title: Accumulation of RNA-dependent protein kinase (PKR) in the nuclei of lung cancer cells mediates radiation resistance.
abstract: We have previously demonstrated that radiation induced cell death in PKR (-/-) deficient mouse embryo fibroblasts (MEFs) but not in PKR (+/+) wild type MEFs. Our study indicated that PKR can also be involved in survival pathways following radiation therapy through activation of the AKT survival pathways in these MEFs is mediated in part through PKR. The role of PKR on radiation sensitivity in cancer cells has not been evaluated. In this study, we demonstrated that radiation treatment causes nuclear translocation of PKR in human lung cancer cells. The transduction of lung cancer cells with a dominant negative adenoviral PKR vector blocks nuclear translocation of PKR and leads to the reversal of radiation resistance. Plasmid transduction of lung cancer cells with nuclear targeted wild type PKR vectors also increased radiation resistance. This effect is selectively abrogated by plasmid transduction of dominant negative PKR vectors which restore radiation sensitivity. These findings suggest a novel role for PKR in lung cancer cells as a mediator of radiation resistance possibly through translocation of the protein product to the nucleus.
authors.affiliation: Departments of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.|Current Address: Department of Oncology Radiotherapy, the Cancer Hospital of Harbin Medical University, Harbin, China.
authors.forename: Chuncheng
authors.initials: C
authors.lastname: Hao
authors.affiliation: Departments of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Ruping
authors.initials: R
authors.lastname: Shao
authors.affiliation: Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Uma
authors.initials: U
authors.lastname: Raju
authors.affiliation: Departments of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Bingliang
authors.initials: B
authors.lastname: Fang
authors.affiliation: Departments of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Swisher
authors.affiliation: Departments of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Apar
authors.initials: A
authors.lastname: Pataer
mesh_terms: D000072283:A549 Cells; D000256:Adenoviridae / Q000235:genetics; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000201:enzymology; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy*; D011836:Radiation Tolerance; D014162:Transfection; D019892:eIF-2 Kinase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: C000602769:EIF2AK2 protein, human; D019892:eIF-2 Kinase
keywords: PKR; lung cancer; radiation sensitivity