Piperine protects cisplatin-induced apoptosis via heme oxygenase-1 induction in auditory cells

Piperine is a major component of black pepper, Piper nigrum Linn, used widely in traditional medicine. In this study, we examined whether piperine could protect House Ear Institute-Organ of Corti I (HET-OCI) cells against cisplatin-induced apoptosis through the induction of heme oxygenase (HO)-1 expression. Piperine (10-100 mu M) induced the expression of HO-I in dose- and time-dependent manners. Piperine also induced antioxidant response element-luciferase and translocated nuclear factor-E2-related factor-2 (Nrf2) to nucleus. Piperine activated the c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase and p38 mitogen-activated protein kinase (MAPK) pathways, and the JNK pathway played an important role in piperine-induced HO-I expression. Piperine protected the cells against cisplatin-induced apoptosis. The protective effect of piperine was abrogated by zinc protoporphyrin IX, an HO inhibitor, and antisense oligodeoxynucleotides against HO-I gene. These results demonstrate that the expression of HO-I by piperine is mediated by both JNK pathway and Nrf2, and the expression inhibits cisplatin-induced apoptosis in HEI-OCl cells. (c) 2007 Elsevier Inc. All rights reserved.