Mechanism of Cyclosporin A-induced Apoptosis in HL-60 Cell Line

Objective: To investigate the effect of CsA on apoptosis of HL-60 cells and its mechanism. Methods: Apoptosis of HL-60 cells induced by CsA was studied by light microscopy, TdT-mediated dUTP nick end labeling (TUNEL) and flow cytometry (FCM); The effect of CsA on the expresion of bcl-2 gene was detected by FCM. Results: HL-60 cells which were induced by the concentration of 20 mg/L CsA cultured for 6 hours, exhibited typical apoptotic morphological changes under light microscopy. The apoptotic peak was clearly displayed by FCM and HL-60 cells were arrested by CsA in the stage Go to Gi. The apoptosis rate was significandy higher in CsA-treated groups than that in the alcohol group (P 0. 01) . The expression rate of transcription protein from bcl-2 was significantly lower in CsA-treated groups than that in the alcohol group( P 0. 01). Conclusion: CsA-induced apoptosis of HL-60 cells is probably associated with down-regulating expression of bcl-2 gene.