Medical/biological study (experimental study)

Effect of 60 Hz electromagnetic fields on the activity of hsp70 promoter: An in vitro study med./bio.

By: Rodriguez de la Fuente AO, Alcocer-Gonzalez JM, Heredia-Rojas JA, Balderas-Candanosa I, Rodriguez-Flores LE, Rodriguez-Padilla C, Tamez-Guerra RS

Published in: Cell Biol Int 2009; 33 (3): 419-423

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Aim of study (acc. to author)

To study the effect of 60 Hz electromagnetic field on the activity of hsp70 promoter in cells transfected with the luciferase gene as reporter gene.

Background/further details

The combined effect of extremely low frequency magnetic field and thermal shock (43°C, 20 min.) was also evaluated in the HeLa cell line (co-exposure).

Endpoint

molecular biosynthesis: activity of hsp70 promoter: gene expression of luciferase gene

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 20 min	magnetic flux density: 8 µT effective value magnetic flux density: 80 µT effective value

General information

cells were treated in four groups: i) exposure to EMF ii) thermal shock iii) exposure to EMF + thermal shock iv) sham exposure

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 20 min

Exposure setup

Exposure source	solenoid
Setup	25 cm long solenoid with a radius of 5.27 cm and 340 turns of 1.3 mm enamel insulated copper wire; solenoid placed inside an incubator; cultures positioned in the middle of the solenoid where the MF was homogenous
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	8 µT	effective value	measured	-	-
magnetic flux density	80 µT	effective value	measured	-	-

Additional parameter details

average geomagnetic field in the exposure room: 20 µT

Exposed system:

intact cell/cell culture
HeLa cell line (human adenocarcinoma cell line) and BMK16 (Baby Mouse Kidney cells), transfected with the plasmid pEMF (electromagnetic field plasmid containing hsp70 promotor and the luciferase gene as reporter gene)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: activity of hsp70 promoter: gene expression of luciferase gene (luciferase enzyme activity)

Investigated system:

cell lysates

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data showed that the 60 Hz magnetic field was able to increase the luciferase gene expression in both cell lines transfected with the hsp70 promoter. The gene expression levels of the magnetic field exposed cells were higher compared to the other groups. A synergistic effect of the applied fields and the heat shock was found in the HeLa cells (16-fold increase compared to heat shock alone).

Study character:

medical/biological study
experimental study
full/main study
replication/reproduction study
Short Communication

Study funded by

Consejo Nacional de Ciencia y Tecnología (CONACyT; National Council for Science and Technology), Mexico
Programa de Apoyo a la Investigación Científica y Tecnológica (PAICYT), Universidad Autonoma de Nuevo Leon (UANL), Mexico

Replicated studies

Lin H et al. (2001): Regulating genes with electromagnetic response elements

Rodriguez-De la Fuente AO et al. (2012): Effect of 60 Hz electromagnetic fields on the activity of hsp70 promoter: an in vivo study
Heredia-Rojas JA et al. (2010): Effect of 60 Hz magnetic fields on the activation of hsp70 promoter in cultured INER-37 and RMA E7 cells
Mannerling AC et al. (2010): Effects of 50-Hz magnetic field exposure on superoxide radical anion formation and HSP70 induction in human K562 cells
Bernardini C et al. (2007): Effects of 50 Hz sinusoidal magnetic fields on Hsp27, Hsp70, Hsp90 expression in porcine aortic endothelial cells (PAEC)
Gottwald E et al. (2007): Expression of HSP72 after ELF-EMF exposure in three cell lines
Alfieri RR et al. (2006): Increased levels of inducible HSP70 in cells exposed to electromagnetic fields
Coulton LA et al. (2004): Effect of 50 Hz electromagnetic fields on the induction of heat-shock protein gene expression in human leukocytes
Tokalov SV et al. (2004): Weak electromagnetic fields (50 Hz) elicit a stress response in human cells
Henderson BR et al. (2003): Expression levels of heat shock protein 60 in human endothelial cells in vitro are unaffected by exposure to 50 Hz magnetic fields
Lin H et al. (2001): Regulating genes with electromagnetic response elements
Morehouse CA et al. (2000): Exposure to low-frequency electromagnetic fields does not alter HSP70 expression or HSF-HSE binding in HL60 cells
Pipkin JL et al. (1999): Induction of stress proteins by electromagnetic fields in cultured HL-60 cells
Kang KI et al. (1998): Luciferase activity and synthesis of Hsp70 and Hsp90 are insensitive to 50Hz electromagnetic fields
Goodman R et al. (1998): Magnetic field stress induces expression of hsp70