KV1.1 K(+) channels identification in human breast carcinoma cells: involvement in cell proliferation.
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.
Ouadid-Ahidouch
H
H
Laboratoire de Physiologie Cellulaire, INSERM, SN3, USTL, Villeneuve d'Ascq, 59655, France. ouadid.pop@univ.lille1.fr
Chaussade
F
F
Roudbaraki
M
M
Slomianny
C
C
Dewailly
E
E
Delcourt
P
P
Prevarskaya
N
N
D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D004546:Elapid Venoms / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D051662:Kv1.1 Potassium Channel; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D004546:Elapid Venoms; C496946:KCNA1 protein, human; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051662:Kv1.1 Potassium Channel; C020273:dendrotoxin