Ionizing Radiation Increases the Activity of Exosomal Secretory Pathway in MCF-7 Human Breast Cancer Cells: A Possible Way to Communicate Resistance against Radiotherapy

Mechanical properties of blood exosomes and lipoproteins after the rat whole blood irradiation with X-rays in vitro explored by atomic force microscopy

Blood is a two-component system with two levels of hierarchy: the macrosystem of blood formed elements and the dispersed system of blood nanoparticles. Biological nanoparticles are the key participants in communication between the irradiated and non-irradiated cells and inducers of the non-targeted effects of ionizing radiation. The work aimed at studying by atomic force microscopy the structural, mechanical, and electrical properties of exosomes and lipoproteins (LDL/VLDL) isolated from rat blood after its exposure to X-rays in vitro.

MATERIALS AND METHODS

The whole blood of Wistar rats fed with a high-fat diet was irradiated with X-rays (1 and 100 Gy) in vitro. The structural and mechanical properties (the elastic modulus and nonspecific adhesion force) of exosome and lipoprotein isolates from the blood by ultracentrifugation method were studied using Bruker Bioscope Resolve atomic force microscope in PF QNM mode, their electric properties (the zeta-potential) was measured by electrophoretic mobility.

RESULTS

Lipoproteins isolated from non-irradiated blood were softer (Me(LQ; UQ): 7.8(4.9;12.1) MPa) compared to blood nanoparticles of its exosome fraction (34.8(22.6;44.9) MPa) containing both exosomes and non-membrane nanoparticles. X-ray blood irradiation with a dose of 1 Gy significantly weakened the elastic properties of lipoproteins. Exposure of the blood to 100 Gy X-rays made lipoproteins stiffer and their nonspecific adhesive properties stronger. The radiation effects on the mechanical parameters of exosomes and non-membrane nanoparticles in exosome fractions differed. The significant radiation-induced change in electric properties of the studied nanoparticles was detected only for lipoproteins in the blood irradiated with 1 Gy X-rays. The low-dose radiation-induced changes in zeta-potential and increase in lipoprotein size with the appearance of a soft thick surface layer indicate the formation of the modified lipoproteins covered with a corona from macromolecules of irradiated blood.

CONCLUSION

Our data obtained using the nanomechanical mapping mode of AFM are the first evidence of the significant radiation-induced changes in the structural and mechanical properties of the dispersed system of blood nanoparticles after the X-ray irradiation of the blood.

Physical modulation of mesenchymal stem cell exosomes: A new perspective for regenerative medicine

Mesenchymal stem cell-derived exosomes (MSC-Exo) offer promising therapeutic potential for various refractory diseases, presenting a novel therapeutic strategy. However, their clinical application encounters several obstacles, including low natural secretion, uncontrolled biological functions and inherent heterogeneity. On the one hand, physical stimuli can mimic the microenvironment dynamics where MSC-Exo reside. These factors influence not only their secretion but also, significantly, their biological efficacy. Moreover, physical factors can also serve as techniques for engineering exosomes. Therefore, the realm of physical factors assumes a crucial role in modifying MSC-Exo, ultimately facilitating their clinical translation. This review focuses on the research progress in applying physical factors to MSC-Exo, encompassing ultrasound, electrical stimulation, light irradiation, intrinsic physical properties, ionizing radiation, magnetic field, mechanical forces and temperature. We also discuss the current status and potential of physical stimuli-affected MSC-Exo in clinical applications. Furthermore, we address the limitations of recent studies in this field. Based on this, this review provides novel insights to advance the refinement of MSC-Exo as a therapeutic approach in regenerative medicine.

Extracellular vesicles and the "six Rs" in radiotherapy

Over half of patients with cancer receive radiation therapy during the course of their disease. Decades of radiobiological research have identified 6 parameters affecting the biological response to radiation referred to as the 6 "Rs": Repair, Radiosensitivity, Repopulation, Redistribution, Reoxygenation, and Reactivation of the anti-tumour immune response. Extracellular Vesicles (EVs) are small membrane-bound particles whose multiple biological functions are increasingly documented. Here we discuss the evidence for a role of EVs in the orchestration of the response of cancer cells to radiotherapy. We highlight that EVs are involved in DNA repair mechanisms, modulation of cellular sensitivity to radiation, and facilitation of tumour repopulation. Moreover, EVs influence tumour reoxygenation dynamics, and play a pivotal role in fostering radioresistance. Last, we examine how EV-related strategies could be translated into novel strategies aimed at enhancing the efficacy of radiation therapy against cancer.

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.

Advancing cancer treatment: in vivo delivery of therapeutic small noncoding RNAs

In recent years, small non-coding RNAs (ncRNAs) have emerged as a new player in the realm of cancer therapeutics. Their unique capacity to directly modulate genetic networks and target oncogenes positions them as valuable complements to existing small-molecule drugs. Concurrently, the advancement of small ncRNA-based therapeutics has rekindled the pursuit of efficacious in vivo delivery strategies. In this review, we provide an overview of the most current clinical and preclinical studies in the field of small ncRNA-based cancer therapeutics. Furthermore, we shed light on the pivotal challenges hindering the successful translation of these promising therapies into clinical practice, with a specific focus on delivery methods, aiming to stimulate innovative approaches to address this foundational aspect of cancer treatment.

Irradiated Cell-derived Exosomes Enhance Cell Proliferation and Radioresistance via the MAPK/Erk Pathway

BACKGROUND/AIM

Radiation therapy is pivotal in cancer treatment; however, its efficacy is limited by challenges such as tumor recurrence. This study delves into the role of exosomes, which are molecular cargo-bearing vesicles, in influencing cell proliferation, radioresistance, and consequent post-irradiation tumor recurrence. Given the significance of exosomes from irradiated malignancies in diagnostics and therapy, it is vital to delineate their functional dynamics, especially in breast and cervical cancer cell lines, where the impact of irradiation on exosome behavior remains enigmatic.

MATERIALS AND METHODS

Using MDA-MB-231 and HeLa cell lines, exosomes were isolated from the culture supernatant via ultracentrifugation. The bicinchoninic acid assay was used to measure exosome quantities in irradiated and non-irradiated cells. Radiosensitivity was assessed using colony formation assays, while the role of the MAPK/Erk signaling pathway in recipient cell proliferation and radioresistance was probed using western blotting.

RESULTS

Irradiated cells, in both MDA-MB-231 and HeLa lines, produced significantly more exosomes than their non-irradiated counterparts. Co-culturing irradiated cells with exosomes led to increased cell survival post-irradiation and enhanced cell proliferation in both cell lines. Western blotting indicated elevated p-Erk expression in such cells, underscoring the influence of the MAPK/Erk pathway in radioresistance and proliferation.

CONCLUSION

The study establishes a potential nexus between exosome secretion and tumor resurgence following radiotherapy. The spotlight falls on the MAPK/ERK signaling conduit as a key influencer. This new knowledge provides an innovative strategy for counteracting cancer recurrence after radiotherapy, emphasizing the importance of understanding the multifaceted roles of exosomes in this context.

