Quantitative study of calcium uptake by tumorigenic bone (TE-85) and neuroblastoma x glioma (NG108-15) cells exposed to extremely-low-frequency (ELF) electric fields

FEBS Lett. 1997 Sep 8;414(2):343-8. doi: 10.1016/s0014-5793(97)01029-6.

Abstract

To verify the effect of cell culture state on frequency dependent increase in proliferation as well as Ca2+ flux across the plasma membrane, tumorigenic bone (TE-85) and neuroblastoma x glioma (NG108-15) cells cultured in the presence of fetal bovine serum (FBS) were exposed to capacitively coupled electric (CCEF) fields in the extremely low frequency (ELF) range of 10 to 18 Hz. [3H]Thymidine incorporation and 45Ca2+ uptake were used as endpoints. TE-85 cells cultured in the presence of 10% FBS did not exhibit a frequency dependent increase in proliferation in contrast to previous studies under growth arrested culture conditions, in which the cells were deprived of FBS. However, both TE-85 and NG108-15 cells had an increase in 45Ca2+ uptake in response to a 16 Hz 18.3 mV/cm CCEF. Fura-2 digital imaging microscopy was used to verify addition of 0.5 mM La3+ and 0.5 mM ionomycin as negative and positive controls, respectively. Imaging microscopy data was combined with 45Ca2+ incorporation results to quantify free intracellular calcium ([Ca2+]i) increase in response to CCEF exposure. TE-85 [Ca2+]i increased from 140 to 189-210 nM where as NG108-15 [Ca2+]i increased from 67 to 189-210 nM. These results suggested that serum deprivation may be a requirement for a frequency dependent increase in proliferation in TE-85 cells but is not necessary for the electric field induced increase in 45Ca2+ uptake in both TE-85 and NG108 cells. The present study also represents the first demonstration of increased 45Ca2+ uptake by neuroblastoma and/or glioma cells in response to an electric field exposure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport
  • Bone Neoplasms
  • Calcium / metabolism*
  • Cattle
  • Cell Division / drug effects
  • Cell Division / radiation effects
  • DNA, Neoplasm / biosynthesis*
  • Electricity*
  • Glioma
  • Humans
  • Hybrid Cells
  • Ionomycin / pharmacology
  • Kinetics
  • Lanthanum / pharmacology
  • Neuroblastoma
  • Oscillometry
  • Osteosarcoma
  • Thymidine / metabolism
  • Tumor Cells, Cultured

Substances

  • DNA, Neoplasm
  • Ionomycin
  • Lanthanum
  • Calcium
  • Thymidine