Cell Cycle Analysis of As4S4 and As3+ in APL

The effects of As₄S₄ and As³⁺ on cell cycle distribution were determined using a PI cell cycle detection kit (KeyGEN Biotech, China) [28 (link)]. After treatment with As₄S₄ (2.0 μM), As³⁺ (2.0 μM), or a combination of 1.0 μM As₄S₄ and 1.0 μM As³⁺ for 48 h, NB4 and primary APL cells were collected, washed with Ca²⁺-free PBS and fixed with 70% ethanol at 4°C for 16 h. The fixed cells were then digested in PBS containing 0.5 mg/ml RNase (Sigma-Aldrich, USA) at 37°C for 30 min and stained with 0.05 mg/ml PI in the dark at room temperature for 30 min. Data on the cell cycle distribution were determined using the ModFit LT 3.3 software.