Expression of HSP72 after ELF‐EMF exposure in three cell lines

Abstract

It has been reported that magnetic fields with flux densities ranging from microT to mT are able to induce heat shock factor, HSP72 mRNA or heat shock proteins in various cells. In this study we investigated changes in the HSP72 mRNA transcription level in three cell lines (HL-60, H9c2, and Girardi heart cells) and in the intracellular HSP72 protein content in two cell lines (HL-60 and Girardi heart cells) after treatment schemes using electromagnetic fields with a flux density of 2 microT to 4 mT, a frequency of 50 Hz and exposure times from 15 to 30 min. None of the treatments or modalities showed any significant effect on the HSP72 protein level, although HSP72 mRNA could be induced, at least to some extent, with one of the parameter combinations in all cell lines tested. Obviously, HSP72 mRNA transcription and translation are not necessarily coupled in certain cells. This leads to the conclusion that electromagnetic field effects on HSP72 mRNA levels are not indicative for downstream effects unless increased mRNA levels can be correlated with increased HSP72 protein levels as well.

Effect of Extremely Low Frequency Magnetic Fields on Gene Expression in Human Mammary Epithelial MCF10A Cells

“…Using high-throughput analysis, we found that genome-wide expression levels in MCF10A human breast epithelial cells were not changed by exposure to ELF-MFs. To confirm these results, we performed sqRT-PCR on six genes selected from the microarray analysis that exhibited statistically non-significant trends for expression changes; the follow-up results confirmed those of the Previous studies reported that ELF-MF exposure could affect transcription levels in vitro of several immediate-response genes [8], [19]～ [21]. These studies, however, only looked at a few genes and their results require further confirmation before firm conclusions can be drawn.…”

“…Martínez et al reported that ELF-MF could stimulate proliferative activity in neuronal cells by triggering MAPK-ERK1/2 signaling [7]. It has been also reported that electromagnetic fields (EMF) transiently influence the transcript level of genes related to apoptosis and the cell cycle [8], [9]. However, in vitro studies failed to demonstrate any biological effects of ELF-MFs [10]～ [13].…”

Extremely low‐frequency electromagnetic fields affect the immune response of monocyte‐derived macrophages to pathogens

“…On the other hand, they suggested that short-term exposure may be beneficial since it induced protection during subsequent hypoxia or UV radiation. Gottwald et al [2007] observed that 1 mT field exposure for 15 min resulted in an increase in HSP72 mRNA, but the hsp70 protein level did not increase. They argued that transcriptional activation of HSP72 gene is independent of protein synthesis.…”

Molecular basis underlying the biological effects elicited by extremely low-frequency magnetic field (ELF-MF) on neuroblastoma cells

“…Several studies suggested that there is a possible association between ELF-MFs and malignancies in childhood and adulthood such as leukemia and nervous system tumors as well as cardiovascular and neurological disorders [Wertheimer and Leeper, 1979;IARC, 2002;Håkansson et al, 2003;Draper et al, 2005;Davanipour et al, 2007]. A number of in vivo and in vitro investigations have shown a possible co-promoter capacity of ELF-MFs on tumor growth as well as the potential effects elicited by ELF-MFs on various cellular functions [Crumpton and Collins, 2004;Simkó , 2004;Santini et al, 2005;Wolf et al, 2005;Berg and Berg, 2006;Frahm et al, 2006;Lisi et al, 2006;Palumbo et al, 2006;Gottwald et al, 2007]. Unfortunately, the biological mechanisms by which these physical agents can be involved in a possible tumor-promoting or tumor-initiating action are still unclear.…”