Exploring the radiosensitizing potential of magnetotherapy: a pilot study in breast cancer cells

Abstract

Aim: To explore the influence of electromagnetic fields (EMFs) on the cell cycle progression of MDA-MB-231 and MCF-7 breast cancer cell lines and to evaluate the radiosensitizing effect of magnetotherapy during therapeutic co-exposure to EMFs and radiotherapy.

Material and methods: Cells were exposed to EMFs (25, 50 and 100?Hz; 8 and 10?mT). In the co-treatment, cells were first exposed to EMFs (50?Hz/10?mT) for 30?min and then to ionizing radiation (IR) (2?Gy) 4?h later. Cell cycle progression and free radical production were evaluated by flow cytometry, while radiosensitivity was explored by colony formation assay.

Results: Generalized G1-phase arrest was found in both cell lines several hours after EMF exposure. Interestingly, a marked G1-phase delay was observed at 4?h after exposure to 50?Hz/10?mT EMFs. No cell cycle perturbation was observed after repeated exposure to EMFs. IR-derived ROS production was enhanced in EMF-exposed MCF-7 cells at 24?h post-exposure. EMF-exposed cells were more radiosensitive in comparison to sham-exposed cells.

Conclusions: These results highlight the potential benefits of concomitant treatment with magnetotherapy before radiotherapy sessions to enhance the effectiveness of breast cancer therapy. Further studies are warranted to identify the subset(s) of patients who would benefit from this multimodal treatment.     

Exposure to electromagnetic field attenuates oxygen-glucose deprivation-induced microglial cell death by reducing intracellular Ca2+ and ROS

Purpose The aim of this research was to demonstrate the protective effects of electromagnetic field (EMF) exposure on the human microglial cell line, HMO6, against ischemic cell death induced by in vitro oxygen-glucose deprivation (OGD).

Materials and methods HMO6 cells were cultured for 4?h under OGD with or without exposure to EMF with different combinations of frequencies and intensities (10, 50, or 100?Hz/1?mT and 50?Hz/0.01, 0.1, or 1?mT). Cell survival, intracellular calcium and reactive oxygen species (ROS) levels were measured.

Results OGD caused significant HMO6 cell death as well as elevation of intracellular Ca²⁺ and ROS levels. Among different combinations of EMF frequencies and intensities, 50?Hz/1?mT EMF was the most potent to attenuate OGD-induced cell death and intracellular Ca²⁺ and ROS levels. A significant but less potent protective effect was also found at 10?Hz/1?mT, whereas no protective effect was found at other combinations of EMF. A xanthine oxidase inhibitor reversed OGD-induced ROS production and cell death, while NADPH oxidase and mitochondrial respiration chain complex II inhibitors did not affect cell death.

Conclusions 50?Hz/1?mT EMF protects human microglial cells from OGD-induced cell death by interfering with OGD-induced elevation of intracellular Ca²⁺ and ROS levels, and xanthine oxidase is one of the main mediators involved in OGD-induced HMO6 cell death. Non-invasive treatment of EMF radiation may be clinically useful to attenuate hypoxic-ischemic brain injury.     

NADPH oxidase-produced superoxide mediated a 50-Hz magnetic field-induced epidermal growth factor receptor clustering

Purpose: A 50-Hz magnetic field (MF) was found to induce epidermal growth factor receptor (EGFR) clustering in our previous study. The aim of this work was to investigate the molecular mechanisms that mediated MF-induced EGFR clustering.

Materials and methods: Human amniotic epithelial (FL) cells were exposed to a 50-Hz MF. Total reactive oxygen species (ROS), cytoplasmic and mitochondrial superoxide production were detected by DCFH-DA, DHE and MitoSOX, respectively. EGFR clustering was analyzed using confocal microscopy after indirect immunofluorescence staining.

Results: Results showed that exposing FL cells to MF at intensity higher than 0.2?mT for 15?min enhanced total ROS production. Additionally, enhanced total ROS and cytoplasmic superoxide production were observed after exposing cells to MF at 0.4?mT for 5, 15, or 30?min, while mitochondrial superoxide production for 15 or 30?min. Pretreatment with Nox inhibitor, DPI, effectively inhibited MF-induced cytoplasmic superoxide production and subsequent EGFR clustering while mitochondrial superoxide production was not affected.

Conclusions: Nox-produced superoxide mediated a 50-Hz magnetic field-induced EGFR clustering.     

