex network regulating silica-induced lung fibrosis.

Exosomal MiR-769-5p Exacerbates Ultraviolet-Induced Bystander Effect by Targeting TGFBR1

Exosomal microRNAs have been investigated in bystander effect, but it is unclear whether microRNA works in ultraviolet radiation-induced bystander effects (UV-RIBEs) and what the underlying mechanism could be. Exosomes from ultraviolet (UV)-irradiated human skin fibroblasts (HSFs) were isolated and transferred to normal HSFs, followed by the detection of proliferation rate, oxidative damage level, and apoptosis rate. Exosomal miRNAs were evaluated and screened with miRNA sequencing and quantitative reverse transcriptase-polymerase chain reaction method. MiRNA shuttle and bystander photodamage reactions were observed after transfection of miR-769-5p. MiR-769-5p targeting gene transforming growth factor-β1 (TGFBR1), and TGFBR1 mRNA 3'-untranslated region (UTR) was assessed and identified by Western blotting and dual-luciferase reporter assay. Bystander effects were induced after being treated with isolated exosomes from UV-irradiated HSFs. Exosomal miR-769-5p expression was significantly upregulated. Human skin fibroblasts showed lower proliferation, increasing oxidative damage, and faster occurrence of apoptosis after transfection. Exosome-mediated transfer of miR-769-5p was observed. Upregulation of miR-769-5p induced bystander effects, whereas downregulation of miR-769-5p can suppress UV-RIBEs. In addition, miR-769-5p was found to downregulate TGFBR1 gene expression by directly targeting its 3'-UTR. Our results demonstrate that exosome-mediated miR-769-5p transfer could function as an intercellular messenger and exacerbate UV-RIBEs. MiR-769-5p inhibits the expression of TGFBR1 by targeting TGFBR1 mRNA 3'-UTR.

A Biomarker Panel of Radiation-Upregulated miRNA as Signature for Ionizing Radiation Exposure

Ionizing radiation causes serious injury to the human body and has long-time impacts on health. It is important to find optimal biomarkers for the early quick screening of exposed individuals. A series of miRNAs signatures have been developed as the new biomarkers for diagnosis, survival, and prognostic prediction of cancers. Here, we have identified the ionizing radiation-inducible miRNAs profile through microarray analysis. The biological functions were predicted for the top six upregulated miRNAs by 4 Gy γ-rays: miR-1246, miR-1307-3p, miR-3197, miR-4267, miR-5096 and miR-7641. The miRNA-gene network and target gene-pathway network analyses revealed that DNAH3 is the target gene associated with all the six miRNAs. GOLGB1 is related to 4 miRNAs and other 26 genes targeted by 3 miRNAs. The upregulation of fifteen miRNAs were further verified at 4 h and 24 h after 0 to 10 Gy irradiation in the human lymphoblastoid AHH-1 cells, and some demonstrated a dose-dependent increased. Six miRNAs, including miR-145, miR-663, miR-1273g-3p, miR-6090, miR-6727-5p and miR-7641, were validated to be dose-dependently upregulated at 4 h or 24 h post-irradiation in both AHH-1 and human peripheral blood lymphocytes irradiated ex vivo. This six-miRNA signature displays the superiority as a radiation biomarker for the translational application of screening and assessment of radiation exposed individuals.

Radiation-Induced Bystander Effect can be Transmitted Through Exosomes Using miRNAs as Effector Molecules

The radiation-induced bystander effect (RIBE) is a destructive reaction in nonirradiated cells and is one primary factor in determining the efficacy and success of radiation therapy in the field of cancer treatment. Previously reported studies have shown that the RIBE can be mediated by exosomes that carry miRNA components within. Exosomes, which are one type of cell-derived vesicle, exist in different biological conditions and serve as an important additional pathway for signal exchange between cells. In addition, exosome-derived miRNAs are confirmed to play an important role in RIBE, activating the bystander effect and genomic instability after radiotherapy. After investigating the field of RIBE, it is important to understand the mechanisms and consequences of biological effects as well as the role of exosomes and exosomal miRNAs therein, from different sources and under different circumstances, respectively. More discoveries could help to establish early interventions against RIBE while improving the efficacy of radiotherapy. Meanwhile, measures that would alleviate or even inhibit RIBE to some extent may exist in the near future.

Microarray analysis of aberrant microRNA expression patterns in spinal cord gliomas of different grades

MicroRNAs (miRNAs) are involved in the development of several types of tumor; however, their role in spinal gliomas remains unknown. The present study aimed to identify potentially novel spinal cord gliomas (SCG)-associated miRNAs and to characterize their roles in the development and progression of SCG. miRNA expression levels in low-grade SCG (classed as stage I–II SCG based on the World Health Organization grading system), high-grade SCG (classed as stage IV SCG based on the World Health Organization grading system) and 5 control cases were measured using a miRNA expression microarray. Subsequently, blood samples from the spinal cord of patients with differing grades of SCG were screened for differentially expressed miRNAs (DEmiRNAs). Compared with the control group, 7 upregulated and 36 downregulated miRNAs were identified in the low-grade SCG group and a total of 70 upregulated and 20 downregulated miRNAs were identified in the high-grade SCG group (P≤0.05, fold change >2). Gene Ontology analysis revealed that the regulation of cellular metabolic processes, negative regulation of biological processes and axon guidance were primarily involved. Moreover, pathway analysis showed that the target genes of DEmiRNAs were enriched in tumor-related signaling pathways, such as the MAPK and Wnt signaling pathway. The results suggest that DEmiRNAs in peripheral blood may serve as novel target markers with high specificity and sensitivity for the diagnosis of SCG.

