Roles and mechanisms of Fas/FasL in the apoptosis of HL-60 cells induced by euphorbiasteroid

Objective To investigate the effect of euphorbiasteroid on inducing the apoptosis of HL-60 cells and demonstrate whether the Fas/FasL signaling pathway is involved in the induction of apoptosis. Methods HL-60 cells were treated with dose of 2.5,10,40 μg/ml of euphorbiasteroid in vitro for 24 h respectively.After that,cell counting Kit-8 was used to detect cell proliferation.The morphology of HL-60 cells were observed under light and fluorescent microscopy.The early cell apoptosis was detected by using flow cytometry with Annexin Ⅴ-FITC /PI double staining.The expressions of Fas,FasL,caspase-8 and caspase-3 mRNA were analyzed by the method of RT-PCR.The activities of caspase-8 and caspase-3 were examined by chromatometry.Results Compared with 1640 control group,HL-60 cell proliferation was inhibited significant-ly by euphorbiasteroid.The inhibition rates were （34.9 ±3.7）%,（54.6 ±5.2）% and （61.3 ±4.3）%respectively.Moreover,HL-60 cells exhibited typical morphological features.Early cell apoptosis rates of HL-60 cells were （23.4 ±3.1）%,（35.7 ±4.3）% and （53.2 ±3.9）% respectively.Furthermore,the expressions of Fas,FasL,caspase-3 and caspase-8 mRNA were up-regulated significantly after euphorbiasteroid administration in a dose-dependent manner （P<0.01 ）.After treated with euphorbiasteroid,the activities of caspase-8 and caspase-3 were significantly enhanced （P<0.01 ）.Conclusion The up-regulation effect of euphorbiasteroid on Fas/FasL signaling pathway might contribute to the apoptosis of HL-60 cells. Key words: Fas/FasL; HL-60 cells; Apoptosis; Fas/FasL; Euphorbiasteroid