Coupling of oxidative stress responses to tricarboxylic acid cycle and prostaglandin E2 alterations in Caenorhabditis elegans under extremely low-frequency electromagnetic field

Purpose: With all-pervasive presence of extremely low-frequency electromagnetic field (ELF-EMF) in modern life, ELF-EMF has been regarded as an essential factor which may induce changes in many organisms. The objective of the present study was to investigate the physiological responses of Caenorhabditis elegans (C. elegans) to 50?Hz, 3?mT ELF-EMF exposure.

Materials and methods: Worms were exposed to ELF-EMF from the egg stage until reaching the fourth larva (L4) stage. After exposure, expressions of the tricarboxylic acid (TCA) cycle enzymes were examined by qRT-PCR and western blot analysis. Two lipid metabolites were detected by GC-MS. Reactive oxygen species (ROS) level was detected by dichlorofluorescein staining and worm antioxidant system was investigated by enzymatic activity analysis, including detection of the superoxide dismutase and catalase (CAT) activity and the total antioxidant capacity (T-AOC).

Results: The TCA cycle enzyme, fumarase was found with decreased expression under ELF-EMF exposure. And arachidonic acid (ArA) and prostaglandin E₂(PGE₂) showed elevated concentrations, with increased expression of prostaglandin E₂ synthase (PGES-2) in ELF-EMF exposed worms. Significant elevation of ROS level was identified accompanied with the significant depression of T-AOC in response to ELF-EMF.

Conclusions: Our results suggested that exposure to 50?Hz, 3?mT ELF-EMF in C. elegans can elicit disruptions of the TCA cycle metabolism and PGE₂ formation, coupling ELF-EMF-induced oxidative stress responses. Our study probably will attract increasing attentions to the controllable application of ELF-EMF associated with health and disease.     

Oxidative and nitrative stress-related changes in human lens epithelial cells following exposure to X-rays

Purpose: There is limited understanding of the mechanistic effects of ionizing radiation (IR) exposure in cataract formation. In this study, we explored the effects of IR on reactive oxygen/nitrogen species (ROS and RNS) generation in human lens epithelial (HLE) cells as an early key event to long-term damage.

Materials and methods: HLE cell-line was exposed to X-rays at varied doses (0–5?Gy) and dose-rates. Cell lysates and supernatants were collected 20?h post-exposure and analysed for viability, cell cycling and metabolites of ROS (p, m-, o-, tyrosines, 3-chlorotyrosine (cl-tyrosine), 8-hydroxy deoxyguanosine, (8-OH-dG) and RNS (3-nitrotyrosine).

Results and conclusions: HLE cell-line exhibited a bi-phasic response in terms of cell viability, ROS and RNS profiles. At doses <0.5?Gy, ROS and RNS levels were lower than control and at higher doses (>0.5?Gy) a steady increase was observed in each metabolite. This response was observed irrespective of dose-rate. Among the associations tested, cl, p, m-tyrosine and 3-nitrotyrosine revealed changes (p?相似文献   

Sulfonyl chromen-4-ones (CHW09) shows an additive effect to inhibit cell growth of X-ray irradiated oral cancer cells,involving apoptosis and ROS generation

Abstract

Purpose: This study evaluates the growth inhibiting potential of our previously described sulfonyl chromen-4-ones (CHW09) compound in X-ray irradiated oral cancer cells.

Materials and methods: The growth inhibiting effect and mechanism of combined CHW09/X-ray treatment was examined by analyzing cell viability, cell cycle, apoptosis, reactive oxygen species (ROS), and DNA damage.

Results: Individual treatments of CHW09 (10?μg/mL) and X-ray irradiation (12?Gy) slightly decreased cell viability of oral cancer Ca9-22 (87.25% and 86.54%) and CAL 27 (80.00% and 74.01%) cells and normal oral HGF-1 cells (92.76% and 87.56%) at 24?h-MTS assay, respectively. In a combined treatment (CHW09/X-ray), the cell viability in Ca9-22 and CAL 27 cells was significantly decreased to 73.48% and 59.07%, whereas HGF-1 cells maintained 84.97% viability in 24?h-MTS assay. For CAL 27 cells, both 72?h-MTS assay and clonogenic assay showed that CHW09/X-ray resulted in more growth inhibition than other treatments. Intracellular ROS levels of CHW09/X-ray were higher than for CHW09, X-ray and control. CHW09/X-ray and X-ray alone had higher G2/M arrest than the control and CHW09 alone. Moreover, flow cytometry and western blotting showed that CHW09/X-ray treatment caused higher apoptosis levels. Levels of H2A histone family member X (γH2AX)-based DNA damage and 8-oxo-2′-deoxyguanosine (8-oxodG)-oxidative DNA damage of CHW09/X-ray were higher than for CHW09, X-ray and control.

