黑色素瘤是最危險的皮膚癌類型，是一種特別具有攻擊與侵襲性的腫瘤。黑色素瘤患者接受化療或手術治療後，易造成癒後不良。因此，使用電磁場來抑制黑色素瘤的侵襲和生長，可成為癌症治療的新途徑。越來越多研究表明，不同頻率類型的電磁場對黑色素瘤B16-F10癌細胞的生長有抑制作用。大多數研究都是針對單一頻率或市電頻率(60 Hz)對細胞的抑制效果。本研究使用極低頻掃頻頻率電磁場（7.83 Hz，掃頻範圍±0.1、±0.3、±0.5、±1、±2 Hz之舒曼共振頻率）對B16-F10癌細胞暴露48小時的影響。並使用細胞活性染劑(MTT)和鈣螢光染料(Fluo-4 AM)檢測癌細胞的細胞活性與細胞內鈣螢光。結果顯示，B16-F10癌症細胞在舒曼共振頻率7.83 Hz ± 0.3 Hz 掃描間隔 0.1 Hz時有最佳抑制率(25.5 %)，且抑制率與細胞內鈣濃度呈正比例。接著使用變焦快速傅里葉分析（Zoom FFT）方法分析掃頻磁場暴露細胞的持續時間。分析結果顯示，舒曼頻率7.83 Hz之磁場暴露時間大於2.3小時以上時，抑制率為21.4 %~ 25.45%。當掃頻範圍頻率高於± 1 Hz跟± 2 Hz時，癌細胞抑制效果分別減少6%和12%。結果顯示，舒曼波掃頻磁場對黑色素腫瘤細胞有最明顯的抑制效果。

Melanoma is the most dangerous type of skin cancer because it is a particularly aggressive form of tumor. Patients with invasive melanoma have a poor prognosis following surgery or treatment with chemotherapies, and hence the use of an extremely low frequency electromagnetic field (ELF-EMF) is an alternative treatment method that could alter melanoma invasion and growth. Therefore, researchers are increasingly investigating the inhibitory effects of different EMF frequency types on B16-F10 cancer cells.
In this study, we used the Schumann resonance frequency (7.83 Hz) on cell with melanoma combined with ELF-EMF exposure for 48 hr to influence B16-F10 cancer cells. Additionally, we used different sweep frequency ranges (step intervals 0.1 and 0.05 Hz) around 7.83 Hz to explore the different biological responses. We detected the viability of cancer cells via 3-(4, 5-dimethythiazol-2-y1)-2, 5-dipheny1 tetrazolium bromide (MTT assay) and used the calcium fluorescence dye Fluo-4 AM to show intracellular calcium fluorescence, which is positively proportionate to intracellular calcium concentration. The Schumann sweep frequency (7.83 ± 0.3 Hz) had the highest inhibitory rate (25.5%) on cell viability. Furthermore, we used the zoom fast Fourier transform method to analyze the sweep frequency spectrum’s magnetic field exposure in terms of cell duration time. The cell inhibition rate was 21.4–25.45% when B16-F10 cells were exposed to a 7.83-Hz EMF for more than 2.3 hr. Moreover, the cell inhibition rate decreased 6% and 12% for sweep frequencies at ± 1 Hz and ± 2 Hz, respectively. Thus, the experimental results showed an obviously inhibitory effect around 7.83 Hz frequency spectrum with different frequency sweep intervals.

[1] Ćosić, I., Cvetković, D., Fang, Q., & Lazoura, H. (2006). Human electrophysiological signal responses to ELF Schumann resonance and artificial electromagnetic fields. FME Transactions, 34(2), 93–103.
[2] Zhadin, M. N. (2001). Review of Russian literature on biological action of DC and low‐frequency AC magnetic fields. Bioelectromagnetics, 22(1), 27–45.
[3] Füllekrug, M. (1995). Schumann resonances in magnetic field components. Journal of Atmospheric and Terrestrial Physics, 57(5), 479–484.
[4] Berg, H. (1999). Problems of weak electromagnetic field effects in cell biology. Bioelectrochemistry and Bioenergetics, 48(2), 355–360.
