The effects of CDDP on the progress of apoptosis in glioma cell induced by TRAIL/APO-2L

Objective To investigate the effects of TRAIL on apoptosis in human glioma cell line and study the mechanism of CDDP on apoptotic process induced by TRAIL . Methods Different doses of CDDP was added in the media of glioma cells with treatment of different doses of TRAIL, then viability was examined by MTT assay. Afterwards, sub-poisonous dose of TRAIL and CDDP were added into media of glioma cells, the apoptotic percentages of three experimental groups that included the TRAIL, CDDP and TRAIL-CDDP groups were examined by FCM. Western blot assay was used to examine the expression of DR5 with or without CDDP. Results Within a certain time, when the doses of TRAIL and CDDP increased, the viability of U251 glioma cell became lower synchronously. The viability of glioma cells induced by TRAIL, CDDP and TRAIL-CDDP which were 50 ng·ml -1 and 4μg·ml -1and 50 ng·ml -1- 4μg·ml -1 were 72.43% , 75.56% and 23.45%,respectively. The apoptotic percentages of glioma cells induced by TRAIL, CDDP and TRAIL-CDDP were 25.61%,20.59% and 62.33%, respectively. The apoptotic percentages of glioma cells induced by CDDP and TRAIL were significantly lower than that by TRAIL-CDDP(P0.01). Western blot showed that the expression of DR5 of cells with CDDP was higher than that without CDDP. The expression of DR5 was increased gradually within certain time. Conclusions The apoptosis of glioma cell induced by TRAIL-CDDP was significantly higher than that of cells treated by TRAIL or CDDP solely. The mechanism may be that the expression of DR5 was up-regulated by CDDP.