Tumor-Treating Fields Induce RAW264.7 Macrophage Activation Via NK-?B/MAPK Signaling Pathways

Park, Jeong-In; Song, Kyung-Hee; Jung, Seung-Youn; Ahn, Jiyeon; Hwang, Sang-Gu; Kim, Joon; Kim, Eun Ho; Song, Jie-Young

To investigate the effect of TTFs on macrophages, RAW 264.7 cells were treated with TTFs (0.9 V/cm) or LPS, which is a representative activator of macrophages. 13 The morphological changes were observed under a phase contrast microscope ( Figure 1A ). The normal morphology of RAW 264.7 cells was round in the control group. In contrast, LPS-treated cells showed polygonal and dendritic-like morphology, indicating that LPS effectively activated RAW 264.7 cells. 14 In TTFstreated cells, the dendritic-like shape was observed in a portion of the population, but the number of cells seemed to be decreased at 48 hours compared to that in other groups. Therefore, the cell viability was determined by a trypan blue dye exclusion assay. As shown in Figure 1B , LPS-stimulated and unstimulated control cells continuously proliferated, whereas RAW 264.7 cells treated with TTFs exhibited cell growth inhibition but without a statistically significant influence on cell viability.