[Effects of Osthole on Apoptosis of HL-60 Cells Induced by TRAIL and Its Related Mechanism].

OBJECTIVE: To explore the effects of Osthole on apoptosis of HL-60 cells induced by tumor necrosis factor related apoptosis inducing ligand (TRAIL) and its possible mechanism.

METHODS: The proliferative inhibition of HL-60 cells treated with different concentrations of Osthole, TRAIL alone and Osthole combined with TRAIL was measured by MTT assay. The HL-60 cells were treated with Osthole, TRAIL alone and Osthole combined with TRAIL at the concentration<IC50 value, i.e. 100µmol/L for Osthole and 40 ng/ml for TRAIL. Apoptosis and mitochondrial membrane potential (MMP) of HL-60 cells were detected by flow cytometry; the mRNA expression of BCL-2, BAX and DR5 was determined by RT-PCR; and the levels of Caspase-3,-8,-9 activity were detected by spectrophotometry.

RESULTS: The combined treatment (100µmol/L Osthole + 40 ng/ml TRAIL) of HL-60 cells for 48 h induced an apoptotic rate of (33.9±2.7) %, which was significantly higher than that of cells treated with Osthole or TRAIL alone (P<0.05); at the same time, the combined treatment promoted the decrease of MMP and the expression rate of BCL-2/BAX, and potentiated the expression of DR5 and Caspase-3,-8,-9 activity.

CONCLUSION: Osthole can sensitize HL-60 cells to TRAIL-induced apoptosis, which may be related with the activation of mitochondrial pathways and up-regulation of DR5.