Mediation of radiation-induced bystander effect and epigenetic modification: The role of exosomes in cancer radioresistance.

Exosomes are nano-sized extracellular vesicles produced by almost all mammalian cells. They play an important role in cell-to-cell communication by transferring biologically active molecules from the cell of origin to the recipient cells. Ionizing radiation influences exosome production and molecular cargo loading. In cancer management, ionizing radiation is a form of treatment that exerts its cancer cytotoxicity by induction of DNA damage and other alterations to the targeted tissue cells. However, normal bystander non-targeted cells may exhibit the effects of ionizing radiation, a phenomenon called radiation-induced bystander effect (RIBE). The mutual communication between the two groups of cells (targeted and non-targeted) via radiation-influenced exosomes enables the exchange of radiosensitive molecules. This facilitates indirect radiation exposure, leading, among other effects, to epigenetic remodeling and subsequent adaptation to radiation. This review discusses the role exosomes play in epigenetically induced radiotherapy resistance through the mediation of RIBE.

Pilot screening of potential matrikines resulting from collagen breakages through ionizing radiation.

Little is known regarding radiation-induced matrikines and the possible degradation of extracellular matrix following therapeutic irradiation. The goal of this study was to determine if irradiation can cut collagen proteins at specific sites, inducing potentially biologically active peptides against cartilage cells. Chondrocytes cultured as 3D models were evaluated for extracellular matrix production. Bystander molecules were analyzed in vitro in the conditioned medium of X-irradiated chondrocytes. Preferential breakage sites were analyzed in collagen polypeptide by mass spectrometry and resulting peptides were tested against chondrocytes. 3D models of chondrocytes displayed a light extracellular matrix able to maintain the structure. Irradiated and bystander chondrocytes showed a surprising radiation sensitivity at low doses, characteristic of the presence of bystander factors, particularly following 0.1 Gy. The glycine-proline peptidic bond was observed as a preferential cleavage site and a possible weakness of the collagen polypeptide after irradiation. From the 46 collagen peptides analyzed against chondrocytes culture, 20 peptides induced a reduction of viability and 5 peptides induced an increase of viability at the highest concentration between 0.1 and 1 µg/ml. We conclude that irradiation promoted a site-specific degradation of collagen. The potentially resulting peptides induce negative or positive regulations of chondrocyte growth. Taken together, these results suggest that ionizing radiation causes a degradation of cartilage proteins, leading to a functional unbalance of cartilage homeostasis after exposure, contributing to cartilage dysfunction.

Novel time-synchronized immune-guided partial tumor irradiation: Proof of principle trial.

BACKGROUND AND PURPOSE: Radiotherapy for bulky tumors often results in palliation with suboptimal outcomes. The prognosis is worsened by immunosuppression caused by radio-chemotherapy, negatively impacting on survival. Novel Partial Tumor Irradiation (PTI) was designed to spare the Peritumoral Immune Microenvironment (PIM) and to be delivered synchronously with immune activity peaks, thus enhancing both local and distant tumor control through immunostimulation. MATERIALS AND METHODS: Present proof-of-principle trial enrolled 26 patients with bulky tumors, comparing outcomes between treatments administered at immune activity peaks versus troughs. The primary endpoint was local-bystander and distal-abscopal response-rate. Secondary endpoints included overall-, progression-free-, cancer-specific survival, neoadjuvant and immunomodulatory potential. RESULTS: All measured outcomes were significantly influenced by treatment-timing. The bystander and abscopal response rates were 77% and 41%, respectively. PTI significantly upregulated pro-inflammatory and cell-death-inducing pathways improving the efficacy of radiotherapy by highly complex tumors. CONCLUSIONS: This study highlights the profound impact PTI can have on a highly palliative patient cohort previously deemed beyond therapeutic hope. With 41 % of these patients still alive after a median follow-up of 50 months, PTI offers a potential lifeline for those facing advanced, treatment-resistant cancers. This approach generated also distant immunogenic anti-tumor responses, offering a promising new avenue for the treatment of advanced cancers.