The Role of the Tumor Microenvironment in Triple-Positive Breast Cancer Progression and Therapeutic Resistance

Breast cancer (BRCA) is a highly heterogeneous systemic disease. It is ranked first globally in the incidence of new cancer cases and has emerged as the primary cause of cancer-related death among females. Among the distinct subtypes of BRCA, triple-positive breast cancer (TPBC) has been associated with increased metastasis and invasiveness, exhibiting greater resistance to endocrine therapy involving trastuzumab. It is now understood that invasion, metastasis, and treatment resistance associated with BRCA progression are not exclusively due to breast tumor cells but are from the intricate interplay between BRCA and its tumor microenvironment (TME). Accordingly, understanding the pathogenesis and evolution of the TPBC microenvironment demands a comprehensive approach. Moreover, addressing BRCA treatment necessitates a holistic consideration of the TME, bearing significant implications for identifying novel targets for anticancer interventions. This review expounds on the relationship between critical cellular components and factors in the TPBC microenvironment and the inception, advancement, and therapeutic resistance of breast cancer to provide perspectives on the latest research on TPBC.

Composition of Conditioned Media from Radioresistant and Chemoresistant Cancer Cells Reveals miRNA and Other Secretory Factors Implicated in the Development of Resistance

Resistance to chemo- or radiotherapy is the main obstacle to consistent treatment outcomes in oncology patients. A deeper understanding of the mechanisms driving the development of resistance is required. This review focuses on secretory factors derived from chemo- and radioresistant cancer cells, cancer-associated fibroblasts (CAFs), mesenchymal stem cells (MSCs), and cancer stem cells (CSCs) that mediate the development of resistance in unexposed cells. The first line of evidence considers the experiments with conditioned media (CM) from chemo- and radioresistant cells, CAFs, MSCs, and CSCs that elevate resistance upon the ionizing radiation or anti-cancer drug exposure of previously untreated cells. The composition of CM revealed factors such as circular RNAs; interleukins; plasminogen activator inhibitor; and oncosome-shuttled lncRNAs, mRNAs, and miRNAs that aid in cellular communication and transmit signals inducing the chemo- and radioresistance of sensitive cancer cells. Data, demonstrating that radioresistant cancer cells become resistant to anti-neoplastic drug exposure and vice versa, are also discussed. The mechanisms driving the development of cross-resistance between chemotherapy and radiotherapy are highlighted. The secretion of resistance-mediating factors to intercellular fluid and blood brings attention to its diagnostic potential. Highly stable serum miRNA candidates were proposed by several studies as prognostic markers of radioresistance; however, clinical studies are needed to validate their utility. The ability to predict a treatment response with the help of the miRNA resistance status database will help with the selection of an effective therapeutic strategy. The possibility of miRNA-based therapy is currently being investigated with ongoing clinical studies, and such approaches can be used to alleviate resistance in oncology patients.

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.

Strategies for targeted gene delivery using lipid nanoparticles and cell-derived nanovesicles

Gene therapy is a promising approach for the treatment of many diseases. However, the effective delivery of the cargo without degradation in vivo is one of the major hurdles. With the advent of lipid nanoparticles (LNPs) and cell-derived nanovesicles (CDNs), gene delivery holds a very promising future. The targeting of these nanosystems is a prerequisite for effective transfection with minimal side-effects. In this review, we highlight the emerging strategies utilized for the effective targeting of LNPs and CDNs, and we summarize the preparation methodologies for LNPs and CDNs. We have also highlighted the non-ligand targeting of LNPs toward certain organs based on their composition. It is highly expected that continuing the developments in the targeting approaches of LNPs and CDNs for the delivery system will further promote them in clinical translation.

Exosomal circRNAs in cancer: Implications for therapy resistance and biomarkers

Despite the advances in cancer treatment in recent years, the development of resistance to cancer therapy remains the biggest hurdle towards curative cancer treatments. Therefore, investigating the molecular mechanisms underlying cancer therapy resistance is of paramount clinical importance. Circular RNAs (circRNAs), novel members of the noncoding RNA family, are endogenous biomolecules in eukaryotes characterized by a covalently closed loop structure with multiple biological functions. Significantly, circRNAs are abundant and stable in exosomes and can be packaged, secreted and transferred to targeted tumour cells, thereby modulating diverse hallmarks of cancer behaviours, such as proliferation, migration, and immune escape. Notably, a great number of exosomal circRNAs are abnormally expressed during cancer treatment and can mediate cancer therapy resistance through complex mechanisms; therefore, targeting exosomal circRNAs is a promising therapeutic method to reverse therapy resistance. This review aimed to elucidate the mechanisms underlying exosomal circRNAs controlling the resistance of cancer to common therapies, such as chemotherapy, targeted therapy, immunotherapy and radiotherapy, and we also discussed the therapeutic potential of exosomal circRNAs as clinical biomarkers and novel targets in cancer clinical management. We also discussed the prospects and challenges of targeting exosomal circRNAs as a novel therapeutic strategy for reversing cancer therapy resistance.

The Acute Radiation Syndrome-Mitigator Romiplostim and Secreted Extracellular Vesicles Improved Survival in Mice Acutely Exposed to Myelosuppressive Doses of Ionizing Radiation

In cases of accidental high-dose total-body irradiation (TBI), acute radiation syndrome (ARS) can cause death. We reported that the thrombopoietin receptor agonist romiplostim (RP) has the potential to completely rescue mice exposed to lethal TBI. Extracellular vesicles (EVs) are involved in cell-to-cell communication, and the mechanism of RP action may be related to EVs that reflect the radio-mitigative information. We investigated the radio-mitigative effects of EVs on mice with severe ARS. C57BL/6 mice exposed to lethal TBI were treated with RP, and the EVs were isolated from the serum and intraperitoneally injected into other mice with severe ARS. The 30-day survival rate of lethal TBI mice drastically improved by 50-100% with the administration of EVs in the sera collected weekly from the mice in which radiation damage was alleviated and mortality was avoided by the administration of RP. Four responsive miRNAs, namely, miR-144-5p, miR-3620-5p, miR-6354, and miR-7686-5p showed significant expression changes in an array analysis. In particular, miR-144-5p was expressed only in the EVs of RP-treated TBI mice. Specific EVs may exist in the circulating blood of mice that escaped mortality with an ARS mitigator, and their membrane surface and endogenous molecules may be the key to the survival of mice with severe ARS.

Extracellular Vesicles in Breast Cancer: From Biology and Function to Clinical Diagnosis and Therapeutic Management

Breast cancer (BC) is the first worldwide most frequent cancer in both sexes and the most commonly diagnosed in females. Although BC mortality has been thoroughly declining over the past decades, there are still considerable differences between women diagnosed with early BC and when metastatic BC is diagnosed. BC treatment choice is widely dependent on precise histological and molecular characterization. However, recurrence or distant metastasis still occurs even with the most recent efficient therapies. Thus, a better understanding of the different factors underlying tumor escape is mainly mandatory. Among the leading candidates is the continuous interplay between tumor cells and their microenvironment, where extracellular vesicles play a significant role. Among extracellular vesicles, smaller ones, also called exosomes, can carry biomolecules, such as lipids, proteins, and nucleic acids, and generate signal transmission through an intercellular transfer of their content. This mechanism allows tumor cells to recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination. By reciprocity, stromal cells can also use exosomes to profoundly modify tumor cell behavior. This review intends to cover the most recent literature on the role of extracellular vesicle production in normal and cancerous breast tissues. Specific attention is paid to the use of extracellular vesicles for early BC diagnosis, follow-up, and prognosis because exosomes are actually under the spotlight of researchers as a high-potential source of liquid biopsies. Extracellular vesicles in BC treatment as new targets for therapy or efficient nanovectors to drive drug delivery are also summarized.

