OBJECTIVETo investigate the inhibitory effect of giganteaside D (GD) on hepatocellular carcinoma and its molecular mechanisms.

METHODSThe inhibitory effects of GD on Hep 3b cells were determined using MTT assay and colony formation assay. The morphological changes of Hep 3b cells after GD treatment were observed by electron microscopy, and the cell cycle changes was analyzed using flow cytometry. The cell apoptosis and mitochondrial potential collapse in the treated cells were tested with Hoechst staining assay and flow cytometry. The expression levels of Bcl-2, PARP and key proteins in MAPK pathway were detected using Western blotting.

RESULTSGD showed a significant inhibitory effect on Hep 3b cells with an ICvalue of 16.08 µmol/L at 72 h. Flow cytometric analysis demonstrated that the phases of cell cycle remained unchanged and a sub-G1 peak (from 3.3% to 33.6%) appeared as GD concentration increased. GD-induced apoptosis was further conformed by Hoechst staining assay, and flow cytometry showed increased mitochondrial potential collapse in the cells. Western blotting demonstrated the cleavage of PARP, decrease of Bcl-2 and p-Erk1/2 (Thr202/Tyr204), and activation of p-p38 (Thr180/Tyr182) and p-JNK (Thr183/Tyr185) in GD-treated cells.

CONCLUSIONSGD has significant inhibitory effect against hepatocellular carcinoma cells in vitro by inducing apoptosis possibly in association with the MAPK signaling pathway.