Conclusion: CHW09/X-ray treatment had additive growth inhibiting effects against X-ray irradiated oral cancer cells, partly attributing to apoptosis and ROS generation.     

Repetitive 50 Hz pulsed electromagnetic field ameliorates the diabetes-induced impairments in the relaxation response of rat thoracic aorta rings

Purpose: To evaluate the characteristic features of mechanical responses and the membrane potential changes induced by repetitive pulsed electromagnetic field (PEMF, 50 Hz, 5 mT) in thoracic aorta rings obtained from streptozotocin-induced diabetic and healthy control rats to determine if PEMF could ameliorate problems associated with diabetes.

Methods: Sixty male Wistar rats weighing 250–290 g were randomly divided into two experimental groups, each containing 30 animals. Streptozotocin was given via tail vein to produce diabetes mellitus (DM) in the first group rats. The second group rats were treated only with % 0.9 saline and considered as non-DM group. Both groups were also divided into two subgroups as DM + PEMF, DM + sham, PEMF and sham, each containing 15 animals. Although the DM + PEMF and PEMF groups were treated, the DM + sham and sham groups were not treated with PEMF. The PEMF treatment occurred four times daily for 30 min at 15-min intervals repeated daily for 30 days. Thoracic aorta rings from both DM and non-DM rats exposed to PEMF were evaluated for contraction and relaxation responses and membrane potential changes in the presence or absence of chemical agents that were selected to test various modes of action.

Results: Relaxation response of thoracic aorta rings was significantly reduced in DM than non-DM group. PEMF treatment significantly increased the relaxation response of the diabetic rings to acetylcholine, and reduced the concentration response to phenylephrine. Resting membrane potential was significantly higher in DM than in non-DM group. Inhibitors of nitric oxide (NO), both nitro-L-arginine (L-NO-ARG) and L-NO-ARG + indometacin combination, produced a significant transient hyperpolarisation in all groups. Inhibitors of potassium channel activity, charybdotoxin or apamine, produced a membrane depolarisation. However, PEMF did not induce any significant effect on the membrane potential in DM group.

Conclusions: Diabetes reduced the relaxation response of thoracic aorta rings. It also affected the membrane potentials of the rings. Treatment with PEMF ameliorated the diabetes-induced impairments in the relaxation response of these rings.     

电刺激C2C12细胞时活性氧生成的变化

目的:利用电刺激使C2C12细胞产生收缩运动,实时观察细胞内活性氧(ROS)生成的时相变化。方法:利用培养的C2C12细胞,电刺激使其产生收缩运动,测定细胞ROS生成速率、线粒体MDA含量、总SOD活性和胞浆内Na+,K+-ATPase活性。结果:(1)以45V、20ms5、Hz的强度刺激C2C12细胞,细胞内ROS生成迅速增加,在刺激60min时ROS的生成速率呈显著性升高(P<0.01),然后缓慢下降,继续刺激到120min时,ROS生成再次升高(P<0.01),随后迅速下降。(2)线粒体总SOD活性逐渐升高,至150min和180min时都与对照组相比有显著性差异(P<0.05);MDA量在90min时略有升高,随后下降,但无显著性差异。(3)电刺激C2C12细胞引起胞浆内Na+,K+-ATPase活性升高,刺激至180min时与刺激90min时相比酶活性显著下降(P<0.05)。结论:利用电刺激C2C12细胞模型,可实时测定收缩细胞的ROS生成速率变化,为运动性ROS产生的机理提供了直接证据。     

Tetrahydroporphyrin-tetratosylat (THPTS): A near-infrared photosensitizer for targeted and efficient photodynamic therapy (PDT) of human bladder carcinoma. An in vitro study

