Objective: To observe the effect of programmed cell death 5 (PDCD5) protein on the apoptosis of multiple myeloma KM3 cells induced by dexamethasone and to understand its mechanism.
Methods: The human recombinant PDCD5 (rhPDCD5) protein was added (alone of different concentrations or associated with dexamethasone) into KM3 cells. Cultured together for certain time, the cells were collected for the following experiments: (1)The effect of rhPDCD5 protein and dexamethasone on the apoptotic rate of KM3 cells was determined by flowcytometry (FCM) analysis after the cells were stained by Annexin V-FITC & PI (propidium iodide). (2)Caspase-3 activity of KM3 cells was evaluated by Western blot. (3)The expression of survivin protein in KM3 cells was detected by immunocytochemistry.
Results: The apoptotic rate of KM3 cells and the activity of caspase-3 increased significantly, and that treated with rhPDCD5 protein and dexamethasone was higher than that treated with rhPDCD5 protein only. The expression of survivin protein in the rhPDCD5 with dexemethas group was down-regulated, and with the concentration of rhPDCD5 and dexamethasone increasing, the changes was more obviously.
Conclusion: PDCD5 protein can induce the apoptosis of KM3 cells, and accelerate the apoptosis of KM3 cells induced by dexamethasone. PDCD5 protein may reduce the expression of survivin protein and increase activation of caspase-3 to play its role in promoting apoptosis.