Activation of a nuclear factor of activated T-lymphocyte-3 (NFAT3) by oxidative stress in carboplatin-mediated renal apoptosis.
OBJECTIVE
Although carboplatin is currently used as a therapeutic drug for ovarian, breast, and non-small cell lung cancers, it has serious side effects including renal and cardiac toxicity. Herein, we examined the effect of carboplatin on murine renal tubular cell (RTC) apoptosis both in vivo and in vitro and the underlying molecular mechanisms associated with its activation of the nuclear factor of activated T-lymphocytes-3 (NFAT3).


METHODS
Mechanisms of carboplatin-mediated renal apoptosis were examined using NFAT-reporter transgenic mice and RTCs with NFAT3 overexpression or knockdown.


RESULTS
We demonstrated that carboplatin initiated an intrinsic apoptotic pathway of activating caspase-3 and -9, accompanied by a decrease in the ratio of Bcl-XL/Bax and a significant increase in Bcl-XS. Carboplatin increased NFAT activation in NFAT-luciferase reporter transgenic mice, RTCs and cells exogenously overexpressing NFAT3 that exacerbated cell death. Furthermore, the addition of either N-acetylcysteine (NAC, an antioxidant) or NFAT inhibitors, including FK-506 (tacrolimus), cyclosporin A (CsA, a calcineurin inhibitor), and BAPTA-AM (a calcium chelator) successfully reversed carboplatin-mediated cell apoptosis, which was further confirmed using siNFAT3. Additionally, NAC blocked NFAT3 activation by inhibition of NADPH oxidase activation, and ERK/JNK and PKC pathways, resulting in a decrease in cell apoptosis; the therapeutic effect of NAC was verified in vivo.


CONCLUSIONS
The results presented herein show that carboplatin-mediated reactive oxygen species might signal calcineurin and NFAT3 activation in RTCs, whereas NAC and NFAT inhibitors reversed carboplatin-mediated RTC apoptosis, suggesting that oxidative stress-mediated NFAT3 activation is essential for carboplatin-mediated RTC apoptosis.
Lin
Heng
H
Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Sue
Yuh-Mou
YM
Chou
Ying
Y
Cheng
Ching-Feng
CF
Chang
Chih-Cheng
CC
Li
Hsiao-Fen
HF
Chen
Chien-Chang
CC
Juan
Shu-Hui
SH
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D016190:Carboplatin / Q000494:pharmacology* / Q000633:toxicity; D053148:Caspase 3 / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D019255:NADPH Oxidases / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D050050:Protein Carbonylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D014162:Transfection
D000970:Antineoplastic Agents; D050778:NFATC Transcription Factors; C494010:NFATC4 protein, human; D017382:Reactive Oxygen Species; D016190:Carboplatin; D008156:Luciferases; D019255:NADPH Oxidases; D053148:Caspase 3; D000111:Acetylcysteine