Exposure to low-frequency electromagnetic fields does not alter HSP70 expression or HSF-HSE binding in HL60 cells

Environmental exposure to extremely low-frequency electromagnetic fields (ELF EMFs) has been identified as a possible contributor to increased cancer incidence and other diseases. In vitro studies designed to probe for biological mechanisms that might explain such relationships have included several studies of gene expression. While gene expression studies have focused on MYC, effects of ELF EMFs on the expression of beta-actin, histone H2B, beta-tubulin, SRC, FOS and JUN have also been reported. In addition, some investigators have reported both an induction of HSP70 expression and an increase in HSF-HSE binding in HL60 (human promyelocytic leukemia) cells after exposure to a 60 Hz magnetic field. In this study, HL60 cells were exposed to a weak 60 Hz magnetic field (6.3 or 8.0 microT) or to a positive control heat shock (42 or 44 degrees C). While heat shock led to reproducible induction of HSP70 expression and HSF-HSE binding, no significant effect of exposure to ELF EMFs on either of these end points was observed.