BACKGROUND: 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. CONCLUSIONS 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.
Humans ; Exosomes/genetics* ; A549 Cells ; MicroRNAs/metabolism* ; Lung Neoplasms/pathology* ; Cell Survival/radiation effects* ; Electromagnetic Fields

From the view point of drug approval, the research in quality standard and stability of Chinese new drug must be emphasized in order to produce safe and effective new drugs which are competitive in the world. Forthermore, the regulations for new drug approval should be learned repeatedly so as to raise the level of new drug application.