open access

https://hdl.handle.net/2115/38355

Redox regulation in radiation-induced cytochrome c release from mitochondria of human lung carcinoma A549 cells.

Redox regulation in radiation-induced cytochrome-c release from mitochondria of human lung carcinoma A549 cells.

英語

Electron spin resonance (ESR)

2009-05-08

Elsevier

Cancer Letters

277(1)

64-71

Mitochondria in mammalian cells were well-known to play an important role in the intrinsic pathway of genotoxic-agent-induced apoptosis by releasing cytochrome c into cytosol and to be a major source of reactive oxygen species (ROS). The aim of this study is to examine whether mitochondrial ROS involved in radiation-induced apoptotic signaling in A549 cells. The post-irradiation-treatment of N-acetyl-L-cystein (NAC) inhibited cytochrome c release from mitochondria but did not affect expression level of Bcl-2, Bcl-XL and Bax, suggesting late production of ROS triggered cytochrome c release. The experiments using DCFDA (a classical ROS fluorescence probe) and MitoAR (a novel mitochondrial ROS probe) demonstrated that intracellular and mitochondrial ROS were enhanced 6 h after X irradiation. Furthermore, the O2^[-.] production ability of mitochondria isolated from A549 cells was evaluated by ESR spectroscopy combined with a spin-trapping reagent (CYPMPO). When isolated mitochondria were incubated with NADH, succinate and CYPMPO, the ESR spectrum due to CYPMPO-OOH was detected. This NADH/succinate-dependent O2^[-.] production from mitochondria of irradiated cells was significantly increased in comparison with that of unirradiated cells. These results indicated that ionizing radiation enhanced O2^[-.] production from mitochondria to trigger cytochrome c release in A549 cells.

学術雑誌論文

Accepted Manuscript

0304-3835

AA00598513