BackgroundEfficacy of PDT in muscle-invasive bladder cancer is hampered by low tissue penetration of most photosensitizers by short excitation wavelength. THPTS is excitable at near-infrared (760 nm) allowing tissue penetration up to 15 mm. We examined the cellular effects of THPTS-PDT in human bladder cancer cells.Material and methodsWe used four human transitional carcinoma cell lines, epithelial bladder progenitors (HBLAK) and bladder smooth muscle cells (HBSMC). We used flow cytometry to examine pharmacokinetics of THPTS, confocal laser scanning microscopy to analyze subcellular localization and production of reactive oxidative species (ROS), examined cytotoxicity and cell death pathways (qRT-PCR).ResultsTotal uptake varied between cell lines and was significantly high in HBLAK and HBSMC. Lysosomal localization was mainly seen in cancer cells and HBLAK, while THPTS was distributed throughout the cytoplasm in HBSMC. Significant ROS production was detected 30 min after THPTS-PDT. Growth arrest occurred within 4 h and resulted in apoptotic and necrotic cytotoxicity after 24 h. Cytotoxicity was dose-dependent and specifically high in cancer cells and HBLAK and significantly low in HBSMC.ConclusionTHPTS-PDT induces cellular mechanisms leading to cellular growth arrest, apoptosis and necrosis in human bladder cancer cells. These effects are only partly dependent on the total amount of THPTS uptake and rather dependent on its subcellular compartmentalization. HBSMC are hardly affected by THPTS-PDT confirming tumor specificity and safety. THPTS is a promising new photosensitizer with the unique advantage of deep tissue penetration allowing the treatment of solid tumors and warranting further animal studies.     

Reactive oxygen species mediates 50-Hz magnetic field-induced EGF receptor clustering via acid sphingomyelinase activation

Purpose: Exposure to extremely low frequency electromagnetic fields (ELF-EMFs) could elicit biological effects including carcinogenesis. However, the detailed mechanisms by which these ELF-EMFs interact with biological system are currently unclear. Previously, we found that a 50-Hz magnetic field (MF) exposure could induce epidermal growth factor receptor (EGFR) clustering and phosphorylation on cell membranes. In the present experiment, the possible roles of reactive oxygen species (ROS) in MF-induced EGFR clustering were investigated.

Materials and methods: Human amnion epithelial (FL) cells were exposed to a 50-Hz MF with or without N-acetyl-l-cysteine (NAC) or pyrrolidine dithiocarbamate (PDTC). EGFR clustering on cellular membrane surface was analyzed using confocal microscopy after indirect immunofluorescence staining. The intracellular ROS level and acid sphingomyelinase (ASMase) activity were detected using an ROS assay kit and an Amplex^® Red Sphingomyelinase Assay Kit, respectively.

Results: Results showed that exposure of FL cells to a 50-Hz MF at 0.4?mT for 15?min significantly enhanced the ROS level, induced EGFR clustering and increased ASMase activity. However, pretreatment with NAC or PDTC, the scavenger of ROS, not only counteracted the effects of a 50-Hz MF on ROS level and AMS activity, but also inhibited the EGFR clustering induced by MF exposure.

Conclusions: The present and previous data suggest that ROS mediates the MF-induced EGFR clustering via ASMase activation.     

Protection against radiation-induced oxidative damage by an ethanolic extract of Nigella sativa L.

Purpose:?An ethanolic extract of Nigella sativa L. (EE-NS) was investigated for its antioxidant properties and radioprotective effects against γ-radiation-induced oxidative damage.

Materials and methods:?The radical scavenging activity of the extract was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), deoxyribose degradation and plasmid relaxation assays in a cell-free system. DNA damage studies were performed using a single cell gel electrophoresis (SCGE) assay and micronuclei (MN) formation. Moreover, the alterations in lipid peroxidation and antioxidant enzymes were measured by biochemical methods.

Results:?EE-NS showed significant free radical scavenging and protection against DNA damage in cell free systems. Ex vivo treatment of mouse splenic lymphocytes with an ethanolic extract of N. sativa 1?h prior to irradiation (2 Gy) showed significant prevention of the formation of lipid-peroxides and intracellular reactive oxygen species (ROS), which correlated with radiation-induced apoptosis. Moreover, radiation-induced DNA damage was significantly prevented in splenocytes pre-treated with EE-NS. Swiss albino mice fed orally with the different doses of EE-NS (0–100?mg/kg bw) for five consecutive days followed by 2 Gy whole body irradiation (WBI) showed significant protection against oxidative injury to spleen and liver as measured by lipid peroxidation and the activity of antioxidant enzymes. These results were correlated with the prevention of DNA damage as measured by bone marrow micronuclei assay. Our results suggest that oral feeding of extract resulted in increased survival in mice exposed to WBI (7.5 Gy).