Preclinical studies of BB-1701, a HER2-targeting eribulin-containing ADC with potent bystander effect and ICD activity.

BACKGROUND: Several HER2-targeting antibody-drug conjugates (ADC) have gained market approval for the treatment of HER2-expressing metastasis. Promising responses have been reported with the new generation of ADCs in patients who do not respond well to other HER2-targeting therapeutics. However, these ADCs still face challenges of resistance and/or severe adverse effects associated with their particular payload toxins. Eribulin, a therapeutic agent for the treatment of metastatic breast cancer and liposarcoma, is a new choice of ADC payload with a distinct mechanism of action and safety profile. METHODS: We've generated a novel HER2-tageting eribulin-containing ADC, BB-1701. The potency of BB-1701 was tested in vitro and in vivo against cancer cells where HER2-expressing levels vary in a large range. Bystander killing effect and toxin-induced immunogenic cell death (ICD) of BB-1701 were also tested. RESULTS: In comparison with HER2-targeting ADCs with DM1 and Dxd payload, eribulin-containing ADC demonstrated higher in vitro cytotoxicity in HER2-low cancer cell lines. BB-1701 also effectively suppressed tumors in models resistant to DM1 or Dxd containing ADCs. Mode of action studies showed that BB-1701 had a significant bystander effect on HER2-null cells adjacent to HER2-high cells. In addition, BB-1701 treatment induced ICD. Repeated doses of BB-1701 in nonhuman primates showed favorable pharmacokinetics and safety profiles at the intended clinical dosage, route of administration, and schedule. CONCLUSIONS: The preclinical data support the test of BB-1701 in patients with various HER2-expressing cancers, including those resistant to other HER2-targeting ADCs. A phase I clinical trial of BB-1701 (NCT04257110) in patients is currently underway.

Efficient Induction of Apoptosis in Lung Cancer Cells Using Bismuth Sulfide Nanoparticles.

Background: The use of nanomaterial-based radiosensitizers to improve the therapeutic ratio has gained attraction in radiotherapy. Increased radiotoxicity applied to the tumor region may result in adverse impact on the unexposed normal cells to the radiation, a phenomenon known as radiation-induced bystander effect (RIBE). Objectives: This study aimed to investigate the effect of Bi2S3@BSA nanoparticles (NPs) as radiosensitizers on the enhancement of bystander response in non-irradiated cells. Materials and Methods: Lung carcinoma epithelial cells were exposed to 6 MV x-ray photons at different doses of 2 and 8 Gy, with and without Bi2S3@BSA NPs. The irradiated-cell's conditioned medium (ICCM) was collected and incubated with MCR-5 human fetal lung fibroblasts. Results: This study showed that ICCM collected from 2-Gy-irradiated A549 cells in the presence of Bi2S3@BSA NPs reduced the cell viability of MCR-5 bystander cells more than ICCM collected from irradiated cells without NPs (P<0.05), whereas such a difference was not observed after 8-Gy radiation. The mRNA expression of the BAX and XPA genes, as well as the cell death rate in MCR-5 bystander cells, revealed that the Bi2S3@BSA NPs significantly improved bystander response at 2-Gy (P<0.05), but the efficacy was not statistically significant after 8-Gy Irradiation. Conclusion: The results indicated that the presence of NPs did not affect bystander response enhancement at higher concentrations. These findings highlighted the potential use of radiation-enhancing agents and their benefits in radiotherapy techniques with high doses per fraction.

IL-6 knockdown in a model of the human bone marrow, abrogates DNA damage induction in bystander cells post-chemotherapy induced cytokine release syndrome.

