title: The Roles of ROS and Caspases in TRAIL-Induced Apoptosis and Necroptosis in Human Pancreatic Cancer Cells.
abstract: Death signaling provided by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) can induce death in cancer cells with little cytotoxicity to normal cells; this cell death has been thought to involve caspase-dependent apoptosis. Reactive oxygen species (ROS) are also mediators that induce cell death, but their roles in TRAIL-induced apoptosis have not been elucidated fully. In the current study, we investigated ROS and caspases in human pancreatic cancer cells undergoing two different types of TRAIL-induced cell death, apoptosis and necroptosis. TRAIL treatment increased ROS in two TRAIL-sensitive pancreatic cancer cell lines, MiaPaCa-2 and BxPC-3, but ROS were involved in TRAIL-induced apoptosis only in MiaPaCa-2 cells. Unexpectedly, inhibition of ROS by either N-acetyl-L-cysteine (NAC), a peroxide inhibitor, or Tempol, a superoxide inhibitor, increased the annexin V-/propidium iodide (PI)+ early necrotic population in TRAIL-treated cells. Additionally, both necrostatin-1, an inhibitor of receptor-interacting protein kinase 1 (RIP1), and siRNA-mediated knockdown of RIP3 decreased the annexin V-/PI+ early necrotic population after TRAIL treatment. Furthermore, an increase in early apoptosis was induced in TRAIL-treated cancer cells under inhibition of either caspase-2 or -9. Caspase-2 worked upstream of caspase-9, and no crosstalk was observed between ROS and caspase-2/-9 in TRAIL-treated cells. Together, these results indicate that ROS contribute to TRAIL-induced apoptosis in MiaPaCa-2 cells, and that ROS play an inhibitory role in TRAIL-induced necroptosis of MiaPaCa-2 and BxPC-3 cells, with caspase-2 and -9 playing regulatory roles in this process.
authors.affiliation: Department of Biochemistry and Molecular Biology, Ningxia Medical University, Shengli Street, Yinchuan, China; Department of Immunology, Shimane University Faculty of Medicine, Izumi, Shimane, Japan.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Immunology, Shimane University Faculty of Medicine, Izumi, Shimane, Japan.
authors.forename: Nanae
authors.initials: N
authors.lastname: Harashima
authors.affiliation: Department of Immunology, Shimane University Faculty of Medicine, Izumi, Shimane, Japan.
authors.forename: Tamami
authors.initials: T
authors.lastname: Moritani
authors.affiliation: Department of Biochemistry and Molecular Biology, Ningxia Medical University, Shengli Street, Yinchuan, China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Immunology, Shimane University Faculty of Medicine, Izumi, Shimane, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Harada
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D003497:Cyclic N-Oxides / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D013113:Spin Labels; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*
chemical_list: D017304:Annexin A5; D003497:Cyclic N-Oxides; D007093:Imidazoles; D007211:Indoles; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D013113:Spin Labels; D053221:TNF-Related Apoptosis-Inducing Ligand; C507699:necrostatin-1; C119705:RIPK3 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D020169:Caspases; C001803:tempol; D000111:Acetylcysteine