Abstract.
K+ channels, membrane voltage, and intracellular free Ca2+ are involved in regulating proliferation in a human melanoma cell line (SK MEL 28). Using patch-clamp techniques, we found an inwardly rectifying K+ channel and a calcium-activated K+ channel. The inwardly rectifying K+ channel was calcium independent, insensitive to charybdotoxin, and carried the major part of the whole-cell current. The K+ channel blockers quinidine, tetraethylammonium chloride and Ba2+ and elevated extracellular K+ caused a dose-dependent membrane depolarization. This depolarization was correlated to an inhibition of cell proliferation. Charybdotoxin affected neither membrane voltage nor proliferation. Basic fibroblast growth factor and fetal calf serum induced a transient peak in intracellular Ca2+ followed by a long-lasting Ca2+ influx. Depolarization by voltage clamp decreased and hyperpolarization increased intracellular Ca2+, illustrating a transmembrane flux of Ca2+ following its electrochemical gradient. We conclude that K+ channel blockers inhibit cell-cycle progression by membrane depolarization. This in turn reduces the driving force for the influx of Ca2+, a messenger in the mitogenic signal cascade of human melanoma cells.
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Received: 9 May 1995/Revised: 30 January 1996
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Lepple-Wienhues, A., Berweck, S., Böhmig, M. et al. K+ Channels and the Intracellular Calcium Signal in Human Melanoma Cell Proliferation. J. Membrane Biol. 151, 149–157 (1996). https://doi.org/10.1007/s002329900066
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DOI: https://doi.org/10.1007/s002329900066