Following infection or exposure to therapeutic agents, an aggressive immune response may result, termed cytokine storm (CS) or cytokine release syndrome. Here the innate immune system becomes uncontrolled, leading to serious consequences including possible death. Patients surviving CS are at greater risk for de novo tumorigenesis, but it is unclear if any specific cytokines are directly responsible for this outcome. De novo tumorigenesis has been observed in donated cells exposed to CS following haematopoietic stem cell transplant (HSCT). Modelling HSCT, we firstly demonstrated the release of CS levels from the HS-5 human bone marrow stromal cell line, post-exposure to chemotherapy. We then exposed the TK6 lymphoblast cell line to healthy and storm doses of IL-6 and measured increased genotoxicity via the micronucleus assay. During HSCT, haematopoietic cells are exposed to a complex mix of cytokines, so to determine if IL-6 was integral in a chemotherapy-induced bystander effect, we attempted to inhibit IL-6 from HS-5 cells using resatorvid or siRNA, treated with chlorambucil or mitoxantrone, and then co-cultured with bystander TK6 cells. Whilst resatorvid did not reduce IL-6 and did not reduce micronuclei in the bystander TK6 cells, siRNA inhibition reduced IL-6 to healthy in vivo levels, and micronuclei aligned with untreated controls. Our data suggests that exposure to high IL-6 (in the absence of inflammatory cells) has potential to induce genetic damage and may contribute to de novo tumorigenesis post-CS. We suggest that for individuals with a pro-inflammatory profile, anti-IL-6 therapy may be an appropriate intervention to prevent complications post-CS.

Non-targeted effects of radiation therapy for glioblastoma.

Radiotherapy is recommended for the treatment of brain tumors such as glioblastoma (GBM) and brain metastases. Various curative and palliative scenarios suggest improved local-regional control. Although the underlying mechanisms are not yet clear, additional therapeutic effects have been described, including proximity and abscopal reactions at the treatment site. Clinical and preclinical data suggest that the immune system plays an essential role in regulating the non-targeted effects of radiotherapy for GBM. This article reviews current biological mechanisms for regulating the non-targeted effects caused by external and internal radiotherapy, and how they might be applied in a clinical context. Optimization of therapeutic regimens requires assessment of the complexity of the host immune system on the activity of immunosuppressive or immunostimulatory cells, such as glioma-associated macrophages and microglia. This article also discusses recent preclinical models adapted to post-radiotherapy responses. This narrative review explores and discusses the current status of immune responses both locally via the "bystander effect" and remotely via the "abscopal effect". Preclinical and clinical observations demonstrate that unirradiated cells, near or far from the irradiation site, can control the tumor response. Nevertheless, previous studies do not address the problem in its global context, and present gaps regarding the link between the role of the immune system in the control of non-targeted effects for different types of radiotherapy and different fractionation schemes applied to GBM. This narrative synthesis of the scientific literature should help to update and critique available preclinical and medical knowledge. Indirectly, it will help formulate new research projects based on the synthesis and interpretation of results from a non-systematic selection of published studies.

Antibody drug conjugates: Design implications for clinicians.

OBJECTIVE: There are currently 11 antibody-drug conjugates (ADC) that are FDA approved for use in oncologic disease states, with many more in the pipeline. The authors aim to review the pharmacokinetic profiles of the components of ADCs to engage pharmacist practitioners in practical considerations in the care of patients. This article provides an overview on the use of ADCs in the setting of organ dysfunction, drug-drug interactions, and management of on- and off-target adverse effects. DATA SOURCES: A systematic search of the literature on ADCs through September 2023 was conducted. Clinical trials as well as articles on ADC design and functional components, adverse effects, and pharmacokinetics were reviewed. Reviewed literature included prescribing information as well as tertiary sources and primary literature. DATA SUMMARY: A total of 11 ADCs were reviewed for the purpose of this article. A description of the mechanism of action and structure of ADCs is outlined, and a table containing description of each currently FDA-approved ADC is included. Various mechanisms of ADC toxicity are reviewed, including how ADC structure may be implicated. CONCLUSION: It is imperative that pharmacist clinicians understand the design and function of each component of an ADC to continue to assess new approvals for use in oncology patients. Understanding the design of the ADC can help a pharmacy practitioner compare and contrast adverse effect profiles to support their multidisciplinary teams and to engage patients in education and management of their care.

Diversity of Intercellular Communication Modes: A Cancer Biology Perspective.

