Subcellular localization of DJ-1 in human HL-60 leukemia cells in response to diallyl disulfide treatment

Abstract

Diallyl disulfide (DADS) has been demonstrated to exert potent anticancer effects in vitro and in vivo. Previous studies indicate that DADS may induce the differentiation and/or apoptosis of human leukemia cells in vitro. However, the mechanisms underlying these anticancer effects remain elusive. The aim of the present study was to investigate alterations in the subcellular localization of protein deglycase DJ-1 (also known as Parkinsonism associated deglycase-7, PARK-7) in the cytoplasm, nucleus and mitochondria of human leukemia HL-60 cells induced by DADS, in order to provide novel experimental evidence for the molecular mechanisms underlying the anticancer mechanisms of DADS in leukemia cells. HL-60 cells induced by DADS were collected at different time points, and proteins from the cytoplasm, nucleus and mitochondria of the cells were isolated using specific cellular component isolation kits. The protein expression levels of DJ-1 in these subcellular fractions of HL60 cells following exposure to DADS for varying lengths of time, were determined using western blotting, immunocytochemistry and immunofluorescence techniques. Following exposure of HL-60 cells to 1.25 mg/l DADS for 8 h, the protein expression levels of DJ-1 were significantly decreased in the cytoplasm, while nuclear fractions exhibited a significant increase in DJ-1 expression when compared with untreated controls. The protein expression levels of DJ-1 in mitochondria of HL-60 cells were significantly decreased following treatment with 5 and 10 mg/l DADS. These results demonstrate that exposure of HL-60 cells to low concentrations of DADS may promote DJ-1 protein translocation from the cytoplasm to the nucleus, which suggests that DJ-1 may function as a transcription factor or cofactor binding protein in the process of cell differentiation. The expression of DJ-1 in mitochondria may be associated with induction of apoptosis in HL-60 cells treated with moderate doses of DADS.