[5] Brighton, C. T., Wang, W., Seldes, R., Zhang, G., & Pollack, S. R. (2001). Signal transduction in electrically stimulated bone cells. The Journal of Bone & Joint Surgery, 83(10), 1514–1523.
[6] Ross, C. L., Siriwardane, M., Almeida-Porada, G., Porada, C. D., Brink, P., Christ, G. J., & Harrison, B. S. (2015). The effect of low-frequency electromagnetic field on human bone marrow stem/progenitor cell differentiation. Stem Cell Research, 15(1), 96–108.
[7] Buckner, C. A., Buckner, A. L., Koren, S. A., Persinger, M. A., & Lafrenie, R. M. (2015). Inhibition of cancer cell growth by exposure to a specific time-varying electromagnetic field involves T-type calcium channels. PLoS One, 10(4), e0124136.
[8] Chen, Y. C., Chen, C. C., Tu, W., Cheng, Y. T., & Tseng, F. G. (2010). Design and fabrication of a microplatform for the proximity effect study of localized ELF-EMF on the growth of in vitro HeLa and PC-12 cells. Journal of Micromechanics and Microengineering, 20(12), 125023.
[9] Nie, Y., Du, L., Mou, Y., Xu, Z., Weng, L., Du, Y., & Wang, T. (2013). Effect of low frequency magnetic fields on melanoma: Tumor inhibition and immune modulation. BMC Cancer, 13(1), 582.
[10] Wang, T., Nie, Y., Zhao, S., Han, Y., Du, Y., & Hou, Y. (2011). Involvement of midkine expression in the inhibitory effects of low‐frequency magnetic fields on cancer cells. Bioelectromagnetics, 32(6), 443–452.
[11] Novikov, V. V., Novikov, G. V., Fesenko, E. E. (2009). Effect of weak combined static and extremely low‐frequency alternating magnetic fields on tumor growth in mice inoculated with the Ehrlich ascites carcinoma. Bioelectromagnetics, 30(5): 343–351.
[12] Zimmerman, J. W., et al. (2012). Cancer cell proliferation is inhibited by specific modulation frequencies. British Journal of Cancer, 106(2): 307.
[13] Tang, R., et al. (2016). Extremely low frequency magnetic fields regulate differentiation of regulatory T cells: Potential role for ROS‐mediated inhibition on AKT. Bioelectromagnetics, 37(2): 89–98.
[14] Roderick, H. L., & Cook, S. J. (2008). Ca2+ signalling checkpoints in cancer: Remodelling Ca2+ for cancer cell proliferation and survival. Nature Reviews Cancer, 8(5): 361.
[15] Tsai, M.‐T. et al. (2009). Modulation of osteogenesis in human mesenchymal stem cells by specific pulsed electromagnetic field stimulation. Journal of Orthopaedic Research, 27(9): 1169–1174.
[16] Simko, M., et al. (1998). Effects of 50 Hz EMF exposure on micronucleus formation and apoptosis in transformed and nontransformed human cell lines. Bioelectromagnetics, 19(2): 85–91.
[17] Prevarskaya, N., et al. (2014). Remodelling of Ca2+ transport in cancer: How it contributes to cancer hallmarks? Philosophical Transactions of the Royal Society B: Biological Sciences, 369(1638): 20130097.
[18] Destefanis, M., et al. (2015). Extremely low frequency electromagnetic fields affect proliferation and mitochondrial activity of human cancer cell lines. International Journal of Radiation Biology, 91(12): 964–972.
[19] Lyle, D. B., et al. (1991). Calcium uptake by leukemic and normal T‐lymphocytes exposed to low frequency magnetic fields. Bioelectromagnetics, 12(3): 145–156.
[20] Tiwari, R., et al. (2015). Epinephrine, DNA integrity and oxidative stress in workers exposed to extremely low-frequency electromagnetic fields (ELF-EMFs) at 132 kV substations. Electromagnetic Biology and Medicine, 34(1): 56–62.