From the moment a cell is on the path to malignant transformation, its interaction with other cells from the microenvironment becomes altered. The flow of molecular information is at the heart of the cellular and systemic fate in tumors, and various processes participate in conveying key molecular information from or to certain cancer cells. For instance, the loss of tight junction molecules is part of the signal sent to cancer cells so that they are no longer bound to the primary tumors and are thus free to travel and metastasize. Upon the targeting of a single cell by a therapeutic drug, gap junctions are able to communicate death information to by-standing cells. The discovery of the importance of novel modes of cell-cell communication such as different types of extracellular vesicles or tunneling nanotubes is changing the way scientists look at these processes. However, are they all actively involved in different contexts at the same time or are they recruited to fulfill specific tasks? What does the multiplicity of modes mean for the overall progression of the disease? Here, we extend an open invitation to think about the overall significance of these questions, rather than engage in an elusive attempt at a systematic repertory of the mechanisms at play.

Radiation-induced bystander effect on the brain after fractionated spinal cord irradiation of aging rats.

We investigated the influence of the so-called bystander effect on metabolic and histopathological changes in the rat brain after fractionated spinal cord irradiation. The study was initiated with adult Wistar male rats (n = 20) at the age of 9 months. The group designated to irradiation (n = 10) and the age-matched control animals (n = 10) were subjected to an initial measurement using in vivo proton magnetic resonance spectroscopy (1H MRS) and magnetic resonance imaging (MRI). After allowing the animals to survive until 12 months, they received fractionated spinal cord irradiation with a total dose of 24 Gy administered in 3 fractions (8 Gy per fraction) once a week on the same day for 3 consecutive weeks. 1H MRS and MRI of brain metabolites were performed in the hippocampus, corpus striatum, and olfactory bulb (OB) before irradiation (9-month-old rats) and subsequently 48 h (12-month-old) and 2 months (14-month-old) after the completion of irradiation. After the animals were sacrificed at the age of 14 months, brain tissue changes were investigated in two neurogenic regions: the hippocampal dentate gyrus (DG) and the rostral migratory stream (RMS). By comparing the group of 9-month-old rats and individuals measured 48 h (at the age of 12 months) after irradiation, we found a significant decrease in the ratio of total N-acetyl aspartate to total creatine (tNAA/tCr) and gamma-aminobutyric acid to tCr (GABA/tCr) in OB and hippocampus. A significant increase in myoinositol to tCr (mIns/tCr) in the OB persisted up to 14 months of age. Proton nuclear magnetic resonance (1H NMR)-based plasma metabolomics showed a significant increase in keto acids and decreased tyrosine and tricarboxylic cycle enzymes. Morphometric analysis of neurogenic regions of 14-month-old rats showed well-preserved stem cells, neuroblasts, and increased neurodegeneration. The radiation-induced bystander effect more significantly affected metabolite concentration than the distribution of selected cell types.

ATR signaling controls the bystander responses of human chondrosarcoma cells by promoting RAD51-dependent DNA repair.

PURPOSE: Radiation-induced bystander effect (RIBE) frequently is seen as DNA damage in unirradiated bystander cells, but the repair processes initiated in response to that DNA damage are not well understood. RIBE-mediated formation of micronuclei (MN), a biomarker of persistent DNA damage, was previously observed in bystander normal fibroblast (AG01522) cells, but not in bystander human chondrosarcoma (HTB94) cells. The molecular mechanisms causing this disparity are not clear. Herein, we investigate the role of DNA repair in the bystander responses of the two cell lines. METHODS: Cells were irradiated with X-rays and immediately co-cultured with un-irradiated cells using a trans-well insert system in which they share the same medium. The activation of DNA damage response (DDR) proteins was detected by immunofluorescence staining or Western blotting. MN formation was examined by the cytokinesis-block MN assay, which is a robust method to detect persistent DNA damage. RESULTS: Immunofluorescent foci of γH2AX and 53BP1, biomarkers of DNA damage and repair, revealed a greater capacity for DNA repair in HTB94 cells than in AG01522 cells in both irradiated and bystander populations. Autophosphorylation of ATR at the threonine 1989 site was expressed at a greater level in HTB94 cells compared to AG01522 cells at the baseline and in response to hydroxyurea treatment or exposure to 1 Gy of X-rays. An inhibitor of ATR, but not of ATM, promoted MN formation in bystander HTB94 cells. In contrast, no effect of either inhibitor was observed in bystander AG01522 cells, indicating that ATR signaling might be a pivotal pathway to preventing the MN formation in bystander HTB94 cells. Supporting this idea, we found an ATR-dependent increase in the fractions of bystander HTB94 cells with pRPA2 S33 and RAD51 foci. A blocker of RAD51 facilitated MN formation in bystander HTB94 cells. CONCLUSION: Our results indicate that HTB94 cells were likely more efficient in DNA repair than AG01522 cells, specifically via ATR signaling, which inhibited the bystander signal-induced MN formation. This study highlights the significance of DNA repair efficiency in bystander cell responses.

