[Effects of dihydroartemisinin on radiosensitivity of Raji cells]

To study the effects of dihydroartemisinin (DHA) on radiation sensitivity of Raji cells, and explore its mechanisms.

CCK8 was used to determine the effect of DHA on cell viability of Raji cells; apoptosis, intracellular reactive oxygen speies(ROS) and mitochondrial membrane potential of Raji cells were detected by flow cytometry; and the protein expressions of protein kinase B(AKT), phospho-rylated-protein kinase B(p-AKT), Bcl-2 and Bax were determined by Western blot.

The cells were randomly divided into four groups:control group, DHA(5μmol/L DHA), irradiation(IR, 4 Gy), IR+DHA group (4 Gy IR+5 μmol/L DHA). Compared with the other three groups, cells in DHA+IR group exhibited lower mitochondrial membrane potential (P<0.01). While the intracellular ROS content and apoptosis rate of Raji cells in DHA+IR group were increased significantly(P<0.01). In addition, compared with the other three groups, there was no significant difference in the expression of AKT, but the phosphorylation of AKT protein were significantly inhibited and the expression of Bcl-2 protein was markedly decreased. However, the expressions of Bax and Cleaved-Caspase-3 protein were markedly increased.

DHA might activate the mitochondrial apoptotic signal via inhibiting phosphoinositide 3-kinase (PI3K/AKT) pathway and increase oxidative stress to enhance the radiosensitivity of Raji cells.