Conclusion:?The results obtained from the different experimental systems suggest the radioprotective ability of EE-NS involving prevention of radiation-induced oxidative damage.     

Inhibition of UVB-induced oxidative damage and apoptotic biochemical changes in human lymphocytes by 2,5-dihydroxy-3-undecyl-1,4-benzoquinone (embelin)

Abstract

Purpose: The present study investigates the inhibition of Ultraviolet B (UVB, 290–320 nm) radiation-induced oxidative damage in peripheral blood human lymphocytes by embelin extracted from Embelia ribes.

Materials and methods: Embelin was extracted, purified and characterized. Prior to inhibitory assessment, a maximum concentration of embelin that was non-toxic was determined. Six experimental groups, including respective controls were made to assess the inhibitory effect of embelin for the selected concentrations of 10 and 20 μg/ml. For the experimental groups; lymphocytes (1 × 10⁶ cells) were pre-treated with the chosen concentration of embelin for a period of 60 min and then exposed to UVB for 30 min. UVB radiation inhibitory effect of embelin assessed by measuring antioxidant and lipid peroxidation levels, deoxyribonucleic acid (DNA) damage, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) at scheduled time points after irradiation.

Results: Pre-treatment of lymphocytes with embelin prevents UVB-induced oxidative damage. An increase in antioxidant levels in irradiated cells in the presence of embelin and UV absorbance of embelin could be the reason for the decrease in lipid peroxidation level and prevention of DNA damage by UVB radiation.

Conclusion: Embelin prevents oxidative stress induced by UVB irradiation via its antioxidant property.     

Exposure to a 50-Hz magnetic field induced mitochondrial permeability transition through the ROS/GSK-3β signaling pathway

Purpose To investigate the biological effects of a 50-Hz magnetic field (MF) on mitochondrial permeability.

Materials and methods Human amniotic epithelial cells were exposed to MF (50?Hz, 0.4?mT) for different durations. Mitochondrial permeability, mitochondrial membrane potential (ΔΨm), cytochrome c (Cyt-c) release and the related mechanisms were explored.

Results Exposure to the MF at 0.4?mT for 60?min transiently induced mitochondrial permeability transition (MPT) and Cyt-c release, although there was no significant effect on mitochondrial membrane potential (ΔΨm). Other than decreasing the total Bcl-2 associated X protein (Bax) level, MF exposure did not significantly affect the levels of Bax and B-cell lymphoma-2 (Bcl-2) in mitochondria. In addition, cells exposed to the MF showed increased intracellular reactive oxidative species (ROS) levels and glycogen synthase kinase-3β (GSK-3β) dephosphorylation at 9 serine residue (Ser⁹). Moreover, the MF-induced MPT was attenuated by ROS scavenger (N-acetyl-L-cysteine, NAC) or GSK-3β inhibitor, and NAC pretreatment prevented GSK-3β dephosphorylation (Ser⁹) caused by MF exposure.

Conclusion MPT induced by MF exposure was mediated through the ROS/GSK-3β signaling pathway.     

New insight into mitochondrial changes in vascular endothelial cells irradiated by gamma ray

Purpose: To investigate alterations of mitochondria in irradiated endothelial cells to further elucidate the mechanism underlying radiation-induced heart disease.

Materials and methods: Experiments were performed using human umbilical vein endothelial cells (HUVECs). HUVECs were irradiated with single gamma ray dose of 0, 5, 10 and 20?Gy, respectively. Apoptosis was assessed by flow cytometry at 24, 48 and 72?h post-irradiation, respectively. The intracellular reactive oxygen species (ROS) was measured with 2′,7′-dichlorofluorescein-diacetate (DCFH-DA) at 24?h post-irradiation. Mitochondrial membrane potential (ΔΨm) by JC-1 and the opening of mitochondrial permeability transition pore (mPTP) by a calcein-cobalt quenching method were detected at 24?h post-irradiation in order to measure changes of mitochondria induced by gamma ray irradiation.

Results: Gamma ray irradiation increased HUVECs apoptosis in a dose-dependent and time-dependent manner. Irradiation also promoted ROS production in HUVECs in a dose-dependent manner. At 24?h post-irradiation, the results showed that irradiation decreases ΔΨm, however, paradoxically, flow cytometry showed green fluorescence instensity higher in irradiated HUVECs than in control HUVECs in an irradiation dose-dependent manner which indicated gamma ray irradiation inhibited mPTP opening in HUVECs.

