Oxaliplatin Sensitizes OS Cells to TRAIL-induced Apoptosis Via Down-regulation of Mcl1

Purpose: To investigate the killing effect on OS cells of a combination of oxaliplatin and TRAIL and relatedmolecular mechanisms.
Methods: TRAIL and oxaliplatin were applied to OS732 cells singly or jointly andsurvival inhibition rates were measured by MTT assay, changes of cellular shape being assessed with invertedphase contrast and fluorescence microscopy. Apoptotic rates were analyzed by flow cytometry (FCM) andimmunocytochemistry was used to examine Mcl1 expression of OS732 cells.
Results: The survival inhibition rateof combined application of 100 μg/ml TRAIL and 1 μg/ml oxaliplatin on OS-732 cells was significantly higherthan that of either agent singly (p<0.01). Changes of cellular shape and apoptotic rates also indicated apoptosisinducingeffects of combined application to be much stronger than those of individual application. Oxaliplatin hadthe effect of down-regulating Mcl1 expression and sensitizing OS cells to TRAIL-induced apoptosis.
Conclusion:A combination of TRAIL and oxaliplatin exerts strong killing effects on OS-732 cells which might be related todown-regulation of Mcl1 expression.