Effect of Shikonin on Autophagy and Apoptosis of Human Promyelocytic Leukemia Cells
Objective:To explore the effect of shikonin on autophagy and apoptosis of human promyelocytic leukemia cells and its possible mechanism.Methods:Human promyelocytic leukemia cells NB4 in the logarithmic growth phase were divided into control group(untreated NB4 cells),shikonin group(0.3 μmol/L shikonin treatment),740Y-P group(15 μmol/L PI3K/Akt/mTOR pathway activator 740Y-P treatment),shikonin+740Y-P group(0.3 μmol/L shikonin and 15 μmol/L 740Y-P co-treatment),after 24 hours of treatment,the cells were used for subsequent experiments.CCK-8 method was used to detect cell viability,monodansylcadaverine(MDC)staining to detect the aggregation of autophagic vesicles,flow cytometry to detect cell apoptosis,and Western blot to detect the expression of Beclinl,LC3,p62,Bax,cleaved caspase-3,Bcl-2 and PI3K/Akt/mTOR pathway related proteins.Results:Compared with the control group,the purple punctate fluorescence intensity,apoptosis rate,Beclinl,LC3-Ⅱ/LC3-Ⅰ,cleaved caspase-3,and Bax protein expression in NB4 cells were increased in the shikonin group,while OD450 value(24,48 h)and the expressions of Bcl-2 and p62 proteins were decreased(all P<0.05).Compared with the control group,the purple punctate fluorescence intensity,apoptosis rate,Beclin1,LC3-Ⅱ/LC3-1,cleaved caspase-3,and Bax protein expression in NB4 cells were decreased,while OD450 value(24,48 h)and the expressions of Bcl-2 and p62 proteins were increased in the 740Y-P group(all P<0.05).Compared with the shikonin group,the purple punctate fluorescence intensity,apoptosis rate,Beclinl,LC3-Ⅱ/LC3-1,cleaved caspase-3,and Bax protein expression in NB4 cells were decreased,while OD450 value(24,48 h)and the expressions of Bcl-2 and p62 proteins were increased in the shikonin+740Y-P group(all P<0.05).Compared with the control group,the expression of PI3K/Akt/mTOR pathway related proteins p-PI3K,p-Akt,and p-mTOR in NB4 cells were significantly decreased in the shikonin group,while those in the 740Y-P group were increased(all P<0.05).Compared with the shikonin group,the expressions of p-PI3K,p-Akt,and p-mTOR proteins in NB4 cells were significantly increased in the shikonin+740Y-P group(all P<0.05).Conclusion:Shikonin may promote autophagy and apoptosis of NB4 cells by inhibiting PI3K/Akt/mTOR pathway.
shikoninphosphatidylinositol 3 kinases/protein kinase B/mammalian target of rapamycin pathwaypromyelocytic leukemiaautophagyapoptosis