Transcriptomic response of prostate cancer cells to carbon ion and photon irradiation with focus on androgen receptor and TP53 signaling.

BACKGROUND: Radiotherapy is essential in the treatment of prostate cancer. An alternative to conventional photon radiotherapy is the application of carbon ions, which provide a superior intratumoral dose distribution and less induced damage to adjacent healthy tissue. A common characteristic of prostate cancer cells is their dependence on androgens which is exploited therapeutically by androgen deprivation therapy in the advanced prostate cancer stage. Here, we aimed to analyze the transcriptomic response of prostate cancer cells to irradiation by photons in comparison to carbon ions, focusing on DNA damage, DNA repair and androgen receptor signaling. METHODS: Prostate cancer cell lines LNCaP (functional TP53 and androgen receptor signaling) and DU145 (dysfunctional TP53 and androgen receptor signaling) were irradiated by photons or carbon ions and the subsequent DNA damage was assessed by immuno-cytofluorescence. Furthermore, the cells were treated with an androgen-receptor agonist. The effects of irradiation and androgen treatment on the gene regulation and the transcriptome were investigated by RT-qPCR and RNA sequencing, followed by bioinformatic analysis. RESULTS: Following photon or carbon ion irradiation, both LNCaP and DU145 cells showed a dose-dependent amount of visible DNA damage that decreased over time, indicating occurring DNA repair. In terms of gene regulation, mRNAs involved in the TP53-dependent DNA damage response were significantly upregulated by photons and carbon ions in LNCaP but not in DU145 cells, which generally showed low levels of gene regulation after irradiation. Both LNCaP and DU145 cells responded to photons and carbon ions by downregulation of genes involved in DNA repair and cell cycle, partially resembling the transcriptome response to the applied androgen receptor agonist. Neither photons nor carbon ions significantly affected canonical androgen receptor-dependent gene regulation. Furthermore, certain genes that were specifically regulated by either photon or carbon ion irradiation were identified. CONCLUSION: Photon and carbon ion irradiation showed a significant congruence in terms of induced signaling pathways and transcriptomic responses. These responses were strongly impacted by the TP53 status. Nevertheless, irradiation mode-dependent distinct gene regulations with undefined implication for radiotherapy outcome were revealed. Androgen receptor signaling and irradiations shared regulation of certain genes with respect to DNA-repair and cell-cycle.

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.

Anti-Inflammatory and Immunomodulatory Effects of 0.1 Sub-Terahertz Irradiation in Collagen-Induced Arthritis Mice.

The primary emphasis of photoimmunology is the impact of nonionizing radiation on the immune system. With the development of terahertz (THz) and sub-terahertz (sub-THz) technology, the biological effects of this emerging nonionizing radiation, particularly its influence on immune function, remain insufficiently explored but are progressively attracting attention. Here, we demonstrated that 0.1 sub-THz radiation can modulate the immune system and alleviate symptoms of arthritis in collagen-induced arthritis (CIA) mice through a nonthermal manner. The application of 0.1 sub-THz irradiation led to a decrease in proinflammatory factors within the joints and serum, reducing the levels of blood immune cells and the quantity of splenic CD4+ T cells. Notably, 0.1 sub-THz irradiation restored depleted Treg cells in CIA mice and re-established the Th17/Treg equilibrium. These findings suggested that sub-THz irradiation plays a crucial role in systemic immunoregulation. Further exploration of its immune modulation mechanisms revealed the anti-inflammatory properties of 0.1 sub-THz on LPS-stimulated skin keratinocytes. Through the reduction in NF-κB signaling and NLRP3 inflammasome activation, 0.1 sub-THz irradiation effectively decreased the production of inflammatory factors and immune-active substances, including IL-1ß and PGE2, in HaCaT cells. Consequently, 0.1 sub-THz irradiation mitigated the inflammatory response and contributed to the maintenance of immune tolerance in CIA mice. This research provided significant new evidence supporting the systemic impacts of 0.1 sub-THz radiation, particularly on the immune system. It also enhanced the field of photoimmunology and offered valuable insights into the potential biomedical applications of 0.1 sub-THz radiation for treating autoimmune diseases.