TCTP regulates genotoxic stress and tumorigenicity via intercellular vesicular signaling.

Oncogenic intercellular signaling is regulated by extracellular vesicles (EVs), but the underlying mechanisms remain mostly unclear. Since TCTP (translationally controlled tumor protein) is an EV component, we investigated whether it has a role in genotoxic stress signaling and malignant transformation. By generating a Tctp-inducible knockout mouse model (Tctp-/f-), we report that Tctp is required for genotoxic stress-induced apoptosis signaling via small EVs (sEVs). Human breast cancer cells knocked-down for TCTP show impaired spontaneous EV secretion, thereby reducing sEV-dependent malignant growth. Since Trp53-/- mice are prone to tumor formation, we derived tumor cells from Trp53-/-;Tctp-/f- double mutant mice and describe a drastic decrease in tumori-genicity with concomitant decrease in sEV secretion and content. Remarkably, Trp53-/-;Tctp-/f- mice show highly prolonged survival. Treatment of Trp53-/- mice with sertraline, which inhibits TCTP function, increases their survival. Mechanistically, TCTP binds DDX3, recruiting RNAs, including miRNAs, to sEVs. Our findings establish TCTP as an essential protagonist in the regulation of sEV-signaling in the context of apoptosis and tumorigenicity.

An ethical advantage of autistic employees in the workplace.

Differences between autistic and nonautistic people are often framed as deficits. This research considers whether some of these differences might actually be strengths. In particular, autistic people tend to be less sensitive to their social environment than nonautistic people who are easily influenced by the judgments, opinions, beliefs and actions of others. Because autistic people are less susceptible to social influence, as employees they are more likely to take action when they witness an operational inefficiency or an ethical problem in the organization. By reporting problems, autistic employees may contribute to the introduction of innovations and improvements in organizational processes and effectiveness that result in superior performance. This paper considers whether and the extent to which these differences between autistic and nonautistic employees are moderated by "moral disengagement," a set of interrelated cognitive mechanisms that allow people to make unethical decisions by deactivating moral self-regulatory processes. While previous research has shown that moral disengagement is related to unethical decisions, there is no research on whether and the extent to which autistic people are vulnerable to moral disengagement. Thirty-three autistic employees and 34 nonautistic employees completed an on-line survey to determine whether differences between autistic and nonautistic employees with regards to (1) likelihood they would voice concerns about organizational dysfunctions, and (2) degree to which they were influenced by the presence of others when deciding to intervene, are moderated by individual differences in moral disengagement. As predicted, autistic participants scored lower on moral disengagement than nonautistic participants. In terms of the moderating effects of moral disengagement, the results are mixed. Although moral disengagement reduced intervention likelihood, there was not a difference between autistic and nonautistic employees in the degree to which intervention likelihood was changed by an individual's level of moral disengagement. However, there was a difference between autistic and nonautistic employees in the extent to which acknowledging the influence of others was affected by moral disengagement. These findings suggest that autistic adults are not just more likely to intervene when they witness dysfunction or misconduct in an organizational context; they are also less likely to engage in unethical behavior in general due to lower levels of moral disengagement. The reduced susceptibility to the bystander effect evidenced by autistic adults in the workplace may be accounted for, in part, by their lower levels of moral disengagement compared with nonautistic adults.