Conclusions: Gamma ray irradiation induces apoptosis and ROS production of endothelial cells, and decreases ΔΨm meanwhile contradictorily inhibiting the opening of mPTP.     

Ferulic acid (FA) abrogates ionizing radiation-induced oxidative damage in murine spleen

Purpose: The spleen is a crucial organ manifesting immune functions. Thus, radiation-induced oxidative challenge is vulnerable for the spleen. Our major objective was to protect the spleen from radiation-induced anomalous situations and to identify the signaling pathways involved.

Materials and methods: Swiss albino mice were treated with ferulic acid (FA) once in a day at a dose of 50?mg/kg body weight for 5 consecutive days before exposing them to single dose of 10?Gy irradiation. The ROS generation and MMP change were determined by flow cytometry. The expression of different signaling proteins was investigated by immunoblotting and immunocytochemistry.

Results: FA pretreatment significantly prevented radiation-induced oxidative stress by downregulating TBARS formation and by upregulating SOD and catalase activity. FA scavenged ROS, prevented the alteration of MMP and downregulated the expression of stress marker Cdc42 and apoptotic markers p⁵³, p²¹, Bax and PTEN. Cell cycle analysis showed DNA damage induced arrest of cells at subG0/G1 phase. Moreover, pretreatment with FA augmented Bcl2 expression and also increased the level of p-PI3K.

Conclusion: FA prevented the activation of apoptotic signaling events in the spleen by interfering with the free radical chain reaction and by scavenging superfluous ROS. This is perhaps the first comprehensive study with a mechanistic viewpoint that FA can protect the spleen from ionizing radiation.     

Long-term exposure of cockroach Blaptica dubia (Insecta: Blaberidae) nymphs to magnetic fields of different characteristics: effects on antioxidant biomarkers and nymphal gut mass

Abstract

Purpose: The main goal of this study was to analyze the long-term effects of static (SMF) and extremely low-frequency magnetic field (ELF MF) on nymphal gut mass and antioxidant biomarkers in this tissue of cockroach Blaptica dubia.

Materials and methods: One-month-old nymphs were exposed to magnetic field (MF) for 5 months in three experimental groups: control, exposure to SMF (110?mT) and exposure to ELF MF (50?Hz, 10?mT).

Results: The gut masses of the MF groups were significantly lower when compared to control. Superoxide dismutase (SOD) and catalase (CAT) activities were markedly higher than for the control and the differences between the MF groups were statistically significant only for SOD. The applied MF had no effect on total glutathione (GSH) content. Glutathione reductase (GR) and glutathione S-transferase (GST) activities were significantly lower in both MF groups in comparison to the control. There was a significant difference between MF groups for GR activity. Principal Component Analysis (PCA) showed that CAT and GST were the main factors contributing to the differentiation of the control group from the treated experimental groups along PCA 1, and SOD and GR along PCA 2. PCA revealed clear separation between experimental groups depends on antioxidant biomarker response.

Conclusion: The applied magnetic fields could be considered a potential stressor influencing gut mass, as well as examined antioxidative biomarkers.     

The effect of red-to-near-infrared (R/NIR) irradiation on inflammatory processes

Abstract

Introduction: Near-infrared (NIR) and red-to-near-infrared (R/NIR) radiation are increasingly applied for therapeutic use. R/NIR-employing therapies aim to stimulate healing, prevent tissue necrosis, increase mitochondrial function, and improve blood flow and tissue oxygenation. The wide range of applications of this radiation raises questions concerning the effects of R/NIR on the immune system.

Methods: In this review, we discuss the potential effects of exposure to R/NIR light on immune cells in the context of physical parameters of light.

Discussion: The effects that R/NIR may induce in immune cells typically involve the production of reactive oxygen species (ROS), nitrogen oxide (NO), or interleukins. Production of ROS after exposure to R/NIR can either be inhibited or to some extent increased, which suggests that detailed conditions of experiments, such as the spectrum of radiation, irradiance, exposure time, determine the outcome of the treatment. However, a wide range of immune cell studies have demonstrated that exposure to R/NIR most often has an anti-inflammatory effect. Finally, photobiomodulation molecular mechanism with particular attention to the role of interfacial water structure changes for cell physiology and regulation of the inflammatory process was described.