A Preliminary Investigation into the Effect of Low-Energy Lasers on Dental Pulp Stem Cell Proliferation and the Associated Mechanism.

BACKGROUND: Dental pulp stem cells (DPSCs) have self-renewal and multidirectional differentiation potentials. As such, DPSCs have a wide range of clinical applications. Low-level laser therapy (LLLT) has positive photobiostimulatory effects on cell proliferation, angiogenesis, osteogenic differentiation, bone regeneration, and fracture healing. However, there have been few studies on the effect of low-energy lasers on DPSC proliferation. METHODS: DPSCs were obtained from dental pulp tissue. The effects of LLLT on the proliferation of DPSCs and the associated mechanisms were investigated by in vitro culture and laser irradiation. RESULTS: LLLT with energy densities of 3.5 J/cm2 and 14 J/cm2promoted the proliferation of DPSCs. Differential protein expression studies suggested the stimulation of DPSC proliferation by LLLT involved the PI3K-Akt and Rap1 signaling pathways, as well as the apoptosis-related pathway. CONCLUSION: This preliminary study demonstrated that low-energy lasers have a pro-proliferative effect on DPSCs, and identified possible associated mechanisms. Our findings provide a theoretical basis for the clinical application of DPSCs and suggest novel strategies for the treatment of related diseases.

Megakaryocytic IGF1 coordinates activation and ferroptosis to safeguard hematopoietic stem cell regeneration after radiation injury.

BACKGROUND: Hematopoietic stem cell (HSC) regeneration underlies hematopoietic recovery from myelosuppression, which is a life-threatening side effect of cytotoxicity. HSC niche is profoundly disrupted after myelosuppressive injury, while if and how the niche is reshaped and regulates HSC regeneration are poorly understood. METHODS: A mouse model of radiation injury-induced myelosuppression was built by exposing mice to a sublethal dose of ionizing radiation. The dynamic changes in the number, distribution and functionality of HSCs and megakaryocytes were determined by flow cytometry, immunofluorescence, colony assay and bone marrow transplantation, in combination with transcriptomic analysis. The communication between HSCs and megakaryocytes was determined using a coculture system and adoptive transfer. The signaling mechanism was investigated both in vivo and in vitro, and was consolidated using megakaryocyte-specific knockout mice and transgenic mice. RESULTS: Megakaryocytes become a predominant component of HSC niche and localize closer to HSCs after radiation injury. Meanwhile, transient insulin-like growth factor 1 (IGF1) hypersecretion is predominantly provoked in megakaryocytes after radiation injury, whereas HSCs regenerate paralleling megakaryocytic IGF1 hypersecretion. Mechanistically, HSCs are particularly susceptible to megakaryocytic IGF1 hypersecretion, and mTOR downstream of IGF1 signaling not only promotes activation including proliferation and mitochondrial oxidative metabolism of HSCs, but also inhibits ferritinophagy to restrict HSC ferroptosis. Consequently, the delicate coordination between proliferation, mitochondrial oxidative metabolism and ferroptosis ensures functional HSC expansion after radiation injury. Importantly, punctual IGF1 administration simultaneously promotes HSC regeneration and hematopoietic recovery after radiation injury, representing a superior therapeutic approach for myelosuppression. CONCLUSIONS: Our study identifies megakaryocytes as a last line of defense against myelosuppressive injury and megakaryocytic IGF1 as a novel niche signal safeguarding HSC regeneration.

Ionizing radiation induces neurotoxicity in Xenopus laevis embryos through neuroactive ligand-receptor interaction pathway.

Ionizing radiation (IR) poses a significant threat to both the natural environment and biological health. Exposure to specific doses of ionizing radiation early in an organism's development can lead to developmental toxicity, particularly neurotoxicity. Through experimentation with Xenopus laevis (X. laevis), we examined the effects of radiation on early developmental stage. Our findings revealed that radiation led to developmental abnormalities and mortality in X. laevis embryos in a dose-dependent manner, disrupting redox homeostasis and inducing cell apoptosis. Additionally, radiation caused neurotoxic effects, resulting in abnormal behavior and neuron damage in the embryos. Further investigation into the underlying mechanisms of radiation-induced neurotoxicity indicated the potential involvement of the neuroactive ligand-receptor interaction pathway, which was supported by RNA-Seq analysis. Validation of gene expression associated with this pathway and analysis of neurotransmitter levels confirmed our hypothesis. In addition, we further validated the important role of this signaling pathway in radiation-induced neurotoxicity through edaravone rescue experiments. This research establishes a valuable model for radiation damage studying and provides some insight into radiation-induced neurotoxicity mechanisms.