Ultra weak photon emission-a brief review.

Cells emit light at ultra-low intensities: photons which are produced as by-products of cellular metabolism, distinct from other light emission processes such as delayed luminescence, bioluminescence, and chemiluminescence. The phenomenon is known by a large range of names, including, but not limited to, biophotons, biological autoluminescence, metabolic photon emission and ultraweak photon emission (UPE), the latter of which shall be used for the purposes of this review. It is worth noting that the photons when produced are neither 'weak' nor specifically biological in characteristics. Research of UPE has a long yet tattered past, historically hamstrung by a lack of technology sensitive enough to detect it. Today, as technology progresses rapidly, it is becoming easier to detect and image these photons, as well as to describe their function. In this brief review we will examine the history of UPE research, their proposed mechanism, possible biological role, the detection of the phenomenon, and the potential medical applications.

Cell Death, by Any Other Name .

Studies trying to understand cell death, this ultimate biological process, can be traced back to a century ago. Yet, unlike many other fashionable research interests, research on cell death is more alive than ever. New modes of cell death are discovered in specific contexts, as are new molecular pathways. But what is "cell death", really? This question has not found a definitive answer yet. Nevertheless, part of the answer is irreversibility, whereby cells can no longer recover from stress or injury. Here, we identify the most distinctive features of different modes of cell death, focusing on the executive final stages. In addition to the final stages, these modes can differ in their triggering stimulus, thus referring to the initial stages. Within this framework, we use a few illustrative examples to examine how intercellular communication factors in the demise of cells. First, we discuss the interplay between cell-cell communication and cell death during a few steps in the early development of multicellular organisms. Next, we will discuss this interplay in a fully developed and functional tissue, the gut, which is among the most rapidly renewing tissues in the body and, therefore, makes extensive use of cell death. Furthermore, we will discuss how the balance between cell death and communication is modified during a pathological condition, i.e., colon tumorigenesis, and how it could shed light on resistance to cancer therapy. Finally, we briefly review data on the role of cell-cell communication modes in the propagation of cell death signals and how this has been considered as a potential therapeutic approach. Far from vainly trying to provide a comprehensive review, we launch an invitation to ponder over the significance of cell death diversity and how it provides multiple opportunities for the contribution of various modes of intercellular communication.

Adenine base editor-based correction of the cardiac pathogenic Lmna c.1621C > T mutation in murine hearts.

Base editors are emerging as powerful tools to correct single-nucleotide variants and treat genetic diseases. In particular, the adenine base editors (ABEs) exhibit robust and accurate adenine-to-guanidine editing capacity and have entered the clinical stage for cardiovascular therapy. Despite the tremendous progress using ABEs to treat heart diseases, a standard technical route toward successful ABE-based therapy remains to be fully established. In this study, we harnessed adeno-associated virus (AAV) and a mouse model carrying the cardiomyopathy-causing Lmna c.1621C > T mutation to demonstrate key steps and concerns in designing a cardiac ABE experiment in vivo. We found DeepABE as a reliable deep-learning-based model to predict ABE editing outcomes in the heart. Screening of sgRNAs for a Cas9 mutant with relieved protospacer adjacent motif (PAM) allowed the reduction of bystander editing. The ABE editing efficiency can be significantly enhanced by modifying the TadA and Cas9 variants, which are core components of ABEs. The ABE systems can be delivered into the heart via either dual AAV or all-in-one AAV vectors. Together, this study showcased crucial technical considerations in designing an ABE system for the heart and pointed out major challenges in further improvement of this new technology for gene therapy.

Sustained and Localized Drug Depot Release Using Radiation-Activated Scintillating Nanoparticles.

