title: Inactivation of Src-to-ezrin pathway: a possible mechanism in the ouabain-mediated inhibition of A549 cell migration.
abstract: Ouabain, a cardiac glycoside found in plants, is primarily used in the treatment of congestive heart failure and arrhythmia because of its ability to inhibit Na(+)/K(+)-ATPase pump. Recently ouabain has been shown to exert anticancer effects but the underlying mechanism is not clear. Here, we explored the molecular mechanism by which ouabain exerts anticancer effects in human lung adenocarcinoma. Employing proteomic techniques, we found 7 proteins downregulated by ouabain in A549 including p-ezrin, a protein associated with pulmonary cancer metastasis in a dose-dependent manner. In addition, when the relative phosphorylation levels of 39 intracellular proteins were compared between control and ouabain-treated A549 cells, p-Src (Y416) was also found to be downregulated by ouabain. Furthermore, western blot revealed the ouabain-mediated downregulation of p-FAK (Y925), p-paxillin (Y118), p130CAS, and Na(+)/K(+)-ATPase subunits that have been shown to be involved in the migration of cancer cells. The inhibitory effect of ouabain and Src inhibitor PP2 on the migration of A549 cells was confirmed by Boyden chamber assay. Anticancer effects of ouabain in A549 cells appear to be related to its ability to regulate and inactivate Src-to-ezrin signaling, and proteins involved in focal adhesion such as Src, FAK, and p130CAS axis are proposed here.
authors: Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul 120-750, Republic of Korea.
authors: Hye Kyoung
authors: HK
authors: Shin
authors: Laboratory of Translational Therapeutics, Bio-Organic Science Division, Pharmacology Research Center, Korea Research Institute of Chemical Technology, Daejeon 305-600, Republic of Korea.
authors: Byung Jun
authors: BJ
authors: Ryu
authors: Laboratory of Translational Therapeutics, Bio-Organic Science Division, Pharmacology Research Center, Korea Research Institute of Chemical Technology, Daejeon 305-600, Republic of Korea.
authors: Sik-Won
authors: 0000-0003-1726-2536
authors: SW
authors: Choi
authors: Laboratory of Translational Therapeutics, Bio-Organic Science Division, Pharmacology Research Center, Korea Research Institute of Chemical Technology, Daejeon 305-600, Republic of Korea.
authors: Seong Hwan
authors: 0000-0002-3540-0448
authors: SH
authors: Kim
authors: Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul 120-750, Republic of Korea.
authors: Kyunglim
authors: 0000-0001-6524-0185
authors: K
authors: Lee
mesh_terms: D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D010042:Ouabain / Q000494:pharmacology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*; D000099149:Ezrin
chemical_list: D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; D010042:Ouabain; D019061:src-Family Kinases; D000099149:Ezrin