title: Real-time measurement of cytosolic free calcium concentration in Jurkat cells during ELF magnetic field exposure and evaluation of the role of cell cycle.
abstract: Extremely low frequency magnetic fields (ELF MF) have been reported to alter a number of cell signaling pathways, including those involved in proliferation, differentiation and apoptosis where cytosolic free calcium ([Ca(2+)](c)) plays an important role. To better understand the biological conditions under which ELF MF exposure might alter [Ca(2+)](c), we measured [Ca(2+)](c) by ratiometric fluorescence spectrophotometry during exposure to ELF MF in Jurkat E6.1 cells synchronized to different phases of the cell cycle. Suspensions of cells were exposed either to a near zero MF (Null) or a 60 Hz, 100 microT sinusoidal MF superimposed upon a collinear 78.1 microT static MF (AC + DC). An initial series of experiments indicated that the maximum increase in [Ca(2+)](c) above baseline after stimulation with anti-CD3 was significantly higher in samples exposed to AC + DC (n = 30) compared to Null (n = 30) with the largest difference in G2-M enriched samples. However, in a second study with G2-M enriched cells, samples treated with AC + DC (n = 17) were not statistically different from Null-treated samples (n = 27). Detailed analysis revealed that the dynamics in [Ca(2+)](c) before and after stimulation with anti-CD3 were dissimilar between Null samples from each study. From the results, we concluded (i) that the ELF MF increased [Ca(2+)](c) during an antibody-induced signaling event, (ii) that the ELF MF effect did not depend to a large degree on cell cycle, and (iii) that a field-related change in [Ca(2+)](c) signaling appeared to correlate with features in the [Ca(2+)](c) dynamics. Future work could evaluate [Ca(2+)](c) dynamics in relation to the phase of the cell cycle and inter-study variation, which may reveal factors important for the observation of real-time effects of ELF MF on [Ca(2+)](c).
authors.affiliation: Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Cheryl R
authors.initials: CR
authors.lastname: McCreary
authors.forename: S Jeffrey
authors.initials: SJ
authors.lastname: Dixon
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: Fraher
authors.forename: Jeffrey J L
authors.initials: JJ
authors.lastname: Carson
authors.forename: Frank S
authors.initials: FS
authors.lastname: Prato
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002453:Cell Cycle; D003600:Cytosol / Q000378:metabolism / Q000528:radiation effects*; D004247:DNA / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D019169:Jurkat Cells; D011874:Radiometry; D013050:Spectrometry, Fluorescence
chemical_list: D004247:DNA; D002118:Calcium