[21] Schwartz, J. L., House, D. E., & Mealing, G. A. (1990). Exposure of frog hearts to CW or amplitude‐modulated VHF fields: Selective efflux of calcium ions at 16 Hz. Bioelectromagnetics, 11(4), 349–358.
[22] Makinistian, L., Marková, E., & Belyaev, I. (2019). A high throughput screening system of coils for ELF magnetic fields experiments: Proof of concept on the proliferation of cancer cell lines. BMC Cancer, 19(1), 188.
[23] Nuccitelli, R., Tran, K., Sheikh, S., Athos, B., Kreis, M., & Nuccitelli, P. (2010). Optimized nanosecond pulsed electric field therapy can cause murine malignant melanomas to self‐destruct with a single treatment. International Journal of Cancer, 127(7), 1727–1736.
[24] Hu, J. H., St-Pierre, L. S., Buckner, C. A., Lafrenie, R. M., & Persinger, M. A. (2010). Growth of injected melanoma cells is suppressed by whole body exposure to specific spatial-temporal configurations of weak intensity magnetic fields. International Journal of Radiation Biology, 86(2), 79–88.
[25] Te-Wei Yeh (2016). Effects of Schumann Wave on B16F10 Cancer Cells, Master’s thesis, University of National Cheng Kung, Taiwan.
[26] Tang, J. Y., Yeh, T. W., Huang, Y. T., Wang, M. H., & Jang, L. S. (2019). Effects of extremely low-frequency electromagnetic fields on B16F10 cancer cells. Electromagnetic biology and medicine, 1-9.
[27] Buckner, C. A., Buckner, A. L., Koren, S. A., Persinger, M. A., & Lafrenie, R. M. (2017). The effects of electromagnetic fields on B16‐BL6 cells are dependent on their spatial and temporal character. Bioelectromagnetics, 38(3), 165–174.
[28] Martirosyan, V., Baghdasaryan, N., & Ayrapetyan, S. (2013). Bidirectional frequency-dependent effect of extremely low-frequency electromagnetic field on E. coli K-12. Electromagnetic Biology and Medicine, 32(3), 291–300.
[29] Nuccitelli, R., Tran, K., Sheikh, S., Athos, B., Kreis, M., & Nuccitelli, P. (2010). Optimized nanosecond pulsed electric field therapy can cause murine malignant melanomas to self‐destruct with a single treatment. International Journal of Cancer, 127(7), 1727-1736.
[30] Still, M., Lindström, E., Ekstrand, A. J., Mild, K. H., Mattsson, M. O., & Lundgren, E. (2002). Inability of 50 Hz magnetic fields to regulate PKC- and Ca2+-dependent gene expression in Jurkat cells. Cell Biology International, 26(2), 203–209.
[31] Wertheimer, N., & Leeper, E. D. (1979). Electrical wiring configurations and childhood cancer. American Journal of Epidemiology, 109(3), 273–284.
[32] Riss, T. L., Moravec, R. A., Niles, A. L., Duellman, S., Benink, H. A., Worzella, T. J., & Minor, L. (2016). Cell viability assays.
[33] Fernández-Ros, M., Parra, J. A. G., Salvador, R. M. G., & Castellano, N. N. (2016). Optimization of the periodogram average for the estimation of the power spectral density (PSD) of weak signals in the ELF band. Measurement, 78, 207–218.
[34] Wang, L. W., Zhao, J. L., Wang, Z. Y., & Pang, L. N. (2007). Application of zoom FFT technique to detecting EM signal of SLF/ELF. Acta Seismologica Sinica, 20(1), 63–70.
[35] Holmes, D. G., & Lipo, T. A. (2003). Pulse width modulation for power converters: principles and practice (Vol. 18). Australia, John Wiley & Sons Inc.
[36] Brigham, E. O. (1973). The fast fourier transform: An introduction to Its theory and application.
[37] Foletti, A., Ledda, M., De Carlo, F., Grimaldi, S., & Lisi, A. (2010). Calcium ion cyclotron resonance (ICR), 7.0 Hz, 9.2 μT magnetic field exposure initiates differentiation of pituitary corticotrope-derived AtT20 D16V cells.
Electromagnetic biology and medicine, 29(3), 63-71.