Abstract 5692: Low frequency electromagnetic field suppresses macrophage phagocytosis

The purpose of this study is to determine the role of low frequency electromagnetic fields (EMF) on human macrophages and their inflammatory response. The effects of EMF on humans are highly dependent on frequencies. Studies have shown that low EMF (25-30 Hz) frequencies can help lower inflammation and suppress pain, as well as induce healing in benign prostatic hyperplasia. Macrophages are known for their pro-inflammatory responses against foreign antigens and their anti-inflammatory and angiogenic responses in cancer. We wanted to determine the effects of 27Hz EMF on macrophage phagocytosis and gene expression to determine whether low frequency EMF can decrease inflammation. This can help us understand the role of low frequency EMF in macrophage function. This may provide further insight as to how macrophages may be affected when fighting disease, especially cancer. We incubated the monocytic cell line U937 with 200-400 ng of phorbol-12 myristate 13-acetate (PMA) for 24 hours to allow for differentiation into macrophages. Once cells had differentiated, we stained the cells with the eFluor 670 dye for 30 minutes. The cells were then washed and plated in 12-well plates at 1X106 cells/mL and allowed to attach for 15 minutes. Cells were exposed to 27 Hz EMF treatment for 30 or 60 minutes or no exposure at all (control). After EMF treatment, a solution of PE fluorescent beads was added to the cells. U937 cells were allowed to phagocytose for 60 minutes. Engulfment levels were then measured with Flow Cytometry and results were analyzed with FlowJo Software. The percentage of macrophages involved in engulfment of 1 bead, 2 beads, and 3+ beads were determined. With 30 minutes of 27Hz EMF treatment the macrophages showed a significant reduction in total engulfment compared to the control. When looking at the percentages of macrophages that engulfed 1 bead or 2 beads, a higher percentage of treated macrophages engulfed 1 bead and a similar percentage engulfed two beads as compared to the control. Interestingly, the percentage of macrophages that engulfed 3+ beads was reduced significantly. This suggests 30 minutes of exposure to EMF treatment decreased the aggressiveness of the macrophages. In contrast, after 60 minutes of exposure to EMF treatment, the total engulfment percentage increased by more than 5%. This was seen by a higher percentage of cells participating in engulfment of 3+ beads as compared to the control. In conclusion, we observed that with 30 minutes of exposure, macrophages tend to be less aggressive but after 60 minutes a shift in aggressiveness is observed. Our research implies that macrophages can be induced to a more aggressive state with 60 minutes of electromagnetic field treatment. Further research is ongoing to understand the effects of different time intervals of EMF treatment on macrophages. Citation Format: Weston Scot Burrup, Evita G. Weagel, Richard A. Robison, Kim L. O9Neill. Low frequency electromagnetic field suppresses macrophage phagocytosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5692.