Apamin is an integral part of
bee venom, as a
peptide component. It has long been known as a highly selective block Ca(2+)-activated K(+) (SK) channels. However, the cellular mechanism and anti-fibrotic effect of
apamin in TGF-β1-induced hepatocytes have not been explored. In the present study, we investigated the anti-
fibrosis or anti-EMT mechanism by examining the effect of
apamin on TGF-β1-induced hepatocytes. AML12 cells were seeded at ∼60% confluence in complete growth medium. Twenty-four hours later, the cells were changed to serum free medium containing the indicated concentrations of
apamin. After 30 min, the cells were treated with 2 ng/ml of TGF-β1 and co-cultured for 48 h. Also, we investigated the effects of
apamin on the CCl4-induced
liver fibrosis animal model. Treatment of AML12 cells with 2 ng/ml of TGF-β1 resulted in loss of
E-cadherin protein at the cell-cell junctions and concomitant increased expression of
vimentin. In addition, phosphorylation levels of ERK1/2, Akt, Smad2/3 and Smad4 were increased by TGF-β1 stimulation. However, cells treated concurrently with TGF-β1 and
apamin retained high levels of localized expression of
E-cadherin and showed no increase in
vimentin. Specifically, treatment with 2 μg/ml of
apamin almost completely blocked the phosphorylation of ERK1/2, Akt, Smad2/3 and Smad4 in AML12 cells. In addition,
apamin exhibited prevention of pathological changes in the CCl4-injected animal models. These results demonstrate the potential of
apamin for the prevention of EMT progression induced by TGF-β1 in vitro and CCl4-injected in vivo.