Flunarizine induces Nrf2-mediated transcriptional activation of heme oxygenase-1 in protection of auditory cells from cisplatin.
We investigated the cytoprotective mechanisms of flunarizine in cisplatin-induced death of auditory cells. Concomitant with an increase in viability, treatment with flunarizine resulted in a marked dissociation of Nrf2/Keap1 and subsequent intranuclear translocation of Nrf2, which was mediated by PI3K-Akt signaling. Overexpression of Nrf2 protected cells from cisplatin along with transcriptional activation of ARE to generate heme oxygenase-1 (HO-1). Pretreatment with flunarizine predominantly increased the transcriptional activity of HO-1 among Nrf2-driven transcripts, including HO-1, NQO1, GCLC, GCLM, GST micro-1, and GSTA4. Furthermore, both pharmacological inhibition and siRNA transfection of HO-1 completely abolished the flunarizine-mediated protection of HEI-OC1 cells and the primary rat (P2) organ of Corti explants from cisplatin. These results suggest that Nrf2-driven transcriptional activation of ARE through PI3K-Akt signaling augments the generation of HO-1, which may be a critically important determinant in cellular response toward cisplatin and the cytoprotective effect of flunarizine against cisplatin.
Vestibulocochlear Research Center & Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk 570-749, Korea.
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So
H-J
HJ
Kim
J-H
JH
Lee
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JH
Lee
S-Y
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Park
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Park
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YH
Kim
J-K
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Kim
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KM
Lee
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Kim
S-Y
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Chung
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Jang
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Moon
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Chung
R-K
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Park
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D002460:Cell Line; D002945:Cisplatin / Q000633:toxicity*; D018076:DNA, Complementary / Q000235:genetics; D005444:Flunarizine / Q000494:pharmacology*; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000235:genetics*; D066298:In Vitro Techniques; D051379:Mice; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D009925:Organ of Corti / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects
D000975:Antioxidants; D018076:DNA, Complementary; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; C495637:Nfe2l2 protein, rat; D034741:RNA, Small Interfering; D051547:Heme Oxygenase-1; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D002945:Cisplatin; D005444:Flunarizine