The Roles of ROS and Caspases in TRAIL-Induced Apoptosis and Necroptosis in Human Pancreatic Cancer Cells

• Published in: PloS one 2015-05, Vol.10 (5), p.e0127386-e0127386
• Main Authors: Zhang, Min, Harashima, Nanae, Moritani, Tamami, Huang, Weidong, Harada, Mamoru
• Format: Article
• Language: English
• Subjects: Acetylcysteine; Acetylcysteine - pharmacology; Analysis; Annexin A5 - metabolism; Annexin V; Apoptosis; Apoptosis - drug effects; Apoptosis - physiology; Autophagy; Biochemistry; Cancer; Cancer cells; Care and treatment; Caspase; Caspase-2; Caspase-9; Caspases - metabolism; Cell death; Cell Death - drug effects; Cell Death - physiology; Cell Line, Tumor; Crosstalk; Cyclic N-Oxides - pharmacology; Cysteine; Cytotoxicity; Deoxyribonucleic acid; Diagnosis; DNA; DNA damage; Humans; Imidazoles - pharmacology; Immunology; Indoles - pharmacology; Inhibition; Inhibitors; Iodides; Kinases; Ligands; Medicine; Molecular biology; Mortality; N-Acetyl-L-cysteine; Necroptosis; Oxygen; Pancreatic cancer; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - pathology; Peroxide; Propidium iodide; Protein kinase; Proteins; Reactive oxygen species; Reactive Oxygen Species - metabolism; Receptor-Interacting Protein Serine-Threonine Kinases - genetics; Receptor-Interacting Protein Serine-Threonine Kinases - metabolism; Risk factors; RNA, Small Interfering; Signaling; siRNA; Spin Labels; Superoxide; Superoxides; Tempol; TNF-Related Apoptosis-Inducing Ligand - pharmacology; Toxicity; TRAIL protein; Tumor cell lines; Tumor necrosis factor; Tumor necrosis factor-TNF; University faculty
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0127386

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.