A review of the regulatory mechanisms of extracellular vesicles-mediated intercellular communication

Extracellular vesicles (EVs) are small, membrane-bound structures that are released from cells into the surrounding environment. These structures can be categorized as exosomes, microvesicles, or apoptotic vesicles, and they play an essential role in intercellular communication. These vesicles are attracting significant clinical interest as they offer the potential for drug delivery, disease diagnosis, and therapeutic intervention. To fully understand the regulation of intercellular communication through EVs, it is essential to investigate the underlying mechanisms. This review aims to provide a summary of the current knowledge on the intercellular communications involved in EV targeting, binding, and uptake, as well as the factors that influence these interactions. These factors include the properties of the EVs, the cellular environment, and the recipient cell. As the field of EV-related intercellular communication continues to expand and techniques improve, we can expect to uncover more information about this complex area, despite the current limitations in our knowledge.

Radiotherapy-induced tumor physical microenvironment remodeling to overcome immunotherapy resistance

The clinical benefits of immunotherapy are proven in many cancers, but a significant number of patients do not respond well to immunotherapy. The tumor physical microenvironment (TpME) has recently been shown to affect the growth, metastasis and treatment of solid tumors. The tumor microenvironment (TME) has unique physical hallmarks: 1) unique tissue microarchitecture, 2) increased stiffness, 3) elevated solid stress, and 4) elevated interstitial fluid pressure (IFP), which contribute to tumor progression and immunotherapy resistance in a variety of ways. Radiotherapy, a traditional and powerful treatment, can remodel the matrix and blood flow associated with the tumor to improve the response rate of immune checkpoint inhibitors (ICIs) to a certain extent. Herein, we first review the recent research advances on the physical properties of the TME and then explain how TpME is involved in immunotherapy resistance. Finally, we discuss how radiotherapy can remodel TpME to overcome immunotherapy resistance.

Enhancing the Cellular Production of Extracellular Vesicles for Developing Therapeutic Applications

Extracellular vesicles (EVs) have various advantageous properties, including a small size, high biocompatibility, efficient cargo loading, and precise cell targeting ability, making them promising tools for therapeutic development. EVs have been increasingly explored for applications like drug delivery. However, due to limited cellular secretion rates of EVs, wide-scale clinical applications are not achievable. Therefore, substantial strategies and research efforts have been devoted to increasing cellular secretion rates of EVs. This review describes various studies exploring different methods to increase the cellular production of EVs, including the application of electrical stimulus, pharmacologic agents, electromagnetic waves, sound waves, shear stress, cell starvation, alcohol, pH, heat, and genetic manipulation. These methods have shown success in increasing EV production, but careful consideration must be given as many of these strategies may alter EV properties and functionalities, and the exact mechanisms causing the increase in cellular production of EVs is generally unknown. Additionally, the methods' effectiveness in increasing EV secretion may diverge with different cell lines and conditions. Further advancements to enhance EV biogenesis secretion for therapeutic development is still a significant need in the field.

Prevention of Radiation-Induced Bladder Injury: A Murine Study Using Captopril

PURPOSE

Pelvic radiation therapy (RT) can cause debilitating bladder toxicities but few clinical interventions exist to prevent injury or alleviate symptoms. From a large genome-wide association study in patients with prostate cancer it was previously reported that SNPs tagging AGT, part of the renin-angiotensin system (RAS), correlated with patient-reported late hematuria, identifying a potential targetable pathway to prevent RT-induced bladder injury. To investigate this association, we performed a preclinical study to determine whether RAS modulation protected the bladder against RT injury.

METHODS AND MATERIALS

C57BL/6 male mice were treated with an oral angiotensin converting enzyme inhibitor (ACEi: 0.3g/L captopril) 5 days before focal bladder X-irradiation with either single dose (SD) 30 Gy or 3 fractions of 8 Gy (8 Gy × 3 in 5 days). RT was delivered using XStrahl SARRP Muriplan CT-image guidance with parallel-opposed lateral beams. ACEi was maintained for 20 weeks post RT. Bladder toxicity was assessed using assays to identify local injury that included urinalysis, functional micturition, bladder-released exosomes, and histopathology, as well as an assessment of systemic changes in inflammatory-mediated circulating immune cells.

RESULTS

SD and fractionated RT increased urinary frequency and reduced the volume of individual voids at >14 weeks, but not at 4 weeks, compared with nonirradiated animals. Urothelial layer width was positively correlated with mean volume of individual voids (P = .0428) and negatively correlated with number of voids (P = .028), relating urothelial thinning to changes in RT-mediated bladder dysfunction. These chronic RT-induced changes in micturition patterns were prevented by captopril treatment. Focal bladder irradiation significantly increased the mean particle count of urine extracellular vesicles and the monocyte and neutrophil chemokines CCL2 and MIP-2, and the proportions of circulating inflammatory-mediated neutrophils and monocytes, which was also prevented by captopril. Exploratory transcriptomic analysis of bladder tissue implicated inflammatory and erythropoietic pathways.

CONCLUSIONS

This study demonstrated that systemic modulation of the RAS protected against and alleviated RT-induced late bladder injury but larger confirmatory studies are needed.

Nucleic acid drug vectors for diagnosis and treatment of brain diseases

Nucleic acid drugs have the advantages of rich target selection, simple in design, good and enduring effect. They have been demonstrated to have irreplaceable superiority in brain disease treatment, while vectors are a decisive factor in therapeutic efficacy. Strict physiological barriers, such as degradation and clearance in circulation, blood-brain barrier, cellular uptake, endosome/lysosome barriers, release, obstruct the delivery of nucleic acid drugs to the brain by the vectors. Nucleic acid drugs against a single target are inefficient in treating brain diseases of complex pathogenesis. Differences between individual patients lead to severe uncertainties in brain disease treatment with nucleic acid drugs. In this Review, we briefly summarize the classification of nucleic acid drugs. Next, we discuss physiological barriers during drug delivery and universal coping strategies and introduce the application methods of these universal strategies to nucleic acid drug vectors. Subsequently, we explore nucleic acid drug-based multidrug regimens for the combination treatment of brain diseases and the construction of the corresponding vectors. In the following, we address the feasibility of patient stratification and personalized therapy through diagnostic information from medical imaging and the manner of introducing contrast agents into vectors. Finally, we take a perspective on the future feasibility and remaining challenges of vector-based integrated diagnosis and gene therapy for brain diseases.

Small extracellular vesicles from mesenchymal stem cells: A potential Weapon for chronic non-healing wound treatment

Chronic non-healing wounds have posed a severe threat to patients mentally and physically. Behavior dysregulation of remaining cells at wound sites is recognized as the chief culprit to destroy healing process and hinders wound healing. Therefore, regulating and restoring normal cellular behavior is the core of chronic non-healing wound treatment. In recent years, the therapy with mesenchymal stem cells (MSCs) has become a promising option for chronic wound healing and the efficacy has increasingly been attributed to their exocrine functions. Small extracellular vesicles derived from MSCs (MSC-sEVs) are reported to benefit almost all stages of wound healing by regulating the cellular behavior to participate in the process of inflammatory response, angiogenesis, re-epithelization, and scarless healing. Here, we describe the characteristics of MSC-sEVs and discuss their therapeutic potential in chronic wound treatment. Additionally, we also provide an overview of the application avenues of MSC-sEVs in wound treatment. Finally, we summarize strategies for large-scale production and engineering of MSC-sEVs. This review may possibly provide meaningful guidance for chronic wound treatment with MSC-sEVs.