SCF/C-kit drives spermatogenesis disorder induced by abscopal effects of cranial irradiation in mice.

Cranial radiotherapy is a major treatment for leukemia and brain tumors. Our previous study found abscopal effects of cranial irradiation could cause spermatogenesis disorder in mice. However, the exact mechanisms are not yet fully understood. In the study, adult male C57BL/6 mice were administrated with 20 Gy X-ray cranial irradiation (5 Gy per day for 4 days consecutively) and sacrificed at 1, 2 and 4 weeks. Tandem Mass Tag (TMT) quantitative proteomics of testis was combined with bioinformatics analysis to identify key molecules and signal pathways related to spermatogenesis at 4 weeks after cranial irradiation. GO analysis showed that spermatogenesis was closely related to oxidative stress and inflammation. Severe oxidative stress occurred in testis, serum and brain, while serious inflammation also occurred in testis and serum. Additionally, the sex hormones related to hypothalamic-pituitary-gonadal (HPG) axis were disrupted. PI3K/Akt pathway was activated in testis, which upstream molecule SCF/C-Kit was significantly elevated. Furthermore, the proliferation and differentiation ability of spermatogonial stem cells (SSCs) were altered. These findings suggest that cranial irradiation can cause spermatogenesis disorder through brain-blood-testicular cascade oxidative stress, inflammation and the secretory dysfunction of HPG axis, and SCF/C-kit drive this process through activating PI3K/Akt pathway.

Predictive DNA damage signaling for low­dose ionizing radiation.

Numerous studies have attempted to develop biological markers for the response to radiation for broad and straightforward application in the field of radiation. Based on a public database, the present study selected several molecules involved in the DNA damage repair response, cell cycle regulation and cytokine signaling as promising candidates for low­dose radiation­sensitive markers. The HuT 78 and IM­9 cell lines were irradiated in a concentration­dependent manner, and the expression of these molecules was analyzed using western blot analysis. Notably, the activation of ataxia telangiectasia mutated (ATM), checkpoint kinase 2 (CHK2), p53 and H2A histone family member X (H2AX) significantly increased in a concentration­dependent manner, which was also observed in human peripheral blood mononuclear cells. To determine the radioprotective effects of cinobufagin, as an ATM and CHK2 activator, an in vivo model was employed using sub­lethal and lethal doses in irradiated mice. Treatment with cinobufagin increased the number of bone marrow cells in sub­lethal irradiated mice, and slightly elongated the survival of lethally irradiated mice, although the difference was not statistically significant. Therefore, KU60019, BML­277, pifithrin­α, and nutlin­3a were evaluated for their ability to modulate radiation­induced cell death. The use of BML­277 led to a decrease in radiation­induced p­CHK2 and γH2AX levels and mitigated radiation­induced apoptosis. On the whole, the present study provides a novel approach for developing drug candidates based on the profiling of biological radiation­sensitive markers. These markers hold promise for predicting radiation exposure and assessing the associated human risk.

Plant hormones and phenolic acids response to UV-B stress in Rhododendron chrysanthum pall.

Our study aims to identify the mechanisms involved in regulating the response of Rhodoendron Chrysanthum Pall. (R. chrysanthum) leaves to UV-B exposure; phosphorylated proteomics and metabolomics for phenolic acids and plant hormones were integrated in this study. The results showed that UV-B stress resulted in the accumulation of salicylic acid and the decrease of auxin, jasmonic acid, abscisic acid, cytokinin and gibberellin in R. chrysanthum. The phosphorylated proteins that changed in plant hormone signal transduction pathway and phenolic acid biosynthesis pathway were screened by comprehensive metabonomics and phosphorylated proteomics. In order to construct the regulatory network of R. chrysanthum leaves under UV-B stress, the relationship between plant hormones and phenolic acid compounds was analyzed. It provides a rationale for elucidating the molecular mechanisms of radiation tolerance in plants.

