title: Oscillating activity of a Ca(2+)-sensitive K+ channel. A prerequisite for migration of transformed Madin-Darby canine kidney focus cells.
abstract: Migration plays an important role in the formation of tumor metastases. Nonetheless, little is known about electrophysiological phenomena accompanying or underlying migration. Previously, we had shown that in migrating alkali-transformed Madin-Darby canine kidney focus (MDCK-F) cells a Ca(2+)-sensitive 53-pS K+ channel underlies oscillations of the cell membrane potential. The present study defines the role this channel plays in migration of MDCK-F cells. We monitored migration of individual MDCK-F cells by video imaging techniques. Under control conditions, MDCK-F cells migrated at a rate of 0.90 +/- 0.03 microns/min (n = 201). Application of K+ channel blockers (1 and 5 mmol/liter Ba2+, 5 mmol/liter tetraethylammonium, 100 mumol/liter 4-aminopyridine, 5 nmol/liter charybdotoxin) caused marked inhibition of migration, pointing to the importance of K+ channels in migration. Using patch-clamp techniques, we demonstrated the sensitivity of the Ca(2+)-sensitive 53-pS K+ channel to these blockers. Blockade of this K+ channel and inhibition of migration were closely correlated, indicating the necessity of oscillating K+ channel activity for migration. Migration of MDCK-F cells was also inhibited by furosemide or bumetanide, blockers of the Na+/K+/2Cl- cotransporter. We present a model for migration in which oscillations of cell volume play a central role. Whenever they are impaired, migration is inhibited.
authors.affiliation: Physiologisches Institut, Universität Würzburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schwab
authors.forename: L
authors.initials: L
authors.lastname: Wojnowski
authors.forename: K
authors.initials: K
authors.lastname: Gabriel
authors.forename: H
authors.initials: H
authors.lastname: Oberleithner
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology*; D002461:Cell Line, Transformed; D002465:Cell Movement; D002478:Cells, Cultured; D004285:Dogs; D007668:Kidney / Q000166:cytology*; D008564:Membrane Potentials; D015221:Potassium Channels / Q000502:physiology*
chemical_list: D015221:Potassium Channels; D002118:Calcium