Background and objective Numerous researches indicated that electromagnetic pulses (EMP) possessed advantages such as strong targeting, minimal side-effects and low treatment cost in tumor therapy, but its optimum parameters for treatment and the relationship between EMP and tumor-derived exosomes remains unclear. This study aims to clarify the effects of EMP with different parameters on the quantity and miRNA (microRNA) of exosomes secreted by human non-small cell lung cancer A549 cells, providing beneficial reference for the clinical application of EMP and related research. Methods A549 cells were randomly divided into control group and different EMP radiation groups with respective intensity of 400, 600 and 800 kV/m. EMP was performed with 2000 pulses once, 20 Hz of repetition frequency and 120 ns of pulse width. A549 cells were radiated once per day for continuous 3 days. After radiation, exosomes were collected and identified; cell number was measured by trypan blue staining; the concentration of exosomes was measured by nanoparticle tracking analysis (NTA); the abundance of miRNAs was determined by miRNA sequencing. Results Compared with control group, the morphology and cell viability of A549 cells in radiation group was not different, but the quantity of exosomes in 400 or 800 kV/m radiation group was significantly decreased (P<0.05), in contrast with obvious increase in 600 kV/m radiation group (P<0.05). The abundance of exosomal miRNAs between control group and each EMP group was obviously different (P<0.05) and target genes of differentially abundant miRNAs enriched in different pathways. Conclusion Under the experimental condition, the quantity and miRNA abundance of exosomes could be changed by EMP radiation, which could further influence the function of tumor-derived exosomes.

Mounting literature indicates that electromagnetic pulses (EMP) is the promising modality to treat cancers with advantages such as noninvasiveness and few side-effects, but its appropriate parameters and underlying mechanisms such as its influence on tumor-derived exosomes (TDEs) are largely unknown. This study aimed to elucidate effects of EMP, exosome inhibition and their coaction on A549 lung adenocarcinoma cells. A549 cells were randomly divided into control group, GW4869 group treated by 20 μM GW4869, vehicle group treated by dimethyl sulfoxide, EMP group treated by EMP exposure, and EMPG group treated by EMP exposure combined with 20 μM GW4869. After EMP exposure, cell proliferation was determined by CCK8 assay, cell cycle and apoptosis was detected by flow cytometry, and cell migration was determined by transwell assay. The results showed that EMP or exosomes inhibition did not affect cell proliferation, cell cycle, apoptosis and cell migration (p > 0.05), but cell migration in EMPG group was significantly decreased compared with vehicle group (p < 0.05). We concluded that under the experimental condition, EMP or GW4869 alone had no effects on behaviors of A549 cells, but their coaction could effectively inhibit the migration of A549 cells.

目的 探讨1 800 MHz电磁辐射对NIH/3T3细胞周期和凋亡的影响.方法 将NIH/3T3细胞假暴露或间断暴露(5 min开,10 min关)在比吸收率(specific absorption rate,SAR)为2 W/kg,模拟全球移动通信系统(global system for mobile communications,GSM)通话状态信号的1 800 MHz电磁场中.每天暴露5h,连续60 d,期间每3～4 d传代一次.暴露完毕后,用Cell Counting Kit-8(CCK-8)检测细胞活性;染色后用流式细胞仪检测细胞凋亡、细胞周期的变化;用Caspase-3活性检测试剂盒检测细胞凋亡因子Caspase-3的活性变化.结果 与假暴露组相比,暴露组细胞活力下降且培养96 h后明显下降(t=30.78,P=0.048);暴露组细胞处于S期(t=3.267,P=0.022)和G2期(t=3.844,P=0.022 9)的百分数较假暴露组有明显增加;细胞凋亡率明显增加(t=3.349,P=0.047),Caspase-3活性增高(t=13.593,P=0.013).结论 NIH/3T3细胞经60d 1 800 MHz模拟手机电磁辐射后,细胞活性下降,S期和G2期阻滞,同时细胞凋亡率增加.