BIBR1532 combined with radiotherapy induces ferroptosis in NSCLC cells and activates cGAS-STING pathway to promote anti-tumor immunity.

BACKGROUND: Telomerase, by safeguarding damaged telomeres and bolstering DNA damage repair, has the capacity to heighten the radioresistance of tumour cells. Thus, in turn, can compromise the efficacy of radiotherapy (RT) and radioimmunotherapy. Our previous studies have revealed that the highly selective telomerase inhibitor, BIBR1532, possesses the potential to enhance the radiosensitivity of Non-small cell lung cancer (NSCLC). In this study, we delve further into the impact of BIBR1532 on the immune activation induced by RT and elucidate the underlying mechanisms. METHODS: Biological information analyses, immunofluorescence assays, western blot assays, flow cytometry analysis were conducted to elucidate the functions of the combination of BIBR1532 with radiotherapy in NSCLC. Intracellular levels of lipid peroxides, glutathione, malondialdehyde, and Fe2+ were measured as indicators of ferroptosis status. Both in vitro and in vivo studies were conducted to examine the antitumor effects. RESULTS: Our findings indicate that the confluence of BIBR1532 with RT significantly augments the activation of the cGAS-STING pathway in both in vivo and in vitro settings, thereby fostering an effective anti-tumoral immune response. The effects can be ascribed to two key processes. Firstly, ionizing radiation, in precipitating DNA double-strand breaks (DSBs), prompts the release of tumour-derived double-stranded DNA (dsDNA) into the cytoplasm. Subsequently, BIBR1532 amplifies the activation of antigen-presenting cells by dsDNA post-RT and instigates the cGAS-STING pathway. Secondly, BIBR1532 enhances the ferroptosis response in NSCLC following RT, thereby promoting unrestrained lipid peroxidation and elevated levels of reactive oxygen species (ROS) within tumour cells. This ultimately leads to mitochondrial stress and the release of endogenous mitochondrial DNA (mtDNA) into the cytoplasm, thus facilitating the activation of the STING pathway and the induction of a type I interferon (IFN)-linked adaptive immune response. CONCLUSION: This study underscores the potential of BIBR1532 as an efficacious and safe radiosensitizer and radioimmunotherapy synergist, providing robust preclinical research evidence for the treatment of NSCLC.

Regulation of cellular responses to X-ray irradiation through the activation of lysophosphatidic acid (LPA) receptor-3 (LPA3) and LPA2 in osteosarcoma cells.

Lysophosphatidic acid (LPA) binds to its specific G protein-coupled LPA receptors (LPA1 to LPA6), resulting in the activation of various cellular functions. LPA receptor-mediated signaling facilitates tumor progression in human malignancies. In the present study, we investigated whether LPA receptor-mediated signaling contributes to cellular responses to X-ray irradiation in osteosarcoma MG-63 cells. After X-ray irradiation (2, 4 and 8 Gy), LPAR2 and LPAR3 expression levels in MG-63 cells were significantly elevated in a dose-dependent manner, but no change of LPAR1 expression level was observed. The cell growth activities of MG-63 cells irradiated with X-rays (2, 4 and 8 Gy) were reduced by LPA. Conversely, LPA3 agonist (2 S)-OMPT enhanced the cell growth activities of X-ray irradiated MG-63 cells. The cell movement of MG-63 cells exposed to X-ray irradiation (8 Gy) was inhibited by (2 S)OMPT. In cell survival assay, (2 S)-OMPT suppressed the cell survival to cisplatin (CDDP) of MG-63 cells irradiated with X-rays (8 Gy). The cell survival to CDDP of X-ray irradiated cells was elevated by LPA3 knockdown. Moreover, we evaluated the effects of LPA2 on the cell survival to CDDP of MG-63 cells exposed to X-ray irradiation (8 Gy). The cell survival to CDDP of X-ray irradiated cells was increased by LPA2 agonist GRI-977143 and reduced by LPA2 knockdown. These results suggest that LPA receptor-signaling participates in the modulation of cellular functions induced by X-ray irradiation in osteosarcoma cells.

