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The aim of this study was to investigate the effect of diallyl disulfide (DADS) on the apoptosis of K562 cells and to explore the mechanism of K562 apoptosis induced by DADS. The K562 cells were treated with different concentrations of DADS for 24, 48 and 72 hours. The concentrations of DADS were as follows: 0 (control group), 10, 20, 40 and 80 mg/L. The morphologic changes of leukemia K562 cells treated with DADS were observed by Hoechst33 258 staining. The apoptosis of K562 cells treated with different concentrations of DADS for 24, 48 and 72 hours was analyzed by flow cytometry. The mRNA expression changes of Fas and FasL were detected by reverse transcription-polymerase chain reaction (RT-PCR) after K562 cells were treated with different concentrations of DADS for 48 hours. The results indicated that the characteristics of apoptosis in K562 cells induced by DADS were as follows: reduction of nucleus, chromatin condensation and nuclear membrane rupture. The flow cytometry with PI straining showed that after 24 hours of DADS treatment the apoptosis rate of K562 cells increased from 11.60 ± 0.83% at the concentration of 10 mg/L to 37.94 ± 0.87% at the concentration of 40 mg/L. The apoptosis rate of K562 cells increased from 37.94 ± 0.87% (24 hours) to 47.02 ± 0.66% (72 hours) after treatment with DADS of 10 mg/L increasing to 40 mg/L DADS. The Fas mRNA expression levels of the related apoptotic genes increased after K562 cells were treated with different concentrations of DADS for 48 hours, while FasL mRNA expression decreased significantly after DADS treatment for 48 hours, compared with those in the control group (p < 0.05). It is concluded that DADS can induce the apoptosis of human leukemia K562 cells in a time-and concentration-dependent manners. The activation of Fas/FasL pathway may play an important role in the K562 cell apoptosis induced by DADS, which is associated with increasing Fas gene expression and decreasing FasL gene expression.

Objective: To study the effects of diallyl disulfide (DADS) on apoptosis of human leukemia K562 cells and possible mechanisms., Methods: The morphologic changes of leukemia K562 cells after DADS treatment were observed by Hoechst 33258 staining. Cell apoptosis rates after different concentrations and different durations of DADS treatment were determined by flow cytometry. Fas, FasL and caspase-8 mRNA expression was estimated by reverse transcription-polymerase chain reaction (RT-PCR) 48 hrs after DADS treatment., Results: The characteristics of apoptosis in K562 cells induced by DADS were observed. After 24 hrs of DADS treatment, the apoptosis rate of K562 cells increased from (11.60 ± 0.83)% at the concentration of 10 mg/L to (37.94 ± 0.87)% at the concentration of 40 mg/L. The apoptosis rate of K562 cells increased after 40 mg/L DADS with the increasing time from (37.94 ± 0.87)% (24 hrs) to (47.02 ± 0.66)% (72 hrs). Expression of Fas and caspase-8 mRNA increased, while FasL mRNA expression decreased significantly 48 hrs after DADS treatment compared with the control group (P<0.05)., Conclusions: DADS can induce apoptosis of human leukemia K562 cells in a time- and concentration-dependent manner, possibly through increasing Fas and caspase-8 expression and decreasing FasL expression.