Effects of extremely low frequency electromagnetic field (ELF-EMF) on catalase, cytochrome P450 and nitric oxide synthase in erythro-leukemic cells
Patruno A, Tabrez S, Pesce M, Shakil S, Kamal MA, Reale M. Effects of extremely low frequency electromagnetic field (ELF-EMF) on catalase, cytochrome P450 and nitric oxide synthase in erythro-leukemic cells. Life Sci. 2014 Dec 11. pii: S0024-3205(14)00966-7. doi: 10.1016/j.lfs.2014.12.003. [Epub ahead of print]
AIMS: Extremely low frequency electromagnetic fields (ELF-EMFs) are widely employed in electrical appliances and different equipment such as television sets, mobile phones, computers and microwaves. The molecular mechanism through which ELF-EMFs can influence cellular behavior is still unclear. A hypothesis is that ELF-EMFs could interfere with chemical reactions involving free radical production. Under physiologic conditions, cells maintain redox balance through production of ROS/RNS and antioxidant molecules. The altered balance between ROS generation and elimination plays a critical role in a variety of pathologic conditions including neurodegenerative diseases, aging and cancer. Actually, there is a disagreement as to whether there is a causal or coincidental relationship between ELF-EMF exposure and leukemia development. Increased ROS levels have been observed in several hematopoietic malignancies including acute and chronic myeloid leukemias.
MAIN METHODS: In our study, the effect of ELF-EMF exposure on catalase, cytochrome P450 and inducible nitric oxide synthase activity and expression by Western blot analysis in myelogenous leukemia cell line K562 was evaluated.
KEY FINDINGS: A significant modulation of iNOS, CAT and Cyt P450 protein expression was recorded as a result of ELF-EMF exposure in both phorbol 12-myristate 13-acetate (PMA)-stimulated and non-stimulated cell lines. Modulation in kinetic parameters of CAT, CYP-450 and iNOS enzymes in response to ELF-EMF indicates an interaction between the ELF-EMF and the enzymological system.
SIGNIFICANCE: These new insights might be important in establishing a mechanistic framework at the molecular level within which the possible effects of ELF-EMF on health can be understood.
Despite the large number of studies performed, a causal relationship and biological mechanisms for potential effects of ELF-EMFs on carcinogenesis have not been clearly identified as yet. The main cause of skepticism is the ability of low amount of energy transfer by these fields to DNA . Moreover, epidemiological associations observed between ELF-EMFs and cancer are believed to be mainly due to promoter, co-promoter or progressor effects rather than initiator .
On the other hand, appropriately controlled application of ELF-EMFs have therapeutic applications as well. Low frequency and low intensity fields have been used extensively for the treatment of non-union fractures and can accelerate wound healing ,  and . Pain and spasticity reduction is another area in which pulsed electromagnetic therapy has been reported to be very effective  and .
Currently, very little is known about how ELF-EMF modifies the biological systems. It can initiate a number of biochemical and physiological alterations in biological systems of different species ,  and . The biological effects in cell lines exposed to ELF-EMFs have been frequently noted , , ,  and . However, despite the large number of studies, an understanding is still lacking ,  and . The time span of application is an important factor which governs the physiological response of cells towards ELF-EMF exposure. In our earlier study, we have reported that ELF-EMFs applied at different time lengths modulate chemokine production and keratinocyte growth via inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathway and might inhibit inflammatory processes . Another study reported that a single exposure to ELF-EMF results in a decrease in K562 differentiation, while continuous ELF-EMF exposure caused an increase in differentiation .
In this study, we used the K562 cell line, that are considered to be a reliable in vitro model of the hematopoietic system and of oxidative stress to assess the biological effects of ELF-EMF exposure. The purpose of this study was to evaluate activity and expression of catalase, cytochrome P450 and inducible nitric oxide synthase and their kinetic parameters in K562 cell line exposed to a well-defined and controlled ELF-EMF to add new knowledge about the mechanisms responsible for the biological effects of ELF-EMFs.
The experimental setup and ELF-EMF exposure system have been previously described by . Briefly, the oscillating magnetic field (AC MF) consisted of: 1) a generator of sinusoidal signal at 50 Hz; 2) a power amplifier; 3) an oscilloscope dedicated to monitoring output signals from the gaussmeter (MG-3D, Walker Scientific); 4) a 160 turn solenoid (22 cm in length, 6 cm in radius, copper wire diameter of 1.25 × 10− 5 cm) generating a horizontal magnetic field. The solenoid was then placed inside the incubator. The geomagnetic field and magnetic field generated by solenoid have the same orientation. The achieved MF intensity (1 mT (rms)) was measured continuously using the hall-effect probe, situated adjacent to the specimen located in the central part of the solenoid, and connected to the gaussmeter ...
ConclusionWe hypothesize that ELF-EMF could trigger protein activation mediated by ligands, such as Ca2 +, activating NADH oxidase that alter ROS-regulated pathways, particularly pro-proliferative and/or survival pathways. In addition, modulation of kinetic parameters of CAT, CYP-450 and iNOS enzymes in response to ELF-EMF indicate an interaction between ELF-EMF and enzymological system. Our results confirm that the ELF-EMF affects not only the ROS product but also the enzymatic activity. Taken together, these results demonstrate the interplay between ROS and antioxidant molecules influenced by ELF-magnetic fields and underscore the subtle effects of low-frequency magnetic fields on oxidative metabolism and ROS signaling, that may be particularly important in hematologic malignancies.
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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