Blue light induced ferroptosis via STAT3/GPX4/SLC7A11/FTH1 in conjunctiva epithelium in vivo and in vitro.

The prevalence of Light-emitting diodes (LEDs) has exposed us to an excessive amount of blue light (BL) which causes various ophthalmic diseases. Previous studies have shown that conjunctiva is vulnerable to BL. In this study, we aimed to investigate the underlying mechanism of BL-induced injury in conjunctiva. We placed C57BL/6 mice and human conjunctival epithelial cell lines (HCECs) under BL (440 nm ± 15 nm, 0.2 mW/cm2) to establish a BL injury model in vivo and in vitro. Immunohistochemistry and MDA assay were used to identify lipid peroxidation (LPO) in vivo. HE staining was applied to detect morphological damage of conjunctival epithelium. DCFH-DA, C11-BODIPY 581/591, Calcein-AM, and FeRhoNox™-1 probes were performed to identify ferroptosis levels in vitro. Real-time qPCR and Western blotting techniques were employed to uncover signaling pathways of blue light-induced ferroptosis. Our findings demonstrated that BL affected tear film instability and induced conjunctival epithelium injury in vivo. Ferrostatin-1 significantly alleviated blue light-induced ferroptosis in vivo and in vitro. BL downregulates the levels of solute carrier family 7 member 11 (SLC7A11), Ferritin heavy chain (FTH1), and glutathione peroxidase (GPX4) by inhibiting the activation and translocation of the Signal transducer and activator of transcription 3 (STAT3) from inducing Fe2+ burst, ROS and LPO accumulation, ultimately resulting in ferroptosis. This study will offer new insight into BL-induced conjunctival injury and LED-induced dry eye.

Epigenetic regulation of TGF-ß pathway and its role in radiation response.

PURPOSE: Transforming growth factor (TGF-ß) plays a dual role in tumor progression as well as a pivotal role in radiation response. TGF-ß-related epigenetic regulations, including DNA methylation, histone modifications (including methylation, acetylation, phosphorylation, ubiquitination), chromatin remodeling and non-coding RNA regulation, have been found to affect the occurrence and development of tumors as well as their radiation response in multiple dimensions. Due to the significance of radiotherapy in tumor treatment and the essential roles of TGF-ß signaling in radiation response, it is important to better understand the role of epigenetic regulation mechanisms mediated by TGF-ß signaling pathways in radiation-induced targeted and non-targeted effects. CONCLUSIONS: By revealing the epigenetic mechanism related to TGF-ß-mediated radiation response, summarizing the existing relevant adjuvant strategies for radiotherapy based on TGF-ß signaling, and discovering potential therapeutic targets, we hope to provide a new perspective for improving clinical treatment.

UVR8-TCP4-LOX2 module regulates UV-B tolerance in Arabidopsis.

The phytohormone jasmonate (JA) coordinates stress and growth responses to increase plant survival in unfavorable environments. Although JA can enhance plant UV-B stress tolerance, the mechanisms underlying the interaction of UV-B and JA in this response remain unknown. In this study, we demonstrate that the UV RESISTANCE LOCUS 8 - TEOSINTE BRANCHED1, Cycloidea and PCF 4 - LIPOXYGENASE2 (UVR8-TCP4-LOX2) module regulates UV-B tolerance dependent on JA signaling pathway in Arabidopsis thaliana. We show that the nucleus-localized UVR8 physically interacts with TCP4 to increase the DNA-binding activity of TCP4 and upregulate the JA biosynthesis gene LOX2. Furthermore, UVR8 activates the expression of LOX2 in a TCP4-dependent manner. Our genetic analysis also provides evidence that TCP4 acts downstream of UVR8 and upstream of LOX2 to mediate plant responses to UV-B stress. Our results illustrate that the UV-B-dependent interaction of UVR8 and TCP4 serves as an important UVR8-TCP4-LOX2 module, which integrates UV-B radiation and JA signaling and represents a new UVR8 signaling mechanism in plants.

Distinguish response of low-dose radiation with different dose-rate on gene expression of human coronary artery endothelial cells: a bioinformatic study based on transcriptomic sequencing.

