title: Novel signaling axis for ROS generation during K-Ras-induced cellular transformation.
abstract: Reactive oxygen species (ROS) are well known to be involved in oncogene-mediated cellular transformation. However, the regulatory mechanisms underlying ROS generation in oncogene-transformed cells are unclear. In the present study, we found that oncogenic K-Ras induces ROS generation through activation of NADPH oxidase 1 (NOX1), which is a critical regulator for the K-Ras-induced cellular transformation. NOX1 was activated by K-Ras-dependent translocation of p47(phox), a subunit of NOX1 to plasma membrane. Of note, PKCδ, when it was activated by PDPK1, directly bound to the SH3-N domain of p47(phox) and catalyzed the phosphorylation on Ser348 and Ser473 residues of p47(phox) C-terminal in a K-Ras-dependent manner, finally leading to its membrane translocation. Notably, oncogenic K-Ras activated all MAPKs (JNK, ERK and p38); however, only p38 was involved in p47(phox)-NOX1-dependent ROS generation and consequent transformation. Importantly, K-Ras-induced activation of p38 led to an activation of PDPK1, which then signals through PKCδ, p47(phox) and NOX1. In agreement with the mechanism, inhibition of p38, PDPK1, PKCδ, p47(phox) or NOX1 effectively blocked K-Ras-induced ROS generation, anchorage-independent colony formation and tumor formation. Taken together, our findings demonstrated that oncogenic K-Ras activates the signaling cascade p38/PDPK1/PKCδ/p47(phox)/NOX1 for ROS generation and consequent malignant cellular transformation.
authors.affiliation: 1] Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea [2] Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan, Korea.
authors.forename: M-T
authors.initials: MT
authors.lastname: Park
authors.affiliation: 1] Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea [2] Low Dose Radiation Research Center, National Radiation Emergency Medical Science, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: Y
authors.initials: Y
authors.lastname: Suh
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: R-K
authors.initials: RK
authors.lastname: Kim
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: H
authors.initials: H
authors.lastname: Kim
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: E-J
authors.initials: EJ
authors.lastname: Lim
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: K-C
authors.initials: KC
authors.lastname: Yoo
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: G-H
authors.initials: GH
authors.lastname: Lee
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Division of Radiation Cancer Biology, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea.
authors.forename: S-G
authors.initials: SG
authors.lastname: Hwang
authors.affiliation: Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan, Korea.
authors.forename: J-M
authors.initials: JM
authors.lastname: Yi
authors.affiliation: Laboratory of Molecular Biochemistry, Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: S-J
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D064593:Heterografts; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C117307:KRAS protein, human; C528430:Kras protein, rat; C498751:Nsfl1c protein, rat; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; C553975:p37 protein, human; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; C402799:NOX1 protein, human; C000614712:NOX1 protein, rat; D048051:p38 Mitogen-Activated Protein Kinases; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins