A Combination of Oridonin and TRAIL Induce Apoptosis in OCM-1A Cells and the Underlying Mechanism

Abstract

Objective: To study the inhibiting effect on OCM-1A cells and C918 cells from one of the choroidal melanoma cell lines by a combination of tumor necrosis factor related apoptosis inducing ligand (TRAIL) and Oridonin. Methods: In this basic experimental research, OCM-1A cells and C918 cells were cultured, and an experimental method was established to apply different concentrations of TRAIL (the final concentrations were 6.25, 1.25, 25, 50, 100, 200 ng/ml) and Oridonin (the final concentrations were 0.625, 1.25, 2.5, 5, 10, 20 μmol/L) to the OCM-1A and C918 cells. Then, the MTT method was used to detect cell proliferation activity. Cell cycle distribution and apoptosis were detected by flow cytometry, and the changes in apoptosis-related proteins such as DR5, a-Caspase-3 and XIAP were measured by Western blot. Data were analyzed using ANOVA and independent t test. Results: TRAIL had a certain degree of inhibition on OCM-1A cell proliferation. The highest inhibition rate was 36.5% when the concentration of TRAIL was 200 ng/ml. Inhibition of OCM-1A cell proliferation was not obvious with Oridonin. When TRAIL and Oridonin were simultaneously applied to OCM-1A cells, the inhibiting effect on OCM-1A was significantly enhanced. When TRAIL 200 ng/ml and Oridonin 20 μmol/L affected OCM-1A, the inhibition was the strongest, with an inhibition rate of 87%. The inhibitory effect on C918 was not significantly enhanced. The results of the cell cycle showed that TRAIL and Oridonin had an effect on OCM-1A cells with a significant blocking effect on G2/M. The results of Western blot showed that the expressions of DR5 and a-Caspase-3 were maintained, while the expression of apoptosis protein XIAP was suppressed. When TRAIL and Oridonin had a simultaneous effect on C918 cells, the apoptosis rate was not significantly different. Conclusions: The inhibiting effects of the combination of Oridonin with TRAIL on OCM-1A cells is significantly enhanced compared to the individual use of Oridonin or TRAIL alone. Key words: tumor necrosis factor related apoptosis inducing ligand; oridonin; apoptosis; choroidal melanoma