Medical/biological study (experimental study)

Possible attenuation of the G2 DNA damage cell cycle checkpoint in HeLa cells by extremely low frequency (ELF) electromagnetic fields med./bio.

By: Harris PA, Lamb J, Heaton B, Wheatley DN

Published in: Cancer Cell Int 2002; 2: 3

Aim of study (acc. to author)

To investigate the effects on cell cycle regulation in human cervical carcinoma cells exposed to extremely low frequency electromagnetic field and/or gamma radiation (1, 3, and 5 Gy) in vitro.

Background/further details

Cellular DNA damage can be recognized and cell cycle stopped by so called "DNA damage cell cycle checkpoints". The examined cell line affords analysing G₂ phase checkpoint. The G₂ phase checkpoint stops cells entering mitosis with damaged chromosomes. Loss of checkpoint control is a feature of oncogenic transformation.

Endpoint

cell viability/cell division/proliferation: cell cycle

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: not specified in this article	magnetic flux density: 2 mT effective value

General information

Cells were subjected to the following conditions at 37°C in a 5% CO₂/air atmosphere: Group 1: control group, Group 2: no irradiation but exposed to MF, Group 3: irradiated with (137)CS at 1-5 Gy and no EMF exposure, Group 4: irradiated with (137)CS at 1-5 Gy and exposed to MF.

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	not specified in this article

Exposure setup

Exposure source	Helmholtz coils
Setup	MF perpendicular to the cell monolayers.
Sham exposure	A sham exposure was conducted.
Additional info	The exposure system was housed in a 37°C hot room.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	2 mT	effective value	measured	-	-

Exposed system:

intact cell/cell culture
HeLa S3 (human cervical carcinoma cell line)

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: cell cycle phase (number of cells in different cell stages), DNA content (propidium iodide staining, flow cytometry)

Investigated system:

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

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Cells exposed to extremely low frequency electromagnetic field alone had no effect on their progression into cell division compared to control group. Cells exposed to gamma radiation alone slowly regained their ability to enter and complete mitosis, but were considerably delayed compared to control group and electromagnetic field exposed group. Co-exposed cells (electromagnetic field and gamma radiation) similary showed a considerable delay in progressing through mitosis. However, co-exposed cells were entering G₁ phase earlier than cells only exposed to gamma radiation, which would be consistent with a reduced G₂ phase checkpoint control. This effect was more prominent with increasing doses of gamma radiation.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Jin H et al. (2015): Effects on G2/M phase cell cycle distribution and aneuploidy formation of exposure to a 60 Hz electromagnetic field in combination with ionizing radiation or hydrogen peroxide in L132 nontumorigenic human lung epithelial cells
Buldak RJ et al. (2012): Short-term exposure to 50 Hz ELF-EMF alters the cisplatin-induced oxidative response in AT478 murine squamous cell carcinoma cells
Sul AR et al. (2006): Effects of sinusoidal electromagnetic field on structure and function of different kinds of cell lines
Huang L et al. (2006): Effects of sinusoidal magnetic field observed on cell proliferation, ion concentration, and osmolarity in two human cancer cell lines
Williams PA et al. (2006): 14.6 mT ELF magnetic field exposure yields no DNA breaks in model system Salmonella, but provides evidence of heat stress protection
Wolf FI et al. (2005): 50-Hz extremely low frequency electromagnetic fields enhance cell proliferation and DNA damage: possible involvement of a redox mechanism
Cucullo L et al. (2005): Very low intensity alternating current decreases cell proliferation
Lange S et al. (2004): Modifications in cell cycle kinetics and in expression of G1 phase-regulating proteins in human amniotic cells after exposure to electromagnetic fields and ionizing radiation
Tokalov SV et al. (2003): Comparison of the reactions to stress produced by X-rays or electromagnetic fields (50Hz) and heat: induction of heat shock genes and cell cycle effects in human cells
Tokalov SV et al. (2003): The heat shock-induced cell cycle arrest is attenuated by weak electromagnetic fields
Lange S et al. (2002): Alterations in the cell cycle and in the protein level of cyclin D1, p21CIP1, and p16INK4a after exposure to 50 Hz MF in human cells
Yoshizawa H et al. (2002): No effect of extremely low-frequency magnetic field observed on cell growth or initial response of cell proliferation in human cancer cell lines
Richard D et al. (2002): Influence of 50 Hz electromagnetic fields in combination with a tumour promoting phorbol ester on protein kinase C and cell cycle in human cells
Tian F et al. (2002): Exposure to Power Frequency Magnetic Fields Suppresses X-Ray-Induced Apoptosis Transiently in Ku80-Deficient xrs5 Cells
Loberg LI et al. (2000): Cell viability and growth in a battery of human breast cancer cell lines exposed to 60 Hz magnetic fields
Hintenlang DE (1993): Synergistic effects of ionizing radiation and 60 Hz magnetic fields
Rosenthal M et al. (1989): Effects of 50 Hertz electromagnetic fields on proliferation and on chromosomal alterations in human peripheral lymphocytes untreated or pretreated with chemical mutagens