Exosomes and exosomal microRNA in non-targeted radiation bystander and abscopal effects in the central nervous system

Localized cranial radiotherapy is a dominant treatment for brain cancers. After being subjected to radiation, the central nervous system (CNS) exhibits targeted effects as well as non-targeted radiation bystander effects (RIBE) and abscopal effects (RIAE). Radiation-induced targeted effects in the CNS include autophagy and various changes in tumor cells due to radiation sensitivity, which can be regulated by microRNAs. Non-targeted radiation effects are mainly induced by gap junctional communication between cells, exosomes containing microRNAs can be transduced by intracellular endocytosis to regulate RIBE and RIAE. In this review, we discuss the involvement of microRNAs in radiation-induced targeted effects, as well as exosomes and/or exosomal microRNAs in non-targeted radiation effects in the CNS. As a target pathway, we also discuss the Akt pathway which is regulated by microRNAs, exosomes, and/or exosomal microRNAs in radiation-induced targeted effects and RIBE in CNS tumor cells. As the CNS-derived exosomes can cross the blood-brain-barrier (BBB) into the bloodstream and be isolated from peripheral blood, exosomes and exosomal microRNAs can emerge as promising minimally invasive biomarkers and therapeutic targets for radiation-induced targeted and non-targeted effects in the CNS.

Jack of all trades? The versatility of RNA in DNA double-strand break repair

The mechanisms by which RNA acts in the DNA damage response (DDR), specifically in the repair of DNA double-strand breaks (DSBs), are emerging as multifaceted and complex. Different RNA species, including but not limited to; microRNA (miRNA), long non-coding RNA (lncRNA), RNA:DNA hybrid structures, the recently identified damage-induced lncRNA (dilncRNA), damage-responsive transcripts (DARTs), and DNA damage-dependent small RNAs (DDRNAs), have been shown to play integral roles in the DSB response. The diverse properties of these RNAs, such as sequence, structure, and binding partners, enable them to fulfil a variety of functions in different cellular contexts. Additionally, RNA can be modified post-transcriptionally, a process which is regulated in response to cellular stressors such as DNA damage. Many of these mechanisms are not yet understood and the literature contradictory, reflecting the complexity and expansive nature of the roles of RNA in the DDR. However, it is clear that RNA is pivotal in ensuring the maintenance of genome integrity. In this review, we will discuss and summarise recent evidence which highlights the roles of these various RNAs in preserving genomic integrity, with a particular focus on the emerging role of RNA in the DSB repair response.

The nanomaterial-induced bystander effects reprogrammed macrophage immune function and metabolic profile

Bystander effects in biological systems are the responses shown by nontargeted neighboring cells, and critical to the bio-nano interface interactions. In addition to direct effects, bystander effects also determine the design, applications and safety of nanomaterials, although the related information of nanomaterial-induced bystander effects remain largely unknown. A coculture system of A549 and THP-1 was established to mimic the lung microenvironment to study the bystander effects of WS₂ nanosheets (representative transition-metal dichalcogenide nanosheets) on microenvironment macrophages during the inhalation exposure or the nanomaterial biomedical application in the lung. Lung cells exposed to WS₂ nanosheet resulted in an increase in reactive oxygen species and the depolarization of mitochondrial membrane potential in neighboring macrophages. Bystander exposure also induced macrophage polarization toward the anti-inflammatory M2 phenotype, which is adverse to disease therapy. Metabolomics showed that WS₂ nanosheets disturbed the energy metabolism and amino acid metabolism of macrophages, consistent with the metabolic characteristics of M2 macrophages. Nitric oxide-transforming growth factor-β1 played an important mediator in the bystander effects. Importantly, WS₂ nanosheet bystander exposure affected macrophage phagocytosis and migration and altered the macrophage immune response to endotoxin. This study improves the current understanding of bio-nano interactions and highlights the importance of neighboring cell responses, allowing us to use the maximum benefits of nanomaterials while limiting their adverse bystander effects.

BECN1 promotes radiation-induced G2/M arrest through regulation CDK1 activity: a potential role for autophagy in G2/M checkpoint

Authophagy and G2/M arrest are two important mechanistic responses of cells to ionizing radiation (IR), in particular the IR-induced fibrosis. However, what interplayer and how it links the autophagy and the G2/M arrest remains elusive. Here, we demonstrate that the autophagy-related protein BECN1 plays a critical role in ionizing radiation-induced G2/M arrest. The treatment of cells with autophagy inhibitor 3-methyladenine (3-MA) at 0-12 h but not 12 h postirradiation significantly sensitized them to IR, indicating a radio-protective role of autophagy in the early response of cells to radiation. 3-MA and BECN1 disruption inactivated the G2/M checkpoint following IR by abrogating the IR-induced phosphorylation of phosphatase CDC25C and its target CDK1, a key mediator of the G2/M transition in coordination with CCNB1. Irradiation increased the nuclear translocation of BECN1, and this process was inhibited by 3-MA. We confirmed that BECN1 interacts with CDC25C and CHK2, and which is mediated the amino acids 89-155 and 151-224 of BECN1, respectively. Importantly, BECN1 deficiency disrupted the interaction of CHK2 with CDC25C and the dissociation of CDC25C from CDK1 in response to irradiation, resulting in the dephosphorylation of CDK1 and overexpression of CDK1. In summary, IR induces the translocation of BECN1 to the nucleus, where it mediates the interaction between CDC25C and CHK2, resulting in the phosphorylation of CDC25C and its dissociation from CDK1. Consequently, the mitosis-promoting complex CDK1/CCNB1 is inactivated, resulting in the arrest of cells at the G2/M transition. Our findings demonstrated that BECN1 plays a role in promotion of radiation-induced G2/M arrest through regulation of CDK1 activity. Whether such functions of BECN1 in G2/M arrest is dependent or independent on its autophagy-related roles is necessary to further identify.