Exosome secretion and cellular response of DU145 and PC3 after exposure to alpha radiation

Exosomes are spherical membrane nanovesicles secreted from cells, and they play an important role in tumor immune response, metastasis, angiogenesis, and survival. Studies investigating exosomes isolated from cells exposed to photon radiation commonly used in conventional radiotherapy demonstrate the influence of this type of radiation on exosome characteristics and secretion. There is currently no research investigating the effects of densely ionizing particles such as protons and alpha radiation on exosomes. Thus we have evaluated the cellular response of human prostate cancer cells exposed to 0, 2, and 6 Gy of alpha radiation emitted from the Am-241 source. Irradiated PC3 and DU145 cell lines, characterized by differences in radiosensitivity, were studied using apoptosis, LDH, and IL-6 assays. Additionally, the corresponding concentration and size of isolated exosomes were measured using NTA. We found that exposure to ionizing radiation resulted in gross changes in viability and cell damage. There were increased amounts of apoptotic or necrotic cells as a function of radiation dose. We demonstrated that irradiated PC3 cells secrete higher quantities of exosomes compared to DU145 cells. Additionally, we also found no statistical difference in exosome size for control and irradiated cells.

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.

The distinct roles of exosomes in innate immune responses and therapeutic applications in cancer

The innate immune system is one of the major constituents of the host's defense against invading pathogens and extracellular vesicles (EVs) are involved in regulating its responses. Exosomes, a subclass of EVs, released from eukaryotic cells, contribute to intracellular communication and drive various biological processes by transferring nuclei acids, proteins, lipids, and carbohydrates between cells, protecting cargo from enzymatic degradation and immune recognition and consequent elimination by the immune system. A growing body of evidence has revealed that exosomes produced from host cells, infected cells, tumor cells, and immune cells regulate innate immune signaling and responses and thus play a significant role in the propagation of pathogens. Immune cells can recognize exosomes-bearing components including DNA strands, viral RNAs, and even proteins by various mechanisms such as through Toll-like receptor/NF-κB signaling, inducing cytokine production and reprogramming the innate immune responses, immunosuppression or immunesupportive. There is persuasive preclinical and clinical evidence that exosomes are therapeutic strategies for immunotherapy, cancer vaccine, drug-delivery system, and diagnostic biomarker. However, further scrutiny is essential to validate these findings. In this review, we describe the current facts on the regulation of innate immune responses by exosomes. We also describe the translational application of exosomes as cancer-therapy agents and immunotherapy.

Quantitative Expression of SFN, lncRNA CCDC18-AS1, and lncRNA LINC01343 in Human Breast Cancer as the Regulator Biomarkers in a Novel ceRNA Network: Based on Bioinformatics and Experimental Analyses

Breast cancer (BC) is one of the leading cancers in the world, which has become an increasing serious problem. In this context, reports demonstrate that some long noncoding RNAs (lncRNAs) play significant regulatory roles in breast tumorigenesis and BC progression via various pathways and act as endogenous RNAs. Finding their dysregulation in cancer and evaluating their interaction with other molecules, such as short noncoding RNAs “microRNA (miRNAs)” as well as various genes, are the most important parts in cancer diagnostics. In this study, after performing GSEA and microarray analysis on the GSE71053 dataset, a new ceRNA network of CCDC18-AS1, LINC01343, hsa-miR4462, and SFN in BC was detected by bioinformatics analysis. Therefore, the expression of SFN, CCDC18-AS1, and LINC01343 was quantitatively measured in 24 BC and normal paired tissues using qRT-PCR. CCDC18-AS1, LINC01343, and SFN were expressed higher in BC than in the control (normal paired) tissues based on qRT-PCR data. Furthermore, a significant positive correlation was observed between CCDC18-AS1 and LINC01343 expression in the samples investigated in this study. The investigation of clinicopathological parameters showed that SFN was highly expressed in tumor size of <5 cm and in nonmenopausal ages, while CCDC18-AS1 and LINC01343 indicated a high expression in stages II-III and III of BC, respectively. The overall survival analysis displayed high and low survival in patients with high expression of SFN and CCDC18-AS1, respectively. The ROC curve analysis disclosed that SFN, CCDC18-AS1, and LINC01343 might be suggested as potential biological markers in BC patients. The high expression of CCDC18-AS1, LINC01343, and SFN in BC samples suggests their potential role in BC tumorigenesis and could be considered hallmarks for the diagnosis and prognosis of BC, although this will require further clinical investigations.

Radiated glioblastoma cell-derived exosomal circ_0012381 induce M2 polarization of microglia to promote the growth of glioblastoma by CCL2/CCR2 axis

Background

Radiotherapy is the primary therapeutic option for glioblastoma. Some studies proved that radiotherapy increased the release of exosomes from cells. The mechanism by which these exosomes modify the phenotype of microglia in the tumor microenvironment to further determine the fate of irradiated glioblastoma cells remains to be elucidated.

Methods

We erected the co-culture system of glioblastoma cells and microglia. After radiation, we analyzing the immunophenotype of microglia and the proliferation of radiated glioblastoma cells. By whole transcriptome sequencing, we analyzed of circRNAs in exosomes from glioblastoma cells and microglia. We used some methods, which included RT-PCR, dual-luciferase reporter, et al., to identify how circ_0012381 from radiated glioblastoma cell-derived exosomes regulated the immunophenotype of microglia to further affect the proliferation of radiated glioblastoma cells.

Results

Radiated glioblastoma cell-derived exosomes markedly induced M2 microglia polarization. These M2-polarized microglia promoted the proliferation of irradiated glioblastoma cells. Circ_0012381 expression was increased in the irradiated glioblastoma cells, and circ_0012381 entered the microglia via exosomes. Circ_0012381 induced M2 microglia polarization by sponging with miR-340-5p to increase ARG1 expression. M2-polarized microglia suppressed phagocytosis and promoted the growth of the irradiated glioblastoma cells by CCL2/CCR2 axis. Compared with the effects of radiotherapy alone, the inhibition of exosomes significantly inhibited the growth of irradiated glioblastoma cells in a zebrafish model.

Conclusions

Our data suggested that the inhibition of exosome secretion might represent a potential therapeutic strategy to increase the efficacy of radiotherapy in patients with glioblastoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03607-0.

Mechanism and clinical value of exosomes and exosomal contents in regulating solid tumor radiosensitivity

Radiotherapy is among the routine treatment options for malignant tumors. And it damages DNA and other cellular organelles in target cells by using ionizing radiation produced by various rays, killing the cells. In recent years, multiple studies have demonstrated that exosomes are mechanistically involved in regulating tumor formation, development, invasion and metastasis, and immune evasion. The latest research shows that radiation can affect the abundance and composition of exosomes as well as cell-to-cell communication. In the environment, exosome-carried miRNAs, circRNA, mRNA, and proteins are differentially expressed in cancer cells, while these molecules play a role in numerous biological processes, including the regulation of oncogene expression, mediation of signaling pathways in cancer cells, remodeling of tumor-related fibroblasts, regulation of cell radiosensitivity, and so forth. Therefore, elucidation of the mechanism underlying the role of exosomes in radiotherapy of malignant tumors is crucial for improving the efficacy of radiotherapy. This review will summarize the research advances in radiosensitivity of malignant tumors related to exosomes.

