Targeting nitrative stress for attenuating cisplatin-induced downregulation of cochlear LIM domain only 4 and ototoxicity.
Cisplatin-induced ototoxicity remains a primary dose-limiting adverse effect of this highly effective anticancer drug. The clinical utility of cisplatin could be enhanced if the signaling pathways that regulate the toxic side-effects are delineated. In previous studies, we reported cisplatin-induced nitration of cochlear proteins and provided the first evidence for nitration and downregulation of cochlear LIM domain only 4 (LMO4) in cisplatin ototoxicity. Here, we extend these findings to define the critical role of nitrative stress in cisplatin-induced downregulation of LMO4 and its consequent ototoxic effects in UBOC1 cell cultures derived from sensory epithelial cells of the inner ear and in CBA/J mice. Cisplatin treatment increased the levels of nitrotyrosine and active caspase 3 in UBOC1 cells, which was detected by immunocytochemical and flow cytometry analysis, respectively. The cisplatin-induced nitrative stress and apoptosis were attenuated by co-treatment with SRI110, a peroxynitrite decomposition catalyst (PNDC), which also attenuated the cisplatin-induced downregulation of LMO4 in a dose-dependent manner. Furthermore, transient overexpression of LMO4 in UBOC1 cells prevented cisplatin-induced cytotoxicity while repression of LMO4 exacerbated cisplatin-induced cell death, indicating a direct link between LMO4 protein levels and cisplatin ototoxicity. Finally, auditory brainstem responses (ABR) recorded from CBA/J mice indicated that co-treatment with SRI110 mitigated cisplatin-induced hearing loss. Together, these results suggest that cisplatin-induced nitrative stress leads to a decrease in the levels of LMO4, downregulation of LMO4 is a critical determinant in cisplatin-induced ototoxicity, and targeting peroxynitrite could be a promising strategy for mitigating cisplatin-induced hearing loss.
Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Family Medicine and Public Health Sciences, Wayne State University, Detroit, MI 48202, USA. Electronic address: sjamesdaniel@wayne.edu.
Samson
S
Jamesdaniel
Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA.
Rajamani
R
Rathinam
Department of Pharmaceutical Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA.
William L
WL
Neumann
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D002945:Cisplatin / Q000633:toxicity*; D003051:Cochlea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000187:drug effects*; D016057:Evoked Potentials, Auditory, Brain Stem; D034381:Hearing Loss / Q000139:chemically induced / Q000378:metabolism*; D060588:LIM Domain Proteins / Q000378:metabolism*; D017895:Manganese Compounds / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008808:Mice, Inbred CBA; D030421:Peroxynitrous Acid / Q000031:analogs & derivatives; D015843:Serpins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D060588:LIM Domain Proteins; C491976:Lmo4 protein, mouse; D017895:Manganese Compounds; D008565:Membrane Proteins; D015843:Serpins; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; C106610:Serpinb9 protein, mouse; D002945:Cisplatin
Cisplatin; Cochlea; Hearing loss; LMO4; Ototoxicity; Protein nitration