Docetaxel Modulates the Delayed Rectifier Potassium Current (IK) and ATP-Sensitive Potassium Current (IKATP) in Human Breast Cancer Cells

Ion channel expression and activity may be affected during tumor development and cancer growth. Activation of potassium (K + ) channels in human breast cancer cells is reported to be involved in cell cycle progression. In this study, we investigated the effects of docetaxel on the delayed rectifier potassium current ( I K ) and the ATP-sensitive potassium current ( I KATP ) in two human breast cancer cell lines, MCF-7 and MDA-MB-435S, using the whole-cell patch-clamp technique. Our results show that docetaxel inhibited the I K and I KATP in both cell lines in a dose-dependent manner. Compared with the control at a potential of +60 mV, treatment with docetaxel at doses of 0.1, 1, 5, and 10 µM significantly decreased the I K in MCF-7 cells by 16.1 ± 3.5, 30.2 ± 5.2, 42.5 ± 4.3, and 46.4 ± 9 % ( n = 5, P