Exosomes Derived from Senescent Endothelial Cells Contain Distinct Pro-angiogenic miRNAs and Proteins

Exosomes from senescence cells play pivotal roles in endothelium dysfunction. We investigated the exosomal angiogenic cargo of endothelial cells (ECs) in a model of senescence in vitro. After inducing aging by H₂O₂, the expression of P53, P21, and P16 was investigated by western blotting, while the expression of FMR1, miR-21, and miR-126 were measured by real-time PCR (q-PCR). Oil Red O dye was used to stain cells. Acetylcholinesterase (AChE) assay, transmission electron microscopy (TEM), and western blotting characterized Exosomes. Exosomal miR-21, miR-126, matrix metallopeptidase-9 (MMP-9), and tumor necrosis factor- ɑ (TNF-ɑ) proteins were measured by Q-PCR and western blotting. A wound-healing assay was used to explore the effect of exosomes on ECs migration rate. The results showed that the expression of P53, P21, P16, FMR1, and miR-21 was increased in treated cells as compared with control cells (P < 0.05). In addition, the expression of miR-126 was decreased in treated cells (P < 0.05). The number of Oil Red O-positive-treated cells increased (P < 0.05). The AChE activity of exosomes from treated cells was increased (P < 0.05). In comparison with control cells, an increase in the expression levels of exosomal miR-21 and TNF-ɑ of treated cells coincided with a decrease in the expression levels of miR-126 and MMP-9 levels (P < 0.05). We found that the migration rate of ECs co-cultured with exosomes from treated cells was decreased (P < 0.05). The data indicate ECs under H₂O₂ condition produce exosomes with distinct cargo that may be useful as a biomarker of age-related vascular disease.

Inhibition of extracellular vesicle biogenesis in tumor cells: A possible way to reduce tumorigenesis

Most eukaryotic cells secrete extracellular vesicles (EVs), which contribute to intracellular communication through transferring different biomolecules such as proteins, RNAs, and lipids to cells. Two main types of EVs are exosomes and microvesicles. Exosomes originate from multivesicular bodies, while microvesicles are shed from the plasma membrane. Mechanisms of exosomes and microvesicle biogenesis/trafficking are complex and many molecules are involved in their biogenesis and secretion. Tumor-derived EVs contain oncogenic molecules that promote tumor growth, metastasis, immune surveillance, angiogenesis, and chemoresistance. A growing body of evidence indicates various compounds can inhibit biogenesis and secretion of EVs from cells and several experiments were conducted to use EVs-inhibitors for understanding the biology of the cells or for understanding the pathology of several diseases like cancer. However, the nontargeting effects of drugs/inhibitors remain a concern. Our current knowledge of EVs biogenesis and their inhibition from tumor cells may provide an avenue for cancer management. In this review, we shed light on exosomes and microvesicles biogenesis, key roles of tumor-derived EVs, and discuss methods used to inhibition of EVs by different inhibitors.

Irradiated cell-derived exosomes transmit essential molecules inducing radiotherapy resistance

Radio-resistance has always been a major obstacle in radiation therapy (RT) progress. Radiotherapy (RT) leads to changes in the contents of released exosomes. The researches have shown that irradiated cell-derived exosomes influence recipient cell proliferation, migration, cell cycle arrest and apoptosis. All evidence indicates that exosomes play a significant role in radio-resistance. In this review, we describe the potential role of exosomes in cancer. We summarize that the irradiated cell-derived exosomes influence radio-resistance in recipient cells by three main mechanisms: 1) enhancing DNA repair, 2) regulating cell death signalling pathways, 3) inducing cancer cells to exhibit stem cell properties. We also discuss that the origin of the phenomenon might be the changes of molecular mechanisms of irradiated cell-derived exosomes formation affected by RT. Further, targeting exosomes as an adjuvant therapy might be a promising way for cancer treatments.

BHMPS Inhibits Breast Cancer Migration and Invasion by Disrupting Rab27a-Mediated EGFR and Fibronectin Secretion

Simple Summary

Numerous studies targeting Rab GTPases and its multiple effectors have been attempted since exocytosis has been shown to alter tumor malignancy by modulating cancer cell behavior and tumor microenvironment. Here, we demonstrated that BHMPS inhibits migration and invasion of breast cancer cells by blocking the interaction between Rab27a and Slp4. BHMPS interfered with vesicle trafficking and secretion by decreasing FAK and JNK activation. In addition, BHMPS suppressed tumor growth in Rab27a-overexpressing MDA-MB-231 xenograft mice. This study highlighted the importance of understanding the mechanisms of Rab27a-mediated metastasis in improving the therapeutic options for metastatic cancers.

Abstract

Our previous work demonstrated that (E)-N-benzyl-6-(2-(3, 4-dihydroxybenzylidene) hydrazinyl)-N-methylpyridine-3-sulfonamide (BHMPS), a novel synthetic inhibitor of Rab27aSlp(s) interaction, suppresses tumor cell invasion and metastasis. Here, we aimed to further investigate the mechanisms of action and biological significance of BHMPS. BHMPS decreased the expression of epithelial-mesenchymal transition transcription factors through inhibition of focal adhesion kinase and c-Jun N-terminal kinase activation, thereby reducing the migration and invasion of breast cancer. Additionally, knockdown of Rab27a inhibited tumor migration, with changes in related signaling molecules, whereas overexpression of Rab27a reversed this phenomenon. BHMPS effectively prevented the interaction of Rab27a and its effector Slp4, which was verified by co-localization, immunoprecipitation, and in situ proximity ligation assays. BHMPS decreased the secretion of epidermal growth factor receptor and fibronectin by interfering with vesicle trafficking, as indicated by increased perinuclear accumulation of CD63-positive vesicles. Moreover, administration of BHMPS suppressed tumor growth in Rab27a-overexpressing MDA-MB-231 xenograft mice. These findings suggest that BHMPS may be a promising candidate for attenuating tumor migration and invasion by blocking Rab27a-mediated exocytosis.

Inhibitory effects of gallic acid on the activity of exosomal secretory pathway in breast cancer cell lines: A possible anticancer impact

Introduction: Breast cancer cells produce exosomes that promote tumorigenesis. The anticancer properties of gallic acid have been reported. However, the mechanism underlying its anticancer effect on the exosomal secretory pathway is still unclear. We investigated the effect of gallic acid on exosome biogenesis in breast cancer cell lines. Methods: The cytotoxic effect of gallic acid on MCF-10a, MCF-7, and MDA-MD-231 cells was measured by MTT assay after 48 hours treatment. Expression of miRNAs including miRNA-21, -155, and 182 as well as exosomal genes such as Rab27a, b, Rab11, Alix, and CD63; along with HSP-70 (autophagy gene), was determined using Q-PCR. The subcellular distribution of it was monitored by flow cytometry analysis. Isolated exosomes were characterized by transmission and scanning electron microscopes and flow cytometry. Acetylcholinesterase activity is used to measure the number of exosomes in supernatants. In addition, autophagy markers including LC3 and P62 were measured by ELISA. Results: Data showed that gallic acid was cytotoxic to cells (P < 0.05). Gallic acid modulated expression of miRNAs and down-regulated transcript levels of exosomal genes and up-regulated the HSP-70 gene in three cell lines (P < 0.05). The surface CD63/total CD63 ratio as well as acetylcholinesterase activity decreased in treated cells (P < 0.05). The protein level of LC3 was increased in three cell lines, while the expression of P62 increased in MCF-7 and MDA-MB-231 cancer cell lines. Conclusion: Together, gallic acid decreased the activity of the exosomal secretory pathway in breast cancer cell lines, providing evidence for its anti-cancer effects.

