title: Annexin A2 is a novel cellular redox regulatory protein involved in tumorigenesis.
abstract: Annexins are a structurally related family of calcium and phospholipid-binding proteins that are involved in the regulation of a wide range of molecular and cellular processes. Annexin A2 is unique among the annexins in that it possesses redox sensitive cysteine(s). The ubiquitous and abundant expression of ANXA2 in cells and its reactivity with hydrogen peroxide led us to hypothesize that this protein could play a role in cellular redox regulation. Here we show that ANXA2 protein levels are induced by hydrogen peroxide. Furthermore, depletion of ANXA2 resulted in the elevation of cellular reactive oxygen species (ROS) upon oxidative stress, increased activation of the ROS-induced pro-apoptotic kinases, JNK, p38 and Akt and elevated sensitivity to ROS-mediated cellular damage/death. ANXA2-null mice showed significantly elevated protein oxidation in the liver and lung tissues compared to WT mice. ANXA2 depleted cancer cells showed enhanced cellular protein oxidation concomitant with decreased tumor growth compared to control cancer cells and both the protein oxidation and tumor growth deficit were reversed by the antioxidant N-acetyl cysteine, indicating that ANXA2 redox regulatory function plays a major role in tumorigenesis. Ex-vivo human cancer studies showed that up-regulation of the reduced form of ANXA2 is associated with protection of the tumor proteins from oxidation. In summary, our results indicate that ANXA2 redox regulatory function plays an important role protecting cells from oxidative stress, particularly during tumorigenesis.
authors.affiliation: Department of Biochemistry, Dalhousie University, Halifax , Nova Scotia, B3H 4R2, Canada.
authors.forename: Patricia Alexandra
authors.initials: PA
authors.lastname: Madureira
authors.forename: Richard
authors.initials: R
authors.lastname: Hill
authors.forename: Victoria Ann
authors.initials: VA
authors.lastname: Miller
authors.forename: Carman
authors.initials: C
authors.lastname: Giacomantonio
authors.forename: Patrick Wing Kwong
authors.initials: PW
authors.lastname: Lee
authors.forename: David Morton
authors.initials: DM
authors.lastname: Waisman
mesh_terms: D000818:Animals; D017306:Annexin A2 / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D017306:Annexin A2; D002135:Calcium-Binding Proteins; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D051057:Proto-Oncogene Proteins c-akt; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases