Rhein inhibits the growth and induces the apoptosis of Hep G2 cells

The effects of rhein on the human hepatoblastoma G2 (Hep G2) cell line were investigated in this study. The results showed that rhein not only inhibited Hep G2 cell growth but also induced apoptosis and blocked cell cycle progression in the G1 phase. An ELISA assay demonstrated that rhein significantly increased the expression of p53 and p21/WAF1 protein, which caused cell cycle arrest. An enhancement in CD95 and its two forms of ligands, membrane-bound CD95 ligand (mCD95L) and soluble CD95 ligand (sCD95L), might be responsible for the apoptotic effect induced by them. Taken together, p53 and the CD95/CD95L apoptotic system possibly participated in the antiproliferative activity of rhein in Hep G2 cells.