Diepoxybutane activates the mitochondrial apoptotic pathway and mediates apoptosis in human lymphoblasts through oxidative stress

Abstract

Diepoxybutane (DEB) is the most potent metabolite of the environmental chemical 1, 3-butadiene (BD), which is prevalent in petrochemical industrial areas. BD is a known mutagen and human carcinogen, and possesses multi-systems organ toxicity. We recently reported that DEB-induced cell death in TK6 lymphoblasts was due to the occurrence of apoptosis, and not necrosis. In this study, we investigated the molecular mechanisms responsible for DEB-induced apoptosis in these cells. Bax and Bak were found to be over-expressed and activated, and the mitochondrial trans-membrane potential was attenuated in cells undergoing DEB-induced apoptosis. Cytochrome c was depleted from the mitochondria of TK6 cells undergoing apoptosis, and was released into the cytosol in Jurkat-T lymphoblasts exposed to the same concentrations of DEB. Executioner caspase 3 was deduced to be activated by initiator caspase 9. DEB induced reactive oxygen species (ROS) formation, and the ROS scavenger N-acetyl-L-cysteine effectively blocked DEB-induced apoptosis in TK6 cells.Collectively, these results demonstrate that the mitochondrial apoptotic pathway is activated to mediate DEB-induced apoptosis in human TK6 lymphoblasts. These results further demonstrate that DEB-induced apoptosis is also mediated by the DEB-induced generation of ROS. This is the first report to examine the mechanism of DEB-induced apoptosis in human lymphoblasts.

Mechanism of diepoxybutane‐induced p53 regulation in human cells

“…The determination of the mechanism of DEB-induced p53 accumulation contributes toward the understanding of the molecular toxicity of DEB and butadiene. Since DEB-induced p53-mediated apoptosis in human TK6 lymphoblasts has previously been described [19,39,73], these studies are a necessary prerequisite to the understanding of the role p53 plays in DEB-induced apoptosis in this experimental system as well as other DEB systems.…”

Microcystin-RR induced apoptosis in tobacco BY-2 suspension cells is mediated by reactive oxygen species and mitochondrial permeability transition pore status

“…There are a great many evidences that ROS can induce apoptosis via several pathways, including either mitochondria-dependent or mitochondria-independent pathway in various cells and tissues (Krumschnabel et al, 2005;Wang et al, 2007;Yadavilli et al, 2007). In animal cells, previous results have demonstrated that MC-LR-induced rapid ROS generation led to apoptosis of primary rat hepatocytes through mitochondria-dependent pathway (Ding et al, 2000).…”

Induction of DNA Damage and G2 Cell Cycle Arrest by Diepoxybutane through the Activation of the Chk1-Dependent Pathway in Mouse Germ Cells

“…20,22 A recent study has shown the abnormal cell cycle distribution of human lung cells with DEB treatment. 48 These data indicated the possible presence of a relationship between oxidative stress and adverse effects of germ cells in DEB exposure.…”

“…As shown in Figure 1C, it was revealed that compared with the control, the cell proportion in the G 2 /M phase was accumulated significantly accompanied by a decrease in the G 0 /G 1 phase after exposure to DEB with 100, 300, and 500 μM for 24 h. For DEB, previous studies have reported that DEB possesses an apoptosis-inducing ability in human lymphoblasts. 22,27 On the basis of this, we assumed that DEB might play an important role in the inhibition of cell growth in vitro. In order to determine whether the growth decrease in DEB-treated GC-2 cells was due to apoptotic death, we tested the effect of DEB on apoptosis using flow cytometry.…”

“…20,21 It was also documented that DEB-induced apoptosis was mediated by the generation of ROS in human TK6 lymphoblasts. 22 Although oxidative stress has been implicated in DEB-induced cytotoxicity. 23 The extent and biological impact of oxidative stress-mediated damage in testicular cells after DEB exposure requires further investigation.…”