[Effects of Electromagnetic Pulses on Exosomes Secretion by A549 Cells].

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.