Figure 5 : Luteolin promoting XIAP Protein Degradation. (A) HepG2 cells were treated with luteolin (30μM), FasL (60ng/ml) and the both for 12, 24 h. Total RNA was isolated and RT-PCR was performed. XIAP mRNA levels were measured with 1.2% agarose gels stained with EtBr, and β-actin mRNA was used as control. (B) HepG2 cells were pretreated with proteasome inhibitor MG132 (20μM) for 1 hour, followed by combined treatment with luteolin (30μM × 24h) and FasL (60ng/ml × 22h). XIAP protein level was determined by Western blotting. (C) HepG2 cells and L02 cells were treated with luteolin, FasL alone and combination with luteolin (30 μM × 24h) and FasL (60ng/ml × 22h). Cell lysate was used for Tunel assay.