Comparison of fluorescence probes for intracellular sodium imaging in prostate cancer cell lines

Eur Biophys J. 2016 Oct;45(7):765-777. doi: 10.1007/s00249-016-1173-7. Epub 2016 Sep 22.


Sodium (Na+) ions are known to regulate many signaling pathways involved in both physiological and pathological conditions. In particular, alterations in intracellular concentrations of Na+ and corresponding changes in membrane potential are known to be major actors of cancer progression to metastatic phenotype. Though the functionality of Na+ channels and the corresponding Na+ currents can be investigated using the patch-clamp technique, the latter is rather invasive and a technically difficult method to study intracellular Na+ transients compared to Na+ fluorescence imaging. Despite the fact that Na+ signaling is considered an important controller of cancer progression, only few data using Na+ imaging approaches are available so far, suggesting the persisting challenge within the scientific community. In this study, we describe in detail the approach for application of Na+ imaging technique to measure intracellular Na+ variations in human prostate cancer cells. Accordingly, we used three Na+-specific fluorescent dyes-Na+-binding benzofuran isophthalate (SBFI), CoroNa™ Green (Corona) and Asante NaTRIUM Green-2 (ANG-2). These dyes have been assessed for optimal loading conditions, dissociation constant and working range after different calibration methods, and intracellular Na+ sensitivity, in order to determine which probe can be considered as the most reliable to visualize Na+ fluctuations in vitro.

Keywords: ANG-2; CoroNa Green; Fluorescent dye; Prostate cancer cells; SBFI; Sodium imaging.

Publication types

  • Comparative Study

MeSH terms

  • Calibration
  • Cell Line, Tumor
  • Cytosol / drug effects
  • Cytosol / metabolism
  • Enzyme Inhibitors / pharmacology
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • Fluorescent Dyes / metabolism*
  • Humans
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism*
  • Ion Channel Gating / drug effects
  • Male
  • Molecular Imaging / methods*
  • Prostatic Neoplasms / pathology*
  • Sodium / metabolism*
  • Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors
  • Voltage-Gated Sodium Channels / metabolism


  • Enzyme Inhibitors
  • Fluorescent Dyes
  • Voltage-Gated Sodium Channels
  • Sodium
  • Sodium-Potassium-Exchanging ATPase