J Cancer Sci Clin Ther 2021; 5 (1): 094-105 DOI: 10.26502/jcsct.50790103 Journal of Cancer Science and Clinical Therapeutics 94 Research Article Extremely Low Frequency Magnetic Fields Increase the Expression of HIF-1 in Prostate Cancer Cells Sharon Amir 1 , Snir Dekalo 1,2 , Joseph Friedman 3 , Nicola J Mabjeesh 1,4* 1 Prostate Cancer Research Laboratory, Tel Aviv Medical Center, Tel Aviv, Israel 2 Department of Urology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 3 Department of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel 4 Department of Urology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel * Corresponding Authors: Dr. Nicola J Mabjeesh, Department of Urology, Soroka University Medical Center, Beer-Sheva, POB 151, Israel, E-mail: mabjeesh@bgu.ac.il Received: 01 December 2020; Accepted: 30 December 2020; Published: 19 January 2021 Citation: Sharon Amir, Snir Dekalo, Joseph Friedman, Nicola J Mabjeesh. Extremely Low Frequency Magnetic Fields Increase the Expression Of HIF-1 in Prostate Cancer Cells. Journal of Cancer Science and Clinical Therapeutics 5 (2021): 094-105. Abstract Background: Increased levels of hypoxia-inducible factor 1 (HIF-1) are related to poor prognosis and treatment failure in prostate cancer. The effect of extremely low frequency magnetic fields (ELF-MF), generally emitted from electronic devices on HIF-1 in cancer cells and, specifically, in prostate cancer is not well described. This study aimed to investigate the effects of ELF-MF on HIF- 1 protein expression and HIF-1 transcriptional activity in prostate cancer cells. Methods: Prostate cancer cells were irradiated with ELF- MF by means of a frequency generator at 875 MHz with an intensity of 0.07 mW/cm 2 at various time periods and with an exposure system housed in a tissue culture incubator. The expression of HIF-1 protein and HIF-1 transcriptional activity at the different conditions were evaluated. Results: HIF-1 expression in different prostate cancer cells was higher after one hour of exposure to ELF-MF. All exposed cells also demonstrated a significant 50% increase in HIF-1 transcriptional activity as measured by an HRE- dependent reporter gene assay after ELF-MF irradiation. Cells exposed to ELF-MF exhibited 3-fold longer HIF-1 half-life compared to non-exposed control cells, while its mRNA levels were not affected. Immunofluorescence