H. Ouadid-ahidouch et al., KV1.1 K+ channels identification in human breast carcinoma cells: Involvement in cell proliferation, BIOC BIOP R, 278(2), 2000, pp. 272-277
Citations number
30
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Electrophysiological, immunocytochemical, and RT-PCR methods were used to i
dentify a K+ conductance not yet described in MCF-7 human breast cancer cel
ls. A voltage-dependent and TEA-sensitive K+ current was the most commonly
observed in these cells. The noninactivating K+ current (I-K) was insensiti
ve 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 (IC50 = 0.6 +/- 0.3 nM). This DTX s
ensitive I-K exhibited a voltage threshold at -20 mV and was not inactivate
d. The time constant of activation was 5.3 a 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 an
ti-Kv1.3 antibodies. Furthermore, only Kv1.1 mRNA was detected in MCF-7 cel
ls. Incubation in 1 and 10 nlM alpha -DTX reduced cell proliferation by 20
and 30%, respectively. These data provide the first evidence of Kv1.1 K+ ch
annels expression in MCF-7 cells and indicate that these channels are impli
cated in cell proliferation. (C) 2000 Academic Press.