PURPOSE: People are exposed to low-dose radiation in medical diagnosis, occupational, or life circumstances, but the effect of low-dose radiation on human health is still controversial. The biological effects of radiation below 100 mGy are still unproven. In this study, we observed the effects of low-dose radiation (100 mGy) on gene expression in human coronary artery endothelial cells (HCAECs) and its effect on molecular signaling. MATERIALS AND METHODS: HCAECs were exposed to 100 mGy ionizing radiation at 6 mGy/h (low-dose-rate) or 288 mGy/h (high-dose-rate). After 72 h, total RNA was extracted from sham or irradiated cells for Quant-Seq 3'mRNA-Seq, and bioinformatic analyses were performed using Metascape. Gene profiling was validated using qPCR. RESULTS: Compared to the non-irradiated control group, 100 mGy of ionizing radiation at 6 mGy/h altered the expression of 194 genes involved in signaling pathways related to heart contraction, blood circulation, and cardiac myofibril assembly differentially. However, 100 mGy at 288 mGy/h altered expression of 450 genes involved in cell cycle-related signaling pathways, including cell division, nuclear division, and mitosis differentially. Additionally, gene signatures responding to low-dose radiation, including radiation dose-specific gene profiles (HIST1H2AI, RAVER1, and POTEI) and dose-rate-specific gene profiles (MYL2 for the low-dose-rate and DHRS9 and CA14 for the high-dose-rate) were also identified. CONCLUSIONS: We demonstrated that 100 mGy low-dose radiation could alter gene expression and molecular signaling pathways at the low-dose-rate and the high-dose-rate differently. Our findings provide evidence for further research on the potential impact of low-dose radiation on cardiovascular function.

Comparison of Three Antagonists of Hedgehog Pathway to Promote Skeletal Muscle Regeneration after High Dose Irradiation.

The current geopolitical context has brought the radiological nuclear risk to the forefront of concerns. High-dose localized radiation exposure leads to the development of a musculocutaneous radiation syndrome affecting the skin and subcutaneous muscles. Despite the implementation of a gold standard treatment based on an invasive surgical procedure coupled with autologous cell therapy, a muscular defect frequently persists. Targeting the modulation of the Hedgehog (Hh) signaling pathway appears to be a promising therapeutic approach. Activation of this pathway enhances cell survival and promotes proliferation after irradiation, while inhibition by Cyclopamine facilitates differentiation. In this study, we compared the effects of three antagonists of Hh, Cyclopamine (CA), Vismodegib (VDG) and Sonidegib (SDG) on differentiation. A stable cell line of murine myoblasts, C2C12, was exposed to X-ray radiation (5 Gy) and treated with CA, VDG or SDG. Analysis of proliferation, survival (apoptosis), morphology, myogenesis genes expression and proteins production were performed. According to the results, VDG does not have a significant impact on C2C12 cells. SDG increases the expression/production of differentiation markers to a similar extent as CA, while morphologically, SDG proves to be more effective than CA. To conclude, SDG can be used in the same way as CA but already has a marketing authorization with an indication against basal cell cancers, facilitating their use in vivo. This proof of concept demonstrates that SDG represents a promising alternative to CA to promotes differentiation of murine myoblasts. Future studies on isolated and cultured satellite cells and in vivo will test this proof of concept.

Radiation-induced Bystander Effects on Glioblastoma Tumor Cells via NMDA Receptor Signaling.

Proton therapy has been widely applied on treating inaccessible and inoperable tumors, such as tumors deep within the brain or close to the critical brain stem. Nevertheless, the damaging effect of radiation for central nervous system (CNS) tumors is difficult to be confined within the irradiated region and has led to decline of neurological function in especially children with congenital CNS tumors. Currently, the involvement of n-methyl-d-aspartate (NMDA) receptors or secretary cytokines and chemokines in proton-induced bystander effects remains unclear. To understand the modulatory effects of NMDA receptor inhibition on the survival and proliferation of glioblastoma-derived cells, mesenchymal-like U373 cells were applied along with U87 neural glioblastoma cells for single doses of proton radiation at different LET in the presence or absence of pretreatment with memantine and/or collimation. Under collimation, neuronal tumor cells that are not directly irradiated (i.e., bystander cells) encounter similar biological effects potentially through cell coupling and synaptic transmission. Furthermore, whether proton LET plays a role in the mediation of bystander effect awaits to be elucidated. From this study, synaptic transmission was found to play differential roles in the proliferation of U373 and U87 cells after exposure to collimated radiation. Also, radiation-induced cell proliferation at the late stage was more correlated with bystander cell survival than early manifested γH2AX foci, suggesting that proton-induced glutamatergic synapse may act as a more important contributor than proton-induced direct effect on DNA double-stranded breaks to the late-stage responses of glioblastoma cells.

