Antiproliferative effect of ME3738, a derivative of soyasapogenol, on hepatocellular carcinoma cell lines in vitro and in vivo.

Soyasapogenol, an aglycon of soyasaponin, ameliorates liver injury induced by concanavalin A in mice. A derivative of soyasapogenol, 22β-methoxyolean-12-ene-3β, 24(4β)-diol (ME3738), was reported to induce the gene expression of interferon (IFN)-β in hepatitis C virus replicon cells. The effect of ME3738 on hepatocellular carcinoma (HCC) cell lines was investigated in the present study. A total of 11 HCC cell lines were cultured in medium containing 0-10 µM ME3738, and after 24, 48, or 72 h of culture, morphological observation and MTT cell growth assays were performed. Furthermore, the effects of ME3738 with or without PEG-IFN-α-2b on cell lines were investigated. Induction of apoptosis was examined on cells treated with 1 µM of ME3738 using an Annexin V assay. The effect of ME3738 (0.63 and 2.5 µM) on cell cycle progression was analyzed on two cell lines. The mice with subcutaneous tumors were divided into four groups: i) Control; ii) ME3738 alone; iii) PEG-IFN-α-2b alone and iv) ME3738+PEG-IFN-α-2b (combination). ME3738 was mixed with food (1.5 mg/g) and was taken orally for 15 days. PEG-IFN-α-2b (1,920 IU/mouse) was subcutaneously injected twice a week for two consecutive weeks. On day 15, the mice were sacrificed and the tumors were resected. A dose-dependent anti-proliferative effect was observed to various degrees in all the HCC cell lines in vitro. This inhibitory effect reached its maximal level 24 h after the treatment and the 50% inhibitory dose was between 0.8 and 2.4 µM. The combination treatment did not show a synergistic effect. Induction of apoptosis was not observed. Cell cycle arrest at S-phase was observed in two of the examined cell lines. On day 15, the tumor volume of mice receiving ME3738, PEG-IFN-α-2b, and ME3738+PEG-IFN-α-2b was 69, 30, and 33%, respectively, of the control tumor volume. ME3738 induced antiproliferative effects on the HCC cells in vitro and in vivo. The data suggested potential clinical application of ME3738.