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.
European biophysics journal : EBJ. 2016 Sep 22 [Epub ahead of print]
Oksana Iamshanova, Pascal Mariot, V'yacheslav Lehen'kyi, Natalia Prevarskaya
Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université des Sciences et Technologies de Lille, 59656, Villeneuve d'Ascq, France., Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université des Sciences et Technologies de Lille, 59656, Villeneuve d'Ascq, France. .