Recently, we and other groups revealed that aberrant expression of Kv10.1 channel, a voltage-gated
potassium ion channel, contributes to a variety of
tumorigenesis process.Potent and selective inhibitor of Kv10.1 is urgently needed, both as pharmacological tools for studying the physiological functions of this enigmatic channel and as potential leads for development of anti-
tumor drugs. In this study,
Procyanidin B1, a natural compound extracted from the grape seed, was identified as a potent, specific inhibitor, which can inhibit the Kv10.1 channel in a concentration-dependent manner (IC50 = 10.38 ± 0.87 μM), but has negligible effects on other
potassium channels, including Kir2.1, HERG or KCNQ1. It was demonstrated that
Procyanidin B1 directly binds to Kv10.1 channel and inhibits its currents, without increasing intracellular Ca2+. Further, three
amino acids, I550, T552, and Q557 in the C-linker domain of Kv10.1 were found critical for forming the binding pocket of
Procyanidin B1 with Kv10.1 channel.In addition,
Procyanidin B1 inhibits migration and proliferation of
liver cancer cells (HuH-7 cells, HepG2 cells) through inhibiting Kv10.1, but not in Kv10.1 negatively expressed cell lines. Next, we assayed the
tumor suppressing effect of
Procyanidin B1 on cell line-derived xenograft mouse model. Our data showed that 15 mg/kg
Procyanidin B1 can significantly suppress the growth of the
tumor (HepG2) with an inhibition rate of about 60.25%. Compared with
cisplatin,
Procyanidin B1 has no side effect on the normal metabolismof the mice. The present work indicated that
Procyanidin B1 is a proming
liver cancer anti-
tumor drug, and also confirmed that Kv10.1 can serve as a potential,
tumor-specific
drug target.