Medical/biological study (experimental study)

Mitochondrial hyperpolarization and cytochrome-c release in microwave-exposed MCF-7 cells med./bio.

By: Esmekaya MA, Canseven AG, Kayhan H, Tuysuz MZ, Sirav B, Seyhan N

Published in: Gen Physiol Biophys 2017; 36: 211-218

Aim of study (acc. to author)

The effects of exposure of breast cancer cells to a 2.1 GHz electromagnetic field on apoptosis and the underlying mechanisms of action should be investigated.

Background/further details

Cells were divided into the following groups: 1) exposure to the electromagnetic field for 4 hours, 2) exposure to the electromagnetic field for 24 hours. For each exposure group, a separate sham exposure group was used.

Endpoint

cell viability/cell division/proliferation: apoptosis and underlying mechanisms of action

Exposure

- 2.1 GHz
- RF
- microwaves
- W-CDMA
- mobile communications
- mobile phone

Exposure	Parameters
Exposure 1: 2.1 GHz Exposure duration: continuous for 4 or 24 hours	SAR: 0.528 W/kg peak value (10 g) power density: 0.12 mW/cm² (inside the incubator)

Exposure 1

Main characteristics

Frequency	2.1 GHz
Type	electromagnetic field
Exposure duration	continuous for 4 or 24 hours

Exposure setup

Exposure source	horn antenna
Chamber	incubator (37°C)
Setup	cells were cultivated in plates with 24 wells and placed above the antenna, which was connected to a signal generator, inside the incubator
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.528 W/kg	peak value	calculated	10 g	-
power density	0.12 mW/cm²	-	measured	-	inside the incubator

Additional parameter details

ambient magnetic field had a magnetic flux density of 0.146 µT

Exposed system:

intact cell/cell culture
MCF-7 cells (human breast cancer cell line)

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: cell viability (MTT assay), apoptosis (annexin V/FITC stain (early apoptosis), propidium iodide stain (necrosis), fluorescence microscopy and flow cytometry)
molecular biosynthesis: level of p53 and cytochrome c (markers for apoptosis pathways, ELISA)
cell function: mitochondrial membrane potential (JC-1 stain, flow cytometry)

Investigated system:

intact cell/cell culture
isolated bio./chem. substance
cell extract

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Cells exposed to the electromagnetic field for 4 hours (group 1) or 24 hours (group 2) showed a significantly decreased cell viability compared to sham exposed cells. The percentage of apoptotic cells, level of cytochrome-c and the mitochondrial membrane potential were significantly higher in exposed cells (groups 1 and 2) compared to sham exposed cells. (Remark EMF-Portal: according to the abstract, cell viability was also significantly lower after longer exposure and the percentage of apoptotic cells and the mitochondrial membrane potential were significantly higher in cells exposed for 24 hours compared to cells exposed for 4 hours. However, this is not mentioned in the results section or figures.)
p53 levels did not show any changes.
The authors conclude that exposure of breast cancer cells to a 2.1 GHz electromagnetic field might cause hyperpolarization of mitochondria which in turn could induce apoptosis.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Gazi University Research Foundation, Turkey

Hou Q et al. (2015): Oxidative changes and apoptosis induced by 1800-MHz electromagnetic radiation in NIH/3T3 cells
Canseven AG et al. (2015): Effects of microwave exposure and Gemcitabine treatment on apoptotic activity in Burkitt's lymphoma (Raji) cells
Esmekaya MA et al. (2013): Investigation of the effects of 2.1 GHz microwave radiation on mitochondrial membrane potential (DeltaPsim), apoptotic activity and cell viability in human breast fibroblast cells
Liu YX et al. (2012): Exposure to 1950-MHz TD-SCDMA Electromagnetic Fields Affects the Apoptosis of Astrocytes via Caspase-3-Dependent Pathway
Joubert V et al. (2008): Apoptosis is Induced by Radiofrequency Fields through the Caspase-Independent Mitochondrial Pathway in Cortical Neurons
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Lantow M et al. (2006): Comparative study of cell cycle kinetics and induction of apoptosis or necrosis after exposure of human mono mac 6 cells to radiofrequency radiation
Caraglia M et al. (2005): Electromagnetic fields at mobile phone frequency induce apoptosis and inactivation of the multi-chaperone complex in human epidermoid cancer cells
Nikolova T et al. (2005): Electromagnetic fields affect transcript levels of apoptosis-related genes in embryonic stem cell-derived neural progenitor cells
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