Roles of NADPH oxidases in cisplatin-induced reactive oxygen species generation and ototoxicity.
In our previous study, we clearly demonstrated the roles of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1beta (IL-1beta), and IL-6, and subsequent reactive oxygen species (ROS) generation on the pathogenesis of cisplatin ototoxicity in vitro and in vivo. ROS generation in cisplatin-treated HEI-OC1 auditory cells was also correlated with changing mitochondrial membrane potential. However, the roles of NADPH oxidase in cisplatin-induced ROS generation and ototoxicity have not been fully elucidated. Herein, immunohistochemical studies demonstrated that treatment of cisplatin induced the expression of NADPH oxidase isoforms NOX-1 and NOX-4 in HEI-OC1 auditory cells. Expression of mRNA for NOX-1, NOX-4, NOXO1, NOXA1, p47(phox), and p67(phox) was also increased. Inhibition of NADPH oxidase with diphenyleniodonium chloride or apocynin abolished ROS production and the subsequent apoptotic cell death in cisplatin-treated cells. Furthermore, suppression of NOX1 and NOX4 expression by small interfering RNA transfection markedly abolished the cytotoxicity and ROS generation by cisplatin. Together, our data suggest that ROS generated, in part, through the activation of NADPH oxidase plays an essential role in cisplatin ototoxicity.
Vestibulocochlear Research Center and Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, 570-749, Korea.
Hyung-Jin
HJ
Kim
Jeong-Han
JH
Lee
Se-Jin
SJ
Kim
Gi Su
GS
Oh
Hae-Dalma
HD
Moon
Kang-Beom
KB
Kwon
Channy
C
Park
Byung Hyun
BH
Park
Ho-Kyun
HK
Lee
Sang-Young
SY
Chung
Raekil
R
Park
Hong-Seob
HS
So
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002461:Cell Line, Transformed; D002945:Cisplatin / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000633:toxicity*; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects* / Q000201:enzymology*; D034381:Hearing Loss / Q000139:chemically induced / Q000378:metabolism; D007274:Injections, Intraperitoneal; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019255:NADPH Oxidases / Q000502:physiology*; D009924:Organ Culture Techniques; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000378:metabolism*
D017382:Reactive Oxygen Species; D019255:NADPH Oxidases; D002945:Cisplatin