The Influence of the Extremely Low Frequency Electromagnetic Field on Clear Cell Renal Carcinoma

Abstract

The development of new technologies and industry is conducive to the increase in the number and variety of electromagnetic field (EMF) sources in our environment. The main sources of EMF are high-voltage lines, household appliances, audio/video devices, mobile phones, radio stations, and radar devices. In the growing use of electronic devices, scientists are increasingly interested in the effects of EMF on human health. Even though many studies on the effects of EMF have already been carried out, none of them has shown a significant effect on mammals, including humans. Moreover, it is not entirely clear how EMF influences cell behavior. The International Agency for Research on Cancer on 31 May 2011, classified PEM as a possible carcinogenic factor. This study aimed to investigate the effect of the electromagnetic field on morphological and functional changes in clear cell renal carcinoma. The research was carried out on in vitro cultures of four cell lines: HEK293, 786-O 769-P, and Caki1. The results of the research showed that the EMF of low frequency had a slight effect on the viability of cells. EMF, which induced cell arrest in the G1 phase, increased the number of early apoptotic cells and decreased the number of viable cells in the 786-O line. EMF did not affect the proliferation and viability of HEK293 cells. Extreme low-frequency EMF (ELF-EMF) also showed an inhibitory effect on the migration and metastatic properties of clear cell kidney cancer cells. Moreover, shortly after the end of ELF-EMF exposure, significant increases in ROS levels were observed in all tested cell lines. As part of the work, it was shown that low-frequency EMF shows an inhibitory effect on the proliferation of primary cancer cells, diminishing their migratory, invasive, and metastatic abilities. It also increases the apoptosis of cancer cells and the amount of reactive oxygen species. Based on the results of our research, we want to point up that the effect of ELF-EMF depends on a specific metabolic state or at a specific stage in the cell cycle of the cells under study.

Keywords: EMF; cancer; ccRCC; electromagnetic field; kidney; renal carcinoma.

Figure 1

Results of cytometric analysis of cell cycle phases under the influence of 4.5 mT, 50 Hz extreme low-frequency electromagnetic field (ELF-EMF). Data presented as mean ± standard deviation: *—p < 0.05, **—p < 0.005, ***—p < 0.001, **** p < 0.0001.

Figure 2

Results of the cytometric analysis of cell apoptosis under the influence of 4.5 mT, 50 Hz ELF-EMF. Data presented as mean ± standard deviation: *—p < 0.05.

Figure 3

The results of the cytometric analysis of the% cells that produced reactive oxygen species under the influence of 4.5 mT, 50 Hz ELF-EMF. Data presented as mean ± standard deviation: **** p < 0.0001.

Figure 4

Number of cells migrating towards chemoattractant (average of 5 fields at 100× total magnification). (***—p < 0.0005; ****—p < 0.00005).

Figure 5

The analysis of the diameter of the spheroid was carried out in 24, 48, and 72 h, the mean values of the diameters of the spheres are presented in the diagram. The analysis was performed with the DLT-Cam Viewer software and the measurements were made from two independent experiments with nine replications. (*—p < 0.05; ***—p < 0.0005).

Figure 6

HEK293 cells in hanging drop culture. (A–C) show HEK293 cells from the control group 24, 48, and 72 h from the start of the culture, respectively. (D–F) show HEK293 cells exposed to 4.5 mT, 50 Hz EMF 24, 48, and 72 h from cultivation, respectively. Pictures taken with the Delta-Optical IB-100 microscope, 4× magnification.

Figure 7

Caki1 cells in hanging drop culture. (A–C) show Caki1 cells from the control group 24, 48, and 72 h from the start of the culture, respectively. (D–F) show Caki1 cells exposed to 4.5 mT, 50 Hz EMF 24, 48, and 72 h from cultivation, respectively. Pictures taken with the Delta-Optical IB-100 microscope, 4× magnification.

Figure 8

786-O cells in hanging drop culture. (A–C) show 786-O cells from the control group 24, 48, and 72 h from the start of the culture, respectively. (D–F) show 786-O cells exposed to 4.5 mT, 50 Hz EMF 24, 48, and 72 h from cultivation, respectively. Pictures taken with the Delta-Optical IB-100 microscope, 4× magnification.

Figure 9

769-P cells in hanging drop culture. (A–C) show 769-P cells from the control group 24, 48, and 72 h from the start of the culture, respectively. (D–F) show 769-P cells exposed to 4.5 mT, 50 Hz EMF 24, 48, and 72 h from cultivation, respectively. Pictures taken with the Delta-Optical IB-100 microscope, 4× magnification.