Ouadid-Ahidouch H, Chaussade F, Roudbaraki M, Slomianny C, Dewailly E, Delcourt P, Prevarskaya N
Laboratoire de Physiologie Cellulaire, INSERM, SN3, USTL, Villeneuve d'Ascq, 59655, France.
Biochem Biophys Res Commun. 2000 Nov 19;278(2):272-7. doi: 10.1006/bbrc.2000.3790.
Electrophysiological, immunocytochemical, and RT-PCR methods were used to identify a K(+) conductance not yet described in MCF-7 human breast cancer cells. A voltage-dependent and TEA-sensitive K(+) current was the most commonly observed in these cells. The noninactivating K(+) current (I(K)) was insensitive to iberiotoxin (100 nM) and charybdotoxin (100 nM) but reduced by alpha-dendrotoxin (alpha-DTX). Perfusion of alpha-DTX reduced a fraction of I(K) amplitude in a dose-dependent manner (IC(50) = 0.6 +/- 0.3 nM). This DTX sensitive I(K) exhibited a voltage threshold at -20 mV and was not inactivated. The time constant of activation was 5.3 +/- 2.2 ms measured at +60 mV. The averaged half-activation potential and slope factor values were 14 +/- 1.6 mV and 10 +/- 1.4, respectively. Immunocytochemical analysis demonstrated that plasma membrane was labeled by anti-Kv1.1 but not by anti-Kv1.2 nor anti-Kv1.3 antibodies. Furthermore, only Kv1.1 mRNA was detected in MCF-7 cells. Incubation in 1 and 10 nM alpha-DTX reduced cell proliferation by 20 and 30%, respectively. These data provide the first evidence of Kv1.1 K(+) channels expression in MCF-7 cells and indicate that these channels are implicated in cell proliferation.
采用电生理、免疫细胞化学和逆转录聚合酶链反应（RT-PCR）方法，在MCF-7人乳腺癌细胞中鉴定一种尚未被描述的钾离子电导。在这些细胞中最常观察到一种电压依赖性且对四乙铵（TEA）敏感的钾离子电流。非失活钾离子电流（I(K)）对iberiotoxin（100 nM）和charybdotoxin（100 nM）不敏感，但可被α-银环蛇毒素（α-DTX）降低。灌注α-DTX以剂量依赖性方式降低了一部分I(K)幅度（IC(50)=0.6±0.3 nM）。这种对DTX敏感的I(K)在-20 mV时表现出电压阈值且不会失活。在+60 mV时测得的激活时间常数为5.3±2.2毫秒。平均半激活电位和斜率因子值分别为14±1.6 mV和10±1.4。免疫细胞化学分析表明，质膜被抗Kv1.1抗体标记，但未被抗Kv1.2和抗Kv1.3抗体标记。此外，在MCF-7细胞中仅检测到Kv1.1 mRNA。在1 nM和10 nM的α-DTX中孵育分别使细胞增殖降低了20%和30%。这些数据首次证明了Kv1.1钾离子通道在MCF-7细胞中的表达，并表明这些通道与细胞增殖有关。