Clinical treatment of cancer commonly incorporates X-ray radiation therapy (XRT), and developing spatially precise radiation-activatable drug delivery strategies may improve XRT efficacy while limiting off-target toxicities associated with systemically administered drugs. Nevertheless, achieving this has been challenging thus far because strategies typically rely on radical species with short lifespans, and the inherent nature of hypoxic and acidic tumor microenvironments may encourage spatially heterogeneous effects. It is hypothesized that the challenge could be bypassed by using scintillating nanoparticles that emit light upon X-ray absorption, locally forming therapeutic drug depots in tumor tissues. Thus a nanoparticle platform (Scintillating nanoparticle Drug Depot; SciDD) that enables the local release of cytotoxic payloads only after activation by XRT is developed, thereby limiting off-target toxicity. As a proof-of-principle, SciDD is used to deliver a microtubule-destabilizing payload MMAE (monomethyl auristatin E). With as little as a 2 Gy local irradiation to tumors, MMAE payloads are released effectively to kill tumor cells. XRT-mediated drug release is demonstrated in multiple mouse cancer models and showed efficacy over XRT alone (p < 0.0001). This work shows that SciDD can act as a local drug depot with spatiotemporally controlled release of cancer therapeutics.

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

OBJECTIVES: Head and neck tumor patients may develop post-radiotherapy diseases after radiotherapy treatment. And radiotherapy can elicit radiation-induced bystander effect, wherein extracellular vesicles (EVs) play a crucial role. For normal parts of the body that have not been directly irradiated, the effect of EVs on them needs to be further explored. This study aims to investigate the functions of plasma-derived EVs in regulating normal osteoblasts during radiation-induced bystander effects. METHODS AND MATERIALS: Rat plasma-derived EVs were isolated and identified firstly, followed by an evaluation of their intracellular biological effects on normal osteoblasts in vitro. Transcriptome sequencing analysis and confirmations were performed to identify potential mechanisms. RESULTS: Irradiated plasma-derived EVs were found to enhance osteoblast proliferation, migration, and cell cycle progression, concurrently suppressing the expression of osteogenesis-related genes and proteins. Furthermore, these EVs attenuated the expression of osteogenesis and oxidative stress resistance related genes, while upregulating the PI3K-AKT pathway and intracellular reactive oxygen species in osteoblasts. CONCLUSIONS: Irradiated plasma-derived EVs could alter the biological effects in osteoblasts, which is closely associated with the levels of GPX1 and the PI3K-AKT signaling pathway. This suggests that plasma-derived EVs serve as a crucial factor contributing to radiation-induced bystander effect in osteoblasts.

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

BACKGROUND: The global need for wireless technologies is growing rapidly. So, we have been exposed to a new type of environmental pollution: radiofrequency radiation (RFR). Recent studies have shown that RFR can cause not only direct effects but also indirect or non-targeted effects such as the bystander effect (BE). In this study, we investigated the BE induced by RFR in the present of gold nanoparticles (GNP). Moreover, we studied the expression of cyclooxygenase-2 (COX-2). METHODS: Non-toxic dose of 15-nm GNP was used to treat the Chinese Hamster Ovary (CHO) cells. After 48 h of incubation, cells were exposed to 900 MHz GSM RFR for 24 h. Then we collected the cell culture medium of these cells (conditioned culture medium, CCM) and transferred it to new cells (bystander cells). Cell deaths, DNA breaks, oxidative stress and COX-2 expression were analyzed in all groups. RESULTS: The results showed that RFR increased metabolic death in cells treated with GNP. Inversely, the colony formation ability was reduced in bystander cells and RFR exposed cells either in the presence or absence of GNP. Also, the level of reactive oxygen species (ROS) in GNP treated cells showed a significant reduction compared to those of untreated cells. However, RFR-induced DNA breaks and the frequencies of micronuclei (MN) were not significantly affected by GNP. The expression of COX-2 mRNA increased in RFR GNP treated cells, but the difference was not significant. CONCLUSION: Our results for the first time indicated that RFR induce indirect effects in the presence of GNP. However, the molecular mediators of these effects differ from those in the absence of GNP. Also, to our knowledge, this is the first study to show that COX-2 is not involved in the bystander effect induced by 900 MHz RFR.