title: Release of overexpressed CypB activates ERK signaling through CD147 binding for hepatoma cell resistance to oxidative stress.
abstract: Cyclophilin, a cytosolic receptor for the immunosuppressive drug cyclosporin A, plays a role in diverse pathophysiologies along with its receptor, CD147. Although the interaction between cyclophilin A and CD147 is well established in inflammatory disease, that of cyclophilin B (CypB) with CD147 has not been fully explored, especially in cancer cell biology, and the exact molecular mechanism underlying such an association is poorly understood. In this study, we first identified high expression levels of CypB in 54 % of hepatocellular carcinoma patient tissues but in only 12.5 % of normal liver tissues. Then, we demonstrated that CypB overexpression protects human hepatoma cells against oxidative stress through its binding to CD147; this protective effect depends on the peptidyl prolyl isomerase activity of CypB. siRNA-mediated knockdown of CypB expression rendered hepatoma cells more vulnerable to ROS-mediated apoptosis. Furthermore, we also determined that a direct interaction between secreted CypB and CD147 regulates the extracellular signal-regulated kinase intracellular signaling pathway and is indispensible for the protective functions of CypB. For the first time, we demonstrated that CypB has an essential function in protecting hepatoma cells against oxidative stress through binding to CD147 and regulating the ERK pathway.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical Science and Engineering Research Center for Bioreaction to Reactive Oxygen Species, Biomedical Science Institute, School of Medicine, Kyung Hee University, #1 Hoegi-dong, Dongdaemoon-gu, Seoul, 130-701, Korea.
authors.forename: Kiyoon
authors.initials: K
authors.lastname: Kim
authors.forename: Hunsung
authors.initials: H
authors.lastname: Kim
authors.forename: Kwon
authors.initials: K
authors.lastname: Jeong
authors.forename: Min Hyung
authors.initials: MH
authors.lastname: Jung
authors.forename: Bum-Soo
authors.initials: BS
authors.lastname: Hahn
authors.forename: Kyung-Sik
authors.initials: KS
authors.lastname: Yoon
authors.forename: Byung Kwan
authors.initials: BK
authors.lastname: Jin
authors.forename: Geon-Ho
authors.initials: GH
authors.lastname: Jahng
authors.forename: Insug
authors.initials: I
authors.lastname: Kang
authors.forename: Joohun
authors.initials: J
authors.lastname: Ha
authors.forename: Wonchae
authors.initials: W
authors.lastname: Choe
mesh_terms: D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D051926:Basigin / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival; D021983:Cyclophilins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D015870:Gene Expression; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D008113:Liver Neoplasms / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018384:Oxidative Stress; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D046888:Tissue Array Analysis
chemical_list: D051017:Apoptosis Regulatory Proteins; C497886:BSG protein, human; D051926:Basigin; C081786:cyclophilin B; D006861:Hydrogen Peroxide; D020928:Mitogen-Activated Protein Kinases; D021983:Cyclophilins