Investigation of the effects of distance from sources on apoptosis, oxidative stress and cytosolic calcium accumulation via TRPV1 channels induced by mobile phones and Wi-Fi in breast cancer cells
Bilal Çiğ, Mustafa Nazıroğlu. Investigation of the effects of distance from sources on apoptosis, oxidative stress and cytosolic calcium accumulation via TRPV1 channels induced by mobile phones and Wi-Fi in breast cancer cells. Biochimica et Biophysica Acta (BBA) - Biomembranes. Available online February 19, 2015.
AbstractTRPV1 is a Ca2 + permeable channel and gated by noxious heat, oxidative stress and capsaicin (CAP). Some reports have indicated that non-ionized electromagnetic radiation (EMR)-induces heat and oxidative stress effects. We aimed to investigate the effects of distance from sources on calcium signaling, cytosolic ROS production, cell viability, apoptosis, plus caspase-3 and -9 values induced by mobile phones and Wi-Fi in breast cancer cells
MCF-7 human breast cancer cell lines were divided into A, B, C and D groups as control, 900, 1800 and 2450 MHz groups, respectively. Cells in Group A were used as control and were kept in cell culture conditions without EMR exposure. Groups B, C and D were exposed to the EMR frequencies at different distances (0 cm, 1 cm, 5 cm, 10 cm, 20 cm and 25 cm) for one hour before CAP stimulation. The cytosolic ROS production, Ca2 + concentrations, apoptosis, caspase-3 and caspase-9 values were higher in groups B, C and D than in A group at 0 cm, 1 cm and 5 cm distances although cell viability (MTT) values were increased by the distances. There was no statistically significant difference in the values between control, 20 and 25 cm.
Wi-Fi and mobile phone EMR placed within 10 cm of the cells induced excessive oxidative responses and apoptosis via TRPV1-induced cytosolic Ca2 + accumulation in the cancer cells. Using cell phones and Wi-Fi sources which are farther away than 10 cm may provide useful protection against oxidative stress, apoptosis and overload of intracellular Ca2 +. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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- • Oxidative stress and Ca2 + influx play important role in functions of cancer cells.
- • Effects of EMR with different distances on Ca2 + and apoptosis were investigated.
- • EMR induced Ca2 + entry through TRPV1 channel in the breast cancer cells.
- • Distances 10 cm and up reduced EMR-induced apoptosis and Ca2 + influx in the cancer cells.
- • The study is the first to compare effects of distance on TRP channels in the cancer cells.
... Recently, we observed proliferative and tissue injury effects of exposure to 2450 MHz radiation in an HL-60 cancer cell line , an MDA-MB-231 breast cancer cell line  and in rat tissues through induction of Ca2+ influx and oxidative stress [4,13,30].
... The present study was designed to determine the effects of 900, 1800 and 2450 MHz EMR exposure on oxidative damage of breast cancer cells, apoptosis and ROS production, as well as the possible protective effects of different distances on the values by analyzing apoptosis, caspase activities, cytosolic ROS production, and accumulation of [Ca2+]i concentration-induced oxidative stress.
All the exposures at the different distances were repeated 4-6 times...
The continuous wave of radiofrequency signal (900 MHz with 217 Hz pulses) emitted by the generator was amplified initially and then fed into the cancer cells in the water bath by an antenna ...
... The required power density (≤ 12 uW/cm2) was continuously recorded every 5 min ... At the top of the flask, the average specific absorption rate (SAR) estimated for 900 MHz exposure at 12 uW/cm2 power flux density was 0.36 ± 0.02 mW/ kg (Table 1).
The use of mobile phones and Wi-Fi internet is currently one of the fastest growing technology developments. The likelihood of close proximity of the antenna of such a devices to the breast has raised concern about a possible biological connection between EMR and breast cancer of women [13,27,14]. The exposure to such radiation depends on the length of time and frequency of use, which varies from individual to individual. The most investigated RF waveforms of the GSM-modulated signals are at 900 MHz and 1800 MHz and the Wi-Fi (2450 MHz) signals. The EMR studies have been carried out on different cancer cell types such as HL-60 cancer cell line , an MDA-MB-231 breast cancer cell line . Modern cell phone devices and Wi-Fi internet in Turkey and many other countries work at a frequency of 900 MHz, 1800 MHz and 2450 MHz which were consequently
selected for the present study.
In the present study, the cytosolic ROS production, apoptosis, caspase-3 and caspase 9 values in the breast cancer cells increased after 900 MHz, 1800 MHz and 2450 MHz exposure. These data are in agreement with reports suggesting that EMR induces oxidative stress and apoptosis of cancer cells by inducing ROS [14,27,31]. We have shown also that the changes induced by EMR are very dependent on the distance from the source in the cancer cells. To our knowledge, it is the first report of the relationship between different distances and 900 MHz, 1800 MHz and 2450 MHz EMR in the MCF-7 breast cancer cells.
In the current breast cancer cells, apoptosis, caspase-3 and caspase-9 values were increased by 900 MHz, 1800 MHz and 2450 MHz in cells positioned within 10 cm of the EMR source. It is likely that TRPV1-mediated Ca2+ entry in the EMR-exposed breast cancer cell involves accumulation of ROS and opening of mitochondrial membrane pores that consequently leads to mitochondrial dysfunction, substantial swelling of the mitochondria with rupture of the outer membrane and release of apoptosis-inducing factors such as caspase 3 and caspase 9.
In conclusion, the current results demonstrate that 900 MHz, 1800 MHz and 2450 MHz radiations of mobile phones and Wi-Fi internet in breast cancer cells induce apoptosis and ROS through calcium accumulation of activation of TRPV1 channels. However, the increases of apoptosis and oxidative stress are modulated by different distances. We did not detect oxidative and apoptotic damage of breast cancer cells distanced 20 cm and 25 cm from the source of radiation. Using the cell phones and Wi-Fi radiation sources which are far from 10 cm may provide useful distance against oxidative stress, apoptosis and overload Ca2+ entry in cancer. In addition, we suggest that use of TRPV1 channel blockers may provide a potential therapeutic approach for the mobile phone and Wi-Fi-induced oxidative stress and apoptosis by calcium accumulation.
Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley
Electromagnetic Radiation Safety
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