Effect of Pulse-Modulated GSM-900 MHz Electromagnetic Field on the Electrochemotherapy Efficacy of 4T-1 Cells

Electrochemotherapy (ECT) is a cancer treatment modality to permeabilize cell membrane facilitating the non-permeant molecules to gain access to the cytosol of cells. Nevertheless, environmental electromagnetic fields (EMFs) may disturb the efficiency of ECT. The present study aimed to investigate the effect of EMFs 900 MHz pulse-modulated by 217 Hz extremely low-frequency fields on the efficiency of ECT The 4T-1 cells were exposed to 900 MHz radiofrequency (RF) modulated by 217 Hz fields at the power densities of 17, 162, and 349 µW/cm2 (related to antenna input powers of 3, 4, and 5 W at a distance of 15 cm) by a GSM900 MHz simulator. After exposure, the cells were divided into several groups, receiving no treatment, chemotherapy, electric pulse, and ECT. The cell viability was evaluated by MTT assay after 24 h. The results demonstrated that 900 MHz RF pulse-modulated by 217 Hz EMF at 349 µW/cm2 increased the viability of the cells treated with EPs with the amplitude of 70 V/cm and frequency of 5 kHz (16%), ECT with 70 V/cm at 5 kHz (20%), and ECT with 60 V/cm at 5 kHz (16%), compared to their counterpart treatment group with no exposure. However, the fields had no significant effect on the efficacy of chemotherapy. As the findings of the current study indicated, environmental pulsed-modulated RF fields exerted an adverse influence on some antitumor therapies. Therefore, such effects should be taken into consideration in determining the optimal protocols of treatment.