Current Strategies for Cancer Cell-Derived Extracellular Vesicles for Cancer Therapy

Cancer cell-derived extracellular vesicles (CEVs), a novel type of therapeutic agent in cancer treatment, can be prepared from the autocrine secretion of various cancer cells, the direct extraction of cancer cells and the combination of cancer cell-derived membranes with advanced materials. With various bioactive molecules, exosomes are produced by cells for intercellular communication. Although cancer cell-derived exosomes are known to inhibit tumor apoptosis and promote the progression of cancer, researchers have developed various innovative strategies to prepare anti-tumor vesicles from cancer cells. With current strategies for anti-tumor vesicles, four different kinds of CEVs are classified including irradiated CEVs, advanced materials combined CEVs, chemotherapeutic drugs loaded CEVs and genetically engineered CEVs. In this way, CEVs can not only be the carriers for anti-tumor drugs to the target tumor area but also act as immune-active agents. Problems raised in the strategies mainly concerned with the preparation, efficacy and application. In this review, we classified and summarized the current strategies for utilizing the anti-tumor potential of CEVs. Additionally, the challenges and the prospects of this novel agent have been discussed.

The Advancing Roles of Exosomes in Breast Cancer

Breast cancer (BC) develops from breast tissue and is the most common aggressive malignant tumor in women worldwide. Although advanced treatment strategies have been applied and reduced current mortality rates, BC control remains unsatisfactory. It is essential to elucidate the underlying molecular mechanisms to assist clinical options. Exosomes are a type of extracellular vesicles and mediate cellular communications by delivering various biomolecules (oncogenes, oncomiRs, proteins, and even pharmacological compounds). These bioactive molecules can be transferred to change the transcriptome of target cells and influence tumor-related signaling pathways. Extensive studies have implicated exosomes in BC biology, including therapeutic resistance and the surrounding microenvironment. This review focuses on discussing the functions of exosomes in tumor treatment resistance, invasion and metastasis of BC. Moreover, we will also summarize multiple interactions between exosomes and the BC tumor microenvironment. Finally, we propose promising clinical applications of exosomes in BC.

Current Clinical Application of Mesenchymal Stem Cells in the Treatment of Severe COVID-19 Patients: Review

Coronavirus-2019 disease is a newly diagnosed infectious disease, which is caused by the severe acute respiratory syndrome corona virus-2. It spreads quickly and has become a major public health problem throughout the world. When the viral structural spike protein binds to the angiotensin-converting enzyme-2 receptor of the host cell membrane, the virus enters into host cells. The virus primarily affects lung epithelial cells or other target cells that express angiotensin-converting enzyme-2 receptors in COVID-19 patients. Chemokines released by the host cells stimulate the recruitment of different immune cells. A cytokine storm occurs when a high amount of pro-inflammatory cytokines are produced as a result of the accumulation of immune cells. In COVID-19 patients, cytokine storms are the leading cause of severe acute respiratory distress syndrome. Mesenchymal stem cells are multipotent and self-renewing adult stem cells, which are obtained from a variety of tissues including bone marrow, adipose tissue, Warthon's jelly tissue, and amniotic fluid. Mesenchymal stem cells primarily exert their important therapeutic effects through 2 mechanisms: immunoregulatory effects and differentiation capacity. Mesenchymal stem cells can release several cytokines via paracrine mechanism or by direct interaction with white blood cells such as natural killer cells, T-lymphocytes, B-lymphocytes, natural killer cells, and macrophages, resulting in immune system regulation. Mesenchymal stem cells may help to restore the lung microenvironment, preserve alveolar epithelial cells, prevent lung fibrosis, and treat pulmonary dysfunction that is caused by COVID-19 associated pneumonia. Mesenchymal stem cells therapy may suppress aggressive inflammatory reactions and increase endogenous restoration by improving the pulmonary microenvironment. Furthermore, clinical evidence suggests that intravenous injection of mesenchymal stem cells may radically reduce lung tissue damage in COVID-19 patients. With the advancement of research involving mesenchymal stem cells for the treatment of COVID-19, mesenchymal stem cells therapy may be the main strategy for reducing the recent pandemic.

3D Breast Tumor Models for Radiobiology Applications

Breast cancer is a leading cause of cancer-associated death in women. The clinical management of breast cancers is normally carried out using a combination of chemotherapy, surgery and radiation therapy. The majority of research investigating breast cancer therapy until now has mainly utilized two-dimensional (2D) in vitro cultures or murine models of disease. However, there has been significant uptake of three-dimensional (3D) in vitro models by cancer researchers over the past decade, highlighting a complimentary model for studies of radiotherapy, especially in conjunction with chemotherapy. In this review, we underline the effects of radiation therapy on normal and malignant breast cells and tissues, and explore the emerging opportunities that pre-clinical 3D models offer in improving our understanding of this treatment modality.

Small extracellular vesicles in cancer

Extracellular vesicles (EV) are lipid-bilayer enclosed vesicles in submicron size that are released from cells. A variety of molecules, including proteins, DNA fragments, RNAs, lipids, and metabolites can be selectively encapsulated into EVs and delivered to nearby and distant recipient cells. In tumors, through such intercellular communication, EVs can regulate initiation, growth, metastasis and invasion of tumors. Recent studies have found that EVs exhibit specific expression patterns which mimic the parental cell, providing a fingerprint for early cancer diagnosis and prognosis as well as monitoring responses to treatment. Accordingly, various EV isolation and detection technologies have been developed for research and diagnostic purposes. Moreover, natural and engineered EVs have also been used as drug delivery nanocarriers, cancer vaccines, cell surface modulators, therapeutic agents and therapeutic targets. Overall, EVs are under intense investigation as they hold promise for pathophysiological and translational discoveries. This comprehensive review examines the latest EV research trends over the last five years, encompassing their roles in cancer pathophysiology, diagnostics and therapeutics. This review aims to examine the full spectrum of tumor-EV studies and provide a comprehensive foundation to enhance the field. The topics which are discussed and scrutinized in this review encompass isolation techniques and how these issues need to be overcome for EV-based diagnostics, EVs and their roles in cancer biology, biomarkers for diagnosis and monitoring, EVs as vaccines, therapeutic targets, and EVs as drug delivery systems. We will also examine the challenges involved in EV research and promote a framework for catalyzing scientific discovery and innovation for tumor-EV-focused research.

Role of Mitochondria in Radiation Responses: Epigenetic, Metabolic, and Signaling Impacts

Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology studies reveal that the outcomes of exposures to ionizing radiation (IR) highly depend on activation and regulation through other molecular components of organelles that determine cell survival and proliferation capacities. As typical epigenetic-regulated organelles and central power stations of cells, mitochondria play an important pivotal role in those responses. They direct cellular metabolism, energy supply and homeostasis as well as radiation-induced signaling, cell death, and immunological responses. This review is focused on how energy, dose and quality of IR affect mitochondria-dependent epigenetic and functional control at the cellular and tissue level. Low-dose radiation effects on mitochondria appear to be associated with epigenetic and non-targeted effects involved in genomic instability and adaptive responses, whereas high-dose radiation effects (>1 Gy) concern therapeutic effects of radiation and long-term outcomes involving mitochondria-mediated innate and adaptive immune responses. Both effects depend on radiation quality. For example, the increased efficacy of high linear energy transfer particle radiotherapy, e.g., C-ion radiotherapy, relies on the reduction of anastasis, enhanced mitochondria-mediated apoptosis and immunogenic (antitumor) responses.

