title: Activation of a nuclear factor of activated T-lymphocyte-3 (NFAT3) by oxidative stress in carboplatin-mediated renal apoptosis.
abstract: 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.
authors: Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors: Heng
authors: H
authors: Lin
authors: Yuh-Mou
authors: YM
authors: Sue
authors: Ying
authors: Y
authors: Chou
authors: Ching-Feng
authors: CF
authors: Cheng
authors: Chih-Cheng
authors: CC
authors: Chang
authors: Hsiao-Fen
authors: HF
authors: Li
authors: Chien-Chang
authors: CC
authors: Chen
authors: Shu-Hui
authors: SH
authors: Juan
mesh_terms: 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
chemical_list: 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