[目的]研究900MHz、最大功率密度为10.644μW/cm2的手机射频辐射对体外细胞DNA损伤和病毒癌基因EB病毒早期抗原(EBV-EA)的激活作用. [方法] (1)将NIH/3T3细胞分别暴露在手机辐射下0、1、2、4、6、8、12h,并分别设定相应的正常对照组,用彗星电泳检测细胞DNA受损程度.(2)将Raji细胞分为A辐照(-)TPA(-)、B辐照(-)TPA(+)、C辐照(+)TPA(-)、D辐照(+)TPA(+)4组,接受手机辐照,强度为4h/d,实验持续4周;每周结束时,B和D两组细胞分别使用促癌剂12-0-十四烷酰佛波醇-13-乙酸酯(TPA)1ng/mL处理48h.用免疫细胞化学检测各组细胞中EBV-EA的阳性表达情况. [结果]当NIH/3T3细胞辐照2h后,与对照组相比细胞Olive尾距有明显差异(P＜0.05),但在随后的2～12h内的各个检测时间点上,Olive尾距并没有随着时间的增加而增加(P＞0.05); Raji细胞在实验4周后,辐照C、D组细胞的EBV-EA阳性表达率较A组明显增加(P＜0.05),并且在加入促癌剂TPA的D组,阳性表达率更加明显(P＜0.01). [结论] 900 MHz手机射频辐射会对细胞DNA产生一定的损伤,并且能够激活EBV-EA的表达.

To investigate the potential adverse effects of mobile phone radiation, we studied reactive oxygen species (ROS), DNA damage and apoptosis in mouse embryonic fibroblasts (NIH/3T3) after intermittent exposure (5 min on/10 min off, for various durations from 0.5 to 8 h) to an 1800-MHz GSM-talk mode electromagnetic radiation (EMR) at an average specific absorption rate of 2 W/kg. A 2',7'-dichlorofluorescin diacetate fluorescence probe was used to detect intracellular ROS levels, immunofluorescence was used to detect gamma H2AX foci as a marker for DNA damage, and flow cytometry was used to measure apoptosis. Our results showed a significant increase in intracellular ROS levels after EMR exposure and it reached the highest level at an exposure time of 1 h (p < 0.05) followed by a slight decrease when the exposure continued for as long as 8 h. No significant effect on the number of gamma H2AX was detected after EMR exposure. The percentage of late-apoptotic cells in the EMR-exposed group was significantly higher than that in the sham-exposed groups (p < 0.05). These results indicate that an 1800-MHz EMR enhances ROS formation and promotes apoptosis in NIH/3T3 cells.

[Objective] The aim was to determine whether the concentration and addition sequence of DNA breaking agent have effect on DNA crosslinking detection in Single Cell Gel Ectrophoresis(SCGE).[Method] Carmustine(BCNU),a tumor drug,was used as DNA crosslinking agent,and tert-butyl hydroperoxide(tBHP) as DNA breaking agent.The effect of addition sequence and concentration of tBHP on BCNU DNA crosslinking was assessed by the Tail-length in SCGE.T-test was performed to indicate statistical significance.[Result] There was no significant difference between the tBHP pre-treatment and post-treatment in tail-length.Moreover,the DNA fracture was increased with the rise of tBHP concentration,and 400 μmol/L showed a marked DNA breaking effect.[Conclusion] tBHP addition sequence has no effect on DNA crosslinking detection,and concentration 400 μmol/L was the best dose in DNA breaking.

OBJECTIVE:To investigate the effect of long-term power frequency electromagnetic field (50 Hz) exposure on the proliferation and apoptosis of human lens epithelial cells (SRA01/04 cells). METHODS:SRA01/04 cells in the exponential growth phase were exposed or sham-exposed to power frequency electromagnetic field (50 Hz, 2.3 mT) for 2 hours per day, 5 days every week. After 11 weeks of exposure, the cells were collected; the cell morphology was observed under a microscope, the cell viability was measured by MTT assay, the cell cycle and apoptosis were examined by flow cytometry, and the protein expression levels of cyclin D and proliferating cell nuclear antigen (PCNA) were determined by western blot. RESULTS:Compared with the sham-exposed SRA01/04 cells, most exposed cells became rounded and more stereoscopic, and heterochromatin gathered near the nuclear membrane in some exposed cells. The MTT assay showed that the viability of exposed cells was significantly increased compared with that of the sham-exposed cells (P < 0.05). Long-term power frequency electromagnetic field exposure led to significantly increased number of cells in S phase (P < 0.05), and the proliferation index was significantly higher in the exposed cells than in the sham-exposed cells (P < 0.05). There was no significant difference in apoptotic rate between the exposed cells and sham-exposed cells (P > 0.05). The exposed cells had significantly higher protein expression levels of cyclin D and PCNA than the sham-exposed cells (P < 0.05). CONCLUSION:Long-term power frequency electromagnetic field exposure can promote cellular proliferation and change cell cycle in SRA01/04 cells, but it has no marked effect on the apoptosis of SRA01/04 cells.