Cell cycle: After pre-chilled PBS washes, cells were fixed with pre-chilled 70% ethanol for 2 h at 4℃. After 30 min of staining with propidium iodide (PI) solution, cells were then detected using a flow cytometer.
Apoptosis: Collected cells were stained with Annexin V-Fluorescein Isothiocyanate/PI according to the manuals (BD Pharmingen, USA). Detection was performed using a flow cytometer after 15 min. The assay was repeated for three times.