Conclusions: Optimization of light parameters allows R/NIR to act as an anti-inflammatory agent in a wide range of medical applications.     

Seventh Annual Meeting of the Radiation Research Society

Purpose:?To investigate the effects of ataxia telangiectasia mutated (ATM)-regulated reactive oxygen species (ROS) and cell death pathways on the response of U87MG glioma cells to ionising radiation (IR) and oxidative stress.

Material and methods:?ATM expression was blocked in U87MG glioma cells using a small interfering RNA (siRNA) technique. Cell survival, sub-lethal damage (SLD), and potential lethal damage (PLD) repair following IR were assessed by clonogenic assay while changes in intracellular ROS, the apoptosis, and autophagy were followed by flow cytometry and Western blotting.

Results:?Blocking ATM expression in U87MG cells increased intracellular ROS levels and sensitivity to the cytotoxic effects of IR and oxygen stress; effects that could be partly counteracted by the antioxidant N-acetylcysteine (NAC). Knock down of ATM rendered cells unable to repair sub-lethal or potentially lethal damage and DNA double strand breaks (DSB) after IR exposure; something that NAC could not counteract. ATM did control the pathways a cell used to die following IR and this did seem to be ROS-dependent.

Conclusion:?ATM is involved in redox control but ROS elevations following ATM knock down seem more involved in the decision as to what cell death pathway is utilised after IR than DSB repair and radiosensitivity.     

Exposure to a 50-Hz magnetic field induced ceramide generation in cultured cells

Purpose To investigate the effects of a 50-Hz magnetic field (MF) exposure on ceramide metabolism, as well as the cascade downstream signaling pathways in human amniotic (FL) cells.

Materials and methods FL cells were exposed to MF at 0.4?mT for different durations (from 5–60?min). The ceramides levels were analyzed with high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The activity of cathepsin D was assayed using a fluorometric assay kit, and the activity of protein phosphatase 2A (PP2A) was examined by Western blotting. After exposing to MF at 0.4?mT for 60?min with sequential culture for different durations (0, 3, 6, 12 or 36?h), the rate of cell apoptosis was assessed by flow cytometry.

Results Exposing cells to MF at 0.4?mT for different durations caused a significant increase in ceramide production via de novo synthesis and hydrolysis of sphingomyelin (SM), and the effect was different according to the exposure time. However, no significant change in cell apoptosis was detected after MF exposure for 60?min with sequentially culturing for up to 36?h. In addition, increase in ceramide did not activate its downstream signal molecules, cathepsin D and PP2A, which are usually closely related to apoptosis of cells.

Conclusions Exposure to a 50-Hz MF could raise ceramide levels but had no significant effect on apoptosis in cultured cells.     

Halofuginone enhances the anti-tumor effect of ALA-PDT by suppressing NRF2 signaling in cSCC

Background5-aminolevulinic acid-mediated PDT (ALA-PDT) has been used in a variety of skin diseases including cSCC (cutaneous squamous cell carcinoma). Halofuginone (HL) is a less-toxic febrifugine derivative and has inhibitory effects on a variety of cancer cells. For now, there are no published study focusing on the combination use of ALA-PDT with HL to improve clinical efficacy of cSCC.ObjectiveIn this study, we will examine the effectiveness of combined treatment of ALA-PDT and HL in cSCC as well as its underlying mechanism.MethodsThe human epidermoid carcinoma cell line SCL-1 was treated with ALA-PDT or/ and HL, and cell viability, cell migration, ROS production, apoptosis were evaluated by CCK-8, colony formation, scratch assay, DCFH-DA probe, flow cytometry, respectively. The protein expression of NRF2 signaling was examined by western blot.ResultsHL strengthened ALA-PDT's inhibition of SCL-1 cell viability, migration, as well as NRF2 related β-catenin, p-Erk1/2, p-Akt and p-S6K1 expression. Overexpression of NRF2 conferred resistance to co-treatment's effects on c-Myc, Cyclin D1, Bcl-2, as well as cell proliferation. HL also strengthened ALA-PDT's inhibition of tumor volume in cSCC mouse model and elevated ROS generation of ALA-PDT.ConclusionHL enhances the anti-tumor effect of ALA-PDT in vitro and in vivo. HL has the potential to enhance the anti-tumor effect of ALA-PDT in cSCC via inhibiting NRF2 signaling.