Photobiomodulation at 660 nm Stimulates In Vitro Diabetic Wound Healing via the Ras/MAPK Pathway.

Diabetic foot ulcers (DFUs) are open chronic wounds that affect diabetic patients due to hyperglycaemia. DFUs are known for their poor response to treatment and frequently require amputation, which may result in premature death. The present study evaluated the effect of photobiomodulation (PBM) at 660 nm on wound healing via activation of Ras/MAPK signalling in diabetic wounded cells in vitro. This study used four human skin fibroblast cell (WS1) models, namely normal (N), wounded (W), diabetic (D), and diabetic wounded (DW). Cells were irradiated at 660 nm with 5 J/cm2. Non-irradiated cells (0 J/cm2) served as controls. Cells were incubated for 24 and 48 h post-irradiation, and the effect of PBM on cellular morphology and migration rate, viability, and proliferation was assessed. Basic fibroblast growth factor (bFGF), its phosphorylated (activated) receptor FGFR, and phosphorylated target proteins (Ras, MEK1/2 and MAPK) were determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting; nuclear translocation of p-MAPK was determined by immunofluorescence. PBM resulted in an increase in bFGF and a subsequent increase in FGFR activation. There was also an increase in downstream proteins, p-Ras, p-MEK1/2 and p-MAPK. PBM at 660 nm led to increased viability, proliferation, and migration as a result of increased bFGF and subsequent activation of the Ras/MAPK signalling pathway. Therefore, this study can conclude that PBM at 660 nm stimulates in vitro diabetic wound healing via the bFGF-activated Ras/MAPK pathway.

The ALK1­Smad1/5­ID1 pathway participates in tumour angiogenesis induced by low­dose photodynamic therapy.

Photodynamic therapy (PDT) is an effective and low­invasive tumour therapy. However, it can induce tumour angiogenesis, which is a main factor leading to tumour recurrence and metastasis. Activin receptor­like kinase­1 (ALK1) is a key factor regulating angiogenesis. However, it remains unclear whether ALK1 plays an unusual role in low­dose PDT­induced tumour angiogenesis. In the present study, human umbilical vein endothelial cells (HUVECs) co­cultured with breast cancer MDA­MB­231 cells (termed HU­231 cells) were used to construct an experimental model of tumour angiogenesis induced by low­dose PDT. The viability, and the proliferative, invasive, migratory, as well as the tube­forming ability of the HU­231 cells were evaluated following low­dose PDT. In particular, ALK1 inhibitor and and an adenovirus against ALK1 were used to further verify the role of ALK1 in low­dose PDT­induced tumour angiogenesis. Moreover, the expression of ALK1, inhibitor of DNA binding 1 (ID1), Smad 1, p­Smad1/5, AKT and PI3K were detected in order to verify the underlying mechanisms. The findings indicated that low­dose PDT enhanced the proliferative ability of the HU­231 cells and reinforced their migratory, invasive and tube formation capacity. However, these effects were reversed with the addition of an ALK1 inhibitor or by the knockdown of ALK1 using adenovirus. These results indicated that ALK1 was involved and played a critical role in tumour angiogenesis induced by low­dose PDT. Furthermore, ALK1 was found to participate in PDT­induced tumour angiogenesis by activating the Smad1/5­ID1 pathway, as opposed to the PI3K/AKT pathway. On the whole, the present study, for the first time, to the best of our knowledge, demonstrates that ALK1 is involved in PDT­induced tumour angiogenesis. The inhibition of ALK1 can suppress PDT­induced tumour angiogenesis, which can enhance the effects of PDT and may thus provide a novel treatment strategy for PDT.