Apoptosis assay

The apoptotic rates of SGC7901/DDP and SGC7901 cells were evaluated by flow cytometry (FCM) with an Annexin V-FITC/propidium iodide (PI) Cell Apoptosis Detection kit (BestBio). SGC7901/DDP and SGC7901 cells (~1×10⁶ cells) were treated with cisplatin at a final concentration of 0.8 and 0.3 µg/ml, respectively. Following 48 h of treatment at 37°C the cells were collected and washed twice with ice-cold PBS. Cells were resuspended with 400 µl of 1X binding buffer and maintained at a final density of approximately 1×10⁶ cells/ml. Annexin V-FITC (5 µl) was added to the suspension, which was incubated in the dark for 15 min at room temperature. Following the addition of PI (10 µl) to the suspension, cells were incubated for an additional 5 min in the dark at room temperature. Subsequently, cell apoptosis was assessed (early + late) using a Gallios flow cytometer (Beckman Coulter, Inc.).