title: Prx1 suppresses radiation-induced c-Jun NH2-terminal kinase signaling in lung cancer cells through interaction with the glutathione S-transferase Pi/c-Jun NH2-terminal kinase complex.
abstract: Radiotherapy is one of the major treatment modalities for lung cancer. Cell killing by ionizing radiation is mediated primarily through the reactive oxygen species (ROS) and ROS-driven oxidative stress. Prx1, a peroxiredoxin family member, was shown to be frequently elevated in lung cancer cells and tissues. Although the antioxidant function of Prx1 is expected to affect the radiotherapy response of lung cancer, the physiologic significance of its peroxidase activity in irradiated cells is unclear because the catalytic Cys52 is easily inactivated by ROS due to its overoxidation to sulfinic or sulfonic acid. In this study, we investigated the role of Prx1 in radiation sensitivity of human lung cancer cells, with special emphasis on the redox status of the catalytic Cys52. We found that overexpression of Prx1 enhances the clonogenic survival of irradiated cells and suppresses ionizing radiation-induced c-Jun NH2-terminal kinase (JNK) activation and apoptosis. The peroxidase activity of Prx1, however, is not essential for inhibiting JNK activation. The latter effect is mediated through its association with the glutathione S-transferase pi (GSTpi)-JNK complex, thereby preventing JNK release from the complex. Reduced JNK activation is observed when the peroxidase activity of Prx1 is compromised by Cys52 overoxidation or in the presence of the Cys52 to Ser52 mutant (Prx1C52S) lacking peroxidase activity. We show that both Prx1 and Prx1C52S interact with the GSTpi-JNK complex and suppress the release of JNK from the complex. Our study provides new insight into the antiapoptotic function of Prx1 in modulating radiosensitivity and provides the impetus to monitor the influence of Prx1 levels in the management of lung cancer.
authors.affiliation: Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
authors.forename: Yun-Jeong
authors.initials: YJ
authors.lastname: Kim
authors.forename: Weon-Sup
authors.initials: WS
authors.lastname: Lee
authors.forename: Clement
authors.initials: C
authors.lastname: Ip
authors.forename: Ho-Zoon
authors.initials: HZ
authors.lastname: Chae
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Park
authors.forename: Young-Mee
authors.initials: YM
authors.lastname: Park
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D001665:Binding Sites; D003545:Cysteine / Q000378:metabolism; D004789:Enzyme Activation / Q000528:radiation effects; D051549:Glutathione S-Transferase pi / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008175:Lung Neoplasms / Q000201:enzymology* / Q000378:metabolism / Q000532:radiotherapy*; D010084:Oxidation-Reduction; D054464:Peroxiredoxins / Q000096:biosynthesis / Q000378:metabolism*; D011836:Radiation Tolerance / Q000502:physiology; D015398:Signal Transduction / Q000528:radiation effects
chemical_list: D000975:Antioxidants; C515940:PRDX1 protein, human; D054464:Peroxiredoxins; D051549:Glutathione S-Transferase pi; D048031:JNK Mitogen-Activated Protein Kinases; D003545:Cysteine