The effects of irradiation (200kV X-ray, 5 Gy), extremely low frequency electromagnetic fields (ELF-EMF, 50 Hz, 60 ± 0.2 microT) and/or heat shock (HS, 41°C for 30 min) on the expression of several heat shock genes (HSP27, HSP60, HSP70, HSP75, HSP78, HSP90) in human HL-60 leukaemia cells was studied by RT-PCR. In addition, the effects of these stressors on cell cycle progression in exponentially and asynchronously growing cell cultures were studied by flow cytometry. The dynamics of cell division during successive cell cycles was monitored by fluorescence-labelling of the cells with carboxyfluorescein succinimidyl ester (CFSE). Finally, the cell cycle distribution was studied by staining with propidium iodide (PI). With respect to HSP gene expression the three stressors produced similar effects. The combination of stressors (ELF-EMF and HS or Radiation and HS) strongly induced transcription of the HSP70 gene above the level induced by each stressor alone. The cell cycle analysis, however, revealed striking differences in the cellular response to each stressor. Of particular interest was the observed thermoprotective effect of ELFEMF in heat shocked cells, an effect that was not seen in cells which were exposed to X-rays in the presence of thermal stress.
electromagnetic fields; heat shock; radiation; thermoprotection; X-rays
Biade S, Stobbe CC, Chapman JD: The intrinsic radiosensitivity of some human tumor cells throughout their cell cycles. Radiat Res 147:416-421, 1997.
Berg H: Problems of weak electromagnetic field effects in cell biology. Bioelectrochem Bioenerg 48:355-360, 1999.
Carmody S, Wu XL, Lin H, Blank M, Skopicki H, Goodman R: Cytoprotection by electromagnetic field-induced hsp70: a model for clinical application. J Cell Biochem 79:453-459, 2000.
Gabai VL, Yaglom JA, Voloch V, Merlin AB, Forse T, Koutroumanis M, Massie B, Mosser DD, Sherman M: Hsp72-mediated supression of c-Jun N-terminal kinase is imlicated in development of tolerance to caspase-independent cell death. Mol Cell Biol 20:6826-6836, 2000.
Goodman R, Blank M, Lin H, Khorkova O, Soo L, Weisbrot D, Henderson A: Increased level of hsp70 transcripts induced when cells are exposed to low frequency electromagnetic fields. Biochem Bioenerg 33:115-120, 1994.
Gutzeit HO: Interaction of stressors and the limits of cellular homeostasis. Biochem Biophys Res Commun 283:721-725, 2001.
Hang H, Fox MH: Levels of 70-kDa heat shock protein through the cell cycle in several mammalian cell lines. Cytometry 25:367-375, 1996.
Hasbold J, Gett AV, Rush JS, Deenick E, Avery D, Jun J, Hodgkin PD: Quantitative analysis of lymphocyte differentiation and proliferation in vitro using carboxyfluorescein diacetate succinimidyl ester. Immunol Cell Biol 77:516-522, 1999.
Jin M, Blank M, Goodman R: ERK1/2 phosphorylation, induced by electromagnetic fields, diminishes during neoplastic transformation. J Cell Biochem 78:371-379, 2000.
Junkersdorf B, Bauer H, Gutzeit HO: Electromagnetic fields enhance the stress response at elevated temperatures in the nematode Caenorhabditis elegans. Bioelectromagnetics 21:100-106, 2000.
Kirschvink JL: Uniform magnetic fields and double-wrapped coil systems: Improved techniques for the design of bioelectromagnetic experiments. Bioelectromagnetics 13:401-411, 1991.
Kuhl NM, Kunz J, Rensing L: Heat shock-induced arrests in different cell cycle phases of rat C6-glioma cells are attenuated in heat shock-primed thermotolerant cells. Cell Prolif 33:147-166, 2000.
Lin H, Blank M, Rossol-Haseroth K, Goodman R: Regulating genes with electromagnetic response elements. J Cell Biochem 81:143-148, 2001.
Lyons AB: Divided we stand: Tracking cell proliferation with carboxyfluorescein diacetate succinimidyl ester. Immunol Cell Biol 77:509-515, 1999.
Merritt R, Purcell C, Stroink G: Uniform magnetic field produced by three, four and five square coils. Rev Sci Instrum 54:879-882, 1983.
Michel A, Gutzeit HO: Electromagnetic fields in combination with elevated temperatures affect embryogenesis of Drosophila. Biochem Biophys Res Commun 265:73-78, 1999.
Nitta M, Okamura H, Aizawa S, Yamaizumi M: Heat shock induces transient p53-dependent cell cycle arrest at G1/S. Oncogene 15:561-568, 1997.
Read RA, Fox MH, Bedford JS: The cell cycle dependence of thermotolerance. I. CHO cells heated at 42 °C. Radiat Res 93:93-106, 1983.
Rice GC, Gray JW, Dean PN, Dewey WC: Fluorescence activated cell sorting analysis of the induction and expression of acute thermal tolerance within the cell cycle. Cancer Res 44:2368-2376, 1984.
Ritossa FA: New puffing pattern induced by temperature shock and DNP in Drosophila. Experientia 18:571-573, 1962.
Sinclair WK: Cyclic X-ray responses in mammalian cells in vitro. Radiat Res 33:620-643, 1968.
Tang H, Davis MA, Strickfaden SM, Maybaum J, Lawrence TS: Infuence of cell cycle phase on radiation-induced cytotoxicity and DNA damage in human colon cancer (HT29) and Chinese hamster ovary cells. Radiat Res 138:109-112, 1994.
Tokalov SV: The analysis of postradiative cytodynamic of normal and tumour tissues by flow cytometry (In Rus). PhD thesis., Leningrad 1990, pp 20.
Tokalov SV, Gutzeit HO: The heat shockinduced cell cycle arrest is attenuated by weak electromagnetic fields. Cell Prolif, in press, 2003a.
Tokalov SV, Gutzeit HO: Weak electromagnetic fields (50 Hz) elicit a stress response in human cells. Environm Res, in press, 2003b.
Zolzer F, Streffer C: Quiescence in S-phase and G1 arrest induced by irradiation and/or hyperthermia in six human tumour cell lines of different p53 status. Int J Radiat Biol 76:717-725, 2000.
Garip AI, Akan Z: Effect of ELF-EMF on number of apoptotic cels; correlation with reactive oxygen species and HSP. Acta Biolog Hungarica 61:158-167, 2010.
Bellizzi D, Taverna D, D'Aquila P, De Blasi S, De Benedictis G: Mitochondrial DNA variability modulates mRNA and intra-mitochondrial protein levels of HSP60 and HSP75: experimental evidence from cybrid lines. Cell Stress Chaperones 14:265-271, 2009.
Tokalov SV, Pieck S, Gutzeit HO: Varying responses of human cells with discrepant p53 activity to ionizing radiation and heat shock exposure. Cell Proliferation 40:24-37, 2007.
Silagadze ZK: Tunguska genetic anomaly and electrophonic meteors. Acta Phys Pol B 36:935-964, 2005.
Nitzsche A, Tokalov SV, Gutzeit HO, Ludwig-Muller J: Chemical and biological characterization of cinnamic acid derivatives from cell cultures of lavender (Lavandula officinalis) induced by stress and jasmonic acid. J Agric Food Chem 52:2915-2923, 2004.
Tokalov SV, Kind B, Wollenweber E, Gutzeit HO: Biological effects of epicuticular flavonoids from Primula denticulata on human leukemia cells. J Agric Food Chem 52:239-245, 2004.