It has been shown that ion channels are involved in proliferation and in the development of cancer. To investigate the role of ion channels in cell proliferation we compared original slow growing T84 cells with spontaneously transformed fast growing T84 colonic carcinoma cells (T84 -fast). In T84 -fast we observed enhanced protein expression of the voltage dependent ether á gogo (Eag1) K+ channel and the putative Ca2+ activated Cl- channel Bestrophin-1 (best1). In T84 -fast cells expression of astemizole sensitive Eag1 currents was cell cycle dependent and had a larger impact on whole cell conductance and Ca2+ signaling during G1/S transition. T84 -fast showed elevated intracellular Ca2+ concentrations causes increased activity of Ca2+ activated Cl- channels. Downregulation of best1 by siRNA decreased cell proliferation in T84 -fast. These results confirm the role of Eag1 as cell cycle regulated K+ channel and establish a novel role of bestrophins in cell proliferation.

Supported by DFG Schr752/2-2

SFB 699 A7