The impact of neoadjuvant concurrent chemoradiation on exosomal markers (CD63 and CD9) expression and their prognostic significance in patients with rectal adenocarcinoma

Introduction: Exosomes have pivotal roles in cancer development. The impact of neoadjuvant concurrent chemoradiation (NCCR) on exosomal markers (CD63 and CD9) expression and their prognostic significance in patients with rectal adenocarcinoma are yet to be explored.

Materials and Methods: Between 2015 and 2018, 33 patients had rectal adenocarcinoma treated with NCCR and had pre-NCCR biopsy and post-NCCR resected rectum. CD63 and CD9 expression was assessed by immunohistochemistry (IHC). The short-term surrogate endpoint neoadjuvant rectal (NAR) score was used for assessment of prognostic significance. Un-Paired t-test was used for statistical analysis.

Results: The mean tumor CD63 and CD9 scores in pre-NCCR biopsy vs. post-NCCR resected rectum were 106 vs. 165 (P = 0.0022) and 136 vs. 215 (P < 0.0001) respectively. The mean tumor CD63 and CD9 scores respectively in pre-NCCR biopsy was 99 and 130 in patients with low-intermediate NAR score compared to 117 and 144 in patients with high NAR score (P = 0.4934) (P = 0.5519). The mean tumor CD63 and CD9 scores respectively in post-NCCR resected rectum was 155 and 205 in patients with low-intermediate NAR score compared to 180 and 230 in patients with high NAR score (P = 0.3793) (P = 0.2837).

Conclusions: The expression of the exosomal markers (CD63 and CD9) increased in patients with rectal adenocarcinoma after treatment with NCCR. The exosomal markers (CD63 and CD9) may have a prognostic significance. There was a trend for higher CD63 and CD9 expression in patients with high NAR score compared with low-intermediate NAR scores. The lack of statistical significance is likely due to the small sample size.

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.

Extracellular Vesicles under Oxidative Stress Conditions: Biological Properties and Physiological Roles

Under physio-pathological conditions, cells release membrane-surrounded structures named Extracellular Vesicles (EVs), which convey their molecular cargo to neighboring or distant cells influencing their metabolism. Besides their involvement in the intercellular communication, EVs might represent a tool used by cells to eliminate unnecessary/toxic material. Here, we revised the literature exploring the link between EVs and redox biology. The first proof of this link derives from evidence demonstrating that EVs from healthy cells protect target cells from oxidative insults through the transfer of antioxidants. Oxidative stress conditions influence the release and the molecular cargo of EVs that, in turn, modulate the redox status of target cells. Oxidative stress-related EVs exert both beneficial or harmful effects, as they can carry antioxidants or ROS-generating enzymes and oxidized molecules. As mediators of cell-to-cell communication, EVs are also implicated in the pathophysiology of oxidative stress-related diseases. The review found evidence that numerous studies speculated on the role of EVs in redox signaling and oxidative stress-related pathologies, but few of them unraveled molecular mechanisms behind this complex link. Thus, the purpose of this review is to report and discuss this evidence, highlighting that the analysis of the molecular content of oxidative stress-released EVs (reminiscent of the redox status of originating cells), is a starting point for the use of EVs as diagnostic and therapeutic tools in oxidative stress-related diseases.

Engineering of Extracellular Vesicles Based on Payload Changes for Tissue Regeneration

In the field of tissue regeneration and tissue engineering, many years ago, various nano to macroscopic-sized materials have been used to reduce inflammation and restore damaged tissue. Whether it is safe to study the regeneration of all tissues based on the biological mechanisms of an organism composed of cells is still debated, and studies using extracellular vesicles derived from cells have become popular in the past decade. It has been reported that exosomes with a size of 100 nm or less, which plays an important role in cell-cell communication, contain various factors, such as proliferation, anti-inflammatory, and growth factors. In addition, the payload of exosomes varies depending on the parent cell and the recipient cell, and a technology to differentiate the selective payload must treat specific diseases. In this review, we examined the current trends in research using exosomes derived from cells or tissues and analyzed various research reports on factors that can affect tissue regeneration.

Bystander effects induced by electron beam-irradiated MCF-7 cells: a potential mechanism of therapy resistance

PURPOSE

The distinct direct and non-targeting effects of electron beam radiation on MCF-7 cells remain obscure. We aimed to investigate the effect of electron beam irradiation (EBI) and conditioned media (CM) of the irradiated MCF-7 cells on MCF-7 cells. The cytotoxic effects of CM from irradiated MCF-7 cells on the mesenchymal stem cells and human umbilical vein endothelial cells (HUVECs) were also examined.

METHODS

Cell viability and apoptosis were assayed via MTT and flow cytometry analysis, respectively. The production of ROS (reactive oxygen species) was evaluated by the chemical fluorometric method, while the amount of extracellular vesicles was detected via acetylcholinesterase activity assay. Expression of genes involved in apoptosis, including caspase-3, -8, -9, and stemness such as Sox-2 and Oct-4, were calculated through qPCR. The wound healing rate of cells was monitored via in vitro scratch assay.

RESULTS

Compared to the control group, EBI groups showed decreased cell viability but increased apoptosis and ROS as well as acetylcholinesterase activity dose-dependently (P < 0.05). Concurrently with increasing the dose of the electron beam, the transcript levels of apoptotic genes (caspase-3, -8, -9) and stemness-related genes (Sox-2 and Oct-4) were up-regulated following EBI. The wound healing rate of irradiated MCF-7 cells increased dose-dependently (P < 0.05). Similar results were observed after treatment with CM from irradiated MCF-7 cells. Additionally, CM from irradiated MCF-7 cells decreased the viability of MCF-7 cells, mesenchymal stem cells, and HUVECs (P < 0.05).

CONCLUSION

MCF-7 cells treated with an electron beam and CMs from irradiated MCF-7 cells exhibit an up-regulation in both genes involved in the apoptosis pathway and stemness. As a result, EBI can affect apoptosis and stemness in MCF-7 cells in direct and bystander manners. However, specific signaling pathways require careful evaluation to provide an understanding of the mechanisms involved in the EBI-induced alternation in tumor cell dynamics.

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.

