Involvement of K+ channels in the quercetin-induced inhibition of neuroblastoma cell growth.

The effects of the flavonoid quercetin on cell proliferation and voltage-dependent K+ current were studied on mouse neuroblastoma x glioma hybrid cells. In the presence of 1% fetal calf serum, quercetin inhibited both cell proliferation and K+ current with effective doses inducing half-maximum effects of 10 microM and 70 microM respectively. Valinomycin (1 nM) antagonized 80% of the growth-inhibitory effects of 10 microM quercetin. The results suggest that at least a part of the anti-proliferative effect of quercetin is mediated by a K+ channel blockade. They further confirm a role for K+ channels in mitogenesis and cell proliferation.