title: Tanshinone IIA Facilitates TRAIL Sensitization by Up-regulating DR5 through the ROS-JNK-CHOP Signaling Axis in Human Ovarian Carcinoma Cell Lines.
abstract: Tanshinone IIA (TIIA) extracted from Salvia miltiorrhiza has been shown to possess antitumor and TRAIL-sensitizing activity. The involvement of DR5 in the mechanism whereby TIIA exerts its effects is unknown. This study aimed to explore the mechanism underlying TIIA augmentation of TRAIL-induced cell death in ovarian carcinoma cells. Cell viability was determined by MTS assay. Real-time RT-PCR and Western blotting were used to assess the mRNA and protein expression of relating signaling proteins. Transcriptional activation was explored by a dual-luciferase reporter assay. We found that TIIA sensitized human ovarian carcinoma cells to TRAIL-induced extrinsic apoptosis. Combined treatment with subtoxic concentrations of TIIA and TRAIL was more effective than single treatments with respect to cytotoxicity, clonogenic inhibition, and the induction of caspase-8 and PARP activity in ovarian carcinoma cell lines TOV-21G and SKOV3. TIIA induced DR5 protein and mRNA expression in a concentration-dependent manner. DR5/Fc treatment markedly suppressed the TRAIL cytotoxicity enhanced by TIIA. These results indicate that DR5 plays an essential role in TIIA-induced TRAIL sensitization and that induction of DR5 by TIIA is mediated through the up-regulation of CCAAT/enhancer-binding protein homologous protein (CHOP). Knockdown of CHOP gene expression by shRNA attenuated DR5 up-regulation and rescued cell viability under the treatment of TIIA-TRAIL combination. TIIA promoted JNK-mediated signaling to up-regulated CHOP and thereby inducing DR5 expression as shown by the ability of a JNK inhibitor to potently suppress the TIIA-mediated activation of CHOP and DR5. In addition, the quenching of ROS using NAC prevented the induction of JNK phosphorylation and CHOP induction. Furthermore, inhibition of ROS by NAC significantly attenuated TRAIL sensitization by TIIA. Taken together, these data suggest that TIIA enhances TRAIL-induced apoptosis by upregulating DR5 receptors through the ROS-JNK-CHOP signaling axis in human ovarian carcinoma cells.
authors.forename: Chia-Che
authors.initials: CC
authors.lastname: Chang
authors.affiliation: #Division of Biotechnology, Taiwan Agricultural Research Institute, Wufeng, Taiwan.
authors.forename: Cheng-Ping
authors.initials: CP
authors.lastname: Kuan
authors.affiliation: †Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
authors.forename: Jyun-Yi
authors.initials: JY
authors.lastname: Lin
authors.affiliation: #Division of Biotechnology, Taiwan Agricultural Research Institute, Wufeng, Taiwan.
authors.forename: Jui-Sheng
authors.initials: JS
authors.lastname: Lai
authors.affiliation: †Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
authors.forename: Tsing-Fen
authors.initials: TF
authors.lastname: Ho
mesh_terms: D045784:Abietanes / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005260:Female; D006801:Humans; D020935:MAP Kinase Signaling System; D008954:Models, Biological; D010051:Ovarian Neoplasms / Q000188:drug therapy; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*; D051742:Transcription Factor CHOP / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D045784:Abietanes; D000970:Antineoplastic Agents; C497249:DDIT3 protein, human; D017382:Reactive Oxygen Species; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C021751:tanshinone; D051742:Transcription Factor CHOP