Identification of low-dose radiation-induced exosomal circ-METRN and miR-4709-3p/GRB14/PDGFRα pathway as a key regulatory mechanism in Glioblastoma progression and radioresistance: Functional validation and clinical theranostic significance

Glioblastoma is a central nervous malignancy with a very poor prognosis. This study attempted to explore the role of exosomes induced by low-dose radiation-induced (ldrEXOs) and ldrEXOs-derived circ-METRN in glioblastoma progression and radioresistance at the molecular, cellular, animal, and clinical levels. Results in the present study revealed that low-dose radiation stimulated the secretion of ldrEXOs which delivered high levels of circ-METRN. And circ-METRN-abundant ldrEXOs increased the expression of γ-H2AX, indicating an efficient DNA damage-repair process in glioblastoma cells. The ldrEXOs-derived circ-METRN enhanced the glioblastoma progression and radioresistance via miR-4709-3p/GRB14/PDGFRα pathway. Up-regulating PDGFRα can rescue the tumor-promoting function of ldrEXOs in groups previously treated with inhibition of GRB14. Additionally, in-vivo experiments revealed that treatments with ldrEXOs promoted the growth of xenografted tumors and shortened the survival period. Furthermore, clinical researches indicated that circ-METRN may be transported into the bloodstream by exosomes in the early stages of fractionated radiotherapy. It has important clinical values to detect the serum exosomal circ-METRN in the early stage of radiotherapy, which is not only conducive to predict radioresistance and prognosis but also to assist MRI diagnosis in detecting the very early recurrence of glioblastoma. In summary, this study reveals for the first time that low-dose radiation-induced exosomal circ-METRN plays an oncogenic role in glioblastoma progression and radioresistance through miR-4709-3p/GRB14/PDGFRα pathway, providing mechanistic insights into the roles of circRNAs and a valuable marker for therapeutic targets in glioblastoma.

Small extracellular vesicles deliver TGF-β1 and promote adriamycin resistance in breast cancer cells

Chemotherapeutic resistance is a major obstacle in the control of advanced breast cancer (BCa). We have previously shown that small extracellular vesicles (sEVs) can transmit adriamycin resistance between BCa cells. Here, we describe that sEV‐mediated TGF‐β1 intercellular transfer is involved in the drug‐resistant transmission. sEVs were isolated and characterized from both sensitive and resistant cells. sEVs derived from the resistant cells were incubated with the sensitive cells and resulted in transmitting the resistant phenotype to the recipient cells. Cytokine antibody microarray revealed that most metastasis‐associated cytokines present at the high levels in sEVs from the resistant cells compared with their levels in sEVs from the sensitive cells, particularly TGF‐β1 is enriched in sEVs from the resistant cells. The sEV‐mediated TGF‐β1 intercellular transfer led to increasing Smad2 phosphorylation and improving cell survival by suppressing apoptosis and enhancing cell mobility. Furthermore, sEV‐mediated drug‐resistant transmission by delivering TGF‐β1 was validated using a zebrafish xenograft tumor model. These results elaborated that sEV‐mediated TGF‐β1 intercellular transfer contributes to adriamycin resistance in BCa.

The Hypoxic Microenvironment of Breast Cancer Cells Promotes Resistance in Radiation Therapy

The American Cancer Society has estimated an expected 279,100 new breast cancer cases, and an expected 42,690 breast cancer deaths in the U.S. for the year 2020. This includes an estimated 276,480 women who are expected to be diagnosed. Radiation therapy, also called ionizing radiation therapy, is one of the most frequently used methods in the treatment of breast cancer. While radiation therapy is used in the treatment of more than 50% of all cancer cases, tumor resistance to ionizing radiation presents a major challenge for effective cancer treatment. Most tumor cells are in a hypoxic microenvironment that promotes resistance to radiation therapy. In addition to radiation resistance, the hypoxic microenvironment also promotes cancer proliferation and metastasis. In this review, we will discuss the hypoxic microenvironment of breast cancer tumors, related signaling pathways, breast cancer stem-like cells, and the resistance to radiation therapy. Recent developments in our understanding of tumor hypoxia and hypoxic pathways may assist us in developing new strategies to increase cancer control in radiation therapy.

Extracellular vesicle-transferred long noncoding RNAs in bladder cancer

Extracellular vesicles (EVs) secreted by a variety of cells, including cancer cells, in the tumor microenvironment play crucial roles in cancer progression by transferring molecular cargos. Emerging evidence indicates that long noncoding RNAs (lncRNAs) are important biomolecules that can be transferred by EVs to modulate cancer development. The potential clinical application of EV-transferred lncRNAs in biological fluids for cancer diagnosis has also been verified. Over the past decade, research on the biological roles and applications of EVs and their contents in human cancers has reached new heights. Therefore, a detailed discussion of the roles of EV-transferred lncRNAs in various cancers, including bladder cancer (BC), will provide a novel strategy for cancer diagnosis and therapy. In this review, we summarized and discussed the current studies on the detection technologies of EV-transferred lncRNAs. The diagnostic values of EV-transferred lncRNAs in various biological fluids, including urine, serum, and plasma, for BC diagnosis and prognosis were compared. Moreover, the biofunctional roles and clinical applications of these EV-transferred lncRNAs in BC were further discussed. In addition, we also highlighted the research directions and suggestions for future research on BC-associated EV-transferred lncRNAs. In conclusion, BC-associated EV-transferred lncRNAs show significant potential as noninvasive biomarkers or therapeutic targets for BC diagnosis and treatment.

Rab27b contributes to radioresistance and exerts a paracrine effect via epiregulin in glioblastoma

Background

Radiotherapy is the standard treatment for glioblastoma (GBM). However, radioresistance of GBM cells leads to recurrence and poor patient prognosis. Recent studies suggest that secretion factors have important roles in radioresistance of tumor cells. This study aims to determine whether Rab27b, a small GTPase involved in secretory vesicle trafficking, plays a role in radioresistance of GBM.

Methods

Microarray analysis, cell viability analysis, apoptosis assay, immunostaining, and in vivo experiments were performed to assess the effect of Rab27b on radioresistance of GBM. We further investigated paracrine effects mediated by Rab27b after X-ray irradiation using coculture systems of glioma cell lines.

Results

Rab27b was specifically upregulated in irradiated U87MG cells. Furthermore, Rab27b knockdown decreased the proliferation of GBM cells after irradiation. Knockdown of Rab27b in U87MG cells combined with radiation treatment suppressed orthotopic tumor growth in the mouse brain and prolonged the survival of recipient mice. Interestingly, the co-upregulation of Rab27b and epiregulin (EREG), a member of the epidermal growth factor (EGF) family, correlated with radioresistance in glioma cell lines. Additionally, EREG, which was secreted from U87MG cells via Rab27b-mediated mechanism, activated EGF receptor and contributed to H4 cell proliferation in a paracrine manner.

Conclusions

Our results show that Rab27b mediates the radioresistance of highly malignant GBM cells. Rab27b promotes the proliferation of adjacent cells through EREG-mediated paracrine signaling after irradiation. Thus, the Rab27b-EREG pathway is a novel potential target to improve the efficacy of radiotherapy in GBM.

Emerging biogenesis technologies of extracellular vesicles for tissue regenerative therapeutics

Extracellular vesicles (EVs), including exosomes, carry the genetic packages of RNA, DNA, and proteins and are heavily involved in cell-cell communications and intracellular signalings. Therefore, EVs are spotlighted as therapeutic mediators for the treatment of injured and dysfunctional tissues as well as biomarkers for the detection of disease status and progress. Several key issues in EVs, including payload content and bioactivity, targeting and bio-imaging ability, and mass-production, need to be improved to enable effective therapeutics and clinical translation. For this, significant efforts have been made recently, including genetic modification, biomolecular and chemical treatment, application of physical/mechanical cues, and 3D cultures. Here we communicate those recent technological advances made mainly in the biogenesis process of EVs or at post-collection stages, which ultimately aimed to improve the therapeutic efficacy in tissue healing and disease curing and the possibility of clinical translation. This communication will help tissue engineers and biomaterial scientists design and produce EVs optimally for tissue regenerative therapeutics.