Induction of apoptosis by a hexane extract of aged black garlic in the human leukemic U937 cells.
- Author:
Cheol PARK
1
;
Sejin PARK
;
Yoon Ho CHUNG
;
Gi Young KIM
;
Young Whan CHOI
;
Byung Woo KIM
;
Yung Hyun CHOI
Author Information
- Publication Type:Original Article
- Keywords: Aged black garlic; U937 cells; apoptosis; caspase
- MeSH: Apoptosis*; Blotting, Western; Caspase 3; Caspase 8; Caspase 9; Cell Death; Electrophoresis, Agar Gel; Flow Cytometry; Garlic*; Humans*; Leukemia; Receptors, TNF-Related Apoptosis-Inducing Ligand; Survival Rate; U937 Cells*; Up-Regulation
- From:Nutrition Research and Practice 2014;8(2):132-137
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND/OBJECTIVES: In this study, the apoptogenic activity and mechanisms of cell death induced by hexane extract of aged black garlic (HEABG) were investigated in human leukemic U937 cells. MATERIALS/METHODS: Cytotoxicity was evaluated by MTT (3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazoliumbromide) assay. Apoptosis was detected using 4,6-diamidino-2-phenyllindile (DAPI) staining, agarose gel electrophoresis and flow cytometry. The protein levels were determined by Western blot analysis. Caspase activity was measured using a colorimetric assay. RESULTS: Exposure to HEABG was found to result in a concentration- and time-dependent growth inhibition by induction of apoptosis, which was associated with an up-regulation of death receptor 4 and Fas legend, and an increase in the ratio of Bax/Bcl-2 protein expression. Apoptosis-inducing concentrations of HEABG induced the activation of caspase-9, an initiator caspase of the mitochodrial mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase. HEABG also induced apoptosis via a death receptor mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid, and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. However, pre-treatment of U937 cells with the caspase-3 inhibitor, z-DEVD-fmk, significantly blocked the HEABG-induced apoptosis of these cells, and increased the survival rate of HEABG-treated cells, confirming that HEABG-induced apoptosis is mediated through activation of caspase cascade. CONCLUSIONS: Based on the overall results, we suggest that HEABG reduces leukemic cell growth by inducing caspase-dependent apoptosis through both intrinsic and extrinsic pathways, implying its potential therapeutic value in the treatment of leukemia.
